Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G OR C10K; LIQUIFIED PETROLEUM GAS; USE OF ADDITIVES TO FUELS OR FIRES; FIRE-LIGHTERS
  • C10L1/00—Liquid carbonaceous fuels
  • C10L1/10—Liquid carbonaceous fuels containing additives
  • C10L1/14—Organic compounds
  • C10L1/18—Organic compounds containing oxygen
  • C10L1/192—Macromolecular compounds
  • C10L1/195—Macromolecular compounds obtained by reactions involving only carbon-to-carbon unsaturated bonds
  • C10L1/197—Macromolecular compounds obtained by reactions involving only carbon-to-carbon unsaturated bonds derived from monomers containing a carbon-to-carbon unsaturated bond and an acyloxy group of a saturated carboxylic or carbonic acid
  • C10L1/1973—Macromolecular compounds obtained by reactions involving only carbon-to-carbon unsaturated bonds derived from monomers containing a carbon-to-carbon unsaturated bond and an acyloxy group of a saturated carboxylic or carbonic acid mono-carboxylic

Definitions

• This invention relates to improved hydrocarbon compositions -boiling substantially within the gasoline boiling range, particularly such compositions designed to be used as fuels in internal combustion engines.
• Another fuel system mechanism which is particularly prone to malfunctioning due to plugging with ice is the carburetor.
• the carburetor At this point in the fuel system, additional moisture is introduced from the air for combustion. Even though both liquid fuel and air temperatures are above 32 F., the evaporation of the fuel in the carburetor will often cool the system to 32 F. or below, especially soon after starting the engine, whereupon ice will form and will frequently cause the engine to stall because of the blocking of fuel and air passages by the ice.
• hydrocarbon products boiling within the gasoline boiling range besides gasoline itself are susceptible to difiiculties due to the formation of ice therein, for example, mineral spirits, cleaners naphtha, VM&P naphtha and other specialty products such as benzene, toluene and xylenes, isopentane and the like.
• the high water solubility of these compounds makes them susceptible to removal from the hydrocarbon product by the leaching action of the free Water with which the product usually comes in contact during storage.
• water-soluble products when incorporated into the hydrocarbon product, act as solubilizers for water, thus actually increasing the amount of water which the product will absorb during commercial handling.
• the alcohols for example isopropyl alcohol, still are somewhat effective in decreasing the incidence of stalling of automobiles due to carburetor icing.
• a more particular object is to provide such a composition which has improved characteristics with respect to ice formation therein.
• a further object of the invention is to provide a gasoline fuel composition with improved anti-icing characteristics.
• Still further an object of the invention is to provide a hydrocarbon composition with improved characteristics with respect to ice formation therein and which requires neither a water soluble anti-icing additive nor a high concentration of an anti-icing additive.
• the polymeric additive alleviates icing difiiculties is not known. Since the additive is not water soluble, it probably does not act strictly as a freezing point depressant, and so it may not actually prevent the formation of ice when the hydrocarbon product is even if the ice still forms, it is clear that the presence vents, or at least reduces, plugging of screens and interference with the operation of pumps, injector mechanisms, carburetors, and the like.
• the hydrocarbon base material which is the major component of the composition of the invention can be any hydrocarbon or mixture of hydrocarbons boiling substantially within the gasoline boiling range; that is, those with normal boiling points from about 30 F. to about 450 F.
• the invention is particularly directed to mixtures of hydrocarbons within an ASTM boiling range of from about F. to about 425 R, such as gasoline, and especially such as aviation gasoline, which normally has an ASTM boiling range of from about F. to about 350 F.
• the acid from which the vinyl ester is derived can generally be any of the lower molecular weight alkyl carboxylic acids, preferably mono-carboxylic acids, containing up to 5 carbon atoms.
• the vinyl ester can thus be vinyl formate, vinyl acetate, vinyl propionate or the like. Vinyl acetate is a cheap, readily available and especially preferable ester for the purposes of the invention.
• the average molecular weight of the hydrolyzed copolymer be at least 8000 and even better results will be generally obtained with molecular weights above about 10,000.
• molecular weights up to about 100,000 can be used, better results will be generally obtained with average molecular weights no greater than about 50,000, and especially no greater than 25,000.
• the ratio of the number of polar groups to the number of non-polar groups is at least 1: 1, especially at least 3: 1.
• this ratio is preferably not greater than 8:1, 'and especially not greater than 5:1.
• the degree of hydrolysis of the copolymer determines the proportion of the polar groups which will be hydroxyl groups. It is preferred that at least 50%, and especially at least 80%, of the polar groups be bydroxyl groups. Generally, best results will be obtained if nearly all are hydroxyl groups; however, practical considerations in the hydrolysis of the copolymer will usually limit the economic proportion of hydroxyl groups to about 90 or 95% of the total of the hydroxyl and alkanoyloxy groups of the hydrolyzed copolymer.
• the copolymer can be readily prepared by reacting the vinyl ester with the alpha-olefin in the presence of a free radical catalyst or initiator.
• a free radical catalyst or initiator i. e., an oxygencontaining catalyst is preferred, i. e., a compound containing two directly linked oxygen atoms, preferably an organic peroxide, for example, ditertiarybutyl peroxide, benzoyl peroxide or dichlorobenzoyl peroxide, but other free radical catalysts, for example, :,0c-3Z0dilSOblltY1'O- nitrile and the like, have been found to be effective.
• the reaction can be made to progress by the use of actinic radiation, such as ultraviolet light.
• the concentration of the catalyst in the reaction mixture can be varied widely, for example, from as low as 0.01% wt. to wt. or more, based on the weight of the reactants initially added.
• the larger the concentration of catalyst 7 should be at least about 0.1:1 in order to provide a sufiicient ratio of polar to non-polar groups in the copolymer. Best results are obtained if this ratio is at least about 05:1 and especially at least about 1.5:1.
• this ratio should generally be not greater than about 10:1 and best results are obtained if this ratio is not greater than 5:1, especially not greater than 2.521.
• the amounts of excess monomer recovered after the polymerization reaction will, of course, indicate the ratio of the original monomers which have entered the copolymer. Accordingly, the ratio of the number of alkanoyloxy groups to the number of alkyl groups in the copolymer can be adjusted at will by varying the original ratio of the two monomers initially charged to the reaction.
• the temperature of the reacting mixture can be selected for convenience in order to effect a substantial conversion of the monomers into the copolymer in a reasonable length of time. Ordinarily, the reaction will progress satisfactorily at temperatures of from about 50 C. to about 200 0., preferred temperatures being from about 70 C. to about C.
• the reacting pressure should be sufficient to keep the reactants substantially in the liquid phase at the reaction temperature employed. The unreacted monomers and any solvent used can then be distilled off from the copolymer product.
• Either a batch or a continuous process for the polymerization reaction can be used.
• Especially suitable copolymers are obtained when the ratio of the unreacted monomers is kept approximately constant throughout the reaction, as is of course the case in the normal continuous process technique.
• the same advantage can be attained in a batch process by continuous or intermittent addition of further amounts of one of the monomers, usually the ester, to the reacting mixture of monomers and copolymers.
• this copolymer After this copolymer is formed and separated, it must be hydrolyzed to a substantial extent, otherwise it will not be suitable for the purposes of the invention.
• hydrolyzed we mean that a substantial proportion of the alk anoyloxy groups of the copolymer chain must be converted to hydroxy groups. The way this is accomplished is generally not important so long as the resulting hydrolyzed copolymer is not contaminated to any great extent with the other products of the hydrolysis reaction.
• An especially convenient and effective method of effecting the hydrolysis of the copolymer is to react it with a lower molecular weight alcohol, such as methanol or ethanol, in the presence of a small amount of a hydrolysis catalyst such as an alkali metal alkoxide, or alcoholate, for example, sodium methoxide (i. e., sodium methylate), and preferably also in the presence of a solvent, which can be, for example, either an excess of the alcohol or an ester of the alcohol and the acid group of the vinyl ester monomer, or both.
• a hydrolysis catalyst such as an alkali metal alkoxide, or alcoholate, for example, sodium methoxide (i. e., sodium methylate)
• a solvent which can be, for example, either an excess of the alcohol or an ester of the alcohol and the acid group of the vinyl ester monomer, or both.
• the alkali metal alcoholate is neutralized, for example, with an equivalent amount of glacial acetic acid, and the solvent and the hydrolysis products can then be distilled off from the hydrolyzed copolymer.
• Other well known methods of hydrolyzing polyvinyl esters are generally suitable, such as those described in U. S. Patents Nos. 2,266,996; 2,464,290; and 2,668,809. Saponification with aqueous sodium hydroxide is efifective but less desirable because of the necessity of removing from the hydrolyzed copolymer the high concentrations of excess sodium hydroxide and the resulting sodium salt of the acid group of the vinyl ester.
• hydrocarbon compositions of the invention can, and ordinarily will,
• additives such as the usual commercial additives, for example, antidetonants, such as tetraethyl lead, iron carbonyl, dicyclopentadienyl iron, xylidene and N-methyl aniline, lead scavengers, such as ethylene dibromide and ethylene dichloride, dyes, spark plug antifoulants, such as tricresyl phosphate and dimethyl xylyl phosphate, combustion modifiers, such as alkyl boronic acids and lower alkyl phosphates and phosphites, oxidation inhibitors, such as N,Ndisecondarybutyl-phenylenediamine, N-n-butyl-p-aminophenol and 2,6-ditertiarybutyl-4-methylphenol, metal deactivators, such as N,N'-
• disalicylal-1,2-propanediamine and rust inhibitors such as polymerized linoleic acids and N,C-disubstituted imidazolines.
• Freshly distilled vinyl acetate was added to a mixture of straight chain alpha-olefin hydrocarbons containing 4% v. (3131126, 19% V. C14H2s, 4% v. C15H30, 45% v. Ciel-132, 3% V. C1'1H34 and V. C18H36, With the remainder being minor amounts of saturated hydrocarbons in the same carbon number range, in the proportion of 1.9 mols of the acetate per mol of the olefin. To this mixture was added 1% w. benzoyl peroxide as an initiator. The mixture was then stirred at 80 C. for 16 hours. At this time the unreacted material was distilled off to a temperature of 200 C. at 18 mm.
• the remaining copolymer amounted to approximately 61% by weight of the monomers initially charged.
• the copolymer was cooled and analyzed.
• the acetate to olefin mol ratio in the copolymer was 3.95 to l, and the ester value was 0.71 equivalent per 100 grams.
• the copolymer was then hydrolyzed as follows: To 100 parts by weight of the copolymer was added 72 parts of anhydrous mefllyl alcohol, 0.72 part of water and 1 part of sodium methylate. This mixture was heated and maintained at 65 C. with refluxing for 2 hours. The mixture was then cooled and to it was added approximately 10% excess of glacial acetic acid, based on the stoichiometric ratio of acetic acid to the sodium methylate previously added. The excess methanol and the hydrolysis product methyl acetate were distilled off and the hydrolyzed copolymer recovered. The product was analyzed and found to have a hydroxyl value of 0.64 equivalent per 100 grams,
• the copolymer had been about 80% hydrolyzed.
• the product was a clear, light brown, oil
• EXAMPLE H filled with water.
• the waiter thus displaced is introduced into a second glass vessel, initially filled with the hydrocarbon product to be tested.
• the hydrocarbon product thus displaced from the second glass vessel is passed through a heat exchanger, where its temperature is reduced to the desired level, usually between about 0 F. and 20 F., and immediately thereafter through a 10 micron paper filter (Bendix Skinner Division, Bendix Aviation Corporation, Part No. 568,509).
• the flow rate of the hydrocarbon product through the filter was held constant in all tests at 38 cc. per minute.
• the pressure difierential across the filter at any time is therefore a measure of the degree to which the filter is plugged with ice.
• the base product selected for the tests in this example was a specification MIL-F-5572 115/145 grade aviation gasoline, containing only the specification additives, tetraethyl lead, ethylene dibromide and 2,6-ditertiarybutyl-4 methylphenol oxidation inhibitor.
• Additive A listed in Table I, is the hydrolyzed copolymer obtained in Example I.
• Additive B is a C,N-disubstituted imidazoline of the general structural formula:
• compositions of the invention are thus seen to be superior to the usual commercial gasoline by several magnitudes, and that the presence of a corrosion inhibitor does not detract this benefit.
• EXAMPLE I III In order to prove the benefits of the compositions of the invention in commercial equipment, they were tested in a full-scale mock-up of the fuel system of the model 1049C Super Constellation aircraft.
• the equipment and procedure for this test is as follows:
• the fuel to be tested is contained in a well-insulated 1000 gallon tank equipped with internal cooling coils and fuel booster pump.
• a oneinch aluminum fuel line is led into an insulated cold box approximately 20 x 3 x 3 feet which contains all other components of the system.
• the atmosphere within the box is maintained at a low temperature by circulation of carbon dioxide through the box via a fan and duct system.
• the fuel line is feet long and is connected to a 10 micron paper filter which is provided with a by-pass which mate opens a t about 19 cm.
• the base fuel in each test was a specification MIL-F- 5572 115/145 grade aviation gasoline, containing only the specification additives, tetr-aethyl lead, ethylene dibromide and 2,6-ditertia-ry-butyl-4-methylphenol oxidation inhibitor.
• the 1000 gallons of test fuel is first agitated with gallons of water and the air in the space above the fuel is saturated with water for.8 to 12 hours before a test. The water is then drawn off and the fuel is pumped to the 1000 gallon test tank through a 10 micron bronze filter. This treatment saturates the fuel with water at the desired temperature but excludes any entrained separate water.
• the fuel is-then cooled without stirring, to avoid ice crystallization on the cooling coils or the sides of the tank.
• the refrigerant is turned off when the fuel is at the desired test temperature (-10 F. for these tests) to eliminate dehumidification of the fuel by the exposed coils as the fuel is used in the test.
• the fuel is then pumped through the system in the cold box, with the temperature of the carbon diox ide atmosphere therein being set at 40 F., all variables being controlled exactly as in a commercial aircraft under the selected conditions.
• a constant fuel flow is maintained at 1900 pounds per hour by adjustment of the throttle valve on the outlet of the cold box. It has been found that no icing occurs anywhere downstream of the 10 micron filter until it has iced and the bypass is opened.
• a standard ASTM-CFR fuel research engine was fitted with a Chevrolet carburetor (Carter, Model No. WA- 1-4135). Intake air for the engine was adjusted for the tests to a constant temperature and humidity at the air inlet to the carburetor of 41 F. and 75 percent relative humidity, respectively, a combination of atmospheric conditions which is known to lead to carburetor icing very frequently in practice.
• Additive A of Table II is a hydrolyzed vinyl acetate/ l-octadecene prepared with the procedure of Example I except that the ratio of vinyl acetate to l-octadecene charged was 1.6:1, the polymerization reaction was allowed to progress for 24 hours, the yield of copolymer was 40.5%, and the hydrolysis was effected by refluxing the copolymer for 24 hours with parts of 3A denatured alcohol in which 0.25 part of metallic sodium had been dissolved for each parts by weight of copolymer.
• the ratio of polar groups (hydroxyl and acetate) to non-polar groups in the hydrolyzed copolymer was 3.5:1, the hydroxyl value was 0.72 equivalent per 100 grams, the degree of hydrolysis was 85.6% (i. e., 85.6% of the total number of hydroxyl and acetate groups consists of hydroxyl groups), and the molecular weight was about 16,500.
• Additive B of Table II was also a vinyl acetate alpha- 'olefin prepared with the procedure of Example I, but in this case the alpha-olefin was l-dodecene, the ratio of vinyl acetate to l-dodecene charged was 0.835 :1, the polymerization reaction was allowed to progress for 24 hours, the yield of copolymer was 27%, and the hydrolysis was effected by refluxing the copolymer with 400 parts of methanol in which 0.25 part of metallic sodium had been dissolved for each 100 parts by weight of copolymer.
• the ratio of polar groups (hydroxyl and acetate) to non-polar groups in the hydrolyzed copolymer was 2:1, the hydroxyl value was 0.748 equivalent per 100 grams and the degree of hydrolysis was 96% (i. e., 96% of the total number of hydroxyl and acetate groups consists of hydroxyl groups).

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• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
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• Organic Chemistry (AREA)
• Liquid Carbonaceous Fuels (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)

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  • BE BE550520D patent/BE550520A/xx unknown
• 1955
  • 1955-08-24 US US530418A patent/US2800401A/en not_active Expired - Lifetime
• 1956
  • 1956-08-22 DE DEN12634A patent/DE1014785B/de active Pending
  • 1956-08-22 FR FR1157448D patent/FR1157448A/fr not_active Expired

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