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    PROCESS FOR THE PREPARATION OF FORMALDEHYDE
    37.
    发明专利
    PROCESS FOR THE PREPARATION OF FORMALDEHYDE 未知

    公开(公告)号：DE3461368D1

    公开(公告)日：1987-01-08

    申请号：DE3461368

    申请日：1984-12-18

    Applicant: BASF AG

    Inventor： AICHER ALBRECHT ,  LEHMANN GUNTER ,  PETRI NORBERT DR ,  PITTEROFF WALTER DR ,  REUSS GUENTER DR ,  SCHREIBER HANS ,  SEBASTIAN ROBERT

    IPC: B01J23/00 ,  B01J23/50 ,  C07B61/00 ,  C07C45/00 ,  C07C45/38 ,  C07C45/78 ,  C07C45/80 ,  C07C45/81 ,  C07C47/04 ,  C07C47/055 ,  C07C67/00

    Abstract: Formaldehyde is prepared by (a) passing a mixture of methanol and water with a concentration of between 50 and 90% by weight, based on the total weight of the two substances, of methanol into a packed column which possesses a packing having a total layer thickness of not less than 50 cm and a total surface area of not less than 0.5 cm2 per cm3 of packing, a liquid circulation of from 15 to 90 g/min per g/min of methanol fed to the column, and a concentration of from 10 to 45% by weight of methanol in the recycle liquid, the temperature at the point of entry of the recycle liquid in the column being from 50 DEG to 86 DEG C. and the bottom temperature being 10 DEG -25 DEG C. lower than this, i.e. from 40 DEG to 70 DEG C., (b) separating off methanol and water from the column by stripping with air, an inert gas and/or exit gas, the throughput being from 0.5 to 3 tonnes of methanol and water per hour per m2 of column cross-section, (c) converting the gaseous mixture of methanol, water, air, inert gas and/or exit gas at a space velocity of from 0.5 to 3 tonnes of methanol per m2 of catalyst bed cross-section per hour, in the presence of a silver catalyst at from 550 DEG to 750 DEG C. and (d) finally, cooling and absorbing the hot reaction gases, and using the resulting heat of absorption and, if desired, the heat of reaction and/or the heat of condensation partially or completely for heating the recycle liquid, methanol containing impurities being used if desired and, after the stages (a) and (b) and before the stages (c) and (d), the measures of a stage (e) being carried out, wherein the gaseous mixture formed is passed through two layers of wire filter having a wire diameter of from 0.1 to 0.5 mm and a free layer volume of from 90 to 99.5 vol. %, based on the total volume of one wire layer, at a flow rate of from 7 to 13 m/sec in the first layer, and from 1 to 4 m/sec in the second layer. The formaldehyde obtainable by the process of the invention is a disinfectant, tanning agent, reducing agent and a useful starting material for the preparation of synthetic resins, adhesives and plastics.

    38.
    发明专利
    未知

    公开(公告)号：NO144208C

    公开(公告)日：1981-08-05

    申请号：NO744213

    申请日：1974-11-22

    Applicant: BASF AG

    Inventor： DIEM HANS ,  LIBOWITZKY HERBERT ,  MATTHIAS GUENTHER ,  DUDECK CHRISTIAN ,  LEHMANN GUNTER

    IPC: C07C45/00 ,  C07C45/86 ,  C07C47/058 ,  C07C67/00

    Abstract: 1480921 Stabilizing aqueous formaldehyde BASF AG 25 Nov 1974 [26 Nov 1973] 50896/74 Heading C2C Aqueous formaldehyde solutions are stabilized by means of a bis-guanamine of formula wherein the two substituent on the phenylene ring are in m or p-position to each other. 0À001 to 0À5% by weight of stabilizer may be used and the formaldehyde solution may contain 28-65% by weight of formaldehyde. The stabilizer may be added as a stock solution in a formaldehyde solution of higher strength than that to be stabilized and having a pH of 2À5 to 5À8 and the latter is preferably kept at 40-80‹ C. for 10-30 hours before adding the stock solution.

    MANUFACTURE OF CONCENTRATED AQUEOUS SOLUTIONS OF FORMALDEHYDE
    39.
    发明专利
    MANUFACTURE OF CONCENTRATED AQUEOUS SOLUTIONS OF FORMALDEHYDE 未知

    公开(公告)号：CA1058221A

    公开(公告)日：1979-07-10

    申请号：CA235507

    申请日：1975-09-11

    Applicant: BASF AG

    Inventor： AICHER ALBRECHT ,  HAAS HANS ,  DIEM HANS ,  DUDECK CHRISTIAN ,  BRUNNMUELLER FRITZ ,  LEHMANN GUNTER

    IPC: C07B61/00 ,  C07C45/00 ,  C07C45/38 ,  C07C45/78 ,  C07C47/055 ,  C07C47/058 ,  C07C67/00 ,  C07C47/04

    Abstract: Concentrated aqueous solutions of formaldehyde are manufactured by the oxidative dehydrogenation of methanol with air in the presence of a silver crystal catalyst bed and of steam, at a temperature from 550 to 780.degree.C, followed by absorption, in water, of the formaldehyde formed. According to the invention, the reaction is carried out with a throughput of from 1 to 3 tonnes of methanol per square meter of catalyst bed cross-section per hour in the presence of from 0.1 to 1.8 moles of water and from 0.04 to 0.4 mole of formaldehyde per mole of total methanol fed to the catalyst, the formaldehyde and from 0.1 to 1.8 moles of water per mole of total methanol fed to the catalyst are taken from the reaction mixture after the reaction and added to the starting mixture, and (a) a part of the formaldehyde and water is abstracted from the formaldehyde solution, formed in the absorption stage, by means of the air fed to the reaction, at from 60 to 90.degree.C, or (b) a part of the formaldehyde solution formed in the absorption stage is vaporized and recycled to the reaction, or (c) simultaneously a part of the formaldehyde and water is abstracted from the formaldehyde solution, formed in the absorption stage, by the air fed to the reaction, at from 60 to 90.degree.C, and a part of the formaldehyde solution formed in the absorption stage is vaporized and recycled to the reaction. The formaldehyde solution obtained by this process may be used as a disinfectant, tanning agent, reducing agent and starting material for the manufacture of synthetic resins, adhesives and plastics.

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