Reduction of Carboxyl Groups

From the analysis of the results on the preliquefaction chemistry, it was found that the preliquefaction process results in reduction of carboxyl groups, partial crosslinking of the structure and some bond breaking resulting in hi er chloroform extractables. The effect of this preliquefaction process on subsequent liquefaction is a high yields of liquids. 

The reduction of carboxyl groups and their reaction with diazonium... 

Aldehydes are more generally prepared by electrolytic reduction of amides, the reduction of carboxylic adds being possible only when they are activated by a strongly electron-withdrawing group (58). 

Reduction of carboxylic acids and esters, aldehydes, and nitriles, and the hydro-boration of alkenes with diborane in non-ethereal solvents is highly effective (Table 11.8), but reduction of nitro groups or cleavage of arena-halogen bonds does not occur [1]. However, in spite of the potential advantages, very little use appears to have been made of the procedure. 

Appropriate activation of carboxyl groups enables reduction of aliphatic carboxylic acids to the corresponding aldehydes. The electroreduction of iminium salts prepared from aliphatic carboxyKc... 

REDUCTION OF CARBOXYLIC ACIDS CONTAINING SUBSTITUENTS OR OTHER FUNCTIONAL GROUPS... 

An important example of this type of reaction is the formation of esters, which was discussed previously in connection with the reactions of alcohols in Section 15-4D. Similar addition-elimination mechanisms occur in many reactions at the carbonyl groups of acid derivatives. A less obvious example of addition to carboxyl groups involves hydride ion (H 0) and takes place in lithium aluminum hydride reduction of carboxylic acids (Sections 16-4E and 18-3C). 

Aldehydes are intermediate ill oxidation level, and thus the aldehyde functional group can be installed by either reduction of carboxylic acid derivatives or oxidation of alcohols. Aldehydes are rarely installed without a change of oxidation level. One difficulty is that they undergo both oxidation and reduction readily. Special methods are required to stop at the aldehyde stage rather than proceeding by further reduction or oxidation. 

Reduction - Carbon dioxide evolved when coal is heated with a suitable catalyst (such as copper carbonate or copper sulfate) is a measure of carboxyl groups. 

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