Proton sealing materials

The use of isoxazole derivatives in organic synthesis is of great interest, but little has been done on the utilization of such compounds as a part of a diene system in [4 + 2]-cycloadditions. 3-Methyl-5-vinylisoxazole 236 gave cycloaddition reactions in a sealed tube in benzene solution at 120°C for 3 days. With the dienophiles acrolein and methyl acrylate, aromatiza-tion of the isoxazole ring via a 1,3-proton shift occurs readily under the reaction conditions, allowing the direct isolation of compounds 237, which are also detected in the mass spectrum of the raw reaction material. The reactions are regioselective (85H2019). 

Only in very rare cases can zeolites be used direetly in the form in which they were originally synthesized. For many larger-seale industrial applications, for instance, the synthetically obtained zeolite powders must be formed into larger attrition and crush-resistant partieles using inorganic binder materials [33]. In most cases a thermal treatment in air (calcination) is at least required to decompose the organic template, to dehydrate the zeolite and to desorb impurities [35]. This holds particularly true if the proton form of a zeolite is desired from the ammonium form for aeid eatalysis. 

PEM fuel cells have emerged as the most common type of fuel cell under development today. As stated above, they also are commonly referred to as proton exchange membrane fuel cells based on the key characteristic of the solid electrolyte membrane to transfer protons from the anode to the cathode. The solid electrolyte avoids problems caused by liquid electrolytes used in other systems, and the temperature range of <100°C enables rapid start-up under low temperature operation, with operation possible down to subfreezing temperatures. The lower temperature also allows a wider range of materials to be used and enables relatively easy stack design in terms of sealing issues and material selection. This type of fuel cell is the most feasible for use under transportation applications. 

Three general methods of copolymerization were attempted (1) radical solution polymerization in an evacuated sealed glass tubes, (2) redox emulsion polymerization in water solution, and (3) radical polymerization (either in solution or neat) cast between mylar sheets to form a thin membrane film and initiated imder a uv lamp. The third method proved to be the best for forming membrane materials that could easily be tested for proton conductivity in an in-plane conductivity cell. This method was used most extensively and produced a large number of viable membrane materials. 

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