US2380072A - Sulphurized hydrocarbon and method of preparation - Google Patents

Description

" Patented July 10,

UNITED. .srA-r'ss SULPHURIZED HYDBOCABBON METHOD OF PREPARATION James A. Reid, ncruc'muc, kla., a'ssignor to.- Philllps Petroleum Company, a corporation of Delaware Serial No. 433,688

No Drawing. Application March c. 1942,

7 Claims;

This inventiom relates to a sulphur-con s hydrocarbon, and more particularly to a sulphur derivative of an aliphatic hydrocarbon, to a proo ess for'manufacturing this product, and to a process of modifying lubricating oils 'with this product. d

In the progressive development of lubricants it has been found that specific qualities and general utility of hydrocarbon oils can be improved b incorporating small amounts c various materials. commonly generalized as a ditives. An additive may serve to improve the quality of a lubricant in any one or more of several ways,

fir example, by decreasing the rate of oxidation,

creasing the illm strength, increasing the dispersing po'werof, an oil for insolubles, and so forth. .At times it may be desirable to use more thanone additive in an oil in order to ,impart properties making it most suitable for some specific application. A wide, variety of compounds and mixtures has been disclosed .in the field of lubricant additives. Y

Most lubricating oils can be improved by adding small amounts of selected oxidation inhibitors.

These inhibitors are particularly efiective in synthetic oils and in oils which have been subjected to intensive refining processes. Thenatural lu-' bricants contain small amounts of materials that act as oxidation inhibitors, but these are largely removed by many refining treatments, particularly solvent extraction treatments. In most-cases the highly refined lubricants produced at the present time are inferior in resistance to oxidation to the lubricants produced by the previously conventional methods, such as acid and clay treating, althoughthey'may be superior in other respects,'-.such as viscosity index. The addition oi inhibitors to these oils is necessary to impart sta bility for satisfactory engine lubrication.

The synthetic lubricants, such as those produced'by' the hydrogenation of olefin polymers, may be particulaiiy susceptible'to oxidation as compared to natural lubricants. In these cases,- also,'-high resistance to-oxidation can be imparted to the oil by adding selected oxidation inhibitors.

Thedevelopment of oxidation inhibitorsfor oils is thereforeof great importance, but is complicated by the "severe req irements that the inhibitor itself must meet. Any material added to an oil to improve one'property should not adverse-' ly affect any other property. The inhibitor itself should not be corrosive to engine parts. The concentration in the oil should not decrease rapidly during'llse either from loss by volatilization, "from. rcfcrcnusvceccmp mcn by the action of heat, from excessive reaction with engine parts, or from other causes. The inhibitor should 'not impart an undesirable color or odor to the oil, or in any other manner adversely affect the 5 utility or performance of the oil.

Many attempts have been made to develop additives-that improve more than one specific quality of an: oil; the advantages of thistype of additive are readily appreciated. For example, liiflcertain additives have been claimed to both in-' crease film strength and inhibit oxidation, others have been claimed to decrease the pour point and increase film strength, and still other combinations of properties have been claimed for specific Sulphur or compounds containing sulphur have been used in cutting oils and oils used in other applications where high pressures are developed between the moving metal surfaces. More re- .20 eently this type 01' lubricant has been extensively used in the hypoid gears of automobile diflerentials'. These lubricants are known as extreme pressure" lubricants because the film of lubricant 'must withstand the high pressures emstlng at the points of gear contact. In these applications, it is important that the activity of thesulphur be so controlled as to eliminate seizure and or tearing of the metal surfaces, but must be sumciently resistant to change to introduce no 3." objectionable characteristics.

More; recently, organic materials. containing- 7 sulphur have been used as additives for crankcase lubricating oils. For crankcase lubrication.- high film strength is not a critical property, but if high film stren th can be obtained without sacrificing other properties, it is very desirable, because 'such an oil will minimize engine failures caused by seizure of close-fitting parts, particularly during the break-in period, and may decrease general maintenance requirements 01 the engine; The

' most .important function of sulphurized 4 compounds in crankcase oils is the inhibition of cmda ion. The efiect of oil oxidation has briefly summarized hereinbefore, and the importance of 'oxidationcontrol pointed out. Certain types of sulphurized compounds have proven eflfective for diminishing the rate of oxidationo'f oils. It has appeared that this inhibition of oxidation results Primarily from a deactivation of the metal catalysts found in an engine, especially iron and iron salts.

One general group of sulphurized materials have prepared by reacting unsaturated organic compounds with-sulphur or active sulphur com-' pounds. :such assulphurchloride, for example 7 Various natural oils have been used as the unsaturated charge, but these oils usually contain a wide variety of organic materials having several points of reactivity, so that the resultant sulphurized oil is a heterogeneous mixture of sulphur compounds.

It is an object of this invention to provide an improved material for use as a lubricant additive.

Another objectof this invention is to provide a sulphurized hydrocarbon of uniform composi- Another object of this invention is to provide cant additive in which the position of the sulphur in the molecule is controlled.

, Another object of this invention is to Provide a sulphurized hydrocarbon to be used as a lubricant additive in which the activity of the. sulphur is controlled.

Another object of this invention is to provide a light-colored uniform type of organic sulphur compound to be used as a lubricant additive.

Still another object of this invention is to prepare a relatively stable sulphur-containing hydrocarbon in which the reactivity of the sulphur is carefully adjusted and uniformly controlled.

Another object of this invention is to disclose a sulphur derivative of an aliphatic hydrocarbon. in which the activity of the sulphur is uniformly adjusted to the proper value for specific applications. s

Other objects will be evident to one skilled in L the art from the accompanying description and discussion.

The olefin hydrocarbons used in the embodiment of my invention are prepared by polymerizing low molecular weight mono-oleflns, preferably ethylene or mixtures containing ethylene.

' 700 C., and passing over the catalyst a stream using as catalyst 'an oxide of an iron group metal.

such as nickel oxide prepared as hereinafter disclosed which is eifective in polymerizing olefin hydrocarbons. Such a catalyst may be prepared from an active nickel-on-kleselguhr hydrogena-' tion catalyst, by heating the catalyst to a temperature above about 450 C., but not above about of inert gas containing a small percentage of oxygen, for example a mixture of nitrogen and oxygen containing about 2 to 10 per cent oxygen,

f-until substantially all of the nickel has been converted to oxide. The oxidation is preferably so conducted that a uniform temperature prevails throughout the catalystmass. and that uniform oxidation is obtained. .One means of achieving this is to agitate the catalyst during the oxidation process.

' The mono-oleiin-containing charge is polymerized by contacting it with the catalyst at a temmonia, carbon monoxide, certain organic compounds containing oxygen, sulphur or halogens and other materials the exact nature of which.

mercial olefins, such as ethylene, or high purity may advantageously be further purified by passage over reduced nickel-on-kieselguhr hydrogenation catalyst at about 175 C. and then through sodium hydrate adsorbent at room temperature. Further improvement in catalyst life has-been obtained by operating the catalyst in the presence of an alkali metal, alloy, or amalgam of alkali metals, preferably in the liquid state. It is believed that these added metals act to remove traces of materials introduced into or formed in the reaction system that adversely affect the activity of the catalyst.

The products obtained by the polymerization of ethylese range from butenes to high melting point axy hydrocarbons. Asfraction containing oleflns of 16, or more, carbon atoms per molecule. is separated for use as sulphurlzation charge stocks. For example, the low boiling olefins are removed by distillation, leaving a residue boiling above about 300 C. This residue is a colorless semi-solid waxy olefin containing one double bond per molecule. All of this residue may be used, or some fraction thereof of narrow-boiling range.

The .olefinic products of this polymerization system have been found to contain no tertiaryperature in the range of about 50 to 200 C. and a pressure in excess of atmospheric, usually in the range of 400 to 1500 p. s. i. Ethylene is .the preferred olefinic charge, since polymers of higher molecular weight and more limited chain ,branch- 1 ing result from it than from other reactive olefins.

. The catalyst for this polymerization is very sensitive to certain poisons, such as. sulphur, arm

base olefins, and substantially no chain-branching, as indicated by their waxy nature or high melting point. There are no cyclic or aromatic hydrocarbons, in the product. It is thus apparent that ethylene is converted to polymeric products in this catalytic system by simple polymerization without isomerization, hydrogenation, or other changes. The double bond is at or near the terminal position in the olefin molecules, and I believe that the favorable results realized are obtained because I am able to produce normal olefins of 16 or more carbon atoms per molecule and to produce sulphurized products therefrom.

The polymeric products from propylene and higher boiling oleflns are less desirable in that the polymers are lower in molecular weight, and greatly increased numbers of side-chains are found in the polymers.

The uniformity of molecular structures and characteristics of these polymers from nickel oxide catalyzed polymerizations makes them well suited for conversion with sulphur to sulphurized products of uniform activity without further segregation or purification. In addition, through control of the proportion of sulphur combined with the olefin, the activity of the sulphur compounds may be controlled within relatively narrow limits.

The polymers produced from ethylene by means of the nickel oxide'or similar catalyst thus differ in significant properties from the polymers produced in the presence of acid, metal halide, or .clay-type catalysts; the latter polymers contain generally tertiary-base olefins, extensive chain branching, internal unsaturation, and so forth, and frequently undergo isomerization, cyclization and other secondary changes during processing;

Sulphur may be introduced into polymer frac- .preparations of sulphurized hydrocarbons, in

- tion catalyst containing 55 per cent nickel'was period and the furnace held at the initial tem- 75 such conditions that the ethylene is polymerized ing compounds; however, these means or introperature. The catalyst was cooled and transducing sulphur are not equivalent. A preferred ferred to a pressure autoclave containing one p of reaction product results from the heating of about two to fifteen parts by weight of pentane and one-twentieth part of metallic sulphurwitlr 100 parts of oleflnic hydrocarbon 5 sodium. The autoclave was "assembled and at a temperature in the range or from 180 to 280 heated to 110 0., and purified ethylene'was in- C. for a period of about 1 to hours. The pro- 'troduced to a total pressure of 600 pounds per portion of sulphur used depends on the molecular square inch gauge. As the polymerization pro I weight of the po1ymer and the desired activity seeded, more ethylene was added to maintain theof the product. In general, the proportion of sul- 10 pressure at the original figure. The autoclave phur used is in the range of 0.4 to 2.0 atoms was continuously shaken, and the temperature of sulphur per molecule of oleflns, although in was hel at ll0-115 C. Two hundred parts by some applications higher proportions oi! sulphur weight of ethylene were polymerized during a may lie desirable. The reactivity of the result 5 hour period. a

ing sulphur compounds increases with increase The reaction was ,discontinuedand the product in sulphur content of each molecule of the rewas removed from the reactor. The product action product. It is usually necessary that the sulphur be tion, leaving a colorless semi-solid waxy residue. completely combined with the hydrocarbon, so Ten parts by weight of this residue was mixed thatno highly corrosive elementary sulphur rewith 10 parts of paraflinic oil and one p f and one half parts by weight purified normal boilin'gbelow 300 C. ,was removed by distillamains in the mixture. In some cases, especially sulphur. The mixturewas stirred and heated with the lower proportions of sulphur, the reto C. for six hours. During this period the action can be completed'by heating'the reactants (color deepened from a light yellow to a reddish in the preferred temperature range of 210 to vorange as the sulphur reacted Withthe Olefin. 240 C. During the reaction, the solution grad- 2s No evolution of hydrogen sulphide was detected. ually changes in color from alight yellowim- At the end of the stated time the, reaction was parted by the dissolved sulphur to the reddish complete, as indicated by the absence of eleorange color of the sulphur-containing products. mentary (corrosive) sulphur. No gas is evolved, and no black or insoluble A highly refined lubricating oil was used in a compounds aretormed during the reaction. four-cycle engine operating under severe condi- In some cases the reaction of sulphur with the tions for 50 hours; the itest was repeated using very pure olefin proceeds at a very low rate. another portion of the highly refined oil to which Small amounts of various materials may be added 4 per cent of the sulphurized oil previously deto the reaction mixture to accelerate the rescribed was added. The difierence in oxidation 01'1 action, to aid completion of the reaction, and 85 the oils is evident from the following data on the to permit the formation of the product to be con: acid content and viscosity increase of the two oils. ducted at a lower temperature. Suitable catalysts, which may be used in concentration of m m about 0.01 to 0.2 per cent or more,.are halogens, gg 5 01 3,1 especially iodine, and some nitrogen compounds 40- n f gfffi such as high boiling amines. These catalysts p m are usually employed in such low concentrations that their presence in the product is often not timii t etfi f saafi22212213222 important. They may be removed by chemical I means when desired.

The sulphur-containing compound is suf- Example ficiently light in color that it may be blended wi From the polymer product repared from ethyl th lubricating oils in concentrations as high as ene 1 Example I the irtigfiboflmg above 10 or 15 per cent withoutimportant eifect on the color of the oil. In highly refined 'oils' the was segregated To fifty parts by weight of the olefinic'polymer was added ten parts of sulphur 553 2533 3532; fifiggig 2: ggg fand 0.02 parts iodine. This mixture was heated ciable; usually from 1 to 5 per cent of the sul- 2123 3 fiiggzag z fi gfig g zigg zgi gggffigg phurized hydrocarbon is added to lubricating oils, on This mixture was then diluted with so that the sulphur content of the oil is increased by 0.05" to 0.20 per cent or thereabouts. In paramn 011 and useda'sa'cflttmgtofl i? cutting oils, gear lubricants, and the like, the sulg g uded O gi is ii fi phur-containing' hydrocarbon may be used in m c em 0 men s o Pf an 0 concentrations as high as 20 per cent or more way be considered to l1m1t unneciegsarily the'scoge c of this invention. V Many mod cat ons can e The fonowmg examples describe specific 0 applied by those skilled in the art with'out departing from the spirit of the disclosure or scope of the accordance with my invention. 1 claims; s I

Example I I claim:

1. A sulphur-containing aliphatic hydrocarbon epared by polymerizing ethylene in the presence of an oxide of a, metal of the iron group,

one hundred parts by weight of a pelleted, pr active, reduced nickel-on-kieselguhr hydrogenaplaced in a glass tube and heated in electric C. from the total product, and reacting said polyfurnace to t r of Water cent mer fraction wth a sulphurizing agent to form a oxygen in nitrogen was passed over the catalyst sulphurized hydrbcarbon,

atsuch a rate that the theoretical amount of v 2. The process of preparing a sulphiurized hyoxygen to convert the nickel to nickel oxide had drocarbon material, which comprises subjecting been introduced at the end of four hours. The ethylene to the action of an oxide of a metal of catalyst was continuously agitated during this the iron group as a polymerization catalyst under segregating a polymer fraction boiling above 240 1 to substantially entirely straight-chain polymers, separating from eiiluents of said polymerization a polymer traction comprising polymers of at least 16 carbon atoms per molecule and chemically combining said polymer fraction with about 0.4 to 2 atoms of elementary sulphur per molecule of polymer material to produce a sulphurized hydrocarbon.

3. The process of claim 2 in which said polymer fraction is freed from compounds boiling below the lubricating-oil range prior to said combining with sulphur.

4. The process of claim 2 in which said polymerization catalyst comprises oxidized nickel.

5. The process of claim 2 in which said polymerization catalyst is prepared by subjecting an active' nickel-on-kies'elguhr hydrogenation catalyst to the oxidizing action of a gaseous atmosphere containing about 2 to 10 per cent free oxygen, the

remainder of the atmosphere being inert to said hydrogenation catalyst, until substantially all of the nickel has beenconverted to nickel oxide, said oxidizing action being effected at a temperature in the range of 400 to 700 C. I 6. A process for producing an organic compound consisting of carbon, hydrogen and sulphur in which all the carbon atoms of each molecule are in a straight chain, which comprises polymerizing ethylene in the presence or a nickel oxide polymerization catalyst to produce normal olefins of at least 16 carbon atoms per molecule, separating from eilluents 01' said polymerization a fraction containing normal oleflns of at least 16 carbon atoms per molecule, and reacting said fraction with free sulphur to produce a sulphurized hydrocarbon.

7. A process for producing an organic vcompound consisting of carbon, hydrogen and sulphur in which all the carbon atoms or each molecule are in a straight chain, which comprises polymerizing ethylene in the presence of a nickel oxide= vpolymerization catalyst to produce normal olefins of at least 16 carbon atoms per molecule, separating from effluents of said polymerization a fraction containing normal olefins of at least 16 carbon atoms per molecule, and reacting said polymer fraction with a sulphurizing agent to form a sulphurized hydrocarbon,

' JAMES A. REID.