Process for the preparation of water-soluble...

Details Process for the preparation of water-soluble... Process for the preparation of water-soluble...

2001-01-23

2003-10-21

Lipman, Bernard (Department: 1713)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Polymers from only ethylenic monomers or processes of...

Reexamination Certificate

active

06635729

ABSTRACT:

BACKGROUND OF THE INVENTION
The invention relates to the preparation of water-soluble &pgr;-conjugated polymers by chemical polymerization in water.
The &pgr;-conjugated polymer class of compounds has been the subject matter of numerous publications in recent decades. They are also known as conductive polymers or synthetic metals.
Due to the considerable delocalization of the &pgr;-electrons along the main chain, these polymers exhibit interesting (nonlinear) optical properties and, after oxidation or reduction, are good electronic conductors. These compounds will therefore probably take on a leading and active role in various practical areas of application, such as, for example, in data storage, optical signal processing, suppression of electromagnetic interference and the conversion of solar energy, and in rechargeable batteries, light-emitting diodes, field-effect transistors, circuit boards, sensors and antistatic materials.
Examples of known &pgr;-conjugated polymers are polypyrroles, polythiophenes, polyanilines, polyacetylenes, polyphenylenes, and poly(p-phenylenevinylenes). They can be prepared by various chemical and electrochemical polymerization methods. For the industrial preparation of these &pgr;-conjugated polymers, chemical polymerization of the monomeric compounds is the most favorable process.
The development of &pgr;-conjugated polymers has been hindered for some time due to problems in their processing. Some of these problems have been solved by the introduction of the first soluble conjugated polymers, namely poly(3-alkylthiophenes). It was possible to process the latter in organic solvents and thus apply them to supports by spin coating. Due to increasing environmental consciousness, industry has concentrated on the development of water-soluble conjugated polymers. Again, polythiophenes functionalized with sulfonate groups were developed initially. Due to the sulfonate groups, these polythiophenes were more readily soluble in aqueous solutions and the use of undesired solvents, such as chloroform and acetonitrile, was avoided. The first water-soluble polythiophenes were quickly followed by other conjugated polymers, such as, for example, polypyrroles, polyanilines, polyphenylenes and poly(phenylenevinylenes).
One of the most successful and environmentally friendly &pgr;-conjugated polymers is poly(3,4-ethylenedioxythiophene) (“PEDT”). See EP-A 339,340. It has been converted into a processable aqueous dispersion by mixing with polystyrene sulfonic acid (“PSS”). See EP-A 440,957. The resultant mixture has excellent film-forming properties and combines high conductivity with high transparency.
Recently Chevrot et al. (
J. Electroanal. Chem.,
1998, 443, 217-226, and
J. CHIM. PHYS,
1998, 95, 1168-1171), published the synthesis of a novel 3,4-ethylenedioxythiophene derivative, 4-(2,3-dihydrothieno[3,4-b][1,4]dioxin-2-ylmethoxy)-1-butanesulfonic acid sodium salt (“EDT-S”). In spite of a number of attempts to polymerize this monomer in aqueous solution by electrochemical means, all attempts by Chevrot et al. to obtain a water-soluble homopolymer failed due to the high solubility of the resultant oligomer/polymer in water. Instead, the authors succeeded in preparing a 1:1 copolymer of EDT-S and 3,4-ethylenedioxythiophene. However, the derivative was insoluble in water.
Further thiophene derivatives which are likewise soluble in water are described in EP-A 628,560.
During a search for environmentally friendly materials having similar or improved electrical and/or optical properties compared with PEDT/PSS, the novel water-soluble &pgr;-conjugated polymers have been successfully prepared without using PSS.
SUMMARY OF THE INVENTION
The invention therefore relates to a process for the preparation of water-soluble &pgr;-conjugated polymers comprising polymerizing, in aqueous solution using an oxidant, monomeric thiophene derivatives of formula (I)
wherein
X and Y are identical or different and are O, S, or N—R
1
,
Z is —(CH
2
)
m
—CR
2
R
3
—(CH
2
)
n
—,
R
1
is aryl, C
1
-C
18
-alkyl, or hydrogen,
R
2
is hydrogen or —(CH
2
)
s
—O—(CH
2
)
p
—SO
3
−
M
+
,
R
3
is —(CH
2
)
s
—O—(CH
2
)
p
—SO
3
−
M
+
,
M
+
is a cation,
m and n are identical or different and are an integer from 0 to 3,
s is an integer from 0 to 10, and
p is an integer from 1 to 1.
Examples of suitable cations M
+
are H
+
, Li
+
, Na
+
, K
+
, Rb
+
, Cs
+
, and NH
4
+
. Particularly suitable cations are Na
+
and K
+
.
DETAILED DESCRIPTION OF THE INVENTION
Preferred monomers in the process according to the invention are thiophene derivatives of the formula (I) in which
X and Y are O,
Z is —(CH
2
)
m
—CR
2
R
3
—(CH
2
)
n
—,
R
2
is hydrogen or —(CH
2
)
s
—O—(CH
2
)
p
—SO
3
−
M
+
,
R
3
is —(CH
2
)
s
—O—(CH
2
)
p
—SO
3
−
M
+
,
M
+
is a cation,
m and n are identical or different and are an integer from 0 to 3,
s is an integer from 0 to 10, and
p is an integer from 1 to 18.
Particularly preferred monomers in the process according to the invention are thiophene derivatives of the formula (I) in which
X and Y are O,
Z is —(CH
2
)—CR
2
R
3
—(CH
2
)
n
—,
R
2
is hydrogen,
R
3
is —(CH
2
)
s
—O—(CH
2
)
p
—SO
3
−
M
+
,
M
+
is Na
+
or K
+
,
n is 0 or 1,
s is 0 or 1, and
p is 4 or 5.
The monomeric compounds are known and their preparation is described in Chevrot et al.,
J. Electroanal. Chem.,
1998, 443, 217-226, Leclerc et al.,
Adv. Mater.,
1997, 9, 1087-1094 and Reynolds et al.,
Polymer Preprints,
1997, 38 (2), 320.
The polymerization of the monomeric compounds is carried out in water using suitable oxidants. Examples of suitable oxidants are iron(III) salts, particularly FeCl
3
and iron(III) salts of aromatic and aliphatic sulfonic acids, H
2
O
2
, K
2
Cr
2
O
7
, K
2
S
2
O
8
, Na
2
S
2
O
8
, KMnO
4
, alkali metal perborates, and alkali metal or ammonium persulfates, or mixtures of these oxidants. Further suitable oxidants are described, for example, in
Handbook of Conducting Polymers
(Ed. Skotheim, T. A.), Marcel Dekker: New York, 1986, Vol. 1, pages 46-57. Particularly preferred oxidants are FeCl
3
, Na
2
S
2
O
8
, and K
2
S
2
O
8
, or mixtures thereof.
The process according to the invention is preferably carried out at a reaction temperature of from −20 to 100° C. Particular preference is given to reaction temperatures of from 20 to 100° C.
Further water-miscible solvents can also be added to the aqueous reaction mixture. Examples of suitable solvents are aliphatic alcohols, such as methanol, ethanol, isopropanol, and butanol, diacetone alcohols, ethylene glycol, and glycerol. Likewise suitable are aliphatic ketones, such as acetone and methyl ethyl ketone, and aliphatic nitrites, such as acetonitrile.
The resultant polythiophenes are very readily soluble in water.
Since the compounds were hitherto unknown, the invention furthermore relates to the polythiophenes of the formula (II)
wherein
X and Y are identical or different and are O, S, or N—R
1
,
Z is —(CH
2
)
m
—CR
2
R
3
—(CH
2
)
n
—,
R
1
is aryl, C
1
-C
18
-alkyl, or hydrogen,
R
2
is hydrogen or —(CH
2
)
s
—O—(CH
2
)
p
—SO
3
−
M
+
,
R
3
is —(CH
2
)
s
—O—(CH
2
)
p
—SO
3
−
M
+
,
M
+
is a cation,
m and n are identical or different and are an integer from 0 to 3,
s is an integer from 0 to 10,
p is an integer from 1 to 18, and
q is an integer from 2 to 10,000.
Preferred polymers are polythiophenes of the formula (II) in which X and Y are O and Z, R
2
, R
3
, M
+
, m, n, s, p, and q are as defined above.
Particularly preferred polymers are polythiophenes of the formula (II) in which
X and Y are O,
Z is —(CH
2
)—CR
2
R
3
—(CH
2
)
n
—,
R
2
is hydrogen,
R
3
is —(CH
2
)
s
—O—(CH
2
)
p
—SO
3
−
M
+
,
M
+
is Na
+
or K
+
,
n is 0 or 1,
s is 0 or 1,
p is 4 or 5, and
q is an integer from 3 to 1,000.
The polythiophenes of the formula (II) are in cationic form. The positive charges are not shown in the formula since the charges are delocalize

Affiliated with

Also associated with

Rating

Process for the preparation of water-soluble... does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Process for the preparation of water-soluble..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for the preparation of water-soluble... will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3138618