Questions and Answers
What is the classification of amines?
How do you name primary amines?
Count the length of the carbon chain, identify the number of the carbon to which nitrogen is attached, and add '-amine' to the end, e.g., ethan-1-amine.
What is the naming convention for secondary and tertiary amines?
Count the length of the longest carbon chain, identify the carbon number to which nitrogen is attached, add '-amine', and prefix 'N-' to each R group.
What role do amines play as bases?
Signup and view all the answers
What does the strength of an amine base depend on?
Signup and view all the answers
What is the order of strength of amine bases?
Signup and view all the answers
What happens when ammonia reacts with water?
Signup and view all the answers
What characterizes primary aliphatic amines?
Signup and view all the answers
Why are primary aliphatic amines stronger bases than ammonia?
Signup and view all the answers
What are primary aromatic amines?
Signup and view all the answers
Why are primary aromatic amines weaker bases than ammonia?
Signup and view all the answers
What reactants are involved in making primary amines?
Signup and view all the answers
Why is excess ammonia used when making primary amines?
Signup and view all the answers
What reaction occurs to make secondary amines from primary amines?
Signup and view all the answers
How are tertiary amines made from secondary amines?
Signup and view all the answers
What is formed when quaternary ammonium salts are made from tertiary amines?
Signup and view all the answers
What are some uses of quaternary ammonium salts?
Signup and view all the answers
How can primary amines be made from nitriles?
Signup and view all the answers
What is the reaction for making phenyl amines from nitro compounds?
Signup and view all the answers
How can nitrobenzene be converted to phenyl amine?
Signup and view all the answers
Study Notes
Classification of Amines
- Amines are classified into three types:
- Primary (one R group) - NRH2
- Secondary (two R groups) - NR2H
- Tertiary (three R groups) - NR3
Naming Primary Amines
- Count the length of the carbon chain for naming.
- Identify the carbon to which the nitrogen is attached.
- Append '-amine' to the name, e.g., ethan-1-amine.
Naming Secondary and Tertiary Amines
- Determine the longest carbon chain length when naming.
- Identify the carbon to which nitrogen is connected.
- Add '-amine' to the end of the name.
- Specify R groups attached to nitrogen with 'N-' prefix, e.g., N-methyl N-ethyl propan-2-amine.
Amines as Bases
- Amines act as Bronsted-Lowry bases because they can accept protons.
- Classified as Lewis bases due to the presence of a lone pair of electrons on nitrogen, allowing them to form coordinate bonds with electron-deficient species.
Strength of Amine Bases
- The strength of an amine base depends on the availability of the lone pair of electrons on nitrogen; increased availability leads to stronger bases.
Order of Strength of Amine Bases
- Primary aliphatic amines are the strongest.
- Ammonia has moderate base strength.
- Primary aromatic amines are the weakest.
Ammonia and Basic Solutions
- Ammonia (NH3) reacts with water yielding NH4+ and OH-, resulting in a basic solution.
Primary Aliphatic Amines
- Defined as amines without a benzene group attached to nitrogen.
- React with water to form NH3R and OH-.
Strength Comparison: Primary Aliphatic Amines vs. Ammonia
- Primary aliphatic amines are stronger bases than ammonia due to their electron-releasing alkyl groups, which increase electron density on nitrogen.
Weakness of Primary Aromatic Amines
- Primary aromatic amines are weaker bases than ammonia because the benzene ring is electron-withdrawing, making the nitrogen's lone pair less available for protonation.
Synthesizing Primary Amines
- Primary amines are produced via nucleophilic substitution, reacting haloalkanes with ammonia: RBr + 2NH3 → RNH2 + NH4+ + Br-.
Excess Ammonia in Synthesis
- Using excess ammonia ensures that haloalkanes react with ammonia rather than the formed primary amine, preventing secondary and tertiary amine production.
Making Secondary Amines
- Secondary amines are synthesized by reacting primary amines with haloalkanes: RBr + NH2R → NHR2 + HBr.
Making Tertiary Amines
- Tertiary amines are formed by reacting secondary amines with haloalkanes: RBr + NHR2 → NR3 + HBr.
Quaternary Ammonium Salts Production
- Created by reacting tertiary amines with haloalkanes: RBr + NR3 → +NR4 + HBr.
Uses of Quaternary Ammonium Salts
- Function as cationic surfactants, bonding to non-polar substances and aiding in fabric conditioners and shampoos to reduce surface tension.
Reducing Nitriles to Primary Amines
- Reaction involves RCN with reducing agents like H2 (with nickel catalyst) or LiAlH4, resulting in primary amines: RCN + 4[H] → RCH2NH2.
Making Phenyl Amines from Nitro Compounds
- Nitro compounds (RNO2) can be reduced to phenyl amines via hydrogenation with H2 (nickel catalyst) or granulated tin and HCl: RNO2 + 6[H] → RNH2 + 2H2O.
Textile Dyes from Nitro Compounds
- Nitrobenzene is reduced to phenylamine, which can form diazonium salts that react with phenylamine to yield colored azo dyes, acting as coupling agents for various colors.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge on the classification and naming of amines with this detailed quiz. You'll learn about primary, secondary, and tertiary amines, as well as the rules for naming them correctly. Perfect for organic chemistry students.
