Highly selective shell impregnated catalyst of improved space time yield for production of vinyl acetate
US6420308B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Jul 7, 2000 |
| Grant date | Jul 16, 2002 |
| Priority date | — |
| Expiry date | Jul 12, 2020 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB01J37/031
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A shell impregnated catalyst of Pd—Au produced on a silica support to have a Pd loading of 1.8 g/L of catalyst to about 7.2 g/L and a Au to Pd weight ratio of 0.3 to 2.0 by impregnating the support with aqueous solutions of palladium and gold salts or acids and thereafter precipitating water insoluble compounds of Pd and Au on the with alkali metal silicate or hydroxide solutions, then dried, and the surface precipitated compounds of Pd and Au are then reduced by reaction with ethylene or hydrogen at a temperature of greater than 150° C. up to 310° C. or with hydrogen up to 299° C. until substantially all of the Pd and Au contents are reduced to a free metal state, after which the support is impregnated with potassium acetate to an extent of 6 to 7 weight percent of the weight of the total catalyst. For production of vinyl acetate (VA) such catalyst has a space-time yield (STY) and specific activity (SA) about 20-30% greater than an otherwise identical catalyst composition that is formed from impregnated support reduced at 150° C., and in a temperature range of 140° C. to 160° C. at a gas hourly space velocity of 4500/hr will at 120 psig exhibit a VA s…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.