中科微点-全球专利检索

  1. Login
  2. Sign Up

Search Results

5 records (took 0.02 seconds)

    Improvements in the production of terephthalic acid
    1.
    发明专利
    Improvements in the production of terephthalic acid 未知

    公开(公告)号：GB890387A

    公开(公告)日：1962-02-28

    申请号：GB2798959

    申请日：1959-08-17

    Applicant: BASF AG

    Inventor： SPEER WALTER ,  SCHERF KARL

    IPC: C07C51/265 ,  C07C67/39

    Abstract: Terephthalic acid is prepared by oxidising p-xylene with a gas containing molecular oxygen at elevated temperature in the presence of an oxidation catalyst and in the presence of at least 5% by weight of dimethyl terephthalate with reference to the weight of the mixture to be oxidised and at a temperature above the melting point of the diester. The reaction is preferably carried out by passing oxygen through the mixture at 140 DEG C.-200 DEG C. using about 20%-50% of the diester which is said to act as an oxidation promoter and to bring about oxidation to terephthalic acid in one step. The starting material may be pure p-xylene, commercial crude xylene or xylene mixed with partial oxidation products, e.g. tolualdehyde, toluic acid, terephthalaldehydic acid or esters of the acids with alkanols of 1 to 4 carbon atoms. The catalyst may be a copper, cobalt, manganese or cerium salt of a higher aliphatic acid or hydrobromic acid and may be dissolved in the xylene. A lower alkanol, particularly methanol, may be introduced into the oxidation zone during the oxidation in amounts of 0.5% to 5% by weight based on the mixture to be oxidised. The oxidation may be carried out batchwise or continuously at normal or elevated pressures. The product, which may contain some p-toluic acid may be esterified with methanol under increased pressure in a known manner. Examples are given. Specification 623,826 is referred to.

    Process for the production of benzene carboxylic acids
    3.
    发明专利
    Process for the production of benzene carboxylic acids 未知

    公开(公告)号：GB897801A

    公开(公告)日：1962-05-30

    申请号：GB3325660

    申请日：1960-09-28

    Applicant: BASF AG

    Inventor： HAHL EDGAR ,  BECKE FRIEDRICH ,  SPEER WALTER

    IPC: C07C51/265

    Abstract: Benzene carboxylic acids, anhydrides or mixtures thereof are prepared by liquid phase oxidation, with molecular oxygen at an elevated temperature in presence of an oxidation catalyst and gamma-butyrolactone as solvent, of benzene derivatives, optionally nuclear-substituted by chlorine or carboxyl, which contain 1-3 C1-3 side chains selected from alkyl monochloralkyl, dichloroalkyl and hydroxyalkyl groups. In examples, benzoic acid is obtained from toluene or benzyl alcohol, terephthalic acid from p-xylene, p-cymene or p-toluic acid, isophthalic acid from m-xylene, p-chlorobenzoic acid from p-chlorotoluene and phthalic anhydride from o-xylene, using promoters selected from Co 2-ethylhexanoate + NH4Br or isobutyraldehyde, Cr (III) nitrate + Co (II) phosphate, and NH4VO3 + NaBr. Other specified starting materials are: trimethylbenzene, cumene, diisopropyl benzene, chloromethylbenzene xylyl chloride and xylylidene and xylylene dichlorides. Specifications 737,439, 762,849 and 798,342, also U.S.A. Specification 2,245,528 and German Specification 767,366 are referred to.

Patent Agency Ranking