Gasoline Fuel Containing Polyalkoxylated Alkylphenol To Reduce Exhaust Emission

Abstract

By using a fuel composition containing a small but effective amount of a polyalkoxylated alkylphenol of the general formula ##SPC1## Wherein: R.sub.1 = an alkyl of 4 to 12 carbon atoms n = an integer from 2 to 15 R.sub.2 = independently for each of the n units H or methyl The hydrocarbon emission in the exhaust from an internal combustion engine is reduced.

Description

BACKGROUND OF THE INVENTION

As greater concern for air pollution becomes manifest, the contribution of internal combustion engines, especially automobile engines, has come under closer scrutiny. To date, the greatest thrust of the fight against air pollution by internal combustion engines has been the physical alterations in the design of the engine to reduce the various pollutants emitted.

A new and properly tuned automobile engine has lowest hydrocarbon emission in the exhaust gas. Operation of the engine causes an accumulation of solid combustion products on the walls of the combustion chamber and an increase in the hydrocarbon emission in the exhaust gas. This build-up of deposits and increase in hydrocarbon emission reaches a plateau after a number of hours of operation and remains essentially constant for the duration of the engine life. Between the initial level of hydrocarbon emission and the plateau, the hydrocarbon content in the exhaust gas will normally increase approximately 80 percent.

The Dow Chemical Company's product bulletin on Ambifal 200 shows the use of Dowfax 9N5, the pentaethylene oxide adduct of nonylphenol, as a deicer in gasoline to be added only in the winter in amounts up to 200 p.p.m. by volume.

SUMMARY OF THE INVENTION

According to the present invention, the hydrocarbon content in the exhaust gas of an internal combustion engine is maintained at a relatively low level by using a fuel composition containing a small but effective amount of a polyalkoxylated alkylphenol having the general formula ##SPC2##

Wherein:

R.sub.1 =an alkyl of 4 to 12 carbon atoms

N=AN INTEGER FROM 2 TO 15

R.sub.2 =independently for each of the n units hydrogen or methyl.

By use of this fuel, the hydrocarbon emission is reduced without modification of the internal combustion engine.

The polyalkoxylated alkylphenol of the present invention may suitably be any of the compounds described by the general formula or mixtures thereof that are compatible with the fuel used in an internal combustion engine. Representative examples of these compounds suitably include pentaethoxylated butylphenol, octaethoxylated hexylphenol, diethoxylated nonylphenol, tetraethoxylated nonylphenol, nonaethoxylated nonylphenol, heptaethoxylated dodecylphenol, pentapropoxylated pentylphenol, heptapropoxylated nonylphenol, pentadecapropoxylated decylphenol, diethoxylated-tetrapropoxylated nonylphenol, tripropoxylated-pentaethoxylated decylphenol, and pentaethoxylated-dipropoxylated pentylphenol. Of the many suitable compounds of the general formula, those wherein R.sub.1 has 6 to 10 carbon atoms and wherein n is 2 to 10 are preferred. Especially preferred in the present invention are the nonylphenol derivatives, with the ethoxylated nonylphenol compounds containing 2 to 9 ethyleneoxy units being of special interest.

The compounds of the present invention may be prepared by conventional base-catalyzed oxyalkylation reaction and they are commercially available. Ordinarily, the formula given for the polyalkoxylated alkylphenol generally shows only the average number of alkyleneoxy units and the average length of the alkyl chain.

The fuels of the present invention may suitably be any of the conventional gasolines for internal combustion engines that are commercially available. The fuel may contain any amount of the polyalkoxylated alkylphenol that gives the desired reduction of the hydrocarbon content in the exhaust gas. Generally, a concentration greater than about 200 p.p.m. is required for a desirable effect. Suitably, the concentration of the polyalkoxylated alkylphenol may range from about 250 to about 4000 p.p.m. by weight with concentrations of about 250 to about 1,250 p.p.m. by weight being preferred.

The polyalkoxylated alkylphenols of the present invention are generally compatible with most fuels for an internal combustion engine even in substantial concentrations. However, in certain cases, the higher molecular weight compounds tend to become insoluble at low temperatures. To combat this insolubility, a suitable solvent such as an alcohol or ether may be employed in amounts sufficient to solubilize the additive in the fuel.

In addition to the improved hydrocarbon emission control, the fuels containing higher concentrations of the polyalkoxylated alkylphenol also reduce or even eliminate undesirable carbon and tar deposits on the intake valves, the exhaust valves, the respective valve seats and the carburetor. This is certainly a desirable characteristic since much of the engine maintenance cost is associated with sticking and improperly seated valves as well as fouled carburetors. Thus, by using the fuels of the present invention in an internal combustion engine, the hydrocarbon content in the exhaust is reduced while the valves and carburetor are kept relatively free of such deposits.

SPECIFIC EMBODIMENTS

Example 1

The effectiveness of the additives of the present invention was tested in a single cylinder four-cycle "Labeco" engine which is a Coordinating Lubricant Research engine adapted for fuel studies. The engine was operated at a constant speed of 1,750 r.p.m. with an air consumption of 65 pounds per hour and a fuel consumption of 5.4 pounds per hour. The torque in units per pound was OBS-40, the spark advance was 22.degree. B.T.C. and the intake manifold vacuum was 1.4 inch of mercury. The fuel used in this and all tests was Indoline 30, a standard research gasoline made by the Standard Oil Company. This fuel has 3 ml. of tetraethyl lead per gallon with 1/2 of the theoretical ethylene dibromide and 11/2 of the theoretical ethylene dichloride based on the tetraethyl lead as scavengers for the lead.

Each test was run for 100 hours and the engine was torn down and completely cleaned. The first run was made without an additive and the second run used the same fuel containing 250 p.p.m. by weight of nonaethoxylated nonylphenol, Dowfax 9N9. The exhaust gas analysis was made by Beckman Model 109A hydrocarbon analyzer and the results are shown in p.p.m. by weight.

The standard test run without the additive showed an initial hydrocarbon emission of 270 p.p.m. with a sharp increase to 410 p.p.m. at 20 hours of operation and then a gradual increase in the hydrocarbon emission to 480 p.p.m. at 100 hours of operation. The test run with 250 p.p.m. by weight of the Dowfax 9N9 had an initial hydrocarbon emission of 280 parts per million with a gradual increase to 340 parts per million after 100 hours of operation.

Example 2

a series of tests was run on a Ford six cylinder 240 cu. in. industrial engine model C5PF with the fuel shown in example 1. The engine was operated at 1615 r.p.m. during the analysis of the hydrocarbon emission. After each test, the engine head was removed and all deposits were removed from the combustion chamber. Three standard control tests using Indoline 30 were run immediately prior to the additive tests using the fuel containing nonaethoxylated nonylphenol, Dowfax 9N9. The data for the average of the standard tests in addition to comparative tests on three additive runs are given in table I. ##SPC3##

Example 3

Using the engine and procedures of example 2, the effectiveness of Indoline 30 containing various amounts of tetraethoxylated nonylphenol, Dowfax 9N4, in reducing the hydrocarbon emission in the exhaust was determined. Three test runs were made on the fuels of the invention, with one standard test being made before and one standard test being made after the three test runs. Data for the standard tests and three additive tests are shown in table II. ##SPC4##

Example 4

The weight of the deposits from the intake and exhaust valves was recorded for each of 100 hour runs in example 2 and 3. For the nonadditive runs, the average weight of the deposits on the intake valve was 3.5 grams after 100 hours of operation. For the same period of operation using 4,000 p.p.m. of Dowfax 9N4, no deposits on the intake valve were found and with fuels containing Dowfax 9N9 in amounts of 1,000 and 4,000 p.p.m. the weight of the deposits on the intake valve were 0.6 and 0.0 grams respectively.

The weight of the deposits on the exhaust valve averaged over the five nonadditive runs was 3.8 grams. In contrast to this, the deposits on the exhaust valve when 250, 1,000 and 4,000 p.p.m. of the Dowfax 9N4 were added to the fuel weighed 2.6, 3.8 and 0.6 grams respectively, while for the same concentrations of Dowfax 9N9 2.9, 3.2 and 2.1 grams of deposits were respectively obtained.

In the same manner as described in the above examples, other additives of the present invention may be used in the fuel described in the examples or other commercially available fuels. For example, 1,000 p.p.m. of diethoxylated nonylphenol, dodecaethoxylated butylphenol, tetrapropoxylated hexylphenol, decapropoxylated nonylphenol, diethoxylated-pentapropoxylated nonylphenol and tripropoxylated-heptaethoxylated octylphenol may be added to Indoline 30 with similar reduction of the hydrocarbon emission in the exhaust gas.

Claims

I claim:

1. A gasoline fuel composition for internal combustion engines containing greater than about 200 p.p.m. of a polyalkoxylated alkylphenol of the general formula ##SPC5##

wherein

R.sub.1 = an alkyl of 4 to 12 carbon atoms

n = an integer from 2 to 15

R.sub.2 = independently for each of the n units H or methyl.

2. The fuel composition of claim 1 wherein R.sub.1 has 6 to 10 carbon atoms and wherein n is 2 to 10.

3. The fuel composition of claim 1 wherein the polyalkoxylated alkylphenol is a polyalkoxylated nonylphenol.

4. The fuel composition of claim 3 wherein the polyalkoxylated nonylphenol contains 2 to 9 ethyleneoxy units.

5. The fuel composition of claim 1 wherein the concentration of the polyalkoxylated alkylphenol is 250 to 4,000 p.p.m. by volume.

6. The fuel composition of claim 5 wherein the concentration is 250 to 1,250 p.p.m.

7. A method of reducing the amount of hydrocarbon emitted in the exhaust of an internal combustion engine comprising using the fuel composition of claim 1 in the engine.