Note: Descriptions are shown in the official language in which they were submitted.
Tbe present invention relates to En improved procesS for the pTO-
duc~ioD of liq~id polybutcdiene, consisting mainly of 1,4-cis unit8 ~Id bav-
ing low valuas of ~olecular wei6ht.
It is already known that it is poseible to tisnsform b~ltsdiene into
polyn.ers of hlg~, moiecular weight witn predominent'y l~L-cis structure, by
usir.g catslysts consisting of an alkylaluminium hslide and a transition metal
compound.
It is also known that it i5 po6sible to produce 1,4-cis polybut-
adiene havir.g low vslues o~ molecular weight, by means of catalysts consist-
10 ir.g of nr. alXylalun:-Dium halide and of a compound of nickel, solu~le in the
:eaction mecium.
~uch polybutndiene~ liquid at ambient tc~.peratllre, is used ma'nly
in the field of lac~uers and coatings.
The main ~haracteristic which determir.e the applicability of liquid
polybutadiene for the various specific uses is its viscosity, the value of
which depends above all on its molecular weight.
For example, for the use in lacquers for electrophoresis, wbich
currently constitutes the maJor field of application of liquid polybutadiene,
particularly low viscosity is required (~oo-800 cps).
2Q In the polymerization of butadiene to form liquid polymers by r!eans
of the catalysts cited above, considerable difficulties are usually found in
obtairin& the desired viscosity with acceptable consistency, since the vis-
coslty Yalue is Etrongly influenced by variations, even small, cf a large
number of reaction parameters, such as the butadiene/catalyst ratio, the con-
centration of the mor.omer in the reaction ~edium, the conversiou of the mon-
o~er ard others.
Furthermore the control of some of these parameterS~ such as for
exa~ple, the cortent of traces of moisture, cPn entsil particular problems
in ar. industrial process. The greatest difficulties are found when it is
wis~ed to prl!pare liquid polvbutadiene with 1ow viscosity, in a continuous
~nd reproducible mPr.ner, which is precisely wnat is required in the field of
lacque- fol electrophoresis
-1-
107~ 0
In these circumstances it is in l`act necess&ry to operate uith
economically less favourable conditions, such as low terperatures (and there-
fore lorg reaction times), lcw corversior.s of the monoDIer~ or particularly
high degrees of c'~iluticn; alternatively it becoLes necessary to introduce
other ccr.porents stish as comoncmers or chain transfer agents, thus making the
reaction ;,ystell: more c--mplex.
In every case in which it is intended to achieve low values of the
viscosity, it is neces..ary to control the content of r..oisture present in the
reection medium extre~ely f ccurately (+ 5 ppm of water) .
}n conclusion, the industrial prodtlction of liquid 1,4-cis pely-
butadiene involves consic'erable problems with regar~. to the consistency of
the quality of the product and these problems are accentuated in the case of
polybutadiene havir.g a high fluidity.
~ Geed has therefore been l'elt for providing a process for the pro-
duction of lic_uid 1 ,L_cis polybutadiene the charaeteristies of whieh are in-
dependent~ ~~ithin broad limits, of the polymerization eonditions of the but-
adiere, so as to ma~e it possible to obtain, .eprodueibly, products havinB
the desired eharaeter_sties and to conduct the Sf id polymerization in a simp3 e
and economic ~anner, even in the ease of the produetion of polybutadiene hav-
20 ing partieu3arly lo~ viseosity.
Such resu3ts are obtained by mealts of the process of the presentinvention .
Ihus, 'che invention provides a process for the preparation of liq-
uid polybutadiene havin~ preva3ent 1,4-cis-structure, characterized by poly-
merizing butadiene in solution in a sol~rent consisting of one or more sat-
urated aliphatic or eye:oaliphatie hydrocarbons, or a mixtlure of the latter
with up to a maxi~um of 3Q wt.% with respect to said mixtt~Ae, of one or more
aromtie h$-drocarbcns, in a weieht ratio between said sclvent and said but-
adiene of at least 0.8:1, oper&tin6 at a temperature not exceeding 9O C and
30 in the presence of a catalyst consistirg of e product definable by the for-
mula R3~12Y3, rhere R is an a3kyl radical and X a llaloger., and an or~anie
eor.pound cf nickel, in an Al/Ni atomie ratio of from 2:1 to 50:1, the organic
_ ~ _
'7tj~.'`0
co~yound of ri Xe3 being used in an ~mount of from 0.5 10 to 3.0 10 moles
per mole of butadiene, and recoverine the liquid polybutadiene from the reac-
tioD product thus obtained.
~ J operatin~ in thc c~ilditions described, polybutadiene is obtained
t-hich typic~liy has a cGntent of 1,~ units ol` +he order of 98-99~ and of 1,~-
cis units of approximately oO~, and a viscosi+y of frcm 500 to lO,000 cps,
measured at 23 C.
As will be shown in the experimental examp]es, the chsracteristics
of the l quid polybutQdiene thus producc~l are irdependent, uithin wide inter-
vals, of the operating parameters, p&rticulqrl-y with re&ard to the degree Or
conversior., the quantity of catalyst, the nicXel/alllminium ratio in the said
catalyst emd the moisture cor.tent in the reaction medium.
Ir particulur tbe viscosity value is not appreciably altered by the
presen:e of water in amounts of up to approximately 50~ in moles uith respect
to the Dumber ol moles of alXylsl~m~in um sesquichloride.
LiXeuise, ~hen the solvent/butadiene weight ratio is grester than
about 2.5:1 the variations in degree of dilution do not appreciaboly influence
the viscosity value, wbilst for ratios Or from about 2.5:1 to about O.ô:l the
viscosity ~-alue increases in acontinuous and regular ma mer.
In conclusion, by operatine according to the process of the present
irvention it is pos~ible to obtain, with re6ularity, liquid polybut3diene hav-
ing the desired viscosity, by varying solely the temperaiure of polymeri~ution
(tbe viscosity increases in fact with increase in temperature) and/or the
concentration Or the nomer fed in.
It is also possible to produce liquid polybutadiene with high flu-
idity reproducibly uhile operating under economically favourable conditions.
The catalyst useful for the purposes of the present invention pref-
erably comprises an alXylalumini~mm ses~uichloride and an orsanic compound of
nicXel.
~ne alumir.~ compound is cefinab~e by the follouing general for-
mula : R~A12X3, uhere R is an alXyl radical cintainins generally from l to -,
carbon atoms, and ~ is a halogen, preferably chlorine.
-- 3 --
i~7Si1~L)
~ - Tt.e p~eferred aluminlum compolmds are methyl-, ethyl-, propyl-,
isopropyl-, n-butyl- anl isobutyl-alnminiuTn sesquichlorides
Instead Or àluminium compounds of the forrcula R~A12X3, it is also
possible to use rixtures of tria]kylalumillium and a halidc of a dialkyl-
alu~.inium, provided that the r&tio bet~cen the number cr n'~yl erGups (and
equivalently the r.u~ber of atoms of haloeen) anc. th~ number of atoms of alu-
miniuri. is equal to 1.5:1, or at least very close to this value.
The organic compound of nickel is preferably tl.e acet~te, stearate,
oleate, acetylacetors te or naphthenate of nickel .
Furthernore, the utor.dc ratio between aluminium and nickel in the
catalyst is from 2:1 to 50:1, and ~referably from 10:1 to 50:1. Finally, the
com~ound of nickel is used in amolmts of fror. C.5.10 4 to 3Ø10 moles per
mole of butadiene, the best results beine achieved with ~ounts of the order
Or 0.65.10-4 - 2.C.10-4.
The solvent medium preferAbiy consists Or one or m.c,re saturnted
hydrocArbons. ~lso useful are mixtures of saturated hydrocarbons with aro-
matic hydrocarbons in which the ccntent o.` the latter does not exceed .sOS by
we i ght .
The saturated hydrocarbons may be linear, branched or cyclic, the
20 number Or carbon ntoms per r.~olecule bcin~5 generally of frcm 4 to 12 and pref-
erably from 5 to 8.
The saturated hydrocarbons may for example be chosen from n-pen-
tane, I ethylpentanes, n-hexane, cyc~ohexane, methylhexanes, r.-heptane,
methylcycïohexar.e, dimethylcyclopentanes, dimethylcyclohexanes, n-octane and
iso-octAne. The aroratic hydrocarbons may be benzene, toluene, ethylbenzene,
xylenes ard others.
It is ircFortar:~ ~ . t the amount of saturated aliplkatic hydrc-
carboDs in the solvent be within the lirnits i ndicated above.
As will b-- shcwn in the experimental examples, in fact, by us:n6
30 arcrcatic hydrocarbGns as the solvent, in conJunction witll the catalytic sys-
tem de-.cribe sboYe, the results which are obtained sre clearly inferior from
the Eoint of view Or reprodl~cibility, especially in tke case of liquid pcl~y-
-- 4 --
A
107t~1S0
~ butadiene wi+h lo~ viscosity The weight ratio between the solvent and the
butadiene fed in is ~referably at least 2.5:1, especially whcr. it is desired
to obtain lo~ iscosity polybutadiene, the upper limlt of tbis ratio being
dictated cssenti~ y econo~ic factcrs.
For colybutadiene ~-ith visccsity vslues of from 650 to 850 Cp9 (at
23~C) the best results are cbtaincd by using solvent/butadiene weight ratios
of from 2.5:1 to abcut 5:1.
The reacticn temperatlure is preferably frcm 30 to 75 C, deoending
c.. the viscosity t is intended to cbtain. It is also possible to operate
~ithin a ~ der ranee of values such as from -10 to 90 C. ~est results are
generally obtained ~hen using a temperatUle of about 40 C.
The presEure does not constit1.te a critical parameter. A pressure
slightly grea'er than atmospheric may -cn.eniently be maintained during the
polymerization.
The polyrerization period is generAlly such as to afford a conver~
sion not exceedlr.g 95~, and preferably from 65 to 90%, with respect to the
butadiene.
In the conditions described the times required to achieve conver-
sions of from 65 to 90p are g~r.erally of the order of o.8-~ ~ours, these
being lin~ed, above ~11, to the temperature and the degree of dilution em-
c)loyed . ''
Fir.ally, the poly~erization may be carried out discontinuous1y,semicontir.uolsly or continuously and in each case, when the cesired conver-
sion has been achieved, deactivation of the catalyst is carried out, for ex-
ample, by treatin~ the polymer solution ~ith an nqueous acid or basic solu-
tion, or by adding terminating aeents Eoluble in the reaction medium.
?~.e orgaric ~olution is then generally subJected to ~ashing with
de-ionizeci water in order to rcmove the metal ions, and the lisuic po,Jbut-
adiene is generally recovered by separating it from the solvent by evapora-
tiGn at subat~ospheric pressure. The solvent thus separated may be reusedfor polymerization after dehydration.
" . . . j .
~ T ~ V
Example 1
160 g of technical h2ptane, pre~,:iously distilled end dried over 3R
molecular sieYes ~.ere introduced, in a nitroeen atmosphere, into a 30G ml
dark glass bcttle, equipped uith a stainless steel valve on the stopper, and
pre~iously clear~ 'ried, ar.d decontaminated semeral times with anhydrous
nitrogen .
The ccTrpoâ-tion bT wei&ht cf' the said hept~re was as follcvs: sat-
urated hydrocarbons uitb 6 car~oD atcms 5.g58,0; 2-methylhexane 9.487; 2,3-
dimethylpentane 5.5T'8%; 3-methylhexane 13.259g; dimethy].cyclopentanes
20.450,~; ischeptane 2.068~; methylcjclohexane 14.157~; cyclopentane O.G41%;
ethylcyclopentane 0.835S; n-heptane 26.638,~; saturated hydrocarbons contain-
iDg 8 carbon atoTrs 1.588',~ .
30 g of batadiene (purity 99.8~), 1.7 ml Or a o.o85 ~: solution of
nickel naphthenute in heptane and ~inally e ~ of u 0.l 1~ solution of ethyl-
aluminiu~ sesquichloride in heptane were then introduced into the bottle in
the g iven order.
'~e bottle Yas then subJected to agitation in a thersostatical]y
controlle2 bT~th at Lo C.
After 90 ~inutes the contents ol~ the bottle were poured into a
20 beaker containing 1 litre of puremethanol in which had been dissolved 0.3 8
Or 2,6-di-tert-butyl-4-1re~.hylphenol. The product thus obtained was washed
repeatedly with setbanol and then dried in a vacuum oven at 60 C, for 15
hours .
21.27 6 Or a transparent and colourless liquid polymer havin6 a
viscosity of o30 cps at 23C were obtained. The IR and N~IR microstructural
deteIlLination gSave the fo'louing results: l~h-cis 80.5,S; 1,4-trans 18.5~;
vinyl 1~.
The results of the test are summàri: ed in Table l; in the said
table (as in the others which are to rollou~ by Al/Ni is D:eant the atosic
30 ratio bet~een alumiDiu~ and r.ickel in the catalyst.
-- 6 --
.~ .
107~1~0
Table 1
Example ~utadienc/l;i Al/l:i Ccnversion Viscosity
n~hthenate (inoles) (atoms) (~) (23 C,cps)
4200 13 70.q 830
2 4200 30 77.1 836
Exam~le 2
T~e test of Example l was repeated, introducin~ 18 n;l of a O.l M
solution of ethylall~inium sesquichloride. After 90 minutes 23.13 e were
obtained of a polymer having a viscosity of 836 cps at 23 C and the follow-
ir,g ~icrostructure: 1,4-cis 80.0~; l,4-trans 19.3~; vinyl 0.7%. The rerults
are summsri-ed in Table l.
F,Ya ~e~ 3-1~
T'rese cxamples were carried ou`, in accordance uith the procedure
described in ~ample l, the quantities o'` the reagents being varied as shown
in Table 2.
Ir. particular, the moisture ~ontent was PdJusted by suitable niixing
OI ;ceasured quantities of anh~vdrcus solvent and o~ solvent saturated with
water ard by determinin8 the water content oi` the mixture with a Panometrics
hygrometer, rlcdel lO00.
E~emples 3-7 uere carried -ut .ith the technical hepta~le of Example
l and with different oisture contents.
E~amples 8 to l3 are for comparison and were carrie~1 ou' by using
toluene e.3 tke solvent Isedium.
In all the examples the polymerization was stopped afte:^ 90 min-
utes.
rbe results are given in Iable 2, whicll also includes the values t
relating to Exampie 2 previously described.
Ex~:Ples 1~22
These tests were carried out in accordance with the procedure of
Example l using a molar ratio between t~:e ethyl sesquichloride and the nickel
naphtnenate equal to 30:1 and a moisture content corresponding to a molar
ratio setueen the water snd ethylall3r,iri~:l sesquichloride equal to 0.2:1.
-- 7 --
107~1S0
In Exsl~.ples 20 to 22, Eiven for the purposes Or comparison, toluene
was used as the solver.t medium.
The polymeri~stion uas interrupted at difrerent times in tl,e vsrious
Exs~ples ar.d the results ere given in 'r~ble 3.
Exalsples 2~-28
~ hese runs ~rere c rried out in accordance with the procedure Or Ex-
ample 1 in &n anhydrous medium, the resction medium/butadier.e weight rat- o
being varied, the qusntity cr catalyst corresponding to a bt~tadiene/:nickel
naphthenate molar ratio equal to 8,4Go:l and the molar ratio between ethyl-
10 alumlniu~L sesquichloride and nickel naphthenate being equal to 30:1. Ex-
~ples 26 to 28, eiven for the purposes of comparison, were carrie~ out usine
toluene a5 the solvent rledium. The r~ sult~ are 6iven in ~able 4.
xarlple 29
This test was carried out as in Fxample 1, heptane and toluene in a
3:1 weight ratio beine used as the solvent mediu~l nqd the quantity of cata-
lyst bein6 such as to ensure a butadiene/nickel r.aphthenate molfla ratio Or
8,400:1.
A liquid polymer having a viscosity at 23C of 750 Cp8 was obtained,
with a yield of 71%. The micrcstructural analysis gave the following re-
^0 sults: ] ,4-cis 81~, 1 ,4-trans 18.2~; vinyl o.8~.
EY.aLIple 30
~ his test was carried out as in Exa~ple 1, at a temperat~tre Or 60C,
usin~ a quantity of catalyst equivalent to a butadiene/nickel naphthenate
molar ratio of 8,400:1 and a solvent meditu~/butadiene weight ratio of 3:1.
In 60 rinutes a liquid polymer, having a viscosity at 23C
10';~6150
Cl U ¦ a t ~0 C~ o N N
~I 0~
1.~ ~0 t-~ ~ ~r O u~ O r-, . .
~ tU~ tt- tt- tt- o ~ t- ~
C~l rl
~1 o o o o 3 ON 3
~0`'
to
~ ~ 'l ~ ~'~ ~ ~ ~ ~ ~ ~ .
~ C~ o 3 N N N co ~ N N N
~ .'
¦ !~ ~ F S .~ ~
CJ \~ t~ 0~ ~ N ~-
_ 9 _
,
1~)761S()
~, ~
Ex~mp-e Sol~er.t ti~e conversic:n VisC05ity
t~r,in) _ (~) (23 C c~.s)
14 heptane 50 61.9 770.
heptane 60 68. ô 814
16 bept&ne '70 70.1 851
17 heE~ane 80 73.1 8h2
16 heptllne 9ù 78.4 844
19 heFtane 12C 8b.o 971
toluene 5G 64.o 905
21 toluene 90 79.2 1490
22 t.oluefie 120 90.0 5200
Table 4
E~csmple Solventsol~./butsdlene conversion viscosity
(in uei&bt) (%J (23C cps)
_ _ _ _ _ _ _
23 hept&ne 3.0 76.2 725
24 heptane 4.5 75.0 675
heptane 5.5 72.3 700
26 toluene 3.0 72.0 2758
27 toluene 4.5 h2.7 1623
28 toluene 5.5 47.0 793
-- 10 --
~ . ' '.
'
.. 1~'7{i150 , -
equal tc 3C20 cps, was obtained with~yield of e8%. 'rhe microstructural
snalysis gave t1he foll~-in6 results 1,4-cis 77~; 1,4-trsns 21.5Z; vinyl
1 .5~.
E~a~ple 31
This test ~as carr,ed out ss 1~ Exar,p]e 1 with a butadieneJnickel
naphthenate r olrar ratio of c',LC0 l end rith n solvent medium/butadiene weight
ratio of 2: 1.
In oC mirl~'es A liquid polymer, ~avine a viscosity at 23C of 3407
cps, was obtained ~ith a yielA of 90.2~. Th- microgtructur~ analysis eave
10 the fGIlowin6 results: 1.4-Ci9 79.5Si 1,4-traus lg.8%; vin~1 0.7S.
Exam~le ,2
This test Yas carried Cllt as in ExRmple 1 witll a butadielle/nickel
naphthenate r olar ratio of 16,800:1, sr~th a moler ratio between the etbyl-
aluminiu~ sesquichloride and the nickel naphthenate c,f 30:1 and uith a sol-
vent medium/butadiene Yeight iatio of 1:1.
ID 60 minlltes a liquid polyrner with B viscosity at 23C of 5747
cps wns obtr~ined, Yith a yield of 88.5~.
The microstructural analysis gave the following results: 1 ,4-cis
79.8,~; 1,4-trans 19.6%; ViDYi O .6%.
20 Exar,lPle 33
Ihis test sras carried out as in Example 1 with a butadiene/nickel
naphtbenate molar ratio of 16,800:1, ~ olar ratio between the ethylaluminium
sesquichloride and the nickel naphthenate of 30:1, and a weight ratio between
the sollrent ~edium snd the butadieDe of 3:1.
~ y o~eratine at 70C and for 60 minutes a liquid I)olymer having a
viscosity at 23C Or 5263 cps was obtained with n yield of c7.2S.
q~e microstructural analysis gave the follo~ine results: 1,4-cis
77.2S; 1,1;-trans 20.9S; vinyl 1.9;~.
ExamPle 34
17,424 g of the technical heptsne described in Exanple 1, pre-
viously dried on 3~. ~olecular sieves, and 5,850 g of anhydrous butadiene were
introduced, in a nitro~en atmo~phere, into a stainless steel autoclave of 37
-- 11 --
., .
;
10~i150
litre cap~city, eouipped with an agitator, and previously cleaned, dried and
the~ repePtedly pllrged under vacuum and with nitro6en.
Ibe te~perature Or the autccalve was then broug~lt to 40C and
15,13 g cr a 0.85 M sGlution o~ n~ckel naphthenate in toluene and tben 100
6 of a 2 ~I sclution of ethylal~minium sesquichloride in heptane were adc'ed.
The tempernture was held constant at Lo C ar.d the kinetics of the
reacticn was followed by taking, at ;eEular intervals, samples of the reac-
tion mixtu.o from the bottom of the autoclsve by neans of Q syrin6e.
~hen after 100 mir.utes, the con-/ersion hsd reached 77~, the ac-
tion mixture was transferred, in a nitrogen atmcsphere, into an 120 litre
reactor under agitation, containing 60 kg of demineraliæed water acidified
with 'nydrcchloric acid up to pH 2.
~he organic phase was ther repeatedly washed with water and f'inelly
the liquid polymer was recove-ed by remo~ring the solvent at subatmospheric
pressure in a thin film evaporator.
The polybutadiene had a viscosity of 885 cps nt 23C and had the
following microstructure; 1,4-cis 82~; 1,4-trans 17.5~; viny 0.5%.
Furthermore, the sai2 polybutadiene had a dry matter titre equal
to 99.98~ and a residual nickel content of 1.8 ppm.
xam~le 35
In this test, which ~as carried out con'inuously, three stainless
autoclaves arran6ed in series wele used, each being equipped ~ith an agitator
and an external ther~ostating Jacket; their capacities were 54, 54 and 37
litres respectively.
Operating at 40 C, the following flo~s ~ere fed into the botton of
the ~irst reactor: ar.hydrous technical heptane 33,000 g/hour; anhydrous but-
adiene 11,000 g/hour; 0.023 M solution of nickel naphthenate in heptane 500
g/hour; o.36 K solution o, ethylaluminium sesquichloride in heptane 5G0 g/
hour.
~,en the system had stabilized, de~erminations Or the con-iersions
carried out on the reaction mixture in each of the three reactors gave the
following results: 1st reactor 60~; 2nd reactor 78%; 3rd r~actor 86~.
- 12 -
A
. ~ ~
107t~S0
- ~ ~ke antioY.Jdant of ExAmple 1 was added to +he flow dischnrged from
the top of t~e third resctcr and the flow was then washed, first with water
acidified wi+,k kydrochlGric acid (pH 2) and then with demineralized ~ater.
Finall~, the li~uid polyme~ was recovered by removing the solvent
'n a tllir. film evaporator. ~he polymer had a dry matter titre equal to
99.2~, a viscosity at 23C of 762 cps, a residusl nickel content Gf 2 ppm ar.d
the follo~ing microstructure~ cis 81.5~; 1,4-trsns lo.O~; vinyl 0.5%.
Tbe deternin~tiqr,s of viscosity were carried out on the li~uid
polybutadiene with a Rheomat 15 Contraves rotational visco~eter at 23 C +
0.1C.
- 13 -
