Reaction in Presence of Water
An alternative classification with broader scope is suggested by Yujiro Hayashi as he describes certain organocatalytic Aldol reactions as taking place in the presence of water. The observed effect in these reactions is not rate acceleration (that would be On Water) but happens to be increase in enantioselectivity.
In the context of organocatalysis both concepts of on-water reactions and in-the-presence-of-water reactions have been criticized in 2007 as not so environmentally friendly by Donna Blackmond. According to Blackmond, separation of reaction product from the water phase usually requires organic solvent anyway and in reported aqueous systems the water phase can in reality be less than 10% of the total reaction mixture with another component forming the actual solvent. Blackmond also notes that in reported instances, the observed rate-acceleration in presence of water is in fact due to water suppressing reaction deactivation.
Read more about this topic: On Water Reaction
Famous quotes containing the words reaction in, reaction, presence and/or water:
“Christianity was only a very strong and singularly well-timed Salvation Army movement that happened to receive help from an unusual and highly dramatic incident. It was a Puritan reaction in an age when, no doubt, a Puritan reaction was much wanted; but like all sudden violent reactions, it soon wanted reacting against.”
—Samuel Butler (1835–1902)
“In contrast to revenge, which is the natural, automatic reaction to transgression and which, because of the irreversibility of the action process can be expected and even calculated, the act of forgiving can never be predicted; it is the only reaction that acts in an unexpected way and thus retains, though being a reaction, something of the original character of action.”
—Hannah Arendt (1906–1975)
“What quarrel, what harshness, what unbelief in each other can subsist in the presence of a great calamity, when all the artificial vesture of our life is gone, and we are all one with each other in primitive mortal needs?”
—George Eliot [Mary Ann (or Marian)
“I believe that water is the only drink for a wise man: wine is not so noble a liquor; and think of dashing the hopes of a morning with a cup of warm coffee, or of an evening with a dish of tea! Ah, how low I fall when I am tempted by them! Even music may be intoxicating. Such apparently slight causes destroyed Greece and Rome, and will destroy England and America.”
—Henry David Thoreau (1817–1862)