Synthesis Of Triphenylamine And Its Derivatives Enhanced By Microwave

Triphenylamine and its derivatives are important raw materials that can be producedelectric charges transport materials and electroilluminant materials. They are also used asorganic dyestuffs and pharmaceutical intermediates. Synthesis of triphenylamine and4,4'-dimethyltriphenylamine and 4,4',4"-trinitrotriphenylamine enhanced by microwave wasinvestigated in this paper. The better technological conditions have been obtained via theexperiments and the products have been characterized.The better technological conditions of triphenylamine's synthesis have been obtained,i.e. diphenylamine and bromobenzene as the raw materials, dimethyl sulfoxide as the solvent,potassium tert-butoxide as the alkali, the molar ratio of diphenylamine, bromobenzene andpotassium tert-butoxide was 1:2:2, hermetical experiments were used under microwaveirradiation, the microwave power was 125W, the reactive time was 20 min, the reactivetemperature was 136 . The molar yield of the product could reach 98.7% under thistechnological conditions.The better technological conditions of 4,4'-dimethyltriphenylamine,s synthesis havebeen obtained, i.e. 4,4'-dimethyldiphenylamine and bromobenzene as the raw materials,dimethyl sulfoxide as the solvent, potassium tert-butoxide as the alkali, the molar ratio of4,4'-dimethyldiphenylamine,bromobenzene and potassium tert-butoxide was 1:2:2, hermeticalexperiments were used under microwave irradiation, the microwave power was 100W, thereactive time was 60 min, the reactive temperature was 175 . The molar yield of the productcould reach 69.5% under this technological conditions.The better technological conditions of 4,4',4"-trinitrotriphenylamine's synthesis havebeen obtained, i.e. p-nitroaniline and 4-chloronitrobenzene as the raw materials, dimethylsulfoxide as the solvent, potassium tert-butoxide as the alkali, the molar ratio of p-nitroaniline,4-chloronitrobenzene and potassium tert-butoxide was 1:3:2, hermetical experiments were used under microwave irradiation, the microwave power was 125W, the reactive time was 20min, the reactive temperature was 115 . The molar yield of the product could reach 98.2%under this technological conditions.It was showed that the triphenylamine's derivatives which its phenyls connected thedonor substitutions were harder to be synthesized than the t riphenylamine and thetriphenylamine's derivatives which its phenyls connected the acciptor substitutions wereeasier to be synthesized than the triphenylamine under mircomave irradiation by theexperimental results. It was also showed that the C N cross-coupling Ullmann reaction waseasy to be processed when the halobenzen which their halogen's radius was big as rawmaterial under mircomave irradiation by the experimental results. The laws on the microwaveare the same as the conventional conditions'.The iodobenzene which was used in the traditional methods was replaced by thebromobenzene/chlorobenzene in the synthesis of triphenylamine and 4,4'-dimethyltri-phenylamine, so the cost of raw materials was greatly reduced. At the same time, the reactivetime was greatly reduced by the advanced microwave irradiation's method. This method alsohas many advantages, such as pure products, few catalysts, easy post processing, easyoperation, safety, little pollution and so on. There had instructional effects for theindustrialization of triphenylamine and its derivatives.