# US 10,766,847 B2 · Method for producing methylmethacrylate > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,766,847 B2 - Document ID: US10766847B2 - Status: Granted - Kind: B2 - Application number: 16/161,395 - Filed: 2018-10-16 - Published: 2019-04-18 - Granted: 2020-09-08 - Earliest claimed: 2013-04-19 - Assignees: Rohm Co., Ltd. - Applicants: RöHm GmbH - Inventors: Steffen Krill; Torsten Balduf; Martin Koestner; Matthias Groemping; Alexander Lygin; Rudolf Burghardt - Web page: https://patentgrep.com/patent/US10766847B2 ## CPC - C07C 67/39: by oxidation of groups which are precursors for the acid moiety of the ester - C07C 45/75: Reactions with formaldehyde - C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS ## Abstract The present invention relates to a process for producing methyl methacrylate, comprising the following steps: A) producing methacrolein and B) reacting the methacrolein obtained in step A) in an oxidative esterification reaction to give methyl methacrylate, characterized in that the two steps A) and B) take place in a liquid phase at a pressure of from 2 to 100 bar, and step B) is carried out in the presence of a heterogeneous noble-metal-containing catalyst comprising metals and/or comprising metal oxides. ## Claims ### Claim 1 A process for producing methyl methacrylate, the process comprising: A) producing methacrolein from propanal and formaldehyde and B) reacting the methacrolein in an oxidative esterification reaction to obtain methyl methacrylate, wherein the producing A) and the reacting B) take place in a liquid phase at a pressure of from 2 to 100 bar, and the reacting B) is carried out in the presence of a heterogeneous noble-metal-comprising catalyst comprising a metal and/or a metal oxide, and the reaction mixture of the producing A) is passed into a column for steam stripping, and a top phase of the steam stripper, which comprises the methacrolein and water, is then separated with a phase separator into an upper phase and a lower phase, whereby the upper phase comprises the methacrolein. ### Claim 2 (depends on 1) The process according to claim 1, wherein the producing A) is carried out in the presence of from 0.1 to 20 mol % of organic base and from 0.1 to 20 mol % of acid, based in each case on propanal. ### Claim 3 (depends on 1) The process according to claim 1, wherein the producing A) is carried out at a temperature of from 100 to 300° C. ### Claim 4 (depends on 1) The process according to claim 1, wherein the producing A) is carried out at a pressure of from 5 to 100 bar. ### Claim 5 (depends on 1) The process according to claim 1, wherein the heterogeneous oxidation catalyst comprises one or more ultra-finely dispersed metals with an average particle size of <20 nm selected from the group consisting of gold, palladium, ruthenium, rhodium, and silver. ### Claim 6 (depends on 1) The process according to claim 1, wherein the heterogeneous oxidation catalyst comprises at least one member which is in a metallic form and/or an oxidized form and which comprises a metal selected from the group consisting of lithium, sodium, potassium, calcium, magnesium, scandium, yttrium, a lanthanoid with an atomic number of from 57 to 71, silicon, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, cadmium, boron, aluminium, gallium, indium, thallium, germanium, tin, lead, antimony, bismuth, and tellurium. ### Claim 7 (depends on 2) The process according to claim 2, wherein the organic base comprises a secondary amine. ### Claim 8 (depends on 2) The process according to claim 2, wherein the acid comprises at least one organic acid. ### Claim 9 (depends on 2) The process according to claim 2, wherein a molar ratio of the acid to the organic base ranges from 20:1 to 1:20. ### Claim 10 (depends on 1) The process according to claim 1, wherein the producing A) is carried out with a residence time ranging from 0.1 to 300 seconds. ### Claim 11 (depends on 1) The process according to claim 1, wherein the reacting B) is carried out with a pressure ranging from 2 to 50 bar. ### Claim 12 (depends on 1) The process according to claim 1, wherein the oxidative esterification reaction is carried out at a temperature ranging from 10 to 200° C. ### Claim 13 (depends on 1) The process according to claim 1, wherein the oxidative esterification reaction takes place in the presence of methanol with a molar ratio of methanol to methacrolein ranging from 1:1 to 50:1. ### Claim 14 (depends on 1) The process according to claim 1, wherein the producing A) and the reacting B) are carried out in a continuous process. ### Claim 15 (depends on 1) The process according to claim 1, wherein a volume ratio of a reactor in the producing A) to a reactor in the reacting B) ranges from 1:1000 to 1:100. ### Claim 16 (depends on 1) The process according to claim 1, wherein a total amount of any separately added water in the producing A) and the reacting B) during the process is not greater than 100 mol %, based on methacrolein. ### Claim 17 (depends on 1) The process according to claim 1, wherein no water is separately added in the producing A) and the reacting B) during the process. ### Claim 18 (depends on 1) The process according to claim 1, wherein a content of water in reaction mixture during the reacting B) is at most 10% by weight based on a total weight of the reaction mixture. ### Claim 19 (depends on 18) The process according to claim 18, wherein no dewatering is conducted after the producing A) and before the reacting B).