Note: Descriptions are shown in the official language in which they were submitted.
2116070 :~
T 9018
OLIGOMERISATION PROCESS
The invention relates to a process for preparing liquid
organic compounds, suitable as base materials for lubricants, which
process involves a catalytic oligomerisation reaction.
It is known that oligomers of propylene may be used as base
materials for preparing lubricating oils. As is apparent from some
earlier publications, propylene oligomers with a polymerisation
degree of mainly 2 to 10 and containing vinyl-end groups, have been
considered of particular interest. For example, in EP-A-268 214,
propylene oligomers having a polymerisation degree of mainly 2 to
10 and containing vinyl end-groups are prepared in high selectivity
by oligomerising propylene in the presence of a catalyst comprising
a transition metal compound and an organometallic compound, wherein
an alkyl-substituted cyclopentadienyl compound of zirconium and/or
an alkyl-substituted cyclopentadienyl compound of hafnium is used
as the transition metal compound, and a condensation product of an
organoaluminium compound and water is used as the organometallic
compound. ~ :
The transition metal compound may be represented by the
formula :
(R5C5)m M X4_m (I)
:, ; , -
wherein R represents a C1-C20 alkyl group, R5C5 represents a
cyclopentadienyl group substituted with an alkyl group, M ~ -
represents a zirconium or hafnium atom, X represents a hydrogen or
halogen atom, or a C1-C20 alkyl group, and m represents an integer :~
from 2 to 4.
The organometallic compound is exemplified by
methylaluminoxane, ethylaluminoxane, propylaluminoxane, :~
isopropylaluminoxane, butylaluminoxane, isobutylaluminoxane and :-
amylaluminoxane.
.:"::
. . . . .
:, . : -
,.~i,
:....
- ` 2116070 ~:
- 2 -
In Table 1 on Page 8 of EP-A-268 214, the results are shown of
a comparative experiment (Comparative Example 1) in which the
catalyst used contained an _ substituted cyclopentadienyl zirconium
compound, i.e. bis(cyclopentadienyl)zirconium dichloride, as the
transition metal compound and methylaluminoxane as the
organometallic compound. It will be seen from Table 1 that a
polymerisation degree of 41.9 was obtained using this catalyst.
Although no data is given on the selectivity of the catalyst with
respect to vinyl and vinylidene end-groups (in contrast to the
catalysts of Examples 1 to 18 which contained a transition metal
compound of formula I above), it is stated in the text at Page 7,
lines 6 to 8 that in the comparative examples, polymerisation
reaction took place preferentially to oligomerisation reaction and
product were all high polymers which predominantly had vinylidene
group as terminal unsaturated group. -
There is no further structural information provided in
EP-A-268 214 on the comparison products.
However, in Examples 1 to 4 of EP-A-490 454, atactic propylene -
oligomers having number average molecular weights 1070, 1455, 1710
and 2130 and thus polymerisation degrees respectively of 25.5,
34.6, 40.7 and 50.7, were prepared according to methods analogous
to that disclosed in Comparative Example 1 of EP-A-268 214, but
using a higher molar ratio of methylaluminoxane to bis(cyclopenta- -~
dienyl)zirconium dichloride. The molecular structures of the
oligomers were investigated by C nuclear magnetic resonance
spectroscopy and were found to be substantially of the formula,
CH3 CH3
( 2 n 2
with at least 95~ of polymer chains containing a vinylidene
end-group.
In EP-A-69 951, a process is disclosed for the preparation of
a polyolefin by polymerising an olefin of the formula CH2CHR in
which R is hydrogen or C1-C10 alkyl, on its own or as a mixture, if
2 ~ 7 a
-- 3
appropriate as a mixture with C4-C12 alpha, omega diolefins, in
solvents, liquid monomers or the gas phase, at temperatures between
-50 and 200C, using a soluble, halogen-containing transition metal
compound and aluminoxanes, which comprises carrying out the
polymerisation in the presence of a catalyst system composed of the
following components:
a) a transition metal compound of the general formula
(Cyclopentadienyl)2 Me R Hal
in which R i9 a cyclopentadienyl or Cl-C6 alkyl group, or a halogen
atom, especially chlorine, Me is a transition metal, especially
zirconium, and Hal is a halogen atom, especially chlorine,
b) an aluminium compound of the aluminoxane type having the
general formulae : :
Al2OR4~Al(R) )n
for a linear aluminoxane, and ;~
(Al(R)~)n+2
for a cyclic aluminoxane, in which n is an integer from 4 to 20,
and R is a methyl or ethyl group, preferably a methyl group. ::
Preferred catalyst systems are those consisting of bis(cyclo- - ~:~
pentadienyl)zirconium dichloride or bis(cyclopentadienyl)zirconium
monomethylmonochloride and methylaluminoxane. :
The catalyst system of EP-A-69 951 is said to be advantageous
when compared to halogen-free catalyst systems in that a higher
polymerisation activity is observed at useful polymerisation
temperatures between 40 and 80C. It is also stated to be
advantageous compared to other halogen-containing catalyst systems,
e.g. Ziegler catalysts, in that it contains proportionately less
halogen resulting in, not only the formation of polyolefins having
a lower halogen content (which is beneficial from an environmental
standpoint), but also less corrosion of the reactor.
._ . - ~ -
.',~- . .:
:: : . :
... : ~ :
,;
.i. :. :
.
211~7~
-- 4
In the examples of EP-A-69 951, the preparation of polymers
from ethylene (Examples 1, 2 and 3), propylene (Example 4),
1-hexene (Example 6) and mixtures of ethylene with 1-butene
(Example 5) or with 1-hexene (Example 7) are described. The number
average molecular weights of the polymers obtained, where given,
`are generally high. Indeed, the ethylene polymers of Examples 1
and 2 had number average molecular weights respectively of 91,000
and 1,OOO,ooo, and the propylene polymer of Example 4 had number
average molecular weight of 5,000.
Although it is stated in the text at Page 3, lines 31 and 32
that the transition metal and aluminium are used in an atomic ratio
of lO:1 to 10 :1, it is clear from the examples of the
specification that this statement is incorrect. For example, if
reference is made to Example 6 describing the preparation of the
1-hexene polymer, it will be seen that the catalyst system
compri~ed 130 mg methylaluminoxane (corresponding to 2.2 mmol
aluminium) and 6.66 x lO mol bis(cyclopentadienyl)zirconium
dichloride (corresponding to 6.66 x 10 mmol zirconium).
Therefore, the atomic ratio of zirconium to aluminium was 6.66 x
10 4: 2.2, or approximately 1 : 3303.
There is no teaching anywhere in EP-A-69 951 of the detailed
molecular structures of the polymers obtained and, furthermore, no
suggestion therein that polymers derived from higher olefins, i.e.
those containing 6 or more carbon atoms, would or should have
similar structures to those derived from lower olefins such as
propylene.
In W0 89/12662 it is disclosed that a characteristic of the
molecular structures of 1-alkene oligomers that has been found to
correlate very well with improved lubricant properties in
commercial lubricants is the ratio of methyl to methylene groups
(branch ratio) in the oligomer. In particular, viscosity index
(VI) has been found to increase with lower branch ratio.
W0 89/12662 describes liquid lubricant compositions and a
process for their preparation, which comprise C30-C1300
hydrocarbons, the compositions having a (low) branch ratio of less
- 2116070
-- 5
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 -15C.
The liquid lubricant compositions are prepared by a process
which comprises oligomerising an olefin containing from 2 to about
20 carbon atoms, preferably an alpha-olefin, e.g. a C7-C16,
preferably C8-C14, alpha-olefin, under oligomerisation conditions
in contact with a supported and reduced valence state metal oxide
catalyst from Group VI B of the IUPAC Periodic Table, preferably
chromium oxide. The process is carried out at a temperature of 90 ;~
to 250C in order to produce oligomers having molecular weights
within the above-specified ranges. This temperature range is
stated (Page 18, line 32 to Page 19, line 1) to be higher than the
temperature suitable to produce high molecular weight
polyalpha^olefins.
At Page 12, line 27 to Page 13, line 1 of WO 89/12662, it is
stated that, in general, the novel oligomers have a regular
head-to-tail structure:
-(CH2-CH)x-
(I 2)n
3 -~ -
where n is 3 to 17, with some head-to-head connections.
It has now surprisingly been found that by using certain Group :~
IV A catalyst compositions, it is possible to prepare liquid ~ ~ -
organic compounds from higher olefins in good yield that have a low
polymerisation degree and that also have very highly regular
head-to-tail structure, which are suitable as base
materials for lubricants.
The invention may be defined as relating to a process for the
preparation of liquid organic compounds suitable as base materials
for lubricants, comprising contacting one or more alpha-olefins
containing 8 to 20, preferably 8 to 18, more preferably 8 to 16,
still more preferably 8 to 14, and especially 8 to 12, carbon atoms
, ~ , . ' ~ . ' . ' - .' ' ' ' ' '
~5
211&~7~
- 6 -
per molecule, under oligomerisation conditions with a catalyst
composition based on
a) a Group IV A metal compound of the general formula (CP)2 MeX2,
wherein Cp represents a cyclopentadienyl group, Me represents
a Group IV A metal and each X independently represents a
moiety selected from the group consisting of hydrocarbyl
groups, hydrocarboxy groups, hydrocarbamido groups, each of
which may be optionally substituted, hydrogen atoms and
halogen atoms and
b) a substantially non-coordinating anion source;
and optionally subjecting the oligomers formed to an addition
reaction to reduce their olefinic unsaturation.
In order to minimize the number of branching groups in the
molecules of the oligomeric products, it is preferred to use
substantially linear alpha-olefins as starting materials.
Linear alpha-olefins with 8 to 20 carbon atoms per molecule
are readily available from processes for the oligomerisation of
ethene according to the "Aufbau" -principle. It may be feasible to
select the ethene-oligomerisation conditions such that
predominantly products within the desired range of 8 to 20 carbon
atoms per molecule are formed. However, in most existing ethene-
oligomerisation processes a wide range of olefins is formed, viz.
olefins having from 4 to 30 carbon atoms per molecule. By
conventional separation techniques, such as fractional
distillation, olefins within the desired range of 8 to 20 and
preferably within the range of 8 to 14 carbon atoms per molecule
can easily be recovered.
A convenient process for the catalytic oligomerisation of
ethene is described in US Patent No.3647915.
In the process of the invention the alpha-olefins containing 8
to 20, and preferably 8 to 14 carbon atoms per molecule are
converted to products, typically having a number-average molecular
weight in the range of 400 to 3000, preferably in the range of 400
to 1000 and most preferably in the range of 400 to 700.
211~070
-- 7 --
Products having higher molecular weights, e.g. number-average
molecular weights of 6000 or more, generally are less suitable as
base materials for lubricants and hence the oligomerisation
conditions are preferably selected such that the molecules of the
obtained product are predominantly derived from 2 to 8 monomeric
units. For certain applications, dimers are suitable which are, ~ -
preferably, derived from monomers having carbon numbers in the
higher region of the above mentioned carbon range.
In the Group IV A metal compounds participating in the
catalyst compositions of the invention, the Group IV A metal is
preferably zirconium or hafnium. Zirconium compounds are in
particular preferred. ~;~
In the present specification and claims, the Group IV A metal
compounds are represented by the general formula (CP)2 MeX2. In the
compounds of this formula the Group IV A metal (Me) is linked to
two cyclopentadienyl groups (Cp) and to two moieties X which may be ~ -
the same or different and are selected from optionally substituted
hydrocarbyl, hydrocarboxy and hydrocarbamido groups, hydrogen atoms
and halogen atoms, e.g. bromine, and preferably chlorine, atoms. ~- -
Examples of hydrocarbyl groups include alkyl, aralkyl,
cycloalkyl, aryl and alkaryl groups. In this specification, unless
otherwise stated, an alkyl group or an alkyl moiety in an aralkyl
or alkaryl group may be linear or branched and preferably contains
up to 20, more preferably up to 12 and especially up to 10 carbon
atoms. Particularly preferred alkyl groups are methyl, ethyl,
propyl, hexyl and nonyl groups. An aryl group may be any aromatic
group, especially a phenyl or naphthyl group. An aralkyl group is
an alkyl group substituted by an aryl group, such as a phenylmethyl
or phenylethyl group. An alkaryl group is an aryl group
substituted by one or more, preferably one to two, alkyl groups. A
cycloalkyl group may contain from 3 to 8, preferably 3 to 6, carbon
atoms, e.g. a cyclopentyl or cyclohexyl group.
Examples of hydrocarboxy groups include alkoxy groups,
preferably Cl-C20, more preferably Cl-C10, alkoxy groups such as
. .
,, '
~ .
-
, . .
211S~73
-- 8
methoxy, ethoxy and butoxy groups, and aryloxy groups, e.g. a
phenoxy group.
Examples of hydrocarbamido groups include acetamido and
propionomido groups.
If desired, the hydrocarbyl, hydrocarboxy and hydrocarbamido
groups may each be optionally substituted by one or more,
preferably one or two, substituents selected from halogen atoms
(e.g. chlorine atoms), nitro, hydroxyl, cycloalkyl, alkoxy,
haloalkoxy, amino, dialkylamino, formyl, alkoxycarbonyl, carboxyl,
alkanoyl, alkylthio, alkylsulphinyl, alkylsulphonyl, carbamoyl,
alkylamido, aryl, alkaryl and heterocyclyl group~. When any of the
foregoing substituents contain an alkyl moiety, this may be linear
or branched and may contain up to 12, preferably up to 6, and
especially up to 4, carbon atoms. A heterocyclyl group may be any
saturated or unsaturated ring system, e.g. a C5-C7 ring system,
containing at least one heteroatom selected from oxygen, nitrogen
and sulphur, 5- and 6- membered rings being especially preferred,
e.g. a tetrahydrofuranyl, furanyl, piperidinyl, pyridinyl,
tetrahydrothiophenyl or thiophenyl (thienyl) group.
However, for practical reasons, the preparation of compounds
of formula (Cp)2MeX2 wherein each X independently represents a
moiety selected from the group consisting of unsubstituted
hydrocarbyl groups, unsubstituted hydrocarboxy groups,
unsubstituted hydrocarbamido groups, hydrogen atoms and halogen
atoms, is preferred.
Preferably, each X independently represents a hydrocarbyl
group, a hydrocarboxy group, e.g. a lower alkoxy group such as a
methoxy or ethoxy group, or a halogen atom.
More preferably, each X independently represents a hydrocarbyl
group, e.g. an alkyl group such as a C1-C4 alkyl group, or a
halogen atom, e.g. chlorine atom.
Compounds of formula (Cp)2MeX2 in which each X independently
represents a methyl group or a chlorine atom are particularly ..
preferred.
2116~70 ~ ~
g .: :
The Group IV A metal compounds can be prepared by methods
known per se. For example, bis(cyclopentadienyl) zirconium
dichloride may be prepared by reaction of cyclopentadienyl lithium
with zirconium tetrachloride and by subsequent reaction with methyl
lithium, bis(cyclopentadienyl) zirconium dimethyl may be obtained.
The catalyst compositions used in the process oi the invention
are further based on a source of substantially non-coordinating
anions, i.e. a source of anions which do not, or only to a minor ~
extent, coordinate with the Group IV A metal atom. Examples of :
substantially non-coordinating anion sources include sources of
carborane anions, such as BllCl2~l2 anions and aluminoxanes.
Aluminoxanes are preferred anion sources.
Aluminoxanes are well known polymeric aluminium compounds
which can be represented by the general formulae (R-Al-0) , which
represents a cyclic compound, and R(R-Al-0) -AlR2, which represents
a linear compound. More complicated structures may exist as well.
In these general formulae R represents an alkyl group, preferably
having in the range of from l to 5 carbon atoms, such as methyl,
ethyl, iso-butyl or iso-propyl and q is an integer of from l to
lO0, especially q is in the range of from 5 to 20. Also very
effective is a mixture of methyl and isobutyl aluminoxane. Most
preferably R is methyl, so that preferably the aluminoxane
comprises a methylaluminoxane. The aluminoxanes are suitably
prepared by reacting water with trialkylaluminium compounds by
methods known in the art. A mixture of linear and cyclic compounds
is usually obtained.
The molar ratio of the aluminoxane to the Group IV A metal
compound may vary between wide ranges. Conveniently, the molar
ratio of the aluminoxane to the Group IV A metal compound is within
the range of from 50:1 to 2000:1, preferably from 300:1 to lOOO:l,
calculated as gram atom aluminium per gram atom of Group IV A
metal.
The catalyst composition of the present invention may be
prepared from the Group IV A metal compound and the anion source
prior to the contacting with the alpha-olefin(s) to be oligomerised
.. , : . :: : :: :
:. - . : . ,
, ~ . ~ - .
- -` 2116070
- 10 -
or they may be prepared in situ, i.e. in the presence of the
alpha-olefins. It i8 preferred to prepare the catalyst composition
by mixing together the two components in solution in a solvent such
as toluene to form a liquid catalyst system.
The amount of catalyst composition, used in the process of the
invention is usually selected such that per mole of alpha-olefin to
be oligomerised, from 10 to 10 gram atom of Group IV A metal is
supplied.
The oligomerisation reaction is conveniently carried out at a
temperature in the range of 0 to 100 C, preferably in the range of
10 to 60 C. Most preferably, a reaction temperature in the range
of 20 to 45 C is selected.
Although not strictly necessary, the process of the invention
is preferably carried out in the presence of an inert liquid
diluent. Suitably a diluent is selected which can also be used as
the solvent for the catalyst composition.
Examples of suitable diluents are alkylbenzenes, such as
toluene, chlorinated hydrocarbons, such as dichloromethane and
dichloroethane.
The process can be carried out in batch or in continuous
operation.
Preferably, the oligomerisation reaction is performed in the
substantial absence of air or moisture.
As explained above, suitable base materials for lubricants
have to fulfil certain requirements, in particular as regards their - .
structure, such as degree of branching, and their molecular weight.
A further requirement is the substantial absence of olefinic
unsaturation in potential lubricant components. Olefinic
unsaturation is especially undesirable in compounds of relatively
low molecular weight, as the stability of these compounds under
oxidative conditions is usually limited. The presence of
significant olefinic unsaturation in the molecules of compounds
intended for use in lubricant compositions, would result in the
formation of decomposition products during use, by oxidation of
t~
2116070
.
double bonds, which would be at the expen3e of the lubricating
properties of the compositions.
Hence, it is preferred to substantially remove any olefinic
unsaturation in the compounds prepared according to the invention,
before they are used as components for lubricants. This is
effected by subjecting the oligomers formed to an addition
reaction.
A convenient method for achieving this, comprises addition of
hydrogen by subjecting the oligomeric product to a hydrogenation
treatment. Suitably the hydrogenation treatment is performed
catalytically, in particular in the presence of conventional
catalysts, such as nickel -, platinum- or palladium-containing
catalysts.
In principle, the saturation of double bonds in the oligomeric
molecules may be achieved in situ, viz. by adding hydrogen to the
rçaction mixture during the oligomerisation reaction. The supply of
larger or smaller quantitites of hydrogen to the mixture also
allows a control of the molecular weight of the formed oligomeric
products. However, as the presence of hydrogen during the
oligomerisation reaction would result in the hydrogenation of
otherwise interesting unsaturated lower-boiling by-products, it is
preferred to perform the hydrogenation in a separate step, sub-
sequent to the oligomerisation reaction. ~ ;
Other methods for substantially removing olefinic unsaturation
from the oligomeric products, involve addition reactions wherein
functional groups are introduced in the oligomeric compounds in one -
or more reaction 3teps, following the oligomerisation reaction. In
this manner, in addition to saturating olefinic double bonds, the
introduction of selected functional groups can improve the
properties of the compounds, required for their use in lubricants.
For example, in a functionalisation step, following the
oligomerisation reaction, a thiol may be added to the double bond
of an oligomer, thus introducing a mercapto group in the molecule.
Epoxy groups may be introduced by reaction with hydrogen peroxide,
or a substituted phenyl group by reaction with a substituted
: :
'"";-''
.~ .
;~'.. ' ' ' ' ' ' - , ':
7~
' '
,i,.. .
~ ~,
-:" 2116070
- 12 -
benzene. Furthermore, ester groups may be introduced by radical
reaction with thioglycolic acid in the presence, e.g. o lauryl
peroxide, followed by reaction with an alcohol, e.g. hexanol or
2-ethylhexanol.
Preferred functional groups are succinic acid, succinic acid
ester and succinimide groups. Such groups may conveniently be
introduced by reacting the oligomeric product with maleic anhydride
and, optionally, in a second functionalisation step, with an
alcohol or amine, e.g. a polyamine.
Preferably, the number of functional groups, introduced per
molecule of oligomer product is in the range from 0.7 to 1. Any
remaining unsaturation may be removed by a hydrogenation treatment,
as indicated above.
The liquid organic compounds prepared according to the
invention, which compounds may contain functional groups and from
which any olefinic unsaturation has been substantially removed, are
eminently suitable as participants in lubricating compositions, but
also as dispersant luboil components or additives. These
compositions generally comprise a major amount of a lubricating oil
and a minor amount of one or more additives such as dispersant
additives, detergents, VI improvers, anti-oxidants and friction- ~ ~
reducing agents. :
The invention will be further understood from the following
illustrative examples.
Example 1
a) Oligomerisation of olefins
In an inert atmosphere a solution of 7.S g of commercially
available methylaluminoxane, dissolved in 80 mL of toluene was
introduced in a 3-L reaction vessel equipped with a mechanical
stirrer. To this solution wa~ added 600 mL of dry toluene, 360 mL
(274 g) of dry technical l-dodecene, having a l-dodecene content of
~92% m/m and consisting of the compounds mentioned in Table 1, and
250 mL (180 g) of dry technical 1-octene, having a 1-octene content
of ~9S.S% m/m and consisting of the compounds mentioned in Table 2. -~
-' ':, ~ . . , ~, : .
2116070
- 13 -
In an inert atmosphere the temperature of the mixture was raised to
30C. An amount of 75 mg of commercially available
bis(cyclopentadienyl)zirconium dichloride was dis~olved in 10 mL of
dry toluene and subsequently the solution was added to the reactor.
The reaction temperature was maintained at 30C. After stirring for
20 hours the reaction mixture was treated at 30C with 60 mL of
water during 1 hour under stirring. After cooling to room
temperature the mixture was extracted with 200 mL of a 5% m/m
sodium chloride (NaCl) solution in water. The oligomer solution in
toluene was separated from the aqueous layer. The aqueous layer was
extracted three times with 100 mL of toluene. The toluene extracts
were combined and subsequently washed with 200 mL of 5% m/m aqueous
sodium chloride (NaCl). The toluene solution was separated and was
subsequently dried over anhydrous magnesium sulphate (MgS04). The
toluene and the unconverted olefins were evaporated at 0.04 mbar
(4 Pa) at 110C. The amount of remaining oligomers was 390 g.
According to gas liquid chromatography (GLC), the conversion
of 1-olefins was greater than 90~.
The molecular structure of the oligomerisation product was
investigated by H-NMR and C-NMR spectroscopy. The C-NMR
spectrum showed the presence of two sets of two types of
unsaturated carbon atoms, viz. = CH2 (delta = 109.8, 109.9 ppm for
the oligomers; delta = 108.1 ppm for dimer) and -CR= (delta = 147.8
ppm for the oligomers; delta = 148.8 ppm for dimer), thus ~ :
indicating terminal vinylidene groups of the formula -CR=CH2 for
both the oligomers and the minor amount of dimer (~8% m/m) present
in the oligomerisation product. From this spectrum, it could be ~ ~-
deduced that at least 95% of the product possessed a vinylidene
end-group. This was confirmed by H-NMR. The C-NMR spectrum
showed reasonably well defined peaks for the CH3, CH2 and CH carbon
atoms along the chain. Thus, the oligomers were all substantially
of the formula
R' R'
2 C (CH2 - CH)n - H
. :
,~ , ', . . . .
- 2116070
- 14 -
wherein each R' = C6H or C H
The oligomers were introduced into a fractionating column, in
order to remove the dimers having less than 24 carbon atoms as well
as any lower boiling compounds. The amount of oligomers, recovered
as bottom fraction was 279 g.
The number-average molecular weight was 560.
Table 1: Composition of technical 1-dodecene
,
Carbon distribution, ~ m/m:
C10 and less <1
C12 >97
C14 and greater c2
Hydrocarbon type, ~ m/m:
Total n-alpha olefins >94
C12 alpha olefin >92
Branched plus internal olefins <6
Paraffins ~0.2
Table 2: Composition of technical 1-octene ~ :
Carbon distribution, ~ m/m:
C6 and less <0.5
CB
C10 and greater ~0.5
Hydrocarbon type, ~ m/m: ~-
Total n-alpha olefins >96.5
C8 alpha olefin>95.5
Branched plus internal olefins ~3.5
Paraffins ~0.1
; ~ -: - :
-` 211~70
- 15 -
b) Hvdrogenation of oliqomers
A 500-mL Hastelloy autoclave equipped with a mechanical
stirrer, was charged with 80 g of olefin oligomers, prepared
according to Example la) and 75 mL of 1,4-dioxane. An amount of 16
g of a finely divided catalyst, comprising 5~ m/m palladium on a
charcoal support was added. The autoclave was pressurized with H2
to 60 bar (6 MPa) and under stirring the temperature was raised to
150C. During this heating-up period, which took about 2 hours,
>95~ of the theoretical amount of hydrogen was consumed. After the
reaction mixture had been stirred at 150C for another 14 hours, it
was cooled to room temperature and was subsequently filtered. The
catalyst was washed with 75 mL of 1,4-dioxane and subsequently the
volatiles of the combined filtrate were removed in a rotary
evaporator at c5mbar (c500 Pa) at 110C. The yield of hydrogenated
oligomers was 76 g.
As shown by ozone titration, and by H- and C-NM
spectroscopy the product did not exhibit any significant
unsaturation (less than 0.4~).
Samples of the oligomeric product were taken and an evaluation
was made of the following physical and performance characteristics~
Kinematic viscosity (using ASTM D445);
Viscosity index (using ASTM D2270);
Pour point (using ASTM D97); ~ :~
Oxidation stability (using DSC, as indicated below~
Volatility (using thermogravimetric method TGA-IP 393/91).
Molecular weight distribution, defined as the ratio of weight
average molecular weight (Mw) to number average molecular weight
(Mn) (MW/Mn~
Branch ratio, defined as in WO 89/12662 as the ratio of wt.
fraction of methyl group (z) to 1-(wt. fraction of methyl group),
i.e. 1-Z, (Z/1-Z) (determined by 13C-NMR).
The evaluation results are shown in Table 3.
- : .. ~ : ' .
.: . :
2116070
- 16 - -
______________________________________ _______ ___ ______ ________
Differential Scanning Calorimetry (DSC)
DSC monitors the differential power supplied to a pair of heaters
as a function of time or temperature, as the sample and a suitable
reference material are subjected to the following temperature
programme: Initial test temperature 40 C, final temperature 350
C. Heating rate 20 C/minute. DSC cell atmosphere of 15 psi (103.4
kPa) gauge pressure of oxygen. Purge flow rate of 60i 10 mL/min.
During the sample run, the control software processes the
signals such that they represent the differential heat flow between
the sample and the reference material.
Since oxidation of lubricating oils is generally exothermic,
DSC is used to detect the heat evolved during oxidation.
Measurements are made with 2.0 ~ 0.05 mg samples in a prepared open
aluminium pan, an identical empty pan being used as reference.
Extrapolated onset temperatures are determined and given as the
nearest whole number (C) ;~
_ _ _ _ _ _ _ _ _ _ _ _ . :
~ Molecular Weight Distribution (MWD) ; ~ ;
MWD was determined by high temperature - programmed (35-440C) gas
chromatography, using a flame ionisation detector at 450C (carrier
gas: helium; 10 mL/min). The analysis was carried out by on-column
injection (injector temp.: 25C; sample: 1 microlitre of 1/1000
solution in carbon tetrachloride) on a 6AQ5/HT5 (siloxane-carborane
copolymer) capillary column (6 m x 0.53 mm; film thickness: 0.10
micrometre) purchased from Scientific Glass Engineering Inc., USA
(catalogue number 051580).
____________ ______ _____ ____ _________ ___ _ _ ____ _______
ExamPle 2
a) Oligomerisation of olefins
Similarly to Example la) an oligomerisation was carried out
using 50 mL of an equimolar mixture of technical l-dodecene, having
the composition mentioned in Table 1 and technical 1-octene, having
the composition mentioned in Table 2. The resulting oligomer was
21~6~7~
- 17 -
worked-up along the lines mentioned in Example la), with the
difference that no fractionation was carried out to remove the
dimers having less than 24 carbon atoms. Analysis by H- and
C-NMR spectroscopy showed that ~95~ of the end-groups of the
oligomers were vinylidene groups. According to GLC, the conver~ion
of 1-olefins was greater than 90~.
The number-average molecular weight was 500.
b) HYdrogenation_of oligomers
The oligomers prepared according ~o Example 2a) were
hydrogenated in a similar manner as described in Example lb). As
shown by ozone titration and by H- and C-NMR spectroscopy the
remaining unsaturation of the hydrogenated product was less than
1 ~. :
An evaluation of performance properties of the product was
made as indicated in Example lb). The evaluation results are shown
in Table 3.
Example 3
a) Oligomerisation of olefins
Along the lines of Example 2a) 50 mL of technical 1-octene,
having the composition mentioned in Table 2, was oligomerised.
Analysis by 1H- and 13C-NMR spectroscopy showed that >95% of the
end-groups of the oligomers were vinylidene groups. According to
GLC, the conversion of 1-octene was greater than 90~.
The number-average molecular weight was 450.
b) Hydrogenation of oligomers
The oligomers prepared according to Example 3a) were hydro-
genated in a similar manner as described in Example lb). As shown
by ozone titration and by H- and C-NMR spectroscopy the
remaining unsaturation of the hydrogenated product was less than
1 ~.
. : - - . - : .
.x
~', ',~,' ' ' '' '' ' ,' ' ~ , '
2 ~ a
- 18 -
An evaluation of performance properties of the product was
made as indicated in Example lb). The evaluation results are shown
in Table 3.
Example 4
a) Oligomerisation of olefins
Along the lines of Example 2a) 50 mL of technical l-dodecene,
having the compoqition mentioned in Table 1, was oligomerised.
Analysis by lH- and 13C-NMR spectroscopy showed that ~95~ of the -
end-groups of the oligomers were vinylidene groups. According to
GLC, the conversion of l-dodecene was greater than 90
The number-average molecular weight was 650.
b) Hvdrogenation of oligomers
The oligomers prepared according to Example 4a) were
hydrogenated in a similar manner as described in Example lb). As
shown by ozone titration and by H- and C-NMR spectroscopy the
remaining unsaturation of the hydrogenated product was less than
1~.
An evaluation of performance properties of the product was
made as indicated in Example lb). The evaluation results are shown
in Table 3.
Comparative Examples A and B (not according to the invention)
The physical and performance characteristics of two commercial
products were evaluated in the manner, as indicated in Example lb).
The commercial samples were:
A. Mobil SHF 61 (hydrogenated poly alpha olefins);
B. XHVI 5 (Trade mark).
The evaluation results are shown in Table 3.
~' . ,
211607~
- 19 -
Table 3
Ex M w/ Branch k~ VI 9~gr DSC onset TGA loss
M ratio mm /s pt (oxid. up to 262C
stab.) (volatility)
__
1 560 1.2 0.16 6.53 157 -39 213 9.5
2 500 1.4 0.17 5.93 177 -54 208 ~27
3 450 1.7 0.22 6.72 166 -57 201 >28
4 650 1.5 0.14 6.32 202 -27 209 19
A _ 0.24 5.63 136 -62 210 10
B _ 0.23 5.49 153 -18 206 ll.9
As can be seen from the evaluation results the hydrogenated
oligomers according to the invention exhibit excellent viscosity
index values. As regards oxidation stability they are on a par with
the commercial products. Their pour points are consistent with
those of product A and significantly better than those of product
B. If for certain applications the volatility is of particular
importance, this requirement can easily be met, as shown by
Example 1.
' ~ ., . .' ' ' ' . ' i:
