Processes of polymerizing and curing cationically-sensitive monomers such as cyclic ethers (e.g., epoxides), vinyl ethers, and N-vinyl compounds, in the presence of catalysts, specifically Lewis acids, such as boron trifluoride, aluminum chloride, and the like, are well known. However, many of these catalysts are highly corrosive to various substrates such as metals. Other known catalysts for the polymerization of cationically-sensitive monomers are undesirably toxic. Further, many of these acid catalysts rapidly catalyze the polymerization of the monomers with which they are admixed and cannot be used where a definite or prolonged shelf life and/or pot life is desired or required. Though some of these prior art acid catalysts can be used in a latent form, e.g. BF.sub.3.NH.sub.2 C.sub.2 H.sub.5, their latency is affected by moisture and prolonged latency is difficult to achieve; in addition, when these latent catalysts are activated, this gives rise to the aforementioned objectionable corrosiveness. Also, many known catalysts are not effective for polymerization of a broad range of cationically-sensitive monomers, e.g., for polymerization of both epoxides and cyclic siloxanes.
Various linear perfluoroaliphaticsulfonic acid anhydrides of the formula (RSO.sub.2).sub.2 O, where R is perfluoroalkyl, are described in U.S. Pat. No. 2,732,398. U.K. patent specification No. 1,120,304 discloses the use of the anhydride of trifluoromethanesulfonic acid as a catalyst for use in the polymerization of various cationically-sensitive monomers.
The utility of linear fluorocarbon sulfonic acid anhydrides (e.g., those derived from monofunctional perfluoroaliphaticsulfonic acids) as perfluoroaliphaticsulfonylation or acylation agents is also known. Use of the anhydride (CF.sub.3 SO.sub.2).sub.2 O as a trifluoromethanesulfonylation agent for formation of trifluoromethanesulfonamides by reaction with ammonia or amines is disclosed in Chemical Reviews, 77, 69-92 (1977). T. R. Forbus and J. C. Martin, J. Org. Chem., 44, 313 (1979) have disclosed the preparation of the mixed anhydride, CF.sub.3 SO.sub.2 OC(O)CF.sub.3, and its use as a trifluoroacetylation reagent for aromatic compounds. In these reactions, however, the above linear anhydrides produce not only the desired trifluoromethanesulfonylation or acylation product but also produce an equivalent amount of trifluoromethanesulfonic acid or salt thereof as by-product. For example, the reaction of (CF.sub.3 SO.sub.2).sub.2 O with ammonia provides trifluoromethanesulfonamide and an equivalent amount of the ammonium salt of trifluoromethanesulfonic acid as by-product. Such by-product is undesirable because of unfavorable economics in the preparation of the desired product.
Cyclic fluorocarbon acid anhydrides are highly desirable compositions since, in contrast to the above linear anhydrides, reaction of cyclic anhydrides with reagents such as ammonia or amines can produce useful difunctional products by ring-opening reactions without formation of the above-described undesirable by-products. Very few such cyclic anhydrides are known, however, because of many factors such as ring instability, or decomposition, e.g., decarboxylation, during the process of ring formation, or because of the inability of many difunctional acids to undergo ring closure by dehydration. Cyclic anhydrides such as perfluorosuccinic acid anhydride are well known and provide useful products by ring-opening reactions such as reaction with ammonia to produce ammonium salts of the perfluorocarboxylic acids containing terminal carboxamido (CONH.sub.2) functional groups. However, such cyclic anhydrides or their amide derivatives do not exhibit the catalytic properties of the cyclic anhydrides or sulfonamide derivatives of the invention described below.
The use of ammonia or amine salts of monofunctional perfluoroaliphaticsulfonic acids as latent catalysts for the polymerization of cationically-sensitive monomers is well known, see U.S. Pat. No. 3,842,019 and R. R. Alm, Modern Paint and Coatings, October, 1980, pages 88-92. However, the salts described in these references do not include a second functional group in the molecule (e.g., a sulfonamido group) as found in the ammonium or organoammonium salts of this invention.
USPTO Backgrounds
USPTO Backgrounds