Preparation of CaO/HMCM-22 zeolite catalyst with acid-base bifunction with ultrasonic assistance

doi:10.3969/j.issn.0438-1157.2014.10.024

Abstract

Abstract: CaO/HMCM-22 zeolite catalysts were prepared by ultrasonic impregnation and characterized by XRD, N₂ physical adsorption-desorption, SEM, FT-IR, NH₃-TPD and CO₂-TPD. The structure of MCM-22 zeolite still remained after CaO modification with ultrasonic assistance. Ultrasonic cavitation could reduce the agglomeration between particles, improve the dispersion of CaO on the surface of zeolite and increase the accessible catalytic active sites. By increasing CaO loading, the strength and content of base increased, while the strength of strong acid decreased significantly and the amount of weak acidic sites increased slightly. Knoevenagel condensation reactions were conducted over the synthesized catalysts. The strategy developed here showed excellent catalytic performance for this reaction compared with the conventional impregnation method and the conversion of benzaldehyde reached 88.3% under optimal ultrasonic irradiation within 2 h reaction. The catalytic performance of CaO/HMCM-22 was better than that of HMCM-22 and CaO/NaMCM-22, resulting in good catalytic activity for Knoevenagel condensation reactions and obvious acid-base synergetic effects. The reusability of the synthesized catalysts with ultrasonic assistance was also investigated. Obvious improvment was achieved and conversion of benzaldehyde was above 65% after being reused 5 times.

Key words: ultrasonic impregnation, CaO, acid-base bifunction, Knoevenagel condensation, catalyst, zeolite

摘要： 采用超声浸渍法制备了一系列CaO改性的HMCM-22分子筛催化剂，使用XRD、N₂物理吸附-脱附、SEM、FT-IR、NH₃-TPD及CO₂-TPD等技术对催化剂物化性质进行了表征。结果发现在超声作用下经CaO改性后MCM-22分子筛的结构没有发生变化；超声空化作用降低了催化剂晶粒之间的团聚，促进了CaO在分子筛表面的分散，增加了可接触的催化活性位；随着CaO负载量的增加，催化剂上碱强度和碱量显著增加，而强酸含量明显减少，弱酸酸位有所增加。对催化剂在Knoevenagel缩合反应中的催化性能研究表明：与传统浸渍法相比，超声浸渍法所制备催化剂的催化活性明显较高，在优化的超声条件下反应2 h苯甲醛转化率即可达88.3%。催化剂CaO/HMCM-22的催化性能优于HMCM-22和CaO/NaMCM-22，对Knoevenagel缩合反应体现出明显的酸碱协同催化作用。超声法制备的催化剂重复使用性能显著提升，经过5次重复使用后苯甲醛转化率仍保持在65%以上。

关键词: 超声浸渍, 氧化钙, 酸碱双功能, Knoevenagel缩合反应, 催化剂, 沸石

CLC Number:

O643.3

WANG Junge, LIANG Jinhua, SUN Shoufei, ZHANG Wenfei, REN Xiaoqian, JIANG Min. Preparation of CaO/HMCM-22 zeolite catalyst with acid-base bifunction with ultrasonic assistance[J]. CIESC Journal, 2014, 65(10): 3924-3930.

王俊格, 梁金花, 孙守飞, 张文飞, 任晓乾, 姜岷. 超声辅助制备酸碱双功能CaO/HMCM-22分子筛催化剂[J]. 化工学报, 2014, 65(10): 3924-3930.

References 26

[1]	Zhang X F, Lai E S M, Martin-Aranda R, Yeung K L. An investigation of Knoevenagel condensation reaction in microreactors using a new zeolite catalyst [J]. Appl. Catal. A, 2004, 261(1):109-118
[2]	Hein R W, Astle M J, Shelton J R. Ion-exchange resin catalysis of the Knoevenagel condensation of ketones [J]. J. Org. Chem., 1961, 26(12): 4874-4878
[3]	Lan D X, Lin D, Zhao H M, Ma L, Chun Y. Preparation of Al2O3-MgO acid/base bifunctional material with high specific surface area using degreasing cotton as exotemplate [J]. Chin. J. Catal., 2011, 32(7): 1214-1219
[4]	Shao Y Q, Guan J Q, Wu S J, Liu H, Liu B, Kan Q B. Synthesis, characterization and catalytic activity of acid-base bifunctional materials by controlling steric hindrance [J]. Micropor. Mesopor. Mater., 2010, 128(1/2/3): 120-125
[5]	Macario A, Giordano G, Onida B, Cocina D, Tagarelli A, Giuffre A M. Biodiesel production process by homogeneous/heterogeneous catalytic system using an acid-base catalyst [J]. Appl. Catal. A, 2010, 378(2): 160-168
[6]	Lei X D, Zhang F Z, Yang L, Guo X X, Tian Y Y, Fu S S, Li F, Evans D G, Duan X. Highly crystalline activated layered double hydroxides as solid acid-base catalysts [J]. AIChE J., 2007, 53(4): 932-940
[7]	Postole G, Chowdhury B, Karmakar B, Pinki K, Banerji J, Auroux A. Knoevenagel condensation reaction over acid-base bifunctional nanocrystalline CexZr1-xO2 solid solutions [J]. J. Catal., 2010, 269(1): 110-121
[8]	Yu Z W, Wang Q, Chen L, Deng F. Brønsted/Lewis acid sites synergy in H-MCM-22 zeolite studied by H-1 and Al-27 DQ-MAS NMR spectroscopy [J]. Chin. J. Catal., 2012, 33(1): 129-139
[9]	Chu N B, Wang J Q, Zhang Y, Yang J H, Lu J M, Yin D H. Nestlike hollow hierarchical MCM-22 microspheres: synthesis and exceptional catalytic properties [J]. Chem. Mater., 2010, 22(9): 2757- 2563
[10]	Laforge S, Martin D, Guisnet M. m-Xylene transformation over H-MCM-22 zeolite(Ⅱ): Method for determining the catalytic role of the three different pore systems [J]. Micropor. Mesopor. Mater., 2004, 67(2/3): 235-244
[11]	Zhang W F, Liang J H, Liu Y Q, Sun S F, Ren X Q, Jiang M. Knoevenagel condensation reaction over acid-base bifunctional MgO/HMCM-22 catalysts [J]. Chin. J. Catal., 2013, 34(3): 559-566
[12]	Zhou T, Chen B D, Yao A H, Wang D P. CdS-graphene nanohybrids: facile ultrasonic synthesis and photocatalytic performance [J]. Chin. J. Inorg. Chem., 2013, 29(2): 231-236
[13]	Lindley J. Sonochemical effects on syntheses involving solid and supported catalysts [J]. Ultrason., 1992, 30(3): 163-167
[14]	Dantsin G, Suslick K S. Sonochemical preparation of a nanostructured bifunctional catalyst [J]. J. Am. Chem. Soc., 2000, 122(21): 5214- 5215
[15]	Bianchi C L, Gotti E, Toscano L, Ragaini V. Preparation of Pd/C catalysts via ultrasound: a study of the metal distribution [J]. Ultrason. Sonochem., 1997, 4(4): 317-320
[16]	Zhou X F, Chen Q L, Tao Y W, Weng H X. Influence of ultrasound impregnation on the performance of Co/Zr/SiO2 catalyst during Fischer-Tropsch synthesis [J]. Chin. J. Catal., 2011, 32(7): 1156-1165
[17]	Liang X Y, Zhang L M, Ding H Y, Qin Y N. Supported catalyst LaCoO3/gamma-A12O3 prepared by impregnating under ultrasound [J]. Acta. Phys-Chim. Sin., 2003, 19(7): 666-669
[18]	Pirola C, Bianchi C L, Di Michele A, Diodati P, Boffito D, Ragaini V. Ultrasound and microwave assisted synthesis of high loading Fe-supported Fischer-Tropsch catalysts [J]. Ultrason. Sonochem., 2010, 17(3): 610-616
[19]	Wu Y J, Ren X Q, Lu Y D, Wang J. Rapid synthesis of zeolite MCM-22 by acid-catalyzed hydrolysis of tetraethylorthosilicate [J]. Mater. Lett., 2008, 62(2):317-319
[20]	Xue B, Li Y X, Deng L J. Selective synthesis of p-xylene by alkylation of toluene with dimethyl carbonate over MgO-modified MCM-22 [J]. Catal. Commun., 2009, 10(12):1609-1614
[21]	Shang Y C, Yang P P, Jia M J, Zhang W X, Wu T H. Modification of MCM-22 zeolites with silylation agents: acid properties and catalytic performance for the skeletal isomerization of n-butene [J]. Catal. Commun., 2008, 9(5): 907-912
[22]	Shu Y Y, Ma D, Xu L Y, Xu Y D, Bao X H. Methane dehydro- aromatization over Mo/MCM-22 catalysts: a highly selective catalyst for the formation of benzene [J]. Catal. Lett., 2000, 70(1/2): 67-73
[23]	Ursachi I, Vasile A, Ianculescu A, Vasile E, Stancu A. Ultrasonic- assisted synthesis and magnetic studies of iron oxide/MCM-41 nanocomposite [J]. Mater. Chem. Phys., 2011, 130(3): 1251-1259
[24]	Corma A, Corell C, Fornés V, Kolodziejski W, Perezpariente J. Infrared-spectroscopy, thermoprogrammed desorption, and nuclear-magnetic-resonance study of the acidity, structure, and stability of zeolite MCM-22 [J]. Zeolite, 1995, 15(7): 576-582
[25]	Kumar G S, Saravanamurugan S, Hartmann M, Palanichamy M, Murugesan V. Synthesis, characterisation and catalytic performance of HMCM-22 of different silica to alumina ratios [J]. J. Mol. Catal. A, 2007, 272(1/2): 38-44
[26]	Sakthivel A, Komura K, Huang S J, Wu P H, Liu S B, Sasaki Y, Sugi Y. Calcium-incorporated mesoporous aluminosilicates: synthesis, characterization, and applications to the condensation of long-chain fatty acid with long-chain amine and alcohol [J]. Ind. Eng. Chem. Res., 2010, 49(1): 65-71