摘要:
Distillative separation of liquid mixtures of one or more water-insoluble substances which have boiling points higher than that of water and one or more substances which have boiling points lower than that of water or which form azeotropes having boiling points lower than that of water, wherein the mixture to be distilled is mixed with a quantity of water such that the boiling point of the water under the pressure applied limits the bottom temperature of the mixture of substances to be separated.
摘要:
Citral (I) ##STR1## is prepared by heating an acetal (IIa) or (IIb) ##STR2## in the presence of an acid catalyst while continuously distilling from the reaction mixture the 3-methylbut-2-en-1-ol (III, prenol) eliminated during the reaction.
摘要:
An improved process for the preparation of higher unsaturated ketones, such as geranylacetone and farnesylacetone, by reacting a .beta.,.gamma.-unsaturated alcohol and an alkyl acetoacetate at an elevated temperature in the presence of an organic aluminum compound, with elimination, and removal, of the alcohol derived from the alkyl acetoacetate in a reactor system carrying a fractionating column. The improvement in the purity, yield, and especially space-time yield of the product is achieved by starting from an alcohol having a higher boiling point than that of the alkyl acetoacetate used, carrying out the reaction in the presence of a small amount of an inert liquid which has a boiling point between that of the alkyl acetoacetate and the alcohol to be eliminated therefrom, and ensuring that the temperature at the bottom of the fractionating column is only slightly higher than the boiling point of the added liquid, under the prevailing pressure.
摘要:
An improved process for the manufacture of 2-methyl-2-hepten-6-one by reacting an alkyl acetoacetate with 2-methyl-3-buten-2-ol in the presence of an organic aluminum compound such as aluminum trialcoholate, aluminum triacetoacetate, aluminum alkylacetoacetate or aluminum triaryloxylate. 2-Methyl-2-hepten-6-one is an intermediate for the manufacture of vitamins.
摘要:
A process for the manufacture of acetals by reacting aliphatic aldehydes with aliphatic alcohols, especially olefinically unsaturated aldehydes and allyl alcohols, in the presence of a distillable acid, especially nitric acid, using a rectifying column as the reaction vessel. The products may be used as starting materials for plastics, active substances, scents and vitamins.
摘要:
A process for the manufacture of a catalyst capable of causing condensation of aldehydes with ketones or ketones with each other while simultaneously hydrogenating the resulting olefinically unsaturated ketones to saturated ketones in the presence of hydrogen without attacking the ketone group, and containing zinc in addition to nickel or cobalt. The catalyst is subjected, prior to use, to a surface after-treatment with a zinc salt.
摘要:
Chromane derivatives (I) ##STR1## where R.sup.1, R.sup.2 and R.sup.3 are H or C.sub.1 -C.sub.8 -alkyl, R.sup.4 is H, C.sub.1 -C.sub.8 -alkyl or C.sub.1 -C.sub.8 -acyl and R.sup.5 is C.sub.1 -C.sub.8 -alkyl are prepared by reacting a hydroquinone (II) ##STR2## with a Lewis acid or a Lewis acid derivative having the same action, and with a nitrile CH.sub.2 .dbd.CH--C(R.sup.5)(OR.sup.6)CN (III), where R.sup.6 is H, C.sub.1 -C.sub.4 -acyl or C.sub.1 -C.sub.4 -alkyl, or with a compound from which III is formed in situ, in the presence of an inert solvent.
摘要:
A process for the preparation of an indolenine of the formula ##STR1## where R, X and Y are conventional substituents, by thermal rearrangement of a compound of the formula ##STR2## to give a compound of the formula ##STR3## and cyclization of this compound in the presence of an acid catalyst.
摘要:
A process for the manufacture of higher ketones by reacting an aldehyde with a ketone in the presence of hydrogen over a catalyst system which contains, firstly, oxides or salts of the rare earth metals and, secondly, metals of group VIII of the periodic table of the elements. The process gives numerous higher ketones, required, for example, as solvents for surface coatings, or as scents, with high conversions and good selectivities, and therefore more simply and more economically than conventional methods.