Yield (chemistry)

According to the Elements of Chemical Reaction Engineering manual, yield refers to the amount of a specific product formed per mole of reactant consumed.

The Compendium of Chemical Terminology defined yield as the "ratio expressing the efficiency of a mass conversion process.

[1]: 33  In their 2002 publication, Petrucci, Harwood, and Herring wrote that Vogel's Textbook names were arbitrary, and not universally accepted, and depending on the nature of the reaction in question, these expectations may be unrealistically high.

[7] They wrote that knowing the stoichiometry of a chemical reaction—the numbers and types of atoms in the reactants and products, in a balanced equation "make it possible to compare different elements through stoichiometric factors.

The limiting reagent determines the theoretical yield—the relative quantity of moles of reactants and the product formed in a chemical reaction.

[citation needed] In their 1992 publication General Chemistry, Whitten, Gailey, and Davis described the theoretical yield as the amount predicted by a stoichiometric calculation based on the number of moles of all reactants present.

Yields are typically obtained in this manner to accurately determine the quantity of product produced by a reaction, irrespective of potential isolation problems.

[citation needed] In their 2010 Synlett article, Martina Wernerova and organic chemist, Tomáš Hudlický, raised concerns about inaccurate reporting of yields, and offered solutions—including the proper characterization of compounds.

[11] After performing careful control experiments, Wernerova and Hudlický said that each physical manipulation (including extraction/washing, drying over desiccant, filtration, and column chromatography) results in a loss of yield of about 2%.

Thus, isolated yields measured after standard aqueous workup and chromatographic purification should seldom exceed 94%.