# US 5,710,347 A · Method of producing a high-melting powder of 2,2-bis›4'-(2",3"-dibromopropoxy)-3',5'-dibromophenyl!-propane

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- Number: US 5,710,347 A
- Document ID: US5710347A
- Status: Granted
- Kind: A
- Application number: 08/533,822
- Filed: 1995-09-26
- Granted: 1998-01-20
- Earliest claimed: 1995-09-26
- Assignees: Dai-Ichi Kogyo Seiyaku Co., Ltd.
- Inventors: Setsuo Nishibori; Hideaki Ohnishi; Tsuyoshi Furukawa
- Web page: https://patentgrep.com/patent/US5710347A

## CPC

- C07C 41/40: by change of physical state, e.g. by crystallisation
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS

## Abstract

This invention relates to a method of producing a high-melting powder of 2,2-bis›4'-(2",3"-dibromopropoxy)-3',5'-dibromophenyl!propane characterized by comprising a step of adding water to a solution of 2,2-bis›4'-(2",3"-dibromopropoxy)-3',5'-dibromophenyl!-propane in an organic solvent in the presence of a surfactant to give a water-in-oil emulsion and a step of removing the organic solvent from the emulsion in the presence of a crystal nucleus to induce crystallization to give an aqueous dispersion of 2,2-bis›4'-(2",3"-dibromopropoxy)-3',5'-dibromophenyl!propane. In accordance with this invention, crystallization is carried out in the state of an emulsion under assistance of a surfactant so that an ordinary stirrer can be used in production without resort to any special high-shear stirring equipment. Moreover, since a high-melting grade of 2,2-bis›4'-(2",3"-dibromopropoxy)-3',5'-dibromophenyl!propane is obtained as an aqueous dispersion, workability and safety in the subsequent processing are improved.

## Claims

### Claim 1

A method of producing a high-melting powder of 2,2-bis›4'-(2",3"-dibromopropoxy)-3',5'-dibromophenyl!propane characterized by comprising a step of adding water to a solution of 2,2-bis›4'-(2",3"-dibromopropoxy)-3',5'-dibromophenyl!propane in an organic solvent in the presence of a surfactant to give a water-in-oil emulsion and a step of removing the organic solvent from said emulsion in the presence of a crystal nucleus to induce crystallization to give an aqueous dispersion of 2,2-bis›4'-(2",3"-dibromopropoxy)-3',5'-dibromophenyl!propane.

### Claim 2 (depends on 1)

The method according to claim 1 wherein said surfactant is an acidic phosphoric ester type surfactant.

### Claim 3 (depends on 1, 2)

The method according to claim 1 or 2 wherein said crystallization is induced at a temperature of not over 80.degree. C.

### Claim 4 (depends on 1, 2)

A powder of 2,2-bis›4'-(2",3"-dibromopropoxy)-3',5'-dibromophenyl!propane having a melting point of not less than 100.degree. C. as obtained by the method claimed in claim 1 or 2.

### Claim 5 (depends on 1)

The method of claim 1, wherein the amount of surfactant is at least 0.05 wt. % relative to the amount of 2,2-bis›4'-(2",3"-dibromopropoxy)-3',5'-dibromophenyl!-propane and the amount of water is 20-100 wt. % relative to the amount of 2,2-bis›4'-(2",3"-dibromopropoxy)-3',5'-dibromophenyl!-propane.