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US 4,056,542 AGranted
Pyrolysis of N-substituted-1-cyclohexene-1,2-dicarboximides
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.
Claims7
A process of preparing pyromellitic anhydride which comprises the steps of:
- reacting under pyrolysis conditions at elevated temperatures in the range of about 500.degree. to 1000.degree. C. at reduced pressure and short contact time N-alkyl-1-cyclohexene-1,2-dicarboximide and N-alkylmaleimide in substantially equimolar relationship thereby producing N,N'-dialkyl-3,4,5,6-tetrahydropyromellitdiimide,
- dehydrogenating said N,N'-dialkyl-3,4,5,6-tetrahydropyromellitdiimide by heating with sulfur, or with a palladium, platinum, or ruthenium dehydrogenation catalyst to N,N'-dialkylpyromellitdiimide, and
- hydrolyzing said N,N'-dialkylpyromellitdiimide, thereby preparing said pyromellitic anhydride.
Dependencies are inferred from the claim text.