Patent US4082787A successfully refreshed from Google Patents.
US4082787A
Expired / Lapsed
US
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Methyl isocyanate process
Assignee: EIDP Inc
•
Filing: 1977-01-03
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Granted: 1978-04-04
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Expires: 1997-01-03
Abstract
Abstract Process for making methyl isocyanate comprising thermally dehydrochlorinating a solution of methyl carbamyl chloride in an aprotic nonpolar solvent, condensing the gases thereby formed at a temperature above the boiling point of methyl isocyanate so as to liquify at least part of said gases which are condensable at said temperature, removing HCl gas by condensing the remaining condensable gases at a temperature below the boiling point of methyl isocyanate, and separating methyl isocyanate from the condensate obtained in said first condensation step.
Inventors
- 👤 Robert James Bassett
- 👤 Walter John Cordes
- 👤 Julius Jakob Fuchs
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 05:51
CPC Classifications
C; C07; C07C; C07C263/00; C07C263/04
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
132 words
A process for making methyl isocyanate comprising thermally dehydrochlorinating a solution of methyl carbamyl chloride in an aprotic non-polar solvent at a temperature above the boiling point of methyl carbamyl chloride; initially condensing the reaction gases thereby formed at a temperature above the boiling point of methyl isocyanate so as to liquify at least part of the gases which are condensable at said temperature and thereby provide an initial liquid condensate consisting essentially of a solution of methyl isocyanate and methyl carbamyl chloride in said solvent wherein the ratio of methyl isocyanate to methyl carbamyl chloride is greater than it is in said reaction solution; separating said initial liquid condensate from the gases remaining after said initial condensation; separating methyl isocyanate from said initial condensate; and separating HCl from said remaining gases.
Claim 2
Dependent Claim
132 words
A process for making methyl isocyanate comprising thermally dehydrochlorinating a solution of methyl carbamyl chloride in an aprotic non-polar solvent at a temperature above the boiling point of methyl carbamyl chloride; initially condensing the reaction gases thereby formed at a temperature above the boiling point of methyl isocyanate so as to liquify at least part of the gases which are condensable at said temperature and thereby provide an initial liquid condensate consisting essentially of a solution of methyl isocyanate and methyl carbamyl chloride in said solvent wherein the ratio of methyl isocyanate to methyl carbamyl chloride is greater than it is in said reaction solution; separating said initial liquid condensate from the gases remaining after said initial condensation; separating methyl isocyanate from said initial condensate; and separating HCl from said remaining gases.
Claim 3
Dependent Claim
19 words
The process of claim 1 wherein methyl carbamyl chloride constitutes between 20% and 50% by weight of said solution.
Claim 4
Dependent Claim
34 words
The process of claim 2 wherein said solvent minimizes side reactions and has a boiling point sufficiently high so as to favor thermal dissociation of methyl carbamyl chloride and fractionation of methyl isocyanate therefrom.
Claim 5
Dependent Claim
25 words
The process of claim 3 wherein from about 25% to about 95% by volume of said condensable gases are liquified in said initial condensation step.
Claim 6
Dependent Claim
10 words
The process of claim 4 wherein said solvent is toluene.
Claim 7
Dependent Claim
20 words
The process of claim 5 wherein methyl carbamyl chloride constitutes between about 35% and 45% by weight of said solution.
Claim 8
Dependent Claim
19 words
The process of claim 6 wherein said thermal dehydrochlorination step is performed at temperatures between 95° and 105° C.
Claim 9
Dependent Claim
21 words
The process of claim 7 wherein said initial condensate has an exit temperature in the range between 50° and 70° C.
Claim 10
Dependent Claim
22 words
The process of claim 8 wherein said solution of methyl carbamyl chloride is continuously dehydrochlorinated and methyl isocyanate is continuously recovered therefrom.
Claim 11
Dependent Claim
21 words
The process of claim 9 wherein said initial condensate has an exit temperature in the range between 55° and 65° C.
Claim 12
Dependent Claim
17 words
The process of claim 4 wherein at least 50% by volume of said condensable gases are liquified.
Claim 13
Dependent Claim
10 words
The process of claim 11 wherein said solvent is toluene.
Claim 14
Dependent Claim
20 words
The process of claim 12 wherein methyl carbamyl chloride constitutes between about 35% and 45% by weight of said solution.
Claim 15
Dependent Claim
19 words
The process of claim 13 wherein said thermal dehydrochlorination step is performed at temperatures between 95° and 105° C.
Claim 16
Dependent Claim
21 words
The process of claim 14 wherein said initial condensate has an exit temperature in the range between 50° and 70° C.
Claim 17
Dependent Claim
22 words
The process of claim 15 wherein said solution of methyl carbamyl chloride is continuously dehydrochlorinated and methyl isocyanate is continuously recovered therefrom.
Claim 18
Dependent Claim
21 words
The process of claim 16 wherein said initial condensate has an exit temperature in the range between 55° and 65° C.
Claim 19
Dependent Claim
17 words
The process of claim 11 wherein 75% to 90% by volume of said condensable gases are liquified.
Claim 20
Dependent Claim
10 words
The process of claim 18 wherein said solvent is toluene.
Claim 21
Dependent Claim
19 words
The process of claim 19 wherein methyl carbamyl chloride constitutes between 35% and 45% by weight of said solution.
Claim 22
Dependent Claim
20 words
The process of claim 20 wherein said thermal dehydrochlorination step is performed at temperatures at between 95° and 105° C.
Claim 23
Dependent Claim
21 words
The process of claim 20 wherein said initial condensate has an exit temperature in the range between 50° and 70° C.
Claim 24
Dependent Claim
22 words
The process of claim 22 wherein said solution of methyl carbamyl chloride is continuously dehydrochlorinated and methyl isocyanate is continuously recovered therefrom.
Claim 25
Dependent Claim
21 words
The process of claim 23 wherein said initial condensate has an exit temperature in the range between 55° and 65° C.
References Cited (Backward Citations)
US3388145A
Cited
US3969389A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-04-03 | 1981-10-03 | 1982-04-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-04-03 | 1985-10-03 | 1986-04-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-04-03 | 1989-10-03 | 1990-04-04 | $7700.00 | Window Closed / Lapsed |