CA1047698A

CA1047698A - Polymerisation of dienes

Info

Publication number: CA1047698A
Application number: CA221,316A
Authority: CA
Inventors: Eberhard Muller
Original assignee: Bayer AG
Current assignee: Bayer AG
Priority date: 1974-03-07
Filing date: 1975-03-05
Publication date: 1979-01-30
Also published as: JPS50122585A; IT1029946B; BE826306A; NL7502675A; FR2263258A1; ES435345A1; GB1461373A; FR2263258B1; DE2410913A1

Abstract

Abstract of the Disclosure Process for the preparation of diene homo- and copolymers, characterised in that a conjugated diene, optionally together with an aromatic vinyl compound is polymerised in an inert organic solvent at temperatures of from 0 to 70°C in the pre-sence of a reaction product of an organometallic lithium, so-dium or potassium compound and a primary monoamine or primary or secondary diamine as catalyst.

Description

.

This invention relates to a process for the preparation of diene homo- and copolymers wherein a conjugated diene is polymerised in an inert organic solvent at temperatures of from 0 to 70C, op-tionally together witll an aromatic vinyl compound, in -the presence of a reaction product of an organometallic li-thium, sodium or potassium compound and a primary monoamine ` or primary or secondary diamine as catalyst.
Suitable conjugated dienes for the process include, in particular those containing from 4 to 8 carbon atoms, for exam-ple, butadiene and isoprene; suitable comonomers are, in par~
ticular, styrene and its derivatives. The comonomers ma~ be used in quantities of up to 50 % by weight, based on the total quantity of monomers.
Suitable solvents are, in particular, aliphatic and aro-matic hydrocarbons~ such as hexane, cyclohexane, benzene9 to-luene, xylene or mix-tures -thereofO
The catalysts used according to the present invention are ` reaction products of organometallic lithium, sodium or potas-I sium compounds and a primary monoamine or primary or secondary ;l 20 diamine.
To prepare the catalysts 9 a solution of the amine in a hydrocarbon solvent of the type required for polymerisation is reacted with the organometallic compound in a molar ratio of ~ 1 : 2 at 0 to 25C. Many of the reaction products are soluble -l 25 and may be used directly as ca-talysts.
Amines of the following formulae are particularly suitable:
H
R ~ ~ H

(I) : ~, .:

N-(CH2)n-N~`R
(II) Rl , Rl ~ N-(CH2)n~1-(cH2)n N \ (III) Rl R Rl wherein R represents an alk~l group having from l to 20 carbon atoms, a cycloalkyl group having from 5 -to 7 carbon a-toms or an aryl group having from 6 to 20 carbon atoms; two of the groups Rl in a molecule represent R and the other two represent hydrogen; and n represents an integer of from l to 20.
~he ~roups represented by R may, in particular, be alkyl groups having from l to 6 carbon atoms, cyclohexyl, phenyl, tolyl, naphthyl or alkyl-substituted naphthyl groups.
xamples of suitable amines of this type include N-butylamine~

2-ethylhexylamine, cyclohexylamine, aniIine, n,n-diethylene-diamine, N,N'-dimethylethylenediamine, N,~'-diphenylethylene-diamine, bis-(2-methyIaminoethyl)-methyl-amine and 1,5-bis-:, methylaminonaphthaleneO
Suitable organometallic compounds are, in particular9 lithium, sodium or potassium alkyls containing from l to lO
, .
carbon atoms in the alkyl group, for example N-butyl-lithium, ~' ! sec--butyl-lithium, and phenyl-lithium. The reaction 1 l products of the alkali metals lithium, sodium and potassium ,; :
with aromatlc hydrocarbons are also suitable, e.g. the adduct of sodium or potassium with naphthalene. Instead of ~ i thes1e reaction products, the starting compound~, i.eO the alkali metal and the aromatic hydrocarbon, may be used~
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Polymerisation itself is generally carried out by adding a further quantity of solvent to the catalyst solution prepared as described above and adding the monomer or monomers and main~-taining -the reaction mixture at temperatures of 0 to 70C so that polymerisation will proceed.
~he catalysts cause the production of so-called 'qiving polymers", i.e~ polymerisation comes to a stand3till when the reserve of monomer in the reaction mixture has been polymerised. Polymerisation resumes when more mo~omers ; 10 are added. It is thus possible to produce block copolymers either by using two-monomers simultaneously (for example, butadiene and styrene) or by first polymerising one monomer and then adding the second monomer when polymerlsation has ceased.
The polymers obtained generally contain two po]ymer-isaticn active points per molecule. Block copolymerisation therefore gives rise to so-called'three-block copolymers"
in the case of a butadiene-styrene sy~tem, in other words a polymer consisting of a polybutadiene block with a poly-styrene block at each end.
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' Polymerisation may be stopped in the usual manner, eOg. by the addition of hydroxyl compounds, such as an alcohol. ~he polymer may be i~olated from the resulting polymer solution, if desired after first stabilizing it, by precipitating it, for example, with alcohols~ by evaporation off the solvent or by steam distillation.
~lternatively, polymer~ which 9till have a polymerisa-tion activity may be directl~ reacted in solutions thereof , .
with compounds which introduce reactive groups at the chain

3 ends. ~or example, if a reactant, such as ethylene oxide, . ' .
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is used for this purpose, products with OH end groups are obtained. These products may be cross linked by chemical means, for example by reaction with isocyan-ates.
Since the catalysts according to the invenri tion are generally soluble in hydrocarbons, they may easily be added in controlled quantities so that the molecular weight of the polymers may be varied within wide limits. The diene polymers generally contain only a very small proportion of 1,2-structures. The 1,2-pr~portion is well belo~ 20% of the structural units. The activity of the catalysts may be modified and the 1,2-proportion in the polymer increased by the addition of tertiary amines or the addition of ethers, e.g. diethyl ether or tetrahydrofuran.
It is known in principle to produce polymers, e.g. diene polymers, with the aid of difunction~
radical-forming agents of cat~alysts, for example organic dilithiwm compounds have been used for this purpose. However, the difunctional radical forming agents previously proposed are either very difficult to obtain or insoluble in hydrocarbons or else they give rise to non-uniform diene~ polymers with a pre-dominantly 1~2-structure~.~

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Examples The ollowing Examples were carried out in anhydrous solvents under purified nitrogen in dry stirrer apparatus.
"n-butyl-lithium solution" is a 20~o solution o~
n-butyl-lithium in hexame. All -the reactions are carried out!at 20C unless indica-ted otherwise~ ~he products are worked-up ei-ther by precipi-tation with methanol to which 2 ~ 2 ~ -methylene-bis-6-tert.-butyl-4 me-thylphenol has been added as stabilizer (method o~ isolation A) or by reprecipitation followed by solution by evaporating off the solvent on a rotary evaporator with the addition of stsbilizer (method of isolation B).
The polymers are dried at 50C under vacuum. ~or analytical determinations, the polymers are purified by repre-cipitating them 6 times from 5% chloroEorm solution with methanol.
Example 1 , -a.) 17.4 ml of n-butylamine are added to 400 ml of toluene.
80 ml of n-butyl-lithium solution are added dropwise with cooling. Stirring is continued for half an hour ~ i after all o~ the~utyl-lithium solution has been added.
200 ml o~ butadiene are then added and the mixture is stirred for 20 hours (room temperature). 60 ml of ethylene oxide are then added at 40C and stirring is continued for a further hal~ hour (method of isolation ~).
b.) 17.4 ml of n-butyl-lithium are added to 400 ml of ~ toluene. 160 ml of n-butyl-lithium solution are adde~; dropwise with cooling, and stirring is co~tinued for hour a~ter all the butyl-lithium solution has been ~0 added. 200 ml of butadiene are then added and the

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- mixture is stirred at room temperature for 20 hours.
60 ml of ethylene oxide are then added at room temperature and stir~ing is continued for a ~urther half hour~
~xample 2 75 ml of n-butyl-lithium solution and l0.6 ~ of 2-ethyl-hexylamine are added to 400 ml of toluene and the mixture is stirred for half an hour. 200 ml of butadiene are then added, 40 ml of ethylene oxide are added dropwise after 20 hours and the mixture is stirred for a further half hour (method of isolation ~).
Example 3 79~5 ml of n-butyl-lithium solution and lO ml of cyclo-hexylamine are added to 400 ml of toluene and the mixture is stirred for half an hour. 200 ml of butadiene are then added.
40 ml of ethylene oxide are added after 20 hours and the mixture i5 stirred for half an hour. (method of isolation B).
xample 4 ~Z ~ 10 ml of aniline are added to 400 ml of toluene.
I
99.7-ml of n-butyl-lithium solution are added dropwise with I cooling. ~he reaction mixtuxe i9 then stirred for hal~ an hour at room temperature~ lO0 ml of butadiene are added and the mixture is stirred for 20 hours. 30 ml of ethylene oxide 3 ~are then added and the mixture is stirred for half an hour 25~ ~ ~method of isolation B).

~3~ ~ 10 ml of aniline are added to 400 ml of toluene. 99.7 ml : 1 ~
of n-butyl-llthlum solutlon are added dropwiæe wLth cooling.
~ lO ml of ~ZHF~are adde~d after all of the n-butyl-lithium `~Z~ 30 ~ ~olution has been~added, ~nd the mixture is stirred for hal~ ;

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an hour. 100 ml of butadiene are then added at room temperature and the mixture is stirred for 20 hours. Finally, 30 ml of ethylene oxide are added and the mixture is stirred for a further hal~ hour (method of isola-tion B).
~xample 6 10 ml of N,N-diethyl-ethylenediamine and 64.8 ml of n-butyl-lithium solution are added to 400 ml of toluene.
The mix-ture is stirred for half an hour and 100 ml of butadiene are then added. 30 ml of ethylene oxide are added after 20 hours and the mix-ture is stirred for half an hour (me-thod of isolation B).
xample 7 64 ml of n-butyl-lithium solution and lO ml of N,N-diethyl ethylenediamine are added to 400 ml of toluene. ~he mixture is stirred for lO minutes and 20 ml of triethylamine are then added and the mixture is stirred for one hourD
~ l litre of toluene and lOO ml of butadiene are then added and - , the mixture is stirred for 20 hours~ ~inally~ 30 ml of ethylene oxide are added and the mixture is stirred for a further half hour (method of isolation ~).
Example 8 64 ml of n-butyl-lithium solution and lO ml of N,~-diethyl ethylenediamine are added to 400 ml of toluene and the mixture is stirred for lO hours. 20 ml of ~H~ are then ~ 25 added and the mixture is stirred for one hour. One litre of ; toluene and lOO ml of butadiene are then added and the mixture ;;~ is stirred for 20 hours.
30 ml of ethylene oxide are then added and the mixture is stirred for a further half hour (method of isolation ~).

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xample 9 16 ml of _-butyl-lithium solution and 2.5 ml of NJN-diethyl ethylenediamine are added to 400 ml of toluene and the mixture is stirred for 15 hourq. 20 ml of triethylamine are then added and the mixture is stirred for one hour.
1 litre of toluene and 200 ml of butadiene are then added and ; the mixture is stirred for 20 hours. 60 ml of Rtyrene are then ; added and the mixture is stirred for 9 hours (method of isolation A).
Example 10 16 ml of n-butyl~lithium solution and 2.5 ml of N,N-diethyl ethylenediamine are added to 400 ml of toluene and the mixture is stirred for 15 minutes. 20 ml of triethyl-amine are then added, followed after one hour by 1 1 of toluene, 200 ml of butadiene and 60 ml of styrene and the mixture is stirred for 20 hours (method of isolation A).
Example 11 7.25 ml of N,N'-dimethyl ethylenediamine are added to ~i 1 1 of toluene and the mixture is cooled to -10C. 61 ml of ( n-butyl-lithium solution are ~dded dropwise. 10 ml of ~ tetrahydrofuran are then added at room temperature and the ; mixture is stirred for one hour and 500 ml of butadiene sre then added. After the reaction has started, the reaction mixture is cooled tb 0C and stirred for ZQ hours. Stirring il~ 25 is continued for half an hour after the ~ddition of 20 ml of ethylene oxide (method of isolation B).
Example 12 24 g of finely-shaved potassium, 32 ml of N,N'-dimethyl-ethylènediamlne and 38.4 g of naphthalene are added to 50Q ml o~,~H~ and the mlxture is stirred until all the potassium has , , ~I re~cted. 50 ml of styrene are then added dropwise at 0C.
;
~ - 8 -, , ', Stirring is continued for one hour ~fter the styrene has been added. 200 ml of the mixture ~re added to 1 1 of benzene, and 500 ml of butadiene are added dropwise at 0C. 80 ml of ethylene oxide are added after 6 hours (method of isolation B).
Example 13 Analogous to Example 12, except that 500 ml of isoprene are polymerised instead of butadiene.
Exam~e 14 1.2 g of finely-shaved potassium, 1.6 ml of N,N'-dime-th-yl-ethylenediamine and 1.92 g of naphthalene are added to 50 ml of THF and the mixture is stirred until all the potassium has reacted. 1.2 1 of toluene are added to the mixture and 300 ml of butadiene are introduced dropwise.
60 ml of styrene are added dropwise after 10 minutes and the mixture is stirred for 6 hours (method of isolation A).
Example 15 21.5 ml of n-butyl-lithium solution and 5 g of N,N'-~: diphenyl ethylenediamine are added to 400 ml of toluene and , the mixture is stirred for one hour. 1 1 of toluene and , 20 200 ml of butadiene are then add0d and the mixture is hea~ed to 50C for one hour. It is then stirred at room -temperature for 20 hours (method of isolation A).
Example 16 21.5 ml of n-butyl-lithium solution and 5 g of N,N'-diphenyl-ethylene diamine are added to 400 ml of toluene.
20 ml of THF, 1 1 of toluene and 200 ml of butadiene are added after one hour and the mixture is stirred at room temperature for 20 hours. 50 ml of styrene are then added and the mixture is again stirred for 20 hours (method of isolation A).
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Example 17 62 ml of n-butyl-lithium solution and 10 g of bis-(2-methylamino-ethyl)-methylamine are added to 400 ml of toluene and the mixture is stirred for one hour. 1 1 of toluene and 200 ml of butadiene are then added and the mixture is stirred for 20 hours. 30 ml of eth~lene oxide are add.ed and the mixture is stirred for a further hal~ hour (method of isolation B).
: Example 18 Analogous to 17, with the addition of 20 ml of triethyl-amine.
~xample 19 Analogous to 17, with the addition of 20 ml of I~.
. ~ Exa~ple 20 5 g of bis-(2~methylamineethyl)-methylamine and. 31 ml of n-butyl-lithium solution are added to 400 ml of toluene .~ and the mixture i9 stirred for one hour. 1 1 of toluene, l 200 ml of butadiene and 60 ml of styrene are then added and the - ~!
mi~ture is stirred for 20 hours (method of isolation A).
! 20 xamPle 21 5 g of bis-(2-methylaminoethyl)-methylamine and 31 ml of n-butyl-lithium solution are added to 400 ml of toluene . and the mixture i~ stirred for one hour. 1 1 of toluene and 200 ml of butadiene are then added and the mixture is stirred for 20 hours. It is then stirred for a further 20 hours ., after the addition of 60 ml of styrene (met~od of isolation A).
Example 22 I . 10 g of 1,5-bis-methylaminonaphthalene ~nd 47 ml of .i n-bubyl-lithium solution~are added to 400 ml of toluene and li 3 .the mixture is stirred for one hour. 20 ml of triethylamine -:

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are then added, followed after 15 minu-tes by 1 1 of toluene and 200 ml of butadiene, and the mixture is stirred for 20 minutes (method of isolation A).
Results of the ~xamples The total yields in each case are from 90 to 100~. ~he molecular weight r~-mges of the polymers obtained are relatively narrow and correspond to polymers which are obtained by stoichiometric polymerisation with conventional anionic initiators (e.g. naphthalene-lithium or stilbene-dilithium).

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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process for the preparation of a diene homo- or copolymer which comprises polymerising at least one conjugated diene in an inert organic sol-vent at a temperature of from 0 to 70°C, optionally together with at least one aromatic vinyl compound as a comonomer, in the presence of a reaction product of an organometallic lithium, sodium or potassium compound with a primary monoamine or a primary or secondary diamine as catalyst.

2. A process as claimed in claim 1 in which the diene has from 4 to 8 carbon atoms.

3. A process as claimed in claim 1 in which the diene is butadiene or isoprene.

4. A process as claimed in any of claims 1 to 3 in which styrene or a derivative thereof is used as comonomer.

5. A process as claimed in any of claims 1 to 3 in which the comonomers are used in an amount of up to 50% by weight, based on the total quantity of monomers.

6. A process as claimed in any of claims 1 to 3 in which the solvent is selected from hexane, cyclohexane, benzene, toluene, xylene or mixtures thereof.

7. A process as claimed in any of claims 1 to 3 in which an amine cor-responding to one of the following general formulae is used in the preparation of the catalyst:

(I) (II) (III) wherein R represents a C1-C20 alkyl group, a C5-C7 cycloalkyl group or a C6-C20 aryl group; two of the groups R1 in a molecule represent R and the other two represent hydrogen, and n represents an integer of from 1 to 20.