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Download fileAdding Crystals To Minimize Clogging in Continuous Flow Synthesis
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posted on 2018-11-27, 00:00 authored by Gaurav Giri, Lu Yang, Yiming Mo, Klavs F. JensenFor many carbon–carbon
and carbon–nitrogen bond-forming
reactions, the stoichiometric formation of inorganic salt crystals
limits continuous flow synthesis by causing precipitation, agglomeration,
and ultimately clogging of the reactor. We describe a new method of
mitigating uncontrolled clogging by adding crystals into the reactant
stream. Adding seed crystals of the inorganic salt byproduct shifts
the crystallization profile from uncontrolled nucleation to controlled
heterogeneous growth. Reactions with the addition of high quality
crystals show less agglomeration compared to the unseeded reaction.
We realize the formation of high quality seeds using multiple methods
including filtration and settling. Modeling enables balancing of the
reaction rate and deposition of the salt onto seed crystals to prolong
reactor operating times without clogging.