GAS-PHASE HOMOGENEOUS OXIDATIVE DEHYDROGENATION AND COUPLING OF ORGANIC MOLECULES
20210395171 · 2021-12-23
Inventors
Cpc classification
Y02P20/52
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
C07D303/04
CHEMISTRY; METALLURGY
International classification
Abstract
Disclosed are gas-phase ODH and OCP processes for converting alkanes (e.g., C.sub.2H.sub.6 and C.sub.3H.sub.8) to alkenes (e.g., C.sub.2H.sub.4 and C.sub.3H.sub.6) or oxygenates (e.g., methanol, ethanol, isopropanol, or propylene oxide) or converting alkenes (e.g., ethylene and propene) and oxygenates (e.g., methanol, ethanol, isopropanol or propylene oxide) to longer carbon-chain alkenes or longer carbon-chain alkanes with or without solid catalysts.
Claims
1. A gas-phase oxidative dehydrogenation (ODH) process for converting an alkane to an alkene or an oxygenate, comprising: flowing a feed gas through a heated reaction zone within a reactor, wherein the feed gas comprises an alkane, an oxidizing agent, and a radical initiator, wherein: the heated reaction zone has a temperature of about 363 to about 1000 K; and the heated reaction zone is a space or a combination of a space and an inert solid surface.
2. The process of claim 1, wherein the alkane is a C.sub.1-20 alkane.
3. The process of claim 2, wherein the alkane is ethane or propane.
4. The process of any one of claims 1-3, wherein the oxidizing agent is oxygen, nitrous oxide, or carbon dioxide.
5. The process of claim 4, wherein the oxidizing agent is oxygen.
6. The process of claim 5, wherein the oxygen is present at about 3 kPa to about 50 kPa in the feed gas.
7. The process of any one of claims 1-6, wherein the radical initiator is nitric oxide, nitrogen dioxide, a halogen, an azide compound, or organic peroxide.
8. The process of claim 7, wherein the radical initiator is nitric oxide or nitrogen dioxide.
9. The process of claim 8, wherein the radical initiator is nitric oxide present at about 1 to about 500 ppm in the feed gas.
10. The process of any one of claims 1-9, wherein the feed gas further comprises one or more hydrocarbons.
11. The process of any one of claims 1-10, wherein the feed gas further comprises an inert diluent.
12. The process of claim 11, wherein the inert diluent is helium, nitrogen, carbon dioxide or carbon monoxide.
13. The process of claim 12, wherein the inert diluent is helium or nitrogen.
14. The process of any one of claims 1-13, wherein the feed gas further comprises water vapor.
15. The process of any one of claims 1-14, wherein the process is performed at about 1 to about 5 atmospheric pressure.
16. The process of claim 15, wherein the process is performed at about 1 atmospheric pressure.
17. The process of any one of claims 1-16, wherein the heated reaction zone has a temperature of about 363 to about 873 K.
18. The process of any one of claims 1-17, wherein the process is performed in the absence of a solid catalyst.
19. The process of any one of claims 1-17, wherein the process is performed with the presence of a solid catalyst.
20. The process of claim 19, wherein the solid catalyst is VO.sub.x/SiO.sub.2.
21. The process of claim 19, wherein the solid catalyst is used at an amount of about 20 wt % to about 60 wt %.
22. The process of claim 19, wherein the solid catalyst is used at an amount of about 40 wt %.
23. The process of any one of claims 1-22, wherein the alkane is propane, the oxidizing agent is oxygen, the radical initiator is nitric oxide or nitrogen dioxide.
24. The process of any one of claims 1-23, wherein the alkene formed is ethylene or propylene.
25. The process of any one of claims 1-23, wherein the oxygenate formed is propylene oxide.
26. The process of any one of claims 1-25, wherein the reactor is a straight quartz tube, a U-shaped quartz tube, a straight stainless steel tube, or a U-shaped stainless steel tube.
27. The process of claim 26, wherein the reactor is a U-shaped quartz tube.
28. A gas-phase coupling process for converting a hydrocarbon feedstock to an effluent stream, comprising: flowing a feed gas comprising a hydrocarbon feedstock, an oxidizing agent, and a radical initiator through a heated reaction zone within a reactor; wherein: the hydrocarbon feedstock comprises an oxygenate, and a C.sub.1-C.sub.6 alkane or a C.sub.2-C.sub.6 alkene; the effluent stream comprises a C.sub.7-C.sub.20 alkane or a C.sub.7-C.sub.20 alkene or both; the heated reaction zone has a temperature of about 363 to about 1000 K; and the heated reaction zone is a space or a combination of a space and an inert solid surface, whereby the effluent stream is produced.
29. A gas-phase coupling process for converting an alkene and an oxygenate to a longer carbon-chain alkene or a longer carbon-chain alkane, comprising: flowing a feed gas through a heated reaction zone within a reactor, wherein the feed gas comprises an alkene, an oxygenate, an oxidizing agent, and a radical initiator, wherein: the heated reaction zone has a temperature of about 363 to about 1000 K; and the heated reaction zone is a space or a combination of a space and an inert solid surface.
30. The process of claim 29, wherein the alkene in the feed gas comprises a C.sub.2-20 alkene.
31. The process of claim 30, wherein the alkene in the feed gas comprises a C.sub.2-6 alkene.
32. The process of claim 31, wherein the alkene in the feed gas comprises ethylene.
33. The process of any one of claims 28-32, wherein the oxygenate in the feed gas comprises C.sub.1-6 alcohol.
34. The process of claim 33, wherein the oxygenate in the feed gas comprises methanol, ethanol or isopropanol.
35. The process of any one of claims 28-34, wherein the oxidizing agent is oxygen.
36. The process of claim 35, wherein the oxygen is present at about 3 kPa to about 50 kPa in the feed gas.
37. The process of any one of claims 28-36, wherein the radical initiator is nitric oxide present at about 1 to about 500 ppm in the feed gas.
38. The process of any one of claims 28-37, wherein the feed gas further includes an inert diluent.
39. The process of claim 38, wherein the inert diluent is helium, nitrogen, carbon dioxide, or carbon monoxide.
40. The process of claim 39, wherein the inert diluent is helium or nitrogen.
41. The process of any one of claims 28-40, wherein the feed gas further comprises water vapor.
42. The process of any one of claims 28-41, wherein the process is performed at about 1 to about 5 atmospheric pressure.
43. The process of claim 42, wherein the process is performed at about 1 atmospheric pressure.
44. The process of any one of claims 28-43, wherein the process is performed at a temperature from 363-873 K.
45. The process of any one of claims 28-44, wherein the process is performed in the absence of a solid catalyst.
46. The process of any one of claims 28-45, wherein the lower alkene is propene or ethylene, the oxygenate is methanol, the oxidizing agent is oxygen, and the radical initiator is nitric oxide or nitrogen dioxide.
47. The process of any one of claims 28-46, wherein the reactor is a straight quartz tube, a U-shaped quartz tube, a straight stainless steel tube, or a U-shaped stainless steel tube.
48. The process of claim 47, wherein the reactor is a U-shaped quartz tube.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION
[0075] Described in detail below are gas-phase ODH and OCP processes of the present invention for converting alkanes (e.g., C.sub.2H.sub.6 and C.sub.3H.sub.8) to alkenes (e.g., C.sub.2H.sub.4 and C.sub.3H.sub.6) or oxygenates (e.g., methanol, ethanol, isopropanol, or propylene oxide) or converting alkenes (e.g., ethylene and propene) and oxygenates (e.g., methanol, ethanol, isopropanol, or propylene oxide) to longer carbon-chain alkenes, or longer carbon-chain alkanes with or without solid catalysts by contacting alkanes or contacting alkenes and oxygenates with an oxidizing agent (e.g., O.sub.2) and a trace amount of a radical initiator (e.g., nitric oxide NO or nitrogen dioxide NO.sub.2) in a reactor, with optional addition of water vapor, gaseous diluents (e.g., helium He or nitrogen N2), and inert solids (e.g., nitric acid washed SiO.sub.2 powders).
[0076] The reaction conditions are optimized to provide high alkane conversion and high alkene selectivity by varying certain parameters such as reaction temperature, concentrations of reactants, and reactor volume.
[0077] Only a trace amount of the radical initiator, e.g., 1-500 ppm NO, needs to be present to obtain optimum yields. Unexpectedly, high oxidizing agent concentrations (e.g., 10 kPa-50 kPa O.sub.2) lead to better alkene yields, which is counterintuitive and not logically derived from previous studies to minimize O.sub.2 in the feed or use non-oxidative processes for such conversions. Indeed, a combination of NO and O.sub.2 at optimal concentrations leads to higher production of the specific radicals that perform conversion of an alkane to an alkene or of an alkene and an oxygenate to a longer carbon-chain alkene with excellent selectivity. Of note, NO acts as a radical initiator and may also be considered as a radical as it contains an unpaired electron.
[0078] Adding water vapor can also improve the concentration of the specific radicals discussed above, leading to high selectivity and high conversion rate.
[0079] Inert diluents can be used to control the concentrations of reactive components and radical initiators. The total pressure of the feed gas is typically 1 atmosphere. If the total pressure of the active components is lower than 1 atmosphere, inert diluents can be added as balance. Further, as pure NO, a radical initiator, is very toxic, its dilution with an inert diluent is preferred.
[0080] The ODH process of this invention using propane in a feed gas leads to >80% propylene selectivity and >90% total alkene (propylene+ethylene) selectivity with near 5% propane conversion. Operating near 10% single-pass conversion with recycle results in 80% propylene yield. The yield can be further improved via process optimization.
[0081] In one study described below (Example 2), a feed gas including 3 kPa C.sub.2H.sub.6, 10 kPa O.sub.2, 0.03 kPa NO, and balance He was added to a 12 cm.sup.3 reactor maintained at 823 K. >75% C.sub.2H.sub.6 conversions and >40% C.sub.2H.sub.4 yields were obtained.
[0082] In another study described below (Example 3), a feed gas including 3 kPa C.sub.3H.sub.8, 10 kPa O.sub.2, 0.005 kPa NO, and balance He was added to a 12 cm.sup.3 reactor at 773 K. >70% C.sub.3H.sub.8 conversions in a single pass through the reactor, >24% C.sub.3H.sub.6 yields, and >42% total alkene (C.sub.2H.sub.4+C.sub.3H.sub.6) yields were obtained. Extrapolation of conversion studies with variation of temperature and pressures of all reactants and addition of water vapor indicates that much higher conversion rates are achievable.
[0083] The present invention provides a cost-effective solution for small scale plants. The ODH and OCP processes of this invention lead to lower costs as much simpler reactors, without movable parts or catalyst regeneration mechanisms, can be used. Indeed, these reactors are much less expensive and easier to handle than catalytic reactors. It can also lead to lower operating costs as (i) exothermic reaction avoids the need for costly external heat, (ii) costs for catalysts and their regeneration can be entirely avoided, and (iii) pumping costs for avoiding pressure drops caused by catalyst beds are lower. These advantages can lead to half the utility cost and much lower effective raw material cost while maintaining similar yields.
[0084] The ODH and OCP processes of this invention can play a role in helping mitigate flaring of wet shale gas and wet-natural gas by allowing small-scale economical plants built near their production facilities to better utilize these resources. It can be an effective solution to current bulky large-scale technologies. Regulations on flaring will make such processes more attractive in near future.
[0085] Also, the processes can be applied to produce valuable alkenes from other larger hydrocarbons and specialty products with specific alkene isomers, which are in low yield by conventional processes due to their lower thermodynamic stability. Butane, isobutane, hexane, cyclohexane, and methyl cyclohexane all can be used for commercial production of their corresponding alkenes.
[0086] When NO is used as a radical initiator, the products of the ODH and OCP processes contain trace amounts of nitrates and other nitrosyl compounds, which can be easily detected using highly sensitive analytical techniques such as infrared spectroscopy and mass spectrometry.
[0087] The objective and advantages of the present invention are illustrated in Examples 1-10 below. The following procedures were used for preparing the catalysts and analyzing the data described in the examples.
[0088] Vanadium and molybdenum oxides catalysts supported on silica (VO.sub.x/SiO.sub.2, MoO.sub.x/SiO.sub.2) were prepared by wet impregnation of ammonium metavanadate and ammonium helptamolybdate precursors (Sigma Aldrich), respectively, on SiO.sub.2 powders (Sigma Aldrich).
[0089] ODH reactions were carried out at near-atmospheric pressures (101.3 kPa) in a U-shaped quartz tube (¼″ OD) with a bulb and a quartz frit designed for holding inert or catalytic solids during the flow of gaseous reactants (
[0090] The term “conversion”, “selectivity”, “yield”, and “residence time” are used to describe the results of reactions and performance of the processes described in the examples below. “Conversion” refers to the percentage of the fed alkane or fed alkene and oxygenate converted to products at the reactor effluent. “Selectivity” for a product (e.g., C.sub.2H.sub.4, C.sub.3H.sub.6, CO, or CO.sub.2) is defined as the percentage of the carbon atoms of the reacted alkane or reacted alkene and oxygenate retained in that specific product. “Yield” of a specific product reflects the multiplication of alkane conversion or alkene and oxygenate conversion and selectivity for that product. “Residence time” of a species represents the reactor volume (in m.sup.3) divided by the moles of that species fed per second to the reactor.
[0091] Without further elaboration, it is believed that one skilled in the art can, based on the above description, utilize the present invention to its fullest extent. The specific embodiments described in Examples 1-15 below are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever. All publications cited herein are incorporated by reference.
[0092] In one aspect, provided are gas-phase oxidative dehydrogenation (ODH) processes for converting an alkane to an alkene or an oxygenate, comprising:
flowing a feed gas through a heated reaction zone within a reactor, wherein the feed gas comprises an alkane, an oxidizing agent, and a radical initiator,
wherein:
the heated reaction zone has a temperature of about 363 to about 1000 K; and
the heated reaction zone is a space or a combination of a space and an inert solid surface.
[0093] In certain embodiments, the alkane is a C.sub.1-20 alkane.
[0094] In certain embodiments, the alkane is ethane or propane.
[0095] In certain embodiments, the oxidizing agent is oxygen, nitrous oxide, or carbon dioxide.
[0096] In certain embodiments, the oxidizing agent is oxygen.
[0097] In certain embodiments, oxygen is present at about 3 kPa to about 50 kPa in the feed gas.
[0098] In certain embodiments, the radical initiator is nitric oxide, nitrogen dioxide, a halogen, an azide compound, or organic peroxide.
[0099] In certain embodiments, the radical initiator is nitric oxide or nitrogen dioxide.
[0100] In certain embodiments, the radical initiator is nitric oxide present at about 1 to about 500 ppm in the feed gas.
[0101] In certain embodiments, the feed gas further comprises one or more hydrocarbons.
[0102] In certain embodiments, the feed gas further comprises an inert diluent.
[0103] In certain embodiments, the inert diluent is helium, nitrogen, carbon dioxide or carbon monoxide.
[0104] In certain embodiments, the inert diluent is helium or nitrogen.
[0105] In certain embodiments, the feed gas further comprises water vapor.
[0106] In certain embodiments, the process is performed at about 1 to about 5 atmospheric pressure.
[0107] In certain embodiments, the process is performed at about 1 atmospheric pressure.
[0108] In certain embodiments, the heated reaction zone has a temperature of about 363 to about 873 K.
[0109] In certain embodiments, the process is performed in the absence of a solid catalyst.
[0110] In certain embodiments, the process is performed with the presence of a solid catalyst.
[0111] In certain embodiments, the solid catalyst is VO.sub.x/SiO.sub.2.
[0112] In certain embodiments, the solid catalyst is used at an amount of about 20 wt % to about 60 wt %.
[0113] In certain embodiments, the solid catalyst is used at an amount of about 40 wt %.
[0114] In certain embodiments, the alkane is propane, the oxidizing agent is oxygen, the radical initiator is nitric oxide or nitrogen dioxide.
[0115] In certain embodiments, the alkene formed is ethylene or propylene.
[0116] In certain embodiments, the oxygenate formed is propylene oxide.
[0117] In certain embodiments, the reactor is a straight quartz tube, a U-shaped quartz tube, a straight stainless steel tube, or a U-shaped stainless steel tube.
[0118] In certain embodiments, the reactor is a U-shaped quartz tube.
[0119] In another aspect, provided are gas-phase coupling processes for converting a hydrocarbon feedstock to an effluent stream, comprising:
flowing a feed gas comprising a hydrocarbon feedstock, an oxidizing agent, and a radical initiator through a heated reaction zone within a reactor;
wherein:
the hydrocarbon feedstock comprises an oxygenate, and a C.sub.1-C.sub.6 alkane or a C.sub.2-C.sub.6 alkene;
the effluent stream comprises a C.sub.7-C.sub.20 alkane or a C.sub.7-C.sub.20 alkene or both;
the heated reaction zone has a temperature of about 363 to about 1000 K; and
the heated reaction zone is a space or a combination of a space and an inert solid surface, whereby the effluent stream is produced.
[0120] In yet another aspect, provided are gas-phase coupling processes for converting an alkene and an oxygenate to a longer carbon-chain alkene or a longer carbon-chain alkane, comprising:
flowing a feed gas through a heated reaction zone within a reactor, wherein the feed gas comprises an alkene, an oxygenate, an oxidizing agent, and a radical initiator,
wherein:
the heated reaction zone has a temperature of about 363 to about 1000 K; and
the heated reaction zone is a space or a combination of a space and an inert solid surface.
[0121] In certain embodiments, the alkene in the feed gas comprises a C.sub.2-20 alkene.
[0122] In certain embodiments, the alkene in the feed gas comprises a C.sub.2-6 alkene.
[0123] In certain embodiments, the alkene in the feed gas comprises ethylene.
[0124] In certain embodiments, the oxygenate in the feed gas comprises C.sub.1-6 alcohol.
[0125] In certain embodiments, the oxygenate in the feed gas comprises methanol, ethanol or isopropanol.
[0126] In certain embodiments, the oxidizing agent is oxygen.
[0127] In certain embodiments, the oxygen is present at about 3 kPa to about 50 kPa in the feed gas.
[0128] In certain embodiments, the radical initiator is nitric oxide present at about 1 to about 500 ppm in the feed gas.
[0129] In certain embodiments, the feed gas further includes an inert diluent.
[0130] In certain embodiments, the inert diluent is helium, nitrogen, carbon dioxide, or carbon monoxide.
[0131] In certain embodiments, the inert diluent is helium or nitrogen.
[0132] In certain embodiments, the feed gas further comprises water vapor.
[0133] In certain embodiments, the process is performed at about 1 to about 5 atmospheric pressure.
[0134] In certain embodiments, the process is performed at about 1 atmospheric pressure.
[0135] In certain embodiments, the process is performed at a temperature from 363-873 K.
[0136] In certain embodiments, the process is performed in the absence of a solid catalyst.
[0137] In certain embodiments, the lower alkene is propene or ethylene, the oxygenate is methanol, the oxidizing agent is oxygen, and the radical initiator is nitric oxide or nitrogen dioxide.
[0138] In certain embodiments, the reactor is a straight quartz tube, a U-shaped quartz tube, a straight stainless steel tube, or a U-shaped stainless steel tube.
[0139] In certain embodiments, the reactor is a U-shaped quartz tube.
Definitions
[0140] Definitions of specific functional groups and chemical terms are described in more detail below. The chemical elements are identified in accordance with the Periodic Table of the Elements, CAS version, Handbook of Chemistry and Physics, 75.sup.th Ed., inside cover, and specific functional groups are generally defined as described therein. Additionally, general principles of organic chemistry, as well as specific functional moieties and reactivity, are described in Thomas Sorrell, Organic Chemistry, University Science Books, Sausalito, 1999; Smith and March, March's Advanced Organic Chemistry, 5.sup.th Edition, John Wiley & Sons, Inc., New York, 2001; Larock, Comprehensive Organic Transformations, VCH Publishers, Inc., New York, 1989; and Carruthers, Some Modern Methods of Organic Synthesis, 3.sup.rd Edition, Cambridge University Press, Cambridge, 1987.
[0141] When a range of values is listed, it is intended to encompass each value and sub-range within the range. For example, “C.sub.1-6 alkyl” is intended to encompass, C.sub.1, C.sub.2, C.sub.3, C.sub.4, C.sub.5, C.sub.6, C.sub.1-6, C.sub.1-5, C.sub.1-4, C.sub.1-3, C.sub.1-2, C.sub.2-6, C.sub.2-5, C.sub.2-4, C.sub.2-3, C.sub.3-6, C.sub.3-5, C.sub.3-4, C.sub.4-6, C.sub.4-5, and C.sub.5-6 alkyl.
[0142] The following terms are intended to have the meanings presented therewith below and are useful in understanding the description and intended scope of the present invention. When describing the invention, which may include compounds, pharmaceutical compositions containing such compounds and methods of using such compounds and compositions, the following terms, if present, have the following meanings unless otherwise indicated. It should also be understood that when described herein any of the moieties defined forth below may be substituted with a variety of substituents, and that, the respective definitions are intended to include such substituted moieties within their scope as set out below. Unless otherwise stated, the term “substituted” is to be defined as set out below. It should be further understood that the terms “groups” and “radicals” can be considered interchangeable when used herein. The articles “a” and “an” may be used herein to refer to one or to more than one (i.e. at least one) of the grammatical objects of the article. By way of example “an analogue” means one analogue or more than one analogue.
[0143] “Alkyl” refers to a radical of a straight-chain or branched saturated hydrocarbon group having from 1 to 20 carbon atoms (“C.sub.1-20 alkyl”). In some embodiments, an alkyl group has 1 to 12 carbon atoms (“C.sub.1-12 alkyl”). In some embodiments, an alkyl group has 1 to 10 carbon atoms (“C.sub.1-10 alkyl”). In some embodiments, an alkyl group has 1 to 9 carbon atoms (“C.sub.1-9 alkyl”). In some embodiments, an alkyl group has 1 to 8 carbon atoms (“C.sub.1-8 alkyl”). In some embodiments, an alkyl group has 1 to 7 carbon atoms (“C.sub.1-7 alkyl”). In some embodiments, an alkyl group has 1 to 6 carbon atoms (“C.sub.1-6 alkyl”, also referred to herein as “lower alkyl”). In some embodiments, an alkyl group has 1 to 5 carbon atoms (“C.sub.1-5 alkyl”). In some embodiments, an alkyl group has 1 to 4 carbon atoms (“C.sub.1-4 alkyl”). In some embodiments, an alkyl group has 1 to 3 carbon atoms (“C.sub.1-3 alkyl”). In some embodiments, an alkyl group has 1 to 2 carbon atoms (“C.sub.1-2 alkyl”). In some embodiments, an alkyl group has 1 carbon atom (“C.sub.1 alkyl”). In some embodiments, an alkyl group has 2 to 6 carbon atoms (“C.sub.2-6 alkyl”). Examples of C.sub.1-6 alkyl groups include methyl (C.sub.1), ethyl (C.sub.2), n-propyl (C.sub.3), isopropyl (C.sub.3), n-butyl (C.sub.4), ten-butyl (C.sub.4), sec-butyl (C.sub.4), isobutyl (C.sub.4), n-pentyl (C.sub.5), 3-pentanyl (C.sub.5), amyl (C.sub.5), neopentyl (C.sub.5), 3-methyl-2-butanyl (C.sub.5), tertiary amyl (C.sub.5), and n-hexyl (C.sub.6). Additional examples of alkyl groups include w-heptyl (C.sub.7), n-octyl (C.sub.8) and the like. Unless otherwise specified, each instance of an alkyl group is independently optionally substituted, i.e., unsubstituted (an “unsubstituted alkyl”) or substituted (a “substituted alkyl”) with one or more substituents; e.g., for instance from 1 to 5 substituents, 1 to 3 substituents, or 1 substituent. In certain embodiments, the alkyl group is unsubstituted C.sub.1-10 alkyl (e.g., —CH.sub.3). In certain embodiments, the alkyl group is substituted C.sub.1-10 alkyl. Common alkyl abbreviations include Me (—CH.sub.3), Et (—CH.sub.2CH.sub.3), i-Pr (—CH(CH.sub.3).sub.2), n-Pr (—CH.sub.2CH.sub.2CH.sub.3), n-Bu (—CH.sub.2CH.sub.2CH.sub.2CH.sub.3), or i-Bu (—CH.sub.2CH(CH.sub.3).sub.2).
[0144] “Alkylene” refers to an alkyl group wherein two hydrogens are removed to provide a divalent radical, and which may be substituted or unsubstituted. Unsubstituted alkylene groups include, but are not limited to, methylene (—CH.sub.2—), ethylene (—CH.sub.2CH.sub.2—), propylene (—CH.sub.2CH.sub.2CH.sub.2—), butylene (—CH.sub.2CH.sub.2CH.sub.2CH.sub.2—), pentylene (—CH.sub.2CH.sub.2CH.sub.2CH.sub.2CH.sub.2—), hexylene (—CH.sub.2CH.sub.2CH.sub.2CH.sub.2CH.sub.2CH.sub.2—), and the like. Exemplary substituted alkylene groups, e.g., substituted with one or more alkyl (methyl) groups, include hut are not limited to, substituted methylene (—CH(CH.sub.3)—, (—C(CH.sub.3).sub.2—), substituted ethylene (—CH(CH.sub.3)CH.sub.2—, —CH.sub.2CH(CH.sub.3)—, —C(CH.sub.3).sub.2CH.sub.2—, —CH.sub.2C(CH.sub.3).sub.2—), substituted propylene (—CH(CH.sub.3)CH.sub.2CH.sub.2—, —CH.sub.2CH(CH.sub.3)CH.sub.2—, —CH.sub.2CH.sub.2CH(CH.sub.3)—, —C(CH.sub.3).sub.2CH.sub.2CH.sub.2—, —CH.sub.2C(CH3).sub.2CH.sub.2—, —CH.sub.2CH.sub.2C(CH.sub.3).sub.2—), and the like.
[0145] “Alkenyl” refers to a radical of a straight-chain or branched hydrocarbon group having from 2 to 20 carbon atoms, one or more carbon-carbon double bonds (e.g., 1, 2, 3, or 4 carbon-carbon double bonds), and optionally one or more carbon-carbon triple bonds (e.g., 1, 2, 3, or 4 carbon-carbon triple bonds) (“C.sub.2-20 alkenyl”). In certain embodiments, alkenyl does not contain any triple bonds. In some embodiments, an alkenyl group has 2 to 10 carbon atoms (“C.sub.2-10 alkenyl”). In some embodiments, an alkenyl group has 2 to 9 carbon atoms (“C.sub.2-9 alkenyl”). In some embodiments, an alkenyl group has 2 to 8 carbon atoms (“C.sub.2-8 alkenyl”). In some embodiments, an alkenyl group has 2 to 7 carbon atoms (“C.sub.2-7 alkenyl”). In some embodiments, an alkenyl group has 2 to 6 carbon atoms (“C.sub.2-6 alkenyl”). In some embodiments, an alkenyl group has 2 to 5 carbon atoms (“C.sub.2-5 alkenyl”). In some embodiments, an alkenyl group has 2 to 4 carbon atoms (“C.sub.2-4 alkenyl”). In some embodiments, an alkenyl group has 2 to 3 carbon atoms (“C.sub.2-3 alkenyl”). In some embodiments, an alkenyl group has 2 carbon atoms (“C.sub.2 alkenyl”). The one or more carbon-carbon double bonds can be internal (such as in 2-butenyl) or terminal (such as in 1-butenyl). Examples of C.sub.2-4 alkenyl groups include ethenyl (C.sub.2), 1-propenyl (C.sub.3), 2-propenyl (C.sub.3), 1-butenyl (C.sub.4), 2-butenyl (C.sub.4), butadienyl (C.sub.4), and the like. Examples of C.sub.2-6 alkenyl groups include the aforementioned C.sub.2-4 alkenyl groups as well as pentenyl (C.sub.5), pentadienyl (C.sub.5), hexenyl (C.sub.6), and the like. Additional examples of alkenyl include heptenyl (C.sub.7), octenyl (C.sub.8), octatrienyl (C.sub.8), and the like. Unless otherwise specified, each instance of an alkenyl group is independently optionally substituted, i.e., unsubstituted (an “unsubstituted alkenyl”) or substituted (a “substituted alkenyl”) with one or more substituents e.g., for instance front 1 to 5 substituents, 1 to 3 substituents, or 1 substituent. In certain embodiments, the alkenyl group is unsubstituted C.sub.2-10 alkenyl. In certain embodiments, the alkenyl group is substituted C.sub.2-10 alkenyl.
[0146] “Alkenylene” refers to an alkenyl group wherein two hydrogens are removed to provide a divalent radical, and which may be substituted or unsubstituted. Exemplary unsubstituted divalent alkenylene groups include, but are not limited to, ethenylene (—CH═CH—) and propenylene (e.g., —CH═CHCH.sub.2—, —CH.sub.2—CH═CH—). Exemplary substituted alkenylene groups, e.g., substituted with one or more alkyl (methyl) groups, include but are not limited to, substituted ethylene (—C(CH.sub.3)═CH—, —CH═C(CH.sub.3)—), substituted propylene (e.g., —C(CH.sub.3)═CHCH.sub.2—, —CH═C(CH.sub.3)CH.sub.2—, —CH═CHCH(CH.sub.3)—, —CH═CHC(CH.sub.3).sub.2—, —CH(CH.sub.3)—CH═CH—, —C(CH.sub.3).sub.2—CH═CH—, —CH.sub.2—C(CH.sub.3)═CH—, —CH.sub.2—CH═(CH.sub.3)—), and the like.
[0147] “Alkynyl” refers to a radical of a straight-chain or branched hydrocarbon group having from 2 to 20 carbon atoms, one or more carbon-carbon triple bonds (e.g., 1, 2, 3, or 4 carbon-carbon tuple bonds), and optionally one or more carbon-carbon double bonds (e.g., 1, 2, 3, or 4 carbon-carbon double bonds) (“C.sub.2-20 alkynyl”). In certain embodiments, alkynyl does not contain any double bonds. In some embodiments, an alkynyl group has 2 to 10 carbon atoms (“C.sub.2-10 alkynyl”). In some embodiments, an alkynyl group has 2 to 9 carbon atoms (“C.sub.2-9 alkynyl”). In some embodiments, an alkynyl group has 2 to 8 carbon atoms (“C.sub.2-8 alkynyl”). In some embodiments, an alkynyl group has 2 to 7 carbon atoms (“C.sub.2-7 alkynyl”). In some embodiments, an alkynyl group has 2 to 6 carbon atoms (“C.sub.2-6 alkynyl”). In some embodiments, an alkynyl group has 2 to 5 carbon atoms (“C.sub.2-5 alkynyl”). In some embodiments, an alkynyl group has 2 to 4 carbon atoms (“C.sub.2-4 alkynyl”). In some embodiments, an alkynyl group has 2 to 3 carbon atoms (“C.sub.2-3 alkynyl”). In some embodiments, an alkynyl group has 2 carbon atoms (“C.sub.2 alkynyl”). The one or more carbon-carbon triple bonds can be internal (such as in 2-butynyl) or terminal (such as in 1-butynyl). Examples of C.sub.2-4 alkynyl groups include, without limitation, ethynyl (C.sub.2), 1-propynyl (C.sub.3), 2-propynyl (C.sub.3), 1-butynyl (C.sub.4), 2-butynyl (C.sub.4), and the like. Examples of C.sub.2-6 alkenyl groups include the aforementioned C.sub.2-4 alkynyl groups as well as pentynyl (C.sub.5), hexynyl (C.sub.6), and the like. Additional examples of alkynyl include heptynyl (C.sub.7), octynyl (C.sub.8), and the like. Unless otherwise specified, each instance of an alkynyl group is independently optionally substituted, i.e., unsubstituted (an “unsubstituted alkynyl”) or substituted (a “substituted alkynyl”) with one or more substituents; e.g., for instance from 1 to 5 substituents, 1 to 3 substituents, or 1 substituent. In certain embodiments, the alkynyl group is unsubstituted C.sub.2-10 alkynyl. In certain embodiments, the alkynyl group is substituted C.sub.2-10 alkynyl.
[0148] “Alkynylene” refers to a linear alkynyl group wherein two hydrogens are removed to provide a divalent radical, and which may be substituted or unsubstituted. Exemplary divalent alkynylene groups include, but are not limited to, substituted or unsubstituted ethynylene, substituted or unsubstituted propynylene, and the like.
[0149] The term “heteroalkyl,” as used herein, refers to an alkyl group, as defined herein, which further comprises 1 or more (e.g., 1, 2, 3, or 4) heteroatoms (e.g., oxygen, sulfur, nitrogen, boron, silicon, phosphorus) within the parent chain, wherein the one or more heteroatoms is inserted between adjacent carbon atoms within the parent carbon chain and/or one or more heteroatoms is inserted between a carbon atom and the parent molecule, i.e., between the point of attachment. In certain embodiments, a heteroalkyl group refers to a saturated group having from 1 to 10 carbon atoms and 1, 2, 3, or 4 heteroatoms (“heteroC.sub.1-10 alkyl”). In some embodiments, a heteroalkyl group is a saturated group having 1 to 9 carbon atoms and 1, 2, 3, or 4 heteroatoms (“heteroC.sub.1-9 alkyl”). In some embodiments, a heteroalkyl group is a saturated group having 1 to 8 carbon atoms and 1, 2, 3, or 4 heteroatoms (“heteroC.sub.1-8 alkyl”). In some embodiments, a heteroalkyl group is a saturated group having 1 to 7 carbon atoms and 1, 2, 3, or 4 heteroatoms (“heteroC.sub.1-7 alkyl”). In some embodiments, a heteroalkyl group is a group having 1 to 6 carbon atoms and 1, 2, or 3 heteroatoms (“heteroC.sub.1-6 alkyl”). In some embodiments, a heteroalkyl group is a saturated group having 1 to 5 carbon atoms and 1 or 2 heteroatoms (“heteroC.sub.1-5 alkyl”). In some embodiments, a heteroalkyl group is a saturated group having 1 to 4 carbon atoms and/or 2 heteroatoms (“heteroC.sub.1-4 alkyl”). In some embodiments, a heteroalkyl group is a saturated group having 1 to 3 carbon atoms and 1 heteroatom (“heteroC.sub.1-3 alkyl”). In some embodiments, a heteroalkyl group is a saturated group having 1 to 2 carbon atoms and 1 heteroatom (“heteroC.sub.1-2 alkyl”). In some embodiments, a heteroalkyl group is a saturated group having 1 carbon atom and 1 heteroatom (“heteroC.sub.1 alkyl”). In some embodiments, a heteroalkyl group is a saturated group having 2 to 6 carbon atoms and 1 or 2 heteroatoms (“heteroC.sub.2-6 alkyl”). Unless otherwise specified, each instance of a heteroalkyl group Is independently unsubstituted (an “unsubstituted heteroalkyl”) or substituted (a “substituted heteroalkyl”) with one or more substituents. In certain embodiments, the heteroalkyl group is an unsubstituted heteroC.sub.1-10 alkyl. In certain embodiments, the heteroalkyl group is a substituted heteroC.sub.1-10 alkyl.
[0150] The term “heteroalkenyl,” as used herein, refers to an alkenyl group, as defined herein, which further comprises one or more (e.g., 1, 2, 3, or 4) heteroatoms (e.g., oxygen, sulfur, nitrogen, boron, silicon, phosphorus) wherein the one or more heteroatoms is inserted between adjacent carbon atoms within the parent carbon chain and/or one or more heteroatoms is inserted between a carbon atom and the parent molecule, i.e., between the point of attachment. In certain embodiments, a heteroalkenyl group refers to a group having from 2 to 10 carbon atoms, at least one double bond, and 1, 2, 3, or 4 heteroatoms (“heteroC.sub.2-10 alkenyl”). In some embodiments, a heteroalkenyl group has 2 to 9 carbon atoms at least one double bond, and 1, 2, 3, or 4 heteroatoms (“heteroC.sub.2-9 alkenyl”). In some embodiments, a heteroalkenyl group has 2 to 8 carbon atoms, at least one double bond, and 1, 2, 3, or 4 heteroatoms (“heteroC.sub.2-8 alkenyl”). In some embodiments, a heteroalkenyl group has 2 to 7 carbon atoms, at least one double bond, and 1, 2, 3, or 4 heteroatoms (“heteroC.sub.2-7 alkenyl”). In some embodiments, a heteroalkenyl group has 2 to 6 carbon atoms, at least one double bond, and 1, 2, or 3 heteroatoms (“heteroC.sub.2-6 alkenyl”). In some embodiments, a heteroalkenyl group has 2 to 5 carbon atoms, at least one double bond, and 1 or 2 heteroatoms (“heteroC.sub.2-5 alkenyl”). In some embodiments, a heteroalkenyl group has 2 to 4 carbon atoms, at least one double bond, and 1 or 2 heteroatoms (“heteroC.sub.2-4 alkenyl”). In some embodiments, a heteroalkenyl group has 2 to 3 carbon atoms, at least one double bond, and 1 heteroatom (“heteroC.sub.2-3 alkenyl”). In some embodiments, a heteroalkenyl group has 2 to 6 carbon atoms, at least one double bond, and 1 or 2 heteroatoms (“heteroC.sub.2-6 alkenyl”). Unless otherwise specified, each instance of a heteroalkenyl group is independently unsubstituted (an “unsubstituted heteroalkenyl”) or substituted (a “substituted heteroalkenyl”) with one or more substituents. In certain embodiments, the heteroalkenyl group is an unsubstituted heteroC.sub.2-10 alkenyl. In certain embodiments, the heteroalkenyl group is a substituted heteroC.sub.2-10 alkenyl.
[0151] The term “heteroalkynyl,” as used herein, refers to an alkynyl group, as defined herein, which further comprises one or more (e.g., 1, 2, 3, or 4) heteroatoms (e.g., oxygen, sulfur, nitrogen, boron, silicon, phosphorus) wherein the one or more heteroatoms is inserted between adjacent carbon atoms within the parent carbon chain and/or one or more heteroatoms is inserted between a carbon atom and the parent molecule, i.e., between the point of attachment. In certain embodiments, a heteroalkynyl group refers to a group having from 2 to 10 carbon atoms, at least one triple bond, and 1, 2, 3, or 4 heteroatoms (“heteroC.sub.2-10 alkynyl”). In some embodiments, a heteroalkynyl group has 2 to 9 carbon atoms, at least one triple bond, and 1, 2, 3, or 4 heteroatoms (“heteroC.sub.2-9 alkynyl”). In some embodiments, a heteroalkynyl group has 2 to 8 carbon atoms, at least one triple bond, and 1, 2, 3, or 4 heteroatoms (“heteroC.sub.2-8 alkynyl”). In some embodiments, a heteroalkynyl group has 2 to 7 carbon atoms, at least one triple bond, and 1, 2, 3, or 4 heteroatoms (“heteroC.sub.2-7 alkynyl”). In some embodiments, a heteroalkynyl group has 2 to 6 carbon atoms, at least one triple bond, and 1, 2, or 3 heteroatoms (“heteroC.sub.2-6 alkynyl”). In some embodiments, a heteroalkynyl group has 2 to 5 carbon atoms, at least one triple bond, and 1 or 2 heteroatoms (“heteroC.sub.2-5 alkynyl”). In some embodiments, a heteroalkynyl group has 2 to 4 carbon atoms, at least one triple bond, and 1 or 2 heteroatoms (“heteroC.sub.2-4 alkynyl”). In some embodiments, a heteroalkynyl group has 2 to 3 carbon atoms, at least one triple bond, and 1 heteroatom (“heteroC.sub.2-3 alkynyl”). In some embodiments, a heteroalkynyl group has 2 to 6 carbon atoms, at least one triple bond, and 1 or 2 heteroatoms (“heteroC.sub.2-6 alkynyl”). Unless otherwise specified, each instance of a heteroalkynyl group is independently unsubstituted (an “unsubstituted heteroalkynyl”) or substituted (a “substituted heteroalkynyl”) with one or more substituents. In certain embodiments, the heteroalkynyl group is an unsubstituted heteroC.sub.2-10 alkynyl. In certain embodiments, the heteroalkynyl group is a substituted heteroC.sub.2-10 alkynyl.
[0152] As used herein, “alkylene,” “alkenylene,” “alkynylene,” “heteroalkylene,” “heteroalkenylene,” and “heteroalkynylene,” refer to a divalent radical of an alkyl, alkenyl, alkynyl group, heteroalkyl, heteroalkenyl, and heteroalkynyl group respectively. When a range or number of carbons is provided for a particular “alkylene,” “alkenylene,” “alkynylene,” “heteroalkylene,” “heteroalkenylene,” or “heteroalkynylene,” group, it is understood that the range or number refers to the range or number of carbons in the linear carbon divalent chain. “Alkylene,” “alkenylene,” “alkynylene,” “heteroalkylene,” “heteroalkenylene,” and “heteroalkynylene” groups may be substituted or unsubstituted with one or more substituents as described herein.
[0153] “Aryl” refers to a radical of a monocyclic or polycyclic (e.g., bicyclic or tricyclic) 4n+2 aromatic ring system (e.g., having 6, 10, or 14π electrons shared in a cyclic array) having 6-14 ring carbon atoms and zero heteroatoms provided in the aromatic ring system (“C.sub.6-14 aryl”). In some embodiments, an aryl group has six ring carbon atoms (“C.sub.6 aryl”; e.g., phenyl). In some embodiments, an aryl group has ten ring carbon atoms (“C.sub.10 aryl”; e.g., naphthyl such as 1-naphthyl and 2-naphthyl). In some embodiments, an aryl group has fourteen ring carbon atoms (“C.sub.14 aryl”; e.g., anthracyl). “Aryl” also includes ring systems wherein the aryl ring, as defined above, is fused with one or more carbocyclyl or heterocyclyl groups wherein the radical or point of attachment is on the aryl ring, and in such instances, the number of carbon atoms continue to designate the number of carbon atoms in the aryl ring system. Typical aryl groups include, but are not limited to, groups derived from aceanthrylene, acenaphthylene, acephenanthrylene, anthracene, azulene, benzene, chrysene, coronene, fluoranthene, fluorene, hexacene, hexaphene, hexalene, as-indacene, s-indacene, indane, indene, naphthalene, octacene, octaphene, octalene, ovalene, penta-2,4-diene, pentacene, pentalene, pentaphene, perylene, phenalene, phenanthrene, picene, pleiadene, pyrene, pyranthrene, rubicene, triphenylene, and trinaphthalene. Particularly aryl groups include phenyl, naphthyl, indenyl, and tetrahydronaphthyl. Unless otherwise specified, each instance of an aryl group is independently optionally substituted, i.e., unsubstituted (an “unsubstituted aryl”) or substituted (a “substituted aryl”) with one or more substituents. In certain embodiments, the and group is unsubstituted C.sub.6-14 aryl. In certain embodiments, the aryl group is substituted C.sub.6-14 aryl.
[0154] In certain embodiments, an aryl group substituted with one or more of groups selected from halo, C.sub.1-8 alkyl, C.sub.1-8 haloalkyl, cyano, hydroxy, C.sub.1-8 alkoxy, and amino.
[0155] Examples of representative substituted aryls include the following
##STR00001##
[0156] wherein one of R.sup.56 and R.sup.57 may be hydrogen and at least one of R.sup.56 and R.sup.57 is each independently selected from C.sub.1-8 alkyl, C.sub.1-8 haloalkyl, 4- to 10-membered heterocyclyl, alkanoyl, C.sub.1-8 alkoxy, heteroaryl oxy, alkyl amino, arylamino, heteroaryl amino, NR.sup.58COR.sup.59, NR.sup.58SOR.sup.59NR.sup.58SO.sub.2R.sup.59, COOalkyl, COGaryl, CONR.sup.58R.sup.59, CONR.sup.58OR.sup.59, NR.sup.58R.sup.59, SO.sub.2NR.sup.58R.sup.59, S-alkyl, SOalkyl, SOralkyl, Saryl, SOaryl, SO.sub.2aryl; or R.sup.56 and R.sup.57 may be joined to form a cyclic ring (saturated or unsaturated) from 5 to 8 atoms, optionally containing one or more heteroatoms selected from the group N, O, or S. R.sup.60 and R.sup.61 are independently hydrogen, C.sub.1-8 alkyl, C.sub.1-4 haloalkyl, C.sub.3-10 carbocyclyl, 4- to 10-membered heterocyclyl, C.sub.6-10 aryl, substituted C.sub.6-10 aryl, 5-10 membered heteroaryl, or substituted 5- to 10-membered heteroaryl.
[0157] Other representative aryl groups having a fused heterocycyl group include the following:
##STR00002##
[0158] wherein each W is selected from C(R.sup.66).sub.2, NR.sup.66, O, and S; and each Y is selected from carbonyl, NR.sup.66, O and S; and R.sup.66 is independently hydrogen, C.sub.1-8 alkyl, C.sub.3-10 carbocyclyl, 4- to 10-membered heterocycyl, C.sub.6-10 aryl, and 5- to 10-membered heteroaryl.
[0159] “Fused aryl” refers to an aryl having two of its ring carbon in common with a second aryl or heteroaryl ring or with a carbocyclyl or heterocycyl ring.
[0160] “Aralkyl” is a subset of alkyl and aryl, as defined herein, and refers to an optionally substituted alkyl group substituted by an optionally substituted aryl group.
[0161] “Heteroaryl” refers to a radical of a 5- to 10-membered monocyclic or bicyclic 4n+2 aromatic ring system (e.g., having 6 or 10 π electrons shared in a cyclic array) having ring carbon atoms and 1-4 ring heteroatoms provided in the aromatic ring system, wherein each heteroatom is independently selected from nitrogen, oxygen and sulfur (“5- to 10-membered heteroaryl”). In heteroaryl groups that contain one or more nitrogen atoms, the point of attachment can be a carbon or nitrogen atom, as valency permits. Heteroaryl bicyclic ring systems can include one or more heteroatoms in one or both rings. “Heteroaryl” includes ring systems wherein the heteroaryl ring, as defined above, is fused with, one or more carbocyclyl or heterocycyl groups wherein the point of attachment is on the heteroaryl ring, and in such instances, the number of ring members continue to designate the number of ring members in the heteroaryl ring system. “Heteroaryl” also includes ring systems wherein the heteroaryl ring, as defined, above, is fused with one or more aryl groups wherein the point of attachment is either on the aryl or heteroaryl ring, and in such instances, the number of ring members designates the number of ring members in the fused (aryl/heteroaryl) ring system. Bicyclic heteroaryl groups wherein one ring does not contain a heteroatom (e.g., indolyl, quinolinyl, carbazolyl, and the like) the point of attachment can be on either ring, i.e., either the ring bearing a heteroatom (e.g., 2-indolyl) or the ring that does not contain a heteroatom (e.g., 5-indolyl).
[0162] In some embodiments, a heteroaryl group is a 5- to 10-membered aromatic ring system having ring carbon atoms and 1-4 ring heteroatoms provided in the aromatic ring system, wherein each heteroatom is independently selected from nitrogen, oxygen, and sulfur (“5- to 10-membered heteroaryl”). In some embodiments, a heteroaryl group is a 5- to 8-membered aromatic ring system having ring carbon atoms and 1-4 ring heteroatoms provided in the aromatic ring system, wherein each heteroatom is independently selected from nitrogen, oxygen, and sulfur (“5- to 8-membered heteroaryl”). In some embodiments, a heteroaryl group is a 5- to 6-membered aromatic ring system having ring carbon atoms and 1-4 ring heteroatoms provided in the aromatic ring system, wherein each heteroatom is independently selected from nitrogen, oxygen, and sulfur (“5- to 6-membered heteroaryl”). In some embodiments, the 5-6 membered heteroaryl has 1-3 ring heteroatoms selected from nitrogen, oxygen, and sulfur. In some embodiments, the 5- to 6-membered heteroaryl has 1-2 ring heteroatoms selected from nitrogen, oxygen, and sulfur. In some embodiments, the 5- to 6-membered heteroaryl has 1 ring heteroatom selected from nitrogen, oxygen, and sulfur. Unless otherwise specified, each instance of a heteroaryl group is independently optionally substituted, i.e., unsubstituted (an “unsubstituted heteroaryl”) or substituted (a “substituted heteroaryl”) with one or more substituents. In certain embodiments, the heteroaryl group is unsubstituted 5- to 14-membered heteroaryl. In certain embodiments, the heteroaryl group is substituted 5- to 14-membered heteroaryl.
[0163] Exemplary 5-membered heteroaryl groups containing one heteroatom include, without limitation, pyrroyl, furanyl and thiophenyl. Exemplary 5-membered heteroaryl groups containing two heteroatoms include, without limitation, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, and isothiazolyl. Exemplary 5-membered heteroaryl groups containing three heteroatoms include, without limitation, triazolyl, oxadiazolyl, and thiadiazolyl. Exemplary 5-membered heteroaryl groups containing four heteroatoms include, without limitation, tetrazolyl. Exemplary membered heteroaryl groups containing one heteroatom include, without limitation, pyridinyl. Exemplary 6-membered heteroaryl groups containing two heteroatoms include, without limitation, pyridazinyl, pyrimidinyl, and pyrazinyl. Exemplary 6-membered heteroaryl groups containing three or four heteroatoms include, without limitation, triazinyl and tetrazinyl, respectively. Exemplary 7-membered heteroaryl groups containing one heteroatom include, without limitation, azepinyl, oxepinyl, and thiepinyl. Exemplary 5,6-bicyclic heteroaryl groups Include, without limitation, indolyl, isoindolyl, indazolyl, benzotriazolyl, benzothiophenyl, isobenzothiophenyl, benzofuranyl, benzoisofuranyl, benzimidazolyl, benzoxazolyl, benzisoxazolyl, benzoxadiazolyl, benzthiazolyl, benzisothiazolyl, benzthiadiazolyl, indolizinyl, and purinyl. Exemplary 6,6-bicyclic heteroaryl groups include, without limitation, naphthyridinyl, pteridinyl, quinolinyl, isoquinolinyl, cinnolinyl, quinoxalinyl, phthalazinyl, and quinazolinyl.
[0164] Examples of representative heteroaryls include the following:
##STR00003##
[0165] wherein each Y is selected from carbonyl, N, NR.sup.65, O, and S; and R.sup.65 is independently hydrogen, C.sub.1-8 alkyl, C.sub.3-10 carbocyclyl, 4-10 membered heterocyclyl, C.sub.6-10 aryl, and 5-10 membered heteroaryl.
[0166] “Heteroaralkyl” is a subset of alkyl and heteroaryl, as defined herein, and refers to an optionally substituted alkyl group substituted by an optionally substituted heteroaryl group.
[0167] “Carbocyclyl” or “carbocyclic” refers to a radical of a non-aromatic cyclic hydrocarbon group having from 3 to 10 ring carbon atoms (“C.sub.3-10 carbocyclyl”) and zero heteroatoms in the nonaromatic ring system. In some embodiments, a carbocyclyl group has 3 to 8 ring carbon atoms (“C.sub.3-8 carbocyclyl”). In some embodiments, a carbocyclyl group has 3 to 6 ring carbon atoms (“C.sub.3-6 carbocyclyl”). In some embodiments, a carbocyclyl group has 5 to 6 ring carbon atoms (“C.sub.5-6 carbocyclyl”). In some embodiments, a carbocyclyl group has 5 to 10 ring carbon atoms (“C.sub.5-10 carbocyclyl”). Exemplary C.sub.3-6 carbocyclyl groups include, without limitation, cyclopropyl (C.sub.3), cyclopropenyl (C.sub.3), cyclobutyl (C.sub.4), cyclobutenyl (C.sub.4), cyclopentyl (C.sub.5), cyclopentenyl (C.sub.5), cyclohexyl (C.sub.6), cyclohexenyl (C.sub.6), cyclohexadienyl (C.sub.6), and the like. Exemplary C.sub.3-5 carbocyclyl groups include, without limitation, the aforementioned C.sub.3-6 carbocyclyl groups as well as cycloheptyl (C.sub.7), cycloheptenyl (C.sub.7), cycloheptadienyl (C.sub.7), cycloheptatrienyl (C.sub.7), cyclooctyl (C.sub.8), cyclooctenyl (C.sub.8), bicyclo[2.2.1]heptanyl (C.sub.7), bicyclo[2.2.2]octanyl (C.sub.8), and the like. Exemplary C.sub.3-10 carbocyclyl groups include, without limitation, the aforementioned C.sub.3-8 carbocyclyl groups as well as cyclononyl (C.sub.9), cyclononenyl (C.sub.9), cyclodecyl (C.sub.10), cyclodecenyl (C.sub.10), octahydro-1H-indenyl (C.sub.9), decahydronaphthalenyl (C.sub.10), spiro[4.5]decanyl (C.sub.10), and the like. As the foregoing examples illustrate, in certain embodiments, the carbocyclyl group is either monocyclic (“monocyclic carbocyclyl”) or contain a fused, bridged or spiro ring system such as a bicyclic system (“bicyclic carbocyclyl”) and can be saturated or can be partially unsaturated. “Carbocyclyl” also includes ring systems wherein the carbocyclyl ring, as defined above, is fused with one or more and or heteroaryl groups wherein the point of attachment is on the carbocyclyl ring, and in such instances, the number of carbons continue to designate the number of carbons in the carbocyclic ring system. Unless otherwise specified, each instance of a carbocyclyl group is independently optionally substituted, i.e., unsubstituted (an “unsubstituted carbocyclyl”) or substituted (a “substituted carbocyclyl”) with one or more substituents. In certain embodiments, the carbocyclyl group is unsubstituted C.sub.3-10 carbocyclyl. In certain embodiments, the carbocyclyl group is a substituted C.sub.3-10 carbocyclyl.
[0168] In some embodiments, “carbocyclyl” is a monocyclic, saturated carbocyclyl group having from 3 to 10 ring carbon atoms (“C.sub.3-10 carbocyclyl”). In some embodiments, a carbocyclyl group has 3 to 8 ring carbon atoms (“C.sub.3-8 carbocyclyl”). In some embodiments, a carbocyclyl group has 3 to 6 ring carbon atoms (“C.sub.3-6 carbocyclyl”). In some embodiments, a carbocyclyl group has 5 to 6 ring carbon atoms (“C.sub.5-6 carbocyclyl”). In some embodiments, a carbocyclyl group has 5 to 10 ring carbon atoms (“C.sub.5-10 carbocyclyl”). Examples of C.sub.5-6 carbocyclyl groups include cyclopentyl (C.sub.5) and cyclohexyl (C.sub.5). Examples of C.sub.3-6 carbocyclyl groups include the aforementioned C.sub.5-6 carbocyclyl groups as well as cyclopropyl (C.sub.3) and cyclobutyl (C.sub.4). Examples of C.sub.3-8 carbocyclyl groups include the aforementioned C.sub.3-6 carbocyclyl groups as well as cycloheptyl (C.sub.7) and cyclooctyl (C.sub.8). Unless otherwise specified, each instance of a carbocyclyl group is independently unsubstituted (an “unsubstituted carbocyclyl”) or substituted (a “substituted carbocyclyl”) with one or more substituents. In certain embodiments, the carbocyclyl group is unsubstituted C.sub.3-10 carbocyclyl. In certain embodiments, the carbocyclyl group is substituted C.sub.3-10 carbocyclyl.
[0169] “Heterocyclyl” or “heterocyclic” refers to a radical of a 3- to 10-membered non-aromatic-ring system having ring carbon atoms and 1 to 4 ring heteroatoms, wherein each heteroatom is independently selected from nitrogen, oxygen, sulfur, boron, phosphorus, and silicon (“3- to 10-membered heterocyclyl”). In heterocyclyl groups that contain one or more nitrogen atoms, the point of attachment cart be a carbon or nitrogen atom, as valency permits. A heterocyclyl group can either be monocyclic (“monocyclic heterocyclyl”) or a fused, bridged or spiro ring system such as a bicyclic system (“bicyclic heterocyclyl”), and cart be saturated or can be partially unsaturated. Heterocyclyl bicyclic ring systems can include one or more heteroatoms in one or both rings. “Heterocyclyi” also includes ring systems wherein the heterocyclyl ring, as defined above, is fused with one or more carbocyclyl groups wherein the point of attachment is either on the carbocyclyl or heterocyclyl ring, or ring systems wherein the heterocyclyl ring, as defined above, is fused with one or more aryl or heteroaryl groups, wherein the point of attachment is on the heterocyclyl ring, and in such instances, the number of ring members continue to designate the number of ring members in the heterocyclyl ring system. Unless otherwise specified, each instance of heterocyclyl is independently optionally substituted, i.e., unsubstituted (an “unsubstituted heterocyclyl”) or substituted (a “substituted heterocyclyl”) with one or more substituents. In certain embodiments, the heterocyclyl group is unsubstituted 3- to 10-membered heterocyclyl. In certain embodiments, the heterocyclyl group is substituted 3- to 10-membered heterocyclyl.
[0170] In some embodiments, a heterocyclyl group is a 5- to 10-membered non-aromatic ring system having ring carbon atoms and 1-4 ring heteroatoms, wherein each heteroatom is independently selected from nitrogen, oxygen, sulfur, boron, phosphorus, and silicon (“5- to 10-membered heterocyclyl”). In some embodiments, a heterocyclyl group is a 5- to 8-membered non-aromatic ring system having ring carbon atoms and 1-4 ring heteroatoms, wherein each heteroatom is independently selected from nitrogen, oxygen, and sulfur (“5- to 8-membered heterocyclyl”). In some embodiments, a heterocyclyl group is a 5- to 6-membered non-aromatic ring system having ring carbon atoms and 1-4 ring heteroatoms, wherein each heteroatom is independently selected from nitrogen, oxygen, and sulfur (“5- to 6-membered heterocyclyl”). In some embodiments, the 5-6 membered heterocyclyl has 1-3 ring heteroatoms selected from nitrogen, oxygen, and sulfur. In some embodiments, the 5- to 6-membered heterocyclyl has 1-2 ring heteroatoms selected from nitrogen, oxygen, and sulfur, fir some embodiments, the 5- to 6-membered heterocyclyl has one ring heteroatom selected from nitrogen, oxygen, and sulfur.
[0171] Exemplary 3-membered heterocyclyl groups containing one heteroatom include, without limitation, aziridinyl, oxiranyl, thiorenyl. Exemplary 4-membered heterocyclyl groups containing one heteroatom include, without limitation, azetidinyl, oxetanyl and thietanyl. Exemplary 5 membered heterocyclyl groups containing one heteroatom include, without limitation, tetrahydrofuranyl, dihydrofuranyl, tetrahydrothiophenyl, dihydrothiophenyl, pyrrolidinyl, dihydropyrrolyl and pyrrolyl-2,5-dione. Exemplary 5-membered heterocyclyl groups containing two heteroatoms include, without limitation, dioxolanyl, oxasulfuranyl, disulfuranyl, and oxazolidin-2-one. Exemplary 5-membered heterocyclyl groups containing three heteroatoms include, without limitation, triazolinyl, oxadiazolinyl, and thiadiazolinyl. Exemplary 6-membered heterocyclyl groups containing one heteroatom include, without limitation, piperidinyl, tetrahydropyranyl, dihydropyridinyl, and thianyl. Exemplary 6-membered heterocyclyl groups containing two heteroatoms include, without limitation, piperazinyl, morpholinyl, dithianyl, dioxanyl. Exemplary 6-membered heterocyclyl groups containing two heteroatoms include, without limitation, triazinanyl. Exemplary 7-membered heterocyclyl groups containing one heteroatom include, without limitation, azepanyl, oxepanyl and thiepanyl. Exemplary 8-membered heterocyclyl groups containing one heteroatom include, without limitation, azocanyl, oxecanyl and thiocanyl. Exemplary 5-membered heterocyclyl groups fused to a C.sub.6 aryl ring (also referred to herein as a 5,6-bicyclic heterocyclic ring) include, without limitation, indolinyl, isoindolinyl, dihydrobenzofuranyl, dihydrobenzothienyl, benzoxazolinonyl, and the like. Exemplary 6-membered heterocyclyl groups fused to an aryl ring (also referred to herein as a 6,6-bicyclic heterocyclic ring) include, without limitation, tetrahydroquinolinyl, tetrahydroisoquinolinyl, and the like.
[0172] Particular examples of heterocyclyl groups are shown in the following illustrative examples:
##STR00004##
[0173] wherein each W is selected from CR.sup.67, C(R.sup.67).sub.2, NR.sup.67, O, and S; and each Y is selected from NR.sup.67, O, and S; and R.sup.67 is independently hydrogen, C.sub.1-8 alkyl, C.sub.3-10 carbocyclyl, 4- to 10-membered heterocyclyl, C.sub.6-10 aryl, 5- to 10-membered heteroaryl. These heterocyclyl rings may be optionally substituted with one or more groups selected from the group consisting of acyl acylamino, acyloxy, alkoxy, alkoxycarbonyl, alkoxycarbonylamino, amino, substituted amino, aminocarbonyl (carbamoyl or amido), aminocarbonylamino, aminosulfonyl, sulfonylamino, aryl, aryloxy, azido, carboxyl, cyano, carbocyclyl, halogen, hydroxy, keto, nitro, thiol, —S-alkyl, —S-aryl, —S(O)-alkyl, —S(O)-aryl, —S(O).sub.2-alkyl, and —S(O).sub.2-aryl. Substituting groups include carbonyl or thiocarbonyl which provide, for example, lactam and urea derivatives.
[0174] “Hetero” when used to describe a compound or a group present on a compound means that one or more carbon atoms in the compound or group have been replaced by a nitrogen, oxygen or sulfur heteroatom. Hetero may be applied to any of the hydrocarbyl groups described above such as alkyl, e.g., heteroalkyl, carbocyclyl, e.g., heterocyclyl, aryl, e.g., heteroaryl, cycloalkenyl, e.g., cycloheteroalkenyl, and the like having from 1 to 5, and particularly from 1 to 3 heteroatoms.
[0175] “Acyl” refers to a radical —C(O)R.sup.20, where R.sup.20 is hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted carbocyclyl, substituted or unsubstituted heterocyclyl, substituted or unsubstituted aryl, or substituted or unsubstituted heteroaryl, as defined herein. “Alkanoyl” is an acyl group wherein R.sup.20 is a group other than hydrogen. Representative acyl groups include, but are not limited to, formyl (—CHO), acetyl (—C(═O)CH.sub.3), cyclohexylcarbonyl, cyclohexylmethylcarbonyl, benzoyl (—C(═O)Ph), benzylcarbonyl (—C(═O)CH.sub.2Ph), —C(O)—C.sub.1-8 alkyl, —C(O)—(CH.sub.2).sub.t(C.sub.6-10 and), —C(O)—(CH.sub.2).sub.t(5-to 10-membered heteroaryl), —C(O)—(CH.sub.2).sub.t(C.sub.3-10 carbocyclyl), and —C(O)—(CH.sub.2).sub.t(4- to 10-membered heterocyclyl), wherein t is an integer from 0 to 4. In certain embodiments, R is C.sub.1-8 alkyl, substituted with halo or hydroxy; or C.sub.3-10 carbocyclyl, 4- to 10-membered heterocyclyl, C.sub.6-10 aryl, arylalkyl, 5- to 10-membered heteroaryl or heteroaryl alkyl, each of which is substituted with unsubstituted C.sub.1-4 alkyl, halo, unsubstituted C.sub.1-4 alkoxy, unsubstituted C.sub.1-4 haloalkyl, unsubstituted C.sub.1-4 hydroxyalkyl, or unsubstituted C.sub.1-4 haloalkoxy or hydroxy.
[0176] “Acylamino” refers to a radical —NR.sup.22C(O)R.sup.23, where each instance of R.sup.22 and R.sup.23 is independently hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted carbocyclyl, substituted or unsubstituted heterocyclyl, substituted or unsubstituted aryl, or substituted or unsubstituted heteroaryl, as defined herein, or R.sup.22 is an amino protecting group. Exemplary “acylamino” groups include, but are not limited to, formylamino, acetylamino, cyclohexylcarbonylamino, cyclohexylmethyl-carbonylamino, benzoylamino and benzylcarbonylamino. Particular exemplary “acylamino” groups are —NR.sup.24C(O)—C.sub.1-8 alkyl, —NR.sup.24C(O)—(CH.sub.2).sub.t(C.sub.6-10 aryl), —NR.sup.24C(O)—(CH.sub.2).sub.t(5- to 10-membered heteroaryl), —NR.sup.24C(O)—(CH.sub.2).sub.t(C.sub.3-10 carbocyclyl), and —NR.sup.24C(O)—(CH.sub.2).sub.t(4- to 10-membered heterocyclyl), wherein t is an integer from 0 to 4, and each R.sup.24 independently represents H or C.sub.1-8 alkyl. In certain embodiments, R.sup.25 is H, C.sub.1-8 alkyl, substituted with halo or hydroxy; C.sub.3-10 carbocyclyl, 4- to 10-membered heterocyclyl, C.sub.6-10 aryl, arylalkyl, 5-10 membered heteroaryl or heteroaryalkyl, each of which is substituted with unsubstituted C.sub.1-4 alkyl, halo, unsubstituted C.sub.1-4 alkoxy, unsubstituted C.sub.1-4 haloalkyl, un substituted C.sub.1-4 hydroxy alkyl, or unsubstituted C.sub.1-4 haloalkoxy or hydroxy; and R.sup.26 is H, C.sub.1-8 alkyl, substituted with halo or hydroxy; C.sub.3-10 carbocyclyl, 4-10 membered heterocyclyl, C.sub.6-10 aryl, arylalkyl, 5-10 membered heteroaryl or heteroaryalkyl, each of which is substituted with unsubstituted C.sub.1-4 alkyl, halo, unsubstituted C.sub.1-4 alkoxy, unsubstituted C.sub.1-4 haloalkyl, unsubstituted C.sub.1-4 hydroxyalkyl, or unsubstituted C.sub.1-4 haloalkoxy or hydroxyl; provided at least one of R.sup.25 and R.sup.26 is other than H.
[0177] “Acyloxy” refers to a radical —OC(O)R.sup.27, where R.sup.27 is hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted carbocyclyl, substituted or unsubstituted heterocyclyl, substituted or unsubstituted aryl, or substituted or unsubstituted heteroaryl, as defined herein. Representative examples include, but are not limited to, formyl, acetyl, cyclohexylcarbonyl, cyclohexylmethylcarbonyl, benzoyl and benzylcarbonyl. In certain embodiments, R.sup.28 is C.sub.1-8 alkyl, substituted with halo or hydroxy; C.sub.3-10 carbocyclyl, 4- to 10-membered heterocyclyl, C.sub.6-10 aryl, arylalkyl, 5- to 10-membered heteroaryl or heteroaryalkyl, each of which is substituted with unsubstituted C.sub.1-4 alkyl, halo, unsubstituted C.sub.1-4 alkoxy, unsubstituted C.sub.1-4 haloalkyl, unsubstituted C.sub.1-4 hydroxyalkyl, or unsubstituted C.sub.1-4 haloalkoxy or hydroxy.
[0178] “Alkoxy” refers to the group —OR.sup.29 where R.sup.25 is substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted carbocyclyl, substituted or unsubstituted heterocyclyl, substituted or unsubstituted aryl, or substituted or unsubstituted heteroaryl. Particular alkoxy groups are methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, tert-butoxy, sec-butoxy, n-pentoxy, n-hexoxy, and 1,2-dimethylbutoxy. Particular alkoxy groups are lower alkoxy, i.e. with between 1 and 6 carbon atoms. Further particular alkoxy groups have between 1 and 4 carbon atoms.
[0179] In certain embodiments, R.sup.29 is a group that has 1 or more substituents, for instance from 1 to 5 substituents, and particularly from 1 to 3 substituents, in particular 1 substituent, selected from the group consisting of amino, substituted amino, C.sub.6-10 aryl, aryloxy, carboxyl, cyano, C.sub.3-10 carbocyclyl, 3- to 10-membered heterocyclyl, halogen, 5- to 10-membered heteroaryl, hydroxyl, nitro, thioalkoxy, thioaryloxy, thiol, alkyl-S(O)—, aryl-S(O)—, alkyl-S(O).sub.2— and aryl-S(O).sub.2—. Exemplary ‘substituted alkoxy’ groups include, hut are not limited to, —O—(CH.sub.2).sub.t(C.sub.6-10 aryl), —O—(CH.sub.2).sub.t(5- to 10-membered heteroaryl), —O—(CH.sub.2).sub.t(C.sub.3-10 carbocyclyl), and —O—(CH.sub.2).sub.t(4- to 10-membered heterocyclyl), wherein t is an integer from 0 to 4 and any aryl, heteroaryl, carbocyclyl or heterocyclyl groups present, may themselves be substituted by unsubstituted C.sub.1-4 alkyl, halo, unsubstituted C.sub.1-4 alkoxy, unsubstituted C.sub.1-4 haloalkyl, unsubstituted C.sub.1-4 hydroxyalkyl, or unsubstituted C.sub.1-4 haloalkoxy or hydroxy. Particular exemplary ‘substituted alkoxy’ groups are —OCF.sub.3, —OCH.sub.2CF.sub.3, —OCH.sub.2Ph, —OCH.sub.2— cyclopropyl, —OCH.sub.2CH.sub.2OH, and —OCH.sub.2CH.sub.2NMe.sub.2.
[0180] These and other exemplary substituents are described in more detail in the Detailed Description, Examples, and claims. The invention is not intended to be limited in any manner by the above exemplary listing of substituents.
EXAMPLES
[0181] In order that the invention described herein may be more fully understood, the following examples are set forth. The examples described in this application are offered to illustrate the compounds, pharmaceutical compositions, and methods provided herein and are not to be construed in any way as limiting their scope.
Example 1: Comparison of Heterogeneous C.SUB.2.H.SUB.6 .and C.SUB.3.H.SUB.8 .Oxidations to Respective Homogeneous Reactions
[0182]
[0183] At 1% C.sub.2H.sub.6 conversion, the homogeneous reactions show much higher selectivity to C.sub.2H.sub.4 than their heterogeneous counterpart (85% versus 50%, respectively;
[0184] The C.sub.3H.sub.6 oxidation reactions (
Example 2: C.SUB.2.H.SUB.6 .Conversion and C.SUB.2.H.SUB.4 .Selectivity and Yield in Homogeneous Reactions
[0185] When the flow rate (space velocity) of the C.sub.2H.sub.6—O.sub.2—NO mixture with given feed concentration is decreased, the residence time on the gases increases and leads to higher C.sub.2H.sub.6 conversion.
[0186]
[0187] Along with the major product C.sub.2H.sub.4, small amounts of HCHO, CH.sub.3CHO, CO and CO.sub.2 are detected in the product stream as shown in
[0188] These results show that >40% yields of C.sub.2H.sub.4 were obtained on our experiments and further improvements can be made by varying NO pressure, temperature and flow rates. The next example shows similar the conversion-selectivity-yield relations for NO promoted homogeneous gas-phase C.sub.3H.sub.8 oxidation reactions. Subsequently, other factors affecting the attainable yields and the design of optimum homogeneous processes are discussed.
Example 3: C.SUB.3.H.SUB.8 .Conversion and Alkene (C.SUB.3.H.SUB.6., C.SUB.2.H.SUB.4.) Selectivity and Yield in Homogeneous Reactions
[0189]
[0190]
[0191] Thus, simple moderate temperature processes with yields relevant to practical alkane dehydrogenation process are achievable in NO promoted homogeneous gas-phase oxidation processes, which can be improved further by optimizing reaction conditions. Next, we change different process conditions to assess their impacts on the performances. In particular, it is shown that (i) temperature increases and H.sub.2O co-feeds can improve conversion and selectivity and (ii) Increasing alkane and O.sub.2 pressure retains the high conversion and selectivity and improves it to some extent suggesting the applicability of this process even in denser reactant feeds for more practical processes. In many cases, where only the results of C.sub.2H.sub.6 reactions are shown, C.sub.3H.sub.8 reactions were also performed and showed analogous effects.
Example 4: Effect of Reactor Volume on Alkane Conversion and Alkene Selectivity
[0192] Two different quartz reactors of similar shapes with different bulb sizes leading to reactor volumes of 5.9 and 12 cm.sup.3 were used (
Example 5: Effect of Reactor Temperature
[0193] C.sub.2H.sub.6 ODH reactions were performed by flowing 3 kPa C.sub.2H.sub.6, 10 kPa O.sub.2 and 0 or 0.01 kPa NO, with He as diluent and a 30 cc/min total inlet flow rate at moderate temperatures (723-823 K).
Example 6: Effect of C.SUB.2.H.SUB.6 .Pressure on C.SUB.2.H.SUB.6 .Conversion and Product Selectivity
[0194] C.sub.2H.sub.6 ODH reactions were performed by flowing 10 kPa O.sub.2, 0 or 0.01 kPa NO and varying the C.sub.2H.sub.6 pressure from 1.5 to 11 kPa with He as diluent and a total inlet flow rate of 30 cc/min at 823 K.
Example 7: Effect of O.SUB.2 .Pressure on C.SUB.2.H.SUB.6 .Conversion and Product Selectivity
[0195] C.sub.2H.sub.6 ODH reactions were performed by flowing 3 kPa C.sub.2H.sub.6, 0 or 0.01 kPa NO and 1-18 kPa O.sub.2 pressure with He as diluent and a total inlet flow rate of 30 cc/min at 823 K.
Example 8: Effect of Water Vapor Pressure on C.SUB.2.H.SUB.6 .Conversion and Product Selectivity
[0196] C.sub.2H.sub.6 ODH reactions were performed by flowing 3 kPa C.sub.2H.sub.6, 10 kPa O.sub.2, 0.01 kPa NO and 0 to 10 kPa pressure of H.sub.2O vapor with He as diluent and a total inlet flow rate of 30 cc/min at 873 K.
Example 9: Effect of Cofeeding NO in the Presence of Catalytic or Inert Solids
[0197]
[0198] The effect of inert solids was assessed by filling quartz reactor with nitric acid washed SiO.sub.2 powder that was found to be inert, relative to VO.sub.x/SiO.sub.2 and MoO.sub.x/SiO.sub.2 catalysts for C.sub.2H.sub.6 ODH reaction.
[0199]
Example 10: Oxygenates Selectivity and Production of Propylene Oxide
[0200] The selectivity in the formation of oxygenates in the activation of C.sub.3H.sub.8 in an empty 12 cm.sup.3 reactor with 0.005 kPa NO, and on V.sub.2O.sub.5 catalyst without NO feed, at 773 K, 3 kPa C.sub.3H.sub.8, and 10 kPa O.sub.2 are shown in
Example 11: Conversion of C.SUB.2.H.SUB.4 .and CH.SUB.3.OH to C.SUB.3.H.SUB.6 .in a Gas-Phase OCP Reaction
[0201] Homogeneous gas-phase OCP reactions of C.sub.2H.sub.4 (40 kPa) and CH.sub.3OH (5 kPa) were performed in the presence of 5 kPa O.sub.2 and 300 ppm NO at 60 cm.sup.3 min.sup.−1 total flow rate in a 12 cm.sup.3 empty U-tube quartz reactor at two different temperatures (723 K and 773 K). Feed gases (i.e., C.sub.2H.sub.4, O.sub.2, NO, and diluent helium) were flown using an electronic mass flow controller. Liquid methanol was evaporated in the flowing stream of feed gases to carry out the gas-phase OCP reactions. Products including C.sub.3H.sub.6 and C.sub.3H.sub.8, as shown in Table 1 below, were obtained. It revealed that NO mediated radical reactions can also be used for C—C bond formation to prepare valuable longer-chain alkenes.
TABLE-US-00001 TABLE 1 Measured reactant conversion and coupling product selectivity in NO mediated homogeneous coupling of C.sub.2H.sub.4 and CH.sub.3OH. CH.sub.3OH C.sub.2H.sub.4 C.sub.3H.sub.6 C.sub.3H.sub.8 Temperature conversion conversion selectivity selectivity (K) (%) (%) (%) (%) 723 0.67 0.15 6.5 10.5 773 4.5 1.0 7.7 1.8
Example 12. C.SUB.3.H.SUB.8 .Activation Rates and Selectivities in C.SUB.3.H.SUB.8.—O.SUB.2.—NO Reactions
[0202]
[0203] Large enhancements in rates of alkane activation by NO.sub.x have studied previously for the direct conversion of CH.sub.4 to oxygenate such as HCHO. The NO.sub.x catalyzed reactions led to greater HCHO selectivity than heterogeneous routes, but the yields remained well below 10% and significant side reactions that introduced nitrogen into hydrocarbons were observed due to large NO.sub.x feed concentrations up to 5 kPa. We show here that much smaller NO concentrations can be used to selectively convert C.sub.3H.sub.8 to alkenes (
[0204] The mechanism of NO.sub.x catalyzed conversions hydrocarbons such as CH.sub.4 involve the generation of OH radicals. These radicals have been detected by laser induced fluorescence measurements for CH.sub.4/O.sub.2/NO.sub.x reactions and their role as predominant abstractors of H atoms from strong C—H bonds has been determined from kinetic simulations. The OH radicals generated from H.sub.2O and O.sub.2 in alkali promoted oxides and molten salt catalysts at high temperatures have also been shown to activate hydrocarbons. Therefore, we probe the role of H.sub.2O in further enhancing NO.sub.x mediated C.sub.3H.sub.8 conversions by co-feeding H.sub.2O to C.sub.3H.sub.8—O.sub.2 reactants with and without NO.sub.x catalysts, as shown in
Example 13. Differences in Rates and Selectivity Between NO.SUB.x .Mediated Pathways and V.SUB.2.O.SUB.5 .Catalysts
[0205] C.sub.3H.sub.8 activation on vanadium-based oxide catalysts occurs via Mars van Krevelen redox cycles, where lattice oxygen species shown in Table 2 (V=O* species) act as predominant H-abstractors. C—H activations at these sites lead to reduced centers existing as OH pairs or as O-vacancies formed by dihydroxylations at OH pairs. These reduced centers are re-oxidized by rapid O.sub.2 activations to restore the V=O* sites. The rapid nature of the re-oxidation steps leads to most of the catalyst existing as V=O* and nearly fixed number of these abstractors at different reaction conditions. In contrast, the NO.sub.x mediated cycles lead to OH radicals as predominant abstractors of strong C—H bonds in C.sub.3H.sub.8. The concentration of these abstractors varies with reaction conditions due to changes in concentrations of sacrificial H atom donors to NO.sub.2 and presence of H.sub.2O. These differences influence how change in C.sub.3H.sub.8 conversion via changing residence time affects reaction rates in the two types of reactions.
[0206] The homogeneous and heterogeneous systems also exhibit large differences in selectivity trends (
and the selectivity (S.sub.C.sub.
Regression of S.sub.C.sub.
Example 14. Effects of Reactant Pressures on Rates and Selectivity
[0207] The effect of O.sub.2 pressure on C.sub.3H.sub.8 activation rates in the 12 cm.sup.3 quartz reactor at different temperatures is shown in
[0208] The effect of C.sub.3H.sub.8 pressure on C.sub.3H.sub.8 activation rates in 12 cm.sup.3 quartz reactor at different temperatures is shown in
[0209] The effect of H.sub.2O pressure from H.sub.2O co-fed with reactants and formed from C.sub.3H.sub.8—O.sub.2 conversions on rates and selectivity are shown in
[0210] These effects of reactant pressures deviate significantly from ODH reactions on oxide catalysts that involve Mars van Krevelen (MvK) cycles with rate limiting C—H activation at lattice O-atoms of oxides and fast O.sub.2 activation. Such mechanisms invariably exhibit a first-order dependence on alkane pressure and zero-order dependence on O.sub.2 pressure. The ODH rates in MvK cycles show small decrease in rates with H.sub.2O pressures due to its adsorption at active sites. The results in NO.sub.x mediated reactions (
[0211] The C.sub.3H.sub.6 selectivity data as a function of conversion for the different reactant pressures and reaction temperatures shown in
[0212]
Example 15. Effect of Abstractor Strength on Activation Enthalpy Differences for Steps Involving C—H Bonds of Different Strengths
[0213]
[0214] The effects of temperature on rate constant ratios, at identical reactant pressures in
where, ΔH.sub.1.sup.act and ΔH.sub.2.sup.act represent ensemble averaged activation enthalpy for C.sub.3H.sub.6 formation and all steps mediating parallel C.sub.3H.sub.8 oxidation steps relative to gaseous C.sub.3H.sub.8 (
TABLE-US-00002 TABLE 2 Activation enthalpy differences between the parallel or sequential reactions and the primary C—H activations derived from regression of rate constants ratios in FIG. 9 to the form of Equation 3 and 4. Uncertainties represent the standard errors. Reaction ΔH.sub.2.sup.act-ΔH.sub.1.sup.act ΔH.sub.3.sup.act-ΔH.sub.1.sup.act System (kJ mol.sup.−1) (kJ mol.sup.−1) V.sub.2O.sub.5 −33 ± 34 −26 ± 1 NO.sub.x mediated 15 ± 10 −3 ± 3
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INCORPORATION BY REFERENCE
[0249] All U.S. and PCT patent application publications and U.S. patents mentioned herein are hereby incorporated by reference in their entirety as if each individual publication or patent was specifically and individually indicated to be incorporated by reference. In case of conflict, the application, including any definitions herein, will control.
Other Embodiments
[0250] In the claims articles such as “a,” “an,” and “the” may mean one or more than one unless indicated to the contrary or otherwise evident from the context. Claims or descriptions that include “or” between one or more members of a group are considered satisfied if one, more than one, or all of the group members are present in, employed in, or otherwise relevant to a given product or process unless indicated to the contrary or otherwise evident from the context. The invention includes embodiments in which exactly one member of the group is present in, employed in, or otherwise relevant to a given product or process. The invention includes embodiments in which more than one, or all of the group members are present in, employed in, or otherwise relevant to a given product or process.
[0251] Furthermore, the invention encompasses all variations, combinations, and permutations in which one or more limitations, elements, clauses, and descriptive terms from one or more of the listed claims is introduced into another claim. For example, any claim that is dependent on another claim can be modified to include one or more limitations found in any other claim that is dependent on the same base claim. Where elements are presented as lists, e.g., in Markush group format, each subgroup of the elements is also disclosed, and any element(s) can be removed from the group. It should it be understood that, in general, where the invention, or aspects of the invention, is/are referred to as comprising particular elements and/or features, certain embodiments of the invention or aspects of the invention consist, or consist essentially of, such elements and/or features. For purposes of simplicity, those embodiments have not been specifically set forth in haec verba herein. It is also noted that the terms “comprising” and “containing” are intended to be open and permits the inclusion of additional elements or steps. Where ranges are given, endpoints are included. Furthermore, unless otherwise indicated or otherwise evident from the context and understanding of one of ordinary skill in the art, values that are expressed as ranges can assume any specific value or sub-range within the stated ranges in different embodiments of the invention, to the tenth of the unit of the lower limit of the range, unless the context clearly dictates otherwise.
[0252] This application refers to various issued patents, published patent applications, journal articles, and other publications, all of which are incorporated herein by reference. If there is a conflict between any of the incorporated references and the instant specification, the specification shall control. In addition, any particular embodiment of the invention that falls within the prior art may be explicitly excluded from any one or more of the claims. Because such embodiments are deemed to be known to one of ordinary skill in the art, they may be excluded even if the exclusion is not set forth explicitly herein. Any particular embodiment of the invention can be excluded from any claim, for any reason, whether or not related to the existence of prior art.
[0253] Those skilled in the art will recognize or be able to ascertain using no more than routine experimentation many equivalents to the specific embodiments described herein. The scope of the embodiments described herein is not intended to be limited to the above Description, but rather is as set forth in the appended claims. Those of ordinary skill in the art will appreciate that various changes and modifications to this description may be made without departing from the spirit or scope of the invention, as defined in the following claims.