Note: Descriptions are shown in the official language in which they were submitted.
WO 90/10050 PGT/US9(f/t~i$63
W
NOVEL SYNTF~'TIC LUBE COt~OSITION AND PROCESS
This invention relates to novel compositions prepared from
synthetic lubricants by reaction with olefins and to the process for
their production. The invention particularly pertains to the
modification of a high viscosity index synthetic lubricant oligomer
fraction employing low molecular weight by-product oligomer
fractions as reactant. The modified synthetic lubricants are
themselves useful, inter alia, as lubricants with improved thermal
stability.
Efforts to improve upon the performance of natural 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 synthetic lubricants, primarily based on the
oligomerization of alpha-olefins or 1-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, while also showing lubricity, 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 cil lubricants.
One characteristic of the molecular structure of 1-alkene
oligomers that has been found to correlate very well wiah improved
lubricant properties in commercial synthetic lubricants is the ratio
of methyl to methylene groups in the oligomer. ~e ratio is called
the branch ratio and is calculated from infra red data as discussed
in "Standard Hydrocarbons of High Molecular Weight", Analytical
C~istry, Vo1.25, no. l0, p.1466 (1953).~Viscosity index has been
WO 90/10050 PCT/U590/00863
s,,,~,~~~. ~~7
r c~ ;~ ~ ~ =: :. _-2-_
found to increase with lower branch ratio. Until recently, as cited
herein, oligomeric liquid lubricants exhibiting very low branch
ratios have not been synthesized from 1-alkenes. For instance,
oligomers prepared from 1-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
involving 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
rearrangement, isomerization or a yet to be elucidated mechanism it
is clear that in the art of 1-alkene oligomerization to produce
synthetic lubricants as commercially practiced 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 would be
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. 'Ihe
branch ratio is not disclosed.
A process using coordination catalysts to prepare high
polymers from 1-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 uses low temperatures
to produce high polymer and does not disclose lubricants having
unique structure.
WO 90/10050 PC?/U590/008b3
_-3__
Recently, novel lubricant compositions (referred to herein
as HVI-PAO) comprising polyalpha-olefins and methods for their
preparation employing as catalyst reduced chromium on a silica
support have been disclosed in U.S. Patents 4,827,064 and
S 4,827,073. 'Ihe HVI-PAO lubricants are made by a process which
comprises contacting C6-C20 1-alkene feedstock with reduced
valence state chromium oxide catalyst on porous silica support under
oligomerizing conditions in an oligomerization zone whereby high
viscosity, high VI liquid hydrocarbon lubricant is produced having
branch ratios less than 0.19 and pour point below -15°C. The process
is distinctive in that little isomerization of the olefinic bond
occurs compared to known oligomerization methods to produce
polyalpha-olefins using Lewis acid catalyst. Lubricants produced by
the process cover the full range of lubricant viscosities and
exhibit a remarkably high viscosity index (VI) and low pour point
even at high viscosity. The as-synthesized HVI-PAO oligomer has a
preponderance of terminal olefinic unsaturation. Typically, the
HVI-PAO oligomer is hydrogenated to improve stability for lubricant
applications. Those modifications to HVI-PAO oligomers that result
in improved thermal stability are particularly preferred.
In the preparation of the novel HVI-PAO lubricant,
alpha-olefin diner containing olefinic unsaturation can be separated
from the oligomerization reaction. The composition of the diner
mixture conforms to the unique specificity of the oligomerization
reaction in that little double bond isomerization is found and shows
a law branch ratio. Separation of the diner, representing non-lube
range molecular weight material, is necessitated to control product
volatility and viscosity. However, as oligomerization conditions are
changed to produce the lower viscosity products of lower average
molecular weight important to the marketplace, the non-lube range
diner fraction by-product yield increases in proportion to that
lowering in average molecular weight of the oligomerization
product. The increase in diner by-product yield represents a
WO 90/10050 PCT/L'S90/OOf163
>~::,~,
hJ il .r .,? ~t ~ --4--
substantial economic burden on the overall process to produce useful
lower viscosity lubricant.
It would therefore be desirable to incorporate the non-lube
range fractions into the product in order to avoid the economic
penalty associated with the production of the lower viscosity
lubricants.
It has been found that the non-lube range olefins produced
in the oligomerization process can be effectively converted to lube
range products by reaction with the lube range material. It has also
been found that other olefins may also be used in a similar manner
and that the reaction products possess unexpectedly better thermal
stability than the original lube range material, regardless of the
character of the olefin. The yield of lubricant material is also
improved in this way.
According to the present invention, therefore, a method for
improving the thermal stability of synthetic lube produced by the
oligomerization of a 1-alkene (alpha-olefin) is provided which
method comprises reacting the oligomer with an olefin. The reaction,
which is believed to proceed mainly by alkylation with some side
reactions such as cracking, isomerization and polymerization, is
carried out in the presence of an alkylation catalyst under
conditions appropriate for alkylation.
A preferred olefin for reaction with the lube oligoceer is
the lower molecular weight, non-lubricant olefin produced in the
course of the oligomerization of the alpha-olefin starting material.
Using these lower molecular Weight materials in this way not only
improves the thermal stability of the final lube products but also
increases the product yield and olefin utilization, thus avoiding
the economic penalty attached to the production of the lower
viscosity range lubricants. In a preferred embodiment of the present
invention, therefore, the lower molecular weight non-lubricant range
olefinic hydrocarbons produced in the course of the oligomerization
of 1-alkenes are used to upgrade the lube range oligomer.
WO 90/10050 PCT/U590/00863
~~jl~ ~'
--5--
The reaction is carried out using acidic catalyst.
Effective acidic catalysts comprise alkylation catalysts, preferably
the open-pore catalyst such as those derived from fluorided alumina.
The composition of the present invention is polymeric
residue of linear C6-C20 1-alkenes, which has at least one
higher alkyl (C12-C40) branch per oligomer molecule. The
hydrocarbon oligomer generally contains fran 30 to 1300 carbon atoms
per molecule. In a preferred embodiment the novel composition has a
methyl to methylene branch ratio of less than 0.19 and pour point
l0 below -15°C.
The preferred process for the conversion of the
alpha-olefins to the desired thermally stable, high viscosity index
lubricant product comprises: contacting C6 to C20 alpha-olefin
feedstock, or mixtures thereof, under oligomerization conditions
15 with a reduced valence state Group VIB metal catalyst on porous
support whereby an oligomerization product mixture is produced
containing oligomers comprising olefinic lubricant range
hydrocarbons and olefinic non-lubricant range hydrocarbon
by-product; separating the lubricant and non-lubricant hydrocarbons
20 and hydrogenating the lubricant range hydrocarbons; contacting the
hydrogenated hydrocarbons and the olefinic by-product hydrocarbons
as alkylating agent in an alkylation zone under alkylating
conditions with acidic catalyst whereby alkylated lubricant range
hydrocarbons are produced.
25 In the drawings, Figure 1 shows the relationship between
degree of alkylation and viscosity loss for modified HVI-PAO.
Figure 2 shows the relationship between viscosity and
viscosity index for HVI-PAO oligomer and modified HVI-PAO oligomer.
In the preferred embodiments of the present invention
30 synthetic hydrocarbon lubricants are modified by reaction with
alkenes including the unique olefin diners produced as by-product in
the oligomerization reaction that produces the synthetic lubricant.
The alkenes which can be used to react with HVI-PAO oligomers as
WO 90/10050 p'CT/U~10/00863
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described herein include C2-C40 linear or branched alkenes but,
in particular, 1-alkenes and the olefinic diner by-product of the
NVI-PAO oligomerization reaction. Preferred 1-alkenes for reaction
with HUI-PAO oligomers include those olefins containing from 6 to 14
carbon atoms such as 1-hexene, 1-octene, 1-decene, 1-dodecene and
1-tetradecene and branched chain isomers such as 4-methyl-1-pentene.
Particularly preferred 1-alkenes are the C$ to C10
alpha-olefins, e.g., 1-octene, 1-decene and the olefin diners
produced in the oligomerization process for producing the initial
lube range materials.
The oligomerization reaction is carried out by the
oligomerization of 1-alkenes in contact with reduced metal
catalysts, preferably reduced chromium oxide on a silica support. A
characteristic of the novel oligomerization reaction from which the
by-product diners used as alkylating agent in the present invention
are produced is the production of mixtures of dialkyl vinylidenic
and 1,2 dialkyl or trialkyl mono-olefin oligomers, or HVI-PAO
oligomers, as determined by infra-red and NMR analysis. However, in
general, the HVI-PAO oligomers have the following regular
head-to-tail structure where n is preferably 0 to 17, terminating in
olefinic unsaturation:
_ ~~2-p.I~x-
~~2 ~n
~3
with some head-to-head connections.
The HVI-PAO process produces a surprisingly simpler and
useful diner compared to the diner produced by 1-alkene
oligomerization with BF3 or A1C13 as commercially practiced.
Typically, in the present invention it has been found that a
significant proportion of unhydrogenated dimerized 1-alkene, or
alpha-olefin, has a vinylidenyl structure as follows:
WO 90/10050 1'GT/US90/008b3
..
-_
CH2=CR1R2
where Rl and R2 are alkyl groups representing the residue froo
the head-to-tail addition of 1-alkene molecules. For example, the
by-product dimes from 1-decene oligomerization according to the
HVI-PAO process, which can be used as alkylating olefin in the
present invention, has been found to contain three major components,
as determined by gas chromatography (GC). Based on C-13 Mbt
analysis, the unhydrogenated components were found to be 8-eicosene,
9-eicosene, 2-octyldodecene and 9-methyl-8 or 9-methyl-9-nonadecene.
Olefins suitable for use as starting material in the
preparation of olefinic HVI-PAO oligomers and the by-product diner
used as starting material in the present invention include those
olefins containing from 6 to 14 carbon atoms such as 1-hexene,
1-octene, 1-decene, 1-dodecene and 1-tetradecene and branched chain
isomers such as 4-methyl-1-pentene. A preferred 1-alkene is
1-decene. Also suitable for use are olefin-containing refinery
feedstocks or effluents. However, the olefins used in this
invention are preferably alpha olefinic as for example 1-octene to
1-dodecene and more preferably 1-decene, or mixtures of such olefins.
The lube range HVI-PAO oligomers of alpha-olefins used in
this 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 class of .unsaturated HYI-PAO alpha-olefin oligomers
are prepared by oligomerization reactions in which a major
proportion of the double bonds of the alpha-olefins are not
isomerized. These reactions include alpha-olefin oligomerization by
3o 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,
WO 90/10050 PCT/LS90/00863
iJ ~ i :~ ~~'; --8__
titania, silica alumina, magnesia and the like. 'Ihe support
material binds the metal oxide catalyst. Those porous substrates
having a pore opening of at least 40 angstroms are preferred.
The support material usually has high surface area and
large pore volumes with average pore size of 40 x 10 ~mm to 3S0 x
10-~mm. 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-~mm, with an average pore opening of
60 x 10 ~mm to 300 x 10 ~mm 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 catalyst particle
attrition or disintegration during handling or reaction.
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 900°C 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,
C0, HZ, NH3, HZS, CSZ, CH3SCH3, CH3SSCH3,metal alkyl
containing compounds such as R3A1, R3B,RZMg, 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 250°C at a pressure of 10.1 kPa
WU 90/10050 PCT/LS90/UO$63
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,f. . ' ~~ "' ,~I rl
~~,jl~t.i~.
(0.1 atmosphere) to 34580 kPa (5000 psi). However, oligomerization
temperature is preferably between g0-250°C at a feedstock to
catalyst weight ratio between 10:1 and 30;1. Contact time of both
the olefin and the catalyst can vary from one second to 24 hours.
S 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
gel is purged at successively higher temperatures to 600°C for a
period of 16 to 20 hours. Thereafter the catalyst is cooled down
under an inert atmosphere to a temperature of 250 to 450°C 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 to a two-fold stoichiometric excess to reduce the
catalyst to a lower valence CrII state.Finally the catalyst is
cooled to room temperature and is ready for use.
The product oligomers have a very wide range of viscosities
with high viscosity indices suitable for high performance
lubrication use. The product oligomers also have atactic molecular
structure of mostly uniform head-to-tail connections with some
head-to-head type connections in the structure. These low branch
ratio oligomers have high viscosity indices at least 15 to 20 units
and typically 30-40 units higher than equivalent viscosity prior art
oligomers, which regularly have higher branch ratios and
correspondingly lower viscosity indices. these low branch oligomers
maintain better or comparable pour points.
The branch ratios defined as the ratios of CH3 groups to
CH2 groups in the reaction products and by-products are calculated
from the Weight fractions of methyl groups obtained by infrared
methods, published in Analytical Chemistry, Vol. 25, No. 10, p. 1466
(1953).
WO 90/10050 PCT/U590/00f363
--10--
'i1 ~ ~ ':7 ~j
Branch ratio = wt fraction of methyl grou
1- wt taco on o met y group)
The unique olefinic diners used as alkylating agent in the
present invention are produced as by-product of the HVI-PAO
oligomerization reaction. Typically, in the production of HVI-PAO
oligomer lubricant base stock, the oligomerization reaction mixture
is separated from the catalyst and separated by vacuum distillation
to remove unreacted alpha-olefin and lower boiling by-products of
the oligomerization reaction, such as alpha-olefin diner. 'Ibis
provides a lubricant basestock of suitably high volatility and
viscosity. While other methods known to those skilled in the art,
such as solvent extraction, may be used to separate the alpha-olefin
diner by-product, distillation is preferred.
The following examples are presented to illustrate the
oligomerization reaction and lubricant grade oligomers produced
therefrom. The reaction provides as a by-product the olefinic diner
used as alkylating agent or reactant in the present invention. 'Ihe
diner is separated by distillation from the oligomerization reaction
mixture.
Example 1
Catalyst Preparation and Activation Procedure
1.9 grams of chromium (II) acetate
(Cr2(OCOCH3)4ZH20) (5.58 mmole) (commercially obtained) is
dissolved in SO ml of hot acetic acid. Then SO grams of a silica
gel of 8-12 mesh size, a surface area of 300 m2/g, and a pore
volume of 1 ml/g, also is added. Most of the solution is absorbed
by the silica gel. The final mixture is mixed for half an hour on a
rotavap at room temperature and dried in an open-dish at room
temperature. First, the dry solid (20 g) is purged with N2 at
250°C in a tube furnace. The furnace temperature is then raised to
400°C for 2 hours. The temperature is then set at 600°C with dry
air purging for 16 hours. At this time the catalyst is cooled under
WO 90/10050 P'Ct/U590/OU863
,<
~~~~~ >~= 1
--11--
N2 to a temperature of 300°C. Then a stream of pure CO (99.99:
from Matheson) is introduced for one hour. Finally, the catalyst is
cooled to room temperature under N2 and ready for use.
Example 2
The catalyst prepared in Example 1 (3.2 g ) is packed in a
9.5 mm (3/8") stainless steel tubular reactor inside an N2
blanketed dry box. The reactor under N2 atmosphere is then heated
to 150°C by a single-zone Lindberg furnace. Pre-purified 1-hexene
is pumped into the reactor at 1069 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.x, hr. 2 3.5 S.S 21.5
Lube Yield, wt% 10 41 74 31
Viscosity, mm2/s (cS), at
40°C 208.5 123.3 104.4 166.2
100°C 26.1 17.1 14.5 20.4
VI 159 151 142 143
~'fime on stream
Example 3
A commercial chrome/silica catalyst which contains 1% Cr on
a large-pore volume synthetic silica gel is used. The catalyst is
first calcined with air at 800°C for 16 hours and reduced with CO at
300°C for 1.5 hours. Then 3.5 g of the catalyst is packed into a
tubular reactor and heated to 100°C under the N2 atmosphere.
1-Rexene is pumped through at 28 ml per hour at 101 kPa (1
atmosphere). The products are collected and analyzed as follows:
WO 90/10050 PCf/U590/UO$h3
--12--
r
'J '-
Sa_ mple C D E F
T.O.S., hrs. 3.5 4.5 6.5 22.5
Lube Yield, 90 73 64 59 21
Viscosity, mm2/s(cS), at
40°C 2548 2429 3315 9031
100°C 102 151 197 437
VI 108 164 174 199
Since the lubricants prepared by the methods described
above contain olefinic unsaturation they are typically hydrogenated
l0 to stabilize them for lubricant use. However, very high molecular
weight oligomers may not need to be hydrogenated since the number of
olefin bonds in such oligomers is comparatively small. Lower
molecular weight oligomers of particular interest in the present
invention to provide low viscosity lubricants are hydrogenated by
means well known to those skilled in the lubricant arts.
In the present invention, the thermal stability of the
hydrogenated lubricant range oligomers is improved by reaction with
an olefin, preferably the non-lube range olefins produced as a
by-product in the oligomerization reaction. Without wishing to be
held by theoretical consideration, the reaction employed herein to
modify HVI-PAO oligomer is described as an alkylation reaction and
the reactant alkene as an alkylating agent. Although alkylation is a
significant reaction occurring in the instant invention carried out
~mder alkylation conditions, other reactions are occurring as well,
e.g., cracking, isomerization and polymerization. Accordingly, the
term alkylation as used herein includes all those reactions
occurring that result in the beneficial modification of HVI-PAO
oligomers as herein described.
The catalyst used in the alkylation reaction of the present
invention is preferably a porous, solid acidic catalyst containing
large pore openings. A preferred catalyst is a fluorided alumina,
prepared as described hereinafter. Other useful solid catalysts
WO 90/10050 YCT/U590/00863
~~ < '~ ~' ~ r,
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--13--
include acidic zeolites. Zeolites useful as catalysts in the
present invention include all natural or synthetic acidic large pore
size zeolites, typically with a pore size of 6.4 x 10 7mm to 7.S x
10-7mm. In addition to fluorided alumina, particularly useful
catalysts include the acidic form of ZSM-4, Zit-12, ZS'ri-20,
Faujasite X $ Y with pore size of 7.4 x 10 7mm (7.4 Angstroms),
Cancrinite, Gmelinite, Mazzite, Mordenite and Offretite. Other
alkylation catalysts which are also useful in the process of the
present invention include conventional alkylation catalysts known to
those skilled in the art including HF, A1C13, BF3 and BF3
complexes, SbClS, SnCl4, TiCl4, P20S, H2S04, ZnCl2
and acidic clays.
The alkylation reaction of the present invention produces
alkylated synthetic lube containing large alkyl branches. The alkyl
branches preferably contain between 12 and 40 carbon atoms, or
mixtures thereof, depending on the olefin used in the alkylation
reaction, e.g, the diner of the C6-C20 alpha-olefin. Branches
containing between 2 and 40 carbon atoms can be produced when
monomeric olefins, e.g. ethylene, propylene, 1-decene, are used as
alkylating agent. The degree of large branching, i.e. branching
introduced by the olefin, can be controlled by the mole ratio of.
alkene such as diner olefin to synthetic lube in the alkylation
reaction. In general, the molar ratio of olefin to the lube range
material will be between 40 to 1 and 1 to 1, preferably between S to
1 and 1 to 1 molar ratio. As a result the product characteristics
can range from synthetic lube containing at least one large alkyl
group per mole to a reaction product containing a mixture of
alkylated synthetic lube and synthetic lube. Surprisingly, it has
been found that when the synthetic lobe is HVI-PAO oligomer,
alkylation with alkene diner according to the present invention
produces an alkylated product that maintains the high VI and low
pour point of the unalkylated HVI-PAO oligomer and shows an increase
in thermal stability.
WO 90/10050 YCT/US90/b0$63
~~~r~sjL~~r~
--14--
The following Examples illustrate the preparation of a
preferred alkylation catalyst of the present invention and further
illustrate the novel alkylation reaction.
Example 4
Alkylation Catalyst Preparation
25 grams of alumina ( Narshaw Catapal-S, 0.8 mm (1/32 inch)
extrudate) is contacted with 15.8 grams of aluminum nitrate nova
hydrate in 30m1 water for 1 hour. After the contact, excess water is
removed under reduced pressure at 80°C. The aluminum nitrate
impregnated alumina is then contacted with 8.17 grams ammonium
fluoride in SOml water to form aluminum fluoride in the alumina. 'Ihe
aluminum fluoride/alumina catalyst is dried under vacuum at 115°C
for 18 hours and then calcined at 538°C for 12 hours.
Example 5
Synthetic Lube/Dimer Preparation
Synthetic lube is prepared according to the process for
HVI-PAO reacting 1-decene over chromium supported silica as
previously described herein. The unsaturated decene diner is
separated by distillation as a by-product to remove unreacted decene
and lubricant product hydrogenated. The lube product viscosity was
9.2 uan2/s (9.2cS), measured at 100°C:
Example 6
Alkylation of HVI-PAO Lube
Alkylation reactions are performed in a fixed-bed reactor.
The unit is maintained at 2861 kPa (400 psig) and the liquid hourly
space velocity (LHSV) is 0.5. The feed is a mixture of 315 grams of
1-decene HVI-PAO lube and 140 grams of 1-decene diner representing
30.8 weight percent. Alkylation reactions are carried out at
reaction temperatures of 167, 204 and 250°C, Examples 7-1, 7-2 f,
7-3. The results of these alkylation reactions are presented in
Table 1
WO 90/ 10050 f'CT/ U590/00f3b3
~~j~~3~i~s
--1S--
Table
1
Example Feed7-1 7-2 7-3
Reaction Temp. C - 167 204 250
- 0.5 0.5 O.S
Pressure, kPa(PSIG)- 2861(400)2861(400)2861(400)
HVI-PAO Charged,gms - 40.3 50.3 46.2
HVI-PAO recovered,gms- 46.7 57.3 50.1
weight increase - 15.9 13.9 8.4
KV, 40C 50.074.0 79.5 70.5
KV, 100C 9.2 11.7 12.1 11.3
Viscosity Index(VI) 167 153 148 154
Molecular Weight 710 786 795 825
Based upon the initial percent of HVI-PAO present in the
feed, the amount of HVI-PAO fed can be calculated and is fotmd in
Table 1 for each example. After alkylation, a weight increase is
expected and is noted in the table. Weight increases vary between
8.4 and 15.9 percent and appear to be a function of reaction
temperature.
With this method the overall yield of final product is
increased by the addition by alkylation of diner by-product to the
synthetic HVI-PAO lubricant. The alkylated product has an increased
viscosity compared to the starting HVI-PAO lubricant and maintains
the high VI characteristic of these oligomers.
Tie following examples further illustrate the process of
the present invention. Surprisingly, as illustrated hereinafter, it
has been discovered that the proeess of alkylation imparts a
substantial increase in the thermal stability of the resulting
lubricants. Unalkylated HVI-PAO loses 35% of its viscosity,
measured at 100°C, when subjected to a temperature of 300°C for
24
hours in an inert environment. When the same HVI-PAO is alkylated
with by-product diner, to the extent of 30% alkylation, the
viscosity loss is reduced to 10%.
WO 90/10050 PCT/U590/00$63
t~ i:: ~:~'i s __16--
Example 7
Catalyst Preparation
2S grams of alumina is contacted with a solution comprised
of S.3 grams of alumina nitrate (nova-hydrate) in 30m1 of water for
one hour. Excess water is removed by vacuum. The dried alumina
nitrate impregnated alumina is then contacted with another solution
containing 2.7 grams of ammonium fluoride in SOml of water. After
five minutes the excess water is decanted and the resulting
fluorided alumina is dried in vacuum at 9S°C for three days. This
to catalyst contains S% aluminum fluoride.
Example 8
Alkylation Reaction
7.0 grams of the above fluorided alumina catalyst is placed
into a fixed-bed reactor and calcined at S38°C for 18 hours. A feed
comprised of 300grams (61.2: by weight) of a 18.9mm2/s(cS)
(@100°C) HVI-PAO and 190 grams (38.8% by weight) o~ by-product
decene diners is passed over the fluorided alumina catalyst under
condition found in Table 2 for Examples 9-1, 9-2 and 9-3. The degree
of alkylation is measured by the percent weight increase of the
examples. The degree of alkylation varies from 7.5 to 30.6:.
In Table 3 the results of the thermal stability studies on
the above alkylation products is presented. The unalkylated HVI-PAO,
when subjected to a temperature of 300°C for 24 hours in an inert
atmosphere losses 35.4 of its viscosity, measure at 100°C. As the
degree of alkylation is increased the stability of the alkylated
HYi-PAO increases. At 30.6 alkylation the viscosity loss is reduced
to 10.1 ( @ 100°C).
In the figure the relationship between degree of alkylation
and viscosity loss is presented. This demonstrates the increased
thermal stability of alkylated HVI-PAO, according to the present
imiention.
WO 90/10050 PCT/US90/OOSh3
~'s1~ ~ 3'
--17--
Table 2
Example Feed 9-1 9-2 9-3
Reaction Temp. C - 138 139 139
- 0.5 0.5 0.5
Pressure, kPa(PSIG) - 2861(400) 413(350)2413(350)
2
HVI-PAO Charged,gms - 22.2 23.8 53.0
HVI-PAO recovered,gms 29.0 26.7 57.0
-
% weight increase - 30.6 12.2 7.5
KV, 40C 18.9 15.4 17.0 16.5
KV, 100C 130.9 103.6 115.2 108.5
Viscosity Index(VI) 164.1157.5 161.3 165.3
Molecular Weight 1054 871 997 978
Table 3
Thermal Stability (300C for
24
hours)
Before thermal treatment treatment
After thermal
Example KV,40-~ KV,l00~C VI KV,40- ,100-C VI : loss
*
HVI-PAO 130.9 18.9 164 75.9 12.3 15935.4
9-1 103.6 15.4 158 91.3 13.9 15510.1
*
g-2 115.2 17.0 161 84.7 13.5 16320.4
9-3 108.5 16.5 165 74.8 12.3 16325.7*
*based on 100C viscosity loss
In the following Example, HVI-PAO is alkylated as described
above using the same fluorided alumina catalyst, except 1-decene
alone was mixed with the HVI-PAO for reaction instead of HVI-PAO
diner.
WO 90/10050 YCT/US9()/t~$63
'l ::~ ~~'~' -_18--
Example 9
18.9mm2/s (cS) HVI-PAO Oligomer alkylated with 1-decene
Conditions:
Reaction temp, °C 169
Pressure, kPa (psig) 2861(400)
LHSV 0.4
FNI-PAO charged, gms 30.7
Results:
HVI-PAO recovered, gms 36.6
% weight increase 19.2
IN, 40C 13.1
KV, 100C 84.7
VI 155.6
Table 4 presents the thermal stability test results on the
product of Example 9.
Table 4
KV,40°C KV,100°C VI % Loss
Before Thermal Treatment 84.7 13.1 156 ---
After Thermal Treatment 75.7 12.0 154 8.4
Figure 2 shows a comparison of viscosity and VI for
unreacted vs reacted HVI-PAO illustrating that VI remains unchanged
for the reacted product of the invention.
While the invention has been described with preferred
embodiments, the inventive concept is not limited except as set
forth in the following claims.
