Terephthalsure

Gefahreninformationscode (GHS)

• Bildanzeige (GHS)

  

• Alarmwort

  Achtung

• Gefahrenhinweise

  H315：Verursacht Hautreizungen.

  H319：Verursacht schwere Augenreizung.

  H335：Kann die Atemwege reizen.

• Sicherheit

  P261：Einatmen von Staub vermeiden.

  P264：Nach Gebrauch gründlich waschen.

  P264：Nach Gebrauch gründlich waschen.

  P304+P340：BEI EINATMEN: Die Person an die frische Luft bringen und für ungehinderte Atmung sorgen.

  P305+P351+P338：BEI KONTAKT MIT DEN AUGEN: Einige Minuten lang behutsam mit Wasser spülen. Eventuell vorhandene Kontaktlinsen nach Möglichkeit entfernen. Weiter spülen.

  P321：Besondere Behandlung

  P332+P313：Bei Hautreizung: Ärztlichen Rat einholen/ärztliche Hilfe hinzuziehen.

  P337+P313：Bei anhaltender Augenreizung: Ärztlichen Rat einholen/ärztliche Hilfe hinzuziehen.

  P405：Unter Verschluss aufbewahren.

Terephthalic acid Chemische Eigenschaften,Einsatz,Produktion Methoden

• ERSCHEINUNGSBILD

  WEISSES KRISTALLINES PULVER.

• PHYSIKALISCHE GEFAHREN

  Staubexplosion der pulverisierten oder granulierten Substanz in Gemischen mit Luft möglich.

• CHEMISCHE GEFAHREN

  Reagiert sehr heftig mit starken Oxidationsmitteln.

• ARBEITSPLATZGRENZWERTE

  TLV: 10 mg/m?(als TWA); (ACGIH 2005).
  MAK: 0,1 mg/m?(Einatembare Fraktion); Spitzenbegrenzung: überschreitungsfaktor I(2); Schwangerschaft: Gruppe C; (DFG 2006).
  

• AUFNAHMEWEGE

  Aufnahme in den Körper durch Inhalation des Aerosols und durch Verschlucken.

• INHALATIONSGEFAHREN

  Verdampfen bei 20°C vernachlässigbar; eine belästigende Partikelkonzentration in der Luft kann jedoch beim Dispergieren schnell erreicht werden.

• WIRKUNGEN BEI KURZZEITEXPOSITION

  WIRKUNGEN BEI KURZZEITEXPOSITION:
  Die Substanz reizt die Augen und die Haut.

• LECKAGE

  Verschüttetes Material in Behältern sammeln; falls erforderlich durch Anfeuchten Staubentwicklung verhindern. Reste sorgfältig sammeln. An sicheren Ort bringen. Persönliche Schutzausrüstung: Atemschutzgerät, P2-Filter für schädliche Partikel.

• R-Sätze Betriebsanweisung:

  R36/37/38:Reizt die Augen, die Atmungsorgane und die Haut.

• S-Sätze Betriebsanweisung:

  S26:Bei Berührung mit den Augen sofort gründlich mit Wasser abspülen und Arzt konsultieren.
  S36:DE: Bei der Arbeit geeignete Schutzkleidung tragen.

• Beschreibung

  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.

• Chemische Eigenschaften

  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.

• History

  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.

• Verwenden

  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)).

• Application

  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.

• synthetische

  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.

• Definition

  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-).

• Synthese

  Benzoic acid, phthalic acid and other benzene-carboxylic acids in the form of alkali-metal salts, comprise the chargestock. In a first step, the alkali-metal salts (usually potassium) are converted to terephthalates when heated to a temperature exceeding 350 °C (662 °F). The dried potassium salts (of benzoic acid or o- or isophthalic acid) are heated in anhydrous form to approximately 420 °C (788 °F) in an inert atmosphere (CO2) and in the presence of a catalyst (usually cadmium benzoate, phthalate, oxide, or carbonate). The corresponding zinc compounds also have been used as catalysts. In a following step, the reaction products are dissolved in H2O and the terephthalic acid precipitated out with dilute H2SO4. The yield of terephthalic acid ranges from 95 to 98%.

• Application

  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.

• Vorbereitung Methode

  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.

• Synthesis Reference(s)

  Chemistry Letters, 15, p. 299, 1986
  Journal of the American Chemical Society, 82, p. 2876, 1960 DOI: 10.1021/ja01496a051
  The Journal of Organic Chemistry, 44, p. 4727, 1979 DOI: 10.1021/jo00393a063

• Allgemeine Beschreibung

  White powder.

• Air & Water Reaktionen

  Insoluble in water.

• Reaktivität anzeigen

  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.

• Brandgefahr

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

• Flammability and Explosibility

  Non flammable

• Sicherheitsprofil

  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.

• mögliche Exposition

  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.

• läuterung methode

  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.]

• Inkompatibilitäten

  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.

• Waste disposal

  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.

Terephthalic acid Upstream-Materialien And Downstream Produkte

Terephthalsure Anbieter Lieferant Produzent Hersteller Vertrieb Händler.

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