# US 5,705,675 A · Processes for the preparation of 3-(methylthio)propanal and 2-hydroxy-4-(methylthio)butanenitrile > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,705,675 A - Document ID: US5705675A - Status: Granted - Kind: A - Application number: 08/581,249 - Filed: 1995-12-29 - Granted: 1998-01-06 - Earliest claimed: 1995-06-07 - Assignees: Novus International, Inc. - Inventors: Thomas F. Blackburn; Paul F. Pellegrin - Web page: https://patentgrep.com/patent/US5705675A ## CPC - C07C 319/20: by reactions not involving the formation of sulfide groups - C07C 319/18: by addition of thiols to unsaturated compounds - C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS ## Abstract Described herein is a catalytic processes for the preparation of 3-(methylthio)propanal and 2-hydroxy-4-(methylthio)butanenitrile using novel addition catalysts are disclosed. The novel addition catalysts include: triisopropanolamine, nicotinamide, imidazole, benzimidazole, 2-fluoropyridine, poly-4-vinylpyridine, 4-dimethylaminopyridine, picoline, pyrazine, trialkylamines having from three to eighteen carbon atoms in each of the alkyl substituents bonded to the nitrogen atom and tertiary amines having the formula ##STR1## wherein A is aryl, R.sub.1 and R.sub.2 are alkyl and x, a, b and c are integers such that 0.ltoreq.x.ltoreq.3, 1.ltoreq.a.ltoreq.3, 0.ltoreq.b.ltoreq.2, 0.ltoreq.c.ltoreq.2 provided that a+b+c=3. ## Claims ### Claim 1 A process for the manufacture of 3-(methylthio)propanal comprising reacting methyl mercaptan with acrolein in a reaction zone in the presence of an olefin/mercaptan addition reaction catalyst, said catalyst comprising at least one organic base selected from the group consisting of triisopropanolamine, tripropylamine, imidazole, benzimidazole, 2-fluoropyridine, 4-dimethylaminopyridine, picoline, pyrazine, N-methyldiphenethylamine, N-ethyl-3,3'-diphenyldipropylamine and trialkylamines having from five to twelve carbon atoms in each of the alkyl substituents bonded to the nitrogen atom. ### Claim 2 (depends on 1) A process as set forth in claim 1 wherein said olefin/mercaptan addition reaction catalyst comprises at least one organic base selected from the group consisting of triisopropanolamine, picoline, N-methyldiphenethylamine, N-ethyl-3,3'-diphenyldipropylamine and trialkylamines having from five to twelve carbon atoms in each of the alkyl substituents bonded to the nitrogen atom. ### Claim 3 (depends on 2) A process as set forth in claim 2 wherein the molar ratio of organic base to methyl mercaptan introduced into said reaction zone is from about 0.001 to about 0.02. ### Claim 4 (depends on 3) A process as set forth in claim 3 wherein said olefin/mercaptan addition reaction catalyst is combined with an organic acid in said reaction zone. ### Claim 5 (depends on 4) A process as set forth in claim 4 wherein said organic acid is acetic acid and the molar ratio of said organic base to acetic acid introduced into said reaction zone is from about 0.5 to about 2.0. ### Claim 6 (depends on 5) A process as set forth in claim 5 wherein said reaction zone contains a liquid reaction medium comprising 3-(methylthio)propanal and said catalyst, said liquid reaction medium containing between about 0.2% and about 0.75% by weight of said catalyst/organic acid combination. ### Claim 7 (depends on 3) A process as set forth in claim 3 wherein said olefin/mercaptan addition reaction catalyst is combined with a mineral acid in said reaction zone. ### Claim 8 (depends on 7) A process as set forth in claim 7 wherein said mineral acid is selected from the group consisting of sulfuric acid and phosphoric acid and the molar ratio of said olefin/mercaptan addition reaction catalyst to said mineral acid introduced into said reaction zone is from about 1 to about 50. ### Claim 9 (depends on 8) A process as set forth in claim 8 wherein said reaction zone contains a liquid reaction medium comprising 3-(methylthio)propanal and said catalyst, said liquid reaction medium containing between about 0.2% and about 0.75% by weight of said catalyst/mineral acid combination. ### Claim 10 (depends on 2) A process as set forth in claim 2 wherein said olefin/mercaptan addition reaction catalyst comprises N-methyldiphenethylamine. ### Claim 11 (depends on 10) A process as set forth in claim 10 wherein said olefin/mercaptan addition reaction catalyst is combined with an organic acid in said reaction zone. ### Claim 12 (depends on 2) A process as set forth in claim 2 wherein said olefin/mercaptan addition reaction catalyst comprises N-ethyl-3,3'-diphenyldipropylamine. ### Claim 13 (depends on 12) A process as set forth in claim 12 wherein said olefin/mercaptan addition reaction catalyst is combined with an organic acid in said reaction zone. ### Claim 14 A process for the manufacture of 2-hydroxy-4-(methylthio)butanenitrile comprising: reacting methyl mercaptan with acrolein in a reaction zone in the presence of an olefin/mercaptan addition reaction catalyst comprising at least one organic base selected from the group consisting of triisopropanolamine, tripropylamine, imidazole, benzimidazole, 2-fluoropyridine, 4-dimethylaminopyridine, picoline, pyrazine, N-methyldiphenethylamine, N-ethyl-3,3'-diphenyldipropylamine and trialkylamines having from five to twelve carbon atoms in each of the alkyl substituents bonded to the nitrogen atom, thereby producing an intermediate reaction product mixture comprising 3-(methylthio)propanal and said catalyst; and without prior separation of said catalyst from the 3-(methylthio)propanal of said intermediate reaction product mixture, reacting said 3-(methylthio)propanal with hydrogen cyanide to produce 2-hydroxy-4-(methylthio)butanenitrile. ### Claim 15 (depends on 14) A process as set forth in claim 14 wherein said olefin/mercaptan addition reaction catalyst comprises at least one organic base selected from the group consisting of triisopropanolamine, picoline, N-methyldiphenethylamine, N-ethyl-3,3'-diphenyldipropylamine and trialkylamines having from five to twelve carbon atoms in each of the alkyl substituents bonded to the nitrogen atom. ### Claim 16 (depends on 14) A process as set forth in claim 14 wherein said olefin/mercaptan addition reaction catalyst is combined with acetic acid in said reaction zone. ### Claim 17 (depends on 14) A process as set forth in claim 14 wherein an additional amount of an organic base is introduced into said intermediate reaction product mixture to promote the reaction of 3-(methylthio)propanal with hydrogen cyanide. ### Claim 18 (depends on 17) A process as set forth in claim 17 wherein the organic base introduced into the intermediate reaction product mixture comprises at least one organic base selected from the group consisting of triisopropanolamine, picoline, N-methyldiphenethylamine, N-ethyl-3,3'-diphenyldipropylamine and trialkylamines having from five to twelve carbon atoms in each of the alkyl substituents bonded to the nitrogen atom. ### Claim 19 (depends on 17) A process as set forth in claim 17 wherein the organic base introduced into the intermediate reaction product mixture is the same organic base which comprises said olefin/mercaptan addition reaction catalyst used in reacting said methyl mercaptan with said acrolein. ### Claim 20 (depends on 17) A process as set forth in claim 17 wherein the organic base introduced into the intermediate reaction product mixture is pyridine. ### Claim 21 (depends on 17) A process as set forth in claim 17 wherein prior to the introduction of said additional amount of an organic base, said intermediate reaction product mixture contains between about 0.01% and about 1% by weight of said organic base, and after said additional amount of an organic base is introduced into said intermediate reaction product mixture, said intermediate reaction product mixture contains between about 0.05% and about 1% by weight of said organic base. ### Claim 22 (depends on 15) A process as set forth in claim 15 wherein said olefin/mercaptan addition reaction catalyst comprises N-methyldiphenethylamine. ### Claim 23 (depends on 22) A process as set forth in claim 22 wherein said olefin/mercaptan addition reaction catalyst is combined with an organic acid in said reaction zone. ### Claim 24 (depends on 15) A process as set forth in claim 15 wherein said olefin/mercaptan addition reaction catalyst comprises N-ethyl-3,3'-diphenyldipropylamine. ### Claim 25 (depends on 24) A process as set forth in claim 24 wherein said olefin/mercaptan addition reaction catalyst is combined with an organic acid in said reaction zone.