摘要
以杂多酸H3PW12O40(PW12)与正硅酸乙酯(TEOS)混合溶胶,采用胶晶模板法结合煅烧去除模板工艺,成功地制备了PW12/SiO2物质的量比在1/10～1/40之间的三维有序大孔(3DOM)PW12-SiO2催化剂.经SEM,N2吸附,XRD和FTIR等研究表明,PW12含量较低的样品,大孔结构三维规整性十分好.在410℃氧化分解胶晶的条件下,PW12基本保持一级Keggin结构.PW12在样品中以分子簇或微晶存在,其大小随含量增加而增大.PW12高含量时,其含氧键的FTIR振动与纯PW12的基本一致,但低含量时含氧键振动有一定偏移,显示PW12/SiO2相互作用较显著.样品酸性随杂多酸含量增加而增加,但PW12/SiO2物质的量比超过1/30时酸性便减小,呈火山型曲线变化规律.对1-十二烯烷基化反应的催化活性随PW12/SiO2物质的量比的变化与酸性变化有相同的规律.但所有样品的催化反应活性均远高于纯PW12,并且有良好的重复使用性能,使用4次后仍保持新鲜催化剂活性的78%.
By templation via in-situ sol-gel transformation, with calcination （410 ℃） to remove the colloidal crystals, three-dimensionally ordered macroporous （3DOM） H3PW12O40 （PW12）-SiO2 functionalized materials with different PW12/SiO2 molar ratios in a range of 1/10- 1/40 were prepared. The nature of the functionalized materials has been characterized by SEM, N2 adsorption, XRD and FTIR techniques. The results revealed that the macropores were arrayed highly periodically and connected with one another by small windows. The walls of the macropores were of microporous configuration. H3PW12O40 was chemically combined with the support and still maintained its primary Keggin structure. The acidity of the materials showed a change with a volcano curve as PW12 loading increased. High catalytic activity could be found with the samples for the alkylation of benzene with 1-dodecene, and their catalytic activity also demonstrated a similar change to the acidity. A significant recyclability could also be observed with the catalyst： having been reused for 4 times, it retained 78% reactivity compared with the fresh one.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2007年第19期2103-2108,共6页
Acta Chimica Sinica
基金
广东省科技厅十五重点专项(No.A3010302)资助项目.
