US1877875A - Process for the extraction of valuable ingredients from heat sensitive raw materials - Google Patents

Description

Sept. 20, 1932. M. B. HOPKINS 1,877,875

PROCESS FOR THE EXTRACTION OF VALUABLE GREDIENTS FROI HEAT SENSITIVE RAW MATER'IA Filed July 29, 1929 I MAYHQN B.HOPK\N3 INVENTOR ATTORN EY Patented Sept .20, 1 932 vum'rao STATES PATENT orrlcr.

MARION E. HOPKINS, E ELIZABETH, NEW JERSEY, ASSIGNOB To STANDARD OIL DE- VELOPMENT COMPANY, A CORPORATION OF DELAWARE "rnocEss Eon THE EXTRACTION or VALUAIBLE INGREDIENTS rEom: HEAT SENSITWE RAW MATERIALS Application filed. July 29,

' The present invention relates to the art of obtaining concentrated extracts of materials sensitive to only slightl elevated temperatures, and more specifical y comprises an imcentrated extracts of pyrethrum flowers in kerosene, or other oils, and also to an improved apparatus for accomplishing this result. The invention will be fully understood from the following description and the drawing which illustrates one form of apparatus for carrying out the process. I

The drawing is a semi-diagrammatic view in sectional elevation of an apparatus constructed according to my invention and indicates the flow of material. I

Referring to the drawing, reference numerals l, 2 and 3, indicate extraction chambers which are filled with the material to be 29 extracted and which are to be used alternately, as will be described. The extract- .ing medium, a light hydrocarbon, such as butane, pentane or hexane, or a mixture of such hydrocarbons as petroleum ether, is

forced by pump 4 from source, not shown,

through a feed line 5 and into any one of the extraction chambers by valved branch lines 7, 8 or 9, respectively. The extracting medium flowing through the material to be ex tracted on coming in contact with that ma terial, dissolves the soluble ingredients. The liquid cntaining the dissolved ingredients is removed from the base of the chambers by valved lines 10, 11 or 12, respectively, to a manifold 13 which conducts the liquid to a still 14, preferably by way of tower 15 mounted on the still. The still which is used to vaporize the extracting medium from the extracted material and to dissolve the extracted material in another oil, such as kerosene is heated by a steam coil 16, or by other suitable means, and a regulated stream of kerosene, or other oil, with a boiling point higher than the extraction medium may be fed by line 17. Still 14 is maintained at a temperature above the vaporization temperature of the lighter oil sothat the lighter oil 1929. Serial No. 382,009.

movable heads, not shown in detail, for' charging and discharging, and valved branch pipes 20, 21- and 22, respectively, from a line 23, through which heated inert gas, such as nitrogen, carbon dioxide or steam may be forced to vaporize the light oil clinging to the spentraw material. The gas and vapor leave by valved vapor lines 24, 25 and 26 to a manifold 27 and cooler 28. Condensate can be removed from drum 29 and the'remaining vapor compressed for recovery of light oil by compresser 30, cooled by cooler 31- and collected in drum 32. The extracting medium such as butane, hexaneor petroleum ether, after dissolving the soluble ingredients of the material in chambers 1, 2 or 3, carries them to still 14 where the solvent or extracting medium is va orized and precipitates the soluble ingre i'ents in that still. The vapors are condensed in condenser 19 and are ready for use in another or the same extraction. The extracting medium by this process can be circulated until no more soluble ingredients are present in the material.

The extracted material, which in the case of the extraction of pyrethrum flowers is readily liquefied by heat at 5060 C. may be with-.

drawn from still 14 substantially free of light oil as the light oil is vaporized in still 14 and may be allowed to cool and harden, or it may be withdrawn in solution in light oil, or kerosene, or heavier oil depending upon what oil is used in still '14, but in any case it is desir able to conduct it by means of pipe 33 through pressure reduction valve .34 into a stripping still that may be in the form of a tower 35, heated by coil 36. -Light oil vapor is removed to condenser 37, trap 38 and vacuum pump 39, if it is desired to hold the tower under reduced pressure. Light oil is condensed in cooler 40 and collected in drum 41. This oil, along with that from drum 32 is taken to storage and by means of pump 4 may pyrethrum extract is. removed from still 35 by line 42 substantially free of light oil and is collected in storage (not shown). 7

In the operation of the present process it has often been found desirable to extract at temperatures below a certain point above which the valuable extractives are eithertotally destroyed or deteriorated. With pyrethrum the temperature should not rise above about 100 C. The three or more extraction chambers are alternately charged, extracted and discharged, so that the equipment, other than the chambers may be continuously in use.

The apparatus comprising the cycle of still 14, condenser 19 and the extraction chamber in use, is preferably maintained under pressure which may vary with the volatility of the solvent, but it should be above atmos pheric pressure and may be as high as 200 or even 500 pounds per square inch, andso as to allow condensation at ordinary cooling water temperature. As stated above, the temperature of still 14 should not rise above about 100 C. and this may be conveniently regulated by controlling pressure in the coil 1 The material to be extracted is charged to the extraction chambers 1, 2 and 3 in a finely ground or unground condition, which latter is preferable with pyrethrum flowers, and it is preferable to use to 1 gallon of light oil per pound of flowers to be extracted. When the flowers are totally extracted, or their valuable eontents is reduced to the economic limit for extraction, the chamber is cut out of the cycle by operation of suitable valves, after the chamber has been allowed to drain, and another chamber containing fresh flowers is substituted in the system. The spent chamber is then blown with hot inert gas or steam to drive the volatile solvent from the spent flowers and the vapors are condensed so that the recovered solvent may be reused and the flowers may be discharged withoutfire hazard. The chamber is then dumped, recharged, and in its turn is replaced in the extraction cycle.

When starting operations the still is filled with kerosene or other oil, which is to be used as the carrier for the extract, or with light oil if the extracted material is to be obtained free of solvent and heat is added to vaporize light oil and cause its circulation as disclosed. When the concentration in the kerosene is raised to the point desired, fresh kerosene may be added in regulated quantity by line 17, either intermittently or continuously, and oil may be withdrawn from still 14 and discharged with reduction of pressure into still 35 in which traces of low boiling so vent are removed, either under the influence of vacuum or steam, or their joint action, the unvaporized oil extract may be withdrawn from still 35, cooled and stored for use. The extraction medium added by line 4 is to make up losses and may be added either continuously or preferably at intervals and the oil from drums 32 and 41 may be reused, if desired.

The quantity of kerosene added may vary over wide limits, generally. less than 1 gallon per pound of flowers used and depends only on the desired strength of the concentrate, which may be thinned to any degree by addition of other oil, as will be understood. When applied to the extract of pyrethrum flowers, it is preferable to use a kerosene with an initial boiling point not below about 200 C. and end point not over about 280 C. as indicated by the ordinary analytical distillation. The extraction medium may be a mixture of light hydrocarbons such as petroleum ether, or a pure hydrocarbon such as hexane, pentane, butane or propane. It is preferable to use a mixture with an end point of not over about C. and not containing substantial quantities of hydrocarbons boiling below propane. Such an extraction medium is particularly advantageous for extraction of pyrethrum flowers, since it is cap able of removing the active insecticidal in,- gredients with a smaller proportion of inactive, darkly colored constituents than is possible with higher boiling solvent, such as kerosene or heavy naphtha.

It will be understood that when the extracted material is readily liquefiable by heat, such as the material extracted from pyrethrum flowers, kerosene or heavier oil need not be added to still 14, and the extracted material may be obtained as a soft resinous substance, substantially free of hydrocarbon oil. The substance, when melted, is not viscous or sticky and runs through the tower and pipes with ease.

The present invention,.while particularly adapted to the extractiofi of pyrethrum flowers, is not limited to that alone, as it may be used to extract any materials ,soluble in a hydrocarbon solvent, nor is it limited to any particular illustrative example of the apparatus or its operation. The invention is to be limited only to the following claims in which it is desired to claim all novelty inherent in the invention.

I claim:

1. Method of extracting insecticidal matter from pyrethrum flowers and the like, comprising the use of two solvents having different boiling points, first extracting the flowers under superatmospheric pressure with a lower boiling hydrocarbon solvent boiling below about 70 G., whereby insecticidal matter is dissolved, passing the resulting solution into a distillation zone in which the solution is mixed with a higher boiling solvent for the insecticidal matter, vaporizing the lower boiling solvent at a temperature below about 100 C, and withdrawing the remaining solution of insecticidal matter in the heavier solvent.

2. Method according to claim 1, in which the heavier solvent is an oil of the kerosene type and the solution of insecticidal matter in the heavier solvent has an initial boiling point above about 200 C.

3. Process of extracting organic material containing ingredients soluble in an aliphatic m hydrocarbon solvent and sensitive to only slightly elevated temperatures, comprising the extraction of the material with a low boiling aliphatic hydrocarbon solvent, commingling the solutlon thus'obtained with a higher boiling aliphatic hydrocarbon solvent adapted to dissolve the extracted compounds,

and removing the low boiling solvent.

MARION B. HOPKINS.

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