Note: Descriptions are shown in the official language in which they were submitted.
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The invention relates to a method of producing acid amides of
naturally occurring fatty acids by direct reaction of crude fats
and oils with amide-forming reagents.
At all times, oils and fats of vegetable and animal origin have
been important raw materials both for human nutrition and for the
production of key chemicals to be used in the manufacture of
textile finishing products, paints, varnishes and similar products,
cosmetics, candles, soap, surfactants, lubricants, softening
agents, cement and asphalt additives, plastics, as well as the
production of free fatty acids. In view of diminishing raw
materials reserves, e.g. mineral oil reserves, it can be assumed
that naturally occurring fats and oils as renewable raw materials
will gain increasing industrial importance in the future.
~ndustrial production of chemical elements from fats and oils is
not without problems however. Thus, the crude fats and oils that
can be won from oil seeds often contain numerous undesired
companion substances such as phosphatides, mucilaginous substances,
pigments and odorous substances or hydrocarb~ns. Such companion
substances impede direct processing of these crude fats and oils.
For example, they can act as catalysts which, especially in the
presence of larger quantities of unsaturated fatty acids, cause
decomposition or resinification of the initial substance so that
the potential yield is considerably reduced. Therefore the crude
fats and oils can only be processed into useful chemical elements
after they have been subjected to complicated and costly methods
such as desliming, deacidification, decolouration and deodoration
to free them from such ingredients. Oleochemistry, which deals with
the chemical-technical processing of oils and fats into secondary
products, therefore gets its raw materials usually in the form of
pre-cleaned triglycerides from the oil and fat producing industry,
e.g. from oil mills. In this connection the problem arises,
however, that the oil mills are designed for handling large
quantities of oil seeds, so that processing oils seeds that are
available only in small quantities is hardly possible. Thus, the
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oils from new breeds of oil-producing plants such as the "high-
oleic" sunflower breed or Euphorbia lathyris, which, because of
their special fatty acid composition, are particularly suitable
initial substances for high-percentage oleic acid, are excluded
from industrial-scale utilisation because of the uneconomical
cleaning process they require. A further drawback of some oil seeds
is that in addition to the said companion substances they often
have ingredients that are hazardous from the point of view of
nutritional physiology, if not toxic, and that this fact alone
makes the oils unsuited for processing in facilities that also
serve to produce fats for human consumption and would therefore
have to be cleaned at an enormous expense of effort and money.
Therefore it is the object of this invention to provide a method
by which crude oils and fats can be used directly as initial
substances, without complex cleaning procedures, and to render the
oils from those kinds of oil seed into useful raw materials whose
production involves great difficulties because the oil seeds are
only available in small quantities or contain problematic
ingredients.
Surprisingly, it was found that the amides of fatty acids can also
be recovered at high purity by reacting the crude oils from oil
presses with amide-forming reagents.
Even oils that are highly reactive because of the large number of
double bonds they contain, e.g. linseed oil, can be reacted without
problem by means of this method. Therefore the subject matter of
the invention is a method as claimed in Claim 1.
Basically any kind of fat and oil can be used as initial substance
for the method according to the invention. In the following, the
terms fat and oil are used to denote those products of vegetable
or animal origin which consist chiefly of mixed glycerol esters of
higher fatty acids, i.e. primarily triglycerides, but which can
of course also contain undetermined amounts of monoglycerides,
diglycerides or other naturally occurring fatty acid esters. The
method is particularly suitable for reacting crude fats and oils
such as can be obtained by the usual methods, e.g. cold or hot
pressing in worm or screw presses, or by press extraction. Those
fats and oils are preferably used which have a particularly high
content of functional or extraordinary fatty acids, because the
appropriate fatty acid derivatives can be obtained particularyl
easily from these substances at high yield and great purity. The
content of ordinary functional fatty acids should preferably amount
to at least 50 %, that of extraordinary fatty acids to at least
10 %, always related to the total number of fatty acid molecules.
Preferably used oils are the oil of ~uphorbia lathyris, sunflower
oil rich in linoleic acid or oleic acid, in particular the i'high-
oleic" kind of sunflower oil, hardened and unhardened castor oil,
linseed oil, rapeseed oil, especially that which is rich in erucic
acid, the oil of Jatropha curcas, olive oil or the oil from marine
animals such as ~ish or whale oil. It is advisable that any solid
matter that is possibly contained in the initial substances, such
as wood or plant residues, be removed prior to the reaction. The
initial reaction batch may be varied at will, so that bascially the
method can be applied both in the laboratory and at the industrial
scale.
The fats and oils are reacted directly with the amide-forming
substances. Amide-forming substances include, for example, ammonia,
formamide or primary and secondary aliphatic, cyclo-aliphatic,
aliphatic-aromatic and aromatic amines, preferably monoamines or
diamines wlth 1 - 44 car~on atoms. This also includes dimeric fatty
acids from nati~e fats and oils. The amines may bear additional
reactive functional groups, e.g., OH groups. In the case of
diamines, additional structural elements or functional groups may
be arranged between the two amino functions in the hydrocarbon
chain or at the cylcoaliphatic or aromatic residue, for example
ether groups, amino groups, diamide groupin~s, ~etone groups or
sulphone groups. Preferred amino compounds are methylamine,
ethylamine, methylethylamine, dimethylamine, diethylamine,
morpholine, benzylamine, naphthylamine, phenylethylamine, aniline,
toluidine, diethylenetriamine, 1,~-diaminoethane, 1,3-
diaminopropane, 1,6-diaminohexane, 1,8-diaminooctane, piperazine,
~,7,10-trioxatridecane-1,13-diamine,3,3'-diaminodiphenylsulphone,
3,3'-dimethyl-4,4'-diaminodicyclo-hexylmethane, ethanolamine, 3-
aminopropanol and commercially available ether diamines with the
structural formula
CH,
H2N~CHCH[OCH2~H]nNH2/
CH,
where n is an integral number between 1 and 2000.
1,2-diaminoethane and 1,6-diaminohexane are particularly preferable
compounds.
The amines are preferably used in stoichometric quantities related
to the number of amino functions and fatty acid residues, but a
minor excess or deficiency of amino functions does not influence
the yield of the reaction substantially.
The reaction can also be performed with an appropriate solvent to
assure a homogeneous reaction process. Non-polar solvents are
usually employed for this, in particular toluene, ~ylene or
petroleum ether.
The reaction can occur at temperatures bet~een 20 and 300C, but
the temperature range between 50 and 200C is preferred, because
in this temperature range the reaction time is a reasonable 1 to
6 hours.
As a precaution, the reaction is carried out in a closed system,
e.g. an autoclave. Although it is possible to work under air, an
inert gas atmosphere, e.g. of argon or nitrogen, or of the vapour
of an inert solvent, is preferred because undesired side-reactions
such as oxidation of the initial substance can thus be suppressed
more easily.
If necessary, catalysts such as ammonium chloride or toluene-p-
sulphonic acid can be added to the reaction mixture. At appropriate
temperatures, biological catalysts such as esterases can also be
used. Other auxiliary agents and additives like polymerisation
inhibitors and antioxidants, e.g. ascorbic acid or glucose, can
also be added.
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After the reaction, i.e. no later than after the possi~ly present
solvent has been removed, the reaction products precipitate. They
are separated and then recrystallised from appropriate solvents.
Both non-polar solvents like hexane and extremely polar solvents
like sulphoxides are suitable for this. Recrystallisation from
methanol or ethanol is preferred. A simple washing process, for
example with cold methanol or toluene, is possibly also sufficient
for this. However, the reaction mixture can also be subjected to
a steam-solvent extraction process, which also yields the acid
amides in crystalline form.
When the fatty acids have been withdrawn in form of acid amides,
the companion substances of the oils and the glycerin remain in the
mother liquor in concentrated form. Some of the oil companions,
e.g. the vitamines that are always present, as well as the glycerin
are also interesting for industry. Since separation of such
concentrated mixtures is much easier, the method permits these
substances also to be recovered in a simpler way.
The acid amides produced in this way contain no undesired companion
substances and when appropriate crude oils are used, they have a
degree of purity that presents no problems in further processing.
Thus, the fatty acid amides - possibly in form of mixtures - can
either be used directly as additives, e.g. Eor lubricants, or
converted into other interesting secondary products. Particularly
interesting secondary products which so far could only be obtained
at considerable effort, if at all, are achieved, for example, from
difatty acid diamides that are obtained by reacting fats and oils
with diamines, in particular those diamides that result from oils
and fats in which one fatty acid is predominant that bears a
functional group like a carbon-carbon double bond or an OH group.
According to the invention it is possible, for example, to produce
highly concentrated dioleic acid diamides from the crude oil of
Euphorbia lathyris seeds and highly concentrated dlricinoleic acid
diamides from crude castor oil. As described in the simultansously
filed Patent Application P [396-16/(3)/9/89], such difatty acid
diamides can be reacted with appropriate difunctional compounds
like diisocyanates and thus constitute new key chemicals for the
production of prepolymers, plastics and plastic additives, e.g.,
.
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for adhesives, sealing materials, foamed plastics, lubricants and
a number of other technical auxiliary substances. With the usual
saponification methods it is also possible to produce free fatty
acids from the fatty acid amides, which is particularly
advantageous with a view to the production of rare fatty acids such
as fatty acids with five double bonds. If the fatty acids obtained
in this way comprise functional groups, they may themselves also
ser~e as basic or additive substances for plastics.
Consequently, the invention not only provides a method of
processing crude oils and fats that could not be utilised as raw
materials so far, but it also permits a large variety of new key
chemicals to be produced, or chemicals that could only be obtalned
at great effort and expense so far, and that are of great interest
for further processing in the chemical industry.
The invention is exemplified in the following.
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Example 1:
Reaction of crude euphorbia oil with 1,2-diaminoethane
100 g euphorbia oil is reacted with 9.4 g 1,2-diaminoethane in an
autoclave in nitrogen atmosphere, first 3 hours at 180C and then
another 3 hours at 100C. The reaction product is recrystallised
twice from methanol. The N,N'-ethylenebisoleodiamide obtained in
this way has a purity >90%.
(Melting point~ to 116C; yield: 73 g)
Example_2:
Reaction of castor oil with 1,2-diaminoethane
5.1 g castor oil and 0.5 g 1,2-diaminoethane are stirred for 5
hours in an autoclave in nitrogen atmosphere at 120C. The reaction
product is recrystallised from methanol. The N,N'-ethylene-
bisricinoldiamide obtained in this way has a purity >90%.
(Melting point: 83 to 85C; yield: 2.6 g)
Example 3:
Reaction of castor oil with 1,6-diaminohexane
51 g castor oil and 9.7 g 1,6-diaminohexane are stirred for 5 hours
in a nitrogen atmosphere at 100C. The reaction product is
recrystallised from 150 ml methanol. The hexamethylene-
bisricinoleic acid diamide obtained in this way has a purity >90%.
(Melting point: 86 to 88C; yield: 32 g).
2~
Exam~le 4:
Reaction of hardened castor oil with 1,2-diaminoethane
153 g hardened castor oil and 15 g 1,2 diaminoethane are stirred
for 5 hours in an autoclave in a nitrogen atmosphere at 140C. The
reaction product is recrystallised from methanol. The bis(12-
hydroxystearic acid)-N,N'-ethylenediamide obtained in this way has
a purity >90%.
(Melting point: 142-145C; yield: 106.5 g).
Example 5:
Reaction of hardened castor oil with 1,6-diaminohexane
5.1 g hardened castor oil and 0.97 1,6-diaminohexane are stirred
for 5 hours in an autoclave in nitrogen atmosphere at 150C. The
reaction product is subjected to hot vapour extraction with
methanol. The bis(1~-hydroxystearic acid)-1,6-N,N'-
hexamethylenediamide obtained in this way has a purity >90%.
(Melting point: 135-136C; yield: 3.7 g).
