Terephthaloyl chloride dicarboxylic acid

The synthesis of optically active polyamides, or nylons, is a growing area of interest. From 1980 to 1991 there have been many citations in Chemical Abstracts on this subject. For example, optically active polyamides have been prepared for the resolution of optical isomers. The polyamides are prepared from optically active amines or dicarboxylic acids. One polyamide was prepared from (-)-(ram-l,2-diaminocyclohexane and terephthaloyl chloride and was used to resolve 2,2 -dihydroxy-6,6 -dimethylbiphenyl [31]. These optically active polyamides can be used in chromatography applications to resolve other optically active compositions. 

Terephthaloyl chloride (TCI) and isophthaloyl chloride (ICl) are produced by reacting the corresponding dicarboxylic acid with phosgene [43]. 

The polycondensation of a diol and the diester of a dicarboxylic acid (e.g., the dimethyl ester) can be carried out in the melt at a considerably lower temperature than for the corresponding reaction of the free acid. Under the influence of acidic or basic catalysts a transesterification occurs with the elimination of the readily volatile alcohol (see Example 4.3). Instead of diesters of carboxylic acids one can also use their dicarboxylic acid chlorides, for example, in the synthesis of high-melting aromatic polyesters from terephthaloyl dichloride and bisphenols. The commercially very important polycarbonates are obtained from bisphenols and phosgene, although the use of diphenyl carbonate as an alternative component is of increasing interest (see Example 4.4). Instead of free acids, cyclic carboxylic... 

For example, the method for production of aromatic polyketones by means of Friedel-Craft polycondensation of bis (arylsilanes) with chlorides of aromatic dicarboxylic acids (isophthaloyl-,terephthaloyl-,4,4 -oxydibenzoylchloride) at 20 °C in environment of dissolvent (1,2-dichlor-ethane) in the presence of aluminum chloride is proposed in Ref [331], The polyketones have the intrinsic viscosity more than 0.37 deciliter/gram (at 30 °C, in concentrated H SO ), glass transition temperature is 120-231 °C and melting point lies within 246-367 °C. The polyketones start decomposing at a temperature of 400 °C, the temperature of 10% loss of mass is 480-530 °C. 

Dicarboxylic acids found in polymeric esters unsaturated aliphatic acids determined in the ultraviolet by use of the strong bathochromic shift which occurs when concentrated H2SO4 is used as solvent e.g., crotonia acid has a maximum at 220 m/x in water, 235 m/x in H2SO4 Mixtures of terephthaloyl and isophthaloyl chlorides determined in ultraviolet region in iso-octane solution [ ]. 

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