What is the Difference Between Polycyclic and Polynuclear Aromatic Hydrocarbons?
🆚 Go to Comparative Table 🆚Polycyclic aromatic hydrocarbons (PAHs) and polynuclear aromatic hydrocarbons (PNAs) are terms used to describe the same class of organic compounds, which are often used interchangeably. These compounds are characterized by multiple aromatic rings, containing only carbon and hydrogen, and are produced by incomplete combustion or high-pressure processes. They are solids with low volatility at room temperature, have relatively high molecular weights, and are relatively insoluble in water.
Both PAHs and PNAs are composed of large organic molecules with multiple aromatic rings, and they have similar properties and characteristics. The term "polycyclic" refers to the presence of multiple rings, while "polynuclear" refers to the presence of many atoms. Some sources define PAHs as having multiple aromatic rings, precluding benzene from being considered a PAH, while others consider naphthalene to be the simplest PAH. In summary, the key difference between the two terms lies in their description, with "polycyclic" focusing on the multiple rings and "polynuclear" focusing on the many atoms. However, both terms refer to the same class of compounds.
Comparative Table: Polycyclic vs Polynuclear Aromatic Hydrocarbons
Polycyclic aromatic hydrocarbons (PAHs) and polynuclear aromatic hydrocarbons (PNAs) are both classes of organic compounds that consist of aromatic rings containing only carbon and hydrogen atoms. While the terms PAH and PNA are often used interchangeably, they have subtle differences in their definitions. Here is a table comparing the two classes of compounds:
Feature | Polycyclic Aromatic Hydrocarbons (PAHs) | Polynuclear Aromatic Hydrocarbons (PNAs) |
---|---|---|
Definition | Compounds that consist of three or more fused benzene rings | Compounds that contain two or more fused aromatic rings, regardless of the number of rings |
Production | Produced by incomplete combustion or high-pressure processes | Produced by natural processes, such as incomplete combustion or high-pressure processes |
Occurrence | Found in coal, crude oil, gasoline, and various foods | Found in coal, crude oil, gasoline, and various foods |
Structure | Typically have three or more fused benzene rings | Can have two or more fused aromatic rings |
Properties | Solids with low volatility, high molecular weights, soluble in many organic solvents, relatively insoluble in water, and can be photo-oxidized and degraded | Properties depend on the specific structure and number of rings |
In summary, PAHs consist of three or more fused benzene rings, while PNAs can have two or more fused aromatic rings. Both classes of compounds share similar production methods and occurrences, but their properties can vary depending on the specific structure and number of rings.
- Aliphatic vs Aromatic Hydrocarbons
- Homonuclear vs Heteronuclear Aromatic Compounds
- Homocyclic vs Heterocyclic Compounds
- Carbocyclic vs Heterocyclic
- Alicyclic vs Aromatic Compounds
- Alternant vs Nonalternant Hydrocarbons
- Naphthenes vs Aromatics
- Aromatic vs Aliphatic
- Aliphatic vs Aromatic Carboxylic Acid
- Naphthalene vs Anthracene
- Acyclic vs Cyclic Organic Compounds
- Aromatic vs Aliphatic Aldehydes
- Hydrocarbons vs Carbohydrates
- Naphthalene vs p-Dichlorobenzene
- Chlorobenzene vs Chlorocyclohexane
- Anthracene vs Phenanthrene
- Benzene vs Cyclohexane
- Cyclohexane vs Cyclohexene
- Aliphatic vs Aromatic Amines