4-Chlorocarbonyl-2-sulphobenzoic acid anhydrides - esp. useful as polyamide inters., prepd. from trisodium sulpho-terephthalates

摘要

4-Chlorocarbonyl-2-sulphobenzoic acid anhydrides of formula (I) are new (where R1, R2 and R3 are lower alkyl and/or halogen, alkoxy or CF3, or pref. H). Cpds. (I) can be used as inter. for plastics, dyes, plant protection agents and pharmaceuticals, and are esp. useful for the prepn. of sulphonate-modified aromatic polyamides. Cpds. (I) can be prepd. by reacting the trisodium salt of the corresp. sulphoterephthalic acid with 4-20 pts. wt. of SOCl2 at 60-90 degrees C for 3-6 hr.