Carbon as reducing agent

All of the preparation procedures for the oxide promoted catalysts (T-O shared one common feature, heat-treatment of the oxide impregnated Ft on carbon catalysts in an inert atmosphere at elevated temperature, usually around 900 C. If an "alloy" phase of Ft with the metal of the metal oxide is formed by this heat-treatment, thermal reduction would have to occur with carbon as reducing agent, e.g. 

The reactivity of various carbons as reducing agents for CrgOj has been investigated the results show that the relative reactivities of the carbons in this solid-solid reaction are comparable with those previously observed in the course of studies with oxygen or even iron oxides i.e. reactions directly or indirectly operating with the gaseous phase). 

Kiba et al. propose the separation of technetium from rheniiun by carbon tetrachloride extraction using potassium ethyl xanthate as reducing agent. 

The action of carbon monoxide (CO) upon solutions of copper salts leads to the formation of cuprous CO complexes that have pronounced activity as reducing agents ... 

Carbinolamines, 87 Carbodiimides, 205-222 reaction with alcohols, 170 Carbon monoxide, as reducing agent, 336 a-Carbonyl azo compounds, 324, 326 Caro s add (permonosulfuric add), 408 oxidation with, 409 preparation of, 409 Chloramine T, 377 Chloroacetylenes 120-122 4-Chloro-l, 2-butadiene, 33 Chlorocyclohexenyl acetylene, 121 1 -Chloro-2-JV,N-diphenylaminoacetylene, 128-129... 

In Eq. 15.7 the carbon monoxide itself is acting as reducing agent. 

Some species are also able to utilize formate or formaldehyde as reducing agents.435 These compounds are oxidized to C02, the reducing equivalents formed being used to reduce C02 to methane. Carbon monoxide can also be converted to C02. 

Carbanions, alkoxides and alkylamides all behave as reducing agents under appropriate circumstances. The effect of hyperconjugative interaction between a C—H bond and negative charge on an adjacent atom has already been noted, and, in most but not all cases, the reductions are accommodated within the framework of hydride transfer from an activated C—H bond to an electrophile, usually carbonyl carbon. 

In those cases where carbon can not be used as reducing agent some other methods are used for reduction. Various methods of extraction used are listed below ... 

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