当前位置: X-MOL 学术React. Kinet. Mech. Catal. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Improved catalytic performance of mesoporous ZSM-5 nanocrystalline zeolite prepared by the cationic surfactant-ammonium salt mixed agent method in the methanol to gasoline reaction
Reaction Kinetics, Mechanisms and Catalysis ( IF 1.7 ) Pub Date : 2019-10-31 , DOI: 10.1007/s11144-019-01685-8
Mina Sadrara , Mohammadreza Khanmohammadi Khorrami , Amir Bagheri Garmarudi

A mixed organic agent system was employed to achieve mesoporous highly crystalline ZSM-5 zeolite. Decyltrimethylammonium bromide (DeTAB) and tetramethyl ammonium hydroxide (TMAOH) were used as the mesogenous and molecular templates respectively in the synthesis gel with a composition of 60SiO2: 1Al2O3:12Na2O:3150H2O:xDeTAB:8TMAOH. The sole presence of DeTAB as the mesogenous template in the synthesis gel led to the high degrees of mesoporosity in the ZSM-5/xD samples but negatively affected the intrinsic properties of zeolites. At the high concentration of DeTAB (x = 0.7), the mesopore volume dramatically increased while the relative crystallinity and the total acid sites critically decreased. By adding the TMA+ ions as a microporous template to the ZSM-5/0.7D synthesis gel, not only a zeolite with well-developed mesoporosity was obtained but also its crystal structure and the intrinsic acidity were preserved. The catalyst samples were characterized by FESEM, TEM, XRD, FT-IR, nitrogen adsorption–desorption isotherms, NH3-TPD and TGA techniques. The ZSM-5/0.7D/T exhibited higher surface area, higher mesopore volume, higher crystallinity and more acid sites than the ZSM-5/0.7D. The catalytic conversion of methanol to gasoline was conducted in a fixed bed reactor at T = 390 °C and WHSV = 4.74 h−1. In ZSM-5/0.7D/T catalyst the mesoporosity formation without severely damaging the crystal structure and the acidity of the zeolite led to the best catalytic performance including the highest liquid hydrocarbon yield, most stable catalytic performance and longest catalytic lifetime.

中文翻译:

阳离子表面活性剂-铵盐混合剂法制得的介孔ZSM-5纳米晶沸石在甲醇制汽油中的催化性能提高

使用混合的有机试剂体系来获得中孔高度结晶的ZSM-5沸石。组成为60SiO 2:1Al 2 O 3:12Na 2 O:3150H 2的合成凝胶中,分别使用癸基三甲基溴化铵(DeTAB)和四甲基氢氧化铵(TMAOH)作为介孔模板和分子模板。O:xDeTAB:8TMAOH。合成凝胶中唯一以DeTAB作为介孔模板的物质导致ZSM-5 / xD样品具有高度的介孔性,但对沸石的固有性质产生负面影响。在高浓度的DeTAB(x = 0.7)时,中孔体积急剧增加,而相对结晶度和总酸位则急剧下降。通过将TMA +离子作为微孔模板添加到ZSM-5 / 0.7D合成凝胶中,不仅获得了具有良好中孔性的沸石,而且还保留了其晶体结构和固有酸度。通过FESEM,TEM,XRD,FT-IR,氮吸附-解吸等温线,NH 3对催化剂样品进行了表征。-TPD和TGA技术。与ZSM-5 / 0.7D相比,ZSM-5 / 0.7D / T具有更高的表面积,更高的中孔体积,更高的结晶度和更多的酸位。在T = 390°C和WHSV = 4.74 h -1的固定床反应器中进行甲醇到汽油的催化转化。在ZSM-5 / 0.7D / T催化剂中,介孔形成而不会严重破坏晶体结构和沸石的酸性,导致了最佳的催化性能,包括最高的液态烃收率,最稳定的催化性能和最长的催化寿命。
更新日期:2019-12-11
down
wechat
bug