Note: Descriptions are shown in the official language in which they were submitted.
3 3
This invention provides an improved multi-
functional lithium con~iningcompound suitable for
initiation of polymerization in a hydrocarbon medium.
The initiator of this invention promotes polymerization
of a 1,3-diene to give a high degree of 1,4 addition
and is soluble or readily made soluble in polymerization
initiation quantities in a hydrocarbon medium.
More particularly, the initiator of this
invention comprises a multifunctional lithium contain-
ing polymeriæation initiating compound having the Formula:
~ ~ ~-(R )-C ~
1~,~ =/ CH2 CH2
R3 R3 Rl
Rl !
wherein Rl is hydrogen, a Cl-C16 alkyl hydrocarbon radical,
a cycloalkyl hydrocarbon radical, an alkoxy radical or an i
aromatic radical, R2 is a divalent organic radical having ;¦
at least 6 carbon atoms and at least one aromatic ring
which is directly attached to a carbon which ls attached
to a lithium atom and R3 is an alkyl radical containing j
from 1 to 20 carbon atoms, a cycloalkyl hydrocarbon radical
contalning from 4 to 16 carbon atoms or an aromatic ring
structure containlng from 6 to 14 carbon atoms.
R1 is preferably hydrogen. When Rl is other than
~ ~ !
. -
:, ' ' . . :
~98~3
hydrogen it may contain from 1 to 16 carbon atoms and ispreferably a hydrocarbon radical having a tertiary carbon
atom directly attached to the aromatic ring or an aromatic
ring struct~re
R2 may be an aprotic organic solvent soluble
oligomer or polymer of indefinite siæe~ but preferably
R2 contains 6 to 12 carbon atoms and is most advantage-
ously 1,4-phenylene, 4,4'-biphenylene or 4,4'-oxybis-
phenylene. R2 contains carbon and hydrogen, and option-
ally oxygen, iron, and/or sulfur. Oxygen and sulfur
when present are present only in the configuration of a
diphenyl oxide or a diphenyl sulfide. Iron is present
in the ferrocene configuration.
~ 3 ad~antageousiy contains from ~ lo 2d carbon
atoms and preferably contains from 3 to 10 carbon atoms.
The preferred R3 species is sec-butyl.
Also within the scope of the present invention
is a solution particularly suited for the initiation of
polymerizing a vinyl groupcontaining compounds which are
polymerizable in the presence of a lithium containing
catalyst, the solution comprising a major portion of a
liquid aliphatic, cycloaliphatic or aromatic hydrocarbon
solvent or mixture thereof and a minor proportion of a
multifunctional lithium containing polymerization initi-
ating compound of the Formula:
, .. . ~, ,
, . . .
.
.. . .. .
:~
9~3
7 Li Li 71
(R4)n (R5)m ~ 1
~ ~ C- (R2) C
Rl \~ C~2 CH2 \R
Rl R3 3
wherein Rl, R2 and R3 are as above set out,
and R4 and R5 axe individually chemically combined units
of 1,3-butadiene or isoprene or mixtures thereof where
n~m is at least 20~ Also within the scopa of the present
invention is a method for the polymerization of vinyl
compoundscontai~ng at least one vinyl cJroup and partic-
ularly vinyl hydrocarbon compounds which are polymerizable
in the presence of a lithium containing catalyst. The
method is characterized by contacting the vinyl compound
wi h the polymerization initiating compound of the
Formula:
~ ~ L-~R )~
characterized in that R~ is hydrogen, or a Cl to C16
alkyl hyd~ocarbon radical, cycloalkyl hydrocarbon radical,
alko~y radical, or aromatic radical; R2 is a divalent
... -- 3 -- .
.. : , - . ~: ~
. - ,
.
.. . ..
organic radical haviny at least 6 carbon atoms and at
least one aromatic ring which is directly a-ttached to
a carbon which is attached to a lithium atom, and R3
is an alkyl, cycloalkyl or aromatie radical containing
from 1 to 20 carbon atoms.
Advantageously, the steps of the method
comprise reacting a compound of the Formula:
Rl Rl
,, 2 ', 2
R--~ c-r -c~ Rl
wherein Rl and R2 are as above set out with a lithium
co~i.ni.ngcompound of the Formula:
. R3Li
wherein R3 is as defined above, and reacting the result-
ing product with isoprene or butadiene to provide a
multifunctional lithium eompound having the Formula:
Rl Li Li Rl
(R~)n (R~)m ~ ~ 1
R ~ ~ C-(R2)-C ~
\=~ / CH2 CH2
Rl 3 R3
wherein all of the substituents are as defined above and
subsequently contacting the resultant dispersion with at
- least one lithium polymerizable monomer to cause the poly-
merization of the monomer to a corresponding polymer.
- 3a -
Compounds employed herein include~
I. O O
~,C~/C\¢~ ~
4,4'-dibenzoyl-1,1'-biphenyl
II. ,C,H2 ,CIH2
[~C ~ C ~ ~ '
4,4'-bis(l-phenylethenyl)-1,1'-biphenyl
III. Li Li
~C~ ~C~ '',.
,CH2 C,H2
CH -CH-CH2CH3 CH3-cH-cH2cH3
(1,1'-biphenyl)-4,4'diylbis(3-methyl-1-phenylpentylidene)~
bis(lithium)
IV Li hi
'~C~O~C~
,CH2 CH2
CH3-CH-CH2C~3 CH -CH-CH2CH3
oxydi-4,1-phenylenebis(3-methyl-1-phenylpentylidene)
bis(lithium)
~7. 0 0
~fC~L ~C ¢~
4,4"-oxydibenzophenone
17,753B-F _~
~ , .
~IL~B913
VI. C~2 CH2 ,.
~C~ C~
Bis[4~ phenyle~henyl)phenyl]ether
VII. ,C,H2 ~ CH2
1,4~bis(1-phenylethenyl)benzene
VIII. ~ L ~ i
CH 2 CH 2
CH3_cH_cH2cH3 CH3-cH-cH2 CH3
1,4-phenylenebis(3-methyl-1-phenylpentylidene)bis(lithium)
IX. O O
~ ~ C,H3
.
C 3 .
4,4"-isopropylidenedibenzophenone .
, .
X. CH2 " 2 .
~ C ~ CH3 ~ ~
- I~J ~ c ~ ~ ,.,
CH3
2 5 2-Bis[4~ phenylethenyl)phenyl]propane
~ 5
17,753B-F
" ~ .
~8~ 3
- C ~ CH~ = , \ 3
C~3-CH-CH C~ CH3-CH-CH2CH3
(l methylethylidene)bi5-[4,1-phenylene~3-methyl-l-
-phenylpentylidene)]bis(lithium)
Compounds in accordance with the present in-
vention may be readily prepared from compounds of the type
hereinbefore disclosed and may be readily synthesized by
condensing an aromatic acid chloride with an aromatic
compound such as benzene, biphenyl, diphenyl ether and the ,'
like in the presence of a Freidel-Crafts catalyst such
as aluminum trichloride to form a diketone, the diketone `
having the katone groups separated by at least one aromatic
ring. The diketone compound is then subjected to a Wittig
reaction which transforms the ketone groups into 1,1-
-vinylidene groups. The divinylidene compound i5 then
contacted wi~h an organic lithium compound such as,
for example, secondary butyl lithium or tertiary butyl
lithium. The organo lithi~n compound adds to the double
bond to provide the desired compound. The resulting
dilithium compound on contact with small amount of buta-
diene or isoprene in an aliphatic, cycloaliphatic or
aromatic hydrocarbon solvent such as hexane, cyclohexane
or benzene becomes soluble. Generally the diene is
employed in a proportion of from 20 to 200 mole per mole
of the dilithium compound to xender the compounds soluble~
17,753B~F ~~
~ 1.
~g~
Example 1
A nitrogen purged reaction flask was charged
with 23.4 grams of biphenyl dissolved in 50 milliliters
of 1,2~dichloroethane. 85.5 grams of benzoylchloride and
an additional 100 milliliters of 1,2-dichloroethane were
added to the flask. The flask and conten-ts were then cooled
to about 10C and 71.5 grams of aluminum trichloride
was added slowly to the mix-ture with stirring. The solu-
tion became dark red in color. Over a period of about
four hours, the temperature of the reaction mixture wa5
raised to 85~C and maintained at that temperature for
a period of 17 hours. At the end of 17 hours, the re-
action mixture was poured into ice water with agitation.
The reaction mixture and ice water were then extracted
with about one liter of methylene chloride. The
water layer was discarded and the methylene chloride con-
taining the remaining mixture was washed with a
sodium bicarbonate solution, and then with water. The
methylene chloride solution was agitated with anhydrous
sodium sulfate for 30 minutes, the mixture filtered and
the filtrate evaporated to dryness. The crude product
obtained on drying of the organic layer was then washed
with methanol and subsequently with a 1 to 1 mixture o
benzene and ethanol. The product was recrystallized from
benzene.
17.6 grams of 4,4l-dibenzoyl-1,1'-biphenyl
(Compound I) were obtained having a melting range of
217-218C. Examination of the product with an infrared
spectroscope indicated an absorbance of a C=O which
agreed with that of the absorbance of benzophenone.
17,753B-F
Compound I was converted to 4/4 7 -bis(l-
-phenylethenyl)~l,1'-biphenyl (Compound II) in the following
manner:
10.6 millimoles of n~butyllithium as a 0~53 Normal
solution in benzene was admixed with 4.06 grams of methyl-
triphenylphosphonium bromide dissolved in 50 milliliters of
tetrahydrofuran in a nitrogen-purged glass reaction vessel
and the vessel maintained at ambient temperature (about
22C) for a period o~ 2 hours. A suspension of 2.05 grams
of Compound I in 30 milliliters of tetrahydrofuran was
added to the reaction mixture~ The reaction vessel was
maintained at room temperature for a period of about 16
hours. At the end of this period, the tetrahydrofuran was
evaporated and the remaining solid dissolved in a 1:1
by volume diethyl ether-water mixture. The ether and
water were separated and the ether layer washed with water
and subsequently the ether was evaporated. The crude
product Compound II was recrystallized twice from a 1 to 1
mixture of benzene and ethanol and the solid product
obtained washed with n-hexane, the 4,4'-bis(l-phenylethenyl)-
1,1' biphenyl (Compound II) had a melting point of 193-196C.
A benzene solution of Compound II was prepared in a
nitrogen-filled serum bottle equipped with a magne~ic
stirrer. The solution contained 0.5 grams (1l41 millimoles)
of Compound II and 70 milliliters of dry benzene. 702
milliliters of 0.482 Normal secondary butyllithium n hexane
solution was injected into the serum bottle with a hypo~
dermic syringe to provide 3.47 milliequivalents of sec--
-butyllithium~ The mixture was stirred at room temperature
for 2 hours and 40 minutes, and resulted in a deep blue
colored dispersion.
7~753B-F -8-
The foregoing treatment of Compound II was
repeated and a 15 milliliter portion of the resulting
dispersion was withdrawn and injected into a serum bottle
containing nitrogen and 0.05 milliliter of glacial acetic
acid. The dispersed material dissolved and the solution
color turned Erom deep blue to yellowO Lithium acetate
formed in the solution and was removed therefrom. An
infrared spectrum of the remaining liquid showed a complete
disappearance of the absorption band at 900 cm 1 indicating
that all vinyl groups had reacted with the sec~butyl-
lithium. The deep ~lue dispersion obtained by the treatment
of Compound II resulted in the formation oE Compound III,
(l,l'-biphenyl) 4,4'-diylbis(3-methyl-1-phenylpentylidene)-
-bis(lithium). Butadiene was polymerized using Compound III
in the following manner: A nitrogen purged reaction flask
was charged with 850 milliliters of degassed dry benzene
and the reaction mixture containing Compound III. ~bout
10 grams of 1,3-butadiene monomer was added and the
mixture agi~ated at room temperature for a period of about
1 hour and 35 minu~esO During this perio~d, the dispersion
became a solutionO -An additional 40 grams of 1,3-butadie~e
were added and polymerization proceeded for about 40
minutes and the temperature of the reaction mixture was
maintained at about 45-55C~ The reaction mixture was
subsequently cooled to room temperature a~d 4 milliliters
of distilled tetrahydrofuran were added with agitation.
When the tetrahydrofuran was uniformly dispersed, a
solution of 2044 milliequivalents of silicon tetrachloride
in benzene was added. Visible gels formed immediately.
After agitation for abou~ 20 minutesJ 1.5 milliliters of
glacial acetic acid was added and the mixture containing
the gel allowed to stand at room temperature overnigh~.
The resultant polybutadiene contained 40 percent ungelled
polymer and 60 percent gel, the foregoing being by weight
thereby confirming that the initiator compound was di-
unctional. The theoretical gel content was 86 percent.
For purpose of comparison, the foregoing
polymerization procedure was repeated with the exception
that sec-butyllithium was employed as catalyst
instead of Compound III. The recovered polybutadiene
was completely soluble in tetrahydrofuran, toluene
and benzene. No gels were observed.
Example 2
Compound IV, oxydi-4,1-phenylenebis(3-methyl-
-l-phenylpentylidene)-bis(lithium), was prepared in the
following manner:
A nitrogen-purged reaction vessel was charged
with 106.4 grams of aluminum trichloride and a solution
of 91.94 grams of benzoylchloride dissolved in 200 milli-
liters of methylene chloride. The reaction vessel was
cooled in an ice bath. A solution of 56 grams of diphenyl-
oxide and 20 milliliters of methylene chloride was cooled
to about 0C and added to the reaction vessel. A~ter a
period of two and one-half hours, the ice bath was removed
and the vessel warmed to room temperature and held at
ambient temperature for about 20 hours. After 20 hours,
some of the methylene chloride had evaporated and was
replenished~ After an additional hour~ the reaction
mixture was poured over iceO The resultant aqueous
mixture was ex~racted twice with methylene chloride. The
--10--
17,753B-F
~S~9~ 3
water and organic layers were separated and the water layer
was discarded. The organic layer was washed twice with a
ten weight percent solution of potassium hydroxide in
water~ The water layer was discardedO The remaining
organic layer was evaporated to dryness. The remaining
crude product was dissolved in benzene and decolorized
with charcoal. An equal volume of methanol was added
to the decolorized benzen~ solution and 56.03 ~rams of
4,4"~oxydiben~ophenone (Compound V), was obtained in the
form of white, crystal platelets. The procedure of Example I
was used to convert Compound V into bis[4~ phenylethenyl)-
phenyl]ether (Compound VI). A nitrogen purged serum bottle
was charged with 1.62 millimoles of Compound VI dis-
solved in 50 milliliters of dry benzene. Eight milli-
liters of a 0.482 Normal secondary butyllithium solution
in hexane was added to the serum bottle by means of a
syrinye. A dark red dispersion of Compound IV in benzene ~;
resulted. In a separate experiment the dispersion was
acidified in the manner of Example I and an infrared
spectral analysis indicated the absence of the 900 cm 1
band indicating the absence of vinyl groups. A nitrogen
purged reaction flask was charged with 780 milliliters of
degassed dry benzene and the dispersion of Compound IV
containing 1.62 millimoles thereof and 10 grams of 1,3-
butadiene. After about 90 minutes, the dispersion ~ecame
a solution and an additional 60 grams of 1,3-butadiene was
added. Th~ butadiene polymeriæed over a period of about 1
hour and 2 milliliters of tetrahydrofuran were added
with agitation. When the tetrahydrofuran had been uni~
1 1 _
17,753g-F
~8~3
formly dispersed, 2.09 milliequivalents of silicon tetra-
chloride in benzene were added. After about one hour,
1.3 milliliters of glacial acetic acid were added. Visible
gels were formed when the silicon tetrachloride was added.
The polybutadiene contained 56.6 percent gel. The theoretical
amount of gel was calculated to be about 65 percent. The
initiator was therefore difunctional~
~n additional quantity of Compound IV was prepared
by charging to a nitrogen-purged flask 0.88 millimoles of
Compound VI dissolved in 25 millilit~rs of dry benzene and
adding thereto with agitating 1.85 milliequivalents of
secondary butyllithium dissolved in 4.3 milliliters of
hexane. Compound IV began to form as a red dispersion in
benzene~ The dispersion was stirred for a period of 3 1/2
hours at room temperature and 2 milliliters of isoprene were
added to the dispersion. The dispersion was then heated to a
temperature of about 60C and after a period of about 10
minutes the red dispersion changed to a reddish-brown solution,
The solution was added to a nitrogen purged flask containing
40 grams of butadiene dissolved in 450 milliliters of dry
benzene. The reaction mixture was maintained within the
temperature range of 45 to 55C. Polymerization of the
butadiene was completed in about 50 minutes. The reaction
mixture was then cooled to about 35C and 22 milliliters of
styrene were added. The solution was stirred for about two
minutes and 2 milliliters of distilled tetrahydrofuran were
added. The temperature of the solution was maintained at
about 35C for a period of about one hour, and 0.15 milli-
- liters of glacial acetic acid added. The reaction mixture
~ '
17,753B-F 12-
~9~ 3
was diluted by the addition of methanol which caused pre-
cipitation of the polymer formed~ The precipitate was
separated from the liquid and vacuum dried at room temperature
overnight. A portion of the polymer was compression molded
in test bars at a temperature of about 180C. The polymer
had a tensile strength at bxeak of 3245 lb. per square inch
(227 kg/sq.cm) as measured at 23C and a jaw separation
rate of 20 inches (50.3 cms) per minute. The elongation
at break of the polymer sample was 1000 percent. The
molecular weight of the polymer was determined by gel-
-permeation chromatography by the ~ethod described in the
J. A~pl ed Polym. Sci. 13, 2359 (1969) Runyon et al. The
molecular weight was 123,000 with a central block of
butadiene of 83,000 and two styrene-end blocks of 20 t ;~
each.
Example 3
A reaction flask was purged with nitrogen and
charged with 5~.5 grams of aluminum trichloride and 160
milliliters o benzene. A mixture of 40.6 grams of
terephthaloyl chloride in 280 milliliters of benzene was
added to the reaction flask from a dropping funnel over a
period of 50 minutes. The temperature of the reaction
mixture was maintained at about 44-47C for a period of
about 40 minutes and raised to 68C for about one and
one-half hours. The reaction vessel and contents were
cooled with ice water bath and ice water mixed with the
reaction mixture. Methylene chloride was added and the
aqueous and organic layers separated. The organic layer
was washed three times with aqueous sodium bicarbonate and
washed twice with water. The organic layer was dried over
17,153B-F -13-
~91~3
anhydrous sodium sulfate. The particulate sodium sulfate
separated and the organic solvents removed by evaporation.
The resultant crude product remaining after the evaporation
was recrystallized from absolute alcohol containing about
0.5 percent benzene. Thirty grams of 1,4-dibenzoylbenzene
were obtained which had a melting range of 155-160C~
The 1,4-dibenzoylbenzene was then converted to 1,4-
-bis(l-phenylethenyl)benzene (Compound VII), employing the
procedure set forth in Example 1 wherain Compound I was
converted to Compound II. A nitrogen-purged flask was
charged with 0.98 millimoles of Compound VII dissolved
in 20 milliliters of dry benzene. Subsequently, 6 milli-
liters of 0O483 Normal sec-butyllithium-hexane solution was
added. The mixture was stirred for 2 hours at room tempera-
ture. The mixture was a dark bluish red suspension and
contains Compound VIII, 1,4-phenylenebis(3-methyl-1-phenyl-
pentylidene)bis(lithium)l A portion of the solution
containing Compound VIII was acidified with glacial acetic
acid and the infrared spectrum showed no peak ln the 900
cm 1 region which indicated the absence of a vinyl group.
Butadiene was polymerized employiny the dispersion con-
; taining Compound VIII. A nitrogen-purged reaction 1ask
was charged with 450 milliliters of benzene and the dis-
p~rsion containing Compound VIII~ Ten grams of 1,3
; 25 -butadiene was added to the flask. The flask and contentswere maintained at a temperature of about 40~C for about
one~half hour, the dispersion became a solution and
`~ 28 grams of butadiene were added. The contents of the flask
were warmed to about 45-55C for a period of about 50
minutes. The reaction mixture and flask were then cooled
17,753B-F 14
a3L3
to room temperature and 2 milliliters of distilled tetra-
hydrofuran were added with stirring~ Subsequently, 1.12
milliequivalents of silicon tetrachloride in benzene were
added. Gels were immediately obvious. After about 60
minutes, 0 1 milliliter of glacial acetic acid was added.
The reaction mixture was stirred for 3a minutes. The
following day, the product was recovered by precipitation
by addition of methanol. The product contained 55 percent
gel. The theoretical gel content was 67 percent therefore the
initiator was difunctional.
Example 4
Compound IX, 4,4"-isopropylidenedibenzophenone
was prepared from 2,2-diphenylpropane and benzoylchloride
using the same reaction conditions as set forth in Example
I. The quantities of ingredients employed were: 2,2-
-diphenylpropane 20.8 grams t benzoylchloride 64.6 grams,
aluminum trichloride 61 grams, and l,2-dichloroethane 160
milliliters. The resultant diketone ~Compound IX) was
obtained as a viscous brown high boiling oil and showed
one main peak on a gas chromatogram. The infrared spec-
trum and the nuclear magnetic resona~ce spectru~ ~oth
indicated that the product was the desired diketone
(Compound IX). The above diketone ~Compound IX) was
subjected to the Wittig reaction employing conditions
set forth in Example 1 for the conversion of the diketone
to the corresponding diolefin compound to obtain
2,2-bis[4-(1-phenylethenyl)phenyl~propane (Compound
X). Compound X was obtained as a dark brown viscous
oil. The infrared spectrum and the nuclear magnetic
resonance spectrum both indicated that Compound X was
17,753B~F -15-
obtained. Examination in a gas chromatograph indicated
tha-t the material had a purity of over 90 percent. A
nitrogen-purged flask was charged with 2015 millimoles of
Compound X dissolved in 20 milliliters of benzeneO
Twelve milliliters of O.482 Normal sec-butyllithium in
n~hexane was added. The reactants all were at room
temperature. On addition of the sec-butyllithium solution,
the color of the mixture changed to a reddish brown and
suspended solids were slowly formed. The solution then
contained Compound XI, (l-methylethylidene)bis [4rl-
-phenylene(3~methyl-1-phenylpentylidene)]bis(lithium).
After the reaction mixture was agitated at room tempera-
ture for a period of 3 hours, it was employed as a poly-
merization initiator in the following manner: a nitrogen
flushed reaction vessel was charged with 500 milliliters
benzene, the dispersion containincJ Compound XI and 10
grams of 1,3-butadiene. After a period of about one and
one-half hours at which time 45 grams of butadlene were
added, the mixture was maintained at a temperature of
about 45-50C and was cooled to room temperature after
about 70 minutes. On cooling 6.5 milliliters of distilled
tetrahydro~uran were added. On completion of the addition
of tetrahydrofuran, and a short period of stirring 2.79
milliequivalents of silicon tetrachloride in benzene
were added. On the addition of the silicon tetrachloride,
gels became immediately obvious. The mixture was allowed
to stand for about 20 minutes and 0.8 milliliters of
glacial acetic acid was added and the mixture allowed to
stand overnight. The following day, the polymer was
recovered by precipitating with methanol and the resulting
17~753B F -16-
~ ~19~3
product found contained greater than 90 percent gel~
Presence of gel indicated the diEunctionali~y of the
initiator.
Examp e 5 Preparation of t-Butylstyrene-Styrene-
-t-Butylstyrene Triblock Copolymer
To a nitrogen filled 1 liter flask 450 ml
of degassed dry benzene and 55 ml of purified styrene
were added. The residue impurities in the mixture
were removed by titrating with a sec-butyllithium in
cyclohexane solution (0.56 N) until a faint straw
color appeared. A total of 0.31 milliequivalent of
sec-butyllithium was used. To this mixture 2 ml of
purified tetrahydrofuran and 0.394 millimole of compound
IV as prepared in Example 2 were added. The reaction
mixture turned immediately to a deep orange brown color ~r
and heat began to evolve. After 60 minutes the flask
was cool again. An additional 30 minutes was allowed
to insure that all styrene monomers were reacted. Puri-
fied t-butylstyreney 2.9 ml, was then added to the
reaction flask containing the difunctional living poly-
styrene anions. Polymerization of t-butylstyrene was
allowed to continue for another 60 minutes before a 0.5
ml portion of glacial acetic acid was added to terminate
the living dianions. The polymer recovered by the usual
precipitation and drying technique was quantitative
indicating that all monomers added were used.
Example 6 Preparation of ar ~-dihydroxypolybutadiene
Ethylene oxide, approximatPly 2 ml~ was con-
densed from a cylinder into a 50 ml vial equipped with
a high vacuum stopcock and a rubber septum capped side
arm. To this condensed ethylene oxide liquid 4 drops
17,753B-F -17-
of a y-butyllithium (1. 5 N in hexane) solution was
added to react with the impurities which might be pre-
sent. The vial containing the condensed ethylene oxide
was then attached to a side arm of a 1 liter reaction
flask.
The reaction flask was -then filled with N2
degassed dry benzene and approximately 25 g of purified
butadiene monomer. The residue inpurities in this reac-
tion mixture were removed by the addition of 0.42 milli-
equivalent of a sec-butyllithium in cyclohexane solution.
To this purified reaction mixture, 0.56 milli-
mole of compound IV as prepared in Example 2 was added.
The reaction mixture was heated to 55C. Polymerization
~ was allowed to continue at this temperature for about
-! 15 60 minutes. At the end of the reaction period, the 55C
water bath was removed, 2 ml of purified tetrahydrofuran
was added. A reduction of viscosity was observed. After
5 more minutes of continuous agitation, the stopcock
connecting the condensed ethylene oxide vial and the
polymerization flask was opened. The dry ice-methylene
chloride mixture which was used to keep the ethylene oxide
in the vial condensed was also removed. A beaker of hot
water was then used to hasten the vaporization of the
ethylene oxide. The viscosity of the liquid in the
polymerization flask increased now rapidly and the straw
yellow color of the polybutadlenyl dianions started to
fade. After about 4 minutes the color disappeared almost
completely and the entire solution gelled up~ Agitation
was now stopped. The gel was allowed to stand for 15
more minutes before a 1 ml portion of glacial acetic acid
17~753B-F -18-
~:
was added. The gel structure disappeared into a normal
viscosity liquid immediately upon the addition of the
acetic acidO This appearance and disappearance of the
gel structure indicated that the capping reaction to
produce the +Li O ~ O Li+ dianions by ethylene oxide was
essentially complete and the subsequent acidification
produced the desired a,~-dihydroxypolybutadiene.
Initiators in accordance with the present invention
are readily prepared in situ by maintaining a supply of the
corresponding divinylidene compound. The divinylidene compound
is readily and quickly converted to the corresponding lithium
compound and solubilized by the addition of small quantities ;
of monomer such as butadiene. If desired, the entire system
can avoid the addition of polar compounds such as ethers
or amines and thus when employed the polymerization of
diene polymers 1,2 addition is minimized; however, if it is
- desired, appropriate polar compounds may be added to increase
1,2 addition, to increase the rate of polymerization and
to reduce the viscosity of the reaction mixture~
17,753B-F -19-
