Silica gels of controlled pore size as desiccant materials and processes for producing same
US5364455A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 22, 1992 |
| Grant date | Nov 15, 1994 |
| Priority date | — |
| Expiry date | Sep 22, 2012 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S95/90
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
The present invention relates to a controlled process for producing amorphous, microporous silica gels having a predetermined water sorption isotherm of moderate Type I shape having a separation factor between about 0.07 and 0.1 and micropore diameter size between about 6 and 8.7 angstroms. The present microporous silica gels are prepared by adjusting the pH of the reaction system or by doping the system with various elements during the hydrolysis and condensation of alkoxy silicates to form silica gels therefrom, and the hydrolyzed products are successively polymerized to form polymers and particles containing siloxane bonds as follows: ##STR1## Various factors, for example open vs closed system, amount of water used for hydrolysis, type of alkoxides and solvent, pH, amount of catalyst, temperature, aging and drying conditions etc., affect the nature and the rate of hydrolysis, condensation reactions and network formation, and consequently the properties of the final gel products.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.