2,794,720 United States Patent Office Patented June 4, 1957 2 compression engines. However, because of the trend in the automotive industry of utilizing high compression 2,794,720 engines in passenger cars and trucks, the accumulation of deposits results in a number of relatively serious prob FUEL ANTKNOCK lems, including increased detonation, deposit-induced John D. Bartleson, Frankin, Mich., assignor to Ettay autoignition or wild ping, spark plug fouling, reduction Corporation, New York, N.Y., a corporation of Dela in exhaust valve life, and the like. Ware Of the problems previously enumerated, those of wild No Drawing. Application August 13, 1953, ping, spark plug fouling, and reduced exhaust valve life 10 are of considerable concern to the automotive industry. Serial No. 374,154 This results from the fact that each time the lead con 8 Claims. (C. 44-69) centration in the fuel is raised to coincide with increases in compression ratio to eliminate detonation, the magni tude of one or more of these problems generally in This invention relates to the improvement of organo 5 creases. As a result, there is a paramount need existing lead material, and in particular to adjuvants for tetra for a new and improved method for altering the physical ethylead and tetraethylead-containing compositions. and chemical characteristics of deposits and for modi Organolead compounds such as tetraphenylead, tetra fying the combustion process such that the well-known methyllead, tetraethyllead, dimethyldiethyllead, and the detrimental effects of the previously described deposit like have long been known as antiknock agents for fuel 20 induced engine phenomena can be markedly suppressed for spark ignition type internal combustion engines. Of or be eliminated. such materials, however, only tetraethylead has attained It is, therefore, an object of this invention to provide commercial success because of its efficacious attributes. adjuvants for organolead compounds. It is likewise an Likewise, it has long been known that the effective utiliza object of this invention to provide means of improving tion of such antiknock agents is enhanced by providing 25 compositions such as antiknock fluids and fuels which antiknock fluids which consist of organic halogen com contain organolead antiknock agents. Similarly, the pro pounds in admixture with an organolead compound. vision of improved organolead compositions is another Organolead compounds suffer one disadvantage, par object of this invention. A particular object of this ticularly during storage, handling, and blending opera invention is to provide improved tetraethylead-contain tions, namely, their inherent instability. Thus, tetra 30 ing fuels, especially those for use in spark ignition type ethylead and related compounds are susceptible of de internal combustion engines. In addition, an object of terioration which is largely dependent upon the nature this invention is to provide methods of improving anti of the environment. For example, it has been found that knock fluids such that during compounding, storage, and organolead antiknock agents and antiknock fluids con blending operations Such materials are stabilized against taining the same, when in contact with certain metals, 35 the adverse effects of deteriorative environments. An ad such as copper and copper-containing alloys, tend to de ditional object of the instant invention is to provide means teriorate, even in a reducing atmosphere. Such deterio of obviating deposit-induced phenomena of the character ration is postulated to result from an adverse catalytic described hereinbefore. Other important objects of this activity exhibited by such metals. In other words, it is invention will be apparent from the discussion here generally believed that copper and like metals act as 40 inafter. self-perpetuating decomposition accelerators. Another It has now been found that the above and other condition enhancing the deterioration of such antiknock objects of this invention are attained by providing com agents is contact with air. It is generally believed that positions of matter adapted for use as additives to fuel atmospheric constituents, notably oxygen and ozone, tend for spark-fired internal combustion engines comprising to oxidize one or more of the lead-to-carbon bonds with 45 an organolead antiknock agent, and in quantity suffi the formation of insoluble decomposition products. Under cient to stabilize or improve said agent, a metallic deriva these conditions there contemporaneously occurs a color tive of a product obtained by reaction between a phos change in the dyestuff normally present in antiknock fluids phorus Sulfide and an organic compound in which at Such that the visual identification of the product fre least one carbon atom is substituted with at least one quently becomes difficult, if not impossible. Organolead SO univalent radical composed solely of a group VI-B ele antiknock agents are likewise decomposed on exposure ment and hydrogen. Such organic compounds can be to strong light, particularly sunlight. In this case the aliphatic, alicyclic, or aromatic so long as they con decomposition is attributed to the catalytic decomposition tain at least one univalent radical selected from the of the organolead compounds by ultra-violet light. It group consisting of hydroxyl, sulfhydryl, selenohydryl, is apparent, therefore, that the exposure of tetraethyl 55 and tellurohydryl. in other words, the organic com lead and tetarethylead-containing compositions to any pounds used to form the intermediate from which my or all of the above environments results in a number of organolead adjuvants are prepared consist of such com operational difficulties, including loss of antiknock effec pounds as alcohols, mercaptains, seleno alcohols, telluro tiveness, the formation of sludge and other types of alcohols, phenol, thiophenols, seleno phenols, and telluro sediment, and the like. phenols as well as compounds containing mixtures of When organolead-containing compositions are utilized the Several group VI-B containing functional radicals in internal combustion engines, other difficulties are fre as defined hereinabove. For the sake of conciseness such quently encountered. For example, in spite of the high materials are termed hereinafter as the organic reactants. degree of efficiency of the normal scavenger complement It will be apparent that the organclead adjuvants of in antiknock fluids, the accumulation of engine deposits 65 this invention are most readily prepared in two steps. The in the engine cannot be entirely prevented. Such dep first Step consists of preparing a product of a phosphorus osition is particularly prevalent when spark ignition en Sulfide and an organic reactant of the type described gines are operated under conditions of low speed and light hereinbefore. Depending upon the nature of the mate load such as encountered in metropolitan driving con rials employed as well as the reaction conditions, the ditions. As a result of notable improvements in fuel 70 product of this reaction can be used in toto for the prepara antiknock quality which have been made in recent years, tion of my metallic derivatives, or it can be subjected to such deposits present but a few minor problems in low intermediate treatment, as will become apparent from the 2,794,720 3 4 discussion hereinafter. The second step in the prepara The aromatic organic reactants comprise phenols, thio tion of my adjuvants consists of reacting a salt of the phenols, seleno phenols and telluro phenols. desired metal with the above intermediate material. The phenols utilized to prepare the adjuvant intermedi The organic reactant used to prepare the reaction prod ates of this invention can be monohydric phenols, or ucts used as intermediates in the preparation of my ad polyhydric phenols. In the former group I prefer to juvants can be a monohydric or polyhydric alcohol. utilize such phenols as the diverse monohydroxy-substi Typical alcohols so used are exemplified by the alkyl tuted benzenes, naphthalenes, hydronaphthalenes, and the alcohols, alkenyl alcohols, alkynll alcohols, cycloalkyl like, as well as suitably substituted derivatives thereof. alcohols and cycloalkenyl alcohols. In other words, I Thus, in preparing my adjuvant intermediates I utilize can prepare the intermediate products for the prepara 0. such phenols as phencl, ortho-, meta-, and para-cresols, tion of my adjuvants from any of the monohydric or xylols, such as 1,2-dimethyl-3-hydroxy benzene, 1,2- polyhydric alcohols known in the art as aliphatic or diethyl-4-hydroxy benzene, 1,3-dimethyl-2-hydroxy ben alicyclic alcohols. More specifically, the alkyl alcohols, Zene, 1,3-dipropyl-4-hydroxy benzene, 1,3-diisopropyl-5- which preferably should contain from 1 to about 20 carbon hydroxy benzene, 1,4-dimethyl-2-hydroxy benzene, thy atoms, are illustrated by a methanol, ethanol, propanol, 5 mol, carvacrol, mesitol and the like. The latter class of isopropanol, and likewise the various straight and phenols which are used as the reaction products for the branched chain alkyl alcohols exemplified by the several preparation of my adjuvant intermediates, that is, the butyl, amyl, hexyl, heptyl, octyl, and like alcohols up to polyhydric phenols, is illustrated by such materials as and including about eicosyl. Similarly, recourse can be pyrocatechol, resorcinol, hydroquinone, orcinol, hydroxy made to comparable glycols, such as ethylene glycol, 20 hydroquinone, phloroglucinol, butylphloroglucinol, propylene glycol, butylene glycol, and the like, as well as 1,2,3,4-tetrahydroxy benzene, 1,2,3,5-tetrahydroxy ben related materials which are tri- or tetra-substituted zene, 1,2,4,5-tetrahydroxy benzene, pentahydroxy ben hydroxyl-containing organic reactants. The alkenyl alco zene, hexahydroxy benzene, 1,4-dihydroxy anthracene, hols are typified by such substances as allyl alcohol, crotyl 2,6-dihydroxy anthracene, 4,5,9-trihydroxy anthracene, alcohol and similar substances which contain at least one 25 and the like. carbon-to-carbon double bond in the organic residue. Thiophenols are substantially analogous to phenols. In this embodiment it is preferable to utilize alkenyl Therefore, thiophenols corresponding to the phenols of alcohols containing from 3 to about 20 carbon atoms. the character described hereinbefore can likewise be The alkynll alcohols which can be used in preparing the utilized as the intermediate products for the preparation intermediate products for the preparation of my adju 30 of my adjuvants. It will thus be apparent that both vants of this invention are illustrated by such materials mono- and polythiophenols can be utilized in this manner. as propynol, butynol, butyndiol, pentyndiol, and the like Typical mono functional thiophenols include such mate in which the straight or branched carbon chain contain rials as the mono sulfhydryl-substituted benzenes, naph ing at least one acetylenic linkage contains from 3 to thalenes, hydronaphthalenes, and the like, as well as suit about 20 carbon atoms. Such compounds as cyclohex 35 ably substituted derivatives thereof. More specifically, anol, methylcyclohexanol, diethylcyclohexanol, ox-hy such materials are exemplified by thiophenol, o-methyl droxy-2,3,4,5,6,7,8-heptahydronaphthalene, (3-hydroxy thiophenol, m-methylthicphenol, p-methylthiophenol, 1,3,4,5,6,7,8-heptahydronaphthalene, and analogous ma 1,2-dimethylthiophenol, 1,3-dipropyl thiophenol, 1,4-di terials are illustrative of cycloalkyl alcohols; that is, alco isopropyl thiophenol, 1,3-dimethyl thiophenol, 1-methyl hols in which a cycloalkyl nucleus is substituted with at 40 4-ethyl thiophenol, and the sulfur analogues of thymol. least one hydroxyl function. In general, such materials carvacrol, mesitol, and the like. The poly functional should preferably contain from 6 to about 30 carbon thiophenols are typified by 1,2-benzene dithiol; 1,3-ben atoms in the molecule. Typical cycloalkenyl alcohols in zene dithiol; 1,4-benzene dithiol: 1-methyl-3,5-benzene clude the several cyclohexenols, cyclohexenediols, and dithiol; 1,2,4-benzene trithiol: 1,3,5-benzene trithiol; like materials which preferably contain from 5 to about 45 1,2,3,4-benzene tetrathiol; 1,2,3,5-benzene tetrathiol; 30 carbon atoms in the molecule. 1,2,4,5-benzene tetrathiol; benzene pentathiol; benzene It will be apparent to one skilled in the art that thiols, hexathiol: 1,4-naphthalene dithiol, and the like. frequently termed mercaptains, are substantially analogous The aromatic organic reactants parallel the aliphatic to alcohols. Consequently, in preparing the adjuvant in and alicyclic organic reactants insofar as the existence termediates of my invention recourse can be made to sub 50 of seleno and telluro derivatives is concerned. That is stances differing from the above-described alcohols only to say, a somewhat scarce but nevertheless operative class to the extent that the hydroxyl group is replaced by a of reactants utilized in the preparation of my adjuvant Sulfhydryl group. Thus, the organic reactant used to intermediates comprises the seleno phenols and telluro prepare the intermediate products for the preparation of phenols. It will be apparent that such compounds are my adjuvants can be exemplified by such compounds as 55 substantially analogous to the phenols and thiophenols methyl mercaptan, ethyl mercaptan, propyl mercaptan, as above described with the exception that the one or isopropyl mercaptan, 1,2-ethane dithiol, allyl mercaptan, more oxygen- or sulfur-containing univalent radicals are cyclohexyl mercaptain, cyclohexene thiol, and analogous replaced by the corresponding selenium and tellurium compounds. In general, it is preferable to utilize mer functions. captains which contain up to about 30 carbon atoms in 60 With the aromatic organic reactants, it is preferred to the molecule. employ the phenols and thiophenols because of their lower As indicated hereinbefore, both seleno alcohols and cost, greater availability, and their generally superior phy telluro alcohols can be used as organic reactants in pre sical and chemical attributes. paring the adjuvant intermediates of this invention. It While the organic reactants described thus far generally will be appreciated that these substances are substantially 65 represent single chemical entities, it is frequently preferred analogous to alcohols with the exception that the hydroxyl to utilize as the reactant mixtures of the various mate function is replaced either by a seleno hydryl group or a rials, especially mixtures which are readily available as telluro hydryl group. As in the case of the mercaptains, articles of commerce. For example, typical mixtures of it is preferable to employ seleno alcohols and telluro organic compounds in which at least one carbon atom is alcohols which contain up to about 30 carbon atoms in 70 substituted with at least one univalent radical composed the molecule. solely of a group VI-B element and hydrogen are readily Because of their greater availability as articles of com available as products from fermentation and destructive merce, and their generally superior chemical and physical distillation processes. In such cases, the mixture consists characteristics, the alcohols and mercaptains as above de of various alcohols. Other readily available mixtures scribed are preferred over the seleno and telluro alcohols. 75 which can be utilized in the preparation of my adjuvant 2,794,720 5 6 intermediates include mixed mercaptains prepared by the stantial proportion of the product contains the character interaction of mixed alkyl halides and the monopotas istic grouping sium salt of hydrogen sulfidi in alcoholic solution, and S=P-(-A-C)3 mixed phenols obtained by heating mixtures of aryl hal ides with dilute aqueous sodium hydroxide in the presence wherein as before A represents a group V-B element. of copper salts in autoclaves at high temperatures. Other Thus, it would appear that although the reaction is be readily available mixtures of organic reactants will be lieved to involve chemical combination between the hydro come apparent to those skilled in the art. gen atom of the functional group of the organic reactant The phosphorus sulfide, the other prime reactant uti and the phophorus Sulfide, the reaction mechanism is ob lized as intermediate products for the preparation of my 10 scured by a number of concurrent effects including the adjuvants, is preferably a reactive compound such as P2S5 operation of the law of mass action, reaction kinetics, (P4S10) and P4S7. It is possible, however, to use cer steric factors as well as consideration of the nature of tain of the other reported phosphorus sulfides under the the prime reactants employed. It may well be that with proper reaction conditions. Furthermore, another related certain pure starting materials and with carefully con reagent which can be successfully utilized in preparing 15 trolled reaction conditions and concentrations substan my adjuvant intermediates is thiophosphoryl chloride, tially pure reaction products are obtainable. However, PSC3. It will likewise be apparent that under suitable an advantage inherent in this invention is the fact that conditions the various sulfides of arsenic or antimony can it is not necessary to prepare substantially pure materials be similarly employed in forming organolead adjuvant and further that it is generally preferred to utilize the intermediates for use in the present invention. 20 reaction product in toto as an adjuvant intermediate. The intermediate products for the preparation of the As indicated hereinbefore, the intermediate reaction adjuvants of this invention are readily prepared, the reac product can be used directly for the formation of my tion generally requiring only the addition of a reactive adjuvants or it can be subjected to an intervening treat phosphorus sulfide to the organic reactant and heating ment. Such treatment consists of centrifugation or fil the mixture at a temperature at which the reaction takes 25 tration to remove any by-product, sludge, or other in place as evidenced by the release of hydrogen sulfide until soluble material which under certain circumstances may the reaction is substantially complete. The temperature of be formed. Likewise, any excess of volatile reactant or the reaction is largely dependent upon the nature of the a volatile diluent, if used, can be removed by distillation. individual reactants although, generally speaking, tem Furthermore, if desired the intermediate product can be peratures in the order of about 150 F. to about 500 F. 30 extracted with a suitable solvent such as liquid propane are saisfactory. In preparing some of the adjuvant inter or isopropanol, or can be contacted with an adsorbent mediates of my invention advantages are to be obtained Such as activated charcoal, silica gel, activated clay or the by conducting the reaction under Super-atmospheric pres like. sure which can be readily obtained by conducting the re To prepare my organolead adjuvants the above-de action in a closed vessel thereby taking advantage of the scribed intermediate product is reacted with a suitable pressure resulting from the hydrogen sulfide so formed. salt of the desired metal. For example, the reaction inter The reaction products, that is, the adjuvant intermedi mediate can be treated with an oxide, hydroxide, car ates of this invention, can be made in the presence of a bonate, or the like of the metal in question. It will be diluent, if desired, which may or may not be subsequently apparent, therefore, that a wide variety of metallic ele removed. Such diluents are illustrated by such sub 40 ments can be introduced into the intermediate products stances as kerosene, straight run and catalytically cracked thereby forming organolead adjuvants for use in accord hydrocarbons of the diesel fuel boiling range and the like. ance with the present invention. However, generally The nature of the reaction products forming the adju speaking, a preferred embodiment of the instant inven vant intermediates of this invention is contingent to a tion consists of forming and hence utilizing reaction prod considerable degree upon the ratio of the reactants. That 45 ucts containing an alkali metal such as lithium, sodium, is to say, variations in the character of my adjuvant in potassium and the like. An additional preferred em termediates are achieved by utilizing different organic bodiment of this invention resides in the utilization of reactant-to-phosphorus sulfide atom ratios from between alkaline earth metal-containing reaction products as or about 0.5 to 1 to about 10 to 1. ganolead adjuvants. Thus, by reacting the product ob The reaction products used as the intermediate products 50 tained by reaction between a phosphorus sulfide and an for the preparation of my adjuvants in accordance with organic reactant as above described with a suitable salt this invention defy precise chemical definition. For ex of such metals as magnesium, barium, calcium, strontium, ample, in Kosolapoff, "Organo Phosphorus Compounds,” and the like, efficacious adjuvants of this invention are it is stated that there is very little reliable information formed. It will be apparent, however, that other metallic about the products obtained when the ratio of alcohol or 55 elements can be used to form suitable adjuvants. For phenol to phosphorus pentasulfide differs from 4 to 1. example, tin, zinc, aluminum, arsenic and other metals Nevertheless, it is known that the magnitude of the or higher in the electromotive series form highly desirable ganic reactant-to-phosphorus sulfide ratio employed con additives for use in accomplishing the objects of this in tributes a considerable effect upon the nature of my adju vention. The amount of the metallic salt used in pre vant intermediates. 60 paring my adjuvants can be sufficient to neutralize all or For example, when a low organic reactant-to-phospho part of the acidity of the intermediate reaction product. rus pentasulfide ratio is employed, that is, a ratio from The reaction itself is preferably carried out at an elevated between about 0.5 to 1 to about 2 to 1, it is generally be temperature in the range of about 180 to 350 F. in lieved that the reaction products contain a substantial pro order to complete the neutralization. portion of material containing the characteristic chemical 65 The particular conditions employed are naturally con bonding tingent upon the nature of the materials in question. By way of example, one general method which can be used S in forming my adjuvants is to conduct the reaction in H-s---A-C), the presence of a suitable diluent such as any of the typi O cal hydrocarbon solvents. Another modification used in wherein A is either oxygen, sulfur, selenium or tellurium preparing my adjuvants is to conduct the reaction at depending upon the nature of the organic reactant. On super-atmospheric pressure. This is found to be parti the other hand, when a high organic reactant to P2S5 ratio cularly efficacious in the preparation of metallic adju is employed, which ratio is from about 3 to 1 to about 10 wants of this invention formed from metals, the bases of to 1, it is presumed by those skilled in the art that a sub 75 which are relatively weak. Such is the case with alu 2,794,720 7 8 - - - m minum. On the other hand, the utilization of higher example, a facet of this invention involves the provision pressures is frequently unnecessary particularly when the of a mixture of an organolead antiknock agent such as metallic element being introduced into my organolead ad a lead alkyl and a metal-containing reaction product used juvants is capable of forming strong bases as in the case as an adjuvant in accordance with the present invention. of the alkali metals. In Such a case, the resulting composition can be blended Once the second step of the reaction has been com with hydrocarbon fuel of the gasoline boiling range to pleted the reaction product can be used in toto as an provide an improved fuel composition which under cer organolead adjuvant or it can be subjected to conven tain circumstances does not require the utilization of tional treatments of the type described hereinbefore. organic halogen-containing material as a scavenger. It Thus, recourse can be made to such steps as solvent ex O is believed that under these conditions the presence of traction, distillation, filtration, centrifugation, and the like. a quantity of phosphorus and Sulfur as above described While the preparation of my adjuvants has been de and chemically bonded in accordance with the require scribed in terms of a two-step process, it will be appre ments of the metal-containing reaction products used ciated that under certain circumstances, a one-step proc as an adjuvant in this invention contributes sufficient ess can be used. That is to say, with many of the prime 5 Scavenging action such that the amount and character reactants within the purview of this invention it is pos of deposition in the engine are suitably controlled, not sible to inter-mix suitable quantities with or without a withstanding the fact that lead phosphates generally have diluent and subject this mixture to thermal treatment until high melting points. Likewise, in this embodiment of the reaction is substantially complete. Further details the instant invention the general storage characteristics regarding this method of preparing my adjuvants will be 20 of organolead compounds are frequently enhanced. apparent to one skilled in the art. Of perhaps more practical importance is a second The organolead antiknock agent utilized in the com variant of this invention, namely the utilization of the positions of matter of the present invention consists of an aforesaid metal-containing reaction products in organo organolead compound in which lead is directly bonded lead-containing antiknock fluids. It is well known in to carbon atoms. Such compounds are exemplified by 25 the art that the most convenient means of marketing and the lead aryls such as tetraphenylead, and the lead alkyls blending organolead antiknock agents is in the form of such as tetramethylead, tetraethyllead, tetrapropyllead, an antiknock fluid which usually contains, in addition tetrabutyllead, dimethyldiethylead, methyltriethylead, to the lead compound, one or more organic bromine and the like, as well as mixtures of such compounds. and/or chlorine compounds and an organic dye for iden Because of the generally superior characteristics of tetra 30 tification purposes. On occasion such antiknock fluids ethyl lead and the ready accessibility thereof as an article likewise may contain minor proportions of diluents, anti of commerce, it constitutes a preferred embodiment of the oxidants, metal deactivators and the like. In line with organolead antiknock agent utilized in accordance with the foregoing, therefore, a preferred embodiment of this the instant invention. invention involves providing improved antiknock fluids With the various compositions within the scope of this 35 containing the requisite concentration of the above-de scribed metal-containning reaction products. Such im invention the proportion of the metallic reaction prod proved antiknock fluids generally do not require the pres uct utilized in conjunction with an organolead compound ence of a solubilizing agent or a stabilizer since the phos is such that there is a total of from between about 0.01 phorus compound itself is generally sufficiently miscible to about 0.80 theory of phosphorus. In this regard a 40 with the constituents of the antiknock fluid and imparts theory of phosphorus is defined as the amount of phos thereto a degree of stabilization. However, under some phorus theoretically required to react with the lead to conditions additional benefits are to be derived by em form lead ortho phosphate, which quantity is two atoms ploying in the improved antiknock fluids of this inven of phosphorus per three atoms of lead. However, gen tion the necessary quantities of such materials. erally speaking, it is sufficient to employ an amount of 45 Still another variant of the present invention consists an organolead adjuvant of this invention such that there of providing improved fuel compositions. These nor is an amount of phosphorus between about 0.05 and about mally consist of hydrocarbons of the gasoline boiling 0.5 theory with the best overall results usually being ob range containing a minor proportion of the aforesaid tained with announts of about 0.1 to about 0.2 theory of antiknock fluids of the present invention. It will be ap phosphorus, the last-mentioned concentrations constitut preciated that the quantity of the antiknock fluid of the ing a preferred embodiment. present invention utilized in my improved fuel compo Regarding many of the problems frequently associated sitions is primarily contingent upon the use for which with high octane quality fuel, an anonhalous situation the gasoline is intended. That is to say, when the fuel obtains. On one hand, an effective adjuvant for organo is intended for use in automotive engines such as pas lead compounds should possess stability against deteriora 55 Senger cars, trucks, buses and the like, an amount of tion in common environments, compatibility with the any of my improved antiknock fluids equivalent to a chemical entities with which it comes in contact, and lead content in the gasoline of from between about 0.53 volatility so as to possess the characteristic frequently re and about 3.17 grams of lead per gallon is satisfactory. ferred to as engine inductability. On the other hand, Thus, in the embodiments of this invention wherein I the mere selection of a phosphorus compound to acquire 60 employ tetraethylead as an antiknock agent such con the optimum characteristics enumerated above does not centrations are equivalent to from between about 0.5 and necessarily assure the effectiveness of the compound in about 3 milliliters of the compound per gallon. With combatting such phenomena as spark plug fouling, wild the advent of the more recent high compression ratio in ping the like. It is entirely probable that some empirical ternal combustion engines, however, it is becoming in relationship between physical properties and effective 65 creasingly apparent that benefits are to be derived by ness in the obviation of such problems exists, but as yet employing somewhat greater concentrations of the organo the state of the art does not contain a satisfactory rela ead material in automotive gasoline. On this basis, tionship of this type. However, the phosphorus mate therefore, automotive fuels containing up to about 4.75 rials within the purview of this invention, for the most grams of lead per gallon are contemplated. In contrast, part, possess the requisite physical properties adapting when the improved antiknock fuids of the present inven them for use as organolead adjuvants and at the same tion are utilized in fuel for aviation engines somewhat time are effective in obviating engine problems of the type higher concentrations are employed. Generally speak described hereinbefore. ing, amounts of lead up to about 6.34 grams of lead It will be apparent that there exists a number of varia per gallon can be utilized although somewhat lesser quan tions in employing the adjuvants of this invention. For tities are presently in vogue. In other words, in the 2,794,720 10 tetraethylead-containing embodiments of this invention Example III there can be present up to about 6 milliliters of tetra In a suitable reaction vessel are placed 149 parts of ethylead per gallon as an improved antiknock fluid of amyl mercaptain and 222 parts of phosphorus heptasul my invention. Concentrations above these limits can be employed in both motor and aviation fuels, practical fide (PAS). The temperature of the reactants is then considerations being the prime criterion for establish raised to 325 F. and maintained at this temperature ing the upper concentration limit. As indicated herein for four hours while continuously agitating the mixture. above, in all of the compositions of the present inven At the end of this time the reaction mass is diluted with tion the amount of phosphorus is fixed within the limits an equal volume of toluene. The solution is then allowed above described. Thus, in the preferred fuel embodi O to stand for fifteen minutes during which time minor ments of my invention there is present an amount of amounts of solid products have settled to the bottom of phosphorus as a metal-containing reaction product such the container. These are removed by subjecting the en that there is from about 0.1 to 0.2 theory of phosphorus. tire product to filtration. To 500 parts of the filtrate In preparing the improved fuel compositions of this in is added 250 parts of an aqueous solution of potassium vention, it is usually necessary only to add the requisite s hydroxide containing 40 parts of the hydroxide per liter. quantity of the improved fluid to the fuel and by means The resulting mixture is then heated for 2 hours at a of stirring, shaking or other means of physical agitation temperature of 180° F. and then for 2 more hours at honogeneous fuel compositions are provided. Although a temperature of 250 F. while passing air through the the simplest means of preparing Such fuels is to blend mixture. After this treatment it is preferable to filter therewith the necessary quantity of an improved anti 20 the reaction products while hot. knock fluid of this invention, it is possible to add a con The reactants and reaction conditions described in ventional antiknock fluid to the fuel and subsequently the previous specific examples are merely illustrative. blend therewith the necessary quantity of the metal For example, by utilizing the above and similar reaction containing reaction product. In addition to reversing conditions it is possible to prepare suitable adjuvants by this order of addition of conventional antiknock fluids 25 reaction a phosphorus sulfide such as P2S5, P4S1 and and metal-containing reaction products used as adjuvants the like with such organic reactants as abietyl alcohol, in accordance with this invention, another variant is to terpineol, amyl mercaptain, p-butyl thiophenol, and in blend with the fuel each of the individual constituents of turn the product with calcium oxide, or the hydroxides my antiknock fluids separately. of tin, barium, strontium, magnesium and the like. The following specific examples wherein all parts and 30 Furthermore, as indicated previously it is possible to percentages are by weight are illustrative of the meth utilize thiophosphoryl chloride in forming the adjuvant ods which can be employed in preparing the adjuvants intermediates of this invention. When this is done and of this invention. a low organic reactant-to-thiophosphoryl chloride mole Example I ratio is employed, hydrolytic treatment with hydrogen 35 Sulfide should follow the thermal step. Generally speak To a suitable glass reaction vessel equipped with an ing, such low mole ratios are in the order of from about electric heating mantle and a stirrer is added 250 parts 1 to 1 to 2 to 1, although minor deviations from these of 2-ethylhexanol and 750 parts of virgin gas oil. To ratios can be utilized. When a high organic reactant this mixture is then added 222 parts of phosphorus penta to-thiophosphoryl chloride mole ratio is employed such sulfide (P2S5). The temperature of the vessel is then hydrolytic treatment is generally unnecessary. In such raised to 250 F. and maintained at this temperature for a case, however, it is frequently desirable to conduct the a period of about two hours while vigorously agitating reaction in the presence of a hydrogen chloride acceptor the reactants. Upon completion of the reaction the prod Such as amines, pyridines and the like. luct is subjected to centrifugation and filtration so as to To illustrate the effectiveness of the improved anti remove the minor quantities of undesirable products knock fluids of the present invention consideration can which are formed. To 500 parts of this product is added 45 be given to the problem of spark plug fouling. In order 200 parts of lithium hydroxide and 200 parts of water. to do this, recourse can be made to the following gen This mixture is heated to a temperature of 180 F. for eral test procedure utilizing a standard modern V-8 en 2 hours, after which time the temperature is raised to gine equipped with overhead valves having a 334’ bore, 250 F. for an additional 2 hours. During the latter a 37Ag' stroke, a 303.7 cubic inch displacement and a period of heating air is passed through the reaction mix compression ratio of 7.25 to one equipped with com ture so as to strip therefrom excess water. Upon com mercially available spark plugs. In order to establish pletion of this step the reaction mixture is filtered while a base line this engine is operated in conjunction with hot to remove minor quantities of solids which have an engine dynamometer on a standard commercial fuel formed. 55 containing 3 milliliters of tetraethyllead per gallon as Example II conventional antiknock fluid containing 0.5 theory of bromine as ethylene dibromide and 1.0 theory of chlo To a suitable glass reaction vessel equipped with an rine as ethylene dichloride. This is operated under a electric heating mantle and a stirrer is added 250 parts durability schedule used for spark plug deposit accumu of 2-ethylhexanol and 750 parts of virgin gas oil. To 60 lation patterned after road conditions experienced in this mixture is then added 222 parts of phosphorus penta city driving which are known to produce spark plug Sulfide (P2S5). The temperature of the vessel is then fouling of the greatest magnitude. Such operation is raised to 250 F. and maintained at this temperature Substantially continuous until a number of spark plug for a period of about two hours while vigorously agitat failures is detected thereby establishing a quantitative ing the reactants. Upon completion of the reaction the measure of the degree of spark plug fouling which can product is subjected to centrifugation and filtration so be expressed in average hours to plug failure. The en as to remove the minor quantities of undesirable prod gine is then freed from deposits and equipped with new ucts which are formed. To 500 parts of this product is Spark plugs. The same procedure is repeated using the added 110 parts of freshly precipitated zinc oxide and same fuel base stock to which is added an improved anti 100 parts of Water. This mixture is then heated for 2 70 knock fluid of the present invention. hours at 180 F. The temperature is then raised to By Way of example, when 300 gallons of a petroleum 250 F. for an additional 2 hours while contemporane hydrocarbon fuel available as an article of commerce is ously blowing air through the reaction mixture. At treated with 900 milliliters of tetraethylead in a fluid the end of this time the product is filtered, preferably containing tetraethyllead, 0.5 theory of bromine as ethyl while hot. 75 ene dibromide and 1.0 theory of chlorine as ethylene di 2,794,720- Y - -, -m or 11 - . - 12 chloride, a suitable fuel is prepared for establishing a obtained using the fuel treated with a metal-containing base line of hours to spark plug failure. When the reaction product with those obtained using a fuel treated standard V-8 engine described hereinbefore is then op with a conventional antiknock mixture. Since the wild erated on this homogeneous fuel composition it is found ping counter records the total number of wild pings which that in an average time of about 34 hours 3 spark plug have occurred during the test procedures a quantitative failures have occurred. expression for the amount of deposit-induced autoigni In contrast, when a suitable quantity of the same fuel tion is the number of wild pings per hour of operation. base stock is treated with an improved antiknock fluid The effectiveness of my improved fuel composition in of the present invention greatly enhanced spark plug virtually eliminating deposit-induced autoignition will be life is obtained. For example, when 1000 gallons of apparent from the following specific examples. the same fuel base stock is treated with 3 liters of tetra Example IV ethylead as a fluid comprising 0.5 theory of bromine as ethylene dibromide, 1.0 theory of chlorine as ethylene di To 100 gallons of a commercially available blend of chloride, and 0.2 theory of phosphorus as the strontium straight run, catalytically cracked and polymer blending salt of a PSC3-amyl mercaptain reaction product, an im 15 stocks was added and thoroughly mixed 300 milliliters of proved fuel of the present invention results. Upon tetraethylead as an antiknock fluid comprising tetra intimately mixing the aforementioned components the ethylhead, 0.5 theory of bromine as ethylene dibromide, homogeneous fuel composition containing 3.0 milliliters and 1.0 theory of chlorine as ethylene dichloride. The of tetraethyl lead per gallon is suitable for use in the resulting homogeneous fuel composition was then utilized above-described engine test procedure. It is found that 20 as the fuel in the previously designated single-cylinder a substantial improvement in spark plug performance laboratory test engine to formulate a base line of wild as evidenced by the greater period of continuous engine ping. It was found that there were 135 wild pings per operation results from the utilization of such improved hour of engine operation. fuel of the present invention. That is to say, the av Example V erage hours to three spark plug failures is substantially 25 An improved antiknock fluid composition of the pres in excess of the base line figure of 34 hours. ent invention is prepared by adding 0.1 theory of phos When such adjuvants as the beryllium salt of P2S5 phorus as the product obtained by reaction between cardanol, the lithium salt of P2S5-terpineol, the zinc salt P2S5, 2-ethylhexanol, followed by reaction with lithium of PSCl3-nonanol and the like are utilized in accordance 30 hydroxide to 150 milliliters of tetraethylead as an anti with the present invention comparable effectiveness re knock fluid comprising tetraethyllead, 0.5 theory of bro garding minimization of spark plug fouling is obtained. mine as ethylene dibromide, and 1.0 theory of chlorine Without desiring to be bound by the following explana as ethylene dichloride. A homogeneous fluid composi tion regarding the enhanced effectiveness of the ad tion is obtained by intimately mixing the aforementioned juvant intermediates of this invention, a tenable explana 35 components. The entire quantity of improved anti tion apparently involves a proper balance between phys knock fluid composition so prepared is added to 50 gal ical properties such as stability, volatility, solubility, lons of a commercially available blend of straight run, compatibility and the like and the energy relationships catalytically cracked and polymer blending stocks. Upon or ease of decomposition which may attribute to the over mechanically agitating the resulting mixture a homoge all effectiveness of my adjuvant intermediates by facili neous fuel composition is prepared. The laboratory tating decomposition at the proper instant in the engine 40 single-cylinder test engine as described previously is then cycle. operated on this improved fuel composition while con To still further illustrate the enhanced effectiveness temporaneously determining the rate of wild pings as of the organolead-containing compositions of the present detected by the wild ping counter. It is found that the invention consideration can be given to the problem of utilization of an improved antiknock fuel of the present wild ping. To demonstrate the effectiveness of my com 45 invention greatly minimizes the rate of wild pings ex positions in this regard, I can subject both a hydrocarbon pressed in wild pings per hour as contrasted with a con fuel treated in accordance with this invention and another ventional fuel which produces 135 wild pings per hour. portion of the same hydrocarbon fuel treated with a con Consequently, an improved fuel composition of this in ventional antiknock mixture to a test procedure involv vention results in a substantial reduction in this deposit ing the use of a single-cylinder CFR knock test engine 50 induced engine phenomenon. equipped with an L-head cylinder and a wild ping counter The foregoing specific examples are merely illustrative which records the total number of wild pings which have of the beneficial effects produced by the improved or occurred during the test periods. Such apparatus includes ganolead-containing compositions of the present inven an extra spark plug used as an ionization gap which is tion. It will be apparent that it is preferred to utilize installed in a second opening in the combustion cham such metallic reaction products as the sodium salt of ber. A mechanical breaker switch driven at camshaft P2S5-thiophenol, the magnesium salt of P4S1-butanol, the speed is also provided which, when closed, makes the aluminum salt of PSCla-amyl mercaptain and the like in wild ping counter ineffective for the duration of the nor high octane quality fuel because of the fact that most of mal flame in the combustion chamber. The breaker is 60 the deposit-induced problems exist on combustion of such open for 80 crankshaft degrees between 70 B. T. C. fuels. (before top dead center) and 10 A. T. C. (after top The superior effectiveness of the preferred embodi dead center). If a flame front induced early in the cycle ments of this invention, namely a metal-containing re by deposits reaches the ionization gap during this open action product as defined hereinbefore, in the diminution period, the counter registers a wild ping regardless of the of deposit-induced engine problems is further unexpected audible manifestations. During normal combustion with 65 ignition timing at T. D. C. (top dead center) the flame when considering the prime constituents phosphorus and front reaches the ionization gap at 15 to 18 A.T. C. sulfur which are contained therein. On the one hand, during the period wherein the points are closed and no both sulfur and phosphorus compounds have heretofore count is made. The actual test procedure consists es been judiciously avoided as much as possible in fuel sentially of operating the test engine initially having a 70 because of their notorious deleterious effects particularly clean combustion chamber under relatively mild cycling in the realm of organolead antagonism and the like. In conditions for deposit formation until an equilibrium the case of sulfur, for example, refiners have long been with regard to deposit-induced autoignition is reached. resorting to various means of removing sulfur compounds The effect of fuels treated in accordance with the instant from hydrocarbons of the gasoline boiling range because invention is determined by comparing the test results 75 of their recognized deleterious effects on antiknock ac 2,794,720 13 4. tivity, engine cleanliness, storage stability, and the like. Having fully described the nature of the present invert However, the adjuvant intermediates of this invention tion, the need therefor, and the best mode devised for possessing considerable profortions of phosphorus and carrying it out, it is not intended that this invention be sulfur do not bring about such deleterious effects. Fur limited except within the spirit and scope of the appended thermore, another surprising effect has been noted, claims. namely the fact that the presence of phosphorus-to-sulfur I claim: bonds produces a greater effectiveness regarding wild 1. An antiknock additive for use in hydrocarbon fuels ping than that exhibited by compounds possessing either of the gasoline boiling range, said additive comprising an phosphorus or sulfur and likewise a mixture of phos organolead antiknock agent and a metallic derivative of phorus- and sulfur-containing compounds. This fact is O a product obtained by reaction between (1) an organic evidenced by the findings that the presence of added compound in which at least one carbon atom is substituted sulfur in a conventional leaded fuel not only has no with at least one univalent radical composed solely of a beneficial effect on wild ping but actually results in an group VI-B element and hydrogen, said radical being increase in this phenomenon. By way of example, it bonded to said carbon atom through said group VI-B was found that the addition of 5 theories of Sulfur as a 5 element, said compound containing only elements selected mixture consisting of one theory of di-t-butyl disulfide, from the group consisting of carbon, hydrogen, oxygen, 2 theories of dibutyl sulfide and 2 theories of thiophene, sulfur, selenium, and tellurium, and (2) a phosphorus a mixture representative of the average sulfur constituents sulfide selected from the group consisting of P2S5 and of petroleum hydrocarbon fuel, to a conventional gaso P4S1, said product being prepared by heating from about line containing 3 milliliters of tetraethyllead per gallon 20 0.5 to about 10 moles of said compound per mole of said resulted in a wild ping rate of 93 wild pings per hour. sulfide to a temperature at which hydrogen sulfide is re In contrast, the same fuel containing the same concen leased, said metallic derivative being prepared by re tration of tetraethyllead produced 74 wild pings per hour. acting said product at a temperature in the range of about Thus, the incorporation of sulfur-containing compounds 180 to 350 F. with an amount of a metallic base selected different from the sulfur-containing adjuvants utilized in 25 from the group consisting of oxides, hydroxides, and car this invention resulted in a wild ping rate amounting to bonates sufficient to neutralize at least a part of the acidity 125 percent of the base line. That is to say, the presence of said product; said metallic derivative being present in of sulfur-containing compounds generally increases the said additive in amount such that the phosphorus-to-lead rate of wild ping whereas the presence of a considerable atom ratio is from about 0.02/3 to about 1.6/3. amount of sulfur when suitably bonded in accordance 30 2. The additive of claim 1 further characterized in that with the present invention results in a definite improve the antiknock agent is a lead alkyl. ment in this deposit-induced phenomenon. In view of 3. The additive of claim 1 further characterized in the foregoing, therefore, the apparent conclusion to be that the antiknock agent is tetraethylead. reached is that the chemical bonds between the two 4. An antiknock additive for use in hydrocarbon fuels prime elements making up my adjuvant intermediates in 35 of the gasoline boiling range, said additive consisting some currently unexplainable manner produce enhanced essentially of tetraethyllead, a scavenging amount of or effectiveness with regard to deposit-induced engine phe ganic halide material capable of reacting with the lead nomena without resulting in secondary deleterious prob during combustion in a spark ignition internal combustion lems normally attributed to the presence of each of the engine to form volatile lead halide, said material con elements when used separately or as mixtures of indi 40 taining only elements selected from the group consisting vidual phosphorus- and sulfur-containing compounds. of bromine, chlorine, carbon, hydrogen, and oxygen; and As indicated, an additional important advantage ob a metallic derivative of a product obtained by reaction tained from practicing this invention is the fact that my between (1) an organic compound in which at least one adjuvants have little or no antagonistic effect upon the carbon atom is substituted with at least one univalent antiknock agent used in the fuel. In line with the en radical composed solely of a group VI-B element and hanced effectiveness of my organolead adjuvant inter 45 hydrogen, said radical being bonded to said carbon atom mediates this surprising benefit regarding a minimum of through said group VI-B element, said compound con organolead destructiveness is perhaps associated with the taining only elements selected from the group consisting degree of oxidative stability inherent in my metal-con of carbon, hydrogen, oxygen, sulfur, selenium, and tel taining reaction products. In other words, it is not in lurium, and (2) a phosphorus sulfide selected from the conceivable that my organolead adjuvants are capable of 50 group consisting of P2S5 and P4S1, said product being decomposing at the proper instant in the engine cycle so prepared by heating from about 0.5 to about 10 moles of as to exhibit the beneficial effect regarding deposit-induced Said compound per mole of said sulfide to a temperature engine problems while at the same time decomposing at at Which hydrogen sulfide is released, said metallic deriva a time during the engine cycle sufficiently far removed 55 tive being prepared by reacting said product at a tempera from the point at which the organolead compound ex ture in the range of about 180 to 350 F. with an amount erts its beneficial antiknock activity. of a metallic base selected from the group consisting of Because of their adaptability the adjuvant interme oxides, hydroxides, and carbonates sufficient to neutralize diates of the present invention can be successfully utilized at least a part of the acidity of said product; said metallic with any of the well known organolead antiknock agents 60 derivative being present in said additive in amount such as indicated hereinbefore. Likewise, insofar as the halide that the phosphorus-to-lead atom ratio is from about scavengers are concerned, the metal-containing reaction 0.02/3 to about 1.6/3. product used as an adjuvant in accordance with this in 5. The additive of claim 4 further characterized in vention can be employed in antiknock fluids and fuels that said scavenging amount of organic halide material is containing such materials as ethylene dibromide, ethylene 65 about 0.5 theory of bromine as a bromohydrocarbon dichloride, mixed dibromotoluenes, trichlorobenzenes, compound capable of reacting with the lead during com and, in general, such organic halide scavengers as those bustion in a spark ignition internal combustion engine to disclosed in U. S. 1,592,954; 1,668,022; 2,364,921; form volatile lead bromide, and about 1.0 theory of 2,398,281; 2,479,900; 2,479,901; 2,479,902; 2,479,903; chlorine as a chlorohydrocarbon compound capable of and 2,496,983. Likewise, the adjuvant intermediates of 70 reacting with the lead during combustion in a spark igni this invention can be used in conjunction with other well tion internal combustion engine to form volatile lead known motor fuel adjuvants such as antioxidants, organo chloride. lead stabilizers, organic dyes, solubilizers, and indeed with 6. Hydrocarbon fuel of the gasoline boiling range other catalytically active materials frequently employed adapted for use as fuel for spark ignition internal com in fuel. 75 bustion engines containing up to about 6.34 grams of 2,794,720 15 - 16 lead per gallon as an organolead antiknock agent, and a characterized in that it contains from about 0.53 to metallic derivative of a product obtained by reaction about 4.75 grams of lead per gallon as tetraethyl lead, between (1) an organic compound in which at least one about 0.5 theory of bromine as a bromohydrocarbon carbon atom is substituted with at least one univalent compound capable of reacting with the lead during com radical composed solely of a group VI-B element and bustion in a spark ignition internal combustion engine to hydrogen, said radical being bonded to said carbon atom form volatile lead bromide, and about 1.0 theory of through said group VI-B element, said compound con chlorine as a chlorohydrocarbon compound capable of taining only elements selected from the group consisting reacting with the lead during combustion in a spark igni of carbon, hydrogen, oxygen, sulfur, selenium, and tel tion internal combustion engine to form volatile lead lurium, and (2) a phosphorus sulfide selected from the O chloride. group consisting of P2S5 and P4S1, said product being 8. The composition of claim 6 wherein the metal of prepared by heating from about 0.5 to about 10 moles of said metallic derivative is selected from the group con said compound per mole of said sulfide to a temperature sisting of alkali and alkaline earth metals. at which hydrogen sulfide is released, said metallic deriva tive being prepared by reacting said product at a tempera 5 References Cited in the file of this patent ture in the range of about 180 to 350 F. with an amount UNITED STATES PATENTS of a metallic base selected from the group consisting of oxides, hydroxides, and carbonates sufficient to neutralize 2,378,793 Rudel ------June 19, 1945 at least a part of the acidity of said product; said metallic 2,405,560 Campbell ------Aug. 13, 1946 derivative being present in said fuel in amount such that 20 2,534,217 Bartleson ------Dec. 19, 1950 the phosphorus-to-lead atom ratio is from about 0.02/3 FOREIGN PATENTS to about 1.6/3. 7. The hydrocarbon fuel composition of claim 6 further 683,405 Great Britain ------Nov. 26, 1952