Hydrocarbons are compounds of carbon with hydrogen that do not contain other elements. Hydrocarbon classification
What are hydrocarbons? How are they classified? What features have? Let's try together to find answers to the questions.
Hydrocarbons are hydrogen and carbon. They are considered organic compounds in basic chemistry.
Depending on the state of the bond between the carbon of the main chain, all CxHattaken to subdivide into several types. Single carbon-hydrogen compounds are characteristic of saturated hydrocarbons.
Limit hydrocarbons are compounds having the general formula CPH2p + 2. Among their features we can mention the absence of a closed structure, as well as single (simple) connections.They are called acyclic compounds in organic chemistry.
A typical representative of this class is methane - CH.4. It is he who begins the homologous series of alkanes, possesses all the properties inherent in the other representatives of paraffins.
The first representatives of this class of hydrocarbons are gaseous substances with low solubility in water, a specific odor.
Among the basic chemical properties possessed by representatives of the homologous series of alkanes, we single out a radical substitution.
Halogenation occurs at elevated temperatures or the presence of ultraviolet radiation. The reaction proceeds in several stages, characterized by the gradual replacement of hydrogen atoms with halogen. The properties of hydrocarbons of a number of methane are explained by the saturation of the bond between carbon atoms. They are not capable of entering into addition reactions, while they are excellent in oxygen in the air to form carbon dioxide, water vapor, and release enough heat energy.
Among the main branches of application of representatives of this class of hydrocarbons we will single out the use as fuel,as well as the option of raw materials for the production of many other organic compounds.
Unsaturated hydrocarbons are compounds that have one or more multiple (unsaturated) bonds between carbon atoms. Alkenes have the general formula CPH2n. A typical representative of this class is ethylene.
These natural hydrocarbons are part of the oil. Considering that the molecule contains a double bond, addition reactions are characteristic of alkenes. For example, they can enter into halogenation, hydration.
If the double bond is located in the first position, for example, in butene-1, the addition of hydrogen halide and hydration (reaction with water) proceed according to the Markovnikov rule. Its essence consists in the fact that during hydrohalogenation and hydration hydrogen is attached to the carbon atom that is maximally saturated with it.
A hydroxyl group or halogen atom is attached to a C atom that is not saturated with hydrogen. A qualitative response to unsaturated (double) bond is the bleaching of bromine water or potassium permanganate.
Such hydrocarbons are cyclic compounds that are interclass isomers for alkenes. They have the general formula CPH2nsingle connections.Given that this class is characterized by a closed structure, they enter into addition reactions, accompanied by the destruction of a closed cycle, turning into saturated alkanes. The main sources of such compounds are natural and associated gas, oil. Despite the cyclic structure, in sp3 hybridization molecules, the valence angle is 109 ° 28 '.
What else is characterized by organic chemistry? Hydrocarbons of this class have the general formula CPH2n-2. All representatives of diene hydrocarbons have two double bonds. The unsaturation of the dienes determines their basic chemical properties. By analogy with alkenes, diene compounds enter into addition reactions.
As those chemical reactions that are characteristic of these compounds, we note polymerization. The initial monomer in the process is the representative of the dienes, and the interaction product will be synthetic rubber. When sulfur is added to the resulting polymer, vulcanization occurs, accompanied by the formation of rubber.
For these unsaturated organic compounds characterized by the general formula CPH2n-2, it is possible to note the presence of a triple bond between carbon atoms. If it is located after the first carbon atom, the qualitative reaction to its presence is the substitution with the complex compound of silver.
As well as for alkenes, dienes, alkynes easily join a triple bond. They are characterized by hydrogenation, hydrohalogenation, halogenation, hydration reactions.
Benzene is the first representative of this class. It has the general formula CPH2p-6. Unlike all other hydrocarbons, this compound has an aromatic ring. Free electrons of each carbon atom take part in its formation. Three electrons of C form hybrid clouds, and the fourth electron does not undergo hybridization. It forms the aromatic ring, which is evenly distributed throughout the molecule. The uniform distribution of the ring by structure explains its chemical stability. Benzene itself enters the substitution and addition only under harsh conditions.
Toluene, which is its homologue, is characterized by a certain shift in the electron density, therefore it has a higher capacity for substitution.The hydrocarbon radical is a first-type orientant, the incoming substituents (halogen, nitro group) occupy ortho-, para-positions.
Regardless of what features of the structure are different representatives of hydrocarbons, they have a certain number of carbon atoms and hydrogens in their composition. There is a definite tendency to change the physical properties of C representatives.xHat. The first representatives of any class have a gaseous state, as the relative molecular weight increases, a systematic transition in a liquid is observed, then in a solid form.