阅读说明：本技术 通过离子催化剂低聚和加氢异构化由nao产生的基础油 (Oligomerization and hydroisomerization of base oils produced from NAO over ionic catalysts ) 是由 H·S·拉奇恩 H-K·C·蒂姆肯 于 2020-04-30 设计创作，主要内容包括：本文描述一种离子络合物催化剂,以及一种用于利用所述离子络合物催化剂进行C-(14)-C-(24)正α烯烃的烯烃低聚的方法。(Described herein is an ionic complex catalyst, and a method for C using the ionic complex catalyst 14 ‑C 24 A process for the olefin oligomerization of normal alpha olefins.)

1. A process for producing a base oil comprising:

(a) comprising C at a temperature equal to or greater than 130 ℃ in the presence of an ionic catalyst₁₄-C₂₄Reacting the normal alpha olefin of the NAO to produce an oligomer;

(b) at H₂Hydroisomerizing the oligomer product produced in (a) under an atmosphere using a catalyst comprising a noble metal and a medium pore zeolite;

(c) distilling and fractionating the hydroisomerized product of (b) to produce a light fraction up to 371 ℃, a low viscosity base oil in a 371 ℃, -488 ℃ distillate and a high viscosity base oil above 488 ℃, wherein the low viscosity base oil distillate has a viscosity at 100 ℃, a viscosity index of >130, < 15% Noack volatility, a pour and cloud point of < -20 ℃, and a cold-start simulator viscosity at-35 ℃ of <2500cP, wherein the high viscosity base oil distillate has a viscosity at 100 ℃, a viscosity index of >130 and a pour point of < 10 ℃ of 4.7cSt or higher,

(d) optionally recycling said light ends comprising n-alpha olefins and organic chlorides unconverted in step (a) to said conversion reaction step of (a).

2. The process of claim 1, (a) wherein the normal alpha olefin has a carbon number of from 14 to 24 and the temperature is from 130 ℃ to 200 ℃.

3. The method of claim 2, wherein said C₁₄To C₂₄The n-alpha olefins are derived from a bio-based source selected from the group consisting of: natural triglycerides, fatty acids and fatty alcohols, waxes.

4. The method of any one of claims 1 to 3, wherein the ionic catalyst is selected from the group consisting of: an ionic liquid catalyst with an HCl promoter; ionic complex catalysts which are homogeneous molten liquids at ambient temperature in the absence of HCl promoter.

5. The method of claim 4, wherein the ionic liquid catalyst comprises an anhydrous metal halide and an ammonium salt.

6. The method of claim 5, wherein the anhydrous metal halide is selected from the group consisting of: AlCl₃、AlBr₃、GaCl₃And GaBr₃。

7. The process of claim 4, wherein the ionic complex catalyst consists of an anhydrous metal halide acting as a Lewis acid and a donor molecule acting as a Lewis base.

8. The process of claim 7 wherein the ambient temperature homogeneous molten liquid consists of the anhydrous lewis acid metal halide and lewis base in a 3:2 molar ratio.

9. The method of claim 8, wherein the anhydrous lewis acid halide is selected from the group consisting of: AlCl₃、GaCl₃、InCl₃、AlBr₃、AlI₃、GaBr₃、GaI₃、InBr₃And InI₃And said lewis base is selected from the group consisting of: lutidine, collidine, alkylpyridine,Trioctylphosphine, alkylphosphine, urea, thiourea, acetamide, dialkylacetamide, alkylamide, octanonitrile, alkylnitrile.

10. The process of claim 1 wherein the reaction of (a) is carried out in a batch process with a catalyst amount of 0.25 to 5 volume percent.

11. The process of claim 1, wherein the reaction of (a) is carried out in a continuous process, with a catalyst amount of 0.1 to 5 volume percent and a residence time of 2 to 120 minutes.

12. The process of claim 2 wherein the normal alpha olefin is from C₁₄To C₁₈。

13. The method of claim 11, wherein the normal alpha olefin is hexadecene and the hexadecene to oligomer conversion is in the range of 40% to 90%.

14. The process of claim 1, wherein the low viscosity base oil distillate has a branching proximity of 17.9-22.2, a branching coefficient of 20.6-23.0, a free carbon index of 5.8-7.1, and a number of methyl branches per molecule of 1.6-2.4.

15. The method of claim 13, wherein the percent conversion is 82%.

16. The process of claim 1 wherein the hydroisomerization catalyst comprises a metal and a mesoporous zeolite.

17. The process of claim 1, wherein the hydroisomerization catalyst comprises a metal and amorphous silica-alumina.

18. The process of claim 1 wherein the reaction of (b) hydroisomerization is conducted in a batch process with a catalyst amount of 2 to 20 volume percent.

19. The process of claim 1 wherein said reaction of (b) hydroisomerization is carried out in a continuous process at a liquid hourly space velocity of from 0.2 to 5hr^-1。

20. The process of claim 1 wherein the reaction of (b) hydroisomerization is at 150 ℃ and 320 ℃ and 100 ℃ and 1,500psig of H₂The reaction is carried out under an atmosphere.

21. The process of claim 1, (b) wherein the base oil yield is greater than 90% of the starting NAO and no additional hydroisomerization refining step is required

22. The process of claim 1, (b) wherein the base oil yield is 90% to 99%, preferably above 95% of the starting NAO.

23. A base oil composition comprising a viscosity at 100 ℃ of 3.5 to 4.6cSt, >130 viscosity index, < 15% Noack volatility, <20 ℃ pour and cloud points, and a cold-start simulator viscosity at-35 ℃ of <2500cP, a branching proximity of 17.9 to 22.2, a branching coefficient of 20.6 to 23.0, a free carbon index of 5.8 to 7.1, a number of methyl branches per molecule of 1.6 to 2.4.

24. The base oil composition of claim 12 wherein the viscosity index is 130-142 and the pour point is-20 to-60 ℃.

25. The base oil composition of claim 12, wherein the mini rotational viscometer viscosity at-40 ℃ is less than 60,000 cP.

26. An ionic complex catalyst composition comprising an ambient temperature homogeneous molten liquid made from anhydrous lewis acid metal halide and lewis base in a 3:2 molar ratio.

27. The catalyst composition of claim 13, wherein the anhydrous lewis acid halide is selected from the group consisting of: AlCl₃、GaCl₃、InCl₃、AlBr₃、AlI₃、GaBr₃、GaI₃、InBr₃And InI₃And said lewis base is selected from the group consisting of: lutidine, collidine, alkylpyridine, trioctylphosphine, alkylphosphine, urea, thiourea, acetamide, dialkylacetamide, alkylamide, octanonitrile, alkylnitrile.

28. A process for producing a base oil comprising:

(a) comprising C at a temperature equal to or greater than 130 ℃ in the presence of an ionic catalyst₁₄-C₂₄Reacting the normal alpha olefin of the NAO to produce an oligomer;

(b) separating the reaction product produced in (a) into a light fraction comprising unconverted n-alpha olefins and organic chlorides and a further fraction comprising the oligomer product; recycling said light fraction comprising unconverted normal alpha olefins and organic chlorides to said conversion reaction step of (a);

(c) at H₂Hydroisomerizing the oligomer product produced in (b) under an atmosphere using a catalyst comprising a noble metal and a medium pore zeolite or silica-alumina;

(d) distilling and fractionating the hydroisomerized product of (c) to produce a light fraction up to 371 ℃, a low viscosity base oil in a 371-.

Background

To increase the fuel economy of automobiles, automobile manufacturers are developing higher efficiency internal combustion engines that operate using very low viscosity engine oils (OW-xx engine oils, including OW-8 and OW-12, which exceed the viscosity grades already on the market). The demand for such low-viscosity engine oils is expected to increase rapidly in the future.

In order to manufacture such specialty low viscosity lubricants for high efficiency engines, in addition to general group III base oils, lubricant manufacturers also require very high quality low viscosity base oils, such as base oils produced by Gas-to-Liquid (Gas-to-Liquid) processes or PAO type products. There are only a few commercial gas oil plants and most of these plants are not designed to produce base oils, so the supply of premium base oils produced by gas oil plants is very limited.

Low viscosity Polyalphaolefins (PAO) are high quality synthetic base oils and are commercially used from BF₃And a catalyst system consisting of C₁₀Or C₁₂N-alpha olefin (NAO) production. Due to excellent low temperature flow properties and low volatility, low viscosity PAOs are highly desirable blend stocks for superior lubricants for higher efficiency engines. However, such PAOs are very expensive and have a limited supply. Thus, there remains a need for base oil compositions for automotive and other applications having properties within a commercially acceptable range of physical properties, including one or more of viscosity, Noack volatility, and low temperature cold start viscosity. Further, there remains a need for base oil compositions and methods of manufacture having improved properties.

Many catalytic processes are currently used for the oligomerization of alpha olefins to produce lubricant base stocks.

Lewis acids (such as BF) are also known₃、AlCl₃And EtAlCl₂) Can be used as a catalyst in combination with an alkyl halide (e.g., t-butyl chloride), alcohol or Brdnsted acid for cationic polymerization of alpha olefins.

U.S. patent No. 7,527,944, incorporated herein by reference, discloses the use of ionic liquids as catalysts for the cationic polymerization of alpha olefins. Ionic liquids are a class of compounds that have been developed over the past decades. The term "ionic liquid" as used herein refers to a liquid that is obtainable by melting a salt and consists entirely of ions. The term "ionic liquid" includes both compounds having a high melting point and compounds having a low melting point (e.g., at or below room temperature). Ionic liquids having melting points below about 30 ℃ are commonly referred to as "room temperature ionic liquids" and are generally derived from organic salts having nitrogen-containing heterocyclic cations, such as imidazolium-and pyridinium-based cations.

U.S. patent No. 7,572,944 discloses ionic liquid catalysts comprising a pyridinium or imidazolium cation and a chloroaluminate anion. The use of ionic liquids as polymerization catalysts is known to provide certain advantages over conventional catalysts. In particular, ionic liquids are generally immiscible with hydrocarbons and can therefore be separated from the polyalphaolefin product by phase separation and recycled. In contrast, conventional lewis acid catalysts are typically quenched during the separation of the product.

With the growing demand for strong expectations for high performance engines, there is a strong need for alternative methods of incorporating ionic catalysts to produce low viscosity base oils with desirable characteristics.

Disclosure of Invention

One embodiment of the present invention is an ionic complex catalyst and method for performing C with an ionic complex catalyst in the absence of HCl cocatalyst₁₄-C₂₄A process for the olefin oligomerization of normal alpha olefins.

Further embodiments are ionic liquid compositions/catalysts with 2:1 anhydrous gallium chloride to 1 mole of ammonium chloride and for C₁₄-C₂₄A process for the olefin oligomerization of normal alpha olefins.

Further embodiments are ionic liquid compositions/catalysts with 1.8:1 anhydrous metal chloride to 1 mole ammonium chloride and for C₁₄-C₂₄A process for the olefin oligomerization of normal alpha olefins.

Another embodiment is a process for producing a base oil comprising:

a. reacting a high carbon number normal alpha olefin at a temperature of 130 ℃ or higher in the presence of an ionic catalyst to produce an oligomer;

b. at H₂Hydroisomerizing the oligomer product produced in (a) under an atmosphere using a catalyst comprising a metal and a medium pore zeolite;

c. distilling and fractionating the hydroisomerized product of (b) to produce a light fraction up to 371 ℃, a low viscosity base oil in the 371-.

d. Optionally recycling the light fraction comprising unconverted n-alpha-olefins and organic chlorides to the reactor to pass the conversion step a.

Drawings

FIG. 1 is a graph consisting of C₁₄-C₂₄Block diagram of NAO for making high quality base oil.

FIG. 2 is a GC plot of the oligomeric product showing C₁₆Chloride, unreacted olefin, dimer, trimer, tetramer, and higher oligomer product distributions.

FIG. 3 is a graph of simulated distillation of the oligomeric product.

FIG. 4 is a graph of low viscosity selectivity versus C for various ionic catalysts₁₆Graph of NAO olefin monomer conversion.

Fig. 5 is a multiple plot of branching proximity versus free carbon index, number of methyl branches, or branching coefficient for a premium low viscosity base oil composition produced from C16NAO, showing molecular structure modification during oligomerization and hydrofinishing (hydrorefining) steps.

FIG. 6 is a multi-plot of branching proximity versus pour point or viscosity index showing the effect of molecular structure modification on low viscosity base oil properties.

Detailed Description

Described herein is a process for making high quality base oils using n-alpha olefins having C₁₄-C₂₄Carbon number range (e.g., C)₁₄-C₂₄NAO), preferably C)₁₄-C₁₈The normal alpha olefins may be produced from petroleum crude oil sources by ethylene oligomerization, or from bio-based sources such as natural triglycerides, fatty acids and fatty alcohols, or by wax cracking. These C₁₄-C₂₄NAO will be compared with C₁₀And C₁₂NAOs are more readily available at lower cost. Further, described herein is a method of using an ionic complex catalyst that does not require HCl, the method provided byThe advantages over the prior art are: (1) higher conversion of NAO can be achieved using an ionic complex catalyst, (2) higher selectivity of low viscosity base oil fractions can be achieved using an ionic complex catalyst as described herein, (3) undesirable C is made using a process of using an ionic complex catalyst as described herein₁₆Less chloride by-product and (4) lower synthesis cost of the ion complex catalyst.

Definition of base oil Properties

As used herein, "base oil" refers to oil used in the manufacture of products including dielectric fluids, hydraulic fluids, compressor fluids, engine oils, greases, and metal working fluids.

Viscosity is a physical property that measures the flowability of the base stock. Viscosity is a strong function of temperature. Two commonly used viscosity measurements are dynamic viscosity and kinematic viscosity. Dynamic viscosity measures the internal flow resistance of a fluid. Examples of dynamic viscosity measurements for engine oils include cold-start simulator (CCS) viscosity and Micro Rotary Viscometer (MRV) viscosity. The CCS was used to simulate the viscosity of oil in the crankshaft bearings during cold start. Micro Rotary Viscosity (MRV) measures the yield stress and apparent viscosity of an engine oil after cooling to a final test temperature between-10 ℃ and-40 ℃ over a 45 hour period under controlled rate and shear stress. It is a key parameter in assessing pumpability of engine oils in cold weather. The SI unit of dynamic viscosity is pas. The conventional unit used is centipoise (cP), which is equal to 0.001Pa s (or 1m Pa s). The industry is slowly moving to SI units. Kinematic viscosity is the ratio of dynamic viscosity to density. The SI unit of kinematic viscosity is mm²And s. Other units commonly used in the industry are centistokes (cSt) at 40 ℃ (KV40) and centistokes at 100 ℃ (KV100) and Saybolt Universal Seconds (SUS) at 100 ° f and 210 ° f. Conveniently, 1mm²The/s is equal to 1 cSt. ASTM D5293 and D445 are the corresponding methods for measuring CCS and kinematic viscosity.

The Viscosity Index (VI) is an experimental number used to measure the kinematic viscosity of the base stock as a function of temperature. The higher the VI, the less the relative change in viscosity with temperature. Most lubricant applications require high VI basestocks, especially in multigrade automotive engine oils and other automotive lubricants that experience large operating temperature variations. ASTM D2270 is a generally accepted method for determining VI.

Pour point is the lowest temperature at which sample motion is observed. It is one of the most important properties of the base stock, as most lubricants are designed to work in the liquid phase. Low pour points are often required, especially in cold weather lubrication. ASTM D97 is a standard manual method of measuring pour point. It is increasingly being replaced by automated methods such as ASTM D5950 and ASTM D6749. For the examples in this patent, pour point was measured using ASTM D5950 with a 1 ℃ test interval.

Volatility is a measure of the loss of oil by evaporation at high temperatures. Volatility has become a very important technical parameter due to emissions and operating life issues, especially for lighter grades of base stocks. Volatility depends on the molecular composition of the oil, especially at the front of the boiling point curve. Noack (ASTM D5800) is a commonly accepted method for measuring the volatility of automotive lubricants. The Noack test method itself simulates evaporative losses in high temperature use, such as an operating internal combustion engine.

Branching coefficient (B1): the percentage of methyl hydrogens in the isoparaffins that appear in the chemical shift range of 0.5 to 1.05ppm, among all hydrogens that appear in the chemical range of 0.5 to 2.1ppm of 1H NMR.

Branching Proximity (BP): repeated methylene carbons (. epsilon. -CH) of four or more carbon atoms removed from the terminal or branched chain, occurring at 13C NMR chemical shift 29.8ppm₂Carbon).

Number of methyl branches per molecule: is a compound comprising 2-methyl, 3-methyl, 4-methyl, 5+ methyl, o-methyl and is present in¹³The number of unknown methyl groups between 0.5ppm and 22.0ppm of C NMR chemical shifts, except for the terminal methyl carbon appearing at 13.8 ppm.

Free carbon index: is a methylene carbon (. epsilon. -CH) of four or more carbon atoms removed from the terminal group or branch per molecule₂Carbon) average number.

¹³C NMR chemical shift distribution:

branched chain	NMR chemical shifts (ppm)
		2-methyl radical	22.5
3-methyl group	19.1 or 11.4
		4-methyl group	14.0
5+ methyl group	19.6
		Internal ethyl radical	10.8
N-propyl radical	14.4
		Ortho-methyl group	16.7

Reference: an assessment of the varied branch carbon reactions to specific branch locations and lengths using branched and calculated values (Lindeman, L.P., Journal of Qualitative Analytical Chemistry 43,19711245 ff; Netzel, D.A. et al, Fuel,60,1981,307 ff.).

Ionic catalysts, as described herein, include ionic liquid catalysts, ionic complex catalysts, and ionic liquid catalysts with HCl co-catalyst. The ionic liquid catalyst is prepared from anhydrous metal halide and quaternary ammonium salt. AlCl₃、AlBr₃、GaCl₃Or GaBr₃Is preferably a metal halide. Alkylammonium halides, alkylimidazolium halides and alkylpyridinium halides are preferred ammonium salts. Ionic complex catalysts are made from anhydrous metal halides (lewis acids) and molecules with strong electron donor atoms that will act as lewis bases for use with anhydrous metal halides. AlCl₃、AlBr₃、GaCl₃Or GaBr₃Is preferably a metal halide. Urea, thiourea, alkylamides and alkylphosphines are preferred molecules.

Provided herein (I-III) are embodiments of methods of making the disclosed low viscosity base oil compositions.

I.

a. In the presence of an ionic catalyst, at a temperature of 130 ℃ or more₁₄To C₂₄Reacting normal alpha olefin monomers to produce oligomers;

b. at H₂Hydroisomerizing the oligomer product produced in (a) under an atmosphere using a catalyst comprising a metal and a medium pore zeolite or silica-alumina;

c. distilling and fractionating the hydroisomerized product of (b) to produce a low viscosity base oil in the light ends (up to 700 ℃ F. or 371 ℃ C.), 700-.

d. Optionally recycling the light fraction comprising n-alpha olefins and organic chlorides unconverted in step a to the reactor to pass through the conversion step a.

An embodiment of the above process is oligomer selectivity, wherein the oligomer product is predominantly dimer, with dimer selectivity equal to or greater than 40 wt% to 90%, preferably greater than 50% and most preferably greater than 60%.

II.

a. In the presence of an ionic catalyst, at a temperature of 130 ℃ or more₁₄To C₂₄Reacting normal alpha olefin monomers to produce oligomers;

b. at H₂Hydroisomerizing the oligomer product produced in (a) under an atmosphere using a catalyst comprising a metal and a medium pore zeolite;

c. distilling and fractionating the hydroisomerized product of (b) to produce a light fraction (up to 700 ℃ F. or 371 ℃ C.), a low viscosity base oil in the 700 ℃ 910 ℃ F. (371 ℃ 488 ℃) distillate and a high viscosity base oil above 910 ℃ F. (488 ℃), wherein the low viscosity base oil exhibits a viscosity at 100 ℃ of 3.5-4.6cSt with properties of a VI of >130, < 15% Noack volatility, <20 ℃ pour and cloud points and a cold start simulator viscosity at-35 ℃ of <2500 cP.

d. Optionally recycling the light fraction comprising n-alpha olefins and organic chlorides unconverted in step a to the reactor to pass through the conversion step a.

III.

a. In the presence of an ionic catalyst, at a temperature of 130 ℃ or more₁₄To C₂₄Reacting normal alpha olefin monomers to produce oligomers;

b. at H₂Hydroisomerizing the oligomer product produced in (a) under an atmosphere using a catalyst comprising a metal and a medium pore zeolite;

c. distilling and fractionating the hydroisomerized product of (b) to produce a light fraction (up to 700 ℃ F. or 371 ℃), a low viscosity base oil in the 700 ℃ 910 ℃ F. (371 ℃ 488 ℃) distillate and a high viscosity base oil above 910 ℃ F. (488 ℃), wherein the low viscosity base oil exhibits a viscosity at 100 ℃ of from 3.5 to 4.6cSt, a branching proximity of from 17.9 to 22.2, a branching coefficient of from 20.6 to 23.0, a free carbon index of from 5.8 to 7.1, and a number of methyl branches per molecule of from 1.6 to 2.4

d. Optionally recycling the light fraction comprising n-alpha olefins and organic chlorides unconverted in step a to the reactor to pass through the conversion step a.

Feedstock material

The carbon number of the raw material is in the range of 14 to 24 (C)₁₄-C₂₄) Preferably C₁₄-C₁₈By petroleum processing, or by biologically derived alpha olefins, or byWax cracking occurs. The feed material may comprise up to 40 wt% of the total carbon content in C₆-C₁₂Lower carbon number normal alpha olefins in the range and may comprise up to 10 wt% of at most C₆-C₂₀Paraffins in the carbon number range.

Olefin oligomerization

In the use for C₁₄-C₂₄In a particular embodiment of the oligomerisation process, the chemical reaction is controlled to maximise dimer yield and to minimise higher molecular weight oligomers (trimers, tetramers and higher oligomers). Fig. 1 shows a simplified block diagram of the method of the present invention. The oligomerization can be carried out in a suitable reactor in semi-batch mode or continuous mode. A particular embodiment is a hexadecene to oligomer conversion, wherein the percent conversion is in the range of 40% to 85%.

In one embodiment, the reaction mixture is distilled to remove unreacted monomers. For example, unreacted monomer may be separated from the oligomer product (such as by distillation) and may be recycled back to the mixture of first and/or second feed stocks for oligomerization thereof.

Ionic catalysts

Generation is known in the artIonic liquid catalystThe method of (1). U.S. patent No. 7,527,944, incorporated herein by reference, discloses the use of ionic liquids as catalysts for the cationic polymerization of alpha olefins. Ionic liquids are a class of compounds that have been developed over the past decades. The term "ionic liquid" as used herein refers to a liquid that is obtainable by melting a salt and consists entirely of ions. The term "ionic liquid" includes both compounds having a high melting point and compounds having a low melting point (e.g., at or below room temperature). Ionic liquids having melting points below about 30 ℃ are commonly referred to as "room temperature ionic liquids" and are generally derived from organic salts having nitrogen-containing heterocyclic cations, such as imidazolium-and pyridinium-based cations.

C is set forth herein₁₄-C₂₄Process conditions that maximize NAO conversion and dimer yield. Can use C₁₆NAO asModel feed pair for C₁₄-C₂₄Various ionic liquid catalysts of dimerization were tested.

Preferably the ionic liquid composition is 2 moles of anhydrous metal chloride to 1 mole of ammonium chloride. The mixing of these two ionic materials forms an ionic liquid made entirely of cations and anions.

2MCl₃+ ammonium chloride → [ ammonium cation]⁺[M₂Cl₇]^-

Wherein M is a metal selected from the group consisting of aluminum, gallium, and indium. To improve the selectivity of ionic liquid catalysts for low viscosity base oils, the presence of anhydrous HCl promoter is required, as reported in US 10,435,491, incorporated herein by reference.

The composition of the ionic liquid catalyst may be slightly modified to 1.8:1 anhydrous metal chloride to 1 mole of ammonium chloride to reduce the lewis acidity of the catalyst.

A preferred embodiment is the use of an anhydrous gallium chloride-containing ionic liquid catalyst that exhibits a higher selectivity for low viscosity base oils than aluminum chloride-containing catalysts.

Another embodiment of the invention is a class of compounds useful for C₁₄-C₂₄Olefin oligomerization of NAOIonic complex catalystWhich exhibit higher olefin oligomerization performance compared to conventional ionic liquid catalysts, in particular, ionic complex catalysts provide approximately 10 wt.% or higher dimer selectivity at constant NAO conversion compared to ionic liquid catalysts.

Such ionic complex catalysts are homogeneous molten liquids at ambient temperature, made from anhydrous lewis acid metal halides and lewis bases in a 3:2 molar ratio. Anhydrous lewis acid halides (such as AlCl)₃、GaCl₃、InCl₃、AlBr₃、AlI₃、GaBr₃、GaI₃、InBr₃And InI₃) Can be used for preparing ion complex catalyst. Suitable solid lewis bases include molecules containing atoms with electron pairs, such as oxygen, phosphorus, sulfur, nitrogen. Examples of Lewis bases include lutidine, collidine, alkylPyridine, trioctylphosphine, alkylphosphine, ureas (e.g., N '-dimethylurea, N' -diethylurea), thioureas (e.g., thiourea, N-methylthiourea, N '-dimethylthiourea, N-ethylthiourea, N' -diethylthiourea), amides (e.g., acetamide, propionamide, benzamide), dialkylacetamides, alkylamides, octanenitrile, and alkylnitriles. When these two solid components (strong lewis acid and lewis base) are mixed in powder form in a molar ratio of 3:2, their strong interaction results in deep eutectic behavior of the mixed solid powder, and then the mixture becomes liquid at ambient temperature.

Without being bound by any theory, it is believed that the addition of a strong lewis donor ligand to the group 13 metal halide results in the disproportionation of the metal species into an ionic complex of cations and anions that are in equilibrium with a neutral complex, such as described in the following equation:

3AlCl₃+2L←→[AlCl₃L]+[Al₂Cl₆L]←→[M₂Cl₇]^-+[MCl₂L₂]⁺

wherein M is a metal selected from the group consisting of aluminum, gallium, and indium; x is a halide selected from the group consisting of chloride, bromide, and iodide; and L represents a lewis basic donor ligand. The eutectic behavior (becoming liquid) may result from the formation of ionic species.

Hydroisomerization

As a refining step, the oligomer product is hydrogenated using a hydrogenation catalyst at high pressure in the presence of hydrogen to produce a fully saturated base oil. PAO hydrogenation is typically carried out using a heterogeneous hydrogenation catalyst comprising nickel. Hydrogenation of oligomers can also be carried out using noble metal (such as Pt, Pd or Ru) supported catalysts.

Hydroisomerization catalysts useful in the present invention typically comprise a shape selective molecular sieve, a metal or mixture of metals that is catalytically active for hydrogenation, and a refractory oxide support. The presence of the hydrogenation component leads to improved product stability. Typical catalytically active hydrogenation metals include chromium, molybdenum, nickel, vanadium, cobalt, tungsten, zinc, platinum and palladium. Platinum and palladium are particularly preferred, with platinum being most preferred. If platinum and/or palladium are used, the metal content is generally in the range of from 0.1 to 5 weight percent, typically from 0.1 to 2 weight percent and not more than 10 weight percent of the total catalyst. Hydroisomerization catalysts are discussed, for example, in U.S. patent nos. 7,390,763 and 9,616,419 and U.S. patent application publications 2011/0192766 and 2017/0183583.

Platinum and palladium and ruthenium may be preferred metals for the hydroisomerization. Other group VIII transition metals such as Ni, Co, Fe, W, Re, Os or Ir may be used in the process. Zeolites comprising one-or two-dimensional 10-membered ring pore structures, such as those having MFI, MEL, MFS, MRE, MTT, SFF, STI, TON, OSI or NES framework types, may be used. Suitable zeolites include ZSM-5, ZSM-11, ZSM-23, ZSM-35, ZSM-48, ZSM-57, SSZ-32, SSZ-35, SSZ-91, SSZ-95, SSZ-109, NU-87, ALPO-31, SAPO-11. Amorphous materials having acid sites bound to metals can be used for hydroisomerization. Suitable amorphous materials include amorphous silica-alumina, silica-alumina-titania, zirconia-alumina, and zirconia-ceria-alumina.

The conditions of the hydroisomerization are adjusted to obtain an isomerized hydrocarbon mixture having the specific branching properties as described above, and thus the conditions of the hydroisomerization will depend on the characteristics of the feed used. The reaction temperature is generally between about 200 ℃ and 400 ℃, preferably between 260 ℃ and 370 ℃, most preferably between 288 ℃ and 345 ℃, and the Liquid Hourly Space Velocity (LHSV) is generally about 0.2hr^-1And about 5hr^-1Preferably at about 0.5hr^-1And about 3hr^-1In the meantime. The pressure is generally from about 15psig to about 2500psig, preferably from about 50psig to about 2000psig, more preferably from about 100psig to about 1500psig, and most preferably from 100psig to 800 psig. The low pressure provides increased isomerization selectivity, which results in more isomerization and less cracking of the feed, thus resulting in increased yields of the base stock boiling range hydrocarbon mixture. Hydrogen is present in the reaction zone during the hydroisomerization process, typically in a ratio of hydrogen to feedstock of from about 0.1 to 10MSCF/bbl (thousand standard cubic feet per barrel), preferably from about 0.3 to about 5 MSCF/bbl. Can react with hydrogenGas is separated from the product and recycled to the reaction zone.

The hydroisomerized product is distilled to produce three fractions: 700 ℉^-(371℃^-) A light fraction, a low viscosity base oil fraction (700-⁺Or 488 deg.C⁺). The low viscosity fraction in the 700-⁺(488℃⁺) The high viscosity fraction in the boiling range contains trimers, tetramers and higher oligomers.

Product properties of premium base oils

The low viscosity fraction contains mainly dimers and a small amount of trimers. The high viscosity fraction comprises mainly trimers and tetramers. A general GC plot and simulated distillation plot of the desired oligomer product distribution are shown in fig. 2 and 3.

To meet performance requirements and meet environmental requirements, desirable base oil properties are low viscosity, high Viscosity Index (VI), low pour and cloud points, low Noack volatility, and low temperature cold start simulator (CCS) viscosity.

The properties of the premium base oils described herein are as follows (table 1):

TABLE 1

Target Properties of premium base oils synthesized from NAO

From higher carbon number n-alpha olefins (C)₁₄-C₂₄) The resulting oligomer product has a very high Viscosity Index (VI) in excess of 150, which far exceeds the target VI of greater than 130. However, the dimer product has major disadvantages in terms of low temperature performance. The oligomer product is waxy and exhibits poor pour and cloud point low temperature properties.

The properties of the base oil are further improved by replacing the hydrofinishing step with a hydroisomerisation refining process using a metal containing medium pore zeolite catalyst.

At H₂The oligomerization product is hydroisomerized under an atmosphere using a catalyst comprising a noble metal and a medium pore zeolite to simultaneously saturate the double bonds in the olefin oligomer and isomerize the carbon backbone structure. The resulting product meets all of the target properties of a high quality, low viscosity base oil. No additional subsequent hydrogenation step is required.

The hydroisomerization process also produces several percent of off-gases and light products (gasoline and diesel boiling range hydrocarbons), resulting in some loss of base oil yield. Yield losses can be as high as 8-10 vol%. It is highly desirable to minimize yield loss. This is achieved by carrying out the oligomerization at an elevated temperature of 130 ℃ or higher to cause isomerization of the hydrocarbon backbone in the oligomer product, followed by mild hydroisomerization. By combining this optimized process, yields of over 95% of high quality base oil from the starting NAO are achieved.

The low viscosity base oil composition according to the invention will generally exhibit the following characteristics:

kinematic viscosity at 100 ℃ of 3.5-4.6cSt

Branching proximity of 17.9 to 22.2

A branching index of 20.6 to 23.0

Free carbon index of 5.8-7.1

Number of methyl branches per molecule of 1.6-2.4

Viscosity index of 130-142 pour point from-20 ℃ to-60 DEG C

Lubricant formulations containing base oils

The base oils disclosed herein may be used as lubricant base stocks to formulate finished lubricant products containing additives. In certain variations, the base stock prepared according to the methods described herein is blended with one or more additional base stocks, such as one or more commercially available PAOs, gas to oil (GTL) base stocks, one or more mineral base stocks, vegetable oil base stocks, algae-derived base stocks, a second base stock as described herein, or any other type of renewable base stock. Any effective amount of additional base stock may be added to obtain a blended base oil having the desired properties. For example, the blended base oil may include a ratio of a first base stock to a second base stock as described herein (e.g., a commercially available base oil PAO, a GTL base stock, one or more mineral base stocks, a vegetable oil base stock, an algae-derived base stock, a second base stock as described herein) of about 1-99%, about 1-80%, about 1-70%, about 1-60%, about 1-50%, about 1-40%, about 1-30%, about 1-20%, or about 1-10%, based on the total mass of the composition that may be prepared.

Also disclosed herein are lubricant compositions comprising the hydrocarbon mixtures described herein. In some variations, the lubricant composition comprises: a base oil comprising at least a portion of a hydrocarbon mixture produced by any of the processes described herein; and one or more additives selected from the group consisting of: antioxidants, viscosity modifiers, pour point depressants, foam inhibitors, detergents, dispersants, dyes, markers, rust inhibitors or other corrosion inhibitors, emulsifiers, demulsifiers, flame retardants, antiwear agents, friction modifiers, thermal stability modifiers, multifunctional additives (e.g., additives that act as both antioxidants and dispersants), or any combination thereof. The lubricant composition may include the hydrocarbon mixture described herein as well as any lubricant additive, combination of lubricant additives, or available additive package.

Any of the compositions described herein that are used as a base stock may be present in greater than about 1% based on the total weight of the finished lubricant composition. In certain embodiments, the amount of base stock in the formulation is greater than about 2, 5, 15, or 20 weight percent based on the total weight of the formulation. In some embodiments, the amount of base oil in the composition is about 1-99%, about 1-80%, about 1-70%, about 1-60%, about 1-50%, about 1-40%, about 1-30%, about 1-20%, or about 1-10%, based on the total weight of the composition. In certain embodiments, the amount of base stock in the formulations provided herein is about 1%, 5%, 7%, 10%, 13%, 15%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 99% based on the total weight of the formulation.

As is known in the art, the type and amount of lubricant additives are selected in conjunction with the base oil such that the finished lubricant composition meets certain industry standards or specifications for a particular application. In general, the concentration of each additive in the composition, when used, can range from about 0.001 wt% to about 20 wt%, about 0.01 wt% to about 10 wt%, about 0.1 wt% to 5 wt%, or about 0.1 wt% to about 2.5 wt%, based on the total weight of the composition. Further, the total amount of additives in the composition may range from about 0.001 wt% to about 50 wt%, about 0.01 wt% to about 40 wt%, about 0.01 wt% to about 30 wt%, about 0.01 wt% to about 20 wt%, about 0.1 wt% to about 10 wt%, or about 0.1 wt% to about 5 wt%, based on the total weight of the composition.

In some variations, the base oils described herein are formulated into lubricant compositions for use as two-stroke engine oils, transmission oils, hydraulic oils, compressor oils, turbine oils and greases, automotive engine oils, gear oils, marine lubricants, and process oils. Process oil applications include, but are not limited to: rolling mill oils, spooling oils, plasticizers, spindle oils, polymer treatments, mold release agents, coatings, adhesives, sealants, polishes and wax blends, stretching and stamping oils, rubber compounds, pharmaceutical process aids, personal care products, and inks.

In other variations, the base oils described herein are formulated as an industrial oil or grease formulation comprising at least one additive selected from the group consisting of antioxidants, anti-wear agents, extreme pressure agents, anti-foam agents, detergents/dispersants, rust and corrosion inhibitors, thickeners, tackifiers, and demulsifiers. It is also contemplated that the base stock of the present invention may be formulated as a dielectric heat transfer fluid comprised of a relatively pure blend of compounds selected from the group consisting of aromatic hydrocarbons, polyalphaolefins, polyesters, and natural vegetable oils, and additives for improving pour point, increasing stability, and reducing oxidation rate.

The invention will be further illustrated by the following examples which are not intended to be limiting.

Example 1:has the advantages ofIonic liquid catalyst of anhydrous aluminum chloride

Example 1-1: n-butylpyridinium chloroaluminate (C)₅H₅NC₄H₉Al₂Cl₇Abbreviated as [ BuPy][Al₂Cl₇]) N-butylpyridinium chloroaluminate was synthesized by: in a glove box at N₂Anhydrous AlCl with the molar ratio of 2:1 is added under the atmosphere₃The powder and the dry N-butylpyridinium chloride powder were slowly mixed together. The mixture was then changed to a liquid by heating slightly to-50 ℃ while stirring. A small portion of each solid was then added alternately to the beaker at a time to continue preparing the molten liquid until all ingredients were added and fully dissolved. The liquid was stirred overnight and then filtered through a fine frit to remove any remaining solids. The composition of this ionic liquid catalyst is shown in table 2.

Examples 1 to 2: 1-butyl-3-methylimidazolium chloroaluminate (abbreviated as [ BMIM ]][Al₂Cl₇])

This ionic liquid was synthesized using the procedure of example 1-1, except that 1-butyl-3-methylimidazolium chloride was used in the synthesis.

Examples 1 to 3: 1-Ethyl-3-methylimidazolium chloroaluminate (abbreviated [ EMIM ]][Al₂Cl₇])

This ionic liquid was synthesized using the procedure of example 1-1, except that 1-ethyl-3-methylimidazolium chloride was used in the synthesis.

Examples 1 to 4: n-butyl-3-methylpyridinium chloroaluminate (C)₄H₉N(C₄H₉)(CH₃)Al₂Cl₇Abbreviated as [ BMPy][Al₂Cl₇])

This ionic liquid was synthesized using the procedure of example 1-1, except that N-butyl-3-methylpyridinium chloride was used in the synthesis.

Examples 1 to 5: n-butylpyridinium chloroaluminate (abbreviated as [ BuPy)][1.8Al₂Cl₇])

This ionic liquid was synthesized using the procedure of example 1-1 and the same starting materials. However, it is not limited toAnhydrous AlCl₃And N-butylpyridinium chloride in a molar ratio of 1.8: 1. This slightly reduces the catalyst acidity and increases the dimer selectivity.

TABLE 2

Composition of ionic liquid catalyst

Example 2:ionic liquid catalyst with anhydrous gallium chloride: n-butylpyridinium chlorogallate (C)₅H₅NC₄H₉Ga₂Cl₇Abbreviated as [ BuPy][Ga₂Cl₇])

N-butylpyridinium chlorogallate was synthesized by: in a glove box at N₂Under the atmosphere, anhydrous GaCl with the molar ratio of 2:1 is added₃The powder and the dry N-butylpyridinium chloride powder were slowly mixed together. The mixture was then changed to a liquid by heating slightly to-50 ℃ while stirring. A small portion of each solid was then added alternately to the beaker at a time to continue preparing the molten liquid until all ingredients were added and fully dissolved. The liquid was stirred overnight and then filtered through a fine frit to remove any remaining solids.

Example 3:olefin oligomerization performance of various ionic liquid catalysts

This example shows the performance of various ionic liquid catalysts. The performance of the NAO oligomerization step of the catalyst was compared to the properties of the finished hydrogenated base oil fraction.

N-hexadecene n-alpha olefin (C) using ionic liquid catalyst from examples 1 and 2₁₆ ^＝NAO) oligomerization. Olefin oligomerization processes using ionic liquids are very efficient. Batch wise at 100 ℃ using only 0.5 vol% of ionic liquid catalyst. A small amount of HCl cocatalyst was added.

Each oligomer product was hydrogenated with a Pt, Pd/alumina catalyst. The final total liquid product is then distilled to produce three fractions: 700 ℉^-Is lightFractions, low viscosity base oil fraction (700-. A summary of the properties and final base oil properties are summarized in table 3.

TABLE 3

For n-C₁₆ ^＝Performance of various ionic liquid catalysts for NAO oligomerization and physical Properties of hydrogenated base oil products

The above results show that ionic liquid catalysts are very active in oligomerizing normal alpha olefins. The reaction uses only 0.5 vol% catalyst and achieves good conversion in the range of 25.5% to 59.1%. The resulting base oil product has a very high viscosity index ranging from 153 to 164. However, the low temperature properties of the base oil product are poor and the pour and cloud points are far from being targeted.

[EMIM][Al₂Cl₇]The best cold flow properties are obtained. In the presence of AlCl₃In the ionic liquid catalyst of (1), [ EMIM][Al₂Cl₇]Provides the highest alpha olefin conversion during the oligomerization step and produces a low viscosity base oil with better pour point (-16 ℃) and cloud point (-14 ℃) while having a viscosity index slightly below 153. This indicates [ EMIM][Al₂Cl₇]The catalyst causes some isomerization of the carbon backbone during oligomerization and results in a more highly branched and less waxy oligomer product. This isomerization/branching lowers the viscosity index and improves the cold properties, i.e. lowers the pour and cloud points.

Gallium-containing ionic liquid catalyst [ BuPy][Ga₂Cl₇]Has more selectivity to low-viscosity base oil. Containing AlCl₃Ionic liquid catalyst (example 3.3) and [ BuPy][Ga₂Cl₇](example 3.5) shows very similar olefin conversions of 47%. [ BuPy][Ga₂Cl₇]The catalyst showed a low viscosity oil selectivity of 63.6%, whereas [ EMIM][Al₂Cl₇]It was found to be 38.1%.

The low viscosity oil selectivity for each catalyst is plotted as a function of NAO conversion in FIG. 4. This figure compares the potential of each type of ionic catalyst for selective production of low viscosity oil. All of the aluminum chloride-containing ionic liquid catalysts achieved selectivity to the low viscosity oil fraction of only about 40 wt.%, while the gallium chloride-containing ionic liquid catalysts exhibited selectivity of about 60+ wt.%, an improvement of about 20+ wt.%.

Example 4-1:improvement of olefin oligomerization process using ionic liquid catalyst

This example shows an improvement in the oligomerization process for incorporating more isomerization during the oligomerization process. Surprisingly, new olefin oligomerization conditions were found which provide: (1) high conversion of olefins, (2) high selectivity of dimer products, and (3) greatly improved product properties of the finished base oil. The impact of the performance characteristics is summarized in table 4.

TABLE 4

Ionic liquid catalyzed n-C₁₆ ^＝Process improvement of NAO oligomerization and physical properties of hydrogenated base oil products

*: the product property values for example 4-1 in Table 3 are from the batch oligomerization run sample of example 3-1.

The [ BuPy ] from examples 1 to 5 was used][1.8Al₂Cl₇]N-hexadecene n-alpha olefin (C)₁₆ ^＝NAO) was subjected to oligomerization. The oligomerization was carried out in a continuous unit using 0.2 vol% of the ionic liquid catalyst. A small amount of HCl cocatalyst was added. The oligomerization temperature was carried out as low as 80 ℃ and then raised to 130 ℃ and 180 ℃.

The olefin conversion dropped from 53% to 41% as the temperature of the oligomerization increased from 80 ℃ to 130 ℃. In the use of C₁₀This decrease in conversion at higher temperatures was observed in earlier studies of NAO oligomerization (US 10,435,491). Based on this, C has been₁₀The upper temperature range for the NAO oligomerization was limited to 130 ℃.

When the oligomerization temperature is raised to 180 ℃, surprisingly the olefin conversion increases to values even higher than 80 ℃ olefin oligomerization (53% at 80 ℃, 41% at 130 ℃, then 56% at 180 ℃). At higher temperatures, dimer selectivity also increased significantly. The dimer selectivity was 57% at 180 ℃ and only 15% at 80 ℃.

The oligomer product (300g) was hydrogenated using 30g of Pt, Pd on alumina catalyst in batch mode at 250 deg.C at 800psig for 6 hours. The final total liquid product is then distilled to produce three fractions: 700 ℉^-(371℃^-) A light fraction, a low viscosity base oil fraction (700-⁺Or 488 deg.C⁺) And then base oil properties were measured.

The results in table 4 show that oligomerization at high temperatures of 180 ℃ significantly improves the low temperature properties of the finished base oil while reducing the viscosity index within the desired range. The results show that the oligomerization temperature at 130 ℃ is not high enough to improve the low temperature properties of the base oil. At 180 ℃ oligomerization, the finished product exhibited a pour point of-20 ℃ and a cloud point of-5 ℃. These improvements bring the finished base oil closer to meeting the target properties of the premium base oils shown in table 1, but do not fully meet the target.

Example 4-2:structural analysis of base oils produced by improved olefin oligomerization process using ionic liquid catalysts

The composition of the hydrogenated low viscosity base oil products from examples 4-2 and 4-3 were analyzed using nuclear magnetic resonance spectroscopy (NMR) to determine the degree of isomerization and branching (methyl migration) of the carbon backbone during the oligomerization process.

NMR spectra were obtained using a Bruker 500 spectrometer. Each sample was contacted with CDCl₃Mixing at a ratio of 1:1 (weight: weight). Analysis of¹H NMR and¹³c NMR spectroscopy to obtain structural parameters.

TABLE 5

Oligomerization process variables and low viscosity base oils (hydrogenated n-C)₁₆ ^＝NAO oligomer) average molecular structure

Branching proximity: Theta-CH among total carbons₂Carbon (C)

Branching coefficient: % methyl hydrogens in total aliphatic Hydrogen

Methyl branching per molecule: the number of internal methyl groups in the molecule excluding the primary carbon methyl groups at the ends of the molecule

Free carbon index: per molecule of epsilon-CH₂Total number of carbon

The results in table 5 show that oligomerization at 180 ℃ increases the branching coefficient, i.e. causes more methyl branching in the molecule. This lowers the viscosity index and lowers the pour and cloud points.

Example 5:synthesis of various ionic complex catalysts

Example 5-1:ionic complex catalyst-TOPO-AlCl₃Synthesis of

By using 200.3g of anhydrous AlCl₃And 386.7g of trioctylphosphine oxide ((C)₈H₁₇C)₃PO) to prepare an ionic complex made from anhydrous aluminum chloride and trioctylphosphine oxide in a 3:2 molar ratio. The trioctylphosphine as such was dried in a vacuum oven at 40 ℃ overnight. Anhydrous aluminum chloride was used as is. The synthesis was performed in a glove box. Aluminum chloride and trioctylphosphine oxide powders were mixed in a beaker in an amount of about 1/20 using a magnetic stirrer. The mixture was then changed to a liquid by heating slightly to-50 ℃ while stirring. Then, about 1/20 portions of each solid were alternately added to the beaker at a time to continue preparing the molten liquid until all ingredients were added andand dissolved sufficiently. The liquid was stirred overnight and then filtered through a fine frit to remove any remaining solids. The composition of this ionic complex catalyst is shown in table 6.

Example 5-2:ionic complex catalyst-urea-AlCl₃Synthesis of

By using 480.6g of anhydrous AlCl₃And 144.1g Urea (H)₂NCONH₂) To prepare an ionic complex made of anhydrous aluminum chloride and urea in a 3:2 molar ratio. The urea as such was dried in a vacuum oven at 80 ℃ overnight. Anhydrous aluminum chloride was used as is. The synthesis was performed in a glove box. An amount of about 1/20 of aluminum chloride and urea powder was mixed in a beaker with a magnetic stirrer. The mixture was then changed to a liquid by heating slightly to-50 ℃ while stirring. Approximately 1/20 portions of each solid were then added alternately to the beaker at a time to continue to prepare the molten liquid until all ingredients were added and sufficiently dissolved. The liquid was stirred overnight and then filtered through a fine frit to remove any remaining solids. The composition of this ionic complex catalyst is shown in table 6.

Examples 5 to 3:ionic coordination complex-acetamide-AlCl₃Synthesis of

By using 413.9g of anhydrous AlCl₃And 122.1g of acetamide (CH)₃CONH₂) To prepare an ionic complex made of anhydrous aluminum chloride and acetamide in a 3:2 molar ratio. The acetamide as such was dried in a vacuum oven at 70 ℃ overnight. Anhydrous aluminum chloride was used as is. The synthesis was performed in a glove box. Aluminum chloride and acetamide powders in amounts of about 1/20 were mixed in a beaker with a magnetic stirrer. The mixture was then changed to a liquid by heating slightly to-50 ℃ while stirring. Approximately 1/20 portions of each solid were then added alternately to the beaker at a time to continue to prepare the molten liquid until all ingredients were added and sufficiently dissolved. The liquid was stirred overnight and then filtered through a fine frit to remove any remaining solids. The composition of this ionic complex catalyst is shown in table 6.

Example 5-4：Ion coordination complex-TOP-AlCl₃Synthesis of

By using 160.2g of anhydrous AlCl₃And 296.5g of trioctylphosphine ((C)₈H₁₇C)₃P) to prepare an ionic complex made from anhydrous aluminum chloride and trioctylphosphine in a 3:2 molar ratio. The samples as received were used as received. The synthesis was performed in a glove box. An amount of about 1/20 aluminum chloride powder and trioctylphosphine liquid were mixed in a beaker with a magnetic stirrer. The mixture was then changed to a liquid by heating slightly to-50 ℃ while stirring. Portions 1/20 of each component were then added alternately to the beaker at a time to continue to prepare the molten liquid until all ingredients were added and fully dissolved. The liquid was stirred overnight and then filtered through a fine frit to remove any remaining solids. The composition of this ionic complex catalyst is shown in table 6.

TABLE 6

Composition of sample of ion-complexing complexes

Example 6: using AlCl₃C of an ionic coordination complex with a Lewis base₁₆ ^＝Olefin oligomerization of NAO

This example reports the performance of the ionic coordination complex catalyst described in example 5 and compares the results with those of the ionic liquid catalyst (example 1.1).

1-hexadecene was oligomerized in the presence of the ionic coordination complex catalyst of example 5. A three-necked 2L round bottom flask equipped with a magnetic stir bar, dropping funnel and reflux condenser was prepared. About 500cc of 1-hexadecene was charged into the flask and a very small dry nitrogen purge was applied while the liquid was heated to 150 ℃. Once 1-hexadecene in the round-bottom flask reached thermal equilibrium, 0.25 volume percent or 0.5 volume percent of the ionic coordination complex from example 5 was added dropwise at 10 minute intervals using a dropping funnel. After the addition, the oligomerization reaction was continued for 30 more minutes to produce a reaction mixture.

The hydrocarbon product was recovered and analyzed by GC simulated distillation to calculate C₁₆ ^＝Conversion of NAO and to C₁₆Selectivity of organic chloride, low viscosity base oil and high viscosity base oil. The results are summarized in table 7.

For using TOPO-AlCl₃The oligomer product of the catalyst was hydrogenated to produce a finished base oil fraction and the properties are reported in table 1.

TABLE 7

For n-C₁₆ ^＝Properties of various Ionic Complex catalysts for NAO oligomerization comparison of Ionic Complex catalysts with Ionic liquid catalysts

Surprisingly, it was found that ionic coordination complex catalysts are more active than ionic liquid catalysts. At a reaction temperature of 150 ℃, the ionic complex catalyst achieves a 1-hexadecene conversion of 56.9% to 81.2%, while [ BuPy%][AlCl₃]The ionic liquid catalyst required a reaction temperature of 180 ℃ to achieve 56.1% conversion (examples 6-1 to 6-3 vs. examples 3-4).

It has also been found that the ionic complex catalyst is more selective for low viscosity fractions than the ionic liquid catalyst. Example 6-1 vs. 3-4 have similar 1-hexadecene conversion. The ionic complex catalyst (example 6.1) showed a dimer selectivity of 68.2%, which is superior to the dimer selectivity of the ionic liquid catalyst (56.8% dimer selectivity in example 3.4).

acetamide-AlCl₃The catalyst achieved a very good conversion of 69.2% with a catalyst loading of only 0.25% by volume. This catalyst showed a very good dimer selectivity of 64 wt%.

Figure 4 also contains low viscosity oil selectivity data for the ionic complex catalyst as a function of NAO conversion. This figure compares the potential of each type of ionic catalyst to produce low viscosity oil. This figure shows that low viscosity oil selectivities of up to 80 wt.% can be achieved using these ionic complex catalysts. This is a significant improvement over the baseline ionic liquid catalyst containing aluminum chloride (about 40%) or the ionic liquid catalyst containing gallium chloride (about 10%).

Another surprise is that good selectivity is obtained without the need to add anhydrous HCl to the catalyst. C formed without addition of HCl in the presence of an ionic complex catalyst₁₆Less chloride. This will make the product purification easier.

Example 7Improvement of properties of the finished oil by a hydroisomerization refining step

This example shows the use of a hydroisomerization refining step to improve the product properties of a premium base oil.

N-hexadecene n-alpha olefin (C) using the ionic liquid catalyst from example 1-1₁₆NAO) oligomerization. Batch wise at 100 ℃ using only 0.5 vol% of ionic liquid catalyst. A small amount of HCl cocatalyst was added.

The oligomer product was divided into three portions. A batch of oligomer product was hydrogenated over a Pt, Pd/alumina catalyst. Two additional batches of oligomer product were hydroisomerized using noble metals and medium pore zeolites to simultaneously saturate the double bonds and isomerize the carbon backbone structure. The final total liquid product is then distilled to produce three fractions: 700 ℉^-(371℃^-) A light fraction, a low viscosity base oil fraction (700-⁺Or 488 deg.C⁺). The base oil fraction had the physical properties shown in table 8.

TABLE 8

Modification of base oil Properties by hydroisomerization refining step by C₁₆ ^＝Comparison of physical Properties of base oils made by NAO oligomerization and refining with the hydroisomerization refining step

Example 7-1 shows the use of an ionic liquidOlefin oligomerization over bulk catalyst followed by Pt, Pd/Al₂O₃The nature of the base oil produced by hydrogenation of the catalyst. The products (low and high viscosity base oil fractions) have excellent viscosity indices of 152 and 156, respectively.

However, the base oil is waxy and has poor cold flow properties because the low viscosity base oil fraction exhibits a pour point of-4 ℃ and a cloud point of 6 ℃, and the heavy oil fraction exhibits a pour point of-1 ℃ and a cloud point of 0 ℃. The low viscosity base oil fraction becomes too waxy at lower temperatures and exhibits very poor CCS viscosity at-30 ℃. This product is not sufficient as a high quality low viscosity base oil due to poor cold flow properties.

Example 7-2 is a base oil produced by exactly the same oligomerization process as example 7-1, except that the hydroisomerization completion step was performed. The base oil was refined with a platinum/medium pore zeolite/alumina catalyst. Both the low viscosity base oil and the high viscosity base oil fractions showed much improved pour and cloud points. The low viscosity distillate base oil has excellent Noack volatility, VI and good CCS down to-30 ℃.

Example 7-3 is a base oil produced by exactly the same oligomerization process as examples 7-1 and 7-2, except that a hydroisomerization refining step was performed using another Pt/medium pore zeolite/alumina catalyst. Both the low viscosity base oil and the high viscosity base oil fractions showed much improved pour and cloud points. The low viscosity distillate base oil has excellent Noack volatility, VI and good CCS down to-30 ℃.

In Table 8, the low viscosity base oil fractions of examples 7-2 and 7-3 were also compared with synthetic 4cSt PAO (comparative) obtained from a commercial source. The low viscosity base oil fraction of the present invention exhibits much improved pour and cloud points (although not exactly as good as the 4cSt PAO), while exhibiting better Noack volatility and higher VI than the commercial 4cSt PAO.

The results from examples 7-2 and 7-3 show that excellent low viscosity base oils can be synthesized from high carbon number NAO by oligomerization (dimerization) using an ionic liquid catalyst followed by hydroisomerization with a metal/zeolite catalyst. The results show that this low viscosity base oil of the present invention is different from the general PAO and is uniquely suitable for making a high quality lubricant with a new feed source.

Example 8Molecular Structure analysis of our high quality Low viscosity base oils

The hydrogenation or hydroisomerization products from example 7-2 were analyzed for composition using nuclear magnetic resonance spectroscopy (NMR) and reported in table 9 below (example 8-3). Two additional samples refined at lower temperature hydroisomerization were also analyzed, where the isomerization was not efficient enough to produce good low viscosity base oils with acceptable low temperature properties. These results were compared with 1-decene (l-C)₁₀ ^＝) Comparison was made with 4cSt PAO made with NAO.

TABLE 9

Relationship between average molecular Structure and Low viscosity base oil Properties from n-C Using Ionic liquid catalysts₁₆ ^＝Comparison of NAO-produced Low viscosity base oils with 4cSt PAO

Examples 8-1 and 8-2 were refined by performing hydroisomerization at low temperature, and the low viscosity base oil properties did not fully meet the targets in table 1. As the product properties improved (example 8-3), the oligomers were more isomerized as evidenced by a higher branching index (i.e., more methyl branches were produced). Isomerization also reduces branching proximity and reduces ε -CH₂Carbon. With C₁₆ ^＝The dimer is converted during hydroisomerization over a zeolite catalyst and the linear carbon segments in the molecule are isomerized by methyl migration.

Through C₁₆ ^＝Low viscosity base oils from NAO oligomerization and blends of C₁₀ ^＝The 4cSt PAOs produced by NAO are very different because the process of the invention uses much longer olefin molecules. And is represented by C₁₀ ^＝NAO produced 4cSt PAO (comparative) in contrast, the base oil pack of the present inventionContaining more epsilon CH₂I.e., higher branching proximity and free carbon index (examples 8-1 and 8-2), which contribute to the VI of the process being higher than the VI of the PAO. From C₁₀Commercial 4cSt PAOs made from NAO contain mainly trimers and tetramers, essentially containing more shorter carbon chains, as evidenced by low branching proximity and low free carbon index, with the number of methyl branches per molecule (0.9) and by C₁₆The amount of hydrogenated oligomers produced by NAO was about the same.

Due to the more extensive hydroisomerization (examples 8-3) applied during the refining step, our low viscosity base oils exhibit much lower branching proximity and free carbon index, as well as higher branching index and higher number of methyl branches per molecule. From C₁₆Example 8-3 made of NAO now compares with C₁₀The 4cSt PAO made from NAO has a higher number of methyl branches per molecule. This indicates that methyl migration occurred during the hydroisomerization.

Example 9Process for manufacturing high quality low viscosity base oils for high yield and superior product properties

The overall process can be further optimized by combining the high conversion and selectivity achieved by the high temperature oligomerization step and the hydroisomerization step using zeolite catalysts in order to produce very high quality base oils.

Examples 3-5 shown in Table 10 show the properties of base oils (reference case) made by oligomerization at 100 ℃ followed by hydrogenation with a Pt, Pd/alumina catalyst.

Higher temperature oligomerization at 130 ℃ and 150 ℃ was carried out for examples 9-1 to 9-3. In example 9-1 (reference case), the oligomer was then hydrogenated using a Pt, Pd/alumina catalyst, while in examples 9-2 and 9-3 (invention), the oligomer was subjected to a hydroisomerization refining step. The process conditions, product yields and property data are summarized in table 10.

Watch 10

Process for making high quality base oils for superior product properties from C₁₆ ^＝Physical Properties of high quality base oils made from NAO

As seen in the other examples, hydrogenation C₁₆ ^＝The oligomers (examples 3-5 and 9-1) exhibited excellent viscosity index and Noack volatility, but poor low temperature performance (poor pour and cloud points, and poor cold start simulator viscosity). The hydrofinishing step using a Pt, Pd/alumina catalyst (not a strong acid) did not crack the oil and the yield of finished lubricant from the hydrogenation step was about 100%.

The hydroisomerization refining step using a zeolite catalyst cracks some of the hydrocarbon molecules into lighter products (off-gas, gasoline, and diesel range products), and this is undesirable because it reduces lubricant yield. Since hydrocracking increases with increasing temperature, it is desirable to carry out the hydroisomerization at as low a temperature as possible or under as mild conditions as possible while meeting the product requirements.

In example 9-2, the pour point was further reduced to-47 ℃ by hydroisomerization refining at 288 ℃, but the base oil yield was reduced to 92%. In example 9-3, the pour point was reduced to-38 ℃ by hydroisomerization refining at 277 ℃, with a base oil yield of 95.9%. Both samples exhibited excellent Cold Cranking Simulator (CCS) viscosity at-35 ℃ (1302cP and 1428cP) and Micro Rotary Viscometer (MRV) viscosity at-40 ℃ (2,006cP and 58,557cP)

The results in Table 10 show that the mild hydroisomerization refining step, which follows the high temperature oligomerization, is performed from high molecular weight NAO (C)₁₄-C₂₄NAO) an efficient way to synthesize high quality low viscosity base oils while maximizing overall base oil yield and base oil product quality.

Example 10Molecular Structure analysis of our high quality Low viscosity base oils

The analysis of the composition of the hydrogenated or hydroisomerized products from examples 9-1 to 9-3 was performed using nuclear magnetic resonance spectroscopy (NMR) and is reported in table 11 below.

TABLE 11

Relationship between average molecular Structure and Low viscosity base oil Properties from n-C Using Ionic liquid catalysts₁₆ ^＝Comparison of NAO-produced Low viscosity oil with 4cSt PAO

From C₁₆ ^＝Low viscosity base oils made by NAO oligomerization (example 9-1) contain more ε CH₂I.e. higher branching proximity and free carbon index, which contributes to higher VI but also to very poor low temperature properties. From C₁₀The 4cSt PAO made from NAO comprises mainly trimers and tetramers and essentially more shorter carbon chains as evidenced by low branching proximity and low free carbon index, with the number of methyl branches per molecule (0.9) and by C₁₆The amount of hydrogenated oligomers produced by NAO was about the same.

Due to the more extensive hydroisomerization (examples 9-2 and 9-3) applied during the refining step, our low viscosity base oils exhibit much lower branching proximity and free carbon index, as well as higher branching index and higher number of methyl branches per molecule. From C₁₆Examples 9-2 and 9-3 made of NAO are now compared with C₁₀4cSt PAO made with NAO has higher methyl branches per molecule (2.4 and 2.0 vs. 0.9). This again indicates that methyl migration is a key mechanism for improving product quality. Isomerization occurs during both high temperature oligomerization and hydroisomerization.

Example 11Compositional analysis of the molecular Structure of our high quality Low viscosity base oils

Reported in tables 5, 9 and 11All NMR structural data are plotted in fig. 5 to show the effect of changes in molecular structure using our method. Since we changed the method: (1) oligomerization at elevated temperature using preferred ionic catalysts followed by (2) a finishing hydroisomerization step using a metal-containing medium pore zeolite catalyst to remove carbon monoxide from the product C₁₆The NAO monomer produces a high quality low viscosity base oil, so there is a substantial change in the molecular structure, especially in the branching proximity, from 33.4 to 18.1.

Each structural parameter (branching index, number of methyl branches per molecule, and free carbon index) is plotted against branching proximity. The results in fig. 5 clearly show that the molecular structural changes decline with a consistent trend, and we can clearly distinguish our invention from the preferred invention region. These graphs show that₁₆High quality low viscosity base oil made from NAO and blend of C₁₀The composition of commercial 4cSt PAO made from NAO is quite different. Here we define the composition of the low viscosity base oil made by our process.

The viscosity index and pour point of our products in tables 5, 9 and 11 are plotted in figure 6 against the branched proximity NMR structural data. The results in fig. 6 clearly show that the improvement in the properties of the low viscosity base oil is closely related to the change in the molecular structure, and we can clearly distinguish our invention from the preferred invention region. These graphs show that the invention is invented by our method from C₁₆High quality low viscosity base oil made from NAO and blend of C₁₀The composition of commercial 4cSt PAO made from NAO is quite different. Here we define the key properties of the low viscosity base oil made by our process.

Invented by our method from C₁₆High quality low viscosity base oil made from NAO and blend of C₁₀The composition of commercial 4cSt PAO made from NAO is quite different. Here we define the key properties of the low viscosity base oil made by our process.

C₁₆Dimeric and aromatic compounds of formula C₁₀The major disadvantage of commercial 4cSt made from trimers is the low temperature performance. Using the method of our invention, we overcome the use of C₁₆NAO, and can produce a premium low viscosity base oil with excellent low temperature properties, as observed in excellent pour and cloud points and CCS and MRV viscosities.