Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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This application is a di.vis;on of appending appli.cation
N0. 304,610 fi.led on June 1, 1978.
This invention relates to a method for the removal
unsaturations from oligomers prepared from alpha-olefines coming
from the several distillation cuts of the crack.ing products of
higher hydrocarbons.
It is known that the paraffin oils have found in recent .
times a wide number of applications in the food industry, in the
pharmaceutical industry, in agriculture, as diluents for pest-
control agents, rubber extenders, plasticizers and lubricantoils.
They generally obtained by refining appropriate.
fractions of crude oil but the situation which has arisen
recently as to the shortage in crude supplies and the considerable
price chalk up have originated a number of difficulties in the
production of paraffin oils.
An alternative route towards the obtention of oils is the
cationic oligomerization of the alpha olefines which contain,
predominantly, from 3 to 6 carbon atoms, said oligomerization
being conducive to oily products having a low mol wt and con-
taining residual unsaturation in the chain: these latter can be
removed by a hydrogenation process which gives a saturated
product .
However, the conventional methods which are prevailingly
based on the use of Friedel Crafts halides, are effected by a
few considerable shortcomings, such as low reaction yieldc., dif-
ficulties in the control of the reaction conditions and thus an
uneasy performance of the reaction.
A new method has now been disclosed in the parent
application No. 304,610 for the preparation of oligomers from
alpha-olefines using a very specific catalyst system. This new
method has the advantage, over the conventional procedures, of
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giving higher polymer yelds, while being easier to carry out.
In this new method, the reaction is also more easily
controllable and the reaction system is, moreoVer, wholl~
homogeneous.
The very specific catalytic system used in the method
disclosed in the parent application, makes it possible to
prepare oligomers from alpha-olefines having a number of carbon
atoms of from 3 to 12 and especially oligomers of propylene,
butene-l, pentene-l and hexene-l.
The catalytic system in question is composed by two
components, selected from among the following classes of
compounds :
(a) - an organic metallic compound of aluminium, as represented
by the following general formula :
RmAlX3-m
wherein X is a halogen atom, R is hydrogen or a monovalent redical
selected from the group consisting of alkyl, aryl, cycloalkyl,
aralkyl, alkaryl, alcoxyl and ester radicalshaving from 1 to 12
carbon atoms, and m is a number comprised between 1 and 3.
Examples of such compounds are: AlEtC12, AlEt2Cl, AlEtl 5
Cll 5 and others.
(b) _ a compound capable of reacting with the compounds of the
class (a) above to give the catalytic species capable of initia-
ting polymerization, and having the formula HX, wherein X is a
halogen.
Examples o~ the latter compounds are : HCl. Hbr, HF r HI .
The reaction is carried out in a homogeneous phase and
with a solvent means being present which is selected, as a rule,
among the hydrocarbons or halogen-substituted hydrocarbons having
a number of carbon atoms of from 3 to 12. It is possible, never-
theless, to operate with no solvent being present, the solvent
phase being in such a case the excess of the monomer. The two
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components of the catalytic system can be introduced in the
reaction medium either simultaneously or separately and the
order of addition has no significant bearing on the catalytic
species which can be obtained.
The molar ratio of the component (a) to the component
(b) may be comprised be~ween 0.1 and 5, the preferred range
being from 0.5 to 3.
The reaction is conducted at a temperature comprised
between -30C and +100C, the preferred range being from -10C
to +80C.
The products which are obtained from the polymerization
have a numeric average mol wt of from 200 to 3000 and contain
residual unsaturations which can be expressed in terms of
bromine number ~i.e. grams of Br absorbed by 100 g of polymer),
which is determined according to several methods, such as ASTM
D 1159.
It is the object of the present invention to provide
a method for either reducing or completely removing the
unsaturations which are left on completion of the oligomeri2ation.
This method consists m hydrogenating the unsaturated
oligomer at a temperature comprised between 150C and 300C,
under partial hydrogen pressures comprised between 20 atm and
150 atm, in the presence of hydrogenation catalyst such as Ni
on kieselguhr, Ni-Raney, Pd on charcoal, Pt on charcoal.
Possible trace residues of unsaturated products (the
Br number of the treated product being below 0.1) can eventually
be removed by having the compounds flowing through adsorbing
siliceous earths at a temperature comprised between 50C and
100C, to give the desired saturated products.
The foregoing and the operational details will become
more clearly apparent from the ensuing illustrative examples
which are not to be construed as limitations to this invention.
E X A M P L E
,
A 10~ ml steel autoclave hav;ng a magnetic st;rrer and
a thermometer well, and whi.ch has previously been dried in a
vacuum, is charged, by siphoning thereinto a solution containing
1.5 millimol of anhydrous HCl diluted in 1 ml of nor.pentane and
14 g of a C4 hydrocarbon cut having the following composition :
Propane 1.22%
Propylene 0.29%
Isobutane 3.68%
Nor.butane 17.08%
Butene-l 61.64~
Butene-2-trans 10.30%
Butene-2-cis 2.15~
Isobutene 3.64%
The temperature is stabilized on + 20 C, whereafter
there is introduced, by nitrogen overpressure, a solution
containing 1.5 millimol of AlEtC12 diluted in 10 mls of nor.
pentane (Molar ratio of HCl to AlEtC12 = 1.0).
A temperature rise up to 28C is experi.enced. The
reaction is continued for 30 mins and is then discontinued by
addition of methanol.
The unreacted monomers are flashed and the resultant
product is washed with water supplemented with NaOH to remove
the traces of the catalyst, and subsequently with distilled
water until neutrality is attained.
The hydrocarbonaceous phase is then evaporated to
dryness to remove the solvent completely. There are obtained
7.85 g of dry oligomer (yeld 85.9~ calculated with respect to
butene-l and i.sobutene which are present), which has an average
osmometric mol wt, Mn of 592 and a contents of unsaturations,
expressed in terms of Br number, of 38.5 as determi~ed according
to the method ASTM D 1159, and a contents of residual C12 of
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1144 ppm ~parts per million) as determined with an X-ray fluo-
rescence apparatus. Simultaneously, with the same procedl~re,
a sample procedure, a sample test has been carried out by
introducing in the autoclave the same quantities of C4 hydro-
carbon fraction and introducing then 1.5 millimol of AlEtC12.
A temperature increase of 1.5 C (from +21 C to 22.5 C) has
been noted and, after discontinuation of the reaction there
have been obtained 0.35 g (yield 4.0~) of polymer on which it
has not been possible to determine any property.
The product obtained by using the catalytic system
AlEtC12 plus HCl has been subjected to hydrogenation in order
to remove the unsaturations present in the polymeric chain by
following the procedure indicated hereinafter: an autoclave
having a mechanical stirrer and thermometer well is charged
with 5.0 g of product and 0.34 g of Ni Raney prepared according
to the indications reported in A.I. Vogel, Practical Organic
Chemistry, Longmans, Green & Co. Edit page 870 (1956). The
temperature is brought to 270C with a hydrogen pressure of
90 atm for a time of 20 hrs. Upon cool~ng, the autoclave is
discharged and, on the hydrogenated product, the residual
unsaturations are determined and a bromine number of 0.15 is
obtained.
E X A M P L E 2
With the same procedure as in Example 1, the autoclave
is charged with 1.27 millimol of anhydrous HCl diluted in 1 ml
of nor.pentane and 14 g of a C4 fraction having the same
composition as reported in Example 1.
The reaction is started at the temperature of +20 C
with the addition of a solution containing 1.5 mïllimol of
AlEtC12 diluted in 10 mls of nor.pentane (molar ratio of HC1
to AlEtC12 = 0.85).
A temperature increase up to 27 C is noted and the
reaction is continued for 30 mins. There are obtained 7.70 g
of dry product (yield 84.2%) which has an average osmometric mol
wt Mn of 643, a Br number of 34.3 and a contents of C12 (residual)
of 1262 ppm.
Hydrogenation has been carried out on this product
according to the procedure a set forth in Example l, the residual
unsaturations being subsequently on the hydrogenated product.
A value of 0.20 has been obtained for the bromine number.
E X A M P L E 3
With the same procedure as in example 1 the autoclave
has been charged with 0.7S millimol of anhydrous HCl diluted in ,
1 ml of nor.pentane and 14 g of a C4 fraction having the same
composition reported in Example l.
The reaction is started at a temperature of ~120C by
the addition of a solution containing 1.5 millimol of AlEtC12
diluted in 10 mls of nor.pentane (Molar ration of HCl to AlEtC12=
0.5)-
A temperature increase to as much as 26C is noted and
the reaction is continued during 30 mins. After discountinuation
of the reaction there are obtained 4.0 g of a dry product (yeld
43.8%) having an Mn of 433, a Br number of 41.7 and a contents
of residual C12 of 1670 ppm. Hydrogenation has been carried
out on this product according to the procedure reported in
Example 1 with results which are essentially equivalent.
E X A M P L E 4
With the same procedure as reported in Example l there
are charged 2.0 millimols of anhydrous HCl diluted in 1 ml of
nor.pentane and 14 g of a C4 hydrocarbonaceous fraction having
a composition equal to the reported in E~ample l.
~he reaction is started at the temperatureof 20C by
introducing 1.5 millimol of AlEtC12 diluted in lO mls of nor.
pentane.
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(Molar ratio of HCl to AlEtC12 = 1.33).
The temperature rises to 2gC and the reaction is
continued for 30 mins.
There are obtained 9.1 g of a dry product (yield 100~)
which has an Mn of 538, a bromine number of 36.3 and a contents
of residual C12 of 1190 ppm.
E X A M P L E 5
With the same procedure as set forth in Example 1 there
are charged the same quantities of C4 hydrocarbonaceous fraction
and of HC1.
The temperature is set to 0C and the reaction is started
with the same amount of AlEtC12 as reported in Example 1. The
temperature rises to 4C and the reaction is allowed to proceed
for 30 minutes whereafter there are obtained 5.0 g of a dry product
(yield 54.7%) having an Mn of 524, a bromine number of 32.5 and
a contents of residual C12 of 1080 ppm.
E X A M P L E 6
With the same procedure as in Example 1 there are
introduced the same amounts of C4 hydrocarbonaceous fraction and
HCl, and the temperature is set to 80C and the same amount of
AlEtC12 reported in Example 1 are introduced.
A temperature increase to 85 C is experienced and the
reaction is allowed to proceed for 30 mins. There are obtained
6.10 g of a dry product (yield 66.8%) having an Mn of 215 a Br
number of 54.5 and a contents of residual C12 of 1850 ppm.
E X A M P L E 7
With the same procedure as in Example 1 there are
charged 4.5. millimol of anhydrous HCl diluted in 1 ml of nor.
pentane and 14.0 of a C4 hydrocarbonaceous fraction having a
composition equal to that reported in Example 1.
The temperature is stabilized to 20C and the reaction
is started by introducing 1.5 millimol of AlEt3 diluted in 10 mls
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of nor.pentane (Molar ratio of HCl to AlEt3 = 3.0).
The temperature rises to 30C and there are obtained
7.82 g of a dry product (yield 85.6%) having an Mn = 405, a
bromine number of 39.5 and a contents of residual C12 of 1058
ppm.
E X A M P L E 8
With the same procedure as in Example 1 there are
introduced 3.0 millimols of anhydrous HCl diluted in 1 ml of
nor.pentane and 14.0 g of a C4 hydrocarbonaceous fractions
having the same composition as reported in Example 1.
The temperature is stabilized to 20 C and there
introduced 1.5 millimols of AlEt2Cl diluted in 10 mls of nor.
pentane.
The molar ratio of HCl to AlEt2Cl is 2Ø
The temperature rises to 31C, the reaction is allowed
to proceed for 30 mins. and there are obtained 8.90 g of a dry
oligomer (yield 97.4%) having in Mn of 363, a bromine number of
40.4 and a contents of residual C12 of 1080 ppm.
E X A M P L E 9
With the procedure as reported in Example 1 there are
introduced 2.25 millimols of anhydrous HCl diluted in 1 ml of
nor.pentane and 14.0 g of a C4 hydrocarbonaceous fraction having
the same composition as reported in Example 1.
The temperature is stabilized to 20C and the reaction
is started by adding 1.5 millimol of AlEt sesquichloride diluted
in 10 mls of nor.pentane, the molar ratio of HC1 to AlEt sesqui-
chloride being 1.5.
The temperature rises to 29C, the reaction is continued
for 3¢ mins. and there are obtained 8.5 g of~a dry product
(yield 89.8~) having an Mn of 450, a bromine number of 39.5 and
a contents of residual C12 of 1120.
