EP0166006A1 - Motor fuel - Google Patents

Abstract

Motor fuels based on lower alcohols according to Patent Application 33.08433.5 contain additions of mixtures of C5/C6- and C5-C7- hydrocarbons as well as petrol and mixtures of C4-hydrocarbons.

Description

The invention relates to fuels based on lower alcohols which contain additions of mixtures of saturated C ₅ / C ₆ -, C ₅ - C ₇ hydrocarbons as well as gasoline and mixtures of saturated C ₄ hydrocarbons.

Distilled methanol, so-called pure methanol, has been intensively investigated as an alternative fuel for several years. (Chemical technology, Winnacker-Küchler, Vol. 5, Organic Technology I, 4th edition, 1981, p. 517.) Also additives such as higher alcohols and water to methanol for use as fuel are known. (N. Iwai, The combustion of methanol mixed with water, Second Nato-Symposium; Nov. 4-8, 1974, Düsseldorf.)

An older patent US Pat. No. 23,65,009 describes combinations of alcohols with 1-5 C atoms with saturated and unsaturated hydrocarbons with 3-5 C atoms. Furthermore, 2,404,094 (Conti nation U.S. Patent No. 2,365,009 in Part) is described a fuel by the same applicant in US-PS, either of absolutely pure methanol or commercially available distilled anhydrous methanol is (column 6, lines 8-11) and aliphatic C ₃ -C ₅ contains hydrocarbons. This application also claims a methanol fuel containing 2-20% of a C ₄ or C _S aliphatic hydrocarbon. According to column 5, lines 22-27, hydrocarbons in highly pure form are preferred. Furthermore, the hydrocarbons used can also be partially unsaturated or consist of unsaturated hydrocarbons (column 5, lines 28-34). In the examples (Table 1) the additional components specified are n-petane, isopentane and a C _{4 cut} which contains up to 20% butenes. According to claims 5 and 6, a mixture of saturated C ₅ hydrocarbons can also be used for the spe case of fuel for aircraft engines. US Pat. No. 2,365,009 also describes mixtures of ethanol with aliphatic C ₃ -C _S hydrocarbons, where the aliphatic hydrocarbons can be both saturated and unsaturated, and preferably isopentane (Claim 8 and Table 1) is admixed as the hydrocarbon.

Further examples of ethanol / hydrocarbon mixtures are described in DE-OS 2,806,673 and DE-OS 3,211,775. In particular, experts are aware of the efforts in countries where ethanol is abundant, such as. B. in Brazil to use this both pure and in a mixture with hydrocarbons (petrol) as fuel (e.g. Chemical Engineering Process, April 1979, p. 11).

On the other hand, the experts are aware of important fuel-specific disadvantages of the lower alcohols. B. the poor cold start behavior, the poor driving behavior at low outside temperatures, unsatisfactory miscibility with hydrocarbons, especially at low temperatures, and the wide explosion range when mixed with hydrocarbons. The cold start problems are to be found in the low ignitability of the alcohols methanol and ethanol. A measure of the ignitability is the vapor pressure of a fuel, which is measured at 37.7 ° C according to the so-called Reid test.

For comparison, gasoline in the Reid test has a vapor pressure of 700 mbar, while methanol has a pressure of 350 mbar. At outside temperatures below 15 ° C, the vapor pressures of methanol and ethanol are so low that a gaseous, ignitable mixture is no longer possible is. The explosion limits of pure methanol in air are 6.75 to 36.7 vol.%, So that there is an explosive fuel-air mixture in the vehicle tanks between + 15 ° C and +25 ° C. Additions of 6-9% by weight isopentane reduce the upper explosion limits to -7 ° C in summer and -20 ° C in winter. so that the security problems are largely eliminated.

Isopentane is also characterized by excellent solubility in both methanol and ethanol, especially at low temperatures. The best setting data for the vapor pressure of pure methanol turned out to be the upper vapor pressure values of the fuel standard DIN 51 600 with 700 mbar for summer and 900 mbar for winter fuel (Reid test).

In view of the problems described and the state of the art as well as the more recent investigations, isopentane (2-methylbutane) was therefore regarded as the optimal admixing component to date.

The fuel from distilled methanol and isopentane, known as M 100 fuel, has been tested in several auto fleet tests and has been used in municipal auto fleet tests for years, especially in the Federal Republic of Germany (see H. Müller; 27th DGMK main conference, 6. -Oct. 8, 1982). Although methanol containing isopentane to some extent meets expectations for a usable motor fuel, the studies unexpectedly have shown that there are still significant disadvantages to this fuel. In summer operation in particular, the vapor pressure is too high when using pure methanol, despite the reduction of the isopentane content to 5 to 6% by weight, with undesirable outgassing of the isopentane occurring as a result, while in winter operation despite an isopentane content of up to 9% by weight, a vapor pressure drop occurs at low temperatures, which means that the cold start properties leave something to be desired in winterly cold temperatures below -10 ° C.

The object of the present invention was therefore to find fuels based on methanol and ethanol which provide better cold start behavior, better driving behavior, in particular at relatively high and relatively low outside temperatures, as is required in practical motor vehicle operation, with perfect solubility even in winter operation and Ensure lower outgassing in summer operation and at the same time ensure safe operation without an explosive mixture occurring in the fuel tank.

• a) die Gesamtmenge an C₄-, C₅/C₆-, bzw. C₅-C₇-Kohlenwasserstoffen bzw. Benzin im Kraftstoff 0,1-15 Gew.% bzw. 0,1-18 Gew.% bzw. 0,1-25 Gew.% beträgt und
• b) das Verhältnis von C_{4 :} C₅/C₅ bzw. C₅-C₇-Kohlenwasserstoffen bzw. Benzin, 1 : 500 Gewichtsteile bis 3 : 1 Gewichtsteile beträgt, sowie durch

This object was achieved according to the invention by means of fuels based on methanol with, if appropriate, up to 15% by weight of water in the fuel, characterized in that the methanol has a mixture of C ₄ hydrocarbons and a mixture of C ₅ / C ₆ or C _S -C ₇ -Hydrocarbons or petrol is added,

• a) the total amount of C ₄ -, C ₅ / C ₆ - or C ₅ -C ₇ hydrocarbons or gasoline in the fuel 0.1-15% by weight or 0.1-18% by weight or Is 0.1-25% by weight and
• b) the ratio of C _4: C ₅ / C ₅ or C ₅ -C ₇ hydrocarbons or gasoline, 1: 500 parts by weight to 3: 1 parts by weight, and by

• a) die Gesamtmenge an C₄-, C₅/C₆- bzw. C₅ -C₇-Kohlenwasserstoffen bzw. Benzin im Kraftstoff 0,1-15 Gew.% bzw. 0,1-18 Gew.% bzw. 0,1-25 Gew.% beträgt und
• b) das Verhältnis von C_{4 :} CS/C6 bzw. C₅-C₇-Kohlenwasserstoffen bzw. Benzin, 1 : 500 Gewichtsteile bis 3 : 1 Gewichsteile beträgt,

bzw. durch Gemische der erfindungsgemäßen Kraftstoffe auf Methanol- und Ethanolbasis sowie durch Gemisch der erfindungsgemäßen Kraftstoffe mit Kraftstoffen auf Methanol- und Ethanolbasis, die Zusätze an C₄- und C_S-Kohlenwasserstoffen enthalten.Fuels based on ethanol, optionally with up to 25% by weight of water in the fuel, characterized in that a mixture of C ₄ hydrocarbons and a mixture of C ₅ / C ₆ or C ₅ -C ₇ hydrocarbons or gasoline are added to the ethanol becomes,

• a) the total amount of C ₄ -, C ₅ / C ₆ - or C ₅ -C ₇ hydrocarbons or gasoline in the fuel 0.1-15% by weight or 0.1-18% by weight or 0 , 1-25% by weight and
• b) the ratio of C _4: CS / C6 or C ₅ -C ₇ hydrocarbons or gasoline is 1: 500 parts by weight to 3: 1 parts by weight,

or by mixtures of the fuels according to the invention based on methanol and ethanol and by mixing the fuels according to the invention with fuels based on methanol and ethanol which contain additions of C ₄ - and C _S -hydrocarbons.

It has surprisingly been found for the person skilled in the art that mixtures of C ₄ hydrocarbons on the one hand and CS / C6 hydrocarbons, C ₅ -C ₇ hydrocarbons or gasoline on the other hand with pure methanol and with undistilled technical methanol, so-called raw methanol as well as with ethanol or technical water-based ethanol in an excellent, previously unrivaled way, deliver fuels that provide perfect cold start behavior and better driving behavior, especially at relatively high and relatively low outside temperatures, as is required in practical motor vehicle operation, with perfect solubility even in winter operation and low outgassing in summer operation and at the same time ensure safe operation without an explosive mixture entering the fuel tank. It was particularly surprising that the combination of the desired properties, i.e. sufficiently low outgassing at high outside temperatures, perfect cold start behavior at low outside temperatures and safe explosion limits was achieved despite the addition of a relatively low-boiling C ₄ component, even with a relatively high water content, therefore also in a very humid climate, there is no phase separation in the fuel mixture. In particular, it was surprising that there were technical cuts on C ₄ hydrocarbons on the one hand and C ₅ / C ₆ or C ₅ -C ₇ hydrocarbons or gasoline, as used in the refinery and primary chemicals production area, e.g. B. ethylene and gasoline / toluene (BT) plants, on the other hand, are excellent, despite different compositions of individual hydrocarbons.

The total amount of C ₄ hydrocarbons on the one hand and C ₅ / C ₆ or C ₅ -C ₇ hydrocarbons or gasoline on the other hand can be 0.1 to 25% by weight. The ratio of C ₄ hydrocarbons on the one hand to C ₅ / C ₆ or CS-C7 hydrocarbons and gasoline on the other hand can be 1: 500 to 3: 1. A ratio of C ₄ hydrocarbons on the one hand and C _S / C ₆ or C ₅ -C ₇ hydrocarbons or gasoline on the other hand is preferably from 1: 1 to 1:20.

Small amounts of non-C ₄ -C ₇ hydrocarbons, as are inevitable in technical fractions, can be contained in the fuel, regardless of whether they are non-aromatic saturated and / or unsaturated or aromatic hydrocarbons.

Suitable fractions of C ₄ , C ₅ , C ₆ and C ₇ mixtures are given by way of example in the following analyzes:

Usual normal and super fuels can be used as gasoline.

It is possible with the fuel according to the invention, as with numerous known alternative fuels, to admix certain amounts of other customary components, for example C ₃ - _' C ₄ - and higher alcohols, ethers, such as, for B. methyl tert-butyl ether and other available ethers, ketones such as acetone and additional aromatics such as benzene, toluene and xylenes can also be added.

The methanol quality previously used for methanol-based fuels is methanol processed by distillation, so-called pure methanol (absolutely pure or refined methanol). It is known to the person skilled in the art that high demands are made with regard to the purity of this methanol quality, a correspondingly high level of operational effort being required, particularly in the distillation area. Since certain technical problems occur, particularly with methanol fuel, such as corrosive and the dissolving action of methanol on motor vehicle parts such as lines, tank linings, engine parts and engine materials and, moreover, high demands are placed on complete combustion with regard to environmental pollution, and furthermore deposits, especially in the carburetor and engine, have to be avoided, there has been no distillative workup Methanol, as it occurs in low, medium or high-pressure synthesis plants (so-called raw methanol (non refined methanol)) was not considered suitable.

As is well known, raw methanol contains up to approx. 5% by weight of water numerous impurities, e.g. Formaldehyde, methyl formate, formic acid, dimethyl sulfide, formaldehyde dimethyl acetal, iron pentacarbonyl and other carboxylic acids and their esters.

It was an unpredictable result of the investigations of the applicant that, contrary to the prejudice according to the prior art, undistilled methanol is also outstandingly suitable for the fuels according to the invention, in particular with regard to the vehicle parts which come into contact with the fuel and with regard to on emissions. It has surprisingly been found that the emissions of CO, NO and hydrocarbons are lower than those when using pure methanol. The following table shows this:

According to the invention, a crude methanol can also be used which is not distilled, but is topped off with removal of non-volatile impurities.

• In Fig. 1 ist die Abhängigkeit des Dampfdrucks (absolut) eines erfindungsgemäßen Kraftstoffs mit C₄-/C₅-/C₆-Kohlenwasserstoff-zusatz von der Temperatur für Sommer- und Winterqualität für Reinmethanol und Rohmethanol dargestellt.
• In Fig. 2 ist die gleiche Abhängigkeit dargestellt, wobei C₄, C₅-C₇-Kohlenwasserstoffe zugesetzt wird.
• In Fig. 3 ist die gleiche Abhängigkeit dargestellt, wobei C₄-Kohlenwasserstoffe und Otto-Kraftstoff zugesetzt sind (OK).
• In Fig. 4 ist die gleiche Abhängigkeit dargestellt mit Ethanol/ Wasser (95,6 Gew.% Ethanol und 4,4 Gew.% H₂0) und C₄-/^C ₅/^C ₆-Kohlenwasserstoffen als Zusatz.
• In Fig. 5 ist die gleiche Abhängigkeit wie in Fig. 4, jedoch mit C₄- und C₅-C₇-Kohlenwasserstoffen als Zusatz dargestellt.
• In Fig. 6 ist die gleiche Abhängigkeit wie in den Figuren 4 und 5, jedoch mit C₄-Kohlenwasserstoffen und OK als Zusatz dargestellt.
• In Fiq. 7 ist in allqemeiner Form die Abhänaiakeit des Dampfdrucks von der Kohlenwasserstoffkonzentration dargestellt.
• Fig. 8 entspricht der Kurve der Fig. 7 für den beispielhaften Fall des Zusatzes von C₅/C₆-Kohlenwasserstoffen zu Ethanol (95,6%ig).
• Fig. 9 und Fig. 10 geben Vergleichsdampfdruckkurven mit Isopentanzusatz zu Rein- und Rohmethanol wieder, entsprechend dem Stand der Technik.

1 to 10 serve to explain the excellent properties of the methanol-based fuels according to the invention in more detail.

• 1 shows the dependence of the vapor pressure (absolute) of a fuel according to the invention with C ₄ - / C ₅ - / C ₆ hydrocarbon additive on the temperature for summer and winter quality for pure methanol and raw methanol.
• 2 shows the same dependency, with C ₄ , C ₅ -C ₇ hydrocarbons being added.
• 3 shows the same dependency, with C ₄ hydrocarbons and petrol being added (OK).
• 4 shows the same dependency with ethanol / water (95.6% by weight ethanol and 4.4% by weight H ₂ 0) and C ₄ - / ^C ₅ / ^C ₆ hydrocarbons as additives.
• 5 shows the same dependency as in FIG. 4, but with C ₄ and C ₅ -C ₇ hydrocarbons as an additive.
• 6 shows the same dependency as in FIGS. 4 and 5, but with C ₄ hydrocarbons and OK as an additive.
• In Fiq. 7 shows the dependence of the vapor pressure on the hydrocarbon concentration in general form.
• Fig. 8 corresponds to the curve of Fig. 7 for the exemplary case of the addition of C ₅ / C ₆ hydrocarbons to ethanol (95.6%).
• FIGS. 9 and 10 show comparative vapor pressure curves with isopentane addition to pure and raw methanol, in accordance with the prior art.

The fuels according to the invention are explained in more detail with the aid of the figures.

In Fig. 1, the vapor pressure of the fuel is pure or raw methanol and C ₄ - / C ₅ - / C ₆ hydrocarbons in mbar against the temperature range -30 to +30 ° C for winter and summer.

The compositions are given in Table 2, each in% by weight:

Dic Reid vapor pressures are 7CC mbar for summer fuels and 900 mbar for winter fuels.

The amounts of C ₅ and C ₆ hydrocarbons were kept constant for all mixtures.

If the Reid vapor pressure of a mixture of methanol and hydrocarbon additives is plotted at a constant temperature against increasing amounts of hydrocarbon additive, the vapor pressure initially increases almost linearly with increasing amount of hydrocarbon additive. With a certain amount of hydrocarbon addition, one reaches an area in which the vapor pressure increase drops sharply and, with further addition, continues almost horizontally.

This general behavior is shown in FIG. 7. A single curve is shown in FIG. 8 for a mixture of 95.6% by weight of ethanol and C _S / C ₆ hydrocarbon additives. If you keep the total amount of z. B. C _S / C ₆ hydrocarbons constant, but varies the ratio of C ₅ - to C ₆ hydrocarbons, so you get similar sets of curves.

It has proven to be advantageous with regard to the stability of the respective fuel, that is to say the lowest possible outgassing on the one hand while maintaining the desired vapor pressures of the fuels according to the invention in winter and summer operation on the other hand, the added amount of C5 / C6 or C ₅ C ₇ hydrocarbons or gasoline to be selected so that one is in the area below the transition to the almost horizontal vapor pressure area, as shown in Fig. 7.

The preferred or particularly preferred ranges of the hydrocarbon additive are indicated in FIG. 7.

2, the vapor pressure of the fuel is pure or raw methanol with the addition of C ₄ - / C - C ₇ hydrocarbons in mbar against the temperature range -30 ° C to +30 ° C for winter and summer.

The compositions are given in Table 3, in each case in% by weight:

Die Reid-Dampfdrucke sind für die Sommer-Kraftstoffe wiederum 700 mbar und für die Winter-Kraftstoffe 900 mbar.

Reid vapor pressures are 700 mbar for summer fuels and 900 mbar for winter fuels.

The amounts of the C ₅ -C ₇ hydrocarbons were kept constant for all fuels.

3 is the vapor pressure of the fuel pure or raw methanol with the addition of petrol in mbar against the temperature range -30 ° C - +30 ° C for winter and summer.

The compositions are given in Table 4, each in% by weight:

Reid vapor pressures are 700 mbar for summer fuels and 900 mbar for winter fuels.

Since Otto fuels (normal fuels) differ in composition in summer and winter quality, the "narrow" were not kept constant, but conventional summer and winter fuels were used in different amounts, although the preferred amounts according to FIG. 7 were used.

Figures 1-3 give surprising results for the person skilled in the art.

It is known that, compared to the use of isopentane, which corresponds to the prior art, lower vapor pressures in summer operation for the technical use of methanol or ethanol fuels than it corresponds to the addition of isopentane, and higher vapor pressures are required for winter operation.

The vapor pressures of the fuels according to the invention shown in the curves in FIGS. 1-3 are summarized in Table 5 for -30 ° C. and +30 ° C. They show that, for the person skilled in the art, the fuels according to the invention unpredictably ensure excellent vapor pressure behavior.

If pure methanol is considered, it is found that when isopentane is added according to the invention, a vapor pressure of 550 mbar is measured for summer fuel and a vapor pressure of 70 mbar for winter fuel.

A slight increase in the case of summer fuel based on pure methanol at +30 ° C occurs with the additions of ^C ₅ ^{/ C} ₆ , ^C ₅ - C ₇ and OK.

If one looks at the winter fuel, it is found that with the additions of C ₅ / C ₆ , C ₅ - C ₇ and gasoline according to the invention there are substantial increases in vapor pressure compared to isopentane for practical driving. This unexpected result makes a decisive contribution to the use of methanol fuels as alternative fuels.

In the case of raw methanol, the advantages according to the invention are even more pronounced.

In winter operation, a steam pressure of 110 mbar is obtained when isopentane is added. With C ₅ / C ₆ -, C ₅ - C ₇ - and OK addition, steam pressure increases of 30, 50 and 40 mbar are obtained.

These results clearly show that, compared to the prior art, significant unpredictable improvements have been achieved which make the practical use of methanol fuels possible even under extreme climatic conditions. If one looks at the explosion limits, which are shown in Table 6, it is found that, with regard to this parameter too, clear improvements are achieved with the fuels according to the invention compared to the prior art, namely the addition of isopentane.

Comparing the vapor pressures of Figures 4, 5 and 6 at 30 ° C (summer curve) or -30 ° C (winter curve) with the corresponding isopentane / pure methanol vapor pressures, it is found that under Reid conditions with ethanol (E 100) and additives C ₄ / C ₅ / C ₆ , C ₄ / C ₅ -C ₇ and C _{4 /} petrol (OK) an excellent vapor pressure behavior is obtained especially in winter operation.

The vapor pressures are summarized in Table 7.

Table 8 summarizes the compositions of the ethanol-based fuels according to the invention.

Very good results are also obtained with the ethanol-based fuels according to the invention with regard to the explosion limits, as can be seen from Table 9.

FIG. 8 shows, by way of example for the addition of C _S / C ₆ to ethanol on the basis of the general curve in FIG. 7, from which concentration ranges the preferred or particularly preferred sections a and b are taken.

The ratio of C _5: C ₆ in this example is 1: 1. _Ha t _is the concentration of C _{5 /} C _6, or C ₅ - C ₇ or OK 7 and 8, determined according to the concentration curve, it is much C ₄ added that the Reiddampfdruck is obtained.

However, it is known in the art, are that the Reid vapor pressures of 70 _{to 0} mbar (sammer) and 900 mbar (Winter) as a basis of comparison for the inventive power toffe preferred, but that the present invention also other summer or winter vapor pressures are chosen as base can.

The additives of the fuels according to the invention can be added, as is customary for alcohol-based fuels. Suitable corrosion inhibitors include e.g. those based on triazole, imidazole or benzoate.

As an ignition control additive, e.g. Tricresyl phosphate, but also others, can be used.

If necessary, emulsifiers such as glycols or their mono- and diether and others can be used.

Other additives are also possible according to the invention.

Undoubtedly, the interaction of the components according to the invention to form the new fuels based on pure, raw methanol and ethanol with previously unattainable properties, which can be produced if necessary from domestic raw materials, namely from coal synthesis gas or bioalcohol, is of the greatest economic importance.

Like the extensive investigations carried out by the applicant over many years and at great financial expense, in particular with isopentane additives, the use of which is due to the It was an unexpected result of the present invention to show that the prior art was particularly suitable that the fuels according to the invention meet all the requirements that are placed on a fuel in practice in such an outstanding, unrivaled manner.

Claims (14)

1. Fuels based on methanol with optionally up to 15% by weight of water in the fuel, characterized in that a mixture of C ₄ hydrocarbons and a mixture of C ₅ / C ₆ hydrocarbons is added to the methanol, a) the total amount of C ₄ and C ₅ / C ₆ hydrocarbons in the fuel is 0.1 to 15% by weight and b) the ratio of C _4: C ₅ / C ₆ , 1: 500 parts by weight to 3: 1 parts by weight. 2. Fuels based on methanol with optionally up to 15% by weight of water in the fuel, characterized in that a mixture of C ₄ hydrocarbons and a mixture of C ₅ -C ₇ hydrocarbons is added to the methanol, a) the total amount of C ₄ - and C ₅ - C ₇ hydrocarbons in the fuel is 0.1 to 18% by weight and b) the ratio of C _4: C ₅ - C _{7 'is} 1: 500 parts by weight to 3: 1 parts by weight. 3. methanol-based fuels, optionally with up to 15% by weight of water in the fuel, characterized in that a mixture of C ₄ hydrocarbons and gasoline is added to the methanol, a) the total amount of C ₄ hydrocarbons and gasoline in the fuel is 0.1 to 25% by weight and b) the ratio of C _4: gasoline, 1: 500 parts by weight to 3: 1 parts by weight. 4. Fuels according to claims 1-3, characterized in that the methanol used is undistilled technical methanol. 5. ethanol-based fuels, optionally with up to 25% by weight of water in the fuel, characterized in that a mixture of C ₄ hydrocarbons and a mixture of C ₅ / C ₆ hydrocarbons is added to the ethanol, a) the total amount of C ₄ and C ₅ / C ₆ hydrocarbons in the fuel is 0.1 to 15% by weight and b) the ratio of C _4: C ₅ / C ₆ , 1: 500 parts by weight to 3: 1 parts by weight. 6. ethanol-based fuels, optionally with up to 25% by weight of water in the fuel, characterized in that a mixture of C ₄ hydrocarbons and a mixture of C ₅ -C ₇ hydrocarbons is added to the ethanol, a) the total amount of C ₄ - and C ₅ - C ₇ hydrocarbons in the fuel is 0.1 to 18% by weight and b) the ratio of C _4: C ₅ - C _{7 'is} 1: 500 parts by weight to 3: 1 parts by weight. 7. ethanol-based fuels, optionally with up to 25% by weight of water in the fuel, characterized in that a mixture of C ₄ hydrocarbons and petrol is added to the ethanol, a) the total amount of C ₄ hydrocarbons and gasoline in the fuel is 0.1 to 25% by weight and b) the ratio of C _4: gasoline, 1: 500 parts by weight to 3: 1 parts by weight. 8. Fuels according to claims 5-7, characterized in that the ethanol used is technical water-containing ethanol. 9. Fuel according to claims 1-8, characterized in that it consists of a mixture of at least two of the fuels disclosed in claims 1-8. 10. Fuel according to claims 1-9, characterized in that it consists of a mixture of at least one of the fuels disclosed in claims 1-8 and a methanol-based fuel, which optionally contains up to 15% by weight of water and which is a mixture contains from C ₄ hydrocarbons and a mixture of C _S hydrocarbons, wherein a) the total amount of C ₄ and C _S hydrocarbons in the fuel is 0.1-15% by weight and b) the ratio of C _4: C ₅ hydrocarbons is 1: 500 parts by weight to 3: 1 parts by weight. 11. Fuel according to claims 1-10, characterized in that the methanol used is undistilled technical methanol. 12. Fuel according to claims 1-11, characterized in that it consists of a mixture of at least one of the fuels disclosed in claims 1-11 and a fuel based on ethanol, which optionally contains up to 25 wt.% Water and one Contains mixture of C ₄ hydrocarbons and a mixture of C _S hydrocarbons, wherein a) the total amount of C ₄ and C ₅ hydrocarbons in the fuel is 0.1-15% by weight and b) the ratio of C _4: C ₅ hydrocarbons is 1: 500 parts by weight to 3: 1 parts by weight. 13. Fuel according to claims 1-12, characterized in that the ethanol used is technical, water-containing ethanol. 14. Fuel according to claims 1-13, characterized in that it consists of a mixture of at least two of the fuels disclosed in claims 1-13.

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