Alkanes methods of obtaining physical properties nomenclature. Alkanes. General characteristics: structure, isomerism, nomenclature. Homologous series of saturated hydrocarbons

The simplest organic compounds are hydrocarbons, consisting of carbon and hydrogen. Depending on the nature of the chemical bonds in hydrocarbons and the ratio between carbon and hydrogen, they are divided into saturated and unsaturated (alkenes, alkynes, etc.)

Limit hydrocarbons (alkanes, methane hydrocarbons) are compounds of carbon with hydrogen, in the molecules of which each carbon atom spends no more than one valence on combining with any other neighboring atom, and all valencies not spent on combining with carbon are saturated with hydrogen. All carbon atoms in alkanes are in the sp 3 state. Saturated hydrocarbons form a homologous series characterized by the general formula C n H 2n+2. The ancestor of this series is methane.

Isomerism. Nomenclature.

Alkanes with n=1,2,3 can only exist as one isomer

Starting from n=4, the phenomenon of structural isomerism appears.

The number of structural isomers of alkanes grows rapidly with increasing number of carbon atoms, for example, pentane has 3 isomers, heptane has 9, etc.

The number of isomers of alkanes also increases due to possible stereoisomers. Starting from C 7 H 16, the existence of chiral molecules is possible, which form two enantiomers.

Nomenclature of alkanes.

The dominant nomenclature is the IUPAC nomenclature. At the same time, it contains elements of trivial names. Thus, the first four members of the homologous series of alkanes have trivial names.

CH 4 - methane

C 2 H 6 - ethane

C 3 H 8 - propane

C 4 H 10 - butane.

The names of the remaining homologues are derived from Greek Latin numerals. Thus, for the following members of a series of normal (unbranched) structure, the names are used:

C 5 H 12 - pentane, C 6 H 14 - hexane, C 7 H 18 - heptane,

C 14 H 30 - tetradecane, C 15 H 32 - pentadecane, etc.

Basic IUPAC Rules for Branched Alkanes

a) choose the longest unbranched chain, the name of which forms the base (root). The suffix “an” is added to this stem.

b) number this chain according to the principle of smallest locants,

c) the substituent is indicated in the form of prefixes in alphabetical order indicating the location. If there are several identical substituents in the original structure, then their number is indicated by Greek numerals.

Depending on the number of other carbon atoms to which the carbon atom in question is directly bonded, there are primary, secondary, tertiary and quaternary carbon atoms.

Alkyl groups or alkyl radicals appear as substituents in branched alkanes, which are considered as a result of the elimination of one hydrogen atom from the alkane molecule.

The name of alkyl groups is formed from the name of the corresponding alkanes by replacing the latter suffix “an” with the suffix “yl”.

CH 3 - methyl

CH 3 CH 2 - ethyl

CH 3 CH 2 CH 2 - cut

To name branched alkyl groups, chain numbering is also used:

Starting from ethane, alkanes are able to form conformers that correspond to a inhibited conformation. The possibility of transition from one inhibited conformation to another through an eclipsed one is determined by the rotation barrier. Determination of the structure, composition of conformers and rotation barriers are the tasks of conformational analysis.

2. Chemical properties of alkanes (methane, ethane): combustion, substitution, decomposition, dehydrogenation.

All bonds in alkanes are low-polar, which is why they are characterized by radical reactions. The absence of pi bonds makes addition reactions impossible.

Alkanes are characterized by substitution, elimination, and combustion reactions.

1. Substitution reactions

A) with halogens(With chlorine Cl 2 – in the light, Br 2 - when heated) the reaction obeys Markovnik's rule (Markovnikov's Rules) - first of all, a halogen replaces hydrogen at the least hydrogenated carbon atom. The reaction takes place in stages - no more than one hydrogen atom is replaced in one stage.

Iodine reacts most difficultly, and moreover, the reaction does not go to completion, since, for example, when methane reacts with iodine, hydrogen iodide is formed, which reacts with methyl iodide to form methane and iodine (reversible reaction):

CH 4 + Cl 2 → CH 3 Cl + HCl (chloromethane)

CH 3 Cl + Cl 2 → CH 2 Cl 2 + HCl (dichloromethane)

CH 2 Cl 2 + Cl 2 → CHCl 3 + HCl (trichloromethane)

CHCl 3 + Cl 2 → CCl 4 + HCl (carbon tetrachloride)

B) Nitration (Konovalov reaction)

Alkanes react with a 10% solution nitric acid or nitrogen oxide N 2 O 4 in the gas phase at a temperature of 140° and low pressure with the formation of nitro derivatives. The reaction also obeys Markovnikov's rule. One of the hydrogen atoms is replaced by the NO 2 residue (nitro group) and water is released

Elimination reactions

A) dehydrogenation– elimination of hydrogen. Reaction conditions: catalyst – platinum and temperature.

CH 3 - CH 3 → CH 2 = CH 2 + H 2

B) cracking the process of thermal decomposition of hydrocarbons, which is based on the reactions of splitting the carbon chain of large molecules to form compounds with a shorter chain. At a temperature of 450–700 o C, alkanes decompose due to the cleavage of C–C bonds (stronger C–H bonds are retained at this temperature) and alkanes and alkenes with a smaller number of carbon atoms are formed

C 6 H 14 C 2 H 6 + C 4 H 8

B) complete thermal decomposition

CH 4 C + 2H 2

Oxidation reactions

A) combustion reaction When ignited (t = 600 o C), alkanes react with oxygen, and they are oxidized to carbon dioxide and water.

C n H 2n+2 + O 2 ––>CO 2 + H 2 O + Q

CH 4 + 2O 2 ––>CO 2 + 2H 2 O + Q

B) Catalytic oxidation- at a relatively low temperature and with the use of catalysts, it is accompanied by the rupture of only part of the C–C bonds approximately in the middle of the molecule and C–H and is used to obtain valuable products: carboxylic acids, ketones, aldehydes, alcohols.

For example, with incomplete oxidation of butane (cleavage of the C 2 –C 3 bond) one obtains acetic acid

4. Isomerization reactions are not typical for all alkanes. Attention is drawn to the possibility of converting some isomers into others and the presence of catalysts.

C 4 H 10 C 4 H 10

5.. Alkanes with a main chain of 6 or more carbon atoms also react dehydrocyclization but always form a 6-membered ring (cyclohexane and its derivatives). Under reaction conditions, this cycle undergoes further dehydrogenation and turns into the more energetically stable benzene cycle aromatic hydrocarbon(arena).

Alkanes :

Alkanes are saturated hydrocarbons, in the molecules of which all atoms are connected by single bonds. Formula -

Physical properties :

• Melting and boiling points increase with molecular weight and the length of the main carbon chain
• Under normal conditions, unbranched alkanes from CH 4 to C 4 H 10 are gases; from C 5 H 12 to C 13 H 28 - liquids; after C 14 H 30 - solids.
• Melting and boiling points decrease from less branched to more branched. So, for example, at 20 °C n-pentane is a liquid, and neopentane is a gas.

Chemical properties:

· Halogenation

this is one of the substitution reactions. The least hydrogenated carbon atom is halogenated first (tertiary atom, then secondary, primary atoms are halogenated last). The halogenation of alkanes occurs in stages - no more than one hydrogen atom is replaced in one stage:

1. CH 4 + Cl 2 → CH 3 Cl + HCl (chloromethane)
2. CH 3 Cl + Cl 2 → CH 2 Cl 2 + HCl (dichloromethane)
3. CH 2 Cl 2 + Cl 2 → CHCl 3 + HCl (trichloromethane)
4. CHCl 3 + Cl 2 → CCl 4 + HCl (carbon tetrachloride).

Under the influence of light, a chlorine molecule breaks down into radicals, then they attack alkane molecules, taking away a hydrogen atom from them, as a result of which methyl radicals CH 3 are formed, which collide with chlorine molecules, destroying them and forming new radicals.

· Combustion

The main chemical property of saturated hydrocarbons, which determines their use as fuel, is the combustion reaction. Example:

CH 4 + 2O 2 → CO 2 + 2H 2 O + Q

In case of lack of oxygen, carbon monoxide or coal is produced instead of carbon dioxide (depending on the oxygen concentration).

IN general view The combustion reaction of alkanes can be written as follows:

WITH n H 2 n +2 +(1,5n+0.5)O 2 = n CO 2 + ( n+1)H 2 O

· Decomposition

Decomposition reactions occur only under the influence of high temperatures. An increase in temperature leads to the rupture of carbon bonds and the formation of free radicals.

Examples:

CH 4 → C + 2H 2 (t > 1000 °C)

C 2 H 6 → 2C + 3H 2

Alkenes :

Alkenes are unsaturated hydrocarbons containing in the molecule, in addition to single bonds, one carbon-carbon double bond. Formula - C n H 2n

The belonging of a hydrocarbon to the class of alkenes is reflected by the generic suffix –ene in its name.

Physical properties :

• The melting and boiling points of alkenes (simplified) increase with molecular weight and length of the carbon backbone.
• Under normal conditions, alkenes from C 2 H 4 to C 4 H 8 are gases; from C 5 H 10 to C 17 H 34 - liquids, after C 18 H 36 - solids. Alkenes are insoluble in water, but are highly soluble in organic solvents.

Chemical properties :

· Dehydration is the process of splitting off a water molecule from a molecule of an organic compound.

· Polymerization is a chemical process of combining many initial molecules of a low molecular weight substance into large polymer molecules.

Polymer is a high-molecular compound whose molecules consist of many identical structural units.

Alcadienes :

Alkadienes are unsaturated hydrocarbons containing in the molecule, in addition to single bonds, double carbon-carbon bonds. Formula -

Physical properties :

Butadiene is a gas (boiling point −4.5 °C), isoprene is a liquid boiling at 34 °C, dimethylbutadiene is a liquid boiling at 70 °C. Isoprene and other diene hydrocarbons are capable of polymerizing into rubber. Natural rubber in its purified state is a polymer with the general formula (C5H8)n and is obtained from the milky sap of some tropical plants.

Rubber is highly soluble in benzene, gasoline, and carbon disulfide. At low temperatures it becomes brittle and sticky when heated. To improve the mechanical and chemical properties of rubber, it is converted into rubber by vulcanization. To obtain rubber products, they are first molded from a mixture of rubber with sulfur, as well as fillers: soot, chalk, clay and some organic compounds that serve to accelerate vulcanization. Then the products are heated - hot vulcanization. During vulcanization, sulfur chemically bonds with the rubber. In addition, vulcanized rubber contains sulfur in a free state in the form of tiny particles.

Diene hydrocarbons polymerize easily. The polymerization reaction of diene hydrocarbons underlies the synthesis of rubber. They undergo addition reactions (hydrogenation, halogenation, hydrohalogenation):

H 2 C=CH-CH=CH 2 + H 2 -> H 3 C-CH=CH-CH 3

Alkynes :

Alkynes are unsaturated hydrocarbons whose molecules contain, in addition to single bonds, one triple carbon-carbon bond. Formula-C n H 2n-2

Physical properties :

Alkynes resemble the corresponding alkenes in their physical properties. Lower (up to C 4) are colorless and odorless gases that have higher boiling points than their analogues in alkenes.

Alkynes are poorly soluble in water, but better in organic solvents.

Chemical properties :

Halogenation reactions

Alkynes are capable of adding one or two halogen molecules to form the corresponding halogen derivatives:

Hydration

In the presence of mercury salts, alkynes add water to form acetaldehyde (for acetylene) or ketone (for other alkynes)

Alkanes are compounds of the homologous series of methane. These are saturated non-cyclic hydrocarbons. The chemical properties of alkanes depend on the structure of the molecule and the physical state of the substances.

Structure of alkanes

An alkane molecule consists of carbon and hydrogen atoms, which form methylene (-CH 2 -) and methyl (-CH 3) groups. Carbon can form four covalent nonpolar bonds with neighboring atoms. It is the presence of strong σ-bonds -C-C- and -C-H that determines the inertness of the homologous series of alkanes.

Rice. 1. The structure of an alkane molecule.

The compounds react when exposed to light or heat. Reactions proceed by a chain (free radical) mechanism. Thus, bonds can only be broken down by free radicals. As a result of hydrogen substitution, haloalkanes, salts, and cycloalkanes are formed.

Alkanes are classified as saturated or saturated carbons. This means that the molecules contain the maximum number of hydrogen atoms. Due to the absence of free bonds, addition reactions are not typical for alkanes.

Chemical properties

General properties of alkanes are given in the table.

To understand how the reaction proceeds and which radicals are replaced, it is recommended to write down the structural formulas.

Rice. 2. Structural formulas.

Application

Alkanes are widely used in industrial chemistry, cosmetology, and construction. The compounds are made from:

• fuel (gasoline, kerosene);
• asphalt;
• lubricating oils;
• petrolatum;
• paraffin;
• soap;
• varnishes;
• paints;
• enamels;
• alcohols;
• synthetic fabrics;
• rubber;
• addehydes;
• plastics;
• detergents;
• acids;
• propellants;
• cosmetical tools.

Rice. 3. Products obtained from alkanes.

What have we learned?

Learned about the chemical properties and uses of alkanes. Due to the strong covalent bonds between carbon atoms, as well as between carbon and hydrogen atoms, alkanes are inert. Substitution and decomposition reactions are possible in the presence of a catalyst at high temperatures. Alkanes are saturated hydrocarbons, so addition reactions are impossible. Alkanes are used to produce materials detergents, organic compounds.

Test on the topic

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Alkanes (paraffins or saturated hydrocarbons)– the simplest class of organic compounds in terms of elemental composition. They are composed of carbon and hydrogen. The ancestor of this class is methane CH 4. All other hydrocarbons classified as alkanes are members of the homologous methane series. General formula of alkanes C n H 2 n +2

Carbon has four valence electrons on its outer shell, so it can form four two-electron covalent bonds with hydrogen atoms:

When moving to higher homologs, the number of isomers increases sharply (see above).

A carbon atom bonded to one adjacent carbon atom is called primary, with two - secondary, with three – tertiary and with four - quaternary:

Several nomenclatures can be used to name alkanes: historical or trivial nomenclature - This is a summary of historically established names for commonly used organic compounds. – rational nomenclature. When compiling a name according to this nomenclature, the compound is considered as obtained from the simplest representative of the series as a result of the replacement of hydrogen atoms in it by alkyl radicals.

– IUPAC nomenclature

Homologous series, a sequence of organic compounds with the same functional groups and a similar structure, each member of which differs from the neighboring one by a constant structural unit(homologous difference), most often the methylene group -CH 2 -. Members of a homologous series are called homologues. In homologous series, many physical properties change naturally. For example, the boiling points in the middle of a series of straight-chain compounds (C 5 -C 14) differ between neighboring homologues by 20-30 ° C; the homologous difference -CH 2 - corresponds to an increase in the heat of combustion by 630-640 kJ/mol and molecular refraction by 4.6 for the sodium D-line. In the higher members of the homologous series, these differences are gradually smoothed out.

Physical and Chemical properties alkanes. Methods for obtaining and identifying alkanes. Individual representatives.

Physical properties of alkanes.

The first four members of the series - methane, ethane, propane and butane - are gases at room conditions. Alkanes C 5 – C 15 are liquid, and C 16 and beyond are solid.

Under normal conditions

Chemical properties of alkanes

Hydrocarbons of the methane series are chemically very inert at ordinary temperatures. They do not add hydrogen (hence the limiting ones), do not react without initiation with Cl 2 and Br 2, and are not oxidized in the cold by such strong oxidizing agents as potassium permanganate and chromic acid. At the same time, these bonds are relatively easily subject to homolytic cleavage with the formation of radicals. That's why radical substitution reactions are more common for alkanes.

– Halogenation

In the light, alkanes can successively replace hydrogen atoms with halogen atoms, for example:

At temperature » 500 °C Methane is nitrated under the influence of nitric acid and nitrogen dioxide:

– Sulfonation

Sulfuric acid (oleum) slowly sulfonates alkanes when heated with tertiary carbon atom:

– Sulfochlorination

Under the influence of ultraviolet lighting, alkanes undergo a substitution reaction with a mixture of SO 2 + Cl 2:

– Oxidation

In isoalkanes, the tertiary group CH is relatively easily oxidized. Of industrial interest is the catalytic oxidation of a mixture of higher saturated hydrocarbons C 8 - C 18:

– Dehydrogenation

At t = 300 °C...400 °C, alkanes passed over the catalyst lose two hydrogen atoms and turn into alkenes:

– Isomerization

Under the influence of acid catalysts (for example, AlCl 3, H 2 SO 4, etc.), alkanes are capable of restructuring the carbon skeleton:

Methods for producing alkanes

– Hydrogenation of unsaturated hydrocarbons

– From alkyl halides ( Wurtz reaction, 1870)

– From carboxylic acids

– Cracking and pyrolysis of petroleum alkanes:

5. Alkenes. general characteristics: structure, isomerism, nomenclature.

The homologous series of alkenes begins with ethylene. Alkenes(olefins, ethylene hydrocarbons) – hydrocarbons that contain one double bond in the molecule. The general formula is C n H 2n.

Isomerism. Nomenclature

As in the series of saturated hydrocarbons, the structural isomerism of alkenes begins with the fourth member of the series. However, the number of isomers is much larger. The isomerism of olefins is determined by the structure of the carbon chain, secondly, by the position of the double bond in the chain, and thirdly, by the spatial arrangement of atoms or groups at carbons with a double bond

Alkenes are called by different nomenclatures. In trivial nomenclature, the suffix –ene is added to the name of the corresponding saturated hydrocarbon radical: ethylene, propylene, butylene, isobutylene, amylene, etc. According to rational nomenclature, olefins are called derivatives of ethylene. When naming the compound using IUPAC nomenclature, the longest carbon chain containing a double bond is selected as the backbone of the compound. The name is based on the name of the alkane with the ending -an replaced by
-en. The number indicates the number of the carbon atom followed by the double bond. The carbon atoms of the main chain should be numbered from the end to which the double bond is closest.

It would be useful to start with a definition of the concept of alkanes. These are saturated or saturated. We can also say that these are carbons in which the connection of C atoms is carried out through simple bonds. The general formula is: CnH₂n+ 2.

It is known that the ratio of the number of H and C atoms in their molecules is maximum when compared with other classes. Due to the fact that all valences are occupied by either C or H, the chemical properties of alkanes are not clearly expressed, so their second name is the phrase saturated or saturated hydrocarbons.

There is also an older name that best reflects their relative chemical inertness - paraffins, which means “devoid of affinity.”

So, the topic of our conversation today is: “Alkanes: homological series, nomenclature, structure, isomerism.” Data regarding their physical properties will also be presented.

Alkanes: structure, nomenclature

In them, the C atoms are in a state called sp3 hybridization. In this regard, the alkane molecule can be demonstrated as a set of tetrahedral C structures that are connected not only to each other, but also to H.

Between the C and H atoms there are strong, very low-polar s-bonds. Atoms always rotate around simple bonds, which is why alkane molecules take on various shapes, and the bond length and the angle between them are constant values. Shapes that transform into each other due to the rotation of the molecule around σ bonds are usually called conformations.

In the process of abstraction of an H atom from the molecule in question, 1-valent species called hydrocarbon radicals are formed. They appear as a result of not only but also inorganic compounds. If you subtract 2 hydrogen atoms from a saturated hydrocarbon molecule, you get 2-valent radicals.

Thus, the nomenclature of alkanes can be:

• radial (old version);
• substitution (international, systematic). It was proposed by IUPAC.

Features of radial nomenclature

In the first case, the nomenclature of alkanes is characterized as follows:

1. Consideration of hydrocarbons as derivatives of methane, in which 1 or several H atoms are replaced by radicals.
2. High degree of convenience in the case of not very complex connections.

Features of substitution nomenclature

The substitutive nomenclature of alkanes has the following features:

1. The basis for the name is 1 carbon chain, while the remaining molecular fragments are considered as substituents.
2. If there are several identical radicals, the number is indicated before their name (strictly in words), and the radical numbers are separated by commas.

Chemistry: nomenclature of alkanes

For convenience, the information is presented in table form.

The above nomenclature of alkanes includes names that have developed historically (the first 4 members of the series of saturated hydrocarbons).

The names of unexpanded alkanes with 5 or more C atoms are derived from Greek numerals, which reflect given number atoms of C. Thus, the suffix -an indicates that the substance is from a series of saturated compounds.

When composing the names of unfolded alkanes, the main chain is the one that contains the maximum number of C atoms. It is numbered so that the substituents have the lowest number. In the case of two or more chains of the same length, the main one becomes the one that contains greatest number deputies

Isomerism of alkanes

The parent hydrocarbon of their series is methane CH₄. With each subsequent representative of the methane series, a difference from the previous one is observed in the methylene group - CH₂. This pattern can be traced throughout the entire series of alkanes.

The German scientist Schiel put forward a proposal to call this series homological. Translated from Greek it means “similar, similar.”

Thus, a homologous series is a set of related organic compounds that have the same structure and similar chemical properties. Homologues are members of a given series. Homologous difference is a methylene group in which 2 neighboring homologues differ.

As mentioned earlier, the composition of any saturated hydrocarbon can be expressed using the general formula CnH₂n + 2. Thus, the next member of the homologous series after methane is ethane - C₂H₆. To convert its structure from methane, it is necessary to replace 1 H atom with CH₃ (figure below).

The structure of each subsequent homolog can be deduced from the previous one in the same way. As a result, propane is formed from ethane - C₃H₈.

What are isomers?

These are substances that have identical qualitative and quantitative molecular composition (identical molecular formula), however different chemical structure, as well as having different chemical properties.

The hydrocarbons discussed above differ in such a parameter as boiling point: -0.5° - butane, -10° - isobutane. This type of isomerism is called carbon skeleton isomerism; it belongs to the structural type.

The number of structural isomers increases rapidly as the number of carbon atoms increases. Thus, C₁₀H₂₂ will correspond to 75 isomers (not including spatial ones), and for C₁₅H₃₂ 4347 isomers are already known, for C₂₀H₄₂ - 366,319.

So, it has already become clear what alkanes are, homologous series, isomerism, nomenclature. Now it’s worth moving on to the rules for compiling names according to IUPAC.

IUPAC nomenclature: rules for the formation of names

First, it is necessary to find in the hydrocarbon structure the carbon chain that is longest and contains the maximum number of substituents. Then you need to number the C atoms of the chain, starting from the end to which the substituent is closest.

Secondly, the base is the name of an unbranched saturated hydrocarbon, which, in terms of the number of C atoms, corresponds to the main chain.

Thirdly, before the base it is necessary to indicate the numbers of the locants near which the substituents are located. The names of the substituents are written after them with a hyphen.

Fourthly, in the case of the presence of identical substituents at different C atoms, the locants are combined, and a multiplying prefix appears before the name: di - for two identical substituents, three - for three, tetra - four, penta - for five, etc. Numbers must be separated from each other by a comma, and from words by a hyphen.

If the same C atom contains two substituents at once, the locant is also written twice.

According to these rules, the international nomenclature of alkanes is formed.

Newman projections

This American scientist proposed special projection formulas for graphical demonstration of conformations - Newman projections. They correspond to forms A and B and are presented in the figure below.

In the first case, this is an A-occluded conformation, and in the second, it is a B-inhibited conformation. In position A, the H atoms are located at a minimum distance from each other. This form corresponds most great importance energy, due to the fact that the repulsion between them is greatest. This is an energetically unfavorable state, as a result of which the molecule tends to leave it and move to a more stable position B. Here the H atoms are as far apart as possible from each other. Thus, the energy difference between these positions is 12 kJ/mol, due to which the free rotation around the axis in the ethane molecule, which connects the methyl groups, is uneven. After entering an energetically favorable position, the molecule lingers there, in other words, “slows down.” That is why it is called inhibited. Result - 10 thousand ethane molecules are in the inhibited form of conformation under the condition room temperature. Only one has a different shape - obscured.

Obtaining saturated hydrocarbons

From the article it has already become known that these are alkanes (their structure and nomenclature were described in detail earlier). It would be useful to consider ways to obtain them. They stand out from these natural sources, like oil, natural, coal. Synthetic methods are also used. For example, H₂ 2H₂:

1. Hydrogenation process CnH₂n (alkenes)→ CnH₂n+2 (alkanes)← CnH₂n-2 (alkynes).
2. From a mixture of C and H monoxide - synthesis gas: nCO+(2n+1)H₂→ CnH₂n+2+nH₂O.
3. From carboxylic acids (their salts): electrolysis at the anode, at the cathode:

• Kolbe electrolysis: 2RCOONa+2H₂O→R-R+2CO₂+H₂+2NaOH;
• Dumas reaction (alloy with alkali): CH₃COONa+NaOH (t)→CH₄+Na₂CO₃.

1. Oil cracking: CnH₂n+2 (450-700°)→ CmH₂m+2+ Cn-mH₂(n-m).
2. Gasification of fuel (solid): C+2H₂→CH₄.
3. Synthesis of complex alkanes (halogen derivatives) that have fewer C atoms: 2CH₃Cl (chloromethane) +2Na →CH₃- CH₃ (ethane) +2NaCl.
4. Decomposition of methanides (metal carbides) by water: Al₄C₃+12H₂O→4Al(OH₃)↓+3CH₄.

Physical properties of saturated hydrocarbons

For convenience, the data is grouped into a table.

Conclusion

The article examined such a concept as alkanes (structure, nomenclature, isomerism, homologous series, etc.). A little is said about the features of radial and substitutive nomenclatures. Methods for obtaining alkanes are described.

In addition, the article lists in detail the entire nomenclature of alkanes (the test can help to assimilate the information received).