Oxidized disulfide oil solvent compositions

Abstract

Oxidized disulfide oil (ODSO) solvent compositions are derived from by-product disulfide oil (DSO) compounds produced as by-products from the generalized mercaptan oxidation (MEROX) processing of a refinery feedstock. The oxidized disulfide oil (ODSO) solvent compositions comprise at least a primary oxidized disulfide oil (ODSO) compound selected from either water soluble or water insoluble oxidized disulfide oil (ODSO) compounds and in some embodiments at least 0.1 ppmw of a secondary oxidized disulfide oil (ODSO) compound that is a water soluble oxidized disulfide oil (ODSO) compound.

Claims

1. An oxidized disulfide oil (ODSO) mixture consisting of two or more primary oxidized disulfide oil (ODSO) compounds selected from the group consisting of (RSOSR), (RSOOSR), (RSOOSOR), (RSOOSOOR), (RSOSOR), (RSOSOOOH), (RSOOSOOOH), (RSOSOOH), and (RSOOSOOH), and mixtures thereof, where R and R are alkyl groups each of which comprises from 1-10 carbon atoms, and wherein the ODSO compounds in the mixture correspond to oxidized disulfide oils present in an effluent refinery hydrocarbon stream recovered following the catalytic oxidation of mercaptans present in the hydrocarbon stream.

2. The ODSO mixture of claim 1, wherein the mixture comprises water soluble and water insoluble compounds.

3. The ODSO mixture of claim 1, wherein the mixture has a dielectric constant that is less than or equal to 100 at 0 C.

4. The ODSO mixture of claim 1, wherein the number of oxygen atoms in the two or more primary ODSO compound is in the range of from 1 to 5.

5. The ODSO mixture of claim 1, wherein the disulfide oils are oxidized in the presence of a catalyst.

6. The ODSO mixture of claim 5, wherein the oxidized disulfide oils are formed in the presence of one or more heterogeneous or homogeneous catalysts comprising a metal from IUPAC Groups 4-12 of the Periodic Table.

7. The ODSO mixture of claim 1, wherein the catalyst is sodium tungstate.

8. The ODSO mixture of claim 4, wherein the oxidation of the disulfide oils is carried out in an oxidation vessel selected from one or more of the group consisting of a fixed-bed reactor, an ebullated bed reactor, a slurry bed reactor, a moving bed reactor, a continuous stirred tank reactor, and a tubular reactor.

9. The ODSO mixture of claim 1, wherein the oxidized disulfide oils are formed at a pressure in the range of from about 1 bar to 30 bars.

10. The ODSO mixture of claim 1, wherein the oxidized disulfide oils are formed at a temperature in the range of from about 20 C. to 300 C.

11. The ODSO mixture of claim 1, wherein the oxidized disulfide oils are formed at a molar feed ratio of oxidizing agent-to-mono-sulfur compounds in the range of from about 1:1 to about 100:1.

12. The ODSO mixture of claim 1, wherein the oxidized disulfide oils are formed a residence time of about 5 to 180 minutes.

13. The ODSO mixture of claim 1, that consists of: methylmethanethiosulfonate (H.sub.3CSOOSCH.sub.3); dimethyldisulfoxide (H.sub.3CSOSOCH.sub.3); methylethanethiosulfonate (H.sub.3CSOOSCH.sub.2CH.sub.3); ethylmethyldisulfoxide (H.sub.3CSOSOCH.sub.2CH.sub.3); ethylethanethiosulfonate (H.sub.3CH.sub.2CSOOSCH.sub.2CH.sub.3); and diethyldisulfoxide (H.sub.3CH.sub.2CSOSOCH.sub.2CH.sub.3).

14. An oxidized disulfide oil (ODSO) mixture consisting of the following oxidized disulfide oil (ODSO) compounds: (RSOSR), (RSOOSR), (RSOOSOR), (RSOOSOOR), (RSOSOR), (RSOSOOOH), (RSOOSOOOH), (RSOSOOH), and (RSOOSOOH), where R and R are alkyl groups each of which comprises from 1-10 carbon atoms, and wherein the ODSO compounds in the mixture correspond to oxidized disulfide oils present in an effluent refinery hydrocarbon stream recovered following the catalytic oxidation of mercaptans present in the hydrocarbon stream.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The process for the production and utility of the compositions of this disclosure will be described in more detail below and with reference to the attached figures in which:

(2) FIG. 1 is the experimental GC-MS chromatogram of the non-polar, water insoluble solvent composition, referred to below as Composition 1;

(3) FIG. 2A is the experimental .sup.1H-NMR spectrum of the non-polar, water insoluble solvent composition identified as Composition 1;

(4) FIG. 2B is the experimental .sup.13C-DEPT-135-NMR spectrum of the non-polar, water insoluble solvent composition identified as Composition 1;

(5) FIG. 3 is the simulated .sup.13C-NMR spectrum of dialkyl-thiosulfones;

(6) FIG. 4A is the experimental .sup.1H-NMR spectrum of the polar, water soluble solvent composition, referred to below as Composition 2;

(7) FIG. 4B is the experimental .sup.13C-DEPT-135-NMR spectrum of the polar, water soluble solvent composition identified as Composition 2;

(8) FIG. 5A is the simulated .sup.13C-NMR spectrum of a combination of the alkyl-sulfoxidesulfonate (RSOSOOOH) and alkyl-sulfonesulfonate (RSOOSOOOH), and

(9) FIG. 5B is the simulated .sup.13C-NMR spectrum of a combination of the alkyl-sulfoxidesulfinate (RSOSOOH) and alkyl-sulfonesulfinate (RSOOSOOH).

DETAILED DESCRIPTION OF THE INVENTION

(10) Compositions comprising mixtures of compounds found to have utility for applications such as solvents and lubricity additives can advantageously be produced by the oxidation of a mixture of disulfide oil (DSO) compounds recovered as a low value by-product of the mercaptan oxidation of a hydrocarbon feedstock.

(11) The oxidation reaction can be conducted in any suitable reaction vessel. Examples of suitable vessels include, but are not limited to, one or more fixed-bed reactors, ebullated bed reactors, slurry bed reactors, moving bed reactors, continuous stirred tank reactor, and tubular reactors. In embodiments were a fixed bed is used, the reactor can also comprise a plurality of catalyst beds.

(12) The oxidation reaction can be conducted in batch mode or continuously. The oxidation reaction is an exothermic reaction that raises the temperature of the vessel. In certain embodiments, the oxidation can be carried out in a cooled reactor and/or coupled to a heat exchanger to control and maintain the reaction vessel and reactants at a predetermined temperature. If a heat exchanger is coupled to the system, the excess heat can be recovered for later use. It appears that reducing the temperature of the reaction mixture below a predetermined value, or range, adversely effects the reaction kinetics and the extent of the exothermic reaction and prevents the reaction from going to completion.

(13) In view of the exothermic nature of the oxidation reaction, the oxidant, e.g., hydrogen peroxide, is added to DSO which is initially at room temperature. The temperature of the reaction mixture increases and in an embodiment is maintained at about 80 C. for one hour.

(14) In certain embodiments, the ODSO solvent compounds contain one or more alkyl groups with carbon numbers in the range of from 1 to 10. In certain embodiments, the number of sulfur atoms in the ODSO compounds comprising the solvents are in the range of from 1 to 3. In certain embodiments, the number of oxygen atoms in the ODSO compounds is in the range of from 1 to 5. In a preferred embodiment, the number of carbon atoms in the mixture of ODSO compounds comprising the solvent is in the range of from 1 to 20.

(15) The ODSO solvent compositions of the present disclosure can be soluble or insoluble in oil at the effective or working concentrations. The ODSO solvents produced can be soluble or insoluble in water at the effective or working concentrations, depending on the ratio of DSO-to-oxidant present in the oxidation reaction.

(16) In accordance with the present disclosure, both water soluble and water insoluble ODSO solvents can be produced by controlling the molar ratio of the reactants. For example, an oxidation reaction carried out with a hydrogen peroxide oxidant at a molar ratio of oxidant-to-DSO compounds (calculated based upon mono-sulfur content) of 1.87 produces an ODSO solvent composition comprising 7% water insoluble ODSO compounds and 93% water soluble compounds. An oxidation reaction carried out at a molar ratio of oxidant-to-DSO compounds (calculated based upon mono-sulfur content) of 2.40 produces an ODSO solvent composition comprising 1% water insoluble ODSO compounds and 99% water soluble compounds. An oxidation reaction carried out at a molar ratio of oxidant-to-DSO compounds (calculated based upon mono-sulfur content) of 2.89 produces an ODSO solvent composition comprising substantially no detectable water insoluble ODSO compounds and 100% water soluble compounds.

(17) In these embodiments, any water soluble compounds comprising the solvent will settle to the bottom and form a layer which can be separated from the water insoluble compounds. For example, in certain embodiments, a settler tank can be used in batch or continuous mode for separation. In certain embodiments, two- or three-phase water booth separators known in the art can be used. In general, as the amount of oxidant that is added increases, there is more conversion to the polar, water soluble ODSO solvent.

(18) The ODSO solvent compositions have boiling points in the range of from about 20 C. to 650 C. Water soluble ODSO compounds produced according to the present description generally have boiling points in the range of from about 20 C. to 650 C., while water insoluble ODSO compounds produced according to the present description generally have boiling points in the range of from about 20 C. to 250 C. In certain embodiments, the ODSO compounds have a dielectric constant that is less than or equal to 100 at 0 C.

(19) In general, due to the nature of the reaction for synthesizing the ODSO solvent compositions, even when the ODSO solvent composition is comprised essentially of water soluble ODSO compounds, trace levels of water insoluble ODSO compounds will also be present in the ODSO solvent composition. Similarly, when the ODSO solvent composition is comprised principally of water insoluble ODSO compounds, trace levels of water soluble ODSO compounds will also be present in the ODSO solvent composition. At present, based on experience and knowledge gained from working with the present reaction mechanisms, and tests and analyses conducted, the trace levels of either of the respective water insoluble or water soluble ODSO compounds present is in the range of from about 0.1 ppmw to 10 ppmw.

EXAMPLES

(20) In the following examples, ODSO compounds were produced by the catalytic oxidation of samples of disulfide oil (DSO) compounds recovered as a by-product of the mercaptan oxidation of a hydrocarbon refinery feedstock. The feed used in the following examples was composed of 98 W % of C1 and C2 disulfide oils.

(21) The oxidation of the DSO compounds was performed in batch mode under reflux at atmospheric pressure, i.e., at approximately 1.01 bar. The hydrogen peroxide oxidant was added at room temperature, i.e., approximately 23 C. and produced an exothermic reaction. The molar ratio of oxidant-to-DSO compounds (calculated based upon mono-sulfur content) was 2.40. After the addition of the oxidant was complete, the reaction vessel temperature was set to reflux at 80 C. for approximately one hour.

(22) Two immiscible layers formed, one a dark red to brown layer, hereinafter referred to as Composition 1, and a light-yellow layer, hereinafter referred to as Composition 2. A separating funnel was used to separate and isolate each of the two layers.

(23) The catalyst used in the examples described below was sodium tungstate.

Example 1

(24) FIG. 1 depicts the experimental GC-MS chromatogram for a non-polar water insoluble ODSO solvent (Composition 1) of the present invention. The GC-MS spectra shows that the following compounds were present in the ODSO solvent of Composition 1: Peak 1methylmethanethiosulfonate (H.sub.3CSOOSCH.sub.3); Peak 2dimethyldisulfoxide (H.sub.3CSOSOCH.sub.3); Peak 3methylethanethiosulfonate (H.sub.3CSOOSCH.sub.2CH.sub.3); Peak 4ethylmethyldisulfoxide (H.sub.3CSOSOCH.sub.2CH.sub.3); Peak 5ethylethanethiosulfonate (H.sub.3CH.sub.2CSOOSCH.sub.2CH.sub.3); and Peak 6diethyldisulfoxide (H.sub.3CH.sub.2CSOSOCH.sub.2CH.sub.3).

(25) Trace levels of ODSO compounds comprising 3+ oxygen atoms (not shown in the GC-MS data) are also present. It is clear from the GC-MS chromatogram shown in FIG. 1 that Composition 1 comprises a mixture of ODSO compounds that form the ODSO solvent composition.

(26) FIG. 2A is the experimental .sup.1H-NMR spectrum for the non-polar water insoluble ODSO solvent (Composition 1).

(27) FIG. 2B is the experimental (as distinguished from simulated) .sup.13C-DEPT-135-NMR spectrum for Composition 1. Composition 1 was mixed with a CD.sub.3OD solvent and the spectrum was taken at 25 C. The DEPT (Distortionless Enhancement of Polarization Transfer) technique provides reliable information on attached protons in the sample efficiently and with high selectivity. The DEPT technique is a proton-carbon polarization transfer method and provides selective identification of methyl and/or methylene carbon atoms not available by other analytical techniques. In a DEPT-135 spectrum, CH.sub.3 and CH signal peaks show positive intensities while CH.sub.2 signal peaks are shown as negative intensities. In the spectrum in FIG. 2B, methyl carbons will have a positive intensity while methylene carbons exhibit a negative intensity. The peaks in the 48-50 ppm region belong to carbon signals of the CD.sub.3OD solvent.

(28) In order to accurately identify spectral features in .sup.13C-135-DEPT-NMR spectra, such as the one in FIG. 2b, and in order to categorize the corresponding ODSO compounds in the ODSO solvent compositions, .sup.13C-NMR predictions (computational simulations) were carried out using ACDLabs software for the following families of possible ODSO compounds: dialkyl-thiosulfoxides (RSOSR); dialkyl-thiosulfones (RSOOSR); dialkyl-sulfonesulfoxide (RSOOSOR); dialkyl-disulfone (RSOOSOOR); dialkyl-disulfoxide (RSOSOR); alkyl-sulfoxidesulfonate (RSOSOOOH); alkyl-sulfonesulfonate (RSOOSOOOH); alkyl-sulfoxidesulfinate (RSOSOOH); alkyl-sulfonesulfinate (RSOOSOOH); alkyl-sulfoxidesulfenate (RSOSOH); alkyl-thiosulfonates (RSSOOOH); alkyl-thiosulfinates (RSSOOH); and esters (XSOOR or XSOOOR, where X=RSO or RSOO).

(29) The .sup.13C-NMR predictions for the families of possible OSDO compounds were saved in a database for comparison to experimental data. Since the DSO feed contained C1 and C2 hydrocarbons, predictions were carried out for ODSO solvents where R=C1 and C2 alkyls.

(30) When comparing the experimental .sup.13C-135-DEPT-NMR spectrum for Composition 1 (FIG. 2b) with the saved database of predicted spectra, it was found that the predicted dialkly-thiosulfone (RSOOSR) spectrum mostly closely corresponded to the experimental spectrum. This suggests that dialkly-thiosulfones (RSOOSR), where R=C1 and C2 alkyls, are major compounds in Composition 1. This result is complementary to the GC-MS data shown in FIG. 1. The predicted dialkly-thiosulfone (RSOOSR) spectrum is shown in FIG. 3.

(31) The simulated .sup.13C-NMR spectrum in FIG. 3 for Composition 1 corresponds well with the experimental .sup.13C-DEPT-135-NMR spectrum, suggesting the identified compound is present in Composition 1. It is clear from the NMR spectra shown in FIGS. 2a, 2b and 3 that Composition 1 comprises a mixture of ODSO compounds that form the ODSO solvent.

Example 2

(32) FIG. 4a is the experimental .sup.1H-NMR spectrum for a polar water-soluble ODSO solvent composition identified as Composition 2.

(33) FIG. 4b is the experimental .sup.13C-DEPT-135-NMR spectrum for Composition 2. Composition 2 was mixed with a CD.sub.3OD solvent and the spectrum was taken at 25 C. Similar to the peaks in FIG. 2b, in FIG. 4b methyl carbons have a positive intensity while methylene carbons exhibit a negative intensity. The peaks in the 48-50 ppm region belong to carbon signals of the CD.sub.3OD solvent.

(34) When comparing the experimental .sup.13C-135-DEPT-NMR spectrum of FIG. 4b for Composition 2 with the saved database of predicted spectra, it was found that a combination of the predicted alkyl-sulfoxidesulfonate (RSOSOOOH), alkyl-sulfonesulfonate (RSOOSOOOH), alkyl-sulfoxidesulfinate (RSOSOOH) and alkyl-sulfonesulfinate (RSOOSOOH) most closely corresponded to the experimental spectrum. This suggests that alkyl-sulfoxidesulfonate (RSOSOOOH), alkyl-sulfonesulfonate (RSOOSOOOH), alkyl-sulfoxidesulfinate (RSOSOOH) and alkyl-sulfonesulfinate (RSOOSOOH) are major compounds in Composition 2. The combined predicted alkyl-sulfoxidesulfonate (RSOSOOOH) and alkyl-sulfonesulfonate (RSOOSOOOH) spectrum is shown in FIG. 5a. The combined predicted alkyl-sulfoxidesulfinate (RSOSOOH) and alkyl-sulfonesulfinate (RSOOSOOH) spectrum is shown in FIG. 5b.

(35) The simulated .sup.13C-NMR spectrum in FIGS. 5a and 5b of Composition 2 corresponds well to the experimental .sup.13C-DEPT-135-NMR spectrum, suggesting the identified compounds are present in Composition 2. It is clear from the NMR spectra shown in FIGS. 4a, 4b, 5a and 5b that Composition 2 comprises a mixture of ODSO compounds that form the ODSO solvent composition.

(36) It is made clear by the results of the above analyses of Compositions 1 and 2 that ODSO compounds were present.

Example 3

(37) In order to demonstrate its solvent effect, a comparative example of the use of the ODSO solvents of the present disclosure in an aromatic extraction process was conducted. An n-dodecane stock solution to which BTX was added was prepared for use as a feedstock for the extraction of aromatics using (1) a sulfolane solvent and (2) a water-soluble oxidized disulfide oil (ODSO) solvent. The number of carbon atoms in the individual water soluble OSDO compounds of the ODSO solvent used in this comparative example was in the range of from 2 to 4 carbon atoms. The prepared feedstock contained approximately 5 wt. % of benzene, 5 wt. % of toluene, 5 wt. % of o-xylene, 5 wt. % of m-xylene and 5 wt. % of p-xylene, as indicated in Table 2.

(38) TABLE-US-00002 TABLE 2 Sulfolane Extraction (wt. %) ODSO Extraction (wt. %) Normalized Normalized Stock Extract Selectivity Stock Extract Selectivity Benzene 4.12 0.69 100 4.49 0.26 100 Toluene 4.4 0.37 50 4.95 0.02 7 m- 4.81 0.58 72 5.08 0 0 Xylene p-Xylene 4.67 0.21 27 4.95 0 0 o-Xylene 4.66 0.09 12 4.93 0.06 21

(39) The feedstock and the respective solvents were added to separate flasks and vigorously shaken for 10 minutes at room temperature and atmospheric pressure. After mixing, in both cases two distinct phases separated and were isolated. The raffinate layer comprised the feedstock with a portion of its aromatics removed. The extract layer comprised the solvent with the portion of aromatics removed from the feedstock.

(40) Table 2 indicates the results of a GC-MS analysis showing the wt. % of the BTX in the extract layer. When the selectivity is normalized to the benzene extracted, the data indicates that the sulfolane solvent extracts some of each of the other components in varying amounts. In contrast, the results in Table 2 indicate that the water soluble ODSO solvent has high selectivity for benzene, and significantly lower selectivity for toluene and o-xylene, with no measurable removal of the m- and p-xylene from the prepared feedstock.

(41) It is clear from Table 2 that in embodiments where the targeted aromatic compound is benzene, a preferred aromatic extraction solvent is one or a mixture of ODSO compounds used alone, i.e., without other types of solvents.

(42) The compositions of the present invention and method for their preparation have been described above and characterized in the attached figures; however, process modifications and variations will be apparent to those of ordinary skill in the art and the scope of protection for the invention is to be defined by the claims that follow.