MX-445 is a highly reactive liquid mixture of aluminum alkoxides in a technical white oil and behaves similarly to powdered AIP. MX-445 is capable of reacting with hydroxyl groups, carboxylic acid groups and with water to form aluminum organic compounds and hydroxy aluminum salts used in the preparation of catalysts, waterproofing compositions, and thickening agents.
Use as a Catalyst
Aldehydic or ketonic groups can be reduced using aluminum isopropoxide as a catalyst. The aldehydic or ketonic compounds are heated with aluminum isopropoxide and isopropyl alcohol. Since the reaction is reversible the by-product acetone is continually removed by distillation to enable it to go to completion. This reaction, which is known as the Meerwein Ponndorf reaction, is specific for carbonyl groups; other groups sensitive to reduction, such as nitro groups or ethylene linkages, are not attacked. It is a general method which is widely used. Chloro-aluminum di-isopropoxide, which can be prepared from aluminum isopropoxide, is also reported to be of value in the Meerwein Ponndorf reduction reaction.
The aluminum alkoxides can be used as catalysts in many other organic reactions. The reverse of the Meerwein Ponndorf reduction is the Oppenauer oxidation in which primary and secondary alcohols are oxidized to aldehydes or ketones. The Tischenko reaction is a disproportionation of aldehydes, similar to the Cannizzaro reaction.
In the Tischenko reaction aluminum alkoxide catalyses the conversion of aldehyde into ester. Aluminum alkoxides are useful catalysts for the alkylation of aromatic amines, mercaptans, phenols, etc and the preparation of amides from esters and amines. They are also of value in racemization, isomerization, transesterification and esterification reactions.
Reactions catalysed by aluminum isopropoxide can sometimes be used when alternative methods would cause undesirable side reactions. Nitro groups, double bonds, or substances sensitive to acid, alkali or water which may be attacked by alternative methods can be permitted in reactions catalysed by aluminum isopropoxide.