CAJ | 학술논문

以有机硅烷化的二氧化硅为硅源,制备了由纳米粒子聚集而成的、具有晶间和晶内介孔的微球状ZSM-5(MMZ-5)沸石.通过吡啶(Py)和2,6-二叔丁基吡啶(DTBPy)在介孔沸石表面吸附的原位红外测试,对其酸性进行了表征.与微孔ZSM-5沸石相比, MMZ-5沸石上的Lewis酸位和总酸位增加,特别是探针大分子DTBPy(动力学直径约为1.05 nm)可及的Br?nsted酸位显著提高.萘在MMZ-5沸石上的苄基化催化结果表明,反应发生在拥有大量活性位的沸石外表面,大的沸石外表面为该催化反应提供了作用空间,从而提高了沸石活性位的有效利用率,使MMZ-5沸石上萘的苄基化反应活性显著提高,能够生成大分子产物一苄基萘和二苄基萘；其中,一苄基萘的选择性约为79%,且随着反应时间的延长, MMZ-5沸石大的晶内介孔(3-5 nm)为反应提供了有效反应空间,促进一苄基萘向二苄基萘转化.异构体α-一苄基萘和β-一苄基萘的摩尔比值约为83：17,该值不随着温度和转化率的变化而改变.
이유궤규완화적이양화규위규원,제비료유납미입자취집이성적、구유정간화정내개공적미구상ZSM-5(MMZ-5)비석.통과필정(Py)화2,6-이숙정기필정(DTBPy)재개공비석표면흡부적원위홍외측시,대기산성진행료표정.여미공ZSM-5비석상비, MMZ-5비석상적Lewis산위화총산위증가,특별시탐침대분자DTBPy(동역학직경약위1.05 nm)가급적Br?nsted산위현저제고.내재MMZ-5비석상적변기화최화결과표명,반응발생재옹유대량활성위적비석외표면,대적비석외표면위해최화반응제공료작용공간,종이제고료비석활성위적유효이용솔,사MMZ-5비석상내적변기화반응활성현저제고,능구생성대분자산물일변기내화이변기내；기중,일변기내적선택성약위79%,차수착반응시간적연장, MMZ-5비석대적정내개공(3-5 nm)위반응제공료유효반응공간,촉진일변기내향이변기내전화.이구체α-일변기내화β-일변기내적마이비치약위83：17,해치불수착온도화전화솔적변화이개변.
A microspherical ZSM-5 zeolite aggregated from nanosized zeolite crystals with intra-and inter-crystal ine mesoporous structures (MMZ-5) was prepared using presilanized silica as silica source. The acidic properties of this mesoporous zeolite were characterized via Fourier transform infrared spectroscopy (FTIR) in combination with pyridine (Py) and 2,6-di-tert-butylpyridine (DTBPy). Compared with conventional microporous ZSM-5, the MMZ-5 zeolite possessed more Lewis acid sites and many more accessible Br?nsted acid sites for bulky DTBPy molecule (1.05 nm in diameter). This mesoporous zeolite thus afforded both effective active sites and reaction voids al owing the reaction of larger molecules, resulting in enhanced catalytic activity and stability of the MMZ-5 zeolite during the benzylation of naphthalene with benzyl chloride (BC) to form bulky monobenzylnaphthalenes and dibenzylnaphthalenes, during which the selectivity for monobenzylnaphthalenes was estimated to be about 79%. Moreover, the selectivity for dibenzylnaphthalenes was enhanced with increasing reaction time, owing to the consecutive reactions between monobenzylnaphthalenes and BC occurring at the effective reaction voids of the MMZ-5 zeolite. The distribution of the monobenzylnaphthalene isomers (α-BN andβ-BN) was found to be independent of both reaction temperature and extent of BC conversion, theα-BN/β-BN molar ratio being about 83:17.