摘要:
Processes are disclosed for recovery and purification of dibasic aromatic acids from waste polyester film, fiber, bottles, manufacturing residues, and other manufactured articles. The processes comprises: depolymerizing polyester resin in a solvent under conditions suitable for hydrolysis of ester bonds to obtain a mixture containing a solution of aromatic acid and impurities consisting of alcohol and/or other components of the resin; burning impurities in a liquid-phase oxidation with an oxygen-containing gas in the presence of an oxidation catalyst at elevated pressures and temperatures, to obtain an oxidation product containing the desired aromatic acid; and crystallizing and separating from the oxidation system a resulting crude dibasic aromatic acid. Crude acid is, optionally, hydrogenated in an aqueous solution at elevated temperatures and pressures in the presence of hydrogen and an insoluble metal-containing catalyst, which is thereupon separated from the aqueous solution, and purified dibasic aromatic acid recovered by crystallization and mechanical separation from the aqueous solution. Purified terephthalic acid has, typically, a L*-value in a range of from about 95 to about 100, an a*-value in a range of from about -1 to about +1, and a b*-value in a range of from about 0.5 to about 2.
摘要:
Processes are disclosed for recovery of hydrogen bromide from one or more alkyl bromide compounds by hydrolyzing the alkyl bromide compounds to hydrogen bromide and corresponding alcohols, and simultaneously separating at least the alcoholic products of hydrolysis from aliphatic monocarboxylic acid solvent component. Also disclosed are process for preparing aromatic carboxylic acids by the exothermic, liquid-phase oxidation of an aromatic feedstock compound wherein the energy produced by the exothermic oxidation is efficiently recovered, and uses of water produced during the preparation of aromatic carboxylic acids are efficiently integrated into the process.
摘要:
A process for the manufacture of aromatic dicarboxylic acids is disclosed using a low bromine to metals ratio facilitated by the use of cerium along with the cobalt and manganese catalyst. Aromatic dicarboxylic acids such as terephthalic acid are useful in the manufacture of fiber, films, bottles and molded products.
摘要:
The synthesis of dimethyl-1,5-naphthalenedicarboxylate and polymers and articles formed therefrom is disclosed, as well as applications for dimethyl-1,5-naphthalenedicarboxylate, its corresponding acid 1,5-NDA, and various synthesis intermediates.
摘要:
Processes using a titanium dioxide-supported purification catalyst are disclosed for purification of relatively impure dicarboxylic aromatic acid produced by liquid-phase oxidation of a suitable benzene or naphthalene having two oxidizable ring substituents, and/or by recovery from polyester resin comprising repeating units of the dicarboxylic aromatic acid residue and repeating units of dihydric alcohol residue. Purification comprises passing an aqueous solution of dicarboxylic aromatic acid with small amounts of organic impurities consisting of oxygen-containing aromatic co-products of oxidation and/or other organic components, through a particulate bed of purification catalyst comprising a noble metal on a titanium dioxide support under conditions suitable for decarbonylation of organic impurities. Generally, at least one weight percent of the titanium dioxide support is in the rutile crystalline phase. Optionally, effluent aqueous solution from the bed containing noble metal on the titanium dioxide support is passed through a subsequent particulate bed of another purification catalyst in the presence of a molecular hydrogen-containing gas. Hydrogenation of the aqueous solution subsequent to decarbonylation further reduces organic impurities in dicarboxylic aromatic acid recovered by crystallization and separation from the aqueous solution. The invention provides improved processes for preparation of purified terephthalic acid wherein purified terephthalic acid product is recovered from its mother liquor while maintaining temperatures within a range downward from about 100.degree. C. to about 25.degree. C. and pressures near or at atmospheric pressure.
摘要:
Processes using a titanium dioxide-supported purification catalyst are disclosed for purification of relatively impure dicarboxylic aromatic acid produced by liquid-phase oxidation of a suitable benzene or naphthalene having two oxidizable ring substituents, and/or by recovery from polyester resin comprising repeating units of the dicarboxylic aromatic acid residue and repeating units of dihydric alcohol residue. Purification comprises passing an aqueous solution of dicarboxylic aromatic acid with small amounts of organic impurities consisting of oxygen-containing aromatic co-products of oxidation and/or other organic components, through a particulate bed of purification catalyst comprising a noble metal on a titanium dioxide support under conditions suitable for decarbonylation of organic impurities. Generally, at least one weight percent of the titanium dioxide support is in the ruffle crystalline phase. Optionally, effluent aqueous solution from the bed containing noble metal on the titanium dioxide support is passed through a subsequent particulate bed of another purification catalyst in the presence of a molecular hydrogen-containing gas. Hydrogenation of the aqueous solution subsequent to decarbonylation further reduces organic impurities in dicarboxylic aromatic acid recovered by crystallization and separation from the aqueous solution.
摘要:
Processes are disclosed for recovery and purification of dibasic aromatic acids or esters thereof from waste polyester film, fiber, bottles, manufacturing residues, and other manufactured articles. The processes comprise: depolymerization of polyester resin in a liquid solvent under conditions of elevated temperature and pressure suitable for opening of ester bonds to form a solution of dibasic aromatic acid or ester, polyol, organic impurities, and other components of the resin; crystallization of the dibasic aromatic acid or ester from the solution by flash crystallization to form a vapor containing a major mount of the polyol and solvent, and a slurry of dibasic aromatic acid or ester crystals in mother liquor; separation of crude dibasic aromatic acid or ester from the mother liquor; crystallization of retained organic impurities from the mother liquor solution by flash crystallization to a pressure in a range downward from about one atmosphere to form a slurry of mother liquor solids; recovery of mother liquor solids from the slurry; and recycle of the recovered mother liquor solids to the depolymerization.
摘要:
Economical processes are disclosed for recovery and refining of valuable nitrogen-containing organic compounds formed by catalytic oxidation of least one feed compound selected from the group consisting of propane, propylene, isobutane and isobutylene in the presence of ammonia to produce a gaseous. Processes of the invention include quenching the gaseous reactor effluent with an aqueous quench liquid; forming an aqueous solution comprising the corresponding unsaturated mononitrile, hydrogen cyanide and other organic co-products; and using an integrated sequence of distillations and phase separations to recover for recycle of a useful aqueous liquid, and obtain the desired nitrogen-containing products. According to the invention aqueous solutions are fractionated in an integrated system of multi-stage columns while an effective polymerization inhibiting amount of at least one member of a preselected class of p-phenylenediamine compounds is maintained therein.
摘要:
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 the process-related materials left in the monomer product by the cost effective process steps can enhance the performance of the monomer in certain applications. Aromatic monomer products and polymers produced therefrom having these advantages also are disclosed, as well as products such as pasteurizable bottles made from these polymers.
摘要:
Ceramic materials comprising steatite or forsterite which are highly dense in nature may be prepared by admixing a hydrolyzed alcoholic solution of a silicon alkoxide with a solution prepared by adding an organomagnesium compound to an alcohol at gelation conditions. Following the formation of the gel, it is then dried at an elevated temperature of from about 300.degree. to about 500.degree. C. to remove volatile compounds as well as to decompose any remaining organic compounds and thereafter the powder is pressed into a desired shape. The formed shape is then sintered at a temperature in the range of from about 850.degree. to about 950.degree. C. to form a densified ceramic.