Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
1(~376914
It is known to polymeri~e cyclo-alkenes, in particular cyclopen-
~-~ tene, in the presence of tungsten or molybdenum salts, organic alum~nium
compounds and oxygen compounds. In this process it is preferred to use no
diluents in order to achieve a high monomer concentration and conversion.
Nevertheless, only moderate yields (30-50%) are obtained using high catalyst
concentrations, while the absence of a diluent impedes temperature control
and the addition of polymerization terminators, stabili~ers, etc.
The present invention affords a process in which, even in the
presence of diluents, high conversions of cyclo-alkenes to polyalkenamers
having a high trans-content are possible. A high trans-content in the poly-
alkenamer is desired to ensure good processability into, for example, tyres.
The invention provides a process for the preparation of polyalken-
amers, which comprises polymerizing a cyclo-alkene, other than cyclohexene,
in the presence of a catalyst obtained by mixing a compound (A) of molybdenum
or tungsten, with an organo-aluminiumcompound (B) and an activator ~C) having
the general fornlula X (SOp)Y, wherein X represents an unsubstituted or sub-
stituted hydrocarbyl group or halogen, p is 1 or 2, and Y halogen.
Polyalkenamers are mainly linear unsaturated polgmers, the forma-
tion of which may be represented as follows:
CH=CH
n ( ) ~ (CH2)m-CH=cH)n
(CH2)m
In this equation m represents an integer equal to or larger than 3, but not
equal to 4, and n the degree of polymerization. Probably as a result of the
high stability of its ring, cyclohexene (m=4) cannot be polymerized to a
product having a sufficiently high molecular weight. Preference is given to
polymers of cyclopentene. Cycloheptene, cyclo-octene and cyclododecene,
however, are also examples of suitable monomers. The invention also com-
prises the preparation of copolymers of cyclo-alkenes, for example with di-
cyclopentadiene
_ 2 -
~03'7~;4~
The polymerization catalyst is obtained by mixing the compound
(A) with the aluminium compound (B) and the activator (C~. The compound
(A) is derived from tungsten or molybdenum, in particular however from
tungsten In addition to the preferred halides, in particular the chlorides,
the compound (A) may also be mixed in the form of phenolates, acetyl ace-
tonates, complexes of carbon monoxide and phosphines, acetates, beneoates,
sulphates, phosphates and nitrates. Suitable examples of these compounds
6~ r6~ WJ6, WF6, WOC14, W02C12, WCls, WBrs~ W2Br2~ WC14~ WC12
W2C16, (pyridine)3, 3 WC12, 4AlC13, WCl(phenoxide)5, WCl (p.tert.butyl phen-
oxide)s, WC12(phenoxide)4, WBr3(phenoxide)2, WBr2(p.methyl phenoxide)3;
MoC15~ MoFS, MoC12(phenoxide)3 and MoF5Cl. Good results were obtained using
WC16, MoC15 and W(C0)5. (triphenyl phosphine).
Examples of organo-aluminium compounds which can be used in the
process according to the invention are:
Al(C2Hs)3, Al(i-C4Hg)3, Al(n-C6Hll)3, Al(C2H5)2Cl, Al(C2H5)Br2, AlH(i-C3H7)2
and Al(C2H5)2(0C2H5). Very satisfactory results are obtained using aluminium
trialkyls, aluminium dialkyl monochlorides and aluminium mono-alkyl dichlor-
ides for example Al(C2H5)3, Al(i~C4Hg)3~ Al(C2H5)2Cl a ( 2 5 2
Although the ratio between the quantity of compound (A) and that of
aluminium compound (B) is not bound to any definite limits, it is preferred
to use molecular ratios between 1 : 0.1 and 1 : 100, in particular between
1 : 0.5 and 1 : 20 Nor is the molecular ratio between the compound (A) and
the cycloalkene bound to definite limits, but it is generally between 1 : 10
and 1 : 100,000, preferably between 1 : 1,000 and 1 : 20,000.
Examples of suitable activators are SOC12, S02C12, C6H5~S02Cl,
c6H5-socl~ 4-CH3-c6H4-so2Br~ C6H5_so2J, C6H5-cH2-so2cl~ 4 Cl C6 4 2
i-C3H7-S02Cl. Good results were achieved using aromatic sulphonyl chlorides,
in particular benzene sulphonyl chloride. The molar ratio between compound
(A) and activator (C) may vary within wide limits, but preferably lies
between 4 : 1 and 1 : 100, in particular between 1 : 1 and 1 : 30.
~ 2 '
~ ~ 3 ~ 6 ~ ~ _ 4 _
Thc polymerization can best be carried out in a homogeneous
medium. ~ghe~t possible monomer concentrations, iOe~ u~lng no
or little dlluent, enha~ce the rate o~ conversion~ ~ut on the
other h~nd impede temperature control an~ the ~tirring and
sdmixture of ~urther ingredients. The inventlon all~ws even
lsrger quantities o~ diluent to ~e u~ed withou~ leadi~g to
w cceptable reaction conditiona. Representatlve examples o~
diluenta are liquid aromatic hydrocarbons auch as benzene and
toluene, hydrated ar = tic hydrocarbons such aB tetral~n, ~lquid
~0 ~llphatic hydrocarbon~ ~uch aa pent~ne, hexane, petroleum ether
~nd decsnel and cycloaliphatic hydrocarbonc ~uch 8~ cyclohexan~
decalin and cyclo~octane.
The pol~meri~at~on temperature may vary within ~ride ll~it~,
~or e~ample between -75C and ~150C, preferably between -35C ana
+80C Aa a rule, approximatelg autogenou~ prea~ure i~ used, ~hich
is generated by the reactants under the prevsiling re~ctio~
conditions~ Ihe polymerization, howbver, msy al~o be carrie~ o~t
at hlgher or lo~Jer pressurea.
If de~ired, the average molecular weight o~ the poly-
alkenamer can be lowered by carrying out the polymerization ln
the pre~e~ce o~ an acyclic aIkene such as pentene-l and cis-
pentene-2. The scyclic alkene i8 u~ed ~or exsmple ln a qusntity
o~ 0.0001 to 5 mol.~, pre~erably 0.01 to 1 mol.%, based on cyclo
alkene.
The polyalkenamer~ whlch can be obtained accordlng to the
invention are synthetic rubbers, which, in the preeence or in the
ab~enc~ Or the customa.~y sdditives can be proce6sed into
vulcQnized articles. ~11 qusntitie~ o~ the polyslkenamers, ~or
example up to 201Po by weight~ m~y al~o be mixed with thermopl~t~c
polymers such as polystyreneJ in order to improve the imp~ct
~tren8th.
E2~AMPLES
I. A number of pol~merization experiments were carried ou~ in a
dry, nitrogen-~illed agitated reactor, ~o which end in each ca~e ~
quantity of 100 mmol o~ cyclopentene (8.8 ml) in B certain qusntlty
~lO37~
of solvent wa~ mixed at 25& with moIybdenum pentaohloride and
aluminium tril~obutyl in quantlties of 0.0$ ~mol e~ch, and with
~he activator (see Table A). 0.05 mol.% of pentene-l bessd on
cyclopen~ene was added as molecular weight modi~led (not ln
experlment (o)~. After 4 hour~ the polymerlzation wa3 termlnated
by adding 5 ml of methanol, whlch contained 2 ~/1 o~ .5-
trlmethyl-2,4,6-tris-(3,5-di-tert.butyl-4-hydroxy-b~nzyl)benzene
a~ antl-oXidant. The reaction mixture was then poured out with
stlrrlng ln~o methanol to which an am~unt of 10 ml per lltre had
been added of a 35% by ~eiBht ~olution o~ H~l In water. A~ter
sep~ratl~n, drylns ~nd welghlng o~ ~he preoipitQted polypentenaKer,
the oonver~lon was oalculated ~nd the perOentagQ of transdoubl2
b~n~s ~&~ determined by lnfrared analysis. The result~ are
summarized ln Table A. A da~h in the Table slg~lrle~ th~t the
determlnatlon oonoerned was not cnrried out or that the ln2r~dlent
wa~ not used.
Table A
Experlment (a) (b) (c) ~or
_ com~Qrison
solvent, ml 5.5 Chloro_ 5.5 ohloro- 5 ohloro-
benzene ~ benzene + benzene
2.5 toluene0.5 toluene 0.5 toluene
actlvator, mmol 2-5 C6H5~302cl-5 S2C12
oonverslon, ~ by
weI6ht 67 43 0.7
llmiting vlscoalty
~umb~rX~nJ , dl/6 2.5 2.8
tran~-content, ~ - ~6
. . .
x measured in toluene at 25C.
Table A shows that without actlvator the oonversion is negli~ible.
II. Example I waa repe~ted, the reaction conditions belng varied
as shown ln Table B.
~(~3~44 - 6-
'n~ble ~
E~per~ment (d~ (e~ (f) (~) for
(i C4~19)3, (d)-(f) O.lO 0.05 0"05 o,~ Al(C2H5)Cl2
MbGl5, mmol O.lO 0.05 0~,05 O.lO
5 . Solvent, ml 9 toluene 5,5 chloro-~.9 chloro- 12 toluene
o- benzenebenzen~ +
octane 0,7 iso-
octane
Activator, mmol 2.50 -5 S02C12 1.25
6 5 2 6 5 2
Pentene-l, mol.% O.lO 0.05 O.lO
Polymerlz~tio~
temperature~ C 25 25 25
Polymerizatlon time,
houra 4 24 4 24
Converaion, ~ by
w~lght ~ 64 62 55 O.l
~imiting ~i6c08ity
number, dl/g - 2.6 1.7
Trans-content~ % 84 79 82
III. Ex~mple I was repeated usi~g WC16, tungsten-hexa-c~rbo~yl,
~(CO)~, and t~e triphenyl phosphine complex o~ tung6ten pen~acarbonyl,
W(C0)5. (P~3). No molecular weight modi~ied W~B u8ed,
me re6ults are shown in T~ble C.
.
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