Reactions of Alcohols
Alcohols are commonly used compounds in organic chemistry. They are one of the most commonly occurring organic compounds, easily produced on a large scale by fermentation of sugars and easily converted to other compounds. Chemically speaking they are comparable to water, where one of the hydrogens is replaced by a carbon chain. Therefore alcohols also have an acidity comparable to water (pKa ≈ 16 at room temperature).
The most common alcohol is ethanol (also known as ethyl alcohol or just "alcohol"). This is the alcohol that is present in alcoholic drinks, pharmaceuticals and desinfectants. Another well known alcohol is methanol (also known as methyl alcohol), which is used in the synthesis of formaldehyde and in anti-freeze solutions. Both alcohols are also used as a solvent and in fuels. Methanol is very toxic compared to ethanol and in case of intoxication ethanol can be used as an antidote.
Types of reactions
- Oxidation of alcohols
- Reactions of alcohols with active metals
- Substitution reactions of alcohols
- Dehydration of alcohols
Summary
Which reactions can happen to alcohols?
Alcohols can undergo oxidation reactions to form ketones, aldehydes or carboxylic acids; they react with alkalimetals to form strongly basic salts; after "activation" of the OH-group they can undergo nucleophilic substitution reactions and finally they can be dehydrated (elimination of water) using heat in the presence of a catalyst.
More informationWhat happens when an alcohol is oxidized?
An alcohol is, depending on it's structure, oxidized to a ketone or a carboxylic acid due to a strong oxidizing agent such as chromic acid. A weaker oxidizing agent can convert an alcohol into an aldehyde.
More informationHow do alcohols undergo substitution reactions?
Alcohols first need to be activated before nucleophilic substitution is possible. This can be done by protonating the alcohol, letting it react with a phosphorus halide or by converting the alcohol to a sulfonate ester. De created compound can then be easily attacked by a nucleophile.
More informationWhat happens when an alcohol is dehydrated?
Upon dehydration of an alcohol a molecule of water is lost and the most stable alkene forms. Depending on the structure of the alcohol, other reactions may compete with the dehydration which causes by-products to form (such as ethers).
More informationWhat is an alkoxide?
An alkoxide is a strongly alkaline salt that is formed from the reaction of an alcohol with a piece of solid sodium. It is basically a deprotonated alcohol. The alkoxide can be used for further reactions or to create strongly alkaline solutions. The reaction also produces hydrogen gas.
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