Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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GLYOXAL AS FUEL ADDITIVE
BACKGROUND OF THE INVENTION
1. Field of the Invention:
The present invention relates to fuef additives for internal combustion device
fuels,
particularly for gasoline and diesel engine fuels and fuel oils, which provide
a reduction
in pollutant emissions and coke deposits, improved efficiency, smoother
running of the
engine as well as a cleaning effect on the combustion chamber of the engine.
2. Description of the Prior Art:
Fuels for the internal combustion engines and turbines damage the environment
due
to, among other factors, the incomplete combustion in the engines, of
hydrocarbons,
carbon monoxides and nitrogen oxides. Metal-ceramic catalytic converters are
known
to reduce this damage by means of catalytic afterburning of the engine
exhausts. The
combustion energy released thereby cannot be used, however, for the primary
process
of energy production in the engine. Also, the efficiency of the catalytic
converter can
decrease over time leading to increased pollutant emission levels. The
addition of a
fuel additive, prior to the combustion stage, would have distinct advantages
over, or in
addition to the traditional methods for handling exhaust emissions.
The amelioration of fuel qualities by the addition of diverse substances is a
familiar
technique in the prior art. Thus, e.g., according to DE-PS 582 718, heavy
metal salts,
namely, cooper, nickel, cobalt, zinc and chromium salts, as well as the
condensation
products of amines with compounds which contain one or more oxygen groups in
addition to a carbonyl group, are added to the fuel in order to improve its
knock
resistance. In DE-PS 448 620 and DE-PS 455 525, fuels are described which have
a
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content of iron carbonyl or nickel, cobalt and/or molybdenum carbonyl.
However, these
techniques have not become popular, because the use of metal carbonyls causes
a
metal oxide deposit in the combustion chamber of the vehicle and are toxic. DE-
PS 801
865 teaches the use of fuel additives, which can be toluene, benzene, acetone,
trichlorethylene or isobutyl alcohol, besides the metal carbonyls, although
the
fundamental drawback of metal oxide deposits in the combustion chamber remains
the
same. DE-AS 1 221 488 describes fuel additives consisting of
methylcyclopentadienyl
manganese tricarbonyl, lead tetraethyl or other organometallic compounds and
organic
compounds having two ester groups. The following organic fuel additives are
also
recognised as constituting a part of the state-of-the-art: a mixture of an
aromatic amine
and a polyalkyl phenol, as shown in DE-PS 845 286; tretaarylhydrazine,
diarylnitrosamine and triarylmethyl derivatives from DE-PS 505 928; aldehydes,
quinones and ketones from DE-PS 612 073; ketones of formula R-CO-R', wherein R
represents a ring radical and R' an aliphatic radical with at least 6 C-atoms,
from United
States Patent No. 2,100,287; hydroquinone in a benzene solution from DE-PS 486
609; ether derivatives from DE-PS 703 030; alcohols from DE-PS 843 328;
condensation products of alkylene oxides and afkylphenols from DE-PS 19 37
000;
anthracene derivatives from Unites States Patent No. 1,885,190 and 1.4-dialkyl-
arylamino-anthraquinone from EP 09 095 975 B1.
United States Patent No. 1,973,475 describes a method for oxidation of fuels
with air or
oxygen at elevated temperatures, possible in the presence of a catalyst. DE-PS
699
273 discloses a method of dehydrogenation of non-flammable oils from the
boiling
range of diesel oils in inflammable oils with oxidising agents such as air or
oxygen,
ozone, peroxides, chromic acid or nitric acid at 150°-350°C,
possibly at elevated
pressure and preferably in presence of a catalyst. The ozonization of fuels is
also
described in DE-PS 324 294 and DE-PS 553 943. According to DE-PS 324 294,
ozonides such as ethylene ozonide, or a mixture of one of the conventional
fuels with
an ozonide, are added to the internal combustion engine. The drawback of the
method
is the instability of the ozonides, so that when kept for a lengthy time the
availability of
oxygen carriers is necessarily variable, apart from the problems of
environmental
pollution, which were not known at the time. According to DE-PS 553 943, a
mixture of
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hydrocarbons is ozonized under pressure in the presence of an oxygen carrier,
such as
turpentine oil, and slight amounts of ignition-promoting substances.
The procedures described in the patents above are not commercialized. The
described
substances are partially toxic, carcinogenic or the procedures are too
expensive. They
do not add any value in the petrochemical market.
In DE 1144971 there is shown the use of leadtetraethyl in addition to
monocarbonic
acids, to achieve boosting of the octane number. In DE 1271455 diketons are
patented
in combination with leadtetraethyl as antiknock-substances. Aliphatic
polyethers with
the general formula R-(O-X)"-O-R') are described in the United States Patent
No.
2,655,440 as additives increasing the cetyl number. DE 19527423 A1 describes
the
ozonisation of gasoline containing benzene, wherein together with other
oxidation
products glyoxal is formed. This process has the disadvantage, that
ozonisation
apparatus in a refinery are unusual and expensive.
SUMMARY OF THE INVENTION
The present invention has as its object the reduction of the emission of
pollutants and
the consumption of fossil fuels and their derivatives. The pollution of
environment by
the incomplete combustion sequence in combustion engines with expulsion of
carbon
monoxide, unburned hydrocarbons, as well as nitrogen oxide is sufficiently
well known.
Subsequent use of catalytic converters, and the Pike, are a stop gap measure,
at best.
Thus, preference should be given to an optimization of the combustion process
in the
immediate energy-supplying step.
The present invention accomplishes this purpose in a fundamental, technically
feasible
and effective mode and manner.
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In the present invention, pollutant emissions from combustion engines are
reduced by
the addition of glyoxal and glyoxal derivatives and adducts in aqueous
solution to-the
fuel supply to the combustion engine. Preferably, different acetals and
hemiacetals or a
mixture thereof obtained by the acetalization of glyoxal are added to the
fuel.
Additional objects, features and advantages will be apparent in the written
description
which follows.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a graph of the reduction in emission of CO achieved through the
use of
the additives of the invention with the engine at idle;
Figure is a similar graph of the reduction in emission of
2 HC at idle;
Figure is a similar graph of the reduction in emission of
3 CO at increased idle;
Figure is a similar graph of the reduction in emission of
4 HC at increased idle;
Figure is a graph of diesel emission of carbon particles
with time showing the
effects of the additives of the invention in reducing such emissions; and
Figure 6 is a graph of the reduction in emission of NOX with time showing the
effects of the additives of the invention in reducing such emissions.
DETAILED DESCRIPTION OF THE INVENTION
Applicant's EP94/02052, now issued as United States Patent No. 5,762,655,
describes
a technique for optimizing the combustion process in internal combustion
engines. In
that process, the ozonization products of gasoline and diesel fuels provide a
catalytic
effect on the combustion process with the result that unburned hydrocarbons
and
carbon monoxide are reduced drastically. On one hand, this technique has the
advantage that it is highly effective. On the other hand, however, it has the
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disadvantage that it is relatively costly since an ozonization system has to
be integrated
into the respective refinery plants supplying the combustion fuel.
The present invention has as its object to provide the same benefits achieved
with the
previously described ozonization process, but without the attendant expense.
fn the present invention, glyoxal in aqueouss solution is used as a basic
product for fuel
additives in order to obtain a reduction of pollutant emission. Glyoxal is
obtained by
oxidation from glycol in aqueous solution in industrial scale techniques.
Here, glyoxal
can be added to the fuel either together with flammable emulsifiers or in a
chemical
compound as described below. Compared to previous suggestions, this technique
has
the advantage that, here, a product can be used which is produced on an
industrial
scale and, therefore, economically and easily available; furthermore, the
substances
described herein are relatively stable in storage compared to the oxides which
arose in
the ozonization process of previous techniques and which drastically reduced
the
storage stability.
One factor to be considered in the practice of the present invention is the
relative
solubility of glyoxal in water when it is added to gasoline. It has been
discovered,
however, that a usual 40% glyoxal solution, together with a usual emulsifier
consisting
of esterified aliphatic compounds, can be mixed surprisingly well with
gasoline if
polyethyleneglycol is added. Thus, for example, 10 milliliters of a 40%
glyoxal solution
plus 10 milliliters of a standard, off the shelf emulsifier based on
esterified aliphats (i.e.
"Ecocool-ACC" of the firm Fuchs (.ale) , as well as 10 milliliters
polyethylenegfycol can
easily be mixed with 500 milliliters gasoline. Here, after thorough mixing for
some time,
a slightly cloudy gasoline-additive-emulsion is obtained. If 10 milliliters
methyltertiarybutylether are added hereto, the mixture becomes completely
clear
afterwards. It is, however, very important here that, first, the glyoxal in
aqueous
solution, the emulsifier and the polyethyleneglycol are very thoroughly
homogeneously
mixed and then, the mixture added to the gasoline. The gasoline-additive-
emulsion
obtained by this process is quite stable in storage. In high gasoline
quantities, there is
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no longer any separation of phases. Aqueous glyoxal solution or concentrated
glyoxal
can also be added to "Aquazole" (trade name of ELF Aquitaine) as it is
described in
Focus 22/1999, page 188-189.
In the practice of the method of the invention, the addition of 500
milliliters of the
gasoline-additive-emulsion to 40 liters gasoline has been found sufficient to
obtain a
reduction of unburned hydrocarbons of 95% in vehicles with catalytic
converters at
increased idle and at idle after the cars have been driven five kilometers in
urban
driving. Usually, carbon monoxide can no longer be identified under these
conditions.
Also a reduction of the emission of nitrogen oxides (NOX) of approximately 90
% has
been obtained.
The tables that follow provide the results of a statistical survey on the
results of tests
with gasoline to which the above-described additive was added. As only 4 grams
glyoxal were mixed into 40 liters of gasoline, it can be calculated that
giyoxal shows its
effectiveness as a homogeneous catalyst at the ppm-level. Furthermore, the
quantity of
water of 10 milliliters per 40 liter gasoline is so low that there is no
danger of corrosion
for the engine. Any and all components of the described additive are flammable
and
nontoxic so that toxic side effects can be excluded.
In diesel fuel, the aqueous glyoxal solution as described above is even more
easily
soluble than in gasoline. Here, a milky cloudy fuel mixture is obtained, the
phase
mixture of which is considerably more stable. Fuels to which this additive
have been
added produce in diesel engine vehicles at idle and at increased idle (10 %
according
to ECE-standard) an average reduction of the particulate emission or coke
deposit of
30 to 40% and of nitrogen oxides of 20%.
Tables I and II below as well as the graphs shown in Figures 1-5 provide the
results of
emissions tests using the glyoxal solution additive of the invention:
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TABLE I
Reduction in emission through glyoxal emulsion in
gasoline (at idle) n=22
Date CO before CO after HC before HC after
07.03.1998 0,01 0 34 5
07.03.1998 0 0 34 5
07.03.1998 0,01 0 79 2
07.03.1998 0 0 8 7
06.26.1998 0,01 0 6 3
06.26.1998 0 0 21 10
06.26.1998 0 0 5 7
06.26.1998 0 0 6 9
05.22.1998 0 0 5 3
05.22.1998 0 0 9 3
05.22.1998 0,02 ~ 0 54 10
05.22.1998 0,02 I 0,01 20 11
04.08.1998 0,1 0 111 6
03.25.1998 0 0 22 29
03.25.1998 0 0 6 4
03.23.1998 0 0 6 2
03.23.1998 0,01 0 16 0
03.23.1998 0 0 4 4
03.18.1998 0,07 0,09 34 I 13
03.05.1998 0,04 0 42 1
03.05.1998 0,04 0 57 7
without date 0,02 0,01 ~ 15 ( 9
'' average value 0,02 0,01 27,00 ' 6,82
standard deviation0,03 0,02 27,67 6,06
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Table II
Reduction in emission through glyoxal emission in
gasoline (at increased idle) n=22
Date CO before CO after HC before HC after
07.03.1998 0,26 0 99 9
07.03.1998 0,02 0 56 5
07.03.1998 0,06 0 27 5
07.03.1998 0 0 14 11
06.26.1998 0 0 5 2
06.24.1998 ~ 0 10 12
06.24.1998 0 -. ~,1 10 15
06.24.1998 0,03 0,01 8 9
05.22.1998 0 0 5 2
05.22.1998 0 0 12 2
05.22.1998 0,03 0 13 7
05.05.1998 0 0 10 12
04.08.1998 0,12 0 41 6
03.25.1998 0,03 0,01 17 13
03.25.1998 0,01 0,02 8 5
03.23.1998 0 0 8 5
03.23.1998 0,1 0 27 0
03.23.1998 0 0 11 6
03.18.1998 0,29 0,05 13 17
03.05.1998 0,13 0 24 3
03.05.1998 0,01 0 16 8
without date 0,05 0,04 9 5
average value 0,05 0,01 20,14 7,23
standard deviation 0,08 0,02 21,49 4,56
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Conditions:
All cars were BMW Type 5 (525 or 528)
measuring equipment: Digas AVL Type 465 (Graz, Austria)
Sensor AVL Type 1554
The Figures 1 to 4 graphically present the average pollution emission values
of a
stationary engine (BMW Type 5 (525 or 528)) of tables I and II that is
operated with a
conventional gasoline before and after application of a glyoxal emulsion
according to
the present invention.
Fig. 1 shows the carbon monoxide (CO) values in %vol at idle. After
application of an
aqueous glyoxal emulsion, containing 4 g glyoxal in 10 ml water to 40 I
gasoline fuel,
which corresponds to a ratio additive to fuel 1:10000, i. e. 0,1 %°vol
a reduction of 50
from 0,02 %vol to 0,01 %vol CO is obtained. Fig. 2 shows the emission values
of
hydrocarbons (HC) in %vol,ppm under equal conditions. Here after the
application of
the additive a reduction of nearly 75 % from 27,00 %vol,ppm to 6,82 %vol,ppm
is
obtained.
Fig. 3 shows the carbon monoxide value at increased idle (10 % according to
ECE-
standard) under the same quantitative conditions, concerning the ratio
additive to fuel.
With conventional gasoline fuel a value of 0,05 %vol is measured. After adding
the
additive this value decreases to 0,01 %vol, which is a reduction of 80 %. Also
the
hydrocarbon value, shown in Fig. 4, decreases from 20,14 %voi,ppm to 7,23
%vol,ppm
at increased idle.
The reduction of the emission of carbon particles with time of a diesel fuel
engine, type
AUDI diesel 5 cylinder, 140 hp (no oxidationkat) after the application of an
additive,
according to the present invention is shown in Fig. 5. Said additive
comprising 5,0 ml
1,1,2,2-tetraethoxyethane on 10,3 I diesel fuel, which is a ration of additive
to fuel of
1:2060, i. e. 0,485 °/°°. After adding the additive the
value of emitted carbon particles
decreases rapidly from 27,56 carbon particles m'' to 3,78 carbon particles m''
within
21 min, a reduction of 86,3 %. After another 91 min the value reaches 0,82
carbon
particles m'', which is a total reduction of emitted carbon particles of 97 %.
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Finally Fig. 6 shows the reduction of emitted nitrogen oxides (NOX) in
%vol,ppm with
time in the exhaust gas of an gasoline engine, type Ford Van V6 (1996), at
increased
idle with 1300 to 1370 RPM. Without the aditive, according to the invention a
value of
340 %vol,ppm is measured. After the application of 0,86 %° (= 50,0 ml)
1,1,2,2-
tetramethoxyethane (TME) the value decreases after approximately 25 min to
135 %vol,ppm and after another 15 min the value drops to 37 %vol,ppm, which is
a
overall reduction of nearly 90 %.
In an especially preferred embodiment of the present invention, instead of
glyoxal in
aqueous solution, acetals and hemiacetals of glyoxal are added to the fuel
mixture.
Acetal formation is a well known process in organic chemistry and is
described, e.g., in
"Organic Chemistry", Morrison and Boyd, 2nd Ed., 0969, page 633 et seq., and
is used
to describe compounds of the general type RCH(OR')Z. Far example, in simplest
terms,
acetaldehyde reacted with methanol in the presence of HCl yields acetaldehyde
diethyl
acetal (Acetal). Similarly, alcohols will be added to aldehydes to produce
"hemiacetals"
in a reaction catalyzed by both acids and bases. A hemiacetal in the presence
of an
alcohol and an acid catalyst is converted to an acetal. See also, "Organic
Chemistry",
Holt, Rinehart and Winston, 1964, pages 308-310.
Such acetals and hemiacetals can be prepared according to the state-of-the-art
as
described above. A particular way to manufacture this products is described as
follow:
660 grams of molecular sieves 4 A is placed in a column reactor. A mixture of
600
grams glyoxal trimmer hydrated and 180 grams of amberlist 15 (ion-exchange
resin) is
filled on top of the molecular sieve in that column. The content of the column
is heated
up to 80°C. Then for example methanol or ethanol is pumped through the
ion exchange
resin as a catalyst and through the molecular sieve (water scavenger). The
ratio of
methanol to glyoxal is 4 mol, in the case of ethanol 12 mol.
During 16 hours the desired compound is obtained. The purification and the
separation
of the desired compound from the solvent occurs by distillation. Methanol and
ethanol
are removed at 40°C and 22 torr. The purification occurs at 58°C
and 20 torr.
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The acetals and hemiacetals used in the present invention are obtained by the
acetalization of glyoxal with linear and/or branched alcohols having C,-C,6
carbons
' such as methanol, ethanol, propanol, butanol, isopropanol, isobutanol,
amylalcohol,
with diols such as ethane diol, propane diol, butane diol, octane diol,
neopentylglycol as
well as triols such as glycerol. Furthermore mixtures of such mono-, di-, and
trialcohols
can be applied. Thus, the acetals and hemiacetals used in the present
invention can
have various alkoxy groups at the -CH2-CHZ-; unit of glyoxal. Thus different
physical
properties of the acetals and hemiacetals can be adjusted by the variation of
the alkoxy
groups.
While the invention has been shown in only two of its forms, it is not thus
limited but is
susceptible to various changes and modifications without departing from the
spirit
thereof.
