Chemistry of inorganic compounds – Extracting – leaching – or dissolving
Reexamination Certificate
1997-01-31
2001-05-01
Bos, Steven (Department: 1754)
Chemistry of inorganic compounds
Extracting, leaching, or dissolving
C426S428000, C426S429000, C426S430000, C554S008000, C554S009000, C554S013000, C554S014000, C131S298000
Reexamination Certificate
active
06224847
ABSTRACT:
The present invention relates to a solvent extraction process in which a raw material containing a particular compound or composition is treated with an extraction solvent so as to remove at least a proportion of that compound or composition from the raw material.
Processes for extracting a desired compound or composition from a raw or bulk material which contains that compound or composition as a constituent part using a suitable extraction solvent are known in the art. In these known processes, the raw material is contacted with the extraction solvent, often under vigorous mixing conditions so as to facilitate the dissolution of the desired compound or composition into the extraction solvent, and the resulting solvent liquor containing the desired compound or composition is then separated from the raw material for subsequent processing, e.g. distillation to remove the extraction solvent. Multiple extractions may suitably be carried out on the same raw material sample so as to maximise the amount of the desired compound or composition which is extracted from that sample. Typical examples of extraction solvents which have been used in the prior art extraction processes include hexane, methyl acetate, ethyl acetate, acetone and methanol.
Although solvent extraction processes are used on a commercial scale, the extraction solvents which are currently used in these processes are not wholly satisfactory. Thus, when solvents such as hexane are used to extract flavoured or aromatic oils, such as are used in the food and cosmetic industries, from plant matter containing those oils, unwanted materials contained in the plant, e.g. high molecular weight waxes, tend to be eluted along with the desired oil. This problem necessitates subjecting the resultant hexane liquor to further processing in which the unwanted waxes are removed by extraction, e.g. using ethanol. Furthermore, the extraction solvents which are currently in use have fairly high boiling points, and the elevated temperatures which are employed in the distillation process to remove these high boiling solvents from the extracted material can cause problems. For example, the flavoured or aromatic oils contained in certain plants are complex substances containing a large number of individual compounds some of which are relatively volatile or relatively thermally unstable. Consequently, high distillation temperatures can tend to result in a loss of product either through co-evaporation of the more volatile compounds with the extraction solvent or thermal degradation of the more thermally unstable compounds.
The present invention provides a new solvent extraction process which can be used to extract a wide variety of compounds or compositions from raw or bulk materials of which they form a constituent part. In one particular embodiment, the present invention provides a solvent extraction process which is capable of extracting the flavoured or aromatic oils contained in certain plant materials without eluting the high molecular weight waxes they contain.
According to the present invention there is provided a process for extracting a compound or composition of matter from a raw material containing that compound or composition as a constituent part, which process comprises the steps of (1) contacting a sample of the raw material with an extraction solvent comprising a C
1-4
(hydro)fluorocarbon and a co-solvent, and (2) separating the solvent liquor thus obtained containing the extract from the raw material.
In one particular embodiment, the extraction process of the present invention can be used to extract a natural product, such as a flavoured or aromatic oil, from a plant material containing that product.
Accordingly, the present invention provides a process for extracting a natural product from a plant material containing that product as a constituent part, which process comprises the steps of (1) contacting a sample of the plant material with an extraction solvent comprising a C
1-4
(hydro)fluorocarbon and a co-solvent, and (2) separating the solvent liquor thus obtained containing the extract from the plant material.
When used in this specification, the expression “plant material” not only includes materials which are essentially unprocessed and as such are clearly recognisable as being of plant origin, for example bark, leaves, flowers and seeds, but also materials, which although originating from plants, have been subjected to various processes and as such have a form which is somewhat different than the plants from which they originated, for example ground cumin and ground ginger.
In a further embodiment, the extraction process of the present invention can be used to extract a biologically active compound, such as a pesticide or a pharmaceutically active substance, or a precursor to such a compound from a raw material containing that compound or precursor, such as a plant material, a cell culture or a fermentation broth.
Accordingly, the present invention provides a process for extracting a composition comprising a biologically active compound or a precursor thereof from a raw material containing that composition as a constituent part, which process comprises the steps of (1) contacting a sample of the raw material with an extraction solvent comprising a C
1-4
(hydro)fluorocarbon, and (2) separating the solvent liquor thus obtained containing the extract from the raw material.
Suitable pesticides which may be extracted using the extraction process of the present invention include insecticides such as the pyrethroids.
Suitable pharmaceutically active substances which may be extracted using the extraction process of the present invention include the penicillins, the alkaloids, paclitaxel, monensin and cytochalasin. Precursors to these compounds may also be extracted using the extraction process of the present invention. In one particular application for the extraction process of the present invention, paclitaxel, which is an important anti-cancer drug, and/or taxane, which is a precursor to paclitaxel, can be extracted from yew tree products, such as the bark or needles harvested from these trees. When the extraction process is used to extract a biologically active compound or precursor thereof, the extraction solvent which is used will preferably comprise a co-solvent in addition to the C
1-4
(hydro)fluorocarbon.
According to a further aspect of the present invention, there is provided a composition comprising a pharmaceutically active substance obtained from a raw material product using the extraction process of the present invention.
According to a still further aspect of the present invention, there is provided a composition comprising a pharmaceutically active substance obtained from a raw material product using the extraction process of the present invention for use in medicine.
The present invention also provides a process for extracting a composition comprising one or more polar group containing compounds from a raw material containing that composition as a constituent part, such as a plant material, which process comprises the steps of (1) contacting a sample of the raw material with an extraction solvent comprising a C
1-4
(hydro)fluorocarbon and a co-solvent, and (2) separating the solvent liquor thus obtained containing the extract from the raw material.
The extraction solvent which is used in the process of the present invention comprises a C
1-4
(hydro)fluorocarbon (i.e. a (hydro)fluorocarbon having from 1 to 4 carbon atoms). Mixtures of two or more (hydro)fluorocarbons may be used if desired. By the term (hydro)fluorocarbon we mean a compound selected from the group consisting of the hydrofluorocarbons and the perfluorocarbons.
Although extraction solvents comprising a perfluorocarbon such as perfluoropropane may be usefully employed in the process of the present invention, the preferred extraction solvents will comprise one or more hydrofluorocarbons. Hydrofluorocarbons having from 1 to 3 carbon atoms, especially the hydrofluoromethanes, hydrofluoroethanes and hydrofluoropropanes, are more preferred, an
Noakes Timothy James
Powell Richard Llewellyn
Wilde Peter Frederick
Bos Steven
Cook Alex McFarron Manzo Cummings & Mehler, Ltd.
Imperial Chemical Industries plc
LandOfFree
Process for the extraction of a compound by a fluorocarbon... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for the extraction of a compound by a fluorocarbon..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for the extraction of a compound by a fluorocarbon... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2549939