| abstract |
A mixture containing phenothiazines which is obtainable by reacting a mixture of diphenylamines comprising -1 to 5% by weight a) diphenylamine -of -8 to 18% by b) 4-tert-butyldiphenylamine -weight of -21 to 31% by c) one or more compounds selected from -weight of i) 4-tert-octyldiphenylamine - ii) 4,4'-di-tert-butyldiphenylamine - iii) 2,4,4'-tris-tert-butyldiphenylamine -20 to 31% by d) one or more compounds selected from -weight of i) 4-tert-butyl-4'-tert-octyldiphenylamine - ii) 2,2'- or 2,4'-di-tert-octyldiphenylamine - iii) 2,4-di-tert-butyl-4'-tert-octyldiphenylamine, -and -15 to 29% by e) the compound -weight of i) 4,4'-di-tert-octyldiphenylamine, or - the compounds - i) 4,4'-di-tert-octyldiphenylamine and - ii) 2,4-di-tert-octyl-4'-tert-butyldiphenylamine, - with 1 to 200 mol % of elemental sulfur, in the presence of 0.25 to 5 mol % of a condensation catalyst selected from the group consisting of iodine, aluminum bromide, aluminum chloride, iron(III) chloride, antimony chloride, copper iodide or sulfur iodide, in the temperature range from 80 DEG to 250 DEG C. The mixture containing phenothiazines finds utility as antioxidant in organic materials which are subject to degradation induced by oxidation, heat or exposure to actinic light, especially in lubricants and hydraulic fluids. |