to 3 equivalents preferably 1 5 to 2 equivalents of hexamethylenetetramine in glacial acetic acid the mixture is heated for a period of 1 to 5 hours the reaction temperature is in the range of 100 u00b0 to 130 u00b0 c preferably about 130 u00b0 c and the reaction time is preferably 2 to 3 hours the concentration of 2 4 di tert butylphenol in acetic acid is in the range of 0 5 to 2m preferably about 2 0m after reaction of the 2 4 di tert butylphenol and hexamethylenetetramine in glacial acetic acid the reaction mixture is quenched with water or aqueous acid preferably with an aqueous acid in an amount roughly equal to that of the volume of acetic acid used the aqueous mixture is then further heated at reflux bath temperature about 130 u00b0 c for a short period of time preferably 0 5 to 1 hour after the treatment with aqueous acid or water the reaction solution is concentrated under vacuum to recover acetic acid or it is simply cooled and extracted with a non polar solvent preferred solvents for the extraction are hydrocarbon solvents such as hexane heptane toluene and xylene or ethers such as diethyl ether and tert butyl methyl ether the crude reaction product is further purified by passing the solution in the non polar solvent such as hexane or toluene through a pad of.