Process for the direct synthesis of organochlorosilanes using recovered CuCI catalyst
AssigneeWacker Chemie AG
InventorsWilfried Kalchauer, Herbert Straussberger, Willibald Streckel, Ulrich Goetze
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Abstract
A process for the direct synthesis of organochlorosilanes using CuCl prepared from the copper-containing residues from the direct synthesis of organochlorosilanes, where, in the preparation of the CuCl, in a first step, copper from an aqueous suspension of the copper-containing residues is oxidized to CuCl2 using mineral acid and oxidant, where mineral acid or oxidant or mineral acid and oxidant contain chlorine, giving an aqueous CuCl2 solution, and in a second step, the aqueous CuCl2 solution is reduced to CuCl using elemental iron.
Claims18
A process for the direct synthesis of organochlorosilanes employing a catalyst comprising CuCl as a catalyst component, wherein at least a portion of said CuCl is recycled CuCl prepared from the copper-containing residues from the direct synthesis of organochlorosilanes, wherein the preparation of the recycled CuCl comprises,
- in a first step, oxidizing copper from an aqueous suspension of the copper-containing residues from a direct organochlorosilane synthesis to CuCl2 using mineral acid and oxidant, wherein said mineral acid, said oxidant, or said mineral acid and said oxidant contain chlorine, thus providing an aqueous CuCl2 solution, and
- in a second step, reducing said aqueous CuCl2 solution to CuCl using elemental iron.
A process for the preparation of organochlorosilanes by the direct process employing a copper (I)—containing catalyst and optionally cocatalysts and promoters without substantial loss of copper during continuous operation or in successive batch or continuous campaigns, said process comprising
- a) introducing silicon metal, at least one chloroorganic compound, and a catalyst comprising copper metal and optionally cocatalysts and/or promoters into a heated reactor;
- b) recovering organochlorosilanes from said reactor and metal-containing solids containing zero-valent metals and metal compounds;
- c) suspending said metal-containing compounds in a composition comprising mineral acid and an oxidant, at least one of said mineral composition or said oxidant containing chlorine, thus providing an aqueous copper (II) solution;
- d) adding iron metal to said aqueous copper (II) solution at a pH of between 1 and 3 to obtain a solution containing Cu(I);
- e) optionally filtering said solution containing Cu(I) to remove solids;
- f) precipitating CuCl from said solution containing Cu(I), separating precipitated CuCl from the mother liquor containing said CuCl, drying said precipitated CuCl and adding at least a portion of said CuCl to a direct organochlorosilane process (a) as a copper catalyst;
- g) adding a metal lower in the electromotive series than copper to said mother liquor of step f) to precipitate remaining copper as copper(0);
- h) recycling said copper (0) by one or both of
- h1) introducing said copper (O) to a direct process reactor to supply at least a portion of said copper catalyst, or
- h2) introducing said copper (0) to step (C) and/or to step (d) and comproportionating with Cu(II) to form Cu(I).
Dependencies are inferred from the claim text.