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:
“Social questions are too sectional, too topical, too temporal to move a man to the mighty effort which is needed to produce great poetry. Prison reform may nerve Charles Reade to produce an effective and businesslike prose melodrama; but it could never produce Hamlet, Faust, or Peer Gynt.”
—George Bernard Shaw (1856–1950)
“the melodious but vast mass of today’s
Writing ...”
—John Ashbery (b. 1927)
“Of the quaking recruit, three pitched battles make a grim grenadier; and he who shrank from the muzzle of a cannon, is now ready to yield his mustache for a sponge.”
—Herman Melville (1819–1891)