Cu-HMS分子筛的合成条件及其催化性能

Synthesis Conditions and Catalytic Performance of Hexagonal Mesoporous Silica Containing Copper

以十二胺 (DDA)为模板剂 ,正硅酸乙酯 (TEOS)为硅源 ,在中性介质中于室温条件下合成了含Cu的中孔杂原子分子筛Cu HMS .在 85℃及常压下 ,以异丙苯氧化 (O2 为氧化剂 )为探针反应考察了Cu源、Cu/Si摩尔比、DDA/TEOS摩尔比和晶化时间等合成条件对分子筛催化氧化性能的影响 .实验结果发现 ,在Cu/Si摩尔比为 0 0 2～ 0 0 3,DDA/TEOS摩尔比为 0 1～0 3,晶化时间为 1h以上 ,Cu源为Cu(NO3 ) 2 的条件下得到的Cu HMS分子筛催化活性最高 .用XRD ,2 9SiMASNMR ,FT IR ,低温N2 吸附和原子发射光谱 (ICP)等手段对催化活性最高的分子筛样品的结构及表面性质进行了表征 ,证明该分子筛具有典型的HMS结构 。

Copper containing hexagonal mesoporous silica (Cu HMS) was synthesized by using neutral dodecylamine (DDA) as template and tetraethyl orthosilicate (TEOS) as Si source in neutral solution and at ambient temperature. The influences of the Cu source, Cu/Si ratio, DDA/TEOS ratio and crystallization time on the catalytic performance of Cu HMS for the cumene oxidation at 85 ℃ and atmospheric pressure using O 2 as oxidant were studied. The results showed that the highest catalytic activity was achieved when the Cu HMS molecular sieve was synthesized with Cu(NO 3) 2 at Cu/Si ratios in the range 0 02～0 03, DDA/TEOS ratios in the range 0 1～0 3 and crystallization time more than 1 h. The cumene conversion, cumene hydroperoxide yield and selectivity for the cumene oxidation using 0 45 g Cu HMS catalyst per 10 ml cumene after 9 h were 39 6%, 39 0% and 98 5%, respectively. The sample with the highest catalytic activity was characterized by XRD, 29 Si MAS NMR, FT IR, N 2 adsorption desorption isotherms and ICP. The results suggested that the synthesized molecular sieve is mesoporous of typical HMS structure with Cu incorporated into the framework of the molecular sieve.