Monomeric and polymeric triarylsulfonium complex salts which may be prepared by contacting diarylsulfoxides or polymeric arylsulfoxides with aromatic compounds in the presence of an organosulfonic acid are described. An example is tris-(4-phenoxyphenyl)sulfonium methane sulfonate prepared by reaction of bis-(4-phenoxyphenyl)sulfoxide, diphenyl ether and methane sulfonic acid. The compounds demonstrate useful corrosion inhibiting properties.

BACKGROUND OF THE INVENTION 
This invention relates to triarylsulfonium complex salts. More 
particularly, the invention relates to triarylsulfonium organosulfonates 
and anion-exchanged derivatives thereof that have useful properties either 
with or without modification for use as corrosion inhibitors, 
phase-transfer catalysts, catalysts for hydrocarbon oxidation, 
flame-retardant additives, biological agents such as herbicides and animal 
growth promoters, flocculants in waste water treatment and mineral ore 
processing and refining, and as complex salt photoinitiators. The 
invention further relates to a novel process for preparing the 
triarylsulfonium organosulfonates of the invention. 
In U.S. Pat. No. 2,807,648, a process is described for the preparation of 
triarylsulfonium chlorides by the reaction of an aryl hydrocarbon, 
aluminum chloride, sulfur monochloride and chlorine. The process has 
proven difficult for commercial use due to the hazardous reactants 
involved. Furthermore, it has recently been discovered that the process 
does not prepare highly pure triarylsulfonium salts as had been previously 
thought. For example, in U.S. Pat. No. 4,173,476 at column 6, line 36 et 
seq. it is disclosed that the reaction mixture formed according to this 
process contains up to about 55 percent of 
diphenyl(4-(phenylthiophenyl)sulfonium chloride with only minor amounts of 
the expected triphenylsulfonium chloride. 
S. Smiles in J. Chem. Soc., 696-708 (1906) at page 701, described a process 
for preparing triarylsulfonium sulfates by heating, e.g., 
di(p-ethoxyphenyl)sulfoxide with ethoxybenzene in the presence of sulfuric 
acid. The process disadvantageously introduced quantities of sulfonated 
benzene derivatives. Also disclosed by the same reference was a process 
for preparing triarylsulfonium phosphate salts by reacting diphenyl 
sulfoxide with ethoxybenzene in the presence of phosphoric acid. 
The above-identified U.S. Pat. No. 4,173,476 describes a further process 
wherein triphenylsulfonium phosphates were prepared by reacting diphenyl 
sulfoxide with diphenyl sulfide in the presence of phosphorus pentoxide. 
It would be desirable to prepare triarylsulfonium salts without 
disadvantageously contaminating the desired product with derivatives 
formed by interaction of the catalyst and the reactants. 
It would be further desirable to provide a process for preparation of 
triarylsulfonium salts that may suitably employ non-activated and 
relatively unreactive aromatic compounds in place of reactive aromatic 
compounds such as alkoxybenzenes, or diphenyl sulfide employed in the 
prior art. 
Finally, it would be desirable to prepare novel triarylsulfonium salts of 
high purity having desirable properties for use in numerous industrial 
applications. 
SUMMARY OF THE INVENTION 
According to the invention an improved process is provided for preparation 
of monomeric and polymeric triarylsulfonium complex salts comprising 
compounds corresponding to the formula: 
##STR1## 
wherein Ph is phenylene, diphenylene or oxydiphenylene; 
A and B independently each occurrence are hydrogen, C.sub.1-4 alkyl, 
phenyl, alkoxy or phenoxy; 
m is an integer greater than or equal to zero, equal to the number of 
sulfoxide moieties in the complex salt; 
Z is a counterion selected from the group consisting of RSO.sub.3.sup.-, 
BF.sub.4.sup.-, PF.sub.6.sup.-, AsF.sub.6.sup.- and SbF.sub.6.sup.-, where 
R is lower alkyl, phenyl or tolyl; and 
n is an integer greater than or equal to one, equal to the number of 
sulfonium moieties in the complex salts. 
The process comprises contacting a diarylsulfoxide or polymeric 
arylsulfoxide corresponding to the formula: 
##STR2## 
with an aromatic compound of the formula B--Ph--H in the presence of an 
organosulfonic acid of the formula R--SO.sub.3 H at elevated temperatures, 
wherein A, Ph, B and R are as previously defined; and 
m' is an integer greater than or equal to one, equal to the number of 
sulfoxide moieties in the compound. 
The organosulfonate counterions may be exchanged for the other counterions 
specified by contacting the triarylsulfonium complex salts with alkali 
metal salts of the desired counterion. 
Further included in the invention are the novel monomeric and polymeric 
triarylsulfonium complex salts formed by the process. 
DETAILED DESCRIPTION OF THE INVENTION 
The diarylsulfoxides and polymeric arylsulfoxides employed in the invention 
are either known compounds or they may be prepared according to known 
techniques. Suitable monomeric compounds include diphenyl sulfoxides, 
C.sub.1-4 alkyl-, C.sub.1-4 alkoxy- or phenoxy-substituted diphenyl 
sulfoxides, di(biphenyl)sulfoxides, and C.sub.1-4 alkyl-, C.sub.1-4 
alkoxy- or phenoxy-substituted di(biphenyl)sulfoxides. 
Preferred monomeric diarylsulfoxides are diphenyl sulfoxides 
ring-substituted in the para positions with the above groups. A preferred 
reactant is bis(4-phenoxyphenyl)sulfoxide which produces 
(4-phenoxyphenyl)-substituted sulfonium compounds having improved 
corrosion-inhibiting properties. 
Polymeric arylsulfoxides are easily prepared, for example, by the Lewis 
acid catalyzed reaction of the previously identified aromatic compounds, 
B--Ph--H, with thionyl chloride. A preferred aromatic compound is diphenyl 
ether, thereby producing polymeric arylsulfoxides of the formula: 
##STR3## 
Suitably, m' in such polymeric arylsulfoxides is from 2 to about 30, 
preferably from about 2 to about 10. 
The aromatic compounds which are reacted with the above diarylsulfoxides 
and polymeric aryllsulfoxides include benzene, monosubstituted C.sub.1-4 
alkyl- or C.sub.1-4 alkoxybenzenes, phenylbenzene and diphenyl ether. 
Preferred are aromatic compounds capable of entering into Friedel-Crafts 
reactions. Preferred aromatic compounds are toluene, methoxybenzene and 
diphenyl ether. A most preferred aromatic compound is diphenyl ether. 
The organosulfonic acids for use according to the invention include methane 
sulfonic acid and other alkyl sulfonic acids, as well as benzene sulfonic 
acid and toluene sulfonic acid. Methane sulfonic acid is preferred. 
The previously identified reactants are combined in a reaction vessel and 
heated to elevated temperatures. Suitable temperatures are from about 
70.degree. C. to about 150.degree. C., preferably from 80.degree. C. to 
about 110.degree. C. The time for the reaction is dependent on the 
reaction conditions employed and the degree of completion desired for the 
reaction. Generally, the reaction is completed within about 24 hours. 
The reactants may be combined in any order. An excess of organosulfonic 
acid is employed. Suitably from about 5 to 10 equivalents of acid are 
employed per equivalent of sulfoxide reactant. The aromatic reactant may 
also be present in an excess over that required for the reaction. 
Suitably, amounts of aromatic compound from 1 equivalent to about 10 
equivalents per equivalent of sulfoxide reactant are employed. 
A reaction solvent may be employed as an aid in mixing and contacting the 
reactants. Suitable solvents include inert organic liquids such as 
halogenated aliphatics, e.g., methylene chloride, ethylene chloride, etc. 
It is recognized, particularly for the polymeric complex sulfonium salts of 
the invention, that complete sulfonium ion formation of all sulfoxide 
groups within the polymer may not be accomplished. Typically, the polymer 
comprises repeating sulfur-containing moieties, about 5-90 percent or more 
of which have been converted to the corresponding sulfonium ion form, 
e.g., the ratio of m/n in the formula for the polymeric complex salts is 
from about 95/5 to about 10/90. Preferably, about 10-50 percent of the 
sulfur moieties are in the sulfonium ion form. 
In view of the number of repeating sulfoxide units in the previously 
defined polymeric arylsulfoxide, the polymeric triarylsulfonium complex 
salts of the invention will have total numbers of sulfur-containing 
moieties, e.g., m+n, of from about 2 to about 30 and preferably from about 
2 to about 10. 
The complex salt reaction product may be recovered from the reaction 
mixture by ordinary techniques and purified if desired by repeated 
washings of water or organic solvents or by recrystallization. The complex 
salts may be used in some applications, e.g., as corrosion inhibitors, in 
the crude form. The organosulfonate counterion may easily be converted to 
other counterions if desired by simple ion-exchange. For example, 
contacting the complex salts with sodium tetrafluoroborate in, e.g., a 
methanol solution, will result in preparation of the corresponding 
tetrafluoroborate salt. Suitable counterions that may be exchanged for the 
organosulfonates according to this procedure include anionic remnants of 
strong protonic acids formed by removal of a hydrogen ion from an acid of 
the formula HMX.sub.n where M is a metal, X is halogen and n is an integer 
signifying the number of halogens present. Preferred are such counterions 
as BF.sub.4.sup.-, PF.sub.6.sup.-, AsF.sub.6.sup.- and SbF.sub.6.sup.-, 
which are useful in initiating the polymerization of cationically 
polymerizable monomers. Particularly preferred triarylsulfonium salts in 
this regard are tris-(4-phenoxyphenyl)sulfonium salts of the above 
counterions.

SPECIFIC EMBODIMENTS 
Having described the invention the following examples are provided as 
further illustration and are not to be construed as limiting. 
EXAMPLE 1 
A mixture of 10 g (28.2 mmole) of bis-(4-phenylphenyl)sulfoxide, 26 g 
(282.0 mmole) of toluene and 27.11 g (282.0 mmole) of methane sulfonic 
acid were refluxed (ca. 110.degree. C.) for 24 hours. The mixture was 
poured into 300 ml of water plus 300 ml of toluene. The sulfonium salt 
precipitated as a gummy solid and was purified by decanting the water and 
toluene, adding further quantities of water to the gummy residue, and 
stirring. The water was again decanted and the procedure repeated with 
toluene. The residue was dissolved in 250 ml of chloroform and dried by 
extracting with saturated aqueous sodium chloride solution followed by 
treatment with magnesium sulfate. The chloroform was then evaporated and 
the residue dissolved in methanol. The methanol was then evaporated to 
leave 9.14 g of sulfonium salt with methanol of solvation. Analysis by 
nuclear magnetic resonance spectroscopy indicated the residue contained by 
weight 14.5 percent methanol, 20.5 percent 
phenyl-bis-(4-phenylsulphenyl)sulfonium methane sulfonate and 65 percent 
4-methylphenyl-bis-(4-phenylphenyl)sulfonium methane sulfonate. This 
represented a 60.1 percent yield of sulfonium salts. 
EXAMPLE 2 
A mixture of 192.22 g of methane sulfonic acid, 54.46 g of 
bis-(4-methoxyphenyl)sulfoxide and 500 ml of anisole was heated at 
80.degree. C. for 22 hours. The mixture was poured into 1000 g of ice 
water and extracted three times with 500-ml portions of ether. The aqueous 
phase was neutralized with 50 percent aqueous sodium hydroxide and 
extracted five times with 500-ml portions of chloroform. The combined 
chloroform phases were dried with magnesium sulfate and the chloroform was 
removed on a rotary evaporator to give 105.76 g of 
tris-(4-methoxyphenyl)sulfonium methane sulfonate with residual chloroform 
of solvation. 
EXAMPLE 3 
A mixture of 42.51 g of bis-(4-phenoxyphenyl)sulfoxide,187.23 g of diphenyl 
ether and 105.71 g of methane sulfonic acid was heated at 100.degree. C. 
for 24 hours with stirring. The mixture was poured into 700 g of ice water 
and the resultant aqueous and sulfonium layers extracted four times with 
200-ml portions of ether and five times with 200-ml portions of 
chloroform. The combined chloroform extracts were dried with magnesium 
sulfate and the chloroform removed on a rotary evaporator to give 91.66 g 
of tris-(4-phenoxyphenyl)sulfonium methane sulfonate with 1.7 equivalents 
of chloroform of solvation. This represents a 100 percent yield. 
The sulfonium salt was converted in quantitative yield to the corresponding 
sulfonium tetrafluoroborate salt by treatment with sodium 
tetrafluoroborate in methanol. The crystalline product was recovered by 
filtration. 
EXAMPLE 4 
A mixture of 40.45 g phenyl sulfoxide, 340.42 g of diphenyl ether and 
192.20 g of methane sulfonic acid was heated at 100.degree. C. for 68 
hours. The disappearance of phenyl sulfoxide was monitored by gas 
chromatography. Workup substantially according to the method of Example 3 
gave 49.24 g of diphenyl-4-phenoxyphenylsulfonium methane sulfonate (54.6 
percent yield). 
EXAMPLE 5 
The reaction conditions of Example 4 were substantially repeated by 
reacting bis-(4-methylphenyl)sulfoxide and diphenyl ether for 24 hours at 
80.degree. C. followed by further reaction at 100.degree. C. for 24 hours. 
Yield of bis-(4-methylphenyl)-4-phenoxyphenylsulfonium methane sulfonate 
was 71.6 percent. 
EXAMPLE 6 
A mixture of 3 g of bis-(4-t-butylphenyl)sulfoxide, 30 ml of t-butylbenzene 
and 9.17 g of methane sulfonic acid was heated at 100.degree. C. for 24 
hours. The mixture was poured into 100 ml of water and extracted with four 
50-ml portions of ether followed by five 50-ml portions of chloroform. The 
chloroform extracts were dried and the chloroform removed on a rotary 
evaporator to give 1.03 g of tris-(4-t-butylphenyl)sulfonium methane 
sulfonate (20.6 percent yield). 
EXAMPLE 7 
A mixture of 50.24 g of bis-(4-phenoxyphenyl)sulfoxide, 140.58 g of anisole 
and 124.93 g of methane sulfonic acid was heated at 100.degree. C. for 24 
hours. The mixture was poured into 700 g of ice water and worked up 
substantially according to the previously described procedure to give 67.6 
g of 4-methoxyphenyl-bis-(4-phenoxyphenyl)sulfonium methane sulfonate (91 
percent yield). 
EXAMPLE 8 
A mixture of 30 g of bis-(4-n-butoxyphenyl)sulfoxide, 147.4 g of diphenyl 
ether and 83.22 g of methane sulfonic acid was heated at 100.degree. C. 
for 23 hours and worked up substantially according to the previously 
described procedure to give 49.51 g of a product mixture containing 
bis-(4-n-butoxyphenyl)-4-phenoxyphenylsulfonium methane sulfonate and 
dealkylated by-products. 
EXAMPLE 9 
A mixture of 5.8 g of bis-(4-phenoxyphenyl)sulfoxide and 2.55 g of diphenyl 
ether in 18 ml of methylene chloride was added dropwise over a period of 3 
hours to 7.21 g of methane sulfonic acid at 100.degree. C. The methylene 
chloride was distilled off as the addition proceeded. The mixture was then 
heated at 100.degree. C. for 28 hours and worked up substantially 
according to the procedure previously described to give 7.74 g of 
tris-(4-phenoxyphenyl)sulfonium methane sulfonate (81.3 percent yield). 
EXAMPLE 10-POLYMERIC SULFONIUM COMPLEX SALT 
A solution of 17.02 g of diphenyl ether and 11.9 g of thionyl chloride in 
100 of methylene chloride was added dropwise with stirring over a period 
of 2 hours to a solution of 14.67 g of aluminum chloride in 15 ml of 
nitromethane plus 100 ml of methylene chloride at 0.degree. C.-10.degree. 
C. The mixture was stirred for 2 hours at 25.degree. C. after the addition 
was complete, then poured into 200 g of ice water. The organic phase was 
separated and extracted with two 200-ml portions of water and one 100-ml 
portion of saturated aqueous sodium chloride. The methylene chloride was 
removed on a rotary evaporator and the residue dissolved in chloroform 
(100 ml). The chloroform solution was dried with magnesium sulfate and 
added dropwise to vigorously stirred ether (500 ml). The precipitated 
polymer was filtered off and vacuum dried to give 18.96 g (87.7 percent 
yield) of a polymeric arylsulfoxide corresponding to the formula 
##STR4## 
wherein m' was about 10 as determined by end group analysis by .sup.1 H 
nuclear magnetic resonance spectroscopy. 
A mixture of 15 g of the polymeric sulfoxide prepared above, 118.06 g of 
diphenyl ether and 66.66 g of methane sulfonic acid was heated at 
100.degree. C. for 24 hours. The mixture was worked up substantially 
according to the previously described process of Example 1 to give a 
polymer in which 40 percent of the original sulfoxide groups were 
converted into sulfonium salts as determined by .sup.1 H nuclear magnetic 
resonance spectroscopy analysis.