Hoechst Aktiengesellschaft

Bayer Aktiengesellschaft

Degussa Aktiengesellschaft

Josef Riedl

Siegfried Rebsdat

Sigmund Mayer

Josef Alfranseder

Wenzel Kuhn

Walter Frohlich

Iwo Schaffelhofer

Erich Mittermaier

Peter Widmann

Klaus Deller

Peter Schwarzmaier

Herbert Mueller

Hans Moesinger

Reinhard Krumbock

Rudolf Spielmannleitner

Wenzel Kuehn

Apparatus for carrying out a method for the catalytic conversion of waste gases such as those which accumulate in the synthesis of vinyl chloride is presented in which the waste gases are successively treated at an elevated temperature with a catalyst for oxidative cracking and with a catalyst for oxidative afterburning.

Apparatus for the catalytic conversion of waste gases containing

A process for the manufacture of 1,2-dichloroethane from ethylene by reaction with hydrogen chloride and inert gases containing oxygen, and also by reaction with chlorine, is described. The two chlorination reactions are carried out successively at 180.degree. to 360.degree. C. and under a pressure of 0.09 to 1.1 MPa in a common reaction space containing fluidized catalyst particles. A stoichiometric excess of ethylene is employed for the first chlorination reaction. The heat formed in the reaction space is removed by indirect cooling. The process is simple in terms of apparatus and permits a better re-use of the total heat of reaction of the chlorination of ethylene.

Process for the manufacture of 1,2-dichloroethane

A process for the purification of 1,2-dichloroethane is described, in which the crude product, containing not more than 3% by weight of high-boilers, is distilled in a first column at 125.degree. to 180.degree. C. in such a way that the bottom product contains not more than 7% by weight of high-boilers. The purified, vaporous 1,2-dichloroethane discharged at the head of this column is used to heat product streams containing 1,2-dichloroethane. The bottom product from the first column is distilled in a second column, advantageously at a pressure of 5 to 40 kPa, together with a feed composed of vaporous 1,2-dichloroethane obtained from the reaction of ethylene with chlorine. The process makes it possible to purify 1,2-dichloroethane with a saving in energy.

Process for the purification of 1,2-dichloroethane

Supported silver catalysts, which should have as high an activity as possible, are employed for the manufacture of ethylene oxide by oxidizing ethylene by means of oxygen or air. A process is described for improving the activity of supported silver catalysts which have already been used, in which the used catalyst is first washed with an inert liquid containing ammonia and/or aliphatic amines and 1 to 1,000 parts, per 1 million parts of catalyst, of cesium, rubidium or a mixture thereof is then deposited on the washed catalyst. The deposition is generally effected with the aid of an impregnating solution containing the cesium and/or rubidium compounds in a suitable quantity. This process makes it possible to improve considerably the activity of supported silver catalysts which have already been in use for the oxidation of ethylene by means of oxygen or air.

Process for improving the activity of supported silver catalysts

A process for the manufacture of 1,2-dichloroethane is described, in which 1 mol of ethylene, 0.35 to 0.7 mol of chlorine, 0.7 to 1.4 mol of hydrogen chloride and 0.2 to 0.6 mol of oxygen, optionally together with inert gas, are reacted in a reaction zone containing surfaces capable of being heated and cooled, at 180.degree. to 260.degree. C. and under a pressure of 0.09 to 1.1 MPa, in the presence of a fixed bed catalyst containing copper. The process allows better utilization of the heat generated in the chlorination of ethylene.

Vinyl chloride is produced by pyrolytic decomposition of 1,2-dichloroethane in a furnace with coiled up reaction tube having an internal diameter of from 12 to 16 cm. The dichloroethane is vaporized completely in the convection zone of the pyrolytic furnace, different amounts of heat are supplied to the different zones of the reaction tube and, after decomposition in the working up of the reaction products, the low-boiling constitutents are treated with chlorine and separated together with the high-boiling constituents.

Process for the manufacture of vinyl chloride

The activity of supported silver catalysts, which have been used for the direct oxidation of ethylene to ethylene oxide with molecular oxygen or air and to which from 1 to 1,000 parts, per 1 million parts of catalyst, of cesium and/or rubidium have been applied, is improved by washing the catalyst with an inert liquid prior to the application of cesium and/or rubidium.

Process for improving the activity of used supported silver catalysts

The activity of supported silver catalysts for the direct oxidation of ethylene to ethylene oxide with molecular oxygen or air is improved by applying to the catalyst from 1 to 1,000 ppm, preferably 20 to 500 ppm, of cesium and/or rubidium in two or more than two steps and using the catalyst after each impregnation step again for the production of ethylene oxide by direct oxidation of ethylene with molecular oxygen or air.

The activity of supported silver catalysts used up in the direct oxidation of ethylene with molecular oxygen or air is improved by impregnating the catalyst arranged in a fixed bed with a solution of a caesium and/or rubidium compound in an inert organic solvent, optionally together with up to 40% by weight of water, calculated on the total liquid, as dissolving intermediary, so as to produce a concentration gradient of from 0.3 to 20 parts of caesium and/or rubidium per 1 million parts of catalyst and per meter of fixed bed, counter to the direction of flow of the gas to be reacted. In this manner the activity of the catalyst is considerably improved which results in an increased selectivity of the oxidation of ethylene to ethylene oxide.

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Burgkirchen, Germany

Josef Riedl