Production of aromatic polysulphones

Aromatic polysulphones are prepared by the reaction under substantially anhydrous conditions in the presence of a fluoroalkane sulphonic acid, particularly trifluoromethane sulphonic acid or difluoromethane sulphonic acid, of the reactants selected from the following class: PA1 (a) an aromatic compound of specified formula (such as diphenyl ether or diphenyl) and a sulphonating agent; PA1 (b) an aryl monosulphonic acid of specified formula (such as diphenyl ether-4-sulphonic acid or diphenyl-4-sulphonic acid); and PA1 (c) an aryl disulphonic acid of specified formula (such as diphenyl ether-4,4'-disulphonic acid or diphenyl-4,4'-disulphonic acid) and an aromatic compound as defined in (a).

The present invention relates to a process for the production of aromatic 
polysulphones. 
Thermoplastic aromatic polysulphones are polymers which are well known to 
the art. They are of significant commercial utility in view of their 
excellent mechanical performance at high temperatures, their high strength 
and toughness and their excellent resistance to fire and chemicals. 
Heretofore, two quite distinct synthetic methods have usually been employed 
for the production of aromatic polysulphones. 
The first of these methods involves a polysulphonylation process in which 
sulphone linkages are formed by the polymerisation reaction between an 
aryl disulphonyl halide with a compound containing at least two 
aromatically bound hydrogen atoms or by the self-polymerisation of an aryl 
monosulphonyl halide containing at least one aromatically bound hydrogen 
atom. Such a process involves electrophilic aromatic substitution in which 
the aromatic substrate is attacked by some form of an aryl sulphonylium 
cation and hydrogen displaced as a proton. The attacking agent is formed 
by the interaction of the sulphonyl halide with an anhydrous Lewis acid, 
also known as a Friedel-Crafts catalyst. Examples of this type of process 
are described in British Pat. Nos. 1 016 245, 1 109 842 and 1 060 546. 
The second of these methods involves a nucleophilic polyetherification 
process where a dialkali metal salt of a dihydric phenol is reacted with 
an activated dihalobenzenoid compound, or a monoalkali metal salt of an 
activated halophenol is self-reacted, to provide ether bonds via 
displacement of halogen by phenoxide anions with the removal of halogen as 
alkali metal halide. The halogen atoms of the dihalobenzenoid compound or 
halophenol are activated to nucleophilic attack by a sulphone substituent 
group situated ortho or para therto, so that an aromatic polyethersulphone 
polymer is formed. Examples of this type of process are described in 
British Pat. Nos. 1 078 234 and 1 153 035. 
Both the nucleophilic and electrophilic processes described above require 
the utilisation of monomeric starting materials which can sometimes be 
difficult or expensive to obtain commercially. Thus the electrophilic 
process employs a mono- or disulphonyl halide while the nucleophilic 
process requires the use of dihydric phenol and dihalobenzenoid compound 
or halophenol. 
I have now discovered a very versatile and useful electrophilic process for 
the production of aromatic polysulphones which does not require the 
provision of an aryl sulphonyl halide for the polymerisation reaction. 
According to the present invention there is provideda process for the 
production of an aromatic polysulphone which comprises reacting under 
substantially anhydrous conditions in the presence of a fluoroalkane 
sulphonic acid the reactants selected from the following class: 
(a) at least one aromatic compound of formula 
##STR1## 
wherein --Y-- is a direct link, --O--, 
##STR2## 
--CF.sub.2 --, --CR.sub.1 R.sub.2 -- where R.sub.1 and R.sub.2 which may 
be the same or different are fully fluorinated alkyl radicals, or 
##STR3## 
where --X-- and --X'-- which may be the same or different are each a 
direct link, --O--, --CF.sub.2 --, or --CR.sub.1 R.sub.2 -- where R.sub.1 
and R.sub.2 are as defined above, and --Z-- is --CO--, --SO.sub.2 --, 
--CF.sub.2 --, or --CR.sub.1 R.sub.2 -- where R.sub.1 and R.sub.2 are as 
defined above; or a nuclear substituted derivative thereof provided that 
at least the nuclear hydrogen atoms para to --Y-- remain unsubstituted; 
and a sulphonating agent; 
(b) at least one aryl monosulphonic acid of formula 
##STR4## 
wherein --Y-- is as defined in (a); or a nuclear-substituted derivative 
thereof provided that in the benzene ring linked to --Y-- not having the 
sulphonic acid group at least the nuclear hydrogen atom para to --Y-- 
remains unsubstituted; 
(c) at least one aryl disulphonic acid of formula 
##STR5## 
wherein --Y-- is as defined in (a); or a nuclear-substituted derivative 
thereof; 
and at least one aromatic compound as defined in (a). 
It is to be understood that the aryl monosulphonic and aryl disulphonic 
acids used in (b) and (c) may if desired be generated by starting from the 
corresponding alkali metal salts and generating the acids by admixture 
with the acidic medium. 
Thus the process of the invention does not employ an aryl sulphonyl halide 
(as previously commonly employed when preparing a thermoplastic aromatic 
polysulphone using an electrophilic process) but, instead, an aromatic 
compound and a sulphonating agent as defined in (a), or an aryl 
monosulphonic acid as defined in (b), or an aryl disulphonic acid and an 
aromatic compound as defined in (c). The ability of an aromatic compound 
and a sulphonating agent as defined in (a), or an aryl monosulphonic acid 
as defined in (b), or an aryl disulphonic acid and an aromatic compound as 
defined in (c) to undergo electrophilic polymerisation in the presence of 
a fluoroalkane sulphonic acid to a thermoplastic aromatic polysulphone was 
hitherto unsuspected. Moreover the aromatic substances used in the process 
of the invention are generally speaking cheaper and more readily available 
than aryl sulphonyl halides. 
The presence of the fluoroalkane sulphonic acid in the process of the 
invention is a crucial feature, and it is thought that this reagent acts 
as a Lewis Acid and, at least to a certain extent, as a dehydrating agent. 
The preferred fluoroalkane sulphonic acids for use according to the 
invention are trifluoromethane sulphonic acid CF.sub.3 SO.sub.2 OH and 
difluoromethane sulphonic acid CF.sub.2 HSO.sub.2 OH. Other fluoroalkane 
sulphonic acids which may be used are the higher members of a series of 
fluoroalkane sulphonic acids containing 1 to 18 carbon atoms (which may be 
fully fluorinated as described in GB 758 467 or partially fluorinated), 
e.g. the fluoroethane and fluoropropropane sulphonic acids such as 
CF.sub.3 CF.sub.2 SO.sub.2 OH, CF.sub.2 HCF.sub.2 SO.sub.2 OH and CF.sub.3 
CF.sub.2 CF.sub.2 SO.sub.2 OH and the polymeric fluoroalkane sulphonic 
acids such as the `Nafion` products. It is convenient to adjust the amount 
of fluoroalkane sulphonic acid used so that the acid, if liquid, acts as 
the reaction solvent. The use of a reaction system which comprises a more 
catalytic (i.e. much smaller) quantity of the fluoroalkane sulphonic acid 
is not, however, excluded from the scope of the invention. 
By reaction under substantially anhydrous conditions is meant ensuring that 
free moisture is substantially excluded from the reaction mixture both 
before and during the reaction. Of course, water is produced as the 
reaction proceeds but it is thought that this is substantially removed by 
the fluoroalkane sulphonic acid and (if employed) by an added dehydrating 
agent. 
In the reactant sub-class (a) of the invention, the use of which is 
preferred to that of sub-classes (b) or (c), a single aromatic compound 
(as defined) may be used in the preparation of the aromatic polysulphone 
to produce a polymer consisting solely of units derived from this 
compound; alternatively two or more such aromatic compounds may be 
employed to produce a copolymer consisting of units derived from these 
compounds. It is preferable that substantially equimolar quantities of the 
at least one aromatic compound and the sulphonating agent be employed. 
Generally speaking, to effect the process of the invention using reactant 
sub-class (a) it is convenient to dissolve the aromatic compound in the 
fluoroalkane sulphonic acid and then to add the sulphonating agent 
(possibly dissolved in fluoroalkane sulphonic acid) followed by a period 
of reaction at the selected reaction temperature(s). 
The sulphonating agent which is employed in reactant sub-class (a) of the 
present invention should be one that has been found by experiment to be 
effective. I have already found, for example, that sulphuric acid and 
chlorosulphonic acid are sulphonating agents which will yield an aromatic 
polysulphone according to the process of the invention. 
In the reactant sub-class (b) of the invention, a single aryl monosulphonic 
acid (as defined) may be used in the preparation of the aromatic 
polysulphone to produce a polymer consisting solely of units derived from 
this compound; alternatively two or more such aryl monosulphonic acids may 
be employed to produce a copolymer consisting of units derived from these 
compounds. 
In the reactant sub-class (c) of the invention a single aryl disulphonic 
acid (as defined) and a single aromatic compound (as defined) may be used 
in the preparation of the aromatic polysulphone to produce a polymer 
consisting solely of units derived from these compounds; alternatively two 
or more such aryl disulphonic acids and/or two or more such aromatic 
compounds may be employed to produce a copolymer containing units derived 
from these compounds. It is preferable to employ substantially equimolar 
quantities of the at least one aryl disulphonic acid and the at least one 
aromatic compound. However the proportions may be varied slightly from 
equimolar quantities in order to modify the molecular weight of the 
product. 
The aromatic substances (as defined) which are used in the process of the 
present invention are preferably unsubstituted in the aromatic nuclei 
(i.e. apart from the substituents which are present as indicated in the 
formulae (i), (ii) and (iii)); nuclear substitution tends to affect the 
activity of the aromatic substances in the polymerisation reaction. 
Nevertheless, nuclear-substituted aromatic substances may be employed in 
the present invention (with the provisions, as defined, concerning 
hydrogen atoms) providing that the substituent or substituents do not 
deleteriously affect the polymerisation reaction or the properties of the 
polymer so produced. Whether or not the position and nature of a nuclear 
substituent has a deleterious effect may be discovered by experimentation. 
It is a surprising feature of the present invention that in most cases the 
polymerisation reaction can be carried out or controlled to yield a 
predominantly "all para" product, i.e. a product in which most of the 
sulphonylated benzene rings of the repeat units are parasulphonylated with 
respect to Y because the chain extension by the sulphonylating species has 
proceeded predominantly through substitution of the hydrogen atom(s) para 
to the group Y. (The achievement of a wholly or predominantly all para 
aromatic polysulphone is highly desirable because the mechanical 
properties of aromatic polysulphones increasingly deteriorate as the 
proportion of ortho-sulphonylated benzene rings in the polymer becomes 
greater.) 
Thus, e.g., in the case of employing an aromatic compound in reactant 
sub-class (a) of formula 
##STR6## 
the polymerisation may be controlled in most cases to yield a polymer 
consisting almost entirely of para-sulphonylated repeat units of formula 
##STR7## 
Since groups such as aryl, aralkyl, and aryl ether are usually ortho/para 
orientating, a polymer containing a significant proportion of 
ortho-sulphonylated repeat units of formula 
##STR8## 
might be expected to be usually produced. However, the proportion of such 
ortho-sulphonylated repeat units in the polymer produced can be controlled 
by manipulating the conditions of the polymerisation, so that polymers 
having predominantly all para-sulphonylated repeat units are formed. 
Similarly, in the case of using reactant sub-class (b), when the aromatic 
monosulphonic acid employed has the formula 
##STR9## 
the aromatic polysulphone produced in many cases is likely to consist 
almost entirely of all para repeat units of formula 
##STR10## 
Similarly, when using reactant sub-class (c), when employing an aromatic 
compound of formula 
##STR11## 
and an aryl disulphonic acid of formula 
##STR12## 
the aromatic polysulphone produced in many cases is likely to consist 
almost entirely of all para repeat units of formula 
##STR13## 
which reduces to 
##STR14## 
Our experience thus far indicates that control of the proportion 
ortho-sulphonylation may be achieved, for example, according to the 
reaction temperature employed; generally speaking, a higher polymerisation 
temperature favours a lower ortho content and a higher all para content; 
this is fortuitous in that a higher polymerisation temperature also 
favours a faster reaction rate. 
In some of the Examples of this specification, an estimate of the 
proportion of ortho-sulphonylation in the aromatic polysulphone produced 
is provided by the use of nuclear magnetic resonance (nmr) spectroscopy 
(220 MHz) by virtue of the fact that the nmr signal due to the aromatic 
hydrogen atoms in the para-sulphonylated benzene rings can be readily 
distinguished from the signal due to the aromatic hydrogen atoms in the 
ortho-sulphonylated benzene rings. This proportion is termed the 
percentage of ortho-sulphonylation and is defined by: 
##EQU1## 
where o is the number of benzene rings in which Y and SO.sub.2 are ortho 
to each other and p is the number of benzene rings in which Y and SO.sub.2 
are para to each other. 
It is interesting to note that the process of the invention does not appear 
to be applicable to polymerisations which would involve the sulphonylation 
of condensed aromatic ring systems or extended polyphenylene systems. 
Thus, e.g., in the case of reactant sub-class (a), the use of aromatic 
compounds such as naphthalene, anthracene, phenanthrene, quinoline, 
isoquinoline, and terphenyl results either in the formation of 
unhandleable substances (tars etc) or in the formation of no product at 
all. 
It is sometimes useful to effect the process of the present invention in 
the presence of a dehydrating agent (the term "dehydrating agent" as used 
here is not intended to embrace the fluoroalkane sulphonic acid, the 
presence of which is an essential requirement of the invention). This is 
particularly the case when employing reactant subclass (a) of the 
invention with conc. sulphuric acid as the sulphonating agent, since the 
aromatic polysulphone so formed tends to be of low molecular weight, 
having a reduced viscosity (RV) of &lt;0.25. (Reduced viscosity (RV) as used 
herein normally refers to the measurement of viscosity at 25.degree. C. on 
a solution of the polymer in dimethyl formamide containing 1 g of polymer 
in 100 cm.sup.3 of solution. In rare cases, however, the aromatic 
polysulphone is insoluble in dimethyl formamide, and RV then refers to the 
measurement of viscosity at 25.degree. C. on a solution of the polymer in 
trifluoromethane sulphonic acid containing 1 g of polymer in 100 cm.sup.-3 
of solution.) These low molecular weight aromatic polysulphones are of 
utility, e.g. as a component of aqueous coating dispersions containing 
tetrafluoroethylene polymers from which well-adhered continuous coatings 
on various substrates may be prepared--as described in British Pat. No. 1 
527 851. However, generally speaking, aromatic polysulphones of reduced 
viscosity of at least 0.3, particularly at least 0.35, are more useful 
since these have a combination of physical properties (such as tensile 
strength, modulus and softening point) which make them particularly 
suitable as materials for mouldings, extrusions and films. It is found 
that the incorporation of an effective dehydrating agent into the reaction 
mixture which employs reactant sub-class (a), e.g. when using conc. 
sulphuric acid as the sulphonating agent, results in the formation of an 
aromatic polysulphone having RV of at least 0.3, and particularly at least 
0.35. It is not, however, always necessary to employ a dehydrating agent 
to ensure that the aromatic polysulphone produced is of high molecular 
weight; thus, e.g., where chlorosulphonic acid is used as the sulphonating 
agent in reactant sub-class (a) the aromatic polysulphone produced is 
often of RV at least 0.30 whether a dehydrating agent is employed or not. 
The dehydrating agent (if used) should be one which does not cause the 
resulting aromatic polysulphone to undergo unacceptable degradation or 
cleavage or other deleterious side reactions and should preferably, in 
conjunction with the other reagents, result in the formation of an 
aromatic polysulphone of reduced viscosity at least 0.3. Whether or not a 
dehydrating agent is effective may in some circumstances depend on the 
amount which is used. A preferred dehydrating agent to employ is 
phosphorus pentoxide (P.sub.2 O.sub.5). 
Generally speaking, to effect the process of the invention using reactant 
sub-class (a) when using dehydrating agent it is convenient to dissolve 
the aromatic compound in fluoroalkane sulphonic acid and then to add the 
sulphonating agent (possibly dissolved in fluoroalkane sulphonic acid) and 
the dehydrating agent followed by a period of reaction at the selected 
reaction temperature(s). It may be helpful to add some of the dehydrating 
agent used during the course of the reaction. 
It is, of course, also possible to employ a dehydrating agent when using 
reactant sub-classes (b) and (c) of the invention, particularly if an 
aromatic polysulphone of improved RV is obtained. 
In the formulae (i), (ii) and (iii), representing aromatic substances used 
in the process of the invention, --Y-- is preferably a direct link, --O--, 
or 
##STR15## 
where --X-- and --X'-- which may be the same or different are each a 
direct link or --O--, and --Z-- is --CO-- or --SO.sub.2 --. 
In reactant sub-class (a) of the invention, examples of the aromatic 
compound of formula (i) are as follows: 
##STR16## 
Of these, diphenyl ether and diphenyl are particularly preferred since the 
polymerisation of diphenyl ether according to the process of the invention 
can yield a polymer whose repeat units are the same as those of the 
currently commercially available aromatic polysulphone homopolymer having 
repeat units of formula 
##STR17## 
while the polymerisation of a mixture of diphenyl ether and diphenyl 
according to the invention can yield a copolymer having repeat units the 
same as those of the commercially available aromatic polysulphone 
copolymer having repeat units of formulae 
##STR18## 
In reactant sub-class (b) of the invention, examples of the aromatic 
compound of formula (ii) are as follows: 
##STR19## 
Of these diphenyl ether-4-sulphonic acid and dipheyl-4-sulphonic acid are 
particularly preferred since the polymerisation of the former can yield a 
polymer whose repeat units are the same as those of the commercially 
available aromatic polysulphone homopolymer mentioned above while the 
polymerisation of a mixture of the two can yield a copolymer having repeat 
units which are the same as those of the commercially available aromatic 
polysulphone copolymer mentioned above. 
In reactant sub-class (c) of the invention, examples of the aromatic 
compound of formula (iii) are as follows 
##STR20## 
while examples of the aromatic compound of formula (i) are as follows 
##STR21## 
Of these, diphenyl ether-4,4'-disulphonic acid and 
diphenyl-4,4'-disulphonic acid are particularly preferred as examples of 
compounds of formula (iii) while diphenyl ether and diphenyl are 
particularly preferred as examples of compounds of formula (i). Thus the 
polymerisation of diphenyl ether-4,4'-disulphonic acid with diphenyl ether 
can yield a polymer having repeat units which are the same as those of the 
commercially available polysulphone homopolymer mentioned above while a 
polymerisation with these monomers which additionally includes 
diphenyl-4,4'-disulphonic acid and/or diphenyl can yield a copolymer 
having repeat units which are the same as those of the commercially 
available aromatic polysulphone copolymer mentioned above. 
The conditions required for the polymerisation reaction to produce the 
aromatic polysulphone should be determined by experiment as they will 
often vary with the nature of the starting monomer (or monomers) used and 
with the desired properties (e.g. molecular weight) of the polymer being 
manufactured. Conveniently the pressure employed may be atmospheric 
pressure. A normal reaction temperature range is 40.degree. to 200.degree. 
C., particularly 50.degree. to 150.degree. C.

The present invention is now illustrated by the following Examples. 
EXAMPLE 1 
Diphenyl ether (17.0 g, 0.1 mole) was weighed into a 3-necked flask 
(capacity 250 ml) fitted with a motor-driven stirrer, internal 
thermometer, addition funnel and reflux condenser (protected with a drying 
tube), under a nitrogen blanket. 36 ml of triflouromethane sulphonic acid 
were added. A solution of analar 98% w/w sulphuric acid (10 g, approx. 0.1 
mole) in 20 ml trifluoromethane sulphonic acid was added drop-wise from 
the addition funnel into the stirred solution contained in the flask 
(which was not cooled). The residue in the addition funnel was washed into 
the flask with a further 10 ml of trifluoromethane sulphonic acid. In all, 
60 ml of trifluoromethane sulphonic acid (0.68 mole) were employed, the 
density of this material being 1.7. 
The solution in the flask after the addition of the trifluoromethane 
sulphonic acid was yellow/orange in colour and had become warm. The 
reaction mixture was heated (using an oil bath) to 100.degree. C. and 
maintained at this temperature for about 3.5 hours. The deep orange 
solution produced was allowed to cool and then poured into water whereupon 
a shining white polymeric solid precipitated out in what appeared to be 
substantially quantitative yield. This was washed with dilute NaOH, dilute 
HCl, water, methanol, and then ether and finally dried in a vacuum oven at 
85.degree. C. 
The polymer thus produced had an nmr spectrum which showed it to be an 
aromatic polysulphone consisting predominantly of the repeat units having 
the formula 
##STR22## 
The RV (dimethyl formamide) of this polymer was 0.15. 
EXAMPLE 2 
The procedure of Example 1 was substantially followed except for the 
following variations. The amount of diphenyl ether used was 34.0 g (0.2 
mole), the amount of analar 98% w/w H.sub.2 SO.sub.4 used was 19.93 g (0.2 
mole) and the total amount of trifluoromethane sulphonic acid used was 
again 60 ml (0.68 mole). Before the addition of the sulphuric acid, the 
contents of the flask (diphenyl ether dissolved in 20 ml of 
trifluoromethane sulphonic acid) were cooled to 3.degree. C. and during 
the addition of the sulphuric acid (dissolved in 20 ml trifluoromethane 
sulphonic acid) and the washing through with further trifluoromethane 
sulphonic acid (20 ml) the temperature of the flask contents was kept 
within the range 3-8.degree. C. During the addition, the solution in the 
flask retained a dark amber colour. 
The reaction mixture was heated at about 100.degree. C. for approximately 
10 hours. The deep red solution was worked up to yield a white polymer. 
The polymer was again found (by nmr spectroscopy) to consist predominantly 
of the repeat units of formula 
##STR23## 
The RV (dimethyl formamide) of this polymer was 0.19. 
EXAMPLE 3 
The same equipment as in Example 1 was employed. Diphenyl ether (17.0 g, 
0.1 mole) was weighed into the flask. 88 ml of trifluoromethane sulphonic 
acid were added and the flask placed in an ice bath to cool the mixture 
contained therein to 3.degree. C. A solution of analar 98% w/w sulphuric 
acid (9.98 g, 0.1 mole) in 44 ml trifluoromethane sulphonic acid was added 
dropwise from the additional funnel into the stirred solution contained in 
the flask. At the end of the addition (after about 40 minutes) the 
temperature of the liquid in the flask had risen to 4.degree. C. The ice 
bath was removed and the temperature of the liquid allowed to rise to 
18.5.degree. C. (over 25 minutes). The addition funnel was removed and 5.0 
g P.sub.2 O.sub.5 powder added (using a powder dispenser) through the free 
neck of the flask. The mixture was stirred without the application of heat 
for about 20 minutes when most of the P.sub.2 O.sub.5 dissolved and the 
solution became cherry red. The stirred mixture was heated (using an oil 
bath) to 100.degree. C. and maintained substantially at this temperature 
for over 21 hours. After about 3.7 hours a further 4.8 g of P.sub.2 
O.sub.5 were added, making a total of 9.8 g added altogether (0.069 mole). 
Samples (of about 3-5 ml) were periodically removed with a clean syringe 
each solution being injected into 200 ml demineralised water to yield a 
white lace-like precipitate which was filtered off. Unless otherwise 
specified, each precipitate was washed twice with water, and then once 
with methanol (filtering in between washes), and finally dried at 
90.degree. C. in a vacuum oven. Nmr spectroscopy showed them to be an 
aromatic polysulphone consisting predominantly of the repeat units having 
the formula: 
##STR24## 
with only about 2% of ortho-sulphonylation being present. 
The results of the sampling were as follows: 
3A (after 2 hours at 100.degree. C.)--RV of polymer 0.30. 
3B (after 3.5 hours at 100.degree. C.)--RV of polymer 0.44. 
3C (after 5 hours at 100.degree. C.)--RV of polymer 0.54. The polymer was 
compression moulded (320.degree. C.) into dark tough film. 
3D (after 21 hours at 100.degree. C.)--Polymer after precipitation divided 
into two approximately equal portions: 
portion a--worked up as per other samples to give polymer of RV 0.81; this 
was compression moulded (320.degree. C.) into dark tough film. 
portion b--steeped for 2 hours in gently boiling alcoholic dilute NaOH 
solution; filtered off and washed with distilled water, then methanol and 
dried at 100.degree. C. in a vacuum oven to give polymer of RV 0.82; this 
was compression moulded into tough yellow film. 
(All RVs measured in dimethyl formamide.) 
EXAMPLE 4 
The same equipment as in Example 1 was employed. Diphenyl ether (34.0 g, 
0.2 mole) was weighed into the flask and 176 ml of trifluoromethane 
sulphonic acid added. After cooling to 2.5.degree. C. (using the ice 
bath), a solution of analar 98% w/w sulphuric acid (19.96 g, 0.2 mole) in 
88 ml trifluoromethane sulphonic acid was added dropwise into the stirred 
solution in the flask over 1.25 hours. The ice bath was removed and 9.5 g 
P.sub.2 O.sub.5 powder added to the solution. The mixture was stirred 
without the application of heat for 45 minutes when all the P.sub.2 
O.sub.5 dissolved, the solution being cherry red. The stirred mixture was 
heated to 100.degree. C. and maintained substantially at this temperature 
for 25 hours. After about 5.0 hours a further 2.3 g of P.sub.2 O.sub.5 
were added, making a total of 11.8 g added altogether (0.083 mole). 
Sampling and sample work-up was effected as per Example 3 (unless 
indicated otherwise) apart from the samples being bigger (as indicated), 
all the polymers having the repeat units of formula as indicated in 
Example 3 with a predominantly all para structure. 
The results of sampling were as follows: 
4A (after 1 hour at 100.degree. C.)--The sample size was 10 ml. RV of the 
polymer was 0.25. 
4B (after 2 hours at 100.degree. C.)--The sample size was 10 ml. RV of the 
polymer was 0.31. 
4C (after 3 hours at 100.degree. C.)--The sample size was 10 ml. RV of the 
polymer was 0.35. 
4D (after 4 hours at 100.degree. C.)--The sample size was 10 ml. RV of the 
polymer was 0.37. 
4E (after 5 hours at 100.degree. C.)--The sample size was 60 ml. RV of the 
polymer was 0.40; some of this was compression moulded (330.degree. C.) to 
give dark tough film. 
4F (after 19 hours at 100.degree. C.)--The sample size was 20 ml. RV of the 
polymer was 0.45. 
4G (after 23 hours at 100.degree. C.)--The sample size was 50 ml. The 
polymer after precipitation washed twice with water, twice with methanol 
and dried at 80.degree. C. in a vacuum oven to give polymer of RV 0.48; 
some of this was compression moulded (320.degree. C.) into dark tough 
film. 
4H (after 25 hours at 100.degree. C.)--The remainder of the reaction 
mixture yielded polymer of RV 0.55; some of this (after further treatment 
by stirring in methanol/NaOH at 70.degree. C. for 2 hours) was compression 
moulded (360.degree. C.) into pale yellow tough film. 
(All RVs measured in dimethyl formamide.) 
EXAMPLE 5 
Diphenyl ether (17.0 g, 0.1 mole) was weighed into a flask (capacity 150 
ml) equipped with a magneticially-driven stirrer bar, and an addition 
funnel (connectable with a drying tube). The flask was placed in a bath of 
liquid paraffin on a magnetic-stirrer hot plate and charged with 20 ml 
trifluoromethane sulphonic acid. To the resulting stirred solution was 
added (at ambient temperature) over 30 minutes a solution of 
chlorosulphonic acid (11.7, 0.1 mole) in 40 ml trifluoromethane sulphonic 
acid. HCl gas was evolved (as observed in a Drechsel bottle). When HCl 
evolution had ceased (5 minutes after finishing the feed of sulphonic 
acids), the reaction mixture was heated to 80.degree. C. and stirred at 
this temperature for 48 hours. The resulting viscous solution was poured 
slowly into 250 ml cold water when a white polymeric lace precipitated. 
This was washed, macerated into a white powder and oven dried. 
The yield of polymer collected was 22 g (NB in this and subsequent 
Examples, no attempt was made to collect all the polymeric product in a 
quantitative manner); its nmr spectrum showed it to be an aromatic 
polysulphone consisting predominantly of the repeat units having the 
formula 
##STR25## 
with about 2% of ortho-sulphonylation being present. 
The RV (dimethyl formamide) of the polymer was 0.40. Some of the polymer 
was compression moulded (330.degree. C.) into dark tough film. 12 g of the 
polymer was stirred in methanol (containing a little dilute aqueous NaOH 
solution) at reflux temperature; the treated polymer was dried for 24 
hours at 150.degree. C. under vacuum. A sample of the treated polymer 
(which had RV of 0.39) was compression moulded (340.degree. C.) into pale 
yellow tough film. 
EXAMPLE 6 
The preceding Examples indicate that the reaction according to the 
invention of diphenyl ether and conc. sulphuric acid in the presence of 
trifluoromethane sulphonic acid yields predominantly the all para product 
having repeat units of formula 
##STR26## 
In this Example, the percentage of ortho-sulphonylation in this product, 
when formed starting from diphenyl ether-4-sulphonic acid, as a function 
of reaction temperature was determined. The experimental procedure was as 
follows. 
A 10 weight % solution of diphenyl ether-4-sulphonic acid in 
trifluoromethane sulphonic acid was made up in a small sample tube and 
portions transferred to nmr tubes which were then stored at the 
temperatures being studied. (The diphenyl ether-4-sulphonic acid itself 
was prepared by hydrolysing the corresponding sulphonyl chloride by 
refluxing in acetone--just sufficient acetone being used to dissolve the 
sulphonyl chloride. After several hours the solution was evaporated to 
dryness and the acid dried in a vacuum oven at 80.degree. C.) 
The products in the nmr tubes were examined by nmr spectroscopy, and the 
percentage of ortho-sulphonylation determined. The results are shown in 
the following table (the values given being those obtained when the % 
ortho-sulphonylation did not change on further storage at the selected 
temperature). 
______________________________________ 
Reaction Temperature 
(.degree.C.) % Ortho-Sulphonylation 
______________________________________ 
0 &lt;4 
20 4 
50 3.3 
80 2.0 
120 1.1 
______________________________________ 
It is seen that higher reaction temperatures favour the formation of the 
desirable all para product. 
EXAMPLE 7 
The same equipment as used in Example 5 was employed. Diphenyl ether (17.0 
g, 0.1 mole) was charged to the flask followed by 20 ml of difluoromethane 
sulphonic acid. (Difluoromethane sulphonic acid, which is not a currently 
commercially available material, may be prepared by reacting 
chlorodifluoromethane and aqueous sodium sulphite heptahydrate to form 
sodium difluoromethane sulphonate, heating this sodium salt with conc. 
sulphonic acid and distilling off the free difluoromethane sulphonic acid 
under reduced pressure.) To the resulting stirred solution was added (at 
ambient temperature) over 20 minutes a solution of chlorosulphonic acid 
(11.7 g, 0.1 mole) in 36 ml difluoromethane sulphonic acid. HCl was 
evolved as in Example 5. After the cessation of HCl evolution, the mixture 
was heated to 80.degree. C. and stirred at this temperature for 48 hours. 
The resulting viscous solution was poured slowly into water contained in a 
macerator and the resulting white polymeric precipate macerated, washed 
and dried in a vacuum oven at 80.degree. C. 
The yield of polymer collected was 22 g. Its nmr spectrum showed it to 
consist predominantly of the repeat units having the formula 
##STR27## 
with about 2% of ortho-sulphonylation being present. 
The RV (dimethyl formamide) of the polymer was 0.22. 
EXAMPLE 8 
The same equipment as used in Example 5 was employed. Diphenyl (15.42 g, 
0.1 mole) was charged to the flask and heated to 70.degree. C. (with 
stirring) when it melted. To the stirred melt (held at 
70.degree.-75.degree. C.) was added over 20 minutes a solution of 
chlorosulphonic acid (11.7 g, 0.1 mole) in 60 ml trifluoromethane 
sulphonic acid. At the start of the feed, the contents of the flask became 
a brown mobile slurry. When 25% of the feed had been added, the contents 
had become a dark red solution. HCl evolution commenced immediately on 
starting the feed and ceased about two minutes after its completion. The 
reaction mixture was stirred at 70.degree. C. for 68 hours. The resulting 
very viscous solution was poured slowly into 400 ml water contained in a 
domestic-type macerator to form an extremely tough pale-coloured lace. 
Attempts to macerate the lace encountered difficulty because the lace was 
so tough that it caused the macerator to stop. The lace was transferred to 
a commercial-type macerator and macerated into granules. The resulting 
product was dried in a vacuum oven at 136.degree. C. (some of the product 
first having been treated with methanol/aqueous NaOH as in Example 5). 
The yield of polymer collected was 17.5 g. Its nmr spectrum showed it to be 
an aromatic polysulphone consisting predominantly of the repeat units of 
formula 
##STR28## 
The polymer was found to be insoluble in dimethyl formamide. However, its 
RV was measured as a solution in trifluoromethane sulphonic acid (1% w/v 
at 25.degree. C.) and found to be 1.31. (This solution was sealed 
overnight and the measurement of RV repeated; it was found that the RV had 
risen to 3.8.) 
EXAMPLE 9 
Apart from the time and temperature of reaction, substantially the same 
procedure as used in Example 8 was employed (the reactants being the 
same), with the feed of chlorosulphonic acid plus trifluoromethane 
sulphonic acid being added to the stirred melt of diphenyl over 10 minutes 
at (72.degree.-65.degree. C.). HCl evolution was again observed. In this 
Example, however, the reaction mixture was stirred at 53.degree. C. for 25 
hours in order to achieve a product of lower molecular weight. The 
resulting viscous solution was again precipitated in water contained in a 
domestic-type macerator; this time, however, maceration therein yielded a 
fine pale-coloured powder which was filtered, washed with water (to remove 
acid), filtered again and finally dried over the weekend. 
The yield of polymer collected was 19.7 g. Its nmr spectrum showed it to be 
an aromatic polysulphone consisting predominantly of the repeat units of 
formula 
##STR29## 
The polymer was again found to be insoluble in dimethyl formamide and its 
RV was measured as a solution in trifluoromethane sulphonic acid (1% w/v 
at 25.degree. C.); this was found to be 0.16. (When remeasured after 
keeping the sealed solution overnight, the RV had risen to 0.58.) 
EXAMPLE 10 
A similar procedure to that used in Example 8 was employed, the main 
difference being that a mixture of diphenyl ether and diphenyl were used 
in place of the diphenyl. Thus a mixture of diphenyl ether (8.95g, 0.053 
mole) and diphenyl (8.12 g, 0.053 mole) was charged to the flask (with 
stirring) followed by 20 ml of trifluoromethane sulphonic acid; a green 
slurry was formed which was heated to 60.degree. C. with stirring to form 
a dark red solution. A mixture of chlorosulphonic acid (12.32 g, 0.106 
mole) and 43 ml trifluoromethane sulphonic acid was added dropwise over 10 
minutes. Gas evolution started immediately with the feed and virtually 
ceased within minutes of its completion. The mixture was stirred for 43 
hours at 70.degree. C. and the resulting viscous solution poured slowly 
into 400 ml of water contained in a macerator; the ensuing precipitate was 
macerated thoroughly. The precipate was nearly white in colour and 
consisted of feathery granules. The product was filtered, washed, treated 
with boiling water and finally (after again filtering) dried under vacuum 
at 136.degree. C. 
The yield of product collected was 21 g; it was found to dissolve cleanly 
and easily in dimethyl formamide. Its nmr spectrum showed it to be an 
aromatic polysulphone copolymer consisting predominantly of the repeat 
units of formulae 
##STR30## 
The RV (dimethyl formamide) of the copolymer was 0.38. 
EXAMPLE 11 
The equipment of Example 1 was employed. 4,4'-diphenoxy-benzophenone (18.3 
g, 0.05 mole) was weighed into the flask and 80 ml trifluoromethane 
sulphonic acid added with stirring. The stirred, deeply coloured, solution 
was cooled to -2.degree. C. and then a solution of 98% w/w sulphuric acid 
(5.0 g, 0.05 mole) in 20 ml trifluoromethane sulphonic acid added dropwise 
over 50 minutes. The stirred reaction mixture was heated with stirring in 
the range 87.degree.-105.degree. C. over 23 hours, 3.2 g of P.sub.2 
O.sub.5 being added after 21 hours. The resulting solution was poured into 
water to yield a white polymeric precipitate; this was washed and then 
dried in a vacuum oven. 
The yield of polymeric collected was 15 g. Its nmr spectrum showed it to be 
an aromatic polysulphone consisting predominantly of repeat units having 
the formula 
##STR31## 
The RV (dimethyl formamide) of the polymer was 0.38. X-ray analysis showed 
it to be amorphous. Its glass-transition temperature (Tg), as determined 
by Differential Scanning Calorimetry, was found to be 182.degree. C. 
EXAMPLE 12 
The equipment of Example 5 was employed. 4,4'-diphenoxy-diphenylsulphone 
(40.2 g, 0.1 mole) was charged to the flask and heated to 80.degree. C. 20 
ml of trifluoromethane sulphonic acid were added and the mixture stirred 
to form a red-orange solution. A mixture of chlorosulphonic acid (11.7 g, 
0.1 mole) and 40 ml trifluoromethane sulphonic acid was added dropwise to 
the stirred solution. A steady evolution of gas was observed. The mixture 
was maintained at 80.degree. C. for 40 hours. The viscous solution was 
poured into water contained in a macerator (as per previous examples) to 
isolate the polymer, which was washed and then dried at 110.degree. C. in 
a vacuum oven. 
The yield of product collected (which had a buff colour) was 40.8 g. Its 
nmr spectrum showed it to be an aromatic polysulphone consisting 
predominantly of repeat units of formula 
##STR32## 
or more simply 
##STR33## 
The RV (dimethyl formamide) of the polymer was 0.16. 
EXAMPLE 13 
The procedure of Example 12 was essentially repeated (same reactants and 
conditions) except that the reaction mixture was heated at 80.degree. C. 
for 65 hours instead of 40 hours. 
The product was again an aromatic polysulphone consisting predominantly of 
repeat units of formula 
##STR34## 
The RV (dimethyl formamide) of the polymer was 0.34. 
EXAMPLE 14 
The equipment of Example 5 was employed. Diphenyl ether (8.5 g, 0.05 mole) 
was charged to the flask and 40 ml trifluoromethane sulphonic acid added, 
with stirring, at room temperature. The disodium salt of diphenyl 
ether-4,4'-disulphonic acid (18.7 g, 0.05 mole) and P.sub.2 O.sub.5 (4.73 
g) were weighed into an addition funnel and added gradually to the stirred 
solution in the flask. [The disodium salt of diphenyl 
ether-4,4'-disulphonic acid was prepared as follows. To diphenyl ether (68 
g, 0.4 mole) was added dropwise with stirring conc. sulphuric acid (72 ml, 
1.35 mole). The temperature rose slowly and the acid addition was adjusted 
to maintain a temperature of 50.degree.-60.degree. C. The resulting 
viscous mixture was heated for 2 hours using a steam bath (attaining a 
temperature of about 85.degree. C.). After cooling, the mixture was poured 
into 300 ml of stirred demineralised water. To this was added 30 g of 
sodium hydroxide in 100 ml demineralised water; no precipate resulted so a 
further 48 g of sodium hydroxide in 150 ml demineralised water were added. 
A precipitate slowly appeared and the mixture was allowed to stand 
overnight. The resulting white precipitate was filtered off and oven dried 
at 80.degree. C. under vacuum. The yield of disodium salt collected was 
128.1 g.] The resulting cherry-red mixture was heated to 80.degree. C. 
with stirring. The solution so formed was heated (with stirring) at 
80.degree. C. for 18 hours and then at 90.degree.-100.degree. C. for a 
further 6 hours. The resulting clear cherry-red viscous solution was 
poured into water contained in a macerator to isolate the polymer (as per 
previous Examples). An off-white polymeric granular solid was obtained 
which was filtered off, washed with water, and dried in a vacuum oven 
overnight at 80.degree. C. 
The yield of polymer collected was 21.2 g. Its nmr spectrum showed it to 
consist predominantly of repeat units of formula 
##STR35## 
with about 3.6% of ortho-sulphonylation being present. The RV (dimethyl 
formamide) of the polymer was 0.14.