In the article we will consider the preparation of cycloalkanes and the features of their structure. Let's try to explain the characteristic properties of these substances, based on the features of their structure.
Structure
To begin with, let's analyze the structure of the named class of organic hydrocarbons. All cyclic compounds are divided into heterocyclic and carbocyclic species.
The second group has three carbon atoms inside the closed cycle. Heterocyclic compounds, in addition to carbon, also contain atoms of sulfur, oxygen, phosphorus, and nitrogen in their molecules.
There is a division of carbocyclic compounds into aromatic and alicyclic substances.
Alicyclic substances
These include cycloalkanes. The chemical properties and production of these substances are determined precisely by the closed structure of this class of hydrocarbons.
Alicyclic substances are those that have one or more non-aromatic cycles. The preparation and use of cycloalkanes is considered in terms of their relationship to alicyclic compounds.
Classification
The simplest representative of this classhydrocarbon is cyclopropane. It has only three carbon atoms in its structure. Representatives of this homologous series are also called paraffins. In terms of their chemical and physical properties, they are similar to saturated hydrocarbons. Molecules contain single bonds formed by hybrid orbitals. In cycloalkanes, the type of hybridization is sp3.
The total composition of the class is expressed by the formula СНН2н. These compounds are interclass isomers of ethylene hydrocarbons.
According to the modern international substitution nomenclature, when naming representatives of this class, the prefix "cyclo" is added to the corresponding hydrocarbon in terms of the number of atoms. In this case, for example, cyclohexane, cyclopentane are obtained. The rational nomenclature provides names according to the number of closed methylene groups CH2. Due to this, cyclopropane will be called trimethylene, and cyclobutane - tetramethylene.
This class of organic substances is characterized by structural isomerism regarding the number of carbon atoms in the cycle, as well as optical isomerism.
Education options
Now let's look at how receiving works. Cycloalkanes can be obtained in several ways, depending on which starting material is chosen to carry out the chemical transformation. We will analyze the main options for the synthesis of paraffins.
So what's it like getting them? Cycloalkanes are formed by cyclization of diahalogen derivatives of saturated hydrocarbons. In a similar chemical way,four- and three-membered cycles. For example, cyclopropane. Let us consider its preparation in more detail - cycloalkanes, which are the first representatives of this homologous series, are formed by the action of metallic magnesium or zinc on the dihalogen derivative of the corresponding alkane.
And how can five-membered and six-membered cyclic compounds be formed, how are they obtained? It is rather difficult to create cycloalkanes with such a number of carbon atoms in the structure, since due to the conformation there will be a problem with the cyclization of the molecule. This phenomenon is explained by free rotation in the C-C bond, which significantly reduces the likelihood of obtaining a cyclic compound. For the formation of these representatives of cycloalkanes, 1, 2- or 1, 3-dihalogen derivatives of the corresponding alkane act as starting materials.
Among the methods for the synthesis of paraffins, we also highlight the process of decarboxylation of dicarboxylic acids and s alts. Five- and six-membered cycloalkanes are obtained by intermolecular condensation.
And among the special methods of their formation, we note the reaction between alkenes and carbenes, the reduction of oxygen-containing derivatives of cyclocompounds.
Chemical properties
All possible ways of obtaining cycloalkanes and their interaction are determined by the peculiarities of the chemical structure. Given the presence of a cyclic structure, among the main chemical properties of cycloalkanes, we single out the reactions of hydrogen addition (hydrogenation), its elimination (dehydrogenation).
For reactionsa catalyst is used, in the role of which platinum, palladium can act. The interaction is carried out at an elevated temperature, its value depends on the size of the cycle. When a cyclic hydrocarbon molecule is exposed to UV radiation, a chlorination reaction (addition of chlorine) can be carried out.
Like all representatives of organic compounds, cycloalkane is able to enter into a combustion reaction, forming after interaction carbon dioxide, water vapor. This reaction refers to exothermic processes, as it is accompanied by the release of a sufficient amount of heat.
Conclusion
Paraffins are closed hydrocarbon compounds formed from dihalogenated alkanes or other organic compounds. The features of their structure determine the basic chemical properties of cycloalkanes and their areas of application. They are mainly used in organic synthesis to obtain oxygen-containing organic substances.
