Method for isolation of an aromatic dianhydride and aromatic dianhydrides prepared by the method

Abstract

A method for producing an aromatic dianhydride includes reacting an aromatic diimide with a substituted or unsubstituted phthalic anhydride in an aqueous medium in the presence of an amine exchange catalyst to provide an aqueous reaction mixture including an N-substituted phthalimide, an aromatic tetraacid salt, and at least one of an aromatic triacid salt and an aromatic imide diacid salt. The method further includes removing the phthalimide from the aqueous reaction mixture by extracting the aqueous reaction mixture with an organic solvent using a single packed extraction column. The aromatic tetraacid salt is converted to the corresponding aromatic dianhydride. Aromatic dianhydrides prepared according to the method are also described.

Claims

1. A method for producing an aromatic dianhydride, the method comprising reacting an aromatic diimide with a substituted or unsubstituted phthalic anhydride in an aqueous medium in the presence of an amine exchange catalyst under conditions effective to provide an aqueous reaction mixture comprising an N-substituted phthalimide, an aromatic tetraacid salt, and at least one of an aromatic triacid salt and an aromatic imide diacid salt, wherein the reacting is at a reaction temperature that is 140 to 250 C. and a reaction pressure of 1.13 to 2.16 MPa; removing the phthalimide from the aqueous reaction mixture by extracting the aqueous reaction mixture with an organic solvent in a single packed extraction column comprising a structured metal v-shaped packing; and converting the aromatic tetraacid salt to the corresponding aromatic dianhydride; wherein the aromatic diimide is of the formula ##STR00018## the substituted or unsubstituted phthalic anhydride is of the formula ##STR00019## the N-substituted phthalimide is of the formula ##STR00020## the aromatic tetraacid salt is of the formula ##STR00021## the aromatic triacid salt is of the formula ##STR00022## and the aromatic imide diacid salt is of the formula ##STR00023## and the aromatic dianhydride is of the formula ##STR00024## wherein in the forgoing formulas T is O, S, C(O), SO.sub.2, SO, C.sub.yH.sub.2y wherein y is an integer from 1 to 5 or a halogenated derivative thereof or OZO, wherein Z is an aromatic C.sub.6-24 monocyclic or polycyclic moiety optionally substituted with 1 to 6 C.sub.1-8 alkyl groups, 1 to 8 halogen atoms, or a combination comprising at least one of the foregoing; R.sup.1 is a monovalent C.sub.1-13 organic group; X is fluoro, chloro, bromo, iodo, or nitro; n is 0 or 1; and Y is a cationic group or a proton.

2. The method of claim 1, wherein conversion to the aromatic dianhydride is at least 75%.

3. The method of claim 1, wherein the method comprises at least one of the following process parameters: (a) a volumetric ratio of the organic solvent to the aqueous reaction mixture of 0.5:1 to 1.5:1; (b) an extraction column operating capacity of 8.149 to 24.47 (m.sup.3/hr)/m.sup.2; (c) a dispersed phase hold up of at least 3%; and (d) a continuous phase residence time of less than one hour.

4. The method of claim 3, wherein the method comprises process parameter (a).

5. The method of claim 3, wherein the method comprises process parameter (b).

6. The method of claim 3, wherein the method comprises process parameter (c).

7. The method of claim 3, wherein the method comprises process parameter (d).

8. The method of claim 3, wherein the method comprises at least two of the process parameters, or at least three of the process parameters, or at least four of the process parameters.

9. The method of claim 3, wherein the method comprises each of process parameters (a), (b), (c), and (d).

10. The method of claim 3, wherein the method comprises process parameters (a) and (b).

11. The method of claim 1, wherein the substituted or unsubstituted phthalic anhydride comprises phthalic anhydride, 3-halophthalic anhydride, 4-halophthalic anhydride, 3-nitrophthalic anhydride, 4-nitrophthalic anhydride, or a combination comprising at least one of the foregoing; and the exchange catalyst comprises a (C.sub.1-20 alkyl)-substituted amine.

12. The method of claim 1, wherein the initial molar ratio of the substituted or unsubstituted phthalic anhydride to aromatic diimide is 4:1 to 20:1.

13. The method of claim 1, wherein the initial molar ratio of amine exchange catalyst to the substituted or unsubstituted phthalic anhydride is 1:1 to 2:1.

14. The method of claim 1, wherein the aromatic diimide comprises 4,4-bisphenol A-bis-N-methylphthalimide, 3,4-bisphenol A-bis-N-methylphthalimide, 3,3-bisphenol A-bis-N-methylphthalimide, or a combination comprising at least one of the foregoing; the aromatic dianhydride comprises 4,4-bisphenol A-bis-dianhydride, 3,4-bisphenol A-bis-dianhydride, 3,3-bisphenol A-bis-dianhydride, or a combination comprising at least one of the foregoing; and the organic solvent comprises toluene, xylene, chlorobenzene, ortho-dichlorobenzene, or a combination comprising at least one of the foregoing.

15. The method of claim 1, wherein the removing is at an extraction temperature of 100 to 250 C.

16. The method of claim 1, wherein the method is a continuous method.

17. The method of claim 1, wherein the aromatic dianhydride comprises 0.1 to 3 wt % imide anhydride, based on the total weight of the aromatic dianhydride.

Description

EXAMPLES

(1) In the present Examples, the bisimide/dianhydride exchange reaction was carried out using the following general procedure.

(2) In a typical procedure, a reactor was charged with 4,4-bisphenol A-bis-N-methylphthalimide (which can also include small amounts of 3,4-bisphenol A-bis-N-methylphthalimide and 3,3-bisphenol A-bis-N-methylphthalimide) and phthalic anhydride in a molar ratio of phthalic anhydride to bisimide of 4.2:1. The reaction was conducted in the presence of a triethylamine (TEA) exchange catalyst. The TEA was used in a TEA:phthalic anhydride molar ratio of 1.25:1. Water was used as the solvent to provide an aqueous reaction mixture having a solids content (% solids) in the range of 14 to 15%. The bisimide/dianhydride exchange reaction was carried out at a temperature of 160 to 165 C. for 1 hour and at a pressure of 160 psig. For simplicity of the discussion that follows, N-methylphthalimide will be referred to as PI, the 4,4-bisphenol A-bis-N-methylphthalimide mixture will be referred to as BI, and the 4,4-bisphenol A dianhydride product will be referred to as DA.

(3) The following examples were conducted using a 4 inch diameter extraction column. The aqueous reaction mixture outlet from the reactor was preheated and continuously fed into the top of the extraction column. The aqueous reaction mixture entering the extraction column had the following composition: 6.06 wt % PI; 11.284 wt % phthalic anhydride; 7.67 wt % DA; 5.32 wt % imide anhydride (IA); 1.41 wt % residual BI; 53.4 wt % water; and 14.86 wt % TEA exchange catalyst. This composition corresponds to the following molar fractions: 0.541 DA; 0.365 IA; and 0.094 BI, based on BI molar equivalents.

(4) Toluene containing 5 weight percent (wt %) TEA was used as the organic solvent and was also preheated and continuously fed into the bottom of the extraction column. The process parameters that were examined include extractor capacity, organic solvent:aqueous medium ratio, toluene flow rate, and dispersed phase holdup. Dispersed phase holdup was measured using the shutoff valve method. The column packing material was structured sheet metal V-shaped packing (SMVP) material.

(5) Table 1 shows a summary of experiments that were conducted at lower capacity (e.g., capacity of 220-230 gallons per hour per square foot (Gph/sq ft)). The results shown in Table 1 indicate that the imide anhydride lost to back reaction can be 16-34% depending on the operational parameters employed. For example, higher toluene flow rates (e.g., greater than 35 kg/hr) resulted in only 16% imide anhydride lost to back reaction.

(6) Experiments were also conducted to study the effect of toluene flow rate at higher capacity (440-550 Gph/sq ft). These results are also shown in Table 1. These results show that imide anhydride lost to back reaction can be varied from 16-23% based on the toluene flow rate employed. For example, a toluene flow rate of greater than about 65 kg/hr at high capacity can lead to significant improvement in the amount of imide anhydride lost to back reaction (i.e., reduction to about 14-16%).

(7) In Table 1, Capacity refers to the total flow into the column (e.g., flow of the combined aqueous and organic streams) per unit area. Aqueous flow rate refers to the rate at which the aqueous phase enters the column from the reactor. Organic flow rate refers to the rate at which the organic phase enters the column. IA lost to organic refers to the amount of imide-anhydride species that is solubilized in the organic phase, and thus extracted from the column with phthalamide (PI) and bisimide (BI). IA lost to back reaction refers to the amount of the imide-anhydride species that are converted back to BI starting material, and then extracted into the organic phase and removed from the column. IA to DA refers to the conversion of the imide-anhydride species to the desired dianhydride tetra-acid salt. IA remaining in aq refers to the amount of imide-anhydride species in the aqueous phase during the extraction (where imide anhydride species is defined above, and can include imide anhydride, as well as the corresponding diacid imide, triacid amide, and salts thereof). BI extraction efficiency and PI extraction efficiency refer to the amount of BI and PI, respectively that are removed from the column during the extraction based on the weight of each in the feed. It is noted that some small amount of BI or PI or both can remain in the aqueous phase.

(8) Extraction was carried out at a temperature of 170 to 180 C. and at a pressure of 200 to 250 psig.

(9) TABLE-US-00001 TABLE 1 Residence IA lost Aq. Org. Org./Aq. time of Column to organic Capacity Flowrate Flow rate Vol. Aq. Phase Temp phase Ex. (Gph/sq ft) (kg/hr) (kg/hr) Ratio (min) ( C.) (mol %) 1 230 39.2 35.1 1 114 171-174 1 2 220 35.4 37.5 1.4 105 171-174 2 3 230 44.4 34.3 0.8 115 171-174 0.3 4 460 79.4 64.3 1 55 170-180 1 5 460 73.9 60.6 1 56 171-174 1 6 550 84.4 78.8 1 44 171-174 0.2 7 440 67.2 77.5 1.4 46 171-174 1 8 460 84.9 61.5 0.8 60 171-174 0.3 IA lost IA BI PI IA to back IA to Overall DA remaining extraction extraction relative reaction DA Molar Yield in aq efficiency efficiency to DA Ex. (mol %) (mol %) (mol %) (mol %) (wt %) (wt %) (wt. %) 1 23 74 81.1 3 96 98 1.23 2 16 80 83.3 2 95 98.8 0.95 3 34 63 77.1 3 97 98 1.22 4 23 74 81.1 3 96 98 1.4 5 21 75 81.5 3 96 98 1.22 6 14 82 84.0 3 94 98 1.42 7 16 80 83.3 3 93 98.8 1.22 8 21 74 81.1 4 96 99 2

(10) As described above, the inlet feed composition (i.e., the composition of the aqueous feed leaving the reactor and entering the extraction column) corresponded to the following molar fractions: 0.541 DA; 0.365 IA; and 0.094 BI. After conducting the extraction, the overall yield of the desired DA was greater than 60% as shown in Table 1. For example, looking at example 7 above, the overall DA yield can be calculated as 0.541 moles of DA+(0.365 moles of IA*0.8 moles of IA converted to DA). Thus, the product stream of example 7 achieves 83.3% overall DA molar yield (0.541+(0.365*0.80)=0.833*100=83.5% DA at the end of the extraction).

(11) Additional experiments were conducted to study the effect of toluene flow rate on the imide anhydride species back reaction at constant aqueous flow rate. The results, which are summarized in Table 2, show that the amount of imide anhydride species lost to back reaction varies from 14-22%, resulting in an overall DA yield of 82.6 to 85.5%, depending on the toluene flow rate, the dispersed phase holdup, and the continuous phase residence time. Each of the parameters in Table 2 are as defined above for Table 1. Dispersed phase holdup refers to the volumetric holdup in the column (i.e., the amount of the total volume of the liquid in the column that is the dispersed phase).

(12) TABLE-US-00002 TABLE 2 IA lost IA Dispersed Continuous Aq. Org. IA lost to back IA to Overall remaining phase phase Capacity flow rate flow rate to Org. reaction DA DA Yield in aq. hold up residence time Ex. (gph/sq. ft) (kg/hr) (kg/hr) (mol %) (mol %) (mol %) (mole %) (mol %) (vol %) (min) 9 460 73.9 60.6 1 21 75 82.9 3 5.2 56 10 530 75.7 85.8 0.5 14 83 85.5 3 7.1 41 11 420 75.5 49.8 0.4 22 75 82.6 3 3.4 76

(13) The results provided by the present examples show that a dispersed phase holdup of 6-8% and a continuous phase residence time of 40 minutes will result in about 14% of imide anhydride lost to the back reaction.

(14) Advantageously, the DA produced by the method of the present disclosure was reliably consistent in composition, in particular with respect to imide anhydride content. The aqueous stream obtained from the extraction column (i.e., after conducting the extraction) was subjected to thermal treatment under vacuum which consistently produced the desired aromatic dianhydride having an imide anhydride content of 10.2 wt %.

(15) As a Comparative Example, the process of the present disclosure using a SMVP packed column was compared to a method using an extraction with a single GOODLOE packed extraction column. Reaction was carried out at a PA:BI molar ratio of 4.5:1 to 5:1 at a triethylamine TEA:PA molar ratio of 2:1. Solids content (% solids) was maintained in the range of 13 to 15%. The reaction was conducted at 170 C. at a pressure of 230 psig with a residence time of 1 hour. The aqueous feed was fed to the top of GOODLOE packed extraction column, and toluene containing 5 weight percent (wt %) TEA was continuously fed to the bottom of extraction column. The aqueous feed composition entering the extraction column was 45 mol % dianhydride as triethylammonium salts, 40 mol % IA as triethylammonium salts, and 15 mol % BI, all based on BI mole equivalents used in the reaction. Extraction was carried out with a temperature range of 145 to 170 C. with the pressure range of 200 to 250 psig.

(16) Results from three comparative examples are shown in Table 3 below. Table 3 shows the amount of IA lost to back reaction (33 to 45 mole percent) and the resulting molar conversion of BI to DA (67 to 72%). As discussed above, the use of the single SMVP packed column resulted in 14 mole percent back reaction with a molar conversion of 84 to 85% BI to DA. Without wishing to be bound by theory, it is believed that the differences between the inventive examples and comparative examples can, at least in part, be attributed to the extraction in the comparative examples being less efficient, causing more BI to be formed, which cannot be converted to DA. Thus, the increased conversion of IA to DA in the SMVP packed column is believed to be due to the increased extraction efficiency.

(17) TABLE-US-00003 TABLE 3 Organic:Aqueous Maximum Minimum IA lost to BI to DA Comparative ratio capacity capacity back rxn Conversion IA relative DA Example (Vol) (gph/Sq. ft) (gph/sq. ft) (mol %) (mol %) (wt %) C1 1.4 361.26 177.24 33 72 2.5 C2 1.2 358.02 155.1 38 70 2.5 to 3 C3 1 325.44 141 45 67 2.5 to 3

(18) Thus, the use of a SMVP packed extraction column can offer several advantages, including >80% DA yield achieved using single column configuration operated in a conventional manner. The SMVP packed column can also have a better flowrate turndown ratio and aqueous/organic interface control, which helps in flexibility of running the plants at minimal and higher throughputs.

(19) This disclosure further encompasses the following aspects.

(20) Aspect 1: A method for producing an aromatic dianhydride, the method comprising reacting an aromatic diimide with a substituted or unsubstituted phthalic anhydride in an aqueous medium in the presence of an amine exchange catalyst under conditions effective to provide an aqueous reaction mixture comprising an N-substituted phthalimide, an aromatic tetraacid salt, and at least one of an aromatic triacid salt and an aromatic imide diacid salt, wherein the reacting is at a reaction temperature that is 140 to 250 C. and a reaction pressure of 1.13 to 2.16 MPa (150 to 300 psig), preferably 1.48 to 1.82 MPa (200 to 250 psig); removing the phthalimide from the aqueous reaction mixture by extracting the aqueous reaction mixture with an organic solvent in a single packed extraction column comprising a structured metal v-shaped packing; and converting the aromatic tetraacid salt to the corresponding aromatic dianhydride; wherein the aromatic diimide is of the formula

(21) ##STR00011##
the substituted or unsubstituted phthalic anhydride is of the formula

(22) ##STR00012##
the N-substituted phthalimide is of the formula

(23) ##STR00013##
the aromatic tetraacid salt is of the formula

(24) ##STR00014##
the aromatic triacid salt is of the formula

(25) ##STR00015##
and the aromatic imide diacid salt is of the formula

(26) ##STR00016##
and the aromatic dianhydride is of the formula

(27) ##STR00017##
wherein in the forgoing formulas T is O, S, C(O), SO.sub.2, SO, C.sub.yH.sub.2y wherein y is an integer from 1 to 5 or a halogenated derivative thereof or OZO, wherein Z is an aromatic C.sub.6-24 monocyclic or polycyclic moiety optionally substituted with 1 to 6 C.sub.1-8 alkyl groups, 1 to 8 halogen atoms, or a combination comprising at least one of the foregoing; R.sup.1 is a monovalent C.sub.1-13 organic group; X is fluoro, chloro, bromo, iodo, nitro, or a combination comprising at least one of the foregoing; n is 0 or 1; and Y is a cationic group, preferably a C.sub.1-20 trialkylammonium group or a proton.

(28) Aspect 2: The method of aspect 1, wherein conversion to the aromatic dianhydride is at least 75%, preferably at least 80%.

(29) Aspect 3: The method of aspect 1 or 2, wherein the method comprises at least one of the following process parameters: (a) a volumetric ratio of the organic solvent to the aqueous reaction mixture of 0.5:1 to 1.5:1, preferably 0.8:1 to 1:1; (b) an extraction column operating capacity of 8.149 to 24.47 (m3/hr)/m2 (200 to 600 Gph/Sq.Math.ft), preferably 17.520 to 22.817 (m3/hr)/m2 (430 to 560 Gph/sq ft); (c) a dispersed phase hold up of at least 3%, preferably 5%, more preferably 5 to 10%, even more preferably 6 to 8%; and (d) a continuous phase residence time of less than one hour, preferably less than 45 minutes.

(30) Aspect 4: The method of aspect 3, wherein the method comprises process parameter (a).

(31) Aspect 5: The method of aspect 3, wherein the method comprises process parameter (b).

(32) Aspect 6: The method of aspect 3, wherein the method comprises process parameter (c).

(33) Aspect 7: The method of aspect 3, wherein the method comprises process parameter (d).

(34) Aspect 8: The method of aspect 3, wherein the method comprises at least two of the process parameters, or at least three of the process parameters, or at least four of the process parameters.

(35) Aspect 9: The method of aspect 3, wherein the method comprises each of process parameters (a), (b), (c), and (d).

(36) Aspect 10: The method of aspect 3, wherein the method comprises process parameters (a) and (b).

(37) Aspect 11: The method of any of aspects 1 to 10, wherein the substituted or unsubstituted phthalic anhydride comprises phthalic anhydride, 3-halophthalic anhydride, 4-halophthalic anhydride, 3-nitrophthalic anhydride, 4-nitrophthalic anhydride, or a combination comprising at least one of the foregoing, preferably phthalic anhydride; and the exchange catalyst comprises a (C.sub.1-20 alkyl)-substituted amine, preferably a tri(C.sub.1-20 alkyl)amine, more preferably triethylamine.

(38) Aspect 12: The method of any of aspects 1 to 11, wherein the initial molar ratio of phthalic anhydride to aromatic diimide is 4:1 to 20:1, or 4:1 to 10:1, or 4:1 to 8:1, or 4:1 to 5.5:1.

(39) Aspect 13: The method of any of aspects 1 to 12, wherein the initial molar ratio of amine exchange catalyst to the phthalic anhydride is 1:1 to 2:1.

(40) Aspect 14: The method of any of aspects 1 to 13, wherein the aromatic diimide comprises 4,4-bisphenol A-bis-N-methylphthalimide, 3,4-bisphenol A-bis-N-methylphthalimide, 3,3-bisphenol A-bis-N-methylphthalimide, or a combination comprising at least one of the foregoing; the aromatic dianhydride comprises 4,4-bisphenol A-bis-dianhydride, 3,4-bisphenol A-bis-dianhydride, 3,3-bisphenol A-bis-dianhydride, or a combination comprising at least one of the foregoing; and the organic solvent comprises toluene, xylene, chlorobenzene, ortho-dichlorobenzene, or a combination comprising at least one of the foregoing, preferably toluene.

(41) Aspect 15: The method of any of aspects 1 to 14, wherein the removing is at an extraction temperature of 100 to 250 C.

(42) Aspect 16: The method of any of aspects 1 to 15, wherein the method is a continuous method.

(43) Aspect 17: The method of any of aspects 1 to 16, wherein the aromatic dianhydride comprises 0.1 to 3 wt %, or 0.5 to 3 wt %, or 0.5 to 2.5 wt %, or 0.5 to 2 wt %, or 0.6 to 1.6 wt %, or 0.7 to 1.3 wt %, or 0.8 to 1.2 wt % imide anhydride, based on the total weight of the aromatic dianhydride.

(44) Aspect 18: An aromatic dianhydride made by the method of any of aspects 1 to 17, wherein the aromatic dianhydride has an imide anhydride content of 0.1 to 3 wt %, or 0.5 to 3 wt %, or 0.5 to 2.5 wt %, or 0.5 to 2 wt %, or 0.6 to 1.6 wt %, or 0.7 to 1.3 wt %, or 0.8 to 1.2 wt % imide anhydride, based on the total weight of the aromatic dianhydride.

(45) The compositions, methods, and articles can alternatively comprise, consist of, or consist essentially of, any appropriate materials, steps, or components herein disclosed. The compositions, methods, and articles can additionally, or alternatively, be formulated so as to be devoid, or substantially free, of any materials (or species), steps, or components, that are otherwise not necessary to the achievement of the function or objectives of the compositions, methods, and articles.

(46) All ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other. Combinations is inclusive of blends, mixtures, alloys, reaction products, and the like. The terms first, second, and the like, do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The terms a and an and the do not denote a limitation of quantity, and are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Or means and/or unless clearly stated otherwise. Reference throughout the specification to some aspects, an aspect, and so forth, means that a particular element described in connection with the aspect is included in at least one aspect described herein, and may or may not be present in other aspects. In addition, it is to be understood that the described elements may be combined in any suitable manner in the various aspects.

(47) Unless specified to the contrary herein, all test standards are the most recent standard in effect as of the filing date of this application, or, if priority is claimed, the filing date of the earliest priority application in which the test standard appears.

(48) Unless defined otherwise, technical and scientific terms used herein have the same meaning as is commonly understood by one of skill in the art to which this application belongs. All cited patents, patent applications, and other references are incorporated herein by reference in their entirety. However, if a term in the present application contradicts or conflicts with a term in the incorporated reference, the term from the present application takes precedence over the conflicting term from the incorporated reference.

(49) Compounds are described using standard nomenclature. For example, any position not substituted by any indicated group is understood to have its valency filled by a bond as indicated, or a hydrogen atom. A dash (-) that is not between two letters or symbols is used to indicate a point of attachment for a substituent. For example, CHO is attached through carbon of the carbonyl group.

(50) As used herein, the term hydrocarbyl, whether used by itself, or as a prefix, suffix, or fragment of another term, refers to a residue that contains only carbon and hydrogen. The residue can be aliphatic or aromatic, straight-chain, cyclic, bicyclic, branched, saturated, or unsaturated. It can also contain combinations of aliphatic, aromatic, straight chain, cyclic, bicyclic, branched, saturated, and unsaturated hydrocarbon moieties. However, when the hydrocarbyl residue is described as substituted, it may, optionally, contain heteroatoms over and above the carbon and hydrogen members of the substituent residue. Thus, when specifically described as substituted, the hydrocarbyl residue can also contain one or more carbonyl groups, amino groups, hydroxyl groups, or the like, or it can contain heteroatoms within the backbone of the hydrocarbyl residue. The term alkyl means a branched or straight chain, unsaturated aliphatic hydrocarbon group, e.g., methyl, ethyl, n-propyl, i-propyl, n-butyl, s-butyl, t-butyl, n-pentyl, s-pentyl, and n- and s-hexyl. Alkenyl means a straight or branched chain, monovalent hydrocarbon group having at least one carbon-carbon double bond (e.g., ethenyl (HCCH.sub.2)). Alkoxy means an alkyl group that is linked via an oxygen (i.e., alkyl-O), for example methoxy, ethoxy, and sec-butyloxy groups. Alkylene means a straight or branched chain, saturated, divalent aliphatic hydrocarbon group (e.g., methylene (CH.sub.2) or, propylene ((CH.sub.2).sub.3)). Cycloalkylene means a divalent cyclic alkylene group, C.sub.nH.sub.2n-x, wherein x is the number of hydrogens replaced by cyclization(s). Cycloalkenyl means a monovalent group having one or more rings and one or more carbon-carbon double bonds in the ring, wherein all ring members are carbon (e.g., cyclopentyl and cyclohexyl). Aryl means an aromatic hydrocarbon group containing the specified number of carbon atoms, such as phenyl, tropone, indanyl, or naphthyl. Arylene means a divalent aryl group. Alkylarylene means an arylene group substituted with an alkyl group. Arylalkylene means an alkylene group substituted with an aryl group (e.g., benzyl). The prefix halo means a group or compound including one more of a fluoro, chloro, bromo, or iodo substituent. A combination of different halo groups (e.g., bromo and fluoro), or only chloro groups can be present. The prefix hetero means that the compound or group includes at least one ring member that is a heteroatom (e.g., 1, 2, or 3 heteroatom(s)), wherein the heteroatom(s) is each independently N, O, S, Si, or P. Substituted means that the compound or group is substituted with at least one (e.g., 1, 2, 3, or 4) substituents that can each independently be a C.sub.1-9 alkoxy, a C.sub.1-9 haloalkoxy, a nitro (NO.sub.2), a cyano (CN), a C.sub.1-6 alkyl sulfonyl (S(O).sub.2-alkyl), a C.sub.6-12 aryl sulfonyl (S(O).sub.2-aryl)a thiol (SH), a thiocyano (SCN), a tosyl (CH.sub.3C.sub.6H.sub.4SO.sub.2), a C.sub.3-12 cycloalkyl, a C.sub.2-12 alkenyl, a C.sub.5-12 cycloalkenyl, a C.sub.6-12 aryl, a C.sub.7-13 arylalkylene, a C.sub.4-12 heterocycloalkyl, and a C.sub.3-12 heteroaryl instead of hydrogen, provided that the substituted atom's normal valence is not exceeded. The number of carbon atoms indicated in a group is exclusive of any substituents. For example CH.sub.2CH.sub.2CN is a C.sub.2 alkyl group substituted with a nitrile.

(51) While particular embodiments have been described, alternatives, modifications, variations, improvements, and substantial equivalents that are or may be presently unforeseen may arise to applicants or others skilled in the art. Accordingly, the appended claims as filed and as they may be amended are intended to embrace all such alternatives, modifications variations, improvements, and substantial equivalents.