In chemical synthesis, obtaining product(s) with high purity is a crucial issue from both academic and industrial viewpoints. Higher purity of the product(s) means higher quality and a lower chemical production costs. Sometimes, purification and separation processes are very laborious and lead to significant impacts on the final price of the desired product(s). Simple and new synthetic methods for the preparation of highly pure product(s) have always been a challenge for synthetic and industrial chemists. In this paper, the relationship between the mass of reactants, quantity amount of each substance, and number of elementary entities, which are very important in obtaining the stoichiometric ratio of reactants, is first reviewed. Then, we show that using a nonstoichiometric ratio of reactants is a crucial and easy method in some organic reactions for obtaining products with high purity.
