Utilization of piperazine for interphase catalytic systems

Phase transfer catalysis (PTC) is an important modern synthetic method where reagents are located in different phases. Generally, it is transfer of inorganic reagent (base or nucleophile) from aqueous medium or solid phase to organic phase. Current catalysts for „classic" PTC are –onium salts (N, P, S), macrocyclic polyesters (crown-ethers), aza- -macrobicyclic ethers (cryptands), polyethylenglycols (PEGs) and their dimethylethers. Both in laboratory and industry, the most widely used catalysts are ammonium salts for their good price and availability. The other trend which is implementing within the frame of „Chemistry for sustainable development" are supported catalysts. Generally catalyst is bound on inorganic or organic polymer support and the system is insoluble in water and organic solvents as well. Supported catalyst can be easily separated from the reaction mixture and it can be reused again. Piperazine (A) as secondary cyclic 1,4-diamine offers two functional centers on its nitrogen atoms – one for preparation of quaternary catalytical place and second for immobilization on solid support, organic polymer.