In order to overcome the shortcomings of particulate catalyst for oxidative esterification of methacrolein in slurry reactor

the monolithic catalyst(PdxPby/Al2O3-MgO/nickel alloy foam)for direct oxidative esterification of methacrolein (MAL) with methanol to methyl methacrylate (MMA) was prepared using dipping methods. The porous Al2O3-MgO with high surface area on nickel alloy foam support was synthesized using electro-deposition method. The effects of preparation parameters on Al2O3 coating were studied

and the optimum coating was achieved when the volume content of aluminum sol was 35%—40%

the Al2O3 content was 25—30 g·L-1

the stirring speed was 200—250 r·min-1

the deposition voltage was 10—12 V

and the deposition time was 8—12 min. Furthermore

the coating and catalyst were characterized using BET

XRD

SEM

ICP as well as TEM and the catalytic performance of Pd5Pb5/Al2O3-MgO/nickel alloy foam was investigated in a fixed bed reactor. The optimal reaction conditions were determined as:T=80℃

p=0.3 MPa

methanol:MAL molar ratio=8:1

liquid materials flux rate =0.5 ml·min-1

oxygen flux rate=35 ml·min-1 and reaction time=2 h. Under these conditions

MAL conversion and MMA selectivity reached 76.1% and 81.2%

respectively. The results can provide scientific basis for the optimization of methacrolein to methyl methacrylate production process.