Dehydration of Methyycylcohexanols and the Evelyn Effect

Dehydration of Methyycylcohexanols and the Evelyn Effect

Purpose: dehydration of 2-methylcyclohexanol by heating the alcohols in the presence of phosphoric acid. Both alcohols will be mixtures of cis and trans isomers, so either one or both may exhibit and Evelyn Effect.

Materials: stirrer, heating device, reaction vessel, stir bar, Erlenmeyer flask, drying agent, funnel, fluted paper, bench top centrifuge, two centrifuge tubes, Pasteur pipet, flat-bladed micro spatula, gas chromatograph and r4corder, 10ml microsyringe, screw-cap vial containing sample, lab tissues, syringe washing solvent.

REACTION

-Weigh 15mmol of 2-methylcyclohexanol or 4-methylcyclohexanol (cis-trans mixtures) into a 50 ml round bottom flask.

-Mix in 5.0 ml of 85% phosphoric acid and drop in a stir bar or boiling chips.

-Clamp flask to a ring stand over heat source and assemble apparatus for simple distillation. Use 10 ml graduated cylinder for receiving.

-Have ready 2 clean, numbered 25ml screw-cap centrifuge tube and cap the tube.

-Star stirrer and heat reactants so It distills at a rate of 1 drop per second or less.

-Record vapor temp after distillation begins.

-Monitor the volume of the alkene (top layer). When it 8 ml, quickly pur into the first centrifuge yube, cap the tube, replace the graduated receiver, and continue distilling.

-After the alkene volume reaches about 6ml, monitor the still head temperature continually.

-Lower heat source and turn off when you observe a marked temp drop at the still head, which may be accompanied by foaming and dense white fumes in the reaction flask.

-Pour distillate