US3083088A - Leaded gasoline containing aromaticsubstituted esters - Google Patents

Description

3,083,088 LEADED GASOLINE CONTAINING AROMATHC- SUBSTITUTED TESTERS Dennis R. Carlson, Park Forest, Everett N. Case, Hotnewood, and Seymour I-I. Patinkin, Chicago, ilh, assignors, by mesne assignments, to Sinclair Research inc, New York, N.Y., a corporation oi Deiaware No Drawing. Filed June 15, 196i Ser. No. 36,150 9 Claims. (Cl. t t-69) This invention relates to an improved gasoline composition which is of high octane number, which contains a lead compound as an anti-knocking agent, and also contains an octane rating booster.

By and large, modern gasolines for use in spark-ignited internal combustion engines, e.g., automotive and airplane engines 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 to suppress knocking. Generally this agent is an alkyl lead compound especially a tetra-lower alkyl lead, usually a small amount within the range from about 0.5 to 3.0 cc. per gallon, or even as much as approximately 5 or 6 cc. per gallon. Tetra-ethyl lead is the most widely used antiknock agent, and is effective in raising the octane and thereby reducing the knock caused by abnormal combustion of gasoline of inferior octane rating. Other lead compounds, such as the lower-alkyl lead carboxylates disclosed in copending application S.N. 855,006, filed November 24, 1959, are useful as anti-knock agents. However, the quantity of lead compound which may be used in a gasoline is limited by decreasing efiectiveness at higher percentages, and by the fact that lead compounds cause lead-containing deposits in the cylinders as well as by economic, health and legal considerations.

Several methods are used for determining the octane rating of a gasoline and each method usually gives a different figure; for example, the motor method of determining octane rating generally gives a lower figure than the research method. The spread between the two figures is termed the sensitivity of the fuel. Gasolines are sold on the basis of their research octane number but the make of the car and the type of driving determines whether it operates closer to the motor method or research method rating; however, the road octane is usually, numerically, in the space between the two. A gasoline having motor methodand research method octane numbers which are closer is less sensitive in its performance to variations in operating conditions.

In accordance with this invention, certain gasolinecompatible, i.e., soluble, miscible or dispersible, aromatic esters are incorporated in a leaded gasoline as an octane booster. The improvement in the gasoline is sometimes greater in the motor method of determining octane rating and sometimes greater when the octane is determined by the research method. The fuel may have less spread between its research method number and its motor method number, and would accordingly be considered as less sensitive.

The ester incorporated in gasoline according to this invention is a primary or secondary monoor di-aryl substituted lower alkyl ester of a lower carboxylic acid, that is, one which contains the residues of a lower carboxylic acid and a primary or secondary lower aliphatic alcohol having an aryl substituent. The ester may be represented by in which R is a monovalent hydrocarbon radical, preferably of 1-6 carbon atoms and either or both R and R are hydrocarbon-ring aryl radicals of up to 10 carbon atoms in the ring structure, that is, phenyl or naphthyl. If one of R or R is non-aryl, it is a hydrogn or monovalent hydrocarbon radical, e.g. an alkyl radical of 14 carbon atoms. The hydrocarbon radicals and the carbon atom adjacent R may be substituted, for example with alkyl, alkoxy or hydroxy. The R group may be aryl or lower alkyl, preferably a lower alkyl group having 1-4 carbon atoms. The selected substituents will usually provide an ester of up to about 20 carbon atoms. The acid residue or acyl group 2 to 7 carbon atoms. Exemplary preparations of useable esters are as follows:

PREPARATION OF oc-PHENYL ETHYL ACETATE To a solution of 122 grams (1.0 mole) a-phenyl ethyl.

alcohol and 95 grams (1.2 mole) pyridine in 200 ml. anhydrous ether was added dropwise ml. (1.2 mole.) acetyl chloride. The reaction occurred immediately with evolution of heat and precipitation of pyridine hydrochloride. The heat of reaction maintained the temperature at 40 to 45 C. through most of the addition. The reaction mixture was allowed to cool to room temperature after which an equal volume of water was added to the reaction mixture to dissolve the pyridine hydrochloride and hydrolyze any unreacted acetyl chloride. The ether solution was washed with dilute NaHCO solution, and then water, and dried over anhydrous MgSO The ether was stripped off and the crude product distilled under reduced pressure.

The fraction boiling at 73 C. at 3.0 mm. Hg (220 C. at 760 mm. Hg) was collected for a 92% yield of a-phenyl ethyl acetate. 2

ANALYSIS [nnNsr'rYgirozes] Cale. Det.

Sap. equiv 342 332. Percent C 73. 25 73. 22 Percent H 7. 33 7. 34

PREPARATION OF 1,2-DIPHENYL ETHYL Toa solution of 50 grams (0.25 mole) 1,2-diphenyl ethyl alcohol and 24 grams (0.3 mole) pyridine in 100 ml. anhydrous ether was added dropwise 22 ml. (0.3 mole) acetyl chloride. The reaction occurred immediately evolving heat and precipitating pyridine hydrochloride. The heat of reaction held the temperature at 40-45 C. through most of the addition of ace-tyl chloride. After cooling the reaction mixture to room temperature an equal volume of water was added to dissolve the pyridine hydrochloride and hydrolyze any unreacted acetyl chloride. The ether solution was Washed with dilute NaHCO solution and then Water, and dried over anhydrous MgSO After stripping oi the ether the crude product was distilled under reduced pressure.

The fraction boiling at 122 C. at 0.8 mm. Hg (319 C. at 760 mm. Hg) (reported Hauser, Shivers and Skell, JACS 67, 409412 [1945], B.P. 312 C. at 760 mm. Hg) was collected for a 75% yield of 1,2-diphenyl ethyl acetate.

ANALYSIS [DENSITY2+=1.0794] Cale. J Det.

Sap. equiv 234 210 Percent C 80. 00 80. 46 Percent H 6. 67 6.76 a

The ester is included in the gasoline composition in the ratio of from about 1 to 50 moles of ester per mole of lead compound and sufiicient to increase the octane number of the leaded gasline. The molar ratio of ester to lead compound is preferably about 2 to 40. In terms of volume, the fuel usually contains about 0.1 to 3 volume percent of the ester, preferably about 0.2 to 1.5%, and in amount suflicient to increase the octane rating of the fuel. The concentration of the additive is important in that larger percentages may decrease the octane rating of the gasoline below the rating of the base fuel. Also, the optimum range of effectiveness of the octane booster varies with the lead content of the gasoline. In general, with greater amounts of, for example, tetraethyl lead, not only is the octane increased, but the octane boosting ability of the ester is also increased and the optimum range for this additive is slightly raised.

Gasolines are usually blends of low boiling mineral oil hydrocarbon fractions derived by distillation, cracking, and other refining and chemical conversion processes practiced upon crude petroleum. The gasoline will contain varying proportions of paratfins, olefins, naphthenes and aromatics and generally will boil primarily in the range of about 100 to 425 F. The gasoline of this invention has aromatic components which are at least about volume percent, preferably at least about 40 percent of the hydrocarbon fuel. A typical premium gasoline besides a small amount of lower-alkyl lead compound as an anti-knock agent, may also contain small amounts of other non-hydrocarbon constituents used to impart various properties to the gasoline in its use in internal combustion engines, e.g. scavengers, corrosion inhibitors, etc.- Such gasolines frequently have a research method octane number of about 90 to 105 and a motor method octane number of about 8098. The most widely used tetra-lower-alkyl lead compound added to gasolines as an anti-knock agent is tetra-ethyl lead. TEL Motor Mix is used in commercial practice to add tetraethyl lead and scavengers to the gasoline. Motor Mix contains 59.2% tetra-ethyl lead, 13.0% ethylene dibromide, 23.9% ethylene dichloride and 3.9% hydrocarbon diluent, dyes, etc. Several gasoline blends were used in the examples and tests reported below. Base gasoline M was a naphtha reformate distillation tower bottoms fraction which had an API gravity of 34.1

and contained 25.1% paraflins, 3.2% naphthenes and 71.7% aromatics. The fraction had an ASTM distillation of:

IBP F 313 50% F 334 F 368 EP F 442 Rec. "percent" 98.5 Res. do 1.0 Loss do 0.5

Gasoline blend D comprised 28.4% of these tower bot-- toms, 28.4% lightfiuid catalytically cracked gasoline, 19.0% mixed xylenes, 19.0% alkylate fuel and 5.2% butane. This gasoline had an API gravity of 53.0 and a bromine number of 35.0. It analyzed as 34.9% paraffins, 15.1% olefins, 7.1% naphthenes and 42.9% aromatlCS.

Its ASTM distillation was:

13? F..- 92 10% F 133 50% F 256 90% F 329 EP F 403 Percent rec 98.0 Percent res 1.0 Percent loss 1.0

Gasoline blend E had a bromine number of 38.5 and and analyzed as 7 Vol. percent Parafiins 34.3 Olefins 27.2 Naphthenes 4.7 Aromatics 33.8 Sulfur (weight percent) 0.0213

Samples of these base gasolines were obtained and mixed with varying amounts of tetraethyl lead and phenylsubstituted lower alkyl esters of lower carboxylic acids. The octane determinations for each sample are reported in Table I below. Samples 1-6 and 71-76 contained 2.9 cc./gal. TEL added as Motor MiX. Samples 1116 and 41-46 contained 3 cc./ gal. of pure tetraethyl lead. The rest of the samples contained 6 cc./gal. of pure tetraethyl lead.

a Table I BASE: BLEND E (2.9 00. TEL/GAL.)

V 1 Octane Change from base 0 Sample Additive percent Motor Research Motor Research method method method method 1 None 88.5 99.5 2 a-ptiicenyl ethyl ace- 0.25 88.4 99.6 0.1 +0.1

Table IContinued Table l-Continued BASE; BLEND D (a co. TEL/GAL.) BASE: BLEND D 0o. TEL/GAL.)

V 1 Octane Change from base V01 Octane Change from base 5 Sample Additive per sample Addmve 2%; Motor Research Motor Research cent Motor Research Motor Research method method method method method method method method 91 None 94.3 106.5 11 None 92.4 109.5 12 a-ltfllenyl ethyl ace- 0.25 92.7 103.7 +0.3 +0.2 5. 5533 94.8 105.9 +0.5 +0 4 103-5 0 94.9 107.1 +0.0 +0 0 i823 ig-g 95.5 107.3 +1.2 +0 8 9217 10412 +03 +07 +0 8 BASE: BLEND D (0 0o. TEL/GAL.) BASE: BLEND D (0 CO. TEL/GAL.)

None 04.5 106.4 "6-- None 95.0 10 6111201312; e thyl 1.0 95.1 100.0 +0.6 .2 a-phenylethylace- 0.50 06.0 106.3 95.1 106.9 5 tate- 0 95.0 100.7 +0.5 +0 3 95.1 100.7 +0.0 +0 3 g M O 7 95.0 100.9 +0.5 +0 5 BASE: FRACTION M 0 00. TEL/GAL.)

BASE: BLEND D (6 CC. TEL/GAL.) 1H 1030 112 fi-rghenyltethyl 1.25 94.7 103.4 +0.5 +0.4

6112037 8 31 None 94.5 105.9 32--. an enyletnyince- 1. 75 90.0 107.4 +2.1 +1.5 a 0. 95.2 103.6 1.0 0.6 9549 95.0 100.7 11.4 1:07 39-; 95.4 103.0 +1.2 +0.0 107 1 +231 +132 95.4 105.5 +1.2 +0.5 90.3 107 0 +1.8 +1.1

3 The above examples, which are to be considered 111110- (3 OG TEL/GAL) trative only and not limiting, show that the addition of the enumerated esters to a leaded gasoline boosts the 921 1024 octane rating of gasoline fuels. 92.3 102.5 +0.2 +0.1 It is claimed; 92.8 102.7 +0.7 +0.3 35 1. A leaded gasoline consisting essentially of base Egg g ig-g i8 2 hydrocarbon gasohne containing at least about 30% aroig 102:7 1 matic hydrocarbons, a small amount of lower alkyl lead anti-knock agent sufficient to reduce knock and about BASE. FRACTION M (6 TEL/GAL) 40 l to 50 moles per mole of lead compound and sufliclent to improve the octane rating of the leaded gasoline of N 94 3 103 4 a gasoline-compatible aryl substituted lower alkyl ester g g 135* 1 10317 15 ""153 of a lower carboxylio acid of u to about 20 carbon atoms tatc. and having the formula:

1.50 95.1 103.0 +0.8 +0.2 1.75 94 s 103.0 +0 5 +0.2 H H 2.00 95 1 103.5 +0 23 +0.1 a 2.25 955 103.8 +1.3 +0.4 2.50 95 7 103.8 +1 4 +0.4 H i H 2.75 95 0 103.7 +0 7 +0.3 7 0 95 5 103-6 2 in WhlCh R is a monovalent hydrocarbon radical, R

and R are selected from the group consisting of hydro- BASE: BLEND D /GAL.) gen and monovalent hydrocarbon radicals, with the proviso that at least one of R and R is a hydrocarbon-ring 01 None 95.1 105. 7 a yl radical 0t up to 10 carbon atoms in the ring structure. 02"--- fl-i g y 105-5 2. A gasoline composition according to claim 1 1n 95,3 1 5,7 0 which R has 1 to 6 carbon atoms.

3 105-7 0 3. A gasoline composition according to claim 1 con- 58 105.9 +0.7 +0.2 90.0 1059 +0.9 +0.2 taming about 2 to 40 moles of ester per mole of lead 95.0 105.7 +0.5 0 95.9 100.0 +0.8 +0.5 compound 4. A gasoline composition according to claim 1 containing at least about 40% aromatic hydrocarbons. BASE: BLEND E 2.9 00. TEL/GAL.) 6O 5. A gasoline composition according to claim 3, containing at least about 40% aromatic hydrocarbons in which the ester is an acetate.

-1 None 88.4 99.4 i2..-" 1,2-diphenyl ethyl 0.50 88.6 99.5 +0.2 +0.1 6. A gasoline composition according to claim 5 in acetate 8&6 99A 0 which the ester is a-phenyl ethyl acetate.

.1 5 7. A gasoline composition according to claim 5 in 88:8 9910 i014 1 which the ester is fi-phenyl ethyl acetate.

8. A gasoline composition according to claim 5 in BASE: BLEND D (6 CG TEL/GAL) which the ester 1s 1,2-d1phenyl ethyl acetate.

9. A gasoline composition according to clam 5 in which the ester is ,B-phenyl ethyl benzoate.

s1 None 94.9 105.0 82--. m g r fiz yl ethy 1.50 9 100.0 +0.9 +0.4 References Cited in the file of this patent 2. 97.1 100.2 +2.2 inc FOREIGN PATENTS 1063 42,139 Australia Oct, 8, 1958 571,921 Belgium Oct. 10, 1958

Claims (1)

1. A LEADED GASOLINE CONSISTING ESSENTIALLY OF BASE HYDROCARBON GASOLINE CONTAINING AT LEAST ABOUT 30% AROMATIC HYDROCARBONS, A SMALL AMOUNT OF LOWER ALKYL LEAD ANTI KNOCK AGENT SUFFICEINT TO REDUCE KNOCK AND ABOUT 1 TO 50 MOLES PER MOLE OF LEAD COMPOUND AND SUFFICIENT TO IMPROVE THE OCTANE RATING OF THE LEADED GASOLINE OF A GASOLINE-COMPATIBLE ARYL SUBSTITUTED LOWER ALKYL ESTER OF A LOWER CARBOXYLIC ACID OF UP TO ABOUT 20 CARBON ATOMS AND HAVING THE FORMULA: