Sulfurized additive product

Abstract

The disclosed technology relates to sulfurized additive product prepared by reacting a hydrocarbyl olefin or thiol-terminated compound with elemental sulfur under rigidly controlled and narrow reaction conditions to produce effective non-corrosive extreme pressure / antiwear additive products when incorporated into lubricants and fuels, as well as effective catalyst pre-sulfiding agents.

Description

Docket No. 4852TITLESulfurized Additive ProductBACKGROUND OF THE INVENTION

[0001] The disclosed technology relates to sulfurized additive product prepared by reacting a hydrocarbyl olefin or thiol-terminated compound with elemental sulfur under rigidly controlled and narrow reaction conditions to produce effective non- corrosive extreme pressure / anti wear additive products when incorporated into lubricants and fuels, as well as effective catalyst pre-sulfiding agents.

[0002] Sulfurized olefins have been extensively used in many lubricant applications requiring extreme pressure / anti wear activity. It is well known that many methods have been used for producing organic sulfides by treating olefins. It is also well known that many sulfurized organic compositions are useful as lubricant additives. Typically, the prior art processes provide sulfurized products having undesirably high levels of thiones, such as dithiol-thiones, and high levels of thiones in combination with various complex sulfurized mixtures. Typically also these processes, which are expensive and difficult to control, provide products having a highly disagreeable odor.

[0003] EP0201197A1 teaches the preparation of sulfurized olefins in a batch process. The ‘ 197 reference teaches that where the process has a pressure of higher than about 100 psi, not enough olefin reacts, and where the pressure is lower than about 50 psi, too much olefin reacts to satisfy the desired stoichiometric relationship of the reactants. The reference further teaches that any deviation outside of the ranges for temperature and pressure stated therein produces vastly inferior products.SUMMARY OF THE INVENTION

[0004] The disclosed technology provides a batch or continuous process yielding a faster conversion of olefin and allowing smaller process volumes by maintaining all chemicals as either liquids or supercritical fluids at elevated temperatures and pressures to provide equal to or better product than incumbent technology that uses H2S as a raw material.

[0005] This invention is directed to sulfurized products. This invention is particularly directed to a process of preparing these sulfurized products, the products so prepared and lubricating and fuel compositions containing them.Docket No. 4852

[0006] This invention relates to a process of preparing sulfurized organic additive products. These products consist essentially of mixtures of polysulfides, oligomers and dithiol-thione type compounds. The additive products are prepared under pressure by the reaction of olefinic and / or thiol-terminated compounds with elemental sulfur within a relatively narrow range of temperatures, pressures and ratio of reactants to form products containing sulfur.

[0007] The additive product is suitable for use in an oil of lubricating viscosity or grease thereof or a liquid hydrocarbyl fuel or as a catalyst pre-sulfiding agent for hydrotreating of diesel fuels, both conventional and renewable, and is prepared in a process comprising reacting in a suitable reaction zone an olefinic hydrocarbyl compound having at least one olefinic double bond or a thiol-terminated compound with elemental sulfur in a molar ratio of sulfur to olefin of from 0.4: 1 to 3.2: 1, or 1: 1 to 4: 1, or from 2: 1 to 3: 1 or from 1.5: 1 to 2.1: 1 maintaining reaction pressures of at least 565 psig at temperatures ranging from 160 to 300 °C, thereby producing a sulfurized additive product containing at least 20 weight percent of sulfur, such as 20 to 65 weight percent, or 30 to 60 weight percent sulfur, or 45 to 55 weight percent sulfur and consisting essentially of a major amount of polysulfides and a minor amount of dithiol-thione type compounds.

[0008] Sulfurized additive products as prepared herein may be employed as catalyst presulfiding agents.

[0009] Likewise, sulfurized products of enhanced extreme pressure / antiwear activity and improved corrosivity are obtained. This invention is also directed to the additive products themselves and to compositions comprising oils of lubricating viscosity or greases prepared therefrom or liquid hydrocarbyl fuels containing the same. The specific and significantly improved discreet compositions produced by the narrowly defined processing conditions disclosed herein provide thermally and oxidatively stable, non-corrosive, low-odor, extreme pressure / antiwear additives for lubricating oils, greases and fuels, or catalyst pre-sulfiding agent.

[0010] The invention in a particular aspect is directed to lubricant oil additives prepared in a one step - one pot or continuous process comprising reacting in a suitable reaction zone an olefinic hydrocarbyl compound having at least one olefinic double bond or a thiol-terminated compound with elemental sulfur.Docket No. 4852DETAILED DESCRIPTION OF THE INVENTION

[0011] Various preferred features and embodiments will be described below by way of non-limiting illustration.

[0012] A wide variety of olefinic or thiol-containing substances may be utilized in the process of the invention. This includes olefins with terminal or internal double bonds, as well as thiol-containing compounds, in either straight, branched chain or cyclic compounds.

[0013] Olefinic substances may be exemplified by ethylene, propylene, 1 -butene, cis and trans-2 -butene, isobutylene, diisobutylene, triisobutylene, pentene, cyclopentene, hexene, cyclohexene, octene, 1 -decene, etc. Also useful are diolefins, for example butadiene, isoprene, divinyl benzene, pinene, p-menthene and limonene. In general, C3 to C6 olefins or mixtures thereof are preferred and more preferably butylenes are desirable for preparing the sulfurized products embodied herein because the combined sulfur content of the product decreases with increasing carbon content and the miscibility of the product with oil is lower in the case of propylene and ethylene derivatives.

[0014] Thiol-containing compounds of course are compounds of the form R-SH in which R represents a hydrocarbyl group, and can include, for example, CH3SH [methyl mercaptan], C2H5SH [ethyl mercaptan], C3H7SH [ / / -propyl mercaptan], CH3CH(SH)CH3[2C3 mercaptan], CH2=CHCH2SH [2-propenethiol], C4H9SH [ / / -butyl mercaptan], (CH3)3CSH [ / -butyl mercaptan], C5H11SH [pentyl mercaptan], CcHsSH and the like.

[0015] In some embodiments of the invention, therefore, isobutylene is particularly preferred as the predominant olefinic reactant, but it may be employed, desirably in major proportions, in mixtures containing one or more other olefins. Moreover, substantial proportions of saturated aliphatic hydrocarbons, as exemplified by methane, ethane, propane, butane, pentane, etc. may be contained in the olefinic feed. Such alkanes are preferably present in minor proportions in most instances to avoid unnecessary dilution of the reaction since they neither react nor remain in the product, but are expelled in the off-gases or by subsequent distillation. However, such mixed feed can substantially improve the economics of the process since such streams are of lower value than a stream of, for example, relatively pure isobutylene.Docket No. 4852

[0016] Volatile olefins are often readily available in liquid form, and it is usually desirable to utilize olefinic liquids which are vaporized by the heat of reaction, as such evaporation provides a substantial cooling effect that permits the flowing of water for cooling the reactor to be reduced considerably for greater economy.

[0017] The specifically narrow molar ratio of sulfur to olefin or thiol-containing compound may range from 0.4: 1 to 3.2: 1, or 1.5 : 1 to 2. 1 : 1. In the case of butylene, the optimum ratio preferably is from 1.9: 1 to 2.25: 1.

[0018] The reaction temperature may be greater than 160 °C up to 300 °C, such as, for example from 170 to 300 °C, or greater than 180 °C, such as from 180 to 260 °C, or even greater than 190 °C, such as from 190 to 260 °C, or greater than 200 °C, such as from 200 to 260 °C. The temperature can also be greater than 230 °C, such as, for example, from 230 to 260 °C, or from 235 to 255 °C or even 240 to 250 °C, or even 240 to 245 °C or from 230 to 240 °C.

[0019] The reaction pressure is maintained throughout the reaction at or above at least 565 psig.

[0020] The reaction can be maintained at pressures of at least 565 psig for a residence time of greater than or equal to 1 minute to 60 minutes, or from greater than or equal to 1 minute to 30 minutes, or from greater than or equal to 1 minute to 15 minutes.

[0021] At the end of reaction, pressure is released and the reaction product is moved to a process to remove volatile compounds from the reaction product. Methods of removing volatile compounds are known in the art and include, for example by flash evaporation, atmospheric distillation / fractionation column, vacuum distillation / frac- tionation column, stripping, and evaporation.

[0022] The product obtained can contain 20 to 65 weight% sulfur, or 30 to 61.5 weight % sulfur, or 45 to 55 weight % sulfur, with no more than 10 to 50 weight % dithiol-thione type compounds based upon total weight of the additive product. The weight percent of sulfur to unsaturated olefin is preferably 59 to 61.5 weight percent for a C3 olefin (propylene), 52 to 54.5 weight percent for a C4 olefin (butylene) and 46.5 to 49 weight percent for a C5 olefin (pentene).

[0023] The reaction can be carried out in the absence of added H2S.

[0024] However, the reaction may also be carried out in the presence of some protic sulfur species. Protic sulfur species can include, for example, H2S and mercaptans. A ratio of protic sulfur species to olefin of about 1 : 1 to 2: 1 may be employed.Docket No. 4852

[0025] The reaction may be catalyzed with a rate accelerating catalyst. Alkylamine catalysts such as n-butylamine, di-n-butylamine, n-octylamine, triethylamine, diisopropylamine, cyclohexylamine, ethylhexanamine, ethylhexylamine, quinoline, dicyclohexylamine and the like are suitable. However, any suitable rate acceleration catalyst known in the art may be used, such as, for example, nickel molybdenum oxide, thiadiazole, quinoline and attapulgite acid clay.

[0026] In some embodiments, the process conditions allow that no rate accelerating catalyst is required. In such cases, the process may be substantially free of rate accelerating catalyst, meaning less than 100 ppm rate accelerating catalyst, or less than 50 ppm catalyst, or less than 25 ppm catalyst. In some embodiments, the process may be completely free of rate accelerating catalyst.

[0027] The reaction between the sulfur and the olefinic and / or thiol-containing compound may be conducted in a continuous reaction vessel, meaning a vessel that is in hydraulically-full flow and that is either statically or dynamically mixed operating in a laminar flow regime at the entrance of the reactor. Such continuous reaction vessels can be much smaller than batch reactors, allowing for small process volumes and less reactor footprint. The reactor is held at a constant pressure and temperature for the necessary residence time. The sulfur may be heated to a predetermined temperature in the reaction vessel prior to contacting it with the olefinic or thiol -terminated reactant, which may be chilled in order to liquify it and feed it into the reactor. Once the reaction begins, the olefin or thiol terminated compound is charged to the reaction zone substantially about as rapidly as it is consumed.

[0028] The reactor effluent can be sent to a separation vessel that removes volatile components, including but not limited to mercaptans and light ends. There can be an additional recycling step wherein the distillate from the stripping vessel is optimally recycled back to the reactor as a third feed.

[0029] The compositions hereof may include any oleaginous materials having lubri- cative properties. Especially suitable for use with the additives of this invention are liquid hydrocarbon oils of lubricating viscosity. Lubricant oils, improved of the present invention, may be of any suitable lubricating viscosity. In general, lubricant compositions may comprise any mineral or synthetic oil of lubricating viscosity or mixtures thereof. The additives prepared as disclosed herein are especially useful in greases and in automotive fluids such as brake fluids and power brake fluids,Docket No. 4852 transmission fluids, power steering fluids, various hydraulic fluids and gear oils and in liquid hydrocarbyl fuels as well as in Industrial fluids, like industrial gear oils and turbine fluids and the like.

[0030] In instances where synthetic oils are desired in preference to refined petroleum or mineral oil they may be employed alone or in combination with a mineral oil. They may also be used as the vehicle or base of grease compositions. Typical synthetic lubricants include polyisobutylene, polybutenes, hydrogenated polydecenes, polypropylene glycol, polyethylene glycol, trimethylol propane esters, neopentyl and pentaerythritol esters of carboxylic acids, di(2-ethylhexyl) sebacate, di(2- ethylhexyl) adipate, dibutyl phthalate, fluorocarbons, silicate esters, silahes, esters of phosphorus-containing acids, liquid ureas, ferrocene derivatives, hydrogenated mineral oils, chain-type polyphenols, siloxanes and silicones (polysiloxanes), alkylsubstituted diphenyl ethers typified by a butyl-substituted bis(p-phenoxy phenyl) ether, phenoxy phenylethers, dialkylbenzenes, etc.

[0031] Generally, the lubricants and fuels of the present invention contain an amount of the sulfurized product effective to improve extreme pressure properties and antiwear and oxidation characteristics. Normally this amount will be 0.01 to 20% and preferably 0.01 to 10% of the total weight of the lubricant.

[0032] The invention also contemplates the use of other additives in combination with the sulfurized additive product. Such additives include, for example, detergents and dispersants of the ash-producing or ashless type, corrosion-inhibiting agents, auxiliary oxidation-inhibiting agents, pour point depression agents, auxiliary extreme pressure agents, color stabilizers and anti-foam agents.

[0033] The sulfurized additive product can also be employed as a catalyst pre-sulfid- ing agent. Hydrotreating catalysts require activation to become catalytically active, a process commonly known as sulfiding or presulfiding. This process entails converting initially catalytically inactive metal oxides into active metal sulfides, a critical step in enhancing the catalyst's performance in hydroprocessing. The established sulfiding procedures date back to the early 1960s and generally involve four essential components: (1) a sulfur-bearing agent, (2) the catalyst, (3) hydrogen, and (4) heat. The sulfurized additive product of the invention can be employed as a sulfur-bearing agent in a sulfiding or presulfiding process for catalyst used in hydroprocessingDocket No. 4852 applications, including for example, metal containing catalysts, such as molybdenum, tungsten, cobalt, and nickel.

[0034] The amount of each chemical component described is presented exclusive of any solvent or diluent oil, which may be customarily present in the commercial material, that is, on an active chemical basis, unless otherwise indicated. However, unless otherwise indicated, each chemical or composition referred to herein should be interpreted as being a commercial grade material which may contain the isomers, by-products, derivatives, and other such materials which are normally understood to be present in the commercial grade.

[0035] As used herein, the term "hydrocarbyl" or "hydrocarbyl group" is used in its ordinary sense, which is well-known to those skilled in the art. Specifically, it refers to a group having a carbon atom directly attached to the remainder of the molecule and having predominantly hydrocarbon character. Examples of hydrocarbyl groups include:

[0036] hydrocarbon substituents, that is, aliphatic (e.g., alkyl or alkenyl), alicyclic (e.g., cycloalkyl, cycloalkenyl) substituents, and aromatic-, aliphatic-, and alicyclic- substituted aromatic substituents, as well as cyclic substituents wherein the ring is completed through another portion of the molecule (e.g., two substituents together form a ring);

[0037] substituted hydrocarbon substituents, that is, substituents containing non-hy- drocarbon groups which, in the context of this invention, do not alter the predominantly hydrocarbon nature of the substituent (e.g., halo (especially chloro and fluoro), hydroxy, alkoxy, mercapto, alkylmercapto, nitro, nitroso, and sulfoxy);

[0038] hetero substituents, that is, substituents which, while having a predominantly hydrocarbon character, in the context of this invention, contain other than carbon in a ring or chain otherwise composed of carbon atoms and encompass substituents as pyridyl, furyl, thienyl and imidazolyl. Heteroatoms include sulfur, oxygen, and nitrogen. In general, no more than two, or no more than one, non-hydrocarbon substituent will be present for every ten carbon atoms in the hydrocarbyl group; alternatively, there may be no non-hydrocarbon substituents in the hydrocarbyl group.

[0039] It is known that some of the materials described above may interact in the final formulation, so that the components of the final formulation may be different from those that are initially added. For instance, metal ions (of, e.g., a detergent)Docket No. 4852 can migrate to other acidic or anionic sites of other molecules. The products formed thereby, including the products formed upon employing the composition of the present invention in its intended use, may not be susceptible of easy description. Nevertheless, all such modifications and reaction products are included within the scope of the present invention; the present invention encompasses the composition prepared by admixing the components described above.EXAMPLES

[0040] CONTINUOUS Examples (“El”): The sulfur and isobutylene feeds were adjusted to achieve a molar ratio of sulfur to isobutylene of 2. 1 : 1. The sulfur feed was preheated to 135 °C and introduced at a rate of 66.20 g / min under a pressure of 800 psig, while the isobutylene feed was similarly preheated to 135 °C and fed at 56.40 g / min under the same pressure. Both feeds entered a tubular flow reactor equipped with static mixers to ensure proper mixing, with a total reaction volume of 1.95 liters. At these flow rates, the residence time within the reaction zone was 15 minutes. Upon entering the reaction zone, the reactive mixture (sulfur and isobutylene) was further heated to 220 °C and maintained at this temperature throughout the reaction zone. The mixture then passed through a cooling zone, where it was cooled down to 150 °C. Next, it flowed through a pressure-regulating valve that maintained a constant back pressure of 800 psig across the reaction and cooling zones. The cooled mixture was directed to the top of a separation column operating at 120 °C under a vacuum of 500 mmHg to remove unreacted isobutylene, hydrogen sulfide (H2S), and low-molecu- lar-weight polysulfides. During this step, nitrogen was continuously introduced from the bottom of the column (counterflow) at a rate of 8 SCFH to assist in disengaging volatiles from the reactive mixture. The final product exited from the bottom of the column into a product tank, while volatiles were removed from the top and sent to a condenser operating at 0 °C, which condensed low-molecular-weight polysulfides. These were collected in a receiving tank, and non-condensable components, including isobutylene and H2S, were vented to a caustic scrubber and subsequently to a fume incinerator.

[0041] CONTINUOUS Examples (“E2”): Run according to El, except that the reaction was maintained for a residence time of 10 minutes.Docket No. 4852

[0042] CONTINUOUS Examples (“E3”): Run according to El, except that the reaction temperature was held at 205 and the reaction pressure was maintained at 600 psig for a residence time of 20 minutes.

[0043] BATCH Examples (“Bl”): The charges of sulfur and isobutylene were adjusted to achieve a molar ratio of sulfur to isobutylene of approximately 2.1 : 1. A charge of 8.5 g of isobutylene was introduced into vessel #1 which has a volume of 32 mL. After that, the vessel was sealed, pressurized to 1000 psig, and heated to 250 °C. Separately, 10.0 g of sulfur was introduced into vessel #2 which has a volume of 28 mL. Similarly, vessel #2 was pressurized to 1000 psig and heated to 250 °C. Vessel #2 functioned as the primary reaction vessel. To initiate the reaction, the isobutylene from vessel #1 was transferred via pressure into vessel #2, combined with the sulfur charge, and mixed using a magnetic stirrer. The resulting reactive mixture was maintained at 250 °C for a period of 30 minutes. The pressure of the vessel was held at 1000 psig during the reaction. Next, the reactive mixture was transferred to vessel #3 which has a volume of 34 mL and served as a thermal quench vessel. The mixture was cooled to ambient temperature. Excess pressure was vented from vessel #3, and the final product was then collected for analysis.

[0044] Comparative Example 1 (“CE1”): During the initial 10 minutes of the reaction, the pressure decreased from 1000 psig to 150 psig, after which it remained constant at 150 psig for the remaining 20 minutes.

[0045] Comparative Example 2 (“CE2”) - Run according to Example 1 of EP0201197A1 filed April 4, 1986 by Applicant Mobil Oil Corporation. That is, the reaction used a molar ratio of sulfur to isobutylene of 2.0: 1. A 1 -gallon stirred autoclave (reactor) was charged with 1,344 g sulfur and 1.2 g n-butylamine (0.05% of the total charge). The reactor was sealed and purged three times with nitrogen to remove oxygen. The reactor was then charged with 1,176 g isobutylene under pressure. The reactor agitator was activated and heated to 160°C and held at that temperature until the pressure dropped from its maximum of 700 psi to below 75 psi. The reactor was cooled to 100°C and vented to a caustic scrubber. The product was then sparged with nitrogen for three hours at 100°C to remove gaseous contaminates, cooled to less than 30°C and then filtered through diatomaceous earth. The product yield was about 99% of the total reactants charged.

[0046] The residence times for the reactions are provided in the table below.Docket No. 4852

[0047] Each of the documents referred to above is incorporated herein by reference. The mention of any document is not an admission that such document qualifies as prior art or constitutes the general knowledge of the skilled person in any jurisdiction.Except in the Examples, or where otherwise explicitly indicated, all numerical quantities in this description specifying amounts of materials, reaction conditions, molecular weights, number of carbon atoms, and the like, are to be understood as modified by the word "about." It is to be understood that the upper and lower amount, range, and ratio limits set forth herein may be independently combined. Similarly, the ranges and amounts for each element of the invention can be used together with ranges or amounts for any of the other elements. As used herein, the expression "consisting essentially of" permits the inclusion of substances that do not materially affect the basic and novel characteristics of the composition under consideration.

Claims

Docket No. 4852What is claimed is:

1. A process for making a sulfurized additive product comprising reacting in a suitable reaction zone 1) an olefinic hydrocarbyl compound having at least one olefinic double bond, or thiol-terminated compound, with 2) elemental sulfur, in a molar ratio of sulfur to olefin or thiol-terminated compound of from 0.4: 1 to 3.2:1 while maintaining reaction pressures of at least 565 psig at temperatures ranging from 170 to 300°C, followed by removal of volatile compounds from the reaction product, thereby producing a sulfurized additive product containing sulfur and consisting essentially of a major amount of polysulfides and a minor amount of dithiol-thione type compounds.

2. The process of claim 1, wherein the additive product contains 20 to 65 weight percent sulfur.

3. The process of claim 1, wherein said process is a one step - one pot process.

4. The process of claim 1, wherein said process is a continuous process.

5. The process of claim 1, wherein the temperature varies from 190 to 260°C with a residence time of 30 minutes to greater than or equal to 1 minute.

6. The process of claim 1, wherein the temperature varies from 205 to 260° C with a residence time of 15 minutes to greater than or equal to 1 minute.

7. The process of claim 1, wherein the temperature varies from 220 to 260° C with a residence time of 5 minutes to greater than or equal to 1 minute.

8. The process of any previous claim, wherein the process is carried out without a rate accelerating catalyst.

9. The process of any previous claim, wherein said process is carried out in the presence of a rate accelerating catalyst.

10. The process of claim 9, wherein said rate accelerating catalyst is selected from the group consisting of nickel molybdenum oxide, thiadiazole, n-butylamine, di- n-butylamine, n-octylamine, triethylamine, diisopropylamine, cyclohexylamine, di cyclohexylamine, ethylhexanamine, ethylhexyl amine, quinoline and attapulgite acid clay.

11. The process of claim 1, wherein the olefin is selected from the group consisting of ethylene, propylene, 1-butene, cis and trans-2-butene, isobutylene, diisobutylene, triisobutylene, pentene, cyclopentene, hexene, cylcohexene, octene, 1-de- cene, butadiene, isoprene, divinyl. benzene, pinene, p-menthene and limonene.Docket No. 485212. The process of claim 11, wherein the olefin is isobutylene.

13. The process of claim 1, wherein a protic sulfur species is included in the reaction at a ratio of protic sulfur species to olefin of about 1 : 1 to 2: 1.

14. The process of claim 1, wherein the product is prepared in the absence of added H2S.

15. A lubricant composition comprising a major amount of an oil of lubricating viscosity or grease prepared therefrom and a minor amount sufficient to impart extreme pressure, antiwear activity and anticorrosion characteristics thereto of an additive product prepared in a process according to any one of claims 1 to 14.

16. The lubricant composition of claim 15, wherein said major amount is an oil of lubricating viscosity.

17. The lubricant composition of claim 15, wherein said oil is selected from mineral oils, synthetic oils and mixtures thereof.

18. A method of catalyst pre-sulfiding comprising treating a metal catalyst with a sulfurized additive product, wherein the sulfurized additive product was prepared according to the process of claim 1.

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