CHEM 211 Chapter Notes - Chapter 8.4-8.7: Nucleophile, Hydrolysis, Tetrahydrofuran
8 Dec 2016
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Chapter 8. 4: electrophilic addition of hydrogen halides to alkenes. Cold concentrated sulfuric acid dissolves alkenes: forms alkyl hydrogen sulfates, steps: 1. forms carbocation by donating electrons to a proton on sulfuric acid. 2. carbocation reacts with sulfate to form alkyl hydrogen sulfate: this is regioselective reaction, and markovnikovian. Alkyl hydrogen sulfates can make alcohols by being hydrolyzed in heated water: maokovnikov addition of h and oh. Chapter 8. 5: electrophilic addition of hydrogen halides to alkenes. Hydration of an alkene is just the reverse of the dehydration of an alcohol. For the hydration of an alkene, it is best to use a dilute acid and lower temperature: for dehydration it"s the opposite, it"s best to use a concentrated acid and a high temperature. 1. oxymercuration: water and mercuric acetate add to the double bond. 2. demercuration: sodium borohydride reduces the acetoxymercury group and replaces it with hydrogen.
