摘要:
Process for the preparation of 2-substituted 4-hydroxy-4-methyltetrahydropyrans of the formula (I) where the radical R1 is a straight-chain or branched alkyl or alkenyl radical having 1 to 12 carbon atoms, an optionally alkyl-substituted cycloalkyl radical having in total 3 to 12 carbon atoms or an optionally alkyl- and/or alkoxy-substituted aryl radical having in total 6 to 12 carbon atoms, comprising the reaction of 3-methylbut-3-en-1-ol of the formula (II) with an aldehyde of the formula (III) R1—CHO (III), where the radical R1 has the same meaning as in formula (I) and where the reaction is carried out in the presence of water and in the presence of a strongly acidic cation exchanger, and then the isolation and/or the distillative separation is carried out in a dividing wall column or in an interconnection of (at least) two distillation columns in the form of a thermal coupling and one or more side take-off points at an absolute operating pressure of up to 500 mbar.
摘要:
Process for the preparation of 2-substituted 4-hydroxy-4-methyltetrahydropyrans of the formula (I) where the radical R1 is a straight-chain or branched alkyl or alkenyl radical having 1 to 12 carbon atoms, an optionally alkyl-substituted cycloalkyl radical having in total 3 to 12 carbon atoms or an optionally alkyl- and/or alkoxy-substituted aryl radical having in total 6 to 12 carbon atoms, comprising the reaction of 3-methylbut-3-en-1-ol of the formula (II) with an aldehyde of the formula (III) R1—CHO (III), where the radical R1 has the same meaning as in formula (I) and where the reaction is carried out in the presence of water and in the presence of a strongly acidic cation exchanger, and then the isolation and/or the distillative separation is carried out in a dividing wall column or in an interconnection of (at least) two distillation columns in the form of a thermal coupling and one or more side take-off points at an absolute operating pressure of up to 500 mbar.
摘要:
A process for the isolation of amines from aqueous solutions by continuous distillation of aqueous solutions of the amines by a two-pressure method of rectifying aqueous solutions of amines which form with water an azeotrop, the composition of which is pressure-dependent, in two columns at different pressures provided that: a) the pressure in the second column is set to a value at least 0.5 bar higher than in the first column, b) the aqueous amine solution is fed, as a side stream, to the first column, and water and portions which boil at a higher temperature than the amine or which are non-volatile are removed at the base of the column, c) a mixture of amine and water is withdrawn at the head of the first column and fed, as a side stream, to the second column, d) an azeotrope of water and amine is withdrawn at the head of the second column and recycled to the first column, and (e) the purified amine is discharged at the base of the second column.
摘要:
The invention relates to a process for the preparation of m- or p-substituted phenylalkanols of the formula (I) in which R1 is bonded to the phenyl ring in the m- or p-position and is C1-C5-alkyl, and R2, R3, R4 and R5, independently of one another, are hydrogen or methyl, wherein an unsubstituted phenylalkanol of the formula (II) in which R2, R3, R4 and R5 have the meanings given under formula (I) is alkylated together with a C1-C5-alkyl halide of the formula (III) R1-Hal (III), in which R1 has the meaning given under formula (I) and Hal is halogen, in the presence of a Friedel-Crafts catalyst to give an m- or p-alkyl-substituted phenylalkanol of the formula (I), then the reaction mixture is worked-up and the desired m- or p-alkyl-substituted phenylalkanol of the formula (I) is separated off, the other formed by-products are returned to the reaction mixture and these are isomerized in the presence of a Friedel-Crafts catalyst to give the desired m- or p-alkyl-substituted phenylalkanol. From the m- or p-alkyl-substituted phenylalkanols of the formula (I), it is possible to form, by oxidation or dehydrogenation, as products of value, the corresponding aldehydes, which play an interesting role as fragrances and aroma chemicals.
摘要:
The present invention relates to a fragrance composition comprising a mixture of diastereomers of 2-isobutyl-4-methyl-tetrahydro-2H-pyran-4-ol, which comprises more than 95 wt. % of the optically inactive cis-racemate and less than 5 wt. % of the optically inactive trans-racemate. The present invention further relates to a method for producing a perfumed product or article as well as perfumed or aromatized articles comprising the fragrance compositions of the present invention.
摘要:
A process for preparing 2-cyano-3,3-diarylacrylic esters of the general formula I ##STR1## where R.sup.1 and R.sup.2 are hydrogen, C.sub.1 -C.sub.12 -alkyl groups, C.sub.- C.sub.12 -alkoxy groups or di(C.sub.1 -C.sub.4 -alkyl)amino groups and R.sup.3 is a C.sub.4 -C.sub.18 -alkyl group which can be interrupted by ether-functional oxygen atoms, by reacting a benzophenone imine of the general formula II ##STR2## with a cyanoacetic ester of the general formula III ##STR3## wherein the reaction is carried out at from 20 to 60.degree. C. and, during this, the liberated ammonia is continuously removed from the reaction mixture with the aid of a stream of gas or by reducing the pressure to from 900 to 100 mbar.
摘要:
A process for removing water and ammonia from benzophenone imine reactor effluents resulting from the catalytic reaction of benzophenones of the formula I ##STR1## where R.sup.1 and R.sup.2, have the meaning stated in the specification and wherein ammonia is distilled off from effluents and wherein water is either distilled off from the effluents over removed non-distillatively.
摘要:
The invention relates to a process for the preparation of m-substituted phenylalkanols of the formula (I) in which R1 is C1-C5-alkyl and R2, R3, R4 and R5, independently of one another, are hydrogen or methyl, wherein a p-substituted phenylalkanol of the formula (II) in which R1, R2, R3, R4 and R5 having the meanings given under formula (I), is isomerized in the presence of a Friedel-Crafts catalyst to give an m-substituted phenylalkanol of the formula (I). From the m-substituted phenylalkanols of the formula (I) it is possible to form, by oxidation or dehydrogenation, as products of value, the corresponding aldehydes, which are known as fragrances and aroma chemicals.
摘要:
The present invention relates to a method of producing pure or enriched bisabolol by separating substance mixtures comprising bisabolol and farnesol by selective esterification of farnesol and subsequent distillative separation. The invention relates specifically to a method as specified above comprising the selective transesterification of mixtures comprising formyl-bisabolol and formyl-farnesol and subsequent distillative separation.The present invention furthermore relates to a method of producing farnesol esters.
摘要:
This invention relates to a process of producing compounds, which are useful as bleach boosters, as well as to the compounds, which are obtainable using said process, and to their use.