US3056667A - Leaded gasoline containing phosphorus and phosphate - Google Patents

Description

ENG/NE POWER L0$$- PERCENT Oct. 2, 1962 R. B. PAYNE ETAL LEADED GASOLINE CONTAINING PHOSPHORUS AND PHOSPHATE Filed Sept. 2, 1959 SPARK PLUG FOUL/N6 i I O BASE LEADED GASOLINE l8 BASE LEADED GASOLINE 0.3 T YELLow PHOSPHORUS BASE LEADED GA$0L/NE* 0.225T YELLOW PHO$PHOPUS+ x 0.075T METHYL PHOSPHATE a! i it 6 u 5i ENG/NE TEST HOURS d BASE LEADED GASOLINE BASE LEADED GASOLINE+ 0.3T METHYL PHOSPHATE BASE LEADED GASOLINE-I- 0.3T YELLow PHOSPHORUS BASE LEADED GASOLINE- Q/ST YELLow PHOSPHORUS +0./5T METHYL PHOSPHATE L l: a is /'0 IE #4 OCTANE REQUIRMENT INCREASE AFTER 2/0 HOURS INVENTORS RICHARD B. PAYNE ADOLH-l L MRS T /K EVERETT IV. CASE ATTORNEYS 3 056 667 LEADED GASOLINE CGIJTAINING PHOSPHORUS AND PHOSPHATE Richard B. Payne, Park Forest, and Adolph V. Mrstik and Everett N. Case, Homewcod, Ill., assignors, by mesne assignments, to Sinclair Research, Inc, New York,

NE? a corporation of Delaware Filed Sept. 2, 1959, Ser. No. 837,647 5 Claims. (CI. 44-69) This invention relates to improved gasoline which is of high octane number and which has incorporated therein a lead compound as an anti-knocking agent and an additive combination of yellow phosphorus and a selected methyl phosphate.

In using a gasoline in a spark-ignition internal combustion engine, various problems arise. One of these is ordinary knocking which is combatted by increasing the octane rating of the fuel. By and large, modern gasolines have an octane number of at least 85 RON, that is, as determined by the Research Method. Almost without exception producers of gasoline use non-hydrocarbon agents to raise the octane number of the gasoline. Generally, this agent is a tetraalkyl lead, especially tetraethyl lead, usually within the range from about 0.5 to 3.0 cc. per gallon, or even as much as approximately 4.5 cc. per gallon, as a knock-suppressing agent. Tetraethyl lead is the most widely used anti-knock agent, and is very effective for this purpose: it can raise the octane rating in a gasoline and when this octane is raised enough, ordinary engine knock is overcome. However, the use of leaded gasoline leads to other problems, among which are pre-ignition, spark plug fouling and octane requirement increase.

Pre-ignition is apparently caused by the presence within the engine cylinder of lead-containing deposits. These deposits are hot and cause the mixture in the cylinder to burn before combustion is initiated at the proper time by the spark plug. Pre-ignition can be controlled, as the art is aware, by the addition of phosphorus additives to leaded gasoline. Pre-ignition is evidenced by a ping.

Spark plug fouling is also attributed to lead deposits which seem to cause short circuiting of the spark current in the cylinder, leaving the fuel in some cylinders unignited. A good deal of power loss is attributed to spark plug fouling. If this problem is caused by lead deposits, the troublesome deposits are probably different from those which cause pre-ignition since additives useful in controlling pre-ignition vary widely in their effectiveness on spark plug fouling. Another problem encountered with the use of leaded gasoline is octane requirement increase (ORI). Ordinary leaded gasoline causes the engine to need higher and higher octane gasoline in order to prevent ordinary engine knock. This phenomenon is wellknown in the art but not many remedies are known.

This invention is directed to a high octane leaded gasoline, i.e. gasoline containing a soluble lead compound such as a tetra lower alkyl lead compound, having incorporated therein yellow phosphorus and a methyl phosphate of the type R Where R is phenyl including phenyl groups substituted on the ring with up to two lower alkyl (1 to 4 carbon atoms) groups and R is R or methyl or a mixture of the two. The resulting fuel solves the pre-ignition problem, minimizes spark plug fouling and inhibits octane requirement increase. The results obtained from incorporating both elemental phosphorus and the methyl phosphate are better than merely the cumulative effects from their separate incorporation. The yellow phosphorus and the selected methyl phosphate are incorporated into the gasoline genie rates 3,056,667 Patented Oct. 2, 1962 erally in a total amount of from about 0.05 to 2 theory, and preferably in the amount of from about 0.1 to 0.6 theory, 1.0 theory meaning that for each three gram atoms of lead present in the tetraalkyl lead there are incorporated two gram atoms of phosphorus. 'One theory is based upon the premise that the phosphorus and the lead in the tetraalkyl lead react in the combustion zone to form lead orthophosphate, Pb (PO Stated somewhat difierently, for each three gram moles of tetraethyl lead present in the gasoline, there is also generally incorporated from about 0.1 to 4 gram atoms of phosphorus and preferably from about 0.2 to 1.2 gram atoms of phosphorus. The yellow phosphorus is usually incorporated in an amount of about 30 to 85 theory percent of the total phosphorus, preferably about 40 to 80%: for example, where the phosphorus totals about 0.3 theories, the gasoline will have incorporated about 0.09 to 0.25 theories of yellow phosphorus and about 0.05 to 0.21 theories of methyl phosphate.

Suitable methyl phosphate materials for incorporation in the composition of the invention are commercially available under the trade names ICC No. 2. and ICC No. 3. The first-named material is a mixture containing predominantly dimethyl xylyl phosphate, the balance consisting essentially of methyl dixylyl phosphate along with traces of trimethyl phosphate and trixylyl phosphate. ICC No. 3 is predominantly diphenyl methyl phosphate with the balance made up of phenyl dimethyl phosphate, triphenyl phosphate and trimethyl phosphate. The preferred lead compound is a tetra lower alkyl lead, such as tetraethyl lead.

In obtaining the novel composition of the invention the yeliow phosphorus and the phosphate may be incorporated separately or as a mixture into'a blend containing all of the gasoline hydrocarbons. Alternatively, each of the phosphorus materials or a mixture of them may be first incorporated into any one or any combination of the hydrocarbon components before final blending, as all that is required to accomplish the desired result is the incorporation of the phosphorus and phosphate in the leaded gasoline by any convenient route. The following examples of the composition of the invention are intended to be illustrative only and not limiting.

Base gasoline A contained, by volume, 28.4% heavy naphtha reformate, 28.4% light fluid catalytically cracked gasoline, 19.0% mixed xylenes, 19.0% alkylate and 5.2% butane. It had an API gravity of 51.5, an octane number of 104.3 by the Research Method and an octane number of 93.2 by the Motor Method. The ASTM distillation of gasoline A was as follows, in degrees F.:

Initial boiling point 99 10 percent 136 50 percent 260 r 90 percent--- 329 End point 388 Base gasoline B contained the same constituents as base gasoline A, except that the heavy naphtha reformate came from a different source. It had the following characteristics:

Base gasoline C was composed by volume of 20% isobutane-butane alkylate, 53% heavy naptha reformate, 22% light fiuid catalytically cracked gasoline and 5% assess? butane. Gasoline C had an API gravity of 53.6, an octane number by the Research Method of 101.7 and an octane number by the Motor Method of 91.8. The ASTM boiling range of the base gasoline C was as follows:

F. Initial boiling point 90 percent 118 50 percent 264 90 percent 319 End point 381 Each of these base gasolines contained 3 cc. per gallon of tetraethyl lead, which had been added as Motor Mix, a commercially available tetraethyl lead containing a fixed amount of a halo-hydrocarbon scavenger.

Into a portion of each base gasoline there were dissolved various additives in the amount of 0.3 theory to give the following test fuels:

Samples I, II and III were used in a test for spark plug fouling by using them in a 1956 Buick test engine. The engine was cycled automatically between idle and low speed, road load operation. Every 24 hours a determination of the braking horsepower of the engine was made at 3000 r.p.m. and wide open throttle, the test spark plugs replaced with a set of new plugs, the braking horse- The test on Sample I which contained no phosphorus additive was discontinued at 146 hours and a 21% power loss was detected as due to spark plug fouling. Sample II, in which yellow phosphorus was incorporated, was tested for 195 hours with a 14% power loss. The test on Sample III incorporating both yellow phosphorus and a predominantly dimethyl xylyl phosphate mixture gave only slight indication of spark plug fouling and was halted at 322 hours.

These figures show that although a leaded fuel having yellow phosphorus incorporated therein gives less spark plug fouling from that encountered when only the base leaded gasoline is used, its incorporation along with a methyl phosphate even in a very minor amount reduces power loss due to spark plug fouling by a large percentage, which is disproportionate to the quantity used.

Samples IV to VIII were used to test for octane requirement increase in a 210 hour accelerated manual cycling dynamometer test run on a 1957 Cadillac engine. The engine was cycled manually over a range of speeds and road loads, including idle. The octane requirement was determined every 42 hours at 1500 r.p.m. full load and 2500 r.p.m. full load until an equilibrium was reached where no further increase occurred.

A test on a sample of base gasoline B containing no phosphorus additive showed an octane requirement increase, after 210 hours, of 11.3, while Sample IV after 210 hours at 1500 r.p.m. showed an octane requirement increase of only 10.0. The results of tests on the other samples are shown in Table III. The resultant difference between the clean engine requirement and the equilibrium requirements at each speed are averaged to give Aver- Table III.Dynam0meter 0R1 Test Data1957 Cadillac Engine ENGINE OC'IANE NUMBER REQUIREMENT Sample V Sample VI Sample VII Sample VIII Test Hours 1, 500 2, 500 1, 500 2, 500 1, 500 2, 500 1, 500 2, 500 r.p.m r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m.

power again determined at 3000 r.p.m. and wide open throttle and the test plugs reinstalled. The decrease in braking horsepower caused by spark plug fouling is reported in Table II and FIGURE 1 of the drawings for each of these three sample gasolines.

Table II.-Percent Decrease in Brake Horsepower Due to Spark Plug Fouling 1956 BUICK3000 R.P.M.WIDE OPEN THROTTLE Test Hours Sample I Sample II Sample III P 99 5 moocsamme age ORI figures reported in Table III and FIGURE 2 of the drawing.

These figures show the effectiveness of the yellow phosphorus and methyl phosphate incorporation in inhibiting octane requirement increase. Where Sample VI, having incorporated therein no elemental phosphorus, was tested the octane requirement was found to increase even more than when the base leaded gasoline was used. Where a dimethyl xylyl phosphate mixture or a diphenyl methyl phosphate mixture and yellow phosphorus were incorporated, the octane requirement increased less than when the base fuel alone was used, and increased only slightly more than when yellow phosphorus was incorporated alone in a base leaded gasoline. It will also be noted that the octane requirement increase found when using a composition made according to this invention (Sample VIII) is not the average of Samples VI and VII.

At the end of each of these tests pre-ignition determinations were obtained by running the engine at 1500 r.p.m. and wide-open throttle with a reference fuel. Table IV gives the highest octane number reference gasoline to give after-fire when the ignition is turned off at 1500 r.p.m. full load. A fuel slightly higher in octane number is therefore required in each case to suppress preignition.

Table IV After running engine on Test No. Octane These results show that the composition of this invention is effective in reducing pre-ignition as well as the other major problems faced by the automobile owner who uses leaded gasoline.

This is a continuation-in-part of our application Serial No. 788,414, filed January 22, 1959.

We claim:

1. A leaded gasoline composition consisting essentially of gasoline, about 0.5 to 4.5 cc. per gallon of tetra lower alkyl lead anti-knock agent and having incorporated therein yellow phosphorus and a methyl phosphate of the formula where R is selected from phenyl and phenyl with up to 6 two lower alkyl substituents and R is selected from R and methyl in a total of about 0.05 to 2 theories with the yellow phosphorus being about 30 to theory percent of the total phosphorus.

2. The gasoline composition of claim 1 wherein the tet-raalkyl lead compound is tetraethyl lead.

3. The gasoline composition of claim 2 where the gasoline has about 0.1 to 0.6 theory of yellow phosphorus and the methyl phosphate incorporated therein.

4. The gasoline composition of claim 1 where the methyl phosphate is a methyl Xylyl phosphate.

5. The gasoline composition of claim 1 where the methyl phosphate is a methyl phenyl phosphate.

References Cited in the file of this patent UNITED STATES PATENTS 1,913,970 Albers June 13, 1933 2,889,212 Yust et al. lune 2, 1959 2,892,691 Howell June 30, 1959 2,897,068 Pellegrini et al July 28, 1959 2,911,431 Orlofl et al. Nov. 3, 1959 FOREIGN PATENTS 27,733 Great Britain Dec. 2, 1913 683,405 Great Britain Nov. 26, 1952 709,653 Great Britain June 2, 1954 1,134,156 France Nov. 26, 1956

Claims (1)

1. A LEADED GASOLINE COMPOSITION CONSISTING ESSENTIALLY OF GASOLINE, ABOUT 0.5 TO 4.5 CC. PER GALLON OF TETRA LOWER ALKYL LEAD ANTI-KNOCK AGENT AND HAVING INCORPORATED THEREIN YELLOW PHOSPHORUS AND A METHYL PHOSPHATE OF THE FORMULA

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