Degussa Aktiengesellschaft

Skw Trostberg Aktiegesellschaft

Jens Weitkamp

Stefan Ernst

Peter K Kleinschmit

Akos Kiss

Thomas Kromminga

Thomas Bock

Horst Michaud

Benedikt Hammer

Heinrich Rock

Werner Goll

Kurt Scheinost

Molecular sieves are modified by an ion exchange process where metal cations are introduced into the molecular sieves by means of solid state ion exchange. The solid state ion exchange can be carried out as follows: a weighed amount of calcined and activated zeolite is intimately mixed with a precalculated amount of PtCl.sub.2, PdCl.sub.2, RhCl.sub.3, CuCl.sub.2, V.sub.2 O.sub.5 or another compound of the noble metals (e.g., corresponding halides or oxides), the solids mixture is then heated in a current of inert gas (e.g., a current of helium gas or of nitrogen) to temperatures of 400.degree. to 600.degree. C., then cooled down to room temperature and subsequently reduced in a current of hydrogen for 10 to 14 hours at 280.degree. to 350.degree. C. in order to produce small metal clusters from the cationically introduced metal.

Method of modifying molecular sieves by means of solid state ion

Modified molecular sieves by means of solid ion exchange

Method of modifying molecular sieves by means of solid state ion exchange

The present invention provides a process for the production of cyanamide from urea and/or decomposition products thereof at an elevated temperature with the use of a microporous catalyst, wherein, as catalyst, there is used a zeolite and/or a silicoalumophosphate which is doped with transition metal cations selected from the Group IB and VIIB of the Periodic System. In this way, it is possible to increase the conversion, referred to urea, to 60 to 100%, the selectivity with regard to cyanamide thereby being from about 30 to 50% and with regard to the undesired melamine being .ltoreq.2%.

Process for the production of cyanamide

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Horb am Neckar, Germany

Jens Weitkamp