CHEM 233 Lecture Notes - Lecture 9: Semicarbazone, Boiling Point, Semicarbazide

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The purpose of this lab was to hydrate a terminal alkyne (2-methyl-3-butyn-2-ol) into a ketone (3-hydroxy-3-methyl-2-butanone) by properly heating under reflux, steam distillation, extraction, use of drying agents, and rotary evaporation. The product was characterized and analyzed by percent yield and infrared spectroscopy. Electrophilic addition involves in hydration of alkynes to the carbon-carbon triple bond that is yielding a ketone. For this experiment, the terminal alkyne undergoes the electrophilic addition. The role of mercuric ion in this reaction reacts with the triple bond to create a vinyl cation which is further stabilized by conversion to a cyclic mercurinium ion. Then water attacks the more substituted carbon involved in the initial triple bond. After several transfers of proton, mercuric ion is lost to give a substituted vinyl alcohol which is converted to a carbonyl group (c=o) thru tautomerization. Alkyne hydration reactions are regioselective which means that they follow the.