Firearms
Patent
1984-01-13
1987-10-06
Brown, Johnnie R.
Firearms
514 68, 424DIG8, A01N 6500
Patent
active
046982221
DESCRIPTION:
BRIEF SUMMARY
The present invention refers to an improvement in the extraction of insecticidal substances from plants by means of organic solvents.
The treatment by different organic solvents of plants which contain insecticidal substances has been the object of extensive work in the past; the only solvents which have given industrial results are chlorinated hydrocarbons, in particular methylene chloride and chloroform, which dissolve large quantities of insecticidal substances. Thus, one of the most important products, rotenone, is readily extracted, Cparticularly from derris, by means of said solvents, in which it is soluble in an amount of 58.2 g and 73.4 g respectively in 100 ml of solvent. However, it is not stable in such solutions and it is practically impossible to obtain it in pure form. Furthermore, while it is possible to effect an extraction with chlorinated solvents in a factory where all necessary health precautions are taken, the insecticide cannot be used in solution, in these unhealthy solvents, for the spraying of surfaces or objects infested by insects. The goal of extracting insecticides by means of an absolutely harmless solvent which makes it possible to obtain the insecticide in the desired state of purity is therefore still present.
The present invention fills this gap in the prior art. It makes it possible to extract the insecticidal materials contained in the plants by means of liquids which are entirely harmless, both to man and to animals. This new process also makes it possible to obtain the insecticide, and particularly rotenone, in highly concentrated state.
The invention is based on the unexpected finding that esters of aliphatic acids of sufficiently high molecular weight make it possible to dissolve the insecticidal substance, in particular rotenone.
This finding is all the more surprising since it has been known for a long time that fats, particularly cottonseed or olive oils, or otherwise stated glycerin esters of different fatty acids, are poor solvents for rotenone. It is therefore surprising to find that alkyl esters, for instance, the butyl, hexyl, and octyl esters, etc. of fatty acids such as lauric, oleic, or stearic acid, dissolve rotenone.
The process of the invention, which involves treating a dry plant containing an insecticide principle with an organic solvent so as to extract the insecticide and separating the resultant solution from the residues of the plant, is characterized by the fact that the solvent employed is an aliphatic ester containing at least 12 carbon atoms, preferably 18 to 36 carbon atoms.
The preferred solvents in accordance with the invention are alkyl or alkenyl esters having 1 to 16 carbon atoms of C.sub.6 to C.sub.30, or better C.sub.8 to C.sub.20, aliphatic acids.
Thus one can employ to advantage methyl, ethyl, propyl, isopropyl, butyl, amyl, hexyl, octyl, isooctyl, nonyl, lauryl and oleyl caprylates, caprates (decanoates), undecanoates, laurates, myristates, palmitates, oleates, ricinoleates, linoleates, linolenates, stearates, arachidates, lignoceates, cerotates, cetoleates, erucitates, etc., or the like.
The process of the invention can be carried out in different ways. One may use the above-defined ester to treat the dry power of the plant containing the insecticidal substance. However, as the esters in question are more or less viscous while the powdered mass to be treated is rather voluminous as compared with the amount of solvent used, the operation becomes easier if the extraction medium is diluted with a lighter solvent, in particular a chlorinated hydrocarbon.
Another, more advantageous method consists in effecting a first extraction in the conventional manner, using chlorinated solvents so as to obtain an enriched extract or what is ordinarily called a "resin", which may contain, for instance, about 40% rotenone, and then subjecting the latter to extraction with the esters according to the invention. In this way, one can obtain highly concentrated products, namely containing more than 90% rotenone or other insecticides.
The solvents of the
REFERENCES:
patent: 2149917 (1936-04-01), Kilgore
patent: 2267385 (1941-12-01), Whitmino
patent: 2374918 (1945-05-01), Brown
patent: 2428494 (1947-10-01), Jones et al.
Grinda Francoise
Gueyne Jean
Brown Johnnie R.
Rollins John W.
SAPHYR S.A.R.L.
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