Wiston Pamela R Lamshing

60546107, Apr 25, 2000

Jun 16, 1998

9/097930

Fu-Ming Lee - Katy TX
Wiston Lamshing - Katy TX
Randi Wright Wytcherley - Belgrade MT

HFM International, Inc. - Houston TX

C07C 51487

562487

A method and apparatus for preparing purified terephthalic acid and, optionally, isophthalic acid from mixed xylenes. The method of the present invention purifies the oxidation reactor effluent containing a mixture of terephthalic acid and isophthalic acid as well as minor amounts of 4-carboxybenzaldehyde (4-CBA), 3-carboxybenzaldehyde (3-CBA), and toluic acid isomers, to produce purified terephthalic acid and, optionally, purified isophthalic acid in an integrated process.

61405345, Oct 31, 2000

Jan 13, 1999

9/229789

Fu-Ming Lee - Katy TX
Wiston Lamshing - Katy TX
Randi Wright Wytcherley - Belgrade MT

HFM International, Inc. - Houston TX

C07C 5142
C07C 5143

562485

Disclosed is a method for preparing isophthalic acid from metaxylene and especially for purifying crude isophthalic acid (IPA) produced in the course of such method, or otherwise, from a liquid dispersion thereof also containing impurities selected from unreacted starting materials, solvents, products of side reactions and/or other undesired materials. The purifying portion of the method comprises the step of: (1) filtering the dispersion to form a crude IPA filter cake; (2) dissolving the filter cake in a selective crystallization solvent at an elevated temperature to form a solution; (3) crystallizing purified IPA from the solution in the crystallization solvent by reducing the temperature, or pressure, or both of the solution; (4) separating the crystallized purified IPA from the solution; and (5) re-dissolving or soaking the washed purified IPA cake at elevated temperature, to remove the final traces of the crystallization solvent and obtain the desirable particle sizes and shape. Preferably, the selective crystallization solvent is N-methyl pyrrolidone.

59292741, Jul 27, 1999

Jun 16, 1998

9/098060

Wiston Lamshing - Katy TX
Fu-Ming Lee - Katy TX
Randi Wright Wytcherley - Belgrade MT

HFM International, Inc. - Houston TX

C07C 51487

562487

A method for reducing carboxybenzaldehyde isomers in crude terephthalic and/or isophthalic acids is described. Crude TPA or IPA is dissolved in N-methyl pyrrolidone and is subsequently contacted with an oxidant, such as substantially anhydrous hydrogen peroxide, to convert the carboxybenzaldehyde isomer (4-CBA or 3-CBA) to TPA or IPA under moderate temperature and pressure conditions.

60138351, Jan 11, 2000

Dec 6, 1996

8/760890

Fu-Ming Lee - Katy TX
Wiston Lamshing - Katy TX

HFM International, Inc. - Clinton NJ

C07C 51487

562487

A method and apparatus for purifying crude terephthalic acid from a liquid dispersion thereof also containing impurities selected from unreacted starting materials, solvents, products of side reactions and/or other undesired materials is provided. The method comprises the steps of filtering the dispersion to form a crude terephthalic acid filter cake, dissolving the filter cake in a selective crystallization solvent at an elevated temperature to form a solution, crystallizing purified terephthalic acid from the solution in the crystallization solvent by reducing the pressure and temperature of the solution, and separating the crystallized purified terephthalic acid from the solution. According to the invention, the selective crystallization solvent is non-aqueous, non-corrosive and essentially non-reactive with terephthalic acid. Preferably, the selective crystallization solvent is N-methyl pyrrolidone.

58409688, Nov 24, 1998

Oct 31, 1997

8/962030

Fu-Ming Lee - Katy TX
Wiston Lamshing - Katy TX

HFM International, Inc. - Houston TX

C07C 5142

562486

A method and apparatus for purifying crude terephthalic acid from a liquid dispersion thereof also containing impurities selected from unreacted starting materials, solvents, products of side reactions and/or other undesired materials is provided. The method comprises the steps of filtering the dispersion to form a crude terephthalic acid filter cake, dissolving the filter cake in a selective crystallization solvent at an elevated temperature to form a solution, crystallizing purified terephthalic acid from the solution in the crystallization solvent by reducing the pressure and temperature of the solution, and separating the crystallized purified terephthalic acid from the solution. According to the invention, the selective crystallization solvent is non-aqueous, non-corrosive and essentially non-reactive with terephthalic acid. Preferably, the selective crystallization solvent is N-methyl pyrrolidone or dimethyl acetamide.

61138665, Sep 5, 2000

Nov 8, 1999

9/436786

Fu-Ming Lee - Katy TX
Wiston Lamshing - Katy TX

HFM International, Inc. - Clinton NJ

B01D 902

4222451

A method and apparatus for purifying crude terephthalic acid from a liquid dispersion thereof also containing impurities selected from unreacted starting materials, solvents, products of side reactions and/or other undesired materials is provided. The method comprises the steps of filtering the dispersion to form a crude terephthalic acid filter cake, dissolving the filter cake in a selective crystallization solvent at an elevated temperature to form a solution, crystallizing purified terephthalic acid from the solution in the crystallization solvent by reducing the pressure and temperature of the solution, and separating the crystallized purified terephthalic acid from the solution. According to the invention, the selective crystallization solvent is non-aqueous, non-corrosive and essentially non-reactive with terephthalic acid. Preferably, the selective crystallization solvent is N-methyl pyrrolidone.