摘要:
Disclosed is a process for purification of p-hydroxymethylbenzoic acid containing 4-carboxybenzaldehyde, p-toluic acid and terephthalic acid impurities.
摘要:
This invention relates to dicyclohexadiene tetraacyl compounds. More particularly, this invention relates to dicyclohexadiene dianhydrides, dicyclohexadiene tetracarboxylic acid esters and dicyclohexadiene tetracarboxylic acids.
摘要:
Disclosed is a process for the preparation of poly(p-methylenebenzoate) from p-hydroxymethylbenzoic acid containing no more than about 10% by weight terephthalic acid and no more than about 0.3 (wt) % total of 4-carboxybenzaldehyde and p-toluic acid.
摘要:
Highly-purified monomers for poly(p-methylenebenzoate) polymers and poly(m-methylenebenzoate) polymers are prepared by purifying acetoxylated hydroxymethylbenzoic acid compounds derived by side-chain acetoxylation of toluic acid compounds. The purification process can be by recrystallation or by fractional distillation.
摘要:
A crude p-hydroxymethylbenzoic acid compound containing 4-carboxybenzaldehyde is purified and decolorized by hydrogenation in the presence of a platinum on carbon catalyst. 4-carboxybenzaldehyde is hydrogenated to p-hydroxymethylbenzoic acid. Toluic acid is not a product of the hydrogenation process.
摘要:
A catalyst, a process for preparing said catalyst, and a process for producing purified terephthalic acid, wherein 4-carboxybenzaldehyde is reduced to very low levels, wherein said catalyst is prepared by contacting a solution of a suitable palladium salt in an organic solvent with a suitable activated carbon support, wherein said palladium salt is reduced to palladium metal crystallites by said activated carbon support. Purified terephthalic acid is prepared by hydrogenating crude terephthalic acid in the presence of said catalyst.
摘要:
This invention is related to the production of trimellitic anhydride (TMA). More specifically, the invention is related to the addition of a mineral acid or salt thereof in the production process of trimellitic anhydride to reduce the viscosity of the bottoms fraction when TMA is purified by distillation and thus to prevent fouling/plugging. This permits the use of lower levels of TMA in the bottoms fraction and increases TMA recovery.
摘要:
A catalyst, a process for preparing said catalyst, and a process for producing purified terephthalic acid, wherein 4-carboxybenzaldehyde is reduced to very low levels, wherein said catalyst is prepared by contacting a solution of a suitable palladium salt in an organic solvent with a suitable activated carbon support, wherein said palladium salt is reduced to palladium metal crystallites by said activated carbon support. Purified terephthalic acid is prepared by hydrogenating crude terephthalic acid in the presence of said catalyst.