US2363516A - Compounded hydrocarbon oils - Google Patents

Description

UNITED STATES PATENT OFFICE COMPOUNDED HYDBQCABBON OILS Bruce B. Farrington and James 0. Clayton,

Berkeley, and Don H. Etaler, Albany, Calif., assignors to Standard Oil Companyof California,

San Francisco, Calif., a corporation of Delaware No Drawing. Application December 3, i942, Serial No. 467,780

5 Claims.

This invention relates to new and useful compositions of matter and to methods of preparing the same. In particular, it relates to compositions comprising hydrocarbons of the lubricating oil class, in major part, in which are dissolved 'or suspended minor amounts of certain metal salts of organic aliphatic carboxylic acids, either alone or in admixture with other compounding agents of the same or different type.

This application is a continuation-in-part of our copending application Serial No. 322,946, filed March 8, 1940, now Patent No. 2,349,817.

It has long been the desire of the lubricating oil compounding art to obtain an oil, particularly of petroleum origin, which alone or with the addition of relatively small amounts of compounding agents, would resist deterioration or degradation when subjected for long periodsof time to high temperatures and pressures, in the presence of metals, air or oxygen, or hydrocarbon partial combustion products. Deterioration of the character referred to here manifests itself in diverse efiects, dependent upon the nature and degree of refinement of the hydrocarbon oil and upon the environment to which it is subjected, but reference may be made to Diesel engine piston ring sticking, in which the exposure of a lubricating oil to such temperatures as 425-650 F., in the presence of oxidizing combustion gases at pressures as high as 7501150 lbs/sq. in., causes the deposition of oil degradation prodnets of such a. cementitious character as to effectively take piston rings out of service; to the deposition of sludge from automobile crankcase oils, apparently as the result of oxidation and/or polymerization phenomena; and to the corrosion of metal bearing surfaces, apparently as a result of phenomena which cause the formation of organic acidic products. This situation is aggravated by the fact that improvements in the mechanical arts have brought about increasing severity in the conditions to which hydrocarbon oils are subjected, and by the fact thatoil compounding designed to effect a stability in one direction often brings about a marked instability in another. '1

It has been found that the addition to a lub eating oil of small amounts of a metal salt of an aliphatic polycarboxylic corresponding to the formula- H (CHz),.COM

R1 (ohm-000R, in which n and m are zero or whole numbers,

M is a metal, including the hydrogen equivalent of a polyvalent metal, R1 is an oil-solubilizing group of essentiallyhydrocarbon structure containing at least 10 carbon atoms, and R: is hy- 5 drogen, a metal or other basic radical or an organic group, brings about an improved stability in hydrocarbon oils when the same are sub- Jected to high temperatures and/or pressures in the presence of oxygen and metals. One or more of the hydrogens of the indicated methylene groups and of the group used in the polar substitution just referred to are as follows:

Name Formula CH=CH all arbamyl -C0 (NHz) Alkyl or aryl thiolcarbox 0 S R Alkyl or aryl thionocarboxyL. -C S 0 R Mercapto SH Alkyl or arylthio. S R

hiono Dithio -S S- Sulflnyl =8 0 Sulfonyl -S O: Tminn H Alkamino or arylamino -NHR gialksmino or diarylamino ---NR,

10 g g a y szono Triazen Trinm Pynnn socyano C 0 CN Afiyl or sryl sulflno S 01R Alkyl or cry] sulio -S 0|R Alkyl or 1 sulfamino NHS on:

Name Formula Sulfamyl Sulfonamido- Selenyl S e Alkyl or aryl selenyl. S all e] =8 e 8 e =S e0: S e0 (0 R) S e0:( 0 R) --S eCN TeH TeR Te R): PO (0 R) 1 0R Alkyl or aryl phosphinate =P0 O R Phosphate PN- Phosphoro PP- Phosphmm PAs- Arsino ASH: or =AsH Arsenoso AsO rso. AsO: Alkyl or aryl arsenate OAsO (O R); Alkyl or aryl arsenite. 0 AsEOR): Alkyl or aryl arsono AsO 0R); Alkyl or aryl arsinico. AsOOR Isocyanate NC 0 Thiocyanate 8 CN Isothiocyanate... S NC Nitroso NO Nitro.-. NOz Isonitroso.-. =NOH Hydroxemin NHOH Azoxy NO Isonitro NO 01:! Phosphino PH, or =PH Phosphoroso P hospho I Alky or aryl phosphate. OPO (0 R): Alkyl or aryl phosphite. 0P(OR): Silicyl iHa Silicylene S iH1 Alkyl or aryl silicono S i0 0 R rseno.-. sAs- Stibino. S bHz or =8 bH Stiboso. Stibo S b0: Alkyl or arylantimonate 0 S b0 (0 R) Alkyl or aryl stibono S b0 (0R): Alkyl or aryl stibinloo =S bOOR Antlmono SbS b- Stibarseno.--- S bAs- Bismuthino- BiH; or =BlH Boryl. 0 Alkyl or aryl borate OB (0R): Alkyl or aryl silicate O Si(O R): Iodoso. 0 Stannyl SnHa Iodoxy IO;

The metals whose substituted carboxylic acid salts are useful for the purposes of the inventionmay have valences from one to four, inclusive, and the salts of potassium, calcium, magnesium, aluminum, chromium, cobalt, lead, manganese, tin and zinchave been found of particular utility.

Among the aliphatic polycarboxylic acids whose metal salts are suitable in the practice of the invention are the alpha-alkyl and alphaalkenyl malonic acids represented by the formula coon R-OH

coon

in which R represents an alkyl (CnHZn-i-l) or alkenyl (CnHZn-l, CnH2n-3, etc.) group of ten or more carbon atoms; the alpha-alkyl and alpha- I alkenyl succinic acids- R-CH-COOH Hz-COOH in which R has the same significance as in the above formula for alkyl and alkenyl malonic acids; and the analogous alpha-, betaand gamma-alkyl and alkenyl glutaric, adipic, pimelic, suberic, maleic, fumaric and tricarballylic acids.

Specifically, acid and normal salts and salts of partial esters of the following acids may be used in accordance with the invention: alpha-cetylmalonic acid, alpha-cetenylsuccinic acid, alphaeicosenylsuccinic acid, and alpha-eicosyl tartaric acid, these acids having the following structurescoon CltHuC-H coon Alpha cetylmalonic acid clin-cH=cn-cH-coon m-coon Alpha cetenylsuccinic acid CuHa1-CH=CIiCH-C0Oll cut-coon Alpha eicosenylsuccinic acid coon n-c-on uBm-ClirCHz-(E-QH Y coon Alpha eicosyltartaric acid For the purposes of the invention, these or other acids are converted into metal salts, preferably polyvalent metal salts. One manner of so doing comprises forming an aqueous or alcohol-water solution or suspension of an alkali metal salt of the acid and adding to this solution or suspension a water soluble salt of the desired polyvalent metal, e. g. calcium chloride, thereby precipitating the desired poly-valent metal salt. The acid salt or the normal salt may be formed, or one or more but not all of the free carboxyl groups may be esterified and the metal saltof the partial ester formed. Normal salts, acid salts and salts of partial esters thus formed are used in hydrocarbon oil in accordance with the invention.

With further reference to the structure and mode of preparation of the salts of the invention, we have found that malonic acid and succinic acid salts corresponding to the formulae R1-CH-CO0M CHr-COOM R -C and I or GH -COO R Iii-C H-COOR: 000 R1 Malouates Succinatcs wherein M is a metal, R1 is a C10 or higher oilsolubilizing group and R2 is hydrogen, a metal or other basic (salt-forming) radical, or an organic group, are especially valuable lubricant additives and that the malonates more particularly are desirable lubricant additives and the like. These salts may be exemplified by calcium alpha-cetylmalonate, calcium alpha-cetenylsuccinate, calcium alpha-eicosenylsuccinate and calcium alphaeicosyl tartrate, the cetyl, centenyl, eicosenyl and eicosyl groups typifying the oil-sulubilizing group R1 and calcium typifying the metal M as well as the radical R2. (The designation alpha with regard to malonic and succinic acids substituted on a methylene carbon atom by an alkyl or alkenyl group is used throughout to avoid confusion with the alkyl and alkenyl esters of the same acids, wherein the alkyl or alkenyl group is present in a carboxy ester group COOR. These esters are often referred to as alkyl and alkenyl malonic acid and succinic acid, and their salts as metal alkyl (or alkenyl) malonates and succinates.) Detailed examples of the preparation of these salts are given below:

The alpha-alkyl malonates ethylate (prepared by dissolving 12 grams of metallic sodium 'in 100 cc. of absolute ethyl alcohol). Sodium diethyl malonate is precipitated from solution. It is recovered by filtration and diethyl alpha-cetylmalonate is formed by adding to the precipitate or sodium diethyl malonate 190 grams of cetyl iodide and maintaining the reaction mixture at 212 1". Sodium iodide is removed from the product by washing with water. The diethyl alpha-cetylmalonate is hydrolyzed by heating at 212 1''. for 24 hours with 520 cc. of aqueous potassium hydroxide solution. The resulting potassium salt is salted out by adding potassium chloride to the aqueous solution. Excess cetyl iodide is removed from the potassium salt by extraction with ether. The potassium salt oi alpha-cetylmalonic acid is then suspended in a 50-50 alcohol-water solution and heated to 190 F. and an excess of aqueous calcium chloride solution is added. Calcium alpha-cetylmalonate is thus precipitated and is washed with water and dried.

The reactions involved in this preparation are as follows:

Na-C

COOCzHs +Nal C O 0 Cali;

Production oi diethyi alpha-cetylmalonato CnHu-CH +2KOH GOOCQHI CmHu-C COOK olefin-CH +2CsH|0H C 0 O K Hydrolysis oi dicthyl alpha-cetylmalonate COOK CisHas-CH C 0 O K C 0 0 C im-C Ca+2KCl Production of calcium alpha-cetylmalonatc The alpha-allcylene succinates One molecular proportion of maleic anhydrlde and 1.25 molecular proportions of olefin polymer, such as an olefinic mixture having an average carbon content of C14, C18 or C20 produced by polymerization of petroleum refinery olefins, are reacted in an iron pressure vessel, without agitation, at 400 -450 F. for 4 to 6 hours. The product. an alkenyl succinic anhydride, is distilled under vacuum to remove unreacted polymers and maleic anhydride, the theoretical quantity of water is added to hydrolyze the anhydride, and .he water-alkenyl succinic anhydride-mixture is digested under reflux for 1 hour at 195? E, thus forming the alpha-alkenyl succinic acid. A slight excess of aqueous KOH solution is added and the mixture is heated at 180 1!. for $5 hour, thus forming the di-potasslum salt of the alkenyl succinic acid. The calcium salt is formed by adding to the aqueous solution oi potassium salt as obtained above an equivalent amount of 10% aqueous CaClz solution. The precipitate of nor- Jmal calcium salt is filtered, washed free of impurities with water. and dried. The reactions involved may be represented as follows:

R-CH=CH-CH.OOOH 0 H10 ---0 Hs.COOH

ECO

Production of alpha-alkonyl succinic acid RCH=CH--GH.COOK

Hz. 0 0 O K Production oi dipotassium alphs-alkenyl succinate CaClg mooox R-CH=CH-CH.COO

Us 2K0] moo o 7 Production oi calcium alpha-alkenyl succinate Note.--It is assumedthat the olefin, which is represented as a primary olefin but which may be a secondary or tertiary. olefin, adds on to maleic anhydride in the manner indicated, but it may add on in such a way as to leave intact the unsaturated bond ofthe maleic anhydride. Thus the final product,.though called an alkenyl succinate, may -be instead an alkyl maleate.

The preparation of calcium alpha cetylmalonate as given above is the familiar malonic ester synthesis (Cf. Liebigs Annalen der Chemie, vol. 204, page 121). This synthesis, based upon the reactivity of the methylene hydrogens of malonic ester (diethyl malonate), is customarily used in l the synthesis of monocarboxylic aliphatic acids, since the corresponding free alpha alkyl malonlc acid (produced by hydrolyzingthe alpha alkyl malonic ester) is readily converted onheating, by 1 loss of CO2, into a monocarboxylic acid. For purposes of the present invention, however, the sodium derivative of malonic ester is condensed with a C10 or higher alkyl halide or the like (or a technical mixture of halides averaging'cwjor higher) and the resulting alpha alkyl rrialonic ester is converted to a metal salt in the manner shown above. Among the advantages we have found in this application of the malonic ester synthesis, there may be mentioned the fact that from cheap materials (such as malonic ester, sodium and the higher alkyl halides) there'is easily prepared an oil-soluble salt of a polycarboxylic aliphatic acid, and, as shown in more detail below, such salts are exceedingly potent improvement jagents for hydrocarbon oils.

smo

The preparation of the calcium alpha-alkenyl succinate as given above is based upon the Diels' condensation reaction with the olefin, in which cant to deteriorate with gum formation and piston ring sticking: operation was at 1600 revolutions per minute: engine Jacket temperature was maintained at 375 F.; crankcase oil temperature was maintained at 220 F.; at periods 01 hours the operations were interrupted and the condition of the piston rings determined. In Table I, the base oil referred to as Western was an acid-refined lube stock of California origin; A. P. I. gravity 21.4; viscosities at 100 and 210, 622 seconds and 56.6 seconds, respectively, Saybolt Universal. To this base oil were added the various salts in the amounts indicated, by weight.

Tssu: I

Prevention or postponement of piston ring sticking Hours to cause Relative rin ring sticking Western 30 +0.68% calcium a-Qlcflsyltflltrflt. +0.60% calcium a-cetylmalonate.

+0.34% calcium a-eicosenylsuccinate Poor. Good. Poor.

. D0. Fair.

Very good.

Fair.

None: A plus sign following a stated number of hours in the ante the stated hours duration.

reaction a hydrogen of the olefin migrates to one methine group of the maleic anhydride and the olefin residue attaches itself to the remaining methine group. However, as stated, the mechanism of the reaction and the nature of the final product may be different from that depicted above.

The salt additives of the invention, as stated, comprise at least two aliphatic carboxylate groups, at least one of which is in the form of a metal carboxylate group, and a C10 or higher oil-solubilizing group. The oil-solubilizing group may be substituted provided the substituent or substituents do not greatly inhibit its oil-solubilizing capacity, and while long chain alkyl and alkenyl groups are preferred, the higher alkaryl, aralkyl, aryl and cycloaliphatic groups may be used. Polyvalent metals are preferred in forming the salts of the invention, and the same atom of polyvalent metal may neutralize two or more aliphatic carboxylate groups of the polycarboxylic acid. However, the one or more carboxylate groups in addition to the essential metal carboxylate group may, as stated, he a free carboxyl group, or may be neutralized by ammonia or an amineor may be esterified.

The following specific examples will serve to illustrate the practice'and the advantages of the invention:

. EXAMPLES, SET I Among the beneficial effects which flow from the incorporation of a metal salt or a mixture of metal salts of the above described aliphatic acids in a hydrocarbon oil of the lubricating oil classis the prevention of piston ring sticking, or its marked postponement, under very severe motor conditions, as for example in Diesel engine or in aircraft spark or compression ignition engine operations.

In the tests whose results are summarized in Table I, a single cylinder Lauson gasoline sparkignition engine, 2% inch bore and 2 inch stroke, loaded with fan dynamometers, was operated under extremely severe conditions, designed to develop fully the tendency of the crankcase lubripenultimate column indicates free rings at the conclusion of a test of EXAMPLES, SET II Among the further benefits to be derived from the addition of the metal salts of the invention to hydrocarbon lubricating oils is a decreased corrosivity toward bearing metals, particularly those of the cadmium-silver and copper-lead types. This diminution in corrosivity is particularly marked upon the incorporation in the hydrocarbon oils of metal salts of those aliphatic carboxylic acids corresponding to the type R2OOC(CH2) mCH(R1)-(CH2) 1.COOH in which a polar group or radical as above exemplified is substituted for a hydrogen atom attached to a carbon atom in close proximity to the carbon atom of a salt-forming carboxylic acidpreferably in the alpha position, less preferably in the beta position and of decreasing desirability and effectiveness in the gamma, delta, epsilon, etc., positions, in the order named.

In the tests whose results are summarized in Table II, thin sheets of the indicated bearing metals were cut into strips (copper-lead, 1' x 1%" x cadmium-silver,

and these strips were immersed in the exemplifled oils carried in 2" x 20" glass test tubes;

the oils, washed with petroleum ether and carefully wiped with a soft cotton cloth; weight losses of the strips were measured in connection with the weight of each individual strip. The duration of the tests was '72 hours, and the weight losses tabulated below are those found at the end of the 72-hour period; the losses-reported, however, represent the averages of at least two and sometimes more duplicate or check corrosion tests under these conditions. In connection with the results reported in Table Ii, attention is directed to those oils compounded by the addition of agents other than those of the invention (oils A, B, C, etc.), in which the compounding, while perhaps of benefit in respect to some property .01 the oil, is of definitely deleterious effect in respect to the corrosivity of the oil toward bearing metals. Attention is additionallydirected to the compounded oils of Example No. 42 to which has been added, as a further compounding agent, calcium cetylphenate, wherein it appears that the increased corrosivity due to the original compounding has been prevented or inhibited by the agents of the invention.

TABLE II Reduction of corrosivitu to bearing metals i ht loss mgma, Example 011 Ou-Pb Cd-Ag Western 30.....--.... 13.9 0.4 +0.63% calcium a-elcosyltartrate. 5.0 0.9 +0.50%, calcium s-cetylmalonate. 0. 8 0. 3 0 calcium a-cetenylsueein- 1.1 0.3

a +0 34% calcium a-eicosenylsuc- 1.6 0.1

c na .e. +0.507 calcium cotylphenate+ 40.7 0.0

0.50 a calcium a-eicosenylsuccinate. +0.50% calcium stearate 131. 9 180. +1.0% aluminum dina hthenateu 67 113 +l.0% magnesium nap theuate--. 139 119 +1. 0% calcium cctylphenate 120 12. 1

[ EXAMPLES, sET In A still further benefit to be derived from the addition of the metal salts of the invention to hydrocarbon oils, particularly noticeable in the case or salts of those acids carrying polar substituents as described, is a marked lessening of color instability upon exposure of the oils of the invention to heat, in the absence of air or metals.

In the tests whose results are summarized in Table III, samples of the exemplified oils were held, in glass, at 300 F..for 6 hours. The oils were cooled at the end of this period of time and their colors measured, for comparison with the uncompounded base oil stocks; A. S. T. M. colors, Method D15534T, were recorded in all cases.

TABLE III Color stability Color Color Examoil am:

heating crease Wester 30............ 3341). a 10... +0.63? calcium a-eicosyltartrate- 4- 1- 17 +0.34 calcium a-eicosenylsuccinato- 4- 34 24".-. +0.18 4 calcium a-cetenylsuccinato-. 4- 1- 2c +0.50} potassium a-cetylmalonate." 4 .4 1% 41.-. +0.50 0 calclum cet1'lphenate+0.10% 6 1% calcium a-cetenylsuccinate. 42. +0.50% calcium cetylphenate+0.50% 7 234+ calcium a-eicosenylsuccinate. 53".-. +0.25 calcium cetylphosphate+ 4 54 0.10 calcium a-cetonylsuccinatc. 64 +0.25 calcium cetylphosphate+ 4- 1- 0.50 calcium a-eicosenylsuccinate. 03. +0.50 0 calcium cetyl henatc+0.25% 5- 34 ciilc um cettylplhosp at+0.20% cale um e470 ny succma e. 64.- +0.50 0 calcium cetylhenate+0.25% 7 236 calc um oetylphosp ate+0.50% calcium a-elcoscnylsuccinate. 71. +10% diisoamyl tartrate+0.10% cal- 4% 1 clum a-cctenylsuccinate. 72. +1.0% dilsoamyl tartratc+0.50% cal- 3% $5 cium a-elcosenylsuccinate.

EXAMPLES, SET IV In many cases still further benefits may be derived from the incorporation of the metal salts of the invention to hydrocarbon oils, by reason of an enhanced "oiliness and/or an increased load carrying capacity of the oils so compounded. In the tests whose results are summarized in Table IV, the figures reported under Weeks wear" are those obtained in the operation of a Weeks wear testing machine, in which a /g inch steel ball is pressed against a 1% inch steel cylinder which is rotated at 600 revolutions per minute and which dips into the 011 being tested; the duration of the test is 16 hours and the body of oil is held at 300 F.; the results are reported in inches of wear X 10, as measured on. the cylinder. The figures reported under Film strength are those obtained in the operation of a Timken machine as described in the B. A. E. Journal, volume 28, page 53, 1928; the results are reported in pounds at failure.

Tum: IV

Wear resistance and film strength EXAMPLES, SET v Still further, the capability of hydrocarbon oils to absorb oxygen, when exposed thereto at superatmospheric temperatures and pressures, is in many cases reduced or postponed by the incorporation in the oils of the metal salts of the invention, particularly those carrying a polar group of the character and in the position referred to repeatedly hereinabove.

In the tests whose results are reported in TableV, the oils referred to were subjected to the oxidator test" particularly described in the Journal of Industrial and Engineering Chemistry, volume 28, page 26, 1936, at 340 F., which conditions may be noted as extremely severe. The results of the tests are reported in cubic centimeters of oxygen absorbed per grams of the respective oils, at the periods of time indicated;

properties of hydrocarbon oils are obtained by the incorporation of as little as 0.1% of the agents of. the invention, but amounts between about 0.2% and 2.0% of the agents, by weight based on the oil, are preferable, dependent upon the degree of inherent tendency toward degradation of the oil itself or as otherwise compounded; amounts higher than about 5.0% are regarded as unnecessary in the best practice of the invention.

A feature of the invention is in the preparation and distribution of bases or concentrates containing relatively large proportions of the additive agents in admixture with hydrocarbon oils of the lubricating or less viscous types or, it more suitable in conjunction with certain of the agents, by reason of solubility relationships or the like, in admixture with aromatic hydrocarbons or with alcohols, esters, ketones or ethers, generall of the aliphatic series. Admlxtures of the agents and lubricating oils or other solvents or carriers containing upward of 50% 01' the essential agents, by weight, may be thus prepared and distributed, for later blending with the particular lubricating oil media desired to be put to use, as occasion demands. In the preparation of either the finished oils of the invention or the bases or concentrates referred to, complete or clear and homogeneous solution is not always necessary: blending agents or homogenizers may be employed ii desirable, to prevent sedimentation of the more oil-insoluble of the agents, but it has been found the possible detrimental eflect oi the presence of filterable insoluble materials of this character, it indeed present, is determined largely by the particular conditions attending the contemplated use, and that their presence is not in all cases deleterious to the functioning or the compositions in their intended manner.

While the character of the invention has been given in detail and numerous illustrative examples of the preparation and utility oi the compositions of the invention have been described, this has been done largely by way of illustrationand with the intention that no limitation should be imposed upon the invention thereby. It will be obvious to those skilled in the art that numerous modifications and variations of the above illustrative examples may be efiected in the practice of the invention, which is intended to be of the of a metal salt of an alkylated phenol, and a small amount, sufficient to inhibit said deterioration and deposition and to inhibit the tendency of said salt of phenol to corrode alloy bearings of the copper-lead and cadmium-silver types, of a metal salt 01' an aliphatic polycarboxylic acid having as a substituent on an aliphatic carbon atom other than the carbon atom of a carboxyl group, an oil-solubilizing essentially hydrocarbon group of not less than 10 carbon atoms.

2. The oil 01 claim 1, wherein said metal salts are polyvalent metal salts.

3. A liquid hydrocarbon lubricating oil normally tending to deteriorate and to form carbonaceous deposits on pistons at temperatures encountered in the operation of internal combustion engines, containing a small amount, sumcient to inhibit said deterioration and deposition, of an oil-soluble polyvalent metal salt of an alkylated phenol and about 0.1 to 5% by weight based on finished oil of a polyvalent metal salt of an alpha alkyl substituted malonic acid wherein the alpha alkyl substituent contains not less than 10 carbon atoms.

4. A liquid hydrocarbon lubricating oil normally tending to deteriorate and to form carbonaceous deposits on pistons at temperatures encountered in the operation of internal combustion engines, containing a small amount, sufllcient to inhibit said deterioration and deposition, of an oil-soluble polyvalent metal salt of an alkylated phenol and about 0.1 to 5% by weight based on finished oil of a polyvalent metal salt of an alpha alkaryl substituted malonic acid wherein the alpha alkaryl substituent contains not 1e than 10 carbon atoms.

5.,A liquid hydrocarbon lubricating 011 normally tending to deteriorate and to form carbonaceous deposits on pistons at temperatures en-v countered in the operation of internal combustion engines, containing a small amount, sum- 7 cient to inhibit said deterioration and deposition,

of an oil-soluble polyvalent metal salt of an alkylated phenol and about 0.1 to 5% by weight based on finished oil of a polyvalent metal salt of the product of condensing malelc anhydride with a (he or higher olefin to produce an alpha substituted maleic anhydride.

BRUCE B. FARRINGTON. JAMES O. CLAYTON. DORR H. E'IZLER...