C - Chemistry – Metallurgy – 07 – C
Patent
C - Chemistry, Metallurgy
07
C
C07C 229/62 (2006.01) C07C 227/08 (2006.01) C07C 227/16 (2006.01)
Patent
CA 2071107
HOE 91/F 175 Abstract of the Disclosure Process for the preparation of 2,5-di(phenylamino)- terephthalic acid and its dialkyl esters in high purity A process for the preparation of 2,5- di(phenylamino)terephthalic acid and its dialkyl esters of formula (I): Image (I) in which R is a hydrogen atom or a methyl group and R' is a hydrogen atom or a methyl or ethyl group, by (1) reacting a dialkyl(C1-C2) succinate with a sodium alcoholate in xylene, in the manner of a Dieckmann condensation, to give the disodium salt of the dialkyl (C1-C2)2,5-dihydroxycyclohexadiene-1,4-dicarboxylate, (2) reacting the resulting condensation product, after decomposition of the disodium salt with acid, with a phenylamine of formula (II): Image (II) in which R is as defined above, in the presence of an organic acid, in xylene, to give the dialkyl(C1-C2) 2,5- di(phenylamino)-3,6-dihydroterephthalate, (3) dehydro- genating (oxidizing) the resulting 1,4-cyclohexadiene derivative with oxygen to give the corresponding dialkyl(C1-C2) 2,5-di(phenylamino)terephthalate, (4) saponifying the resulting dialkyl ester in methanolic sodium hydroxide solution to give the corresponding disodium 2,5-di(phenylamino)terephthalate, and (5) liberating the 2,5-di(phenylamino)terephthalic acid from said disodium salt with acid, which process comprises carrying out the oxidation in stage (3) in such a way that the reaction mixture of stage (2), in the form of a solution or suspension, is blanketed with nitrogen in a stirred vessel, this reaction mixture is circulated by pumping and the oxygen is metered into a partial volume of the circulated reaction mixture in such a way as to produce effective thorough mixing.
Arndt Otto
Fuchs Hermann
Gilb Walter
Fetherstonhaugh & Co.
Hoechst Aktiengesellschaft
LandOfFree
Process for the preparation of... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for the preparation of..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for the preparation of... will most certainly appreciate the feedback.
Profile ID: LFCA-PAI-O-1352035