PREPARATION OF ELECTRICALLY CONDUCTIVE POLYAROMATICS AND THEIR USE IN ELECTRICAL ENGINEERING AND FOR THE ANTISTATIC TREATMENT OF PLASTICS

PRODUCTION DE MATERIAUX POLYAROMATIQUES CONDUCTEURS D'ELECTRICITE POUR L'ELECTROTECHNIQUE ET LE TRAITEMENT DES PLASTIQUES POUR LES RENDRE ANTISTATIQUES

English Abstract

ABSTRACT OF THE DISCLOSURE:
The invention relates to a process for the prepara-
tion of an electrically conductive polyaromatic having an
electrical conductivity greater than 10-2 Siemens/cm, said
polyaromatic having the formula
<IMG>
where X is -?r-, Ar is an aromatic system, R is H or an alipha-
tic, cycloaliphatic or aromatic group or a functional group,
and n is an integer from 1 to 50 said process consisting
essentially of treating said polyaromatic in the absence of
moisture with 0.5 to 15% by weight, based on the polyaromatic,
of an oxidizing Lewis-acid.

Claims

The embodiments of the invention in which an exclusive
property or privilege is claimed are defined as follows:
1. A process for the preparation of an electrically
conductive polyaromatic having an electrical conductivity greater
than 10-2 Siemens/cm, said polyaromatic having the formula
<IMG>
where X is -?r-, Ar is an aromatic system, R is H or an alipha-
tie, cycloaliphatic or aromatic group or a functional group, and
n is an integer from 1 to 50 said process consisting essential-
ly of treating said polyaromatic in the absence of moisture with
0.5 to 15% by weight, based on the polyaromatic, of an oxidizing
Lewis acid.
2. The process of claim 1, wherein Ar is phenylene.
3. The process of claim 1, wherein R is H.
4. The process of claim 1 or 3, wherein X is
phenylene.
5. The process of claim 1, wherein the Lewis acid
is selected from the group consisting of SbF5, AsF5 and the
nitro salts thereof.
6. The process of claim 1, wherein the Lewis acid
is a nitroaromatic.
7. The process of claim 6, wherein the nitroaroma-
tic is trinitrophenol or trinitrobenzenesulfonic acid.
8. The process of claim 1, wherein the Lewis acid
-7-

is CF3-COOH.
9. The process of claim 1, wherein the Lewis acid
is selected from the group consisting of sulfuric acid, nitric
acid and perchloric acid.
- 8-

Description

The present in~ention re~ates to a process for the
preparation of electrically conductive polyaxomatics havïng
conductivities greater than 10 Slcm~
The preparation of polyaromatic by oxidative coupling
has been disclosed, for example in ~acromolecular Syntheses
Collective (published by John Wiley and Sons), 1 (1979~, 109-
110, and Naturwissenschaften, 56 (1969), 308-313. Furthermore,
polyaromatics may be prepared by stepwise polycondensation as
described by R. Gehm and W. Kern, Makromol. Chem. 7 (1951),
46-61, this method giving particularly uniform methyl-substi-
tuted derivatives, with para-chain linkages, free from conta-
mination by ortho- or meta-linked polymers. The polyaromatics
may also be prepared as described by P.R. Schildneck et al.,
J. Amer. Chem. Soc. 53 (1931), 2373.
It is an object of the present invention to provide
a process for the preparation of an electrically conductive
polyaromatic having an electrical conduc-tivity greater than
10 2 Siemens/cm, said polyaromatic having the ~ormula
br ~
OH n
R
where X is -~r-, Ar is an aromatic system, R is H or an alipha-
tic, cycloaliphatic or aromatic group or a functional group, and
n is an integer from 1 to 50 said process consisting essential-
ly of treating said polyaromatic in the absence of moisture with
0.5 to 15~ by weight, based on the polyaromatic, of an oxidizing
Lewis acid.
We have found that this object is achieved, according
to the invention, by adcling to the polyaromatic, in the absence
of moistur~, from 0.5 to 15~ by weight, based on polyaromatic
'6,~

employed, of an oxidizing Lewis acid., eg. an.timony pen.tafluo-
ride or arsenic pentafluoride, or their ~:0*.- or ~C2 -.salts,
or a nitroaromatic, eg~ trinitrophenol or trinïtro- _
/ !
/ i
-- _ .
~ - la -

~ 2 - o.Z. 0050/034220
benzenesulfonic acid, and/or a fluorine derivative, eg
C~3-COOH, or an acid, eg. sulfuric acid9 nitric acid or
perchloric acid. In a preferred embodiment, -the
oxidizing Lewis acids are added in tetrahydrofuran,
dimethoxyglycol, anthracene, naphthalene or 2-methyl-
styrene, in each case in a molar ratio of from 1:1 to
1:50, preferably from 1:2 to 1:3
For the purposes of the invention, polyaromatics
are the conventional relatively high molecular weight
products whose chains consist entirely of aromatic
systems which are coupled to one another and may or may
not carry substituents R, in accordance with the general
~ormula:
E Ar
OH n
and which are obtained from benzene or substituted ben-
zenes, and benzoquinone or derivatlves thereof, by a
Friedel-Crafts reaction under dehydrogenating conditions,
or by other dehydrogenating or oxidative coupling pro-
cesses, followed by reduction, Polyaromatics in which
the linkage of the aromatic systems is linear are pre-
ferred. The polyaromatics have molecular weights o~
from 200 to 5,000, ie n is ~rom 1 to 50. The pre-
paration o~ the polyaromatics may be carried out in
accordance with the litera-ture quoted a-t the outset.
In the above formula, X is ~r -R, ~r is an aromatic sys-
tem, preferably phenylene, and R is H or an aliphatic,
cycloaliphatic or aromatic group, or a functional group~

2~
_ 3 _ o.z. 0050/034220
R
for example CN or N/
The electrical conductivities are measured at
~0C by the method of F. Beck, Ber. Bunsengesellschaft,
Phys. Chem. 68 (1964), 558-567, and are recorded in S/cm.
The novel conductive polyaromatics have conductivities
greater than 10 2 S/cm,
In the process according to the invention, from
0.5 to 15% by weight, based on polyaromatic employed, of
an oxidizing Lewis acid, eg. antimony penta~luoride or
arsenic pentafluoride, or their N0+- or N02+-salts, or a
nitroaromatic, eg, trinitro-
phenol or trinitrobenzenesulfonic acid, and/or a
fluorine derivative, eg, CF3-COOH, or an acid, eg.
sulfuric acid, nitric acid or perchloric acid~ is added
to the pol~aromatic, in the absence of moisture.
The additives are incorporated in the
ab ence of moi~ture, preferably under an argon atmos-
phere, It is preferred to use an auxiliary fluid,
such as tetrah~drofuran, nitromethane, CC14 or CHC13, in
each case in a molar ratio of from 1:1 to 1:50, prefer-
ably from 102 to 1:3; after the additive has been incor-
porated, the fluid is stripped off under reduced pressure
at below ~0C,
Increases in electrical conductivity of several
orders of magnitude can be achieved by the stated addi-
tives, The initial conductivity of the polyaromatics
prepared by oxidative coupling is from about 10 12 to
10 8 S/cm. The polyaromatics prepared by

1~6~2~4
_ 4 _ o.z. ooso/03~220
condensation have initial conductivities of less than
10 12 S/cm, but after a~di-tîon of the additives according
to the invention give conductivities of not less than
10- S/cm.
The electrically conductive polyaromatics prepared
according to the invention and having conductivities of
not less than 10 2 S/cm may be used for the antistatic
treatment of plastics, for the production of solar cells,
for the conversion and fixing of radiation and for the
production of electrical and magnetic switches. The
addition of the strong Lewis acid to the polyaromatic
results in the formation of a p-conductor.
In the Examples which follow, parts are by weight.
The number of repeat units n (which indicates the chain
length o~ the polyaroma-tics) is obtained by end group
analysis, through infrared determinatiorl of the ratio of
monofunctional terminal groups to difunctional non-
terminal groups.
EXAMPLES 1 T0 8
The type and amount o~ additive shown is added
to 10 parts of a polyaromatic under an argon atmosphere,
with exclusion of moisture. The elec-trical conduc-
tivity is measured by the method of F. Beck, loc. cit.
. . .i

- 5 - 0. Z. 0050/034220
.
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ll
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E3~ h h h h h h h h
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Notes on Table
l) Polyaromatic prepared by the method of R. Gehm et al.,
loc. cit.
2) Prepared by the method of (2a) P.R. S~hi~.d~eck.e-~ al, J.
AmerO Chem. Soc. 53 (1931)9 2373, followed by oxidative
coupling as described in Macromolecular Syntheses
Collective J l (1979 ), lO9-llo
R
In Examples 1 to 8, X = - Ar ~J R
In Examples 1 to 5 and 8, - Ar =
R
In Example 6, -Ar- =
In Example 7, -Ar- is
.~