CS232079B1 - A method for extracting cholesterol from lanolin hydrolysis products and apparatus for performing the method - Google Patents

Abstract

A method for extracting cholesterol from lanolin hydrolysis products, in which the hydrolysate is diluted with water and ethanol and extracted with a solvent, which may be paraffinic gasoline with a boiling point range of 80 to 200 °C, paraffinic hydrocarbons with 6 to 10 carbons, dichlorostane, trichloroethylene, tetrachloroethylene, tetrachloromethane or chloroform. The hydrolysate is diluted with water in a volume ratio of 1:1 to 1:3 and ethanol in a volume ratio of 1:0 to 1:1.5 and, using a vibrating motion, is dispersed into drops and brought into continuous countercurrent contact with the solvent, the volumetric flow rate ratio of the diluted hydrolysate and fresh solvent being 1:0.8 to 1:2 and the temperature being maintained in the range of 50 to 60 °C. The described method simplifies the production equipment, shortens the processing time and reduces the demands on the operator. In addition, it allows for automation of the entire process.

Description

The invention relates to a process for extracting cholesterol from lanolin hydrolysis products and to an apparatus for carrying out the process.

Lanolin, a waste product of wool washing, is a valuable raw material for obtaining substances such as cholesterol, higher alcohols and higher fatty acids. The first step in the separation and recovery of these substances is the hydrolysis of the esters and neutralization of the free fatty acids contained in lanolin. Upon hydrolysis with an alkaline lye, for example an aqueous alcoholic solution of potassium hydroxide, the free and bound acids in the lanolin contained in the respective alkali salts are converted. Cholesterol and other neutral substances can be obtained from the resulting mixture by extraction with a suitable organic solvent.

Separation of cholesterol from other substances contained in the extract can be accomplished in various ways. Most commonly, the method is based on the formation of a cholesterol addition compound with various organic or inorganic reagents such as oxalic acid (US Pat. 2,562,605), succinic acid (British Pat. 615,778), urea (US Pat. 2,559) 158), zinc chloride (Niewiadomski et al .: Przemysl Chemiczny 44, 215, 1965), calcium chloride (Chem. Abstr. 85 »P 80055» ibid. 81 P 96126), etc. Isolation of cholesterol from the lanolinal alcohol fraction by gradual crystallization has also been described. from one or more different solvents, or from one solvent at a certain temperature (U.S. Pat. No. 2,506,679).

645 227i ibid. 690 879 etc.), or separation of cholesterol from other components of the lanolin alcohol moiety by means of simplified chromatography on silica gel (European Pat. 55,415) »

Despite the separation of cholesterol from the extract, the yields and purity of the product are higher the higher the proportion of cholesterol in the solvent-free extract. In this respect, it is important that the extraction of cholesterol from the diluted hydrolyzate is as selective as possible

- 2 232 079 with respect to cholesterol, in order to retain as many other substances as possible in addition to the salts of organic acids and to extract preferably cholesterol.

Isolation of the cholesterol-containing lanolin-alcohol moiety after lanolin hydrolysis serves to separate the neutral lanolin fraction from the acid fraction. Various extraction solvents such as gasoline are used for this isolation (US Pat. 2,619,495; Neiwiadomski et al. Przemysl Chemiczny 44, 215, 1965; Barnes et al. Australian J. Applied Sci. 5, 88, 1952), benzene (Truters Manufacturing Chemist 1955, 551), hexane (Chem. Abstr. 89, 152705), acetone (US Pat.

579,986), ethanol (US Pat. 2,506,679), methanol (ibid), methyl ethyl ketone (ibid.), Dichloroethane (US Pat. 2,499,877), etc.

Some of these solvents have limited solubility for cholesterol (lower alcohols), are toxic (benzene), extract simultaneously many ballasts (acetone, methyl ethyl ketone, chlorinated hydrocarbons) or are relatively expensive (hexane).

A process has been proposed (Schwarz et al., PV 7910-82), wherein the lanolin alcohol portion is extracted by periodically repeated contacting with the extracting gasoline, whereby the hydrolyzed lanolin and gasoline are mixed ten times at a temperature of about 55 ° C, after which the combined gasoline extracts are distilled off. to dryness and the cholesterol is then isolated from the lanolinalcohol fraction thus obtained. The disadvantage of this process is primarily its lengthiness and the need for a relatively large amount of extraction solvent.

On a technological scale, this would mean complicated production equipment, requiring space, time and attendance, without the possibility of automating the entire process.

These drawbacks are overcome by the process of extracting cholesterol from the lanolin hydrolysis products of the invention. The principle of this process is that after the alkaline hydrolysis of lanolin, diluted with water and ethanol, the mixture is continuously brought into countercurrent contact with each other at elevated temperature and by vibration. A suitable solvent may be gasoline having a boiling range of 80 DEG to 200 DEG C., optionally paraffinic hydrocarbons having from 6 to 10 carbons and mixtures thereof, dichloroethane, trichlorethylene, tetrachlorethylene, carbon tetrachloride and chloroform, and mixtures of the solvents with ethanol.

Upon countercurrent contact of the diluted hydrolyzate with the solvent, the hydrolyzate is dispersed by means of a vibrational movement into droplets which advance upstream of the solvent and eventually settle continuously3

232 079 and clump together to form a continuous layer of cholesterol-free hydrolyzate. The hydrolyzate is diluted with water in a volume ratio of 1: 1 to 1: 3 and ethanol in a volume ratio of 1: 0 to 1: 1.5. Preferably, the diluted hydrolyzate is saturated with solvent prior to extraction. The ratio of the volume flow rate of the diluted hydrolyzate to the fresh solvent is 1: 0.8 to 1: 2. During contacting, the liquids are maintained at a temperature above 50 ° C, preferably in the range of 50 to 60 ° C.

The apparatus for carrying out the method according to the invention is a countercurrent extraction column with vibrating trays according to the invention no. 106 313, 132 022 and 139 895. This device is a highly efficient and powerful countercurrent extractor, but in the process of the present invention foam formation and entrainment of the hydrolyzate by the solvent occur. Surprisingly, this difficulty can be overcome by changes in its construction. The device according to the invention is characterized in that the set of perforated trays placed in their own column and oscillating vertically is made of polyfluoroethylene, polyethylene or polypropylene, i.e. materials poorly wetted with dilute hydrolyzate, which are resistant to solvents. Advantageously, the end of the column on which the diluted hydrolyzate feed is expanded such that its diameter is 1.5 to 3 times the diameter of the actual column, wherein a set of fixed perforated trays with 0.2 orifice holes is located between the actual column and the diluted hydrolyzate feed up to 1.0 cm and a specific open cross-section of 20 to 50%.

The process according to the invention makes it possible to largely eliminate the drawbacks of the prior art process and the device according to the invention positively changes the properties of the known vibrating tray extractor so that intensive continuous countercurrent contact of the dilute hydrolyzate and said solvents can be achieved. The continuous countercurrent contact of the diluted hydrolyzate with the solvent under the influence of a vibration motion results in a multiple reduction of the solvent to hydrolyzate ratio and thus the energy consumption for its regeneration. Furthermore, this results in a higher enrichment of the extract with cholesterol _f and thus an improvement in the process selectivity. Finally, the decrease in solvent consumption and process continualization greatly reduce the equipment volume required and thus the investment costs. Dilution of the hydrolyzate with water in a suitable ratio ensures that the resulting solution is only slightly miscible with the solvent, even at a low flow rate ratio of the two phases, while increasing the selectivity to cholesterol. Pre-saturation of the hydrolyzate with a solvent contributes to ensuring limited miscibility. By

232 079, that according to the invention the aqueous phase is dispersed in the organic phase, the phase separation after contact with each other is greatly facilitated. The addition of ethanol, either to the diluted hydrolyzate or to a fresh solvent, further contributes to accelerating the deposition. However, it also reduces selectivity and therefore, in order to perform the process optimally, the concentration of ethanol in the hydrolyzate needs to be kept within these limits.

It is known that the vibratory tray extractors of the above-mentioned U.S. Pat. The patents are able to induce very intense contact of the extracted phase with the solvent. However, the dispersion of the diluted hydrolyzate into said solvents leads to the wetting of the metal perforated floors with the hydrolyzate, resulting in a wide range of droplet sizes, which results in low volumetric performance and extractor efficiency. According to the invention, this deficiency has been overcome by the use of Teflon, polyethylene or polypropylene plates for the construction of perforated floors. A particular difficulty in countercurrently contacting the diluted hydrolyzate with a solvent in a vibratory tray column is the fact that the physical properties of both liquid phases vary greatly as the concentration of the extracted components changes, which again varies along the column. While in the vicinity of the hydrolyzate inlet the dispersion is formed almost spontaneously, an increased intensity of vibrational movement is required near the solvent inlet. Uneven dispersion formation then leads to a decrease in the volumetric performance and extraction efficiency of the apparatus. This drawback has been largely overcome by providing an expanded portion between the actual column and the hydrolyzate inlet equipped with stationary trays with openings whose diameter and total specific free area lie within the limits of the invention.

The device according to the invention is shown schematically in FIG. 1

Fig. 1 shows the case where the density of the diluted hydrolyzate is higher than the density of the solvent. In this case, a larger diameter cylinder 3 provided with stationary perforated trays 6 is located above the actual column 1 inside which the set of perforated trays 2 performing oscillating movement in the vertical direction is located. The dilute hydrolyzate inlet 4 is above the set of stationary trays and located above the level of hydrolyzate feed 4. Underneath the column 11 there is a settling space 7 into which the inlet of the fresh solvent 8 and the removal of the cholesterol-free hydrolyzate 9 flows. Under the inlet of the solvent 8 there is an interfacial interface 10 at which drops

232 079 cholesterol-free hydrolyzate settles and forms a continuous layer.

FIG. 2 shows the case where the density of the diluted hydrolyzate is lower than that of the solvent. The numbering of the individual parts is identical to that of FIG. 1. The stationary tray roller 3 is now below the lower end of the actual column 1 and the settling space 7 above the upper end. The position of the phase inlets and outlets is changed accordingly.

Examples 1 to 3 show the effect of the type of solvent, dilution with water and ethanol on cholesterol selectivity by shaking the diluted hydrolyzate with the solvent once. Examples 4 and 5 show the results of countercurrent extraction of the diluted hydrolyzate with gasoline on a vibratory tray extraction column.

Example 1

Hydrolysate obtained from 100 g technical lanolin, 15 g KOH,

3 cm of ethanol and 5 cm of water were diluted with water (1: 1 by volume) and shaken with gasoline (1: 1 by volume). After phase separation, the aqueous phase contained 5.38 wt%. and the organic phase 7.98 wt. cholesterol in dry matter.

Example 2

The hydrolyzate was diluted with water in a 1: 1 volume ratio and as in Example 1 was shaken with trichlorethylene in a 1: 1 volume ratio. After separation, the aqueous phase contained 4.72% and organic 9.42% cholesterol in the dry matter.

Example 3

The hydrolyzate as in Example 1 was diluted with water and ethanol in a ratio of 1: 0.5: 0.5 and shaken with petrol in a 1: 1 volume ratio. After separation, the aqueous phase contained 5.72% and organic 6.68% cholesterol in the dry matter.

Example 4

The hydrolyzate as in Example 1 was diluted with water and ethanol and pre-saturated with gasoline to contain 26 wt. of the original hydrolyzate, 36% water, 22% ethanol and 16% gasoline and was extracted in a countercurrent extraction column with vibrating gasoline trays at a 1: 1.2 dilution hydrolyzate / solvent flow rate. The column had an internal diameter of 50 mm and a length of 4 m and was not fitted with a cylinder of 232 079

- 6 cem with fixed floors. The amplitude of the plate oscillations was 0.2 cm, at a frequency of 0.84 Hz. The hydrolyzate feed contained 15 wt%, the extract 28 wt%. and the extracted hydrolyzate 3.2 wt. cholesterol in dry matter.

Example 5

The hydrolyzate as in Example 1 was diluted to contain 21 wt. of the original hydrolyzate, 48% water, 19% ethanol and 12% gasoline and was extracted in the same column as in Example 4 but shortened to 3.5 m and fitted with a cylinder having an inner diameter of 100 mm and a height of 50 mm , which contained 10 fixed floors with a hole diameter of 0.8 cm and a specific open area of 50%. Petrol extraction with 10% v / v ethanol was performed with a 1: 1.5 dilute hydrolyzate to solvent volume flow rate. The extract contained 43.4 wt. and raffinate 1.3 wt. cholesterol in dry matter.

Claims (4)

SUBJECT OF THE INVENTION 232 079 Process for extracting cholesterol from lanolin hydrolysis products, wherein the hydrolyzate is diluted with water and ethanol and extracted with a solvent which may be a paraffinic gasoline having a boiling range of 80 to 200 ° C, paraffinic hydrocarbons of 6 to 10 carbons, dichloroethane, trichlorethylene, tetrachlorethylene , carbon tetrachloride or chloroform, characterized in that the hydrolyzate is diluted with water in a volume ratio of 1: 1 to 1: 3 and ethanol in a volume ratio of 1: 0 to 1: 1.5 and dispersed into drops by means of vibrational movement and continuous countercurrent contact with the solvent, wherein the ratio of the volume flow rates of the diluted hydrolyzate to the fresh solvent is 1: 0.8 to 1: 2 and the temperature is maintained in the range of 50 to 60 ° C. 2 »process according to claim l _F wherein the diluted hydrolyzate is saturated prior to solvent extraction. 3. Apparatus for carrying out the method according to claim 1 comprising a vertical column having a settling space with a dilute hydrolyzate inlet and an extract outlet at one end thereof and a settling space (5) with a fresh solvent inlet and a dehydrated hydrolyzate inlet at the other end cholesterol, wherein in the case of a solvent with a lower density than the diluted hydrolyzate, the sedimentation space is above the upper end of the column and below the lower end, in the case of a solvent with a higher density than the diluted hydrolyzate the sedimentation space is below the lower end and within which a set of punched trays for oscillating movement in a vertical direction is located, characterized in that the diameter of the settling space (3) is equal to 1.5 to 3 times the diameter of the actual column (1), located therein, between the end of the column (1) and the supply from eděného hydrolyzate (4) set nehkybných perforated plates (6) with holes of diameter 0.2 to 1.0 cm and a measuring free cross section of the holes 20 to 50% · 4. Apparatus according to claim 3, characterized in that the trays (2) are made of polyfluoroethylene, polyethylene or polypropylene.