The definition “destruction” is disrupting. This is the general name for the processes occurring
with the rupture of chemical bonds of macromolecules.
Thermal destruction of hydrocarbons is their splitting, disintegration into parts under the
influence of temperatures. However, during the thermal destruction in over the range
temperature up 932 to 1 652 ° F, there are not only decomposition reactions of the substance
occur, but there are also reactions of its synthesis at the same time.
All decomposition and compound reactions are equivalent and are characterized by the change of
the number of molecules during the reaction. This leads to the strong influence of the
concentration of reagents or the pressure in the system on the reaction rate and on the equivalent
position.
The decomposition reactions of the substance proceed with an increase in the volume of the
system, the number of molecules in the course of the reaction and the absorption of heat.
Obviously, that in order to break the chemical bonds in a molecule (reactions are groups – these
are reactions of destruction of a molecule), it is necessary to spend a certain amount of energy
(for example, heat). Thus, the reactions of the first group are endothermic reactions. Often,
instead of one volume of the initial substance, two volumes of product substances are formed.
The synthesis reaction of a substance proceeds with a decrease in the volume of the number of
molecules during the reaction. These reactions can be attributed to the reactions of the synthesis
of a substance. Compound reactions are usually accompanied by a significant release of energy.
The reason is that during the synthesis reaction weaker bonds are broken and stronger bonds are
formed. The reactions of the second group are exothermic reactions. For example,
polymerization reactions.
For the processes associated with the release or absorption of heat, the effect of temperatures on
the change in the free energy of the system is characterized by the Le Chatelier principle.
According to Le Chatelier’s rule, as the temperature rises for exothermic reactions, the equivalent
shifts to the left and right – for the endothermic reactions. Therefore, for endothermic reactions it
is necessary to increase the process temperature. Such reactions are called high-temperature and
they are carried out at temperatures above 600 K. Hence, for exothermic reactions, the process
temperature must be lowered and carried out at temperatures below 600 K.Since the reactions of
both groups proceed with a change in volume, a change in external pressure is of great
importance. An increase in pressure for reactions proceeding with a decrease in volume leads to
a shift in equivalent to the right. On the contrary, for the decomposition reactions or any other
reactions proceeding with an increase in volume, a shift of equilibrium to the right occurs with a
decrease in pressure.