Experiment 7: Dehydration of Cyclohexanol

Positive Baeyer Test

purple ----> dark brown manganese dioxide precipitate

What is a Bromine test?

tests for the presence of unsaturation, phenols, and anilines.

What is a Baeyer test?

tests for unsaturation for determining the presence of carbon-carbon double-bonded compounds.

Bromine Test forms what compound?

trans-1,2-dibromocyclohexane

Baeyer test (potassium permanganate) tests for

unsaturation

____ is eliminated to form a _______ ______ ______bond

water; carbon-carbon pi

The good questions start here and below

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3 Factors of Organic Rxns?

-each reactant dissolved in a solvent -one solution is added slowly to another -extothermic

Positive Bromine test

dark orange -----> clear

What apparatus is used in Dehydration of Cyclohexanol?

Fractional Distillation

How to increase sped of rxn if it is slow?

Heat it

How many moles of Water does it take to distill 2.2 moles of cyclohexanol?

1 mole of water!

What 2 factors promote elimination and increase total product (cyclohexene?)

1. Use acid with a poor nucleophile rxn. 2. High rxn temperature.

3 steps of acid-catalyzed dehydration?

1.protonation 2.dehydration 3.deprotonation

Fractional distillation apparatus

17 items used

What temp must the experiment be kept under to avoid distilling cyclohexanol as an azeotrope?

90 degrees

What happens during the Baeyer test?

A cyclic manganate ester is formed and then hydrolyzed into cis-1,2-cyclohexanediol

In what direction is the product being removed?

A foward direction makes the reaction occurs.

What do organic reactions usually have?

Competing pathways; yield more than one product

What is the Alcohol being dehydrated?

Cyclohexanol

What is the Alkene being produced?

Cyclohexene

Objective of Dehydration of Cyclohexanol

Dehydrate alcohol to produce alkenes.

What type of reaction is this lab?

Elimination

What principle will shift the rxn towards the product?

Le Chatelier's principle

Why is proton acid catalysis required?

OH is a poor leaving group

What does fractional distillation even do?

Separates a mixture into its component parts. Chemical compounds are separated by heating them to a temperature at which one or more fractions of the mixture will vaporize.

Wtf is an azeotrope?

a mixture of two liquids which has a constant boiling point and composition throughout distillation.