The Pd-Pb catalyst supported on Al2O3 was prepared by the two-step impregnation method.The oxidative esterification of methacrolein （MAL） to methyl methacrylate （MMA） was carried out in a stainless bubble autoclave over the catalyst.The influences of the reaction conditions on catalytic activity were investigated in detail.The optimal reaction conditions were as follows: T=80℃, P=0.3 MPa, methanol∶MAL=8∶1 （ molar ratio ）, catalyst mass concentration in the reaction system 3.84%, pH of the reaction system 7—8, oxygen flux rate 30 ml·min -1 .Under the above conditions,MAL conversion and MMA selectivity reached 91% and 84%, respectively.The catalyst was recycled for seven times and still kept good selectivity.
