Silver catalyzed carbon monoxide

Silver oxide forms a brownish-black, odorless powder with a decomposition point of 200 Celsius. Sunlight catalyzes the break down into silver and oxygen. Silver oxide is also easily decomposed by hydrogen, carbon monoxide, and many metals. It is insoluble in water, but is freely soluble in ammonia and dilute nitric acid with formation of salts. It is prepared by treating a silver nitrate solution with sodium hydroxide. 

Promoters are often needed in addition to the actual catalyst itself. In general promoters increase the rate of a desired reaction this can occur because of a general increase in reaction rates or because of an increase in selectivity towards one product by comparison to others. Most promoters tend to be specific to a particular reaction and catalyst but some promoters can accelerate different reactions. For example potassium (usually added as K2O) promotes the silver catalyzed ethylene oxidation to ethylene oxide (Section 2.4), and also promotes carbon monoxide hydrogenation over Fe catalysts (Section 4.8). 

Cyclic exponents of the same elimination type are of particular interest. Thus, numerous cyclopentanones photolytically decarbonylate to give 1,4-dienes (p. 876 ff. in Ref. 108)). With thujone (194) this [l,2,(3)4]-elimination of carbon monoxide proceeds quantitatively to give 195 109). With silver nitrate the norcaradiene 196 yields 197 (95%)110) apparently regioselectively, and the [l,2,(3)4]-elimination of methanethiol from 198 to give 199 was realized thermally (16%), acid-catalyzed (59%), and photochemiciiily (ca. 5%)105). For the acid-catalyzed reaction (acetic acid, 100 °C) a non-stereospecific process has been proved 105). 

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