Platinum catalysts polymers

This method of preparation is suitable for producing primary alkyl lactates but is unsatisfactory for /3-methallyl lactate because the strong mineral acid catalyzes the rearrangement of methallyl alcohol to isobutyraldehyde. Methyl lactate can be made conveniently (80-85% yield) by heating 1 mole of lactic acid condensation polymer with 2.5-5 moles of methanol and a small quantity of sulfuric acid at 100 for 1-4 hours in a heavy-walled bottle, such as is used for catalytic hydrogenation with a platinum catalyst. 

The PEMFCs require expensive polymer membrane (e.g., Nation ), and operate at a low temperature (e.g., 80°C). Although low temperature reduced the cost of material, the heat generated at low temperatures is more difficult to remove. Alternate proton conducting membranes (e.g., inorganic polymer composites) that will operate at a high temperature (e.g., 200°C) are required. The expensive platinum catalyst used for electrochemical reactions can be poisoned by even trace amounts of carbon monoxide in the hydrogen fuel stream. Hence, a more tolerant catalyst material needs to be developed. 

Si-H bonds add across olefins over platinum catalysts. This reaction (hydrosi-lation) is used in silicone polymer manufacture, when the silane is a hydrogen bearing oligo(alkylsiloxane). With some types of olefin there have been reports of runaways to explosion because of unexpectedly fast reaction. Dangerous substrates recorded are 2-allylphenols and ethenylsiloxanes. Very low levels of catalyst (ppm) and good cooling are recommended. 

Cho, Y. H., Park, H. S., Cho, Y. H., Jung, D. S., Park, H. Y, and Sung, Y. E. Effect of platinum amount in carbon supported platinum catalyst on performance of polymer electrolyte membrane fuel cell. Journal of Power Sources 2007 172 89-93. 

Linear polycarbosilanes and polycarbosiloxanes-especially those containing arylene units in the chain-have specific physico-chemical properties which can be applicable in heat-resistant materials [29-31]. Phenylene-silylene-ethylene-polymers, which may serve as potential substrates for applications as membrane materials are usually obtained in the presence of platinum catalysts [32], although other transihon-metal complexes have also been tested in this process. 

Hydroxymethyl furfural. 2,5-diformylfuran (DFF) is a furan derivative that has many uses, including use as a polymer building block. By utilizing a platinum catalyst supported on carbon, and running the reaction in water at high temperatures, DFF is produced as the major product in neutral solution. If low temperatures and high pH are employed, 2,5-furandicarboxylic acid results. 

As described in the first part of this section, MVt can reduce protons to give H2 with a platinum catalyst. The presence of Pt colloid in the photoreaction mixture of Ru(bpy) + polymer complex (derived from water soluble homopolymer of Vbpy), MV2+ and EDTA gave H2 gas at almost the same rate as the mixture containing Ru(bpy)j + instead of polymer complex401 (see Scheme 1). The turnover number of the Ru polymer complex exceeded 25 in 1 h s irradiation. The water insoluble polymer complex (5) showed almost the same activity when used as suspensions in a mixture of MeOH/H20 =1/1. 

Table 3. Light-Induced Hydrogen Production by Platinum Catalysts Prepared in the Presence of Various Polymers...

In a similar manner, the hydrosilylation-polymerization of diallyl bisphenol A (278) with 275 in the presence of a platinum catalyst affords polymer 279 that possesses a relatively high glass transition temperature for siloxane polymers (Tg = 28-34 °C) and... 

Proton exchange membrane (PEM)—Solid organic polymer electrolyte with platinum catalyst. It requires hydrogen fuel and is suited for automobiles. 

Another characteristic of the proton-conducting membrane is that it has low permeability to oxygen and hydrogen in the gas phase so that a high coulombic efficiency exists [7], In addition, in this fuel cell type, the electrodes are normally formed on a thin layer on each side of a protonconducting polymer membrane used as an electrolyte, and platinum catalysts are required for both the anode and the cathode for the proper operation of this fuel cell [9],... 

The PAFC is based on an immobilized phosphoric acid electrolyte. The matrix universally used to retain the acid is silicon carbide, and the catalyst for both the anode and cathode is platinum [8], The active layer of platinum catalyst on a carbon-black support and a polymer binder is backed by a carbon paper with 90% porosity, which is reduced to some extent by a Teflon binder [6,9]. 

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