Mm. Sharma, Some novel aspects of catalysis with solid acids - (Prof. N.R. Dhar Memorial Lecture, November 11, 1999), NATL ACAD S, 23(1-2), 2000, pp. 1-12
Solid acids as catalysts are environmentally Friendly and highly versatile.
These catalysts can be used in aqueous, polar and non-polar medium and eve
n in the gas phase. Even superacidic catalysts have been developed. These c
atalysts offer non-corrosive atmosphere. Special emphasis has been given to
cationic ion exchange resins and acid treated clays as catalysts although
the heterogenised heteropolyacids and zeolites do have their importance.
A variety of industrially important reactions based on alkylation, etherifi
cation, esterification, hydrolysis, oligomerisation etc, can be advantageou
sly carried out with these catalyst and some of these are highlighted. Ofte
n rate and selectivity with solid acids are superior to that realised with
homogeneous catalysts and in many cases reactions that are not feasible wit
h homogeneous catalysts occur with solid acids. A variety of organic transf
ormations can be carried out.
Solid acid catalysts can be used in Distillation Column Reactors and in Ext
ractive Reaction modes and thus offer a number of advantages associated wit
h capital and energy cost. Even impurity removal can be carried out in such
reactors. Solid acid catalysts can also be exploited for separation of clo
se boiling isomeric/non-isomeric substances.