Chemistry: Week 5 Pt 2 - Functional Groups with Oxygen and Nitrogen

Functional Groups: Adding Oxygen and Nitrogen to Hydrocarbons

Introduction

• Functional groups containing oxygen and nitrogen are added to hydrocarbon chains.
• Major elements in the human body: carbon, hydrogen, oxygen, and nitrogen.
• Most compounds in the body are carbon-based. Functional groups added will be either oxygens or nitrogens.
• Focus on single oxygens first.

Single Oxygen Functional Groups

Alcohols and Aldehydes

• The oxygen is always at the end of the carbon chain.
• No other carbons to the right.

Ethers and Ketones

• Oxygen is in the middle of the carbon chain.
• Carbon-oxygen-carbon structure for ethers.
• Carbon-oxygen structure for ketones.
• Carbons on both sides of the oxygens; not at the end.

Alcohols

• Functional group: Alcohol.
• Attached group: Hydroxyl group (-OH).
• Made by removing a hydrogen from a hydrocarbon chain and adding an oxygen and a hydrogen to that oxygen.

Condensed Structure

• Example: CH3CH2OH

Naming Alcohols

1. Count the number of carbons.
2. Write down the prefix for that many carbons (e.g., three carbons = "prope").
3. Add "ane" to the end for the full alkane name (e.g., propane).
4. Remove the final "e".
5. Add "ol" for an alcohol (e.g., propanol).

Aldehydes

• Contain a carbonyl group (carbon double-bonded to an oxygen).
• Written as CHO, found at the end of a carbon chain.

Condensed Structural Formula

• Example: CH3CHO
• Ending is HO, not OH (alcohol).

Naming Aldehydes

1. Count the number of carbons.
2. Write down the prefix for that many carbons (e.g., two carbons = "eth").
3. Add "ane" for the alkane name (e.g., ethane).
4. Remove the final "e".
5. Add "al" for an aldehyde (e.g., ethanal).

• Different endings: "al" for an aldehyde, "ol" for an alcohol.

Ketones

• Also contain a carbonyl group.
• The carbonyl is in the middle of the chain (carbons on both sides).

Condensed Structural Formula

• Example: CH3COCH3

Naming Ketones

1. Count the number of carbons.
2. Write down the prefix for that many carbons (e.g., four carbons = "but-").
3. Add "ane" to make the alkane name (e.g., butane).
4. Remove the final "e".
5. Add the ending "-one" for a ketone (e.g., butanone).

Ethers

• Result from condensation reactions.
• Linking two compounds together and releasing a water molecule ($H_2O$).
• Two separate alcohols remove $H_2O$ and connect via oxygen.
• Oxygen in the middle of the chain (carbons to the left and right).
• Written as COC.

Condensed Structural Formula

• Example: $CH<em>3CH</em>2OCH<em>2CH</em>2CH<em>2CH</em>3$

Naming Ethers

1. Count the number of carbons to the left of the oxygen.
2. Write down the prefix for that many carbons and add the "-yl" ending (e.g., two carbons = "ethyl").
3. Do the same for the carbons to the right.
4. Put them in alphabetical order.
5. Add the word "ether" (e.g., butyl ethyl ether).

Functional Groups with Two Oxygens or One Nitrogen

Two Oxygens

• Carboxylic acids: two oxygens and a hydrogen at the end of a chain.
• Esters: two oxygens in the middle of a chain.

One Nitrogen

• Amines: NH2, typically at the end of a chain.
• Amides: carbon and nitrogen next to one another (carbon, oxygen, and nitrogen).

Carboxylic Acids

• Contain both a carbonyl and an alcohol group.
• Result from an oxidation reaction (gain of oxygens).
• Written as COOH at the end of a chain.

Condensed Structural Formula

• Example: $CH_3COOH$

Naming Carboxylic Acids

1. Count the number of carbons.
2. Write down the prefix for that many carbons (e.g., two carbons = "eth").
3. Add "ane" for the alkane ending (e.g., ethane).
4. Remove the final "e".
5. Add "oic acid" (e.g., ethanoic acid).

Esters

• Result from a condensation reaction between a carboxylic acid and an alcohol.
• Remove $H_2O$ and attach the oxygen to the carbon.
• Written as COOC (in the middle of the chain).
• Found in flavorings and scents.

Condensed Structural Formula

• Example: $CH<em>3COOCH</em>2CH<em>2CH</em>2CH_3$

Naming Esters

1. Find the single oxygen and count the number of carbons to the right of it.
2. Write down the prefix and add the "yl" ending (e.g., one carbon = "methyl").
3. Count the number of carbons to the left of the single oxygen (including the carbon in the carbonyl group).
4. Write down the prefix and add the alkane ending.
5. Remove the final "e" and add "oate" (e.g., methylbutanoate).

Amines

• Derived from ammonia.
• Found at the end of chains.
• NH3 is the functional group.
• Found on every amino acid.

Condensed Structural Formula

• Example: $CH<em>3NH</em>2$

Naming Amines

1. Count the number of carbons.
2. Write down the prefix and add the "-yl" ending (e.g., one carbon = "methyl").
3. Add the word "amine" (e.g., methylamine).

Amides

• Found when linking together long chains of amino acids.
• Condensation reaction between an amine group and a carboxylic acid group.
• CON is the functional group (nitrogen next to the oxygen).

Condensed Structural Formula

• Example: $NH<em>2CH</em>2CONCH<em>2CH</em>2COH$

Naming Amides

1. Count the number of carbons.
2. Write down the prefix and add "ane" for propane.
3. Remove the final "e".
4. Add "amide" at the end (e.g., propanamide).