Supported fluorocarbonsulfonic acid polymers and an improved method for their preparation
AssigneeThe Dow Chemical Company
InventorsDavid L. Childress, John D. Weaver, Emmett L. Tasset
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Abstract
This invention discloses improved heterogeneous acid catalysts and a method for preparing these catalysts. A heterogeneous acid catalyst has been prepared by coating a carrier with an aqueous emulsion containing a fluorocarbonsulfonic acid polymer in the sulfonyl fluoride form, removing the excess water, heating to a temperature above the softening point of the polymer for a time, and then converting the polymer to the active sulfonic acid form. The substrate has pores of about 0.1 micrometers or greater and a surface area of about 20 m.sup.2 /g or less.
Claims16
The composition comprising a fluorinated polymer having pendant sulfonic acid groups, or halogen derivatives of sulfonic acid groups, on a support which support has an average pore diameter greater that about 0.1 micrometer and a surface area of less than about 20 m.sup.2 /g.
The method of supporting a fluorinated polymer having pendant chains containing sulfonyl groups on a support, the method comprising the steps:
- (a) soaking a substrate having a pore size of at least about 0.1 micrometer and a surface area of less than about 20 m.sup.2 /g with a dispersion that contains a fluorinated polymer which has pendant chains containing sulfonyl groups;
- (b) removing the dispersing medium from the mixture;
- and
- (c) converting the sulfonyl groups to sulfonic acid or sulfonate groups.
Dependencies are inferred from the claim text.