Simulated moving bed (SMB) is a continuous, counter-current binary sep
aration technique, more and more used in the separation of fine chemic
als and pharmaceuticals. The first industrial SMB units have now been
implemented in the pharmaceutical industry, for the separation of opti
cal isomers. This article describes some of the most important feature
s which now belong to SMB dedicated to applications in the fine chemis
try: The separation of optical isomers, a very critical technical prob
lem for the pharmaceutical industry is now well solved at large scale
thanks to the SMB technique. MB is often not used alone, but when poss
ible in coupling with enantioselective crystallization (the SMB is use
d to pre-purify a crude material with a high robustness and an enhance
d productivity, while crystallization is used to ''polish'' the enanti
omer). Very short columns (less than 10 cm long) have been optimized t
o take advantage of very small stationary phase particles now used in
chromatography. For chiral separations, they allow to dramatically dec
rease the overall separation process cost. Softwares play a much more
important role than before: simulation tools allow to numerically opti
mize the SMB parameters for nearly all kinds of molecules with a very
limited number of experiments and to help validate the separation proc
ess with simulated ''worst cases'', while improved control softwares a
llow to circumvent some technical difficulties due to the asymmetry of
SMB systems.The way to consider the SMB and the associated evaporatio
n unit in a single unit operation lead to a well-defined process which
may reduce the number of in-process controls and the consequences of
non conformity of the product. Beside liquid SMB, this article introdu
ces a more recently developed SMB process, working with supercritical
eluent. This technique might find interesting applications especially
in the separation of certain lipidic compounds.