What are Hydrocarbons?
Hydrocarbons
What are Hydrocarbons?
Hydrocarbons are organic compounds whose molecular structure is formed from the union between hydrogen and carbon atoms.
The basic formula for hydrocarbons is as follows: C x H y .
These organic compounds can be found in different states of matter: liquid, gaseous (natural gas or by condensation) and eventually solid.
The oil (liquid) and natural gas (gaseous) are hydrocarbon mixtures. Hydrocarbons are the source from which other organic substances, such as fossil fuel, are derived.
Characteristics of hydrocarbons
- They are organic compounds made up only of hydrogen and carbon atoms.
- They are not usually biodegradable.
- They are hydrophobic, that is, insoluble in water.
- They are lipophilic, that is, soluble in organic solvents.
- When combustion is optimal or complete, they produce water and carbon dioxide.
- When combustion is inadequate or incomplete, they produce water and carbon or carbon monoxide (soot).
Classification of hydrocarbons
There are two main types of hydrocarbons. Let's look at each one separately.
Aromatic hydrocarbons or arenes
They are cyclic organic compounds characterized by having a common nucleus, known as benzene. It can be of two kinds:
- Monocyclic : those in which a hydrogen molecule of the benzene ring is replaced by side chains, that is, by hydrocarbon residues. For example, Methylbenzene or Toluene (C 6 H 5- CH 3 ).
- Polycyclic : they are those that contain two or more benzene nuclei.
Aliphatic hydrocarbons
They are essentially made up of hydrogen and carbon and do not have an aromatic character. Its chains are open, and can be both linear and branched. Aliphatic hydrocarbons are subdivided into:
- Saturated hydrocarbons or alkanes : they are those whose carbon bonds are simple. Alkanes contain single carbon-carbon bonds. The general formula for alkanes is as follows: (C n H 2n + 2 ) For example, ethane.
- Unsaturated hydrocarbons : are those that contain carbon-carbon double or triple bonds. They are part of this group:
- Alkenes or olefins: with carbon-carbon double bonds (CH 2 = CH 2 ). For example: Limonene (from citrus oils).
- Alkynes or acetylenes (with carbon-carbon triple bonds). For example: ethyne (HC≡CH).
Where do hydrocarbons come from?
Hydrocarbons are usually found in reservoirs, deposits or reservoirs at the subsoil level, either on the land platform or on the marine platform.
The process that results in obtaining hydrocarbons consists of four stages. Let's get to know them.
1. Deep sedimentation
Hydrocarbons are formed from the decomposition and thermal transformation of sediments of organic matter (algae, plant remains, animals) deposited at great depth, which are contained in the so-called mother rock , that is, in the rocky base of the soil. .
2. Heating and pressure
The concentration of temperature and pressure exerted on organic matter over the centuries causes it to transform into liquid (oil) or gas. The transformation of organic matter depends on the presence of the bedrock.
3. Migration of hydrocarbons from bedrock to storage rock
Once transformed, the hydrocarbons migrate into the pores of the so-called storage rocks , that is, sand and fragmented rocks that can absorb and expel the fluids. Warehouse rocks have two characteristics: porosity and permeability. It is not, therefore, a concave deposit as is usually imagined.
4. Retention by oil trap or impermeable rocks
The geometric shape of a storage rock where the fluid is trapped is called an oil trap . The trap is covered by a seal rock that prevents the hydrocarbon in question from being expelled to the surface.
Use and importance of hydrocarbons
Other important substances are formed from hydrocarbons, without which modern and industrial life as we know it would not be possible.
In fact, hydrocarbons have many uses both at an industrial level and in everyday life, since from them we obtain:
- Energy resources: refers to fuels from hydrocarbons that allow the mobilization of industry, transport, agriculture and electricity for domestic consumption. This is equivalent to almost 80% of the electricity generation in the world.
- Raw materials: useful in the manufacture of products such as plastic, inks, rubber, synthetic fibers for textiles, detergents, pencils, insecticides and chemical products in general.
- Specialty Products - These include asphalt, engine and equipment greases, lubricants, paraffins, etc.
Substituted hydrocarbons
It refers to those compounds that, although they share the same basic structure of a hydrocarbon, also contain atoms of other chemical elements. This section of the molecule with these characteristics is called a functional group.
For example:
Halogenated compounds such as those included in pesticides, repellants, solvents or refrigerants.