摘要
以白炭黑为硅源,氢氧化四乙基铵为模板剂,氟化钠为矿化剂,采用水热法合成了全硅β沸石（Si/Al〉1 200）,探讨了起始反应混合物组成对全硅β沸石晶化的影响,利用XRD、IR、TG/DTA和SEM等测试技术对产品的结构特性进行了表征。结果表明,按下列化学组成配制初始反应混合物：n（SiO2）∶n（（TEA）2O）∶n（H2O）∶n（NaF）=60∶（17-18）∶（480-660）∶（5-40）,将所得胶状物质转入聚四氟乙烯衬里的20 mL不锈钢反应釜中,在140℃晶化12 d,可合成出全硅β沸石。在以H2O2作氧化剂的苯酚羟基化反应中,所合成的全硅β沸石表现出较高的催化活性,当反应温度为80℃,反应时间为6 h,m（Catalyst）∶m（Phenol）=1∶20,m（Phenol）/m（H2O）=0.6和n（Phenol）/n（H2O2）=2时,苯酚的转化率为34.6%,H2O2的有效利用率达61.2%,邻苯二酚的选择性为69.8%,对苯二酚的选择性为27.0%。
All-Si-β zeolites（ Si/A1 〉 1 200） were synthesized under hydrothermal conditions with fumed silica （SiO2 ） as the silica source, tetraethyl ammonium hydroxide （TEAOH） as the template and sodium fluoride （NaF） as the mineral agent. The effects of the chemical composition of the starting materials on the crystallization of All-Si-β zeolites were investigated. The structural characteristics of the products were determined by means of XRD, IR, TG/DTA and SEM. The results indicate that all-Si-β zeolites can be synthesized from the mixture at a ratio of n （ SiO2 ）： n （ （ TEA）2 O）： n （ H2 O）： n （NaF） = 60： （ 17 - 18 ）： （480 - 660 ）： （ 5 - 40 ） ; the gels obtained were then transferred to a 20 mL tetrafluoroethylene-lined stainless-steel autoclave and kept in oven at 140 ℃ for 12 d. All-Si-β zeolites were used as catalysts in the hydroxylation of phenol with H202 as the oxidant. The results show that all-Si-β zeolites have high catalytic activity. When reaction temperature was 80 ℃, reaction time 6 h, m （Catalyst） ： m （Phenol） = 1 ： 20, m （ Phenol ）/m （ H2 O） = O. 6 and n （ Phenol ） / n（H202） =2, the final conversion of phenol was 34. 6% , the effective conversion of H202 was 61.2% , the yield selectivities for CAT and HQ were 69. 8% and 27.0% respectively. Keywords All-Si-Beta zeolite,catalysis,phenol,hydroxylation
出处
《应用化学》
CAS
CSCD
北大核心
2007年第7期790-795,共6页
Chinese Journal of Applied Chemistry
基金
湖南省自然科学基金(04JJ40011)资助项目
关键词
全硅β沸石
催化
苯酚
羟基化
All-Si-Beta zeolite, catalysis, phenol, hydroxylation
