US3474151A

US3474151A - Method for the decomposition of octane degrading components present in tertiary butyl alcohol-gasoline additive

Info

Publication number: US3474151A
Application number: US589508A
Authority: US
Inventors: Henry R Grane
Original assignee: Atlantic Richfield Co
Current assignee: Atlantic Richfield Co
Priority date: 1966-10-26
Filing date: 1966-10-26
Publication date: 1969-10-21
Anticipated expiration: 1986-10-21
Also published as: DE1643590A1; JPS5250763B1; GB1172758A

Description

United States Patent 3,474,151 METHOD FOR THE DECOMPOSITION OF OCTANE DEGRADING COMPONENTS PRESENT IN TER- TIARY BUTYL ALCOHOL-GASOLINE ADDITIVE Henry R. Grane, Springfield, Pa., assignor to Atlantic Richfield Company, Philadelphia, Pa., a corporation of Pennsylvania No Drawing. Filed Oct. 26, 1966, Ser. No. 589,508 Int. Cl. C07c 29/24 US. Cl. 260-643 4 Claims ABSTRACT OF THE DISCLOSURE Method for decomposing octane degrading components, particularly organic peroxides, in tertiary butyl alcohol containing such components by heating the tertiary butyl alcohol to from 375 F. to 475 F. for from 1 to 10 minutes.

This invention relates to a method for decomposing octane degrading components present in tertiary butyl al cohol. More particularly, this invention relates to the decomposition of octane degrading components present in tertiary butyl alcohol produced by the liquid phase oxidation of isobutane and to said alcohol and gasoline containing the same.

Although for many years tetraethyl lead and similar lead compounds have been added to gasolines to improve their anti-knock characteristics, in recent years there has been a considerable amount of work directed toward the production of gasolines which are either free of tetraethyl lead or are of low tetraethyl lead content. There are two important reasons for reducing the lead content of gasolines, the first being that lead produces harmful deposits in internal combustion engines which requires the addition to the gasoline of various types of scavengers and deposit modifiers. In addition, there has been a gradually increasing pressure from public health authorities to reduce or eliminate entirely the lead content of gasoline because of the toxic effect thereof.

Carburetor icing is another problem of modern automotive engines. Carburetor icing causes stalling of the engine in cool, humid weather, particularly when the englue is cold. It has been found that when tertiary butyl alcohol (2-methyl-2-propanol) is added to gasoline the carburetor anti-icing properties of the gasoline are markedly improved and, in addition, since tertiary butyl alcohol is an anti-knock compound the addition of tertiary butyl alcohol to gasoline provides a two-way improvement to the gasoline, i.e. it improves the anti-knock characteristics and the anti-icing properties of the gasoline. In general the amount of tertiary butyl alcohol added to gasoline for these purposes ranges in amount from 1 volume percent to 20 volume percent based on the total volume of the fuel.

One of the most convenient methods of making tertiary butyl alcohol is by the oxidation of isobutane in the liquid phase using molecular oxygen. In this method the oxidation is carried out, preferably in the absence of catalytic materials, at temperatures in the range of from about 200 F. to 300 F. or preferably in the range of from 260 F. to 290 F. at pressures of from 300 p.s.i. to 700 p.s.i. although these conditions can be varied somewhat. When the tertiary butyl alcohol is produced by this method there is also produced tertiary butyl hydroperoxide in amounts which may equal or exceed the amount of tertiary butyl alcohol. In addition ditertiary butyl peroxide and other oxygenated compounds are produced in small amounts. The tertiary butyl hydroperoxide is a valuable oxidizing agent which may be used in many ways, for example, to oxidize olefins to epoxides. The hydroperoxide may either be separated from the alcohol for 3,474,151- Patented Oct. 21, 1969 this purpose or the entire product of the isobutane oxidation, i.e. the tertiary butyl hydroperoxide which has not been separated from the tertiary butyl alcohol and minor oxygenated compounds, may be used for the oxidation reaction. The residual tertiary butyl alcohol by either method does, however, contain some tertiary butyl hydroperoxide and peroxides. Although these compounds may be present in relatively small quantities in the tertiary butyl alcohol they have a large degradation effect on the octane characteristics of the gasoline. It has been found that the total peroxy content of the alcohol to be added to gasoline should be less than 100 p.p.m. by Weight of the tertiary butyl alcohol.

In accordance with this invention a method has been found for treating tertiary butyl alcohol containing hydroperoxides and peroxides to decompose these components which are octane degrading.

It is an object of this invention therefore to provide a method for the decomposition of octane degrading components in tertiary butyl alcohol.

It is another object of this invention to provide tertiary butyl alcohol which has been treated to decompose octane degrading components.

It is another object of this invention to provide gasoline containing tertiary butyl alcohol treated to decompose octane degrading components.

Further objects of this invention will be apparent from the following detailed description and from the claims.

It has been found that if tertiary butyl alcohol containing small quantities of hydroperoxides and peroxides is heated to a temperature in the range of from 375 F. to 475 F., preferably from 400 F. to 450 F., for at least 1 minute and generally from 1 to 10 minutes either in the vapor phase or the liquid phase that the hydroperoxides and peroxides are decomposed substantially completely into compounds which are not octane degrading. Since tertiary butyl alcohol starts to dehydrate even at 450 F. the shorter times should be used with the higher temperatures, but above 475 F. the dehydration is so rapid it destroys the desired alcohol even with very short times. Pressures ranging from atmospheric to 1000 p.s.i.g. or higher can be used, depending upon Whether the reaction is carried out in the gas phase or liquid phase. However, it is desirable to utilize sufiicient pressure to carry out the treatment in the liquid phase since this requires smaller equipment and thus less capital investment. In general pressures of from 500 p.s.i.g. to 700 p.s.i.g. are desirable primarily for economic reasons.

The examples which follow are provided to illustrate more specifically the invention. It will be understood, however, that these examples are merely illustrative of a large number of runs which have been carried out to de- EXAMPLE I A sample of isobutane was oxidized in the liquid phase utilizing molecular oxygen and the oxidation product was utilized to epoxidize propylene. After the propylene oxide had been separated by distillation there remained tertiary butyl alcohol containing 1.2 weight percent tertiary butyl hydroperoxide, 0.4 weight percent ditertiary butyl peroxide and 1.3 weight percent allyl tertiary butyl peroxide based on the weight of the tertiary butyl alcohol plus impurities. A sample of this tertiary butyl alcohol was heated for 8 minutes at 406 F. under a pressure of 602 p.s.i.g. The product was found to contain less than 10 p.p.m. by weight of each of the hydroperoxide and peroxide impurities. This run demonstrates that heat treatment of tertiary butyl alcohol in accordance wih this invention decomposes substantially completely the hydroperoxide and peroxide impurities in the tertiary butyl alcohol.

EXAMPLE II In order to demonstrate that the heat treatment of tertiary butyl alcohol in accordance with his invention decomposes the octane degrading components, three comparative tests were made. To a premium grade gasoline containing 3 ml. of tetraethyl lead per gallon was added 10 volume percent based on the total volume of the fuel of highly purified tertiary butyl alcohol which was free of hydroperoxides and peroxides and contained less than one weight percent of total impurities. Another 10 percent blend in the same gasoline was made with tertiary butyl alcohol containing substantially the same quantities of hydroperoxides and peroxides as the tertiary butyl alcohol described in Example I before heat treatment. Another sample of this impure tertiary butyl alcohol was heat treated at 419 F. in the liquid phase at 600 p.s.i.g. for 3 minutes. The product from this heat treatment was utilized to make a 10 volume percent blend with the same gasoline utilized in the first two blends of this example. Each of these three blends was tested for octane number both by the Research Octane Method (ASTM Method D-908) and the Motor Octane Method (ASTM D-357). The blend containing the impure tertiary butyl alcohol before heat treatment was found to degrade the Research Octane number by 2.2 numbers below the Research Octane number for the gasoline blend containing the pure tertiary butyl alcohol. When the gasoline containing the impure tertiary butyl alcohol was tested by the Motor Method it was found that the octane number was lowered by 1.07 numbers below the Motor Method octant number of the gasoline containing the pure tertiary butyl alcohol. The gasoline containing the tertiary butyl alcohol which had been heat treated to decompose the octane degrading components had the same Research Octane number as the gasoline containing the pure tertiary butyl alcohol and a slightly higher (+0.26) Motor Octane number than the gasoline containing the pure tertiary butyl alcohol. These runs demonstrate that the heat treatment of tertiary butyl alcohol in accordance with this invention decomposes the octant degrading components of the impure material and gives a product which is the same as chemically pure tertiary butyl alcohol.

I claim:

1. A method for decomposing octane degrading components from tertiary butyl alcohol which consists of heating the tertiary butyl alcohol containing small quantities of organic peroxides to a temperature in the range of from 375 F. to 475 F. for a time of from 1 minute to 10 minutes.

2. The process according to claim 1 wherein the temperature is in the range of from 400 F. to 450 F.

3. The process according to claim 1 wherein the tertiary butyl alcohol is produced by the oxidation of isobutane.

4. The process according to claim 1 wherein the temperature is in the range of from 400 F. to 450 F. and the time is in the range of from 5 minutes to 9 minutes.

References Cited UNITED STATES PATENTS 1,845,665 2/1932 Isham 260682 1,984,725 12/1934 Britton et al. 260643 2,478,270 8/1949 Ipatiefr et a1 260682 2,615,921 10/1952 Dougherty ct al.

2,671,121 3/1954 Banes et al. 260682 2,700,677 1/1955 Bowen et al. 260643 3,351,635 11/1967 Kollar 260682 OTHER REFERENCES Tobolsky et al., Organic Peroxide's (1954), pp. 92, 93, QD181.01T6.

Hawkins, Organic Peroxides, (1961), pp. 7 and 13 to 17, QD305.H7HJ 8.

LEON ZITVER, Primary Examiner J. E. EVANS, Assistant Examiner U.S. Cl. X.R. 44-56; 260349.5