379711-34-9

Upstream product

• 1459-93-4 dimethyl Isophthalate 
• 121-91-5 isophthalic acid 

Relevant academic research and scientific papers

Process for the preparation of bromoisophthalic acid compounds

The present invention relates to a process for preparing bromoisophthalic acid compounds, particularly 5-bromoisophthalic acid compounds and 4,5-dibromoisophthalic acid compounds comprising brominating an isophthalic acid compound of the general formula (1) wherein R1 and R2 independently of one another are hydrogen atom or C1-6 alkyl, with bromine in a solvent containing sulfur trioxide. The object of the invention is to provide a process for preparing bromoisophthalic acid compounds, particularly 5-bromoisophthalic acid compounds and 4,5-dibromoisophthalic acid compounds in a highly selective manner by using bromine that is industrially inexpensive.

A new route for the preparation of 5-hydroxyisophthalic acid

A new, simple and practical, two-stage process for the preparation of 5-hydroxyisophthalic acid (5-HIPA) from isophthalic acid is described. In the first stage, isophthalic acid is brominated by bromine in oleum, in the presence of an iodine catalyst, to give crude 5-bromoisophthalic acid (5-BIPA). In the second stage the crude 5-BIPA is hydrolyzed with aqueous NaOH, in the presence of a copper catalyst, to give crude 5-HIPA, with a purity of ca. 98%. Both stages of the process were optimized. A single crystallization of the crude 5-HIPA from water gives the product in a purity of more than 99%. The overall yield of pure 5-HIPA is 65-70%.