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Supercritical fluid extraction of jojoba oil from Simmondsia chinensis seeds using CO 2 as the solvent is presented in this study. The effects of process parameters such as pressure and temperature of extraction, particle size of jojoba seeds, flow rate of CO 2 , and concentration of entrainer (hexane) on the extraction yield were examined. Increases in the supercritical CO 2 flow rate, temperature, and pressure generally improved the performance. The extraction yield increased as the particle size decreased, indicating the importance of decreasing intraparticle diffusional resistance. The maximum extraction yield obtained was 50.6 wt% with a 0.23-mm particle size and a 2 mL/min CO 2 flow rate at 90°C and 600 bar. Use of an entrainer at a concentration of 5 vol% improved the yield to 52.2 wt% for the same particle size and also enabled the use of a relatively lower pressure and temperature, i.e., 300 bar and 70°C.The word "jojoba" refers both to the plant (Simmondsia chinensis) and to the extract of its seeds. The total oil content of mature jojoba seeds generally ranges from 50 to 54 wt%. The jojoba oil extracted from the seeds is not a TG, but a liquid wax (m.p. 7°C) composed mostly of esters of monounsaturated C 20 -C 22 FA (MUFA) and long-chain monounsaturated alcohols. Jojoba also contains trace quantities of palmitoleic acid, oleic acid, hexacosanol, alcohols of lower M.W., and α-, δ-, and γ-tocopherols. The oil can be isomerized, hydrogenated, sulfurized, chlorinated, or transesterified. Jojoba oil and its derivatives have a wide range of industrial uses, mainly in cosmetics, and are incorporated in formulations for skin-care preparations such as lotions, moisturizers, massage oils, and soothing creams. It is also widely used in hair-care products, such as shampoos, gels, and mousses, and is a very good base for cosmetics and nail products (1-7).Different methods, similar to those applied to other oilseeds, have been used to extract jojoba oil from the seeds. Those methods are mainly mechanical pressing, mechanical pressing followed by solvent extraction (leaching), or solvent extraction only (1,8).Abu-Arabi et al.(3) investigated the extraction of jojoba oil by pressing and solvent extraction. They investigated the effects of some organic solvents used in the leaching process, including hexane, petroleum ether, benzene, chloroform, isopropanol, toluene, carbon tetrachloride, tetrachloroethylene, and heptane, on extraction yield and found that the maximum yield of leached oil, achieved with hexane, was 52 wt%.The past 20 yr have witnessed an intense interest in the use of supercritical fluids (SCF) in separation science. Supercritical fluid extraction (SFE) is an alternative extraction method whereby SCF instead of organic solvents are used as extraction media. SFE and fractionation have been applied to natural materials to separate the desired components from solid/liquid matrices in the food, perfumery, cosmetics, and pharmaceutical industries. Most of the work has been devoted to determining the composi...

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A preliminary experimental study is described in which a low concentration of S02 (0.2% v/v) is removed from air at temperatures between 358 and 640 K by reaction with bauxite and red mud, which consist of several metal oxides in a lab-size fluidized bed reactor of 5-cm diameter. CuO on activated alumina, a well-known sorbent for S02, was also tested in the same system for comparison. A model based on the two-phase theory of fluidization was used to simulate the sorption process. It was shown that a kinetic rate expression for sorption of S02 on a single metal oxide to yield a metal sulfate can also be used for mixtures of metal oxides by defining an overall apparent rate coefficient and an overall consumption coefficient for active sites. The work indicated that bauxite and red mud could also be considered as potential sorbents like CuO for S02 sorption in a typical range of stack gas temperatures.