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Патент USA US2408906

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2,408,905
Patented Oct. 8, 1946
UNITED STATES PATENT OFFICE
2,408,905
PREPARATION OF SYNTHETIC GLYCERIDES
Howard C. Black and Charles A. Overley, Chi
cago, 111., assignors to Industrial Patents Cor
poration, Chicago, 111., a corporation of Dela
ware
No Drawing. Application November 29, 1941,
Serial No. 420,942
9 Claims. (Cl. 260—d10.6)
1
2
This invention relates to the preparation of
chemically pure esters of polyhydroxy compounds
ing one unsaturated bond are the acids of the
and unsaturated acids.
'
oleic acid series such as acrylic, crotonic, angelic,
tiglic, methacrylic, lauroleic, myristoleic, palmi
’
toleic, oleic, erucic, brassidic, elaidic and ricin
oleic acids. Examples of monocarboxylic acids
having two unsaturated bonds are the acids of
'One of the objects of this invention is to pro
vide a method for the synthesis of pure esters
of polyhydroxy compounds, for example, polyhy
droxy alcohols, and unsaturated organic acids.
Other objects and advantages of this inven—
tion will become apparent from the description
and claims which follow.
It has been found difficult to produce pure es
ters of unsaturated acids and polyhydroxy com
the linoleic acid series, such as tariric and linoleic
acids. Examples of monocarboxylic acids hav
ing three unsaturated bonds are linolenic and
10 elaeostearic
acids. Examples of dicarboxylic
acids, having one unsaturated bond are aconitic,_
itaconic, citraconic, maleic and fumaric acids.
The unsaturated acid is ?rst brominated to
protect the unsaturated bonds. The bromine ad
pounds, for example, glycerol, by direct esteri
?cation due to oxidation ‘and polymerization of
the unsaturated acids at the unsaturated bonds 15 dition product is then converted to an acid chlo
ride by the use of, for example, thionyl chloride,
during the attempted synthesis. To facilitate
the esteri?cation and prevent oxidation and poly
merization of the unsaturated acids during the
phosphorus trichloride or phosphorus pentachloa
ride. In the preparation of glycerides, for ex
ample, the acid chloride of the bromine addition
chlorides or anhydrides of the unsaturated acids 20 product is then dissolved in a solvent in which,
glycerol or acetoneglycerol and a nitrogenous
before reacting the materials with the polyhy
base is also soluble, such as chlorinated hydro‘
droxy compound. In forming the acid chlorides
carbons, for example, dry chloroform, carbon tet
or anhydrides of the unsaturated acids, oxida
rachloride, ethylene dichloride, and acetylene tet
tion, polymerization and ‘decomposition of the
acids at the unsaturated bonds occur, and yields 25 rachloride. The purpose of employing a solvent
is to produce a single homogeneous phase of the
of pure acid chlorides or anhydrides of the un
reaction mixture. 'If the solvent is not employed,
saturated acids are low. After the pure acid
mixing of the reagents is difficult.
chloride or anhydride has been produced, some
Acetonegl'ycerol ‘is a condensation product
oxidation and polymerization of the unsaturated
bonds occur during the reaction of the acid chlo 30 formed by the reaction of glycerol and acetone in
reaction, it has been proposed to form the acid
the presence of anhydrous sodium sulphate and
ride or anhydride with the polyhydroxy com
hydrochloric acid. Two of the hydroxyl groups
pound. The resulting synthetic esters of the poly
hydroxy compound and the unsaturated, acids
of the glycerol are thereby covered or removed
from the sphere of reaction, leaving but one hy
consist of a variety of individual compounds and
the product is not a pure ester of the polyhy 35 droxyl group free to react with the acid chloride
of the bromine addition product, and the for
droxy compound and the unsaturated acids.
mation of the‘ monoacid ester is thereby assured.
The present invention contemplates the prep
The formation of acetoneglycerol may be repre
aration of the acid chlorides of bromine addition
sented by the following equation: .
products of unsaturated acids, which are then
reacted with the polyhydroxy compound, and 40
the subsequent removal of the bromine to yield
the pure ester of the polyhydroxy compound and
the unsaturated acids. The method of the pres
ent invention may be employed, for example, in
the preparation of pure synthetic monoacid, di
acid, and triacid esters‘of glycerin and unsatu
rated acids, monoacid and diacid esters of eth
ylene glycol, monoacid and diacid esters of di
ethylene glycol, and ‘the like. This method may
also be employed in preparing mixed glycerides
H2 0 OH
0 H3
/
—-—»
\
45 H2OOH
Glycerol
50
55
HO O
Nazs 0 4
HCOH + O=C
of unsaturated “acids ‘and mixed glycerides of
saturated and unsaturated fatty acids.
,
The method of this invention is applicable to
the preparation of any ester of a polyhydroxy
compound and unsaturated organic acids. Ex
amples of monocarboxylic unsaturated acids hav
H2 C O H
C ‘
H Cl
CH3
0 Hz
\ /
+ H20
/ \
'
H200
Acetone
(_1)
CH3
Acetoneglycerol
The solution of the acid chloride of the bro
mine addition product is then added to a cold
mixture of acetoneglycerol and quinoline, or other
suitable nitrogenous base, such as pyridine, ani
line, and the like. Quinoline, or other nitrog
enous base is employed to react with the hydrogen
chloride liberated by the reaction between the acid
chloride of the bromine addition product and
acetoneglycerol.
'
.
2,408,905
l
3
4
The mixture is allowed to stand for a number
of hours and is then taken up in ether and washed
successively several times with cold dilute sul
phuric acid, saturated sodium bicarbonate solu
small proportions through the condenser over at
period of about one hour to convert the tetra-i
bromostearic acid into 9, 10, 12, 13-t/etrabromo- ,
stearoyl chloride which may be represented by
tion, and water. The ether solution is dried over
anhydrous sodium sulphate and is then held at a
low temperature to precipitate the ester formed
by the reaction between the acid chloride of the
the formula RCOCl. The mixture was then al
lowed to cool to room- temperature and held at
room temmrature over night.
The oily mass was taken up in about 250 cc.
of anhydrous petroleum ether and the solution
bromine addition product and acetoneglycerol.
The ester may be removed by ?ltration and re
10 was then cooled to about —26 degrees C., and held
at this temperature for several hours. The tetra
crystallized from a mixture of equal parts of ether
and petroleum ether. The ester formed by the
reaction of the polyhydroxy compound and the
bromostearoyl chloride crystallized into shiny
acid chloride of the bromine addition product ‘
perature and washed with cold petroleum ether
white ?akes which were ?ltered at the low tem
until most of the excess thionyl chloride was re
may be liberated from the acetone condensation
moved. The product was then carefully dried
product by replacing the hydroxyl groups in the
glycerol or polyhydroxyl part of the reaction
under vacuum. If desired, the tetrabromostear
oyl chloride may be recrystallized from anhydrous
product or hydrolyzing the reaction product by
ether or petroleum ether. The yield of product
dissolving the crystallized or precipitated material
in ether and adding cold concentrated hydro 20 in following the procedure set forth was rI8 grams
of tetrabromostearoyl chloride.
chloric acid.
In the preparation of the monoacid ester of
The mixture may be allowed to stand over
night at low temperatures to crystallize the
glycerol and linoleic acid, a cold mixture of 10
grams (0.075 mole) of acetoneglycerol and 9.6
brominated ester, after which the ester may be
?ltered from the liquor and washed free of chlo 25 grams (0.075 mole) of quinoline was placed in a
rides with cold water. The ester may then be
glass stoppered flask, and 45 grams (0.073 mole)
dried in a vacuum and recrystallized from ether,
of tetrabromostearoyl chloride dissolved in 20 cc.
if desired.
of dry chloroform added to the cold mixture of
acetoneglycerol and quinoline in small portions
The brominated ester is then debrominated by
treatment with zinc and anhydrous alcohol. 30 while cooling and agitating the mixture. The
Other solvents may be employed in place of al
mass was then allowed to stand for about forty
eight hours at room temperature.
cohol, such as benzene, toluene and xylene, but We
prefer to employ alcohol. The alcohol may be
The slight excess of acetoneglycerol is em
re?uxed and the zinc removed by ?ltration. The
ployed to insure that no free acid chloride re
?ltrate is washed several times with water and
mains in the reaction mixture. Free acid chlo
?nally dried over anhydrous sodium sulphate and ‘
ride will be converted into the free fatty acid
evaporated in vacuo. The liquid is then taken
when the product is taken up in ether and washed
up in a mixture of equal parts of ether and
v with water. The fatty acid is more di?icult to
petroleum ether and is allowed to crystallize at
separate from the ester than the acetoneglycerol.
reduced temperatures. The crystals of pure un 40 Equimolar quantities of the acid chloride and
saturated esters may be removed from the liquor
acetoneglycerol, however, may be used. A slight
by ?ltration, and then dried.
excess of quinoline is also employed to insure a
By way of illustration, but not by way of limi
complete removal of the hydrogen chloride
tation, the present method is speci?cally described
formed by the reaction.
in the preparation of monoacid, diacid, and tri 45
The reaction may be represented by the follow
ing equation:
acid esters of glycerol and linoleic acid.
The bromine derivative of linoleic acid, namely,
tetrabromostearic acid, was prepared by bromina
tion of the acetone soluble fraction of cottonseed
oil fatty acids. The acetone soluble fraction of 50
cottonseed oil fatty acids was obtained by dissolv
ing the mixture of fatty acids derived from cot
tonseed oil in about 4 volumes of acetone. The
solution was then cooled to —15 degrees C. and
maintained at this temperature for several hours.
The precipitated acids were removed by ?ltration,
and the acetone in the ?ltrate was removed by
evaporation. The acids obtained by evaporation
of the acetone were dissolved in dry petroleum
ether and bromine added while maintaining the 60
mass at about 20 degrees C. and continuing the
bromine addition until no more bromine was ab
sorbed. The tetrabromostearic acid separated in
white crystals which were removed by ?ltration,
and puri?ed by recrystallization from a mixture
of ether and petroleum ether. The bromine de
rivative of linoleic acid is 9, 10, 12, 13-tetrabromo
stearic acid and may be represented by the for
mula RCOOH.
In a speci?c example, 80 grams of tetrabromo
H 0 CE 2
110001
itJ,t10,bl2,
13e rs romo
stearoyl
chloride
+ H3O
\ /
OCH + Quinoline
/C\ 0
H30
——->
B1
Acetoneglycerol
R C 0 O CH:
[BC
0 CH
\C/
113C
/ \
+ Quinoline-HCI
(2)
0 CH2
Ester of brominated acid and accloncglycerol
The material was taken up in about 150 cc. of
cold ether and washed successively several times
with cold 0.5 N sulphuric acid, saturated sodium
bicarbonate solution, and water. The ether solu
tion was dried over anhydrous sodium sulphate
and was then cooled to about —26 degrees C.
The gummy precipitate was ?ltered and recrys
tallized from a mixture of ether and petroleum
ether at a temperature of about —26 degrees C.
be yield was about 35.5 grams of the ester.
The monoacid ester of glycerol and tetrabromo
stearic acid was placed in a flask and heated in an
stearic acid was liberated from the acetone con
oil bath to a temperature of about 120 de—
grees C. The ?ask is preferably provided with a
groups in the glycerol part of the ester or by hy
densation product by replacing the hydroxyl
re?ux condenser, and after the acid has been
drolyzing the reaction product by dissolving the
melted, 15 grams of thionyl chloride was added in 75 recrystallized precipitate in about 300 cc. of ether,
2,408,905,
5
cooling the liquid in an ice bath, and adding
about 360 cc. cold concentrated hydrochloric acid
in portions while vigorously agitating the mass.
The mixture was then cooled to about —.26 de
grees 0., and the semicrystalline solid ?ltered and
washed free of chlorides with cold water.
H2(|'J.OH
HOOH + 01
The
I
solids were then dried under vacuum and, re
H2O OH
crystallized from about 500 cc. ether at zero de
Glycerol
CG
+ pyridine
Dry
_-_>
I
grees C. The recrystallized product appeared as
plates when examined under a high powered mi 10
croscope.
The yield was 26 grams of the mono
'l‘riphenylmethyl chloride
acid ester of glycerol and tetrabromostearic. acid.
The replacement of the hydroxyl groups, or the
hydrolysis of the reaction product,‘ or the libera
tion of the monoacid ester of glycerol and tetra
bromostearic acid from the acetone condensa
tion product may be represented as follows:
RC 0 0 ?H2
(3)
H30
H3O
\ /
0011
Ether
OCHz
H2COOOR
H1O OH
Monoacid glyceride
7
.
H2? OH
H? OH
HzCO-———(IJ——C> + Pyridine-H01
CH3
I
9 l 1 13'
CH3
Acetone
a-monotrytylglycerol
A cold mixture of the above described glycerol
derivatives and quinoline in the proportion of
about 1 mole of glycerol derivative to 2 moles of
quinoline was placed in a glass stoppered flask
and tetrabromostearoyl chloride dissolved in dry
o
tetrabromosteanc acid
The monoacid ester of glycerol and tetrabro
mostearic acid was then debrominated t0 rees
tablish the unsaturated bonds by treating‘ 20 gram
portions of the tetrabromo derivative with 20
grams of ?nely granulated zinc and 50 cc anhy
drous alcohol. The granulated zinc is first thor
oughly washed with dilute hydrochloric acid and
then with water and carefully dried before use.
After mixing the tetrabromo derivative, zinc, and
anhydrous alcohol in a ?ask, the mixture was
chloroform was added to the cold mixture in small
proportions While cooling and agitating the mix
ture. The quantity of tetrabromostearoyl chlo
ride added was slightly in excess of two moles. A
slight excess of the tetrabromostearoyl chloride
is employed to insure that no free hydroxyl groups
remain in the glycerol derivative, and insure an
esteri?cation of both hydroxyl groups. Free acid
chloride will be converted into free fatty acid
when the product is taken up in ether and
washed with water. The fatty acid is easier to
separate from the diacid ester than the monoacid
esters of glycerol which are formed when less
warmed gently in a Water bath until a vigorous
exothermic reaction occurred and the ?ask of
material was then transferred to an, ice bath.
The ?ask was ?tted with a re?ux condenser and
the alcohol re?uxed for about one half hour.
The zinc was then removed by ?ltration. The
?ltrate was taken up in ether and washed several
times with water to remove the alcohol and any
than 2 moles of acid are used in the reaction.
However, the acid chloride and the glycerol de
rivative may be employed in the proportion of
inorganic substances which may be present, and
?nally dried over anhydrous sodium sulphate.
2 to 1, if desired. A slight excess of quinoline is
The liquid Was then evaporated under a vac
preferably employed to insure a complete removal
of the hydrogen chloride liberated by the reac
tion.
The reaction may be represented by the follow
uum, and the nearly colorless oily material was
taken up in 30 cc. of a mixture of equal parts of
ether and petroleum ether and cooled to about
—-26 degrees C.
(5)
The solution was held at this
temperature over night to crystallize the ester.
The crystals were removed by ?ltration and dried
at a low temperature. On raising the tempera
ture of the dry crystalline material to about room
temperature, the crystals melted to form a color
less viscous oil. The yield of monoacid ester of
ing equation:
.
H 0 CH2
RC 0 01
glycerol and linoleic acid was about 8.9 grams.
The iodine value of the synthetic monoacid es
ter of glycerol and linoleic acid was 142.1, where
as the calculated iodine value for the pure ester (ill
is 143.3. The saponification value of the ester was
158.5 whereas the calculated saponi?cation value
for the ester is 158.3. The melting point of the
I
+
, .O\ HO OH
R C 0 01
I
Tetrabromo-
\
+ quinoline ———->
I
O-GH;
orll’lOnOIJl‘Ytyl
stearoyl
chloride
glycerol
ester was determined as being 14.0-15.0 degrees C.
In the preparation of the diacid esters of
glycerol and linoleic acid, a-Il'lOlflOlOdOhYdflll or
a-monotrytylglycerol may be used. The forma
tion of these glycerol derivatives may be repre
sented by the following equations:
RC 0 O CH:
_
'
R000 CH
+
quinoline-HCl
70
Glycerol Hydrogen
iodide
a-monoiodohydrin
75
Ester of brominated acid and wmonotrytylglycerol
(6)
2,408,905
7
8
The reaction mass is then allowed to stand at
over anhydrous sodium sulphate. This procedure
room temperature for about 48 hours. The mass
is then taken up in cold ether and washed suc
is suf?ciently vigorous to cause the a-, ?-diacid
cessively several times with cold dilute sulphuric
acid, saturated sodium bicarbonate solution and
04-, a-diacid glyceride.
The dried ?ltrate may then be evaporated un
der a vacuum and the only residue may be taken
up in a mixture of equal parts of ether and petro
leum ether and cooled to about —26 degrees C.
The solution may be held at this temperature over
night to crystallize the diacid esters of glycerol
and linoleic acid and the crystals may then be
removed by ?ltration and dried at a low tempera
ture. On raising the temperature of the dry
crystalline material to about room temperature,
the crystals melt to form a colorless viscous oil.
In the preparation of the triacid ester of
glycerol and linoleic acid, in a speci?c example,
a cold mixture of 2.2 grams (0.024 mole) glycerol
and 9.6 grams (0.075 mole) quinoline was placed
in a ?ask, and 45 grams (0.073 mole) tetrabromo
stearoyl chloride dissolved in 30 cc. dry chloro
form was added in small portions While cooling
and agitating the mixture. The semisolid mass
was permitted to stand at room temperature for
two days and then taken up in 600 cc. of ether.
The solution was then washed successively with
water.
glyceride to be at least partially converted to the
The ether solution is then dried over
anhydrous sodium sulphate and cooled to about
—26 degrees C. The precipitate may be ?ltered
from the ether solution and recrystallized from
a mixture of ether and petroleum ether at a 10
temperature of about —26 degrees C.
The diacid ester of glycerol and tetrabromo
stearic acid may be liberated from the ester of
the triphenylmethyl glycerol condensation prod
uct by dissolving the recrystallized precipitate in 15
ether, cooling the solution in an ice bath, and
adding hydrogen chloride in portions while vigor
ously agitating the mass. The mixture may be
then cooled to and held at about —26 degrees C.
and the semicrystalline ester ?ltered and washed 20
free of chlorides with cold water. The ester may
be then dried under vacuum and recrystallized
from ether.
The liberation of the diacid ester of glycerol
and tetrabromostearic acid or the replacement as
of the hydroxyl groups in the glycerol part of the
ester may be represented as follows:
RCOOCH:
0.5 N sulphuric acid, saturated sodium bicarbon
ate solution and water. The ether solution was
then dried over anhydrous sodium sulphate and
30 cooled to a temperature of about zero degrees C.
The liquid was held at this temperature over
night, and the crystals which were formed were
removed by ?ltration and recrystallized from
ether. The recrystallized material appeared to
35 be needlelike in form under a lower power micro
ether
ROOOOH + H01 --—>
Geo-em
scope and appeared to be long thin plates under
high power. The yield was 30.5 grams of glycerol
tritetrabromostearin.
(7)
The slight excess of acid chloride is employed
40 in preparing triacid glycerides to insure the
esteri?cation of all hydroxyl groups of the glycerol
and to insure that no monoacid or diacid glyc
HzCOOCR
erides remain in the product. The free fatty acid
‘La LI
formed from the excess acid chloride when the
product is taken up in ether and washed with
water is separated with greater facility from the
triacid glyceride than monoacid and diacid glyc
erides. Equimolar quantities of the acid chloride
tetrabromo
stearic acid
and glycerol, however, may be used. A slight ex
Triphenyl-metliyl 550 cess of quinoline is employed to insure a complete
chloride
removal of the hydrogen chloride formed by the
reaction.
Although, in the equations above, the use of
The reaction may be represented by the follow
u-monotrytylglycerol has been illustrated, it is
ing
equation:
apparent that a-monoiodohydrin may be repre
Diacid
glyceride of
sented in a similar manner. However, in the re
moval of iodine from the ester of a-monoiodo
hydrin, the conditions are sui?ciently vigorous to
cause rearrangement of the acid radicals to form
the (1-, a-diacid glyceride. The iodine is removed
by heating the iodine compound in alcohol in the 60
presence of silver nitrite.
The diacid ester of glycerol and linoleic acid
is formed by debrominating the ester of glycerol
and tetrabromostearic acid, whereby the unsatu
rated bonds are reestablished in the acid radicals.
Debromination may be effected by treating the
ester of glycerol and tetrabromostearic acid with
?nely granulated zinc and anhydrous alcohol.
After mixing the glycerol derivative, zinc and an
hydrous alcohol in a ?ask, the mixture may be
warmed gently, for example, in a water bath,
until a vigorous exothermic reaction occurs and
the ?ask is then transferred to an ice bath. The
zinc may be removed ‘by ?ltration and the ?ltrate
washed several times with water and ?nely dried
R C 0 01
HO OH:
RC 0 C1 + HO OH + quinoline -->
R O 0 Cl
H 0 CH2
9,10,12,13stearoyl
Glycerol
tetrabromo
chloride
HzC-O 0 C R
HC-O O C R + quinolino.HCl
(8)
HzC—O O C R
Glycerol
tritetra
bromostearin
The ester was then debrominated to reestablish
the unsaturated bonds by treating 20 gram lots
with 20 grams of ?nely granulated zinc and 50
cc. anhydrous alcohol. The zinc was ?rst washed
with dilute hydrochloric acid, then with water,
_ and carefully dried before being employed in this
step.
The ?ask was then warmed gently in a
2,408,905
10
9 .
water bath until a vigorous exothermic reaction
set in, and the flask was then transferred to an
ice bath. The flask was ?tted with a reflux con
denser, and the alcohol was re?uxed for about one
half hour, after which the zinc was removed by
?ltration. The ?ltrate was taken up in ether
and washed several times ‘with water and ?nally
dried over anhydrous sodium sulphate and evap~
orated under vacuum. On dissolving the color
less oil in a mixture of equal parts of ether and
petroleum ether and holding the solution at —25
degrees C. over night, no crystals were produced.
The solvent was removed by evaporation under
which one of the hydroXYl groups is replaced ‘by
linoleic acid and the other two replaced by lino
lenic acid, the monoacid ester of the tetrabromo
stearic acid and glycerol is ?rst prepared by re- ,
acting the tetrabromostearoyl chloride with the
acetoneglycerol condensation product in the pres
ence of
nitrogenous base such as ,quinolin'e,
as represented by Equation 2.
The ester of tetrabromostearic acid and ace
toneglycerol is then treated with water, ether
and hydrochloric acid to liberate the monoacid
ester of tetrabromostearic acid and glycerol, as
illustrated in Equation 3.
vacuum.
The ester is then reacted with the hexabromo
The triacid ester of glycerol and linoleic acid 15 stearoyl chloride in the presence of quinoline or
had an iodine value of 171.2 whereas the calcu
other nitrogenous base to form a mixed glyceride
lated value for the ester is 173.3. The saponi?ca
illustrated in the following equation:
tion value of the ester was 191.2 whereas the cal~
culated saponi?cation value is 191.5. The melt
ing' point of the product is 5.0-4.0 degrees C.
20 R’COCI
That the acid radical of the esters prepared
R’COOI
by the above procedures is linoleic acid may be
RCOOCH:
HO
H +
quinoline --—>
HOCHz
easily determined by saponifying the esters by
HzGOOCR
treatment with 5 per cent alcoholic sodium hy
HGOOCR’ + quinoline-HvCl
droxide and isolating the fatty acid by acidi?ca
tion and extraction with petroleum ether. For
HzCOOCR’
(9)
_
example, 6 gram samples of the monoacid ester
and the triacid ester Were allowed to stand over
The ester of glycerol and linoleic and linolenic
night with 75 cc. of 5 per cent alcoholic sodium
acids may be formed byv debromination of the
hydroxide. The fatty acids were isolated by acidi 30 bromine derivative to reestablish the unsaturated
?cation and extraction ‘with petroleum ether.
The acids so isolated may then be brominated and
the tetrabromostearic acid may be identi?ed by
a melting point determination.
For example, the acids isolated from the esters
as described above were brominated by taking
5 grams of the acid and brominating the acid
bonds by treatment with ?nely granulated-puri
?ed zinc and anhydrous alcohol.
The reactions, crystallization and drying » of
the materials at the different stages in the proc
css may be carried out as described above in the
preparation of monoacid esters and triacid. esters
of glycerol.
in 80 cc. of petroleum ether at about 20 degrees
It is apparent that if desired, a diacid glyceride
C. The yield of the brominated product was 4.5
may ?rst be prepared by reacting the acid chlo
grams of crystalline material, which had a melt
ride with a-monoiodohydrin or d-monotrytylgly
ing point of 115.5 degrees C. Similarly, 5 grams 40 cerol in the presence of quinoline, for example,
of linoleic acid obtained by debromination of the
as illustrated in Equation 6. vThe diacid ester
tetrabrornostearic acid was brominated to yield
of the brominated acid and the glycerol deriva
4.5 grams of crystalline material having a melt
tive is then liberated from the condensation prod
ing point or 115.5 degrees C. The tetrabromide
uct to form the diacid glyceride of the bromi
of the acid isolated from a mixture of the mono
nated acid. The diacid glyceride of the bromi
acid and triacid esters prepared as above also
nated acid is then reacted with the acid chlo
had a melting point of 115.5 degrees C.
ride of the second acid in the presence of quinc
In the preparation of mixed glycerides, for
line to form the mixed triacid ester of glycerol
example, triglycerides, containing two different
and the two acids. The successive reactions may
acid radicals, the monoacid glyceride of an acid
be illustrated by the following’ equations:
may ?rst be formed and the monoacid glyceride
then reacted with an acid chloride of a di?erent
acid. If desired, the diacid glyceride of an acid
may first be formed and then treated with an
acid chloride or" a different acid to form the
B0001
HOG/‘H2
B0001
HOOH + quinoline —)
mixed glyceride. If desired, each of the hy
droxyl groups of .the glycerol may be replaced
with a different acid radical.
For example, the method of the present inven
tion may be illustrated by the preparation of a 60
triglyceride in which one of the hydroxyl groups
is replaced by linoleic acid and the other two hy
droxyl groups may be replaced by linolenic acid.
‘The acids are ?rst lorominated to protect the
unsaturated bonds.
The bromine derivative of
linoleic acid is 9, 10, 12, 13-tetrabromostearic acid.
The bromine derivative of linolenic acid is 9, 10,
12, 13, 15, 16-hexabromostearic acid. The bro
mine addition products are then converted into
acid chlorides, namely, 9, 10, 12, 13-tetrabromo
stearoyl chloride and 9, 10, 12, 13, 15, 16-hexa
bromostearoyl chloride, which may be repre
sented by RCOCl, and R’COCl, respectively.
In the preparation of an ester of glycerol in 75
RC 0 0 CH1
R00 0 OH + quinoline'HCl (10)
Geo-e
2408305
"11
12
The resulting product is then reacted with the
acid chloride of the second brominated acid and
the resulting ester then converted to the diacid
ester of glycerol and the two brominated acids,
as represented by the Equations 14 and 15. In
RCOOCH:
ether
RCOOCH + 1101 —-—>
1
O +011:
the conversion to the ester of glycerol, the re
action may be su?iciently vigorous to cause at
least a portion of the 41-, ?-diacid glyceride to be
converted to the 04-, u-diacid glyceride.
10
RCOOCH:
R'COC1+ HOCH + quinoline —-—+
3000013,
R000 3+ 01- Q (11)
noon,
Roooorn
RCOOCH:
R'COC1+ 110002;}: + quinoline --->
‘
HO H:
R'COO IH + quinolinc.HCl (l4)
<3 —-<»—@H,
120000111
RG00 H + quinoline-HCI (12)
R’OOOOH:
If it is desired to prepare a triacid ester of
30
glycerol in which each of the hydroxyl groups of
the glycerol are replaced by a different acid
radical, the unsaturated acids are ?rst bromi
nated to protect the unsaturated bonds. The 35
brominated acids are then converted to acid
chlorides. It is apparent that if one of the hy
droxyl groups is to be replaced by a saturated
acid, the acid need not be brominated before
converting it into the acid chloride. The acid 40
chlorides may
RCOOCH,
ether
R’COO$H + H01 ——->
Owe-CH
be represented by RCQCL,
R’COCL and R"COCL.
_
In the preparation of the glycerol ester, a
monoacid ester is ?rst prepared by reacting the
brominated acid chloride with acetoneglycerol in 45
the presence of quinoline. The ester of the
brominated acid and acetoneglycerol condensa
tion product is then converted to the monoacid
ester of the brominated acid and glycerol. These
reactions are represented by Equations 2 and 3.
50
The monoacid ester is then reacted with tri
phenylmethyl chloride to protect one of the hy
droxyl groups of the glycerol part of the mono
acid ester, as illustrated by the following equa
tion:
55
RCOOE‘JH;
H0511:
a'oooon + 0-0-01 (1s)
The diacid ester is then reacted with the acid
chloride of the third acid to form a triacid ester
‘of glycerol in which each of the hydroxyl groups
of the glycerol molecule are replaced by different
acid radicals. This reaction may be represented
RCOOCH:
by the following equation:
I
Q I -c1 + Boon + pyridine _-,
HOCH:
RCOOCH,
R”COCl + R’COOCH + quinoline -——-§
HOCH:
RCOOCH;
R'COO H + quinoline.HC1
RC 0 0 OH:
HO CH + pyridine.HCl (13)
(16)
R"COOCHI
The puri?cation of the various products and
the conversion of the esters of the acids and the
glycerol derivatives into the esters of the acids
and glycerol are carried out in the same manner
as described hereinbefore with respect to the
preparation of monoacid, diacid, and triacld
75 esters of glycerol.
2,408,905
14
be dried and cooled and the mixture allowed to
crystallize. The ester of the sugar and the bro
mine addition product of the acid, if an unsat
urated acid is employed, ‘or the ester of the sugar
and the saturated acid may be liberated from
the condensation product, if a derivative of the
sugar has been employed, in a manner similar to
that described above with respect to the prepara
tion of'esters of glycerol. If a bromine addition
product was employed as the starting acid radical,
the esters may be debrominated to reestablish the
unsaturated bonds by the use of, for example,
alcohol, as described above, to form the ester of
Diacid esters of ethylene glycol and diethylene
glycol may be prepared in a similar manner.
For example, the glycol and quinoline may be
dissolved in chloroform and the acid chloride
added to the solution in small proportions. The
reaction mixture is cooled continuously and agi
tated until all of the acid chloride has been added.
The reagents are employed in the ratio of one
part of the glycol to two parts of the acid chlo
ride to two parts of quinoline or pyridine. As
pointed out in connection with the preparation
of glycerides, we prefer to employ slightly more
than two parts of acid chloride and the nitrog
enous base, such as quinoline or pyridine, to in
the sugar and the unsaturated acid.
'
It is apparent that the method of the present
sure a complete esterification of the hydroxyl 15
invention permits of the preparation of esters of
groups of the glycol and to insure a complete
removal of the hydrogen chloride from the re
polyhydroxy compounds and unsaturated acids
action mixture. The mass is then allowed to
with a minimum of impurities since the unsat~
stand for about 4.8 hours at about room tempera
urated bonds of the acids are protected from poly
ture.
20 meriZation, oxidation, and other types of reac»
The esters may then be taken up in cold ether
tions during the preparation of the esters. After
and washed several times consecutively with
the esters of the polyhydroxy compounds and the
cold dilute sulphuric acid, saturated sodium bi
bromine addition product of the acid have been
carbonate solution and water. The ether solu
formed, the unsaturated bonds in the acid rad
tion may then be dried over anhydrous sodium
ical may be reestablished or restored as the final
sulphate and cooled to permit crystallization of
step in the preparation of the esters. When the
the esters.
debromination is carried out in a neutral alco
If the acid employed in forming the diacid
holic solution, there is no evidence of interesteri
esters is an unsaturated acid, it is obvious that
?cation. However, when hydrochloric acid or
the unsaturated bonds are ?rst protected by 30 free hydrogen chloride is present, small amounts
bromination. The acid chloride is then formed,
of esters, such as ethyl linoleate, may be formed.
which is employed in the reaction with the ethyl
Solvents other than alcohol which are satisfac
ene glycol. If a saturated acid is to be employed
tory for the purposes of this invention include
in the reaction with the glycol, the acid chloride
benzene, toluene and xylene.
of the acid is ?rst formed and the acid chloride O1)
We have described the use of bromine in con
reacted with the glycol. If the bromine addi
verting the unsaturated acids to saturated acids,
tion product of an unsaturated acid has been
however, it is apparent that other substances may
used, the crystallized ester of ethylene glycol
be employed. For example, iodine may be em
and the bromine addition product of the acid is
ployed, but the reaction is not as practical as that
then debrominated by treatment with ?nely 40 which occurs when bromine is employed. The
granulated zinc and alcohol to form the esters
various intermediate products, such as the halo
of ethylene glycol and the unsaturated acids.
genated acids, and esters, are not as readily sep
Esters of other polyhydroxy compounds may
arated from the reaction mixtures by crystal
also be prepared in accordance with the present
lization as the products prepared by the use of
invention. An example of a further class of poly
bromine.
hydroxy compounds is the sugars. Esters of
The use of chlorine also is not as practical as
monosaccharides, for example, galactose, glucose,
the use of bromine. When chlorine is employed in
fructose and mannose, and disaccharides, for ex
preparing the saturated acids, there is a tendency
ample, sucrose, maltose, and lactose, may be pre
and some danger that the chlorine will replace
pared in a manner similar to that described above. 50 some of the hydrogen atoms along the carbon
The sugar or sugar derivative is mixed with quin
chain. If such substitution or replacement occurs,
oline or pyridine in a suitable solvent and the acid
there is a tendency for hydrogen and chlorine
chloride then added. It is obvious that the molec
atoms on adjacent carbon atoms to split out to
ular proportions of pyridine and the acid chloride
form hydrogen chloride and produce an unsat
with respect to the sugar must be in an appropriate
urated bond where there had been previously a
relation to e?ect the desired esteri?cation of the
saturated bond. Furthermore, if the replacement
sugar. Certain of the hydroxyl groups of the
or substitution occurs at adjacent carbon atoms,
sugar may be protected or removed temporarily
and if the substituted chlorine remains linked
by reaction with a ketonic compound, for ex
to the adjacent carbon atoms throughout the
ample, acetone or benzaldehyde. For example,
various reactions, the ?nal reestablishment of
two adjacent hydroxyl groups of the glucose may
the unsaturated bonds in the ?nal product by
be protected by reaction with acetone in a man
removal of the chlorine will result in the estab
ner similar to the reaction between glycerol and
lishment of new unsaturated bonds in the acid
acetone as set forth in Equation 1. Certain of the
radical portion’ of the ester.
hydroxyl groups may be protected by reaction
In the preparation of various esters, it is not
with triphenylmethylchloride in a manner similar
necessary that the acid chlorides be employed.
to that employed in the preparation of diacid
For example, triacid glycerides and diacid glycols
may be prepared by reaction of glycerol or glycol
glycerides.
The reaction mass formed by reaction of the
with the bromine addition product of the unsat
sugar derivative and the acid chloride of the bro 70 urated acids.
mine addition product is then allowed to stand for
We claim:
n ..
one or two days after which the mass is taken
up in cold ether and washed consecutively with
1. The method of preparing esters of polyhy
droxy compounds and unsaturated higher fatty
acids which comprises saturating the unsatu
cold sulphuric acid, saturated sodium bicarbonate
solution and water. The ether solution may then 75 rated bonds of an unsaturated higher fatty acid
2,408,905
15
16 '
by halogenation to form a saturated higher fatty
rated bonds of unsaturated higher fatty acid
acid, converting the acid so saturated into an
by halogenation to form a saturated acid, con
verting the acid so saturated into an acid chlo
acid chloride, reacting the acyl derivative with
at least one hydroxyl group of a polyhydroxy
compound to form an ester and thereafter de
ride, reacting the acyl derivative with at least
halogenating the acid radical portion of the ester
in a mutual solvent to form an ester and there
to reestablish the unsaturated bonds.
after dehalogenating the acid radical portion of
the ester to reestablish the unsaturated bonds.
6. The method of preparing esters of polyhy
2, The method of preparing esters of polyhy
droxy compounds and aliphatic unsaturated
one hydroxyl group of a, polyhydroxy compound
higher fatty acids which comprises reacting the 10 droxy compounds and unsaturated higher fatty
acid chloride of a bromine addition product of
acids, which comprises halogenating the unsat
an aliphatic unsaturated higher fatty acid with
at least one hydroxyl group of a polyhydroxy
compound to form an ester, and thereafter de
urated bonds of an unsaturated higher fatty
acid, converting the acid so saturated into an
acid chloride, reacting the acyl derivative with
brominating the ester.
15 a derivative of a polyhydroxy compound having
3. The method of preparing esters of glycerol
at least one reactable hydroxyl group and at least
and aliphatic unsaturated higher fatty acids
one unesteri?able group replacing at least a part
which comprises halogenating the unsaturated
of a hydroxyl group to esterify the reactable
bonds of an aliphatic unsaturated higher fatty
hydroxyl group, hydrolyzing the reaction prod
acid, converting the acid so saturated into an 20 not to reestablish all of the hydroxyl groups in
the polyhydroxy compound portion of the prod
acid chloride, reacting the acid chloride with
at least one hydroxyl group of the glycerol to
form an ester, and thereafter dehalogenating the
acid radical portion of the glycerol ester to re
establish the unsaturated bonds.
25
4. The method of preparing monoacid esters
uct except the esteri?ed group or groups and
dehalogenating the acid radical portion of the
reaction product to reestablish the unsaturated
bonds.
7. The method according to claim 4 in which
of polyhydroxy compounds and aliphatic unsat
the derivative of the polyhydroxy compound hav
urated higher fatty acids which comprises re
ing one reactable hydroxyl group is acetoneglyc
acting the acid chloride of a, bromine addition
erol.
product of an aliphatic unsaturated higher fatty 30
8. The method of preparing triacid esters of
acid with a derivative of a polyhydroxy com
polyhydroxy compounds and aliphatic unsatu
pound having only one reactable hydroxyl group
rated higher fatty acids which comprises react
and at least one unesteri?able group replacing
ing the acid chloride of a bromine addition prod
at least a part of a hydroxyl group to esterify
uct of an unsaturated higher fatty acid with a
the reactable hydroxyl group, hydrolyzing the 35 derivative of a polyhydroxy compound having
reaction product to reestablish all of the hy
three reactable hydroxyl groups to esterify said
droxyl groups in the polyhydroxy compound por
three hydroxyl groups and then debrominating
tion of the product except the esteri?ed group,
the resulting ester.
and debrominating the resulting product.
9. The method according to claim 8 in which
5. The method of preparing esters of polyhy 40 the polyhydroxy compound is glycerol.
droxy compounds and unsaturated higher fatty
HOWARD C. BLACK.
acids, which comprises saturating the unsatu
CHARLES A, OVERLEY.
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