Patent ID: 6160111
Filing Date: 2000-12-12
Classification: C08B

Abstract:
A process for preparing cellulose esters having a total DS/AGU of 0.1 to 2.9, said process comprising contacting the following:(i) a cellulose material,(ii) a solubilizing amount of a solvent system for said resultant cellulose esters comprising either a carboxamide diluent or a urea-based diluent,wherein the carboxamide portion of said carboxamide diluent comprises the structure: R.sup.4 R.sup.5 NCOCR.sup.6 R.sup.7 R.sup.8, wherein R.sup.4, R.sup.5, R.sup.6, R.sup.7, and R.sup.8 are independently selected from the group consisting of hydrogen, alkyl having from about 1 to about 20 carbon atoms, branched alkyl having from about 1 to about 20 carbon atoms, phenyl, naphthyl, alkenyl having from about 1 to about 20 carbon atoms, and branched alkenyl having from about 1 to about 20 carbon atoms, andwherein said urea portion of said urea-based diluent comprises the structure: R.sup.9 R.sup.10 NCONR.sup.11 R.sup.12, wherein R.sup.9, R.sup.10, R.sup.11, and R.sup.12 are independently selected from the group consisting of hydrogen, alkyl having from about 1 to about 20 carbon atoms, branched alkyl having from about 1 to about 20 carbon atoms, phenyl, naphthyl, alkenyl having from about 1 to about 20 carbon atoms, and branched alkenyl having from about 1 to about 20 carbon atoms,(iii) an acylating reagent selected from the group consisting of(a) an acid chloride, and optionally, an acid acceptor,(b) a carboxylic acid anhydride,(c) diketene, ketene, 2,2,6-trimethyl-4H-1,3-dioxin-4-one, and an ester of acetoacetic acid,(d) an ester of a carboxylic acid, and combinations of one or more of (a)-(d), and(iv) an insoluble sulfonic acid resin catalyst;wherein said components (i) and (ii) are contacted first and components (iii) and (iv) are contacted with the product of said contacting of components (i) and (ii), in any order,wherein after the contacting step, the resultant cellulose ester has a DS/AGU of from 0.1 to 2.9.