Autoxidation, and its Inhibition, in Anhydrous Lanolin

Long-term storage tests under good and bad conditions, and accelerated active oxygen method tests, have shown that autoxidative degradation of anhydrous lanolin can be satisfactorily inhibited for at least 32 months under good conditions or 2 years under bad conditions by 100 p.p.m. of butylated hydroxytoluene or butylated hydroxyanisole. Good results from other antoxidants, and disadvantages of some, are reported. Different lanolins are affected to different degrees, possible reasons being suggested, but autoxidation when uninhibited does not penetrate deeper than 1 cm. even after 2 years of adverse conditions; there is a fall in melting point and formation of up to 4.7 per cent of water-soluble substances including low-molecular weight acids. Absence of change in iodine value and rapid increase of acidity in darkness are contrary to previous reports.