酸处理铌酸对合成2,5-二甲基-2,4-己二烯催化作用的研究

研究了用硝酸、硝酸+磷酸处理的铌酸对制备2,5-二甲基-2,4-己二烯的催化反应活性的影响。并用XRD、原位红外、BET等技术手段考察了它们的结构特征、表面酸性和酸强度。酸处理后的铌酸的催化活性由未处理的18％提高到75％以上,并且相当稳定,寿命也由不到30 h延长到400 h以上,同时括性没有下降趋势。酸处理改变了铌酸的表面酸性和结构特征,孔径明显增大,特别是经硝酸+磷酸处理的铌酸。

Study on Acid Modified Niobic Acid Catalyst for Synthesis of 2,5 - Dimethyl- 2,4- Hexadiene

Treatment of niobic acid with nitric acid and phosphoric acid and its catalytic activity in Prins reaction for 2,5 -dimethyl -2,4 - hexadiene synthesis had been studied. By means of XRD,in situ FTIR and BET,the acid-treated niobic acid was found to be effective in the reaction by changing its surface acid properties and structural character. The catalytic activity was raised from 22% to more than 75% before and after acid treatment. The acid treated catalyst was stable. When reaction time prolonged from 30 h to 400 h,the catalytic activity exhibited no trend of dropping. The pore diameter of acid-treated niobic acid was increased, especially with phosphoric acid.