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    23.
    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
    24.
    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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