CA1325020C - Olefinic oligomers having lubricating properties and process of making such oligomers - Google Patents

Abstract

OLEFINIC OLIGOMERS HAVING LUBRICATING PROPERTIES
AND PROCESS OF MAKING SUCH OLIGOMERS

ABSTRACT

Novel lubricant compositions comprising polyalpha-olefins are disclosed having high viscosity indices with low pour point.
The compositions are characterized by a uniform molecular structure with low branch ratios. The invention describes a liquid lubricant composition comprising C30-C1300 hydrocarbons, said composition having a branch ratio of less than 0.19, weight average molecular weight between 300 and 45,000, number average molecular weight between 300 and 18,000, molecular weight distribution between 1 and 5 and pour point below -15°C. 1-decene trimer comprising 9-methyl, 11-octylheneicosane and 11-octyldocosane is disclosed. The lubricant compositions are produced by contacting said alpha olefin with a supported solid reduced group VIB (e.g., chromium) catalyst under oligomerizaeion conditions at a temperature of about 90 to 250°C to produce liquid lubricant hydrocarbon. The hydrogenated lubricant range hydrocarbon product has a viscosity index of about 130 to 280 and a viscosity up to about 750 mm2/s(cs). The process is particularly useful where the starting alpha olefin consists essentially of olefinic hydrocarbons having 8 to 14 carbon atoms or mixtures thereof, wherein the process conditions include a reaction temperature of about 100 to 180°C; and wherein the support catalyst includes porous inert silica.

Description

OL~FINIC OLIGOMEI?S ~VING LUBRICATING PROPERTIES
AND PROCESS OF MA~ING SUCH OLIGCM~S

This invention relates to novel lubricant compositions and more particularly, to novel synthetic lubricant compositions prepared from alpha-olefins, or l-alkenes. The invention -specifically relates to novel synthetic lubricant compositions froml-alkenes exhibiting superior viscosity indices and other improved characteristics essential to useful lubricating oils. This invention further relates to a process for manufacturing such lubricant compositions.
Efforts to improve upon the performance of natural lo mineral oil based lubricants by the synthesis of oligomeric hydrocarbon fluids have been the subject of important research and development in the petroleum industry for at least fifty years and have led to the relatively recent market introduction of a number of superior polyalpha-olefin (PAO) synthetic lubricants, primarily 1S based on the oligomerization of alpha-olefins or l-alkenes. In terms of lubricant property improvement, the thrust of the industrial research effort on synthetic lubricants has been toward fluids exhibiting useful viscosities over a wide range of temperature, :
i.e., improved viscosity index (Vl), while also showing lubricity, ~o thermal and oxidative stability and pour point equal to or better than mineral oil. These new synthetic lubricants lower friction and hence increase mechanical efficiency across the full spectrum of mechanical loads from worm gears to traction drives and do so over a wider range of operating conditions than mineral oil lubricants.

2, The chemical focus of the research effort in synthetic lubricants has been on the polymerization of l-alkenes. Well known -structure/property relationships for high polymers as contained in the various disciplines of polymer chemistry have pointed the way to l-alkenes as a fruitful field of investigation for the synthesis of oligomers with the structure thought to be needed to confer improved ~ ' ~ .

F-4862(~872) - 2-- 1 325020 l~bricant properties thereon. Due largely to studies on the ~olymerization of ?ropene ~nd vinyl monamers, the mechanism of the polymerization of 1-alkenes and the effect ofthat mechaIism on polymer structure is reasQn~bly well understood, providing a strong resource for targeting on potentially useful oligomerizaticn me~hods and oligomer s~r~tures. Buildir.~ on that resource, in the prior : art oligomers of 1-al~nes from C6 to C20 have been prepared with commercially useful synthetic lubricants from l-decene : -oligomerization yielding a distinctly superior lubricant product via 1~ either cationic or Zie~ler catalyzed polymerization.
Theore~ically, the oligomerization of l-decene, ~or example, to lubricanl oligomers in the C30 and C40 ran~e can res~lt in a very large number of structural isomers. Henze and Blair,J.A.C.S. 54,153B, calculate over 6~ X10l2 isomers for C30-C40. Disc~vering exactty those isomers, and the associated oligomerization process, that produce a preferred and superior synthetic lubricant meeting the specification requirements of wide-temperature fluidity while maintaining low pour point rep~esents a prodigious challenge to the workers in the field.
Brennan, Ind. Eng. Chem. Prod. Res. Dev. 1980, 19, 2-6, ci~es l-decene trimer as an example of a structu~e compatible with s~ruc~ures associated wi~h superior low temperature ~luidity wherein the concentration of atoms is very clcse to the center of a chain of carbon atoms. Also doscribed therein is the apparent dependency : -of properties of the oligomer on the oligo~orization process, i.e., cationic polymerization or Ziegler-type catalyst, known and prac ti ced in the art.
One characteristic of the molecular structure of l-alkene oligomers ~hat has been found to correlate very well with improved lubricant properties in commercial eynthetic lubricants is the ratio of methyl to methylene groups in the oligomer. The ratio is called the branch ratio and is caloulatet from infra red data as discussed in "Standard ~ydrocarbons of High Molecular Weight", AnalYtical ~:7 . . ' 1325~
F-4862(4872) --3--Chemistrv, Vol.25, no.l0, p.l466 (1953). Viscosity index has been found to increase with lower branch ratio. Heretofore, oligomeric liquid lubricants exhibiting very low branch ratios have not been synthesi~ed from l-alkenes. For instance, oligomers prepared from l-decene by either cationic polymerization or Ziegler catalyst polymerization have branch ratios of greater than 0.20. Shubkin, Ind. Eng.Chem. Prod. Res Dev. 1980, 19, 15-19, provides an explanation for the apparently limiting value for branch ratio based on a cationic polymerization reaction mechanism involvin~
rearrangement to produce branching. Other explanations suggest isomerization of the olefinic group in the one position to produce an internal olefin as the cause for branching. Whether by ~earrangement, isomerization or a yet to be elucidated mechanism it is clear that in the art of l-alkene oligomerization to produce 1~ synthetic lubricants as practiced to-date excessive branching occurs and constrains the limits of achievable lubricant properties, particularly with respect to viscosity index. Obviously, increased branching increases the number of isomers in the oligomer mixture, orienting the composition away from the structure which ~ould be ~o preferred from a consideration of the theoretical concepts discussed above.
U.S. Patent 4,282,392 to Cupples et al. discloses an alpha-olefin oligomer synthetic lubricant having an improved viscosity-volatility relationship and containing a high proportion of tetramer and pentamer via a hydrogenation process that effects skeletal rearrangement and isomeric composition. The composition claimed is a trimer to tetramer ratio no higher than one to one.
The branch ratio is not disclosed.
A process using coordination catalysts to prepare -high polymers from l-alkenes, especially chromium catalyst on a - silica support, is described by Weiss et al. in Jour. Catalysis 88, 424-430 (1984) and in Offen. DE 3,427,319. The process and products --therefrom are discussed in more detail hereinafter in comparison ~ith the process and products of the instant invention.
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It is well known that Lewis acids such as promoted BF3 and/or metal halides can catalyze Friedel-Crafts type reactions. However, olefin oligomers and more particularly PAO oligomers have been produced by methods in which double bond isomerization of the starting 1-olefin occurs easily. As a result, the olefin oligomers have more short side branches. These side branches degrade ;
their lubricating properties.
Liquid hydrocarbon lubricant compositions have been obtained from C6-C20 l-alkene oligomerization that exhibit surprisingly high viscosity index (VI) while, equally surprisingly, exhibit very low pour points. The compositions comprise C30-C,300 hydrocarbons, the compositions having a branch ratio of less than 0.19; a weight average molecular weight bet~,veen 300 and 45,000; a number average molecular weight between 300 and 18,000; a molecular weight distribution between 1 and 5; and pour point below -15C.
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Further, a novel composition has been discovered comprising 11-octyldocosane having the structure H
c~3 ( cH2 ) ~OC ( CH2 ) gCH3 The foregoing composition has been found to exhibit superior lubricant -~
properties either alone or in a mixture with 9-methyl,11-octylheneicosane.
8urprisingly, the mixture has a viscosity index of greater than 130, preferably from 130 to 280, while maintaining a pour point less than -15C. These -compositions are representative of the instant invention comprising C30H62 alkanes having a branch ratio, or CH3/CH2 ratio, of less than 0.19, preferably 0.10 to 0.16. These low branch ratios and pour points characterize the compositions of the invention.
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F-4862~4872) -~5-- :

referred to herein as polyalpha-olefin or HVq-PA0, con~erring upon the compositions especially ~igh viscosity indices in comparison to commercially available polyalpha-olefin (PA0) synthetic lubricantS.
Unique lubricant oligo~ers of the instant invention can a~o S be made in a wide range of molecular weights and viscosities comprlsing C30 to C1000 hydroca~bons having a branch ratio of less than 0.19 and molecular weight distribution of about l,OS to 2.5. The oligomers can be mixed with conventlonal mineral oils or greases of other properties to provide co~positions also possessing !O outstanding lu~rican~ p~operties. : .
Compositions of the present invention can be prepared by the oligomerization of alpha-olefins such as l-decene under oligomerization conditions in contact with a supported and reduced ~ -valence state metal oxide catalyst r~m Gro~p VIB o~ the IUPAC
l; Periodic Table. Chromium oxide is the preferred metal oxide. ~ .
The present invention provides a process or produc~ng liquid oligomers of olefins, such as l-decene, with branch ratio~ .
below 0.19 and having higher viscosity indices than oligomers with higher ~ranch ra~ios. These oligo~ers with low branch ratios can be u~ed as basestocks for many lubricants or greases with an improved viscosity-temperature relationship, oxidative stab~lity, volatility, etc. They can also be used to improvo vi~cositles and viscosity in~ices of lower quality oils. The olefins can, for example, be - oligomerized over a suppor~ed and reduced metal oxide c~talyst from -Group VIB of the Periodic Table to give oligomers sui~ahle for lubricant application. More partiallarly, the presentinvention is directed to a process for the oligomerizati~ of olefinic hydrocarbons ccn~aLning 6 to 20 ~a~bon ato~s whdch comprises oligomerizing said hydrocarbal under o~igo~erizaticn ~onditions, - 30 wherein the reaction product ccnsists essentially of su~stantially non-iscmerized olefins, for example, alpha olefins such as l-decene, and ~herein a rEljor proporticn of the double bonds of the olefins or ol~inic hydrocarbons are not isomerized, in tho presence : -9 `

I ~ ,', F-4862( 487~ ) --6--of a suitable catalys~, e.g., a supported and rcducod me~al oxide catal)rst from Group VIB of t}~ Perlodic Table.
Tl~e use of reduced Gro~p VIB chro~iura-containing metal oxide on arl inert support oligomerizes liquld olefins which are suitable for use as good quality lube oils is a.novel technique. :

Brief Description of the Drawings ~igure 1 is a comparisal of PAO and HYI~PAO syntheses.
Pigure 2 compares VI for PAO and HVI-PAO ;~
Figure 3 shows pour pointS or PA0 and HVI-PA0 Fi~ure 4 sha~s C-13 NMR spectra for HVI-PAO from l-hex~ne.
~0 Figure 5 shows C-13 N~lR spectra of 5CS ~VI-PAO from 1 -decene .
Figure 6 shows C-13 NMR spectra of 50cs HVI-PA0 from 1 -de cene .
Figure 7 shows C-13 ~MR spectra of 145cs HVI-PA0 from 1 -de cene .
Figure 8 shows the gas chromatograph of HVI-PA0 l-de~ene trimer.
Fi~ure 9 shows C-13 NMR of ~.VI-PAO trimer of l-decene.
Figure 10 shaws C-13 I~R calculatod vS. observed chemical shifts for ~IVI~PAO l-deoone trimer co~ ents.
Detailed Desc~Qtion of the ~ . -In the forlowing descript~ , unle~s otherwise statct, all re~erences to HVI-PA0 oligom~rs or lubricants refer to hydrogenated oligomers and lubricants in keeping with the practice well know.n to those skilled in ehe art of lubricant production. As oligomerized, ~Yq-PA0 oligom~rs are mixtures of d~alkyl vinyled~nic and 1,2 :.
dialkyl or trialkyl mono-olefins. Lower molocular woi~ht -unsa~ura~ed oligomers are preferably hydrogenated to produce eh~rmally and oxidatively stable, useful lubr~cants. Higher molecular weight unsaturated H~q-PA0 oligomers are sufflciently eh~r~a~ly stable to be utilized without hydnogenation and, opticnally, ~ay ~e so employed. ioth unsaturated and hytrogenatet HVI-PA0 of lower or hi8her ~olecular exhibit viscosity indi oes of at ~:~
least 130, preferably from 130 to ~80, and pour poin~ below -15C, preferably ~45C.
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F-4862( 4872) --7--Referring to Figure 1, the novel oligomers of the invention, or high viscosity index polyalphaolefins (HVI-PA0) are described in an illustration comparin~ the~ with conventional ~:.
polyalphaol0~ins (PA0) from l-decene. Polymeri~ation wi~h the novel reduced c~1romium catalyst described hereinafter leads to an oligo~er substan~ially free of double bond isomeri~ation. C~nventional PA~, on t~e other hand, promoted by B~3 or AlC13 foIms a carbonium ion which,in turn, promotes isomerization of the ole~inic bond and the for~ation of ~ultiple isomers. The HVI-PA0 produced in the present ` :
invention hss a stn~cture with a GH3/C~I2 ratioC0.19 compared ~o a ratio of ~O.Z0 for PA0.
Figure 2 compares the vis¢osity index versus viscosity relationship for ~VI-PAO and PAO lubricants, showing that HVI-PA0 is distinctly superior to PA0 at all viscosities tested.
1~ Remar~ably, despite the more regular structure of the HVI-P~0 o~igomers as shown by branch ratio that results in improved vis~oSity index ~VI), they sh~w pour points superior to PAO.
Conceivably, oligomers of regular structure containing fewer isomers would be expected to have higher solidification temperatures and ~ -~o higher pour points, reducin~ their utility as lubricants. But, : ~ .
surprisingly, such is not the case for HVI-PA0 o the present inventioM~ Figure 2 and 3 illustrate superiority o ~tI-PAO in terms of both pour point and VI.
It has been found that the process described ~erein to -: :~
~s produce the novel HVI-PA0 oligomers can be controlled to yield ~:
oligomers having weight average molecular weight between 300 and ::
45>00~ and number avera~e molecular weight between 300 and 18,000.
Measured in carbon numbers, molecular weights range from C3 to C130~ and viscosity up tO 15~ mm~/s(cs) a~ 100C, with a preferred r~nge o C30 to C10OO and a viscosity o~ up to ;00 ~ :
mm2/s~cs) at 100C, preferab~y between 3 and 750 mmZ/s.
~olecular weight distributions ~.~WD), defined as the ratio of weight average molecular weight to numb~r aYerage molecular weight, range from 1~00 to 5, with a preferred range of 1.01 to ~ and a more -~

F-4862(4872) --8--preferred MWD of about 1.05 to 2.5. Compared to conventional PA0 derived from BF3 or AlC13 catalyzed polymerization of l-alkene7 HVI-PA0 of the present invention has been found to have a higher proportion of higher molecular weight polymer molecules in the product.
Viscosi~ies of the novel HVI-PAO oligomers measured at 100C range from 3 mm2s(cs) to S000 mm2/s(cs). The viscosity index for the new polyalpha-olefins is approximately described by the following equation:
VI =129.g + 4.58 x (V100C)0 5~ where V10O C is kinematic viscosity in centistokes measured at 100C.
The novel oligomer compositions disclosed herein have been examined to define their unique structure beyond the important characteristics of branch ratio and molecular weight already noted.
Dimer and trimer fractions have been separated by distillation and components thereof further separated by gas chromatography. These lower oligomers and components along with complete reaction mixtures of HVI-PA0 oligomers have been studied using infra-red spectroscopy -~
and C-13 NMR. The studies have confirmed the highly uniform - -structural composition of the products of the invention, particularly when compared to conventional polyalphaolefins produced by BF3, AlC13 or Ziegler-type catalysis. The unique capability of C -13 NMR to identify structural isomers has led to the identification of distinctive compounds in lower oligomeric fractions and served to confirm the more uniform isomeric mix present in higher molecular weight oligomers compatible with the finding of low branch ratios and superior viscosity indices.
l-hexene HVI-PAO oligomers of the present invention have been shown to have a very uniform linear C4 branch and contain 33 regular head-to-tail connections. In addition to the structures from the regular head-to-tail connections, the backbone structures have some head-to-head connection, indicative of the following structure as confirmed by NMR:

g~z(4872) 9 H( ~ CH2-) ,C- (-CH2- 1 - ) ~,H . , , C~)3 ~CH2)3 The I~MR poly(l-hexene3 spectra are shown Ln ~igure 4.
The oligomeri2a~icn o~ l-decene by reduced ~rale~ce s~ate, supported chromium also yields a HV~-PAO with a structure analogous to that of l-hexene oligome~. The lubricant products after distillaticn tO remove light fractions and hydrogenation have chara~teristic C-13 IYM~ spectra- Figures 5, 6 and 7 are the C-13 1~ .~R spectra of typical HVI-PAO lube produc~s with viscosities of S :: . mm2/s(cs), 50 mm2/s(cs~ and 14S mm2/s(cs) at 10~C.
In the following tables, Table A presents the I~MR data for Figure 5, Table B presents the ~R data for Figure 6 and Table C ::~
presen~s ~he ~MR data for Figure 7. ~`
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F -4862 (4872) - - 10 --Table A (Fig. 5) Point Shift(ppm)Intensity Width(Hz) 1 79.096138841. 2.74 2 74.855130653. 4.52 3 42.394148620. 6.68 4 40.639133441. 37.6 ~0.298163678. 32.4 6 40.054176339. 31.2 l~ 7 39.420134904. 37.4 8 37.714445452. 7.38 9 37.373227254. 157 37.081145467. 186 11 36.788153096. 184 1, 12 36.593145681. 186 13 36.447132292. 189 14 36.057152778. 184 35.619206141. 184 16 35.082505413. 26.8 17 34.351741424. 14.3 18 34.0591265077. 7.65 19 32.2075351568. 1.48 30.4033563751. 4.34 21 29.9658294773. Z.56 ~, 22 29.6234714955. 3.67 -23 28.35636g728. 10.4 24 28.16130587~ . 13.2 26.9911481260. 4.88 26 22.8974548162. 1.76 27 20.265227694. 1.99 28 14.2214592991. 1.62 F-4862(4872) --11--Table B(Fig. 6) No.Freq(Hz) PPM Int%
11198.98 79.147 1856 21157.95 77.004 1040 31126.46 74.910 1025 4 559.57 37.211 491 5 526.61 35.019 805 ' 6 514.89 34.240 1298 7 509.76 33.899 1140 8 491.45 32.681 897 9 482.66 32.097 9279 10456.29 30.344 4972 11488.24 29.808 9711 12444.58 29.564 7463 13426.26 28.347 1025 14401.36 26.691 1690 -15342.77 2~.794 9782 16212.40 14.124 8634 -17 0.00 0.000 315 '~0 '''.
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F-4862(4872) --12--Table C (Fig.7) Point Shift(ppm)Intensity Width(l~z) 1 76.903627426. 2.92 2 40.811901505. 22.8 ; 3 40.568865686. 23.1 4 40.324823178. 19.5 37.158677621. 183.
6 36.915705894. 181.
7 36.720669037. 183.
lo 8 36.428691870. 183.
9 36.233696323. 181.
35.2591315574. 155.
11 35.0151471226. 152.
12 34.3331901096. 121.
13 32.7261990364. 120.
14 32.14120319110. 2.81 31.3621661594. 148.
16 30.3889516199. 19.6 17 29.90117778892. 9.64 18 29.60918706236. 9.17 19 28.3911869681. 122.
27.5141117864. 173.
21 26.7352954012. 14.0 22 22.83920895526. 2.17 ^i5 23 14.16916670130. 2.06 ,:
In general, the novel oligomers have the following regular head-to-tail structure where n can be 3 to 17: --- (CH2-CH)X-(CH2)n 132502~ :~
F-4862( 4872) --13--with s~ne head-to-head cannections.
The trimer of l-decene HVI-PA0 oligomer is separated ~rom the oligomerizatian mi~ure by distillation rom a 20 mm2/s(cs) as-synthesized HVl-PA0 in a short-path apparatus in the range o -~
165-210~C at 13.3-26.6 Pa (0.1-0.2 torr). Tbe unhydrogenated trimer exhibited ~he ~ollowing YiSCOmetriC properties;
~ ~ 40C - 14.88 mm2/s(cs): V @ 100C =3.67 mm2/s(cs); VI = 137 The trimer is hydrogena~ed at 235C and 4200 kPa H2 with Ni on kieselguhr hydrogenation catalyst tO give a hytrogenated 1~ HVI~PA~ trimer with the following properties:
V ~ - 40~C - 16.66 mm2/s(cs); Y ~ 100C = 3.91 mm2/s(cs) Vl = 133 ~:
Pour Point = less than -4SC;
Gas chromatographic anàlysis of the trimer reveals that it is composed of essen~ially tW~ c~mponents having retention times of 1~10 seconds and 1878 seconds under the ollowing conditions;
Gas chromatograph (g.c.) column-60 metor capillary column, .: .. `
0.32 mmid (mm inside diameter3, coated with stat~onary pkase SPB-l ~
with ~ilm thickness 0.25mm, available from Supelco chromatographyi - :
supplies, catalog no. 2-4046. ::.:.
Separation Conditions -'Varian Gas ~h~omatog~aph, ~o~el no. ; .
3700, equipped with a flame i~nization detecto~ and capillary : . :
injector port with spli~ ratio o~ about 50 ~2 carrier gas flow rate is Z.5 ml/minute. Injector port temperature 300C; detector :: .:
port tempera~ure 330~C, column temperabure is set initially at 45C: --for 6 mLnutes, programmed heating at 15C/minute to 3~C final ~emperature and holdLng at final t~mperature for 60 minutes. Sample injecti~n size is 1 microliter. Under these conditions, the ......
re~ention ~ime of a g.c. standard, n-dodecane, is 968 seconds. ~.
A typical chromatograph is shown in ~igure 8.
3~ The C-13 NMR spectra, (Figure 9), of the distilled C~
produc~ confirm the chemical structures. Table ~ lis~s C-13 ~MR :.
data for Figure 3.
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1 3~5020 F-4862( 4872) --14--Table D (Fig.(9) PQint Shift(pFm) _Intensity _ Width(Hz) 55.98711080. 2.30 2 42.63213367. 140.
3 42.38816612. 263.
4 37.80740273. 5.90 37.31912257. 16.2 6 36.53911374. 12.1 7 35.41811631. 35.3 8 35.12633099. 3.14 9 34.63839277. 14.6 34.054110899.3. 32 11 33.61512544. 34.9 12 33.46913698. 34.2 13 32.98111278. 5.69 14 32.83513785. 57.4 32.201256181.1.41 16 31.81117867. 24.6 17 31.47013327. 57,4 18 30.398261859.3.36 19 29.959543993.1.89 29.618317314.l. l9 21 28.83811325. 15.1 22 28.35124926. 12.4 23 28.15629663. 6.17 24 27.23044024. 11.7 26.986125437.-0.261 26 22.892271278.1.15 2 7 20.2~017578. -22.1 28 14.167201979.2.01 F-4862(4872) --15--The individual peak assignment of the C-13 spectra are shown in Figure 9. Based on these structures, the calculated chemical shifts, as shown in Figure 10, matched closely with the observed chemical shifts. The calculation of chemical shifts of ~-hydrocarbons is carried out as described is "Carbon-13 NMR for Organic Chemists" by G. C. Levy and G. L. Nelson, 1972, by John Wiley ~ Sons, Inc., Chapter 3, p 38-41. The components were identified as 9-methyl,ll-octylheneicosane and ll-octyldocosane by ~;
infra-red and C-13l~R analysis and were found to be present in a ratio between 1:10 and 10:1 heneicosane to docosane. The hydrogenated l-decene trimer produced by the process of this invention has an index of refraction at 60C of 1.4396.
The process of the present invention produces a surprisingly simpler and useful dimer compared to the di=er produced by l-alkene oligomerization with BF3 or AlC13 as commercially practiced. Typically, in the present invention it has been found that a significant proportion of unhydrogenated dimerized l-alkene has a vinylidenyl structure as follows:
CH2=CRlR2 ~
where Rl and R2 are alkyl groups representing the residue from the head-to-tail addition of l-alkene molecules. For example, l-decene dimer of the invention has been found to contain only three major components, as determined by GC. Based on C13 NMR ;
analysis, the unhydrogenated components were found to be 8-eicosene, ~5 9-eicosene, 2-octyldodecene and 9-methyl-8 or 9-methyl-9-nonadecene.
- The hydrogenated dimer components were found to be n-eicosane and 9-methylnonacosane.
01efins suitable for use as starting material in the invention include those olefins containing from 2 to about 20 carbon atoms such as ethylene, propylene, l-butene, l-pentene, l-hexene, l-octene, l-decene, l-dodecene and l-tetradecene and branched chain isomers such as 4-methyl-1-pentene. Also suitable for use are olefin-containing refinery feedstocks or effluents. However, th~

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1 325(~0 F-4862(4872) --16--olefins used in this invention are preferably alpha olefinic as for example l-heptene to l-hexadecene and more preferably l-octene to -l-tetradecene, or mixtures of such olefins.
Oligomers of alpha-olefins in accordance with the invention have a low branch ratio of less than 0.19 and superior lubricating properties compared to the alpha-olefin oligomers with a high branch ratio, as produced in all known commercial methods.
This new class of alpha-olefin oligomers are prepared by oligomerization reactions in which a major proportion of the double lo bonds of the alphaolefins are not isomerized. These reactions include alpha-olefin oligomerization by supported metal oxide catalysts, such as Cr compounds on silica or other supported IUPAC
Periodic Table Group VIB compounds. The catalyst most preferred is a ~ -lower valence Group VIB metal oxide on an inert support. Preferred , supports include silica, alumina, titania, silica alumina, magnesia and the like. The support material binds the metal oxide catalyst.
Those porous substrates having a pore opening of at least 40 x 10 4 ~m are preferred.
The support material usually has high surface area and large pore volumes with average pore size of 40 to 350 x 10 4~4nn .
The high surface area are beneficial for supporting large amount of highly dispersive, active chromium metal centers and to give maximum efficiency of metal usage, resulting in very high activity catalyst. The support should have large average pore openings of at least 40 x 10 4~m, with an average pore opening of ~ 60 to 300 x 10 4~JL m being preferred. This large pore opening will not impose any diffusional restriction of the reactant and product to and away from the active catalytic metal centers, thus further optimizing the catalyst productivity. Also, for this catalyst to be used in fixed bed or slurry reactor and to be recycled and regenerated many times, a silica support with good physical strength is preferred to prevent cat~lyst particle attrition or disintegration during handling or reaction.
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F-4862(4872) --17--:
The supported metal oxide catalysts are preferably prepared by impregnating metal salts in water or organic solvents onto the support. Any suitable organic solvent known to the art may be used, for example, ethanol,methanol, or acetic acid. The solid catalyst precursor is then dried and calcined at 200 to 900C by air or other oxygen-containing gas. Thereafter the catalyst is reduced by any of several various and well known reducing agents such as, for -example, 00, H2, NH3, H2S, CS2, CH3SCH3, CH3SSCH3,metal alkyl containing compounds such as R3Al, -13 P~3B,R2Mg, RLi, R2Zn, where R is alkyl, alkoxy, aryl and the like. Preferred are CO or H2 or metal alkyl containing compounds. ~-Alternatively, the Group VIB metal may be applied to the substrate in reduced form, such as CrII compounds. The resultant catalyst is very active for oligomerizing olefins at a temperature range from below room temperature to about 250C, preferably 90-250C, most preferably 100-180C, at a pressure of 10.1 kPa (0.1 a~mosphere) to 34500 kPa (5000 psi). Contact time of both the olefin and the catalyst can vary from one second to 24 hours. The weight hourly space velocity (WHSV) is 0.1 to 10, based on total catalyst weight. The catalyst can be used in a batch type reactor or in a fixed bed, continuous-flow reactor.
In general the support material may be added to a solution of the metal compounds, e.g., acetates or nitrates, etc., and the mixture is then mixed and dried at room temperature. The dry solid 2i gel is purged at successively higher temperatures to 600C for a period of 16 to 20 hours. Thereafter the catalyst is cooled down :
under an inert atmosphere to a temperature of 250 to 450C and a stream of pure reducing agent is contacted therewith for a period when enough CO has passed through to reduce the catalyst as indicated by a distinct color change from bright orange to pale blue. Typically, the catalyst is treated with an amount of CO
equivalent ~o a two-fold stoichiometric excess to reduce the catalyst to a lower valence CrII state.Finally the catalyst is - -cooled down to room temperature and is ready for use.

F-4862t4872) - 18--The product oligomers have a very wide r~nge of viscosities with high viscosity indices suitable ~or high performance lubncation use. The product oli~omers also ha~e atactic molecular structure of mostly unifonm head-to-tail connections with sone s head-to-head type connec~ions in ~he structure. These low branc~ratio oligomers have high viscosity indices ~t least 1~ to 20 units and typically 30-40 units higher than equivalent viscosity prior art oligo~ers, which regularly have hi8her branch ratios and correspondin~ly lower viscosity indices. These low bran~h oligomers maintain better or comparable pour points.
The branch ratios defined as the ratios o~ ~H3 groups to CHz gro~ps in the lube oil are calculated from the weight fraotions of ~e~hyl gro~ps obtained by in~rared melhods, published Ln ~ , Vol. 25, No. 1~, p. 1466 (1953).
~5 Branch ratio - wt fraction of methyl group l-twt fraction of methyl group) As referenced hereinbefore, supported Cr metal oxide in different oxidation states is known to poly~erize alpha ole~ins from 2~ C3 to CzO (De 3427319 to H. L. Krauss and J~urnsl of C~talysis 88, 424-430, 1984) usin~ a catalyst prepared by CrO3 on silica.
The referenced disclosures teach that pol~merization takes place at low tempe~ature, usually less than 100 C, to give adhesive polymers and that a~ high temperature, the catalyst promotes iso~erization, cracking and hydrogen transfe~ reactions. The present inventions produce low molecular weight oligo~eric products under reaction c~ditions and using catalysts which minimize side reactians such as l-olefin is~merizaticn, cracking~ hydr~gen ~ransfer and aromatization. To produce t~o novel low molecular weight produ~ts suitable for use as lube ~asestock or as blending ``
stock with other lube stock, the rescticn o~ the present invention is car n ed ou~ at a temperatur~ higher (9o~250P C) than the .

~ ' .

~-4&62(4872) --l9--temperature suitable to produce high molecular weight polyalpha-olefins. The catalysts used in the present invention do not cause a significant amount of side reactions even at high temperature when oligomeric, low molecular wei~ht fluids are produced.
The catalysts for this invention thus minimize all side reactions ~ut oligomerize alpha olefins to give low molecular weight polymers with high efficiency. It is well known in the prior art that chromium oxides, especially chromia with average +3 oxidation states, either pure or supported, catalyze double bond isomerization, dehydro~enation, cracking, etc. Although the exact nature of the supported Cr oxide is difficult to determine, it is thought that the catalyst of the present invention is rich in Cr(II) supported on silica, which is more active to catalyze alpha-olefin oligomerization at high reaction temperature without causing significant amounts of isomerization, cracking or hydrogenation reactions, etc. However, catalysts as prepared in the cited references can be richer in Cr (III). They catalyze alpha-olefin polymerization at low reaction temperature to produce high molecular weight pol~ners. However, as the references teach, undesirable isomerization, cracking and hydrogenation reaction takes place at higher temperatures. In contrast, high temperatures are needed in this invention to produce lubricant products. The prior art also teaches that supported Cr catalysts rich in Cr(IlI) or higher :
oxidation states catalyze l-butene isomerization with 103 higher activity than polymerization of l-butene. The quality of the catalyst, method of preparation, treatments and reaction conditions are critical to the catalyst performance and compositicn of the product produced and distinguish the present invention over the prior art.
In the instant invention very low catalyst concentrations based on feed, from lO wt% to O.Ol wt%, are used to produce oligomers; whereas, in the cited references catalyst ratios based on .
' ' ~' F-4 862 ( 4872 ) --20--feed of 1.1 are used to prepar¢ high polymer. Resorting tO lower catalyst concentrations in the present invention to produce lower molecul~r weight material runs counter to conventional polymerization theory, compared to the results in the cited -references.
The oligomers of l-olefins prepared in chis invention usually have muoh lawer molecular weights than the polymers produced in the ~ted references which are senu-so~ds,~nth very kigh molecL~ar weights. These high polymers are not suitable as lub n ¢ant b~sestocks and usually have no detectable amount of dimer or b~m er (Clo-C3~) compcnen~s from syn~hesis. Such high polymers also have very low unsatura~ions. However, products in this invention a~e free-flowing liquids at room te~perature, suitable for lube basestock, containing significant amount of dimer or trimer and lS have high unsaturations.
The ~ollowing examples o the instant invention are presented merely for illustration purposes and are not intended to limit the scope of the present invention. :
ExamDle 1 1.9 ~Trams of chromiu~ (II) a~etate :~ .
(Cr2(000CH3)42H20)(S.58 mmole) ~commerciall~ obtained) is dissolYed in ;0 ml of hot acetic acid. Tn~n 50 ~rams of a silica gel of 8-12 mesh size, a surface area o~ 300 m2/g, and a pore volume of 1 ml/g, also is added. .~ost of the solution is absorbed by the silica gel. The final mixture is mixed ~or half an hour on a rotavap at roon tempera~ure and dried in an open-dish at :~-room temperature. First, the dry solid (20 g) is p~rged w~th N2 3~ at 25QC in a tube furnace. The furnace temperature is then r~ised to 400C for 2 hours. ~he temperature is tben set at 600C ~ith dry ~ :
air pur3ing for 16 hours. At this time the catalyst is cooled dOT~n under ~T2 to a tempe~ature of 300C. Then a stream of pure C0 ::
,, ., ,'~.' '' .. .. . , . , . , , . .. .. ~. . . " . . . . . .

1 32502~ -. ..
F-4862(4872) --21--. , (99.99~ from Matheson) is introduced for one hour. Finally, the catalyst is cooled down to room temperature under N2 and ready for use.
Example 2 The catalyst prepared in Example 1 (3.2 g ) is packed in a 3/8" stainless steel tubular reactor inside an N2 blanketed dry box. The reactor under N2 atmosphere is then heated to 150C by a single-zone Lindberg furnace. Pre-purified l-hexene is pumped into the reactor at 965 kPa (140 psi) and 20 ml/hr. The liquid effluent :
is collected and stripped of the unreacted starting material and the low boiling material at 6.7 kPa (0.05 mm Hg). The residual clear, colorless liquid has viscosities and VI's suitable as a lubricant - base stock.
- Sample Prerun 1 2 3 :.:
T.O.S., hr. 2 3.5 5.5 21.5 Lube Yield, wt~ 10 41 74 31 Viscosity, mm2/s (cs), at 40C 208.5 123.3 104.4 166.2 100C 26.1 17.1 14.5 20.4 Example 3 -: :, Similar to Example 2, a fresh catalyst sample i9 charged into the reactor and l-hexene is pumped to the reactor at 101 kPa (1 atm) and 10 ml per hour. As shown below, a lube of high viscosities and high VI's is obtained. These runs show that at different re2ction conditions, a lube product of high viscosities can be obtainsd.

1 3~5;02~

F-4862(4872) --22--Sample A g T.O.S., hrs. 20 44 ~e~np., C 100 50 ~ube Yield, ~ 8.2 8.0 - -Viscosities~ 0m2/s ~cs) at :
40~C 13170 19011 1~0C 620 1~48 o vr 217 263 ; .

~ ' ' .
A commercial chrome/silica catalyst which contains 1% Cr on a large-pore volume synthecic silica gel is used. The catalyst is - :
first calcined with air at 800C or 16 hours and reduced with 00 at 300C for 1.5 hours. Then 3.5 g of the catalyst is packed into a :
tubular reacto~ and heated to 100C undor a N2 a ~ osphere.
1-Hexene is pumped through at 28 ml per hour at 101 kPa (1 atmosphere). Thc products are collected and analyzed as follows: -.~:
Sample C D E F -T,O.S., hrs. 3~5 4.5 6.5 22.5 Lube Yield, ~ 73 64 59 21 25Viscosity, mm2/s (cs), at 40~ 2548 2429 3315 9~31 ~ ~-V~ 108 164 174 199 These runs show that different Cr Qn a silica ca~alyst are also effective for oligomerizing olefins to lube products~ -~ .' ~-4862( 4872) --23--Example 5 As in E~cample 4, purified 1-dece~e is plJmped through the reactor at 1830 kPa to 2310 kPa (250 to 320 psi). The product is ::
eollected periodically and stripped o~ light products boiling points S below 343C (~504F). High quality lubes with high VI are obtained (see following table). :. ~
; ,: .
Reacticnl~;V Lube Product Properties T~np.C~/g/hr V at 4ûC V at 100C VI
120 2.5 lSSS.4cs lS7.6cs217 :
135 0.6 38g.4 53.~ 202 ~
150 1,2 ~66.8 36.2 18S - . -166 0 .6 67.7 12. 3 181 :
197 0.5 21.6 5.1 172 Exa~ple 6 -:
As~n~ar catalyst is used in testing 1-hexene ~o oligomerization at di~ferent temperature. l-Hexono is fed at 28 :.
ml/hr and at ~1 kPa ~1 atmosphere). :
~ G H
Temperature, C 110 200 Lube Yield, wt,~ 46 3Viscosities, mm2/s (cs) at 3~ 100C 206 47 F-4862(4872) --24--Example 7 1.5 grams of a similar catalyst as prepared in Example 4 was added to a two-neck flask under N2 atmosphere. Then 25 g of l-hexene was added. The slurry was heated to 55C under N2 ~-atmosphere for 2 hours. Then some heptane solvent was added and the catalyst was removed by filtration. The solvent and unreacted starting material was stripped off to give a viscous liquid with a 61~ yield. This viscous liquid had viscosities of 1536 and 51821 mm2/2 (cs) at 100C and 40C, respectively. This example demonstrated that the reaction can be carried out in a batch `
operation.
The l-decene oligomers as described below were synthesized by reacting purified l-decene with an activated chromium on silica catalyst. The activated catalyst was prepared by calcining chromium acetate (1 or 3% Cr) on silica gel at 500-800C for 16 hours, -followed by treating the catalyst with C0 at 300-350C for 1 hour.
l-Decene was mixed with the activated catalyst and heated to reaction temperature for 16-21 hours. The catalyst was then removed and the viscous product was distilled to remove low boiling 2~ components at 200C/13.3 kPa(0.1 mmH4).
Reaction conditions and results for the lube synthesis of HVI-PA0 ar.e summarized below:

Table 1 l-decene/
Example Cr on Calcination TreatmentCatalyst Lube -NO. Silica Temp. Temp. Ratio Yld . .
8 3wt% 700C 350C 40 90 1 500 350 45 86 ~ -11 1 600 350 16 92 ~ ~

- : .

F-4862(4872) --25--Branch Ratios and Lube Properties of Examples 8-11 Alpha Olefin Oli~omers Table 2 ExampleBranch CH3 V40CV190C VI
No. Ratios CH2 8 0.14 lS0.522.8 181 9 0.15 301.440.1 186 0.16 1205.9128.3 212 -11 0.15 5238.0483.1 271 Branch Ratios and Lubricating Properties of Alpha Olefin -lSOligomers Prepared in the Prior-Art Table 3 Example Branch CH3 V40C V100C VI
2~ No. Ratios CH2 12 0.24 28.9 5.21 136 13 0.19 424.6 41.5 148 14 0.19 1250 100 168 0.19 1247.4 98.8 166 These samples are obtained from the commercial market.
They have higher branch ratios than samples in Table 2. Also, they have lower VI's than the previous samples.
Comparison of these two sets of lubricants clearly demonstrates that oligomers of alpha-olefins, as l-decene, with branch ratios lower than 0.19, preferably from 0.13 to 0.18, have higher VI and are better lubricants. The examples prepared in - . , ~ . . . . . . . . . . .

F-4862( 4872) --2 6--accordance with this invention have branch ratios of 0.14 to 0.16, providing lube oils of excellent quality which have a wide range of viscosities from 3 to 483.1 cs at 100C with viscosity indices of ~ -130 to 280.
Example 16 . . .
A commercial Cr on silica catalyst which contains 1% Cr on a large pore volume synthetic silica gel is used. The catalyst is first calcined with air at 700C for 16 hours and reduced with C0 at 350C for one to two hours. 1.0 part by weight of the activated catalyst is added to l-decene of 200 parts by weight in a suitable reactor and heated to 185C. l-~ecene is continuously fed to the reactor at 2-3.5 parts/minute and 0.5 parts by weight of catalyst is added for every 100 parts of l-decene feed. After 1200 parts of l-decene and 6 parts of catalyst are charged, the slurry is stirred for 8 hours. The catalyst is filtered and light product boiled below 150C Q O.lmm ~g is stripped. The residual product is hydrogenated with a Ni on Kieselguhr catalyst at 200C. The zo finished product has a viscosity at 100C of 18.5 mm2/s(cs), VI of 165 and pour point of -55C.
Example 17 Similar as in Example 16, except reaction temperature is 125C. The finished product has a viscosity at 100C of 145 mn /s(cs), VI of 214, pour point of -40C.
Example 18 Example 16 is repeated except reaction temperature is 100C. The finished product has a viscosity at 100C of 298 cs, VI
of 246 and pour point of -32C.
The final lube products in Example 16 to 18 contain the foll~ing amounts of dimer and trimer and isomeric distribution ~ -(distr.).

~-4862(4~72) --27--. . ' . .

V @100C, mm /s 18.5 145 298 Pour Point,~ -SS~ -40C -32 wt~ dimer 0.01 0.0} 0.027 wt% isomeric distr. dime~
n-eicosane 51~ 28% 73%
9-methylnonacosane 49~ 7~ 27%
wt~ trimer 5,53 ~.79 O.Z7 lo wt~ isomeric distr. trimer ll-octyldocosane 55 48 44 9-me~hyl,ll-octyl-heneicosane 35 49 40 others 10 13 16 These three examples demonstrate that the ne~ HVI-PA0 of ~ide viscosities contain the d~mer and trimer o~ unique structures in various proportiQns.
The molecular weights and ~olecular weight dist~ butions are analyzed by a high pressure llqult chromatography, composed of a constametric rI high pressuro, dual piston pump ~rom Milton Roy Co.
and a''Tracor'~45 LC detector. During analysis, the system pressure ~-is 4600 kPa (650 psi) and T~F solvent (~PLC grade) deliv¢r rate is 1 ml per m mute. The detector block t~perabure is set at 145 C.
ml of sample, prepared by dissolving 1 gram PA0 sample in ml T~F -solvent, is injected into the chromatograph. The sa~ple is eluted ~-over the ~sllowing columns in series,all from Waters Associates~
- Utrastyra~e~ 105 A, P/N 10574.'-UtrastyrageI lD4 A, P~N 1~573, Utrastyrager ~ A, P/N 1057~, Utrastyrager ~00 A, P/N 10571. The mo~ecu~ar weights ax ealibrat~d against commercially available PA0 from Mobil C~mical Co, Mobil*SHF-61 and SHF-81 ~nd SHF-401.
T~ follcwing table sumna~zes the mo~e~ul~r weights and dist~i~utions of ~xamples 16 to 18.

* Trademark (each instance) F-4862(4872) --28--Examples 16 17 18 V @100 C,mm2/s(cs) 18.5 145 298 number-averaged molecular weights, MWn 1670 2062 5990 weight-averaged molecular weights, ~W_w 2420 4411 13290 molecular weight 1o distribution, MWD 1.45 2.14 2.22 Under similar conditions, HVI-PAO product with viscosity as low as 3 mm /s (cs) and as high as 500 mm2/s (cs), with VI
between 130 and 280, can be produced.
Ethene can be employed as a starting material for conversion to higher C6-C20 alpha olefins by conventional catalytic procedure, for instance by contacting ethene with a Ni catalyst at 80-120C and about 7000 kPa (1000 psi) using commercial synthesis methods described in Chem System Process Evaluation/Research Planning Report - Alpha-Olefins, report number 82-4. The intermediate product alpha olefin has a wide distribution range from C6 to C20 carbons. The complete range of alpha olefins from growth reaction, or partial range such as C6 to C14, can be used to produce a lube of high yields and high viscosity indices. The oligomers after hydrogenation have low pour points.
: , Example 19 An alpha olefin growth reaction mixture, as described above, containing C6-C8-C10-C12-C14-C16-C18 C20 of equal molar concentration is reacted with 2 wt. % activated Cr/SiO2 catalyst at 130C and under nitrogen atmosphere. After ~-225 minutes reaction time, the catalyst is filtered and the reaction ~ -mixture distilled to remove light fraction which boils below .,. ~`"~, ,~

1 325~20 F-4 8~2 ( 4872 ) - -2 9- -120C/0,1 n~n-Hg. The residual lube yield is 9S~ and has V100OC
~7.07 cS and V~ 195.

Exanlple 20 An eqLlimolar C6-C20 alpha ole~ mixture as described above is fed continuously over activated Cr/SiO2 catalyst packed in a tubular reactor. The results are sumn~ri~ed below.

Table 20 Starting SAMPLES Material A B C D
Temp, C -- 125 lS0 190 200 Pres., psig -- 310 ~00 250 280 WHSV, g/g/hr -- 1. 2 1. 2 1 . 21. 2 ,: .
Product Dis~ribu~ion, wt. ~ ;
I-C6' 4.7 0.3 ~.3 ~.S 11 l-C82 12.8 0 0.3 1.1 2 3 .--. ~-l-Clo- 22,0 1.8 1.8 2.3 4 6 - .
l-C12- 19.4 0.3 0.5 1.4 3 4 : -1-C14- 16 .0 0.9 0 .9 1. 94. 8 -C16= 11.0 0.6 0,4 1,9 4 3 -1-~18_ 7-7 0.8 1.3 2.7 6 0 l-Czo- 6.5 O.S 1.8 3.1 6,g .::
C20-C30 4,4 2.6 7.8 18.7 ~ .
Lube 0 90.S 90.1 78.347.5 :
2S Lube properties V100C' CS -- 75.11 51.2~ 12.1214.84 ::

E~amPle 21 :
.931 eql~molar olefin ~xture of C6-C8-C10-C12-~14 is reacted over Cr/SiO2 catalys~ similar to ~cample 2. The results are summarized in Table 21. ~ -.. ::
.:

F-486~(4872) --30--Table 21 Starting SAMP~ES Ma~e nal A B C D
Temp, C _ 120 150 190 2~4 Pres., psig -~ 250 Z10 200 200 WHSV, g/g/hr -- Z.5 2.5 2.5 z.5 Product Dist ~ bution, wt. ~
l-C6- 16.3 n.3 0.6 1. 2 6.9 ;;
l~Cg 25.~ 0.5 1 1 1 8 ~ 3 l-Clo- 26.3 5.6 2 9 2 7 lO 9 -C12~ 19.9 0.5 0 9 l 5 9 1 ..
l-C14- 12.4 o.o 1 1 3 2 7 4 C20-C30 0 0.0 S.l 23.8 18.7 :
Lube 0 93.0 88.4 65.8 42.7 ~:
Lube properties VlOO~C, cS -- lOl.99 46.31 17.977.31 :~
VI -~ 187 165 168 157 pour points ater H2,C -33 -43 ~50 -41 ~ -A ran~e of alpha olefins frcm ethyleno growth reactions and metathesis processes can be used to p mduce high quality lube by the present process, thus rendering the process ~heaper and the feedr,tock more ~e~le than ~r~Ing pure ~ ~e monomer.

~xample 22 : -~
The standard l-decene oligomerization synthesis proceture ~.
2s employed above is repeated at 125C using different Group Y~B met~l ;.
species, t~gsten or molydenum. ~ e W~lo treated porous substraee .:
is r~duced with GO at 46~C to provide 1 wt. % metal in reduced oxide s~ate. Moly~denum catalyst gi~es a 1% yielt of a ~iscous :
liquid. Tungsten gives C20 dim¢r o~ly.
The use of supported Group VIB oxidos as a catalyst tO :- -oligomerize olefins to produce low branch ratio lube products with ~.
low pour points was here~ofone unknown. Catalytic produçtion of ~ `-.' . ':

F-486Z(4872) --31--oligomers with structures having a low branch ratio which does not use a corrosive co-catalyst and produces a lube with a wide range of viscosities and good V.I.'s was also heretofore unknown and more specifically the preparation of lube oils having a branch ratio of less than about 0.19 was also unknown heretofore.
Although the present invention has been described with preferred embodiments, it is to be understood that modifications and variations may be resorted to, without departing from the spirit and scope of this invention, as those skilled in the art will readily understand. Such modifications and variations are considered to be within the purview and scope of the appended claims.

"... ., ... , ~. . . ..

Claims (35)

1. A liquid lubricant composition comprising C30-C1300 hydrocarbons, said composition having a branch ratio of less than 0.19, weight average molecular weight between 300 and 45,000, number average molecular weight between 300 and 18,000, molecular weight distribution between 1 and 5 and pour point below -15°C.

2. The composition of claim 1 wherein said hydrocarbons comprise C30-C1000 hydrocarbons and molecular weight distribution of about 2.5.

3. The composition of claim 1 wherein said hydrocarbons comprise alkanes or alkenes.

4. The composition of claim 1 having a viscosity index greater than 130 and viscosity at 100°C between 3 mm2/s and 750 mm2/s..

5. The composition of claim 1 having a C30 fraction with a branch ratio below 0.19, viscosity index greater than 130 and pour point below -45°C.

6. The composition of claim 1 wherein the composition comprises the polymeric residue of 1-alkenes taken from linear C6 - C20 1-alkenes.

7. The composition of claim 6 wherein said 1-alkenes comprise C8-C12 alkenes.

8. The composition of claim 6 wherein said polymeric residue comprises hydrogenated polymeric residue of said 1-alkenes.

9. The composition of claim 6 wherein said polymeric residue comprises poly 1-decene.

10. The composition of claim 9 wherein the polymeric residue of 1-decene has a molecular weight of about 422.

11. The composition of claim 10 having a viscosity index of about 134 and a pour point less than -45°C.

12. A liquid lubricant hydrocarbon composition having the recurring polymeric structure where n is 3 to 17 and x is 5 to 500.

13. The composition of claim 12 where n is seven and average x is at least fifteen.

14, The composition of claim 12 having a viscosity index greater than 130 and a pour point less than -15°C.

15. A hydrocarbon composition useful as a lubricant comprising a mixture of C30 alkanes consisting essentially of 9-methyl, 11-octylheneicosane and 11-octyldocosane.

16. The composition of claim 15 wherein the mole ratio of 9-methyl, 11-octylheneicosane to 11-octyldocosane is between about and 1:10 and 10:1.

17. The composition of claim 16 wherein said mole ratio is about 1:2 to 2:1.

18. A hydrocarbon composition useful as a lubricant comprising C30H62 alkanes having a branch ratio less than 0.19 and pour point below -15°C.

19. The composition of claim 18 wherein said alkanes have a viscosity between 3cs and 4cs at 100°C, viscosity index greater than 130 and pour point below -45°C.

20. A composition of matter comprising 11-octyldocosane having the structure,

21. A lubricant composition comprising the 11-octyldocosane of claim 20.

22. A process for the preparation of liquid hydrocarbons suitable as lubricant basestocks from alpha olefins containing 6 to 20 carbon atoms, or mixtures of such olefins, comprising: contacting said olefins under oligomerization conditions, at reaction temperature of about 90 to 250°C with a chromium catalyst on a porous support, which catalyst has been treated by oxidation at a temperature of 200°C to 900°C in the presence of an oxidizing gas and then by treatment with a reducing agent at a temperature and for a time sufficient to reduce said catalyst to a lower valence state;
to obtain an oligomeric liquid lubricant composition comprising C30-C1300 hydrocarbons, said composition having a branch ratio of less than 0.19, weight average molecular weight between 420 and 45,000, number average molecular weight between 420 and 18,000, molecular weight distribution between 1 and 5 and a pour point below -15°C.

23. The process of claim 22 wherein said reducing agent comprises CO, the oligomerization temperature is about 100-180°C, and the yield of C30 oligomer is at least 85 wt% for product having a viscosity of at least 15cS at 100°C.

24. The process of claim 23 wherein the support comprises porous silica.

25. The process of claim 23 wherein the olefin consists essentially of 1-octene, 1-decene, 1-dodecene, 1-tetradecene or mixtures thereof.

26. The process of claim 22 wherein said catalyst is not subjected to a further oxidation step after said reduction.

27. The process of claim 22 wherein said olefins comprises 1-decene, and the oligomer has a VI of 181 or greater and a branch ratio of from about 0.14 to 0.16.

28, A process for oligomerizing alpha olefins to produce lubricant range hydrocarbon stock including the step of contacting said alpha olefins with a supported solid reduced metal oxide catalyst under oligomerization conditions at a temperature of about 90 to 250°C; said metal oxide comprising a lower valence form of at least one Group VIB metal, whereby the lubricant range hydrocarbon product has a branch ratio from about 0.10 to about 0.16 and a viscosity index of at least about 130.

29. The process of claim 28 wherein said alpha olefins comprise olefinic hydrocarbons having 8 to 14 carbon atoms or mixtures thereof; wherein the process conditions include reaction temperature of about 100 to 180°; ant wherein said support catalyst includes a porous inert support having a pore opening of at least 40 Angstroms.

30. The process of claim 29 wherein the process conditions are controlled to oligomerize alpha olefins without isomerizing double bonds therein.

31. The process of claim 29 wherein said catalyst comprises chromium oxide prepared by treating an oxidized chromium oxide with a reducing agent for a time sufficient to reduce said chromium oxide.

32. A process for oligomerizing alpha olefins to produce lubricant range hydrocarbons including the step of contacting C6-C20 alpha olefins with a supported solid reduced metal oxide catalyst under oligomerization conditions at a temperature of about 90 to 250°C; said metal oxide comprising a lower valence form of at least one Group VIB metal to produce lubricant range hydrocarbon product having a branch ratio from about 0.10 to about 0.16 and a viscosity index of at least about 130.

33. A process for oligomerizing alpha olefins to produce lubricant range hydrocarbon stock including the step of contacting said alpha olefins with a supported solid reduced chromium catalyst under oligomerization conditions at a temperature of about 90 to 250°C to produce a liquid lubricant hydrocarbon composition comprising the polymeric residue of 1-alkenes consisting essentially of linear C6 - C20 1-alkenes, said composition having a branch ratio of less than 0.19, a weight average molecular weight between 420 and 45,000, a number average molecular weight between 420 and 18,000, molecular weight distribution between 1 and 5 and pour point below -15°C; and wherein the lubricant range hydrocarbon product has a viscosity index of about 130 to 280 and a viscosity up to about 750 mm2/s(cs).

34, The process of claim 33 wherein said alpha olefin consists essentially of hydrocarbons having 8 to 14 carbon atoms or mixtures thereof; wherein the process conditions include reaction temperature of about 100 to 180°C; and wherein said support catalyst includes a porous inert support.

35. The process of claim 33 wherein the oligomerization conditions comprise a reaction temperature of about 90°-250°C and feedstock to catalyst weight ratio between 10:1 and 30:1; said catalyst comprises C0 reduced CrO3, and said support comprises silica having a pore size of at least 40 Angstroms.