Method for production of methyl methacrylate by oxidative esterification using a heterogeneous catalyst
A method for preparing methyl methacrylate from methacrolein and methanol; said method comprising contacting in a reactor a mixture comprising methacrolein, methanol and oxygen with a heterogeneous catalyst comprising a support and a noble metal, wherein pH at the reactor outlet is from 3 to 6.7.
1. A method for preparing methyl methacrylate from methacrolein and methanol; said method comprising contacting in a reactor a mixture comprising methacrolein, methanol and oxygen with a heterogeneous catalyst comprising a support and gold, wherein pH at the reactor outlet is from 3 to 6.7, wherein the average diameter of particles of the heterogeneous catalyst is at least 300 microns and at least 90 wt % of the gold is in the outer 70% of catalyst volume.
2. The method of claim 1 in which at least 90 wt % of the gold is in the outer 60% of catalyst volume.
3. The method of claim 2 in which average diameter of particles of the heterogeneous catalyst is at least 400 microns.
4. The method of claim 3 in which the amount of gold as a percentage of the gold and the support is from 0.2 to 5 wt %.
5. The method of claim 4 in which temperature in the reactor is from 40 to 120° C.
6. The method of claim 5 in which at least 95 wt % of the gold is in the outer 50% of catalyst volume.
7. The method of claim 6 in which pH in the reactor is from 4.5 to 6.5.
8. The method of claim 1 in which the support is titania.
9. The method of claim 8 in which at least 90 wt % of the gold is in the outer 60% of catalyst volume.
10. The method of claim 9 in which average diameter of particles of the heterogeneous catalyst is at least 400 microns.