JP2005511814A - Use of alkylated naphthalenes as synthetic lubricant bases and alkylated naphthalenes to improve the antioxidant performance of other lubricant base oils - Google Patents

Abstract

  The present invention relates to the usefulness of alkylated methylnaphthalene and alkylated methylnaphthalene in lubricant bases. In particular, the alkylated methylnaphthalene of the present invention has surprisingly excellent thermal and oxidation properties and can be used to improve the performance characteristics of other lubricant base oils.

Description

  The present invention relates to the utility of alkylated methylnaphthalene and alkylated methylnaphthalene in synthetic lubricant base oils.

  Alkyl aromatic fluids have been proposed for use as a specific type of functional fluid where good thermal and oxidation properties are required. For example, Patent Document 1 (Yoshida) has excellent thermal stability and oxidation stability, low vapor pressure and flash point, good fluidity and high heat transfer capacity, and other characteristics, thereby Monoalkylated naphthalene is described as suitable for use as an oil. U.S. Patent No. 6,057,049 (Dressler) describes the use of a mixture of monoalkylated and polyalkylated naphthalenes as a base for synthetic functional oils. US Pat. Nos. 5,099,028 and 4,096,009 to Pellegrini describe the use of alkyl aromatic compounds as trans oils.

  Alkylated naphthalenes are usually acidic alkylation catalysts such as Friedel-Craft catalysts such as acid clay described in Patent Document 1 by Yoshida or Patent Document 2 by Dressler, and patents by Pellegrini. It is produced by alkylating naphthalene or substituted naphthalene in the presence of a Lewis acid such as aluminum trichloride described in Document 3 and Patent Document 4. The use of a catalyst described as a decayed silica-alumina zeolite for alkylation of aromatic compounds such as naphthalene is disclosed in US Pat. The use of various zeolites, including intermediate pore size zeolites such as ZSM-5, and large pore size zeolites such as zeolite L and ZSM-4, for the alkylation of various monocyclic aromatic compounds such as benzene, It is disclosed in US Pat.

  In formulating functional fluids based on alkyl naphthalenes, the preferred alkyl naphthalenes have been found to be mono-substituted naphthalenes since mono-substituted naphthalenes provide the best combination of properties in the final product. Monosubstituted naphthalenes have been said to have less benzylic hydrogen than the corresponding disubstituted or polysubstituted naphthalenes, have better oxidative stability and thus form better functional fluids and additives. Furthermore, monosubstituted naphthalenes have kinematic viscosities within the desired range of about 5-8 cSt (at 100 ° C.) when working with alkyl substituents of about 14-18 carbon chain length. Much work has been done to improve the selectivity to the desired monoalkylated naphthalene.

  U.S. Pat. No. 6,057,096 by Ashjian et al. Teaches the use of zeolites containing bulky cations. This patent is incorporated herein by reference. For example, the use of USY containing cations having a radius of at least about 2.5 angstroms increases the selectivity to the desired monoalkylated product. Suitable zeolites include zeolites comprising a hydrated cation of a Group IA metal, a divalent cation (especially a Group IIA metal) and a rare earth cation.

  In US Pat. No. 6,057,049 to Le et al., Desirable properties of alkylated naphthalene fluids with higher alpha: beta ratios, including improved thermal and oxidative stability, are discussed. This patent is incorporated herein by reference. Le et al. Have found that several parameters affect the alpha: beta ratio of alkylated naphthalene products, including zeolite steaming, reduction of alkylation temperature or use of acid-treated clay.

U.S. Patent No. 6,099,049 by Dwyer et al. Discloses the effect of co-feed water for alkylation reactions when using large pore zeolite catalysts such as zeolite Y. This patent is incorporated herein by reference. Patent Document 10 and Patent Document 11, a similar alkylation process using MCM-41 and mixtures H / NH ₄ catalyst respectively are disclosed. These patents are incorporated herein by reference.

  As mentioned above, the prior art teaches that mono-substituted naphthalene is the most desirable component as a synthetic lubricant base with optimized thermal stability, oxidative stability and viscosity characteristics. Thus, the prior art teaches processes for improving selectivity and achieving the desired monoalkylated product. Dialkyl naphthalene was thought to have poor lubricant properties because dialkylation prevents the naphthalene ring from neutralizing oxygen, peroxides or radicals. Alkylated naphthalenes with dialkyl or trialkyl components were considered to have poor thermal and oxidative stability.

U.S. Pat. No. 4,714,794 U.S. Pat. No. 4,604,491 U.S. Pat. No. 4,211,665 U.S. Pat. No. 4,238,343 US Pat. No. 4,570,027 U.S. Pat. No. 4,301,316 US Pat. No. 5,034,563 US Pat. No. 5,177,284 US Pat. No. 5,191,135 US Pat. No. 5,191,134 US Pat. No. 5,457,254 U.S. Pat. No. 4,016,218 US Pat. No. 4,861,932 US Pat. No. 4,954,325 US Pat. No. 5,362,697 US Pat. No. 5,236,575 US Pat. No. 5,371,310 US Pat. No. 3,402,966 US Pat. No. 3,923,192 US Pat. No. 3,449,070 US Pat. No. 3,354,078 US Pat. No. 4,663,492 US Pat. No. 4,594,146 US Pat. No. 4,522,929 US Pat. No. 4,429,176 J. et al. In Catalysis 67, 218-222 (1981), Frilette et al. “Shape-Selective Catalysis in Industrial Applications” by Chen et al., Chemical industries, vol. 36, Marcel Dekker Inc., New York, 1989, ISBN 0-8247-7856-1. Hölderich et al., Angew. Chem. Int. Ed. Engl. 27, 226-246 (1988), pp. 226-229 “Catalytic Cracking, Catalysts, Chemistry and Kinetics”, Chemical Industries, vol. 25, Marcel Dekker, New York, 1986, ISBN 0-8247-7503-8. J. et al. Catalysis, 4,527 (1965) J. et al. Catalysis, 6, 278 (1966) J. et al. Catalysis, 61, 395 (1980)

  Now, dialkylnaphthalene, trialkylnaphthalene or tetraalkylnaphthalene, especially alkylmethylnaphthalene, contrary to the teaching of the technology, often has excellent thermal and oxidative properties which are significantly better than mono-substituted naphthalene. It's been found.

  The present invention thus broadens the range of raw materials that can be used to produce synthetic bases and establishes that alkylmethylnaphthalene has better oxidative stability than known alkylnaphthalene fluids.

（式中、Ｒ^１およびＲ^２は、Ｈ、メチル基、エチル基、ｎ−プロピル基、ｎ−ブチル基またはｔ−ブチル基であり、Ｒ^３およびＲ^４は、炭素原子数約６〜約２４のアルキル基であり、ｘは０〜約２であり、ｙは０〜約４であり、但し、Ｒ^１とＲ^２の少なくとも一方はＨでなく、ｘとｙの少なくとも一方は０でない）
の化合物または化合物の混合物からなる群から選択されるアルキル化ナフタレンを含有する前記基油を含む基油を含む。 The present invention includes dialkylnaphthalenes, trialkylnaphthalenes or tetraalkylnaphthalenes, preferably dialkylnaphthalenes, which have utility as synthetic lubricant bases, formulations or as additives for other base fluids or liquid fuels. . The present invention is a base oil comprising a mixture of monoalkylated naphthalene and polyalkylated naphthalene, the improvement being at least 20% by weight of the following formula (I):

Wherein R ¹ and R ² are H, a methyl group, an ethyl group, an n-propyl group, an n-butyl group or a t-butyl group, and R ³ and R ⁴ have about 6 to about carbon atoms. 24 alkyl groups, x is 0 to about 2, and y is 0 to about 4, provided that at least one of R ¹ and R ² is not H and at least one of x and y is not 0)
A base oil comprising said base oil containing an alkylated naphthalene selected from the group consisting of a compound or a mixture of compounds.

Preferably, only one of R ¹ and R ² is an alkyl group, the other is H, and most preferably ^one of R ¹ and R ² is H and the other is a methyl group.

  The compounds of formula (I) have unexpectedly superior thermal and oxidation properties, especially when compared to monosubstituted naphthalenes. The term “monosubstituted naphthalene” as used herein generally refers to naphthalene having a single substituent, such as an alkyl group having from about 6 to about 24 carbon atoms.

  Another aspect of the invention relates to a method for improving the oxidative stability of a lubricant comprising the step of adding a base oil comprising a compound of formula (I) to the lubricant.

（式中、Ｒ^１およびＲ^２は、Ｈ、メチル基、エチル基、プロピル基またはブチル基であり、Ｒ^３およびＲ^４は、炭素原子数約６〜約２４のアルキル基であり、ｘは０〜約２であり、ｙは０〜約４であり、但し、Ｒ^１とＲ^２の少なくとも一方がはＨでなく、ｘとｙの少なくとも一方は０でない）
の化合物を含み、約２００分より長いＲＢＯＴ値を有する基油を、前記潤滑剤に添加する工程を含む方法に関する。 Therefore, this method is a method for improving the oxidative stability of a lubricant having an RBOT value of about 200 minutes or less, which has the following formula (I):

Wherein R ¹ and R ² are H, methyl group, ethyl group, propyl group or butyl group, R ³ and R ⁴ are alkyl groups having from about 6 to about 24 carbon atoms, and x is 0 to about 2, and y is 0 to about 4, provided that at least one of R ¹ and R ² is not H and at least one of x and y is not 0)
And a base oil having an RBOT value greater than about 200 minutes is added to the lubricant.

  As used herein, “alkylated methylnaphthalene” means a methyl group at one or two positions of the naphthalene ring and at least one of about 6 to about 24 carbon atoms bonded to another position of the ring. A naphthalene compound having another alkyl group. Further, all values stated herein include the ranges and specific numerical values for all combinations and subcombinations indicated therein.

  Starting materials for the preparation of compounds of formula (I) are substituted naphthalenes which may contain one or more short-chain alkyl groups containing up to about 8 carbon atoms, such as methyl, ethyl, propyl or butyl groups It is. Preferably, the starting material comprises 1-methylnaphthalene, 2-methylnaphthalene or a mixture of either of these two ratios. For example, 1-methylnaphthalene and 2-methylnaphthalene are a heavy fraction of aromatic reformate stream (greater than 10 carbon atoms) in coke liquor, heavy bottom oil stream from toluene disproportionation process. Or in a heavy fraction from a catalytic cracking process (such as a light cycle oil from an FCC process). A feed stream with a high 2-methylnaphthalene content (such as a feed stream from a highly selective toluene disproportionation process) is generally alkylated when compared to a feed stream containing a large amount of 1-methylnaphthalene. Methyl naphthalene products are preferred because they have better oxidative stability and the alkylation process tends to be more efficient. Furthermore, the starting material may comprise a mixture of methylnaphthalene and naphthalene.

  Alkylating agents that may be used to alkylate the substituted naphthalene include any aliphatic or aromatic organic compound having one or more effective alkylating aliphatic groups capable of alkylating the substituted naphthalene. The alkylatable group itself should have at least about 6 carbon atoms, preferably at least 8 carbon atoms, more preferably at least about 12 carbon atoms. For the production of functional fluids and additives, the alkyl groups on naphthalene preferably have from about 12 to about 24 carbon atoms, with about 14 to about 18 carbon atoms being particularly preferred. A preferred class of alkylating agents are olefins having the requisite number of carbon atoms, such as dodecene, tetradecene, pentadecene, hexadecene, heptadecene, octadecene, nonadecene and branched analogs thereof.

  In a preferred embodiment, the alkylating agent is an internal olefin (such as 2- or 3-tetradecene), an alpha (ie 1-) olefin, a vinylidene olefin (2-methyl-1-tetradecene, 2,3,3-trimethyl- 1-butene, 2,4,4-trimethyl-1-pentene or 2,4,4-trimethyl-2-pentene). Alpha olefins and linear internal olefins are most readily available.

Mixtures of olefins may also be used in the present invention, for example mixtures of C ₁₂ -C ₂₀ olefins or C ₁₄ -C ₁₈ olefins. Branched alkylating agents are also useful, especially oligomerized olefins such as trimers, tetramers or pentamers of light olefins such as ethylene, propylene and butylene. Other useful alkylating agents that may be used include alcohols such as hexadecanol, heptadecanol, octadecanol, nonadecanol, dodecanol and doundecanol. Alkyl halides such as hexadecyl chloride, octadecyl chloride, dodecanyl chloride and higher homologues may also be used in the present invention.

  Previous prior art documents relating to the production of alkyl naphthalenes have emphasized the production of large amounts of monoalkyl naphthalene. In the present invention, a dialkylnaphthalene (for example, a methyl group at the 1-position or the 2-position and an alkyl group having about 6 carbon atoms bonded to another position of the ring) is a group in which one of the alkyl groups is a methyl group or an ethyl group. Can be produced consistently. Dialkyl products can be achieved by carefully selecting the starting materials and controlling the first alkyl group present in the naphthalene ring.

  The alkylation reaction between the substituted naphthalene and the alkylating agent is performed in the presence of an alkylation catalyst. Typically, the catalyst comprises a zeolitic catalyst containing a cation of a defined radius. The molecular size of the alkylated product requires a relatively large pore size in the zeolite in order for the product to leave the zeolite, which also tends to reduce diffusion limitations due to long chain alkylating agents. Large pore zeolites are the most useful zeolite catalysts for this purpose. However, as discussed below, intermediate pore size zeolites that are less constrained may also be used. Also useful are acid clay materials such as “Fitrol” 20, 22, and 24 sold by Englehard Co.

  Examples of the large pore diameter zeolite include faujasite, synthetic faujasite (zeolites X and Y), zeolite L, ZSM-4, ZSM-18, ZSM-20, mordenite and offretite. As described in Non-Patent Document 1, such zeolites are characterized by the presence of an oxygen 12-membered ring system in the molecular structure and the presence of pores having a minimum dimension of at least 7.4 angstroms. See also Non-Patent Document 2 and Non-Patent Document 3. Large pore zeolites can also be characterized by a “constraint index” (CI) of 2 or less, most often 1 or less. A method for determining CI is described in US Pat. The significance of this index is described in Patent Document 13. See this document for a description of the test procedures and their interpretation.

  Zeolites with a 10-membered oxygen structure and generally considered as intermediate pore size zeolites can also be effective catalysts for this alkylation reaction if the structure is not too constrained It is. Zeolites such as ZSM-12 (CI is 2) may be effective catalysts for alkylation reactions. Zeolite identified as MCM-22 is also a useful catalyst for this reaction and is described in US Pat. This patent is incorporated herein by reference. Furthermore, MCM-56 described in Patent Document 15 may also be used. This patent is incorporated herein by reference. Zeolites with a CI of about 3 or less are generally useful catalysts. However, the activity may vary depending on the choice of alkylating agent, in particular the chain length of the alkylating agent (which is a factor that imposes diffusion restrictions on the choice of zeolite). Other useful catalysts include MCM-49 described in US Pat. These patents are incorporated herein by reference.

  Another useful zeolite according to the present invention includes ultrastable Y, commonly referred to as USY. When this material contains hydrated cations, this material catalyzes alkylation with good selectivity and good yield. Zeolite USY is a commercial material available in large quantities as a catalyst for petroleum cracking. Zeolite USY is produced by stabilization of zeolite Y by repeated ammonium exchange and controlled steaming procedures. Processes for the production of the zeolite USY are described in US Pat. Nos. 5,099,086 (McDaniel), US Pat. See also Non-Patent Document 4 by Wojciechowski for a description of zeolite USY, its preparation and properties.

  The most preferred zeolites according to the present invention include USY, MCM-22, MCM-49 and MCM-56.

  In addition, other catalysts that may be used in the present invention include zeolites having both ammonium and proton species associated with the exchangeable sites of the zeolite. Such a catalyst is disclosed in US Pat. This patent is incorporated herein by reference. As also disclosed in US Pat. No. 6,057,059, the selected zeolite catalyst preferably contains a limited amount of one or more rare earths.

  The catalyst of the present invention may be complexed with a matrix material or binder that can withstand the temperature and other conditions used in the alkylation process. Such materials include active and inert materials, as well as synthetic or natural zeolites, and inorganic materials such as clay, silica or silica-alumina. The latter may be natural or take the form of a gelatinous precipitate or gel comprising a mixture of silica and metal oxide. The use of active materials in combination with zeolites can change the conversion and / or selectivity of the catalyst. The inert material functions properly as a diluent to control the conversion so that the alkylated product can be obtained economically and orderly without using other means to control the rate of reaction. To do. Binders that may be introduced to improve the crush strength and other physical properties of the catalyst under commercial alkylation operating conditions include natural clay (eg bentonite and kaolin), silica, alumina, zirconia and their Examples include, but are not limited to, mixtures.

The alpha value of the zeolite is an approximate indicator of the catalytic cracking activity of the catalyst compared to the standard catalyst. In the alpha test, the relative rate constant of the test catalyst based on a standard catalyst (rate constant (normal hexane conversion rate per unit time, per unit catalyst volume) = 0.016 sec ⁻¹ ) regarded as alpha value = 1 is used. give. The alpha test is described in Patent Document 21, Non-Patent Document 5, Non-Patent Document 6, and Non-Patent Document 7. See these for test descriptions.

  In general, zeolites with high alpha values in the range of about 10 to about 1000 are preferred for use in the present invention. Most catalysts have alpha values greater than 30, and some zeolites such as Y and USY have high initial alpha values of about 1000 or less. For purposes of the present invention, alpha values of about 10 or greater are effective in the alkylation process. MCM-22, MCM-49 and MCM-56 generally have a stable and high alpha value of about 40 to about 500 and are particularly suitable for fixed bed continuous operation.

  The stability of the alkylation catalyst of the present invention can be enhanced by steaming. U.S. Patent Nos. 6,099,036, 5,836, and 5,834, are incorporated herein by reference and describe conditions for vapor stabilization of a zeolite catalyst that can be used to vapor stabilize the zeolite catalyst. doing.

  The alkylation process of the present invention is suitable for organic reactants, such as an alkylatable methylnaphthalene compound and an alkylating agent, under suitable alkylation conditions (eg, in a flow reactor containing a fixed bed of the catalyst composition). In the reaction zone) in contact with the catalyst. The preferred starting material methylnaphthalene is used in the description of the alkylation conditions.

  Alkylation reaction conditions typically include a temperature of about 100 ° C to about 400 ° C, preferably about 150 ° C to about 250 ° C. In general, the reaction rate may be too slow at temperatures below 100 ° C., and temperatures above 300 ° C. may promote undesired side reactions that can reduce product properties and yield.

  Typical reaction pressures include pressures of about 0.1 to about 100 atmospheres, preferably about 1 to about 30 atmospheres. The necessary pressure may be maintained by pressurizing an inert gas (preferably nitrogen).

  Typical reaction times are about 0.5 to about 100 hours, preferably about 2 to about 30 hours. The reaction time depends on the temperature and the amount of catalyst used in the process. In general, higher reaction temperatures and higher catalyst inputs facilitate faster reaction rates.

  A typical methylnaphthalene compound / alkylating agent molar ratio (MN: O) capable of alkylation is from about 1: 3 to about 10: 1, preferably from about 1: 2 to about 3: 1.

  Generally, the amount of catalyst charged is from about 0.1% to about 10% by weight in the slurry reactor. A low catalyst input can cause longer reaction times, and a high catalyst input can cause clogging of the filter during the catalyst removal process and can be uneconomical to operate. Preferably, the catalyst charge is from about 0.5% to about 5% by weight. The reaction may be carried out in a fixed bed continuous operation where the catalyst takes the form of pellets or extrudates and is packed in a tubular reactor heated to the desired temperature. The feedstock is introduced at a specific hourly space hourly space velocity (WHSV) in the range of about 0.1 to about 20, preferably about 0.5 to about 5, to achieve high conversion.

  Preferred reaction conditions include a temperature in the range of about 150 to about 250 ° C., a pressure of about 1 to about 30 atmospheres, a reaction time of about 2 to about 30 hours, a MN: O molar ratio of about 1: 2 to about 3: 1. And about 1% to about 5% by weight of the preferred catalyst charge in the slurry reactor (or about 0.2 to about 4 WHSV in fixed bed continuous operation).

  The reactant may be either in the gas phase or liquid phase, pure (ie, without intentional mixing) or diluted with other materials, or the reactant may be a carrier such as hydrogen, nitrogen, etc. It is possible to contact the catalyst composition with the aid of a gas or diluent. Alkylation is typically performed as a batch-type reaction using a closed pressurized stirred reactor containing an inert gas seal system or in semi-continuous or continuous operation using a fixed bed catalyst system or a moving bed catalyst system. Is possible.

  In the preparation of the compound of formula (I), a certain amount of alkylating olefin dimer is co-produced. The bases herein, including formula (I), whether used as bases or as co-bases, typically contain less than 1% by weight of dimer.

  The compounds of formula (I) are characterized by particularly good oxidative and thermal stability. The compound of formula (I) may be separated from the reaction mixture by stripping off the unreacted alkylating agent and the compound of formula (I) in a conventional manner. It has also been found that the stability of the alkylation product can be improved by filtration with activated carbon and alkaline treatment (to remove impurities, especially acidic by-products formed by oxidation during the course of the reaction). . The alkali treatment is carried out by filtration over a solid alkaline material, preferably calcium carbonate (lime).

（式中、Ｒ^１およびＲ^２は、Ｈ、メチル基、エチル基、プロピル基またはブチル基であり、Ｒ^３およびＲ^４は、炭素原子数約６〜約２４のアルキル基であり、ｘは０〜約２であり、ｙは０〜約４であり、但し、Ｒ^１とＲ^２の少なくとも一方はＨでなく、ｘとｙの少なくとも一方は０でない）
で表される化合物を含む。 The synthetic lubricant base of the present invention has the following formula (I):

Wherein R ¹ and R ² are H, methyl group, ethyl group, propyl group or butyl group, R ³ and R ⁴ are alkyl groups having from about 6 to about 24 carbon atoms, and x is 0 to about 2, and y is 0 to about 4, provided that at least one of R ¹ and R ² is not H and at least one of x and y is not 0)
The compound represented by these is included.

In a preferred embodiment, either R ¹ or R ² is H and the other is an alkyl group. Most preferably, either R ¹ or R ² is H and the other is a methyl group. Accordingly, 1- or 2-methylnaphthalene or mixtures thereof are preferred starting materials. In general, a mixture rich in 2-methylnaphthalene is more preferable. This is because 2-methylnaphthalene is more reactive than 1-methylnaphthalene and the alkylation product of 2-methylnaphthalene has better stability than the alkylation product of 1-methylnaphthalene. As mentioned above, the heavy bottoms stream from the highly shape selective toluene disproportionation process is typically rich in 2-methylnaphthalene and is particularly suitable for use in the present invention.

In preferred embodiments, R ³ and R ⁴ also include alkyl groups having from about 6 to about 24 carbon atoms, more preferably from about 8 to about 18 carbon atoms. Representative R ³ group and R ⁴ group each include a hexyl group, a heptyl group, an octyl group, a nonyl group, an isooctyl group, a 2-ethylhexyl group, a decyl group, and an undecyl group each optionally having a linear or branched alkyl group. , Tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group and octadecyl group.

The sum of x and y is preferably from about 1 to about 3. More preferably, the synthetic oil comprises a dialkylnaphthalene in which the sum of x and y is 1, R ¹ is H, and R ² is a methyl group. Synthetic oils may include highly alkylated naphthalenes where the sum of x and y is greater than 1, ie, about 2-3. When using a mixture of compounds of formula (I), the ratio of dialkylnaphthalene / trialkylnaphthalene or tetraalkylnaphthalene may be about 3 to about 1, more preferably about 25 to about 1. The amount of dialkylnaphthalene product relative to the tri- or tetraalkylnaphthalene product may be controlled by changing the methylnaphthalene / alkylating agent olefin ratio in the feed, the type of catalyst and / or the reaction temperature. Usually, a lower methylnaphthalene / olefin ratio (higher olefin content) favors the production of trialkylated or tetraalkylated naphthalene.

  The compounds of formula (I) described herein exhibit excellent thermal and oxidation properties, which make the compounds particularly suitable for use in lubricant base oils. Such properties were generally superior and surprising, especially when compared to monosubstituted naphthalenes. The compounds of formula (I) can be characterized, for example, by oxidative stability, viscosity and pour point. Generally speaking, the thermal and oxidation properties of the compounds of formula (I) depend on the alkylation conditions (including, for example, the starting material / alkylating agent ratio, the reaction temperature and the particular alkylating agent used). May be different.

  The compound of formula (I) may be used to improve the oxidative stability of the lubricant. For example, the oxidative stability of compounds of formula (I) as measured under a rotary bomb oxidation test (RBOT) (ASTM D2272) is generally greater than about 200 minutes, more preferably greater than about 500 minutes. In preferred embodiments, the RBOT value is between about 500-1500 minutes, more preferably between 700 minutes and 1200 minutes. All values stated herein include all combinations and subcombinations of ranges and specific numerical values set forth therein.

  Further, the kinematic viscosity of the compound of formula (I) at 100 ° C. is about 2 to about 30 cS, more preferably about 3 to about 20 cS, and the viscosity index (VI) value is about 50 to about 180, preferably Is greater than about 60. The pour point of the compound of formula (I) is about 0 to about −60 ° C., more preferably −10 to about −55 ° C. All values stated herein include all combinations and subcombinations of ranges and specific numerical values set forth therein.

  Typically, a base oil of the invention comprising a base of formula (I) is about 20% by weight of a compound of formula (I) or mixtures thereof, preferably more than about 50% by weight of a compound of formula (I) Or a mixture thereof. Such amounts can vary depending on the particular application and / or desired performance characteristics. The base oil of the present invention has an RBOT value of at least about 200.

  Synthetic base oils containing compounds of formula (I) may be used alone as a base for synthetic lubricant formulations. They also include other synthetic base oils such as polyalphaolefin (PAO), polyalkylene glycol (PAG), polybutene (PIB), alkylbenzene (AB), and conventional mineral oils (catalytic dewaxing process or conventional dewaxing process). 100-800 SUS SN oil etc.) can be used as a co-base oil. Base oils containing compounds of formula (I) are prepared from UCBO, BP hydrocracked oil, slack wax isomerized base oil or Fischer-Tropsch wax isomerized base from Chevron (collectively these fluids). They may be used in combination with hydrocracked base oils or hydroisomerized base oils such as Group II base oils and Group III bases). The above base typically has an RBOT value of about 150 or less.

  Generally, the base oil of the present invention, when used as a co-base oil, comprises from about 2 to about 60% by weight of the total lubricant base oil, preferably greater than about 5% of the total lubricant base oil. Using the base oil of the present invention greatly improves the thermal stability, oxidation stability and hydrolysis stability of the final lubricant, as well as lubricating additive solubility, sludge dispersibility and wear prevention or extreme pressure metal surface protection. .

  As mentioned above and as shown in the examples below, the compounds of formula (I) have excellent oxidative stability and viscosity metrics when compared to monoalkylated naphthalene. Thus, the synthetic base oils of the present invention may be essentially free of monoalkylated naphthalene and still provide excellent lubricating properties.

  The base oils of the present invention include antioxidants, detergent dispersants, viscosity index improvers, pour point depressants, oiliness improvers, antiwear agents, extreme pressure agents, friction modifiers, corrosion inhibitors, metal inertness. Additives conventionally used in lubricating oils, such as agents, rust inhibitors, seal compatibility improvers, antifoaming agents, emulsifiers, demulsifiers, bactericides or colorants, may be introduced.

  The base oil of the present invention may be used to lubricate the surfaces of various structures and elements that require lubrication. As used herein, “surface” refers to the outer portion of a structure or particle. The compounds of formula (I) are various functional fluid formulations such as crankcase lubricants, two-cycle engine oils, hydraulic lubricants, drilling lubricants, turbine oils, greases, gear oils, transmission oils and paper machine oils. It may be used in.

  The following examples are illustrative and not intended to be limiting.

The general procedure described herein was used to collect the following data. Details of Example 2 in Table 1 will be described. In this experiment 142 grams (1 mole) of 1-methylnaphthalene (1-MN) and 12.5 g USY catalyst premixed in a 500ml round bottom flask and the complete reaction system was purged with _{N 2} To eliminate air. The reaction flask was heated to 200 ° C. under a nitrogen atmosphere. 112 grams (0.5 mole) of 1-hexadecene was slowly added to the mixture over 2 hours. The reaction mixture was allowed to react for an additional 3 hours and then cooled to room temperature. Analysis of the reaction mixture by gas chromatograph was used to determine the amount of unreacted reactant, and this analysis indicated that most of the C ₁₆ olefin was converted to product. The product, ie, the lubricant product, is isolated by removing the solid catalyst by filtration and distilled at 120 ° C./vacuum less than 1 millitorr for more than 1 hour to remove any unreacted olefin and methylnaphthalene (MN). Removed.

  The resulting product was analyzed. The product characteristics are summarized below. Oxidation stability was analyzed based on a rotary cylinder oxidation test (RBOT) and a B-10 oxidation test. The RBOT test protocol is described in ASTM D2272.

  The B-10 oxidation test is used to evaluate mineral oils and synthetic lubricants with or without additives. The evaluation is based on the lubricant's resistance to air oxidation under defined conditions as measured by sludge formation, lead specimen corrosion, and neutralization number and viscosity changes. In this method, a sample is placed in a glass oxidation cell along with an iron, copper and aluminum catalyst and a weighed lead corrosion specimen. The cell and cell contents are placed in a bath maintained at a specified temperature and a measured volume of dry air is bubbled through the sample for the duration of the test. The cell is removed from the bath and the catalyst assembly is removed from the cell. The oil is inspected for the presence of sludge, total acid number (TAN) (ASTM 664) and kinematic viscosity (Kv) increase at 100 ° C. (ASTM D445). To determine the weight loss, the lead specimen is cleaned and weighed.

  Other properties to be measured include bromine number (ASTM D1159), viscosity index (VI) and pour point (ASTM D97).

  The following examples illustrate the excellent thermal and oxidative stability of compounds of formula (I) and the effect of several variables on the properties and yields of the same compounds, i.e. lubricant products. Yes.

  The data in Table 1 shows the molar ratio of MN / olefin on the lubricant product (for the purposes of the examples herein, methylnaphthalene acts as starting material and olefin acts as alkylating agent). The effect is demonstrated. Examples 1-3 show that the 1-MN / olefin molar ratio increase from 1/1 to 4/1 improves the oxidative stability of the lubricant product as measured by RBOT (RBOT time from 145 minutes). Increase to 805 minutes). A similar trend was observed for the 2-MN / olefin molar ratio (Examples 4 and 5). Changing the MN / olefin ratio did not seem to change the product viscosity, VI and pour point, and olefin conversion was very high (> 90%) for all MN / olefin ratios.

  The data in Table 2 demonstrates the effect of reaction temperature on the yield and properties of lubricants from 1-MN or 2-MN at a 2/1 MN / olefin molar ratio. Examples 6-8 increase the conversion of 1-hexadecene from 175 ° C. to 225 ° C. to 74% to 100%, but this does not affect viscosity, VI and pour point Is shown. Lubricant products at lower reaction temperatures such as 175 ° C. and 200 ° C. (Examples 6 and 7) have a longer RBOT than products produced at 225 ° C. (Example 8, 168 minutes). A similar trend was observed for the lubricant product from 2-MN (Examples 9-12). For example, by performing the reaction at lower reaction temperatures, such as 150 ° C. and 175 ° C. (Examples 9 and 10), a lubricant product having an RBOT time longer than 1000 minutes was obtained.

  The data in Table 3 demonstrates the effect of different olefins, different MN sources and different catalysts on lubricant yield and properties.

  Examples 13-15 show that 1-tetradecene, 1-hexadecene and 1-octadecene may be used as alkylating agents. By changing the olefin raw material, a lubricant product of 4.6-6.1 cS was obtained. All products had very long RBOT times (744-1000 minutes).

  Examples 16-18 illustrate that different methylnaphthalene sources or a mixture of naphthalene and methylnaphthalene can be used to produce a high quality lubricant product. “Suresol” -187 used in Examples 16 and 17 is commercially available from Koch Chemical Co. and contains 52% 2-MN and 45% 1-MN. In Example 18, a raw material containing equal amounts of naphthalene (1-MN and 2-MN) was used. Again, the products of Examples 16-18 were produced in high yield and had long RBOT times.

  Examples 19 and 20 demonstrate that using an MCM-22 catalyst instead of a USY catalyst results in an excellent RBOT time lubricant product.

  Table 4 shows 1-MN or 2 for commercial monoalkylated naphthalene lubricants (produced by the method disclosed in US Pat. -Comparison of lubricant products manufactured from MN. The data shows that the MN based lubricant product is superior in oxidation stability measured in RBOT time.

  While the invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made in the specific embodiments without departing from the scope and spirit of the invention. Let's go.

Claims (14)

A method for improving the oxidation stability of a lubricant having a rotary cylinder type oxidation test (RBOT) value of 200 minutes or less, comprising the following formula (I):

Wherein R ¹ and R ² are H, methyl group, ethyl group, propyl group or butyl group, R ³ and R ⁴ are alkyl groups having 6 to 24 carbon atoms, and x is 0 to 0 2 and y is 0 to 4, provided that at least one of R ¹ and R ² is not H and at least one of x and y is not 0)
A method for improving the oxidative stability of a lubricant, comprising the step of adding a base oil having a RBOT value of more than 200 minutes to the lubricant.   The method of improving the oxidative stability of a lubricant according to claim 1, wherein the base oil comprises at least 20% by weight of a compound of formula (I) or a mixture thereof.   The method for improving the oxidative stability of a lubricant according to claim 1, wherein the base oil comprises at least 50% by weight of a compound of formula (I) or a mixture thereof.   The method for improving the oxidative stability of a lubricant according to any one of claims 1 to 3, wherein the lubricant comprises at least 2 wt% of the base oil. The method for improving the oxidative stability of a lubricant according to any one of claims 1 to 4, wherein R ¹ is H and R ² is a methyl group. The method for improving the oxidative stability of a lubricant according to any one of claims 1 to 4, wherein R ² is H and R ¹ is a methyl group. The method for improving the oxidative stability of a lubricant according to any one of claims 1 to 4, wherein the sum of x and y is 1, R ¹ is H, and R ² is a methyl group. . The method for improving the oxidative stability of a lubricant according to claim 1, wherein the sum of x and y is 1, R ¹ is a methyl group, and R ² is H. .   The method for improving the oxidative stability of a lubricant according to any one of claims 1 to 4, wherein the sum of x and y is 1.   The method for improving the oxidative stability of a lubricant according to any one of claims 1 to 4, wherein the sum of x and y is greater than one.   The method for improving the oxidation stability of a lubricant according to any one of claims 1 to 10, wherein the base oil has an RBOT value of 500 to 1500 minutes. A synthetic base oil comprising a mixture of monoalkylated naphthalene and polyalkylated naphthalene, the improvement being at least 20% by weight of the following formula (I):

Wherein R ¹ and R ² are H, a methyl group, an ethyl group, an n-propyl group, an n-butyl group or a t-butyl group, and R ³ and R ⁴ have 6 to 24 carbon atoms. An alkyl group, x is 0 to 2, and y is 0 to 4, provided that at least one of R ¹ and R ² is not H and at least one of x and y is not 0.
A synthetic base oil comprising an alkylated naphthalene selected from the group consisting of: The synthetic base oil according to claim 12, wherein at least one of R ¹ and R ² is hydrogen. The synthetic base oil according to claim 13, wherein at least one of R ¹ and R ² is a methyl group.