Chemical Engineering, Ben Gurion University of the Negev, Beer-Sheva, Israel. He received his B.Sc. degree from Universidad Catolica, Chile, in 1957 and a Ph.D. degree from Purdue University in 1960. His research interests are in the areas of fats and oils, artificial sweeteners, and thermodynamics. Hanoch Benajahu is a chemical engineer working for the Phosphates of the m JL, & Negev Company in Oron, : ifctsr-Jr Israel, He received his HMk-..-' B.Sc. and M.Sc. degrees j from Ben Gurion Universiy Wty of the Negev. He is also working part-time in projects related to the Industrial development of jojoba products.

Jojoba oil (Simmondsia chinensis) has been sulfur-brominated with sulfur monobromide in order to study the kinetics and parameters of the reaction and the mechanical properties of the product. Reaction runs were conducted in the range 1.1-8% S and 3.6-20.9% Br under different modes of operation. The reaction takes place by straight addition of the sulfur halide to the double bond. The decrease with time of the number of double bonds in solvents with different dielectric constant follows first-order kinetics. Mechanical testing of sulfur-brominated derivatives indicates that the product has superior properties as a lubrication additive, particularly for extreme pressure (Four-Ball weld point) load carrying applications.This work was undertaken as a continuation of our program on lubricant additives based on jojoba oil, a potential substitute of sperm whale oil. The wax produced from sperm whales has been used in various lubricant applications such as automotive transmission fluids, metal-working lubricants, industrial and automotive gear lubricants, and tractor hydraulic fluids. Inclusion of several whale species in the list of endangered species in 1970 has prompted the search for natural or synthetic substitutes. Many synthetic compositions have already appeared in the market that match or surpass sperm oil in some laboratory tests but not all in one product or from the same source.Several publications have shown that derivatives based on the oil extracted from jojoba nuts (Simmondsia chinensis) exhibit lubricating properties suitable for use as a substitute for sperm oil additives and for a variety of other applications involving polishes, waxes, coatings, and pharmaceuticals (Gieser et al., 1975; National Academy of Sciences, 1977;Wisniak, 1977).Jojoba is an evergreen bush of the Buxaceae family that grows in semidesertic areas and yields a nut that contains about 50% of an oil composed mainly of monoesters of the Czo and Czz alcohols and acids, with two double bonds. Details of the economic potential and chemical properties and technology have been recently summarized (National Academy of Sciences, 1977;Wisniak, 1977).Conventional extreme-pressure (E.P.) additives based on sperm whale oil include sulfurized sperm oils containing 10, 12, and 18% S, sulfur-chlorinated products with 6% and 8% each of sulfur and chlorine, and a chlorinated sperm oil having 32% chlorine (Thompson, 1972). Sulfur-chlorinated sperm oil gives better metal wetting and solubility properties than with other similarly sulfurchlorinated fatty materials. Chlorinated sperm oil is a highly polar compound with good metal wetting properties and provides higher E.P. activity at low concentrations than chlorinated paraffins.Organosulfur compounds and sulfur-halogenated compounds have been used as additives in lubricants for many years. Several studies have appeared on the effect of the chemical structure of these additives on their load-carrying performance under mixed lubrication and E.P. lubrication conditions (Allum and Forbes, 1968;Mould et ...

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