Degussa Aktiengesellschaft

Mathias Hoepp

Dietrich Arntz

Wolfgang Boeck

Willi Hofen

Klaus Koehler

Adolf Schaefer-Sindlinger

Hans-Peter Ohlinger

Stephan Bartsch

Klaus Raible

Andreas Bosse-Plois

A process for the preparation of 1,1,3-trialkoxypropane by acid-catalyzed reaction of acrolein with a C.sub.1 to C.sub.6 alcohol, which can be carried out well on a large scale and leads to a higher selectivity. The process involves (a) the reaction, in the presence of a solid acid catalyst which is insoluble in the reaction mixture, (b) a partial neutralization of the reaction mixture, using an amine or basic ion exchanger, and (c) specific recovery by distillation of the reaction mixture and recirculation of fractions containing useful materials; aqueous fractions containing recyclable useful materials are largely dehydrated by pervaporation prior to being recirculated.

Process for the preparation of 1,1,3-trialkoxypropane

2-(Alkoxymethyl)acrolein of the formula ##STR1## is produced from acrolein, an alcohol ROH and formaldehyde, in one step, with a good yield being obtained. The acrolein is reacted with a substantially equimolar quantity of a source of formaldehyde in the presence of at least an equimolar quantity of the alcohol ROH and a catalytic quantity of a catalyst system based on a secondary amine and a mineral acid at a pH value of the reaction mixture in the range of 1 to less than 7.

Process for the production of 2-(alkoxymethyl)acrolein

Process for the production of 2-vinyl-1,3-dioxolane reacting acrolein with ethylene glycol in the presence of a solid, acidic catalyst and recovery of the reaction mixture. Selectivity may be increased in comparison with known prior art processes by performing the reaction in the presence of a solid acidic catalyst at a temperature of below 50.degree. C.; the reaction mixture, from which the catalyst has been removed, is treated by extraction using an organic solvent which substantially does not dissolve ethylene glycol and has a boiling point of above 130.degree. C.; the two phases obtained on extraction are treated for recovery by distillation and recovered educts and the organic solvent are recycled.

Process for the production of 2-vinyl-1,3-dioxolane

Mixed cyclic acrolein glycerol acetals can be obtained by reacting acrolein with glycerol in the presence of a solid acidic catalyst and by a distillation workup in a higher space-time yield and in very high selectivity in comparison to the state of the art if the reaction is carried out in the presence of the reaction mixture as solvent, which mixture consists essentially of acrolein, glycerol, cyclic acrolein glycerol acetals and water, and in the absence of heterogeneous solvents and, to the extent necessary, the reaction mixture freed of catalyst is compounded prior to being worked up by distillation with such an amount of pH-increasing substance that it exhibits a pH in a range of 4.5 to 7 in tenfold dilution with water. The reaction preferably takes place at 10.degree. to 30.degree. C. using strongly acidic organic or inorganic ion exchangers.

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Biebergemuend, Germany

Mathias Hoepp