procedures for carrying out this reduction or activation are well established in liquid phase reactors such as those used in liquid phase methanol and liquid phase shift processes the catalyst is suspended in an inert liquid during operation the most efficient and economical way to activate the catalyst prior to beginning liquid phase operation is to reduce the catalyst after it has been suspended in the liquid a technique which is referred to as 34 in situ 34 activation activating the catalyst in the presence of a liquid has proven to be a significant technical challenge catalyst loadings can vary in a liquid phase reactor over a range from about 5 wt catalyst to about 50 wt catalyst as the catalyst loading is varied slurry properties such as slurry viscosity may change drastically to further complicate the activation process prior to the development of the present method unsuccessful catalyst activations were often experienced particularly for high catalyst loadings both in the laboratory and in large pilot plants by unsuccessful activation it is meant that the full activity of the catalyst has not been achieved at the end of the activation process moreover no remedial procedure could be found that would successfully complete the activation process i e achieve full catalyst activity if the initial attempt at activation was unsuccessful as mentioned earlier initial attempts at in situ activation of cuo zno al 2 o 3 catalyst slurries were based on established procedures for activating these catalysts in conventional gas phase reactors in a conventional gas phase fixed bed reactor the catalyst activation is accomplished by very careful control of the reductant concentration and reactor temperature normally a procedure typically starts with a low hydrogen concentration e g 0 3.