Dynamit Nobel Aktiengesellschaft

Klaus Thewalt

Gunter Bison

Gunther Meyer

Reinhard Schmidt

Rudolf Burkhardt

Hans Leuck

Norbert Linkat

Josef Winterscheid

Paul Janssen, Deceased

Heinz Egger

Johannes Schlupp

Hans-Jorg Westerman

5-Methyltetrazole can be produced by reacting acetonitrile with an alkali azide or ammonium azide in high purity and a yield of above 98% by using a trialkyl amine as the solvent or suspension agent and by using the associated hydrochloride of the amine as the catalyst.

Process for the production of 5-methyltetrazole

A safe production of sodium nitro-1,3-propanediol from a reaction solution of nitromethane and paraformaldehyde in methanol by addition of sodium methylate is achieved by evaporative cooling of the methanol; it being possible to maintain reaction temperatures of 35.degree. C. to 50.degree. C.

Process for producing the sodium salt of 2-nitro-1,3-propanediol

It is suggested to produce 5-chloro-1H-tetrazolecarboxylic acid esters by reaction of dichloroisonitriloacetic acid esters with alkali or metal azides or ammonium azide. The dichloroisonitriloacetic acid esters required for this purpose are formed by reacting N-formylaminocarboxylic acid esters with chlorine or with compounds which split off chlorine.

Process for the preparation of dichloroisonitrilocarboxylic acid esters

2-Aminopropanediol-1,3 (serinol) can be prepared by hydrogenation of the alkali salt of 2-nitro-1,3-propanediol with assuredly high yields by maintaining a narrow range of temperatures of extending from 50.degree.-80.degree. C. by use of a cooling device.

Process for the preparation of 2-aminopropanediol-1,3(serinol)

Oligomeric alkylene terephthalates having an average degree of condensation of 4 to 7 are produced by passing dimethylterephthalate and diol having at least 3 carbon atoms downwardly through a series of reaction chambers, each outfitted with stirring and heating means employed so that the temperature increases from stage to stage. Thereby transeterification is effected. The chambers are interconnected so that the methanol evolved in each chamber is vented without being admixed with the material undergoing transesterification in any of the other chambers. The transesterification product is then condensed at elevated temperature and under vacuum to produce the oligomer. The oligomers are high reactivity so that the further condensation thereof to polyesters is simplified.

Method for the preparation of oligomeric alkylene terephthalates

An improvement in the method of preparing a linear polycondensate of high molecular weight wherein a precondensate is initially formed and thereafter subjected to a one-step melt condensation in a vacuum while cleavage products are removed therefrom, the reaction mass being exposed in a thin layer by means of a stirrer to the reaction conditions, the improvement residing in employing as the precondensate a molten precondensate having an average condensation degree of at least 3, said precondensate being introduced into the melt condensation zone continuously while the cleavage products are driven off at the particular optimum, product-specific condensation temperature, the contents of the melt condensation zone being subjected to the action of a rotary stirrer until the melt has a melt viscosity of 1000 to 15000 poises and continuously withdrawing molten polycondensate in accordance with the speed of the reaction. Also disclosed is an apparatus in which the polycondensation is effected including an offset withdrawal outlet containing an auger which can enter a funnel disposed between the outlet and the polycondensation zone. Also disclosed is an upright multi-chamber vessel in which the precondensate is formed wherein the chambers are disposed one over the other. Some of the upper chambers are equipped with means for maintaining a normal or elevated pressure while some of the lower chambers are equipped with means for imposing a partial vacuum on the contents.

Growing community of inventors

Witten, Germany

Klaus Thewalt