Nafion hypohalites

Journal of Fluorine Chemistry, 2 1 (1982)

249-252

249

Received:May281982

PRELIMINARY

NOTE

NAFION HYPOHALITES

DARRYL D. DESMARTEAU* Kansas State University,

Manhattan,

Kansas

66506

(U.S.A.)

SUMMARY The perfluorinated verted

ionomers

to the hypochlorite

perature.

The hypochlorite

tion with a mixture

by reaction

hypobromite

groups can be con-

of the acid with ClF at low temto the hypobromite

by reac-

In this work Nafion - 511 manufac-

was utilized.

of the polymer

sions of the Nafion

sulfonate

can be converted

of Br2 and Cl*.

tured by the DuPont Company functionalization

containing

These unique

in a variety to the methyl

hypohalites

of new reactions.

allow

Conver-

and trifluoromethyl

deriva-

tives are described.

Interest search

in perfluorinated

is very high.

industry

Electrolytic

are commanding

ials as catalysti"and We have previously CF3S020H RfS020X

ionomers

and n-C4FgS020H

* Present Department

sources

address

El1

can be converted

of electrophilic

of these mater-

reagent i3'is growing

to the corresponding

[4,51 These hypohalites yield. halogen

re-

for the chlor-alkali

and utilization

supported

and chemical

shown that the perfluoroalkanesulfonic

(X = Cl, Br) in excellent

markable

cell membranes

much attention as polymer

in technology

rapidly.

acids hypohalites are re-

and are the basis of consider-

:

of Chemistry,

Clemson

0022-1139/82/0000-0000/$02.75

University,

Clemson,

SC 29631

(USA).

0 ElsevierSequoia/Printedin The Netherlands

250 able new and interesting explore

whether

converted

related

chemistry.

t5-91

It was therefore

polyperfluorosulfonic We report

to the hypohalites.

of Nafion-511*

to the corresponding

the utilization

of these compounds

of interest

to

acids could be similarly

here the facile conversion

hypochlorite

and hypobromite

in the covalent

and

functionalization

of the polymer. Granular

Nafion-511

form by treatment weight.

as the potassium

to the acid

with HCl and dried under vacuum at 90-100°C

The equivalent

weight was then determined

value was used in subsequent The hypochlorite Nafion-H

salt was converted

chemical

was prepared

to constatil

by titration

and this

conversions.

in high yield

by reaction

of the

with ClF at low temperature.

Nafion-H

+ ClF

The resulting namic vacuum expected

-l~~Ftol~~O'C~

pale yellow

tile decomposition

products

4

Nafion-Cl

is rapid at 22°C.

burst of C12, followed ogy with CF3S03Cl,

Iodometric

equivalents.

and the decomposition

+ HF

solid was then purified

for 3 h at -30°C.

oxidizing

Nafion-Cl

I

by pumping

analyses begins

gave 99.4% of the

to decompose

at -15°C

Direct gas inlet of the vola-

at 22°C into a mass spectrometer

by SO3 and minor

the decomposition

under dy-

fluorocarbon

probably

shows a

fragments.

proceeds

By anal.

in a related

manner. CF3S03Cl Nafion-Cl However,

-

CF3S03* -+

Nafion.

the immobility

formation

+ Cl. + Cl.

CF3C1 + SO3

----f

---+ Polymer

of the resulting

polymer

of Cl2 instead of a chlorofluorocarbon

+ Cl2 +

so3

radical

leads to the

polymer

analogous

to

CF3C1. *Nafion

is a registered

a perfluorosulfonic potassium

trademark

of the DuPont Co.

acid ion exchange

salt with an equivalent

resion,

weight

Nafion-511

supplied

of 'I,1100.

is

as a granular

251 The reaction Nafion-Br

with a 1:l mixture

of Br2 and Cl2 forms

in high yield.

Nafion-Cl Iodometric Nafion-Br

of Nafion-Cl

+ BrCl

analyses

-50B~~10"c+

analogous

The utility

SED reaction6

solid, thermally to Nafion-Cl

of Nafion-Br

oxidizing

at 22°C forming

Br2.

in synthesis

with CH3Br and CF3Br.

gives rise to the corresponding

methyl

f CH3Br

-50 to 22°C 16hr CH Br+ ’ 3

Nafion-CH3

+ Br2

Nafion-Br

+ CF3Br

-50 to 22°C 16hr, CF3Br+

Nafion-CF3

+ Br2

91% yield and CF3Br,

from Nafion-H

to Nafion-Br

based on the equivalents and the amount

mal stability

and do not readily

decompose

The resulting

to Nafion-ester

of acid, the amount

of Br2 formed.

can be illustra-

esters

Nafion-Br

The conversion

equivalents.

stable at O"C, but it decomposes

of these new hypohalites

ted by the reaction

+ Cl2

gave 93.3% of the expected

is an orange

in a manner

Nafion-Br

The esters

in high yield.

preceeded

of recovered

exhibit

in CH3Br

high ther-

below 2OO"C, as indicated

by

mass spectrometry. We believe

Nafion-X

(X = Cl, Br) offers

for the functionalization tives will be useful studies

exciting

new possibilities

of Nafion and that these new polymer

in many ways,

ranging

from synthesis

deriva-

to fundamental

of ionomers.

ACKNOWLEDGEMENT

The support gratefully

acknowledged.

were provided Tillway

of this research

by the National

Funds for the purchase

Science

technical

assistance.

is

of the mass spectrometer

by the NSF and the U.S. Army Research

provided

Foundation

Office.

Arvind

252 REFERENCES

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