Phase transfer catalyst Catalyst as we know basically are used to start up or speed up a reaction, without undergoing any permanent change, a catalyst never involves in the reaction. Phase transfer catalysis is a special form of heterogeneous catalysis. In a chemistry we can define Phase transfer chemistry(PTC) as a catalyst which facilitates the migration of a reactant from one phase into another phase where the reaction takes place. Phase transfer catalysis speed up the process, get more output and remove the need for more costly solvents. PTC helps the ionic salts to be soluble in organic state otherwise they are only soluble in aqueous state. There are mainly two types of PTC's where PTC for anions reactant are Quaternary ammonium salts and PTC for cations are often crown ether. General advantages of PTC: 1. 2. 3. 4. 5. 6. 7.
Elimination of organic solvents. Use of simple and inexpensive reactants High yield and purity of products. Simplicity of the procedure. Highly scalable Low energy consumption and low investment cost. Minimal industrial waste.
Quaternary ammonium salts Quaternary ammonium salts also known as quats are one of the well used Phase Transfer Catalyst. They are prepared with the reaction called as quanternization in which alkylation and tertiary amines with a halocarbon. Major applications of ammonium salts are as disinfectants, surfactants, fabric softeners and as antistatic agent. Crown Ether Crown ether are cyclic chemical compounds that consist of a ring containing several ether groups. Their major applications lies in their use as Phase Transfer catalysts. The most common crown ether are oligomers of ethylene oxide. Advantages of PTC over homogeneous alternatives: 1. It includes less costly reagents. 2. It is “Green chemistry�. Which has given it more industrial expansion. 3. Easy to perform and highly scalable reactions. Due to the main purpose of green chemistry industries today are getting more and more involved with the production of PTC and in addition the production cost of phase transfer catalyst are low which has given the needed boost to its production.