US3763015A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the separation of styrene from thermally cracked petroleum by polymer inhibition and extractive distillation
Assignee: Toray Industries Inc
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Filing: 1971-07-19
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Granted: 1973-10-02
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Expires: 1991-07-19
Abstract
Abstract A process is provided for the separation of styrene from thermally cracked petroleum. In the process of this invention thermally cracked petroleum is initially distilled to recover the fraction boiling between 120*C and 160*C. This fraction is then subjected to extractive distillation with an organic polar solvent containing a nitrite polymerization inhibitor in which the styrene is soluble. The solvent is removed and the styrenecontaining fraction is thereafter treated with nitric acid after which it is scrubbed with water or alkali. The resulting product is fractionated to recover styrene of high purity which is substantially colorless.
Inventors
- 👤 H Morimoto
- 👤 M Tatsumi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 05:52
CPC Classifications
C; C07; C07C; C07C7/00; C07C7/148; C07C7/17; C07C7/005; C07C7/04; C07C7/05; C07C7/08; C07C7/163; C07C7/20
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
16 words
The process according to claim 1 wherein said fraction has a boiling point 135*C and 150*C.
Claim 2
Dependent Claim
45 words
The process according to claim 1 wherein said fraction is hydrogenated in the presence of palladium catalyst having sufficient catalytic activity to promote the hydrogenation of acetylenic impurities in said fraction, but insufficient catalytic activity to cause substantial hydrogenation of the styrene in said fraction.
Claim 3
Dependent Claim
24 words
The process according to claim 1 wherein said polar organic solvent is used in an amount from 0.5-5 times by weight of said fraction.
Claim 4
Dependent Claim
26 words
The process according to claim 1 wherein said polar organic solvent is selected from the group consisting of dimethylacetamide, Beta -methoxypropionitrile, butyllactone, N-methylprrolidone, dimethylformamide and dimethylsulfoxide.
Claim 5
Dependent Claim
28 words
The process according to claim 1 wherein said nitrite is an alkali metal nitrite and is added in said solvent in an amount of at least 50 ppm.
Claim 6
Dependent Claim
30 words
The process according to claim 1 wherein said nitrite is sodium nitrite or potassium nitrite and is Added in said solvent in an amount from about 50 - 5000 ppm.
Claim 7
Dependent Claim
24 words
The process according to claim 1 wherein said styrene is reacted with at least 1 percent of nitric acid based on styrene fraction weight.
Claim 8
Dependent Claim
24 words
The process according to claim 1 wherein said styrene is reacted with 1 - 30 percent of nitric acid based on styrene fraction weight.
Claim 9
Dependent Claim
22 words
The process according to claim 1 wherein said styrene is scrubbed with water and/or an aqueous alkaline solution prior to re-distillation thereof.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-10-01 | 1977-04-02 | 1977-10-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-01 | 1981-04-02 | 1981-10-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-01 | 1985-04-02 | 1985-10-02 | $7700.00 | Window Closed / Lapsed |