US2194496A - Power alcohol - Google Patents

Description

Patented Mar. 26, 1940 I m'ro STATES- POWER ALCOHOL lLeo M. Christensen, Atchison, lKana, assignor to The Chemical Foundation, Incorporated, a corporation of Delaware No Drawing.

i Claims.

This invention relates to power alcohol, more particularly to specially denatured alcohol-gasoline blends.

The present application is related in subject matter to my application Serial No. 191,115, filed of even date herewith.

Ethyl alcohol, which is to be employed in the industries, underthe requirements of the law must be denatured. Such denaturation comprises essentially the addition of a substance which is soluble or miscible with the alcohol and which is of such characteristics as to render the alcohol unpotable. An efiective denaturant for this purpose is one which masks the taste of the alcohol, renders such alcohol distasteful and nauseating, and which is difficult to separate from the alcohol.

The denaturation of alcohol which is intended for employment as a power fuel presents special problems which do not obtain in other uses of industrial alcohol. A power alcohol denaturant, in addition to the foregoing properties, common to all denaturants, should also be of such a character that it does not tend to corrode the metal parts of the engine nor to influence unfavorably the quality of the petroleum fraction with which it is blended. While many types of denaturants have been proposed heretofore, these were intended for employment with the usual industrial alcohol and were designed or chosen to comply with the legal requirements. But little, if any, thought has been given to the possibility of utilizing denaturants for power alcohol which, in addition to satisfying the legal requirements, also insure positive technological advantages.

The present invention relates to a denaturant particularly designed for addition to power alcohol which, in use, i. e., in the ultimate hydrocarbon-alcohol blend, subserves many correlated technically advantageous functions in addition to its primary function of denaturation.

The power alcohol fuels contemplated herein comprise blends of hydrocarbon oils, particularly gasoline, and alcohol. Since the great proportion of the gasoline marketed consists of cracked gasoline, the ultimate products producible under this invention include such cracked gasoline as a major component. Such power alcohol fuels thus include homogeneous blends of from 5 per cent., or less, up to 50 per cent, or more, of specially denatured alcohol, with the remainder made up of natural or cracked gasoline, or mixtures of such gasoline, together with, if desired, benzene or other fuel values.

In recent years it has widely been acknowledged Application February 17, 1938, Serial No. 191,116

that the general efilciency of a gasoline motor may be increased considerably by insuring sufficient top cylinder lubrication. For this purpose, it is now a common practice to add to the gasooline a modicum of a high boiling oil, such as a suitable vegetable oil, the essential function of which is to lubricate the upper part of the cylinder. Such products are marketed as separate commodities, which may be purchased at the filling station, and which are adapted to be added to the gasoline in the tank of the car. Recently certain standard blends of premium gasolines are being sold in which such a top cylinder lubricating oil is a regular component.

Under one phase of the present invention, a gasoline-alcohol blend is produced which contains an addition agent which, at the one time, serves to denature the alcohol and insure a homogeneous blend of this with gasoline, and effectively to lubricate the upper cylinder of the motor in which it is used. In short, the invention provides for the utilization of a combined alcohol denaturant and a top cylinder lubricant. As will be seen more fully, these two major beneficial functions are secured by employing a cheap and bountiful commercial product, namely, synthetic methanol.

Many gasolines on the market, notably those produced by vapor phase cracking methods, contain certain constituents (usually considered to be the diolefines) which present a decided tendency to form gums. In many circumstances, even after such cracked products are treated, as for example with sulfuric acid, or in clay towers, this gum-forming tendency persists. It is a generally accepted fact, however, that such gum-forming constituents do possess some advantages, for they do tend to increase the octane rating of the gasoline. A specific phase of the present invention is to utilize such high anti-knock value gasolines in.a blend with ethanol and a special type of denaturant which advantageously coacts in the blend to inhibit the formation of .gums.

According to a preferred embodiment of the invention, a gasoline-alcohol blend is produced which contains a denaturant which subserves all the enumerated beneficial functions of denaturation, gum inhibition, top cylinder lubrication and effective blending. Such a denaturant, as will be seen, comprises a blend of crude synthetic meth- 50 anol and crude hardwood methanol. The denaturant concentrate itself, therefore, comprises a product which is as economical as it is unexpectedly eflicacious.

The potentialities of these new denaturants for 66 the stated purposes will more readily be appreciated from a consideration of their composition.

As is known, methanol may be prepared synthetically by the hydrogenation of carbon monoxide. Such a'process has been practiced commercially for some years. Generally stated, this synthesis is effected by passing carbon monoxide and hydrogen, in definitely established proportions, under a pressure of 150 atmospheres, more or less, and at a temperature of the order of 400 0., over suitable hydrogenating catalysts, such as the oxides of copper, chromium, zinc, and the like. The reaction products are condensed and the condensate comprises crude synthetic methanol. This condensed reaction product is a complex mixture of methyl alcohol and a large number of higher primary and secondary monohydric alcohols, as well as complex unidentified compounds of high molecular weight. Included in this crude product are aliphatic alcohols, containing up to 9 or 11 carbon atoms.

As a result of considerable experimentation, it has been determined that the higher boiling monohydric alcohols, particularly those containing from 9 to 11 carbon atoms, have a specific lubricating effect in a gasoline motor and constitute excellent top cylinder lubricants. Such higher alcohols are miscible with ethyl and methyl alcohol and thus; to some extent, also function as denaturants.

In one embodiment of the invention, the crude methanol is employed directly as an addition agent to ethyl alcohol which is to be blended with gasoline. For this purpose a relatively large amount of the crude methanol may be employed, as for example, of the order of 5 per cent., or more, of the methanol to the ethyl alcohol. This denaturant addition agent contains lower alcohols, i. e., methyl alcohol, propyl alcohol, isobutyl alcohol, and the like, which have boiling points relatively close to that of ethyl alcohol and which, considered as a groupnhave a boiling range which is inclusive of the boiling point of ethyl alcohol. Such a crude methanol, therefore, serves very effectively as a denaturant and, as noted, possesses an unexpected top cylinder lubricating value.

In a more desirable embodiment of the invention, a special type of crude methanol is utilized, the purpose of which is to impart to the ultimate fuel a high or optimum degree of top cylinder lubricity. For this purpose, a given quantity of crude methanol may be fractionated to separate and recover the higher boiling alcoholic lubricants. This separated fraction may then be blended with a predetermined quantity of unfractionated crude methanol. The resulting product then comprises a special compound which is characterized by a high degree of top cylinder lubricity as well as a high degree of potential denaturation. Such a product, in a functional sense, differs considerably from crude synthetic methanol.

In making up such special products, the quantity of the higher boiling lubricating fraction, which is added to the crude synthetic methanol, may be varied over a relatively wide range, depending upon the lubricating efiect desired. Effective results are secured by adding to crude synthetic methanol a quantity of such higher boiling fractions which is equivalent to from 1 to 5 or more times as much as normally occurs in the crude product. It will be appreciated, of course, that the quantity of the lubricating fraction which is added to the crude synthetic methanol will be governed to a great extent by the particular percentage of the denaturant concentrate which is to be blended with the fuel. When relatively small amounts of the denaturant are to be added to the alcohol, the percentage of the lubricating fraction in the denaturant is preferably commensurately increased.

As indicated hereinbefore, a broad object of the invention is to produce petroleum oil-alcohol blends which are characterized by a marked chemical stability as well as by a high operative efliciency. Specifically, it is an object of the invention to produce homogeneous gasolinealcohol blends which are stable and non-gum forming and which, as explained, are effective to lubricate the cylinder of the motor in which they are employed. In effecting these objects, special.

types of denaturant concentrates are utilized which, in a word, comprise homogeneous blends of crude wood methanol and crude synthetic methanol or certain selected fraction of these two products. The utilization of such a denaturant, as will be seen, effectively denatures the alcoholic content of the fuel and homogeneously blends this with the gasoline, and likewise serves to inhibit the formation of gums as well as to impart a high lubricity to the fuel.

As explained in copending application Ser. No. 191,115 it has been determined that crude wood methanol is an excellent denaturant for ethyl alcohol intended for blending with gasoline. Such crude wood methanol comprises a mixture of a large number of different specific chemical compounds, many of which, in a blend with alcohol and gasoline, perform certain specific beneficial functions. As explained in such application, certain fractions of crude wood methanol, among other things, contain phenolic bodies of a reducing action which serve effectively as negative oxidation catalysts or gum inhibitors. Similarly, such fractions contain substances like alkyl esters which operate very efiectively as blending agents in an alcohol-gasoline system. Such fractions also contain a number of substances in addition to methanol which act as denaturants. These several functions are intimately correlated with respect to the components of the methanol fraction such that, when such fractions are employed in the manner there described, results are secured which are as beneficial as they areunobvious.

In accordance with the principles of this invention, therefore, special denaturant concentrates are produced which combine in a correlated and beneficial manner the indicated technological advantages of crude wood methanol and crude synthetic methanol. In one embodiment of this phase of the invention, crude wood methanol fractions, of the type described in the copending application, are compounded with crude synthetic methanol. As will be appreciated, the resulting blend includes a wide series of alcohols, the lower ones of which serve very effectively as denaturants, and the higher ones of which impart a top cylinder lubricity to a fuel with which the denaturant is blended. In such a denaturant concentrate, certain components, such for example as the higher alcohols, alkyl esters, and the like, function specifically and advantageously as blending agents and also, by reason of their tendency to form azeotropic mixtures, as eilective denaturants. A denaturant concentrate comprised of predetermined proportions of crude wood methanol and crude synthethic methanol therefore comprises a pcculiarly beneficial addition agent to gasolinealcohol blends.

In another embodiment of this same broad concept, effective denaturant concentrates may be produced by adding to the crude wood methanol fractions, described in the earlier application, the higher alcohols obtained by fractionation from the crude synthetic methanol in a manner described herein. It will be understood that such a composition comprises an intimate or homogeneous blend of intimately and, functionally correlated chemical compounds, the ultimate or composite function of which blend is effectively to denature alcohol, to render alcohol-gasoline blends physically and chemically stable, and to impart to the ultimate gasoline fuel and inherent top cylinder lubricity.

It is to be understood that the respective proportions of the several fractions are variable over a wide permissive range. As pointed out in the copending application, the gum inhibiting effect of the denaturant may be increased markedly by utilizing, in the concentrate, an appreciable percentage of a steam distilled wood tar distillate. Similarly, as will have been appreciated, the percentage of the higher boiling alcoholic lubricating fraction may be varied within substantially any desired limits, since this fraction itself is miscible with the base solution, i. e., the crude methanol. As those skilled in the art will appreciate, the composition of the denaturant concentrate may be modified to adapt it most effectively to the particular fuel which is to be produced.

The denaturant concentrates contemplated herein may be incorporated in the ultimate fuel in any desired manner. For example, they may be added directly to the alcohol which is to be employed in the gasoline fuel. Similarly, these denaturants may be added to gasoline and such gasoline itself used as a denaturant concentrate for the ethyl alcohol. If desired, and as more fully explained in the copending application referred to, these denaturant concentrates, especially those containing crude wood methanol fractions, may be blendedwith alcohol at the alcohol plant and during the process of final concentration of the aqueous alcohol.

It will thus be observed that, operating according to the principles of the present invention, highly efiicient petroleum oil-alcohol fuels may be produced. Such fuels may, under the invention, be denatured with eminently cheap substances, such as crude synthetic methanol or special fractions of crude synthetic methanol alone, or these in combination with selected fractions from crude wood alcohol. These denaturant concentrates, when incorporated in the ulti- T with from 50 to percent of ethyl comprising,

mate fuel, impartunobvious and peculiarly advantageous characteristics to such fuel. It will be understood that, while these major multiple advantages are secured by the utilization of cheap commercial materials, the invention is considered to reside broadly in the concept of the production of an alcohol-oil motor fuel which is characterized by these several correlated techriical advantages.

I claim:

1. A denatured, alcohol-containing motor fuel for internal combustion engines characterized by a high anti-knock value, improved top cylinder lubricity and a substantial freedom from gums comprising, a light hydrocarbon oil fraction containing unsaturated hydrocarbon components which is intimately bended with ethyl alcohol and a denaturant concentrate, such concentrate comprising an intimately blended solution of crude synthetic methanol, crude wood methanol and light wood tar distillate.

2. A denatured, alcohol-containing motor fuel for internal combustion engines characterized by a high anti-knock value, improved top cylinder lubricity and a substantial freedom from gums a light hydrocarbon oil fraction containing unsaturated hydrocarbon components which is intimately blended with ethyl alcohol and a denaturant concentrate, such concentrate comprising a blend of crude wood methanol, the higher boiling alcohols from crude synthetic methanol and a light wood tar distillate.

3. A denatured, alcohol-containing motor fuel for internal combustion engines characterized by a high anti-knock value, improved top cylinder lubricity and a substantial freedom from gums comprising from 50 to 95 percent of a cracked gasoline fraction which is intimately blended with from 50 to 5 percent of ethyl alcohol, said alcohol containing approximately 5 percent of a denaturant concentrate, such concentrate comprising an intimately blended solution of crude synthetic methanol, crude wood methanol and light wood tar distillate.

4. A denatured, alcohol-containing motor fuel for internal combustion engines characterized by a high anti-knock value, improved top cylinder lubricity and a substantial freedom from gums comprising from 50 to 95 percent of a cracked gasoline fraction which is intimately blended alcohol, said alcohol containing approximately 5 percent of a denaturant concentrate, such concentrate comprising a blend of crude wood methanol, the higher boiling alcohols from crude synthetic methanol and a light wood tar distillate.

LEO'M. CHRISTENSEN.