CA1251643A - Motor-fuels - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
The instant invention relates to fuels based on methanol and/
or ethanol which contain additionally mixtures of C4-hydrocarbons with C5/C6- and/or C5 - C7-hydrocarbons and/or gasoline.

Description

~ 3 23769-38 Background of the Invention Field of the Invention The instant invention relates to fuels based on methanol and/or ethanol which contain additionally mixtures of C4-hydrocarbons with C5/C6- and/or C5 - C7-hydrocarbons and/or gasoline.

Description of the Prior Art Distilled ("pure") methanol has been extensively investigated as an alternate fuel for a number of years ~Chemicals Technologie, Wim~acker-Kuchler, Vol. 5, Organische Technologie I, 4. Ed. 1981, p. 517).
Higher alcohols and water as blending-components for methanol and ~he use of these blends as fuels are known (N. Iwai, The combustion of methanol mixed with water, Second Nato-Symposium; Nov. 4-8, 1974, Dusseldorf).
In US-Patent 23 65 009 combinations of alcohols with 1 to 5 C-atoms with saturated and unsaturated hydrocarbons with 3-5 C-atoms as fuels are described.

0~

- 2 - - UK 354 -The same applicant discloses in Continuation in part US-PS 24 04 094, fuels, which either consist of absolutely pure methanol or commercial, refined methanol, which is free of water (column 6, lines 8-11) in combination with ali-phatic C3 - C5 hydrocarbons. This Patent also claims a methanol fuel, which contains 2 - 20 ~ of an aliphatic C4 - or C5-hydrocarbon. According to column 5, lines 22-27, hydrocarbons in highly purified form are preferred.
Furthermore the hydrocarbons used, may be partly unsaturated (column 5, lines 28-3A)~ The examples disclose (table 1) as added hydrocarbons n-pentane, iso-pentane and a C~-cut, which contains up to 20 ~ of butenes. According to claims 5 and 6 a mixture of saturated C5-hydrocarbons can be used for the special case of a fuel for the cold start of aviation engines.
In US-PS 2,365,009 also mixtures of ethanol with aliphatic C3 - C5-hydrocarbons are described, whereby the aliphatic hydrocarbons may be either saturated or unsaturated and whereby isopentane (claim 8 and table 1) is preferred.
Further disclosur~ of ethanol1hydrocarbon mixtures are DE-OS 28 06 673 and DE-OS 32 11 775.
It is well known to the artisan that in certain countries, with a high supply of ethanol, for example in Brazil, etha-nol is used in pur~ form as well as in mixtures with gaso-line as a fuel (Chemical Engineering Progress, April 1979, page 11).

On the other hand it is also known that the lowPr alcohols have specific disadvantages with regard to their use as fuel,for example bad cold start behavior, bad driving behavior at low outside temperature, unsatisfactory mixing in parti-cular with hydrocarbons at low temperatures and the broad explosibility limits.
The cause of the cold-start problems, in particular at low temperatures, is to be sought in the low ignitibility of methanol nd ethanol.

'~ ~"~ 3

- 3 - - UK 354 -A measure for the ignitibility is the vapor pressure of a motor-fuel, which is determined by the so-called Reid-Test at 37,7 C. Methanol for example has a Reid vapor pressure (RVP) of 350 mbar, whereas gasoline has a Reid vapor pressure of 700 mbar.
At an outside temperature below 15 C the vapor pressures of methanol and ethanol are too low for the formation of ignitible gasphase mixtures.

The explosibility limits for pure (distilled) methanol in air are 6,75 to 36,7 percent by volume resulting in an ex-plosive mixture of fuel and air in the gasphase in the fuel tank between ~15 and +25 C. Addition of 6 to 9 percent by weight of isopentane reduces the upper explosibility limits to -7 C at summer temperature and -20 C at winter tempera-ture. As a result the safety problems are essentially avoi-ded. In the state of the axt isopen~ane has been considered therefore and because of its excellent solubility in methanol as well as in ethanol in particular at low temperatures as the preferred additive (isopentane is 2~methylbutane).

The most favorable adjustment of the vapor pressure ofneat me-thanol has turned out to be 700 mbar for summer- and 900 mhar for winter-fuel ~which are the upper vapor pressure values of the German fuel DIN-Norm 51600).

In consideration of the problems described above and in consideration of the state of the art and as a consequence of continued investigations, isopentane (2-methylbutane) has been hitherto selected as the optimum hydrocarbon additive.

The fuel consisting of distilled (refined) methanol and isopentane, which is ~nown as ~ 100 fuel has been tested in extensive field tests for several years, in particular in municipal car fleets in the Federal Republic of Germany (s. H.Muller, 27th DGMK-Conference, 6th to 8th of October, 1982).

- 4 ~ 23769-38 Although methanol, which contains isopentane, meets to a certain extent the expectations with regard to a reliable motor-fuel, the tests have unexpectedly shown that there still remain substantial disadvantages.
In particular during operation at summer temperatures the vapor pressure by using methanol/isopentane mixtures is too high even after reduction of the isopentane-content to 5-6 weight percent, accompanied by undesirable degassing of isopentane.
Whereas at winter temperatures despite an isopentane content of up to 9 percent by weight a decrease of the vapor pressure is observ-ed which leads to bad cold start behavior at temperatures below -1 oC.
Object of the present invention therefore was to make fuels available, based on methanol and ethanol, resulting in an im-proved driving behavior in particular at relatively high and relat-ively low outside temperatures, as required in practical operation of a motor-vehicle and which would simultaneously permit safe operation, avoiding the formation of an explosive mixture inside of the fuel tank.
Summary of the Invention According to the present invention there is provided a motor fuel based on methanol or ethanol containing methanol or ethanol or both and a mixture of C4-hydrocarbons and another hy-drocarbon selected from the group consisting of a mixture ofC
carbons or C6-hydrocarbons, a mixture of c5-c7-hyclrocaxhons and gasoline, wherein - 4a - 23769-38 a) the total amount of C4-hydrocarbons and C5 or C6-hydrocarbons in the full amounts to 0.1 to 15 weight-~; the total amount of C4- and C5 - C7 -hydrocarbons in the fuel amounts to O.l to 18 wei~ht-%; for the total amount of C4-hydrocarbons and gasoline in the fuel amounts to O.l to 25 weight-%, and b) the ratio of C4-hydrocarbons: the other hydrocarbon is 1:500 parts by weight to 3:1 parts by weight.
One embodiment of the invention provides a motor-fuel based on methanol which may optionally contain up to 15 percent by weight of water, and contains additionally a mixture of C4-hydro-carbons and a mixture of Cs/C6- or Cs - C7 -hydrocarbons or gasoline, wherein the total amount of C4-hydrocarbons and C5C6- or C5 - C7 -hydrocarbons or gasoline in the motor fuel amounts to O.l to either 15~, 18% or 25~ by weight and the ratio of C4 : Cs/C6-or C5 - C7 -hydrocarbons or gasoline is 1 : 500 to 3 : 1 parts by weight.
Another embodiment provides a motor-fuel based on ethanol which may optionally contain up to 25 percent by weight of water, and con-3~

tains additionally a mixture of C5/C6- or C5 - C7-hydrocarbons or gasoline, wherein the total amount of C4-hydrocarbons and C5/C6- or C5 - C7- hydrocarbons or gasoline i.n the motor fuel amounts to 0.1 to either 15%, 18% or 25% by weight and the ratio of C4 : C5/C6- or C5 - C7-hydrocarbons or gasoline is 1 : 500 to 3 : l parts by weight~
Still another embodiment provides a motor-fuel consisting of a mixture of a fuel based on methanol and/or ethanol containing a mixture of C4-hydrocarbons and C5-hydrocarbons wherein the total amount of C4- and C5-hydrocarbons in the fuel amounts to 0~1 to 15 weight-% and the ratio of C4 :
C5 is l : 500 parts by weight to 3 : 1 parts by weight.
Description of Specific Embodiments The present invention leads to the surprising result that mixtures of C4-hydrocarbons and C5/C6- and/or C5 - C7-hydrocarbons and/or gasoline with pure (distilled or refined) methanol as well as with "crude" (non-distilled) methanol and with ethanol resp. technical ethanol which contain water or mixtures thereof meet the above named requirements in superior, hitherto not attainable manner. In particular it was non-obvious for the artisan that the combination of the desired properties could be obtained including safe explosion limits, sufficiently little degassing at high outside temperatures despite the addition of a relatively high water content which also means at a climate of very high humidity, no phase-separation of the fuel mixture, excellent cold-start behavior and driving behavior at low outside temperature as well as high outside temperature, which is a basic necessity for the practical use of alternative fuels.

~,~c~

It was a particularly surprising result that technical streams of C4-, C5-, C6- and C7-hydrocarbons which are formed for example in refinexies and production units for bulk che-micals like ethylene and benzene/toluene (BT), as well as gasoline are excel1ently suited despite of differing com-positions with regard to individual hydrocarbons. The total amount of C4-, C5/C6-, and C5 ~ C7-hydrocarbons and gasoline can be 0,1 to 15 % (C4, C5/C6), 0,1 to 18 % (C4, C5 - C7) and 0,1 to 25%~gasoline) by weight, whereby a total amount of 1 - 12 ~, 1 - 16 % and 1 -20 % is preferred.
The ratio of C4- to C5/C6- to C5 - C7-hydrocarbons and to gasoline is 1 : 500 to 3 : 1, a ratio of 1 : 1 to 1 : 20 being preferred.

Small amounts of non C4-, non-C5-, C6- and C7-hydrocarbons as inevitably present in technical streams can be present in the inventive fuels~ independent of wether theses hydro-carbons are aromatic or non-aromatic. Suitable streams are exemplarily represented in the following analyses:

~-stream C5-stream c32,4~ by weight c4 0,56% by weight C4 unsaturated0,5 " C5 unsaturated 1,38 isobutane34,9 " isopentane 28,15 "
n-butane 62,0 " n-pentane 30,31 "
> C~ 0,2 " cyclopentane 27,3 "
~ C5 12,3 ~

6~3 C6-stream n-butane 1,0 by weight cyclopentane 1,6 "
2-methylpentane 2,5 "
3-methylpentane 3,0 "
2-ethylbutene 11,2 "
methylcyclopentane32,0 "
benzene 29,2 "
cyclohexane 7,4 "
2-methylhexane 1,5 "
3-methylhexane 1,1 "
others 9,5 "

C7-stream n-heptane 2,2 by weight methylcyclohexane 15,3 "
1-methylhexene 1,2 "
ethylcyclohexane 10,7 "
ethycyclopentane 18,2 "
1,3-dimethylpentene 8,2 "
toluene 30,1 2,4-dimethylpentane 4,5 "
others 9,6 "
Gasoline can be regular as well as premium quality. In general, gasoline consits of C5 to C12-hydrocarbons and has a S~ 3 - 7a - 2376~-38 a boiling point in the range of approximately 60 to 210C. It is possible in the case of the fuels of the present invention in anal-ogy to other known alternative fuels, to add certain amounts of other conventional components for example C3-, C4- and higher alcohols, ethers, like methyl-tert.- butylether and other readily available ethers, furthermore, ketones, like acetone, as well as aromatic components like benzene, toluene and xylene.

~ 3 ~ 8 - UK 354 -According to the state of the art fuPls based on methanol have been prepared with dis~illed refined methanol resp.
so-called "pure" methanol. It is known to the artisan, that high re~uirements with regard to purity of distilled (pure) methanol exist which are met by a corresponding high opera-tional effort, in particular in the distillation step.

With regard to certain technical problems, which are encoun-tered with methanol fuel for example corrosive and dissolving effects of methanol on parts of the motor-vehicle, like tubing, tank lining, certain motor-parts, and motor con-struction material and furthermore high requirements with regard to complete combustion as a consequence of increasing environmental protection provisions, accompanied hy the re-quirement of avoiding deposits in particular in motor and carburator, the artisan has hitherto assumed that non-di-stilled methanol as produced in low- ! middle- or high pressure methanol production units is unsuited for the use as motor fuel.

Non-distilled, so-called crude methanol, is known to contain besides water a number of contaminations like formaldehyde, methylformiabe,formic acid, dimethylsulfide,formaldehyde,di-methylacetale, iron pentacarbonyle,various carboxylic acids and esters.

It has been a non-obvious result of the investigations of applicant, that in contrast to the prejudice of the artisan non-distilled methanol is excellently suited as a fuel in the inventive fuel mixture, in particular with regard to the effects on those parts of the motor vehicle which are in contact with the fuel as well as with regard to emissions.
Surprisingly it has been found that the emissions of CO, NOx and hydrocarbons axe even lower compared to distilled Ipure) m hanol. This i5 ~hown in the following table:

~.~S ~3 _ g _ - ~c 354 -~n ~P ~ Ln ~ ~
_--r ~_ ~
_~0 _ _ ~ ~ ~ n o ~
~ 'r ~ __ ~_ C~n d~ ~ Ln ~ ~
~ ~ o ~
'~ C~u~ _ . __ ~ ~n !>1~ ~ ~D ~
o . _ ~-- L' __ n Ln il _ ~ 8~ ~ L~

~S~6~

According to the invention also topped crude methanol can be used, which contains less of low vapor pressure contaminations.

The excellent properties of the inventive fuels are further illustrated with the aid of flgures 1 to 10:

Fig. 1 represents the dependence of the vapor pressure (abso-lute) of an inventive fuel which contains C4-/C5-/C6-hydrocarbons on the temperature for summer and winter grade with "pure" and "crude" methanol (table 2).
Fig. 2 represents the same dependence as Fig. 1 with C4/C5-C7-hydrocarbons added.
Fig. 3 represents the same dependence with C4-hydrocarbons and gasoline added.
Fig. 4 corresponds to Fig. 1 with ethanol (95,6~ by weight ethanol and 4,4 % by weight of H20) instead of methanol Fig. 5 corresponds to Fig. 2 with ethanol (95,6~ by weight ethanol and 4,4 % by weight of ~2) instead of methanol Fig. 6 corresponds to Fig. 3 with ethanol (95,6% by weight ethanol and 4,4 % by weight of H20) instead of methanol Fig. 7 represents in a general manner the preferred range of added hydrocarbon ~uantities.
Figq 8 represents the preferred range of added hydrocarbons in the particular case of ethanol (95,6 %) and C5/C6-hydrocarbons ~ 6~3 ~ UK 354 -Fig. 9 and 1C represent vapor pressure curves for comparison purposes with isopentane-additions on a "pure" and "crude"-methanol basis in accordance to the ~tate of art.

In Fi~. 1 the vapor pressure is expressed in mbar. The tempe-rature rangeinvestigated is between -30 C to +30 ~C for winter and summer fuels.
Table 2 represents the compositions in weight percent for C4/C5/C6 addition.

Table 2 mPeUtheanol ~ C5 C6 mtrhdanol C4 C5 C6 . __ summer 92,1 0,9 3,5 3,5 92,7 0,3 3,5 3,5 ~ .
~inter 90,9 2,1 3,5 3,5 91,9 1!1 3,5 3,5 I . . I I _ .

The Reid vapor pressures are as in the comparative example of isopentane-addition 700 mbar for summer and 900 mbar for winter grade. The quantities of C5- and C6-hydrocarbons are the same for all mixtures.

If the Reid vapor pressure of a mixture of methanol and hydro-carbons is plotted against increasing quantities of hydro-carbons in the mixture at constant temperatur (Reid-tempera-ture) th apor pressure at the beginning rises almost ~ r linearly with increasing quantities of added hydrocarbons. At a particular quantity of hydrocarbons, a rangeis observed in which the vapor pressure increase pronouncedly terminates. With further addition of hydrocarbons, the curve continues almost horizontally.
This general behavior is presented in Figure 7.
A specific diagram is represented in Figure 8 represent-ing the vapor pressure dependence of an ethanol/C~--/C6-hydrocarbon mixture.
If the total quantity of for example C5- and C6-hydro-carbons is kept constant, but the ratio of C5- to C6-hydrocarbons is varied, an analogous family of curves is obtained.
It has proven to be advantageous with regard to the stability of the individual fuels that is with regard to a minium of degasing on the one hand combined with the desired vapor press-ures of the inverltive fuels during winter and summer operation on the other hand to choose such a quantity of c5-c6-hydrocarbons, C5-c7-hydrocarbons~ or gasoline to be added, that one is positioned in the range of transition from the rising part of the curve to the almost horizontal part of the curve represented in Figure 7.
The preferred resp. particularly preferred ranges are indicated in Figure 7a and b.
Figure 2 represents the vapor pressure of fuels consist-ing of "pure" resp. "crude" methanol with added C4-/C5 - c7-hydro-carbons in mbar plotted against the temperature range of -30C to +30C for winter and summer operation.
Table 3 contains the compositions in weight-% of these mixtures.

~ 3 Table 3 _ . ; . _, methanol C4 C5C6 C7 CreUthanol C4 C5 C6 C7 . . . ,.. . _ _ mer 92,3 0,7 4,51,S 1,0 92,9 0,1 4,5 1,5 1,0 ~ nter 91,2 1,8 4,51,5 1,0 92,1 0,9 4,5 1,5 1,0 .

Again the Reid vapsr pressures are 700 mbar for summer opera-tion and gO0 mbar for winter operation.
The quantities of C5- to C7-hydrocarbons have been kept con-stant for the different mixtures.

In Fig. 4 the vapor pressure of fuels based on "pure" resp.
"crude" methanol with added gasoline in mbar is plotted against the temperature range of -30 C to +30 C for winter and summer operation.
Table 4 contains the compositions of the fuels in weight-~.

Table 4 = pure C4 ~-1~ cw~ C4 su 2r 8717 1,1 11,2 90,2 0,9 8,9 winter 82,8 1, 8 15, 4 86, 6 1, 6 11, 8 The Reid vapor pressures are 700 mbar for summer operation and 900 mbar for winter operation.
Since gasoline compositions are different for winter and summer operation, the added quantities have not been kept constant, but common summer and winter gasoline fuels have been added in variing quantities, in the range of the pre-terred qua ities represented in Fig. 7.

Fig. 1 to 3 exhlbi-t surprising results for the artisan.
It is Xnown that with respect to the addition of isopentane, which represents the state of the art, lower vapor pressures of methanol or ethanol fuels for su~ner operation and higher vapor pressures for winter operation are necessary for the prac-tical use of such fuels in the public domain.
The vapor pressures of the inventive fuels represented in the diagrams of Figures 1 to 3 are summarized in table 5.
The data show that non-obvious to the artisan the inventive fuels exhibit an excellent vapor pressure behavior.

Ta~le _ (based on Reid vapor pressure, 700 mbar for summer and 900 mbar for winter operation deter-mind at 37,7 C) .... ...... _ _ ... _._ ............... ..... . __ ,, pure crude me-thanol methanol 30 C summér 550 mbar 620 mbar ...
Isopentane, -30 C, winter 70 mbar 110 mbar C4/C5/C6 ' - ---~ . .
0 555 mbar 565 mbar 30 C su~ner _ 9~~5' 6' 100 mbar 140 ml~ar -30 C winter C4/ 5 C7, 580 mbar 595 mbar 0 9C summer C4/C5 - C7, -- .. ._ -30 C winter 100 mbar 160 mbar C~/OK,* 570 mbar 590 mbar 0 C summer C~/OK, -30 C winter 100 mbar 150 mbar "Otto-Kraftstoff", i,e,m a motor fuel (gasoline) for Otto-engines.
~;

6k~3 14a - - UK 354 -Considering pure methanol one notices that the inventive addi-tions of C4-hydrocarbons in combination with the higher hydro-carbons, in the particular case of isopentane lead to a vapor pressure of 550 bar for summer fuel and 70 mbar for winter fuel.
Only a slight increase is obs~rved with added C4/C5/C6- and C4/C5 - C7 or C4/yasoline for summer fuel.
If however winter fuels are considered one observes that the inventive additions of C~/C5/C6- and C4/C5 - C7-hydrocarbons resp. of C4/gasoline lead to a surprising and for practical purposes very importAnt increase of the vapor pressures compared to isopentane-addition namely of an increase of 30 mbar for winter quality based on pure methanol and o 30, 50 and 40 mbar for winter quality based on crude methanol.

~ ' ~ 3 These certainly non-obvious results are a decisive contribu-tion with respect to the introduction of neat methanol and ethanol fuels to the public domain where reliable properties of fuels are necessarv even under extreme climatic conditions.
The explosibility limits are represented in table 6. One ob-serves that the inventive fuels in comparison to the addition of isopentane exhibit broader ranges than the state of the art.

Table 6 (~ased on Reid vapor pressure) _ _ Upper pu:re iso- C4/C5/C6 C4 /C5~7C4 /gasolin~
explosion- methanol pentane t~rature C C C C C
_ r ~25 -7 ~-~0 ~-20 ~-20 winter ~15 -20 ~-25 ~-25 <-25 Comparison of the vapor pressures of figures 4, 5 and 6 at 30 C (summer curves) and ~30 C (winter curves~ with the corresponding isopentane/"pure methanol" vapor pressures shows that under Reid conditions also with ethanol (E 100) and additions of C4/C5/C6, C4/C5 - C7 and C4/gasoline an excellent vapor pressure behavior in particular for winter operation is observed.

The vapor pressures are summarized in table 7.

Table 7 (Reid vapor pressure basis) 700 mbar at summer and 900 mbar at winter operation, determined at 37,7 C.
_ , Ethanol 95,6 ~
.
C4/C5/C6 580 mbar summer 30 C
C4/C5/C6 95 mbar winter -30 C
C~ /C~ - C7 - .
summer 30 C 552 mbar C4 5 7 105 mbar winter -30 C
.
C4/OK 560 mbar summer 30 C
C4/OK 103 mbar winter - 30 C

Table 8 summarizes the compositions of the in~enti~e fuels based on ethanol.
Table 8 . 9t5ha6n%l C4 C5 C6 C7 OK
_ _ _ Summer89,0 2,0 4,5 4,5 Winter87,5 3,5 4,5 4,5 .
Summer89,3 1,7 5,5 2,5 1,0 Winter87,5 3,5 5,5 2,5 1,0 _ Summer81,6 2,4 16,0 Winter76,5 3,5 20,0 I_ l I . ~ ~ -Excellent results are obtained with the inventive fuels with regard to the explosibility limits, as shown in table 9.
Table 9 Upper _ temperature C4/C5/C6 C9/C5 - C7 C4/OK
Summer ~-20 C ~-20 C ~-20 C
_ _ _ .
Winter (-25 C <~75 ~C <-25 C

Fi~. ~ shows examplarily the addition of C5tC6 to ethanol on the basis of the general curve o Fig. 7, and how the preferred resp. particularly preferred ranges a and b are selected.
The ratio of C5 : C6 is 1 : 1 in this example. If the con-centration of C5/C6, resp. C5 - C7, resp. OK has been deter-mind according to curve 7 resp. 8, C4 i5 added in such a quantity in order to obtain the desired Reid vapor pressure.
It is known to the artisan that the Reid vapor pressures of 700 mbar (summer) and 900 mbar (winter) are preferred as a basis for comparison for the inventive fuels, that however other basic vapor pressures could also be used for compara-tive purposes within the scope of the instant application and the disclosed fuels.

The use o additives in the case of the inventlve fuels can be as usual foralcohol-Euels. Sui-table corrosion inhibitors are for example triazol-, imidazol- or benzoate-derivatives.
Ingnition control additives may be tricresyl phosphate as well as other common formulations. Optionally, emulsifying agents can be used like glykols or glykolmono or diethers.

~.5~
- 18 - UK 354 - ¦

Further additiv additions are within the scope of the in-stant application.
It is to be emphasized that the s~nergistic effects of the inventively combined components resulting in -the inventive fuels based on "pure" (distilled), and "crude" (non-distilled) methanol and ethanol, lead to fuels with hitherto non-attainable properties. These fuels which can be produced not only from mineral oil but also from coal and bioethanol, are of greatest economic importance.
It is a non obvious and surprising result of the instant invention that the inventive fuels combine the desired properties in such an excellent way.

Claims (18)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A motor-fuel based on methanol or ethanol containing (i) methanol or ethanol or both, (ii) a mixture of C4-hydrocarbons and (iii) another hydrocarbon selected from the group consisting of a mixture of C5 or C6-hydrocarbons, a mixture of C5-C7-hydrocarbons and gasoline, wherein a) the total amount of C4-hydrocarbons and C5 or C6-hy-drocarbons in the fuel is 0.1 to 15 weight-%; the total amount of C4-hydrocarbons and C5 - C7-hydrocarbons in the fuel is 0.1 to 18 weight -%; or the total amount of C4-hydrocarbons and gasoline in the fuel is 0.1 to 25 weight-%, and b) the ratio of C4-hydrocarbons: the other hydrocarbon is 1:500 parts by weight to 3:1 parts by weight.

2. A motor-fuel based on methanol which comprises methanol, a mixture of C4-hydrocarbons and a mixture of C5 or C6-hydrocarbons, wherein a) the total amount of C4- and C5 or C6-hydrocarbons in the fuel is 0.1 to 15 weight-% and b) the ratio of C4-hydrocarbons: C5 or C6-hydrocarbons is 1:500 parts by weight to 3:1 parts by weight.

3. A motor-fuel based on methanol, which comprises methanol, a mixture of C4-hydrocarbons and a mixture of C5 - C7-hydrocarbons, wherein a) the total amount of C4- and C5 - C7-hydrocarbons in the fuel is 0.1 to 18 weight-% and b) the ratio of C4-hydrocarbons: C5-C7-hydrocarbons is 1:500 parts by weight to 3:1 parts by weight.

4. A motor-fuel based on methanol, which comprises methanol, a mixture of C4-hydrocarbons and gasoline, wherein a) the total amount of C4-hydrocarbons and gasoline in the fuel is 0.1 to 25 weight-%, and b) the ratio of C4-hydrocarbons: gasoline is 1:500 parts by weight to 3:1 parts by weight.

5. The motor-fuel according to claim 2, 3 or 4, which further contains up to 15 weight-% of water based on the methanol.

6. The motor-fuel according to claim 2, 3 or 4, wherein the methanol used is non-distilled technical methanol.

7. A motor-fuel based on ethanol, which comprises ethanol, a mixture of C4-hydrocarbons and a mixture of C5 or C6-hydrocarbons, wherein a) the total amount of C4-hydrocarbons and C5 or C6-hydro-carbons in the fuel is 0.1 to 15 weight-%, and b) the ratio of C4-hydrocarbons: C5 or C6-hydrocarbons is 1:500 parts by weight to 3:1 parts by weight.

8. A motor-fuel based on ethanol, which comprises ethanol, a mixture of C4-hydrocarbons and a mixture of C5 - C7-hydrocarbon wherein a) the total amount of C4- and C5 - C7-hydrocarbons in the fuel is 0.1 to 18 weight-% and b) the ratio of C4-hydrocarbons: C5 - C7-hydrocarbons is 1:500 parts by weight to 3:1 parts by weight.

9. A motor-fuel based on ethanol, which comprises ethanol, a mixture of C4-hydrocarbons and gasoline, wherein a) the total amount of C4-hydrocarbons and gasoline in the fuel is 0.1 to 25 weight-% and b) the ratio of C4-hydrocarbons: gasoline is 1:500 parts by weight to 3:1 parts by weight.

10. The motor-fuel according to claim 7, 8 or 9, which fur-ther contains up to 25 weight-% of water based on the ethanol.

11. The motor-fuel according to claim 7, 8 or 9, wherein characterized in that the ethanol used is a water-containing, tech-nical ethanol.

12. A fuel according to claim l which contains both methanol and ethanol.

13. The fuel according to claim l, which comprises methanol, a mixture of C4-hydrocarbons and a mixture of C5-hydrocarbons, wherein a) the total amount of C4-hydrocarbons and C5-hydrocar-bons in the fuel is 0.1 to 15 weight-%, and b) the ratio of C4-hydrocarbons: C5-hydrocarbons is 1:500 parts by weight to 3:1 parts by weight.

14. The fuel according to claim 13, wherein the methanol used is a non-distilled technical methanol.

15. The fuel according to claim 13, which further contains up to 15 weight-% of water based on the methanol.

16. The fuel according to claim 1, which comprises ethanol, a mixture of C4-hydrocarbons and a mixture of C5-hydrocarbon wherein a) the total amount of C4-hydrocarbons and C5-hydrocar-bons in the fuel is 0.1 to 15 weight-% and b) the ratio of C4-hydrocarbons: C5-hydrocarbons is 1:500 parts by weight to 3:1 parts by weight.

17. The fuel according to claim 16, wherein the ethanol used is a water-containing technical ethanol.

18. The fuel according to claim 16 which further contains up to 25 weight-% of water based on the ethanol.