Terephthalic Acid Polyester

Isophthalic/Terephthalic Acid Polyester Typically, isophthalic acid is reacted in a two-stage process with glycols such as propylene or neopentyl glycol and then with maleic anhydride. The crosslinked, fully cured isophthalic-based composites exhibit good weathering resistance and good corrosion resistance to acid media. 

Esterification of terephthalic acid Polyester film Export ... 

Dioctyltin diisooctylthioglycollate catalyst, PU two-pack coatings Dibutyltin bis (laurylmercaptide) catalyst, PU elastomers Ferric acetylacetonate N-Hydroxyethy I pi perazi ne catalyst, purified terephthalic acid polyesters Manganese acetate (ous) catalyst, PVC suspension polymerization Lauroyl peroxide catalyst, pyridine synthesis Cobaltocene... 

T100 Terephthalic acid, polyester with 1,5-pentanediol... 

Terephthaldoxime, //,// -[4,4-diphenyl(methane)] bismaleimide reaction, 514 Terephthalic acid, polyesters use, 494 Termination rate constant, MA-methyl methacrylate copolymerization, 281 Terpenes... 

Though a variety of aliphatic polyesters are available, the major commercial thermoplastic polyesters are based on the aromatic dicarboxylic acid, terephthalic acid. The terephthalic acid polyesters prepared from the lower glycols are tough crystalline solids. The isophthalic acid derivatives have lower T s... 

An important function of nomenclature is for the storage and retrieval of information. It is therefore of interest to examine, with the help of this example, the practice of Chemical Abstracts— the prime chemical search tool of the Western world—which, except for a small number of macromolecular materials of well-defined structure, indexes polymers on the basis of their supposed monomers or precursors rather than as substances in their own right. Until 1971," the substances in question were indexed under terephthalic acid, polyester with 1,4-butanediol and polytetramethylene glycol . Subsequently, partial use has been made of lUPAC-recommended structure-based nomenclature, leading to a cycle of expressions of the type 1,4-benzenedicarboxylic acid, polymer with 1,4-butanediol and a-hydro-cu-hydroxypoly(oxy-l,4-butanediyl) , permuted to commence with each reactant in turn. It will be noted that these terms presuppose what is not the case in practice, that terephthalic acid (1,4-benzenedicarboxylic acid) is an immediate precursor of the polymers. However, further search will show the polymers located under a cycle of names of the type poly(oxy-1,4-butanediyl), a-hydro-m-hydroxy, polymer with 1,4-butanediol and dimethyl 1,4-benzenedicar-boxylate , and will reveal that the assigned Chemical Abstracts Registry numbers, which are intended... 

Condensation polymerization differs from addition polymerization in that the polymer is formed by reaction of monomers, each step in the process resulting in the elimination of some easily removed molecule (often water). E.g. the polyester polyethylene terephthalate (Terylene) is formed by the condensation polymerization (polycondensation) of ethylene glycol with terephthalic acid ... 

Those polymers which are the condensation product of two different monomers are named by applying the preceding rules to the repeat unit. For example, the polyester formed by the condensation of ethylene glycol and terephthalic acid is called poly(oxyethylene oxyterphthaloyl) according to the lUPAC system, as well as poly (ethylene terephthalate) or polyethylene terephthalate. 

Purified terephthalic acid and dimethyl terephthalate are used as raw materials for the production of saturated polyesters. During 1993, the combined worldwide production of purified terephthafic acid plus dimethyl terephthalate exceeded 14 x 10 t (42), which is 80% of the total benzenepolycarboxyfic acid production. Terephthafic acid is also produced ia technical or cmde grades which are not pure enough for manufacture of poly(ethylene terephthalate). In almost all cases, the technical-grade material is immediately converted to purified terephthafic acid or dimethyl terephthalate, which together are the articles of commerce. 

Manufacture and Processing. Terephthalic acid and dimethyl terephthalate did not become large-volume industrial chemicals until after World War II. Imperial Chemical Industries in the United Kingdom in 1949 and Du Pont in the United States in 1953 commercialized fibers made from poly(ethylene terephthalate). Dimethyl terephthalate and ethylene glycol were the comonomers used by both companies (see Fibers, polyester). 

Like terephthalic acid, isophthalic acid is used as a raw material in the production of polyesters. Much of the isophthaUc acid is used for unsaturated polyesters, whereas terephthaUc acid is used almost exclusively in saturated (thermoplastic) polyesters. However, a considerable amount of isophthaUc acid is used as a minor comonomer in saturated polyesters, where the principal diacid is terephthaUc acid. The production volume of isophthaUc acid is less than 2% that of terephthahc. IsophthaUc acid was formerly produced in technical or cmde grades and only a small amount was purified. Now, however, it is all purified to a standard similar to that of terephthahc acid. 

Polyester—any long-chain synthetic polymer composed of at least 85% hy weight of an ester of a dihydric alcohol and terephthalic acid (p—HOOC—C6H4—COOH). 2.2-7.8 E-G G G-F G G 1.38 300... 

Another recent development is the preparation of a polyester-polycarbonate copolymer. The polymers involve a polyester component based on the reaction between bis-phenol A and iso- or terephthalic acid with the carbonate component arising from the reactions described in Section 20.3 (see Section 20.9). 

From the above comments it will be expected that terephthalic acid would be an important intermediate in the production of linear crystallisable polyesters, and so it has proved. 

As with poly(ethylene terephthalate) PBT-based copolymers have been introduced to overcome some of the deficiencies of the homopolymer. For example, the rather low notched impact strength of unreinforced grades has been overcome by partial replacement of the terephthalic acid with a longer chain aliphatic dicarboxylic acid. Improved toughness has also been obtained by grafting about 5% of ethylene and vinyl acetate onto the polyester backbone. 

The polyester made by reacting hydroquinone with terephthalic acid also melted above 500°C. That from bis-phenol A and 4,4 -(2,2-butylidene)dibenzoic acid is said to be stable in nitrogen to above 400°C. 

For the liquid crystal polyesters the basic structural units are derived from such materials as 5-hydroxybenzoic acid, terephthalic acid and hydroquinone. Some basic sequences from such materials are shown in Figure 25.25. 

The phthalic acid and benzoic acid are reacted to form a reaction intermediate. The reaction intermediate is dissolved in sulfuric acid, which precipitates terephthalic acid (TPA). Fifty percent of the TPA is sold as a product and 50 percent is further processed at your facility into polyester fiber. The TPA Is treated with ethylene glycol to form an intermediate product, which is condensed to polyester. 

Your company manufactures terephthalic acid, a listed chemical, both for sale/distribution as a commercial product and for on-site use/processino as a feedstock in the polyester process. Because it is a reactant, it is also processed. See Figure D for how this information would be reported in Part III, Section 3 of Form R. 

Paraxylene is used to make terephthalic acid, the raw material for manufacturing polyester fibers, such as Dacron, Kodel, Fortrel and Terylene. 

The crude terephthalic acid is cooled and crystallized. For polyester grade, it must be purified to 99.9 per cent by subsequent recrystallization. 

The carboxylic acid produced in the greatest fflnounts is 1,4-benzenedicarboxylic acid (terephthalic acid). About 5 X 10 Ib/year- is produced in the United States as a starting material for the preparation of polyester fibers. One important process converts p-xylene to terephthalic acid by oxidation with nitric acid ... 

Terephthalic acid is an important monomer for producing polyesters. The main route for obtaining the acid is the catalyzed oxidation of paraxylene. It can also be produced from benzoic acid by a disproportionation reaction of potassium benzoate in the presence of carbon dioxide. Benzene is the coproduct ... 

The carhonylation reaction of toluene with carhon monoxide in the presence of HF/BF3 catalyst produces p-tolualdehyde. A high yield results (96% based on toluene and 98% based on CO). p-Tolualdehyde could be further oxidized to terephthalic acid, an important monomer for polyesters ... 

Another approach is to use an easily oxidized substance such as acetaldehyde or methylethyl ketone, which, under the reaction conditions, forms a hydroperoxide. These will accelerate the oxidation of the second methyl group. The DMT process encompasses four major processing steps oxidation, esterification, distillation, and crystallization. Figure 10-16 shows a typical p-xylene oxidation process to produce terephthalic acid or dimethyl terephthalate. The main use of TPA and DMT is to produce polyesters for synthetic fiber and film. 

Polybutylene terephthalate (PBT) is another thermoplastic polyester produced by the condensation reaction of terephthalic acid and 1,4-butanediol ... 

Polyesters are the most important class of synthetic fibers. In general, polyesters are produced by an esterification reaction of a diol and a diacid. Carothers (1930) was the first to try to synthesize a polyester fiber by reacting an aliphatic diacid with a diol. The polymers were not suitable because of their low melting points. However, he was successful in preparing the first synthetic fiber (nylon 66). In 1946, Whinfield and Dickson prepared the first polyester polymer by using terephthalic acid (an aromatic diacid) and ethylene glycol. 

Melt spinning polyesters is preferred to solution spinning because of its lower cost. Due to the hydrophobic nature of the fiber, sulfonated terephthalic acid may be used as a comonomer to provide anionic sites for cationic dyes. Small amounts of aliphatic diacids such as adipic acid may also be used to increase the dyeability of the fibers by disturbing the fiber s crystallinity. 

A similar oxidation is employed industrially for the preparation of the terephthalic acid used in the production of polyester fibers. Approximately 5 million tons per year of p-xylene are oxidized, using air as the oxidant and Co(lll) salts as catalyst. 

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