PROCESS FOR TREATING ALDEHYDES

1377806 Treating aldehyde-containing liquids and gases ASAHI KASEI KOGYO KK 25 Feb 1972 [27 Feb 1971 (2) 18 May 1971] 8816/72 Headings C1A and C1C A process for treating an aldehyde-containing liquid or gas comprises contacting it with at least one mole of a sulphite, or mixture of a sulphite and bisulphite, of alkali metal or ammonium for each mole of aldehyde at a pH of 6-11. The treated liquid may be subjected to an activated sludge treatment. The process may be countercurrent and may be operated at 20-70‹ C. The liquid may be a solution of aldehyde in water or alcohol. The sulphite and/or bisulphite may be used in aqueous solution or solid form. The aldehydes specified are formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, valeraldehyde, acrolein and crotonaldehyde. The pH may be controlled by use of bisulphites, hydrochloric, sulphuric, nitric, phosphoric, formic, acetic and butyric acids, phenol, cresol, sulphites, caustic soda and potassium calcium hydroxide, ammonia, ethylamine, butyl anine and pyridine. Other substances which may be present in the liquid or gas include carbonic, propionic and acrylic acids, methanol, nitrogen and butane.