Trimellitic acid
- Trimellitic
- 1,2,4- Tricarboxybenzol
- 1,2,4- benzene tricarboxylic acid
- 1,2,4- Tricarboxybenzen
- 4- Carboxyphthalsäure
White crystals
Fixed
229-231 ° C
Soluble in ethanol and DMF, poor in water, insoluble in nonpolar solvents
Attention
- 2500 mg · kg -1 ( LD50, mouse, oral)
- 6280 mg · kg -1 ( LD50, rat, oral)
Template: Infobox chemical / molecular formula search available
Trimellitic acid, and trimellitic acid in addition to the hemimellitic (1,2,3 -benzenetricarboxylic acid ) and trimesic acid of (1,3,5- benzenetricarboxylic acid ) is one of three possible positional isomers of benzene tricarboxylic acids, and important basic material for the synthesis of paint resins, plasticizers, polyesters, addition to epoxy resins, dyes, etc.
Application and properties
Has trimellitic itself as a commodity commercially less important than the light from it to be formed 1,2- anhydride ( trimellitic anhydride, TMA), which is usually used in its place. Typically, the acid groups are esterified. The standing in the 1,2-position acid groups or the corresponding anhydride are also used for imide formation. The three carboxyl groups are also capable of complex formation with metals. In addition to the many ways it can be mentioned as a special use in the production of extremely heat-resistant polymers such as polyester imides and polyamide-imides.
In the manufacture of plasticizers, as well as the plastic additive with the polymer from the remaining parts of trimellitic acid are trimellitic acid or trimellitic anhydride is important, especially in food contact applications. The limits for migration of both connection are 5 mg · kg -1. When dealing with trimellitic anhydride and caution is advised, particularly the anhydride is highly corrosive to eyes and mucous membranes.
The CD50 - value is 3157 g · kg -1.
Production
As a starting material in the petrochemical industry, the resulting pseudocumene (1,2,4- trimethylbenzene ) is converted by catalytic oxidation of the methyl groups in trimellitic acid. There are various methods by oxidation with chromic acid as well as air oxidation in the presence of metal catalysts. Older methods for producing describe the oxidation of rosin with nitric acid. The prior art is found in the patent literature.