Topic: Amines

Target group

High school / technical school student

Core curriculum

New core curriculum:

High school and technical high school. Chemistry – basic level:

XVIII. Nitrogen‑containing organic compounds. Pupil:

1) describes the structure and classification of amines;
2) compares the structure of ammonia and amines; draws electronic patterns of ammonia molecules and methylamine;
3) indicates differences and similarities in the structure of methylamine and phenylamine (aniline);
4) compares and explains the reason for the basic properties of ammonia and amines; writes appropriate reaction equations;
5) write equations for the reaction of methylamine with water and with hydrochloric acid;

High school and technical high school. Chemistry – extended level:

XVIII. Nitrogen‑containing organic compounds. Pupil:

1) describes the structure of amines; indicates the formulas of primary, secondary and tertiary amines;
2) compares the structure of ammonia and amines; draws electronic patterns of ammonia and amine molecules (e.g. methylamine);
3) indicates similarities and differences in the structure of aliphatic amines (e.g. methylamines) and amines aromatic (e.g. phenylamine (aniline));
4) compares and explains the reason for the basic properties of ammonia and amines; writes appropriate reaction equations;
5) writes reaction equations for obtaining aliphatic amines (e.g. in the process of alkylation of ammonia) and aromatic amines (e.g., preparation of aniline as a result of a nitrobenzene reduction reaction);
6) describes the chemical properties of amines based on the reaction: with water, with inorganic acids (e.g. with hydrochloric acid) and carboxylic acids; writes appropriate reaction equations.

Old core curriculum:

High school and technical high school. Chemistry – basic level:

XVIII. Organic compounds containing nitrogen. Pupil:

1) describes the construction and classification of amines;
2) compares the construction of ammonia and amines; draws electron formulas of ammonia and methylamine molecules;
3) indicates differences and similarities in the structure of methylamine and phenylamine (aniline);
4) compares and explains the reason for the basic properties of ammonia and amines; writes relevant equations of reaction.

General aim of education

The student describes the structure and properties of methylamine

Key competences

• communication in the mother tongue;

• communication in foreign languages;

• mathematical competence and basic competences in science and technology;

• learning to learn.

Criteria for success
The student will learn:

• what amines are;

• describe the structure and properties of compounds containing nitrogen – on the example of methylamine (amine);

• write down the methylamine and ethylamine formulas;

• name application of amines.

Methods/techniques

• expository

  • talk.

• activating

  • discussion.

• exposing

  • film.

• programmed

  • with computer;

  • with e‑textbook.

• practical

  • exercices concerned.

Forms of work

• individual activity;

• activity in pairs;

• activity in groups;

• collective activity.

Teaching aids

• e‑textbook;

• notebook and crayons/felt‑tip pens;

• interactive whiteboard, tablets/computers;

• sheets of gray paper;

• colored markers;

• sets for building particle models.

Lesson plan overview

Introduction

1. The teacher hands out Methodology Guide or green, yellow and red sheets of paper to the students to be used during the work based on a traffic light technique. He presents the aims of the lesson in the student's language on a multimedia presentation and discusses the criteria of success (aims of the lesson and success criteria can be send to students via e‑mail or posted on Facebook, so that students will be able to manage their portfolio).

2. The teacher together with the students determines the topic – based on the previously presented lesson aims – and then writes it on the interactive whiteboard/blackboard. Students write the topic in the notebook.

Realization

1. Students get acquainted with the content of the abstract and define the concept of amines. Then, working in pairs, based on available sources, they look for information on the division of amines due to the nature of the substituents on the nitrogen atom and due to the orderliness. The results of their work are presented graphically (in the form of a diagram). The teacher makes sure that the task have been correctly completed and gives feedback.

2. The teacher presents the general formula of amines and discusses their construction. Then he gives - as an example of these compounds - methylamine and displays the animation „Creating a methylamine formula”.

3. Students are selected into groups. They receive construction kits and asks for building a model of methylamine molecule from ball‑and‑ball models. It checks the correctness of the task. Next, he writes on the board the formulas of the total, semi‑structural and structural amines with two carbon atoms. Explains the rules for the creation of amine names on the example of methylamine and ethylamine. Students write formulas of these relationships in notebooks.

4. Students, working in the same groups, develop on the basis of various sources of knowledge the issue of properties and uses of methylamine. They create posters on large sheets of paper, illustrating the collected information. After completion of activities, group leaders present the effects of teamwork.

5. Students perform an interactive exercise. The teacher discusses the right solution with them.

6. Students arrange crosswords on issues learned during the lesson. They exchange them in pairs and solve them.

Summary

1. The teacher asks a willing student to summarize the lesson from his point of view. He asks other students if they would like to add anything to their colleague's statements.

Homework

1. Carry out task number nr 2.1.

The following terms and recordings will be used during this lesson

Terms

Texts and recordings

Amines

The unpleasant smell of fish is caused by the presence of a compound containing nitrogen atoms in its molecules. This substance is methylamine, belonging to the group of amines.

Amines can be treated as derivatives of ammonia, in which at least one hydrogen atom has been replaced with a hydrocarbon group.

Genera formula of amines:

where:

$\text{R}$ – a hydrocarbon group,
${\text{– NH}}_{\text{2}}$ – amino group (functional group).
The amine compound is methylamine of the formula ${\text{CH}}_{\text{3}}\text{–}{\text{NH}}_{\text{2}}$.

An example of an amine containing two carbon atoms is ethylamine of the formula ${\text{CH}}_{\text{3}}{\text{– CH}}_{\text{2}}{\text{– NH}}_{\text{2}}$. Ethylamine is a colourless liquid (at a temperature less than 16.6°C) with sharp, ammonia odour. It is a natural component of the urine.

With the increase in the number of carbon atoms in the molecules of amines, their properties change – the boiling point increases and the solubility in water decreases. Amines are mostly toxic compounds. These occur in small amounts in many plants. These are also secreted during the decomposition of fish. Amines are very important because these are used to receive medicines and also found application in the production of synthetic fibres and dyes.

Aniline is the prototypical aromatic amine consisting of a phenyl group attached to an amino group. Its main use is in the manufacture of precursors to polyurethane and other industrial chemicals. Like most volatile amines, it has the odor of rotten fish. It ignites readily, burning with a smoky flame characteristic of aromatic compounds.

Degree of amine substitution is determined in the same way as the degree of carbon atoms. It is equal to the number of hydrogen atoms on the nitrogen atom replaced with carbon atoms. Amines are divided into primary (HIndeks dolny 2₂NR), secondary (HNRIndeks dolny 2₂), tertiary (NRIndeks dolny 3₃). It is also possible to have four organic substituents on the nitrogen. These species are not amines but are quaternary ammonium cations and have a charged nitrogen center. Quaternary ammonium salts exist with many kinds of anions. Amines with high molecular weights, usually tertiary and higher, are also called macromolecular amines.

The basic amine naming system is the use of the „amine” core and the names of the hydrocarbon substituents listed alphabetically in the prefix.
In the case of amines containing more amino groups, the name is derived from the parent hydrocarbon and after the linker „o”, the di‑tri‑etc. tip is added.
However, when an amine contains yet another functional group, the presence of an amino group is indicated by the prefix „amino” with the appropriate locant.
Sometimes in the names of secondary and tertiary amines, to avoid ambiguity, the names of the substituents associated with nitrogen are preceded by the inclined letter N.
For aromatic and heterocyclic amines, special names are used instead. See the examples below.

• Amines and amino acids are organic compounds containing nitrogen atoms in their molecules.

• The properties of amines change with increasing number of carbon atoms in the molecule.