# US 10,865,179 B2 · Method for production of methyl methacrylate by oxidative esterification using a heterogeneous catalyst

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- Number: US 10,865,179 B2
- Document ID: US10865179B2
- Status: Granted
- Kind: B2
- Application number: 16/648,286
- Filed: 2018-09-12
- Published: 2020-07-09
- Granted: 2020-12-15
- Earliest claimed: 2017-09-19
- Assignees: Dow Global Technologies LLC; Rohm and Haas Company
- Applicants: Dow Global Technologies LLC; Rohm and Haas Company
- Inventors: Jeffrey Herron; Daniel J. Arriola; D. Wayne Blaylock; Wen-Sheng Lee; Victor Sussman; Daniel A. Hickman; Kirk W. Limbach
- Web page: https://patentgrep.com/patent/US10865179B2

## CPC

- C07C 67/39: by oxidation of groups which are precursors for the acid moiety of the ester
- C07C 67/40: by oxidation of primary alcohols
- B01J 23/38: of noble metals
- B01J 23/44: Palladium
- B01J 23/52: Gold
- B01J 23/58: with alkali- or alkaline earth metals
- B01J 23/63: with rare earths or actinides
- B01J 23/64: with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
- B01J 23/66: Silver or gold
- B01J 35/397: {Egg shell like}
- B01J 35/40: characterised by dimensions, e.g. grain size (in a colloidal state B01J35/23; crystallite size B01J35/77)
- C07C 69/54: Acrylic acid esters; Methacrylic acid esters
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS

## Abstract

A method for preparing methyl methacrylate from methacrolein and methanol. The method comprises contacting a mixture comprising methacrolein, methanol and oxygen with a heterogeneous catalyst comprising a support and a noble metal, wherein oxygen concentration at a reactor outlet is from 1 to 7.5 mol % and wherein pH at a reactor outlet is no greater than 7.5.

## Claims

### Claim 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 a noble metal, wherein the noble metal comprises gold, wherein the catalyst has an average diameter of at least 300 microns, wherein oxygen concentration at a reactor outlet is from 1 to 7.5 mol % and wherein pH at a reactor outlet is no greater than 7.5.

### Claim 2 (depends on 1)

The method of claim 1 in which the reactor is an axial flow reactor having a liquid-phase superficial velocity of 0.5 to 20 mm/s and an average partial pressure of oxygen greater than 50 kPa.

### Claim 3 (depends on 2)

The method of claim 2 in which the catalyst has an average diameter from 400 microns to 10 mm.

### Claim 4 (depends on 3)

The method of claim 3 in which the catalyst is contained in a catalyst bed which is at a temperature from 40 to 120° C.

### Claim 5 (depends on 4)

The method of claim 4 in which pH in the reactor is from 3 to 7.2.

### Claim 6 (depends on 5)

The method of claim 5 in which oxygen concentration at a reactor outlet is from 1.6 to 6 mol %.

### Claim 7 (depends on 1)

The method of claim 1 in which the support is selected from the group consisting of γ-, δ-, or θ-alumina, silica, magnesia, titania, zirconia, hafnia, vanadia, niobium oxide, tantalum oxide, ceria, yttria, lanthanum oxide and combinations thereof.

### Claim 8 (depends on 7)

The method of claim 7 in which methanol and methacrolein are fed to a reactor containing the catalyst bed in a molar ratio from 1:1 to 10:1, respectively.

### Claim 9 (depends on 8)

The method of claim 8 in which at least 90 wt % of the noble metal is in the outer 70% of catalyst volume.