Wróć do informacji o e-podręczniku Wydrukuj Pobierz materiał do PDF Pobierz materiał do EPUB Pobierz materiał do MOBI Zaloguj się, aby dodać do ulubionych Zaloguj się, aby skopiować i edytować materiał Zaloguj się, aby udostępnić materiał Zaloguj się, aby dodać całą stronę do teczki
RQAEbX4QMEm92

Alcohols – structure

Link to the lesson

Before you start you should know
  • what is the valence of carbon in organic compounds;

  • how saturated hydrocarbons are built;

  • how to draw a structural formula of a given hydrocarbon;

  • how to create hydrocarbon’ names.

You will learn
  • what alcohols are;

  • to write down molecular and structural formulas of simple alcohols;

  • to recognize formulas of alcohols based on the functional group.

R1Thzfs9gvaPh
Nagranie dźwiękowe abstraktu

Hydrocarbon derivatives

Alcohols are derivatives of hydrocarbon where carbon atom (or atoms) was (were) replaced with hydroxyl functional group –OH, so‑called hydroxyl group (hydrogenium is the Latin name of hydrogen, oksygenium – of oxygen).
If one hydrogen atom in an alkane molecule is replaced with one hydroxyl group, then a compound consisting of a hydrocarbon chain (R) and alcohol functional group –OH is formed.

Task 1

Watch presentation. Memorize how alcohol formulas are created.

Formula of monohydric alcohol is:

R – OH

Alcohol names can consist of one or two parts.

Alcohols containing one hydroxyl group in the molecule, like hydrocarbons, form a homologous series. The name of an alcohol derived from an alkane is formed from the name of an alkane with the same number of carbon atoms in the molecule, adding to it the ending -ol and removing the ending -e, e.g. methanol is a methane derivative, ethanol – an ethane derivative. Names of alcohols consisting of two parts are formed by adding the name derived from particular hydrocarbon to the ‘alcohol’, changing the ending -ane into -yl, e.g. methyl alcohol.

CnH2n+2

General formula of monohydric alcohol is formed by replacing one hydrogen atom by hydroxyl functional group –OH in alkanes.

CnH2n+1OH

The table contains alcohols ranked according to the increasing number of carbon atoms. Each of the following compounds differs from the previous one by group CH2. This series is called the homologous seriesalcohol homologous serieshomologous series.

Name of alcohol

Formulas

methanol
(methyl alcohol)

CH3OH

CH3 – OH

etahnol
(ethyl alcohol)

C2H5OH

CH3CH2 – OH

propan–1–ol
(propyl alcohol)

C3H7OH

CH3CH2CH2 – OH

butan–1–ol
(butyl alcohol)

C4H9OH

CH3 CH2CH2 CH2 – OH

Exercise 1

The hydroxyl group may be attached to different carbon atoms. Determine butanol formulas on the basis of a general formula of monohydric alcohols derived from alkanes.

In monohydric alcohol molecules the hydroxyl group can be attached to various atoms of carbon. This phenomenon is called position isomerism. The number contained in the alcohol name indicates the number of the carbon atom where the –OH group is located.

RGQN6fOqJMfkG

Methyl alcohol

Alcohol with the simplest structure derives from methane, which means that its molecule contains only one carbon atom. One hydrogen atom in methane is replaced by functional groupfunctional groupfunctional group. Due to the number of OH groups, it is a monohydric alcohol. Methanol is a methane derivative.

RqYrovKNfzP0e
R1QW1FQ7OBGDO

Ethyl alcohol

The process of alcohol fermentation occurs under the influence of a special yeast species found in the peels of ripe grapes (or other fruits). Glucose – sugar contained in fruit juice – under favourable conditions, undergoes a chemical reaction where ethyl alcoholalcoholsalcohol is produced.

Reaction equation – in words:

glucose yeast ethyl alcohol + carbon dioxide

Reaction equation – molecular form:

C6H12O6yeasts 2CH3CH2OH + 2CO2

The reaction equation shows that alcohol fermentationalcohol fermentationalcohol fermentation is a process that takes place under the influence of yeast. Its products are ethyl alcohol and carbon dioxide.

R1CdO4wl07u0q

Ethyl alcohol contains as many carbon and hydrogen atoms as ethane. Due to this similarity of composition, ethanol is one of ethane derivatives.

RRrO0eFf7DUm6

Based on the position of carbon in the periodic table, we can conclude that the atom of this element has four valence electrons. Thus, it can create up to four bonds in organic compounds. In the ethyl alcohol molecule, the carbon atoms are connected with each other by a single bond. The oxygen atom forms two bonds: one with a hydrogen atom and one with a carbon atom. Each of the hydrogen atoms is monovalent, i.e. it creates only one bond.

Molecular formula of alcohol does not inform how the molecule is build. Thus, to determine differences in structure of various of alcohols, structural forms are used.

Ethanol formula:

C2H5OH

R13yBDuM1dCgD
Ri1r53FdyWARB
Exercise 2
Assign appropriate names to formulas of alcohol methanol, butyl alcohol, propanol, ethyl alcohol, pentanol. Możliwe odpowiedzi: ce ha trzy o ha, ce cztery ha dziesięć o, ce trzy ha osiem o, ce dwa ha sześć o, ce pięć ha dwanaście o.
RJZh43heZegNC
Exercise 3
Arrange the homologous series of alcohols. Elementy do uszeregowania: 1. propanol, 2. hexanol, 3. heptanol, 4. ethanol, 5. pentanol, 6. butanol
RAmG27Bs0j8o2
Exercise 4
Choose correct name of the compound of following formula ce dwa ha pięć o ha. Możliwe odpowiedzi: 1. ethyl alcohol, 2. methanol, 3. methyl alcohol, 4. ethane, 5. butyl alcohol, 6. propylic alcohol

Summary

  • The alcohol fermentation products are ethanol and carbon dioxide.

  • Monohydric alcohols are compounds in which one hydrogen atom has been replaced by a monovalent group OH.

  • Methanol and ethanol contain one functional group in their molecules. These are monohydric alcohols.

  • Alcohols have many applications.

R18Tcfx8PL0qw1
Grafika przedstawiająca tablicę szkolną, na której znajdują się zdania do dokończenia. Finish selected sentences. 1 It was easy for me (uzupełnij). 2 It was difficult for me (uzupełnij). 3 Today I learned (uzupełnij). 4 I understood that (uzupełnij). 5 It surprised me (uzupełnij). 6. Today I found out (uzupełnij). 7. I was interested in (uzupełnij). 8. I still have to repeat (uzupełnij).
Source: GroMar Sp. z o.o., licencja: CC BY-SA 3.0.
Homework
Task 2.1

Write down the general formula of monohydric alcohols. Select the hydrocarbon part and functional group.

Keywords

alcohol, hydrocarbons, monohydric alcohols, methanol, ethanol, homologous series, methyl alcohol, ethyl alcohol, position isomerism

Glossary

alcohols
alcohols
R1BIXGPA8ILby
Nagranie dźwiękowe słówka

alkohole – pochodne węglowodorów, w których co najmniej jeden atom wodoru zastąpiono grupą hydroksylową

alcohol fermentation
alcohol fermentation
RnNNAcd5GhYZK
Nagranie dźwiękowe słówka

fermentacja alkoholowa – przemiana glukozy pod wpływem enzymów wytwarzanych przez drożdże; jej produktami są alkohol etylowy i tlenek węgla(IV)

functional group
functional group
RiDv3JF01rOEa
Nagranie dźwiękowe słówka

grupa funkcyjna – grupa atomów (lub atom) połączona z łańcuchem węglowym w węglowodorach; jej obecność decyduje o przynależności do danej grupy związków organicznych

alcohol homologous series
alcohol homologous series
R1bM9kRsBoVqJ
Nagranie dźwiękowe słówka

szereg homologiczny alkoholi – szereg alkoholi uporządkowanych według wzrastającej liczby atomów węgla w cząsteczce; dwa kolejne związki różnią się od siebie o grupę atomówCH2