US2881202A

US2881202A - Gasoline ignition control additives

Info

Publication number: US2881202A
Application number: US539259A
Authority: US
Inventors: John A Pianfetti; Gennady M Kosolapoff
Original assignee: FMC Corp
Current assignee: FMC Corp
Priority date: 1955-10-07
Filing date: 1955-10-07
Publication date: 1959-04-07
Anticipated expiration: 1976-04-07

Description

GASOLINE IGNITION CONTROL ADDITIVES John A. Pianfetti, South Charleston, W. Va., and Gennady M. Kosolapotf, Auburn, Ala., assignors to Food Machinery and Chemical Corporation, New York, N.Y., a corporation of Delaware No Drawing. Application October 7, 1955 Serial No. 539,259

6 Claims. (Cl. 260-461) This invention relates to new compositions of matter, their novel preparation and their use as gasoline igni- F tion control additives.

More particularly, this invention relates to organophosphor'o'us compounds as new compositions of matter, their l novel preparation and their use as gasoline ignition control additives. l The need for improved gasolines has been spurred since the end of World War II by the automotive industrys race to produce more and more powerful internal combustion engines. To achieve this greater horsepower, engine man ufacturers have steadily increased cylinder compression ratios to the point where they now average 7.5 to 1. One of the factors necessary to achieve maximum operating efiiciency from these high compression engines is that the ignition of the fuel-air mixture takes place at the moment of greatest compression.

As engines become more powerful, they demand higher octane fuel which can be manufactured only with an increase in the tetra-alkyl lead content. The use of these organic lead compounds in gasolines leads to the formation, during combustion, of lead salts which catalyze the oxidation of the carbonaceous residues from the fuel and oil and lower the ignition temperature of the carbon residues thus creating glowing particles that ignite the fuelair charge prematurely.

It has been the practice of the art to add to fuels containing organic lead compounds, a halohydrocarbon for the purpose of converting the lead into lead halides volatile at the combustion temperature of the gas within the cylinder and which lead compound would be swept out with the exhaust gases.v These compounds are known as scavengers. In actual practice, however, the formation of lead oxyhalides and lead oxides as well as the volatile lead halides cannot be avoided and deposits of lead compounds are found in the combustion chamber even when such scavengers are employed.

It is an object of the instant invention to provide new compositions of matter which may be employed as gasoline additives. It is another object of this invention to provide new compositions ofmatter which will aid in the suppression of the pre-ignition characteristics of the fuelai'r mixture. It is a further object of this invention to provide novel means for preparing these new compositions of matter. Further objects will appear as a description l of this invention unfolds.

We have discovered certain organophosphorous compounds having properties which render them suitable for use as pre-ignition control additives. It has been found that the defect of pre-ignition arising from the use of conventional leaded gasolines can be substantially lessened by the use of the compounds of this invention. These organophosphorous compounds appear to function by conve'rting the lead present in the fuel into'lead compounds having a very low catalytic. eifect in reducing the ignition temperature of thecarbon deposits within the combustion chamber as compared to, the lead compounds .that form in.-

the 'bombus'tion chamber, absent the 'organophos'phorouk Patented Apr. 7, 1959 2 compounds of this invention. Thus, an increase in the ignition temperature of the cylinder deposit would likewise decrease the tendency of the deposit to pro-ignite the fuel-air mixture.

The terms, ignition temperature and glow point, are meant to be synonymous for the purposes of this specification unless a contrary intention is shown.

The organophosphorous compounds which we have discovered as suitable for use in accordance with this invention are: a

(1) Halogenated esters of phosphonous acid in which R may be a hydrogen, an aliphatic chain up to and including six carbon members, a phenyl or substituted phenyl radical, X may be a member of the halogen group and Y may be an aliphatic chain up to and including six carbon members, an aryl or a substituted aryl radical.

(2) Halogenated thio esters of primary phosphonic acids H I RCH-CHaOPOCHz-CHR in which R may be a hydrogen, an aliphatic chain up to and including six carbon members, a phenyl or substituted phenyl radical, X may be a member of the halogen group and Y may be an aliphatic chain up to and including six, carbon members, an aryl or a substituted aryl radical.

These new compounds, both the halogenated esters of phosphonous acid and the halogenated thio esters of phosphonic acid, were prepared in a novel manner.

. The novel manner of preparing the halogenated esters of phosphonous acid is through the reaction of dihalophosphines and oxiranes or substituted oxiranes.

The term oxirane is used to designate the grouping,

hence,

CHsCH-CH2 is known as methyl oxirane. This compound is also I known as propylene oxide.

The aliphatic and aromatic dihalophosphines may be prepared by heating phosphorus trihalide with the corre: sponding dialkylmercury or diarylmercury derivatives in sealed tubes for several hours at to 230 C., as described in the literature. p

The examples that follow illustrate the novel prepara- I tion of the haloesters of phosphonous acid.

EXAMPLE 1 and a calibrated addition funnel.

The flask was charged with 179 parts of phenyl dichloro phosphine. From the calibrated addition funnel was added 116 parts of methyl oxirane (propylene oxide).

The oxirane was added over a period of an hour while. maintaining the temperature of the reaction mass at about,

25 C. Upon completing the addition of the oxirane, the pressure in the system was reduced for a short-: interval .1 me tqzm t Ha d .to ea r m -Pi unreacted oxirane.

The product, bis(chloropropyl) phenyl phosphonite, obtained in near quantitative yield had a specific gravity of 1.180 35/4 and a refractive index of 1.5308, D/25.

Calculated for C H O PCI P=10.5%, Cl=24.1%. Found: P=.2%', Cl=23.4%

EXAMPLE 2 The apparatus used for this experiment was the same aszdescriibedin Example 1..

The flask was charged with. 117" parts of methyl dichlorophosphinet. From: the calibrated additionfunnel was added: l=16 parts of methyl oxirane propylene oxide).

The: oxirane: was: added. over a period of an hour while maintaining the temperature of the reaction mass at about 25 C. Upon completing the addition of the oxirane, the pressure in the system was reduced for a short interval of time to 2 mm. Hg in order to remove any traces of unreacted oxirane.

The product, bis(chloropropyl) methyl phosphonite, obtained in near quantitative yield, had a specific gravity of 1.137 35/4 C. and a refractive index of 1.4638 D/25 C.

Calculated for C H O PCl P=13.3%-, Cl=30.4%. Found: P=12.9%, Cl=29.6%.

The novel method of preparing the halogenated thionoesters of primary phosphonic acids is by the reaction of the halogenated esters of. phosphonous acid and. sulphur toyield the appropriate thionophosphonate.

The examples that follow illustrate the novel preparation of the halogenated thionoesters of phosphonic acid.

EXAMPLE 3 The apparatus used for this experiment was a 3-necked flask fitted with a stirrer, thermowell and a reflux condenser.

The flask was charged with 132 parts of bis(chloropropyl)- phenyl phosphonite. After heating the phosphonite to about 80 C., 15 parts of sulphur were added slowly over a 30 minute period while keeping the temperature at about 80 C. This temperature was maintained until but a trace of sulphur remained. The product was cooled, and filtered. The product, bis(chloropropyl) phenyl thionophosphonate obtained in near quantitative yield, had a specific gravity of 1.237 35/4 C. and a refractive index of 1.5451 D/25 C.

Calculated for C H O PSCl P=9.5%, Cl=21.7%, S=9.8%. Found: P=9.1%, Cl=21.5%, S=9.8%.

EXAMPLE 4 The apparatus used for this experiment was the same as described in Example 3.

The flask was charged with 105 parts of bis(chloropropyl) methyl phosphonite. After heating the phosphonite to about 80 C., 15 parts of sulphur were added slowly over a 30 minute period while keeping the temperature at about 80 C. This temperature was maintained until all but a trace of sulphur remained. The product was cooled, and filtered.

The product, bis(chloropropyl) methyl thionophosphonate, obtained in near quantitative yield had a specific gravity of 1.220 35/4 C. and a refractive index of 1.4933 D/25" C.

Calculated for C7H15OgPSC12: P=1l.7%, Cl=26.8%, S=12.1%. Found: P=11.3%, Cl=26.5%, S=12.1%.

The reaction between the dihalophosphine and oxirane may be conducted at temperatures below the preferred temperature of 40 C. The maximum temperature of reaction is that at which rearrangement of product occurs.

The reaction between the dihalophosphine and oxirane may be run at subor super-atmospheric pressure but for convenience it is preferable to operate at atmospheric pressure.

An inert gas, such as, carbon dioxide or nitrogen, may

b the Sy em, d ring the though it is not necessary to the practice of this invention that an inert atmosphere be maintained during the reaction of the dihalophosphine and oxirane.

The conversion of the haloester of phosphonous acid to the halogenated thio ester of a primary phosphonic acid by the addition of sulphur to the former may be run over a wide temperature range though it is preferable to maintain the reaction temperature at about C.

Preliminary testing of these compounds as pre-ignition additives involved the common gasoline. acceptance tests including: solubility of compound in gasoline, water tolerance, gum formation and copper corrosion- The first test, gasoline solubility, was conducted to determine at least qualitatively whether the organophosphorus compounds were soluble in gasoline. This determination was made by measuring the light transmittancy of the gasoline both with and without the addition of the organophosphorus compound.

Solutions which contained 0.03 volume percent of the phosphorus compounds were prepared by adding 0.03 ml. of the compound to ml. of a premium gasoline. After a short. shaking and standing period the solution was transferred to an optical cell and the light transmittance of the solution measured. This value was compared to the value for the premium gasoline which did not contain an additive. A decrease in the light transmittance of the base fuel of 1% or more indicates that the additive is sufliciently soluble for the purposes of this: invention.

The water tolerance was determined by following the procedure detailed in ASTM D1094-52.

The gum formation was determined by employing the copper dish method set forth in ASTM D910-52T, Section 9].

The copper corrosiontest was conductedin accordance with the instructions stated in ASTM D-53T.

The results of the above tests are tabulated in Table I.

Illustrative of the compounds tested are bis(chloropropyl) methyl phosphonite, BCPMP; bis(chloropropyl) phenyl phosphonite, BCPPP; bis(chloropropyl) methyl thionophosphonate, BCPMTP; and tricresyl phosphate, TCP;

The inclusion of the compound, tricresyl phosphate, in the tables of the instant specification is for the purpose of comparing the compounds of the instant invention with that of a known gasoline pro-ignition additive.

Table I shows the compounds of the instant invention tobe compatible with gasoline in so far as. the common acceptance tests are concerned.

The low-gurn formation. of the compounds of the in.- stant invention make them particularly suitable as. additives for internal combustion engines.

Compounds found satisfactory as: regards the common. gasoline acceptance tests. were then, evaluated as preignition depressants.

A method, familiar to those skill'ed'inthe armor-deter mining a" compounds ability' to reduce the pre-ignitimrv characteristics of a gasoline, is' the oven-test method. Broadly stated, this procedure entails placing known amounts of synthetic engine deposit in a Pyrex heating; boat, with orwi'thouti the pie-ignition. depressant added, nd: having a means for measuring the temperature-attire- 5 oven and the temperature is increased at a uniform rate. The degree of temperature resulting from a sudden/increase in temperature is taken as the glow point of the deposit.

The detailed method employed in determining the glow point of the compounds of this invention is set forth below.

A synthetic engine deposit which contained 38.3 lead sulfate, 33.1% lead oxide, 7.7% lead chloride, 5.9% lead bromide and 15.0% carbon black was prepared by adding the approximate amounts of the compounds together and mixing in a mortar and pestle. To a Pyrex Petrie dish, in. high and /2 in. in diameter was added 0.40 g.:0.1 g. of the synthetic deposit. Over this was burned in 100 ml. portions, gasoline which contained 0.03 volume percent of the different organophosphorus compounds. The amount of additive used was dependent on the phosphorus content of the organophosphorus compound. Enough phosphorus was used to theoretically convert all the lead in the synthetic deposit to lead phosphate. Air was introduced into the gasoline during the burning operation at 2500 cc. a minute in an attempt to convert some of the carbon given off during burning to oxides of carbon. An iron-constant in thermocouple was also placed in the burning fuel in order to obtain some idea as to the temperatures that occurred in the burning step. The majority of the gasoline burned between 150-200" C. and the end gases, approximately 540%, burned between 350 and 450 C. After burning was finished the deposit was scraped from the bottom and the inside wall of the dish and this material then mixed in a mortar and pestle. A glow point determination was then made on the treated deposit.

The apparatus for measuring the glow point consisted of a copper block, 3 in. in length by 2 in. in diameter. A A in. wide collar was at one end of the block. Two vertical holes, 2.5 in. long and cm. in diameter were drilled in the block. The block was heated by a 9 in. by 8 in. electric heating shell which was encased in aluminum. The deposit was placed in a Pyrex heating boat which was 1 in. tall and 10 cm. in diameter. Air was metered through a rotameter and jetted onto the deposit through a steel hypodermic needle. The needle extended 2% inches inside the drilled hole. The temperature was found by means of a Chromel-Alumel thermocouple, which extended into the deposit.

In a typical experiment 0.2 g. of deposit was placed in a Pyrex boat and packed lightly into the Pyrex container. The thermocouple was placed in the deposit and air introduced at the rate of 200 cc./min. The variac which controlled the heating rate was set at 80 volts and was kept at this reading through the experiment. Temperature readings were taken every 10 minutes until 40 minutes had elapsed. After 40 minutes readings were taken in 0.5 or 1.0 minute intervals, and the degree centigrade resulting from a sudden increase in temperature was taken as the glow point of the deposit. Table II lists the average glow point of deposits containing compounds of this invention.

Table II Additive: Average glow point, C. BCPMP 320 BCPPP 325 BCPMTP 324 TCP 327 None 309 the dibromotoluenes. Mixtures of these halohydrocar- It is desirable that the combined organophosphorus and halohydrocarbons contain not more than about by weight of the halohydrocarbons.

1 ,In general, the quantity of additives required in the fuel.

is that necessary to convert (theoretically) all the lead present as tetraalkyl lead into the corresponding lead halide and lead salt of the phosphonite or thionophosphonate concerned. Such a quantity is usually referred to as 1 theory. Greater or smaller quantities may be employed in some circumstances depending upon the particular components of the fuel and the type of engine in which it is intended to be used. In fact one of the merits of the present invention is that it allows greater variation in the quantity of additive employed than is permissible when a halohydrocarbon is used as the sole additive. Even small excesses of halohydrocarbon additives are detrimental in such circumstances whereas with the additives of this invention a substantial excess can be tolerated without adverse results. The preferred range of total additive content of the fuel is from 0.9 to 1.2 theories.

Both the fuels and the compositions suitable for addition to fuels provided by this invention may advantageously contain further compounds known to exert a stabilizing and/or antioxidizing effect on hydrocarbons of the gasoline boiling range. In this connection, 2,4-dimethyl-6- tertiary butyl phenol is a particularly useful additive, other compounds such as hydroquinone, 2,6-ditertiary-butyl-4- methyl phenol, N-phenyl-u-naphthylamine and N,N- dibutyl-p-phenylenediamine may be employed.

The fuels of this invention may be compounded by simply mixing the ingredients in any order. Thus the organophosphorus additive may be added to a leaded gasoline which already contains a halohydrocarbon additive. Alternatively, the organophosphorus may be incorporated in a tetra-alkyl lead fluid containing a halohydrocarbon additive and whole composition blended into the fuel. Again the organo-phosphorus additive may be added to an unleaded gasoline and the tetra-alkyl lead fluid containing a halohydrocarbon scavenger added subsequently.

Pursuant to the requirements of the patent statutes, the principle of this invention has been explained and exemplified in a manner so that it can be readily practiced by those skilled in the art, such exemplification including what is considered to represent the best embodiment of the invention. However, it should be clearly understood that, within the scope of the appended claims, the invention may be practiced by those skilled in the art, and having the benefit of this disclosure, otherwise than as specically described and exemplied herein.

That which is claimed as patentably novel is:

11. A composition of matter represented by the formu a:

in which R is selected from the group consisting of hydrogen and lower alkyl and phenyl radicals; Y is selected from the group consisting of lower alkyl and phenyl radicals and n is an integer from 1 to 2 inclusive.

2. As a new composition of matter, bis(betachloropropy1)methyl phosphonite.

3. As a new composition of matter, bis(betachloropropyl)phenyl phosphonite.

4. As a new composition of matter, bis(betchloroprov ply)methyl thionophosphonate.

7 5. A method of preparing the halogenated thionoesters of primary phosphonic acids of the formula OOHzCHC1-R s--Y o-cH20B1oL-R.

of primary phosphonic acids in accordance with claim 5, in which the haloester of phosphonousacid is bis(betachloropropy1)methyl phosphonite.

References Cited in the file of this patent UNITED STATES PATENTS Campbell Aug. 13, 1946 Withrow Sept. 9, 1947 Teeters Ian. 25, 1949 Ballard et a1 Sept. 2-2, 1953 OTHER REFERENCES Kosolapofl: Organo Phosphorus Compounds, page 185 1950), John Wiley & Sons, Inc., New York, NY.

Claims

1. A COMPOSITION OF MATTER REPRESENTED BY THE FORMULA:

5. A METHOD OF PREPARING THE HALOGENATED THIONO ESTERS OF PRIMARY PHOSPHONIC ACIDS OF THE FORMULA