How Is Cresol Produced and Used in Chemistry?
Cresols can be defined as the organic compounds that are methyl phenol. The cresols are a naturally occurring and manufactured group of aromatic organic compounds that can be defined as phenols. The cresols can be categorised as either liquid or solid depending on their melting point that is similar to the room temperature.
The cresols, like other forms of phenols, oxidise slowly when they are exposed to impurities and oxygen. This often gives the cresols samples a brownish-red to a yellowish tint. The odour characteristics of the cresols are of the other simple phenols which have a smell of coal tar. Cresol refers to the structure, being phenols as well as a traditional source of creosote. Cresols also have other names like hydroxytoluene.
The Structure of the Cresol
In the chemical structure of cresols, the molecule has the methyl group which is substituted on the phenyl ring. The three forms of cresol that exist are meta-cresol, para-cresol, and ortho-cresol. These forms either exist completely separately or as a form of the mixture, and it is also referred to as the cresol or the tricresol.
The Production of the Cresols
Approximately half of the cresols supply in the world is extracted from coal tar. The rest of it is manufactured by hydrolysis of the chlorotoluenes or through related sulfonates. The alternate method entails the methylation of the phenol using methanol over the solid acid catalyst which often comprises alumina or magnesium oxide. The temperatures that range over 300 degrees centigrade are considered typical. Anisole is converted to the cresols according to the given conditions.
Health Effects
When the compounds of cresol are ingested, applied to the skin, or inhaled then they might be harmful. Some of the effects or impact it has on people include burning of skin, throat, mouth, and eyes. People also experience vomiting and abdominal pain, irritation, heart damage, anaemia, liver and kidney damage, facial paralysis, coma, and sometimes even death.
Breathing high levels of this compound for a short period can result in nose and throat irritation. Ingesting high levels of this compound also causes throat and mouth burns, vomiting, kidney problems, abdominal pain, and adverse effects on blood and the nervous system. When high levels of the cresol compounds come in contact with the skin, it causes damage to blood, liver, kidneys, lungs, brain, and causes burning of the skin.
FAQs on Cresol: Meaning, Structure & Applications
1. What exactly is cresol?
Cresol refers to a group of aromatic organic compounds that are chemically known as methylphenols. They consist of a phenol structure (a benzene ring bonded to a hydroxyl group) with an additional methyl group attached to the ring. Depending on the position of this methyl group, cresol exists as three different isomers.
2. What are the different types or isomers of cresol?
Cresol has three structural isomers, which differ in the position of the methyl group (–CH₃) relative to the hydroxyl group (–OH) on the benzene ring. These are:
- ortho-Cresol (o-cresol): The methyl group is at position 2, adjacent to the hydroxyl group.
- meta-Cresol (m-cresol): The methyl group is at position 3.
- para-Cresol (p-cresol): The methyl group is at position 4, opposite the hydroxyl group.
3. What is the IUPAC name for cresol?
Since cresol is a common name for a group of isomers, each isomer has its own specific IUPAC name based on standard nomenclature rules. The IUPAC names are:
- o-cresol is 2-methylphenol.
- m-cresol is 3-methylphenol.
- p-cresol is 4-methylphenol.
4. What are some common real-world examples and applications of cresol?
Cresols are valuable chemical intermediates and are used in various applications, such as:
- Disinfectants and Antiseptics: They are a key ingredient in household disinfectants like Lysol due to their ability to destroy bacterial cell membranes.
- Wood Preservatives: They protect wood from fungal and insect decay.
- Chemical Synthesis: Cresols are precursors for manufacturing other important chemicals, including plastics, pesticides, dyes, and pharmaceuticals.
- Antioxidants: They are used to produce antioxidants like BHT (butylated hydroxytoluene), which prevents spoilage in foods and other materials.
5. How is the structure of cresol different from phenol?
The primary difference is the presence of a methyl group (–CH₃). While phenol consists of just a hydroxyl group (–OH) attached to a benzene ring, cresol has both a hydroxyl group and a methyl group. Therefore, cresols are considered substituted phenols or derivatives of phenol.
6. Why are cresols acidic, and how does their acidity compare to phenol?
Cresols are acidic because the hydroxyl group can donate a proton (H⁺), and the resulting negative charge on the oxygen is stabilized by delocalisation across the benzene ring. However, the methyl group is an electron-donating group. This group pushes electron density into the ring, which slightly destabilizes the negative charge on the oxygen atom. As a result, cresols are generally less acidic than phenol.
7. What is the mechanism that makes cresol an effective disinfectant?
Cresol functions as a disinfectant by targeting the fundamental components of microbial cells. Its primary mechanism of action is the disruption of the bacterial cell membrane. It also penetrates the cell and denatures essential proteins and enzymes, which halts cellular processes and ultimately leads to the death of the microorganism.
8. Is cresol considered toxic or harmful to humans?
Yes, in concentrated forms, cresol is toxic and corrosive. Direct contact can cause severe skin and eye irritation, while inhalation can lead to respiratory tract damage. If ingested or absorbed in high amounts, it can be harmful to the liver, kidneys, and central nervous system. For this reason, its use in consumer products is always in very dilute and carefully controlled concentrations to ensure safety.
