Note: Descriptions are shown in the official language in which they were submitted.
1 325020
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.
: :-
.. - ~ ... .. :, .. - , . . ~.
1 3~20
~4~
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.
,`'':
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.
'~
': .'
"' '
1 32~2~
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 ~ ,',
1 325020
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.
. ~,~ .
! ~
. .... ... . . . .
1 325020
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 -~
1 325020
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:
1 325020
g~z(4872) 9
H( ~ CH2-) ,C- (-CH2- 1 - ) ~,H . , ,
C~)3 ~CH2)3
CH3 CH3
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. ~`
:
.':
-'.
,: .`.
.
.,
~ ~ , ",' '"
. .
.. . . .
''i--`5 ,, . , ~,
5~_ ' .. `. ' ~
~'''.
, ~, ~ ..... . , . ' ' . ' .
1 325020
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
1 325020
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 '''.
: .-: '
'.. ':
. . .
:.
1 325020
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
CH3
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.
* Trademark
,
,. ' '
, .. ; i ' . .. ! ' ; . , ~ .: , '~ . . . .
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
1 325020
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~
.: ,
: ".
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.
,:
.
: - - .-: :, . . : ,~, . : :, :
1 325020
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.
1 325020
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 .
~ ' .
1 325020
~-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
.
' ' ~'
1 325020
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
VI 159 151 142 143 -
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 ~ ~-
100C 102 151 197 437
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~ -
~ .'
1 325020
~-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
40C 3512 3760
3~ 100C 206 47
VI 174 185
1 325020
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
9 3 700 350 40 9O
1 500 350 45 86 ~ -
11 1 600 350 16 92 ~ ~
- : .
1 325020
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
- . , ~ . . . . . . . . . . .
1 325020
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.).
1 325020
~-4862(4~72) --27--
. . '
. .
2 16 17 18
V @100C, mm /s 18.5 145 298
VI 165 214 246
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)
1 325020
F-4862(4872) --28--
Examples 16 17 18
V @100 C,mm2/s(cs) 18.5 145 298
VI 165 214 246
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 ::
VI -- 190 184 168 164
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. ~ -
.. ::
.:
1 325020
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 ~ `-
.' . ':
1 325020
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.
"... ., ... , ~. . . ..
