Municipal budgetary educational institution secondary school No. 2

Development of a lesson on the topic.

Classification of organic compounds

9th grade

Teacher: Nosova E.V.

Goals lesson:

Educational.

To familiarize students with the main classes of organic compounds,

features of their composition and nomenclature.

Give the concepts: homological series, substances - homologues, characteristics characteristic of substances of the same homologous series.

Educational.

Dialectical – materialistic, aesthetic, international.

Developmental.

Development of knowledge about the diversity of substances in nature, structural features

organic substances, the ability to write down molecular and structural

formulas of compounds. Development of cognitive interest in the subject,communicative qualities of students.

Equipment: textbook, presentation for the lesson, ball-and-stick models of methane, ethane, ethene, ethyne.

Teaching methods: partially search; explanatory - illustrative, visual, verbal

Lesson type . Learning new material

The lesson is designed for 9th grade students with high and average levels of motivation.

During the classes

I. Updating knowledge

1. Frontal conversation on issues from the previous lesson.

1) What substances are called organic?

2) Define organic chemistry.

3) Basic principles of the theory of the structure of organic compounds by A. M. Butlerov

4) What is meant by chemical structure?

II. Learning new material.

Recording the lesson topic"Classification of organic compounds"

Lesson Objectives .

Study the main classes of organic compounds, features of their composition and nomenclature.

Find out the concepts: homologous series, substances - homologues, characteristics characteristic of substances of the same homologous series.

Problem

Currently, there are more than 25 million different substances. Some of them are found in nature, others are obtained synthetically.

Why are there so many more organic substances than inorganic substances? (slide)

The classification of organic compounds is based on the theory of structure of A.M. Butlerov. The main part of the molecules consists of carbon atoms directly connected to each other and forming chains.

1Study of saturated hydrocarbons – alkanes; other names for alkanes: saturated, saturated.

Recording the molecular formulas of the first ten representatives (children write using a textbook (O.S. Gabrielyan, p. 203, table 9)) (see slide)

B) recording the structural formulas of individual representatives of alkanes and their names, table 9 of the textbook. (Slide),

Reasons for the name: C1-C4 are historical, subsequent members of the homologous series are formed from the Greek series, which indicate the number of carbon atoms, with the addition of a suffix.

The international or Geneva nomenclature is considered the main one; its basic principles were adopted at the international congress of chemists in Geneva in 1892.

c) Derivation and recording of the general formula of alkanes, the presence of single bonds in molecules, a common suffix in the names of substances

INconclusion. A series of substances arranged in increasing order of relative molecular weights, similar in structure and properties, but differing from each other in composition by one or more groups - CH2-, is called a homologous series.

Substances of this series are called homologs, (- CH2) – homological difference

Thus, alkanes are hydrocarbons that have only single bonds, the general formula WITH nH 2 n +2 , in the name the suffix “an”

2 Study of radicals .

A) Demonstration of a radical on a model, formulation of the concept of a radical p. 200 (a particle having an unpaired electron or free valence),

Distinctive features in comparison with alkanes, we make notes parallel to the homologous series of alkanes.

Conclusion. General formula of radicals, free valency. WITH nH 2 n +1

3 Unsaturated organic compounds - alkenes .

A) Task. Using the molecular and structural formulas of ethene, compose a homologous series of alkenes parallel to alkanes (molecular and structural formulas). (work in pairs)

B) Name the first representatives of alkenes. Pay attention to the general and special features of alkanes and alkenes.

Children formulate a conclusion about alkenes.

Conclusion. Alkenes are hydrocarbons that have one double bond, the general formula WITH nH 2 n , in the name the suffix “en”

4 . Unsaturated organic compounds – alkadienes.

A) Task. Using the molecular and structural formulas of butadiene -1,3, compose a homologous series of alkadienes parallel to alkenes (molecular and structural formulas). (work in pairs)

B) Name the first representatives. Pay attention to the general and special aspects of alkanes and alkenes, alkadienes.

Children formulate a conclusion about alkadienes. (see slides)

Conclusion. Alkadienes are hydrocarbons that have two double bonds, the general formula WITH nH 2 n -2 , in the name the suffix “diene”

4. Unsaturated organic compounds – alkynes.

A ) Exercise. Using the molecular and structural formulas of ethyne, compose a homologous series of alkynes parallel to alkadienes (molecular and structural formulas). (Work in pairs)

B) Name the first representatives of alkynes. Pay attention to the general and special features of alkanes and alkenes.

Children formulate a conclusion about alkynes.

Conclusion. Alkynes are hydrocarbons that have one triple bond, the general formula WITH nH 2 n -2 , in the name the suffix “in”

5. Oxygen-containing organic compounds

A) saturated monohydric alcohols

Exercise. Using the molecular and structural formulas of ethanol, compose a homologous series of saturated monohydric alcohols. (Molecular and structural formulas). (Work in pairs)

Name the first representatives. Pay attention to the common features with alkanes and the group - OH.

Children formulate a conclusion about saturated monohydric alcohols. (see slides)

Conclusion. Alcohols are compounds in which a hydrocarbon radical is bonded to a hydroxyl group - OH. General formulaR -HE, in the name - the suffix “ol”

B) Aldehydes

Exercise. Using the molecular and structural formulas of methanal, compose a homologous series of aldehydes. (Molecular and structural formulas). (Work in pairs)

Name the first representatives. Compare with alkanes, alcohols

Conclusion. Aldehydes are compounds whose molecules have the group - C = O related to

H

hydrocarbon radical (except for the first representative), in the name - the suffix “al” R - C = O

N

c) Carboxylic acids

Exercise. Using the molecular and structural formula of methane acid, compose a homologous series of carboxylic acids. (molecular and structural formulas). (work in pairs)

Name the first representatives. Compare with alcohols

Conclusion: carboxylic acids - these are compounds whose molecules have a group,

- C = O

ABOUT H

associated with a hydrocarbon radical (except for the first representative). General formula R - C = O

ABOUT H

Groups of atoms that determine membership in a certain class of compounds and the most characteristic properties are called functional groups.

6. Esters .

Products of replacement of a hydrogen atom in the hydroxyl group of alcohols with a hydrocarbon radical

General formula R 1 - O - R 2

Conclusion from the lesson. (Formulated by students)

Thus, there are very different classes of organic compounds: limiting ones, with single bonds between carbon atoms, which are connected to the maximum possible number of hydrogen atoms, that is, saturated to the limit; classes of unsaturated hydrocarbons that contain double or triple carbons - carbon bonds and organic substances containing functional groups.

There are a large number of homological series that contain a large number of organic compounds; therefore, homological series of organic compounds is one of the reasons for their diversity. This phenomenon is possible due to the fact that the carbon atom is tetravalent and can form very different chain lengths of carbon atoms.

Specify the features of homologous series

III. Consolidation of knowledge.

1. We write in a notebooktitle "Organics in your hands"

We draw our palms in a notebook, number our fingers, write the name of the console, inside our hands there are tablets with three columns and fill them out.

2. Using the knowledge and “hands” acquired in the lesson, draw up structural formulas of substances of the studied homologous series that contain 5 carbon atoms and name them, highlight the functional groups. (Work in pairs) (pentane, pentene, pentadiene -1,3, pentine-1, pentanol, pentanal, pentanoic acid.)

3. Using the structural formulas of substances, the children determine whether they belong to a homologous series and name them.

4. Among the proposed substances, find homologues of methane, ethyne, ethyl alcohol, etc. (See textbook by N.E. Kuznetsova and others. Grade 9. Wide variety of tasks)

5.Questions.

What studied substances have you encountered in your life?

Why are alkanes called saturated - saturated?

Why are they called paraffins?

Why were other representatives of hydrocarbons called unsaturated??

Why are there so many more organic compounds than inorganic ones?

Assessing students' knowledge

IV. Bottom line.

Today in class we studied the homologous series of various classes of organic substances. Their characteristic features and general features.

We learned one of the reasons for the diversity of organic compounds

What else would you like to know about these compounds?

Homework.

Write in your notebook, pay attention to the features of homological series.

Rules, in the textbook. Paragraph "Limits"hydrocarbons" to chemical natural properties .

Literature.

O.S. Gabrielyan. Chemistry. 9th grade. M.: Bustard, 2007.

Sgibneva E.P., Skachkov A.V. Modern openchemistry lessons for grades 8-9. Rostov n/a "Phoenix" 2002

Classification of organic substances.

Chemistry can be divided into 3 large parts: general, inorganic and organic.

general chemistry examines patterns relating to all chemical transformations.

Inorganic chemistry studies the properties and transformations of inorganic substances.

Organic chemistry – This is a large and independent branch of chemistry, the subject of study of which is organic substances:

- their structure;

- properties;

- methods of obtaining;

- possibilities of practical use.

Name of organic chemistry suggested Swedish scientist Berzelius.

Before early 19th century All known substances were divided according to their origin into 2 groups:

1) mineral (inorganic) substances and

2) organic substances .

Berzelius and many scientists of those times believed that organic substances could only be formed in living organisms with the help of some kind of “vital force”. Such idealistic views were called vitalistic (from Latin “vita” - life). They delayed the development of organic chemistry as a science.

A German chemist dealt a big blow to the views of vitalists V. Wehler . He was the first to obtain organic substances from inorganic ones:

IN 1824 g. - oxalic acid, and

IN 1828 g. – urea.

In nature, oxalic acid is found in plants, and urea is formed in the body of humans and animals.

There were more and more similar facts.

IN 1845 German scientist Kolbe synthesized acetic acid from charcoal.

IN 1854 Mr. French scientist M. Berthelot synthesized a fat-like substance.

It became clear that there was no “life force”, that substances isolated from animal and plant organisms could be synthesized artificially, that they were of the same nature as all other substances.

Nowadays organic substances consider carbon-containing substances that are formed in nature (living organisms) and can be obtained synthetically. That's why organic chemistry is called chemistry of carbon compounds.

Features of organic substances .

Unlike inorganic substances, organic substances have a number of features that are determined by the structural features of the carbon atom.

Features of the structure of the carbon atom.

1) In molecules of organic substances, the carbon atom is in an excited state and exhibits a valence of IV.

2) During the formation of molecules of organic substances, the electronic orbitals of the carbon atom can undergo hybridization ( hybridization – this is the alignment of electron clouds in shape and energy).

3) Carbon atoms in molecules of organic substances are able to interact with each other, forming chains and rings.

Classification of organic compounds.

There are different classifications of organic substances:

1) by origin,

2) by elemental composition,

3) according to the type of carbon skeleton,

4) by type of chemical bonds,

5) according to the qualitative composition of functional groups.

Classification of organic substances by origin.

Classification of organic substances by elemental composition.

Organic matter
hydrocarbons	oxygen-containing	In addition to carbon, hydrogen and oxygen, they contain nitrogen and other atoms.
Consist of carbon and hydrogen	Consist of carbon, hydrogen and oxygen
Limiting HC
Unsaturated hydrocarbons		Amino acids
Aromatic hydrocarbons	Aldehydes
	Carboxylic acids	Nitro compounds
	Esters (simple and complex)
	Carbohydrates

Classification of organic substances according to the type of carbon skeleton.

Carbon skeleton –it is a sequence of carbon atoms chemically bonded to each other.

Classification of organic substances according to the type of chemical bonds.

Classification of organic substances according to the qualitative composition of functional groups.

Functional group – a permanent group of atoms that determines the characteristic properties of a substance.

Functional group	Name	Organic class	Suffixes and prefixes
-F, -Cl, -Br, -J	Fluorine, chlorine, bromine, iodine (halogen)	halogen derivatives	fluromethane chloromethane bromomethane iodomethane
	hydroxyl	Alcohols, phenols
- C = O	carbonyl	Aldehydes, ketones	- al methanal
- COUN	carboxyl	Carboxylic acids	methanoic acid
- NO2	nitro group	Nitro compounds	Nitro nitromethane
- NH2	amino group		- amine methylamine

Lesson 3-4

Topic: Basic principles of the theory of the structure of organic compounds

.

Reasons for the diversity of organic substances (homology, isomerism ).

By the beginning of the second half 19th century Quite a lot of organic compounds were known, but there was no single theory explaining their properties. Attempts to create such a theory have been made repeatedly. Not a single one was successful.

We owe the creation of the theory of the structure of organic substances .

In 1861, at the 36th Congress of German naturalists and doctors in Speyer, Butlerov made a report in which he outlined the main provisions of a new theory - the theory of the chemical structure of organic substances.

The theory of the chemical structure of organic substances did not arise out of nowhere.

The objective prerequisites for its appearance were :

1) socio-economic prerequisites .

The rapid development of industry and trade from the beginning of the 19th century placed high demands on many branches of science, including organic chemistry.

They set before this science new tasks:

- producing dyes synthetically,

- improvement of methods for processing agricultural products and etc.

2) Scientific background .

There were many facts that required explanation:

- Scientists could not explain the valence of carbon in compounds such as ethane, propane, etc.

- Scientists chemists could not explain why two elements: carbon and hydrogen can form such a large number of different compounds and why org. there are so many substances.

- It was not clear why organic substances with the same molecular formula (C6H12O6 - glucose and fructose) could exist.

The theory of the chemical structure of organic substances provided a scientifically substantiated answer to these questions.

By the time the theory appeared, much was already known :

- A. Kekule offered tetravalency of carbon atom for organic compounds.

- A. Cooper and A. Kekule suggested about carbon-carbon connections and the possibility of connecting carbon atoms in a chain.

IN 1860 . at the International Congress of Chemists were the concepts of atom, molecule, atomic weight, molecular weight are clearly defined .

The essence of the theory of the chemical structure of organic substances can be expressed as follows :

1. All atoms in molecules of organic substances are connected to each other in a certain order by chemical bonds according to their valency.

2. The properties of substances depend not only on which atoms and how many of them are included in the molecule, but also on the order in which the atoms are connected in the molecule .

Butlerov called the order of connection of atoms in a molecule and the nature of their bonds chemical structure .

The chemical structure of a molecule is expressed structural formula , in which the symbols of the elements of the corresponding atoms are connected by dashes ( valence primes) which indicate covalent bonds.

The structural formula conveys :

Sequence of connection of atoms;

Multiplicity of bonds between them (simple, double, triple).

Isomerism - This is the existence of substances that have the same molecular formula, but different properties.

Isomers - these are substances that have the same composition of molecules (the same molecular formula), but a different chemical structure and therefore have different properties.

3. By the properties of a given substance one can determine the structure of its molecule, and by the structure of the molecule one can predict properties.

The properties of substances depend on the type of crystal lattice.

4. Atoms and groups of atoms in the molecules of substances mutually influence each other.

The importance of theory.

The theory created by Butlerov was initially greeted negatively by the scientific world, since its ideas contradicted the prevailing idealistic worldview at that time, but after a few years the theory became generally accepted, the following circumstances contributed to this:

1. The theory brought order to the unimaginable chaos in which organic chemistry existed before it. The theory made it possible to explain new facts and proved that with the help of chemical methods (synthesis, decomposition, and other reactions) it is possible to establish the order of connection of atoms in molecules.

2. The theory introduced something new into atomic-molecular science

The order of atoms in molecules,

Mutual influence of atoms

Dependence of properties on the molecule of a substance.

3. The theory was able not only to explain already known facts, but also made it possible to foresee the properties of organic substances based on their structure and synthesize new substances.

4. The theory made it possible to explain manifold chemical substances.

5. It gave a powerful impetus to the synthesis of organic substances.

The development of the theory proceeded, as Butlerov foresaw, mainly in two directions :

1. Study of the spatial structure of molecules (the real arrangement of atoms in three-dimensional space)

2. Development of electronic concepts (identification of the essence of chemical bonds).

Lesson topic: “Classification and nomenclature of organic compounds”. Purpose of the lesson: Development of methodological knowledge, as well as knowledge about the diversity and differences in the properties of organic compounds. Introduce the concept of classes and functional groups. To acquaint schoolchildren with the classification and rules of: compiling structural formulas based on the name of an organic compound, compiling the names of organic compounds using a structural formula.

Lesson plan: 1 Organization of the beginning of the lesson. 2. Generalization of knowledge about the structural features of organic compounds 3. Variety of organic substances. 4. Classification of organic compounds. 5. Nomenclature of organic substances and its types. 6. Drawing up structural formulas based on the name of an organic compound. 7. Compiling the names of organic compounds according to the structural formula. 8. Summing up the lesson. 9. Discussion of homework.

Characteristics of carbon - carbon bonds Type Bond Types of hybridization of coval bond Sp Bond length, nm. Angle Shape Examples of Molecule Bonds

Characteristics of carbon - carbon bonds Type Bond Types Length Hybridization angle of covalene bond, nm. bond 0. 120 180 Sp = 0. 134 Molecule shape Linear 120 Planar trigonal 0. 154 109 Examples HC CH acetylene H 2 C=CH 2 ethylene H 3 C-CH 3 ethane Tetrahedral

VARNISHES PERFUME SUBSTANCES FIBERS Medicines Films Plant protective agents GLUE DYES Rubber Plastics Combustible Organic substances and materials Sources of organic compounds Coal Oil Gas Wood

CLASSES OF ORGANIC COMPOUNDS CLASS Carboxylic acids Aldehydes FUNCTIONAL GROUP -COOH -CHO Ketones C=O Alcohols, phenols -OH Amines -NH 2 Ethers** -OR Halogen derivatives -F -Cl -Br -I Nitro compounds -NO 2

Types of nomenclature for organic compounds Trivial (based on method of preparation) IUPAC nomenclature (substitute) Rational-functional (based on the simplest compounds)

One, two, three, four, five, Let's start counting the atoms. Learning new words: Meta - one, and this - two. Three - propane, butane - four, All neighbors in the apartment. The atomic ribbon winds, Number five will be penta. Six are hexane, and seven are heptane. Carbons, in places! And in octane, as in an octave, there are eight atoms in the composition. According to the Law, Atom nine means nona. Finally, like an idol, the dean rises.

Classification of organic compounds

Lesson objectives. Introduce the principles of classification of organic compounds according to the structure of the carbon chain and functional groups and, on this basis, provide an initial overview of the main classes of organic compounds.

Equipment: models of Stewart-Brigleb molecules, classification scheme for organic compounds.

I. General principles of classification of organic compounds

The teacher begins the explanation of new material with a reminder of how large the number of known organic compounds is. It is easy not only for a schoolchild, but also for an experienced chemist to drown in this vast ocean. Therefore, scientists always strive to classify any set “by sticks” and put things in order in their household. By the way, it doesn’t hurt for each of us to do this with our things, so that we know where everything is at any time.

Substances can be classified according to various criteria, for example, by composition, structure, properties, application - according to such a familiar logical system of characteristics. Since the composition of all organic compounds includes carbon atoms, then, obviously, the most important feature of the classification of organic substances can be the order of their connection, i.e., structure. On this basis, all organic substances are divided into groups depending on what kind of skeleton (skeleton) carbon atoms form, and whether this skeleton includes any other atoms except carbon.

Since the knowledge of tenth-graders in organic chemistry is still very poor, when explaining the material, it is advisable to have a diagram made in the form of a poster or shown in advance on the board (Fig. 1). The teacher, moving from top to bottom along the diagram, explains terms that are new to students, making extensive use of the etymology (origin) of chemical terms. Thus, during the explanation, the principle of humanitarization of learning is implemented.

Fig 1. Classification of organic compounds

Such an explanation can be presented, for example, since it is known that carbon atoms, when combined with each other, can form chains of various lengths. If such a chain is not closed, the substance belongs to the group of acyclic (non-cyclic) compounds. The closed chain of carbon atoms allows the substance to be called cyclic.

Carbon atoms in a chain can be connected by simple (single) or double or triple (multiple) bonds. If a molecule has at least one multiple carbon-carbon bond, it is called unsaturated or unsaturated, otherwise - saturated (saturated).

If the closed chain of a cyclic substance consists only of carbon atoms, it is called carbocyclic. However, instead of one or more carbon atoms, the cycle may contain atoms of other elements, for example nitrogen, oxygen, sulfur. They are sometimes called heteroatoms, and the compound is called heterocyclic.

In the group of carbocyclic substances there is a special “shelf” on which substances with a special arrangement of double and single bonds in the ring are located. Students have already encountered one of these substances - benzene - in the 9th grade course. Benzene, its closest and distant “relatives” are called aromatic substances, and the remaining carbocyclic compounds are called alicyclic.

The most important goal of this lesson is to introduce students to the basic terms used in the classification of organic substances, but it is premature to require a complete understanding of each term at this stage. Children simply must be able to classify substances based on their chemical structure into one group or another. In addition, in the future, when studying individual classes of substances, it is advisable to return to this scheme and focus on which group of compounds the substances of the class being studied belong to. In this case, the difficult terms of this lesson will be filled with specific content and will be better remembered.

II. Main classes of organic compounds

The teacher can build this part of the lesson in terms of repeating the material from the 9th grade course. Students are given homework the day before to remember which organic classes they studied last year. The guys take turns going to the board, writing the name of the class (in the order they were studied), the formula and the name of one of the representatives of the class, for example:

Saturated hydrocarbons (alkanes): CH 3 -SN 3 , ethane.

Unsaturated (ethylene) hydrocarbons (alkenes): CH 2 =CH 2 , ethylene.

The teacher interrupts this process with a number of additions. For example, after considering alkenes, he reports that a hydrocarbon molecule can have not one, but two or more double bonds. Very important from a practical point of view are substances containing two double bonds - diene hydrocarbons or alkadienes. The teacher writes the class name, formula and name of butadiene-1,3 on the board. If no question arises, you don’t have to focus on the nomenclature rules for constructing this name - everything has its time. Similarly, after benzene, as a representative of aromatic hydrocarbons, the teacher gives an example of one of the alicycles, for example cyclohexane. Attention should be paid to the following points: a) despite the similarity of structure, benzene and cyclohexane belong to different types of substances (according to the classification scheme); b) it follows from this how important it is to show the presence of multiple bonds in cyclic molecules.

After the names of all classes of hydrocarbons have appeared on the board, it is necessary to formulate the concept of a functional group. Many students remember the hydroxyl, aldehyde, carboxyl groups, and amino groups. Formulas for representatives of the class of alcohols, aldehydes, and carboxylic acids appear on the board. The teacher supplements this list with simple and esters, ketones, amines and nitro compounds.

Students try to answer the question of what they understand by the terms bi- or polyfunctional compounds. As an example of a bifunctional compound, the teacher gives the formula of the amino acid glycine. At the end of the review, he once again explains what heterocyclic substances are and writes down the formulas of pyridine (using an analogy with benzene) and morpholine (an analogy with cyclohexane).

Familiarization with the main classes of organic compounds does not imply memorization of this material by all students; only strong children can do this. However, general familiarity with this material is necessary to understand the logic of the further presentation of the course. The teacher recommends making a cheat sheet on thick paper with table 3 from the textbook. In the future, it will be useful for recognizing classes of substances when compiling their names. You can teach children to use this table when completing the following tasks.

Task 1. Using the classification scheme for organic compounds, use the formulas to determine the classes to which the following substances belong.

1st level

2nd level

Task 2. Using a cheat sheet, distribute the indicated formulas of substances into classes and name the classes of compounds to which they belong.

1st level

2nd level

Objectives: to introduce students to trivial names and rational nomenclature; give a general idea of ​​the basic principles of forming the names of organic compounds according to the international nomenclature; to develop the ability to name organic compounds according to the international nomenclature, to compose structural formulas by name.

Equipment: cards - tips “Main classes of organic compounds”, algorithm for composing formulas and names, classification of functional groups by seniority, cards with formulas of organic substances, cards for individual questioning, presentation for the lesson, projector, computer, interactive board.

During the classes.

Organizational moment: class readiness for the lesson, goals and objectives of the lesson. Updating of knowledge Independent work of students using cards on the classification of organic substances (2 people) – 3 minutes.
Frontal conversation with students on the following questions:

a) What substances are classified as organic?

b) What is called a homological series?

c) What substances are called homologues?

d) What substances are called isomers?

e) What is the valency of the carbon atom in all organic compounds?

f) What is a functional group?

g) What bonds are classified as multiple bonds and what classes of substances are they characteristic of?

h) What classes of organic compounds do you know? slide 1

Give examples.

i) Now we have named mainly hydrocarbons. But there are also oxygen-containing ones. For example…

i) What classes do these substances belong to (on cards):

CH3 – CH = CH2 ; C2H5COOH; C H3 – NH2; С2H5 – О – С2Н5; CH ≡ CH;

3. Checking the completion of S.R. slide 2

III. Learning new material.

Teacher: So, we are starting to consider new material. I ask you to open your notebooks, write down the date and topic of today’s lesson - “Nomenclature of organic compounds” slide 3

What does the word "nomenclature" mean? slide 4

Nomenclature is a system of names used in any science.

Chemical nomenclature is a system of formulas and names of chemical substances. It includes rules for composing formulas and names.

The names of organic compounds are complex words including:

1. designation of carbon chains;

2. designation of side chains;

3. designation of the multiplicity of bonds between atoms;

4. designation of characteristic groups;

5. numerical prefixes (multiplying prefixes);

6. numbers or letters (locants);

7. separators (hyphens, commas, periods, parentheses).

We will get acquainted with the basics of forming the names of organic compounds according to international nomenclature.

A little historical background.

In addition to the international nomenclature, organic chemistry uses: slide 5

Student 1: Trivial (historical) nomenclature is the first nomenclature that arose at the beginning of the development of organic chemistry, when there was no classification and theory of the structure of organic compounds. Organic compounds were given random names based on their source (oxalic acid, malic acid, vanillin), color or smell (aromatic compounds), and less often - by

chemical properties (paraffins). Many such names are still often used today. For example: urea, toluene, xylene, indigo, acetic acid, butyric acid, valeric acid, glycol, alanine and many others.

Teacher: Yes, of course, chemists even now rarely call acetylene ethine, and formic acid - methane acid. The next type of nomenclature is rational.

Student 2: Rational nomenclature - according to this nomenclature, the name of the simplest (usually the first) member of a given homologous series is usually taken as the basis for the name of an organic compound. All other compounds are considered as derivatives of this compound, formed by replacing hydrogen atoms in it with hydrocarbon or other radicals (for example: trimethylacetic aldehyde, methylamine, chloroacetic acid, methyl alcohol). Currently, such nomenclature is used only in cases where it gives a particularly clear idea of ​​the connection.

Teacher: Thank you.

The number of organic compounds is growing exponentially. It became difficult for chemists from different countries to communicate, since the same substances had different names, and several substances were meant under the same name. Chemists from all countries that are members of the International Union of Pure and Applied Chemistry (IUPAC) created a special committee that developed the basis for a unified nomenclature for all organic substances. This nomenclature is called international or systematic IUPAC nomenclature.

Systematic nomenclature is based on the modern theory of the structure and classification of organic compounds and attempts to solve the main problem of nomenclature: the name of each organic compound must contain the correct names of the functions (substituents) and the main skeleton of the hydrocarbon and must be such that the name can be used to write the only correct structural formula.

Basics of the international nomenclature of organic compounds.

In order to be able to use it, you need very little:

Know the information in Table 3. “Main classes of organic compounds” on page 33 of the textbook and supplemented in the notebook and be able to use them. slide 6 It is good to know the names of the first representatives of the homologous series of saturated hydrocarbons (from methane to decane) and radicals. Table in notebook on the first page. And for repetition, I offer the following poem, and you help me: slide 7

One, two, three, four, five, Six is ​​hexane, and seven is heptane.

Learning new words: And in octane, as in octave,

Meta - one, and this one - two. Eight atoms in composition.

Three - propane, butane - four, According to the Law

All flatmates. Atom nine means nona.

The atomic ribbon curls, Finally, like an idol,

Number five would be penta. The dean rises.

If a given number of carbon atoms is in the main chain, then we use the names according to the number of carbon atoms, but if the chain is a side chain, i.e., a hydrocarbon radical, then we take the names of the radical (with the suffix - silt). slide 7

Carbon chain names

Chain Main Side (hydrocarbon radical)

C meth methyl

C2 et ethyl

C3 prop cut

C4 butyl butyl

C5 pent pentyl

C6 hex hexyl

C7 hept heptyl

C9 non nonyl

It is necessary to remember the multiplicity of connections and the suffixes that are used.

Designation of the degree of saturation of bonds

С-С С=С С≡С

And, lastly, you need to know the names of numerical prefixes indicating the number of identical structural elements.

It’s good to know the algorithm for naming substances with an acyclic structure: the algorithm is right before your eyes, at home paste this piece of paper into your notebook, and the textbook page 37 also helps us.

1. Select the longest carbon chain. immediately with an example

2. Number it on the side to which the radicals, or the senior substituent, or the multiple bond are closest (depending on the class of the substance).

The order of precedence of the main groups is shown in the table. This table is on your desk.

Slide 8 Fig. 2

as well as the order of seniority of the main groups is also indicated on page 37 of the textbook.

3. Indicate in the prefix (the same prefixes, but specific, chemical)

position (carbon atom number) and name of the radical, substituent, functional group in alphabetical order.

4. Write down the root corresponding to the number of carbon atoms in the main chain.

5. If there is a double bond, then after the root put the suffix - en indicating the position of the bond in the chain; For a triple connection, use the suffix - in. If there are no multiple connections, the suffix is ​​an.

6. After this, indicate the suffix corresponding to the ketone, aldehyde or acid if there are corresponding functional groups. For ketones, the position of the functional group is indicated.

7. If a substance contains several identical radicals, substituents, bonds or functional groups, then they are named together, using numerals:

2 – di, 3 – three, 4 – tetra, etc.

8. When writing the name, all numbers are separated from each other by commas, and from letters - by hyphens.

1. Example: (understood by the teacher on the board, point by point of the algorithm)

CH3 – CH – CH – CH – COOH

CH3 CH3 NH2 2 - amino – 3,4 – dimethylpentanoic acid.

1. Since there are five carbon atoms in the main chain, the basis of the name is pentane.

2. The molecule has a functional group - - carboxyl COOH. Its presence is indicated by oic acid

3. There are three substituents in the main chain:

amino group, its position is indicated by the number 2,

and two methyl groups. The number of methyl groups is indicated by the particle di-, and the position in the chain by the numbers 3,4. There is a comma between numbers, numbers are separated from letters by a hyphen.

Analysis of several examples on the table of nomenclature of organic substances.

(Table 5 and Table 6).

III Consolidation.

Give your own names to the organic substances indicated on the board, slide 9:

CH ≡ C - CH2 - CH - CH2 - CH3 CH3 - CH2 - C = CH - COOH

CH2 - CH - CH2 - CH2 - CH3 CH3 - C = CH - CH3

CH2 = C - CH - CH2 - CH2 - CH3

C2H5 CH3 checking the completion of the task at the board.

1. Decipher the name of the substance whose formula is: slide 10

CH3 – C = CH – CH2 – CH3

CH3 2 – methylpentene – 2

1. There are 5 carbon atoms in the main chain, so the basis of the name is pentane (after the name of the corresponding alkane).

2. Since the molecule has a double bond, the suffix - an at the base of the name changes to - en.

3. After the base of the name, the position of the double bond in the chain is indicated: it starts from the second carbon atom.

4. The main chain has one substituent - methyl CH3. It is called before the base of the name indicating the position in the chain: at the second carbon atom.

Work in pairs. slide 11

1. Name the substance according to the international nomenclature:

HO – CH2 - C – CH2 - CH3

2. Make up the formula of the substance: 2,3 – dimethylbutene – 1.

(using algorithm 2)

3. Check that the task was completed correctly.

IV. Practicing the skills of drawing up a formula for an organic substance based on its name.

To complete this part of the lesson, use the virtual school disk “Chemistry Lessons of Cyril and Methodius, grades 10–11” - drawing up formulas.

V. slide 12. Homework: § 6, learn the names of alkanes, the first three radicals, the names of four numerical prefixes, the algorithm for naming substances with an acyclic structure,

Ex. 1 (b, d, e, f), 2 (a, b, c, d). p.38

school-collection. edu. ru A unified collection of digital educational resources, in the “collections” section. Nomenclature of organic substances.

V. Lesson summary. Ratings.

Used Books:

1. Chemistry 10th grade.

2. . Handbook for chemistry teacher, grade 10

3. . Chemistry in diagrams and tables

4. . Organic chemistry. Tasks and exercises.