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    CONTINUOUS PROCESS FOR PREPARING ACETAL
    1.
    发明专利
    CONTINUOUS PROCESS FOR PREPARING ACETAL 审中-公开

    公开(公告)号：JP2002114728A

    公开(公告)日：2002-04-16

    申请号：JP2001272755

    申请日：2001-09-07

    Applicant: BASF AG

    Inventor： THERRE JORG ,  KAIBEL GERD ,  AQUILA WERNER DR ,  WEGNER GUNTER ,  FUCHS HARTWIG

    IPC: C07C41/50 ,  C07B61/00 ,  C07C41/56 ,  C07C41/58 ,  C07C43/303

    Abstract: PROBLEM TO BE SOLVED: To overcome disadvantages of the prior art and to provide a process for preparing an unsaturated acetal which is easy to regulate and can be operated in a stable manner. SOLUTION: This continuous process for preparing the unsaturated acetal of formula I (wherein, R1 to R7 are each independently hydrogen or a straight- chain or a branched, optionally substituted 1-6C alkyl group; R8 is hydrogen or a saturated or a mono- or a polyunsaturated straight-chain or branched, optionally substituted 1-12C alkyl group or a 3- to a 12-membered saturated or a mono- or a polyunsaturated carbocyclic ring) by reacting 1 mol of an aldehyde of formula II (wherein, R1 to R3 are as defined in the following formula I) with at least 1 mol of an alcohol of formula III (wherein, R5 to R8 are as defined by the following formula I) in the presence of a catalytic amount of an acid while removing water formed during the reaction, which comprises only partially reacting the reactants in a reactional column, concentrating the resultant acetal in at least two successive evaporation stages and returning the recovered reactants to the reactional column.

    6.
    发明专利
    未知

    公开(公告)号：PT992477E

    公开(公告)日：2003-06-30

    申请号：PT99118458

    申请日：1999-09-17

    Applicant: BASF AG

    Inventor： THERRE JORG ,  KAIBEL GERD ,  AQUILA WERNER ,  FUCHS HARTWIG ,  WEGNER GUNTER

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

    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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