Silicotungstic acid
Template:Short description <templatestyles src="Chembox/styles.css"/>
Template:Chembox image cellTemplate:Chembox image cellTemplate:Chembox AllOtherNamesTemplate:Chembox headerbarTemplate:Chembox IndexlistTemplate:Chembox JmolTemplate:Chembox ChEMBLTemplate:Chembox ECHATemplate:Chembox E numberTemplate:Chembox IUPHAR ligandTemplate:Chembox UNIITemplate:Chembox CompToxTemplate:Chembox headerbarTemplate:Chembox headerbarTemplate:Chembox HazardsTemplate:Chembox headerbarTemplate:Chembox Datapage checkTemplate:Yesno| Template:Longitem | Template:Unbulleted list |
| ChEBI | Template:Unbulleted list |
| ChemSpider | Template:Unbulleted list |
| DrugBank | Template:Unbulleted list |
| EC Number | Template:Unbulleted list |
| KEGG | Template:Unbulleted list |
| Template:Longitem | Template:Unbulleted list |
| RTECS number | Template:Unbulleted list |
| Script error: No such module "collapsible list". | |
| Script error: No such module "collapsible list". | |
| Template:Longitem | Template:Chem2 |
| Molar mass | 2878.2 g/mol |
| Appearance | White solid |
| Melting point | Template:Chembox CalcTemperatures |
| Template:Longitem | 0 D |
| Template:Longitem | Phosphotungstic acid |
| Template:Longitem | Tungsten trioxide Tungstic acid |
Template:Chembox Footer/tracking container onlyScript error: No such module "TemplatePar".Template:Short description
Silicotungstic acid or tungstosilicic acid is a heteropoly acid with the chemical formula Template:Chem2. It forms hydrates Template:Chem2. In freshly prepared samples, n is approximately 29, but after prolonged desiccation, n becomes 6.[1] It is a white solid although impure samples appear yellow. It is used as a catalyst in the chemical industry.[2]
Applications
Silicotungstic acid is used to manufacture ethyl acetate by the alkylation of acetic acid by ethylene:
It's also been commercialized for the oxidation of ethylene to acetic acid:[2]
This route is claimed as a "greener" than methanol carbonylation. The heteropoly acid is dispersed on silica gel at 20-30 wt% to maximize catalytic ability.
It was recently proposed as a mediator in production of hydrogen through electrolysis of water by a process that would reduce the danger of explosion while allowing efficient hydrogen production at low current densities, conducive to hydrogen production using renewable energy.[3]
Synthesis and structure
The free acid is produced by combining sodium silicate and tungsten trioxide followed by the treatment of the mixture with hydrochloric acid.[1][4] The polyoxo cluster adopts a Keggin structure, with Td point group symmetry.
Hazards
Silicotungstic acid is an irritating and odorless substance.
References
<templatestyles src="Reflist/styles.css" />
Script error: No such module "Check for unknown parameters".