|When zinc chloride is
supported on the clay, montmorillonite, it shows good activity at
catalysing Friedel-Crafts alkylation. Collaboration between a Merseyside
company and the University of York led to the worldwide marketing
of a range of similar catalysts known as 'Envirocats'.
This is now the basis of the synthesis
of parabenzenediphenyl used for coating fax paper.