Abstract: Process for the production of polysaccharide ethers, e.g. cellulose ethers, are disclosed wherein salts formed during the process, e.g., sodium nitrate or sodium acetate, are converted to their corresponding acids and bases by means of an electric current, preferably in combination with a bipolar membrane and suitable catiion and/or anion membranes. The acids and bases recovered from the process can be recycled, thereby avoiding the need to provide for disposal of salts.

Abstract: Processes for the production of polysaccharide ethers, e.g. cellulose ethers, are disclosed wherein salts formed during the process, e.g., sodium nitrate or sodium acetate, are converted to their corresponding acids and bases by means of an electric current, preferably in combination with a bipolar membrane and suitable cation and/or anion membranes. The acids and bases recovered from the processes can be recycled, thereby avoiding the need to provide for disposal of the salts.

Abstract: Described herein is an improved process for preparing an ester derivative of a dihydric phenol by reacting the dihydric phenol with an acid anhydride wherein the improvement comprises carrying out the reaction in the presence of a particular adsorbent. Also described herein is a method of treating an ester derivative of a dihydric phenol with a particular adsorbent.

Abstract: Described herein is a process for preparing a polyarylate having a reduced viscosity of from about 0.5 to greater than 1.0 dl/gm which process comprises the following steps:(a) reacting an acid anhydride derived from an aliphatic monocarboxylic acid containing from 2 to 8 carbon atoms with at least one dihydric phenol to form the corresponding diester;(b) after forming the diester, removing by vacuum distillation the bulk of the residual acid anhydride, then adding acetic acid, then vacuum distilling to bring the anhydride concentration to a level low enough to enable the formation of a polymer having a low color and good thermal stability; and(c) reacting said diester with at least one aromatic dicarboxylic acid at a temperature sufficient to form the polyarylate.

Abstract: Color improved polyarylates having a reduced viscosity of from about 0.1 to greater than 1.0 dl/gm produced by a process comprising the following steps:(a) reacting an acid anhydride derived from an acid containing from 2 to 8 carbon atoms with at least one dihydric phenol to form the corresponding diester; and(b) reacting said diester with at least one aromatic dicarboxylic acid at a temperature sufficient to form the polyarylate, wherein the improvement comprises carrying out said process in the presence of a particular solid adsorbent.

Abstract: An improved process for preparing a polyarylate having a reduced viscosity of from about 0.1 to greater than 1.0 dl/gm comprising the following steps:(a) reacting an acid anhydride derived from an acid containing from 2 to 8 carbon atoms with at least one dihydric phenol to form the corresponding diester; and(b) reacting said diester with at least one aromatic dicarboxylic acid at a temperature sufficient to form the polyarylate, wherein the improvement comprises carrying out said process in the presence of a particular solid adsorbent.

Abstract: Described herein is an improved process for preparing a polyarylate having a reduced viscosity of from about 0.5 to greater than 1.0 dl/gm which process comprises the following steps:(a) reacting an acid anhydride derived from an acid containing from 2 to 8 carbon atoms with at least one dihydric phenol to form the corresponding diester; and(b) reacting said diester with at least one aromatic dicarboxylic acid at a temperature sufficient to form the polyarylate, wherein the improvement comprises removing residual acid anhydride, after formation of the dihydric phenol diester, so that its concentration is less than about 1500 parts per million. The novel polyarylates produced by the improved process of this invention are melt stable and low in color.