Hoechst Aktiengesellschaft

Hoeschst Aktiengesellschaft

Robert K Driscoll

Ernst I Leupold

Wolfgang Ebertz

Friedrich Wunder

Matthias Gutweiler

Karl-Heinz Schonwalder

Joachim Schutz

Ingo Leupold

Acetals of polyvinyl alcohol are described in which at least some of the acetal groups are derived from terminally etherified oxyethylene aldehydes/oxaalkanals of the formula ##STR1## The new acetals are internally plasticized and can be processed thermoplastically without external plasticizers. Depending on the nature of the radical R, which can be aliphatic, cycloaliphatic or aromatic, and the size of n, an integer, preferably 1 to 3, and, on the nature of other aldehydes which may be co-used for mixed acetalation, the new acetals are soluble in water or organic solvents.

Polyvinyl acetals and their use

A process for the separation of butanol and butoxyacetaldehyde which involves subjecting a composition which contains these two compounds to a distillation at a pressure of at most 660 mbar. According to a special embodiment the composition to be distilled contains as essential components water, butanol, butoxyacetaldehyde, butylglycol and, if desired, also butyraldehyde.

Process for the separation of butanol and butoxyacetaldehyde

The invention relates to a process for the preparation of a glyoxylic acid ester by oxydehydrogenation of the corresponding glycolic acid ester in the gas phase over a supported catalyst in a tubular reactor. The catalyst support consists of at least one cylindrical monolith which essentially has the same diameter as the reactor tube and contains channels with a diameter of 1 to 10 mm leading from the inlet to the outlet of the reactor tube. 60 to 90% of the monolith volume is formed by hollow spaces.

Process for the preparation of a glyoxylic acid ester

The invention relates to hemiacetals of glyoxylic esters and to a process for obtaining a glyoxylic ester having a C.sub.1 to C.sub.4 ester group from a mixture which essentially contains a glyoxylic ester of this type plus water and/or a C.sub.1 to C.sub.4 alcohol ROH. In this, the glyoxylic ester and the water and/or the alcohol are partly or completely in a chemically bonded form. A higher alcohol R'OH having a boiling point above 180.degree. C. is added, and distillation is carried out under a pressure not exceeding 800 mbar to remove first the water and/or the alcohol ROH and then the glyoxylic ester.

Hemiacetals of glyoxylic esters and a process for the isolation of

The invention relates to a process for the preparation of glyoxylic hemiacetal esters, in which first glycolic esters are oxydehydrogenated to give glyoxylic esters, and then the latter are reacted with an alcohol. The gaseous reaction mixture formed in the oxydehydrogenation is introduced, together with an excess of an alcohol which is suitable as an entraining agent, into a distillation column and then the water of reaction is distilled overhead together with other low-boilers and part of the excess alcohol, the glyoxylic hemiacetal ester and the remainder of the excess alcohol resulting as the bottom product. In a variant of the process, use is made of an additional inert entraining agent whose azeotrope with water boils below 90.degree. C. and below the alcohol which is used, and then the water of reaction is distilled overhead with the assistance of this entraining agent.

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Frankfurt am Main, Germany

Robert K Driscoll