Note: Descriptions are shown in the official language in which they were submitted.
- ~ ~ HOE 80~F 925
The present invention relates to gasoline mixtures
consis~ng substantially of gasoline and short-chain alco-
hols, the miscibility of these components in the presence of
water being reached with the aid of water acceptors.
Alcohol-containing fuels(gasolines) ~or internal com~
bustion engines, in particular for motorcar engines, are
of increasing interest. As alcohols there are added to
the gasoline in more or less great quanities short-chain,
straight-chain or branched aliphatic alcohols.
Mixtures of gasoline and alcohols may contain, however~
more or less great amounts of water, for example -~wing to
the fact that the hydrophilic alcohols attract water ~rom
the air. A certain water content in an alcohol-containing
gasoline is unavoidable, as a contact with the air takes
place generally in the course of the distribution and
storage of the fuel. Water is moreover present in the form
of shallow paddles at the bottom of store tanks that have
been used already so that a water-absorption of the alcohol-
containing gasoline may take place as well in this case.
The miscibility of mixtures of gasoline and alcohols, in
particular the miscibility of gasoline and alcohols with
water is unsatisfactory. In mixtures of this type a phase
separation occurs generally in more or less rapid manner,
depending on the temperature. It is evident that this is
disadvantageous for the use of said gasoline mixtures. This
tendency to separate into phases depends in particular o;n
the quantitiy of water and on the temperature of the mix-
ture. In winter, for example7 a separation may occur
already at relatively small water contents, for example of
less than 0.1 weight %.
With respect to the aforesaid circumstances there is
required a separation temperature ~characterized by the
cloud point of the mixture) as low as possible for gasoline-
alcohol-water mixtures, even in the case of relatively high
water contenl;s. To comply with these requirements, trials
have been made to lower the cloud point by adding a fourth
component to the hydrocarbon-alcohol-water mixture.
'~
_ 3 _ HOE 80/F 925
For exa~ple, European patent specification No.
00 12 3~5 recommends as a further component to water~con-
taining alcchol-gasoline mixtures an addition product of
ethylene oxide or propylene oxide to a carboxylic acld
amide having of from 8 to 22 carbon atorns and which acts
as emulsifier. This product i.s added in an effective
quantitiy.
German Offenlegungsschrif't No. 30 04 115 describes
water-containing ethanol-gasoline mixtures which contain
1~ alkyl tert. butyl ethers as solubilizer in an effective
amount.
The components which are added to water-containing
gasoline-alcohol mixtures to ressolve the problem of the
phase separation, should moreover comply with f'urther
requirements. For example, they should at least not lower
the octane number of the gasoline, they should not preci-
pitate and in particular not act in corrosive manner after
prolonged storage especially when in contact with steel,
cast iron and aluminum.
It is the task of the present invention to provide
substances that ressolve the problem of the phase separation
in gasoline-alcohol mixtures and in gasoline-alcohol-water
mixtures and that comply moreover with said requirements,
especially as regards their anticorrrosive properties. It
is in particular the task of' the present invention to
provide gasoline-alcohol mixtures, wherein a phase separa-
tion, even in the case o~ a relatively high water content
and at low temperatures, does not occur.
It has now been found surprisingly that boric acid
esters of monovalent or polyvalent alcohols are particu-
larly suitable to ressolve said task.
Sùbject of the present invention is therefore a gaso-
line mixture consiting substantially o~ gasoline and short-
chain alcohols, characterized in that it contains additio-
nally at least one boric acid ester as emulsifier and wateracceptor in an eff'ective quantity, which has been prepared
by reacting boric acid with monohydric to trihydric alcohols.
_ Ll _ O_ 80 F 925
Preferred boric acid esters accordlng to the invention
are those obtained by reacting boric acid and a monohydric to
trihydric alcohol at a molar ratio of from 1 : 0.5 to 1 : 6.
Particularly preferred boric acid esters are thoce of
the following formula I
(HO~3 nB ~ (OR )x-oR-7n
wherein
R is alkyl ~ith from 1 to 18 carbon atoms,
R1 is alkylene with from 2 to 5 carbon atoms,
the OR groups being the same or different from one another,
x is 0 or an integer of from I to 10 and
n is an integer of from 1 to 3.
The alkyl group R and the alkylene group R1 may each
be straight chain or branched.
R is preferably al~yl with from 1 to 8 carbon atoms,
R1 is preferably ethylene or propylene, x is preferably 0
or an integer of from 1 to 3 and n is preferably 3.
Preferred OR1 groups, if these groups are different
from one another, are mixed groups of oxethylene and
oxpropylene.
The effective quantity of the boric acid esters to be
used according to the present invention ranges generally
from 0.05 to 5 weight %~ preferably from 0.1 to 2 weight %,
calculated on the weight of the gasoline-alcohol mixture.
The term "gasoline" within the scope of the present
invention includes all gasolines which are used generally
for internal combustion engines. It is known that gasolines
consists substantially of a hydrocarbon mixture having a
boiling range of from 30 to 250C. Said problems apply
in particular to gasollnes containing no aromatic compounds
or o~ly a small amount thereof, for the solubility of wa-
ter-containing alcohols is particularly limited in these
types o~ gasoline.
As has been mentioned in the state of the art, there
3~ are used short-chain, straight-chain or branched aliphatic
alcohols as a further mixing component for gasolines.
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These alcoho1s which have generally of from 1 to 5 carbon
atoms, are preferably methanol, ethanol or mixtures
thereof.
The quantity of alcohol is more or less great, depen-
ding on the intended use. It is generally in the range offrom 5 to 50 weight %, preferably 10 to 30 weight ~, calcu
lated on the weight of the gasoline-alcohol mixture.
The quantity of water which may be contained in
gasoline-alcohol mixtures may vary within wide limits. It
is generally in the range of from 0.01 to 10 weight %,
preferably of from 0.05 to 1 weight %, calculated on the
weight of the gasoline-alcohol mixture.
The boric acid esters to be used according to the
present invention are prepared by reacting boric acid with
said alcohols.
To this end, boric acid, preferably orthoboric acid,
and the alcohol, preferably an alcohol of the formula
RO-(R10)x-H wherein R,R1 and x are defined as in formu-
la I, are reacted at a molar ratio of from 1 : 0.5 to
20 1 : 6, preferably 1 : 1 to 1 : 3, in a recipient equipped
advantageously with a stirrer and optionally with a reflux
condenser, with removal of the reaction water obtained.
The reaction temperature is generally from 50 to 150C,
preferably from 110 to 140C.
Removal of the reaction water to the desired level is
done preferably continuously in the course of the reaction
in a vacuum, for example a water jet vacuum, of from about
500 to 1500 Pa generally. The water may be removed alter
natively by means of an inert solvent forming an azeotropic
mixture with water7 for example toluene, xylene, rnethylene
chloride and the like.
Upon completion o~ the reaction, the solvent optio-
nally used is removed ~rom the reaction product by usual
distillation and, if a further purification should be
necessary, the reaction product is stripped in vacuo under
a pressure of from abo~t 1 to 500 Pa suitably at a tempe-
rature of ~rom 90 to ~50C.
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The preparation process described hereinbefore gene-
rally yield a mixture o~ different boric acid esters. An
appropriateselection of the reaction parameters, such as
molar ratio, temparature and degree of conversi.on (measu-
red on the quantitiy of the reaction ~ater), in the reac-
tion of the trifunctional boric acid with mono- to trifunc-
tional alcohols permits a controlled complete or partial
esterfication and the preparation of structurally tailor-
made boric acid esters or boric acid ester mixtures.
The gasoline mixtures according to the invention may
contain further advantageous components, for example the
anti-knock agents and antioxidants that are usal for
gasolines.
The preparation of the gasoline mixtures according to
the invention takes place by simply mixing the individual
components, for example at room temperature in a recipient
equipped with a stirrer.
The gasoline mixtures accordirlg to the present inven-
tion are distinguished by a low cloid point, even in the
case of high water contents and at low temperatures, that
means they do not separate into phases even at relatively
low temperatures. The boric acid esters according to the
invention act as water acceptor and as emulsifier. They
bind water not only by physical forces, like the known
emulsifiers and solubilizers, but also chemically. The
unexpected advantageous effect of the boric acid esters
proposed by the present invention can be seen moreover by
the fact that homogeneous gasoline-alcohol mixtures and
gasoline alcohol-water mixtures can be prepared by using
comparatively small amounts thereof. The boric acid
esters have moreover an anticorrosive action so that an
addition of anti-corrosives which must be suitable for
gasoline-alcohol mixtures, which frequently involves
problems, can be dispensed with.
The invention is illustrated by the following
examples.
~ 7 ~ HOE 80/F 925
Gasoline mixtures according to the invention were pre-
pared by mixing the fo].llowing components and the cloud
point (C) of the resulting mixtures was measured.
For comparative reason there was measured the cloud
point of the following mixture.
COMPARATIVE EXAMPLE
The comparative gasoline mixture consisted of
85 weight parts of gasoline having a boiling range of
from 40 to 200C,
15 weight parts of methanol and
0.25 weight part of water.
This mixture showed to have a cloud point of -2C.
_XAMPLE 1
a) 85 weight parts of gasoline having a boiling range
of from 40 to 200C,
b) 15 weight parts of methanol,
c) 0.25 weight part of water and
d) 1.5 weight part of boric acid ester of the formula
B~(O~isoC4Hg)3.
The cloud point of this mixture was found to be -32.8 C.
EXAMPLE 2
a) 85 weight parts of gasoline having a boiling range
of from 40 to 200C,
b) 15 we~ght parts of methanol,
. c) 0.25 weight part of water and
d) 1.5 weight part of boric aci.d ester of the formula
R-to-isoC8H17)3.
The cloud point of this mixture was found to be -28.5C.
EXAMPLE 3
a) 85 weight parts of gasoline having a boiling range
of from 40 to 200C,
b) 15 weight parts of methanol,
~ ~ ~ OE 80/F 925
c) 0.25 weight part of water and
d) 1.0 weight part, of boric acid ester of the formula
B-(OCH3)3.
The cloud point of this mixture was found to be 11.9C.
EXAMPLE 4
a) 85 weight parts of gasoli.ne having a boi.ling range
of from 40 to 200C,
b) 15 weight parts of methanol,
c) 0.25 weight part of water and
d) 1.5 weight part of boric acid ester of the formula
. B-(OCH2CH20CH3)3.
The cloud point of this mixture was found to be -15.9C.
EXAMPLE 5
,
a~ 85 weight parts of gasoline having a boiling range
of from 40 to 200C,
b) 15 wei.ght parts of methanol,
c) 0.25 weight part of water and0 d) 1.0 weight part of boric acid ester of the formula
B_(ocH2cH2-ocH2cH2ocH3)3-
The cloud point of this mixture was found to be -13.5C.
XAMPLE 6
a) 85 weight parts of gasoline having a boiling range
of from 40 to 200C,
b) 15 wei.ght parts of methanol,
c) 0.25 weight part of water and
d) 0.5 weight part of boric acid ester of the formula
B--(O-iso-C9H19)3.
The cloud point of th.is mixture was found to be -12.3C.
E MPLE
a) 85 wei.ght parts of gasoline having a boiling range
of from 40 to 200C,
b) 15 weight parts of methanol,
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c) 0.25 welgh~ part of water and
d) 1.5 weight part of boric acid ester of the formula
B-(O-iso-C13H27)3.
The cloud point of thiC mixture was found to be -26.0C.
EXAMPLE 8
) 85 weight parts of gasoline having a boiling range
of from 40 to 200C,
b) 15 weight parts of methanol,
c) 0.25 weight part of water and
d) 0.5 weight part of boric acid ester of the formula
B-(OCH~Hg)3.
The cloud point of this mixture was found to be -12.9C.
