Production of trialkyphosphines of the general formula R.sub.3 P, in which R stands for alkyl groups having from 1 to 3 carbon atoms. In a first step a vaporous or gaseous mixture of phosphorus and an alkyl halide is passed in the absence of oxygen or air and at a temperature between 280.degree. and 420.degree.C, over an active carbon catalyst, the resulting gaseous reaction mixture is subjected to fractional condensation so as to isolate monoalkylhalogenophosphine, dialkylhalogenophosphine and a two layer-forming mixture of trialkylphosphonium halide and unreacted phosphorus therefrom, the trialkylphosphonium halide is decanted and, in a second step an aqueous alkali is added to the trialkylphosphonium halide so as to produce trialkylphosohine therefrom.
Production of dialkylphosphines. In a first step, a mixture of phosphorus and an alkyl halide is passed at 300 - 450.degree.C over active carbon and the resulting gaseous reaction mixture is initially freed from trialkylphosphonium halide and unreacted phosphorus, and then freed from a homogeneous mixture comprised of a dialkylhalaogenophosphine/hydrogen halide-addition product and dialkylphosphonium halide. In a second step, the mixture is solvolyzed with an alcohol, a pH of at least 2 is established in the solvolyzed material, and dialkylphosphine is separated from the solution obtained.
Alkyl phosphines are made. To this end, phosphorus in vapor form is reacted with steam and an alkyl amine at elevated temperature in contact with a carbon catalyst placed in a reactor, the reactants being used individually or in admixture with one another.
Production of organophosphines of the general formula R.sub.n PH.sub.3-n, in which R stands for identical or different, substituted or unsubstituted alkyl, cycloalkyl or aralkyl groups having from 1 to 18 carbon atoms, preferably from 1 to 4 carbon atoms, more preferably from 1 to 2 carbon atoms, and n stands for a whole number within the range 1 and 3. The compounds are more particularly produced by continuously reacting hydrocarbon halides of the general formula RX, in which R has the meaning given hereinabove and X stands for halogen, especially for chlorine or bromine, with hydrogen phosphide, and primary or secondary organophosphines at temperatures within the range 100.degree. and 600.degree. C. and under pressures of up to 20 atmospheres in contact with a catalyst being placed in a reactor. Gaseous matter issuing from the reactor is cooled and the resulting organophosphonium halides (R.sub.n PH.sub.4-n)X are hydrolyzed in conventional manner to the corresponding organophosphines.
Alkyl phosphines of the general formula: are made. To this end hydrogen phosphide, a primary or a secondary phosphine is reacted with an alkylamine of the general formula: in a molar ratio of 0.1 to 10 mols of the alkylamine of formula II per mol of hydrogen phosphide or primary or secondary phosphine. The reaction is effected at a 150.degree. to 400.degree. C., at atmospheric pressure or a superatmospheric pressure up to 1 atmosphere gauge, and in contact with a catalyst comprising active carbon, copper (II) chromite, or one or more metals of Group Ib or VIII of the Periodic System of the elements. The starting materials are passed through a reaction zone at a rate which permits a contact time between them and the catalyst of 0.1 to 400 seconds.
Production of quaternary phosphonium halides of the general formula: in which R.sup.1, R.sup.2, R.sup.3 and R.sup.4 stand for identical or different alkyl groups having from 1 to 4 carbon atoms and X stands for halogen, especially for chlorine or bromine. The compounds are more especially made by flowing hydrogen phosphide or a primary phosphine R.sup.1 PH.sub.2 or secondary phosphine R.sup.1 R.sup.2 PH or tertiary phosphine R.sup.1 R.sup.2 R.sup.3 P and an alkyl halide R.sup.4 X in a molar ratio from 0.02 to 10, at a temperature from 100.degree. to 500.degree. C, under a pressure of up to 10 atmospheres gauge and for a period from 0.5 to 500 seconds over a catalyst and separating the resulting quaternary phosphonium halides from the reaction gas. The halides so made are used for making trialkylphosphine oxides and trialkylphosphines.
