Dimethyl terephthalate 1,4-butanediol polyester

Commercial thermoplastic polyesters are synthesized in a similar way by the reaction of a relatively high molecular-weight polyether glycol with butanediol and dimethyl terephthalate (14,15). The polyether chain becomes the soft segment in the final product, whereas the terephthaUc acid—butanediol copolymer forms the hard crystalline domains. 

Polyester-Polyether Thermoplastic Elastomers Dimethyl Terephthalate/l,4-Butanediol/Dihydroxy-Poly(oxytetramethylene)... 

Terephthalic acid and dimethyl terephthalate are used to produce polyester fibers, polyester resins, and polyester film. Terephthalic acid or dimethyl terephthalate is usually reacted with ethylene glycol to give polyethylene terephthalate) but sometimes it is combined with 1,4-butanediol to yield poly (butylene terephthalale). Polyester fibers are used in the textile industry. Films find applications as magnetic tapes, electrical insulation, photographic film, packaging, and polyester bottles. 

AO containing various phenolic moieties were prepared by transesterification in the presence of tetraalkyl titanates. Randomly distributed -active moieties are characteristic of 140 (only the hard polyester segment is given) prepared from dimethyl terephthalate, 1,4-butanediol, poly(tetramethylene oxide)diol and dimethyl 5-(3,5-di-tm-butyl-4-hydroxybenzenepropaneamido)isophthalate [181]. The mentioned polymeric AO was used for stabilization of polyether-polyester elastomers. A partial attachement of tetrakis[methylene 3(3,5-di-tert-butyl-4-hydroxy-phenyl)propionate]methane (3) via transesterification reaction was expected in the synthesis of another polyether-polyester elastomer by [182]. A reversible redox polyester was formed from 2,5-bis(2-hydroxyethyl)hydroquinone and dichlorides of aliphatic dicarboxylic acids [137],... 

A segmented polyether-polyester (H49) was synthesized via melt transesterification from 1-4 dimethyl terephthalate, 1-4 butanediol and poly(tetramethylene ether)glycol ... 

Hytrel is a random segmented polyester made (60. 61) by the equilibrium melt transesterification of dimethyl terephthalate (DMT), 1,4-butanediol, and polytetramethyleneglycol (PTMEG) (Reaction 16) ... 

Poly(butylene terephthalate) is a highly crystalline thermoplastic polyester that is manufactured by condensation polymerization of 1,4-butanediol and dimethyl terephthalate in the presence of tetrabutyl... 

Definition Crystalline thermoplastic polyester resin formed in a transesterification reaction between 1,4-butanediol and dimethyl terephthalate good heat stability, mech. props., elec, insulation, surf, finish, water ab rption and grease/oil/petrol. resist. 

In addition, there are thermoplastic polyester elastomers. These are produced by equilibrium melt transesteiification of dimethyl terephthalate, 1,4-butanediol, and a poly(tetramethylene oxide) glycol (molecular weight about 10(X)). Because equilibrium conditions exist in the melt, the products are random copolymers ... 

Poly(ethylene terephthalate), the lowest cost and most commonly used polyester, is produced using ethylene glycol (EG) and either dimethyl terephthalate (DMT) or terephthahc acid (TPA) (see Table 7.1). Processes using DMT were commercialized first, but when very pure TPA became available, TPA processes became more economical for large-scale fiber production. Poly(butylene terephthalate) (PBT), produced fi-om 1,4 butanediol and DMT, is another commercially important polyester, which is used for computer housings and many other molded products. Poly(trimethylene terephthalate) (PTT), made from TPA and 1,3 propanediol, is a relatively new commercial polyester, that shows promise for... 

To produce a terephtalate adipate copolyester, dimethyl terephthalate, adipic acid, 1,4-butanediol, and glycerol are mixed together with tetrabutyl orthotitanate as a catalyst (44). The reaction mixture is then heated to a temperature of 180°C for 6 h and at 240°C. The excess dihydroxy compound can be removed by distillation in vacuo. Then hexamethylene diisocyanate is slowly added to the mixture. The diisocyanate act as chain extenders. From this material, a biodegradable polyester film can be produced. In addition, the s mtheses of related copolyesters have been described in detail (45). It has been found that the addition of chalk can achieve an additional improvement in the biodegradability. 

Polybutylene terphthalate (PBT) is a semicrystalline thermoplastic polyester considered as a medium performance engineering polymer. It is produced industrially in a two-step batch or continuous process. The first step involves the transesterification of dimethyl terephthalate (DMT) with 1,4-butanediol (BDO) to produce hydrobutyl terephtlate (bis-HBT) at a temperature of 200 C. The second step consists to the polycondensation of bis-HBT at 250 C to yield PBT. It exhibits both excellent electrical properties and chemical resistance. When reinforced with glass fibers, it has improved stiffness and mechanical strength. Typical uses include connectors, capacitors and cable enclosures. PBT is also used in hot appliances such as iron and kettles. 

PBT can generally be produced by reacting 1,4-butanediol with an aromatic diester - dimethyl terephthalate (DMT) or diacid -terephthalic acid (TEA), in the presence of a polyesterification catalyst. Methanol is the major byproduct in the former route, while the water is the major byproduct in the latter route. Although polycondensation to high conversions implicitly requires stoichiometric balance of reacting groups, industrial processes for manufacturing polyesters such as PBT involve initial use of excess BD, which is later removed and recycled in the process. At the time when Pilati published his review [18], most publications described the trans-esterification between BD and DMT. Since that time, the majority of patents have been related to the direct polyesterification of BD by TEA [23-28]. 

Transesterifications, also termed as ester exchange or ester interchange reactions, include hydroxy-ester, carboxy-ester, and ester-ester reactions. Hydroxy-ester interchange (called alcoholysis) plays a predominant role in most industrial preparations of aliphatic-aromatic polyesters such as PBT. The original industrial s)mthesis of PBT is based on a relatively expensive two-step melt pol)mierization reaction between dimethyl terephthalate and excess 1,4-butanediol of approximately 30-50 %, in the presence of catalyst [15-20]. V th respect to the catalyst used for the synthesis of PBT, in contrast to the s)mthesis of PET, one and the same metal complex is used for both reaction steps of the process. Usually tetra-alkoxy titanates are applied, often in combination with a particular cocatalyst. The reaction proceeds in two steps transesterification and polycondensation (Figure 5.2). The first, transesterification step, which is generally performed in an inert atmosphere to prevent oxidative side reactions, involves the conversion of the methyl... 

The second largest volume polyester is polybutylene terephthalate, PBT, made from dimethyl terephthalate and 1,4-butanediol with a titanium alkox-ide catalyst. Butanediol can be prepared from acetylene and formaldehyde followed by reduction of the triple bond. 

In addition, other semiaromatic polyesters including poly (butylene terephthalate), PBT, were described. PBT prepared by the transesterification reaction of dimethyl terephthalate and butanediol. PBT exhibits a T, of 45°C and a T of 225°C. The struc-... 

In general, nonabsorbable sutures can retain their tensile strength longer than 2 months [113]. The synthetic polymers used to make nondegradable sutures include polypropylene (PP), polyamides, polyesters such PET and polybutylene terephthalate (PBT), and polyether-ester based on poly(tetramethylene glycol), 1,4-butanediol, and dimethyl terephthalic acid [114]. The base polymer and filament configuration for common nonabsorbable sutures are summarized in Table 8.2. 

In contrast to most aliphatic polyesters, aromatic polyesters like PET provide excellent material properties [50]. To combine good material properties with biodegradability, aliphatic/aromatic copolyesters have been developed. Several major polyester producers in Europe and the United States have recently begun marketing aliphatic/aromatic copolyesters for biodegradable applications. BASF markets a product, Ecoflex , which is a copolyester of butanediol, adipic acid, and dimethyl terephthalate. Eastman s Eastar Bio Copolyester 14766 is a similar aliphatic/aromatic copolyester. DuPont markets a modified PET known as Biomax . 

Polybutylene terephthalate (PBT) is a semi-crystalline saturated polyester, which has been produced since 1942. PBT is made by the polycondensation of terephthalic acid or dimethyl terephthalate with 1,4-butanediol in the presence of a catalyst. Terephthalic acid, dimethyl terephthalate and 1,4-butanediol are derived from petrochemicals such as xylene and acetylene. The polymer is noted for high stiffness and strength, high resistance to heat, low water absorption and high dimensional stability. It has moderate chemical resistance and low resistance to strong acids and bases. 

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... 

More recently, McCarthy [20] prepared polyoxyalkylene-6-polyester TPEs by polycondensing dimethyl terephthalate with a 50/50 mixture of an a,o -dihydroxy-polyether and 1,4-butanediol (Scheme 16). 

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