Terephthaloyl chloride

Description

Terephthaloyl chloride (1,4-benzenedicarbonyl chloride), the acid chloride of terephthalic acid, is used primarily to make specialty polymers, primarily aromatic polyamides, or aramids. In 1965, inventors at DuPont developed the aramid Kevlar, a copolymer of terephthaloyl chloride and p-phenylenediamine. Its first use was as a replacement for steel in racing tires.

Chemical properties

monoclinic crystals or white crystalline flakes. Soluble in ethanol and organic solvents.

The Uses of Terephthaloyl chloride

Terephthaloyl chloride acts as a monomer with p-phenylenediamine used in the preparation of polymer viz. poly paraphenylene terephthalamide. It is an active component in performance polymers and aramid fibers, which gives flame resistance, chemical resistance, temperature stability, light weight, and very high strength. It is also used as an effective water scavenger, utilized to stabilize isocyanates and urethane prepolymers. Further, it is used in the preparation of liquid crystalline thermosets by thermal cyclotrimerization of dicyanate compounds of ring substituted bis(4-hydroxyphenyl) terepthalates. In addition to this, it is involved in the condensation reaction with difunctional alfa, μ-diaminopolystyrene to get chain-extended polystyrene containing amide bonds along the polymer backbone.

The Uses of Terephthaloyl chloride

Terephthaloyl chloride and Isophthaloyl dichloride have many similar uses as monomers for the synthesis of specialty fibers and as raw materials for polymers such as polyamides and polyesters. Dyemanufacture; synthetic fibers, resins, films; UV absorption; pharmaceuticals; rubber chemicals; cross-linking agent for polyurethanes and polysulfides.

Preparation

Synthesis of terephthaloyl chloride by thionyl chloride method: terephthalic acid is mixed with thionyl chloride, refluxed at 80℃ for 10-12h, then the thionyl chloride is evaporated, and the resulting crude product is distilled under reduced pressure to obtain the finished product.

General Description

Terephthaloyl chloride undergoes condensation reaction with difunctional α,ω-diaminopolystyrene to yield chain-extended polystyrene containing amide bonds along the polymer backbone. It undergoes interfacial reaction with bovine serum albumin to form thin cross-linked films.

Hazard

Skin irritant.

Flammability and Explosibility

Non flammable

Safety Profile

Moderately toxic by ingestion. Corrosive. Combustible when exposed to heat or flame. When heated to decomposition it emits toxic fumes of Cl-. See also CHLORIDES.

Purification Methods

Crystallise the acid chloride from dry hexane. [Beilstein 9 IV 3318.]