In 1971 Charles M. Starks first coined the term “phase-transfer catalysis”. This term described a solution to the heterogeneity problem that arises when substances of a reaction are in different phases of the reaction mixture. Traditionally this problem was solved by issuing an appropriate mutual solvent, but by adding a small quantity of an agent which transfers one reactant across the interface into the other, the reaction can precede smoothly even in the case of heterogeneous phase systems. Starks found that organic-soluble Quaternary ammonium or phosphonium cations, Q+, were suitable agents for the transport of anions from the aqueous phase to the organic phase.

The focus in phase-transfer catalysis has mainly been on structures such as protected prochiral glycine derivatives and malonates, and less attention has been paid to substrates with a higher pKa. Since all research that addresses this type of phase-transfer catalysis is from the beginning of the 1980’s to early 1990’s, it would be preferable to evaluate the categories of catalysts that have been developed since then.

Phase Transfer Catalysis (PTC) is utilized as a part of the commercial manufacturing of more than $10 billion of chemicals each year. PTC is likewise utilized as a part of prevention of pollution, its treatment and for the impurities removal in waste and product streams. The demand of PTC is increased in the Chemical industries due to several convincing advantages it provides, especially for lessening the cost in making organic chemical as well as pollution prevention. The scope of PTC can be figured out by considering the scope of reactions to which PTC can be applied. The 1700 patents along with 8000 publications on PTC are in around 30 noteworthy reactions classifications. This scope of PTC utilization is amazingly wide and is one of the most important reasons behind the increased demand of PTC in chemical industries.

Regardless of market conditions, process scale or country of manufacture, the ability of increase the isolated yield of a reaction is always a basic method in order to decrease its cost, prevent pollution and improve the raw material usage. PTC provides higher isolated yield because of the higher selectivity achieved by taking advantage of the high flexibility in designing the microenvironment of the reaction. This is one of the main reasons that chemical industries have increased demand of PTC.

A phase transfer catalyst is dis-solvable in the two solvents, and it conveys anions of inorganic salts into natural solvents and returns them to the water phase. The Phase Transfer Catalysis reaction is generally carried out with easy work-up procedures and under mild conditions, which is also a main reason behind its increased industrial uses and smooth bath processing for chemical industry.