November 1952
INDUSTRIAL AND ENGINEERING CHEMISTRY
Ipatieff, V. N., and Schmerling, L. (to Universal Oil Products Co.), U. 5. Patents 2,347,266 (April 25, 1944) and 2,348,700 fMav “ 9. -, 19441. ----, M&lister, S. H., and Perry, N. E. (to Shell Development Co.), U. S. Patent 2,394,797 (Feb. 12, 1946). McMillan, F. M., and Cheney, H. A., Ibid., 2,393,051 (Jan. 15, 1946).
Mavity, J. M., Pines, H., Wackher, R. C., and Brooks, J. A., IND. ENQ.CHEM.,40,2374 (1948). N. V. de Bataafsche Petroleum Maatschappij, Dutch Patent 50,385 (May 15, 1941). Perry, N. E. (to Shell Development Co.), U. S. Patent 2,394,803 (Feb. 12, 1946). Pines, H., chapter entitled “Isomerization of Alkanes,” in “Advances in Catalysis and Related Subjects,” Vol. 1, New York, Academic Press, Inc., 1948. Pines, H. (to Universal Oil Products Co.), U. S. Patent 2,405,516 (Aug. 6, 1946). Ibid., 2,406,967 (Sept. 3, 1946). Ibid., 2,436,484 (Feb. 23, 1948). Pines, H., Xvetinskas, B., Kassel, L. S., and Ipatieff, V. N., J. Am. Chem. Soc., 67, 631 (1945).
2721
(26) Pines, H., and Wackher, R. C. (to Universal Oil Products Co.), U. S. Patent 2,406,633 (Aug. 27, 1946). (27) Ibid., 2,406,634, (28) Ibid., 2,418,724 (April 8, 1947). (29) Schuit, G. C. A. (to Shell Development C o . ) , U. S. Patents 2,265,548 and 2,265,870 (Dec. 9, 1941). (30) Schuit, G. C. A., Hoog, H., and Verheus, J., Rec. trav. chim., 59, 793-810 (1940). (31) Sensel, E. E., Smith, W. R., and Goldsby, A. R. (to The Texas Co.), U. S. Patent 2,438,421 (March 23, 1948). (32) Shoemaker, B. H., and Evering, B. L. (to Standard Oil Co. of Indiana), Ibid., 2,399,765 (May 7, 1946). (33) Smith, W. R., and Goldsby, A. R. (to The Texas Co.), Ibid., 2,398,563 (April 16, 1946). (34) Standard Oil Development Co., Brit. Patent 598,952 (March 2, 1948). (35) Universal Oil Products Co., Ibid., 590,488 (July 18, 1947). (36) van Peski, A. J. (to Shell Development Co.), U. S. Patent 2,271,043 (Jan. 27, 1942). RECEIVED for review January 17, 1952.
ACCEPTEDJune 27, 1952.
as a Gasoline Antioxidant MINOR C. K. JONES, ALLEN R. JONES, AND BARNEY R. STRICKLAND Esso Laboratories, Standard Oil Development Co., Linden, N. J.
W
ITH most reagents, 2,6-di-tert-buty1-4-methylphenol does not exhibit behavior typical of phenols, the hydroxyl group being very inert. This compound is of the hindered phenol class described by Stillson et al. (9),and its chemical inertness has been attributed to steric hindrance of the two tertiary-butyl groups adjacent to the functional group. With severe treatment, however, it does undergo some of the reactions of a phenol. For example, i t will react with metallic sodium in liquid ammonia and with the Zerewitinoff reagent for active hydrogen. I n addition t o Stillson et al., Coggeshall ( d ) , McKinley (6),and Wasson and Smith (13) have published information on the chemical behavior of the trialkylphenols. The relative chemical inertness of this material gives it desirable properties for use as an antioxidant in petroleum products. It is active enough chemically t o possess good antioxidant potency and yet because of its relative inertness is not easily lost from an oil. Its thermal stability and resistance t o oxidation by air make it essentially free of the tendency to form induction system deposits in engines, to which some of the currently used fuel antioxidants are subject. Although 2,6-di-tert-butyl-4-methylphenolhas found application as an antioxidant in various products, such as lubricating oils, waxes, synthetic rubber, polymers, etc., the present paper is restricted to a discussion of its use in gasolines and in concentrated tetraethyllead mixtures.
The vapor pressure characteristics of 2,6-di-tert-butyl-4-methylphenol compared to the properties of other antioxidants are given in Table 111. These vapor pressure data were obtained by means of distillations at reduced pressures. Further data on the physical properties of alkylated phenols are given by Stevens (8) and Pardee and Weinrich (7). The trialkylphenol is somewhat more volatile than the other two antioxidants.
TABLE I. PRECIPITATION POINTFOR SOLUTIONS OF ~,~-DI-~W&BUTYL-~-METHYLPHENOL Concn., Wt. % Solvent Pptn. Pt., Hydrocarbons 25 -36 Toluene 10 Toluene 331/a 50 41 Toluene 75 85 Toluene 20 - 36 Aromatic solvent naphtha 33 40 Aromatic eolvent naphtha 60 88 Aromatic solvent naphtha - 24 10 Iso-octane 32 25 Iso-octane 40 63 Iso-octane Oxygenated solvents 32 15 Isopropyl alcohol Isopropyl alcohol 33’/a > 75 65 50 Acetone 50 4 Methyl ethyl ketone 27 60 Ethyl acetate
O
F.
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PHYSICAL PROPERTIES
at 700 C. This antioxidant is a white crystalline solid, I t s solubility in several hydrocarbon and oxygenated solvents has been determined and the data are presented in Table I. It may be noted that 2,6-di-tertbutyl-4methylphenolis very soluble in these solvents, being most soluble in toluene of the hydrocarbons and in methyl ethyl ketone of the oxygenated solvents investigated. Data presented in Table I1 show this inhibitor to have very high solubility in gasolines and to be practically insoluble in water.
TABLE 11.
ANTIOXIDANTS I N GASOLINESAND WATERAT 70” F.
SOLUBILITY O F
Grams of Soluts/100 M1. of Solvent Motor Aviation Antioxidant gasoline“ gasoline” Water 2,6-Di-te~t-butyl-4-methylphenol 82 85
