# US 5,705,701 A · Process for producing trimethylsulfoxonium bromide

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 5,705,701 A
- Document ID: US5705701A
- Status: Granted
- Kind: A
- Application number: 08/773,063
- Filed: 1996-12-24
- Granted: 1998-01-06
- Earliest claimed: 1995-12-28
- Assignees: Kureha Kagaku Kogyo Kabushiki Kaisha
- Inventors: Kazuhiko Sunagawa
- Web page: https://patentgrep.com/patent/US5705701A

## CPC

- C07C 381/00: Compounds containing carbon and sulfur and having functional groups not covered by groups C07C301/00 - C07C337/00
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS

## Abstract

In a process for producing trimethylsulfoxonium bromide by reacting dimethyl sulfoxide and methyl bromide, methyl bromide is added to a mixture of dimethyl sulfoxide and a stabilizing agent under atmospheric pressure intermittently or continuously so that the final molar ratio of methyl bromide to dimethyl sulfoxide becomes 0.40:1 to 0.70:1, with the temperature of dimethyl sulfoxide being maintained at a temperature of 50.degree. to 75.degree. C. This process can realize a reduction of reaction time, an improvement of yield and establishment of safety of producing operations.

## Claims

### Claim 1

A process for producing trimethylsulfoxonium bromide which comprises reacting dimethyl sulfoxide with methyl bromide by adding methyl bromide to a mixture of dimethyl sulfoxide and a stabilizing agent under atmospheric pressure intermittently or continuously so that the final molar ratio of methyl bromide to dimethyl sulfoxide will become 0.40:1 to 0.70:1, with the temperature of dimethyl sulfoxide being maintained at a temperature of 50.degree. to 75.degree. C., to react dimethyl sulfoxide and methyl bromide.

### Claim 2 (depends on 1)

The process according to claim 1, wherein after the addition of methyl bromide has been completed, the reaction mixture is stirred at a temperature of 50.degree. to 75.degree. C. for 3 to 18 hours.

### Claim 3 (depends on 1)

The process according to claim 1, wherein the water contents of dimethyl sulfoxide and methyl bromide as starting materials are both not more than 400 ppm.

### Claim 4 (depends on 1)

The process according to claim 1, wherein the amount of methyl bromide used is 0.45 to 0.55 mol based on one mol of dimethyl sulfoxide.

### Claim 5 (depends on 4)

The process according to claim 4, wherein the amount of the stabilizing agent used is 0.002 to 0.05 mol based on one mol of dimethyl sulfoxide.

### Claim 6 (depends on 1)

The process according to claim 1, wherein at least one stabilizing agent selected from the group consisting of trimethyl orthoformate, triethyl orthoformate, tripropyl orthoformate, tetramethyl orthocarbonate, tetraethyl orthocarbonate, tetraisopropyl orthocarbonate and tetrapropyl orthocarbonate is added to dimethyl sulfoxide in an amount of 0.002 to 0.05 mol based on one mol of dimethyl sulfoxide, and then methyl bromide is added to the resultant mixture in such a manner that gentle reflux is maintained in the condenser.

### Claim 7 (depends on 6)

The process according to claim 6, wherein the stabilizing agent is trimethyl orthoformate.

### Claim 8 (depends on 6)

The process according to claim 6, wherein the amount of the stabilizing agent used is 0.004 to 0.02 mol based on one mol of dimethyl sulfoxide.

### Claim 9 (depends on 6)

The process according to claim 6, wherein reflux is carried out using a condenser cooled by passing a coolant of a temperature of -50.degree. to -10.degree. C.