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    Continuous oxidation of aromatic compounds with nitric acid
    28.
    发明专利
    Continuous oxidation of aromatic compounds with nitric acid 未知

    公开(公告)号：GB974068A

    公开(公告)日：1964-11-04

    申请号：GB1589263

    申请日：1963-04-23

    Applicant: BASF AG

    Inventor： BORTHOLOME ERNST ,  NIENBURG HANS ,  SCHENK WALTER ,  SCHERF KARL ,  LOESCH NORBERT ,  WALLIS ALBRECHT ,  VOGEL LUDWIG

    IPC: B01J14/00 ,  B01J19/00 ,  B01J19/24 ,  C07C51/275 ,  C07C205/57 ,  C07D213/79 ,  C07D213/803 ,  C07D215/48 ,  C07D215/50

    Abstract: The parent Specification describes a process in which aromatic mononuclear compounds containing oxidizable side chains are oxidized to the corresponding carboxylic acids with nitric acid at a raised temperature and pressure, the reaction being effected in a vertical reactor through which the reagents flow upwardly and the reagents being mixed, at a temperature below the reaction temperature, before they enter the reactor, the arrangement being such that the speed of the mixture is decreased to at least one third as it enters the reactor. This process is now modified in that only 30-60% of the required nitric acid is supplied to the mixer, the remainder being supplied directly to the reactor at about the middle third. As in the parent Specification, the reaction may be effected at 150-400 DEG C. at 10-150 atm. pressure and optionally in the presence of the catalysts named in the parent Specification. Specified materials which may be oxidized are toluene, xylenes, cymene, diisopropylbenzenes, chlorotoluenes, nitrotoluenes, chloroxylenes, nitroxylenes, mesitylene, durene, toluic acids, benzyl chloride, xylylene dichlororide, chloromethylated xylenes, picolines and ethylpyridines. An example is given of the oxidation of p-xylene to terephthalic acid.

    Recovery of alkali metal salts of benzenecarboxylic acids
    29.
    发明专利
    Recovery of alkali metal salts of benzenecarboxylic acids 未知

    公开(公告)号：GB973589A

    公开(公告)日：1964-10-28

    申请号：GB2821962

    申请日：1962-07-23

    Applicant: BASF AG

    Inventor： SCHENK WALTER ,  WALLIS ALBRECHT ,  VOGEL LUDWIG

    IPC: C07C51/41 ,  C07C51/42 ,  C07C63/20

    Abstract: Dry neutral alkali metal benzenecarboxylates, which may be thermally converted into other alkali metal benzenecarboxylates, are recovered from their aqueous solutions by adjusting the latter to a pH 0.05-0.9 unit above the point of equivalence by addition of alkali metal hydroxide and dividing the solutions thus obtained into two streams, of which one is led into a conventional evaporator and the other is sprayed into a wash tower through which a CO2-containing gas passes in countercurrent. The sodium and potassium salts of benzoic, phthalic and isophthalic acids are specifically mentioned as recoverable salts. Specification 840,040 and U.S.A. Specification 2,930,813 are referred to.

    30.
    发明专利
    未知

    公开(公告)号：FR1245493A

    公开(公告)日：1960-11-04

    申请号：FR816564

    申请日：1960-01-25

    Applicant: BASF AG

    Inventor： AROYAN HARRY JAMES ,  SINN RICHARD ,  SCHERF KARL ,  VOGEL LUDWIG

    IPC: B01D9/00 ,  C07C69/82

    Abstract: Pure dimethyl terephthalate is recovered from mixtures of the ester with methanol, water and other impurities by a process in which a distillation column 1 is maintained at a pressure at which the condensation temperature of the vaporized methanol-water mixture is above the solidification temperature of the ester, i.e. at least 8 atmospheres, an overhead fraction of methanol, water and low-boiling impurities is led off by line 5 to a second, dehydrating, distillation column 10 from which pure methanol is obtained overhead by line 11 and water and impurities are drained off by line 35, the ester mixed with high-boiling impurities is led by line 9 into a third distillation column 14 maintained at atmospheric or slightly elevated pressure up to 1 atmosphere gauge, to which column methanol vapour is also fed by line 13, and the pure ester is separated from methanol after the fraction consisting of ester and methanol distilled off by line 18 is condensed. High-boiling impurities are discharged by line 16. Crude mixtures preferably contain 1.5 to 8 parts of methanol per part of ester and the water content is between 1 and 30% of the methanol content. Two columns instead of column 1 may be used. The vapours in line 18 are condensed at atmospheric or reduced pressure in a vessel 20 and the condensate is cooled further, e.g. to between 40 DEG C. and -10 DEG C., in a container 21 to crystallize the ester, which is then separated from methanol in a centrifuge 24. The ester, after washing, if desired, with methanol from line 26, is passed to a drier 28 while excess methanol is passed to a reservoir 25 for use in the esterification of terephthalic acid or for circulation to the second column 10 by line 33.

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