Catalysts for the production of methylchlorosilanes using zinc oxide promoters
The present invention provides a catalyst that may be used to facilitate the formation of dimethylchlorosilanes. A catalyst in which copper oxide and zinc oxide are in intimate contact and form agglomerated particles allows for the increased selectively of the production of dimethylchlorosilanes.
1. A catalyst comprised of agglomerated particles, wherein said agglomerated particles are comprised of zinc oxide and copper oxide, and said copper oxide is comprised of cupric oxide and cuprous oxide.
2. The catalyst of claim 1 , wherein the catalyst is further comprised of elemental copper.
3. The catalyst of claim 2 , wherein:
(a) the cuprous oxide is present in an amount between 30 and 95 wt.% based on the weight of the catalyst;
(b) the cupric oxide is present in an amount between 2 and 45 wt.% based on the weight of the catalyst;
(c) the elemental copper is present in an amount less than or equal to 25 wt.% based on the weight of the catalyst; and
(d) the zinc oxide is present in an amount less than or equal to 18 wt.% based on the ratio of zinc oxide to a total copper content of the catalyst.
4. The catalyst of claim 3 , wherein the ratio of zinc oxide to the total copper content of the catalyst by weight is between 0.01:1 and 0.65:1.
5. The catalyst of claim 4 , wherein the ratio of zinc oxide to the total copper content of the catalyst by weight is between 0.01:1 and 0.25:1.
6. The catalyst of claim 2 , further comprising tin.
7. The catalyst of claim 1 , further comprising tin.
8. A process for making the catalyst of claim 1 , said process comprising agglomerating the zinc oxide and the copper oxide to form the agglomerated particles and high energy milling said agglomerated particles with elemental copper.
9. A process for making the catalyst of claim 1 , said process comprising the steps of:
(a) oxidizing and milling water atomized copper shot to form oxidized and milled water atomized shot;
(b) co-mixing and blending the oxidized and milled water atomized shot with zinc oxide powder to form a co-mixed and blended product;
(c) oxidizing the co-mixed and blended product to create the agglomerated particles, wherein said agglomerated particles contain an intimately mixed zinc-oxide phase and copper oxide phase; and
(d) milling said agglomerated particles with metallic copper to make the catalyst.
10. The process of claim 9 , further comprising milling the particles with the tin during step (d).
11. A catalyst comprised of agglomerated particles, wherein said agglomerated particles are comprised of zinc oxide and copper oxide, wherein said agglomerated particles are of a size less than 20 microns and have a surface area between 0.5 and 8 m 2 /g.
12. A process for making a catalyst, said process comprising agglomerating zinc oxide and copper oxide to form agglomerated particles, wherein said agglomerated particles have a surface area between 0.5 and 8 m 2 g.
13. The process of claim 12 , wherein said agglomerating is performed by the addition of heat.