碱源/氟体系Ti-MWW分子筛的合成

Synthesis of Ti-MWW molecule sieves with fluorine ion and alkali sources

使用不同的碱源(氨水、己二胺和三乙醇胺)替代合成Ti-MWW分子筛所用40%的模板剂哌啶,并添加适量的氟化氢铵作为矿化剂。所得的样品通过XRD、UV-Vis、FT-IR和SEM进行表征分析,并考察不同碱源替代合成Ti-MWW分子筛在过氧化氢为氧化剂丙烯醇环氧化反应中的催化性能。结果表明,使用不同碱源合成的Ti-MWW分子筛均具有良好的MWW拓扑结构。相比于常规方法合成的Ti-MWW分子筛,氨水为碱源时,丙烯醇转化率增加了12个百分点,选择性下降了1个百分点;三乙醇胺作为碱源时,丙烯醇转化率增加了2.9个百分点,缩水甘油选择性上升5.5个百分点。采用三乙醇胺为碱源合成的Ti-MWW分子筛显著提高了缩水甘油选择性。

Titanium silicate Ti - MWW molecule sieves were synthesized by using different alkali sources, ammonia,hexanediamine and triethanolamine, to replace 40% of template piperidine and adding proper amount of ammonium bifluoride as mineralization agent. The as - synthesized samples were characterized by XRD, UV- Vis, FT- IR and SEM, and their catalytic performances were evaluated in epoxidation reaction of allyl alcohol. The results showed that the samples exhibited MWW topology. Compare with Ti - MWW molecule sieves synthesized by traditional method, the conversion on ammonia replaced sample increased by 12 percentage points, but the selectivity decreased by 1 percentage point. The conversion and selectivity on triethanolamine replaced sample improved by 2.9 percentage points and 5.5 percentage points,respectively. Ti - MWW molecule sieve prepared with triethanolamine as alkali source increased the selectivity to epihydric alcohol obviously.