Rf Limonene

They conlalu about 8S per cent, of W-a-pincno, d jior ceui. ol rf-limonene, and 2 per nonl. of an alcohol. Small amounts of carronc, and of a efi-quitcrpeiie, which Is probably cyprcsscue, are also present. 

Tho known constituents of ginger grass oil are the terpenes, diuen-tane, d-a-phellandreoo and rf-limonene, together with geraniol, ana an alonboJ which is identical with that obtained by the reduction of porUlio aldehyde, and which is known as perillic alcohol. 

In addition to chemical assays, Basic Protocols 4 through 6 evaluate the physical properties of citms oils. These methods are based on the high percentage of rf-limonene, in which citms oils have characteristic values. Table Gl.5.7 provides the physical and chemical properties defined by Food Chemical Codex (NRC, 1981). 

The degree of chemical and optical purities of limonenes, again, depends on the exact source of the oil. Bulk rf-limonene currently available in the United States has optical purities in the range... 

Polyterpene resins are related to the oldest reported polymerization, as they were first observed in 1789 by Bishop Watson by treatment of turpentine with sulfuric acid [92]. Commercial polyterpene resins are synthesized by cationic polymerization of /3- and a-pinenes extracted from turpentine, of rf,/-limonene (dipentene) derived from kraft-paper manufacture, and of d-limonene extracted from citrus peels as a by-product of juice industry [1,80,82,93]. The batch or continuous processes are similar for the three monomers. The solution polymerization is generally performed in mixed xylenes or high boiling aromatic solvent, at 30-55° C, with AlCl3-adventi-tious water initiation. The purified feedstream (72-95% purity, depending on monomer) is mixed in the reactor with solvent and powdered A1C13 (2—4 wt% with respect to monomer), and then stirred for 30-60 min. After completion of the reaction, the catalyst is deactivated by hydrolysis, and evolved HC1 is eliminated by alkaline aqueous washes. The organic solution is then dried, and the solvent is separated from the resin by distillation. 

Massaldi, H.A., King, C.J. (1973) Simple technique to determine solubihties of sparingly soluble organics Solubility and activity coefficients of rf-limonene, -butylbenzene, and -hexyl acetate in water and sucrose solutions. J. Chem. Eng. Data 18,393-397. 

The most widespread use of limonene has been as a raw material for the manufacture of adhesives, such as the glue on labels and envelopes. Terpene monomers used for resin production are pinene, dipentene from turpentine and rf-limonene. Waterless hand cleaners produced from d-limonene were among the first to replace solvents such as mineral spirits. Although ri-limoncnc is more expensive than mineral spirits and kerosene, the former is used because of the pleasant citrus aroma and its claimed biodegradability (Coleman, 1975 Kutty et al., 1994). Many flavor chemicals... 

Essential oils or ti-limonene are recovered from oil-water emulsions by steam distillation at a reduced temperature. This is not a typical fractional distillation, as practiced when distilling cold-pressed oil, but rather, it is a bulk separation of the volatile compounds in the condensed vapor. When this distillation is applied to pure ti-limonene, the mass ratio of water d-limonene at atmospheric pressure is in the range of 8-10 1. In the actual oil emulsions, considerably more water must be distilled to recover a given quantity of rf-limonene, because this component is adsorbed by the pulp particles in the emulsion. If the distillation is performed in a continuous manner under pressure, the ratio of water removed per amount of (i-limoncne recovered can be reduced to 3 4 1 (Braddock, 1999). However, when the steam temperature rises above 120°C, recovery of d-limonene decreases due to formation of some water-soluble alcohols and epoxides, which are soluble in the aqueous phase and are not recovered in the d-limonene phase above the condensate. 

The monoterpene rf-limonene, widely used as a flavor and fragrant agent, is in the list of substances generally recognized as safe (GRAS) in food by the Food and Drug Administration (21 CFR 182.60 in the Code of Federal Regulations). However, recently, rf-limonene has been shown to cause some toxicity effects (Table 5.13). 

Kawamori, T., Tanaka, T., Hirose, Y., Ohnishi, M. and Mori, H. 1996. Inhibitory effects of rf-limonene on the development of colonic aberrant crypt foci induced by azoxymethane in F344 rats. Carcinogenesis. 17(2) 369—372. 

Okabe, H., Suzuki, E., Sayito, T., Takayama, K. and Nagai, T. 1994. Development of novel transdermal system containing rf-limonene and ethanol as absorption enhancers. J. Control Rel., 32 243-247. 

Schenk, J., Dobronte, Z., Koch, H. and Stolte, M. 1980. Studies on tissue compatibility of rf-limonene as a dissolving agent of cholesterol gallstones. Z. Gastroenterol. 18(7) 389-394. 

Wattenberg, L.W. and Coccia, J.B. 1991. Inhibition of 4-(methylnitrosamino)-l-(3-pyridyl)-l-butanone carcinogenesis in mice by rf-limonene and citrus fruit oils. Carcinogenesis. 1(12) 115—117. 

Properties Yellowish liquid. D 0.900-0.910. Insoluble in water soluble in alcohol. The oil obtained from the caraway seed. The chief components are carvone and rf-limonene. 

Ohara, N., Takayama, K., and Nagai, T. (1995). Combined effect of rf-limonene pretreatment and temperature on the rat skin permeation of lipophilic and hydrophilic drugs, Biol Pharm. Bull, 18 439-442. 

The containers were also tested for absorption and permeation of rf-limonene, a stimulant for fiavor. The results showed that the LCP-PET multilayer container retained more than five times the amount of d-Umonene as the PET container. Furthermore, tests on LCP and PET film show that the absorption of d-limonene... 

Chang, Y.-C. et al., 1997. Allergic contact dermatitis from oxidised rf-limonene. Contact Dermatitis. 37 308-309. 

Karlberg, A.-T. and A. Dooms-Goossens, 1992. Contact allergy to oxidized rf-limonene among dermatitis... 

The principal constituent of this oil is rf-limonene. Dipentene is also present. Methyl anthranilate and methyl methyl-anthranilate are also present, and traces of an unknown aldehyde. 

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