This review article covers the research work that has been conducted in sol
id-electrolyte membrane reactors (SEMR). An overview of the types of solid
electrolytes and their applications in heterogeneous catalysis is first pre
sented, followed by a survey of SEMR studies published until 1998, Earlier
and recent developments are discussed. The technoeconomic aspects and the r
equirements to be met for further development into industrial practice are
presented and discussed.