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    CONTINUOUS MANUFACTURE OF PHTHALIMIDE
    31.
    发明专利
    CONTINUOUS MANUFACTURE OF PHTHALIMIDE 未知

    公开(公告)号：CA1031351A

    公开(公告)日：1978-05-16

    申请号：CA204414

    申请日：1974-07-09

    Applicant: BASF AG

    Inventor： HETZEL ECKHARD ,  VOGEL LUDWIG ,  ROTERMUND GERHARD ,  HORN HANS C

    IPC: C07D209/48 ,  D07B7/06

    Abstract: 1465756 Phthalamide BASF AG 9 July 1974 [10 July 1973] 30292/74 Heading C2C A continuous process for the preparation of phthalimide comprises reacting phthalic anhydride with ammonia at elevated temperature, washing the off-gas with a melt which contains at least 70% by weight of phthalimide, at a temperature of not less than 210‹ C., and feeding the melt to the reaction. Preferably the reaction is carried out in countercurrent and the wash column is combined with the reactor by using a tray column, the phthalic anhydride melt being fed continuously to one of the middle trays, the ammonia being introduced at the bottom of the column, and the phthalimide melt, as the wash fluid, being introduced at the top of the column.

    Vaporizing urea for production of melamine
    34.
    发明专利
    Vaporizing urea for production of melamine 未知

    公开(公告)号：GB1092662A

    公开(公告)日：1967-11-29

    申请号：GB1286365

    申请日：1965-03-26

    Applicant: BASF AG

    Inventor： HAMPRECHT GUENTHER ,  VOGEL LUDWIG ,  SCHWARZMANN MATTHIAS ,  MOHR RUDOLPH

    IPC: C01C3/14 ,  C07D251/60 ,  F26B3/00

    Abstract: Melamine is prepared by the thermal cracking of urea at 350 DEG to 550 DEG C. in a first stage and subsequent reaction of the cracked gas at 330 DEG to 450 DEG C. in the presence of a catalyst in a second stage, in which the urea starting material is vaporized in the first stage from a finely divided form by direct heat exchange with cracked gas from the first stage or off-gas from the second stage which has been freed from melamine and both of which have been heated up to a temperature of 350 DEG to 550 DEG C.

    Separation of aromatic or pyridine dicarboxylic acids
    38.
    发明专利
    Separation of aromatic or pyridine dicarboxylic acids 未知

    公开(公告)号：GB979280A

    公开(公告)日：1965-01-01

    申请号：GB2822062

    申请日：1962-07-23

    Applicant: BASF AG

    Inventor： SCHENK WALTER ,  VOGEL LUDWIG ,  WALLIS ALBRECHT

    IPC: C07C51/41 ,  C07C51/42 ,  C07C51/43 ,  C07D213/78

    Abstract: Aromatic or pyridine dicarboxylic acids which have two carboxylic groups in the least hindered position and have been obtained by the thermal rearrangement or disproportionation of other carboxylic acids and/or salts, are separated by dissolving the reaction mixture in water or a mixture thereof with low molecular weight water-soluble alcohols or ethers, heating the solution to 80-250 DEG C., acidifying by adding an aromatic monocarboxylic acid or an acid thallium or alkali metal salt (of higher acidity than the corresponding salt of the dicarboxylic acid to be separated) of an aromatic or pyridine dicarboxylic acid, an aromatic polycarboxylic acid, a pyridine carboxylic acid or mixtures thereof to pH 4.1-6.5, the acid salt of the dicarboxylic acid to be separated being completely formed, cooling to 20-30 DEG C., separating the solids and mixing with water to form a slurry which is heated at 105-250 DEG C. at up to 5 atmospheres; acidifying to pH 2.1-4.5 and so that the desired dicarboxylic acid is formed using an aromatic monocarboxylic acid, an aromatic or pyridine di- or poly-carboxylic acid or mixtures thereof or an anhydride of said dicarboxylic acid; cooling to 100-115 DEG C. and separating the crystallized solids. Examples describe the separation of terephthalic acid and pyridine-2, 5-dicarboxylic acid. Naphthalene-2,6-dicarboxylic acid and 4,41-diphenyl dicarboxylic acid are also mentioned. Specification 816,691 is referred to.

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