Difference Between Alcohols and Phenols

Main Difference

The main difference between alcohols and phenols is that alcohol’s hydroxyl group is attached to a saturated carbon atom, whereas phenol’s hydroxyl group is directly bonded to a carbon molecule of an aromatic ring.

Alcohols vs. Phenols

Hydroxyl group of alcohols are attached to a saturated carbon atom, whereas the hydroxyl group of phenols is directly bonded to a carbon molecule of an aromatic ring. By nature of alcohols, they are usually aliphatic hydrocarbons, while regarding nature of phenols they are aromatic hydrocarbons. Aliphatic alcohols are less acidic than phenol; on the other hand, phenols are always acidic and must be diluted before use. Alcohols are used in pharmaceuticals, ink, in the beverage industry, and many more; on the contrary, phenols are generally used as antiseptic agents in wounds. Alcohols are denoted as R-OH, where R represents alkyl group; conversely, phenols are denoted as ph-OH where ph represents the phenolic ring. Alcohols are typically a group in compounds, whereas phenols are a specific compound. Colorless liquids of alcohols are generally lower alcohols; on the other hand, phenols are crystalline colorless deliquescent solids. Alcohols are neutral that’s why they show no impact on litmus paper; on the flip side, as phenols are acidic so turn litmus paper into the red. By reacting with aqueous NaOH, alcohols show no reaction as a result, but when the reaction occurs between phenols and NaOH, it produces phenoxide ions as a result. Different types of alcohols are vermouth, vodka, gin, whiskey, brandy, cognac, beer, rum, and port-wine; on the contrary, different types of phenols are phenol-formaldehyde, toluene, benzene, aniline, nitrophenol, anisole, ferulic acid, Gallic acid, and catechol.

Comparison Chart

AlcoholsPhenols
Alcohols are organic compounds whose atoms contain one or more hydroxyl groups which are directly bonded to a carbon atom.Phenols are mixtures consisting of a hydroxyl group which is bonded directly to a hydrocarbon group of an aromatic ring.
Nature
Aliphatic hydrocarbonsAromatic hydrocarbons
Acidity
Aliphatic alcohols are less acidic than phenolAlways acidic and must be diluted before use
Applications
Used in pharmaceuticals, ink, in the beverage industry, and many moreGenerally used as antiseptic agents in wounds
Denotation
Denoted as R-OH, where R represents an alkyl groupDenoted as ph-OH where ph represents the phenolic ring
Type
A group in compoundsA specific compound
Color
Colorless liquidsCrystalline colorless deliquescent solids
Litmus Paper Test
Show no impact on litmus paperTurn litmus paper into red
Reaction With NaOH
Show no reactionProduces phenoxide ions
Different Types
Vermouth, vodka, gin, whiskey, brandy, cognac, beer, rum, and port-winePhenol formaldehyde, toluene, benzene, aniline, nitrophenol, anisole, ferulic acid, Gallic acid, and catechol

What are Alcohols?

Alcohols are organic compounds whose atoms contain one or more hydroxyl groups which are directly bonded to a carbon atom. So, alcohols are molecules that have one or more hydroxyl groups. Alcohols are generally classified into three categories based on the structure of its molecules: primary, secondary, and tertiary alcohols. Alcohols are denoted as R-OH, where R represents alkyl group, and it is a hydrocarbon group. Methanol is the simplest alcohol and R is its methyl group. Alcohols have high boiling points when compared with analogous alkanes. When carbon atoms of molecules are increased in number then the boiling point of alcohols also increases. Alcohols form hydrogen bonds with other alcohol molecules also due to the presence of more than one hydroxyl group forming intermolecular attractions. Alcohols are soluble in water with simple structures present in them. Though, with the increase of alkyl group length of alcohol, the solubility decreases. But alcohols can be highly poisonous with concentrations of solutions. Different types of alcohols are vermouth, vodka, gin, whiskey, brandy, cognac, beer, rum, and port-wine.

What are Phenols?

Phenols are mixtures consisting of a hydroxyl group which is bonded directly to a hydrocarbon group of an aromatic ring. Due to this linkage, phenols are also considered as an aromatic compound. Phenols are more acidic than alcohols so turn litmus paper into the red. Phenols are denoted as ph-OH where ph represents the phenolic ring. Diluted phenol is excessively strong to be used on biological tissues. Phenols have a pungent smell and have a low melting point. Phenols are best known for their antiseptic uses in surgeries and pharmaceutical industries. But highly concentrated phenols can burn healthy tissues. Phenols are soluble in most organic solvents such as alcohols, ketones, acids, ether, and hydrocarbons. Different types of phenols are phenol-formaldehyde, toluene, benzene, aniline, nitrophenol, anisole, ferulic acid, Gallic acid, and catechol.

Key Differences

  1. Hydroxyl group of alcohols are attached to a saturated carbon atom, whereas the hydroxyl group of phenols is directly bonded to a carbon molecule of an aromatic ring.
  2. Alcohols are aliphatic hydrocarbons, while phenols are aromatic hydrocarbons.
  3. Aliphatic alcohols are usually less acidic; on the other hand, phenols are always acidic and must be diluted before use.
  4. Alcohols are used in pharmaceuticals, ink, in the beverage industry, and many more; on the contrary, phenols are generally used as antiseptic agents in wounds.
  5. Alcohols are denoted as R-OH, where R represents alkyl group; conversely, phenols are denoted as ph-OH where ph represents the phenolic ring.
  6. Alcohols are typically a group in compounds, whereas phenols are a specific compound.
  7. Lower alcohols are generally colorless liquids of alcohols; on the other hand, phenols are crystalline colorless deliquescent solids.
  8. Alcohols show no impact on litmus paper; on the flip side, phenols turn litmus paper into the red.
  9. When aqueous NaOH reacts with alcohols, they show no reaction, but when a reaction occurs between phenols and NaOH, it produces phenoxide ions.
  10. Different types of alcohols are vermouth, vodka, gin, whiskey, brandy, cognac, beer, rum, and port-wine; on the contrary, different types of phenols are phenol-formaldehyde, toluene, benzene, aniline, nitrophenol, anisole, ferulic acid, Gallic acid, and catechol.

Conclusion

Above discussion concludes that alcohols are colorless liquids and its hydroxyl group is attached to a saturated carbon atom, whereas phenols colorless crystalline solids and its hydroxyl group is directly bonded to a carbon molecule of an aromatic ring.

Harlon Moss

Harlon currently works as a quality moderator and content writer for Difference Wiki. He graduated from the University of California in 2010 with a degree in Computer Science. Follow him on Twitter @HarlonMoss

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