| Patent Number |
Title Of Patent |
Date Issued |
| 6461700 |
Aromatic acid monomers, polymers, products and processes for their manufacture |
October 8, 2002 |
| Processes for producing aromatic monomers useful for forming polyesters are disclosed. Cost effective steps employed in the processes permit small amounts of process-related materials typically removed from monomer to remain in an aromatic monomer product. In many cases, the presence of |
| 6284920 |
Aromatic acid monomers, polymers, products and processes for their manufacture |
September 4, 2001 |
| Processes for producing aromatic monomers useful for forming polyesters are disclosed. Cost effective steps employed in the processes permit small amounts of process-related materials typically removed from monomer to remain in an aromatic monomer product. In many cases, the presence of |
| 5080798 |
Monitoring oligomers in a polymer |
January 14, 1992 |
| There are provided methods for monitoring the oligomeric content of prepolymers and polymers, which methods employ high-performance liquid chromatographic techniques. Typically, the methods of the present invention may be used to determine the oligomeric content of polyethylene terep |
| 4892972 |
Purification of crude terephthalic acid |
January 9, 1990 |
| Aqueous solutions of crude terephthalic acid are purified by hydrogenation in the presence of plural noble metal catalysts in separate layers. Initially, the solution to be purified is passed through a layer of ruthenium-on-carbon catalyst, rhodium-on-carbon catalyst, or platinum-on- |
| 4822527 |
Process for preparation of anthraquinones and fluorenones |
April 18, 1989 |
| A process is disclosed for producing cyclized aromatic compounds by the liquid-phase air oxidation of 2-methyl-substituted biphenyls and diphenylmethanes in an acetic acid medium in the presence of a cobalt-manganese-bromine catalyst or a zirconium-cobalt-manganese-bromine catalyst w |
| 4804501 |
Process for preparation of anthraquinones and fluorenones |
February 14, 1989 |
| A process is disclosed for producing cyclized aromatic compounds by the liquid-phase air oxidation of 2-methyl-substituted biphenyls and diphenylmethanes in an acetic acid medium in the presence of a cobalt-manganese-bromine catalyst or a zirconium-cobalt-manganese-bromine catalyst w |
| 4782181 |
Process for removal of high molecular weight impurities in the manufacture of purified terephtha |
November 1, 1988 |
| A process for producing fiber grade terephthalic acid is disclosed. In this process impurities having high molecular weight are eliminated by hydrogenation comprising the following steps: (a) treating an aqueous solution containing at least about 1 percent of said impure terephthalic |
| 4652674 |
Method for monitoring the fluorescence of 4-carboxy-p-terphenyl in crude terephthalic acid |
March 24, 1987 |
| A method is disclosed for separating and measuring the fluorescence of 4-carboxy-p-terphenyl in crude terephthalic acid formed by the liquid-phase oxidation of p-xylene in a solvent. |
| 4626598 |
Purification of terephthalic acid |
December 2, 1986 |
| An improved method for producing purified terephthalic acid by catalytic hydrogenation is disclosed. Control of the reduction of colored compounds during the production of purified terephthalic acid is effected by modulating solution hydrogen concentration during hydrogenation. |
| 4467111 |
Process for purification of crude terephthalic acid |
August 21, 1984 |
| A catalyst and process for purifying crude terephthalic acid wherein the catalyst is prepared by contacting a carbonaceous support with an aqueous solution of sodium tetranitropalladate. |
| 4467110 |
Process for purification of crude terephthalic acid |
August 21, 1984 |
| A process for producing a purified terephthalic acid which comprises reacting in a liquid phase a mixture of hydrogen and crude terephthalic acid, a palladium/rhodium catalyst on a porous carbonaceous support wherein the catalyst compound is prepared by adsorbing palladium on the sup |
| 4421676 |
Process for preparation of palladium on carbon catalysts used in the purification of crude terep |
December 20, 1983 |
| A catalyst and process for purifying crude terephthalic acid wherein the catalyst is prepared by contacting a carbonaceous support with an aqueous solution of sodium tetranitropalladate. |
| 4415479 |
Palladium on carbon catalyst for purification of crude terephthalic acid |
November 15, 1983 |
| A catalyst and process for purifying crude terephthalic acid wherein the catalyst comprises palladium metal crystallites deposited upon a carbon support wherein the catalyst is prepared by contacting a carbonaceous support with an aqueous solution of a palladium amine complex in the |
| 4394299 |
Palladium-rhodium catalyst for purification of crude terephthalic acid |
July 19, 1983 |
| A process for producing a purified terephthalic acid which comprises reacting in a liquid phase a mixture of hydrogen and crude terephthalic acid, a palladium/rhodium catalyst on a porous carbonaceous support wherein the catalyst compound is prepared by adsorbing palladium on the sup |
| 4352745 |
Liquid mobile phase |
October 5, 1982 |
| Aqueous solution of weak base (e.g. ammonium hydroxide) incompletely neutralized salt of an inorganic polyacid having three or more replaceable hydrogens also containing 2 to 10 weight percent dissolved alkanol or alkanenitrile buffered to a pH not exceeding 7.5 is a useful mobile phase |
