Oligomerization process of linear alpha olefin to produce base stock

Abstract

Linear alpha olefins of carbon number 10 and heavier are upgraded over a solid acid catalyst in an oligomerization process followed by hydrogenation to provide hydrogenated oligomers having Group II+ and Group / III base stock properties for subsequent use in a lubricant formulations and other applications.

Description

OLIGOMERIZATION PROCESS OF LINEAR ALPHA OLEFIN TO PRODUCE BASE STOCKCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 613,516 filed on December 21, 2023, the entire contents of which is incorporated herein by reference.FIELD

[0002] The present disclosure relates to dimerization of Ci4- linear alpha olefin and mixtures thereof in an oligomerization process to produce hydrogenated oligomers useful as a base stock having Group IU7Group III base stock properties.BACKGROUND

[0003] Higher molecular weight linear alpha olefin (“LAO”) of C12 and heavier carbon numbers are often used as feedstock for producing lowly branched alcohols for surfactant applications and the heaviest LAO (C20 - C24 and C241) fractions useful in synthetic wax applications such as candles, crayons, extrusion aids. Recent efforts to upgrade the LAO of C12+ beyond chemical intermediates or surfactant application through dimerization into synthetic base stocks have had significant challenges and therefore are not commonly practiced commercially.SUMMARY

[0004] Provided herein is a process for producing a base stock comprising providing a LAO feedstock comprising a C14+ LAO; contacting the LAO feedstock with a solid acid catalyst to produce an oligomerization mixture comprising a C14+ LAO dimer and a monomer, separating the C14+ LAO dimer from the monomer in the oligomerization mixture in a distillation process; and hydrogenating the C 14+ LAO dimer to produce a base stock having a viscosity between 2.7 and 3.5 KV100 and 12 cSt and 15 cSt KV40 as measured by ASTM test method D445 and a viscosity index greater than 100 as measured by ASTM test method D2270. The solid acid catalyst is a MWW framework type zeolite.

[0005] Also provided is a process for producing a plurality of synthetic hydrocarbons comprising: providing a LAO feedstock comprising a LAO and mixtures thereof, contacting the LAO feedstock with a solid acid catalyst to produce an oligomerization mixture comprising at least one dimer of the LAO and a monomer; separating the LAO dimer from the monomer, and hydrogenating the dimer of the LAO to produce the plurality of synthetic hydrocarbons having a viscosity between 2.7 and 3.5 KV100 and 12 cSt and 15 cSt KV40 as measured by ASTM test method D445 and a viscosity index greater than 100 as measured by ASTM test method D2270. The LAO is in liquid phase and the solid acid catalyst is an MWW -type zeolite.

[0006] These and other features and attributes of the disclosed catalyst complexes and methods of the present disclosure and their advantageous applications and / or uses will be apparent from the detailed description which follows.BRIEF DESCRIPTION OF DRAWINGS

[0007] To assist those of ordinary skill in the relevant art in making and using the subject matter hereof, reference is made to the appended drawings, wherein:

[0008] FIG. 1A is a chart that shows the selectivity of a solid acid catalyst, ZSM-57 to produce various linear and branched hydrocarbons and its activity with respect to Ci4 LAO conversion at three different temperatures and two different feedstock flow rates.

[0009] FIG. IB is a chart that shows the selectivity of a solid acid catalyst ZSM-23 to produce various linear and branched hydrocarbons and its activity with respect to Ci4 LAO conversion at three different temperatures and two different feedstock flow rates.

[0010] FIG. 1C is a chart that shows the selectivity of a solid acid catalyst MCM-49 to produce various linear and branched hydrocarbons and its activity with respect to Ci4 LAO conversion at three different temperatures and two different feedstock flow rates.

[0011] FIG. ID is a chart that shows the selectivity of a solid acid catalyst HPW to produce various linear and branched hydrocarbons and its activity with respect to Ci4 LAO conversion at three different temperatures and two different feedstock flow rates.

[0012] FIG. 2 is a chart showing the Ci4 LAO dimerization selectivity, Ci4 LAO conversion and yield of each of the solid acid catalysts ZSM-57, ZSM-23, MCM-49 and HPW.

[0013] FIG. 3 provides a conversion and selectivity profde of dimer produced by the present process as described in the examples and using a solid acid catalyst MCM-49.

[0014] FIG. 4 is a chart that summarizes a carbon number distribution for each collected distillation fraction of the process described in the examples and a final heart-cut of a total reactor effluent.

[0015] FIG. 5 is a reconstructed distillation curve of the present process described in the examples including (open circles) and excluding (closed circles) the added Primol 542 bottoms.DETAILED DESCRIPTION

[0016] Before the present compounds, components, compositions, and / or methods are disclosed and described, it is to be understood that unless otherwise indicated this disclosure is not limited to specific compounds, components, compositions, reactants, reaction conditions, ligands, catalyststructures, or the like, as such may vary, unless otherwise specified. It is also to be understood that the terminology used herein is for the purpose of describing different embodiments and is not intended to be limiting.

[0017] All numerical values within this detailed description and claims should be considered modified by “about” or “approximately” the indicated value to account for experimental error and variations.

[0018] For the sake of brevity, only certain ranges are explicitly disclosed herein. However, ranges from any lower limit may be combined with any upper limit to recite a range not explicitly recited, as well as ranges from any lower limit may be combined with any other lower limit to recite a range not explicitly recited, in the same way, ranges from any upper limit may be combined with any other upper limit to recite a range not explicitly recited. Additionally, within a range includes every point or individual value between its end points even though not explicitly recited. Thus, every point or individual value may serve as its own lower or upper limit combined with any other point or individual value or any other lower or upper limit, to recite a range not explicitly recited.

[0019] For the purposes of this disclosure, the following definitions will apply:

[0020] As used herein, the terms “a” and “the” as used herein are understood to encompass the plural as well as the singular.

[0021] For purposes of this invention and the claims hereto, the numbering scheme for the Periodic Table Groups is according to the IUPAC Periodic Table of Elements as of Jan. 1, 2020.

[0022] The term "and / or" as used in a phrase such as "A and / or B" herein is intended to include "A and B", "A or B", "A", and "B".

[0023] As used herein, the term "alpha-olefin" refers to an olefin having a terminal carbon-to- carbon double bond ((RIR2)-C=CH2) in the structure thereof.

[0024] The term “base stock” is a lubricant component that is produced by a single manufacturer to the same specifications (independent of feed source or manufacturer’s location), meets the same manufacturer’s specification, and is identified by a unique formula, product identification number or both. American Petroleum Institute (API) 1509, Engine Oil Licensing and Certification System, 15thed., April 2002, Appendix E. API Base Oil Interchangeability Guidelines for Passenger Cr Motor Oils and Diesel Engine Oils, 2004, Section E.1.2, Definitions (Washington, DC: American Petroleum Institute).

[0025] Unless otherwise specified, the term "hydrocarbon" refers to a class of compounds containing hydrogen bound to carbon, and encompasses (i) saturated hydrocarbon compounds, (ii)unsaturated hydrocarbon compounds, and (iii) mixtures of hydrocarbon compounds (saturated and / or unsaturated), including mixtures of hydrocarbon compounds having different values of n.

[0026] The term “Cn” or “Cn hydrocarbon,” where n is a positive integer, means (i) any hydrocarbon compound comprising carbon atom(s) in its molecular structure having n total carbon atom, or (ii) any mixture of two or more such hydrocarbon compounds in (i). Any degree of unsaturated may be present in such Cn hydrocarbons. For example, unless otherwise specified, a C2 hydrocarbon may refer to ethane, ethylene, acetylene, or mixtures of at least two of these hydrocarbons at any proportion.

[0027] The term “Cn+ hydrocarbon” means (i) any hydrocarbon compound comprising n or greater carbon atom(s) in its molecular structure, or (ii) any mixture of two or more such hydrocarbon compounds in (i).

[0028] As used herein, the terms “paraffin,” “alkane,” and “saturated hydrocarbon” are synonymous with one another and refer to hydrocarbons having a formula of CnH2n+2.

[0029] As used herein, the terms “linear” and “normal” are synonymous with one another and refer to hydrocarbons without side-chain branches.

[0030] As used herein, the term “cracking” refers to the conversion of a given hydrocarbon molecule into two smaller hydrocarbon molecules.

[0031] As used herein, the term “isomerization” refers to a skeletal rearrangement of a hydrocarbon, particularly conversion of a normal paraffin into a branched paraffin.

[0032] As used herein, the term “weight hour space velocity” (WHSV) refers to a measure of the weight of a feed mixture flowing per unit weight of a catalyst per hour.

[0033] As used herein, the term “liquid hour space velocity” (LHSV) refers to a measure of the volume of a feed mixture flowing per unit volume of a catalyst per hour.

[0034] As used herein, a "lubricant" refers to a substance that can be introduced between two or more moving surfaces and lowers the level of friction between two adjacent surfaces moving relative to each other.

[0035] As used herein, an "olefin" refers to an unsaturated hydrocarbon compound having a hydrocarbon chain containing at least one carbon-to-carbon double bond in the structure thereof, wherein the carbon-to-carbon double bond does not constitute a part of an aromatic ring. The olefin can be straight-chain, branched-chain or cyclic. "Olefin" is intended to embrace all structural isomeric forms of olefins, unless it is specified to mean a single isomer or the context clearly indicates otherwise.

[0036] As used herein, the term “viscosity index” or “VI” is a measure of the extent of viscosity change with temperature; the higher the VI, the less change, and generally speaking, higher Vis are preferred. VI is usually calculated from measurements at 40 °C. and 100 °C. The minimum VI for a paraffinic base stock is typically between about 80 and about 95, as established by automotive market needs.

[0037] As used herein, the term “pour point” is the temperature at which a base stock no longer flows. For paraffinic base stocks, pour points can be between about -12 °C. and about -15 °C., as determined by operation of the dewaxing unit. For specialty purposes, pour points can be much lower. The pour points of naphthenic base stocks, which can have very low wax content, may be much lower (-30 °C. to -50 °C.). For very viscous base stocks such as Bright stocks, pour points can reflect a viscosity limit. Pour points are measured by ASTM D97.

[0038] As used herein, the term “MWW -type zeolite MCM-49” is interchangeable with the terms “MCM-49,” “zeolite MCM-49” and “as-synthesized MCM-49.”

[0039] As used herein, a “crystalline microporous material of the MWW framework type” includes one or more of: (1) molecular sieves made from a common first-degree crystalline building block unit cell, which unit cell has the MWW framework topology having a unit cell is a spatial arrangement of atoms which if tiled in three-dimensional space describes the crystal structure such crystal structures are discussed in the “Atlas of Zeolite Framework Types,” Fifth edition, 2001; (2) molecular sieves made from a common second degree building block, being a 2-dimensional tiling of such MWW framework topology unit cells, forming a monolayer of one unit cell thickness, preferably one c-unit cell thickness; (3) molecular sieves made from common second degree building blocks, being layers of one or more than one unit cell thickness, wherein the layer of more than one unit cell thickness is made from stacking, packing, or binding at least two monolayers of MWW framework topology unit cells where the stacking of such second-degree building blocks can be in a regular fashion, an irregular fashion, a random fashion, or any combination thereof; and (4) molecular sieves made by any regular or random 2-dimensional or 3-dimensional combination of unit cells having the MWW framework topology.

[0040] As used herein, the term “variable oxidation state metal” refers to a metal having two or more accessible oxidation states other than zero oxidation state.

[0041] As used herein, the term “total surface area” refers to the total specific external and internal surface area of disperse or porous solids (microporous materials), which is obtained by measuring the amount of physically adsorbed N2 adsorption / desorption isotherms, such as specified in ISO 9277.

[0042] As used herein, the term “collidine uptake” refers to the millimoles of collidine (a type of catalyst poison) absorbed per gram of sample. In a non-limiting example, the sample may be dried under nitrogen flow at 200°C for 60 minutes on a Thermogravametric Analyzer (Model Q5000, manufactured by TA Instruments, New Castle, Delaware) before exposing the sample to collidine and measuring the amount of adsorbed collidine gravimetrically.

[0043] The term, linear alpha olefin (“LAO”), also referred to as a terminal olefin or terminal alkene, means a linear hydrocarbon that has a chemical formula of Cxfhx where x is an integer greater than or equal to 2 and a double bond between the first carbon (C-l) and the second carbon (C-2).

[0044] LAOs are often isolated from a petroleum refinery stream. Alternatively, linear alpha olefins are synthesized from low molecular weight feedstock materials, such as via metathesis reaction of ethylene, or through byproduct isolation from the Fischer-Tropsch synthesis. Biomass- derived linear alpha olefins and linear alpha olefins are also available from other sources. Industrially, linear alpha olefins are typically manufactured by oligomerization of ethylene or by Fischer-Tropsch synthesis followed by purification. On a small scale, another route to linear alpha olefins used commercially is dehydration of alcohols.

[0045] Lower carbon number LAOs are used as comonomer in production of polyethylene. For example, C4 to LAO are monomers used in co-polymerization processes to produce linear low- density polyethylene (“LLDPE”). C4 to Cs LAO is also used to produce linear aldehyde via oxo synthesis (hydroformylation) for later production of short-chain fatty acid, a carboxylic acid or linear alcohols for plasticizer application by hydrogenation of the aldehyde. Further, a predominant application of C10 LAO is a feedstock for production of poly alpha olefins (“PAOs”) which are then blended into a high-performance lubricant formulation. LAO C4 to C12 are also used for hydroformylation or alkylation and further processing to surfactants.

[0046] In a dimerization process, C4+ LAO is a preferred feedstock. However, C4to C10 LAO is an expensive commercial feedstock and in high demand. Prior art dimerization processes of C12+ LAO, include metathesis, Lewis Acid (BF3) or metallocene-based (homogeneous) catalyst routes. See e.g., US Published Application No. 2023 / 0127018 and W02020 / 068527. These processes utilizing feedstocks of LAOs having larger carbon numbers are relatively cost intensive in comparison with oligomerization over solid acid catalysts.

[0047] For example, dimerization of linear alpha olefins with a metal carbene catalyst afford formation of linear olefin dimers by a metathesis reaction and commensurate loss of ethylene. A single linear alpha olefin may self-dimerize to form the linear olefin dimers or two different linearalpha olefins may form asymmetrical linear olefin dimers. Mixtures of linear olefin dimers having different carbon chain lengths may also be formed in this manner. Linear olefin dimers comprise two carbon atoms less than a total number of carbon atoms in linear alpha olefins from which they were produced (as a result of ethylene loss). US20230127018 Al at

[0017] ,

[0048] Processes of LAOs dimerization via metathesis comprise the need of purifying the olefinic feed to remove one or more contaminants therefrom. Purification may mitigate the presence of one or more contaminants therein (e.g., oxygenates, moisture, metals, heteroatoms, and any combination thereof), particularly during metal carbene catalyst preforming of a metathesis process (e.g., dimerization). Purifying may comprise contacting the feed with an adsorbent, sparging the feed with an inert gas, or any combination thereof in the same or different location(s), and purifying the linear olefin dimer(s) from light species and unreacted feed by distillation / flashing and / or falling-film evaporation, thereby limiting the quantity of contaminants returned to the metathesis reaction upon recycling the feed. US20230127018 Al at T|

[0067] .

[0049] Further, since the metathesis reaction is reversible, formation of linear olefin dimers requires the removal the ethylene produced during the metathesis reaction. Removing the ethylene may drive the reaction equilibrium toward linear olefin dimer products. For instance, during the metathesis reaction, concurrent stripping and removal of ethylene gas is performed. Ethylene stripping is conducted using a stream of inert gas, sparging the reaction products with inert gas, or applying a partial vacuum. See e.g., US20230127018 Al at

[0078] ,

[0050] Moreover, during the metathesis reaction, deactivated metal carbene catalyst and metal carbene catalyst residue can act as poisons toward the fresh catalyst. The spent catalyst (e.g., transition metals, ligands, or any combination thereof) needs to be removed from the reaction product. The spent catalyst may be further deactivated by using a quenching treatment comprising a vinyl halide or vinyl ether (e.g., ethyl vinyl ether), for example. US20230127018 Al at ^|

[0080] ,

[0051] The present processes produce a hydrogenated oligomer and / or a plurality of hydrogenated oligomers (a plurality of synthetic hydrocarbons) without cooling or quenching prior to the step of separating the dimer from the monomer The hydrogenated oligomers produced are useful as a base stock. The present process offers a route to upgrade LAO of carbon number 10 and higher, beyond chemical intermediate or surfactant applications, by dimerization into a synthetic hydrocarbon to produce a base stock having Group II+ / III base stock properties for a high performance / cost ratio base stock product. In an embodiment, the present processes have an advantage of producing a base stock with using a C14+ LAO feedstock at reduced costs.

[0052] The feedstock of the present process comprises one or more of the following: C10+ LAO monomer, C12+ LAO monomer, C14+ LAO monomer, and / or Ci6+ LAO monomer; a mixture of one or more of C10+ monomer, C12+ LAO monomer, C14+ LAO monomer, and / or Ci6+ LAO monomer; and a mixture of C10+ LAO, C12+ LAO, C14+ LAO, Ci6+ LAO and / or C LAO or higher. In an embodiment, the feedstock is a mixture of LAOs having a molar ration of 1 : 1 : 1 of C12 LAO, C14 LAO and Ci6 LAO. In an embodiment, the feedstock is a mixture of LAOs having a molar ratio of 1 :2: 1 of C12 LAO, C14 LAO and Ci6 LAO. In an embodiment, the feedstock is a mixture of LAOs having a molar ratio of 1 :2:3 :2: 1 of C10 LAO, C12 LAO, C14 LAO, Ci6 LAO and / or Cis LAO.

[0053] As provided herein, the LAO of carbon number 14 or higher and mixtures including C10 LAO, C12 LAO, Ci4 LAO, Ci6 LAO and / or C is LAO is converted over a solid acid catalyst, by combined dimerization and isomerization of the olefins, followed by hydrogenation to produce a plurality of synthetic hydrocarbons, also referred to herein as hydrogenated oligomers, having properties similar to Group II+ / III base stock. As described herein, the solid acid catalysts include MWW framework type zeolites, preferably MCM-49.

[0054] Generally, polymerization of linear alpha olefin monomer molecules in the presence of a catalyst system can produce a multitude of molecules with different degrees of oligomerization. Thus, an oligomer can be a dimer (resulting from two terminal olefin molecules), a trimer (resulting from three terminal olefin molecules), a tetramer (resulting from four terminal olefin molecules), or any other oligomer or polymer comprising two or more structure units derived from one or more terminal olefin monomer(s). As described herein, oligomerization conditions influence the distribution of oligomers resulting from the process. An oligomerization process is typically conducted in the presence of a catalyst system and in a temperature range between 120 °C and 220°C and at pressures up to 300 bar.

[0055] The oligomerization process steps include : (i) providing an LAO feedstock comprising C10. C12, and / or C14+ LAO and / or mixtures thereof; (ii) contacting the LAO feedstock with a catalyst system in at least one oligomerization reactor under oligomerization conditions to obtain an oligomerization reaction mixture comprising unreacted olefin monomer(s), dimers, and higher oligomers, and the catalyst system; (iii) separating the unreacted monomer(s) from the oligomerization reaction mixture to obtain an unsaturated product precursor; and (iv) hydrogenating the unsaturated product precursor in a hydrogenation reactor in the presence of hydrogen under hydrogenation conditions to obtain a hydrogenated oligomer (a synthetic hydrocarbon). Optionally, the hydrogenated oligomer undergoes a second distillation step. Optionally, the monomer is recycledas the feedstock. The hydrogenated oligomer (i.e., dimer and optionally other oligomer) is useful as a base stock and more specifically, a base stock having properties of a Group 11+ or Group III base stock.

[0056] Certain key features of the hydrogenated oligomers (a plurality of synthetic hydrocarbons) produced by the present processes include one or more of the following properties: (a) between 2.7 cSt and 3.5 cSt KVIOO as measured by ASTM test method D445; (b) between 15.0 cSt and 12.0 cSt KV40 as measured by ASTM test method D445; (c) a viscosity index greater than 100 as measured by ASTM test method D2270; (d) a Noack volatility of less than 30 wt.% as measured by ASTM test method D5800; (e) a pour point of less than -60°C as measured by ASTM test method D5960; (f) a Cold Crank Simulator (CCS) at 30 °C of less than 600 cP as measured by ASTM test method D5293; and (g) a flash point of greater than 200 °C. The hydrogenated oligomers as a base stock are useful in a synthetic lubricant formulation (also referred to herein as a lubricant formulation).

[0057] In an embodiment, the base stock comprising the C14+ LAO dimer has a Cn hydrocarbon distribution and a predominant Cn hydrocarbon that is narrower than reported Group 11+ or Group III base stock. As shown in Table 1 below, the Cn hydrocarbon distribution and the predominant Cn hydrocarbon of the C14+ LAO dimer produced with the present process is compared with a reported Cn hydrocarbon distribution and predominant Cn hydrocarbon for each of Group II+and Group III.Table 1

[0058] As provided in Table 1, the Cn hydrocarbon distribution represents a normal distribution. Also, the predominant Cn hydrocarbon represents the Cn hydrocarbons present in the highest proportion. When compared with reported data of Group II1base stock and Group III base stock, the C14+ LAO hydrogenated dimer produced by the present processes have a narrow distribution. See, Lee, S. et al. Chemical Composition of Group II Lubricant Oil Studied by High-Resolution Gas Chromatography and Comprehensive Two-Dimensional Gas Chromatography . Energy Fuels 2007, 21, 6, 3477-3483.

[0059] The narrow distribution of Cn hydrocarbons is one of several advantages provided by the present process. Further, it is desirable to provide olefin feed streams that can be oligomerized at highefficiency / high yield and run for an extended period without causing early replacement or regeneration of catalyst. Moreover, it is desirable to take advantage of an olefin feed stream which needs little pretreatment for use in an oligomerization system. The present processes provide each of these advantages.

[0060] Oligomerization of olefin compounds is conventionally accomplished by catalytic reaction. As described herein, the present oligomerization catalysts are solid acid based catalysts where the process is preferably carried out in a flow-through, fixed bed type of arrangement. In the present process, dimer molecules isomerize to form terminal or internal olefins. Some of the dimer molecules or isomers further react with one additional monomer molecule to form trimer molecules. Some of the dimer molecules or isomers react with each other to form tetramer molecules. The trimer molecules may react with one additional monomer molecule to form tetramers. Higher oligomers than tetramers can be formed as well. W02020 / 068527 Al at

[0064] ,

[0061] As provided herein, the present process includes a heterogenous catalyst. The heterogenous catalyst and / or oligomerization mixture does not require a quenching or cooling prior to hydrogenation of the oligomer, saving energy and manufacturing costs of producing the base stock. In addition, the solid acid base catalyst used in the present processes does not require a separation step or need to be separated from the oligomerization mixture. The lack of this separation process also saves energy and manufacturing costs. Further, after separation, the monomer can be recycled and provided as the feedstock

[0062] The present processes comprise the step of dimerizing Ci4+ LAO and / or mixtures thereof over one or more solid acid catalyst in an isothermal fixed bed type reactor. The C14+ LAOs have a relatively high boiling point and high molecular weight. As such, until the present disclosure, dimerization of C14+ LAO over solid acid catalysts has had significant challenges. First, there was a greater yield loss because of a high selectivity for cracked dimer products. Second, as a general matter, higher molecular weight of C14+ LAO feedstock cause the feedstock to remain in a liquid phase at reaction conditions, resulting in mass transfer limitations and faster catalyst deactivation by coking. See e.g., Wulfers, M. et al., Assessment of Mass Transfer Limitations in Oligomerization of Butene at High Pressure on H-Beta, Applied Catalysis, Vol. 505, 394-401 (2015); Corma, A, et al., Designing MFI-Based Catalysts with Improved Catalyst Life, Journal of Catalysis, Vol. 300, 183-196 (2013); Peratello, S. et al., Olefins Oligomerization: Thermodynamics and Kinetics Over Mesoporous Silica- Alumina, Catalysis Today, Vol. 52, 271-277 (1999); Catalysis: An Integrated Approach, Vol. 123, (1999) at 426. At higher molecular weight, diffusion rates are lower and internal mass transferlimitations have a greater impact. Therefore, dimerization of C14+ dimerization versus dimerization / oligomerization of feedstocks of lower carbon number (i.e., a carbon number of 10 or less) is not commonly practiced commercially.

[0063] Generally, a primary deactivation mechanism (without presence of feed poisons) is the formation of heavy hydrocarbons and coke (high molecular weight polyaromatic hydrocarbon species) which block access to zeolite pores and active sites. Other effects include irreversible adsorption of basic species, oxygenates, sulfur, and the like. However, these effects can be managed and / or excluded. As shown in the examples below, a slower deactivation (dimerization of heavy C14+ feed using MWW type materials) is due to the high acid site density (vs. HPW catalyst) and higher accessibility (vs. ZSM-57 / ZSM-23) of the MWW type 12 ring pockets, resulting in quicker desorption of formed dimer molecules before they can react further to form high molecular weight species that block active sites and access to pores.

[0064] As described herein, we have discovered that a high active site accessibility of a solid acid catalyst is key. Low Si / Ah ratio in combination with high surface area are shown to be favorable for high conversion of the C10+ LAO feedstock to a synthetic hydrocarbon with good base stock properties. Acid site accessibility as quantified by thermogravimetric analysis (TGA) total uptake of e.g. substituted pyridine too large to enter micropores, such as 2,4,6-trimethylpyridine (collidine) was shown to be key in obtaining high sustained conversion and selectivity.Fixed Bed Reactor Followed by Hydrogenation

[0065] As described in the examples, our catalyst testing experiments were run on a bench scale fixed-bed reactor. The unit was equipped with a high temperature ISCO liquid pump for feeding (heavy) liquids and nitrogen and hydrogen gases for pretreatment. The reactor, a 9 mm diameter 100 mm length tube, is placed in a heated oven with a thermocouple located inside the catalyst bed for accurate temperature control. All catalyst was crushed and sieved to a 300 - 600 micron sieve fraction and typically 1 - 5 g catalyst was loaded and mixed with SiC for improved heat transfer and reactor flow distribution. All dimerization catalyst testing experiments were run in a reactor up flow configuration. C14 Linear Alpha Olefin (Linealene 14, Idemitsu Kosan Co. Ltd.) feed was used in all experiments and 1 wt.% dodecane (Sigma-Aldrich, > 99%) was added as an internal standard. Product analysis was performed by online GC using an Agilent 7890A instrument equipped with a 15 m x 250 pm x 0.25 pm RTX-1 (boiling point) column.

[0066] For commercial processes both adiabatic or isothermal (e.g. boiling water reactors) fixed bed or continuous stirred tank reactors can be considered. See US Pat. Nos. 5,567,280, 6,884,914, andUS Pub. App. 2020 / 0102256 for exemplary process / reactor configuration descriptions.Hydrogenation of LAO Dimers

[0067] Hydrogenation of the linear olefin dimers described above may be carried out in any suitable manner in a slurry or fixed bed reactor system using a variety of Ni, Pt or Pd hydrogenation catalysts. Suitable hydrogenation conditions, hydrogenation catalysts, reactors and the like will be familiar to one having ordinary skill in the art. Reactors suitable for hydrogenation of the linear olefin dimers include, but are not limited to batch reactors, plug-flow reactors, and liquid continuous mode reactors. When the reactor is a liquid continuous mode reactor, the hydrogenated reaction product (hydrogenated oligomers) can be recycled with a fresh feed of the linear olefin dimers and flashed to carry sufficient hydrogen dissolved therein to perform the hydrogenation reaction. Such system configurations may simplify the reactor design. See e.g., US20230127018 Al

[0065] ,

[0068] As described in the examples, hydrogenation of distilled hydrocarbon heartcut was carried out on in a fixed bed catalytic reactor. 2 grams (g) of pre-reduced CO2 passivated massive Ni catalysts (Ni3298, BASF) was activated according to the following procedure: initial heating ramp of 2 °C min-1 up to 100 °C, 5 °C min-1 up to 200 °C and holding for 6 hours all under hydrogen flow, before lowering the temperature (10 °C min-1) to the initial reaction conditions and introducing the feed. An initial hydrogenation experiment was run at weight-hourly space velocity (“WHSV”) 10 h-1 and 100 °C at 16 barg pressure and H2 to olefin ratio of 2 (assuming an average olefin molar weight of 392 g.mol'1). After tests showed that a significant amount of the olefins was left unhydrogenated, a second hydrogenation was carried out at a WHSV of 1 h-1 and 150 °C at a H2 to olefin molar ratio of 2, in order to completely hydrogenate the material.

[0069] WHSV can be used to optimize selectivity to dimer, unreacted olefin recycle, dilution with paraffin stream to manage heat generation in reactor / deactivation and optimize selectivity to dimer, temperature range. These parameters can be also used to optimize the branchiness of the formed dimer as well, which is important for the final properties. Other process parameters can be varied including olefin feedstock, the catalyst and catalyst load, reaction temperatures, process time, catalyst removal efficiency, and any fractionation conditions. Each of these parameters can be optimized to meet target molecular properties.Optimization of the Solid Acid Catalyst

[0070] Zeolite catalysts are applied in hydrocarbon processing and in chemical conversion processes. Properties that make zeolites versatile catalyst components are: size and shape of the crystallites are variables in catalyst design and are determined by the synthesis conditions. Theinternal surface area is high and thermally very stable compared to those of the amorphous silicas and aluminas used traditionally in catalyst preparation. The pores are well defined and of molecular dimensions, the pore size is determined by the crystallographic structure. The pore openings ruling the accessibility of the internal surface may be subtly changed by ion-exchange, post impregnation or chemical reaction with specific compounds, (pore size engineering). Charge-compensating cations can be removed by ion exchange. T-atoms are in most structures highly accessible; their nature determines the polarity of the surface and its catalytic activity. The chemical composition of the lattice is dependent on the synthesis conditions. In many cases, the Si / AI ratio may be varied within wide limits and for some structures, also the nature of the T-atoms is a variable

[0071] Catalyst formulations can be optimized in a very versatile way. Active phase %, binder pore size distribution, zeolite crystal size, Si / Ah ratio are all examples parameters that can be optimized for maximum activity, selectivity, and catalyst life. See generally, Concepts for Preparation of Zeolite-Based Catalysts, Synthesis of Solid Catalyst, Chapter 12, Wiley Online (2009); See also, Preparation of Zeolite Catalysts, Studies in Surface Science and Catalysis, Volume 137 (2001) at 673-706.

[0072] An “active phase” is the content of zeolite or heteropolyacid phase in the catalyst material, with the balance being binder (AI2O3 or SiO2 in these examples). These are formulated materials, where the active phase is assumed participate in the catalytic reaction and the binder serves the purpose of providing mechanical stability of the catalyst and / or improving dispersion of the active phase.

[0073] High acid site density refers to the low Si / Ah ratio of the MCM-49 catalyst. In aluminosilicate zeolites each framework aluminum atom is assumed to provides a Bronsted acid site, which is active in the acid catalyzed oligomerization reaction. The lower the Si / Ah ratio, the higher the acid site density. The Si / Ah ratio can be measured quantitatively by elemental analysis such as inductively coupled plasma-atomic emission spectroscopy (“ICP-AES”) as provided in the examples or by adsorption / desorption of a base (e.g. ammonia, pyridine, etc.). Accessibility can be measured using various probe molecules as well.

[0074] MWW framework materials including MCM-49 catalyst, have 12 ring openings aligned with the surface of typically thin zeolite crystallites (e.g. “pockets”) that are highly accessible to large molecules versus smaller 10 member ring openings of a framework. Therefore, the 12 member ring “pockets” can accommodate catalysis on large molecules that other porous zeolites, with more constraint pore channel architecture such as ZSM-57 and ZSM-23 cannot. See Lawton, S.L., et al.,Twelve-Ring Pockets on the External Surface ofMCM-22 Crystals, Vol. 23, Issue 1-2 (1998) at 109- 117. ZSM-57 is described in EP 174121 Bl, Col. 2, 1. 23 through Col. 12, 1. 48, incorporated herein by reference. See also, Schlenker, J.L., et al., The Framework Topology of ZSM-57 : A New Synthetic Zeolite, Zeolites, Vol. 10, (1990) at 293-296. ZSM-23 is described in US Pat. No. 4076842, Col. 1, 1. 60 through Col. 6, 1. 44, incorporated by reference. See also, Rohrman, A.C. et al., The Framework Topology of ZSM-23: A High Silica Zeolite, Zeolites Vol. 5, (1985) at 352-354.

[0075] C atalysis by heteropoly acids (HPAs) and related compounds are polyoxometalates incorporating anions (heteropoly anions) having metal-oxygen octahedra as the basic structural units. See Kozhevnikov, Ivan, Heteropoly Acids and Related Compounds as Catalysts for Fine Chemical Synthesis, Science and Engineering, Vol. 37, (1995). The Keggin series HPAs are used in catalysis and include heteropolyanions (HPANs). As described in the example, an HPW catalyst, a Keggintype phosphotungstic heteropolyacid (H3PW12P40, HPW) phase was synthesized by acid condensation from sodium tungstate and sodium phosphate. The phosphotungstic acid (HPW) phase was introduced by impregnation using aqueous incipient wetness impregnation of silica extrudates (PQ Chemicals 1 / 16” extrudates, 229 m2 g-1 surface area and 0.82 cm3 g-1 total pore volume), dried at 110 °C and calcined at 300 °C.Zeolites - Solid Acid Catalyst

[0076] Zeolites are classified by the Structure Commission of the International Zeolite Association according to the rules of the IUPAC Commission on Zeolite Nomenclature. A framework-type describes the topology and connectivity of the tetrahedrally-coordinated atoms constituting the framework and makes an abstraction of the specific properties for those materials. Zeolites can possess an internal pore system that includes interconnected cage like voids or a system of one-, two- or three-dimensional channels. Zeolite adsorbents for which a structure has been established are assigned a three-letter code and are described in the Atlas of Zeolite Framework Types, 5thedition, Elsevier, London, England (2001), which is incorporated in its entirety by reference herein.

[0077] Molecular sieve materials, both natural and synthetic, can be used as adsorbents and have catalytic properties for hydrocarbon conversion reactions. Certain molecular sieves, such as zeolites, AlPOs, and mesoporous materials, are ordered, porous crystalline materials having a definite crystalline structure as determined by X-ray diffraction (“XRD”). Molecular sieves can be ordered and produce specific identifiable XRD patterns. Within certain molecular sieve materials are cavities interconnected by channels or pores. Within a particular type of molecular sieve, the pores aregenerally uniform in size. Pore size determines whether a molecule can travel within the molecular sieve and be adsorbed or rejected.

[0078] Molecular sieves are utilized in a variety of industrial processes, e.g., cracking, hydrocracking, disproportionation, alkylation, oligomerization, and isomerization. Molecular sieves, including naturally occurring or the synthetic crystalline molecular sieves, can find application in catalysis and adsorption.

[0079] Zeolites and their isotypes are classified by the Structure Commission of the International Zeolite Association according to the rules of the IUPAC Commission on Zeolite Nomenclature. According to this classification, framework type zeolites and other crystalline microporous molecular sieves, for which a structure has been established, are assigned a three letter code and are described in the “Atlas of Zeolite Framework Types”, eds. Ch. Baerlocher, L.B. McCusker, and D.H. Olson, Elsevier, Sixth Edition, 2007, which is hereby incorporated by reference.

[0080] Certain zeolites comprise an inorganic framework type where the silicon tetrahedral atoms are connected by oxygen atoms with the four next-nearest tetrahedral atoms. The term “silicate”, as used herein, refers to a substance comprising silicon and oxygen atoms alternately bonded to each other (i.e., -O-Si-O-Si-), and optionally comprise other types of atoms within the inorganic framework type, including boron, gallium, aluminum, or other metals (e.g., transition metals, such as titanium, vanadium, or zinc). Atoms other than silicon and oxygen in the framework occupy a portion of the lattice sites that would be otherwise occupied by silicon atoms in an ‘all-silica’ framework (also referred to as “silicate”). Thus, the term “framework silicate” or “zeolite framework silicate” refers to an atomic lattice comprising silicate, borosilicate, gallosilicate, ferri silicate, aluminosilicate, titanosilicate, zincosilicate, vanadosilicate, and the like. As noted above, the framework structure within a zeolite determines the size of the pores or channels. The pore or channel size determines the type of process for which a given zeolite is applicable. Currently, there are more than 200 known zeolite framework silicates recognized by the Structure Commission of the International Zeolite Association, providing a range of pore geometries and orientations defined.

[0081] The zeolite framework silicate is commonly characterized in terms of ring size, wherein the ring size refers to the number of silicon atoms (or alternative atoms, such as those listed above) that are tetrahedrally coordinated with oxygen atoms in a loop to define a pore or channel within the interior of the zeolite. For example, an “8-ring” zeolite refers to a zeolite having pores or channels defined by 8 alternating tetrahedral atoms and 8 oxygen atoms in a loop. The pores or channels defined within a given zeolite are symmetrical or asymmetrical depending upon various structuralconstraints that are present in the framework silicate.

[0082] Zeolites can be classified as having small, medium, large, and extra-large pore structures for pore windows delimited by 8, 10, 12, and more than 12 T-atoms, respectively. Extra-large pore zeolites (>12R) include, for example, AET (14R, e.g., ALPO-8), SFN (14R, e.g., SSZ-59), VFI (18R, e.g., VPI-5), CLO (20R, e g., cloverite), and ITV (30R, e.g., ITQ-37) framework type zeolites. Extralarge pore zeolites generally have a free pore diameter of larger than about 0.8 nm. Large pore zeolites (12R) include, for example, LTL, MAZ, FAU, EMT, OFF, MTW, *BEA, MOR, and SFS framework type zeolites, e.g., mazzite, offretite, zeolite L, zeolite Y, zeolite X, omega, ZSM-2, ZSM-12, zeolite T, Beta, and SSZ-56. Large pore zeolites generally have a free pore diameter of 0.6 to 0.8 nm. Medium (or intermediate) pore size zeolites (10R) include, for example, MFI, MEL, *MRE, EUO, MTT, MFS, AEL, AFO, HEU, FER, MWW, and TON framework type zeolites, e.g., ZSM-5, ZSM-11, ZSM-48, ZSM-22, ZSM-23, ZSM-35, MCM-22, MCM-49, silicalite-1, and silicalite-2. Medium pore size zeolites generally have a free pore diameter of 0.45 to 0.6 nm. Small pore size zeolites (8R) include, for example, CHA, RTH, ERI, KFI, LEV, and LTA framework type zeolites, e.g., ZK-4, SAPO-34, SAPO-35, ZK-14, SAPO-42, ZK-21, ZK-22, ZK-5, ZK-20, zeolite A, chabazite, and ALPO-17. Small pore size zeolites generally have a free pore diameter of 0.3 to 0.45 nm.

[0083] Synthesis of molecular sieve materials (zeolites) typically involves hydrothermal crystallization from a synthesis mixture comprising sources of all the elements present in the molecular sieve (or zeolite) such as sources of silica but also of alumina etc. In many cases a structure directing agent (“SDA”) is also present. Structure directing agents are compounds which are believed to promote the formation of a molecular sieve and which are thought to act as templates around which certain molecular sieve structures can form and which thereby promote the formation of the desired molecular sieve. Various compounds have been used as structure directing agents including various types of quaternary ammonium cations. Typically, molecular sieve (zeolite) crystals form around structure directing agents with the structure directing agent occupying pores in the molecular sieve once crystallization is complete. The “as-synthesized” (or “as-made”) molecular sieve will therefore contain the structure directing agent in its pores so that, following crystallization, the “as-synthesized” molecular sieve is subjected to a treatment step such as a calcination step to remove the structure directing agent.

[0084] Crystalline microporous materials of the MWW framework type include those molecular sieves having an X-ray diffraction pattern including d-spacing maxima at 12.4±0.25, 6.9±0.15, 3.57±0.07 and 3.42±0.07 Angstrom. The X-ray diffraction data used to characterize the material areobtained by standard techniques using the K-alpha doublet of copper as incident radiation and a diffractometer equipped with a scintillation counter and associated computer as the collection system.

[0085] Examples of crystalline microporous materials of the MWW framework type I or as- synthesized MWW-type zeolite include MCM-22 (described in U.S. Pat. No. 4,954,325), PSH-3 (described in U.S. Pat. No. 4,439,409), SSZ-25 (described in U.S. Pat. No. 4,826,667), ERB-1 (described in European Patent No. 0293032), ITQ-1 (described in U.S. Pat. No. 6,077,498), ITQ-2 (described in International Patent Publication No. WO97 / 17290), MCM-36 (described in U.S. Pat. No. 5,250,277), MCM-49 (described in U.S. Pat. No. 5,236,575), MCM-56 (described in U.S. Pat. No. 5,362,697), UZM-8 (described in U.S. Pat. No. 6,756,030), UZM-8HS (described in U.S. Pat. No. 7,713,513), UZM-37 (described in U.S. Pat. No. 7,982,084; EMM-10 (described in U.S. Pat. No. 7,842,277), EMM-12 (described in U.S. Pat. No. 8,704,025), EMM-13 (described in U.S. Pat. No. 8,704,023), MIT-1 (described by Luo et al in Chem. Sci., 2015, 6, 6320-6324) and mixtures thereof.

[0086] In an embodiment, the crystalline microporous material of the MWW framework type can be an aluminosilicate material having a silica to alumina (Si / Ah) molar ratio of at least 10, such as at least 10 to less than 50.

[0087] As provided herein, the crystalline microporous material of the MWW framework type can be contaminated with other crystalline materials, such as ferrierite or quartz. These contaminants may be present in quantities <10% by weight, normally <5% by weight.Zeolite MCM-49

[0088] As described in US Pat. No. 5,236,575, a MWW-type zeolite MCM-49 (also referred to herein as “zeolite MCM-49” and “MCM-49”) has a composition with a molar relationship as follows: X2O3: (n)YO2 wherein X is a trivalent element, such as aluminum, boron, iron and / or gallium; Y is a tetravalent element such as silicon and / or germanium; and n is less than about 35, Between about 2 and about 35, between about 10 and about 35, between about 15 and about 31. US Pat. No. 5,236,575 at Col. 2, Is 67-68. In the as-synthesized form, the material has a formula, on an anhydrous basis and in terms of moles of oxides per n moles ofYCh, as follows: (0.1-0.6)M20: (l-4)R:X2O3:nYO2 wherein M is an alkali or alkaline earth metal, and R is an organic moiety. The M and R components are associated with the material as a result of their presence during crystallization and are easily removed by post-crystallization methods described in US Pat. No. 5,236,575 at Col. 3, Is 1-20.

[0089] Crystalline material can be prepared from a reaction mixture containing sources of: alkali or alkaline earth metal (M); cation; an oxide of trivalent element X; an oxide of tetravalent element Y; directing agent (R); and water. The composition of the reaction mixture in terms of mole ratios ofoxides is within the following ranges provided in Table 2 below:Table 2Reactants to Produce MCM-49 Zeolite

[0090] In this synthesis method, if more than one X component is present, at least one must be present such that the YO2 / X2O3 molar ratio thereof is less than about 35. For example, if aluminum oxide and gallium oxide components are used in the reaction mixture, at least one of the YO2 / AI2O3 and YO2 / Ga2Os molar ratios must be less than about 35. If only aluminum oxide has been added to the reaction mixture as a source of X, the YO2 / AI2O3 ratio must be less than about 35.

[0091] Also, the source of YO2 is predominantly of solid YO2, for example at least about 30 wt. % solid YO2 in order to obtain the crystal product of the containing at least about 30 wt. % solid silica such as Ultrasil, a precipitated, spray dried silica containing about 90 wt. % silica or Hi Sil, a precipitated hydrated SiCh containing about 87 wt. % silica, about 6 wt. % free H2O and about 4.5 wt. % bound H2O of hydration and having a particle size of about 0.02 micron which favors crystalline MCM-49 formation.

[0092] A directing agent R is selected from the group consisting of cycloalkylamine, azacycloalkane, diazacycloalkane, and mixtures thereof, alkyl comprising from 5 to 8 carbon atoms. Non-limiting examples of R include cyclopentylamine, cyclohexylamine, cycloheptylamine, hexamethyleneimine, heptamethyleneimine, homopiperazine, and combinations thereof. US Pat. 5,236,575 at Col. 6, Is 24-68, at Col. 7, Is. 1-2.

[0093] Synthesizing MCM-49 can be facilitated by the presence of at least 0.01 percent, 0.10 percent and percent of seed crystals based on total weight of crystalline product. Useful seed crystals include MCM-22 and / or MCM-49. US Pat. 5,236,575 at Col. 7, Is 19-23. Also, MCM-49 can be transformed to another form by thermal treatment generally performed by heating at a temperature of at least about 370 °C for at least 1 minute and not longer than 20 hours. While sub-atmospheric pressure can be employed for the thermal treatment, atmospheric pressure is desired for reasons of convenience. The thermal treatment can be performed at a temperature up to about 925 °C. US Pat. No. 5,236,575 at Col. 5, Is 59-67. When employed either as an adsorbent or as a catalyst in an organiccompound conversion process, MCM-49 should be dehydrated, at least partially. This can be done by heating to a temperature in the range of 200 °C to about 370 °C in an atmosphere such as air, nitrogen, etc. and at atmospheric, sub -atmospheric or super-atmospheric pressures for between 30 minutes and 48 hours. Dehydration can also be performed at room temperature merely by placing MCM-49 in a vacuum, but a longer time is required to obtain dehydration. US Pat. No. 5,236,575 at Col. 6, Is 13- 23.Base Stock

[0094] A base stock is generally distinguished by viscosity and produced to certain viscosity specifications. Since viscosity is approximately related to molecular weight, the first step in manufacturing any base stock is to separate out lube precursor molecules from a feedstock having the correct molecular weight range by distillation in a crude fractionation system. As such, lower-boiling fuel products of low viscosities and volatilities that have no application in lubricants are distilled off. Higher molecular weight feedstocks which do not vaporize at atmospheric pressure can be fractionated by distillation at reduced pressure between about 10 mmHg to about 50 mmHg.

[0095] As described above, the higher molecular weight feedstock can then be fed to a vacuum tower where intermediate product streams such as light vacuum gas oil (“LVGO”) and heavy vacuum gas oil (“HVGO”) are produced. These intermediate product streams can be narrow cuts of specific viscosities destined for a solvent refining step, or they can be broader cuts destined for hydrocracking to lubes and fuels.

[0096] Conversely, as described herein, the present processes dimerize Ci4+ LAO over solid acid catalysts in an isothermal fixed bed type reactor to provide a Group 11+ or Group III base stock.

[0097] As provided in Table 3, base stocks are categorized according to the American Petroleum Institute (API) classifications based on saturated hydrocarbon content, sulfur level, and viscosity index. Typically, Group I, II, and III base stocks are each derived from crude oil via extensive processing, such as fractionating, solvent extraction, solvent dewaxing, and hydroisomerization. Group III base stocks can also be produced from synthetic hydrocarbons obtained from natural gas, coal, or other fossil resources. Group IV base stocks include polyalphaolefins (“PAOs”) that are produced by the oligomerization of alpha olefins. Group V base stocks include all base stocks that do not belong to Groups I-IV, such as naphthenics, polyalkylene glycols (“PAG”), and esters.

[0098] Additionally, there are the informal categories of base stocks referred to as “Group II+” and “Group 111+” that are generally recognized within the lubricant industry as corresponding to base stocks that exceed the minimum classification requirements of the formal group. For example, a“Group II+” base stock can have a viscosity index (VI) above 110 and a “Group III+” base stock can have a viscosity index (VI) between 130 and 150. Group III+ base stocks have properties tailored specifically to application. In addition to viscosity index, control of properties such as CCS (Cold Crank Simulator by ASTM D5293-20) and Noack (ASTM D5800-18).Table 3American Petroleum Institute Classifications of Group I - Group V

[0099] Aromatic content of base stocks, paraffinic diesel and wax is measured by various methods including chromatography and ultraviolet spectroscopy, such as those described in US Publication No. 2013 / 0179092, published July 11, 2013, which is incorporated herein by reference. Additionally, techniques such as mass spectroscopy and NMR spectroscopy is used to establish detailed composition of a crude oil. The empirical n-d-M method (ASTM D3238-17) is also available for determining carbon type (paraffinic carbon, naphthenic carbon, and aromatic carbon) distributions in a sample oil by relatively simple measurements of physical parameters, such as refractive index (n), density (d) and molecular weight (M).

[0100] Described herein are processes for producing a base stock. According to an embodiment, hydrocarbons produced by the present methods comprise less than 0.03 wt.% sulfur, a Pour Point of less than -60 °C, a Noack volatility of less than 30 wt.% and a CCS value at -35 °C of less than 600 cP by ASTM D5293. The base stocks produced according to the present disclosure have a KV100 in about 2.7 cSt to about 3.5 cSt.

[0101] As described herein, the base stock produced by the present processes have a kinematic viscosity at 100 °C. (“KV100”), measured according to ASTM standard D-445, from about 3.5 cSt to about 2.7 cSt, about 3.4 cSt to about 2.8 cSt, or about 3.3 cSt to about 2.9 cSt. In various embodiments of the invention, the base stocks have a kinematic viscosity at 40 °C. (“KV40”), measured according to ASTM standard D-445, from about 12 cSt to about 15 cSt, from about 11 cSt to about 14 cSt, or from about 12 cSt to about 13 cSt. The base stock or base stock blend may have a viscosity index, calculated according to ASTM standard D-2270, greater than about 100, about 105, about 110, about 115.

[0102] The base stocks have a NOACK volatility of no less than about 30%, preferably no less than about 25%. According to various embodiments of the invention, the base stocks have a Noack volatility of between about 30.0 wt.% to about 20.0 wt.% or about 21.0 wt.% to about 24.0 wt.%. As used herein, Noack volatility is determined by ASTM D-5800.

[0103] Additionally, or alternatively, the base stocks have a pour point of less than about -60 °C., less than about -63 °C., less than about -64 °C., less than about -70 °C according to various embodiments of the present invention. According to various embodiments of the invention, the base stocks have a pour point of between about -70 °C. and -60 °C. In an embodiment further, the base stocks have a flash point of greater than 200 °C.EXAMPLES

[0104] The features of the disclosure are described in the following non-limiting examples.Example 1Screening of ZSM-57, ZSM-23, MCM-49 and 14PW Catalyst for C14 LAO dimerization

[0105] In order to demonstrate the superior activity and selectivity of MCM-49 versus other solid acid catalysts (e.g. , ZSM-57, ZSM-23 and HPW), 2 g (two grams) of a solid acid catalyst was crushed and sieved down to between about 300 micrometer and about 600 micrometers. The crushed solid acid catalyst was then loaded in SiC (50 % / 50 % blend) and a Ci4 LAO feedstock was contacted with the solid acid catalyst. C14 LAO feedstock was not dried before testing. Testing was performed at 120 °C, 160 °C and 200 °C at 5 barg backpressure in liquid phase condition and with a weight-hourly space velocity (WHSV) of 3 h'1and 1.5 h'1in an upflow reactor configuration.

[0106] As shown in FIG. 1A, IB, 1C and ID, the MWW framework type MCM-49 catalyst showed remarkable activity and selectivity in producing dimer versus the other oligomerization catalysts, such as ZSM-57 and ZSM-23. The data also shows superior performance in comparison to a supported heteropoly acid (HPW) type catalyst.

[0107] FIG. 1A, IB, 1C and ID are charts of observed selectivity to produce linear and / or branched hydrocarbons of these four different solid acid catalysts (excluding CM isomerization selectivity) and also shows total Ci4 conversion of each solid acid catalyst at the three different process temperatures and two different feedstock flow rates that were measured in weight-hourly space velocity.

[0108] Table 3 below provides the properties of the solid acid catalyst used in this Example 1.Table 3

[0109] FIG. 2 further summarizes solid acid catalyst testing of Ci4 LAO dimerization. In FIG. 2, the reported conversion, selectivity, and yield is an average of about 10 hours at the condition where the solid acid catalyst showed the highest overall dimer yield. An active phase is the catalytically active component of the catalyst.

[0110] The observed high activity and selectivity for MCM-49 appears to be due to the high acid site density and accessibility (external pockets) of the MWW framework. Accessibility and high acid site density leads to high activity at moderate temperature (160 °C), which further results in less cracking, (skeletal) isomerization and coking side reactions.Example 2 Sample Production Run with MCM-49

[0111] A sample production run, targeting approximately 500 mL of a C14 dimer heart-cut for application testing and benchmarking to Group II / III / III+ base stocks was performed using the selfbound MCM-49 catalyst identified in Example 1, solid acid catalyst screening and Ci4 LAO feedstock.

[0112] Two grams (2 g) of MCM-49 catalyst (crushed and sieved down to 300 -600 micrometer) was loaded in SiC (50 % - 50 % blend). Ci4 LAO feedstock was not pre-dried before the run. Start of run conditions were WHSV = 3 h-1 and 160 °C. The system was kept at 5 barg backpressure (fully liquid phase conditions) in an upflow reactor configuration.

[0113] FIG. 3 provides a summary of the sample production run and shows conversion and selectivity profile for Ci4 < dimer sample run with MCM-49. The Ci4 LAO conversion at start of run conditions (WHSV = 3 h-1 and 160 °C) was 65 wt.% and selectivity to dimer was around 65 wt.% with about 30 wt.% selectivity to Ci4 olefin isomers and the remainder to cracked (< C14), lightly cracked (Cl 5 - C24) and (>C29) heavy products. The apparent deactivation rate increased to an average of 1.8 x IO-6mol Ci4+ dimer h1g feed1versus an initial catalyst activity of 2.8 x 10-3mol Ci4+ dimer h-1g catalyst-1. From this, we can estimate that at constant run conditions, 1 T of catalystwould “completely” deactivate after exposure to approximately 1600 T of feed, or, in other words, expected ultimate catalyst life would be 1600 Tfeed / Tcataiyst.

[0114] After approximately 350 hours on stream, 1500 grams of reactor effluent was collected (ultimate catalyst life: 226 gci4+ dimer / gcataiyst and 1500 gfeed / gcataiyst) and the run was terminated.

[0115] Reactor product distillation was carried on an Iludest DN50 laboratory vacuum batch distillation set up. A six liter (6 L) round-bottom flask vessel was used for distillation of the total reactor effluent, which was combined with a high boiling bottom fraction of Primol 542 (~C36 average carbon number, containing < 0.5 wt.% C14+ dimer).

[0116] FIG. 4 is a summary of the compositions (bars, left axis) and weights (black squares, right axis) of the feedstock, the collected fractions and a final heart-cut obtained from distillation of the Ci4+ LAO dimer of the total reactor effluent. FIG. 5 are reconstructed distillation curves of the process described herein including (open circles) the added Primol 542 bottoms and excluding (closed circles) the added Primol 542 bottoms.Example 3 Hydrogenation of the Heart-Cut Fraction

[0117] As shown in FIG. 4, Fractions 7 through Fraction 16 (380 °C to 415 °C) were selected as the heart-cut for subsequent hydrogenation. Hydrogenation was performed over 2 g massive Ni catalysts (Ni3298, BASF). An initial hydrogenation experiment was run at LHSV 10 h'1and 100 °C at 16 barg pressure and H2 to olefin+n ratio of 2, assuming an average olefin molar weight of 392 g mol'1(C28H56). However, bromine testing after hydrogenation showed a rather high value of 8285 mg bromine / 100 gsampie, suggesting that a significant amount of olefins was left unhydrogenated. Therefore, a second hydrogenation was carried out at a LHSV of 1 h'1and 150 °C and H2 to olefin molar ratio of 2. Bromine testing after hydrogenation showed a low bromine index value of 236 mg bromine / 100 gsampie.

[0118] The heart-cut (C14+ LAO dimer) produced had properties of a Group 11+ base stock and / or Group III base stock. However, the hydrogenated oligomers (a plurality of synthetic hydrocarbons) had a narrower carbon number distribution and a narrower branching distribution compared with that of the reported distributions for Group II / III base stock. Lee, S. et al. Chemical Composition of Group II Lubricant Oil Studied by High-Resolution Gas Chromatography and Comprehensive Two- Dimensional Gas Chromatography. Energy Fuels 2007, 21, 6, 3477-3483, incorporated by reference. Skeletal isomerization of the dimer produced influences the properties of the synthetic hydrocarbons. For example, the extent of branching of the hydrocarbon depends on the process conditions, includingan average run temperature and the catalyst.

[0119] Properties of the hydrogenated C14+ LAO dimer produced are shown in Table 4 below. Also, in Table 4, the C14 LAO dimer properties are compared to reported Group III base stock, GTL 3 (Fischer-Tropsch technology) and Group 11+ base stock, YubaseTM 3 base stock. In addition, the properties of the C14+LAO dimer produced are compared with that of the Chevron 100R, a Group II base stock, and the SpectraSyn™ 3.5 Max, a Group IV base stock.

[0120] As shown, the viscosity index was slightly lower versus that of any of the base stocks, while flash point properties (Cleveland Open Cup (“COC”)) were practically identical between the experimental sample and each base stock. Cold-Crank Simulator (“CCS”) results, although not tested at identical temperature, were slightly favorable in comparison to the GTL 3 base stock, while the pour point and Noack volatility performance was superior for the hydrogenated C14 LAO dimer sample versus the Group 11+ and Group III base stocks.

[0121] Compared to a typical 4 cP Group II base stock reference, Chevron 100R, the C14 LAO dimer showed higher performance in most properties, including cold crank simulator tests, pour point and Noack volatility. The viscosity index and flashpoint of the experimental sample were similar versus the slightly higher viscosity Chevron 100R reference.Table 4

[0122] Overall, even compared to the slightly higher viscosity Group IV Base Stock, SpectrasynTM 3.5 MaX, the properties of the synthetic hydrocarbons produced were comparable in terms of performance. The resulting Ci4+ LAO hydrogenated oligomers show that the present processes described herein provide a lower cost Group II+ / III base stock production route (process) - even when the solid acid catalyst and process conditions for the sample production run were not optimized. Process and solid acid catalyst tuning and permutations with mixed Ci4, Ci6 and Cis LAO feedstocks can allow for tuning the viscosity and other product properties for specific applications.Additional Embodiments

[0123] Additionally, or alternately, the invention relates to:

[0124] Embodiment 1. A process for producing a base stock comprising the steps of: providing a LAO feedstock comprising a C14+ LAO; contacting the LAO feedstock with a solid acid catalyst to produce an oligomerizationmixture comprising a Cl 4+ LAO dimer and a monomer, wherein the solid acid catalyst is a MWW framework type catalyst; separating the Cl 4+ LAO dimer from the monomer in the oligomerization mixture in a distillation process; and hydrogenating the C14+ LAO dimer to produce a base stock having a viscosity between 2.7 and 3.5 KV100 and 12 cSt and 15 cSt KV40 as measured by ASLM test method D445 and a viscosity index greater than 100 as measured by ASTM test method D2270.

[0125] Embodiment 2. The process for producing a base stock of embodiment 1, wherein the oligomerization mixture is not cooled prior to the step of separating the dimer from the monomer.

[0126] Embodiment 3. The process for producing a base stock of embodiment 1, wherein the monomer is recycled and provided as the feedstock.

[0127] Embodiment 4. The process for producing a base stock of embodiment 1, wherein the MWW framework catalyst is not separated from oligomerization mixture prior to hydrogenating the Cl 4+ LAO dimer.

[0128] Embodiment 5. The process for producing a base stock of embodiment 1, further comprising a second distillation of the hydrogenated oligomerization mixture.

[0129] Embodiment 6. The process for producing abase stock of embodiment 1, wherein between45 wt. % and 80 wt. % of the C14+ LAO is converted to the C14+ LAO dimer.

[0130] Embodiment 7. The process for producing a base stock of embodiment 1, wherein the base stock comprises greater than 80 % of branched synthetic hydrocarbons produced.

[0131] Embodiment 8. A process for producing a plurality of synthetic hydrocarbons comprising the steps of: providing a LAO feedstock comprising a LAO and mixtures thereof, wherein the LAO has a carbon number of 10 and greater; and contacting the LAO feedstock with a solid acid catalyst to produce an oligomerization mixture comprising at least one dimer of the LAO and a monomer, wherein the LAO is in a liquid phase and the solid acid catalyst is an MWW-type zeolite; separating the LAO dimer from the monomer, and hydrogenating the dimer of the LAO to produce the plurality of synthetic hydrocarbons having a viscosity between 2.7 and 3.5 KV100 and 12 cSt and 15 cSt KV40 as measured by ASTM test method D445 and a viscosity index greater than 100 as measured by ASTM test method D2270.

[0132] Embodiment 9. The process of embodiments 1 or 8, wherein the base stock has a KV 100between 2.7 and 3.25, KV40 between 12 and 14, and a viscosity index between 100 and 115.

[0133] Embodiment 10. The process of embodiments 1 or 8, wherein the oligomerization mixture comprises between 30 wt.% and 90 wt.% dimer of the LAO.

[0134] Embodiment 11. The process of embodiments 1 or 8, wherein the catalyst is MCM-49.

[0135] Embodiment 12. The process of embodiments 1 or 8, wherein the catalyst Si / AL ratio is between 10 and 50.

[0136] Embodiment 13. The process of embodiments 1 or 8, wherein the specific surface area of the catalyst is greater than 400 m2 / g.

[0137] Embodiment 14. The process of embodiments 1 or 8, wherein the catalyst collidine uptake is greater than 75 micromoles / gram.

[0138] Embodiment 15. The process of embodiments 1 or 8, wherein the process is performed in an isothermal fixed bed type reactor.

[0139] Embodiment 16. The process of embodiments 1 or 8, wherein the process is operated at a temperature between 120 °C and 200 °C.

[0140] Embodiment 17. The process of embodiments 1 or 8, wherein the process is operated at a WHSV between 1.5 and 3.0 per hour.

[0141] Embodiment 18. The process of embodiments 1 or 8, wherein the solid acid catalyst has a ultimate catalyst life of greater than 1500 Tfeed / Tcatalyst.

[0142] Embodiment 19. A process for producing a hydrogenated oligomer useful as a base stock comprising the steps of providing a LAO feedstock comprising a C14+ LAO; contacting the LAO feedstock with a MCM-49 catalyst to produce an oligomerization mixture comprising a C14+ LAO dimer and a monomer; separating the C14- LAO dimer from the monomer, and hydrogenating the C14+ LAO dimer to produce the hydrogenated oligomer having a viscosity between 2.7 and 3.5 KV100 and 12 cSt and 15 cStKV40 as measured by ASTM test method D445 and a viscosity index greater than 100 as measured by ASTM test method D2270.

[0143] Embodiment 20. The process of embodiments 1, 8 or 19, wherein the base stock has a Noack Volatility of less than 30 wt.% as measured by ASTM test method D5800 and a pour point of less than - 60 °C as measured by ASTM test method D5950.

[0144] Many alterations, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description without departing from the spirit or scope of the present disclosureand that when numerical lower limits and numerical upper limits are listed herein, ranges from any lower limit to any upper limit are contemplated.

Claims

CLAIMS1. A process for producing a base stock comprising the steps of: providing a LAO feedstock comprising a Ci4+ LAO; contacting the LAO feedstock with a solid acid catalyst to produce an oligomerization mixture comprising a C14+ LAO dimer and a monomer, wherein the solid acid catalyst is a MWW framework type catalyst; separating the C14+ LAO dimer from the monomer in the oligomerization mixture in a distillation process; and hydrogenating the C14+ LAO dimer to produce a base stock having a viscosity between 2.7 and 3.5 KV100 and 12 cSt and 15 cSt KV40 as measured by ASTM test method D445 and a viscosity index greater than 100 as measured by ASTM test method D2270.

2. The process for producing a base stock of claim 1, wherein the oligomerization mixture is not cooled prior to the step of separating the dimer from the monomer.

3. The process for producing a base stock of claim 1, wherein the monomer is recycled and provided as the feedstock.

4. The process for producing a base stock of claim 1, wherein the MWW framework catalyst is not separated from oligomerization mixture prior to hydrogenating the C14+ LAO dimer.

5. The process for producing a base stock of claim 1, further comprising a second distillation of the hydrogenated oligomerization mixture.

6. The process for producing a base stock of claim 1, wherein between 45 wt. % and 80 wt. % of the C14+ LAO is converted to the C14+LAO dimer.

7. The process for producing a base stock of claim 1, wherein the base stock comprises greater than 80 wt. % of C14+ LAO dimer.

8. A process for producing a plurality of synthetic hydrocarbons comprising the steps of: providing a LAO feedstock comprising a LAO and mixtures thereof, wherein the LAO has acarbon number of 10 and greater; contacting the LAO feedstock with a solid acid catalyst to produce an oligomerization mixture comprising at least one dimer of the LAO and a monomer, wherein the LAO is in a liquid phase and the solid acid catalyst is an MWW-type zeolite; separating the LAO dimer from the monomer, and hydrogenating the dimer of the LAO to produce the plurality of synthetic hydrocarbons having a viscosity between 2.7 and 3.5 KV100 and 12 cSt and 15 cSt KV40 as measured by ASTM test method D445 and a viscosity index greater than 100 as measured by ASTM test method D2270.

9. The process of claims 1 or 8, wherein the base stock has a KV 100 between 2.7 and 3.25, KV40 between 12 and 14, and a viscosity index between 100 and 115.

10. The process of claims 1 or 8, wherein the oligomerization mixture comprises between 30 wt.% and 90 wt.% dimer of the LAO.

11. The process of claims 1 or 8, wherein the catalyst is MCM-49.

12. The process of claims 1 or 8, wherein the catalyst Si / Ak ratio is between 10 and 50.

13. The process of claims 1 or 8, wherein the specific surface area of the catalyst is greater than400 m2 / g.

14. The process of claims 1 or 8, wherein the catalyst collidine uptake is greater than 75 micromoles / gram.

15. The process of claims 1 or 8, wherein the process is performed in an isothermal fixed bed type reactor.

16. The process of claims 1 or 8, wherein the process is operated at a temperature between 120 °C and 200 °C.

17. The process of claims 1 or 8, wherein the process is operated at a WHSV between 1.5 and3.0 per hour.

18. The process of claims 1 or 8, wherein the solid acid catalyst has a ultimate catalyst life of greater than 1500 Tfeed / TCataiyst.

19. A process for producing a hydrogenated oligomer useful as a base stock comprising the steps of: providing a LAO feedstock comprising a C14+ LAO; and contacting the LAO feedstock with a MCM-49 catalyst to produce an oligomerization mixture comprising a C14+ LAO dimer and a monomer; separating the C14+ LAO dimer from the monomer, and hydrogenating the C14+ LAO dimer to produce the hydrogenated oligomer having a viscosity between 2.7 and 3.5 KV100 and 12 cSt and 15 cSt KV40 as measured by ASTM test method D445 and a viscosity index greater than 100 as measured by ASTM test method D2270.

20. The process of claims 1, 8 or 19, wherein the base stock has a Noack Volatility of less than 30 wt.% as measured by ASTM test method D5800 and a pour point of less than - 60 °C as measured by ASTM test method D5950.

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