Effect of pretreated acetic acid anhydride and reaction conditions on the black by-product in synthesis of tetraacetylenediamine

Tetraacetylenediamine was synthesized using diacetylenediamine(DAED) with the untreated or pretreated acetic acid anhydride.The effect of reaction temperature,time and the molar ratio of acetic acid anhydride and DAED on the absorbency of product were investigated.The results showed that reaction temperature and time had obvious effect on the generation of black by-product,but the effect of materials ratio was little.Under the condition of temperature 130 ℃,6∶1 of molar ratio of acetic acid anhydride and DAED,over 360 min of reaction time,the absorbency of product synthesized by pretreated acetic acid anhydride,which was pretreated by sulfur trioxide,was less than one fifth of the un-pretreated.Pretreating acetic acid anhydride was a good method to evidently depress the black by-product.