On October 7, 2015, Myung, Beom Yeong; Yoon, Tae Ho published a patent.Application of 41819-13-0 The title of the patent was Method for the preparation of fluorinated pyromellitic dianhydride. And the patent contained the following:
Disclosed is a preparation method of I, characterized by (1) bromination of pyromellitic dianhydride to obtain II (2) successive reaction of Q1-Br with magnesium and trimethylborate followed by hydrolysis to obtain Q1-B(OH)2 (3) treatment of II with Q1-B(OH)2 in the presence of a catalyst (4) sublimation of the resulting compound III under reduced pressure [R1, R2 = independently H or Q1; with a proviso that R1 and R2 cannot be H simultaneously; R3, R4 = independently fluorinated alkyl; A1, A2 = independently H or Br]. For example, bromination of pyromellitic dianhydride [dissolving in 33% aqueous NaOH → Br2 (addition over a period of 1 h), 90%], coupling reaction with 3,5-bis(trifluoromethyl)phenylboronic acid (preparation given) [Pd(PPh3)4, 2 N Na2CO3, toluene, 98°, 48 h, 72%] and cyclocondensation [drying (250°, 30 inHg vacuum pressure, 12 h) → sublimation (290°, 30 inHg vacuum pressure)] afforded compound I [R1 = R2 = 3,5-bis(trifluoromethyl)phenyl] (70% yield). Compound I is useful for the production of polyimide having low permittivity and high heat-resistance. The experimental process involved the reaction of 3,6-Dibromobenzene-1,2,4,5-tetracarboxylic acid(cas: 41819-13-0).Application of 41819-13-0
The Article related to fluoroalkylphenyl pyromellitic dianhydride preparation polyimide intermediate, grignard reaction borylation hydrolysis, bromination coupling reaction cyclocondensation sublimation and other aspects.Application of 41819-13-0
Referemce:
Bromide – Wikipedia,
bromide – Wiktionary