US2985578A - Improved gasoline fuel components - Google Patents

Description

United States Patent IIVIPROVED GASOLINE FUEL COMPONENTS Fredrick L. Jonach, Kew Gardens, N.Y., assignor to Esso Research and Engineering Company, a corporation of Delaware Filed Jan. 2, 1958, Ser. No. 706,564

8 Claims. (Cl. 208-16) No Drawing.

The present invention concerns the treatment of naphtha fractions that are ordinarily not suitable as components of gasolines for modern automotive engines to render them acceptable for that use. The invention is particularly directed to a process for improving the engine cleanliness characteristics of such naphtha fractions when they are used in motor gasolines as well as to the improved naphtha fractions themselves.

lead and tetra ethyl lead are valuable gasoline constit-v uents in that they reduce engine knocking that is attributable to compression ignition phenomena, they are at the same time detrimental in that they cause the formation of engine deposits which in the long run will increase the octane level requirements and give unsatisfactory engine operation. These deposits become incandescent during engine operation and ignite the mixture of fuel and air prematurely by a phenomenon commonly referred to as surface ignition. The deposits also build up on the points and insulators of spark plugs and thus cause spark plug misfiring. Such deposit buildups are customarily avoided or minimized by employing scavenger agents. The most commonly used agents are ethylene dichloride and ethylene dibromide which, during combustion, furnish halogen acids that combine with the lead and convert it to a relatively volatile lead halide which is removed with the gasoline engine exhaust gases. 'Ihese scavenger agents are not entirely satisfactory, however, and deposit formation and the resulting difficulties occur in modern high compression engines in spite of the use of these scavenger agents.

It has been found more recently that organic compounds of phosphorus are desirable additives for inclusion in leaded gasolines in that they are effective for overcoming the difliculties that are associated with the use of conventional lead scavenging agents. It is'one function of the present invention to introduce minor proportions of phosphorus compounds into the motor fuel for the purpose stated. It is another function of this invention to convert cracked naphtha fractions that are normally unsuitable as gasoline components into fractions than can be used to advantage in gasoline compositions.

In accordance with the present invention petroleum.

cracked naphthas, particularly the higher boiling fractions of heavy thermal reformates, are treated with the reaction products of phosphorus sulfides and olefin polymers, thereby removing from those fractions the impurities that normally cause engine fouling when gasolines containing the cracked naphthas are used in an internal combustion engine. At the same time the treat- 2,985,578 Patented .May 23, 1961 "ice ment of the cracked naphtha fractions in this manner about 1,000 to 5,000 molecular weight.

pounds that are useful in assisting in the scavenging of lead from leaded gasolines burned in the engines.

The reaction products employed in the present invention for treating the cracked naphtha fractions are obtained by reaction of a sulfide of phosphorus, preferably P S with a C to C olefin polymer, i.e., of ethylene, propylene, butylene or isobutylene, of from about 250 to about 10,000 molecular weight, and preferably Isobutylene polymers are preferred. The reaction product is readily obtained by a reaction of the phosphorus sulfide with the olefin polymer at a temperature of about 200 to 600 F. and preferably from about 300 to about 500 F. Preferably, from about 2 to about 5 molecular proportions of the olefin polymer are employed for each molecular proportion of the phosphorus sulfide in the reaction. It is ordinarily desirable to employ an amount of the phosphorus sulfide that will react completely with the olefin polymer. The reaction is continued until substantially all of the phosphorus sulfide has been reacted.

The phosphorus sulfide-olefin polymer reaction product is then employed to treat a cracked naphtha fraction. The amount of phosphorus sulfide reaction product used will be in the range of from about V of the weight of the naphtha fraction treated to about an equal weight based on the naphtha fraction and preferably about ,4 to /s of the weight of the latter. Treating temperatures will range from about to about 350 F. and preferably from about 180 to about 250 F. The reaction is continued for a period of from /2 to 10 hours and the reaction product is then distilled to recover the treated naphtha as the distillation product. Although almost any normally undesirable cracked gasoline fraction may be treated by the process of the present invention, it is particularly adaptable to the treatment of heavy reformate fractions, from the well known petroleum refining processes of reforming and hydroforming, and especially to the treatment of what are known as heavy thermal reformate fractions, i.e., the fractions boiling above 200 F. and below 550 F., e.g., between 250 F. and 450 F.-

The following examples are illustrative of the invention.

EXAMPLE 1 A quantity of isobutylene polymer of 1100 Staudinger,

molecular weight was heated with 10 percent by Weight of P 5 at about 425 F. for about four hours. The material was then diluted with a quantity of a light hydrocarbon oil to about 60 percent concentration for ease in filtration and further handling. The filtered concentrate analyzed 2.63 percent sulfur and 1.42 percent phosphorus.

EXAMPLE 2 head temperature of 292 F. at 150 mm. Hg and then The treated reformate was recovered asthe distillate. The optical density of the recovered product was measured as an indication to 270 F. at 10 mm. Hg pressure.

of the improvement obtained by the treatment. The results are given in Table I for the materials untreated or raw, and washed with a 20% aqueous solution of caustic soda, i.e., NaOH Washed.

Optical density is measured in terms of the logarithm of (IOU/percent light transmitted). It is well known in the art that the engine cleanliness characteristics of cracked orreformed petroleum naphthas can be evaluated by a comparison of the optical densities of the naphthas after treatment with suitable reagents such as fluoboric acid, sulfuric acid etc. The values of optical density in Table I above and Table III'below were obtained by measuring light transmission in a Lumetron colorimeter after the samples of naphtha had been treated as follows: Treat 1 cc. of sample with cc. of reagent consisting of 10 parts of dilute sulfuric acid and 90 parts of acetic acid; then dilute to 100 cc. with acetic acid, and measure optical density.

By actual tests of various gasolines in a Chevrolet engine, it was established that the optical density measured the relative quantities of deposits in the engine as shown in Table II wherein the sludge rating of 100 was obtained on a commercial motor gasoline of regular grade and average cleanliness quality.

1 Test procedure Eli-4'45 described by l). '1. Rogers, W. W. Rice and F. L. Jonach before meeting of Society of Automotive Engineers, November 10, 1955. Test consumes 6 hours in 3 cycles of about 2 hours each'at' 40 B.H.P. output. First cycle 500 r.p.m., water jacket and oiltemperatures 115 F.; second cycle 2000 r.p.m., Water jacket temperature 160 F.,

oil temperature 175 F.; third cycle 2000 r.p.n1., water jacket temperature 160 F., oil temperature 225 F. Total test duration, 110 hrs.

EXAMPLE 3 In the same manner as in Example 2, various fractions.

of the thermal reformate were individually treated with the reaction product of Example 1. The optical density measurements of the treated products and the optical densities of the corresponding untreated cuts are given in Table III. The data in Tables I and III indicate that the various: thermal reformate cuts were considerably improved by the process of the present invention.

Table III (Optical Density) X100 Untreated Treated Thermal Reiormate Cut 1 .Q.- 66. 8 1. 4 Thermal Reformate Cut 92.1 2. 8 Thermal Reformate Cut a 188. 6 6. 9

1 Boiling range 400416 F. Boiling range Ado-427 F. 3 Boiling range 427 F.+

' to 10 hours with from% its weight toan equal weight 4 Each of the treated fractions was found on analysis to contain phosphorus as shown in Table IV.

For lead scavenging purposes, the phosphorus content of gasoline is controlled between 0.05 and 1.0 theory, or stoichiometric proportion, of the lead. If 3 cc. of tetraethyl lead, i.e., 5 grams, is added to one gallon of gasoline, which weighs 3000 grams, the lead content of the gasoline will be about 0.1 percent, since the lead content of tetraethyl lead is 64 percent. One theory of phosphorus is equal to about 10 percent of the Weight of lead. One theory of phosphorus in a gasoline containing 0.1 percent lead would amount to about 0.01% by weight of the gasoline. Thus, the treated reformate analyzing 0.0005% phosphorus contained 0.05 theory of phosphorus when the reformate wasleaded with 3' cc.

' of tetraethyl lead per gallon.

This invention is not to be limited to the specific examples herein presented for the purpose of illustrating the invention as modifications thereof within the skill of the art are contemplated. The scope of the invention is limited only by the claims appended hereto.

What is claimed is: L

1. An improved cracked naphtha component for a gasoline composition to which an alkyl lead antiknock agent is to be added, which improved naphtha component is obtained by treating a cracked naphtha fraction, containing materials that normally tend to cause engine fouling when employed as a component ofan internal combustion engine fuel, at from to 350 F; for from to 10 hours with from itsweight to an equal weight of the reaction product of. a sulfide of phosphoruswith a C to C olefin polymer of from. 250'to 10,000'

in said cracked naphtha fraction comprises a thermal reformate fraction boiling inthe range-of 2.0.0 to 550 F.

4. A naphtha component'as defined by claim 1 wherein said reaction with said sulfide of phosphorus is,conducted at temperaturesin the rangeH'of about. 200 to 5. The method of improving a cracked, naphtha frac-- tion containing materials that. normallyftendtocause engine fouling when said' crackednaphtha fraction; is. employed as a component of an, internal combustion.

engine fuel, which method comprises treating said naphtha fraction at from, 150 to 350 for from of the reaction product ofa sulfide of phosphorus with a C to C olefin polymer of from 250 :to 10,000zmolecular weight, distillingv the naphtha materialthus obtained and recovering the treated naphtha fraction; as adistill ate;

6. A method as defined in. claim; 5v wherein. said .re-

action of. said.sulfidesofiphosphorus with;:said:.olefin. poly- References Cited in the file of this patent UNITED STATES PATENTS Hill et a1 July 5, 1955 Bartleson June 4, 1957 Bartleson June 4, 1957 Brehm et a1. July 28, 1959

Claims (1)

1. AN IMPROVED CRACKED NAPHTHA COMPONENT FOR A GASOLINE COMPOSITION TO WHICH AN ALKYL LEAD ANTIKNOCK AGENT IS TO BE ADDED, WHICH IMPROVED NAPHTHA COMPONENT IS OBTAINED BY TREATING A CRACKED NAPHTHA FRACTION, CONTAINING MATERIALS THAT NORMALLY TEND TO CAUSE ENGINE FOULING WHEN EMPLOYED AS A COMPONENT OF AN INTERNAL COMBUSTION ENGINE FUEL, AT FROM 150 TO 350*F. FOR FROM 1/2 TO 10 HOURS WITH FROM 1/50 ITS WEIGHT TO AN EQUAL WEIGHT OF THE REACTION PRODUCT OF A SULFIDE OF PHOSPHORUS WITH A C2 TO C4 OLEFIN POLYMER OF FROM 250 TO 10,000 MOLECULAR WEIGHT, DISTILLING THE NAPHTHA MATERIAL THUS OBTAINED, AND RECOVERING THE TREATED IMPROVED NAPHTHA FRACTION AS THE NAPHTHA DISTILLATE.