Hoechst Celanese Corporation

James L Ragan

Charles B Hilton

Bennett C Ward

Carrie A Feeney

Thomas M Kenesson

Edward M De La Garza

B Frank Wood

Michael R Ahern

Thomas L Grantland

Gregory M Adams

Ida L Jones

Kan J Tsai

Processes for recovering 4,4'-dimethyl bibenzoate (DMBB) from byproduct streams of dimethyl terephthalate (DMT) production are disclosed. The byproduct streams are treated to produce an overhead stream which includes DMBB. In one aspect of the invention, the overhead product stream is added to an organic solvent under conditions sufficient to rapidly form a suspension of crystallized DMBB. In another aspect of the invention, the overhead is dissolved in an appropriate organic solvent and cooled to form a suspension of DMBB crystals in the solvent. A portion of the suspension is removed, and the remaining portion of the suspension centrifuged to recover DMBB crystals. In still another aspect of the invention, the overhead stream is treated with an organic solvent to form a slurry of DMBB crystals, and the resultant slurry thermally treated to increase the concentration of DMBB crystals therein while also solubilizing any organic contaminants.

Processes for cystallizing 4, 4'-dimethyl bibenzoate (DMBB) recovered

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Corpus Christi, TX, United States of America

James L Ragan