테레프탈산

테레프탈산 속성

테레프탈산 C화학적 특성, 용도, 생산

개요

Terephthalic acid is the organic compound with formula C₆H₄(COOH)₂. This colourless solid is a commodity chemical, used principally as a precursor to the polyester PET, used to make clothing and plastic bottles. Several million tones are produced annually. It is one of three isomeric phthalic acids.

화학적 성질

Terephthalic acid is a white crystalline solid. Soluble in alkaline solution, slightly soluble in hot ethanol, insoluble in water, ether, glacial acetic acid and chloroform, consequently up until around 1970 most crude terephthalic acid was converted to the dimethyl ester for purification. It sublimates when heated.

역사

Terephthalic acid came to prominence through the work of Winfield and Dickson in Britain around 1940. Earlier work by Carothers and coworkers in the United States established the feasibility of producing high molecular weight linear polyesters by reacting diacids with diols, but they used aliphatic diacids and diols. These made polyesters which were unsuitable to be spun into fibers. Winfield and Dickson found that symmetrical aromatic diacids yield high-melting, crystalline, and fiberforming materials; poly(ethylene terephthalate) (PET) has since become the largest volume synthetic fiber.

용도

Terephthalic acid (TPA) is a benzenepolycarboxylic acid with potential anti-hemorrhagic properties. It is a high-tonnage chemical, widely used in the production of synthetic materials, notably polyester fibers (poly-(ethylene terephthalate)).

주요 응용

1,4-benzenedicarboxylic acid is mainly used for the production of poly (ethylene terephthalate). Also production of plasticizer dioctyl phthalate (DOTP) and polyester plasticized agents. 1,4-benzenedicarboxylic acid and polyhydric alcohols have a condensation reaction withd iethylene glycol, triethylene glycol, glycerol, propylene glycol, butylene glycol, etc. preparation of the polyester plasticizer.

제조 방법

The major commercial route to terephthalic acid which is suitable for the direct preparation of poly(ethylene terephthalate) is from p-xylene:

p-Xylene is obtained largely from petroleum sources, being a product of the fractionation of reformed naphthas. The oxidation is carried out in the liquid phase. Typically, air is passed into a solution of p-xylene in acetic acid at about 200?? and 2 MPa (20 atmospheres) in the presence of a catalyst system containing cobalt and manganese salts and a source of bromide ions. The terephthalic acid produced contains only small amounts of impurities (mainly p-carboxybenzaldehyde), which are readily removed. The acid is dissolved in water at about 2500 e and 5 MPa (50 atmospheres) and treated with hydrogen (which converts the aldehyde to p-toluic acid). The solution is then cooled to 100?? and pure terephthalic acid crystallizes.

주요 응용

Virtually the entire world's supply of terephthalic acid and dimethyl terephthalate are consumed as precursors to polyethylene terephthalate (PET). World production in 1970 was around 1.75 million tones. By 2006, global purified terephthalic acid (PTA) demand had exceeded 30 million tonnes.
There is a smaller, but nevertheless significant, demand for terephthalic acid in the production of poly butylene terephthalate and several other engineering polymers.

생산 방법

Terephthalic acid is produced by oxidation of p-xylene by oxygen in air:
This reaction proceeds through a p-toluic acid intermediate which is then oxidized to terephthalic acid. In p-toluic acid, deactivation of the methyl by the electron withdrawing carboxylic acid group makes the methyl one tenth as reactive as xylene itself, making the second oxidation significantly more difficult . The commercial process utilizes acetic acid as solvent and a catalyst composed of cobalt and manganese salts, with a bromide promoter.

정의

ChEBI: Terephthalic acid is a benzenedicarboxylic acid carrying carboxy groups at positions 1 and 4. One of three possible isomers of benzenedicarboxylic acid, the others being phthalic and isophthalic acids. It is a conjugate acid of a terephthalate(1-).

일반 설명

White powder.

공기와 물의 반응

Insoluble in water.

반응 프로필

Terephthalic acid is a carboxylic acid. Terephthalic acid donates hydrogen ions if a base is present to accept them. This "neutralization" generates substantial amounts of heat and produces water plus a salt. Insoluble in water but even "insoluble" carboxylic acids may absorb enough water from the air and dissolve sufficiently in Terephthalic acid to corrode or dissolve iron, steel, and aluminum parts and containers. May react with cyanide salts to generate gaseous hydrogen cyanide. Will react with solutions of cyanides to cause the release of gaseous hydrogen cyanide. Flammable and/or toxic gases and heat are generated by reaction with diazo compounds, dithiocarbamates, isocyanates, mercaptans, nitrides, and sulfides. React with sulfites, nitrites, thiosulfates (to give H2S and SO3), dithionites (SO2), to generate flammable and/or toxic gases and heat. Reaction with carbonates and bicarbonates generates a harmless gas (carbon dioxide) but still heat. Can be oxidized by strong oxidizing agents and reduced by strong reducing agents. These reactions generate heat. May initiate polymerization reactions; may catalyze (increase the rate of) chemical reactions.

화재위험

Flash point data for Terephthalic acid are not available. Terephthalic acid is probably combustible.

Safety Profile

Moderately toxic by intravenous and intraperitoneal routes. Mildly toxic by ingestion. An eye irritant, Can explode during preparation. When heated to decomposition it emits acrid smoke and irritating fumes.

잠재적 노출

TPA is used primarily in the production of polyethylene terephthalate polymer for the fabrication of polyester fibers and films. A high-volume production chemical in the United States.

Purification Methods

Purify the acid via the sodium salt which, after crystallisation from water, is re-converted to the acid by acidification with mineral acid. Filter off the solid, wash it with H2O and dry it in a vacuum. The S-benzylisothiuronium salt has m 204o (from aqueous EtOH). [Beilstein 9 IV 3301.]

비 호환성

Combustible; dust may form an explosive mixture with air. Compounds of the carboxyl group react with all bases, both inorganic and organic (i.e., amines) releasing substantial heat, water and a salt that may be harmful. Incompatible with arsenic compounds (releases hydrogen cyanide gas), diazo compounds, dithiocarbamates, isocyanates, mercaptans, nitrides, and sulfides (releasing heat, toxic and possibly flammable gases), thiosulfates and dithionites (releasing hydrogen sulfate and oxides of sulfur). Incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides.

폐기물 처리

Dissolve or mix the material with a combustible solvent and burn in a chemical incinerator equipped with an afterburner and scrubber. All federal, state, and local environmental regulations must be observed.

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테레프탈산 공급 업체

공급자	전화	이메일	국가	제품 수	이점
Jinan Qinmu Fine Chemical Co.,Ltd.	+8618660799346	sales@qinmuchem.com	China	1009	58
Nanjing Deda New Material Technology Ltd.	+8613223281135	niki@njdeda.com	China	76	58
Hebei Mojin Biotechnology Co., Ltd	+8613288715578	sales@hbmojin.com	China	12456	58
Shandong Juchuang Chemical Co., LTD	+86-18885615001 +86-18885615001	admin@juchuangchem.com	China	387	58
Hebei Kangcang new material Technology Co., LTD	+8619133911216	fanfan@kangcang.com.cn	China	340	58
hebei hongtan Biotechnology Co., Ltd	+86-86-1913198-3935 +8617331935328	sales03@chemcn.cn	China	951	58
Capot Chemical Co.,Ltd.	571-85586718 +8613336195806	sales@capotchem.com	China	29797	60
Henan Tianfu Chemical Co.,Ltd.	+86-0371-55170693 +86-19937530512	info@tianfuchem.com	China	21691	55
Shanghai Time Chemicals CO., Ltd.	+86-021-57951555 +8617317452075	jack.li@time-chemicals.com	China	1807	55
ATK CHEMICAL COMPANY LIMITED	+undefined-21-51877795	ivan@atkchemical.com	China	32480	60

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