EP1656436A1

EP1656436A1 - Microemulsions and use thereof as a fuel

Info

Publication number: EP1656436A1
Application number: EP04766373A
Authority: EP
Inventors: Reinhard Strey; Axel Nawrath; Thomas Sottmann
Original assignee: Universitaet zu Koeln
Current assignee: Universitaet zu Koeln
Priority date: 2003-07-29
Filing date: 2004-07-29
Publication date: 2006-05-17
Also published as: US7977389B2; US20070028507A1; WO2005012466A1; DE10334897A1

Abstract

The invention relates to bicontinuous microemulsions and to the use thereof as a fuel, combustion or heating fluid. Said fuels permit an increased efficiency of internal combustion systems and heating installations of any type and, simultaneously, a minimised emission of pollutants, associated with combustion, to be obtained.

Description

Microemulsions and their use as fuel

The invention relates to microemulsions which have a characteristic nanostructure of alternating continuous hydrophilic and hydrophobic domains. Such microemulsions serve as fuels that allow combustion of unprecedented levels of pollution and efficiency.

Background of the Invention

The combustion of fossil, crude oil-based fuels is a problem in many respects. World oil consumption is currently around 3.5 billion t, with around 90% being used as fuel and heating fuel. Auto fuels, power station fuels, marine fuels and aircraft fuels make up the largest share.

However, if oil consumption remained the same, global oil reserves would only last about 50 to 100 years, so that there is a very great need for more efficient combustion processes.

More efficient combustion processes are also required to reduce the CO ₂ emissions as a combustion product. In the earth's atmosphere, C0 ₂ reflects the heat radiation emitted by the earth's surface. The high emissions of C0 ₂ are therefore the main cause of the greenhouse effect.

Another problem with the combustion of conventional fuels is the emission of pollutants, which cannot be completely eliminated by new injection and combustion technologies as well as fuel additives.

Especially in motorized road traffic, air pollution from pollutants such as nitrogen oxides (NO _x ), carbon monoxide (CO), hydrocarbons (HC) and soot particles (PM) as well as precursors that negatively affect the ozone balance is a major problem. These problems can be solved by modern Exhaust gas aftertreatment technologies such as automotive exhaust gas catalysts can only be partially solved. This means that diesel can be burned more efficiently than other fuels, but it also leads to considerable soot particle formation. For technical reasons, no exhaust gas aftertreatment is currently used to remove NO * in diesel vehicles.

Air pollution is also a problem that has not yet been solved.

To use fossil energy sources more efficiently, the development of improved combustion technologies such as improved fuel injection in internal combustion engines. However, improved combustion processes often have worse

Pollutant emission behavior. Due to thermodynamic laws, the efficiency of internal combustion engines is increased by increasing the combustion temperature. However, increasing the combustion temperature often leads to increased pollutant emissions, especially NO _x .

One possibility for simultaneously improving the combustion efficiency and the pollutant emission behavior is the use of special fuels, in particular fuels, which consist of a mixture of an aqueous and a non-aqueous phase, for example water in oil (W / O) emulsions. Such fuels allow an efficient combustion process despite comparatively low combustion temperatures.

A key point of the use of these special fuels is the positive effect of the addition of water on the combustion by the steam engine effect of the evaporating water. This means that water is converted from the liquid to the gaseous state and drives the piston in addition to the combustion gases. Due to the evaporation enthalpy, the evaporation of the water reduces the temperature in the combustion chamber, thereby reducing the pollutants NO _x and CO, HC and PM ("particular matter", soot particles) in the exhaust gases. The use of oil and water emulsions in various combustion processes has been tried and tested many times. The main disadvantage of such emulsions is their instability, moreover their water content is not variable and only very small.

Formulations are known which are described as kinetically stabilized microemulsions. The use of thermodynamically stable microemulsions has also been described. These are non-optimal microemulsions (W / O) from water-swollen micelles present in the fuel. These are microemulsions with exactly one continuous phase. Therefore, the proportion of water in the previously known fuel microemulsions is rather small and is often not more than 20%. Microemulsions with a high proportion of water often have high or expensive proportions of emulsifiers. Furthermore, many formulations contain large amounts (up to 20%) of alcohols.

Most known water fuel mixtures have only water-in-oil micelles as microstructuring and do not represent optimal, bicontinuous microemulsions. Many inventions have the problem that only a little water can be emulsified. In addition, to optimize combustion, there is no technology to adjust the water content of the mixture as desired. If one takes a closer look at the composition of the known waterfuel mixtures, it is often not waterfuel emulsions with alcohol, but only alcohol fuel emulsions with small amounts of water. The high fugacity of ethanol often creates the additional problem that ethanol, but also other more volatile substances, are increasingly forced out of the mixture into the gas phase.

No. 4,744,796 describes water / fuel microemulsions with diesel, gasoline, heating oil and kerosene as the oil component, which are stable in a single phase and clear with a high salt tolerance over a wide temperature range of a maximum of -10 ° C. to + 70 ° C. The proportion of the aqueous component consisting of water and / or methanol is 3 to 40%. As a cosurfactant, tert-butyl alcohol (TBA, 1-20%, with methanol up to 30%) is added to one or more cationic, anionic, amphoteric and nonionic surfactants (2-20%). Betaines with different carbon chain lengths (11-17) are used as amphoteric surfactants and ethoxylated alcohols (Ej), alkylphenols and carboxylates as nonionic surfactants used. Quaternary ammonium salts are used as cationic and fatty acids as anionic surfactants. These water / fuel microemulsions are not optimal, non-bicontinuous O / W microemulsions for this purpose. Furthermore, TBA is used as a mandatory cosurfactant in this patent.

No. 4,158,551 describes an emulsion of gasoline, water and nonionic surfactants in order to minimize environmentally harmful exhaust gases during combustion. The mixture contains up to 22% water and is stabilized by 1-3.5% surfactants. The surfactants are essentially ethoxylated alkylphenols with 1.5-30 mol ethylene oxide per mol nonylphenol. However, such an emulsion is thermodynamically unstable.

No. 6,302,929 describes water-rich fuels which, in contrast to most other known emulsions, are based on two-phase water-continuous (O / W) emulsion systems. These fuels have the advantage over pure hydrocarbons that they are not flammable outside the combustion chamber. 20 - 80% water can be emulsified in the mixtures described. The emulsions also contain 2-20% alcohols, small amounts (0.3-1%) of non-ionic surfactants (QE _j , alkyl glucosides, Igepal CO-630), and minor amounts of polyorganosiloxanes. The fuel component is petrol, kerosene, diesel, synthetic and biological fuels, which can be burned more effectively than the pure hydrocarbons. The high water content lowers the combustion temperature so much that the emission of pollutants is reduced (CO: -50%). However, the preparation of the mixtures described is difficult to carry out and the combustion composition should vary considerably in the application. In practice, the motors for two-phase mixtures must also be modified more ("rotary engines") than for single-phase mixtures.

EP 0475620 describes temperature-insensitive diesel, gasoline and kerosene microemulsions and their low-pollutant combustion. The mixtures contain up to 30% water, which can be partially or completely replaced by methanol, ethanol or propanol. In addition to a variety of Additives (for example ammonium nitrites, nitrates, and halates as well as halogen acids and organic compounds) to improve the combustion parameters are described in a wide range of emulsifier systems which are used as combinations of at least two different surfactants. In addition to numerous ionic surfactants (C ₈ -C ₃ o ~ chains with and without branching / ring) with various head groups (including alkali metals, -S0 ₃ H, -NH ₃ as well as alkylated, alkanoylated, ethoxylated or sulfonated ammonium) there are also a number of nonionic surfactants (for example E _j , Igepale, ethoxylated alkylphenols) used. A distinction is made not between ionic and non-ionic, but rather according to hydrophilic and lipophilic surfactants (phase status 2 or 2 at T = 20 ° C, Φ = α = 0.5 and γ = 0.02). A wide range of cosurfactants (medium-chain alcohols, glycol ethers and ethers) is also used. Single-phase, transparent microemulsions are described. However, single-phase microemulsions with 2% surfactant are optically cloudy, so it can be assumed that the optically clear microemulsions must contain more than 10% surfactant. Such mixtures with a low water / surfactant ratio are not sufficiently efficient for economical use.

No. 5,669,938 describes single-phase W / O emulsions made of diesel and 1-40% water and surfactant for reducing pollutants (CO, NO _x , HC, soot, PM). The central characteristic is the use of organic alkyl nitrates. Linear hydrocarbons with a chain length of 5 to 10 carbon atoms and branched hydrocarbons, in particular the 2-ethylhexyl radical, serve as alkyl radicals.

No. 4,451,265 describes single-phase, clear fuel / water microemulsions which have high stability at low temperatures. The existence of W / O micelles is suspected in the unexplained microstructure. The blends consist of diesel (34-99%), water (OJ-6%), alcohol (0.5-42%) and a surfactant system (0.5-58%). Above all, ethanol, but also methanol and propanol are used as alcohols, which represent the much larger proportion of the aqueous phase (Ψ _Eth = 70-95%). The water content in the emulsion is limited to a maximum of 6%. Microemulsions with technical surfactants are described which have a hydrophilic N, N-dimethylethanolamine head and have a hydrophobic fatty acid residue with a carbon chain length of 9 to 22 atoms, especially fatty acids of soybean.

US 4,451,267 describes microemulsion fuels from vegetable oils. Soybean oil, but also many other oils, such as rapeseed oil, are primarily used as vegetable oils. The aqueous component of the low-water microemulsions consists largely of methanol, ethanol or propanol Trialkylated amines with long-chain fatty acids are used as surfactants, which are supplemented by large amounts of butanol as cosurfactant (approx. 20%). W / O micelles are also assumed to be microstructuring here.

No. 4,002,435 describes W / O emulsions with gasoline which are stable in a single phase over a wide temperature range and are based on large proportions of alcohol (0.1-20%). Methanol, ethanol and isopropanol are used as alcohols. The emulsions contain only a little water (0.1-10%) and a mixture of organic oleate, linolate and stearate salts, oleic acid and phenolated and ethoxylated fatty alcohols.

US 4,599,088 describes petrol emulsion fuels with 2-10% alcohol, such as methanol, ethanol, isopropanol or TBA. However, the formulations only contain 0.1-0.5% water. The blends contain 0.1-3.0% surfactants, and exclusively non-ionic alkylphenols and QE surfactants, where i = 9-24 and j = 6-10. The mixtures are referred to as single-phase microemulsions of the type W / O (micelles). However, only a little water can be dissolved in them. Larger additions of water lead to a water excess phase in the fuel tank.

No. 5,104,418 describes microemulsion systems composed of water, diesel, glycolipid (surfactant) and aliphatic alcohols (cosurfactant). The microemulsions are stable single phase between 0 ° C and 80 ° C. The description includes glycolipids of the form AXR, where the hydrophilic surfactant heads A can be glucose, mono-, di-, tri- and tetra-saccharides. Saturated, mono- and polyunsaturated, linear and branched hydrocarbon chains with a carbon chain length of 10 to 24 atoms are mentioned as hydrophobic radicals R, which have the functional groups X = ether, ester, acetai and hemiacetal are bound to the surfactant head. The microemulsions are defined as a thermodynamically stable colloidal dispersion. Here too, with large diesel components (60-90%), the water components are very small at 1-10%. The cosurfactant content (butanol, pentanol, hexanol), on the other hand, is very large at 6.3-21%, the glycolipid content is 1.7-9%. US 5,259,851 describes similar water-fuel-glycolipid-cosurfactant microemulsions with the same glycolipids and similar mixing ratios. However, other cosurfactants, namely aliphatic diols, and in addition to diesel, gasoline, heating oil, kerosene and other oils are used here.

US 4,465,494 and EP 0058605 describe microemulsions of water, fuel (also heating oil), surfactant and additive (special alcohols and amines), which are between -20 ° C and + 100 ° C (sometimes only between -10 ° C and + 20 ° C ) are stable single-phase. In addition to 1-27% alcohol (methanol, ethanol, isobutanol and ethyl 2-hexanol), these mixtures contain only 1-10% water. Benzylamines and phenoxyalkylated organic acid salts (counterion: metal ion or organic base) of various carbon chain lengths are used as surfactants. The microemulsions are efficient with a surfactant content of 1-10%. In addition to a process for producing the microemulsions, the reduction of emissions when they are burned is also described. The emissions of CO are reduced by 80% and of NO _x by 75% based on 100 kilometers driven compared to conventional fuels.

No. 6,017,368 describes microemulsions which contain water, fuel, anionic and nonionic surfactants, unsaturated fatty acids, aliphatic alcohols and ethanol or methanol. They are water-in-oil micelles with a low water content of 1 to 10%. These microemulsions are stable over a wide temperature range, have a low viscosity and reduce pollutant emissions during combustion. In addition to diesel, petrol and heating oil are used as fuels. The proportion of water-soluble alcohols is 6 to 14% greater than the proportion of water. The water-insoluble alcohols (1 to 10%) have a carbon chain length of 5 to 9 atoms. The anionic surfactants used (2 to 10%) are based on unsaturated fatty acids neutralized with ammonium, for example from soybean oil. As non-ionic surfactants (1st up to 5%), only non-ethoxylated compounds are used, since according to US Pat. No. 6,017,368 ethoxylated compounds have poor combustion properties. Only 2,4,7,9-tetramethyl-5-decyne-4,7-diol is mentioned as a nonionic surfactant.

EP 1101815 describes diesel-water microemulsions which contain an emulsifier and an emulsifiable agent, in particular sorbitan monooleate and nonylphenol ethoxylate. However, the water content is limited to a small concentration range (100-145 parts water based on 1000 parts diesel).

WO 00/31216 and EP1137743 describe a diesel fuel composition consisting of diesel fuel, (water-containing) ethanol, a polymeric stabilizing additive, and optionally an alkyl ester of a fatty acid and / or an auxiliary solvent such as e.g. a short chain alkyl alcohol. However, the water content of the ethanol used is at most 5% by weight, based on the amount of ethanol in the mixture.

DE 10003105, WO 01/55282 and EP1252272 describe fuel-water emulsions in which an alkoxylated polyisobutene is used as the emulsifier. The emulsion preferably contains 10-25% by weight of water and 0.2-10% by weight of emulsifier.

The water content in the water / fuel microemulsions known to date is small. It is often no more than 5 to 20%, rarely up to 40%. Water / fuel microemulsions with larger amounts of water can only be found in very few descriptions, but then with uneconomically high amounts of emulsifier. Furthermore, many formulations contain large amounts (up to 20%) of alcohols (methanol, ethanol and sometimes also longer-chain alcohols).

Disadvantages of the emulsions and processes described are the low emulsion stability, the high, costly proportion of emulsifier or insufficient systematic knowledge of phase behavior and mechanisms when burning. However, these are a prerequisite for constructing an optimal formulation for optimal combustion.

Conventional water / fuel mixtures have water-in-oil micelles as microstructuring and do not represent optimal, bicontinuous microemulsions. Often, there is the problem that only a little water can be emulsified. To optimize combustion, there is often no technology to freely adjust the water content of the mixture.

Some conventional water / fuel mixtures are not water / fuel emulsions with alcohol, but only alcohol / fuel emulsions with small amounts of water. The high fugacity of ethanol creates the additional problem that ethanol, but also other more volatile substances, are increasingly being driven out of the mixture into the gas phase.

Summary of the invention

Microemulsions have now been found which, in contrast to known formulations, represent optimal, bicontinuous microemulsions. These microemulsions can be used as hydro fuels, have a characteristic nanostructure of alternating water and oil domains and prove to be fuels with unprecedented levels of pollution and efficiency. Such microemulsions allow water and conventional fuels to be mixed in any ratio, but are thermodynamically stable.

The present invention relates to:

(1) a bicontinuous single-phase microemulsion, consisting at least of an aqueous component (A), a hydrophobic component (B) and an amphiphilic component (C / D), the microemulsion having a continuous aqueous phase and a continuous hydrophobic phase and the hydrophobic component (B) contains one or more substances which can be used as motor fuels;

(2) a preferred embodiment of (1), wherein the amphiphilic component contains at least one nonionic surfactant (C); (3) a preferred embodiment of (2), wherein the amphiphilic component further contains at least one ionic surfactant (D), preferably a sulfur-free ionic surfactant (D);

(4) the use of the microemulsion as defined in (1) to (3),

(i) as fuel in internal combustion engines, preferably in

Reciprocating engines, rotary engines and turbine engines; and or

(ii) as fuel in thrust engines, preferably in jet engines,

Turbine jet and rocket engines; and or

(iii) as fuel in combustion plants, preferably in heating plants and

Steam generating plants; and or

(iv) in ignition procedures; and or

(v) in explosives; and

(5) a method for determining and optimizing microemulsions according to (1) to (3), comprising the steps

(i) determining the temperature variance and adjusting the temperature invariance of the single-phase microemulsion by adjusting the content of amphiphilic component (C / D), and

(ii) Adjustment of the water-oil ratio in the range of volume ratio oil to water-plus-oil 4-96 vol .-% of the hydrophobic component (B).

The essence of the present invention is the efficient solubilization of water in conventional fuels such as diesel, biodiesel, gasoline, super, kerosene and heating oil using low concentrations of novel emulsifier mixtures of residue-free burning surfactants, cosurfactants and other additives. In contrast to existing emulsions, these mixtures are characterized by their thermodynamic stability, electrical conductivity and their single-phase character, which over a wide temperature range, but at least between -30 ° C and + 95 ° C, preferably between -30 ° C and + 70 ° C. According to the invention, the combustion of the optimized hydro fuels shows a significant reduction in pollutant emissions. The emission of NO _x , CO, incompletely burned hydrocarbons (HC) and soot particles is significantly reduced compared to conventional fuels. The subject of the invention is and the more efficient combustion of hydro fuels compared to conventional fuels.

Brief description of the figures

Fig. 1: Freeze fracture electron micrograph of a bicontinuous microemulsion of equal amounts of water and n-octane, 5 wt .-% surfactant (Cι ₂ E ₅ ). The drawing illustrates the three-dimensionally connected shape of the surfactant film, which separates water and octane on a microscopic level.

Fig. 2: Temperature invariance of a microemulsion of water (A), diesel (B), Lutensol ® T05 (C), Lutensit ® A-BO (AOT) and ammonium carbonate (E). The diesel fraction φ was 91.5 vol .-% based on the sum of the volumes of water and diesel. The ratio of (D) to (C + D) was δ = 0.335 and the ratio of (E) to (A + E) was ε = 0.038 (similar to composition K-10, Ex. 2). Area "3": Area in which three phases coexist with one another (water excess phase, bicontinuous phase and oil excess phase); Area "2": Areas in which 2 segregated phases coexist; Area "1": area in which a single-phase microemulsion is present (bicontinuous phase); x-axis: ratio γ of (C / D) to total microemulsion in% by weight, y-axis: temperature T in ° C.

Fig. 3: Results of the combustion experiments on engine test bench I (see BspJOA). Component mixture K-1 was measured in the preferred composition (Example 2).

(a) Exhaust gas temperature

(b) fuel consumption in kg / h

(c) Fuel consumption in g / kWh

(d) efficiency η

(e) NO _x content of the exhaust gas

(f) soot particles (gray values) in FSN open circles (O): microemulsion; open squares (D): reference diesel; open stars (&): microemulsion, based on flammable components (without water). Fig. 4: Results of the combustion experiments on engine test bench II (cf. BspJOB). Microemulsions from water (A), diesel (B), Lutensol® T05 (C), either Lutensit® A-BO (AOT) or AOT (see Example JOB), and ammonium carbonate (E) were measured.

The samples in detail: (1) 8.70% by weight water, γ = 0.13; 4.35 wt% water, γ = 0.13; (3) 2.87% by weight water, γ = 0.13; (4) 2.25 wt% water, γ = 0.10; (5) reference diesel; In addition, various measuring points were measured in the range 9-27% water, γ = 0.10, some of which are shown here. Detailed information on the samples can be found in Example 10B.

(a) Exhaust gas temperature

(b) Fuel consumption (MVEG; European standardized norm cycle, in which a simulated route - e.g. city / country etc. - is driven according to EU Directive 93/116 / EC)

(c) NO _x content of the exhaust gas

(d) Soot particles (gray values) in FSN

Legend see Fig.3; filled square (EI): only surfactant in the fuel (no microemulsion).

Detailed description of the invention

In the following explanations, a distinction is made between emulsions and microemulsions.

"Emulsions" in the sense of the present invention are liquid dispersions of water in oil, which are stabilized by the presence of an emulsifier. The production process is characterized by extremely strong shear and an interfacial tension in the range of 1-10 mN / m. "Microemulsions" are formed spontaneously from the components, preferably from an aqueous component, a hydrophobic component and at least one amphiphilic component and possibly further additives, with gentle stirring. They represent nanostructured mixtures in which the water-oil contact is optimally shielded, with interfacial tensions in the range of 10 ^"4 -10 ^_1 mN / m. In the present application text, “bicontinuous” means that a mixture according to the invention consists of an aqueous and a hydrophobic phase which are separated from one another at the microscopic level by an amphiphilic film. It is therefore a structure with two continuous domains, namely an aqueous and a hydrophobic domain.

The term “aqueous component” denotes synonymously with the term “hydrophilic component” and the word part “water” in word combinations, which have “water-oil” as a component, water and water-soluble or water-immiscible liquids, in particular water and short-chain organic alcohols such as ethanol, methanol, n-propanol and isopropanol, butanol, ethylene glycol, propylene glycol, glycerin.

The term “hydrophobic component” denotes synonymously with the also used terms “fuel”, “fuel”, “oil” and the word part “oil” in word combinations which have “water-oil” as a component, hydrophobic liquids that are miscible with hydrophobic liquids , in particular fuels based on fossil fuels and fuels derived from renewable raw materials, especially diesel fuel, biodiesel (rapeseed methyl ester), petrol (petrol), super gasoline, kerosene, bunker C-oil and bio-oils (native oils, e.g. rapeseed oil, soybean oil, etc.) ,

The term “amphiphilic component” encompasses nonionic and ionic surfactants, cosurfactants and other amphiphilic compounds, as defined in more detail under groups C and D. The terms “emulsifier” and “surfactant” also used in the following text are, unless they are closer are to be understood as synonyms for this term.

“Alkyl derivatives” and “alkyl radicals” (synonymous with the word “alkyl” such as in “polyalkyl glucoside”) in the context of the present invention include linear and branched, saturated, mono- or polyunsaturated aliphatic hydrocarbon chains, aliphatic alcohols, fatty alcohols, oxo alcohols or carboxylic acids, preferably aliphatic alcohols, fatty alcohols or oxo alcohols. Thermodynamically stable, single-phase mixtures of an aqueous component (A), a hydrophobic component (B) and an emulsifier component (C / D) were found, in which the oil to water plus oil volume ratio can be freely adjusted within a wide range and the water content is variable. They have a bicontinuous microstructuring, a low water / oil interfacial tension, they are electrically conductive, they burn more completely than the corresponding pure oil components.

The mixtures are stable with little use of emulsifier over a wide temperature range, preferably from -30 ° C. to + 95 ° C., particularly preferably from -30 ° C. to + 70 ° C., very particularly preferably from 0 ° C. to + 70 ° C. The mixtures can contain additives (E).

The proportion of the amphiphilic component (C / D) in the microemulsions according to the invention is 0.5 to 20% by weight, preferably 0.5 to 15% by weight, particularly preferably 1-8% by weight, very particularly preferably 1 -5% by weight.

The object of the invention is to provide optimized and clean fuels which can be combusted with air as efficiently and completely as possible in relation to the hydrocarbon content made available, preferably exclusively to water and carbon dioxide. Emissions of NO _x , CO, incompletely burned hydrocarbons (HC), soot ("particular matter", PM) are to be prevented as far as possible and the consumption of fuel is to be reduced.

This object is achieved according to the invention in that bicontinuous, optimal microemulsions are used as fuel, and in that emulsifier systems which are adapted to each oil and consist of at least one nonionic surfactant, preferably in a mixture with at least one ionic surfactant, particularly preferably in the presence of cosurfactants ( longer chain alcohols, amphiphilic block copolymers, etc.) can be added to the mixture. The microemulsions according to embodiment (1) are thermodynamically stable, single-phase microemulsions, which preferably consist of water, industrial oils and technical emulsifier mixtures.

The oils used are diesel, biodiesel, bio-oil, petrol, super, kerosene and / or heating oil with water in an oil to water-plus-oil volume ratio φ = 0.04-0.99, preferably φ = 0.04-0, 96 used.

The thermodynamic stability of the microemulsions according to the invention is achieved by emulsifier systems adapted for each oil, which preferably consist of nonionic and ionic surfactants and cosurfactants, e.g. longer chain alcohols, amphiphilic block copolymers, etc. exist. In addition to their efficiency, i.e. their low mass fraction, the surfactants used have the advantage of burning without additional pollutant emissions.

Components which are not oil-soluble, e.g. Salts, glycerin, methanol and other cosolvents are added to help improve combustion.

According to the invention, the most favorable water content is set for the respective oil in order to optimally burn the oils as microemulsions with regard to pollutant emissions and energy yield. With minimal use of surfactants, optimal, bicontinuous and conductive microemulsions are formulated for every water-oil ratio. The composition of the microemulsion is selected so that it remains stable in a single phase between -30 ° C. to + 95 ° C., particularly preferably from -30 ° C. to + 70 ° C., very particularly preferably from 0 ° C. to + 70 ° C.

The microemulsions according to embodiment (2) consist of an aqueous component (A), a hydrophobic component (B) and an amphiphilic component (C / D; synonymous with an emulsifier mixture) of one or more nonionic surfactants (C) which additionally contain ionic surfactants ( D) and which preferably contains at least one ionic surfactant (D) (embodiment (3)). Optionally, salts and additives (E) can be added to the aqueous component (A). The aqueous component (A) of the microemulsions according to (1) consists of water, to which one or more water-soluble alcohols can optionally be added, preferably 0 to 50% by weight (based on A) of methanol, ethanol and / or bioethanol, 0 to 40% by weight of propanol and / or tert-butyl alcohol, 0 to 80% by weight of glycerin and / or ethylene glycol. It is particularly preferred to add one or more water-soluble alcohols in concentrations of the individual alcohols from 0 to 40% by weight (based on A), very particularly preferably in concentrations of the individual alcohols from 0 to 20% by weight. The total concentration of the alcohols in A is preferably 0 to 90% by weight, particularly preferably 0 to 30% by weight, very particularly preferably 0 to 20% by weight.

The hydrophobic component (B) of the microemulsions according to embodiment (1) consists of one or more of the substances selected from diesel fuel, biodiesel (rapeseed methyl ester), gasoline (petrol), super gasoline, kerosene, bunker C-oil and bio-oils (native oils, e.g. rapeseed oil , Soybean oil, etc.). Mixtures of these substances can be used in any mixing ratio as component (B). Diesel or a mixture of on the one hand diesel, gasoline or super gasoline with on the other hand bio oil and / or biodiesel in any desired mixture ratios is used. Diesel or a mixture of diesel and biodiesel or bio oil is very particularly preferred.

The nonionic surfactants (C), ionic surfactants (D) and salts and additives (E) can be used in pure form or in technical quality, preferably in technical quality.

Nonionic surfactants (C) in embodiment (1) and (2) are selected from one or more of the groups of linear or branched nonionic surfactants (Cl), surfactants with a core structure such as sugar surfactants (C-2), cosurfactants (C-3) and So-called “efficiency boost” (C-4), preferably from groups (Cl) and (C-2), particularly preferably from group (Cl), very particularly preferably from polyethoxylated and polypropoxylated alkyl derivatives of group (Cl). Sulfur-free nonionic surfactants (C) are particularly preferred. The group of linear or branched nonionic surfactants (Cl) includes polyethoxylated alkyl derivatives (C, E ₃ ) and polypropoxy alkyl derivatives (C, P _j ), soy lecithin, oleacate glycines, alkylphenol ethoxylates (PhE _j ), single or multiple alkylated polyethylene glycerides ( PEG) and polypropylene glycols (PPG), organic phosphoric acid esters, phospholipids and ethoxylated Tnglycende. C, E _j and QP- have C chain lengths of i = 4-30 and j = 1-20 hydrophilic units, preferably i = 8-24 and j = 3-16, very particularly preferably i = 10-20 and j = 3-10. The alkyl derivatives in C, E _j and C, Pj for the purposes of the present invention (definition s above) are preferably linear and branched, saturated, mono- or polyunsaturated fatty alcohols or oxo alcohols PhE _j have C chain lengths of i = 4-20 and j = 1-30 hydrophilic units, preferably i = 8-16 and j = 4-20, very particularly preferably i = 10-16 and j = 10-18. All PEG and PPG have C chain lengths with i = 4-30 C atoms, preferably i = 10-24, furthermore monoalkyl PEG or -PPG j = 1-20 have hydrophilic units, preferably j = 4-16, Dialkyl-PEG and Tπalkyl-PEG or -PPG j = 1-30 hydrophilic units, preferably j = 6-22, and polyalkyl-PEG or -PPG j = 1-40 hydrophilic units, preferably j = 8-32 PEG 300 diaurate, PEG 400 distearate, PEG 200 distearate and PEG 30 dihydroxy stearate are particularly preferred. Phospholipids contain C chains with a length of i = 4-30 carbon atoms, preferably i = 8-24, particularly preferably i = 12 -20. Phospholipids which are used with very particular preference are made from technical fatty acids or phosphohpides and / or contain naturally occurring fatty acids with carbon chain lengths of l = 12-20.

The group of surfactants with core structure such as sugar surfactants (C-2) includes mono- and polyalkylglycosides (C, Z _j ), especially alkyl glucosides (C, G _j ), (poly) alkyl sorbanes (C | S ₃ ), alkyl maltosides (C, M _:) , Alkyl lactosides and their ethoxylated and propoxylated derivatives The C chain length in the alkyl radicals of these compounds is i = 4-30, preferably i = 8-24, particularly preferably i = 12-20 They contain j = 1-10 core units , preferably j = 2-8 units, and are optionally denvated with 1-40, preferably 4-20 ethylene oxide units or propylene oxide units. The alkyl radicals in the alkyl glycosides for the purposes of the present invention (see above for definition) are preferably linear and branched, saturated, mono- or polyunsaturated carboxylic acids, particularly preferred natural fatty acids. Particularly preferred compounds from (C-2) are sorbitan fatty acid esters, very particularly sorbitan monooleate, sorbitan trioleate, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan tristearate, sorbitan monomyristate, sorbitan monococoate (sorbitan esterified with a mixture of fatty acids) from a mixture of fatty acids.

Co-surfactants (C-3) for the purposes of the present invention are linear and branched, saturated, mono- or polyunsaturated aliphatic alcohols, multiple alcohols (especially diols), fatty alcohols and oxo alcohols with a C chain length of i = 4-30, preferably i = 4 -25, particularly preferably i = 8-20. Co-surfactants consisting of technical-quality fatty alcohols are very particularly preferred.

Efficiency boosters (C-4) are amphiphilic block copolymers consisting of at least one hydrophobic and at least one hydrophilic block, preferably block copolymers of the form A-B, particularly preferably A-B block copolymers, in which A is polyethylene and B is polyethylene oxide.

Ionic surfactants (D) according to embodiment (1) include alkylethanolamines and their salts, alkyldiethanolamines and their salts, alkylamines and their salts, carboxylic acids and their salts, alkylsulfates and alkylsulfosuccinates. The alkyl radicals according to the invention (def. S. above) are preferably linear and branched, saturated, mono- or polyunsaturated aliphatic compounds, in particular alkyl chains, aliphatic alcohols, fatty alcohols, oxo alcohols and carboxylic acids, whose C chain length i = 3-30, preferably i = 4-24, particularly preferably i = 12-20. The amino groups of the alkylamines, alkylethanolamines and alkyldiethanolamines can be substituted once, twice or three times (three times only with alkylamines, not with alkylethanolamines) with the alkyl radicals according to the invention and optionally additionally with short-chain alkyl radicals, preferably methyl, ethyl, propyl and butyl. It is also possible to use quaternary ammonium salts which are alkyl-tri (short-chain alkyl radical) ammonium salts or dialkyl-di (short-chain alkyl radical) ammonium salts and whose counterions are inorganic or organic anions, preferably selected from OH, Cl, Br, HC0 ₃ , C0 ₃ , N0 ₂ , N0 ₃ , acetate, oxalate, propionate. Can also be used from the hitherto listed amines derived diamines, which are bridged together via a carbon chain of i = 2-10 C atoms, and their salts.

All amine and ammonium surfactants can also be ethoxylated with j = 1 to 30 ethylene oxide units (bivalent surfactants).

Another class of compounds within the ionic surfactants (D) are the salts of fatty acids, the fatty acids having chain lengths of i = 3-30, preferably i = 8-26, particularly preferably i = 12-20. Ammonium ions or alkali metal ions are used as cations, preferably ammonium ions or Li ⁺ , Na ⁺ , K ⁺ , very particularly preferably ammonium ions. Preferred fatty acid anions are oleate, stearate, palmitate, myristate, laurate and cocoate. Free carboxylic acids with a chain length of i = 4-30, preferably i = 8-26, particularly preferably i = 12-20 can also be used as component (D), the carboxylic acid being linear or aromatic, branched or unbranched, saturated, simple or can be polyunsaturated. Carboxylic acids of natural origin, ie natural fatty acids (such as oleic acid), citric acid, salicylic acid etc. are preferred. Salts of carboxylic acids can also be used, ammonium ions, tetra (short-chain alkyl radical) ammonium ions, quaternary hydroxylamines or alkali metal cations being used. For use as a fuel, it is particularly preferred that the ionic surfactants (D) are sulfur-free. Sodium alkyl sulfates or sodium bisalkyl sulfosuccinates with an alkyl radical as defined above and chain lengths of i = 6-20 can be used as the only sulfur-containing members of the ionic surfactants (D) and particularly preferably bis (2-ethylhexyl) sulfosuccinate (AOT).

Preferred ionic surfactants (D) are alkylamines and carboxylic acids and their salts, very particularly preferably fatty acids and alkylamines with 12-20 C atoms.

The group of salts and additives (E) comprises one or more compounds selected from non-halide salts (E1), halides (E-2) and additives (E-3). The proportion of additives (E) in the total microemulsion is 0-4% by weight, based on the total microemulsion, preferably 0.01-2.5% by weight, particularly preferably 0.05-1.5% by weight .-%, very particularly preferably 0.05-1.2 wt .-%. The group of non-halide salts (E1) includes carbonates, bicarbonates, acetates, benzoates, oxalates, propionates, citrates, formates, nitrates and nitrites and other water-soluble non-halides. Alkaline and alkaline earth metal ions and ammonium ions, preferably Li ⁺ , Na ⁺ , K ⁺ , Ca ²⁺ and NH ₄ ^+, serve as cations in salts of group (E1). Preferred compounds from group (E1) are the ammonium salts. The proportion of the compounds from group (E1) in the aqueous component A is 0-50% by weight, preferably 0-20% by weight, particularly preferably 0.01-10% by weight, very particularly preferably 0.01 - 6% by weight.

The group of halides (E-2) includes all water-soluble halides, preferably chlorides, bromides and iodides of the alkali metals and ammonium ion. In the case of ammonium halides, in particular NH ₄ CI, the proportion of the aqueous component (A) is 0-50% by weight, preferably 0

- 20% by weight, particularly preferably 0-10% by weight, very particularly preferably 0.1

- 5% by weight. In the case of all other halides, this proportion is 0-10% by weight, preferably 0.1-8% by weight, particularly preferably 0.1-4% by weight.

The additives (E-3) include urea and its derivatives as well as other water-soluble, nonionic additives. They can be used in proportions of 0-25% by weight of component (A), preferably 0.5-15% by weight, particularly preferably 0.5-10% by weight. Component (E) is also preferably sulfur-free.

The mixing ratios in the microemulsion according to embodiment (1) are calculated as follows, with groups (A), (B), (C), (D) and (E) - provided they are contained in the mixtures - always one or several components can be included:

The components from (E) are added proportionally to (A) in the calculations.

The ratio of (A (+ E)) to (B) is α = B / (A (+ E) + B) where = 0.04-0.99, preferably α = 0.45-0.99, particularly preferred =

0.45-0.90, very particularly preferably α = 0.60-0.90. The ratio of the amphiphilic component (sum of C and D) to

Total mixture is calculated from γ = (C + D) / (A (+ E) + B + C + D) with γ = 0.005-0.20, preferably γ = 0.005-0.15, particularly preferably γ = 0.01 -

0.08, very particularly preferably γ = 0.01-0.05.

in those cases in which an ionic surfactant of group (D) in the

Mixture is included (the proportion of D is therefore not zero), the following applies: δ = D / (C + D) with δ = 0.05-0.95, preferably δ = 0.10-0.50, particularly preferably δ = 0.20-0.40, very particularly preferably δ = 0.25-0.35.

Especially for those mixtures in which compounds from group (C-2) are contained in the amphiphilic component, the ratio of

(C-2) ZU Ccesamb δ = (C-2) / C total with δ = 0.00-0.85, preferably δ = 0.10-0.60, particularly preferably δ = 0.20-0.55, very particularly preferably δ = 0.35-0.55.

Preferred especially for those mixtures in which as amphiphilic

Component contains only compounds from groups (Cl) and (C-2), applies to the ratio of (C-2) to (Cl): δ = (C-2) / (Cl) + (C-2) with δ = 0.00-0.80, preferably δ = 0.10-0.60, particularly preferably δ = 0.15-0.50.

Preferred especially for those mixtures in which as amphiphilic

Component only contains compounds from groups (C-2) and (C-3), applies to the ratio of (C-3) to (C-2): δ = (C-3) / (C-2) + (C-3) with δ = 0.00-0.40, preferably δ = 0.00-0.20, particularly preferably δ = 0.05-0.20.

Especially for those mixtures in which compounds from group (C-4) are contained in the amphiphilic component, the ratio of

(C-4) TO C _Ge s_π.t: δ = (C-4) / C _total with δ = 0.00-0.20, preferably δ = 0.00-0.10, particularly preferably δ = 0.01-0.10.

For those mixtures in which compounds from group (E) are contained, the following applies to the ratio of (E) to (A + E): ε = (E) / (A + E) with ε = 0.00-0 , 50, preferably ε = 0.00-0.20, particularly preferably ε = 0-0.10.

The formulation and optimization of fuel microemulsions according to embodiment (5) comprises the following steps:

1 Preparation of a microemulsion from water (A), conventional fuel (B) and nonionic surfactant (C), preferably E- ,, at φ = 0.5 with pure surfactants or suitable technical surfactant mixtures. 2. Replacement of the pure surfactants with suitable technical surfactant mixtures. 3. Addition of additives (E) and optimization of efficiency through Efficiency Booster (C-4). 4. Setting the temperature invariance of the single-phase microemulsion by mixing technical ionic (D) and nonionic (C) surfactants. 5. Adjust the salinity (E). 6. Setting the water-OI ratio in the range φ = 0.04-0.99, preferably φ = 0.04-0.96. 7. Determination of the optimal Wasser-OI-Verhaltnιsses by combustion, then reiteration of the optimization, in particular by adding further additives.

The order of the formulation steps can be changed, in particular the additives (E) to (A) can be added in the first step (see Example 1), and optionally iteratively

The bicontuit and the sponge structure of the microemulsions according to (1) can be demonstrated by the high electrical conductivity of the oil-rich microemulsions, by electron microscopy, neutron scattering experiments and by NMR self-diffusion measurements. The microscopic structure of a continuous microemulsion according to the invention consisting of equal amounts of water and n-octane with a surfactant content (C ₂ E ₅ ) of 5% is shown in FIG Figure illustrates the three-dimensional contiguous shape of the surfactant film, which separates water and oil on a microscopic level.

Optimal microemulsions are characterized in that when water or oil is added, they are eliminated as an excess phase. Optimal microemulsions are thus swollen to the maximum with water and oil, and their surfactant content cannot be further reduced. The microemulsions according to the invention include water, hydrocarbon mixtures,

Emulsifier mixtures and optional cosurfactants, additives as well as additives such as anti-corrosives or preservatives.

The emulsifier mixtures (C / D) made of non-ionic and ionic surfactants are optionally based on renewable raw materials. They are adjusted for each oil so that temperature-invariant single-phase areas are between -30 ° C and + 95 ° C, preferably between -30 ° C and + 70 ° C.

A certain salt content in the water is useful when using ionic surfactants. Flammable inorganic salts such as ammonium carbonates, ammonium acetates and ammonium nitrates are used here, which at the same time reduce pollutant emissions. The low temperature stability is achieved with glycerin, ethanol and / or other additives. The addition of short-chain alcohols (methanol, ethanol, propanol) in fuel microemulsions is advantageous, since the alcohol accumulates in the internal interface between the water and fuel domains due to its interfacial activity. On the one hand, this reduces the vapor pressure of the alcohol, and on the other hand the alcohol present in the interface itself does not cause an increase in the vapor pressure of volatile components such as benzene and other aromatics.

The mixtures obtained in this way are optimized with respect to the emulsifier content to such an extent that water and conventional fuels with an emulsifier content of less than 5% can be mixed in a thermodynamically stable manner. The surfactants are characterized by the fact that they are completely combustible and residue-free. According to the invention, continuous water and oil areas in the microemulsions are separated by an amphiphilic film consisting of the emulsifier mixture. A characteristic of these bicontinuously structured microemulsion fuels is their good electrical conductivity. The measurement of the latter is therefore a simple method for detecting bicontinuity. The electrical conductivity opens up new ignition and dispersion options by applying high voltages and the resulting high current density.

The optimal microemulsions according to the invention are notable for their special emulsifier mixtures (see above) and the solubilization efficiency achieved thereby. Conventional fuels and water with an emulsifier content of significantly less than 5% can be mixed in a thermodynamically stable manner.

This high efficiency leads to the formation of a uniform micro structure of water and fuel domains on the microscopic level in the order of 100 nm, which allows the setting of optimal combustion conditions. The new microemulsion fuels, such as emulsions, appear optically cloudy due to the strong light scattering. Nevertheless, they are single-phase, thermodynamically stable microemulsions.

Particularly noteworthy is the property that the bicontinuous microstructuring of the microemulsion fuels according to the invention correlates with the occurrence of very low interfacial tensions between water and conventional fuel in the order of 10 ^"4 mNm ^{" 1} . As a result, the microemulsion fuel is distributed significantly better than conventional fuel / water mixtures when it is injected into the combustion chamber, so that the hydrocarbons are burned more completely. This results in a significant increase in combustion efficiency and a reduction in pollutant emissions (above all from PM and HC, but also from CO).

A further minimization of emissions and improvement of the energy yield is achieved by transferring the water solubilized in the microemulsion from the caused liquid in the gaseous state, whereby the piston of an internal combustion engine is propelled in addition to the combustion gases ("steam engine effect").

At the same time, due to the enthalpy of vaporization to be achieved, reaction heat is dissipated and the temperature in the combustion chamber is thus reduced. This results in a significant reduction in pollutants in the exhaust gases (mainly NO _x and CO, but also HC and PM).

Seen overall, the overall efficiency of the internal combustion engine is not significantly reduced by the use of the microemulsion fuels according to the invention despite the reduction in the combustion temperature.

In order to eliminate or reduce pollutant emissions, both inorganic and organic additives can additionally be added to the optimal, bicontinuous microemulsions.

The microemulsion fuels according to (1) consist of at least one aqueous, one hydrophobic and one amphiphilic pseudo component. The aqueous component mainly consists of water. If necessary, additives such as small amounts of salt, glycerol and / or other water-soluble substances can be added to this. The use of TBA and short-chain alcohols (methanol and ethanol) can be dispensed with. The fuel / water quality (e.g. definable by the octane number), suppression of undesired structures (lamellar phase), winter resistance and favorable combustion properties can be adapted to the various requirements by adding ethanol and methanol. The microemulsions according to the invention offer considerable advantages over conventional products.

The microemulsions according to embodiment (1) have an oil to water plus oil volume ratio φ of φ = 0.04 to φ = 0.99, preferably to φ = 0.96, and have a bicontinuous microstructure. Their thermodynamic stability is ensured by a suitable emulsifier or a mixture of emulsifiers reached. Suitable, technical surfactant mixtures of non-ionic and ionic surfactants exist for each oil in order to obtain single-phase areas between - 30 ° C and + 95 ° C, preferably between -30 ° C and + 70 ° C, with these temperature-invariant areas. The formation of disruptive anisotropic and highly viscous structures is prevented.

For the use of ionic surfactants, a low salt content in the water is preferred, which is achieved by using combustible inorganic salts, preferably ammonium carbonates, ammonium nitrates, etc. At the same time, this leads to a reduction in pollutant emissions during combustion.

The viscosity of the microemulsion according to (1) preferably corresponds to the viscosity of the pure hydrocarbon of the oil component.

The mixtures obtained in this way according to (1) are optimized with regard to the emulsifier content. Longer chain aliphatic alcohols (e.g. 1-octanol) of group (C-3) and block copolymers (C-4) can be used as cosurfactants to increase efficiency. The cosurfactants used can also be burned completely without residues and do not cause any additional pollutant emissions during combustion.

The emulsifier mixtures according to the invention consist of inexpensive surfactants, which can usually be produced from renewable raw materials. Alternatively, a combination of sugar surfactants with a longer-chain alcohol is used.

Short-chain alcohols, preferably ethanol, methanol or propanol, can also be used as a constituent of the aqueous phase. The problem of high alcohol vapor pressure in conventional fuels does not arise in a microemulsion according to embodiment (1) when these alcohols are used, since the alcohol accumulates in the internal interface because of its interfacial activity and therefore does not significantly increase the fugacity. A comparison of the vapor pressure curves of water / ethanol mixtures with those of ethanol-containing microemulsions shows that the ethanol vapor pressure is significantly lower than bicontinuous microemulsions. For each fuel / water mixture according to the invention, there is a specific, optimal oil-water ratio, which firstly delivers the lowest pollutant emissions during combustion and secondly is the most efficient to burn. The microemulsions can be varied and optimized by means of further additives such as alcohols and organic and / or inorganic additives. According to the invention, the ratio of the aqueous to the hydrophobic component can be freely adjusted in almost any mixing ratio due to the special characteristics of the microemulsions.

The fuels of bicontinuous microemulsions according to the invention have the following advantages over conventional fuels:

The combustion temperature is reduced. The hydrocarbons are burned more completely. The use of the heat of combustion for the evaporation of the water allows an efficient use of the energy content of the hydrocarbons even at low combustion temperatures. Due to the reduced combustion temperature, the emissions of pollutants (CO, NO _x , HC, soot, PM) can be significantly reduced. The tendency to knock in gasoline engines can be reduced. This can reduce the use of anti-knock agents such as aromatics or MTBE. The use of biodiesel and / or bio oil is possible despite its water content.

Compared to the known fuel / water mixtures, the fuels according to the invention made from bicontinuous microemulsions have the following advantages:

The microemulsion fuels according to the invention are distinguished by their thermodynamic stability. They are based on optimal microemulsions with bicontinuous microstructuring, which are characterized by minimal amounts of surfactants are, have low oil-water interface tensions and monodisperse structure sizes and are electrically conductive. Raw materials can be saved by the more efficient combustion of bicontinuous microemulsions. The proportion of water or aqueous components is freely selectable. This allows the water content to be adjusted to optimal combustion conditions. - The optimal microemulsions require only small amounts of emulsifiers (<5%) and are therefore inexpensive. The combination of emulsifiers enables temperature-insensitive, single-phase microemulsions to be formulated (for example with a stability range from -30 ° C to + 70 ° C). - Short-chain alcohols can be used in microemulsions without fugacity problems, since continuous water domains are available. - Diesel, biodiesel, bio oil, petrol, super, kerosene and heating oil can be produced as bicontinuous microemulsion fuels. The combustion of the hydrocarbons is more complete than with conventional fuel / water mixtures (Example 10). The microemulsion fuels can be premixed and - due to their stability - stored in conventional tanks. Microemulsion fuels can be mixed easily just before combustion.

The invention is explained in more detail with reference to the following examples, which, however, do not restrict the subject of the invention and the method according to the invention.

Examples

Example 1: Preparation of bicontinuous microemulsions from components (A (+ E)). (B) and (C / D.

In the first step, any necessary components (E) (each compound individually in the case of several components (E)) were dissolved with stirring in demineralized water as the first component (A). All other aqueous components (A), such as e.g. short-chain alcohols, glycerin etc., mixed with the solution. If component (B) consisted of two or more components, these were first mixed together homogeneously. The nonionic surfactants (C) were then added with stirring. Solid surfactants had to be completely dissolved. If necessary, the mixture was homogenized by adding heat to about 60 ° C. with stirring. In the following - if necessary - the ionic surfactants (D) were added with stirring. Solid surfactants had to be completely dissolved again. The mixture had to be homogenized again. The aqueous component (A (+ E)) was added to the oil / surfactant mixture (B + C (/ D)). The thermodynamic equilibrium was spontaneously established while stirring at room temperature. By applying heat (up to 60 ° C), the single-phase microemulsion may have formed more quickly.

Example 2: Composition of single-phase bicontinuous microemulsions,

Lutensol®T05 is a C13 oxo alcohol + 5 ethylene oxide units. Lutensit®A-BO is the sodium salt of dioctylsulfosuccinate (AOT) in technical quality, dissolved in water (concentration approx. 60% AOT).

(optional + ethanol), diesel, Lutensol XL 80, sorbitan monooleate Lutensol XL® 80 is a decanol alkoxylate with approx. 8 ethylene oxide units and is based on a ClO-Guerbet alcohol. K-7 components: proportions of total mixture (based on% by weight) range preferred composition: Example 5: Composition of microemulsions consisting of water, diesel, Lutensol TQ5 _r AOT, NaCI (+ urea)

Diesel, Lutensol TQ5, AOT, ammonium acetate Lutensol ® T06 is a C13 oxo alcohol + 6 ethylene oxide units. Preferred composition area

A water (fully desalinated) 4 to 12.5 8.51 B diesel 68 to 86 78.4 Lutensol ^® TQ5 [Cι _{2 /} ι ₄ E ₅ 1 6.7 to 12.0 8.6 D Lutensit ^® A-BO [ AOT] * 3.3 to 6.0 * 4.3 * (NH ₃ ) acetate 0.09 to 0.40 0.19 Stable at RT / temperature invariant (> 0 ° C to 95 ° C) *) Lutensit ^® A -BO [AOT + 40% water] = parts by weight based on active substance (AOT), water added to A.

Example 7: Composition of microemulsions consisting of water, diesel, Lutensol T06, ammonium oleate. ammonium acetate

Example 8: Composition of microemulsions consisting of water, diesel, Lutensol T05 and T03 Lutensol ® T03 is a C13 oxo alcohol + 3 ethylene oxide units

Example 9: Measurements on engine test benches A) Test bench I: The first combustion measurements were carried out on an engine test bench at the University of Duisburg. It was a Hatzmotor (diesel) used. The measurement was carried out at a constant speed of 1500 min ^"1. The load and thus the power were set by means of a brake. Two loads, 14.0 Nm (2.20 kWh) and 9.6 Nm (1, 51 kWh) In addition to the microemulsion, a reference fuel (diesel) was burned for direct comparison. The consumption was determined using a fuel balance. In addition to the exhaust gas temperature, the pollutants NO _x , CO, HC and soot as well as 0 ₂ and C0 in the exhaust gas were measured. For carbon black, the Bosch number and the particle size distribution were determined using a differential mobility analyzer.

B) Test bench II: Further combustion experiments were carried out on an engine test bench from ISP in Salzbergen. Here a VW TDI engine (turbodiesel) was used. A standard diesel was used as the reference fuel. The fuel consumption was determined based on the MVEG cycle (EU directive 93/116 / EC) using a fuel balance. In addition, analogous to test bench I, a partial load stage (N = 2500 min ^"1 / Md = 75 Nm) and two full load stages (N = 1900 min ^{" 1} and N = 4000 min ^"1 ) were started to determine exhaust gas temperatures and the pollutants soot (smoke values). and NO _x as well as to measure the maximum power at the full load levels. The fuel consumption was also determined at the partial load level.

In these measurements, the water content was varied from 0 to 8.7% and from 9 to 27%. The following component mixtures (derived from K-12 and K-10) were used: (A) was water in all mixtures, (B) was diesel in all mixtures used, (C) in all mixtures used Lutensol T05, (E) in all mixtures of ammonium carbonate. (D) was either pure AOT or Lutensit ® A-BO, in the latter case the water content of Lutensit® A-BO was calculated out to calculate the AOT content and water content and added to (A).

Example 10: Results of the measurements on engine test benches A) Test bench I: The measurement results are shown in FIG. 3. The first combustion measurements already showed significant improvements in the microemulsion compared to the reference diesel, although it was not yet the most suitable microemulsion. The exhaust gas temperature decreased by 50 K for the smaller and 100 K for the larger load compared to the reference diesel. The fuel consumption and the efficiency, based on the combustible components (without water) were almost the same. As part of the measurement error, the microemulsion even showed a slightly better efficiency. The microemulsion reduced exhaust emissions compared to the reference diesel. For example, NO _{x was} reduced by up to 26% and CO by up to 32%. The Bosch number (soot particles) was reduced by up to 37%, whereby the measurable particles became smaller and their number increased.

B) Test bench II: The measurement results are shown in FIG. 4. The first combustion experiments with variation of the water content showed improvements compared to the reference one when using microemulsions. It was observed that the exhaust gas temperature decreased linearly with the water content. The fuel consumption and the efficiency, based on the combustible components, remained the same here as in Example 10A. Here too, as in Example 10A, slight reductions in fuel consumption could be seen within the measurement error. Measurements at higher water contents even indicated an increase in efficiency. No change in NO _x emissions compared to the reference diesel was observed for small water fractions. In contrast, the NO _x emission was reduced by approx. 10% at higher water proportions. The measurable soot was drastically reduced, even to a small extent, in some cases to below the measurement limit. For example, around 85% less soot was measured even at low water concentrations.

Claims

1Patentansprüche

1. Bicontinuous single-phase microemulsion consisting of at least one aqueous component (A), a hydrophobic component (B) and an amphiphilic component (C / D), the microemulsion having a continuous aqueous phase and a continuous hydrophobic phase and the hydrophobic component (B) contains one or more substances which can be used as motor fuels.

2. Microemulsion according to claim 1, wherein the aqueous component (A) (i) is selected from water and alcohol-water mixtures and / or (ii) 10 to 100 wt .-%, preferably 70 to 100 wt .-%, particularly preferably Contains 80-100% by weight of water and / or (iii) additional salts and additives (E) selected from the group comprising alkali halides, ammonium halides, ammonium salts of organic acids and urea derivatives, preferably ammonium salts of organic acids, very particularly preferably ammonium carbonate and ammonium acetate, contains, the additives (E) in concentrations of 0-4 wt .-% based on the total microemulsion, preferably from 0.01-2.5 wt .-%, particularly preferably from 0.05-1.5 wt .-%, very particularly preferably from 0.05-1.2 wt .-%.

3. Microemulsion according to claim 1 or 2, wherein the hydrophobic component (B)

(i) contains at least one fuel based on mineral oil, preferably selected from the group of petrol (gasoline and super), diesel fuel, heavy oil, kerosene, petroleum and heating oil, and / or

(ii) contains at least one fuel, heating or fuel based on vegetable oils or their derivatives, in particular selected from biodiesel, rapeseed oil methyl ester (RME) and bio oil.

4. Microemulsion according to claim 3, wherein the hydrophobic component (B) as a component contains diesel fuel, preferred

(i) pure diesel or 2

(ii) a mixture of on the one hand diesel, gasoline or super gasoline with on the other hand bio oil and / or biodiesel in any mixing ratio, very particularly preferably pure diesel or a mixture of diesel and biodiesel and / or bio oil.

5. Microemulsion according to one or more of claims 1 to 4, (i) which is electrically conductive and / or thermodynamically stable and / or temperature stable, and / or (ii) wherein the proportion of the amphiphilic component (C / D) 0.5 is up to 20% by weight, preferably 0.5 to 15% by weight, particularly preferably 1-8% by weight, very particularly preferably 1-5% by weight and / or (iii) the proportion of the aqueous component (A) is 0.5 to 65% by weight, preferably 5 to 55% by weight, particularly preferably 15 to 45% by weight and / or (iv) the proportion of the hydrophobic component (B) being 4 to 99 % By weight, preferably 45 to 99% by weight, particularly preferably 45-90% by weight, very particularly preferably 60 to 90% by weight.

6. The microemulsion according to one or more of claims 1 to 5, wherein the amphiphilic component (C / D) contains at least one nonionic surfactant (C), the nonionic surfactant preferably being selected from

(i) linear or branched surfactants (Cl), in particular polyethylene oxide and polypropylene oxide derivatives of organic alcohols, organic phosphoric acid esters, alkylphenol ethoxylates, mono- or polyalkylated polyethylene glycols (PEG) and polypropylene glycols (PPG), preferably polyethylene oxide derivatives of organic alcohols, particularly preferably with C chain lengths of 10-20 C atoms and 4-10 ethylene oxide units, and / or (ii) surfactants with a core structure (C-2), in particular sugar surfactants, preferably selected from the group comprising the alkyl glucosides (QGj), ( Poly) alkyl sorbitans (Sj), alkyl maltosides (Mj), alkyl lactosides and their ethoxylated and propoxylated derivatives, very particularly preferably alkyl sorbitans.

7. The microemulsion according to claim 6, wherein the amphiphilic component (C / D) additionally at least 3

(i) an ionic surfactant (D), in particular a sulfur-free ionic surfactant (D), preferably selected from the group comprising alkylethanolamines,

Alkyldiethanolamines, alkylamines, carboxylic acids, alkyl sulfates and

Alkyl sulfosuccinates and their respective salts, particularly preferably alkylamines and carboxylic acids and their salts, very particularly preferably fatty acids and

Alkylamines with 12-20 C atoms, and / or

(ii) a cosurfactant (C-3), in particular selected from aliphatic alcohols, preferably fatty alcohols, and / or

(iii) an efficiency booster (C-4) selected from amphiphilic block

Contains copolymers.

8. Microemulsion according to claim 6 or 7, wherein the amphiphilic component (C / D) in addition to a linear or branched surfactant (C-1) at least

(i) an ionic surfactant (D) and / or

(ii) a sugar surfactant (C-2) and / or

(iii) contains an alcohol, preferably a medium or long chain alcohol; and

(iv) the proportion of component (C) comprising components from the groups

(C-1), (C-2), (C-3) and (C-4) on the amphiphilic component (C / D) 50-100

% By weight, preferably 60 to 80% by weight, very particularly preferably 65-75% by weight; and or

(iv) the proportion of component (C-2) in the total amount of component (C)

0-85% by weight, preferably 10 to 60% by weight, particularly preferably 20 to 55

% By weight, very particularly preferably 35 to 55% by weight.

9. The microemulsion according to one or more of claims 1 to 8, wherein component (A) is water or a water-ethanol mixture, component (B) is diesel, component (C) comprises at least one polyethoxylated long-chain alcohol, and the proportion of (C) in the microemulsion being 1 to 10% by weight.

10. Microemulsion according to claim 9, wherein (A) water, (C) is a polyethoxylated Cι ₃ oxo alcohol (C _{i2 / 14} E ₅ ), (E) ammonium carbonate and is preferred 4

(i) is (D) AOT and particularly preferably the following proportions of the components are present: (A) 1 to 50% by weight, (B) 30 to 93% by weight, (C) 3-18% by weight, (D) 1 to 8% by weight and (E) 0.06-1.3% by weight, and / or (ii) (D) is a mixture of oleic acid and dodecylamine, and the following proportions of the components are particularly preferably present : (A) 5-25% by weight, (B) 79-91% by weight, (C) 2.2-7.2% by weight, (D) 0.45-1.2% by weight. % Oleic acid, 0.3-1% by weight dodecylamine, (E) 0.15-1.2% by weight,

11. The microemulsion according to claim 9, wherein (C) is a polyethoxylated decanol (Cι ₀ E ₈ ) in combination with sorbitan monooleate and preferably (i) the following proportions of the components are present: (A) 39-55% by weight, (B) 34-47 wt .-%, (C) Cι ₀ E ₈ 4.2-10.5 wt .-% and sorbitan monooleate 2.8-9 wt .-%, and / or (ii) (A) contains ethanol, and the ethanol fraction in the microemulsion is particularly preferably 2.0-7.4% by weight.

12. A microemulsion according to claim 9, wherein (A) water, (C) a polyethoxylated Cι ₃ oxo alcohol (Cι _{2 /} ι ₄ E _5), (D) AOT and is preferably (i) (E) sodium chloride, and particularly preferred are the following Components of the components are present: (A) 4 to 55% by weight, (B) 37 to 86% by weight, (C) 3.5-12% by weight, (D) 3.3 to 8.2 % By weight and (E) 0.08-0.3% by weight, and / or (ii) (E) is sodium chloride and urea and the following proportions of the components are particularly preferably present: (A) 6-10% by weight. -%, (B) 75-85% by weight, (C) 8-12% by weight, (D) 4-6% by weight, (E) 0.15-0.25% by weight NaCl, 0.12-0.20% by weight urea, and / or (iii) (E) ammonium acetate and the following proportions of the components are particularly preferably present: (A) 4-12.5% by weight, (B ) 68-86% by weight, (C) 6.7-12.0% by weight, (D) 3.3-6.0% by weight, (E) 0.09-0.4% by weight .-%.

13. Microemulsion according to claim 9, wherein (A) water, (C) is a polyethoxylated Cι ₃ oxo alcohol (Cι ₂ ι ₄ E ₆ ), (D) ammonium oleate and (E) ammonium acetate and 5

the following proportions of the components are preferably present: (A) 40 to 60% by weight, (B) 40 to 60% by weight, (C) 1.5-2.5% by weight, (D) 1.5 to 2.5% by weight and (E) 0.6-1.6% by weight.

14. Microemulsion according to claim 9, wherein (A) water, (C) is a polyethoxylated C ₁₃ oxo alcohol (Cι ₂ ι ₄ E ₅ ) and another polyethoxylated alcohol, preferably a polyethoxylated C _i3 oxo alcohol (Cι ₂ ι ₄ E ₃ ) , and preferably the following proportions of the components are present: (A) 40 to 52% by weight, (B) 40 to 52% by weight, (C) 3.0-8.0% by weight per individual component.

15. A microemulsion according to one or more of claims 1 to 14, which is a fuel.

16. Use of the microemulsion as defined in claims 1 to 14,