CHM 237 Lab 10 Report
Synthesis of 4‐methylcyclohexene via Dehydration of 4‐methylcyclohexanol
Heston Allred
TA: Christine Woolley
Thursday 1:05-4 pm
Laboratory Experiment #10
Abstract 4-methylcyclohexanol was synthesized to 4-methylcyclohexene using dehydration. 4-methylcyclohexanol was heated to reflux and the subsequent distillate (4-methylcyclohexe) was collected. It was then purified using sodium chloride to separate products and an anhydrous solid was then added and filtered. The resulting product had a mass of 0.399 g and a percent yield of 41%. The product was positively identified and characterized as 4-methylcyclohexene via IR and Br2 test.
Introduction To synthesize 4-methylcyclohexene from 4-methylcyclohexanol the starting material can be dehydrated resulting in the desired compound. For dehydration to be possible the OH group on the 4-methylcyclohexene must first be converted into H2O by means of an acid-base reaction using a strong acid catalyst such as phosphoric acid and sulfuric acid. The H2O will then become the favored leaving group and leave on its own resulting in the formation of a carbocation in excess water. The water will remove the acidic hydrogen on the carbocation producing the desired alkene as well as regenerating the acid catalyst (fig. 2). A time effective way to collect the 4-methylcyclohexene is to heat the reaction to reflux as it is taking place. This allows the product to be separated from the starting materials by means of the boiling point discrepancy between the isolated alkene (101-102C) and the starting alcohol (171-173C). After the distillate is collected any impurities of water and phosphoric acid can be extracted by adding sodium chloride, drying the resulting organic layer with an anhydrous solid, and filtration. IR of both the starting alcohol and the resulting alkene can be compared as a means of identification and characterization as well as a Br2
Heston Allred
TA: Christine Woolley
Thursday 1:05-4 pm
Laboratory Experiment #10
Abstract 4-methylcyclohexanol was synthesized to 4-methylcyclohexene using dehydration. 4-methylcyclohexanol was heated to reflux and the subsequent distillate (4-methylcyclohexe) was collected. It was then purified using sodium chloride to separate products and an anhydrous solid was then added and filtered. The resulting product had a mass of 0.399 g and a percent yield of 41%. The product was positively identified and characterized as 4-methylcyclohexene via IR and Br2 test.
Introduction To synthesize 4-methylcyclohexene from 4-methylcyclohexanol the starting material can be dehydrated resulting in the desired compound. For dehydration to be possible the OH group on the 4-methylcyclohexene must first be converted into H2O by means of an acid-base reaction using a strong acid catalyst such as phosphoric acid and sulfuric acid. The H2O will then become the favored leaving group and leave on its own resulting in the formation of a carbocation in excess water. The water will remove the acidic hydrogen on the carbocation producing the desired alkene as well as regenerating the acid catalyst (fig. 2). A time effective way to collect the 4-methylcyclohexene is to heat the reaction to reflux as it is taking place. This allows the product to be separated from the starting materials by means of the boiling point discrepancy between the isolated alkene (101-102C) and the starting alcohol (171-173C). After the distillate is collected any impurities of water and phosphoric acid can be extracted by adding sodium chloride, drying the resulting organic layer with an anhydrous solid, and filtration. IR of both the starting alcohol and the resulting alkene can be compared as a means of identification and characterization as well as a Br2