Effective mass yield is defined as the percentage of the mass of the desired product relative to the mass of all non-benign materials used in its synthesis. Hudlicky et al. suggests the following equation:
Effective mass yield (%) = mass of products × 100 / mass of non-benign reagents
This metric requires further definition of a benign substance. Hudlicky defines it as “those by-products, reagents or solvents that have no environmental risk associated with them, for example, water, low-concentration saline, dilute ethanol, autoclaved cell mass, etc.”. This definition leaves the metric open to criticism, as nothing is non-benign (which is a subjective term) and the substances listed in the definition have some environmental impact associated with them. The formula also fails to address the level of toxicity associated with a process. Until all toxicology data is available for all chemicals and a term dealing with these levels of “non-benign” reagents is written into the formula the effective mass yield is not the best metric for chemistry.
Read more about this topic: Green Chemistry Metrics
Famous quotes containing the words effective, mass and/or yield:
“... effective magic is transcendent nature ...”
—George Eliot [Mary Ann (or Marian)
“Where mass opinion dominates the government, there is a morbid derangement of the true functions of power. The derangement brings about the enfeeblement, verging on paralysis, of the capacity to govern. This breakdown in the constitutional order is the cause of the precipitate and catastrophic decline of Western society. It may, if it cannot be arrested and reversed, bring about the fall of the West.”
—Walter Lippmann (1889–1974)
“Yet cease your ire, you angry stars of heaven!
Wind, rain, and thunder, remember earthly man
Is but a substance that must yield to you.”
—William Shakespeare (1564–1616)