Abstract: Process for preparing melamine by converting urea in the presence of a solid catalyst in one reactor or in a plurality of reactors connected in series in the temperature range from 370° C. to 430° C., cooling and filtering the gas formed in the urea conversion, removing the melamine by desublimation and recycling a portion of the gas present after the melamine removal (“cycle gas”) into the reactor or the reactors, which comprises performing all of the above stages at a pressure in the range from 4 bar abs. to 10 bar abs.

Abstract: The invention relates to a process for oxidizing at least one organic substance with oxygen, which comprises the following steps: (a) adding the at least one organic substance as a liquid and an oxygenous gas stream to a first reaction stage to form a reaction mixture, at least some of the oxygen reacting with the organic compound to form a reaction product, (b) adding the reaction mixture from the first reaction stage to an adiabatically operated reaction stage in which the unconverted organic substance reacts further at least partly to give the product. The invention further relates to an apparatus for performing the process.

Abstract: A process for the preparation of melamine by decomposition of urea with the use of a catalyst, the catalyst comprising a) 10-90% by weight of zeolite, b) 10-90% by weight of a matrix comprising silica, alumina, silicon aluminum oxides and/or clay minerals, and c) 0-10% by weight of additives and the total content of nickel and vanadium in the catalyst being less than 500 ppm.

Abstract: The invention relates to a process for oxidizing at least one organic substance with oxygen, which comprises the following steps: (a) adding the at least one organic substance as a liquid and an oxygenous gas stream to a first reaction stage to form a reaction mixture, at least some of the oxygen reacting with the organic compound to form a reaction product, (b) adding the reaction mixture from the first reaction stage to an adiabatically operated reaction stage in which the unconverted organic substance reacts further at least partly to give the product. The invention further relates to an apparatus for performing the process.

Abstract: Process for preparing melamine by converting urea in the presence of a solid catalyst in one reactor or in a plurality of reactors connected in series in the temperature range from 370° C. to 430° C., cooling and filtering the gas formed in the urea conversion, removing the melamine by desublimation and recycling a portion of the gas present after the melamine removal (“cycle gas”) into the reactor or the reactors, which comprises performing all of the above stages at a pressure in the range from 4 bar abs. to 10 bar abs.

Abstract: A process for the preparation of melamine by decomposition of urea with the use of a catalyst, the catalyst comprising a) 10-90% by weight of zeolite, b) 10-90% by weight of a matrix comprising silica, alumina, silicon aluminum oxides and/or clay minerals, and c) 0-10% by weight of additives and the total content of nickel and vanadium in the catalyst being less than 500 ppm.