Abstract: 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.

Abstract: 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.

Abstract: A process for the recovery of pure 2-methyl-2-hydroxyheptanone-6 by conversion of impure 2-methyl-2-hydroxyheptanone-6 into 2,2,6-trimethyl 2,3-hydro-4-H-pyran by treatment with an acid which is not volatile under the reaction conditions at a temperature of from 30.degree. to 150.degree.C, purification of the 2,2,6-trimethyl-2,3-hydro-4-H-pyran thus obtained by distillation, reaction of the purified 2,2,6-trimethyl-2,3-hydro-4-H-pyran with water in the presence of an acid ion exchanger and removal of the excess water from the aqueous solution of 2-methyl-2-hydroxyheptanone-6 thus obtained by distillation. 2-methyl-2-hydroxyheptanone-6 is suitable for the production of 2-methyl-2-hydroxy-6-aminoheptane which is effective as a pharmaceutical for conditions of the heart and circulation.