Carboxylic acid anhydrides: aliphatic from 1,2-dicarboxylic acids

A dispersant that can be used in drilling fluids, spacer fluids, cement slurries, completion fluids, and mixtures of drilling fluids and cement slurries controls the rheologic properties of and enhances the filtrate control in these fluids. The dispersant consists of polymers derived from monomeric residues, including low-molecular-weight olefins that may be sulfonated or phosphonated, unsaturated dicarboxylic acids, ethylenically unsaturated anhydrides, unsaturated aliphatic monocarboxylic acids, vinyl alcohols and diols, and sulfonated or phosphonated styrene. The sulfonic acid, phosphonic acid, and carboxylic acid groups on the polymers may be present in neutralized form as alkali metal or ammonium salts [192,193]. 

Diorgano tellurium dicarboxylates were prepared from dialkyl and diaryl tellurium derivatives. Aliphatic carboxylic acids, aromatic carboxylic acids, their sodium or silver salts, and carboxylic acid anhydrides were used as reagents. Dicarboxylic acids such as succinic acid and phthalic acid were reported to give monomeric carboxylates when... 

Anhydrides of carboxylic acids are best prepared by the classical method of treating acid chlorides with salts of acids, a method that can be used equally for preparing mixed anhydrides. The salt may be replaced by the free acid if pyridine is added to the reaction mixture. Further, water may be removed directly from carboxylic acids, either by heat in certain cases where aliphatic or aromatic dicarboxylic acids give cyclic anhydrides, or by means of acetic anhydride or acetyl chloride. 

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