Granted Patent B2

US 8,715,388 · App. 13/097,333 · Granted May 6, 2014

Abstract

Claims (18)

1. A process for recovery of a precious metal catalyst from an organosilicon product-containing liquid reaction medium containing precious metal catalyst in solution or colloidal form, the process comprising:

a) contacting the liquid reaction medium containing precious metal catalyst with a precious metal adsorbent under precious metal adsorption conditions to adsorb precious metal thereon wherein the precious metal adsorbent is an adsorbent with an inorganic backbone matrix;

b) separating precious metal adsorbent from the liquid reaction medium; and,

c) recovering adsorbed precious metal from said precious metal adsorbent,

wherein no dilution solvent is added to the organosilicon product-containing liquid reaction medium containing precious metal catalyst.

2. The process of claim 1 further comprising:

d) re-contacting the liquid reaction medium resulting from the completion of step b) with precious metal adsorbent at precious metal adsorption conditions to adsorb precious metal thereon;

e) separating precious metal adsorbent from the liquid reaction medium; and,

f) recovering adsorbed precious metal from said precious metal adsorbent.

3. The process of claim 2 wherein recontacting the liquid reaction medium with said precious metal adsorbent is completed in a continuous manner.

4. The process of claim 1 wherein the liquid reaction medium in step (a) is provided directly from a continuous siloxane copolymer unit, a continuous silane distillation unit or a continuous silane hydrosilation unit.

5. The process of claim 1 wherein the precious metal is platinum, rhodium or palladium.

6. The process of claim 1 wherein the precious metal adsorbent comprises at least one of a functionalized silica gel and inorganic nanoparticles.

7. The process of claim 1 wherein said precious metal adsorption conditions includes a temperature range of from about ambient to about 200° C.

8. The process of claim 1 wherein said precious metal adsorption conditions includes a pressure range of from about atmospheric to about 100 atmospheres.

9. The process of claim 1 wherein said precious metal adsorption conditions includes a residence time of the liquid reaction medium to be contacted with said precious metal adsorbent of about 1 minute to 24 hours.

10. The process of claim 1 wherein the viscosity of the liquid reaction medium is about 1 cSt to about 500 cSt at 25° C.

11. The process of claim 1 wherein contacting the liquid reaction medium with said precious metal adsorbent is completed in a continuous manner.

Assignments (18)