Hoechst Aktiengesellschaft

Jurgen Stenzel

Gero Heymer

Hans Herbst

Alexander Maurer

Siegfried Benninger

Christian May

Arnulf Hinz

Method of regulating the throughput in the electrochemical regeneration

Chromosulfuric acid, which is used in many organic reactions as an oxidizing agent, can advantageously be regenerated electrochemically if an electrolysis cell is used which comprises two tub-like half shells with a current-permeable, hydraulically sealing partition situated inbetween. The hydrogen produced at the cathode can also be extracted and utilized in this way.

Process for electrochemically regenerating chromosulfuric acid

The invention relates to a process for making long chain ammonium polyphosphate consisting essentially of crystalline modification II. To this end, a mixture of phosphorus pentoxide and ammonium orthophosphate in a molar ratio of 1:0.9 to 1:1.1 is reacted with 0.1 to 15 mol % of melamine or its condensation products selected from melam, melem or mellon, calculated as melamine, at a temperature within the range 50.degree. to 150.degree. C. in the presence of an excess of ammonia and the reaction product is heat-treated at temperatures within the range 200.degree. to 400.degree. C.

Process for making long-chain ammonium polyphosphate

Phosphine is continuously produced by reacting yellow phosphorus with an aqueous alkali metal hydroxide solution in the presence of an alcohol, with the exclusion of oxygen, at 44 to 90.degree. C. To this end, the reaction is effected in two separate reaction stages. In the first reaction stage, the alkali metal hydroxide solution and phosphorus are reacted with agitation in a molar ratio of 0.7:1 to 0.9:1 and the resulting gaseous phosphine is collected. Resulting liquid phase material containing unreacted phosphorus is delivered to the second reaction stage in which the unreacted phosphorus is reacted with further aqueous alkali metal hydroxide solution. The resulting gaseous reaction products are collected separately from the gaseous phosphine collected in the first reaction stage.

Continuous production of pure phosphine

Production of phosphine. The phosphine is produced by reducing, in a first step, anhydrous zinc phosphate to zinc phosphide by treatment with carbon at a temperature higher than 1000.degree. C, and, in a second step, reacting the zinc phosphide formed in the first step with phosphoric acid. The resulting gaseous phosphine is collected, and the resulting zinc phosphate, which is obtained as a difficultly soluble precipitate, is dried, dehydrated and recycled to the first step.

Production of phosphine

Production of solid, hollow and spheroidic material for use as a carrier supporting motor exhaust gas decontamination catalysts. To this end, spheroidal particles of material being oxidizable and/or low melting and/or soluble in organic solvents are placed on to a pelletizing table. Ceramic pulverulent material is distributed thereover and a aqueous cellulose ether solution is simultaneously sprayed thereonto to cause deposition of the ceramic material on the particles. The resulting pellets are dried at 20.degree. - 95.degree. C and freed from material being oxidizable and/or low melting and/or soluble in organic solvents, and finally calcined at 1000.degree. - 1500.degree. C.

Production of material consisting of solid hollow spheroids

Ferrophosphorus is utilized. To this end, a melt of ferrophosphorus is reacted with a melt of calcium silicide so as to obtain ferrosilicon and calcium phosphide.

Process for utilizing ferrophosphorus

Catalyst reducing the toxic contaminants of exhaust gas of combustion engines. The catalyst, which consists essentially of a ceramic honey comb structure as carrier and a mixture of copper, nickel and manganese oxides as catalytically active ingredients, has an intermediary layer of aluminum oxide applied to the honey comb carrier. The catalyst is produced by heating the honey comb carrier to 300.degree. - 400.degree.C; by introducing the hot carrier into a concentrated solution of an aluminum salt of a volatile acid for 15 - 60 minutes; by blowing out the carrier and drying it at room temperature; by heating the dry carrier within 1 to 4 hours to 350.degree. - 450.degree.C and then calcining it for 2 to 6 hours to 500.degree. - 700.degree.C with the resultant formation of an intermediary layer of aluminum oxide on the honey comb carrier; by heating the carrier to 300.degree. - 400.degree.C; by dipping the hot carrier in a hot concentrated aqueous solution of catalytically active copper, nickel and manganese salts of volatile acids and allowing it to remain therein for 15 - 60 minutes; by blowing out the carrier and drying it for 1 - 4 hours at 350.degree. - 450.degree.C; and by calcining it for 5 - 20 hours at 700.degree. - 1000.degree.C.

Growing community of inventors

Gersthofen, Germany

Jurgen Stenzel