Preparation of 5-Chloroformyloxyisophthaloyl Chloride

Triphosgene(BTC) was used as a carbonyl chlorinating agent to prepare 5-chloroformyloxyisophthaloyl chloride(CFIC) from 5-hydroxyisophthalic acid(HIA) in the presence of composite catalysts,and the top yield of CFIC was 42.3%.Effects of reaction conditions on the product yield were discussed.If the mole ratio of BTC to HIA was less than 1.1,few products could be obtained.When the ratio was between 1.1 and 1.7,the higher the ratio,the more the yield.Mole ratio higher than 1.7 hardly affected the yield.The higher polarity the solvent has,the quicker the reaction was.Effect of composite catalysts (triethylamine/imidazole,pyridine/imidazole) was more excellent than the single catalysts (N,N-dimethylformamide,triethylamine,pyridine,imidazole).Low temperature of 5～20 ℃ was suitable to the reaction,and the reaction hardly carried out at temperature higher than 30 ℃.Short reaction time affected the yield obviously,but reaction time longer than 24 h was not neccessary.Suitable preparation technology was obtained by orthogonal tests,i.e.,n(BTC)/n(HIA)=1.67,the composite catalyst n(imidezole)∶n(pyridine)=1∶4,m(BTC)∶m(CATALYST)=1∶0.08,and reaction temperature 5～10 ℃.The main functional groups were analyzed by IR 200.The strong absorption peaks at 1785.24,1764.12,1603.20 and 1557.99 cm~(-1) indicated respectively the function groups Ar—OCOCl,Ar—COCl and 1,3,5-tri substituted benzene ring.Weight percent of the product CFIC was 99.4% as measured by P680 HPLC.The melting point of CFIC was 56.7～57.0 ℃.Reaction mechanism of BTC and effects of the composite catalyst were assumed.