Naming Carboxylic Acids - Organic Chemistry IUPAC Naming by Leah4sci

Summary

This video tutorial explains how to name carboxylic acids using IUPAC rules. It covers the basic structure of a carboxylic acid and how to identify and number the parent chain. The video also discusses naming with multiple substituents, handling multiple carboxyl groups, and differentiating between aldehydes and ketones. Examples are provided to illustrate the process, and tips for organic chemistry success are shared.

Takeaways

• 📘 Carboxylic acids are identified by the carboxyl functional group, consisting of a carbonyl (C=O) and hydroxyl (OH) group.
• 🧪 Carboxylic acids are terminal functional groups and always receive the highest priority in IUPAC naming, with the carboxyl carbon assigned as carbon number 1.
• 🧩 The general formula for a carboxyl group can be written as R-COOH, where 'R' represents the remaining molecule.
• ✏️ To name a carboxylic acid, follow IUPAC naming rules and add the suffix '-oic acid' to the parent chain name, dropping the 'e' when appropriate.
• 🔢 Multiple substituents are named with their positions indicated by numbers, and substituents are listed in alphabetical order in the final name.
• 🔄 When a molecule contains more than one carboxyl group, each is assumed to be terminal, and the name is modified to include 'dioic acid' without needing to number the groups.
• 🔬 For cyclic compounds, the ring is named with the suffix '-carboxylic acid' attached to the parent chain name, indicating the presence of a carboxyl group on the ring.
• ⚖️ If both a carboxyl and a carbonyl (ketone or aldehyde) are present, the carboxyl group takes precedence in numbering, and the carbonyl gets the prefix 'oxo-' in the name.
• 📊 Aldehydes and ketones are distinguished by their position in the chain: aldehydes at the end, ketones in the middle.
• 📚 More advanced naming concepts include recognizing derivatives of carboxylic acids such as esters and amines, which will be discussed in future videos.

Q & A

What is the basic structure of a carboxylic acid?

A carboxylic acid is characterized by a carbonyl carbon double-bonded to an oxygen and a single bond to a hydroxyl group (OH). It can be represented as RCOOH or RCO2H, where R represents the rest of the molecule or a carbon chain.

How does the carboxyl functional group differ from an alcohol or an aldehyde?

The carboxyl group is distinguished by the presence of a carbonyl (C=O) bonded to an oxygen which is also bonded to a hydrogen (OH). In contrast, an alcohol has a hydroxyl group (OH) without a carbonyl, and an aldehyde has a carbonyl bonded to a hydrogen instead of an oxygen-hydrogen group.

What is the IUPAC naming rule for carboxylic acids?

In IUPAC nomenclature, carboxylic acids are named by adding the suffix '-oic acid' to the name of the longest carbon chain that includes the carboxyl group, which is always considered as carbon number 1.

Why is the number 1 often omitted in the naming of carboxylic acids?

The number 1 is understood to be the position of the carboxyl group in carboxylic acids, so it does not need to be explicitly stated in the name.

How do you name a carboxylic acid with substituents?

You identify and number the parent chain, assign the carboxyl group the number 1, and then list substituents in alphabetical order as prefixes before the parent chain name and the '-oic acid' suffix.

What happens when there are multiple carboxylic acid groups in a molecule?

When there is more than one carboxyl group, they are both considered terminal and given the highest priority, resulting in the suffix '-dioic acid'. The numbers do not need to be included in the name.

Can you provide an example of naming a carboxylic acid with a ring?

A carboxylic acid attached to a ring is named by first identifying the ring as you would normally, then adding the '-oic acid' suffix. For example, a five-membered ring would be named 'cyclopentane-oic acid'.

What is the difference between naming a ketone and an aldehyde in a carboxylic acid derivative?

In carboxylic acid derivatives, a ketone or aldehyde is demoted to an axial substituent and given the prefix 'oxo'. The difference between the two is determined by their position on the parent chain; an aldehyde is at the end (number 1), and a ketone is in the middle.

How do you interpret a complex name with two 'oxo' prefixes in a carboxylic acid?

When a name has two 'oxo' prefixes, it indicates the presence of two carbonyl groups. The position of these groups on the parent chain determines whether they are aldehydes or ketones.

What is the significance of the term 'dioic acid' in IUPAC nomenclature?

The term 'dioic acid' in IUPAC nomenclature signifies that there are two carboxylic acid groups present in the molecule.

How does the presence of a carboxylic acid affect the numbering of the parent chain?

The presence of a carboxylic acid affects the numbering of the parent chain by making the carbonyl carbon the first carbon, regardless of the total length of the chain.