Ortho Fused Rings In Acid Moiety Patents (Class 560/80)
  • Method of purifying crude 2,6-naphthalenedicarboxylic acid dimethyl ester
    Patent number: 4048021
    Abstract: In a method of obtaining purified 2,6-naphthalenedicarboxylic acid dimethyl ester by vacuum distilling crude 2,6-naphthalenedicarboxylic acid dimethyl ester under conditions of application of heat, the improvement which comprises vacuum distilling a crude 2,6-naphthalenedicarboxylic acid dimethyl ester having an acid value (A.sub.f), as expressed in milligrams of KOH required for neutralizing the carboxyl groups contained in one gram of said crude 2,6-naphthalenedicarboxylic acid dimethyl ester, of from 1.0 to 50.
    Type: Grant
    Filed: September 23, 1976
    Date of Patent: September 13, 1977
    Assignee: Teijin Limited
    Inventors: Hiromitsu Takamoto, Kiyoshi Yamamoto, Nobuo Taneda, Toru Matsubayashi, Gentaro Yamashita