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US 9,950,996 B2Granted
Bio-based aromatic diisocyanates for preparation of polyurethanes
AssigneeCouncil of Scientific and Industrial Research
InventorsParakash Purushottam Wadgaonkar, Sachin Suresh Kuhire
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Abstract
The present invention provides bio-based aromatic diisocyanate of formula (I). [Formula should be inserted here] wherein X is OCH3, Y is selected from —H or OCH3, and m=0-12. The present invention further provides a method for preparation of aromatic diisocyanate of formula (I) useful for preparation of polyurethane.
Claims9
A bio-based aromatic diisocyanate of formula (I)
- wherein
- X is —OCH3, Y is —H or —OCH3, and
- m=0-12.
A process for the preparation of an aromatic diisocyanate of formula (I)
- wherein
- X is —OCH3, Y is —H or —OCH3, and
- m=0-12,
- comprising the steps of:
- (a) converting a bio-based phenolic acid to the corresponding methyl ester;
- (b) converting 2 equivalents of the methyl ester of step (a) to an aromatic diester by etherification with a dihaloalkane;
- (c) hydrolyzing the aromatic diester of step (b) to the corresponding aromatic diacid;
- (d) converting the aromatic diacid of step (c) to an aromatic diacyl azide;
- and
- (e) converting the aromatic diacyl azide by thermal Curtius rearrangement to obtain the corresponding aromatic diisocyanate of formula (I).
7 more elements
Dependencies are inferred from the claim text.