GB861201A - Process for manufacturing terpeneless essential oils - Google Patents

Abstract

Terpenes are removed from essential oils by contacting the oils with a solid absorbent material in the form of particles or of pieces of porous, perforated or spongy structure having intercommunicating voids or passageways and which has a greater affinity for the terpenes than for the other odoriferous constituents of the oil. The absorbents used are non-polar, and preferably polymeric. Examples are rubbers, e.g. processed natural rubber, "Buna" S ("Buna" is a Registered Trade Mark), neoprene and silicone rubbers, and plastics, e.g. polyvinyl chloride, polyvinylidene chloride, polyalkylenes such as polyethylene, polystyrene and polyesters. They are preferably ground to a size of 0.001-0.1 inches or used in the form of a sponge. The oil may be diluted with a polar solvent, e.g. a C1-C6 aliphatic alcohol which may be mixed with a C1-C6 ketone or ether, chlorinated hydrocarbon, aromatic ether or lower ester. Up to 5% of water may be added to increase the polarity of the diluent. The absorbent is preferably wetted with a polar solvent and any air or other gas displaced from its surface. A fractional separation of the oil constituents may be made by passing the diluted oil through a column of absorbent and passing the effluent through a continuously recording refractometer (or an ultra-violet or infra-red spectrometer). Any absorbed oxygenated constituents of the oil may be eluted with a polar solvent and the terpenes may subsequently be eluted with a less polar solvent. Oils of high terpene content may be pretreated to reduce the terpene content by a conventional process such as distillation or solvent extraction. Oils mentioned are citrus oils (lemon, grapefruit, orange, lime and mandarin) petitgrain, bergamot, lavender, pimenta berry, leaf stem and bud clove oils, bay leaf, and geranium. Specified terpenes are the pinenes, myrcene, dipentene, ocimene, terpinolene, d-limonene, gamma-terpinene, phellandrene, thujene, sesquicitronellene, bisabolene, beta-caryophyllene and cadinene. In an example, gum rubber is used to separate South American oil of petitgrain into four main fractions linalool, linalool acetate, terpenes and other hydrocarbons, and ocimene. The process may also be used to segregate the various oxygenated constituents of the oils and also to segregate various terpenes, e.g. d-limonene and alpha-pinene from para-cymene.ALSO:Terpenes are removed from essential oils by contacting the oils with a solid absorbent material, in the form of particles or of pieces of porous, perforated or spongy structure having intercommunicating voids or passageways, and which material has a greater affinity for the terpenes than for the other odoriferous constituents of the oil. The absorbents used are non-polar, and preferably polymeric. Examples are rubbers, e.g. processed natural rubber, "Buna" S ("Buna" is a Registered Trade Mark), neoprene or silicone rubbers, and plastics, e.g. polyvinyl chloride, polyvinylidene chloride, polyalkylenes such as polyethylene or polystyrene, and polyesters. They are preferably ground to a size of 0.001-0.1 inches or used in the form of a p sponge. The oil may be diluted with a polar solvent, e.g. a C1-C6 aliphatic alcohol, which may be mixed with a C1-C6 ketone or ether, chlorinated hydrocarbon, aromatic ether or lower ester. Up to 5% of water may be added to increase the polarity of the diluent. The absorbent is preferably wetted with a polar solvent and any air or other gas displaced from its surface. A fractional separation of the oil constituents may be made by passing the diluted oil through a column of absorbent and passing the effluent through a continuously recording refractometer (or an ultraviolet or infra-red spectrometer). Any absorbed oxygenated constituents of the oil may be eluted with a polar solvent and the terpenes may subsequently be eluted with a less polar solvent. Oils of high terpene content may be pretreated to reduce the terpene content by a conventional process such as distillation or solvent extraction. Oils mentioned are citrus oils (lemon, grapefruit, orange, lime and mandarin), petitgrain, bergamot, lavender, pimenta berry, leaf, stem and bud clove oils, bay leaf, and geranium. Specified terpenes are the pinenes, myrcene, dipentene, ocimene, terpinolene, d-limonene, gammaterpinene, phellandrene, thujene, sesquicitronellene, bisabolene, beta-caryophyllene and cadinene. In an example, gum rubber is used to separate South American oil of petitgrain into four main fractions comprising respectively linalool, linalool acetate, terpenes and other hydrocarbons, and ocimene. The process may also be used to segregate the various oxygenated constituents of the oils and also to segregate various terpenes, e.g. d-limonene and alphapinene from para-cymene.