Chemie Ag Bitterfeld-wolfen

Leuna-katalysatoren Gmbh

Buck Werke Gmbh Und Co.

Rudolf Schumann

Arndt Zschalich

Peter Birke

Reinhard Geyer

Rainer Schoedel

Ulrich Neumann

Klaus Weber

Gerhard Vogel

Willi Sattelmayer

Anette Hoppe

Werner Haertwig

A method for the hydrodechlorination of a reaction gas primarily composed of chlorinated hydrocarbons is carried out sequentially. A first step is advantageously carried out in a tubular reactor filled with catalyst and cooled externally, to maintain a temperature within a preferred range of 80.degree. to 230.degree. C. and a radial temperature difference of not more than 40.degree. C. Hydrogen is added to the tubular reactor with a hydrogen excess in a preferred range of 1.1 to 1.5 relative to the reaction gas, based on the stoichiometric consumption. The catalyst is present in a catalyst loading in a preferred range of 0.1 to 1.5 v/vh based on the volume of reaction gas. A fixed bed reactor is advantageously used for a second step, optimally connected in straight transit with the output of the reactor of the first step. The full-space reactor is maintained at a temperature within a preferred range of 200.degree. to 300.degree. C. and a hydrogen excess relative to the stoichiometric consumption is in a preferred range of 2 to 100. Catalyst is present in a preferred amount related to a volume of catalyst in step one according to a ratio in a range of 2:1 to 10:1. The dechlorination is preferably carried out at pressures between 1 and 50 bar. A method is further provided for regenerating deactivated catalysts without accumulation of dioxin in the waste gas, achieved by a reducing treatment, followed by an oxidizing treatment at a temperature at or above the last operating temperature of the catalyst.

Method for the complete hydrodechlorination of chlorinated hydrocarbons

A method for purifying phosphorus to insure a low sulfur content involves intensively mixing phosphorus and concentrated sulfuric acid to form an emulsion, breaking the emulsion by contact with water or dilute sulfuric acid, and then immediately separating the phosphorus and diluted sulfuric acid. The separated phosphorus is then stored in water until further processing is desired and is characterized by a sulfur content as low as about 50 ppm.

Method for decreasing the sulfur content of phosphorous

A method for purifying white phosphorus contaminated with sulfur bound thereto involves contacting contaminated white phosphorus with water, steam, aqueous solutions, or vaporized aqueous solutions, preferably alkaline, to remove bound sulfur from the phosphorus. The purified phosphorus is characterized by a sulfur content as low as 50 ppm.

Method for the removal of sulfur from phosphorus

The invention relates to a method for stabilizing phosphorus trichloride. In order to delay the formation of phosphorus oxychloride in phosphorus trichloride and to reduce it to a minimum value which no longer adversely affects further processing, one or more amines which have at least two aromatic hydrocarbon groups linked to one nitrogen atom, such as diphenylamine, phenothiazine, phenyl-4-methylphenylamine and triphenylamine, are added to the phosphorus trichloride. The amines can also be added in the form of their salts, including their quaternary ammonium compounds, or their reaction products with phosphorus halides. The amounts of amines, added fall within the range of 10.sup.-6 % to 10.sup.-1 %, based on the amount of phosphorus trichloride.

Method for stabilizing phosphorus trichloride

The invention relates to a method for the stabilization of phosphorus trichloride, wherein one or more derivatives of dithiocarbamic acids are added to the phsophorus trichloride. As derivatives, salts, esters or thiuram sulfides of the dithiocarbamic acids, individually or as a mixture, are preferred. The amounts used generally fall within the range of 10.sup.-4 % to 10.sup.-2 %, based on the amount of phosphorus trichloride. Derivatives, which are only slightly soluble in phosphorus trichloride are advantageously used in amounts of more than 10.sup.-2 %. Due to the inventive addition of derivatives of dithiocarbamic acids, the formation of phosphorus oxychloride in the phosphorus trichloride is delayed significantly and reduced to a minimum value.

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Raguhn, Germany

Rudolf Schumann