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| Synonyms: 2-Methylphenol 1-Hydroxy-2-methylbenzene o-Cresylic acid 2-Cresol Molecular Formula:C₇H₈O Molecular Weight: 108.14 HS Code: 2907121200 Grade: Industrial grade Fragrance Grade99%；99.5% Hazard Class:Class 6.1+Class8 | |||||||||
95-48-7
bosschemical
95-48-7
o-Cresol (chemical formula C7H8O, structure CH3C6H4OH, CAS 95-48-7) is the ortho-isomer of cresol, a colourless to white crystalline solid. It is also known as 2-methylphenol. It is a fine chemical intermediate derived from benzene for industrial and fragrance applications. MCPA herbicides for weed control in farmland, methomyl insecticides for rice planthopper control in rice paddies, photoresist resins for semiconductor chip lithography, tricresyl phosphate plasticisers in flexible PVC, Lysol for disinfection and even the smoky, caramelised notes in coffee and chocolate flavourings, the peaty aroma in whisky and the leather and animal notes in high-end perfumes all
Basic information: Molecular formula C7H8O, molecular weight 108.14, CAS number 95-48-7, EC number 202-423-8; Occurs naturally in coal tar, coffee, tobacco, tea and castoreum. It is produced industrially by alkylation of phenol and methanol with metal oxides as catalysts, or by fractional extraction from coal tar. It is a member of the most important monomers of the phenol-cresol-xylenol series.
It is a colourless to white crystal (melting point 31℃, industrial grade can be a light yellow liquid) with sweet phenolic odour. Density 1.0465g/cm3, boiling point 191℃, slightly soluble in water (about 31g/L at 40℃), easily soluble in ethanol, ether, chloroform, carbon tetrachloride and alkaline solutions. Refractive index 1.5353. Flash point 81℃, autoignition point 598.9℃.
The activity of o-cresol is due to the phenolic hydroxyl and methyl groups, both being etherified (etherification with chloroacetic acid gives MCPA) or esterified (esterification with phosphorus oxychloride gives tricresyl phosphate, esterification with methyl carbamoyl gives methoxycarboxylic acid) or polycondensed with formaldehyde (cresol-formaldehyde resin). The ortho- and para-positions of the benzene ring can be chlorinated, nitrated and alkylated (alkylation of propylene gives carvacrol). It can be carboxylated by Kolbe-Schmitt to form o-cresonic acid. It is weakly acidic, soluble in alkaline solutions and phenolic disinfectant and preservative activity. It must be kept away from oxidisers and sources of ignition and sealed in a moisture-proof container.
From the perspective of mechanism of action, the role of o-cresol is irreplaceable. That is “etherification/esterification/condensation activity of phenolic hydroxyl groups + electrophilic substitution activity of benzene ring + disinfection and antiseptic properties of phenols + contribution of trace aroma”. Mechanism of action in various applications is as follows:
Chlorocresol is produced by chlorination of o-cresol. The phenolic hydroxyl group is converted to an ether by condensation with chloroacetic acid to give MCPA (2-methyl-4-chlorophenoxyacetic acid) which has plant growth hormone activity and controls weeds selectively.
Phenolic hydroxyl groups are esterified with methyl carbamoyl groups to yield carbamate insecticides (e.g., methomyl, which inhibit insect cholinesterase) and esterified with phosphorus oxychloride to yield tricresyl phosphate (TCP), a plasticiser and flame retardant.
o-Cresol and formaldehyde undergo polymerisation to give o-cresol resin (novolac) by condensation under acid catalysis. The benzene ring backbone and phenolic hydroxyl groups give good film forming properties and etching resistance. It is also an important resin component of semiconductor positive photoresists.
The benzene ring has electron-rich ortho and para positions. Carvacrol, the principal component of oregano essential oil, dinitrocresol and o-cresonic acid are obtained by propylene alkylation, nitration and Kolbe-Schmitt carboxylation, respectively; the latter two are used in fragrances and herbicides.
The phenolic hydroxyl groups can penetrate the microbial cell membrane proteins and denature them, thus inhibiting the growth of bacteria and fungi . Cresol soap solution (Lysol) is used for environmental disinfection and is a mixture of o-cresol and m-cresol.
o-Cresol possesses a very low aroma threshold and even a trace amount can give smoky, roasted, spicy and leathery animal notes. It is naturally found in coffee, tobacco and castoreum and as a natural isotropic ingredient it contributes to the "dark base" of fragrances.
To put it simply, o-cresol is a “versatile player in benzene-based fine chemicals”. It is used in the core links of pesticide, electronic materials, plastic additives, disinfection and sanitation and fragrance industries, from herbicides and insecticides to photoresist resins, and from plasticisers to fragrances, through phenolic hydroxyl etherification, esterification, polycondensation, electrophilic substitution of benzene ring and the role of trace aroma.
Application areas: Herbicide and pesticide industry.
Corresponding products: MCPA (2,4-D) herbicide, 2,4-D sodium salt and ester formulations, dinitrocresol (DNOC) herbicide, wheat and rice field herbicides, selective hormone-type herbicides, etc.
Why it works for this purpose:MCPA is prepared by chlorination of o-cresol followed by etherification of the phenolic hydroxyl with chloroacetic acid. It has plant growth hormone activity and can selectively control broadleaf weeds. It is a key intermediate for hormone-type herbicides widely used in wheat and maize fields.
Application areas: Insecticides, plant protection.
Corresponding products: Metelcarb insecticide, methyl carbamate insecticides, pesticides for control of rice planthoppers and leafhoppers, insecticides for fruit trees and vegetables, sanitary insecticides, etc.
Why it works for this purpose: The hydroxyl group of o-cresylphenol is esterified with methyl carbamate to produce carbamate insecticides such as Metelcarb. These insecticides are important intermediates of rice plant protection and act as contact and stomach poison by inhibiting the insect cholinesterase.
Application areas： Electronic materials, resin industry.
Corresponding products: o-cresol novolac resin, semiconductor positive photoresist, epoxy resin curing agent for electronic packaging, copper clad laminate and laminate resin, coating resin, adhesive resin, phenolic moulding compound etc.
Why it works for this application: Condensation polymerisation of o-cresol and formaldehyde to produce o-cresol novolac resin. The benzene ring backbone and phenolic hydroxyl groups impart excellent film forming properties and etching resistance to it, making it a key resin component in semiconductor photoresists and an important matrix resin for electronic packaging and laminates.
Application areas： Additives for plastics and flame retardant materials.
Corresponding products:Tricresyl phosphate (TCP) is used as plasticiser for flexible PVC products, flame retardant plasticiser, hydraulic and lubricating oil additives, flame retardant cable materials, coating flame retardants, nitrocellulose plasticisers, etc.
Why it works for this purpose: o-cresol (and m-cresol) esterifies with phosphorus oxychloride to give tricresyl phosphate, which has both plasticising and flame retardant functions. It can be used to improve the flexibility and flame retardancy of the PVC and is an important type of phosphate ester plasticiser and flame retardant.
Application areas： synthesis of fragrance raw materials, fragrance industry.
Corresponding products: Carvacrol Oregano Essential Oil Thymol Mixture Food Spices & Flavourings Daily Chemicals Fragrance Oral Care Fragrance Antibacterial Fragrance Raw Materials, etc.
Why it works for this purpose: O-cresol is alkylated with propylene to give carvacrol, which has the characteristic spicy aroma and antibacterial activity of oregano. It is an isotropic fragrance raw material for food and daily chemical fragrance formulation.
Application areas：Disinfection and hygienic protection.
Corresponding products:Cresol soap solution (Lysol), cresol disinfectant, instrument and environmental disinfectant, preservatives, phenolic disinfectant preparations, disinfectants for public places etc.
Why it works for this purpose:Cresol soap solution, a mixture of o-cresol and m-cresol, has phenolic disinfectant and antiseptic activity that kills bacteria and fungi. It is a traditional and effective ingredient for disinfection of public places and homes.
Application areas： Analytical chemistry Scientific research labs
Corresponding products: Analytical grade o-cresol, phenolic standard solutions, chromatographic reagents, organic synthesising laboratory reagents, teaching experimental reagents, environmental testing standard substances and so on.
Why it works for this purpose: Reagent-grade o-cresol has high purity and good solubility, which is suitable as an analytical reagent and standard substance, ensuring the accuracy and traceability of organic analysis and testing.
Application areas： Food flavourings, food industry.
Corresponding products: Coffee flavourings Cocoa and chocolate flavourings Nut flavourings (roasted peanuts, roasted hazelnuts, roasted almonds) Caramel flavourings Smoked flavourings (bacon, smoked meat, barbecue flavours) Dairy flavourings Confectionery flavourings etc.
Why it works for this purpose: o-Cresol occurs naturally in coffee, tobacco and castoreum. Even the smallest amounts contribute characteristic, natural caramel, smoky and spicy notes. It synergistically enhances roasting and smoky notes with cocoa, nut and caramel flavourings and meets all FEMA GRAS regulatory requirements.
Application areas：Tobacco products and new tobacco products.
Corresponding products:cigaret flavourings, cigaret flavourings, flavouring capsules, e-cigarette oil flavourings, heated tobacco flavourings, tobacco flavourings, etc.
Why it works for this purpose: o-Cresol is a natural flavouring component in tobacco. Its smoky, spicy and phenolic notes can improve the aftertaste and enhance the natural aroma of tobacco. Blending smoky and roasted aromas is a common phenolic flavouring ingredient in tobacco flavourings
Application areas：Alcoholic drinks industry
Corresponding products: Whisky Flavourings, Rum Flavourings, Brandy Flavourings, Peaty Smoke Flavourings, Aged Oak Barrel Flavourings, Blended Spirits Flavourings, etc.
Why it works for this purpose: Whiskey’s peaty smoke and aged caramel character, among other phenolic notes, are achieved by combining flavouring ingredients such as o-cresol. It can be used for blending spirits as even small quantities can simulate the ageing and smoky characteristics of alcohol beverages.
Application areas: Daily fragrances and personal care products.
Corresponding products: Mens Leather Fragrances, Spicy Colognes, Woody Tobacco Fragrances, Soap Fragrances, Shaving & After Shave Fragrances, Shampoo & Conditioner Fragrances, Home Aromatherapy etc.
Why it works for this purpose: o-Cresol’s leather, spicy and animalic facets offer a deep and rich base to fragrances, enhancing longevity and complexity. It is an important trace fragrance ingredient in leather, tobacco and oriental fragrances.
Application areas： Perfume and flavour blends and luxury perfume raw materials
Corresponding products:Castoreum Fragrance Essence, Animalic Blend Fragrance Essence, Natural Isomeric Fragrance Raw Material, Leather Fragrance Base, Oriental Fragrance Base, Perfume Fixative Base etc.
Why it works for this purpose: o-Cresol is one of the characteristic components of natural castoreum. In its natural isomeric form it can be blended to recreate the leather and animalic notes of castoreum, delivering a warm and sensual deep fragrance profile for high-end perfumes.
Summarize: o-Cresol (2-Methylphenol, CAS 95-48-7) is a versatile building block in the benzene-based fine chemical industry. It has phenolic hydroxyl etherification, esterification, polycondensation, electrophilic substitution of benzene ring, trace aroma contribution and thirteen mature application such as herbicide intermediates, insecticide intermediates, phenolic resins and electronic materials, tricresyl phosphate plasticisers and flame retardants, carvacrol and fragrance intermediates, disinfectants and preservatives, analytical reagents, food flavourings, tobacco flavourings, alcoholic beverage flavourings, daily-use fragrances, and blends of castoreum and animal fragrances. Pesticide intermediates are the largest consumption area, and semiconductor photoresists and high-end perfume fragrances have the highest added value. Agricultural plant protection, chip manufacturing, food flavourings and fragrance products all benefit greatly. Warning: o-Cresol is corrosive and toxic (harmful if swallowed or in contact with skin). The air limit is 5 ppm Flammability: Flammable, flash point 81℃. Concentration used in fragrances is very low (ppm level). Different grades and specifications to be used separately with strict precautions.
