Catalyst for and method of preparing cellulose esters
AssigneeEastman Kodak Company
InventorsRichard J. Brewer, Brice S. Wininger
Life of this patent
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Abstract
Disclosed is a catalyst composition and a method of preparing lower fatty acid esters of cellulose which comprises esterifying at a temperature of between about 75.degree. C. and about 110.degree. C. a cellulose compound having esterifiable hydroxyl groups with an esterifying bath comprising an organic acid anhydride, a diluent, and a catalyst comprising from about 25 to about 75% by weight sulfuric acid and about 75 to about 25% by weight phosphoric acid, the catalyst being used in amounts of from about 0.3 to about 0.8% by weight based on the weight of cellulose.
Claims6
A method of preparing lower fatty acid esters of cellulose which comprises esterifying at a temperature of between about 75.degree. C. and about 110.degree. C. a cellulose compound having esterifiable hydroxyl groups with an esterifying bath comprising an organic acid anhydride, a diluent, and from 0.3 to 0.8% by weight based on the weight of cellulose of a catalyst comprising (a) from about 25 to about 75% by weight of sulfuric acid and (b) from about 75% to about 25% by weight of phosphoric acid, the weight ratio of said bath to the cellulose being between about 5:1 and about 10:1.
A method of preparing lower fatty acid ester of cellulose which comprises esterifying at a temperature of between about 85.degree. C. and about 95.degree. C. a cellulose compound having esterifiable hydroxyl groups with an esterifying bath comprising an organic acid anhydride, a diluent, and a catalyst comprising (a) from about 0.2% by weight, based on the weight of cellulose, of sulfuric acid and (b) from about 0.07 to about 0.6% by weight, based on the weight of cellulose, of phosphoric acid, the weight ratio of said bath to the cellulose being between about 5:1 and about 10:1.
Dependencies are inferred from the claim text.