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US 4,225,505 AGranted
Pyrolysis of N-substituted-1-cyclohexene-1,2-dicarboximides and hydrolysis of product to pyromellitic anhydride
AssigneePhillips Petroleum Company
InventorRaymond L. Cobb
Life of this patent
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Abstract
Pyrolysis of N-substituted-1-cyclohexene-1,2-dicarboximide gives N,N'-substituted-pyromellitdiimides. Pyrolysis of N-substituted-1-cyclohexene-1,2-dicarboximide in the presence of N-substituted maleimides produces N,N'-substituted-3,4,5,6-tetrahydropyromellitdiimide and the Diels-Alder dimer of N-substituted-1,3-butadiene-2,3-dicarboximide.
Claims3
A process for the preparation of pyromellitic anhydride which comprises the steps of pyrolyzing N-phenyl- or N-alkyl-1-cyclohexene-1,2-dicarboximides under pyrolysis conversion conditions to N,N'-diphenyl- or N,N'-dialkyl-substituted-pyromellitdiimides,
- wherein said pyrolysis conversion conditions include elevated temperatures in the range of about 500.degree. C. to 1000.degree. C., reduced pressure, and short contact time, effective for said pyrolysis, and
- solvolyzing under hydrolysis conditions said N,N'-diphenyl- or N,N'-dialkyl-substituted-pyromellitdiimides to said pyromellitic anhydride.
Dependencies are inferred from the claim text.