The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 20, 1998
Filed:
Sep. 26, 1995
Dai-Ichi Kogyo Seiyaku Co., Ltd., Kyoto, JP;
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.