U.S. patent application number 14/344001 was filed with the patent office on 2014-07-31 for bis-imine pyridine complex of lanthanides catalytic system comprising said bis-imine pyridine complex and process for the (co)polymerization of conjugated dienes.
The applicant listed for this patent is Versalis S.P.A.. Invention is credited to Aldo Boglia, Maria Caldararo, Giuseppe Leone, Francesco Masi, Giovanni Ricci, Anna Sommazzi.
Application Number | 20140213433 14/344001 |
Document ID | / |
Family ID | 44907949 |
Filed Date | 2014-07-31 |
United States Patent
Application |
20140213433 |
Kind Code |
A1 |
Ricci; Giovanni ; et
al. |
July 31, 2014 |
BIS-IMINE PYRIDINE COMPLEX OF LANTHANIDES CATALYTIC SYSTEM
COMPRISING SAID BIS-IMINE PYRIDINE COMPLEX AND PROCESS FOR THE
(CO)POLYMERIZATION OF CONJUGATED DIENES
Abstract
A bis-imine pyridine complex of lanthanides having general
formula (I): Said bis-imine pyridine complex of lanthanides having
general formula (I) can be advantageously used in a catalytic
system for the (co)polymerization of conjugated dienes.
##STR00001##
Inventors: |
Ricci; Giovanni; (Parma,
IT) ; Sommazzi; Anna; (Novara, IT) ; Leone;
Giuseppe; (Milano, IT) ; Boglia; Aldo;
(Milano, IT) ; Masi; Francesco; (Sant'Angelo
Lodigiano (LO), IT) ; Caldararo; Maria; (Trecate
(Novara), IT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Versalis S.P.A. |
San Donato Milanese |
|
IT |
|
|
Family ID: |
44907949 |
Appl. No.: |
14/344001 |
Filed: |
September 13, 2012 |
PCT Filed: |
September 13, 2012 |
PCT NO: |
PCT/EP2012/067992 |
371 Date: |
March 10, 2014 |
Current U.S.
Class: |
502/154 ;
534/15 |
Current CPC
Class: |
C08F 136/00 20130101;
C08F 36/04 20130101; C08F 36/08 20130101; C08F 36/00 20130101; C08F
2410/04 20130101; C08F 36/06 20130101; C08F 36/00 20130101; C08F
4/545 20130101 |
Class at
Publication: |
502/154 ;
534/15 |
International
Class: |
C08F 36/04 20060101
C08F036/04 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 14, 2011 |
IT |
MI2011A001651 |
Claims
1. A bis-imine pyridine complex of lanthanides having general
formula (I): ##STR00021## wherein: Ln represents a metal of the
series of lanthanides; R.sub.1 and R.sub.2, equal to or different
from each other, represent a hydrogen atom; or they are selected
from linear or branched C.sub.1-C.sub.20 alkyl groups, cycloalkyl
groups optionally substituted, aryl groups optionally substituted;
R.sub.3 and R.sub.4, equal to or different from each other,
represent a hydrogen atom; or they are selected from linear or
branched C.sub.1-C.sub.20 alkyl groups, cycloalkyl groups
optionally substituted, aryl groups optionally substituted; or
R.sub.2 and R.sub.4 can be optionally bound to each other so as to
form, together with the other atoms to which they are bound, a
saturated, unsaturated or aromatic cycle containing from 3 to 6
carbon atoms, optionally substituted with linear or branched
C.sub.1-C.sub.20 alkyl groups, said cycle optionally containing
other heteroatoms such as oxygen, sulfur, nitrogen, silicon,
phosphorous, selenium; or R.sub.1 and R.sub.3 can be optionally
bound to each other so as to form, together with the other atoms to
which they are bound, a saturated, unsaturated or aromatic cycle
containing from 3 to 6 carbon atoms, optionally substituted with
linear or branched C.sub.1-C.sub.20 alkyl groups, said cycle
optionally containing other heteroatoms; and X.sub.1, X.sub.2 and
X.sub.3, equal to or different from each other, represent a halogen
atom; or they are selected from linear or branched C.sub.1-C.sub.20
alkyl groups, --OCOR.sub.5 or --OR.sub.5 groups wherein R.sub.5 is
selected from linear or branched C.sub.1-C.sub.20 alkyl groups.
2. The bis-imine pyridine complex of lanthanides having general
formula (I) according to claim 1, wherein Ln represents neodymium
(Nd), lanthanum (La), praseodymium (Pr), gadolinium (Gd), europium
(Eu), terbium (Tb), samarium (Sm), erbium (Er), or ytterbium
(Yb).
3. The bis-imine pyridine complex of lanthanides having general
formula (I) according to claim 1, wherein: Ln is neodymium (Nd),
praseodymium (Pr), gadolinium (Gd), or lanthanum (La); R.sub.1 and
R.sub.2, the same as each other, are a hydrogen atom; or they are
selected from linear or branched C.sub.1-C.sub.20 alkyl groups; or
they are selected from cycloalkyl groups optionally substituted;
R.sub.3 and R.sub.4, equal to or different from each other, are
selected from phenyl groups, optionally substituted; or they are
selected from cycloalkyl groups optionally substituted; X.sub.1,
X.sub.2 and X.sub.3, the same as each other, are a halogen
atom.
4. A catalytic system for the (co)polymerization of conjugated
dienes comprising: (a) at least one bis-imine pyridine complex of
lanthanides having general formula (I) according to claim 1; (b) at
least one co-catalyst selected from: (b1) aluminium alkyls having
general formula (II): Al(X').sub.n(R.sub.6).sub.3-n (II) wherein X'
represents a halogen atom; R.sub.6 is selected from linear or
branched C.sub.1-C.sub.20 alkyl groups, C.sub.3-C.sub.20 cycloalkyl
groups, aryl groups, said groups being optionally substituted with
one or more atoms of silicon or germanium; and n is an integer
ranging from 0 to 2; (b2) aluminium oxanes having general formula
(III):
(R.sub.7).sub.2--Al--O--[--Al(R.sub.8)--O--].sub.p--Al--(R.sub.9).sub.2
(III) wherein R.sub.7, R.sub.8 and R.sub.9, equal to or different
from each other, represent a hydrogen atom, a halogen atom; or they
are selected from linear or branched C.sub.1-C.sub.20 alkyl groups,
C.sub.3-C.sub.20 cycloalkyl groups, aryl groups, said groups being
optionally substituted with one or more atoms of silicon or
germanium; and p is an integer ranging from 0 to 1,000; and (b3)
compounds having general formula (IV): D.sup.+E.sup.- (IV) wherein
D.sup.+ represents a Bronsted acid capable of releasing a proton
and of reacting irreversibly with the substituent X of the
bis-imine pyridine complex of lanthanides having general formula
(I); E.sup.- represents a compatible anion capable of stabilizing
the active catalytic species generated by the reaction of the two
components and which is sufficiently labile as to be removed by an
olefin monomer, or an anion having general formula
B(Ar).sub.4.sup.(-) wherein the substituents Ar, equal to or
different from each other, are selected from aryl groups.
5. The catalytic system for the (co)polymerization of conjugated
dienes according to claim 4, wherein said co-catalyst (b) is
selected from: tri-iso-butyl-aluminum (TIBA),
di-iso-butyl-aluminium hydride (DIBAH), methylaluminumoxane (MAO),
or tetra-iso-butyl-aluminumoxane (TIBAO).
6. The catalytic system for the (co)polymerization of conjugated
dienes according to claim 4, wherein in said catalytic system the
molar ratio between the lanthanide present in the bis-imine
pyridine complex of lanthanides (a) having general formula (I) and
the aluminium present in the co-catalyst (b) selected from
aluminium alkyls (b.sub.1) or aluminumoxanes (b2), ranges from 5 to
5,000.
7. The catalytic system for the (co)polymerization of conjugated
dienes according to claim 4, wherein in said catalytic system the
molar ratio between the lanthanide present in the bis-imine
pyridine complex of lanthanides (a) having general formula (I) and
the boron present in the co-catalyst (b) selected from compounds
(b.sub.3) having general formula (IV), ranges from 0.1 to 15.
8. (canceled)
9. The catalytic system according to claim 1, wherein said
conjugated dienes are 1,3-butadiene, isoprene.
10-12. (canceled)
Description
[0001] The present invention relates to a bis-imine pyridine
complex of lanthanides.
[0002] More specifically, the present invention relates to a
bis-imine pyridine complex of lanthanides and its use in a
catalytic system for the (co)polymerization of conjugated
dienes.
[0003] The present invention also relates to a catalytic system for
the (co)polymerization of conjugated dienes comprising said
bis-imine pyridine complex of lanthanides.
[0004] Furthermore, the present invention relates to a
(co)polymerization process of conjugated dienes, in particular a
process for the polymerization of 1,3-butadiene or isoprene,
characterized in that it uses said catalytic system.
[0005] It is known that the stereospecific (co)polymerization of
conjugated dienes is an extremely important process in the chemical
industry for obtaining products which are among the most
widely-used rubbers.
[0006] It is known, for example, that polybutadiene 1,4-cis is a
synthetic elastomer whose properties are very similar to those of
natural rubber. Since the beginning of stereospecific
polymerization, numerous catalytic systems have been used for the
production of this elastomer, as described, for example, by Porri
L. et al. in: "Comprehensive Polymer Science" (1989), Eastmond G.
C. et al. Eds., Pergamon Press, Oxford, UK, Vol. 4, Part II, pages
53-108.
[0007] A first catalytic system capable of giving a polybutadiene
having a 1,4-trans content ranging from 70% to 90% is described in
U.S. Pat. No. 3,050,513 and was based on titanium compounds
containing iodine, such as titanium tetraiodide (TiI.sub.4),
combined with an aluminium hydride such as, for example,
lithium-aluminium hydride, sodium-aluminium hydride,
potassium-aluminium hydride, rubidium-aluminium hydride,
caesium-aluminium hydride.
[0008] Efforts were then made in the art to find catalytic systems
capable of giving polybutadiene having a high content of 1,4-cis
units.
[0009] Catalytic systems capable of giving a polybutadiene having a
1,4-cis content equal to about 93% are described, for example, by
W. Cooper in "The Stereo Rubbers" (1977), Ed. W. M. Saltman, Wiley,
New York, page (catalytic system: AliBu.sub.3-TiI.sub.4); W.
Marconi et al., in "Chimica Industriale" (1963), Vol. 45, page 522
(catalytic system: AlEt.sub.3-AlEt.sub.2I--TiCl.sub.4); W. Marconi
et al., in "Journal of Polymer Science" (1965), Part A, Vol. 3,
page 735 (catalytic system:
AlHCl.sub.2.OEt.sub.2-TiCl.sub.4--AlI.sub.3).
[0010] The formation of catalytic systems characterized by a higher
stereospecificity capable of giving polybutadiene having a content
of 1,4-cis units equal to about 96%, is described, for example:
with respect to catalytic systems comprising cobalt, in Italian
patent IT 592,477 and by Gippin M. et al. in "Industrial &
Engineering Chemistry, Product Research and Development" (1962),
Vol. 1(1), pages 32-39; with respect to catalytic systems
comprising nickel, by Ueda et. al., in "Koogyo Kagaku Zasshi"
(1963), Vol. 66, page 1103, and by Throckmorton et al. in "Rubber
Chemistry and Technology" (1972), Vol. 45, pages 268-277.
[0011] Some works relating to the use of catalytic systems
comprising lanthanides for the 1,4-cis polymerization of conjugated
dienes were published in the first half of the sixties'.
[0012] Saltman et al. in "Rubber Chemistry and Technology" (1973),
Vol. 46, page 1055 and Throckmorton et al. in "Kautschuk and Gummi
Kunstoffe" (1969), Vol. 22, page 293, for example, describe the use
of catalytic systems comprising cerium. These catalytic systems,
however, were soon abandoned as a result of the metal residues
remaining in the polymer which caused an oxidation of the polymer
itself.
[0013] The use of catalytic systems comprising lanthanides such as,
for example, neodymium, praseodymium and gadolinium, is also known,
as described, for example, by: Hsieh H. L. et al. in "Rubber
Chemistry and Technology" (1985), Vol. 58(1), pages 117-145. The
polybutadiene obtained using these catalytic systems has a content
of 1,4-cis units of about 98%, a good processability, and a
relatively large molecular weight distribution.
[0014] The use is also known of catalytic systems comprising
uranium allyls capable of providing a polybutadiene having a very
high content of 1,4-cis units (i.e. 99%) as described, for example,
by Lugli et al. in "Die Makromoleculare Chemie" (1974), Vol. 175,
Issue 7, pages 2021-2027; De Chirico A. et al. in "Die
Makromoleculare Chemie" (1974), Vol. 175, Issue 7, pages 2029-2038;
Bruzzone M. et al. in "Rubber Chemistry and Technology" (1974),
Vol. 47, page 1175; Mazzei A. in "Die Makromoleculare Chemie"
(1981), Vol. 4, Issue Supplement 3, pages 61-72. These catalytic
systems, however, were also abandoned due to the presence of
radioactive residues in the polymers obtained.
[0015] From the above documents it emerges, however, that the use
of catalytic systems comprising lanthanides offered advantages with
respect to the use of catalysts based on titanium, cobalt and
nickel, previously proposed and in use at that time. In particular,
catalytic systems comprising lanthanides, as mentioned above, were
capable of giving polymers, in particular polybutadiene, having a
higher content of 1,4-cis units 97%), with a more linear structure
and, consequently, more suitable for the production of tyres, which
represents the most important application (about 80%) of
polybutadiene 1,4-cis use. Furthermore, the above catalytic systems
comprising lanthanides did not have a cationic activity and proved
to have a higher activity when used in solution polymerization in
the presence of aliphatic solvents rather than aromatic solvents,
as described, for example, by Ricci G. et al., in "Die
Makromoleculare Chemie", Rapid Communications, (1986), Vol. 7, page
335.
[0016] Further studies were then carried out with the aim of
finding new catalytic systems comprising lanthanides and/or of
improving the catalytic activity of already known catalytic
systems.
[0017] In particular, studies were mainly carried out on catalytic
systems comprising neodymium as these catalytic systems had a
higher catalytic activity with respect to catalytic systems
comprising other lanthanides and they were capable of providing
polymers which, after vulcanization, had a higher resistance to
aging with respect to the polymers obtained with catalytic systems
comprising titanium, cobalt and nickel. Furthermore, these studies
were also supported by the great availability, at a low price, of
the precursors, including neodymium.
[0018] European patent EP 0 076 535, for example, describes an
enhanced process for the (co)polymerization of conjugated diolefins
comprising the use of a particular catalytic system including at
least one compound of a metal selected from those of Group III B of
the Periodic System having an atomic number between 21 and 103,
preferably neodymium, a derivative of an organic halide and an
organometallic compound containing aluminium such as, for example,
alkyl aluminium hydride, or trialkyl aluminium hydride. Said
process allows (co)polymers having a high content of 1,4-cis units
(>98%) and a high linearity, to be obtained.
[0019] U.S. Pat. No. 4,242,232 describes a catalyst comprising (a)
a reaction mixture formed by reacting a carboxylate of a metal
having an atomic number ranging from 57 to 71 such as, for example,
lanthanum, cerium, praseodymium, neodymium with an aluminium
tri-alkyl, (b) an aluminium alkyl and/or an aluminium alkyl hydride
and (c) a Lewis acid. The polybutadiene obtained by using said
catalyst has a content of 1,4-cis ranging from 80 to 99%.
[0020] In their simplest form, the catalytic systems comprising
neodymium are obtained by reaction between neodymium trichloride,
as such or complexed with donors (e.g. alcohols, ethers,
tri-butyl-phosphate, alkylsulfoxides, amides, pyridine), and an
aluminium tri-alkyl (e.g. aluminium tri-iso-butyl, aluminium
tri-ethyl, aluminium tri-methyl): in this case, these are binary
catalytic systems. Said binary catalytic systems are described, for
example, by Yang J. H. et al., in "Macromolecules" (1982), Vol.
15(2), pages 230-233; Porri L. et al. in "Macromolecular Symposia"
(1998), Vol. 128, Issue 1, pages 53-61.
[0021] Alternatively, neodymium chloride can be obtained by
reaction of a neodymium compound (e.g., alcoholate, carboxylate)
with a chlorine donor (e.g., di-ethyl aluminium chloride,
ethyl-aluminium dichloride, bisaluminium tri-ethyl trichloride,
t-butyl chloride) and then reacted with an aluminium alkyl or an
aluminium tri-alkyl: in this case, these are tertiary catalytic
systems. Said tertiary catalytic systems are described, for
example, by: Cabassi F. et al. in "Transition Metal Catalyzed
Polymerizations" (1988), Quirk R. P. Ed., Cambridge University
Press, MA, USA, pages 655-670; Ricci G. et al. in "Polymer
Communications Guilford" (1987), Vol. 28, Issue 8, pages 223-226;
or in Italian patent IT 1,197,465.
[0022] The order for adding the components (chlorine donor,
aluminium alkyl or aluminium tri-alkyl) to the neodymium compound
can be extremely important for the nature of the catalytic system
to be obtained. By first adding aluminium alkyl hydride or
aluminium tri-alkyl and only subsequently the chlorine donor, in
fact, homogeneous catalysts are obtained; vice versa, when the
chlorine donor is added before the aluminium alkyl hydride or the
aluminium tri-alkyl, heterogeneous systems are obtained, as
described, for example, by Porri et al. in "ACS Symposium Series"
(2000), Vol. 749, Chapter 2, pages 15-30. The order of adding the
above-mentioned components, is also decisive for the catalytic
activity and for the polydispersity of the resulting polymers.
[0023] In the binary and ternary catalytic systems mentioned above,
however, the percentage of neodymium catalytically active is
relatively low, normally ranging from 7% to 8% (said percentage
referring to the molar percentage of active neodymium with respect
to the total moles of neodymium charged), as described, for
example, by Marina N. G. et al., in "Doklady Akademii Nauk SSSR"
(1982), Vol. 265, pages 1431-1433.
[0024] Much more active ternary catalytic systems, containing a
higher percentage of catalytically active neodymium, have been
obtained by reaction between allyl compounds of neodymium, obtained
by reaction between the complex of neodymium chloride with
tetrahydrofuran (THF) and allyl Grignard, and aluminium alkyl [e.g.
aluminium trialkyl, methylaluminoxane (MAO),
tetra-isobutyl-aluminoxane (TIBAO)], as described, for example, in
Italian patent IT 1,228,442; or by: Porri L. et al. in
"Macromolecular Symposia" (1993), Vol. 66, pages 231-244; Porri L.
et al. in "Polymer Preprints", "American Chemical Society Division
Polymer Chemistry" (1998), Vol. 39, pages 214-215; Porri L. in
"Recent developments in Lanthanide catalysts for 1,3-diene
polymerization", in "ACS Symposium Series 749--Olefin
Polymerization: Emerging Frontiers" (2000), P. Arjunan, J. C.
McGrath and T. Hanlon Eds., Oxford University Press, USA, pages
15-30. Said ternary catalytic systems provide a polybutadiene
having a much lower polydispersity than those obtained by means of
the classical ternary catalytic systems mentioned above.
Furthermore, said ternary catalytic systems can also produce
polyisoprene and/or other polymers deriving from the
(co)polymerization of substituted butadienes, providing
(co)polymers with a high content of 1,4-cis units (i.e.
content.gtoreq.90%). In particular, a polymer is obtained from the
polymerization of isoprene, having a content of 1,4-cis units equal
to about 94%, which can be advantageously used for producing
elastomeric blends for the production of tyres.
[0025] As mentioned above, due to the fact that the (co)polymers of
conjugated dienes, in particular polybutadiene and polyisoprene,
with a high content of 1,4-cis units, are the most widely used on
an industrial scale, in particular for the production of tyres, the
study of new catalytic systems capable of providing said
(co)polymers, is still of great interest.
[0026] The Applicant has faced the problem of finding a new
bis-imine pyridine complex of lanthanides that can be used in a
catalytic system capable of providing (co)polymers of conjugated
dienes, in particular polybutadiene and polyisoprene, linear or
branched, with a high content of 1,4-cis units, i.e. a content of
1,4-cis units 99% in the case of polybutadiene, and 98% in the case
of polyisoprene. Furthermore, said polyisoprene has a glass
transition temperature (TO similar to that of natural rubber.
[0027] An object of the present invention therefore relates to a
bis-imine pyridine complex of lanthanides having general formula
(I):
##STR00002##
wherein: [0028] Ln represents a metal of the series of lanthanides,
preferably selected from neodymium (Nd), lanthanum (La),
praseodymium (Pr), gadolinium (Gd), europium (Eu), terbium (Tb),
samarium (Sm), erbium (Er), ytterbium (Yb); [0029] R.sub.1 and
R.sub.2, equal to or different from each other, represent a
hydrogen atom; or they are selected from linear or branched
C.sub.1-C.sub.20, preferably C.sub.1-C.sub.15, alkyl groups,
cycloalkyl groups optionally substituted, aryl groups optionally
substituted; [0030] R.sub.3 and R.sub.4, equal to or different from
each other, represent a hydrogen atom; or they are selected from
linear or branched C.sub.1-C.sub.20, preferably C.sub.1-C.sub.15,
alkyl groups, cycloalkyl groups optionally substituted, aryl groups
optionally substituted; [0031] or R.sub.2 and R.sub.4 can be
optionally bound to each other so as to form, together with the
other atoms to which they are bound, a saturated, unsaturated or
aromatic cycle containing from 3 to 6 carbon atoms, optionally
substituted with linear or branched C.sub.1-C.sub.20, preferably
C.sub.1-C.sub.15, alkyl groups, said cycle optionally containing
other heteroatoms such as, for example, oxygen, sulfur, nitrogen,
silicon, phosphorous, selenium; [0032] or R.sub.1 and R.sub.3 can
be optionally bound to each other so as to form, together with the
other atoms to which they are bound, a saturated, unsaturated or
aromatic cycle containing from 3 to 6 carbon atoms, optionally
substituted with linear or branched C.sub.1-C.sub.20, preferably
C.sub.1-C.sub.15, alkyl groups, said cycle optionally containing
other heteroatoms such as, for example, oxygen, sulfur, nitrogen,
silicon, phosphorous, selenium; [0033] X.sub.1, X.sub.2 and
X.sub.3, equal to or different from each other, represent a halogen
atom such as chlorine, bromine, iodine; or they are selected from
linear or branched C.sub.1-C.sub.20, preferably C.sub.1-C.sub.15,
alkyl groups, --OCOR.sub.5 or --OR.sub.5 groups wherein R.sub.5 is
selected from linear or branched C.sub.1-C.sub.20, preferably
C.sub.1-C.sub.15, alkyl groups.
[0034] For the aim of the present description and of the following
claims, the definitions of the numerical intervals always include
the extremes, unless otherwise specified
[0035] For the aim of the present description and of the following
claims, the term "metal belonging to the family of lanthanides"
means any metal belonging to the Periodic Table of Elements having
an atomic number ranging from 57 to 71.
[0036] It should be noted that, for the aim of the present
invention and of the following claims, the term "Periodic Table of
the Elements" refers to the IUPAC version of the "Periodic Table of
the Elements" dated Jun. 22, 2007, provided in the following
Internet website www.iupac.org/reports/periodic_table.
[0037] The term "C.sub.1-C.sub.20 alkyl groups" refers to linear or
branched alkyl groups having from 1 to 20 carbon atoms. Specific
examples of C.sub.1-C.sub.20 alkyl groups are: methyl, ethyl,
n-propyl, iso-propyl, n-butyl, sec-butyl, iso-butyl, tert-butyl,
pentyl, hexyl, heptyl, octyl, nnonyl, n-decyl, 2-butyloctyl,
5-methylhexyl, 4-ethylhexyl, 2-ethylheptyl, 2-ethylhexyl.
[0038] The term "cycloalkyl groups" refers to cycloalkyl groups
having from 3 to 30 carbon atoms. Said cycloalkyl groups can be
optionally substituted with one or more groups, equal to or
different from each other, selected from: halogen atoms; hydroxyl
groups; C.sub.1-C.sub.12 alkyl groups; C.sub.1-C.sub.12 alkoxyl
groups; cyano groups; amino groups; nitro groups. Specific examples
of cycloalkyl groups are: cyclopropyl, 2,2-difluorocyclopropyl,
cyclobutyl, cyclopentyl, cyclohexyl, hexamethylcyclohexyl,
pentamethylcyclopentyl, 2-cyclooctylethyl, methylcyclohexyl,
methoxycyclohexyl, fluorocyclohexyl, phenylcyclohexyl.
[0039] The term "aryl groups" means aromatic carbocyclic groups.
Said aromatic carbocyclic groups can be optionally substituted with
one or more groups, equal to or different from each other, selected
from: halogen atoms such as, for example, fluorine, chlorine,
bromine, preferably fluorine; hydroxyl groups; C.sub.1-C.sub.12
alkyl groups; C.sub.1-C.sub.12 alkoxyl groups, cyano groups; amino
groups; nitro groups. Specific examples of aryl groups are: phenyl,
methylphenyl, trimethylphenyl, methoxyphenyl, hydroxyphenyl,
phenyloxyphenyl, fluorophenyl, pentafluorophenyl, chlorophenyl,
bromophenyl, nitrophenyl, dimethylaminophenyl, naphthyl,
phenylnaphthyl, phenanthrene, anthracene.
[0040] The term "cyclo" relates to a system containing a ring
containing from 3 to 6 carbon atoms, optionally also containing, in
addition to the nitrogen atom, other heteroatoms selected from
nitrogen, oxygen, sulfur, silicon, selenium, phosphorous. Specific
examples of cyclo are: pyridine, thiadiazole.
[0041] According to a preferred embodiment of the present
invention, in said bis-imine pyridine complex of lanthanides having
general formula (I): [0042] Ln is neodymium (Nd), praseodymium
(Pr), gadolinium (Gd), lanthanum (La), preferably neodymium (Nd);
[0043] R.sub.1 and R.sub.2, the same as each other, are a hydrogen
atom; or they are selected from linear or branched C.sub.1-C.sub.20
alkyl groups, and are preferably a methyl group; or they are
selected from cycloalkyl groups optionally substituted; [0044]
R.sub.3 and R.sub.4, equal to or different from each other, are
selected from phenyl groups optionally substituted; or they are
selected from cycloalkyl groups optionally substituted; [0045]
X.sub.1, X.sub.2 and X.sub.3, the same as each other, represent a
halogen atom such as chlorine, bromine, iodine, preferably
chlorine.
[0046] The bis-imine pyridine complex of lanthanides having general
formula (I) is intended, according to the present invention, as
being in any physical form such as, for example, isolated and
purified solid form, solvated form with a suitable solvent, or
supported on suitable organic or inorganic solids, preferably
having a physical granular or powder form.
[0047] The bis-imine pyridine complex of lanthanides having general
formula (I) is prepared starting from ligands known in the art.
[0048] Specific examples of ligands which can be used for the aim
of the present invention are those having the following formulae
(L1)-(L8):
##STR00003## ##STR00004##
[0049] Said ligands having formulae (L1)-(L8), can be prepared by
means of processes known in the art. Said ligands having formulae
(L1)-(L8) can be prepared, for example, by means of condensation
reactions between primary amines and diketones as described, for
example, in International patent applications WO 2002/10133 and WO
2002/34701.
[0050] The bis-imine pyridine complex of lanthanides having general
formula (I) can be prepared according to processes known in the art
for the preparation of analogous complexes of other metals such as,
for example, cobalt, nickel. Said bis-imine pyridine complex of
lanthanides can be prepared, for example, by reaction between
compounds of lanthanides having general formula Ln(X).sub.3 wherein
Ln and X have the same meanings described above, as such or
complexed with ethers [for example, diethyleter, tetrahydrofuran
(THF), dimethoxyethane], with ligands having formulae (L1)-(L8)
indicated above, in a molar ratio ligand (L)/lanthanide (Ln)
ranging from 1 to 1.5, preferably operating in the presence of at
least one ether solvent [for example, tetrahydrofuran (THF)], at
room temperature or higher. The bis-imine pyridine complex of
lanthanides thus obtained can be subsequently recovered by means of
methods known in the art such as, for example, precipitation by
means of a non-solvent (for example pentane), followed by
separation by filtration or decanting and optional subsequent
solubilization in a suitable solvent followed by low-temperature
crystallization.
[0051] For the aim of the present description and of the following
claims, the phrase "room temperature" means a temperature ranging
from 20.degree. C. to 25.degree. C.
[0052] As specified above, the present invention also relates to a
catalytic system for the (co)polymerization of conjugated dienes
comprising said bis-imine pyridine complex of lanthanides having
general formula (I).
[0053] A further object of the present invention therefore relates
to a catalytic system for the (co)polymerization of conjugated
dienes comprising: [0054] (a) at least one bis-imine pyridine
complex of lanthanides having general formula (I); [0055] (b) at
least one co-catalyst selected from: [0056] (b.sub.1) aluminium
alkyls having general formula (II):
[0056] Al(X').sub.n(R.sub.6).sub.3-n (II) wherein X' represents a
halogen atom such as, for example, chlorine, bromine, iodine,
fluorine; R.sub.6 is selected from linear or branched
C.sub.1-C.sub.20 alkyl groups, C.sub.3-C.sub.20 cycloalkyl groups,
aryl groups, said groups being optionally substituted with one or
more silicon or germanium atoms; and n is an integer ranging from 0
to 2; (b.sub.2) aluminoxanes having general formula (III):
(R.sub.7).sub.2--Al--O--[--Al(R.sub.8)--O--].sub.p--Al--(R.sub.9).sub.2
(III) wherein R.sub.7, R.sub.8 and R.sub.9, equal to or different
from each other, represent a hydrogen atom, a halogen atom such as,
for example, chlorine, bromine, iodine, fluorine; or they are
selected from linear or branched C.sub.1-C.sub.20 alkyl groups,
C.sub.3-C.sub.20 cycloalkyl groups, aryl groups, said groups being
optionally substituted with one or more silicon or germanium atoms;
and p is an integer ranging from 0 to 1000; [0057] (b.sub.3)
compounds having general formula (IV):
[0057] D.sup.+E.sup.- (IV) wherein D.sup.+ represents a Bronsted
acid capable of donating a proton and of reacting irreversibly with
the substituent X of the bis-imine pyridine complex of lanthanides
having general formula (I); E.sup.- represents a compatible anion
capable of stabilizing the active catalytic species which are
generated by the reaction of the two components and which is
sufficiently labile as to be able to be removed by an olefinic
monomer, preferably a boron atom, even more preferably an anion
having formula B(Ar).sub.4.sup.(-) wherein the substituents Ar,
equal to or different from each other, are selected from aryl
groups such as, for example, phenyl, pentafluorophenyl,
bis(trifluoromethyl)phenyl.
[0058] Specific examples of aluminium alkyls (b.sub.1) which are
particularly useful for the aim of the present invention are:
tri-methyl-aluminium, tri-(2,3,3-tri-methyl-butyl)-aluminium,
tri-(2,3-di-methyl-hexyl)aluminium,
tri-(2,3-di-methyl-butyl)-aluminium,
tri(2,3-di-methyl-pentyl)-aluminium,
tri-(2,3-di-methylheptyl)-aluminium,
tri-(2-methyl-3-ethyl-pentyl)aluminium,
tri-(2-methyl-3-ethyl-hexyl)-aluminium,
tri(2-methyl-3-ethyl-heptyl)-aluminium,
tri-(2-methyl-3-propyl-hexyl)-aluminium, tri-ethyl-aluminium,
tri-(2-ethyl-3-methyl-butyl)-aluminium,
tri-(2-ethyl-3-methylpentyl)-aluminium,
tri-(2,3-di-ethyl-pentyl-aluminium), tri-n-propyl-aluminium,
tri-iso-propyl-aluminium, tri(2-propyl-3-methyl-butyl)-aluminium,
tri-(2-iso-propyl-3-methyl-butyl)-aluminium, tri-n-butyl-aluminium,
triiso-butyl-aluminium (TIBA), tri-tert-butyl-aluminium,
tri-(2-iso-butyl-3-methyl-pentyl)-aluminium,
tri(2,3,3-tri-methyl-pentyl)-aluminium,
tri-(2,3,3-trimethyl-hexyl)-aluminium,
tri-(2-ethyl-3,3-di-methylbutyl)-aluminium,
tri-(2-ethyl-3,3-di-methyl-pentyl)aluminium,
tri-(2-iso-propyl-3,3-dimethyl-butyl)aluminium,
tri-(2-tri-methylsilyl-propyl)-aluminium,
tri-2-methyl-3-phenyl-butyl)-aluminium,
tri-(2-ethyl-3-phenyl-butyl)-aluminium,
tri-(2,3-di-methyl-3-phenylbutyl)-aluminium,
tri-(2-phenyl-propyl)-aluminium,
tri-[2-(4-fluoro-phenyl)-propyl]-aluminium,
tri-[2-(4-chloro-phenyl)-propyl]-aluminium,
tri-[2-(3-iso-propylphenyl-tri-(2-phenyl-butyl)-aluminium,
tri-(3-methyl-2-phenyl-butyl)-aluminium,
tri-(2-phenyl-pentyl)aluminium,
tri-[2-(penta-fluoro-phenyl)-propyl]-aluminium,
tri-(2,2-diphenyl-ethyl]-aluminium,
tri-(2-phenyl-methyl-propyl)-aluminium, tri-pentyl-aluminium,
tri-hexyl-aluminium, tri-cyclohexyl-aluminium, trioctyl-aluminium,
di-ethyl-aluminium hydride, di-npropyl-aluminium hydride,
di-n-butyl-aluminium hydride, di-iso-butyl-aluminium hydride
(DIBAH), di-hexylaluminium hydride, di-iso-hexyl-aluminium hydride,
dioctyl-aluminium hydride, di-iso-octyl-aluminium hydride,
ethyl-aluminium di-hydride, n-propyl-aluminium di-hydride,
iso-butyl-aluminium di-hydride, di-ethyl-aluminium chloride,
mono-ethyl-aluminium dichloride, di-methyl-aluminium chloride,
di-isobutyl-aluminium chloride, iso-butyl-aluminium dichloride,
ethyl-aluminium sesquichloride, and also the corresponding
compounds in which one of the hydrocarbon substituents is
substituted with a hydrogen atom and those in which one or two of
the hydrocarbon substituents are substituted with an iso-butyl
group. Tri-iso-butyl-aluminium (TIBA), di-iso-butyl-aluminium
hydride (DIBAH), are particularly preferred.
[0059] Specific examples of aluminoxanes (b.sub.2) which are
particularly useful for the aim of the present invention are:
methylaluminoxane (MAO), ethyl-aluminoxane, n-butyl-aluminoxane,
tetra-iso-butyl-aluminoxane (TIBAO), tert-butyl-aluminoxane,
tetra-(2,4,4-tri-methylpentyl)-aluminoxane (TIOAO),
tetra-(2,3-di-methylbutyl)-aluminoxane (TDMBAO),
tetra-(2,3,3-tri-methylbutyl)-aluminoxane (TDMBAO).
Methylaluminoxane (MAO), tetra-iso-butyl-aluminoxane (TIBAO), are
particularly preferred. Said aluminoxanes can be prepared according
to processes known in the art. Said aluminoxanes can be prepared,
for example, by reacting at least one trialkyl-aluminium or at
least one di-alkyl aluminium monochloride with water or with a salt
containing crystallization water such as, for example, copper
sulfate pentahydrate, aluminium sulfate hexadecahydrate, in the
presence of at least one organic solvent such as, for example,
benzene, toluene, xylene.
[0060] Specific examples of compounds (b.sub.3) having general
formula (IV) which are particularly useful for the aim of the
present invention are: tetrakispentafluorophenyl-borate
tributylammonium-tetrakispentafluorophenyl-aluminate,
tributylammonium-tetrakis-[(3,5-di-(trifluorophenyl)]-borate,
tributylammonium-tetrakis-(4-fluorophenyl)]-borate,
N,N-dimethylbenzylammonium-tetrakis-pentafluorophenyl-borate,
N,N-dimethyl-hexylammonium-tetrakis-pentafluorophenyl-borate,
N,N-dimethylanilinium-tetrakis-(pentafluorophenyl)borate,
N,N-dimethylanilinium-tetrakis(pentafluorophenyl)-aluminate,
di-(propyl)-ammoniumtetrakis-(pentafluorophenyl)-borate,
di-(cyclohexyl)ammonium-tetrakis-(pentafluorophenyl)-borate,
triphenyl-carbenium-tetrakis-(pentafluorophenyl)-borate,
tri-phenylcarbenium-tetrakis-(penta-fluorophenyl)aluminate.
Tetrakis-pentafluorophenyl-borate is preferred.
[0061] Alternatively, the compounds (b.sub.3) can be selected from
compounds having formula B(Ar).sub.3 wherein Ar has the same
meanings described above; or from compounds having formula
B(Ar).sub.3P wherein Ar has the same meanings described above and P
is a pyrrole radical optionally substituted.
[0062] Further details relating to aluminium alkyls (b.sub.1),
aluminoxanes (b.sub.2) and compounds (b.sub.2), can be found in
international patent application WO 2011/061151.
[0063] For the aim of the present description and of the following
claims, the term "moles" and "molar ratio" are used with reference
to compounds consisting of molecules and also with reference to
atoms and ions, omitting, for the latter, the terms gram atom or
atomic ratio, even if scientifically more correct.
[0064] According to a preferred embodiment of the present
invention, in said catalytic system, the molar ratio between the
lanthanide present in the bis-imine pyridine complex of lanthanides
(a) having general formula (I) and the aluminium present in the
co-catalyst (b) selected from aluminium alkyls (b.sub.1) or
aluminoxanes (b.sub.2), can range from 5 to 5,000, preferably from
10 to 1,000.
[0065] According to a preferred embodiment of the present
invention, in said catalytic system, the molar ratio between the
lanthanide present in the bis-imine pyridine complex of lanthanides
(a) having general formula (I) and the boron present in the
co-catalyst (b) selected from compounds (b.sub.3) having general
formula (IV), can range from 0.1 to 15, preferably from 0.5 to
10.
[0066] For the aim of the present invention, other additives or
components can be optionally added to the above catalytic system in
order to adapt it so as to satisfy specific practical requirements.
The catalytic systems thus obtained should therefore be considered
as being included in the scope of the present invention. Additives
and/or components which can be added in the preparation and/or
formulation of the catalytic system object of the present invention
are, for example, inert solvents, such as, for example, aliphatic
and/or aromatic hydrocarbons; aliphatic and/or aromatic ethers;
weakly coordinating additives (e.g. Lewis bases) selected, for
example, from non-polymerizable olefins; sterically hindered or
electronically poor ethers; halogenating agents such as, for
example, silicon halides, hydrogenated hydrocarbons, preferably
chlorinated; or mixtures thereof.
[0067] Said catalytic system can be prepared according to methods
known in the art.
[0068] Said catalytic system, for example, can be prepared
separately (preformed) and subsequently introduced into the
(co)polymerization environment. In this respect, said catalytic
system can be prepared by reacting at least one bis-imine pyridine
complex of lanthanides (a) having general formula (I) with at least
one co-catalyst (b), optionally in the presence of other additives
or components selected from those listed above, in the presence of
a solvent such as, for example, toluene, heptane, at a temperature
ranging from 20.degree. C. to 60.degree. C., for a time ranging
from 10 seconds to 10 hours, preferably from 30 seconds to 5 hours.
More details on the preparation of said catalytic system can be
found in the examples provided hereunder.
[0069] Alternatively, said catalytic system can be prepared in
situ, i.e. directly in the (co)polymerization environment. In this
respect, said catalytic system can be prepared by introducing the
bis-imine pyridine complex of lanthanides (a) having general
formula (I), the co-catalyst (b) and the preselected conjugated
diene(s) to be (co)polymerized, separately, operating under the
conditions in which the (co)polymerization is carried out.
[0070] For the aim of the present invention, the above catalytic
systems can also be supported on inert solids, preferably
consisting of silicon and/or aluminium oxides, such as, for
example, silica, alumina or silico-aluminates. The known supporting
techniques can be used for supporting said catalytic systems,
generally comprising the contact, in a suitable inert liquid
medium, between the carrier, optionally activated by heating to
temperatures higher than 200.degree. C., and one or both of
components (a) and (b) of the catalytic system object of the
present invention. For the aim of the present invention, it is not
necessary for both components to be supported, as the bis-imine
pyridine complex of lanthanides (a) having general formula (I)
only, or the co-catalyst (b) only, can be present on the surface of
the carrier. In the latter case, the missing component on the
surface is subsequently put in contact with the supported
component, at the moment in which the catalyst active for the
polymerization is to be formed.
[0071] The bis-imine pyridine complex of lanthanides having general
formula (I), and the catalytic systems based thereon, which have
been supported on a solid by the functionalization of the latter
and the formation of a covalent bond between the solid and the
bis-imine pyridine complex of lanthanides having general formula
(I), are also included in the aim of the present invention.
[0072] The present invention also relates to a process for the
(co)polymerization of conjugated dienes, characterized in that it
uses said catalytic system.
[0073] The quantity of bis-imine pyridine complex of lanthanides
(a) having general formula (I) and of co-catalyst (b) that can be
used in the (co)polymerization of conjugated dienes varies
according to the (co)polymerization process to be carried out. Said
quantity is in any case such as to obtain a molar ratio between the
lanthanide present in the bis-imine pyridine complex of lanthanides
(a) having general formula (I) and the metal present in the
co-catalyst (b), i.e. aluminium when the co-catalyst (b) is
selected from aluminium alkyls (b.sub.1) or aluminoxanes (b.sub.2),
boron when the co-catalyst (b) is selected from compounds (b.sub.3)
having general formula (IV), comprised within the values indicated
above.
[0074] Specific examples of conjugated dienes which can be
(co)polymerized using the catalytic system according to the present
invention are: 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene),
2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene,
cyclo-1,3-hexadiene. Preferred (co)polymerizable conjugated dienes
are 1,3-butadiene, isoprene. The above (co)polymerizable conjugated
dienes can be used alone, or in a mixture of two or more dienes. In
the latter case, i.e. using a mixture of two or more dienes, a
copolymer is obtained.
[0075] According to a particularly preferred embodiment, the
present invention relates to a polymerization process of
1,3-butadiene or isoprene, characterized in that it uses said
catalytic system.
[0076] Said (co)polymerization is generally carried out in the
presence of a polymerization solvent generally selected from inert
organic solvents such as, for example, saturated aliphatic
hydrocarbons such as, for example, butane, pentane, hexane,
heptane, or mixtures thereof; saturated cyclo-aliphatic
hydrocarbons such as, for example, cyclopentane, cyclohexane, or
mixtures thereof; mono-olefins such as, for example, 1-butene,
2-butene, or mixtures thereof; aromatic hydrocarbons such as, for
example, benzene, toluene, xylene, or mixtures thereof; halogenated
hydrocarbons such as, for example, methylene chloride, chloroform,
carbon tetrachloride, trichloroethylene, perchloroethylene,
1,2-dichloroethane, chlorobenzene, bromobenzene, chlorotoluene, or
mixtures thereof. The (co)polymerization solvent is preferably
selected from saturated aliphatic hydrocarbons.
[0077] Alternatively, said (co)polymerization can be carried out
using, as (co)polymerization solvent, the same conjugated diene(s)
to be (co)polymerized, according to the process known as "bulk
process".
[0078] The concentration of conjugated diene to be (co)polymerized
in said (co)polymerization solvent generally ranges from 5% by
weight to 50% by weight, preferably from 10% by weight to 20% by
weight, with respect to the total weight of the conjugated
diene/solvent mixture.
[0079] Generally, said (co)polymerization can be carried out at a
temperature ranging from -70.degree. C. to +100.degree. C.,
preferably from -20.degree. C. to +80.degree. C.
[0080] As far as the pressure is concerned, it is preferable to
operate at the pressure of the components of the mixture to be
(co)polymerized.
[0081] Said (co)polymerization can be carried out either in
continuous or batchwise.
[0082] As indicated above, the use of the bis-imine pyridine
complex of lanthanides having general formula (I) allows
(co)polymers of conjugated dienes to be obtained, in particular
linear or branched polybutadiene and polyisoprene, with a high
content of 1,4-cis units, i.e. a content of 1,4-cis units 99% in
the case of polybutadiene, and 98% in the case of polyisoprene.
Some illustrative and non-limiting examples are provided hereunder
for a better understanding of the present invention and for its
practical embodiment.
EXAMPLES
Reagents and Materials
[0083] The reagents and materials used in the following examples of
the invention are indicated in the following list, together with
their optional pretreatment and their supplier: [0084] aniline
(Aldrich): distilled before use; [0085] neodymium
trichloride/tetrahydrofuran complex [NdCl.sub.3 (2THF)]: obtained
by the extraction of neodymium trichloride (NdCl.sub.3) (Strem
Chemicals) with tetrahydrofuran (THF) at boiling point, as
described by Yang J. H. et al., in "Macromolecules" (1982), Vol.
15(2), pages 230-233; [0086] tetrahydrofuran (THF) (Carlo Erba,
RPE): kept at reflux temperature on potassium/benzophenone and then
distilled under nitrogen; [0087] methanol (Carlo Erba, RPE): used
as such; [0088] ethanol (Carlo Erba, RPE): used as such; [0089]
isopropyl alcohol (Carlo Erba, RPE): used as such; [0090] formic
acid (85%) (Carlo Erba, RPE): used as such; [0091] o-toluidine
(Aldrich): used as such; [0092] 2-tert-butylaniline (Aldrich): used
as such; [0093] 2,4,6-trimethylaniline (Aldrich): used as such;
[0094] 2,6-di-isopropylaniline (Aldrich): used as such; [0095]
cyclohexylamine (Aldrich): used as such; [0096] benzylamine
(Aldrich): used as such; [0097] 2,6-diacetylpyridine (Aldrich):
used as such; [0098] glacial acetic acid (Aldrich): used as such;
[0099] toluene (Aldrich): pure, .gtoreq.99.5%, distilled on sodium
(Na) in an inert atmosphere; [0100] 1,3-butadiene (Air Liquide):
pure, .gtoreq.99.5%, evaporated from the container before each
production, dried by passing it through a column packed with
molecular sieves and condensed inside the reactor pre-cooled to
-20.degree. C.; [0101] isoprene (Aldrich): pure, .gtoreq.99%,
refluxed on calcium hydride, then distilled "trap-to-trap" and kept
in a nitrogen atmosphere; [0102] tetra-iso-butyl-aluminoxane
(TIBAO) (Akzo Nobel): cyclohexane solution at 10% by weight; [0103]
methylaluminoxane (MAO) (Aldrich): toluene solution at 10% by
weight; [0104] di-iso-butyl-aluminium hydride (DIBAH) (Aldrich):
used as such; [0105] Nd-2-ethylhexanoate
[Nd(OCOC.sub.17H.sub.15).sub.3] (Aldrich): 0.05 M solution in
heptane; [0106] heptane (Aldrich): pure, .gtoreq.99%, distilled on
sodium (Na) in an inert atmosphere; [0107] pentane (Aldrich): pure,
.gtoreq.99%, distilled on sodium (Na) in an inert atmosphere;
[0108] di-ethyl aluminium chloride [AlEt.sub.2Cl] (Akzo Nobel):
used as such; [0109] tri-iso-butyl aluminium [TIBA] (Akzo Nobel):
used as such; [0110] deuterated tetrachloroethylene
(C.sub.2D.sub.2Cl.sub.4) (Acros): used as such; [0111] deuterated
chloroform deuterato (CDCl.sub.3) (Acros): used as such.
[0112] The analysis and characterization methods indicated below
were used.
[0113] Elemental Analysis
[0114] a) Determination of Nd
[0115] For the determination of the weight quantity of the metal Nd
in the bis-imine pyridine complexes of lanthanides object of the
present invention, an aliquot weighed exactly, operating in a
dry-box under a nitrogen flow, of about 30-50 mg of sample, was
placed in a platinum crucible of about 30 ml, together with a
mixture of 1 ml of hydrofluoric acid (HF) at 40%, 0.25 ml of
sulfuric (H.sub.2SO.sub.4) at 96% and 1 ml of nitric acid
(HNO.sub.3) at 70%. The crucible was then heated on a plate,
increasing the temperature until the appearance of white sulfuric
fumes (about 200.degree. C.). The mixture thus obtained was cooled
to room temperature (20.degree. C.-25.degree. C.), 1 ml of nitric
acid (HNO.sub.3) at 70% was added and the mixture was then heated
until the appearance of fumes. After repeating the sequence a
further two times, a limpid, almost colourless solution was
obtained. 1 ml of nitric acid (HNO.sub.3) and about 15 ml of water
were then added, without heat, and the mixture was then heated to
80.degree. C. for about 30 minutes. The sample thus prepared was
diluted with water, having a MilliQ purity, up to a weight of about
50 g, weighed exactly, to obtain a solution on which analytical
instrumental determination was carried out using an ICP-OES
(optical detection plasma) Thermo Optek IRIS Advantage Duo
spectrometer, by comparison with solutions at a known
concentration. For this aim, a calibration curve was prepared for
each analyte, within the range of 0 ppm-10 ppm, measuring solutions
having a known titre obtained by weight dilution of certified
solutions.
[0116] The solution of the sample prepared as described above was
diluted again by weight so as to obtain concentrations close to
those used as reference, before carrying out spectrophotometric
detection. All the samples were prepared in duplicate. The results
were considered acceptable if the single data of the tests in
duplicate did not differ by more than 2% relative with respect to
their average value.
[0117] b) Chlorine Determination
[0118] For this aim, samples of the bis-imine pyridine complexes of
lanthanides object of the present invention, about 30 mg-50 mg,
were weighed exactly in 100 ml glasses in a dry-box under a stream
of nitrogen. 2 g of sodium carbonate (Na.sub.2CO.sub.3) and,
outside the dry-box, ml of MillQ water, were added. The mixture was
brought to boiling point, on a plate under magnetic stirring, for
about 30 minutes. It was left to cool, sulfuric acid
(H.sub.2SO.sub.4) diluted 1/5, was added until the reaction became
acid and the mixture was titrated with silver nitrate (AgNO.sub.3)
0.1N with a potentiometer titrimeter.
[0119] c) Determination of Carbon, Hydrogen and Nitrogen
[0120] The determination of the carbon, hydrogen and nitrogen, in
the bis-imine pyridine complexes of lanthanides object of the
present invention, and also in the ligands used for the aim of the
present invention, was carried out by means of an automatic
analyzer Carlo Erba Mod. 1106.
[0121] .sup.13C-HMR and .sup.1H-HMR Spectra
[0122] The .sup.13C-HMR and .sup.1H-HMR spectra were registered by
means of a nuclear magnetic resonance spectrometer mod. Bruker
Avance 400, using deuterated tetrachloroethylene
(C.sub.2D.sub.2Cl.sub.4) at 103.degree. C., and
hexamethyldisiloxane (HDMS) as internal standard, or using
deuterated chloroform (CDCl.sub.3), at 25.degree. C., and
tetramethylsilane (TMS) as internal standard. Solutions of the
ligands used in the present invention or polymeric solutions having
concentrations equal to 10% by weight with respect to the total
weight of the solution of ligands used in the present invention or
polymeric solution, respectively, were used for the aim.
[0123] The microstructure of the polymers [i.e. content of 1,4-cis
units (%)] was determined by analysis of the above spectra on the
basis of what is indicated in literature by Mochel, V. D., in
"Journal of Polymer Science Part A-1: Polymer Chemistry" (1972),
Vol. 10, Issue 4, pages 1009-1018, for polybutadiene; and by Sato,
H., et al., in "Journal of Polymer Science: Polymer Chemistry
Edition" (1979), Vol. 17, Issue 11, pages 3551-3558 for
polyisoprene.
[0124] I.R. Spectra
[0125] The I.R. spectra (FT-IR) were registered by means of a
Bruker IFS 48 spectrophotometer.
[0126] The I.R. spectra (FT-IR) of the ligands used in the present
invention were obtained by dispersing the ligand to be analyzed in
anhydrous potassium bromide (KBr) (disks of KBr), or in a
suspension of nujol.
[0127] The I.R. spectra (FT-IR) of the bis-imine pyridine complexes
of lanthanides object of the present invention, were obtained by
dispersing the bis-imine pyridine complex of lanthanides to be
analyzed in anhydrous potassium bromide (KBr) (disks of KBr), or in
a suspension of nujol.
[0128] The I.R. spectra (FT-IR) of the polymers were obtamed from
polymeric films on tablets of potassium bromide (KBr), said films
being obtained by deposition of a solution of the polymer to be
analyzed in hot odichlorobenzene. The concentration of the
polymeric solutions analyzed was equal to 10% by weight with
respect to the total weight of the polymeric solution.
[0129] Thermal Analysis (DSC)
[0130] The DSC ("Differential Scanning calorimetry") thermal
analysis, for determining the melting point (T.sub.m) and the
crystallization temperature (T.sub.c) of the polymers obtamed, was
carried out using a Perkin Elmer Pyris differential scanning
calorimeter. For this aim, 5 mg of polymer were analyzed, with a
scanning rate ranging from 1.degree. C./min to 20.degree. C./min,
in an inert nitrogen atmosphere.
[0131] The DSC ("Differential Scanning calorimetry") thermal
analysis, for determining the glass transition temperature (TO of
the polymers obtained and of the natural rubber (NR), was carried
out by means of the above calorimeter, using the following thermal
program: isotherm for 3 minutes at +70.degree. C.; cooling from
+70.degree. C. to -90.degree. C. at a rate of 10.degree. C./min;
isotherm for 3 min at -90.degree. C.; heating from -90.degree. C.
to +70.degree. C. at a rate of 10.degree. C./min.
[0132] Molecular Weight Determination
[0133] The determination of the molecular weight (MW) of the
polymers obtained was carried out by means of GPC ("Gel Permeation
Chromatography") operating under the following conditions: [0134]
Agilent 1100 pump; [0135] I.R. Agilent 1100 detector; [0136] PL
Mixed-A columns; [0137] solvent/eluent: tetrahydrofuran (THF);
[0138] flow-rate: 1 ml/min; [0139] temperature: 25.degree. C.;
[0140] molecular mass calculation: Universal Calibration
method.
[0141] The weight average molecular weight (M.sub.w) and the
polydispersity Index (PDI) corresponding to the M.sub.w/M.sub.n
ratio (M.sub.n=number average molecular weight), are specified.
[0142] Determination of the Branching
[0143] The determination of the branching of the polymers obtained
was carried out by means of the GPC/MALLS technique obtained by
coupling a multi-angle light scattering detector (MALLS) with a
traditional SEC/RI elution system, operating under the following
conditions:
[0144] Agilent 1050 pump;
[0145] I.R. Agilent 1050 detector;
[0146] MALLS Dawn-DSP Wyatt detector--Technology, .lamda.=632.8
nm;
[0147] PL GEL Mixed-A (.times.4) columns;
[0148] solvent/eluent: tetrahydrofuran (THF);
[0149] flow-rate: 1 ml/min;
[0150] temperature: 25.degree. C.
[0151] Operating as described above, the absolute measurement can
be contemporaneously carried out of the molecular weight and of the
gyration radius of the macromolecules that are separated by the
chromatographic system: the quantity of light scattered from a
macromolecular species in solution can in fact be used directly for
obtaining its molecular weight, whereas the angular variation in
the scattering is directly correlated to its average dimensions.
The fundamental relation which is used is represented by the
following equation (1):
K * c R .theta. = 1 M w P .theta. + 2 A 2 c ( 1 ) ##EQU00001##
wherein: K* is the optical constant which depends on the wavelength
of the light used, the refraction index (dn/dc) of the polymer, the
solvent used; M.sub.w is the weight average molecular weight; c is
the concentration of the polymeric solution; R.sub..theta. is the
intensity of the light scattered, measured at the angle .theta.
(excess Rayleigh factor);
[0152] P.sub..theta. is the function describing the variation of
the light scattered with the angle at which it is measured, for an
angle .theta. equal to 0;
[0153] A.sub.2 is the second virial coefficient.
[0154] For very low concentrations (typical of a GPC system), the
equation (1) indicated above is reduced to the following equation
(2):
K * c R .theta. = 1 M w P .theta. ( 2 ) ##EQU00002##
wherein K*, c, R.sub..theta., M.sub.w and P.sub..theta., have the
same meanings defined above, and by carrying out the measurement on
several angles, the extrapolation to angle null of the function
K*c/R.sub..theta. in relation to sen.sup.2.theta./2 directly
provides the molecular weight from the intercept value and the
gyration radius of the slope.
[0155] Furthermore, as this measurement is carried out for every
slice of the chromatogram, it is possible to obtain a distribution
of both the molecular weight and the gyration radius.
[0156] The macromolecular dimensions in solution are directly
correlated to their branching degree: for the same molecular
weight, the smaller the dimensions of the macromolecule with
respect to the linear correspondent, the higher the branching
degree will be.
[0157] Informations relating to the macrostructure of the polymer
is qualitatively deduced from the value of the parameter .alpha.,
which represents the slope of the curve which correlates the
gyration radius with the molecular weight: when, under the same
analysis conditions, this value decreases with respect to a
macrostructure of the linear type, there is the presence of a
polymer having a branched-type macrostructure. The typical value of
the parameter .alpha., for linear polybutadiene having a high
content of 1,4-cis units, in tetrahydrofuran (THF), is equal to
0.58-0.60.
Example 1
Synthesis of the Ligand Having Formula (L1)
##STR00005##
[0159] 2.10 ml (0.023 moles) of aniline were introduced into a
reaction flask together with 5 ml of methanol and 5 drops of formic
acid, obtaining a solution. 20 ml of methanol containing 1.79 g
(0.011 moles) of diacetylpyridine, were subsequently added,
dropwise, at room temperature, to said solution. The solution was
left under stirring the whole night obtaining the precipitation of
a yellow microcrystalline solid: said yellow solid was recovered by
filtration, washed with cold methanol and dried, under vacuum, at
room temperature, obtaining 2.76 g of a yellow solid (yield=80%)
having formula (L1).
[0160] Elemental analysis [found (calculated)]: C, 80.9% (80.5%);
H, 6.13% (6.11%); N, 13.6% (13.4%).
[0161] Molecular weight (MW): 313.4.
[0162] FT-IR (nujol): 1632 cm.sup.-1 .nu..sub.(C.dbd.N).
[0163] .sup.1H-NMR (CDCl.sub.3): 2.4 (s, 6H), 6.84 (d, 4H), 7.11
(t, 2H), 7.36 (t, 4H), 7.88 (t, 1H), 8.36 (d, 2H).
Example 2
Synthesis of the Ligand Having Formula (L2)
##STR00006##
[0165] 2.44 ml (0.023) of o-toluidine were introduced into a
reaction flask together with 5 ml of methanol and 5 drops of formic
acid, obtaining a solution. 20 ml of methanol containing 1.79 g
(0.011 moles) of 2,6-diacetylpyridine were subsequently added,
dropwise, at room temperature, to said solution. The solution was
left under stirring the whole night obtaining the precipitation of
a yellow microcrystalline solid: said yellow solid was recovered by
filtration, washed with cold methanol and dried, under vacuum, at
room temperature, obtaining 1.52 g of a yellow solid (yield=40%)
having formula (L2).
[0166] Elemental analysis [found (calculated)]: C, 81.2% (80.9%);
H, 6.83% (6.76%); N, 12.2% (12.3%).
[0167] Molecular weight (MW): 341.46.
[0168] FT-IR (nujol): 1641 cm.sup.-1 .nu..sub.(C.dbd.N).
[0169] .sup.1H-NMR (CDCl.sub.3): 2.4 (s, 6H), 6.84 (d, 4H), 7.11
(t, 2H), 7.28 (t, 4H), 7.91 (t, 1H), 8.49 (d, 2H).
Example 3
Synthesis of the Ligand Having Formula (L3)
##STR00007##
[0171] A solution of 2,6-diisopropylaniline (3.47 ml; 0.0184 moles)
in methanol (10 ml) was added, dropwise, to a solution of
2,6-diacetylpyridine (1.5 g; 0.0092 moles) in methanol (25 ml) and
5 drops of formic acid were subsequently added, obtaining a
solution. Said solution was subsequently heated to reflux
temperature, for 48 hours. At the end, the solution was
concentrated to half of its volume and cooled in a freezer,
obtaining the precipitation of a yellow microcrystalline solid:
said yellow solid was recovered by filtration, washed with cold
methanol and dried, under vacuum, at room temperature, obtaining
3.5 g of a yellow solid (yield=80%) having formula (L3).
[0172] Elemental analysis [found (calculated)]: C, 81.9% (82.28%);
H, 8.5% (9%); N, 8.72% (8.72%).
[0173] Molecular weight (MW): 481.72.
[0174] FT-IR (nujol): 1646 cm.sup.-1 .nu..sub.(C.dbd.N).
[0175] .sup.1H-NMR (CDCl.sub.3): 1.15 (d, 24H), 2.24 (s, 6H), 2.81
(m, 4H), 7.15 (m, 6H), 7.9-8.5 (m, 3H).
Example 4
Synthesis of the Ligand Having Formula (L4)
##STR00008##
[0177] 1.944 g (0.0196 moles) of cyclohexylamine were poured into a
reaction flask together with 10 ml of ethanol and 3 drops of formic
acid, obtaining a solution. 20 ml of ethanol containing 1.6 g
(0.0098 moles) of 2,6-diacetylpyridine, were subsequently added,
dropwise, at room temperature, to said solution, The solution was
left under stirring the whole night obtaining the precipitation of
a whitish microcrystalline solid: said whitish solid was recovered
by filtration, washed with cold methanol and dried, under vacuum,
at room temperature, obtaining 1.5 g of a whitish solid (yield=47%)
having formula (L4).
[0178] Elemental analysis [found (calculated)]: C, 76.68% (77.49%);
H, 9.42% (9.60%); N, 12.49% (12.91%).
[0179] Molecular weight (MW): 325.50.
[0180] FT-IR (nujol): 1635 cm.sup.-1 .nu..sub.(C.dbd.N).
[0181] .sup.1H-NMR (CDCl.sub.3): 2.4 (s, 6H), 6.84 (d, 4H), 7.11
(t, 2H), 7.28 (t, 4H), 7.91 (t, 1H), 8.49 (d, 2H).
Example 5
Synthesis of the Ligand Having Formula (L5)
##STR00009##
[0183] 2.13 ml (0.012 moles) of 2,6-diisopropylaniline were
introduced into a reaction flask together with 5 ml of methanol and
3 drops of formic acid, obtaining a solution. 20 ml of methanol
containing 1.93 g (0.012 moles) of 2,6-diacetylpyridine were
subsequently added dropwise, at room temperature, to said solution,
obtaining the precipitation of a yellow microcrystalline solid:
after 1 hour, said yellow solid was recovered by filtration, washed
with cold methanol and dried, under vacuum, at room temperature,
obtaining 2.53 g of a light-yellow solid (yield=65%) having formula
(L5a):
##STR00010##
[0184] Elemental analysis [found (calculated)]: C, 77.8% (78.2%);
H, 8.29% (8.13%); N, 8.51% (8.69%).
[0185] Molecular weight (MW): 322.45.
[0186] FT-IR (nujol): 1699 cm.sup.-1 .nu..sub.(C.dbd.O), 1645
cm.sup.-1 .nu..sub.(C.dbd.N)
[0187] .sup.1H-NMR (CDCl.sub.3): 1.16 (d, 6H), 1.17 (d, 6H), 2.28
(s, 3H), 2.74 (m, 2H), 2.81 (s, 3H), 7.08-7.22 (m, 3H), 7.95 (t,
1H), 8.16 (dd, 1H), 8.58 (dd, 1H).
[0188] 2.0 g (6.2.times.10.sup.-3 moles) of the compound having
formula (L5a) obtained as described above, were dissolved in 100 ml
of warm isopropyl alcohol and, subsequently, 5 drops of formic acid
and, dropwise, 0.62 g (6.82.times.10.sup.-3 moles) of freshly
distilled aniline, were added: the whole mixture was left at
reflux, for 8 hours, obtaining 1.5 g of a yellow solid (yield=61%)
having formula (L5).
[0189] Elemental analysis [found (calculated)]: C, 81.10% (81.57%);
H, 7.93% (7.86%); N, 10.40% (10.57%).
[0190] Molecular weight (MW): 397.56.
[0191] FT-IR (nujol): 1637 cm.sup.-1 .nu..sub.(C.dbd.O), 1639
cm.sup.-1 .nu..sub.(C.dbd.N).
[0192] FIG. 11 shows the FT-IR (nujol) spectrum of the ligand
having formula (L5) obtained.
Example 6
Synthesis of the Ligand Having Formula (L6)
##STR00011##
[0194] 5.37 g (0.036 moles) of 2-tert-butylaniline were introduced
into a reaction flask together with 15 ml of methanol and 5 drops
of formic acid, obtaining a solution. 30 ml of methanol containing
5.87 g (0.036 moles) of 2,6-diacetylpyridine were subsequently
added dropwise, at room temperature, to said solution, obtaining
the precipitation of a yellow microcrystalline solid: after 1 hour,
said yellow solid was recovered by filtration, washed with cold
methanol and dried, under vacuum, at room temperature, obtaining
9.84 g of a light-yellow solid (yield=93%) having formula
(L6a):
##STR00012##
[0195] Elemental analysis [found (calculated)]: C, 78.0% (77.5%);
H, 7.60% (7.53%); N, 9.65% (9.52%).
[0196] Molecular weight (MW): 294.4.
[0197] FT-IR (nujol): 1694 cm.sup.-1 .nu..sub.(C.dbd.O), 1644
cm.sup.-1 .nu..sub.(C.dbd.N)
[0198] .sup.1H-NMR (CDCl.sub.3): 1.39 (s, 9H), 2.41 (s, 3H), 2.80
(s, 3H), 2.54 (dd, 1H), 7.24 (m, 2H), 7.43 (dd, 1H), 7.95 (t, 1H),
8.13 (dd, 1H), 8.50 (dd, 1H).
[0199] 6.90 g (2.35.times.10.sup.-2 moles) of the compound having
formula (L6a) obtained as described above, were refluxed in 100 ml
of absolute ethanol, and 2.19 g (2.35.times.10.sup.-2 moles) of
freshly distilled aniline were then added dropwise: the whole
mixture was left at reflux, for 8 hours, obtaining 6.3 g of a
yellow solid (yield=73%) having formula (L6).
[0200] Elemental analysis [found (calculated)]: C, 81.20% (81.26%);
H, 7.30% (7.37%); N, 11.47% (11.37%).
[0201] Molecular weight (MW): 369.50.
[0202] FT-IR (nujol): 1636 cm.sup.-1 .nu..sub.(C.dbd.N).
Example 7
Synthesis of the Ligand (L7)
##STR00013##
[0204] 2.0 g (6.2.times.10.sup.-3 moles) of the compound (L5a)
obtained as described above, were introduced into a reaction flask
with 100 ml of absolute ethanol, and 0.75 g (6.82.times.10.sup.-3
moles) of benzylamine and 5 drops of glacial acetic acid were then
added, under stirring: the whole mixture was left, under stirring,
at room temperature, for 24 hours, obtaining 5.74 g of a
light-yellow solid (yield=65%) having formula (L7).
[0205] Elemental analysis [found (calculated)]: C, 81.2% (81.71%);
H, 8.1% (8.08%); N, 9.7% (10.21%).
[0206] Molecular weight (MW): 411.59.
[0207] FT-IR (nujol): 1634 cm.sup.-1 .nu..sub.(C.dbd.N).
Example 8
Synthesis of the Ligand Having Formula (L8)
##STR00014##
[0209] 6.90 g (2.35.times.10.sup.-2 moles) of the compound (L6a)
obtained as described above, were refluxed in 100 ml of absolute
ethanol, and 2.30 g (2.35.times.10.sup.-2 moles) of cyclohexylamine
were then added dropwise: the whole mixture was left at reflux
temperature, for 8 hours, obtaining 5.74 g of a yellow solid
(yield=65%) having formula (L8).
[0210] Elemental analysis [found (calculated)]: C, 80.05% (79.95%);
H, 8.90% (8.86%); N, 11.20% (11.19%).
[0211] Molecular weight (MW): 375.55.
[0212] FT-IR (nujol): 1637 cm.sup.-1 .nu..sub.(C.dbd.N).
Example 9
Synthesis of NdCl.sub.3(L1) [Sample GL380/P1891]
##STR00015##
[0214] The complex neodymium trichloride/tetrahydrofuran
[NdCl.sub.3(2THF)] (0.641 g; 1.6.times.10.sup.-3 moles) was
introduced into a 100 ml reaction flask together with
tetrahydrofuran (THF) (50 ml). The whole mixture was kept under
stirring, at room temperature, for a few minutes, and the ligand
having formula (L1) (0.564 g; 1.8.times.10.sup.-3 moles; molar
ratio L1/Nd=1.13), obtained as described in Example 1, was then
added. The whole mixture was kept under stirring, at room
temperature, for 72 hours, obtaining an extremely dense white/green
suspension. At the end of the reaction, the solvent was almost
completely removed by volume under vacuum, pentane in excess was
added and the whole mixture was subsequently filtered obtaining a
white/green solid residue which was washed various times with
pentane, in order to remove the non-reacted ligand. The white/green
residue remaining on the filter was recovered and dried under
vacuum obtaining 0.780 g of a solid product corresponding to the
complex NdCl.sub.3(L1), equal to a conversion of 86.4% with respect
to the neodymium charged.
[0215] Elemental analysis [found (calculated)]: C, 44.60% (44.72%);
H, 3.30% (3.40%); N, 7.30% (7.45%); Cl, 19.0% (18.86%); Nd, 25.60%
(25.57%).
[0216] Molecular weight (MW): 564.0.
[0217] FT-IR (nujol): 1645 cm.sup.-1 .nu..sub.(C.dbd.N).
Example 10
Synthesis of NdCl.sub.3(L2) [Sample GL360]
##STR00016##
[0219] The complex neodymium trichloride/tetrahydrofuran
[NdCl.sub.3(2THF)] (0.305 g; 7.72.times.10.sup.-4 moles) was
introduced into a 100 ml reaction flask together with
tetrahydrofuran (THF) (35 ml). The whole mixture was kept under
stirring, at room temperature, for a few minutes, and the ligand
having formula (L2) (0.313 g; 9.times.10.sup.-4 moles; molar ratio
L2/Nd=1.2), obtained as described in Example 2, was then added. The
whole mixture was kept under stirring, at room temperature, for 2
days: at the beginning a green/yellow suspension was formed which
subsequently became red-coloured as the reaction proceeded. At the
end of the reaction, the solvent was considerably reduced in volume
under vacuum, pentane in excess was added and the whole mixture was
subsequently filtered obtaining a red solid residue which was
washed various times with pentane, in order to remove the
non-reacted ligand. The red-coloured residue remaining on the
filter was recovered and dried under vacuum obtaining 0.425 g of a
solid product corresponding to the complex NdCl.sub.3(L2), equal to
a conversion of 93% with respect to the neodymium charged.
[0220] Elemental analysis [found (calculated)]: C, 46.50% (46.66%);
H, 3.80% (3.92%); N, 6.90% (7.10%); Cl, 18.10% (17.96%); Nd, 24.50%
(24.36%).
[0221] Molecular weight (MW): 592.05.
[0222] FT-IR (nujol): 1648 cm.sup.-1 .nu..sub.(C.dbd.N).
Example 11
Synthesis of NdCl.sub.3(L4) [Sample P1888]
##STR00017##
[0224] The complex neodymium trichloride/tetrahydrofuran
[NdCl.sub.3(2THF)] ((0.7 g; 1.8.times.10.sup.-3 moles) was
introduced into a 100 ml reaction flask together with
tetrahydrofuran (THF) (50 ml). The whole mixture was kept under
stirring, at room temperature, for a few minutes, and the ligand
having formula (L4) (0.762 g; 2.3.times.10.sup.-3 moles; molar
ratio L4/Nd=1.3), obtained as described in Example 3, was then
added. The whole mixture was kept under stirring, at room
temperature, for 3 days: at the beginning a yellowish suspension
was formed which subsequently became yellow/red-coloured as the
reaction proceeded. At the end of the reaction, the solvent was
considerably reduced in volume under vacuum, pentane in excess was
added and the whole mixture was subsequently filtered obtaining a
yellowish solid residue which was washed various times with
pentane, in order to remove the non-reacted ligand. The yellowish
residue remaining on the filter was recovered and dried under
vacuum obtaining 0.860 g of a solid product corresponding to the
complex NdCl.sub.3(L4), equal to a conversion of 82.9% with respect
to the neodymium charged.
[0225] Elemental analysis [found (calculated)]: C, 43.60% (43.78%);
H, 5.30% (5.42%); N, 7.20% (7.29%); Cl, 18.5% (18.46); Nd, 25.10%
(25.04%).
[0226] Molecular weight (MW): 576.0.
[0227] FT-IR (nujol): 1589 cm.sup.-1 .nu..sub.(C.dbd.N).
Example 12
Synthesis of NdCl.sub.3(L5) [Sample P1963]
##STR00018##
[0229] The complex neodymium trichloride/tetrahydrofuran
[NdCl.sub.3(2THF)] (0.557 g; 1.4.times.10.sup.-3 moles) was
introduced into a 100 ml reaction flask together with
tetrahydrofuran (THF) (50 ml). The whole mixture was kept under
stirring, at room temperature, for a few minutes, and the ligand
having formula (L5) (0.729 g; 1.83.times.10.sup.-3 moles; molar
ratio L5/Nd=1.3), obtained as described in Example 5, was then
added. The whole mixture was kept under vigorous stirring, at room
temperature, for days obtaining a relatively homogeneous
greencoloured solution. At the end of the reaction, the solvent was
partially removed under vacuum, pentane in excess was added and the
whole mixture was subsequently filtered obtaining a greenish solid
residue which was washed various times with pentane, in order to
remove the non-reacted ligand. The greenish residue remaining on
the filter was recovered and dried under vacuum obtaining 0.798 g
of a solid product corresponding to the complex NdCl.sub.3(L5),
equal to a conversion of 87.9% with respect to the neodymium
charged.
[0230] Elemental analysis [found (calculated)]: C, 50.10% (50.03%);
H, 4.90% (4.82%); N, 6.60% (6.48%); Cl, 16.5% (16.41); Nd, 22.30%
(22.25%).
[0231] Molecular weight (MW): 648.16.
[0232] FT-IR (nujol): 1643 cm.sup.-1 (.nu..sub.C.dbd.N--Nd); 1605
cm.sup.-1 (.nu..sub.(Py)NNd).
[0233] FIG. 12 shows the FT-IR spectrum of the complex
NdCl.sub.3(L5).
Example 13
Synthesis of NdCl.sub.3(L6) [Sample P1965]
##STR00019##
[0235] The complex neodymium trichloride/tetrahydrofuran
[NdCl.sub.3(2THF)] (0.497 g; 1.26.times.10.sup.-3 moles) was
introduced into a 100 ml reaction flask together with
tetrahydrofuran (THF) (40 ml). The whole mixture was kept under
stirring, at room temperature, for a few minutes, and the ligand
having formula (L6) (0.605 g; 1.64.times.10.sup.-3 moles; molar
ratio L6/Nd=1.3), obtained as described in Example 6, was then
added. The whole mixture was kept under stirring, at room
temperature, for 4 days obtaining a relatively homogeneous greenish
solution. At the end of the reaction, the solvent was partially
removed under vacuum, pentane in excess was added and the whole
mixture was subsequently filtered obtaining a greenish solid
residue which was washed various times with pentane, in order to
remove the non-reacted ligand. The greenish residue remaining on
the filter was recovered and dried under vacuum obtaining 0.692 g
of a solid product corresponding to the complex NdCl.sub.3(L6),
equal to a conversion of 88.5% with respect to the neodymium
charged.
[0236] Elemental analysis [found (calculated)]: C, 48.20% (48.42%);
H, 4.30% (4.39%); N, 6.60% (6.78%); Cl, 17.2% (17.15%); Nd, 23.30%
(23.26%).
[0237] Molecular weight (MW): 620.10.
[0238] FT-IR (nujol): 1645 cm.sup.-1 (.nu..sub.C.dbd.N--Nd); 1605
cm.sup.-1 (.nu..sub.(Py)NNd).
Example 14
Synthesis of NdCl.sub.3(L8) [Sample P1964]
##STR00020##
[0240] The complex neodymium trichloride/tetrahydrofuran
[NdCl.sub.3(2THF)] (0.522 g; 1.32.times.10.sup.-3 moles) was
introduced into a 100 ml reaction flask together with
tetrahydrofuran (THF) (40 ml). The whole mixture was kept under
stirring, at room temperature, for a few minutes, and the ligand
having formula (L8) (0.645 g; 1.72.times.10.sup.-3 moles; molar
ratio L8/Nd=1.3), obtained as described in Example 8, was then
added. The whole mixture was kept under stirring, at room
temperature, for 4 days obtaining a relatively homogeneous greenish
solution. At the end of the reaction, the solvent was partially
removed under vacuum, pentane in excess was added and the whole
mixture was subsequently filtered obtaining a greenish solid
residue which was washed various times with pentane, in order to
remove the non-reacted ligand. The greenish residue remaining on
the filter was recovered and dried under vacuum obtaining 0.645 g
of a solid product corresponding to the complex NdCl.sub.3(L8),
equal to a conversion of 78% with respect to the neodymium
charged.
[0241] Elemental analysis [found (calculated)]: C, 48.10% (47.96%);
H, 5.40% (5.31%); N, 6.90% (6.71%); Cl, 19.5% (19.59%); Nd, 26.50%
(26.56%).
[0242] Molecular weight (MW): 626.15.
[0243] FT-IR (nujol): 1643 cm.sup.-1 (.nu..sub.C.dbd.N--Nd); 1604
cm.sup.-1 (.nu..sub.(Py)NNd).
Example 15
P1920
[0244] 2 ml of 1,3-butadiene, equal to about 1.4 g, were condensed,
at a low temperature (-20.degree. C.), in a 25 ml test-tube. 7 ml
of heptane were then added and the temperature of the solution thus
obtained was brought to 20.degree. C. Tetra-iso-butyl-aluminoxane
(TIBAO) in a cyclohexane solution (6.2 ml; 1.times.10.sup.-2 moles,
equal to about 2.9 g) was then added, and subsequently the complex
NdCl.sub.3(L1) [sample GL380/P1891] (2.8 ml of a toluene solution
at a concentration equal to 2 mg/ml; 1.times.10.sup.-5 moles, equal
to about 5.6 mg) obtained as described in Example 9. The whole
mixture was kept, under magnetic stirring, at 20.degree. C., for 3
hours. The polymerization was then quenched by the addition of 2 ml
of methanol containing a few drops of hydrochloric acid. The
polymer obtained was subsequently coagulated by the addition of 40
ml of a methanol solution containing 4% of antioxidant Irganox.RTM.
1076 (Ciba) obtaining 0.603 g of polybutadiene having a content of
1,4-cis units >99%: further characteristics of the process and
of the polybutadiene obtained are indicated in Table 1.
Example 16
P1941
[0245] 2 ml of 1,3-butadiene, equal to about 1.4 g, were condensed,
at a low temperature (-20.degree. C.), in a 25 ml test-tube. 6.9 ml
of toluene were then added and the temperature of the solution thus
obtained was brought to 20.degree. C. Methylaluminoxane (MAO) in a
toluene solution (6.3 ml; 1.times.10.sup.-2 moles, equal to about
0.58 g) was then added, and subsequently the complex NdCl.sub.3(L1)
[sample GL380/P1891] (2.8 ml of a toluene solution at a
concentration equal to 2 mg/ml; 1.times.10.sup.-5 moles, equal to
about 5.6 mg) obtained as described in Example 9. The whole mixture
was kept, under magnetic stirring, at 20.degree. C., for 116 hours.
The polymerization was then quenched by the addition of 2 ml of
methanol containing a few drops of hydrochloric acid. The polymer
obtained was subsequently coagulated by the addition of 40 ml of a
methanol solution containing 4% of antioxidant Irganox.RTM. 1076
(Ciba) obtaining 0.755 g of polybutadiene having a content of
1,4-cis units >99%: further characteristics of the process and
of the polybutadiene obtained are indicated in Table 1.
Example 17
A007
[0246] 2 ml of 1,3-butadiene, equal to about 1.4 g, were condensed,
at a low temperature (-20.degree. C.), in a 25 ml test-tube. 13.02
ml of heptane were then added and the temperature of the solution
thus obtained was brought to 20.degree. C. Di-iso-butyl-aluminium
hydride (DIBAH) (0.18 ml; 1 mmole, equal to about 144 mg) was then
added, and subsequently the complex NdCl.sub.3(L1) [sample
GL380/P1891] (2.8 ml of a toluene solution at a concentration equal
to 2 mg/ml; 1.times.10.sup.-5 moles, equal to about 5.6 mg)
obtained as described in Example 9. The whole mixture was kept,
under magnetic stirring, at 20.degree. C., for 8 hours. The
polymerization was then quenched by the addition of 2 ml of
methanol containing a few drops of hydrochloric acid. The polymer
obtained was subsequently coagulated by the addition of 40 ml of a
methanol solution containing 4% of antioxidant Irganox.RTM. 1076
(Ciba) obtaining 0.443 g of polybutadiene having a content of
1,4-cis units >99%: further characteristics of the process and
of the polybutadiene obtained are indicated in Table 1.
Example 18
GL503
[0247] 2 ml of 1,3-butadiene, equal to about 1.4 g, were condensed,
at a low temperature (-20.degree. C.), in a 25 ml test-tube. 6.85
ml of heptane were then added and the temperature of the solution
thus obtained was brought to 20.degree. C.
Tetra-iso-butyl-aluminoxane (TIBAO) in a cyclohexane solution (6.2
ml; 1.times.10.sup.-2 moles, equal to about 2.9 g) was then added,
and subsequently the complex NdCl.sub.3(L2) [sample GL360] (2.8 ml
of a toluene solution at a concentration equal to 2 mg/ml;
1.times.10.sup.-5 moles, equal to about 5.9 mg) obtained as
described in Example 10. The whole mixture was kept, under magnetic
stirring, at 20.degree. C., for 8 hours. The polymerization was
then quenched by the addition of 2 ml of methanol containing a few
drops of hydrochloric acid. The polymer obtained was subsequently
coagulated by the addition of 40 ml of a methanol solution
containing 4% of antioxidant Irganox.RTM. 1076 (Ciba) obtaining
0.603 g of polybutadiene having a content of 1,4-cis units >99%:
further characteristics of the process and of the polybutadiene
obtained are indicated in Table 1.
[0248] FIG. 2(b) shows the FT-IR spectrum of the polybutadiene
obtained.
Example 19
GL416
[0249] 2 ml of 1,3-butadiene, equal to about 1.4 g, were condensed,
at a low temperature (-20.degree. C.), in a 25 ml test-tube. 6.75
ml of toluene were then added and the temperature of the solution
thus obtained was brought to 20.degree. C. Methylaluminoxane (MAO)
in a toluene solution (6.3 ml; 1.times.10.sup.-2 moles, equal to
about 0.58 g) was then added, and subsequently the complex
NdCl.sub.3(L2) [sample GL360] (2.95 ml of a toluene solution at a
concentration equal to 2 mg/ml; 1.times.10.sup.-2 moles, equal to
about 5.9 mg) obtained as described in Example 10. The whole
mixture was kept, under magnetic stirring, at 20.degree. C., for
720 hours. The polymerization was then quenched by the addition of
2 ml of methanol containing a few drops of hydrochloric acid. The
polymer obtained was subsequently coagulated by the addition of 40
ml of a methanol solution containing 4% of antioxidant Irganox.RTM.
1076 (Ciba) obtaining 0.867 g of polybutadiene having a content of
1,4-cis units >99%: further characteristics of the process and
of the polybutadiene obtained are indicated in Table 1.
Example 20
A008
[0250] 2 ml of 1,3-butadiene, equal to about 1.4 g, were condensed,
at a low temperature (-20.degree. C.), in a 25 ml test-tube. 12.87
ml of heptane were then added and the temperature of the solution
thus obtained was brought to 20.degree. C. Di-iso-butyl-aluminium
hydride (DIBAH) (0.18 ml; 1 mmole, equal to about 144 mg) was then
added, and subsequently the complex NdCl.sub.3(L2) [sample GL360]
(2.95 ml of a toluene solution at a concentration equal to 2 mg/ml;
1.times.10.sup.-5 moles, equal to about 5.6 mg) obtained as
described in Example 10. The whole mixture was kept, under magnetic
stirring, at 20.degree. C., for 4 hours. The polymerization was
then quenched by the addition of 2 ml of methanol containing a few
drops of hydrochloric acid. The polymer obtained was subsequently
coagulated by the addition of 40 ml of a methanol solution
containing 4% of antioxidant Irganox.RTM. 1076 (Ciba) obtaining
0.603 g of polybutadiene having a content of 1,4-cis units >99%:
further characteristics of the process and of the polybutadiene
obtained are indicated in Table 1.
Example 21
GL596
[0251] 2 ml of 1,3-butadiene, equal to about 1.4 g, were condensed,
at a low temperature (-20.degree. C.), in a 25 ml test-tube. 6.9 ml
of heptane were then added and the temperature of the solution thus
obtained was brought to 20.degree. C. Tetra-iso-butyl-aluminoxane
(TIBAO) in a cyclohexane solution (6.2 ml; 1.times.10.sup.-2 moles,
equal to about 2.9 g) was then added, and subsequently the complex
NdCl.sub.3(L4) [sample P1888] (2.9 ml of a toluene solution at a
concentration equal to 2 mg/ml; 1.times.10.sup.-5 moles, equal to
about 5.8 mg) obtained as described in Example 11. The whole
mixture was kept, under magnetic stirring, at 20.degree. C., for 3
hours. The polymerization was then quenched by the addition of 2 ml
of methanol containing a few drops of hydrochloric acid. The
polymer obtained was subsequently coagulated by the addition of 40
ml of a methanol solution containing 4% of antioxidant Irganox.RTM.
1076 (Ciba) obtaining 0.668 g of polybutadiene having a content of
1,4-cis units >99%: further characteristics of the process and
of the polybutadiene obtamed are indicated in Table 1.
Example 22
P1942
[0252] 2 ml of 1,3-butadiene, equal to about 1.4 g, were condensed,
at a low temperature (-20.degree. C.), in a 25 ml test-tube. 6.8 ml
of toluene were then added and the temperature of the solution thus
obtained was brought to 20.degree. C. Methylaluminoxane (MAO) in a
toluene solution (6.3 ml; 1.times.10.sup.-2 moles, equal to about
0.58 g) was then added, and subsequently the complex NdCl.sub.3(L4)
[sample P1888] (2.9 ml of a toluene solution at a concentration
equal to 2 mg/ml; 1.times.10.sup.-5 moles, equal to about 5.8 mg)
obtained as described in Example 11. The whole mixture was kept,
under magnetic stirring, at 20.degree. C., for 20 hours. The
polymerization was then quenched by the addition of 2 ml of
methanol containing a few drops of hydrochloric acid. The polymer
obtained was subsequently coagulated by the addition of 40 ml of a
methanol solution containing 4% of antioxidant Irganox.RTM. 1076
(Ciba) obtaining 0.917 g of polybutadiene having a content of
1,4-cis units >99%: further characteristics of the process and
of the polybutadiene obtained are indicated in Table 1.
Example 23
P1962
[0253] 2 ml of 1,3-butadiene, equal to about 1.4 g, were condensed,
at a low temperature (-20.degree. C.), in a 25 ml test-tube. 12.92
ml of heptane were then added and the temperature of the solution
thus obtained was brought to 20.degree. C. Di-iso-butyl-aluminium
hydride (DIBAH) (0.18 ml; 1 mmole, equal to about 144 mg) was then
added, and subsequently the complex NdCl.sub.3(L4) [sample P1888]
(2.9 ml of a toluene solution at a concentration equal to 2 mg/ml;
1.times.10.sup.-5 moles, equal to about 5.8 mg) obtained as
described in Example 11. The whole mixture was kept, under magnetic
stirring, at 20.degree. C., for 30 hours. The polymerization was
then quenched by the addition of 2 ml of methanol containing a few
drops of hydrochloric acid. The polymer obtained was subsequently
coagulated by the addition of 40 ml of a methanol solution
containing 4% of antioxidant Irganox.RTM. 1076 (Ciba) obtaining
0.637 g of polybutadiene having a content of 1,4-cis units equal to
99%: further characteristics of the process and of the
polybutadiene obtained are indicated in Table 1.
[0254] FIG. 3 shows the .sup.1H-NMR and .sup.13C-NMR spectra of the
polybutadiene obtained.
Example 24
GL734
[0255] 2 ml of 1,3-butadiene, equal to about 1.4 g, were condensed,
at a low temperature (-20.degree. C.), in a 25 ml test-tube. 6.7 ml
of heptane were then added and the temperature of the solution thus
obtained was brought to 20.degree. C. Tetra-iso-butyl-aluminoxane
(TIBAO) in a cyclohexane solution (6.2 ml; 1.times.10.sup.-2 moles,
equal to about 2.9 g) was then added, and subsequently the complex
NdCl.sub.3(L6) [sample P1965] (3.1 ml of a toluene solution at a
concentration equal to 2 mg/ml; 1.times.10.sup.-5 moles, equal to
about 6.2 mg) obtained as described in Example 13. The whole
mixture was kept, under magnetic stirring, at 20.degree. C., for 12
hours. The polymerization was then quenched by the addition of 2 ml
of methanol containing a few drops of hydrochloric acid. The
polymer obtained was subsequently coagulated by the addition of 40
ml of a methanol solution containing 4% of antioxidant Irganox.RTM.
1076 (Ciba) obtaining 1.102 g of polybutadiene having a content of
1,4-cis units equal to 99.7%: further characteristics of the
process and of the polybutadiene obtained are indicated in Table
1.
[0256] FIG. 5 shows the .sup.1H-NMR and .sup.13C-NMR spectra of the
polybutadiene obtained.
Example 25
A001
[0257] 2 ml of 1,3-butadiene, equal to about 1.4 g, were condensed,
at a low temperature (-20.degree. C.), in a 25 ml test-tube. 6.8 ml
of toluene were then added and the temperature of the solution thus
obtained was brought to 20.degree. C. Methylaluminoxane (MAO) in a
toluene solution (6.3 ml; 1.times.10.sup.-2 moles, equal to about
0.58 g) was then added, and subsequently the complex NdCl.sub.3(L6)
[sample P1965] (3.1 ml of a toluene solution at a concentration
equal to 2 mg/ml; 1.times.10.sup.-5 moles, equal to about 6.2 mg)
obtained as described in Example 11. The whole mixture was kept,
under magnetic stirring, at 20.degree. C., for 110 hours. The
polymerization was then quenched by the addition of 2 ml of
methanol containing a few drops of hydrochloric acid. The polymer
obtained was subsequently coagulated by the addition of 40 ml of a
methanol solution containing 4% of antioxidant Irganox.RTM. 1076
(Ciba) obtaining 0.588 g of polybutadiene having a content of
1,4-cis units >99%: further characteristics of the process and
of the polybutadiene obtained are indicated in Table 1.
Example 26
A002
[0258] 2 ml of 1,3-butadiene, equal to about 1.4 g, were condensed,
at a low temperature (-20.degree. C.), in a 25 ml test-tube. 12.72
ml of heptane were then added and the temperature of the solution
thus obtained was brought to 20.degree. C. Di-iso-butyl-aluminium
hydride (DIBAH) (0.18 ml; 1 mmole, equal to about 144 mg) was then
added, and subsequently the complex NdCl.sub.3(L6) [sample P1965]
(3.1 ml of a toluene solution at a concentration equal to 2 mg/ml;
1.times.10.sup.-5 moles, equal to about 6.2 mg) obtained as
described in Example 13. The whole mixture was kept, under magnetic
stirring, at 20.degree. C., for 24 hours. The polymerization was
then quenched by the addition of 2 ml of methanol containing a few
drops of hydrochloric acid. The polymer obtained was subsequently
coagulated by the addition of 40 ml of a methanol solution
containing 4% of antioxidant Irganox.RTM. 1076 (Ciba) obtaining
0.605 g of polybutadiene having a content of 1,4-cis units >99%:
further characteristics of the process and of the polybutadiene
obtained are indicated in Table 1.
Example 27
GL732
[0259] 2 ml of 1,3-butadiene, equal to about 1.4 g, were condensed,
at a low temperature (-20.degree. C.), in a 25 ml test-tube. 6.55
ml of heptane were then added and the temperature of the solution
thus obtained was brought to 20.degree. C.
Tetra-iso-butyl-aluminoxane (TIBAO) in a cyclohexane solution (6.2
ml; 1.times.10.sup.-2 moles, equal to about 2.9 g) was then added,
and subsequently the complex NdCl.sub.3(L5) [sample P1963] (3.25 ml
of a toluene solution at a concentration equal to 2 mg/ml;
1.times.10.sup.-5 moles, equal to about 6.5 mg) obtained as
described in Example 12. The whole mixture was kept, under magnetic
stirring, at 20.degree. C., for 29 hours. The polymerization was
then quenched by the addition of 2 ml of methanol containing a few
drops of hydrochloric acid. The polymer obtained was subsequently
coagulated by the addition of 40 ml of a methanol solution
containing 4% of antioxidant Irganox.RTM. 1076 (Ciba) obtaining
0.462 g of polybutadiene having a content of 1,4-cis units equal to
99.9%: further characteristics of the process and of the
polybutadiene obtained are indicated in Table 1.
[0260] FIG. 2 (c) shows the FT-IR spectrum of the polybutadiene
obtained.
[0261] FIG. 6 shows the .sup.1H-NMR and .sup.13C-NMR spectra of the
polybutadiene obtained.
Example 28
A003
[0262] 2 ml of 1,3-butadiene, equal to about 1.4 g, were condensed,
at a low temperature (-20.degree. C.), in a 25 ml test-tube. 6.45
ml of toluene were then added and the temperature of the solution
thus obtained was brought to 20.degree. C. Methylaluminoxane (MAO)
in a toluene solution (6.3 ml; 1.times.10.sup.-2 moles, equal to
about 0.58 g) was then added, and subsequently the complex
NdCl.sub.3(L5) [sample P1963] (3.25 ml of a toluene solution at a
concentration equal to 2 mg/ml; 1.times.10.sup.-5 moles, equal to
about 6.5 mg) obtained as described in Example 12. The whole
mixture was kept, under magnetic stirring, at 20.degree. C., for
116 hours. The polymerization was then quenched by the addition of
2 ml of methanol containing a few drops of hydrochloric acid. The
polymer obtained was subsequently coagulated by the addition of 40
ml of a methanol solution containing 4% of antioxidant Irganox.RTM.
1076 (Ciba) obtaining 0.287 g of polybutadiene having a content of
1,4-cis units >99%: further characteristics of the process and
of the polybutadiene obtained are indicated in Table 1.
Example 29
A004
[0263] 2 ml of 1,3-butadiene, equal to about 1.4 g, were condensed,
at a low temperature (-20.degree. C.), in a 25 ml test-tube. 12.57
ml of heptane were then added and the temperature of the solution
thus obtained was brought to 20.degree. C. Di-iso-butyl-aluminium
hydride (DIBAH) (0.18 ml; 1 mmole, equal to about 144 mg) was then
added, and subsequently the complex NdCl.sub.3(L5) [sample P1963]
(3.25 ml of a toluene solution at a concentration equal to 2 mg/ml;
1.times.10.sup.-5 moles, equal to about 6.5 mg) obtained as
described in Example 12. The whole mixture was kept, under magnetic
stirring, at 20.degree. C., for 60 hours. The polymerization was
then quenched by the addition of 2 ml of methanol containing a few
drops of hydrochloric acid. The polymer obtained was subsequently
coagulated by the addition of 40 ml of a methanol solution
containing 4% of antioxidant Irganox.RTM. 1076 (Ciba) obtaining
0.435 g of polybutadiene having a content of 1,4-cis units >99%:
further characteristics of the process and of the polybutadiene
obtained are indicated in Table 1.
Example 30
GL733
[0264] 2 ml of 1,3-butadiene, equal to about 1.4 g, were condensed,
at a low temperature (-20.degree. C.), in a 25 ml test-tube. 6.65
ml of heptane were then added and the temperature of the solution
thus obtained was brought to 20.degree. C.
Tetra-iso-butyl-aluminoxane (TIBAO) in a cyclohexane solution (6.2
ml; 1.times.10.sup.-2 moles, equal to about 2.9 g) was then added,
and subsequently the complex NdCl.sub.3(L8) [sample P1964] (3.15 ml
of a toluene solution at a concentration equal to 2 mg/ml;
1.times.10.sup.-5 moles, equal to about 6.3 mg) obtained as
described in Example 14. The whole mixture was kept, under magnetic
stirring, at 20.degree. C., for 29 hours. The polymerization was
then quenched by the addition of 2 ml of methanol containing a few
drops of hydrochloric acid. The polymer obtained was subsequently
coagulated by the addition of 40 ml of a methanol solution
containing 4% of antioxidant Irganox.RTM. 1076 (Ciba) obtaining
0.280 g of polybutadiene having a content of 1,4-cis units equal to
99.6%: further characteristics of the process and of the
polybutadiene obtained are indicated in Table 1.
[0265] FIG. 2 (d) shows the FT-IR spectrum of the polybutadiene
obtained.
[0266] FIG. 4 shows the .sup.1H-NMR and .sup.13C-NMR spectra of the
polybutadiene obtained.
Example 31
A005
[0267] 2 ml of 1,3-butadiene, equal to about 1.4 g, were condensed,
at a low temperature (-20.degree. C.), in a 25 ml test-tube. 6.55
ml of heptane were then added and the temperature of the solution
thus obtained was brought to 20.degree. C. Methylaluminoxane (MAO)
in a toluene solution (6.3 ml; 1.times.10.sup.-2 moles, equal to
about 0.58 g) was then added, and subsequently the complex
NdCl.sub.3(L8) [sample P1964] (3.15 ml of a toluene solution at a
concentration equal to 2 mg/ml; 1.times.10.sup.-5 moles, equal to
about 6.3 mg) obtained as described in Example 14. The whole
mixture was kept, under magnetic stirring, at 20.degree. C., for
116 hours. The polymerization was then quenched by the addition of
2 ml of methanol containing a few drops of hydrochloric acid. The
polymer obtained was subsequently coagulated by the addition of 40
ml of a methanol solution containing 4% of antioxidant Irganox.RTM.
1076 (Ciba) obtaining 0.312 g of polybutadiene having a content of
1,4-cis units >99%: further characteristics of the process and
of the polybutadiene obtained are indicated in Table 1.
Example 32
A006
[0268] 2 ml of 1,3-butadiene, equal to about 1.4 g, were condensed,
at a low temperature (-20.degree. C.), in a 25 ml test-tube. 12.67
ml of heptane were then added and the temperature of the solution
thus obtained was brought to 20.degree. C. Di-iso-butyl-aluminium
hydride (DIBAH) (0.18 ml; 1 mmole, equal to about 144 mg) was then
added, and subsequently the complex NdCl.sub.3(L8) [sample P1964]
(3.15 ml of a toluene solution at a concentration equal to 2 mg/ml;
1.times.10.sup.-5 moles, equal to about 6.3 mg) obtained as
described in Example 14. The whole mixture was kept, under magnetic
stirring, at 20.degree. C., for 60 hours. The polymerization was
then quenched by the addition of 2 ml of methanol containing a few
drops of hydrochloric acid. The polymer obtained was subsequently
coagulated by the addition of 40 ml of a methanol solution
containing 4% of antioxidant Irganox.RTM. 1076 (Ciba) obtaining
0.420 g of polybutadiene having a content of 1,4-cis units >99%:
further characteristics of the process and of the polybutadiene
obtained are indicated in Table 1.
Example 33
Preparation of the Preformed Ternary Catalytic System
AlEt.sub.2Cl/Nd (OCOC.sub.2H.sub.15).sub.2/Al (.sup.iBu).sub.3
[0269] 15 ml of a heptane solution 0.05 M of neodymium
2-ethylhexanoate [Nd(OCOC.sub.2H.sub.15).sub.3]
(7.5.times.10.sup.-4 moles), 16.6 ml of heptane and 0.29 ml of
di-ethyl aluminium chloride (AlEt.sub.2Cl) (2.3.times.10.sup.-3
moles) were introduced, consecutively, into a 50 ml test-tube. Upon
the addition of di-ethyl aluminium chloride (AlEt.sub.2Cl), a
whitish suspension was immediately formed, which was kept, under
stirring, at room temperature, for 15 minutes.
Tri-isobutylaluminium [Al(.sup.iBu).sub.2] (5.63 ml;
2.25.times.10.sup.-2 moles) was subsequently added and the solution
obtained was left to age for 2 hours, under constant stirring, at
20.degree. C., obtaining a catalytic suspension having a
concentration of neodymium equal to 0.02 M.
Example 34
Comparative
[0270] 2 ml of 1,3-butadiene, equal to about 1.4 g, were condensed,
at a low temperature (-20.degree. C.), in a 25 ml test-tube. 7 ml
of heptane were then added and the temperature of the solution was
maintained at 20.degree. C. The preformed ternary catalyst
AlEt.sub.2Cl/Nd(OCOC.sub.2H.sub.15).sub.2/A(.sup.iBu).sub.2 (0.5
ml; 1.times.10.sup.-5 moles of Nd), obtained as described in
Example 33, was then added. The whole mixture was kept, under
magnetic stirring, at 20.degree. C., for 1.25 hours. The
polymerization was then quenched by the addition of 2 ml of
methanol containing a few drops of hydrochloric acid. The polymer
obtained was subsequently coagulated by the addition of 40 ml of a
methanol solution containing 4% of antioxidant Irganox.RTM. 1076
(Ciba) obtaining 0.780 g of polybutadiene having a content of
1,4-cis units equal to about 96%: further characteristics of the
process and of the polybutadiene obtained are indicated in Table
1.
[0271] FIG. 1 shows the .sup.1H-NMR spectrum of the polybutadiene
obtained.
[0272] FIG. 2 (a) shows the FT-IR spectrum of the polybutadiene
obtained.
TABLE-US-00001 TABLE 1 Polymerization of 1,3-butadiene with
catalytic systems prepared in situ Al/Ln M. (molar Conversion
N.sup.(a) P..sup.(b) T.sub.c.sup.(c) M.sub.w .times. 10.sup.-3 Ex.
ratio) (%) (h.sup.-1) (.degree. C.) (.degree. C.) (g .times.
mol.sup.-1) M.sub.w/M.sub.n .alpha..sup.(d) 15 1000 43.1 279 -2.2
-22.2 877 8.6 0.61 16 1000 53.9 12 -3.1 -24.2 440 5.1 0.55 17 100
30.7 99 -1.9 -21.8 680 9.5 0.63 18 1000 87.1 141 -1.5 -20.4 348
11.4 0.62 19 1000 61.9 2 -2.8 -23.9 276 6.6 0.56 20 100 34.8 45
-2.1 -21.9 650 4.9 0.60 21 1000 47.7 165 -1.6 -20.7 780 7.2 0.61 22
1000 65.5 14 -2.7 -22.9 620 8.9 0.55 23 100 45.5 39 -3.7 -28.5 650
5.8 0.62 24 1000 78.7 170 -1.3 -20.2 760 6.5 0.63 25 1000 42 9 -2.1
-21.7 220 2.8 0.57 26 100 43.2 47 -1.6 -20.7 580 5.1 0.59 27 1000
33 30 -1.1 -19.9 690 7.1 0.60 28 1000 20.5 5 -1.9 -22 195 3.5 0.56
29 100 31.1 13 -1.5 -20.5 570 5.2 0.62 30 1000 20 18 -1.4 -20.4 720
6 0.61 31 1000 22.3 5 -2.0 -222.1 320 3.7 0.56 32 100 30 13 -1.8
-21.5 560 4.8 0.62 34.sup.(e) 33 50 515 -6 -33 550 5 0.60
.sup.(a)number of moles of 1,3-butadiene polymerized per hour per
mole of lanthanide; .sup.(b)melting point; .sup.(c)crystallization
temperature; .sup.(d)linearity index of polybutadiene;
.sup.(e)polymerization carried out with the preformed catalyst
prepared as described in Example 33.
Example 35
GL760
[0273] 2 ml of isoprene, equal to about 1.36 g, were introduced, at
a temperature of 20.degree. C., into a 25 ml test-tube. 7 ml of
heptane were then added and the temperature of the solution was
maintained at 20.degree. C. Tetra-isobutyl-aluminoxane (TIBAO) in a
cyclohexane solution (6.22 ml; 1.times.10.sup.-2 moles, equal to
about 2.9 g) was then added, and subsequently the complex
NdCl.sub.3(L1) [sample GL380/P1891] (2.8 ml of a toluene solution
at a concentration equal to 2 mg/ml; 1.times.10.sup.-5 moles, equal
to about 5.6 mg) obtained as described in Example 9. The whole
mixture was kept, under magnetic stirring, at 20.degree. C., for 45
hours. The polymerization was then quenched by the addition of 2 ml
of methanol containing a few drops of hydrochloric acid. The
polymer obtained was subsequently coagulated by the addition of 40
ml of a methanol solution containing 4% of antioxidant Irganox.RTM.
1076 (Ciba) obtaining 1.129 g of polyisoprene having a content of
1,4-cis units equal to 98%: further characteristics of the process
and of the polyisoprene obtained are indicated in Table 2.
[0274] FIG. 7 shows the .sup.1H-NMR and .sup.13C-NMR spectra of the
polyisoprene obtained.
Example 36
GL800
[0275] 2 ml of isoprene, equal to about 1.36 g, were introduced, at
a temperature of 20.degree. C., into a 25 ml test-tube. 7 ml of
heptane were then added and the temperature of the solution was
brought to 50.degree. C. Tetra-isobutyl-aluminoxane (TIBAO) in a
cyclohexane solution (6.22 ml; 1.times.10.sup.-2 moles, equal to
about 2.9 g) was then added, and subsequently the complex
NdCl.sub.3(L1) [sample GL380/P1891] (2.8 ml of a toluene solution
at a concentration equal to 2 mg/ml; 1.times.10.sup.-5 moles, equal
to about 5.6 mg) obtained as described in Example 9. The whole
mixture was kept, under magnetic stirring, at 50.degree. C., for 23
hours. The polymerization was then quenched by the addition of 2 ml
of methanol containing a few drops of hydrochloric acid. The
polymer obtained was subsequently coagulated by the addition of 40
ml of a methanol solution containing 4% of antioxidant Irganox.RTM.
1076 (Ciba) obtaining 1.36 g of polyisoprene having a content of
1,4-cis units >98% and a glass transition temperature (T.sub.g)
equal to -66.0.degree. C.: further characteristics of the process
and of the polyisoprene obtained are indicated in Table 2.
[0276] FIG. 8 shows the DSC diagram of the polyisoprene
obtained.
Example 37
GL805
[0277] 2 ml of isoprene, equal to about 1.36 g, were introduced, at
a temperature of 20.degree. C., into a 25 ml test-tube. 13.2 ml of
heptane were then added and the temperature of the solution thus
obtained was brought to 50.degree. C. Di-iso-butyl-aluminium
hydride (DIBAH) (0.18 ml; 1 mmole, equal to about 144 mg) was then
added, and subsequently the complex NdCl.sub.3(L1) [sample
GL380/P1891] (2.8 ml of a toluene solution at a concentration equal
to 2 mg/ml; 1.times.10.sup.-5 moles, equal to about 5.6 mg) obtamed
as described in Example 9. The whole mixture was kept, under
magnetic stirring, at 50.degree. C., for 24 hours. The
polymerization was then quenched by the addition of 2 ml of
methanol containing a few drops of hydrochloric acid. The polymer
obtained was subsequently coagulated by the addition of 40 ml of a
methanol solution containing 4% of antioxidant Irganox.RTM. 1076
(Ciba) obtaining 1.36 g of polyisoprene having a content of 1,4-cis
units >98%: further characteristics of the process and of the
polyisoprene obtained are indicated in Table 2.
Example 38
P1885
[0278] 2 ml of isoprene, equal to about 1.36 g, were introduced, at
a temperature of 20.degree. C., into a 25 ml test-tube. 6.83 ml of
heptane were then added and the temperature of the solution was
maintained at 20.degree. C. Tetraiso-butyl-aluminoxane (TIBAO) in a
cyclohexane solution (6.22 ml; 1.times.10.sup.-2 moles, equal to
about 2.9 g) was then added, and subsequently the complex
NdCl.sub.3(L2) [sample GL360] (2.95 ml of a toluene solution at a
concentration equal to 2 mg/ml; 1.times.10.sup.-5 moles, equal to
about 5.9 mg) obtained as described in Example 10. The whole
mixture was kept, under magnetic stirring, at 20.degree. C., for 48
hours. The polymerization was then quenched by the addition of 2 ml
of methanol containing a few drops of hydrochloric acid. The
polymer obtained was subsequently coagulated by the addition of 40
ml of a methanol solution containing 4% of antioxidant Irganox.RTM.
1076 (Ciba) obtaining 0.447 g of polyisoprene having a content of
1,4-cis units >98%: further characteristics of the process and
of the polyisoprene obtained are indicated in Table 2.
Example 39
GL759
[0279] 2 ml of isoprene, equal to about 1.36 g, were introduced, at
a temperature of 20.degree. C., into a 25 ml test-tube. 6.9 ml of
heptane were then added and the temperature of the solution was
maintained at 20.degree. C. Tetraiso-butyl-aluminoxane (TIBAO) in a
cyclohexane solution (6.22 ml; 1.times.10.sup.-2 moles, equal to
about 2.9 g) was then added, and subsequently the complex
NdCl.sub.3(L4) [sample P1888] (2.9 ml of a toluene solution at a
concentration equal to 2 mg/ml; 1.times.10.sup.-5 moles, equal to
about 5.8 mg) obtained as described in Example 11. The whole
mixture was kept, under magnetic stirring, at 20.degree. C., for 45
hours. The polymerization was then quenched by the addition of 2 ml
of methanol containing a few drops of hydrochloric acid. The
polymer obtained was subsequently coagulated by the addition of 40
ml of a methanol solution containing 4% of antioxidant Irganox.RTM.
1076 (Ciba) obtaining 0.307 g of polyisoprene having a content of
1,4-cis units >98%: further characteristics of the process and
of the polyisoprene obtained are indicated in Table 2.
Example 40
GL799
[0280] 2 ml of isoprene, equal to about 1.36 g, were introduced, at
a temperature of 20.degree. C., into a 25 ml test-tube. 6.9 ml of
heptane were then added and the temperature of the solution was
brought to 50.degree. C. Tetraiso-butyl-aluminoxane (TIBAO) in a
cyclohexane solution (6.22 ml; 1.times.10.sup.-2 moles, equal to
about 2.9 g) was then added, and subsequently the complex
NdCl.sub.3(L4) [sample P1888] (2.9 ml of a toluene solution at a
concentration equal to 2 mg/ml; 1.times.10.sup.-5 moles, equal to
about 5.8 mg) obtained as described in Example 11. The whole
mixture was kept, under magnetic stirring, at 50.degree. C., for
22.5 hours. The polymerization was then quenched by the addition of
2 ml of methanol containing a few drops of hydrochloric acid. The
polymer obtained was subsequently coagulated by the addition of 40
ml of a methanol solution containing 4% of antioxidant Irganox.RTM.
1076 (Ciba) obtaining 1.36 g of polyisoprene having a content of
1,4-cis units >98% and a glass transition temperature (T.sub.g)
equal to -66.3.degree. C.: further characteristics of the process
and of the polyisoprene obtained are indicated in Table 2.
[0281] FIG. 9 shows the DSC diagram of the polyisoprene
obtained.
Example 41
GL802
[0282] 2 ml of isoprene, equal to about 1.36 g, were introduced, at
a temperature of 20.degree. C., into a 25 ml test-tube. 12.92 ml of
heptane were then added and the temperature of the solution was
brought to 50.degree. C. Di-isobutyl-aluminium hydride (DIBAH)
(0.18 ml; 1 mmole, equal to about 144 mg) was then added, and
subsequently the complex NdCl.sub.3(L4) [sample P1888] (2.9 ml of a
toluene solution at a concentration equal to 2 mg/ml;
1.times.10.sup.-5 moles, equal to about 5.8 mg) obtained as
described in Example 11. The whole mixture was kept, under magnetic
stirring, at 50.degree. C., for 24 hours. The polymerization was
then quenched by the addition of 2 ml of methanol containing a few
drops of hydrochloric acid. The polymer obtained was subsequently
coagulated by the addition of 40 ml of a methanol solution
containing 4% of antioxidant Irganox.RTM. 1076 (Ciba) obtaining
1.36 g of polyisoprene having a content of 1,4-cis units >98%:
further characteristics of the process and of the polyisoprene
obtained are indicated in Table 2.
Example 42
Comparative
[0283] 2 ml of isoprene, equal to about 1.36 g, were introduced, at
a temperature of 20.degree. C., into a 25 ml test-tube. 7 ml of
heptane were then added and the temperature of the solution was
maintained at 20.degree. C. The preformed ternary catalyst
AlEt.sub.2Cl/Nd (OCOC.sub.7H.sub.15).sub.3/Al (.sup.iBU).sub.3 (0.5
ml; 1.times.10.sup.-5 moles of Nd), obtained as described in
Example 33, was then added. The whole mixture was kept, under
magnetic stirring, at 20.degree. C., for 6 hours. The
polymerization was then quenched by the addition of 2 ml of
methanol containing a few drops of hydrochloric acid. The polymer
obtained was subsequently coagulated by the addition of 40 ml of a
methanol solution containing 4% of antioxidant Irganox.RTM. 1076
(Ciba) obtaining 0.544 g of polyisoprene having a content of
1,4-cis units equal to about 94%: further characteristics of the
process and of the polyisoprene obtained are indicated in Table
2.
[0284] FIG. 1 shows the .sup.1H-NMR spectrum of the polyisoprene
obtained.
TABLE-US-00002 TABLE 2 Polymerization of isoprene with catalytic
systems prepared in situ Al/Ln (molar Conversion N.sup.(a) M.sub.w
.times. 10.sup.-3 T.sub.g.sup.(b) Example ratio) (%) (h.sup.-1) (g
.times. mol.sup.-1) M.sub.w/M.sub.n (.degree. C.) 35 1000 83 37 814
4.5 -66.4 36 1000 100 87 680 4.8 -66.0 37 100 100 83 600 6.2 -66.0
38 1000 32.9 14 902 6 -65.5 39 1000 22.6 10 945 5.3 -65.8 40 1000
100 89 820 4.9 -66.3 41 100 100 83 790 5.5 -65.7 42 33 40 133 400 4
-62.1 NR.sup.(c) -- -- -- -- -- -66.2 .sup.(a)number of moles of
isoprene polymerized per hour per mole of lanthanide; .sup.(b)glass
transition temperature; .sup.(c)natural rubber (FIG. 10 shows the
DSC diagram of natural rubber).
* * * * *
References