| 摘要 |
1,140,588. Ethylene glycol. MITSUBISHI PETROCHEMICAL CO. Ltd. 12 Dec., 1966 [17 Dec., 1965], No. 55549/66. Heading C2C. Preparation of high purity ethylene glycol substantially free from aldehydes by subjecting crude ethylene glycol to distillation in the presence of a compound containing a phenolic hydroxy group as an antioxidant thereby repressing aldehyde forming reactions. The antioxidant, which should have a boiling point above that of ethylene glycol, is preferably present in an amount of 1 p.p.m. to 1% by weight of the ethylene glycol. Specified antioxidants include α-naphthol, #-naphthol and, in particular, p-aminophenol. Although ethylene glycol from any source may be used material obtained by the hydrolysis of ethylene oxide and containing specified amounts of glyoxol, acetaldehyde and formaldehyde is treated in the examples. |
