Motor fuel composition

A clear stable motor fuel composition having an improved octane rating comprising alcohol selected from the group consisting of methanol in the amount of about 2.0 to 5.0 vol. %, ethanol in the amount of about 2.0 to 10.0 vol. %, and mixtures thereof in the amount of about 3 to 9.0 vol. %, about 2.0 to 10 vol. % of a cosolvent alcohol selected from the group consisting of tertiary butyl alcohol, isopropanol, and mixtures thereof; water to provide a total water concentration of about 0.1 to 0.5 wt. % (basis motor fuel composition); about 0.01 to 2.0 weight percent (basis motor fuel composition) of a nonionic surfactant represented by the formula alpha-hydro omega-hydroxy-poly (oxyethylene) poly (oxypropylene) poly (oxyethylene) block copolymer; and the balance comprising the base fuel gasoline.

FIELD OF THE INVENTION 
This invention relates to fuels for internal combustion engines and more 
particularly to a novel clear stable gasoline-alcohol-water motor fuel 
composition. 
The use of aliphatic alcohols such as methanol and ethanol to extend 
gasoline fuels while imparting a higher octane rating to the gasoline has 
been long attempted. Alcohol-gasoline blends have a low tolerance for 
water that is encountered in the blending and distribution systems. 
Methanol-gasoline blends are much less water tolerant than 
ethanol-gasoline blends. Unstable hazy blends may result when water is 
present in such systems. Hazy gasolines are unacceptable by the public 
since they may indicate that something is wrong with the product. For 
example, the fuel may be contaminated. Further, phase separation may occur 
with water separating out and contributing to corrosion problems and motor 
starting difficulties. 
On the other hand, it has been recognized that some water in the gasoline 
is desirable since the presence of water will reduce the Octane 
Requirement Increase (ORI), and will increase the Octane Rating (OR). 
Advantageously, by the subject invention gasoline may be extended and its 
performance improved by the addition of alcohols and water without 
producing haze and separation of the constituents. 
U.S. Pat. No. 3,876,391 discloses clear motor fuel microemulsions 
comprising gasoline, water, two different surfactants and a water soluble 
and insufficiently gasoline soluble additive. No alcohol is present. U.S. 
Pat. No. 4,384,872 discloses a motor fuel composition comprising gasoline, 
alcohol and an interfacial modifying agent. No water is present. 
SUMMARY OF THE INVENTION 
In accordance with the invention there is provided a clear stable 
gasoline-alcohol-water motor fuel composition comprising a mixture of an 
alcohol selected from the group consisting of methanol in the amount of 
about 2.0 to 5.0 volume percent, ethanol in the amount of about 2.0 to 
10.0 volume percent, and mixtures thereof in the amount of about 3.0 to 
9.0 volume percent, about 2.0 to 10 volume percent of a cosolvent alcohol 
selected from the group consisting of tertiary butyl alcohol, isopropanol, 
and mixtures thereof; water to provide a total water concentration of 
about 0.1 to 0.5 weight percent; about 0.01 to 2.0 weight percent of 
surfactant which is represented by Formula I as follows: 
##STR1## 
where: a+c is an integer in the range of about 8.0-16.0, and b is an 
integer in the range of about 12-22; and the balance thereof being 
gasoline. Preferably, the volumetric ratio of teritary butyl alcohol 
and/or isopropanol to methanol and/or ethanol in the subject clear stable 
motor fuel composition is in the range of about 0.3 to 3.0, such as about 
0.5 to 2.0. 
This invention also provides a process for operating an internal combustion 
engine, supplying thereto, and combusting therein the above motor fuel 
composition. 
DISCLOSURE OF THE INVENTION 
The subject invention deals with clear stable motor fuel compositions 
comprising gasoline, at least two different alcohols, water and a 
surfactant. The surfactant more specifically comprises an alpha-hydro 
omega-hydroxy-poly(oxyethylene)poly(oxypropylene)poly(oxyethylene) block 
copolymer. A low dosage e.g. about two weight percent or less of the 
surfactant will solubilize the water and form a microemulsion. The 
microemulsion is of the "water-in-petroleum" type in which the average 
particle diameter of the dispersed phase is about 0.1 micron or smaller. 
Clear stable gasoline-alcohol-water motor fuel compositions having 
upgraded performance characteristics are thereby provided. 
The stable gasoline-alcohol-water motor fuel composition comprises a 
mixture of an alcohol selected from the group consisting of methanol in 
the amount of about 2.0 to 5.0 volume percent, ethanol in the amount of 
about 2.0 to 10.0 volume percent, and mixtures thereof in the amount of 
about 3.0 to 9.0 volume percent, about 2.0 to 10 volume percent of a 
cosolvent alcohol selected from the group consisting of tertiary butyl 
alcohol, isopropanol, and mixtures thereof; water to provide a total water 
concentration of about 0.1 to 0.5 weight percent (basis motor fuel 
composition), such as about 0.30 to 0.40 wt. %, about 0.01 to 2.0 weight 
percent such as about 0.02 to 0.50 wt. % say about 0.10 to 3.0 wt. % 
(basis motor fuel composition) of a surfactant represented by Formula I to 
be further described, and the remainder is a gasoline base fuel. 
Preferably, the volumetric ratio of tertiary butyl alcohol and/or 
isopropanol to methanol and/or ethanol in the subject clear stable motor 
fuel composition is in the range of about 0.3 to 3.0, such as about 0.5 to 
2.0. 
In one embodiment, the subject clear stable motor fuel composition may be 
prepared as follows: 
Mixture A is prepared by mixing together an alcohol selected from the group 
consisting of methanol in the amount of about 2.0 to 5.0 vol. %, such as 
about 2.70 to 4.75 vol. %, ethanol in the amount of about 2.0 to 10.0 vol. 
%, such as about 4.75 to 9.0 vol. %, and mixtures thereof in the amount of 
about 3.0 to 9.0 vol. %; about 2 to 10 vol. %, such as about 4.75 to 6.3 
vol. % of a cosolvent alcohol selected from the group consisting of 
tertiary butyl alcohol, isopropanol, and mixtures thereof; and water to 
provide a total water concentration of about 0.1 to 0.5 weight percent 
(basis motor fuel composition), such as about 0.30 to 0.40 wt. %. A hazy 
motor fuel composition is obtained when Mixture A and the base fuel 
gasoline, substantially comprising the remainder of the motor fuel 
composition, are mixed together. Further, about 0.01 to 2.0 weight percent 
(basis motor fuel composition) of a surfactant to be more fully described 
is added during the blending of Mixture A with the gasoline. Agitation is 
continued until the clear stable gasoline-alcohol-water motor fuel 
composition of this invention is made. The clear dispersion produced is a 
microemulsion. 
The aforesaid improved surfactant which is used in the subject clear stable 
motor fuel composition comprises an alpha-hydro 
omega-hydroxy-poly(oxyethylene)poly(oxypropylene)poly(oxyethylene) block 
copolymer having the structural Formula I as follows: 
##STR2## 
where: a+c is an integer in the range of about 8.0-16.0, such as about 
11.9-15.9, and b is an integer in the range of about 12-22, such as about 
18.1-21.1; and the balance comprising the base fuel gasoline. Preferably, 
the volumetric ratio of tertiary butyl alcohol and/or isopropanol to 
methanol and/or ethanol in the subject clear stable motor fuel composition 
is in the range of about 0.3 to 3.0, such as about 0.5 to 2.0. The 
molecular weight of said surfactant is in the range of about 1200 to 1750. 
Any gasoline suitable for a spark-ignited internal combustion engine can be 
extended and its octane rating increased by being blended with water and a 
specific alcohol or mixture of alcohols in accordance with the practice 
of this invention. Clear stable gasoline-alcohol-water motor fuel 
compositions are thereby produced. In general, the base fuel will consist 
of a mixture of hydrocarbons in the gasoline boiling range i.e., boiling 
from about 75.degree. to 450.degree. F. The hydrocarbon components may 
consist of paraffinic naphthenic, aromatic and olefinic hydrocarbons. This 
gasoline can be obtained naturally or it may be produced by thermal or 
catalytic cracking and/or reforming of petroleum hydrocarbons. The base 
fuel will generally have a Research Octane Number above 85 and up to about 
102 with the preferred range being from about 88 to 95. The clear stable 
gasoline-alcohol-water motor fuel composition of this invention will 
generally have a Research Octane Number above 90 and up to about 97, such 
as about 91 to 96. 
In most cases, water from an external source will be introduced into the 
motor fuel composition to supplement any water that may be dissolved in 
the alcohol and/or gasoline. Sources of water include purified deionized 
water, and bottom phase water e.g. process water that sinks to the bottom 
of a gravity separation tank containing gasoline. 
In another embodiment, gasoline contaminated with water may be processed 
into an upgraded clear stable motor fuel. In such case, the gasoline-water 
mixture is mixed with a mixture of the aforesaid alcohols, any additional 
water, and a surfactant having the previously described Formula I. The 
amount of each constituent is the same as that previously described in the 
preferred embodiment. Agitation is continued until a clear dispersion is 
produced. 
Advantages of the present invention are illustrated by the following 
specific examples. These examples are set forth for purpose of 
illustration and should not be construed as limiting the invention.

EXAMPLE I 
Clear stable gasoline-alcohol-water fuel Composition No. 1 was made by 
mixing together 50 parts by volume of clear unleaded gasoline (base fuel) 
and 50 parts by volume of clear gasoline with the addition of 4000 parts 
per million of water, 2.7 volume percent of methanol, and 6.3 volume 
percent of tertiary butyl alcohol to produce a hazy fuel composition. 
Surfactant compositions A to D (Formula I) as shown in Table I were then 
added dropwise at temperatures of 64.degree. F. and 40.degree. F. to said 
hazy fuel composition until the mixture was clear. The results of the fuel 
appearance are shown in Table II. 
TABLE I 
______________________________________ 
COMPOSITION OF FORMULA I SURFACTANTS 
Formula I 
Polyoxy- Polyoxy- Molecular 
Surfactants 
ethylene propylene a + c b Weight 
______________________________________ 
A 30 wt. % 70 wt. % 8.2 14.5 1200 
B 40 wt. % 60 wt. % 10.9 12.4 1200 
C 30 wt. % 70 wt. % 11.9 21.1 1750 
D 40 wt. % 60 wt. % 15.9 18.1 1750 
______________________________________ 
TABLE II 
______________________________________ 
FUEL APPEARANCE 
Amount of Surfactant to Produce 
Fuel Composition Clear Stable Fuel Composition 
Temp. .degree.F. 
No Surfactant 
C D B 
______________________________________ 
64.degree. 
Hazy 0.02 cc 0.03 cc 0.11 cc 
40.degree. 
Hazy 0.26 cc 0.07 cc 0.16 cc 
______________________________________ 
EXAMPLE II 
50 parts by volume of clear gasoline was mixed with 4000 parts per million 
of water, 2.7 volume % of methanol, and 6.3 volume % of tertiary butyl 
alcohol to produce Mixture 1. Clear unleaded base fuel e.g. gasoline 
called Mixture 2 was mixed with Mixture 1 in the volumetric proportions 
shown in Table II e.g. 10-50% Mixture 1 and the remainder Mixture 2 to 
produce a hazy Fuel Composition. Formula I surfactants A-D (see Table I in 
Example I) were added drop wise at 64.degree. F., 40.degree. F., and 
-4.degree. F. until after the addition of the specified cubic centimeters 
of surfactant the hazy fuel composition became clear and the subject clear 
stable fuel composition was produced. The results are shown in Table III 
below: 
TABLE III 
______________________________________ 
Amount of Surfactant to Produce 
Sur- Mixture Mixture Clear Stable Fuel Composition 
factant 
1 2 64.degree. F. 
40.degree. F. 
-4.degree. F. 
______________________________________ 
A 10% 90% 0.12 cc 
0.35 cc -- 
30% 70% 0.24 cc 
0.64 cc -- 
50% 50% 0.22 cc 
0.65 cc -- 
C 10% 90% .05 cc 
-- -- 
30% 70% 0.12 cc 
0.15 cc -- 
50% 50% 0.02 cc 
0.26 cc -- 
D 10% 90% 0.06 cc 
-- -- 
30% 70% 0.09 cc 
0.13 cc 0.16 cc 
50% 50% 0.03 cc 
0.07 cc 0.37 cc 
B 10% 90% 0.05 cc 
-- -- 
30% 70% 0.1 cc 
-- 0.15 cc 
50% 50% 0.11 cc 
0.16 cc 0.19 cc 
______________________________________ 
Although this invention has been illustrated by reference to specific 
embodiments, it will be apparent to those skilled in the art that various 
changes and modifications may be made which clearly fall within the scope 
of this invention.