Ethylene effect copper

The use of silver fluoroborate as a catalyst or reagent often depends on the precipitation of a silver haUde. Thus the silver ion abstracts a CU from a rhodium chloride complex, ((CgH )2As)2(CO)RhCl, yielding the cationic rhodium fluoroborate [30935-54-7] hydrogenation catalyst (99). The complexing tendency of olefins for AgBF has led to the development of chemisorption methods for ethylene separation (100,101). Copper(I) fluoroborate [14708-11-3] also forms complexes with olefins hydrocarbon separations are effected by similar means (102). 

The effect of bath additives on the electrocodeposition of alumina-copper has been studied. Chloride ion was found to significantly inhibit incorporation of alpha alumina in an acidic copper bath [27, 51], whereas thallium ions, cesium ions, and tetra-ethylene pentamine were promoters [25, 32]. 

The kinetics and mechanism for oxygen transfer between 4-cyano-V,V,-dimethylaniline V-oxide and a C2-capped mexo-tetraphenylporphyrinatoiron(III) and mc5 o-tetrakis(pentafiuorophenyl)-porphyrinatoiron(III) have been established. Addition of a copper(II) porphyrin cap to an iron(II)-porphyrin complex has the expected effect of reducing both the affinities and rate constants for addition of dioxygen or carbon monoxide. These systems were studied for tetradecyl-substituted derivatives solubilized by surfactants such as poly(ethylene oxide) octaphenyl ether. ... 

Fig. 9.2.15 Effect of NaOH concentration on the copper powders obtained from the reduction of CuO in a sorbitol-ethylene glycol solution (A) no NaOH (B) [NaOH] = 10-2 mol L l. (C) [NaOH] = 5 X 1(T2 mol L I (D) [NaOH] = 10-1 mol L-1. (From Ref. 17.)...

Copper(I) and silver(I) complexes are exceptions of the general trend in stability constants with electron-donating or attracting substituents. Thus most known 7i-complexes of silver and copper are less stable than their respective ethylene complexes (154 156). The steric hindrance introduced by the substituents seems to have a major effect in those systems. 

A systematic attempt to correlate the catalytic effect of different surfaces with their adsorptive capacity was made by Taylor and his collaborators. Taylor and Burns, for example, investigated the adsorption of hydrogen, carbon dioxide, and ethylene by the six metals nickel, cobalt, palladium, platinum, iron, and copper. All these metals are able to catalyse the hydrogenation of ethylene to ethane, while nickel, cobalt, and palladium also catalyse the reduction of carbon monoxide and of carbon dioxide to methane. 

A classical example of this type of competitive reaction is the conversion of ethanol by a copper catalyst at about 300°C. The principal product is acetaldehyde but ethylene is also evolved in smaller quantities. If, however, an alumina catalyst is used, ethylene is the preferred product. If, in the above reaction scheme, B is the desired product then the selectivity may be found by comparing the respective rates of formation of B and C. Adopting the slab model for simplicity and remembering that, in the steady state, the rates of formation of B and C must be equal to the flux of B and C at the exterior surface of the particle, assuming that the effective diffusivities of B and C are equal ... 

Unsaturated ethers. The efficient insertion of carboalkoxycarbenes into the O—H bond of alcohols catalyzed by Rh(II) acetate (5, 571-572) extends to reactions with unsaturated alcohols. For this reaction copper(II) triflate is usually comparable to rhodium(II) alkanoates. Insertion predominates over cyclopropanation in the case of ethylenic alcohols. In reactions with acetylenic alcohols, cyclopropenation can predominate over insertion because of steric effects, as in reactions of HC=CC(CH3)2OH where the insertion/addition ratio is 36 56. 

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