H_2O_2处理对HZSM-5分子筛结构及催化环己烯水合性能的影响

Effects of H202 treatment on structure and catalytic performance of HZSM-5 molecular sieves for hydration of cyclohexene

利用H_2O_2对HZSM-5分子筛进行处理,并采用X射线衍射、N_2低温吸附、扫描电子显微镜、NH_3-TPD和吡啶吸附-脱附红外光谱等方法进行表征。考察H_2O_2处理对HZSM-5结构以及催化环己烯水合反应活性的影响。结果表明,处理后分子筛的颗粒变小,颗粒尺寸(0.5～0.7)μm,酸量下降,L酸中心数减少,B酸增强。H_2O_2处理有利于提高催化环己烯水合制备环己醇的反应活性,环己烯转化率和环己醇选择性分别可达8.33%和97.80%。

HZSM-5 molecular sieves treated with H2O2 was characterized by means of XRD,N2 adsorp- tion, SEM, NH3-TPD and Py-FTIR. The effects of H2O2 treatment on the structure and catalytic performance of HZSM-5 molecular sieves for hydration of cyclohexene were investigated. The results showed that particle size of HZSM-5 treated by H2O2 decreased to （0.5 -0.7 ） μm;the number of acid sites of H2O2- HZSM-5 molecular sieves was reduced; the number of Lewis acid sites decreased and the number of Bronsted acid sites increased. The catalytic activity of HZSM-5 molecular sieves treated with H2O2 for hydration of cyclohexene was enhanced. The conversion of cyclohexene and selectivity to cyclohexanol reached 8.33% and 97.80% ,respectively.