Catalysts used in amination reactions

In aminations requiring copper, it appears that copper ammonia cations complex with the chloro compound and that this complex addition compound acts as a cyclic catalyst by reacting with ammonia, —OH ion, and the amine.  

Dehydration Catalysts. In the production of amines from alcohols and ammonia or from alcohols and various amines, catalysts prepared by dehydrating alumina or silica gel are generally used. For specific reactions, these catalysts are promoted with various metals, their oxides or salts. For example, a dehydration catalyst has been made by incorporating aluminum phosphate in alumina gel prior to dehydrating the gel. An amination catalyst made by treating absorptive alumina with calcium and copper nitrates, followed by calcination and then reduction with hydrogen in a vapor-phase reactor, was used to produce an excellent yield of mono-methylaniline from aniline and methanol.  

Catalysts which are effective in hydrogenation and dehydrogenation procedures are often used to obtain amines from alcohols and ammonia or amineSi The above copper-containing catalyst may be considered in this category. In the vapor-phase production of aliphatic amines from alcohols 

Very good results have been obtained with foraminate catalysts (i.e., Ni, Co, and Cu catalysts) described below. When butanol was aminated over a copper foraminate catalyst, the per-pass conversion was 96 per cent and a 97 per cent deld of a mixture of mono-, di-, and tributylmnine was obtained. The operating conditions were mole ratio, butanol NHs Hj, 1 1.25 3.0 temperature, 250 C pressure, 17 atm liquid space velocity, 0.22 hr-i. 

The surface extraction of one constituent of an alloy has received increasing attention during recent years as a means whereby an active metal catalyst, such as nickel or copper, can be produced in a robust granular form. As these catalysts are wholly metallic, they are very good heat conductors, a property which sometimes can make them exceptionally suitable for use in strongly exothermic reactions. 

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