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US 2010/0160686 A1Published application
Process for the Preparation of Monomers for Polybenzimidazole Materials
AssigneeE. I. Du Pont de Nemours and Company
InventorsJOACHIM C. RITTER, Rajiv Dhawan
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Abstract
A process is provided to produce 2,3,5,6-tetraaminotoluene. Highly pure salts of 2,3,5,6-tetraaminotoluene are produced via reduction of 2,6-diamino-3,5-dinitrotoluene. The 2,3,5,6-tetraaminotoluene salt is precipitated as a clean (>99% purity) product. The salt is a precursor for monomers to make a polybenzimidazole for high performance fibers.
Claims7
A process for preparing 2,3,5,6-tetraaminotoluene
- comprising contacting 2,6-diamino-3,5-dinitrotoluene (II)
- with a hydrogenation catalyst and hydrogen gas, in water in a reaction vessel, to form a reaction mixture, at a pressure in the range of about 0.31 to about 3.45 MPa and a temperature in the range of about 20° C. to about 100° C. to hydrogenate the 2,6-diamino-3,5-dinitrotoluene, thereby producing 2,3,5,6-tetraaminotoluene (I);
- and subsequently filtering the reaction mixture, thereby removing the spent hydrogenation catalyst.
A process for preparing a 2,3,5,6-tetraaminotoluene salt comprising:
- (a) contacting 2,3,5,6-tetraaminotoluene
- with an aqueous solution comprising 1 to 6 equivalents of acid per mol of 2,3,5,6-tetraaminotoluene, optionally heating the solution, thereby dissolving the 2,3,5,6-tetraaminotoluene;
- (b) forming and precipitating the 2,3,5,6-tetraaminotoluene salt by adding an acid to the dissolved 2,3,5,6-tetraaminotoluene;
- and
- (c) washing the 2,3,5,6-tetraaminotoluene salt, wherein all steps are performed under oxygen exclusion.
2 more elements
Dependencies are inferred from the claim text.