Cyclohexanol
Nate Rhodes
The Synthesis of Alkenes: Dehydration of Cyclohexanol
Organic Chemistry Lab 1
Tuesday 8:00 11/08/11
Paul Jackson
Abstract: The goal of this experiment was to form cyclohexene from cyclohexanol through a dehydration reaction. Cyclohexene was successfully synthesized according to the bromine test performed and the IR spectra. There was a percent yield of cyclohexene of 76.1%.
Introduction:
Alkenes, hydrocarbons containing at least one carbon-carbon double bond, are important functional groups in natural and synthetic compounds. One method that they can be synthesized is through elimination reactions, which form alkenes with the net loss of a leaving group and an H+ on an alpha carbon. Atoms must be attached to adjacent carbons in order to be eliminated. Elimination reactions occur most commonly through E1 and E2 mechanisms. The specific mechanism that occurs depends on various conditions. The various conditions include leaving groups, substrate structure, the nature of the base, and the solvent. Both mechanisms will occur in the presence of a good leaving group. Examples of good leaving groups include I- and Br-, where a poor leaving group includes F- and OH-. An E2 reaction works best with a secondary or tertiary carbon because primary carbons have more competition for SN2 reactions. Additionally, the E2 pathway occurs in one step and is referred to as a bimolecular concerted reaction. The concentration of substrate and the concentration of the base are important in determining the rate of an E2 reaction. An E1 reaction works best with a primary or secondary carbon. E1 rates are determined by the concentration of substrate and are not affected by the concentration of the base. The rate determining step is the intermediate step in which a carbocation is formed. The leaving group substrate bond is broken during the rate determining step. If the leaving group involved in an elimination reaction is a water molecule, the reaction will be a
The Synthesis of Alkenes: Dehydration of Cyclohexanol
Organic Chemistry Lab 1
Tuesday 8:00 11/08/11
Paul Jackson
Abstract: The goal of this experiment was to form cyclohexene from cyclohexanol through a dehydration reaction. Cyclohexene was successfully synthesized according to the bromine test performed and the IR spectra. There was a percent yield of cyclohexene of 76.1%.
Introduction:
Alkenes, hydrocarbons containing at least one carbon-carbon double bond, are important functional groups in natural and synthetic compounds. One method that they can be synthesized is through elimination reactions, which form alkenes with the net loss of a leaving group and an H+ on an alpha carbon. Atoms must be attached to adjacent carbons in order to be eliminated. Elimination reactions occur most commonly through E1 and E2 mechanisms. The specific mechanism that occurs depends on various conditions. The various conditions include leaving groups, substrate structure, the nature of the base, and the solvent. Both mechanisms will occur in the presence of a good leaving group. Examples of good leaving groups include I- and Br-, where a poor leaving group includes F- and OH-. An E2 reaction works best with a secondary or tertiary carbon because primary carbons have more competition for SN2 reactions. Additionally, the E2 pathway occurs in one step and is referred to as a bimolecular concerted reaction. The concentration of substrate and the concentration of the base are important in determining the rate of an E2 reaction. An E1 reaction works best with a primary or secondary carbon. E1 rates are determined by the concentration of substrate and are not affected by the concentration of the base. The rate determining step is the intermediate step in which a carbocation is formed. The leaving group substrate bond is broken during the rate determining step. If the leaving group involved in an elimination reaction is a water molecule, the reaction will be a
References: Organic Lab Lecture Ericka Huston, Chong Liu. CHEM 0330 Organic Chemistry I Laboratory Manual Padias, Anne B. Making the Connections, A How-To Guide for Organic Chemistry Lab Techniques. Second ed.