OBI - Petroleum Hydrocarbons

Hydrocarbons - petroleum

A hydrocarbon is one of nature's most simple and primitive organic compounds, and contains only carbon and hydrogen atom. The largest source of hydrocarbons is petroleum crude oil.

Crude oil is a complex mixture of thousands of different chemical compounds. Many people talk about all hydrocarbons like they are one and the same, they are not. Crude oil hydrocarbons are very different from the hydrocarbons found in plants.

Saturates	Aromatics	Asphaltenes	Resins
The largest group is normally those with only single carbon-carbon bonds. Generally, straight-chain alkanes degrade more quickly than branched alkanes or cycloalkanes. Alkanes - have at least one carbon-carbon double bond.	The most common aromatics are those that contain a benzene ring. Poly nuclear aromatic hydrocarbons (PAH's) a compound having two or more benzene rings fused together. Basically, the more benzene rings the harder it is to degrade the hydrocarbon.	Contain compounds that are either very slow to degrade or not biodegradable. Generally contains compounds that degrade very slowly or are either not biodegradable. Example - tar balls.	Include petroleum compounds containing nitrogen, sulfur, and/or oxygen. Subject to limited degradation.
Alkenes - have at least one carbon-carbon triple bond (not commonly found in petroleum hydrocarbons).	Monoaromatics - primary structure has at least one benzene ring made up of six atoms with alternating single & double bonds.

Saturates

Aromatics

Asphaltenes

Resins

The largest group is normally those with only single carbon-carbon bonds.

Generally, straight-chain alkanes degrade more quickly than branched alkanes or cycloalkanes.

Alkanes - have at least one carbon-carbon double bond.

The most common aromatics are those that contain a benzene ring.

Poly nuclear aromatic hydrocarbons (PAH's) a compound having two or more benzene rings fused together.

Basically, the more benzene rings the harder it is to degrade the hydrocarbon.

Contain compounds that are either very slow to degrade or not biodegradable.

Generally contains compounds that degrade very slowly or are either not biodegradable.

Example - tar balls.

Include petroleum compounds containing nitrogen, sulfur, and/or oxygen.

Subject to limited degradation.

Alkenes - have at least one carbon-carbon triple bond (not commonly found in petroleum hydrocarbons).

Monoaromatics - primary structure has at least one benzene ring made up of six atoms with alternating single & double bonds.

The potential for biodegradation of PAH's declines as the number of benzene rings in the chemical structure increases.

PAHs are often contaminants of concern because of their chemical and toxicological properties. PAHs tend to be immobile and highly persistent in the environment, with relatively high accumulation rates and toxicity.