Dai-ichi Kogyo Seiyaku Co., Ltd.

Hideaki Ohnishi

Setsuo Nishibori

Tsuyoshi Furukawa

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.

Method of producing a high-melting powder of

The invention relates to a process for producing tris(tribromoneopentyl) phosphate (TTBNPP), which is of value as a flame retardant. The process comprises reacting tribromoneopentyl alcohol with a phosphorus oxyhalide in the presence of anhydrous aluminum chloride as catalyst in an organic solvent to give tris(tribromoneopentyl) phosphate characterized in that a basic magnesium salt is added to the reaction mixture at the completion of the reaction. Compared with the conventional production technology, the process of the invention is conducive to high production safety and insures a high yield and a high recovery rate through a simplified procedure.

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Shiga, Japan

Hideaki Ohnishi