Copper aspirinate use of copper aspirinate as a pigment in PVC and Polystyrene has also been investigated. 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
Pyrophosphoric acid Pyrophosphoric acid Pyrophosphoric acid, also known under the name diphosphoric acid, is colorless, odorless, hygroscopic and is soluble in water, diethyl ether, and ethyl alcohol. The anhydrous acid has two different forms, which melt at 54.3 °C and 71.5 °C. It is best prepared by ion exchange from sodium pyrophosphate or by reacting hydrogen sulfide with lead pyrophosphate. When phosphoric acid is dehydrated pyrophosphoric acid is produced as one of the products. When molten, pyrophosphoric acid rapidly forms an equilibrium mixture of phosphoric acid, pyrophosphoric acid and polyphosphoric acids. The percentage by weight of pyrophosphoric acid is around 40% and