Difference Between Phenols and Polyphenols

The key difference between phenols and polyphenols is that phenol is an aromatic compound containing a benzene ring substituted with a hydroxyl group whereas polyphenols are aromatic compounds containing more than one phenolic group.

Both phenols and polyphenols contain a hydroxyl group (-OH) as their functional group. These are aromatic organic compounds.

1. Overview and Key Difference
2. What are Phenols
3. What are Polyphenols
4. Side by Side Comparison – Phenols vs Polyphenols in Tabular Form
5. Summary

What are Phenols?

Phenols are organic compounds having the chemical formula HO-C₆H₅. These are aromatic structures because they have a benzene ring. Phenol can be made as a white solid that is volatile. This compound is a mildly acidic compound due to the presence of a removable proton at the hydroxyl group of phenol. Also, we have to handle phenol solutions with care in order to prevent burns.

Figure 01: Structure of Phenol

Phenol can be produced via the extraction from coal tar. The main method of production is from the petroleum-derived feedstock. The process of the production of phenol is the “cumene process”. This white solid of phenol has a sweet odour which is tarry. Moreover, it is soluble in water due to its polarity.

Phenol tends to undergo electrophilic substitution reactions because the lone electron pairs of the oxygen atom are donated to the ring structure. Therefore, many groups, including halogens, acyl groups, sulfur-containing groups, etc. can be substituted to this ring structure. Phenol can be reduced to benzene via distillation with zinc dust.

What are Polyphenols?

Polyphenols are large aromatic compounds containing more than one phenolic group. These compounds occur as natural or can be made as a synthetic compound. Sometimes, there can be semi-synthetic forms as well. Polyphenols can be found often as very large compounds. Moreover, these compounds tend to get deposited in cell vacuoles. The molecular weight of polyphenols allows them to rapidly diffuse across cell membranes.

Figure 02: Plant-derived Polyphenol, Tannic Acid

Furthermore, polyphenols have heteroatomic substituents other than hydroxyl groups. Ether groups and ester groups are common. When considering the chemical properties of these molecules, they have UV/visible absorptivity due to the presence of aromatic groups. They also have autofluorescence properties. In addition, they are very reactive to oxidation.

When considering the uses of these compounds, people traditionally use it as dyes. Moreover, there are some biological uses, such as:

The release of growth hormone in plants
Suppression of growth hormone in plants
Act as signalling molecules in ripening and other growth processes
Provide prevention from microbial infections.

What is the Difference Between Phenols and Polyphenols?

The key difference between phenols and polyphenols is that phenol is an aromatic compound containing a benzene ring substituted with a hydroxyl group whereas polyphenols are aromatic compounds containing more than one phenolic group. Moreover, phenols contain one phenolic group per molecule while polyphenols contain more than one phenolic group per molecule.

The following table summarizes the difference between phenols and polyphenols.

Summary – Phenols vs Polyphenols

Both phenols and polyphenols contain a hydroxyl group (-OH) as their functional group. These are aromatic organic compounds. The key difference between phenols and polyphenols is that phenol is an aromatic compound containing a benzene ring substituted with a hydroxyl group whereas polyphenols are aromatic compounds containing more than one phenolic group.

Reference:

1. “Phenol | Definition, Structure, Uses, & Facts”. Encyclopedia Britannica, 2020, Available here.
2. “Phenol”. Ncbi.Nlm.Nih.Gov, 2020, Available here.
3. “Polyphenol – An Overview | Sciencedirect Topics”. Com, 2020, Available here.

Image Courtesy:

1. “Phenol2” By NEUROtiker – Own work (Public Domain) via Commons Wikimedia
2. “Tannic acid” By en:User_talk:Ronhjones – Own work (Public Domain) via Commons Wikimedia