摘要
以正硅酸乙酯(TEOS)、钛酸丁酯(TBOT)、四丙基氢氧化铵(TPAOH)分别作硅源、钛源及模板剂,用干胶转化法合成TS-1分子筛.考察了TEOS水解时的水硅比、水解温度、除醇条件、晶化时间及磷酸处理对TS-1分子筛性能的影响.采用XRD、SEM、IR、ICP及N2吸附等手段对样品进行表征,同时以环己酮氨肟化反应考察样品的催化活性.结果表明,使用少量的TPAOH(n(TPAOH)/n(SiO2)=0.15)即可得到性能较好的TS-1,而用磷酸对所得TS-1分子筛处理则能进一步改善TS-1分子筛的性能.当n(SiO2):n(TPAOH):n(H2O)=1:0.15:16时在20℃下水解TEOS,钛硅溶液能自行胶凝,将所得凝胶在75℃下除醇至失重率达65%左右,晶化6d得到TS-1分子筛,产品经磷酸改性后,环己酮转化率达到99.5%,环己酮肟选择性达到98.7%,催化活性与高TPAOH用量合成的TS-1接近,而TPAOH的用量大大降低.
TS-1 was synthesized via dry gel conversion （DGC） method with tetraethyl orthosilieate （TEOS）, tetrabutyl orthotitanate （TBOT） and tetrapropylammonium hydroxide （TPAOH） as silica source, titanium source and template, respectively. The influence of the H2O/SiO2 molar ratio, the hydrolysis temperature, alcohol-removing conditions, the crystallization time and post treatment with phosphate acid were examined. The products were characterized by XRD, SEM, ICP, N2 adsorption and ammoximation of eyelohexanone reaction. The results indicated that TS-1 exhibiting good properties could be synthesized at low TPAOH/SiO2 molar ratio of 0.15 and its properties could be improved by post treatment with phosphate acid. When TEOS was hydrolyzed at 20℃ and the molar ratio of n （ SiO2 ） ： n （ H2O） ： n （TPAOH） was 1： 16： 0.15, the solution could become a gel by itself. After drying the gel at 75 ℃ to a weight loss of about 65%, TS-1 could be successfully synthesized by DGC at 180℃ for 6 d. The post treatment of the TS-1 with phosphate acid could enhance the conversion of eyelohexanone and selectivity of cyclohexanone oxime from 96.2% and 96.6% to 99.5% and 98.7%, respectively.
出处
《分子催化》
EI
CAS
CSCD
北大核心
2008年第1期48-53,共6页
Journal of Molecular Catalysis(China)
基金
国家自然科学基金(20201007)项目
关键词
TS-1
干胶转化
改性
TS-1 molecular sieve
Dry gel conversion method
Modification
