Patent US4379767A successfully refreshed from Google Patents.
US4379767A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Manufacture of isocyanates
Assignee: Wyeth Holdings LLC
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Filing: 1982-03-08
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Granted: 1983-04-12
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Expires: 2002-03-08
Abstract
Abstract A process for the production of tertiary benzyl isocyanates by reaction of the corresponding olefin with a carbamoyl halide to form the benzyl halide followed by the reaction of the benzyl halide with an excess of isocyanic acid to form the isocyanate and carbamoyl halide which can be recovered and recycled.
Inventors
- 👤 Vazken A. Alexanian
- 👤 Peter S. Forgione
- 👤 Laurence W. Chang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 05:32
CPC Classifications
C; C07; C07C; C07C263/00; C07C263/02
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
130 words
A process for the production of tertiary benzyl isocyanates which comprises reacting a vinyl aromatic compound of the formula: ##STR3## in which: R 1 is an alkylidene group having from 1 to 3 carbon atoms, R 2 is an alkyl group having from 1 to 3 carbon atoms, and R 3 is a phenyl, biphenyl or naphthyl group or a substituted phenyl, biphenyl or naphthyl group having substituents selected from halogen atoms, methyl and methoxy groups and substituents of the formula: ##STR4## with a carbamoyl halide in a solvent for said aromatic compound, carbamoyl halide, isocyanic acid and reaction products thereof to produce the corresponding aromatic halide and reacting said aromatic halide in said solution with isocyanic acid in sufficient excess to form the corresponding aromatic isocyanate and carbamoyl halide.
Claim 2
Dependent Claim
130 words
A process for the production of tertiary benzyl isocyanates which comprises reacting a vinyl aromatic compound of the formula: ##STR3## in which: R 1 is an alkylidene group having from 1 to 3 carbon atoms, R 2 is an alkyl group having from 1 to 3 carbon atoms, and R 3 is a phenyl, biphenyl or naphthyl group or a substituted phenyl, biphenyl or naphthyl group having substituents selected from halogen atoms, methyl and methoxy groups and substituents of the formula: ##STR4## with a carbamoyl halide in a solvent for said aromatic compound, carbamoyl halide, isocyanic acid and reaction products thereof to produce the corresponding aromatic halide and reacting said aromatic halide in said solution with isocyanic acid in sufficient excess to form the corresponding aromatic isocyanate and carbamoyl halide.
Claim 3
Dependent Claim
43 words
A process according to claim 1 in which said reaction of said aromatic halide and isocyanic acid is carried out in the presence of a catalyst effective to promote the reaction of said aromatic halide and isocyanic acid to form said aromatic isocyanate.
Claim 4
Dependent Claim
13 words
A process according to claim 2 in which the catalyst is zinc chloride.
Claim 5
Dependent Claim
15 words
A process according to claim 1, 2 or 3 in which the solvent is toluene.
Claim 6
Dependent Claim
19 words
A process according to claim 1, 2 or 3 in which the vinyl aromatic compound is a diisopropenyl benzene.
Claim 7
Dependent Claim
20 words
A process according to claim 1, 2 or 3 in which the reaction temperature is between -10° and 10° C.
Claim 8
Dependent Claim
17 words
A process according to claim 1, 2 or 3 in which the carbamoyl halide is carbamoyl chloride.
Claim 9
Dependent Claim
17 words
A process according to claim 1, 2 or 3 in which the carbamoyl halide is carbamoyl bromide.
Claim 10
Dependent Claim
28 words
A process according to claim 1, 2 or 3 in which carbamoyl halide and excess isocyanic acid are recovered from the reaction mixture after formation of said isocyanate.
Claim 11
Dependent Claim
17 words
A process according to claim 1, 2 or 3 in which the vinyl aromatic compound is α-methylstyrene.
Claim 12
Dependent Claim
16 words
A process according to claim 1, 2 or 3 in which the vinyl aromatic is diisopropenylnaphthalene.
References Cited (Backward Citations)
US3290350A
Cited
US4130577A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-04-11 | 1986-10-11 | 1987-04-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-04-11 | 1990-10-11 | 1991-04-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-04-11 | 1994-10-11 | 1995-04-12 | $7700.00 | Window Closed / Lapsed |