ANHYDROUS
LANOLIN AND ITS SEPARATION
CRUDE WOOL GRE~SE
Indian
S. K. Ghosh and B. S. Rawat
Institute of Petroleum, Debra
FROM
Dun
A review has been presented
on the extraction of anhydrous
lanolin
from crude
wool
grease, its properties and uses. A method developed in this laboratory
uses a single selective
adsorbent
and a single Hydrocarbon
Solvent
under
controlled
conditions
of temperature,
aging time and adsorbent-crude
wool grease
ratio etc. All the undesirable
constituents
from
wool grease are removed in the process, which
yields better lanolin than superfine (B.P., U.S.P.);
grade with respect to colour, odour, acid value
and saponification
number etc. Yields are almost
quantitative.
Introduction
Refining of Crude Wool Grease
Various methods have been described for the
The term wood grease and wool wax (sometimes
called wool fat or degras) are generally used interextraction of pure lanolin from crude wool grease.
changeably for a complex mixture of water insolu- A few of the important ones have been summarized
ble materials secreted by the sebaceous glands of as below:
the skin of sheep, which permeates the entire fleece.
(1) According to Isabella et 1,1.13,
wool-fat is first
This also contains suint, the water soluble materials
adsorbed on a suspension of calcium sulphate which
(mostly organic in nature) secreted by another set is then separated by filtration and dried in darkness
of glands in the sheep's skin. Wool contains along at 50°C. The lanolin adsorbed is eluted with benzene
with these varying quantities of moisture, dirt etc. and passed through an alumina. column to remove
depending on the environment in which the sheep free fatty acids, soaps and salts etc. The solution is
live. All these materials (which may be called evaporated to remove lanolin.
crude wool grease) are removed by processes e.g.
(2) M. Kh. Gluzman et al4, in their method of
scouring with soaps and soda ash, or scouring with
separation
of lanolin from wool fat, have treated
solvents etc. from the wool fibres before they go for
wool fat with Bertholet salt and sulphuric acid to
spinning. Suint mayor may not be present with
separate crude lanolin, which is then treated with
crude wool grease depending upon the method of 0.5%
calcined soda and boiled in 1% 8ulphuric acid
scouring.
solution and centrifuged. The free fatty acids are
This crude wool grease must be refined before it neutralised with 2.0 - 5.0% caustic soda solution and
can be used for pharmaceutical and cosmetic pur- dry calcined soda. Finally, lanolin is recovered by
poses and, even for less critical uses, it is to be freed washing the resulting mass to make it free from
from objectionable odour and suspended impurities.
soaps and then by treatment with infusorial earth.
The refined wool grease is generally known either as
A new method of separation of lanolin from
lanolin, wool wax or 'wool fat'. The chemical comwool fat described by T.P. Zhuze et al.5, involves the
position of lanolin is described by many workers but contacting of l1quified petroleum gases (C3 Hs- C3 H6
still a great deal remains to be learned. It contains
mixtJ and woo~ fat in the ratio of 7:1 (by wtJ at
aproximately 70% non-acidic or unsaponifiable frac100-135 atmospheric pressure and 100°C. The matetion2 and 30% acid fraction1 but does not contain
rials separated are impurities which are used in the
any glycerol or triglycerides. The acid fraction con- manufacture of lubricants. The pressure is released
sisting of high molecular-weight fatty acids and
to 40-50 atmospheres when refined lanolin is separated
hydroxy fatty acids is esterified with non-acidic
out, which is then decolourised. The gases are re[,raction consisting of high molecular-weight alcocycled.
hols e.g. aliphatic monohydric alcohols 00-15%),
(4) Silica gel and an aluminosilicate catalyst
aliphatic diols (5%), sterols (35-40%) chiefly cholesterol, triterpenoid sterols (25-30%) chiefly lano.. were used separately as adsorbents for separation
sterol and about 15-25% of material which has never of lanolin from wool grease by I.L. Gurevich et a16.
been isolated or identified. The exact nature of The minimum adsorbent grease ratio was 1.6:1 at
60-70°0. The wool grease was dissolved in gasoline
these esters has not yet been satisfactorily deterin the ratio 1:0.6. On silica gel two portions were semined.
59
PETROLEUM
& HYDROCARBONS,
parated;
one black (0.5 - 1(70) and the other, the
lanolin of light colour. On alumino-silicate
only
lanolin was separated.
The adsorbent
was regenerated by washing
with an ethyl alcohol-benzene
moisture at 50-60°C and dried in a stream of inert
gas at 120-130°C.
(5) In the method described by E. Snyder', the
free fatty acids present in crude wool grease are
removed by taking the crude grease in water and
emulsifying
with soap, followed by treating
the
emulsion
with some alkali silicate
and
hydrogen
peroxide.
The resultant
grease is mixed with sulfonated castor oil when two layers are formed. The
upper layer is taken
out and washed with hot
water to give U.S.P. grade lanolin. This product is
passed on to a centrifugal
separator
to produce
anhydrous lanolin.
When cosmetics
grade lanolin
is desired, the
above-mentioned
dry product
is bleached
with
bleaching earth and then filter-pressed.
(6) Another method9 consists of treating
wool
fat that has been heated to 85°C with 0.25% by
volume of the salt of an acid, such as oxalic acid
or phosphoric acid, to precipitate
calcium and magnesium compounds and to reduce the ash content
after separation of the fat by centrifugation.
Then
30 per cent hydrogen peroxide in an amount of 1% by
volume is added to bleach the fat and improve the
colour. The bleached fat is neutralized
by sodium
hydroxide.
The fat is separated
from added products and impurities before being washed in a centrifuge.
Isopropyl
alcohol is added
to the wash
water to prevent emulsification.
The lanolin (refined wool fat) is dried. Bleaching is performed in
strong mineral acid to prevent excessive rapid decomposition
of hydrogen
peroxide. The lanolin is
bleached in both acid and alkaline medIum, which
results in a marked improvement in colour over the
bleaching of lanolin performed only after the neutralization and prevents increased acidity of the
lanolin.
Table
Anhydrous
Properties
1.
2.
3.
4.
5.
6.
7.
8.
9.
Sulphated ash
Volatiles (1 hr. at 105°)
Chlorides
Acid Value
Saponification value
Iodine Value
Melting Point
Penetration value, unworked
Colour, Lovibond (.1" cell, molten)
Lanolin
VOL. 4, NO. 2, JULY 1969
(7) Method
follows:1o
authors
is as
The process consists of selective adsorption, extraction, filtration followed by recovery of solvent
by distillation. Crude wool grease is contacted with
a suitable adsorbent in the ratio of 1 : 2 approximately at 50-55°C and the mixture thus obtained is
aged for few hours at this temperature before subjecting the same to extraction with an aromaticrich solvent at room temperature followed by filtration and removal of the solvent by vacuum distillation.
In this process the colour and odour of lanolin
are improved by use of this single adsorbent
due
to its bleaching
and decolourizing
properties.
The
suspended
impurities
and other undesirable
constituents present in wool grease are also removed. The
acidity and nitrogenous
constituents
(if any) are
eliminated
by adsorption.
Other inorganic
impurities which may escape adsorption are left behind by
the non-polar
solvent extracting
only the lanolin
part out of the adsorbent-wool
grease complex.
This method gives quantitative
yield. In addition, it
is quite flexible with respect to the methods of
scouring
as the naturally
occurring
impurities
associated
with scoured wool grease obtained
by
both the methods are similar in nature. The adsorbent to wool grease ratio can be fixed depending on
the colour requirement
(Fig. 1). The analysis of the
product obtainedlO as seen from Table 1, indicates that
the quality better than superfine grade may be obtained.
1
B.P., U.S.P., etc.
Superfine
Grade
trace
trace
trace
0-0,06%
trace
trace
0.1-0.5%
92-106
18-32
34-40°C
160-180
3-4.5 units
yellow
0.3-0.5
units
red
60
developed by the
I
Grade
2
0-0.06%
trace
trace
0.1-0.5% 0.1-0.5%
92-106
92-106
18-32
18-32
34-40°C
34-40°C
160-180
160-180
6.5-8 units13-15 units
yellow
0.6-0.8
units
red
yellow
1.3-1.5
units
red
Product
obtained
by authors
trace
trace
trace
0.1-0.15%
98-104
26-29
34-40.C
200-230
2-3.5 units
yellow
0.2-0.4
units
red
GHOSH & RAWAT:
ANHYBROUS
LANOLIN AND ITS SEPARATION
The various properties of anhydrous lanolin thus
obtainedlo were determined under identical conditions and are compared with B.P., U.S.P. etc. Specifications in Table 1.
Uses: Lalolin has its wide applications in the
field of industry, pharmaceuticals
and cosmetics.
The Table-2 given below highlights the uses of lanolin in U.S. in 19528.
Table 2
Uses of Wool Grease
Metal lubricants
Cosmetics
1ust Preventive
Lube on additives
Military foot wear
% by wt.
23.1
13.2
9.85
6.6
4.95
Leather
Driving
Pharmaceuticals
Fur dressing
2.65
4.55
4.0
2.65
belts
Medical
Adhesive tapes
Industrial
Ropes
Soap
Printing inks
PaInts
Miscellaneous
Total
0.75
2.35
1.6
0.75
0.75
22.35
FROM CRUDE WOOL GREASE
2'8
2'4
LIJ
U)
<(
LIJ
a:
(!)
I
..J
0
0
3:
0
...
2'0
.6
'2
...
z
LIJ
In
a:
0 0,8
U)
0
<{
IL.
0
0 0'4
f=
<(
a:
to'
3:
0
0
10
20
30
LOVIBOND COLOUR
Fig. 1.-Lovibond
100.00
4.
Acknowledgement
The authors are grateful to Doon Valley Wool
5.
Combers, Dehra Dun, for initiating and supplying
the necessary sample of crude wool grease required
for the investigation. They are also thankful to
6.
Dr. 1. B Gulati for the valuable suggestions he gave
from time to time, and Mr. A. N. Mathur for his help
in the experimental work.
7.
8.
References
1. Weitkamp,A.W.,J. Am. Chern. Soc. 67, 447-54,(1945). 9.
2. Velluz,L., and Leduer, E; Bull Soc. Chern. bioI.; 27
211-18(1945).Chern. Abstr. 40, 48979 (1946).
10.
3. Isabella Harati, Rose Thea Schip, and Eugenia Leonte,
colour vs. weight
to wool grease.
40
50
60
~
ratio of adsorbent
Rev. Chim. (Bucharest), 8, 703-9 (1957). Chem. Abstr.,
52 10610f (1958).
Gluzman M. Kh., Dashevskaya B.I. and Yavlinskii M.D.
Malsobiono-Zhirovaya Prom. 20 No. 4-22-6 (1955) Chern.
Abstr. 49 13667a (1955).
Zhuze T.P., Yushkevich G.N. and Gekker I.E., Med.
Prom. SSR 16, No.8, 41-4 (1962). Chern. Abstr. 58
4747g (1963).
Gurevich I.L., Zhake L. Yu, Sukhareva T.N., Neltekhim. i Gaz. Prom. No. 51, 214-17 (1964). Chern. Abstr.
62 16522f (1965).
Snyder E., U.S. Pat 2, 417, 329, Jan. 1944.
Truter E.V., Wool Wax Chern. & Tech., Clever-Hume
Press Ltd. London (1956),
Nyman, Doris M. U.S. Pat. 3, 338, 933, Aug. 1967. Chern.
Abstr., NQv. 27, No. 22, 101280e (1967).
Ghosh, S. K. and Rawat, B.S., Indian Pat. 106419,
July 1966.
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