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    Improvements in the separation and recovery of dimethyl terephthalate from vapour mixtures containing the same and methanol
    4.
    发明专利
    Improvements in the separation and recovery of dimethyl terephthalate from vapour mixtures containing the same and methanol 未知

    公开(公告)号：GB882151A

    公开(公告)日：1961-11-15

    申请号：GB219460

    申请日：1960-01-21

    Applicant: BASF AG

    Inventor： SINN RICHARD ,  WASCHKA OTTO ,  KREYER ADOLF

    IPC: C07C69/82

    Abstract: Dimethyl terephthalate is recovered from a vapour mixture consisting mainly of dimethyl terephthalate and methanol by leading the mixture at a temperature between 150 DEG and 350 DEG C. into methanol boiling under reflux, which serves as a cooling medium, and withdrawing a suspension of dimethyl terephthalate in methanol from the system at a rate corresponding to the amount of methanol and ester introduced with the vapour mixture; the dimethyl terephthalate is then separated from the suspension in known manner, e.g. by filtration, centrifuging or decantation, if desired after the suspension has been cooled to between 40 DEG and -10 DEG C. The vapour mixture to be treated preferably contains at least 0,1 part by weight of dimethyl terephthalate per part of methanol and may be a mixture obtained by distilling crude dimethyl terephthalate by carrier-vapour distillation, methanol vapour being used as the carrier. The crude dimethyl terephthate may itself have been obtained from p-xylene by oxidation with nitric acid and the impurities in the vapour mixture may comprise methyl toluate, esters of nitrobenzoic acid, dimethyl nitroterephthate and monomethyl terephthalate. Specification 770,797 is referred to.ALSO:Dimethyl terephthalate is recovered from a vapour mixture consisting mainly of dimethyl terephthalate and methanol by leading the mixture at a temperature between 150 DEG C. and 350 DEG C. into methanol boiling under reflux, which serves as a cooling medium, and withdrawing a suspension of dimethyl terephthalate in methanol from the system at a rate corresponding to the amount of methanol and ester introduced with the vapour mixture; the dimethyl terephthalate is then separated from the suspension in known manner, e.g. by filtration, centrifuging or decantation, if desired after the suspension has been cooled to between 40 DEG C. and - 10 DEG C. The vapour mixture to be treated preferably contains at least 0.1 part by weight of dimethyl terephthalate per part of methanol and may be a mixture obtained by distilling crude dimethyl terephthalate by carrier-vapour distilling, methanol vapour being used as the carrier. The crude dimethyl terephthalate may itself have been obtained from p-xylene by oxidation with nitric acid and the impurities in the vapour mixture may comprise methyl toluate, esters of nitrobenzoic acid, dimethyl nitroterephthalate and monomethyl terephthalate. Specification 770,797 is referred to.

    Continuous process for the oxidation of organic compounds
    7.
    发明专利
    Continuous process for the oxidation of organic compounds 未知

    公开(公告)号：GB918969A

    公开(公告)日：1963-02-20

    申请号：GB130561

    申请日：1961-01-12

    Applicant: BASF AG

    Inventor： BARTHOLOME ERNST ,  NIENBURG HANS ,  SINN RICHARD ,  SCHERF KARL ,  KREYER ADOLF

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

    Abstract: Cyclic mononuclear compounds of aromatic nature, which contain oxidisable side chains, are oxidised to the corresponding carboxylic acids with nitric acid at elevated temperature and increased pressure, if desired in the presence of a catalyst or an oxygen-containing gas, in a vertical reactor through which the reactants flow upwarly. The process is characterized in that the compound to be oxidised, the nitric acid, and the diluent water for the nitric acid, if any, are premixed in a mixer at a temperature below the reaction temperature, and if desired emulsified, and the mixture is led into the bottom of the reactor at such a high speed that it does not separate before entering the reactor, and the flow speed is decreased upon entry to at least one third. The reaction product is withdrawn from the top of the reactor. By decreasing the speed of flow, a vortex is formed and the entering jet sucks hot reaction product to the point of entry of the premixed initial material. The process is carried out at 150-400 DEG C. and at 10-150 atmospheres pressure. The catalyst, if present, may be mercury nitrate, or a nitrate of chromium, iron, or nickel, or an oxide of vanadium, molybdenum, or tungsten, or ammonium vanadate. Nitric acid of 10-40% is preferably used for the oxidation. The compounds of aromatic nature to be oxidised may contain one or more oxidisable side-chain substituents and these may be alkyl groups, or partially oxidised groups containing hydroxy, aldehyde or ketonic groups. Halogen may be present in the side chains. The process may be applied to the oxidation of benzene derivatives, or heterocyclic compounds such as pyridine and thiophene derivatives. Many such compounds are specified representative of which are:- ethyl benzene, butyl benzenes, trimethyl benzenes, ethyl toluenes, trimethylethyl benzenes, dimethyl-sec. butyl benzenes, benzyl alcohol, benzaldehyde, toluyl carboxylic acids, acetophenone, xylylene chloride, nitrotoluenes, chlorotoluenes, bromotoluenes, nitroxylenes, a -, b -, and g -picolines, lutidines, collidines, and a -, and b -methyl thiophene. The temperature of the pre-mixing should be such that no reaction takes place and it should be at least 20 DEG C. below the reaction temperature. The mixed reactants are supplied to the reactor while maintaining turbulence. If desired, the temperature of the reaction zone may be regulated by blowing superheated steam into the reactor at the point of entry of the reaction mixture. The mixing apparatus may comprise a system of successive jet mixers or perforated screens. To facilitate the reaction of slowly reacting compounds, the reactor may be provided with a circulation tube. Examples describe the oxidation of p-di-isopropyl benzene and p-xylene to terephthalic acid; crude xylene to a mixture of phthalic acids; p-nitrotoluene to p-nitro-benzoic acid; g -picoline to isonicotinic acid; pseudo-cumene to trimellitic acid; durene to pyromellitic acid. Specifications 698,157, 793,192 and 820,308 are referred to.

    Purification of terephthalic acid
    8.
    发明专利
    Purification of terephthalic acid 未知

    公开(公告)号：GB906218A

    公开(公告)日：1962-09-19

    申请号：GB304461

    申请日：1961-01-26

    Applicant: BASF AG

    Inventor： MOELL HANS ,  KREYER ADOLF ,  SOENKSEN HANS

    Abstract: Terephthalic acid purified by recrystallisation from an organic solvent by dissolving the acid at 50-250 DEG C., cooling the solution and separating the precipitated acid, the solvent being a lactone containing 5-9 ring atoms, a nitrogen free cyclic ether containing 5-6 ring atoms or a nitrogen free substituted derivative thereof or a mixture of water and at least one of the aforementioned solvents. The purification is applicable to an acid obtained by any method, particularly to acid obtained by nitric acid or air oxidation of disubstituted benzenes. Solvents p mentioned are butyric, valeric, caproic and caprylic lactones and furans, pyrans, dioxans and their alkoxy, hydroxy and methyl substituted derivatives. The preferred solvents are the aqueous mixtures containing approximately equimolar proportions. The crude acid is preferably dissolved in about 15-40 parts by weight of solvent by heating to reflux, the hot solution treated with activated carbon and the purified acid precipitated, if necessary after concentration and addition of numeral acids. Examples are given.

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