Basf Wyandotte Corporation

William M Herring

Joseph F Louvar

Stephen M Collins

Lee H Bergman

Kamal K Ladha

Michael A Capraro

Barry M Barkel

John J Evangelista

A continuous process for the preparation in at least one esterification reactor of phthalate diesters utilizing phthalic acid or anhydride and a stoichiometric excess of at least one saturated aliphatic alcohol containing about 4 to about 10 carbon atoms comprises (a) reaction of phthalic acid or anhydride with said alcohol in a reactor zone, (b) purification of the diester in a purification zone in which the reaction product is neutralized with an alkali metal hydroxide, i.e., sodium hydroxide, to separate the diester and the unreacted phthalic acid or anhydride together with said saturated alcohol utilized in the reaction, said reaction product is separated into an organic phase and an aqueous waste phase. The organic phase is washed with water, steam stripped, treated with activated charcoal and filtered to purify the diester product desired, (c) the aqueous phase containing monoester is separated from said organic phase in step (b) is purified by filtration to remove solid impurities, carbon treated to remove color bodies, and acidified and extracted with the same alcohol used in the esterification to obtain an organic phase which can be recycled to the reaction zone of the process without causing discoloration of the desired diester product of the process. In the monoester purification process, acidification is accomplished utilizing a strong organic acid, i.e., sulfuric acid, prior thereto or simultaneously with extraction utilizing the same alcohol used in the esterification process. Purification of the aqueous waste streams produced in the process can be accomplished using activated charcoal to remove organic wastes and precipitation of inorganic salts to remove inorganic impurities produced in the process.

Phthalic acid diester preparation with waste stream purification and

An improvement in the process for the removal of residual catalyst from polyether polyols is achieved by the use of a solvent wash and recovery system.

Filtration process for purifying polyols

Aqueous streams contaminated with minor amounts of organic materials are separated into an aqueous fraction which is concentrated with respect to the organic contaminants and a water fraction relatively free of the organic contaminants by a method which includes a unique combination of reverse osmosis (RO) and ultrafiltration (UF). The organic contaminants include substances having molecular weights of less than 10,000 which are soluble in the aqueous stream initially but have limited solubility ranges and are precipitated therefrom upon concentration. The contaminated aqueous stream is circulated from the high pressure compartment of a RO unit to the high pressure compartment of an UF unit, then to the low pressure compartment of the UF unit, and then back to the high pressure compartment of the RO unit. The contaminants are concentrated in the high pressure compartment of the RO unit, and a portion thereof is precipitated or otherwise rendered amenable to removal along with the UF concentrate upon passing the RO concentrate from the high pressure compartment of the RO unit to the high pressure compartment of the UF unit. Soluble organic contaminants remaining in the aqueous stream are removed in the UF permeate and are recycled back to the high pressure compartment of the RO unit for further concentration and precipitation, followed by recycling to the high pressure compartment of the UF unit for removal.

Method and apparatus for purifying aqueous streams contaminated with

Apparatus for producing a plurality of filter press diaphragms at any one time is disclosed herein. In one form of the invention the apparatus includes a sealed housing containing a plurality of sealed modules fed from a common header, to produce the diaphragms batch-wise. In another form of the invention, an indexing table is employed to produce the diaphragms continuously.

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Trenton, MI, United States of America

William M Herring