TY - JOUR
T1 - Preparation of CaO/HMCM-22 zeolite catalyst with acid-base bifunction with ultrasonic assistance
AU - Wang, Junge
AU - Liang, Jinhua
AU - Sun, Shoufei
AU - Zhang, Wenfei
AU - Ren, Xiaoqian
AU - Jiang, Min
N1 - Publisher Copyright:
©All Rights Reserved
PY - 2014/10/1
Y1 - 2014/10/1
N2 - 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 improvement was achieved and conversion of benzaldehyde was above 65% after being reused 5 times.
AB - 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 improvement was achieved and conversion of benzaldehyde was above 65% after being reused 5 times.
KW - Acid-base bifunction
KW - CaO
KW - Catalyst
KW - Knoevenagel condensation
KW - Ultrasonic impregnation
KW - Zeolite
UR - http://www.scopus.com/inward/record.url?scp=84908102453&partnerID=8YFLogxK
U2 - 10.3969/j.issn.0438-1157.2014.10.024
DO - 10.3969/j.issn.0438-1157.2014.10.024
M3 - 文章
AN - SCOPUS:84908102453
SN - 0438-1157
VL - 65
SP - 3924
EP - 3930
JO - Huagong Xuebao/CIESC Journal
JF - Huagong Xuebao/CIESC Journal
IS - 10
ER -