摘要
以NH_3氮化法和甲基硅烷化法等改性方法处理Ti-MCM-41分子筛,并研究了不同改性方法对分子筛结晶度、结构、酸性及疏水性的影响;考察了改性分子筛催化剂对不同来源过氧化氢异丙苯(CHP)催化环氧化丙烯制环氧丙烷(PO)反应的影响。采用XRD、N_2吸附-脱附、FTIR、Py-IR、UV-Vis等表征方法对催化剂结构进行表征。表征结果显示,改性处理会导致分子筛孔道收缩、结晶度降低,但仍具有MCM-41分子筛的六方相孔结构。实验结果表明,NH_3氮化改性的催化剂,由于酸强度降低,能减少CHP无效分解,CHP的利用率由66.1%提高至80.4%;而经甲基硅烷化改性的催化剂,由于表面疏水性的提高,可提高PO的选择性至99.6%。
Mesoporous Ti-MCM–41 molecular sieve was modified through nitridation with NH3 and silylation with trimethylchlorosilane（TMCS） separately,and the effects of the modification methods on the crystallinity,structure,acid strength and hydrophobicity of Ti-MCM–41 were studied by means of XRD,N2 adsorption-desorption,FTIR,Py-IR and UV-Vis. The catalytic performances of the modified Ti-MCM-41 catalysts in the epoxidation of propene with cumene hydroperoxide（CHP） to propylene oxide（PO） were investigated. The characterizations showed that,although the pores shrank and the crystallinity decreased,the ordered and uniform pores on all the catalysts were kept. In the epoxidation on the modified catalyst with NH3,the decreasing of acid strength inhibited the non-productive decomposition of CHP,so the efficiency of CHP could increase from 66.1% to 80.4%. The silylation with TMCS could enhance the hydrophobicity of Ti-MCM-41,so the selectivity to PO reached 99.6%.
出处
《石油化工》
CAS
CSCD
北大核心
2016年第9期1050-1055,共6页
Petrochemical Technology
