US4265735A
Expired / Lapsed
US
⏱️ 0.0 years remaining
ZSM-5 Zeolite catalyzes dialkyl disulfide conversion to hydrogen sulfide
Assignee: Mobil Oil AS
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Filing: 1979-12-21
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Granted: 1981-05-05
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Expires: 1999-12-21
Abstract
Abstract Dialkyl disulfide waste, such as that formed in a caustic wash process for removing mercaptans from a hydrocarbon stream, is converted to hydrogen sulfide and valuable hydrocarbons by catalytic contact with a highly siliceous zeolite catalyst exemplified by ZSM-5. The hydrogen sulfide in turn is readily converted to marketable sulfur, thus alleviating the waste disposal problem.
Inventors
- 👤 Costandi A. Audeh
- 👤 Clarence D. Chang
- 👤 William H. Lang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 21:56
CPC Classifications
C; C07; C07C; C07C1/00; C07C1/32; C07C1/321; C07C1/322; C01; C01B; C01B17/00; C01B17/16; C01B17/165; C07C7/00; C07C7/148; C07C2529/00; C07C2529/04; C07C2529/06; C07C2529/40
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
120 words
A method for disposing of a liquid stream consisting of a mixture of dialkyl disulfides wherein the alkyl groups individually have from one to about four carbon atoms, which method comprises contacting said stream under a combination of conditions that include a temperature of about 600° F. (305° C.) to about 1000° F. (538° C.), a liquid hourly space velocity of about 0.2 LHSV to about 20 LHSV, and a pressure of about 15 psig to 300 psig, with a crystalline zeolite catalyst having a silica to alumina ratio of at least 12 and a Constraint Index of 1 to 12, said combination of conditions being effective to convert said dialkyl disulfides to hydrogen sulfide and a mixture of hydrocarbons.
Claim 2
Independent Claim
120 words
A method for disposing of a liquid stream consisting of a mixture of dialkyl disulfides wherein the alkyl groups individually have from one to about four carbon atoms, which method comprises contacting said stream under a combination of conditions that include a temperature of about 600° F. (305° C.) to about 1000° F. (538° C.), a liquid hourly space velocity of about 0.2 LHSV to about 20 LHSV, and a pressure of about 15 psig to 300 psig, with a crystalline zeolite catalyst having a silica to alumina ratio of at least 12 and a Constraint Index of 1 to 12, said combination of conditions being effective to convert said dialkyl disulfides to hydrogen sulfide and a mixture of hydrocarbons.
Claim 3
Dependent Claim
21 words
The method described in claim 1 wherein said liquid stream has a sulfur content of about 10 to about 60 wt.%.
Claim 4
Dependent Claim
39 words
The method described in claim 1 wherein said contacting conditions include a temperature of about 700° F. (371° C.) to about 900° F. (482° C.), and said liquid hourly space velocity is about 0.5 LHSV to about 5 LHSV.
Claim 5
Dependent Claim
21 words
The method described in claim 3 wherein said liquid stream has a sulfur content of about 10 to about 60 wt.%.
Claim 6
Dependent Claim
12 words
The method described in claim 1 wherein said crystalline zeolite is HZSM-5.
Claim 7
Dependent Claim
12 words
The method described in claim 2 wherein said crystalline zeolite is HZSM-5.
Claim 8
Dependent Claim
12 words
The method described in claim 3 wherein said crystalline zeolite is HZSM-5.
Claim 9
Dependent Claim
12 words
The method described in claim 4 wherein said crystalline zeolite is HZSM-5.
Claim 10
Dependent Claim
43 words
The method described in claim 1 or claim 2 or claim 3 or claim 4 or claim 5 or claim 6 or claim 7 or claim 8 wherein at least 90 wt.% of said dialkyl disulfides are converted to hydrogen sulfide and hydrocarbons.
Claim 11
Dependent Claim
175 words
In a process for reducing the sulfur content of a hydrocarbon contaminated by one or more aliphatic mercaptans wherein the alkyl group has from one to about four carbon atoms, said process comprising treating said hydrocarbon with an aqueous caustic wash thereby dissolving said mercaptans in said caustic wash, separating said mercaptan-containing caustic wash from said hydrocarbon, oxidizing said mercaptans in said wash thereby forming aliphatic disulfides waste insoluble in said caustic wash and regenerating said caustic wash, separating wash and disposing of said waste, the improvement which comprises: disposing of said aliphatic disulfides waste by contacting the same with a crystalline zeolite catalyst having a silica to alumina ratio of at least 12 and a Constraint Index of 1 to 12, said contacting being effected at a temperature of about 600° F. (305° C.) to about 1000° F. (538° C.) and a liquid hourly space velocity of about 0.2 LHSV to about 20 LHSV thereby converting said disulfide waste to hydrogen sulfide and a mixture of hydrocarbons, and converting said hydrogen sulfide to sulfur.
Claim 12
Dependent Claim
175 words
In a process for reducing the sulfur content of a hydrocarbon contaminated by one or more aliphatic mercaptans wherein the alkyl group has from one to about four carbon atoms, said process comprising treating said hydrocarbon with an aqueous caustic wash thereby dissolving said mercaptans in said caustic wash, separating said mercaptan-containing caustic wash from said hydrocarbon, oxidizing said mercaptans in said wash thereby forming aliphatic disulfides waste insoluble in said caustic wash and regenerating said caustic wash, separating wash and disposing of said waste, the improvement which comprises: disposing of said aliphatic disulfides waste by contacting the same with a crystalline zeolite catalyst having a silica to alumina ratio of at least 12 and a Constraint Index of 1 to 12, said contacting being effected at a temperature of about 600° F. (305° C.) to about 1000° F. (538° C.) and a liquid hourly space velocity of about 0.2 LHSV to about 20 LHSV thereby converting said disulfide waste to hydrogen sulfide and a mixture of hydrocarbons, and converting said hydrogen sulfide to sulfur.
Claim 13
Dependent Claim
13 words
The method described in claim 10 wherein said crystalline zeolite catalyst is HZSM-5.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-05-04 | 1984-11-03 | 1985-05-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-05-04 | 1988-11-03 | 1989-05-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-05-04 | 1992-11-03 | 1993-05-05 | $7700.00 | Window Closed / Lapsed |