Органическая химия = Organic Chemistry. Лабораторный практикум

ORGANIC CHEMISTRY

LABORATORY WORKSHOP

For students studying «Agricultural Science» and «Veterinary Science»

Moscow

Peoples’ Friendship University of Russia

2018

Authors:

L.N. Kulikova, A.V. Listratova, R.S. Borisov, E.A. Sorokina

Авторы:

Л.Н. Куликова, А.В. Листратова, Р.С. Борисов, Е.А. Сорокина

О-64 Органическая химия = Organic Chemistry =: лабораторный практикум / Л. Н. Куликова, А. В. Листратова, Р. С. Борисов, Е. А. Сорокина. – Москва : РУДН, 2018. – 36 с. : ил.

For students studying «Agricultural Science» and «Veterinary Science»

General rules for the fulfillment of laboratory works:

To be allowed to take part in laboratory works the student must be prepared for them. At home in the workbook the student should fill in the first two columns (the procedure of the experiments and all the reaction equations) of the table for the laboratory work(s) which he/she is going to perform at class. After the experimental part the student should write the observations about the obtained results. All the notes must be written with a pen using dark blue or black inks. Works written in pencil are not checked and estimated by the lecturer.

The preparation for the laboratory works is the obligatory requirement for the student to be allowed for them. The student, which is not prepared for the laboratory work, loses half of the points for the laboratory work and has to work it off next time, when it is convenient for the laboratory assistant.

Without all laboratory works done and checked, the student is not allowed to the final assessment! Please, do not forget to bring labcoats.

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HYRDROCARBONS

The hydrocarbons are compounds containing carbon and hydrogen only. There are three types of them: saturated (alkanes), unsaturated (alkenes and alkynes) and aromatic compounds. According to the connection of carbon atoms the hydrocarbons can be classified on their structure as open-chain compounds (unbranched and branched) and cyclic. In hydrocarbons carbon atom can be sp3- (alkanes), sp2- (alkenes) or sp-hybridized (alkynes and aromatic compounds).

Comparative characteristic of hydrocarbons

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Reactivity

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All the hydrocarbons (alkanes, alkenes and alkynes) complete combustion to carbon dioxide and water.

Laboratory work №1. Hydrocarbons (alkanes, alkene, alkynes)

№ Procedure Equations of reactions Observations Exp

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2Interactions of alkanes and alkenes with

Accurately shake both test tubes.

Add phenylacetylene into the test tubes. You must work with phenylacetylene in the fume hood.

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Aromatic Compounds

Cyclic unsaturated compounds with conjugated system of double bonds are called aromatic compounds.

The simplest member of this class is benzene, C6H6. The complex of specific properties of benzene – high stability, inactivity in addition reactions and susceptibility to substitution reactions – was defined as “aromaticity” or “aromatic properties”.

Aromaticity criteria:

a.Planar (flat) structure of the molecule;

b.Closed (cyclic) conjugated system;

c.Number of π-electrons (electrons in the conjugated system) should satisfy Hückel’s rule: 4n+2 where n = 0, 1, 2, 3 etc.

4n+2=6 4n+2=8

The most common type of reactions for aromatic compounds is electrophilic substitution.

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The nature of substituents in benzene ring causes the redistribution of π-electron density. Thus, during electrophilic aromatic substitution in such aromatic systems a new substituent “will be led” to the certain positions towards the already-present. Substituents are grouped into two categories: ortho-, para-directing and meta-directing. The ring with activating (ortho-, para- directing) substituents will react faster than benzene itself, whereas with deactivating (meta-directing) substituents will react more slowly.

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Addition reactions are not common for aromatic compounds and proceed under rigid conditions.

Despite the presence of three double bonds benzene does not decolorize bromine water and KMnO4 aqueous solution at 20 °С making these reactions special.

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