Ca/HMCM-22 and CaHMCM-22 zeolite catalysts were prepared by impregnation and ion exchange respectively.The catalysts were characterized by XRD

TPD

FT-IR

and ICP.When CaSO4 loading was less than 6.5%

CaSO4 could be highly dispersed on HMCM-22 zeolite.A few variations in the strength and content of weak acid

and a slightly decrease of the content of strong acid were found in the two catalysts.However

the strength and content of weak and strong base on CaHMCM-22 were more than those on Ca/HMCM-22 after modification.The two catalysts exhibited good catalytic performance for the synthesis of monododecylphosphate by esterification of phosphoric acid with equimolar lauryl alcohol.The catalytic activity over Ca/HMCM-22 zeolite was higher than the catalytic activities of HMCM-22 and Ca/NaMCM-22 zeolite

CaSO4 in synergy with acid sites and base sites of zeolite catalyst accelerated the esterification.The catalytic activity over CaHMCM-22 exchanged 3 times was also better than those of HMCM-22 and CaNaMCM-22 zeolite.Combined with the results of characterization and esterification

the presence of acidic and basic sites promoted effectively the synthesis of monododecylphosphate.