Trimellitic acid
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| General | ||||||||||||||||
| Surname | Trimellitic acid | |||||||||||||||
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| Molecular formula | C 9 H 6 O 6 | |||||||||||||||
| Brief description |
white crystals |
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| properties | ||||||||||||||||
| Molar mass | 210.14 g mol −1 | |||||||||||||||
| Physical state |
firmly |
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| Melting point |
229-231 ° C |
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| solubility |
soluble in ethanol and DMF , poor in water, insoluble in non-polar solvents |
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| As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . | ||||||||||||||||
Trimellitic acid , and trimellitic acid in addition to the hemimellitic (1,2,3-benzenetricarboxylic acid) and trimesic acid (1,3,5-benzenetricarboxylic acid) is one of three possible positional isomers of benzene tricarboxylic acids , and important basic material for the synthesis of resins for coatings, plasticizers , polyesters , addition to Epoxy resins , dyes , etc.
Application and properties
Trimellitic acid itself is less important as a raw material in trade than the 1,2-anhydride ( trimellitic anhydride , TMA) which is easily formed from it and which is usually used in its place. Typically the acid groups are esterified . The acid groups in the 1,2-position or the corresponding anhydride group are also used to form imides . The three carboxylic acid groups are also capable of complexing metals. In addition to the wide range of possible uses, a special feature is the use for the production of extremely heat-resistant polymers such as polyesterimides and polyamideimides .
Residual components of trimellitic acid or trimellitic anhydride are important in the production of plasticizers as plastic additives, but also in the case of polymers made from trimellitic acid, especially when they come into contact with food. The limit values for migration of both compounds are 5 mg kg −1 . Care should be taken when handling trimellitic acid and its anhydride, the anhydride in particular is extremely corrosive to the eyes and mucous membranes .
The CD50 value is 3157 g kg −1 .
Manufacturing
As a starting material, the pseudocumene (1,2,4-trimethylbenzene) obtained in the petrochemical industry is converted into trimellitic acid by catalytic oxidation of the methyl groups. There are various processes with oxidation by chromosulfuric acid as well as air oxidation in the presence of metal catalysts. Older methods of production describe the oxidation of rosin with nitric acid . The prior art can be found in the patent literature.
Individual evidence
- ↑ a b c ChemYQ database
- ↑ a b c data sheet 1,2,4-Benzenetricarboxylic acid from Sigma-Aldrich , accessed on April 24, 2011 ( PDF ).
- ↑ Entry on trimellitic acid in the ChemIDplus database of the United States National Library of Medicine (NLM) .
- ↑ a b Batyrova TF, Uzhdavini ER: The Toxicology of Trimellitic Acid and Trimellitic Anhydride ; Trudy Nauchno-Issledovatel'skii Institut Neftekhimicheskikh Proizvodstr, No. 2, pp. 149-154, 1970.
- ↑ Official Journal of the European Union: DIRECTIVE 2005/79 / EC OF THE COMMISSION of November 18, 2005 amending Directive 2002/72 / EEC on plastic materials and articles intended to come into contact with food (PDF) .
- ↑ Plastic Ordinance Austria ( Memento of April 7, 2014 in the Internet Archive ) (PDF; 80 kB).
- ↑ Air oxidation of pseudocumene: Patent EP0513835 : Process for the production of trimellitic acid. Registered on May 15, 1992 , published on August 9, 1995 , applicant: Lonza , inventors: Carlo Fumagalli, Lorenzo Capitanio, Giancarlo Stefani.
- ↑ Oxidation of 2,6-diisopropylnaphthalene to trimellitic acid: Patent DE3707876A1 : Process for the production of naphthalenedicarboxylic acid together with trimellitic acid. Applied on March 11, 1987 , published on September 17, 1987 , applicant: Kureha Kagaku Kogyo , inventor: Hayashi, Shoichiro; Matsuda, Toshiharu; Sasawaka, Atsushi.