Cyclic ether polymerization using silicon compound accelerators

When selected silicon compounds are added to cationic polymerizations of cyclic ethers such as oxiranes and tetrahydrofurans, the rate of polymerization is often increased, and novel polyethers are produced. The polyether products are useful as monomers and macromonomers, particularly after hydrolysis of silicon containing end groups.

FIELD OF THE INVENTION 
Disclosed herein is a process for the cationic polymerization of cyclic 
ethers, wherein an accelerator (co-catalyst) is a selected silicon 
compound. Polyethers, some of which are novel compositions, are produced 
rapidly, often in good yields. 
TECHNICAL BACKGROUND 
Cyclic ethers are polymerized by various means to give products of 
widespread utility. For instance, ethylene oxide is polymerized to 
polyethylene oxide which is useful for (in lower molecular grades) 
ceramics, cosmetics, lubricants, polyurethanes, (and in higher molecular 
weight grades), packaging film, denture adhesives, lubricants, and 
flocculation, and tetrahydrofuran (THF) is polymerized to 
poly(tetramethylene ether) glycol which is useful in the preparation of 
Spandex fibers, polyurethane resins useful in elastomeric parts, and 
thermoplastic elastomers useful for molding various mechanical parts. 
Therefore, improved methods of making these polymers are sought. 
One general method for the polymerization of cyclic ethers is the so-called 
cationic mechanism. In this type of polymerization, an acid, usually a 
Bronsted or Lewis acid, is used as the catalyst. Accelerators (sometimes 
also called co-catalysts) are sometimes used, and these can affect both 
the rate and yield of the polymerization, as well as the structure (for 
example end groups) of the polyether produced. Disclosed herein is a new 
class of accelerators for the cationic polymerization of cyclic ethers. 
J. S. Hrkach, et al., Macromolecules, vol. 23, p. 4042-4046 (1990) describe 
the polymerization of tetrahydrofuran using trimethylsilyl 
trifluoromethanesulfonate as the catalyst. 
German Patent Application 2,459,163 describes the polymerization of THF 
using a combination of ferric chloride and carboxylic anhydride as 
catalyst. 
U.S. Pat. Nos. 5,084,586 and 5,124,417 describe the cationic polymerization 
of various monomers, including cyclic ethers, using onium cations, whose 
corresponding anions are fluororalkylsulfatometallates. Onium ion 
catalyzed cationic polymerizations are well known cationic 
polymerizations. 
Japanese Patent Application 51-82397 describes the polymerization of 
tetrahydrofuran using a combination of fluorosulfonic acid and a 
carboxylic acid as catalysts. 
T. Misaki, et al., Nippon Kagaku Kaishi, p. 168-174 (1973) report on the 
polymerization of THF using a combination of metal aceylacetonates and 
acetyl chloride. 
With the exception of J. R. Hrkach, et al., none of these references 
mentions the use of silicon compounds as catalysts or accelerators in the 
polymerizations. 
SUMMARY OF THE INVENTION 
This invention concerns a process for cationic polymerization of cyclic 
ethers by contacting a cationic catalyst for the polymerization of cyclic 
ether with one or more oxiranes, oxetanes, tetrahydrofurans, oxepanes, 
1,3-dioxolanes or 1,3,5-trioxanes, to produce a polyether, wherein the 
improvement comprises an accelerator in contact with the polymerization 
mass, said accelerator having bound to silicon a group whose conjugate 
acid has a pKa in water of less than about 16, and provided that: 
said accelerator does not significantly react with said cationic catalyst 
for said cationic polymerization in the absence of said oxiranes, 
oxetanes, tetrahydrofurans, oxepanes, 1,3-dioxolanes or 1,3,5-trioxanes; 
and 
said accelerator does not by itself cause polymerization of said oxiranes, 
oxetanes, tetrahydrofurans, oxepanes, 1,3-dioxolanes or 1,3,5-trioxanes to 
produce a polyether. 
This invention also concerns a process for the production of polyethers, 
comprising, contacting at about -80.degree. C. to about 130.degree. C. a 
Bronsted or Lewis acid with one or more oxiranes, oxetanes, 
tetrahydrofurans, oxepanes, 1,3-dioxolanes or 1,3,5-trioxanes, and an 
accelerator, wherein said accelerator is a silicon compound wherein a 
group whose conjugate acid has a pKa of less than 16 in water is bound to 
a silicon atom, and provided that: 
said accelerator does not significantly react with said Bronsted or Lewis 
acid in the absence of said oxiranes, oxetanes, tetrahydrofurans, 
oxepanes, 1,3-dioxolanes or 1,3,5-trioxanes; and 
said accelerator does not by itself cause polymerization of said oxiranes, 
oxetanes, tetrahydrofurans, oxepanes, 1,3-dioxolanes or 1,3,5-trioxanes to 
produce a polyether. 
This invention also concerns a polyether of the structure 
EQU Y--{A--[CHR.sup.1 (CR.sup.2 R.sup.3).sub.n (CHR.sup.4).sub.p --O].sub.q 
--B}.sub.m or Z--{S--[O--CHR.sup.1 (CR.sup.2 R.sup.3).sub.n 
(CHR.sup.4).sub.p ].sub.q --T}.sub.r 
wherein: 
Y is a hydrocarbyl or substituted hydrocarbyl group with m free bonds; 
Z is a hydrocarbyl, substituted hydrocarbyl, siloxy or silyl group with r 
free bonds; 
A is a group whose conjugate acid has a pKa of less than 16 in water; 
T is a group whose conjugate acid has a pKa of less than 16 in water; 
S is a silyl group bound to a terminal oxygen of a polyether segment and to 
Z; 
B is a silyl group bound to a terminal oxygen of a polyether segment; 
each R.sup.1, R.sup.2, R.sup.3, and R.sup.4 is independently hydrogen or 
hydrocarbyl containing 1 to 20 carbon atoms; 
each n is independently 0, 1 or 2; 
m is an integer of 1 to 5; 
each p is independently 0 or 1; 
each q is independently an integer of 3 or more; 
r is an integer of one or more; 
provided that when p is 0, n is also 0.

DETAILS OF THE INVENTION 
In the polymerization process described herein one or more cyclic ethers, 
oxiranes, oxepanes, oxetanes, tetrahydrofurans, 1,3,5-trioxanes and 
1,3-dioxolanes may be polymerized to form polyethers. Oxirane (more 
commonly called epoxide) is herein given it usual structure, a saturated 
three membered ring containing two carbon atoms and one oxygen atom. 
Oxetane is also given its common meaning, a saturated four membered ring 
containing 3 carbon atoms and one oxygen atom. The term 1,3-dioxolane 
means a saturated 5 membered ring which contains two oxygen atoms 
separated by 1 carbon atom. The term 1,3,5-trioxane means a six membered 
ring containing 3 oxygen atoms in which the oxygen atoms and carbons atoms 
are alternated. The term oxepane means a membered ring containing one 
oxygen atom. The terms oxirane, oxetane, oxepane, 1,3-dioxolane, 
1,3,5-trioxane and tetrahydrofuran include compounds containing those ring 
systems which are substituted with hydrocarbyl or hydrocarbylene groups 
containing 1 to 20 carbon atoms. The hydrocarbylene groups form 
carbocyclic rings, which include bicyclic, tricyclic, etc., systems. By a 
hydrocarbylene group herein is meant a divalent radical containing carbon 
and hydrogen which is part of a carbocyclic ring. 
Useful protic acids include perfluoroalkylsulfonic acids including 
trifluoromethanesulfonic acid, fluorosulfonic acid a perfluoroinated 
polymer containing sulfonic acid groups such as Nafion, heteropoly acids, 
acidic clays, and other very strong acids. Useful Lewis acids include 
selected metal salts of perfluoroalkylsulfonic acids, particularly those 
of trifluoromethanesulfonic acid (herein sometimes referred to as 
triflates), and onium salts such as oxonium salts. Preferred catalysts are 
metal triflates and other perfluoroalkylsulfonates, particularly those of 
divalent strontium, barium, cobalt, rhodium,, iridium, palladium, 
platinum, chromium, zinc, cadmium or mercury; trivalent scandium, yttrium, 
a rare earth metal, arsenic, antimony, bismuth, gold, iron, ruthenium, 
osmium, aluminum, gallium, indium or thulium; tetravalent titanium, 
zirconium, hafnium, molybdenum, silicon, germanium, tin, or lead; 
pentavalent rhenium, vanadium, niobium or tantalum; and hexavalent 
tungsten. Preferred triflates are those of strontium, scandium yttrium, 
the rare earth metals, titanium, zirconium, hafnium, vanadium, niobium, 
tantalum, chromium, molybdenum, tungsten, rhenium, iron, ruthenium, 
palladium, copper, gold, zinc, tin and bismuth. More preferred metals are 
yttrium, the rare earth metals, scandium, zirconium, tantalum, zinc and 
bismuth. Especially preferred metals are yttrium, ytterbium, dysprosium, 
erbium, neodymium, lanthanum, scandium, zirconium, tantalum, zinc and 
bismuth. Another preferred metal is "mischmetall", which is a mixture of 
rare earth metals as obtained from the ore. All of the preferred metals 
are in the valence states noted at the beginning of this paragraph. By a 
triflate or perfluoroalkylsulfonate herein is meant a compound which 
contains at least one triflate or perftuoroalkylsulfonate anion. 
By the rare earths herein is meant lanthanum, cerium, praeseodymium, 
neodymium, promethium, samarium, europium, gadolinium, terbium, 
dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. 
The polymerization may be run at a temperature of about -80.degree. C. to 
about 130.degree. C., preferably about 0.degree. C. to about 110.degree. 
C. If this temperature is above the boiling point of the cyclic ether 
monomer, a pressure vessel may be used. The temperature range used in the 
polymerization will be dependent on many variables, particularly the 
reactivity and stability of the cationic catalyst used. Particular 
temperatures for various catalysts can be found in references wherein 
those catalysts are described. An inert solvent such as di-n-butyl ether, 
diethyl ether or toluene may be used, but it is preferred if solvents are 
not present. Protic compounds such as water, methanol and ethanol should 
preferably not be present, and it is convenient to exclude them by drying 
the starting materials and keeping the process under an inert dry gas such 
as nitrogen or dry air. As in most chemical processes, the ingredients 
should be mixed at least initially. Continued agitation is preferred to 
assure that the process materials remain well mixed, and to avoid 
overheating. The polymerization is mildly exothermic. If the 
polymerization temperature goes up appreciably, refluxing of the monomer 
may be used to help cool the process. Dependent on the particular catalyst 
used, the process may be run in batch, semibatch and/or continuous modes. 
The compounds used as accelerators herein are silicon compounds in which 
one or more silicon atoms is bound to a group whose conjugate acid has a 
pKa of 16 or less in water which is referred to in claim 6 as a "first 
group". In essence, if one labels the group bound to silicon is whose 
conjugate acid has a pKa of 16 or less in water as "Q.about..about." (or 
simply "Q" if monovalent), such as in 
EQU Si--Q.about..about. (I), 
then the conjugate acid of Q.about..about. is .about..about.QH, where a 
hydrogen atom has taken the place of the silicon atom. .about..about.Q 
groups may be "monovalent (have no "tail"), for example halide ion. The 
wavy line on Q represents another group bound to a Q which is "divalent". 
For instance when Q.about..about. is acetoxy, .about..about.QH is acetic 
acid, and the wavy line represents the methyl group of the acetic acid. 
However, an accelerator molecule may have more than one Q.about..about. 
group, and/or more than one silicon atom which is bound to a 
Q.about..about. group as in 
EQU .about..about.Q--Si--CH.sub.2 CH.sub.2 --Si--Q.about. or 
.about..about.Q--Si--Q.about..about. (II) 
and 
EQU --Si--Q.about..about.Q--Si-- (III). 
Thus a silicon compound which contains a group (Q.about..about.) whose 
conjugate acid has a pKa in water of 16 or less can be mono- or 
polyfunctional accelerator. Assuming the conjugate acid of each 
Q.about..about. group in the molecule has a pKa in water of 16 or less, 
each can take part in the polymerization reaction. If different types of 
Q.about..about. groups are involved, they may react at different rates. 
Similarly, if the environment around silicon atoms which are bound to 
Q.about..about. groups in the same molecule are different, the 
Q.about..about. groups may react at differing rates. 
Since it is difficult or impossible to measure the pKa of acids which are 
greater than about 14 in water, such pKa's can be estimated by 
extrapolation from another solvent such as dimethylsulfoxide. It is 
preferred if a Q.about..about. group (or the group which has a pKa of less 
than about 16 which is bonded to a silicon atom) having a conjugate acid 
with a pKa of less than 7 in water is used, more preferred if it has a pKa 
of less than 6, and most preferred if it has a pKa of .about.4 to 5. 
Useful Q.about..about. groups (mono- and divalent) include chloro, bromo, 
iodo, acyloxy [--C(O)O--], aryloxy, alkoxy, nitrile (--C.tbd.N), and 
phosphato [O.dbd.P(--O--).sub.3 ]. Preferred Q.about..about. groups are 
chloro, bromo, and acyloxy [--C(O)O--]. Specific preferred Q groups are 
trifluoroacetate, acetate, formate, terephthalate, adipate, bromoacetate, 
chloroacetate, and fluoroacetate. 
The novel products of the polymerization are 
EQU Z--{A--[CHR.sup.1 (CR.sup.2 R.sup.3).sub.n (CHR.sup.4).sub.p --O].sub.q 
--B}.sub.m or Y--{S--[O--CHR.sup.1 (CR.sup.2 R.sup.3).sub.n 
(CHR.sup.4).sub.p ].sub.q --T}.sub.r, 
wherein all the symbols are as described above (in these formulas all 
symbols are nonstandard, except for the numbers, C which is carbon, H 
which is hydrogen, and O which is oxygen). When m or r is 1, the polyether 
is made using a compound such as (I) as the accelerator. When A and B are 
present and m is 2, then a compound such as (III) would have been used as 
the accelerator, and when S and T are present and r is 2, then a compound 
such as (II) would have been used as the accelerator. Polyethers where m 
is greater than 2 can be made by using accelerators analogous to those 
described immediately above. In other words, m in the product polyether 
formulas is equal to the number of A groups (synonymous in this instance 
to Q.about..about.), and r is equal to the number of B groups (synonymous 
in this instance to silicon atoms which are bonded to Q.about..about. 
groups), which are bonded to Z and Y respectively. 
The accelerators herein should not "react significantly" with the 
polymerization catalyst, nor should the accelerator itself (in the absence 
of catalyst) cause polymerization of the cyclic ether. By not reacting 
significantly means that little of the catalyst and accelerator react 
before the polymerization is carried out. In other words, if the reaction 
between the catalyst and accelerator is much slower than the 
polymerization, significant reaction would not have taken place. 
Open bonds to silicon atoms herein, that is where the group bonded to 
silicon is not specified, are bonds to a group whose conjugate acid has a 
pKa of 16 or less (in other words a Q.about..about. group), a hydrocarbyl 
or substituted hydrocarbyl group wherein the substituents are inert under 
the polymerization process conditions, a siloxy group or a silyl group. 
The silicon compound herein may be a polymer, such as a polysiloxane or a 
polysilane which has Q.about..about. groups on one, a few, or many of the 
silicon atoms in the polymer. 
In preferred polyethers produced by the process described herein, n is 2, 
or n is 0 and p is 1, or n and p are both 0. In other preferred polyethers 
all of R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are hydrogen, or all of 
R.sup.2, R.sup.3 and R.sup.4 are hydrogen and R.sup.1 is alkyl containing 
1 to 4 carbon atoms, more preferably R.sup.1 is methyl. It is especially 
preferred when n is 2 and all of R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are 
hydrogen, or all of R.sup.2, R.sup.3 and R.sup.4 are hydrogen and R.sup.1 
is alkyl containing 1 to 4 carbon atoms, more preferably R.sup.1 is 
methyl. In all of the polyether products, it is preferred if m is 1 or if 
m is 2, 3, 4, or 5, and especially preferred if m is 2. Since the number r 
may represent the number of Q.about..about. groups in a polysiloxane or 
polysilane its value is in principle unlimited, but it is preferred if it 
is less than 3000. However, it is more preferred if r is 1 or 2, or 
between 5 and 500. It is also preferred if q is 5 or more, more preferred 
if q is 8 or more, especially preferred if q is 10 or more, and 
particularly preferred if q is 25 or more. Although there is no upper 
limit on q, it is preferred in all instances if q is less than 500, and 
more preferred if q is less than 100. By hydrocarbyl herein is meant a 
univalent radical containing only carbon and hydrogen. 
Some of these polyethers are made from cyclic ethers of the formula 
##STR1## 
wherein all the symbols are as described above. In preferred starting 
cyclic ethers n, R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are as described 
above for the products of the polymerization of the cyclic ethers. 
In the polyethers produced by the instant process, using the silicon 
containing accelerators, one end group may a relatively inert group such 
as a halogen (not fluorine), ester or ether, while the other end group may 
be a "silicon ether" often called an alkoxysilane In other polyethers 
alkoxysilane may be present internally in the polyether chain while the 
end groups are halogen (not fluorine), ester or ether, or there may be 
internal ester or ether (derived from the accelerator) groups and 
alkoxysilane end groups. In all of these polyethers, if the relatively 
easily hydrolyzed alkoxysilane groups are hydrolyzed, the resulting 
polymer may have hydroxyl groups on both ends and thereby be useful as a 
monomer, or have a hydroxyl group on one end and be useful as a 
macromonomer. In addition the silylated and unsilylated polyethers 
produced herein are also useful in many of the other uses listed in the 
Technical Background section. 
In the Examples, the following abbreviations and names are used: 
GPC--gel permeation chromatography 
Mn--number average molecular weight 
Mw--weight average molecular weight 
Nafion--A perfluorinated polymer which contains perfluorinated side chains 
which have sulfonic acid groups and available from E. I du Pont de Nemours 
and Co., Wilmington, Del., U.S.A. 
PD--polydispersity (Mw/Mn) 
PS--polystyrene 
THF--tetrahydrofuran 
EXAMPLE 1 
Polymerization of THF with Trimethylsilyl Acetate and Ytterbium Triflate 
In a dry box, ytterbium triflate (3.00 g) was added to a 100 mL round 
bottom flask equipped with a stirring bar. The flask was sealed with a 
rubber septum and removed from the dry box. After the attachment of a 
nitrogen bleed THF (20.00 mL) was added followed by trimethylsilyl acetate 
(2.00 mL). After 60 minutes the polymerization was terminated by the 
addition of water (10 mL), THF (25 mL) and diethyl ether (25 mL). The 
resulting organic phase was separated, concentrated at reduced pressure 
and then dried under vacuum. Polymer yield: 10.95 g. GPC analysis: 
Mn=10200, Mw=22400, PD=2.18 (PS STD.). 
EXAMPLE 2 
Polymerization of THF with Dimethyldiformoxysilane and Ytterbium Triflate 
In a dry box, ytterium triflate (1.50 g) was added to each of three 
separate oven dried 100 mL RB flasks equipped with stirring bars. The 
flasks were sealed with rubber septa and then removed from the dry box. 
Nitrogen bleeds were attached and THF (10.00 mL) and 
dimethyldiformoxysilane (3.50 mL) were added to each flask. After 15, 30, 
and 60 minutes a polymerization was terminated via the addition of water 
(25 mL), ether (25 mL) and THF (50 mL). The resulting organic phases were 
separated, concentrated at reduced pressure and then dried under vacuum. 
Polymer yields and GPC analyses: 
______________________________________ 
Polymer. Polymer Mn 
Time Yield (g) 
(PS STD.) Mw PD 
______________________________________ 
15 mins. 4.48 6280 10200 1.62 
30 mins. 5.42 5730 9800 1.71 
60 mins. 5.21 5380 9530 1.77 
______________________________________ 
EXAMPLE 3 
Polymerization of THF with Trimethylsilyl Tifluoroacetate and Ytterbium 
Triflate 
In a dry box, ytterbium triflate (3.00 g) was added to a 100 mL round 
bottom flask equipped with a stirring bar. The flask was sealed with a 
rubber septum and removed from the dry box. After the attachment of a 
nitrogen bleed THF (20.00 mL) was added followed by 
trimethylsilyltrifluoroacetate (2.00 mL) After 60 minutes the 
polymerization was terminated by the addition of water (10 mL), THF (25 
mL) and diethyl ether (25 mL). The resulting organic phase was separated, 
concentrated at reduced pressure and then dried under vacuum. Polymer 
yield: 10.34 g. GPC analysis: Mn=7240, Mw=15600, PD=2.16 (PS STD.). 
EXAMPLE 4 
Polymerization of THF with Bis(trimethylsilyl) Terephthate and Ytterbium 
Triflate 
In a dry box, ytterbium triflate (3.00 g) was added to a 100 mL round 
bottom flask equipped with a stirring bar. The flask was sealed with a 
rubber septum and removed from the dry box. After the attachment of a 
nitrogen bleed THF (20.00 mL) was added followed by his (trimethylsilyl) 
terephthate (4.00 mL). After 60 minutes the polymerization was terminated 
by the addition of water (10 mL), THF (25 mL) and diethyl ether (25 mL). 
The resulting organic phase was washed with water (2.times.50 mL) 
separated, concentrated at reduced pressure and then dried under vacuum. 
Polymer yield: 13.86 g. GPC analysis: Mn=32700, Mw=67400, PD=2.06 (PS 
STD.). 
EXAMPLE 5 
Polymerization of THF with Trimethylsilylcyanide and Ytterbium Triflate 
In a dry box, ytterbium triflate (3.00 g) was added to a 100 mL round 
bottom flask equipped with a stirring bar. The flask was sealed with a 
rubber septum and removed from the dry box. After the attachment of a 
nitrogen bleed THF (20.00 mL) was added followed by trimethylsilylcyanide 
(2.00 mL). After 60 minutes the polymerization was terminated by the 
addition of water (10 mL), THF (25 mL) and diethyl ether (25 mL). The 
resulting organic phase was separated, concentrated at reduced pressure 
and then dried under vacuum. Polymer yield: 0.98 g. GPC analysis: 
Mn=16400, Mw=25200, PD=1.57 (PS STD.). 
EXAMPLE 6 
Polymerization of THF with Trimethylsilyl Trimethylsiloxyacetate and 
Ytterbium Triflate 
In a dry box, ytterbium triflate (3.00 g) was added to a 100 mL round 
bottom flask equipped with a stirring bar. The flask was sealed with a 
rubber septum and removed from the dry box. After the attachment of a 
nitrogen bleed THF (20.00 mL) was added followed by trimethylsilyl 
trimethylsiloxyacetate (2.00 mL). After 60 minutes the polymerization was 
terminated by the addition of water (10 mL), THF (25 mL) and diethyl ether 
(25 mL). The resulting organic phase was separated, concentrated at 
reduced pressure and then dried under vacuum. Polymer yield: 3.36 g. GPC 
analysis: Mn=51900, Mw=67400, PD=1.30 (PS STD.). 
EXAMPLE 7 
Polymerization of THF with Bis(trimethylsilyl) Sebacate and Ytterbium 
Triflate 
In a dry box, ytterbium triflate (3.00 g) was added to a 100 mL round 
bottom flask equipped with a stirring bar. The flask was sealed with a 
rubber septum and removed from the dry box. After the attachment of a 
nitrogen bleed THF (20.00 mL) was added followed by bis(trimethylsilyl) 
sebacate (5.00 mL). After 60 minutes the polymerization was terminated by 
the addition of water (10 mL), THF (25 mL) and diethyl ether (25 mL). The 
resulting organic phase was washed with water (2.times.50 mL) separated, 
concentrated at reduced pressure and then dried under vacuum. Polymer 
yield: 12.35 g. GPC analysis: Mn=14400, Mw=27400, PD=1.90 (PS STD.). 
EXAMPLE 8 
Polymerization of THF with Bis(trimethylsilyl) Adipate and Ytterbium 
Triflate 
In a dry box, ytterbium triflate (3.00 g) was added to a 100 mL round 
bottom flask equipped with a stirring bar. The flask was sealed with a 
rubber septum and removed from the dry box. After the attachment of a 
nitrogen bleed THF (20.00 mL) was added followed by bis(trimethylsilyl) 
adipate (5.00 mL). After 60 minutes the polymerization was terminated by 
the addition of water (10 mL), THF (25 mL) and diethyl ether (25 mL). The 
resulting organic phase was washed with water (2.times.50 mL) separated, 
concentrated at reduced pressure and then dried under vacuum. Polymer 
yield: 11.15 g. GPC analysis: Mn=11700, Mw=20700, PD=1.77 (PS STD.). 
EXAMPLE 9 
Polymerization of THF with Vinylmethyl-diacetoxysilane and Ytterbium 
Triflate 
In a dry box, ytterbium triflate (3.00 g) was added to a 100 mL round 
bottom flask equipped with a stirring bar. The flask was sealed with a 
rubber septum and removed from the dry box. After the attachment of a 
nitrogen bleed THF (20.00 mL) was added followed by 
vinylmethyl-diacetoxysilane (5.00 mL). After 60 minutes the polymerization 
was terminated by the addition of water (10 mL), THF (25 mL) and diethyl 
ether (25 mL). The resulting organic phase was washed with water 
(2.times.50 mL) separated, concentrated at reduced pressure and then dried 
under vacuum. Polymer yield: 12.81 g. GPC analysis: Mn=5180, Mw=8900, 
PD=1.72 (PS STD.). 
EXAMPLE 10 
Polymerization of THF with Methyltriacetoxysilane and Ytterbium Triflate 
In a dry box, ytterbium triflate (3.00 g) was added to a 100 mL round 
bottom flask equipped with a stirring bar. The flask was sealed with a 
rubber septum and removed from the dry box. After the attachment of a 
nitrogen bleed THF (20.00 mL) was added followed by methyltriacetoxysilane 
(5.00 mL). After 60 minutes the polymerization was terminated by the 
addition of water (10 mL), THF (25 mL) and diethyl ether (25 mL). The 
resulting organic phase was washed with water (2.times.50 mL) separated, 
concentrated at reduced pressure and then dried under vacuum. Polymer 
yield: 10.83 g. GPC analysis: Mn=4490, Mw=8470, PD=1.89 (PS STD.). 
EXAMPLE 11 
Polymerization of THF with Methyltriacetoxysilane and 
Bis(n-cyclopentadienyl)tetrahydrofuran-bis(trifluoromethanesulfonato)hafni 
um 
In a dry box, 
bis(n-cyclopentadienyl)tetrahydrofuran-bis(trifluoromethanesulfonato)hafni 
um (0.50 g) was added to a 100 mL round bottom flask equipped with a 
stirring bar. The flask was sealed with a rubber septum and removed from 
the dry box. After the attachment of a nitrogen bleed THF (20.00 mL) was 
added followed by methyltriacetoxysilane (2.50 mL). After 60 minutes the 
polymerization was terminated by the addition of water (10 mL), THF (25 
mL) and diethyl ether (25 mL). The resulting organic phase was washed with 
water (2.times.50 mL) separated, concentrated at reduced pressure and then 
dried under vacuum. Polymer yield: 1.20 g. GPC analysis: Mn=14600, 
Mw=17400, PD=1.19 (PS STD.). 
EXAMPLE 12 
Polymerization of THF with Bis(trimethylsilyl)adipate and 
Bis(n-cyclopentadienyl)tetrahydrofuran-bis(trifluoromethanesulfonato)zirco 
nium 
In a dry box, bis(n-cyclopentadienyl) 
tetrahydrofuran-bis(trifluoromethanesulfonato) zirconium (0.50 g) was 
added to a 100 mL round bottom flask equipped with a stirring bar. The 
flask was sealed with a rubber septum and removed from the dry box. After 
the attachment of a nitrogen bleed THF (20.00 mL) was added followed by 
bis(trimethylsilyl) adipate (2.50 mL). After 60 minutes the polymerization 
was terminated by the addition of water (10 mL), THF (25 mL) and diethyl 
ether (25 mL). The resulting organic phase was washed with water 
(2.times.50 mL) separated, concentrated at reduced pressure and then dried 
under vacuum. Polymer yield: 1.29 g. GPC analysis: Mn=16900, Mw=19400, 
PD=1.15 (PS STD.). 
EXAMPLE 13 
Polymerization of THF with Bis(trimethylsilyl) adipate and Zirconium 
Triflate 
In a dry box, zirconium triflate (1.00 g) was added to a 100 mL round 
bottom flask equipped with a stirring bar. The flask was sealed with a 
rubber septum and removed from the dry box. After the attachment of a 
nitrogen bleed THF (20.00 mL) was added followed by bis(trimethylsilyl) 
adipate (2.50 mL). After 60 minutes the polymerization was terminated by 
the addition of water (10 mL), THF (25 mL) and diethyl ether (25 mL). The 
resulting organic phase was washed with water (2.times.50 mL) separated, 
concentrated at reduced pressure and then dried under vacuum. Polymer 
yield: 9.67 g. GPC analysis: Mn=28100, Mw=45700, PD=1.63 (PS STD.). 
EXAMPLE 14 
Polymerization of THF with Vinylmethyldiacetoxysilane and Yttrium Triflate 
In a dry box, yttrium triflate (1.50 g) was added to a 100 mL round bottom 
flask equipped with a stirring bar. The flask was sealed with a rubber 
septum and removed from the dry box. After the attachment of a nitrogen 
bleed THF (10.00 mL) was added followed by vinylmethyldiacetoxysilane 
(2.50 mL). After 60 minutes the polymerization was terminated by the 
addition of water (10 mL), THF (25 mL) and diethyl ether (25 mL). The 
resulting organic phase was washed with water (2.times.50 mL) separated, 
concentrated at reduced pressure and then dried under vacuum. Polymer 
yield: 3.19 g. GPC analysis: Mn=20600, Mw=29900, PD=1.45 (PS STD.). 
EXAMPLE 15 
Polymerization of THF with Vinylmethyldiacetoxysilane and Erbium Triflate 
In a dry box, erbium triflate (1.50 g) was added to a 100 mL round bottom 
flask equipped with a stirring bar. The flask was sealed with a rubber 
septum and removed from the dry box. After the attachment of a nitrogen 
bleed THF (10.00 mL) was added followed by vinylmethyldiacetoxysilane 
(2.50 mL). After 60 minutes the polymerization was terminated by the 
addition of water (10 mL), THF (25 mL) and diethyl ether (25 mL). The 
resulting organic phase was washed with water (2.times.50 mL) separated, 
concentrated at reduced pressure and then dried under vacuum. Polymer 
yield: 4.65 g. GPC analysis: Mn=25900, Mw=36400, PD=1.40 (PS STD.). 
EXAMPLE 16 
Polymerization of THF with Methyltriacetoxysilane and Erbium Triflate 
In a dry box, erbium triflate (1.50 g) was added to a 100 mL round bottom 
flask equipped with a stirring bar. The flask was sealed with a rubber 
septum and removed from the dry box. After the attachment of a nitrogen 
bleed THF (10.00 mL) was added followed by methyltriacetoxysilane (2.50 
mL). After 60 minutes the polymerization was terminated by the addition of 
water (10 mL), THF (25 mL) and diethyl ether (25 mL). The resulting 
organic phase was washed with water (2.times.50 mL) separated, 
concentrated at reduced pressure and then dried under vacuum. Polymer 
yield: 5.48 g. GPC analysis: Mn=16800, Mw=26100, PD=1.55 (PS STD.). 
EXAMPLE 17 
Polymerization of THF with Tris(trimethylsilyl) Phosphate and Aluminum 
Triflate 
In a dry box, aluminum triflate (1.50 g) was added to a 100 mL round bottom 
flask equipped with a stirring bar. The flask was sealed with a rubber 
septum and removed from the dry box. After the attachment of a nitrogen 
bleed THF (10.00 mL) was added followed by tris (trimethylsilyl) phosphate 
(2.50 mL). After 60 minutes the polymerization was terminated by the 
addition of water (10 mL), THF (25 mL) and diethyl ether (25 mL). The 
resulting organic phase was washed with water (2.times.50 mL) separated, 
concentrated at reduced pressure and then dried under vacuum. Polymer 
yield: 3.11 g. GPC analysis: Mn=31700, Mw=93600, PD=2.95 (PS STD.). 
EXAMPLE 18 
Polymerization of THF with Di-t-butoxydiacetoxysilane and Ytterbium 
Triflate 
In a dry box, ytterbium triflate (1.5 g) was added to a 100 mL round bottom 
flask equipped with a stirring bar. The flask was sealed with a rubber 
septum and removed from the dry box. After the attachment of a nitrogen 
bleed THF (10.00 mL) was added followed by di-t-butoxydiacetoxysilane 
(2.50 mL). After 60 minutes the polymerization was terminated by the 
addition of water (10 mL), THF (25 mL) and diethyl ether (25 mL). The 
resulting organic phase was washed with water (2.times.50 mL) separated, 
concentrated at reduced pressure and then dried under vacuum. Polymer 
yield: 4.31 g. GPC analysis: Mn=6440, Mw=9830, PD=1.53 (PS STD.). 
EXAMPLE 19 
Polymerization of THF with Trimethylsilylisocyanate and Ytterbium Triflate 
In a dry box, ytterbium triflate (1.50 g) was added to a 100 mL round 
bottom flask equipped with a stirring bar. The flask was sealed with a 
rubber septum and removed from the dry box. After the attachment of a 
nitrogen bleed THF (10.00 mL) was added followed by 
trimethylsilylisocyanate (3.50 mL). After 60 minutes the polymerization 
was terminated by the addition of water (10 mL), THF (25 mL) and diethyl 
ether (25 mL). The resulting organic phase was washed with water 
(2.times.50 mL) separated, concentrated at reduced pressure and then dried 
under vacuum. Polymer yield: 0.27 g. GPC analysis: Mn=41600, Mw=50600, 
PD=1.22 (PS STD.). 
EXAMPLE 20 
Polymerization of THF with 1,1,1,3,3,-Pentamethyl-3-acetoxydisiloxane and 
Ytterbium Triflate 
In a dry box, ytterbium triflate (1.50 g) was added to a 100 mL round 
bottom flask equipped with a stirring bar. The flask was sealed with a 
rubber septum and removed from the dry box. After the attachment of a 
nitrogen bleed THF (10.00 mL) was added followed by 
1,1,1,3,3,-pentamethyl-3-acetoxydisiloxane (3.50 mL) . After 60 minutes 
the polymerization was terminated by the addition of water (10 mL), THF 
(25 mL) and diethyl ether (25 mL). The resulting organic phase was washed 
with water (2.times.50 mL) separated, concentrated at reduced pressure and 
then dried under vacuum. Polymer yield: 5.67 g. GPC analysis: Mn=12000, 
Mw=20000, PD=1.65 (PS STD.). 
EXAMPLE 21 
Polymerization of THF with Dimethyldiformoxysilane and Nafion.RTM. 
In a dry box, Nafion.RTM. (5.87 g) was added to a 100 mL round bottom flask 
equipped with a stirring bar. The flask was sealed with a rubber septum 
and removed from the dry box. After the attachment of a nitrogen bleed THF 
(20.00 mL) was added followed by dimethyldiformoxysilane (5.00 mL). After 
120 minutes the polymerization solution was poured from the solid 
catalyst. The solid catalyst was washed with THF (2.times.25 mL). The 
combined organic solution was then concentrated at reduced pressure and 
then dried under vacuum. Polymer yield: 3.89 g. GPC analysis: Mn=5760, 
Mw=10200, PD=1.78 (PS STD.). 
EXAMPLE 22 
Polymerization of THF with 4-(tert-Butyldimethylsiloxy)-3-pentene-2-one and 
Erbium Triflate 
In a dry box, erbium triflate (3.00 g) was added to a 100 mL round bottom 
flask equipped with a stirring bar. The flask was sealed with a rubber 
septum and removed from the dry box. After the attachment of a nitrogen 
bleed THF (20.00 mL) was added followed by 
4-(tert-butyldimethylsiloxy)-3-pentene-2-one (3.00 mL). After 60 minutes 
the polymerization was terminated by the addition of water (10 mL), THF 
(25 mL) and diethyl ether (25 mL). The resulting organic phase was washed 
with water (2.times.50 mL) separated, concentrated at reduced pressure and 
then dried under vacuum. Polymer yield: 2.79 g. GPC analysis: Mn=9570, 
Mw=16000, PD=1.68 (PS STD.). 
EXAMPLE 23 
Polymerization of THF with 1-(Trimethylsiloxy)cyclohexene and Erbium 
Triflate 
In a dry box, erbium triflate (3.00 g) was added to a 100 mL round bottom 
flask equipped with a stirring bar.. The flask was sealed with a rubber 
septum and removed from the dry box. After the attachment of a nitrogen 
bleed THF (20.00 mL) was added followed by 1-(trimethylsiloxy) cyclohexene 
(3.00 mL) . After 60 minutes the polymerization was terminated by the 
addition of water (10 mL), THF (25 mL) and diethyl ether (25 mL). The 
resulting organic phase was washed with water (2.times.50 mL) separated, 
concentrated at reduced pressure and then dried under vacuum. Polymer 
yield: 0.43 g. GPC analysis: Mn=38700, Mw=53300, PD=1.38 (PS STD.). 
EXAMPLE 24 
Polymerization of THF with Tetramethoxysilane and Erbium Triflate 
In a dry box, erbium triflate (3.00 g) was added to a 100 mL round bottom 
flask equipped with a stirring bar. The flask was sealed with a rubber 
septum and removed from the dry box. After the attachment of a nitrogen 
bleed THF (20.00 mL) was added followed by tetramethoxysilane (3.00 mL). 
After 60 minutes the polymerization was terminated by the addition of 
water (10 mL), THF (25 mL) and diethyl ether (25 mL). The resulting 
organic phase was washed with water (2.times.50 mL) separated, 
concentrated at reduced pressure and then dried under vacuum. Polymer 
yield: 0.43 g. GPC analysis: Mn=5670, Mw=8100, PD=1.43 (PS STD.). 
EXAMPLE 25 
Polymerization of THF with tert-Butyldimethylchlorosilane and Ytterbium 
Triflate 
In a dry box, ytterbium triflate (3.00 g) and 
tert-butyldimethylchlorosilane (3.00 g) were added to a 100 mL round 
bottom flask equipped with a stirring bar. The flask was sealed with a 
rubber septum and removed from the dry box. After the attachment of a 
nitrogen bleed THF (20.00 mL) was added. After 180 minutes the 
polymerization was terminated by the addition of water (10 mL), THF (25 
mL) and diethyl ether (25 mL). The resulting organic phase was washed with 
water (2.times.50 mL) separated, concentrated at reduced pressure and then 
dried under vacuum. Polymer yield: 4.8 g. 
EXAMPLE 26 
Polymerization of THF with Dimethyldichlorosilane and Ytterbium Triflate 
In a dry box, ytterbium triflate (3.00 g) was added to a 100 mL round 
bottom flask equipped with a stirring bar. The flask was sealed with a 
rubber septum and removed from the dry box. After the attachment of a 
nitrogen bleed THF (20.00 mL) and dimethyldichlorosilane (3.00 g) were 
added. After 60 minutes the polymerization was terminated by the addition 
of water (10 mL), THF (25 mL) and diethyl ether (25 mL). The resulting 
organic phase was washed with water (2.times.50 mL) separated, 
concentrated at reduced pressure and then dried under vacuum. Polymer 
yield: 11.98 g. 
EXAMPLE 27 
Polymerization of THF with p-Trimethylsiloxynitrobenzene and Ytterbium 
Triflate 
In a dry box, ytterbium triflate (3.00 g) was added to a 100 mL round 
bottom flask equipped with a stirring bar. The flask was sealed with a 
rubber septum and removed from the dry box. After the attachment of a 
nitrogen bleed THF (20.00 mL) and p-trimethylsiloxynitrobenzene (3.00 g) 
were added. After 60 minutes the polymerization was terminated by the 
addition of water (10 mL), THF (25 mL) and diethyl ether (25 mL). The 
resulting organic phase was washed with water (2.times.50 mL) separated, 
concentrated at reduced pressure and then dried under vacuum. Polymer 
yield: 3.06 g. 
EXAMPLE 28 
Polymerization of THF with Bromotrimethylsilylacetate and Ytterbium 
Triflate 
In a dry box, ytterbium triflate (3.00 g) was added to a 100 mL round 
bottom flask equipped with a stirring bar. The flask was sealed with a 
rubber septum and removed from the dry box. After the attachment of a 
nitrogen bleed THF (20.00 mL) and bromotrimethylsilylacetate (3.00 g) were 
added. After 60 minutes the polymerization was terminated by the addition 
of water (10 mL), THF (25 mL) and diethyl ether (25 mL). The resulting 
organic phase was washed with water (2.times.50 mL) separated, 
concentrated at reduced pressure and then dried under vacuum. Polymer 
yield: 12.90 g.