Copper aspirinate Copper aspirinate Copper(II) aspirinate is an aspirin chelate of copper(II) cations (Cu). It is used to treat rheumatoid arthritis. Copper aspirinate can be prepared by several methods. In one route of preparation, an excess of acetylsalicylic acid is dissolved in aqueous sodium carbonate. Sodium hydroxide is not suitable for this purpose, because it will hydrolyse acetylsalicylic acid ("ASA") into salicylic acid and sodium acetate. The resulting solution is then filtered to remove any undissolved acetylsalicylic acid and is mixed with a solution containing Cu cations (copper(II) sulfate is suitable), precipitating bright blue crystals of copper aspirinate immediately. The crystals can
Silicotungstic acid Silicotungstic acid Silicotungstic acid (also known as tungstosilicic acid) is the most commonly encountered heteropoly acid. It is a pale yellow solid with the chemical formula H[WSiO]. It is used as a catalyst in the chemical industry. Silicotungstic acid is used to manufacture ethyl acetate by the alkylation of acetic acid by ethylene: It has also been commercialized for the oxidation of ethylene to acetic acid: 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 has also recently been proposed as a mediator