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    22.
    发明专利
    未知

    公开(公告)号：AT259793T

    公开(公告)日：2004-03-15

    申请号：AT01976093

    申请日：2001-08-16

    Applicant: BASF AG

    Inventor： ISAK HEINZ ,  SENDHOFF NORBERT ,  SCHUETZ FRANZ ,  THERRE JOERG ,  DROEGEMUELLER MICHAEL ,  FRANKE DIRK ,  MUNZINGER MANFRED ,  WECK ALEXANDER ,  BURKART KIRSTEN

    IPC: A01N25/12 ,  A01N43/88 ,  C07D285/34

    Abstract: Described is a process for the preparation of a particulate tetrahydro-3,5-dimethyl-1,3,5-thiadiazine-2-thione product by combining a first aqueous solution comprising methylammonium N-methyldithiocarbamate with a second aqueous solution comprising formaldehyde, followed by separation and drying of the resulting solid, which comprises combining the first and the second aqueous solutions in such a way that the ratio between the concentrations of dithiocarbamate functions and of formaldehyde is essentially constant in the reaction mixture over time during the duration of the reaction.

    23.
    发明专利
    未知

    公开(公告)号：DE19846056A1

    公开(公告)日：2000-04-13

    申请号：DE19846056

    申请日：1998-10-07

    Applicant: BASF AG

    Inventor： THERRE JOERG ,  KAIBEL GERD ,  AQUILA WERNER ,  WEGNER GUENTER ,  FUCHS HARTWIG

    IPC: B01J27/16 ,  C07B61/00 ,  C07C41/28 ,  C07C43/15 ,  C07C45/37 ,  C07C45/51 ,  C07C45/54 ,  C07C45/67 ,  C07C47/21 ,  C07C49/203 ,  C07C45/82

    Abstract: Preparation of citral (I) comprises thermal decomposition of 3-methyl-2-buten-1-al-diprenylacetal and rearrangement of obtained intermediates cis/trans-prenyl-(methyl-butadienyl)-ether (IV) and 2,4,4-trimethyl-3-formyl-1,5-hexadiene (V). (IV) and (V) are continuously distilled off and converted into (I) before or after removal of by-product prenol. Preparation of 3,7-dimethyl-2,6-octadien-1-al (citral) of formula (I) comprises: (1) thermal decomposition of 3-methyl-2-buten-1-al-diprenylacetal of formula (II) optionally in the presence of an acid catalyst to split off 3-methyl-buten-1-ol (prenol) of formula (III) and form cis/trans-prenyl-(methyl-butadienyl)-ether of formula (IV); (2) Claisen rearrangement of (IV) to give 2,4,4-trimethyl-3-formyl-1,5-hexadiene of formula (V); and (3) Cope rearrangement of (V) to form (I). The transitionally formed (IV) and (V) and the desired citral as well as the prenol (III) are continuously distilled out of the reaction mixture and (IV) and (V), before or after distillative separation of (III) and optional by-products, are subjected to rearrangement to form (I) at 100-200 degrees C.

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