| abstract |
Mono- or di-benzoylpyromellitic acids made by reacting benzoyl chloride with tetramethyl- 1,2,4,5-benzene using as catalyst, e.g. AlCl3. For the monobenzoyl compound, 10 moles % excess benzoyl chloride is used, and for the dibenzoyl compound, 4 to 6 moles of benzoyl chloride/mole of tetramethyl benzene. The product is oxidised to the acid by alkalibichromates, etc., and then converted, if desired to the dianhydride by heating. Used as hardeners for epoxy resins and for making polyesters, polyamides and polyimides for use in adhesives. |