两种钛硅分子筛合成体系的比较

分别在四丙基溴化铵(TPABr)-正丁胺体系和以四丙基氢氧化铵(TPAOH)为模板剂的修正经典合成法体系中合成了钛硅分子筛TS-1，对比了两个体系的晶化过程，并对所获得的TS-1进行了XRD、IR、SEM表征和催化反应性能评价。结果表明，在TPABr-正丁胺体系中合成TS-1，晶化速率较慢，母液pH值先降后升；而以TPAOH为模板剂合成的TS-1，晶化速率很快，母液pH值先升后降。对比两种分子筛的XRD、IR表征结果，未发现明显的差别；但SEM观察结果表明，TPABr-正丁胺体系合成的TS-1晶粒较大。在丙烯环氧化反应中，两种分子筛均具有较好的催化性能；在苯酚羟基化和苯乙烯氧化反应中，以TPAOH为模板剂合成的分子筛具有较高的活性。采用TPABr-正丁胺体系合成时，由于体系的碱度较低，液相中硅酸盐的浓度较低，因而所得TS-1比修正经典合成法体系所得的晶粒为大。这种廉价的较大晶粒的TS-1可以满足扩散限制较小的丙烯环氧化反应的要求。

COMPARISON OF TWO SYNTHETIC SYSTEMS OF TITANIUM SILICALITE

TS 1 samples were synthesized in presence of TPABr and n butylamine or by the modified classical synthesis with TPAOH as template.The crystallization course of two syntheses was compared.TS 1 samples obtained were characterized by XRD,IR and SEM and were used as the catalyst in propylene epoxidation,phenol hydroxylation and styrene oxidation.The crystallization rate in the former synthesis is much slower than that in the later.The pH value of the mother liquid in presence of TPABr and n butylamine decreased at the beginning and then increased after a period of time.But the pH value of the mother liquid in the modified classical synthesis exhibited the reverse trend.The samples obtained from the two systems presented similar XRD or IR spectra,but the crystal size of TS 1 observed from SEM was much smaller in the modified classical synthesis.Both TS 1 samples exhibited good performance in propylene epoxidation,but the TS 1 sample obtained from the modified classical synthesis presented the higher activity in phenol hydroxylation.The low alkalinity in the synthesis using TPABr and n butylamine resulted in lower nucleation rate and larger crystal size of TS 1,but this kind of TS 1 still exhibited high activity in the reactions with less diffusion limitation such as propylene epoxidation.