14.2 Reactions of alcohols Flashcards by Maya Hennig

What type of reaction is the combustion of alcohols?

Exothermic, releasing large quantity of heat

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As the number of carbons in an alcohol increases what happens to combustion?

There will be an increased quantity of heat released per mole

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What are the products of the combustion of alcohols?

CO2, H2O

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What is the equation for the combustion of ethanol?

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What is the symbol used for an oxidising agent?

[O]

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What is the formula of potassium dichromate?

K2Cr2O7

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What is the suffix for an aldehyde?

—al

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What is the suffix for a ketone?

—one

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What alcohols undergo oxidation?

Primary, secondary

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What colour change is observed for K2Cr2O7 if oxidation occurs?

Orange to green

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What can primary alcohol be oxidised to?

Aldehydes or carboxylic acids

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What can secondary alcohols be oxidised to?

ketones

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What is the oxidising agent used for the oxidation of primary and secondary alcohols?

Acidified potassium dichromate (K2Cr2O7) with dilute sulfuric acid (H2SO4)

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What is the equation for the oxidation of dichromate ions?

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What is the equation for the oxidation of butane-1-ol to an aldehyde?

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What are the reagents and conditions for the oxidation of primary alcohols to aldehydes?

K2Cr2O7/ dilute H2SO4, distill

Why is distillation used (gentle heating) for oxidation of primary alcohols to aldehydes?

To ensure that an aldehyde is formed rather than a carboxylic acid. Prevents any further reaction with the oxidising agent

What are the reagents and conditions for the oxidation of primary alcohols to carboxylic acids?

K2Cr2O7/ dilute H2SO4, heated strongly under reflux

What is the equation for the oxidation of butan-1-ol to a carboxylic acid?

Why is excess oxidising agent used for oxidation of primary alcohols to carboxylic acids?

To ensure all the alcohol is oxidised

Why the oxidation of primary alcohols to carboxylic acids heated strongly?

To ensure that al the aldehyde originally made oxidises to form carboxylic acids

What is the products for the oxidation of primary alcohols under reflux?

Carboxylic acid, water

What is the products for the oxidation of primary alcohols under distillation?

Aldehyde, water

What is the products for the oxidation of secondary alcohols under reflux?

Ketone, water

What are the reagents and conditions for the oxidation of secondary alcohols to ketones?

K2Cr2O7/ dilute H2SO4, heated under reflux

What is the equation for the oxidation of propan-2-ol?

Why can ketones not be further oxidises?

To add the OH needed for a carboxylic acid, you would need to break the C-C bond which requires too much energy

Why do tertiary alcohols not undergo oxidation?

The C-C bond would have to be broken which requires too much energy. K2Cr2O7 would remain orange

What is a dehydration reaction?

An elimination reaction in which water is removed from a saturated molecule to form an unsaturated molecule

What are the conditions and reagents for the dehydration of an alcohol?

Alcohol heated under reflux, acid catalyst (concentrated H2SO4 or concentrated H3PO4)

What are the produces for dehydration of alcohols?

Alkene, H20

What type of reaction is a dehydration reaction?

Elimination

What is the equation for the dehydration of cyclohexanol?

What type of reaction is the reaction of alcohols to form haloalkanes?

Substitution

What are the regents and conditions for the reaction of alcohols to form haloalkanes?

-Heated under reflux with sulfiric acid and a sodium halide

What are the two steps for the substitution reaction of propan-2-ol?

What is the overall equation for the substitution reaction of propane-2-ol?

What are the predicts of the substitution reaction of alcohols?

Haloalkane, and water