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    Process for the purification of crude dimethyl terephthalate
    1.
    发明授权
    Process for the purification of crude dimethyl terephthalate 失效
    纯化粗对苯二甲酸二甲酯的方法

    公开(公告)号：US3073754A

    公开(公告)日：1963-01-15

    申请号：US383360

    申请日：1960-01-21

    Applicant: BASF AG

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

    IPC: B01D9/00 ,  C07C69/82

    CPC classification number: B01D9/0013 ,  B01D9/0059 ,  C07C67/54 ,  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.

    Improvements in the production of terephthalic acid
    3.
    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.

    Improvements in the purification of crude dimethyl terephthalate by distillation
    4.
    发明专利
    Improvements in the purification of crude dimethyl terephthalate by distillation 未知

    公开(公告)号：GB870012A

    公开(公告)日：1961-06-07

    申请号：GB219560

    申请日：1960-01-21

    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.

    8.
    发明专利
    未知

    公开(公告)号：DE1098503B

    公开(公告)日：1961-02-02

    申请号：DEB0051853

    申请日：1959-01-24

    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.

    Continuous oxidation of aromatic compounds with nitric acid
    10.
    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.

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