Alcohols: Classification, Properties, Reactions, and Oxidation

Alcohols

– contain Hydroxyl group (OH) – suffix ol or hydroxy if a higher priority group is present- Diols contain two hydroxyl groups. * Geminal: 2 Hydroxyl groups on the same carbon* Vicinal: on adjacent carbons

1. What are alcohols?

Alcohols are organic compounds that contain one or more hydroxyl (-OH) groups attached to a carbon atom. They are a type of functional group in organic chemistry and have the general formula R-OH, where R represents an alkyl group or any other organic group.

2. How are alcohols classified?

Alcohols can be classified based on the number of -OH groups attached to the carbon atom. They can be monohydric, dihydric, or trihydric alcohols. Monohydric alcohols contain only one -OH group, dihydric alcohols have two -OH groups, and trihydric alcohols have three -OH groups.

Alcohols can also be divided based on the type of alkyl or organic group attached to the carbon atom. Examples include methyl alcohol, ethyl alcohol, and benzyl alcohol, among others.

3. What are some physical properties of alcohols?

Alcohols have higher boiling points than comparable hydrocarbons due to hydrogen bonding between the -OH groups. They are generally soluble in water and form hydrogen bonds with water molecules. As the size and complexity of the alcohol molecule increase, solubility in water decreases. Alcohols have a characteristic odor and can be used as solvents, antiseptics, and fuels.

4. What is the reaction between alcohols and sodium?

Alcohols can react with sodium metal in a displacement reaction to form an alkoxide salt and hydrogen gas. The alkoxide salt is formed when the -OH group of the alcohol is replaced by a negatively charged alkoxide -OR group.

For example, if methanol is reacted with sodium:

2 CH3OH + 2 Na → 2 CH3ONa + H2

This reaction can be used to prepare alkoxides, which are useful in many organic reactions.

5. How are alcohols oxidized?

Alcohols can undergo oxidation to form carbonyl compounds such as aldehydes and ketones. Oxidation occurs when the -OH group in the alcohol is converted into a carbonyl group (-C=O) while still attached to the carbon atom. Further oxidation can convert the carbonyl group into a carboxylic acid.

The oxidation of alcohols can be carried out using various oxidizing agents, including potassium permanganate, chromium (VI) oxide, and sodium dichromate. The specific oxidizing agent used depends on the oxidation state of the alcohol and the intended product. For example, primary alcohols are oxidized to aldehydes using pyridinium chlorochromate (PCC), while strong oxidants like potassium permanganate can oxidize primary alcohols all the way to carboxylic acids.

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