4-Isopropyl-m-Cresol is a chemical compound, phenol, is a natural monoterpenoid phenol derived from cimene and isomeric with carvacrol, which is found in thyme oil and is an analogue of thymol, more known by the name o-cymen-5-ol, or as 4-Isopropyl-3-Methylphenol, an iso-Isopropyl cresol typically used as a preservative for its antiseptic properties.

The name defines the structure of the molecule:

• 4-Isopropyl refers to the presence of an isopropyl group in the fourth position of the aromatic ring. An isopropyl group is a type of alkyl group consisting of two carbon atoms and seven hydrogen atoms. It is derived from propane and is represented by the formula (CH3)2CH-.
• m-Cresol belongs to cresols, organic compounds and methylated phenols. The "m" stands for meta, indicating the positions of the methyl and hydroxyl groups on the aromatic ring. Cresols are used in the production of some antiseptics, as well as other chemicals.

The synthesis process takes place in several stages:

• Preparation.  m-Cresol can be synthesized by toluene sulphonation, followed by alkaline hydrolysis of the product.
• Alkylation. m-Cresol is alkylated with propene in the presence of a strong acid catalyst such as sulfuric acid or phosphoric acid. This introduces the isopropyl group onto the m-Cresol, forming 4-Isopropyl-m-Cresol.

It appears as a white powder or white crystals, odourless .

What it is used for and where

Dentistry

It is a component placed on the market in 2009-2010. It is used in toothpastes usually accompanied by zinc chloride to maintain gingival health as a biocide, preservative and fragrance ingredient.

Cosmetics

4-Isopropyl-m-Cresol is a restricted ingredient as V / 38  a Relevant Item in the Annexes of the European Cosmetics Regulation 1223/2009.

o-cymen-5-ol is used in shampoos as a preservative, antiseptic, biocide.

Safety

The Cosmetic Ingredients Revue Panel considered the available data to be insufficient to support the safety of this ingredient in cosmetics and believes that studies are needed to demonstrate the absence of chemical leucoderma at use concentrations of p-cresol and mixed cresols, or to demonstrate a dose response from which a safe concentration could be derived (1), while other more recent studies support its safety at low levels (0.1%) in toothpaste (2).

For more information:

o-cymen-5-ol studies

Typical commercial product characteristics 4-Isopropyl-3-Methylphenol

Appearance	White powder
pH	6.5~7.0
Boiling Point	233.8±9.0°C at 760 mmHg
Melting Point	111-114°C
Flash Point	104.1±7.2°C
Density	1.0±0.1 g/cm3
Vapor Pressure	0.0±0.5 mmHg at 25°C
PSA	20.23000
LogP	3.28
Refraction Index	1.523
Water	≤0.2%
Residue on ignition	≤0.1%
UV-vis wavelength	211,270nm
Total impurity	≤1.0%
Each impurity	≤0.5%
Chemical Safety

• Molecular Formula    C₁₀H₁₄O
• Linear Formula    (CH₃)₂CHC₆H₃(CH₃)OH
• Molecular Weight  150.22
• Exact Mass    150.104462
• CAS   3228-02-2
• UNII    H41B6Q1I9L
• EC Number   221-761-7
• DSSTox Substance ID  DTXSID10186026
• IUPAC  3-methyl-4-propan-2-ylphenol
• InChl=1S/C10H14O/c1-7(2)10-5-4-9(11)6-8(10)3/h4-7,11H,1-3H3
• InChl Key      IJALWSVNUBBQRA-UHFFFAOYSA-N
• SMILES   CC1=C(C=CC(=C1)O)C(C)C
• MDL number  MFCD00010704
• PubChem Substance ID    24859017
• ChEBI  34429
• RTECS  GZ717000
• Beistein   1364028
• NACRES NA.22  
• NSC      62111

Synonyms:

• 1-Hydroxy-3-methyl-4-isopropylbenzene
• 1-Hydroxy-3-methyl-4-isopropylbenzene;2-Methyl-4-(1-methylethyl)phenol
• 2-methyl-4-(1-methylethyl)-phenol ;2-Methyl-4-isopropylphenol
• 3-Methyl-4-(1-methylethyl)phenol
• 3-methyl-4-(propan-2-yl)phenol
• 3-Methyl-4-isopropylphenol
• 3-METHYL-4-ISOPROPYLPHENOL
• 3-Methyl-4-isopropylphenol, 99%
• 3-methyl-4-propan-2-ylphenol
• 3-methyl-4-propan-2-yl-phenol
• 4-06-00-03325 (Beilstein Handbook Reference)
• 4-Isopropyl-3-methylphenol
• 4-ISOPROPYL-3-METHYLPHENOL
• 4-isopropyl-3-methyl-phenol
• 4-iso-Propyl-3-methylphenol
• 4-Isopropyl-3-methylphenol, 99%
• 4-Isopropyl-5-methylphenol
• 4-Isopropyl-m-cresol
• 4-ISOPROPYL-M-CRESOL
• Biosal (antibacterial)
• Biosol
• o-CYMEN-5-OL
• o-Cymen-5y-ol
• Phenol, 3-methyl-4-(1-methylethyl)-
• p-Thymol

References___________________________________________________________________

(1) Andersen A. Final report on the safety assessment of sodium p-chloro-m-cresol, p-chloro-m-cresol, chlorothymol, mixed cresols, m-cresol, o-cresol, p-cresol, isopropyl cresols, thymol, o-cymen-5-ol, and carvacrol. Int J Toxicol. 2006;25 Suppl 1:29-127. doi: 10.1080/10915810600716653. 

(2) Kakar A, Newby EE, Ghosh S, Butler A, Bosma ML. A randomised clinical trial to assess maintenance of gingival health by a novel gel to foam dentifrice containing 0.1%w/w o-cymen-5-ol, 0.6%w/w zinc chloride. Int Dent J. 2011 Aug;61 Suppl 3(Suppl 3):21-7. doi: 10.1111/j.1875-595X.2011.00045.x. 

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A randomised clinical trial to assess maintenance of gingival health by a novel dentifrice containing 0.1%w/w o-cymen-5-ol and 0.6%w/w zinc chloride.Protection against enamel demineralisation using toothpastes containing o-cymen-5-ol, zinc chloride and sodium fluoride.
Churchley D, Newby CS, Willson R, Haider A, Schemehorn B, Lynch RJ.
Int Dent J. 2011 Aug;61 Suppl 3:55-9. doi: 10.1111/j.1875-595X.2011.00050.x.

Kakar A, Newby EE, Kakar K, Ghosh S, Targett D, Bosma ML.
Int Dent J. 2011 Aug;61 Suppl 3:13-20. doi: 10.1111/j.1875-595X.2011.00044.x

Antimicrobial effects of o-cymen-5-ol and zinc, alone & in combination in simple solutions and toothpaste formulations.
Pizzey RL, Marquis RE, Bradshaw DJ.
Int Dent J. 2011 Aug;61 Suppl 3:33-40. doi: 10.1111/j.1875-595X.2011.00047.x.

Benefits of a silica-based fluoride toothpaste containing o-cymen-5-ol, zinc chloride and sodium fluoride.
Newby CS, Rowland JL, Lynch RJ, Bradshaw DJ, Whitworth D, Bosma ML.
Int Dent J. 2011 Aug;61 Suppl 3:74-80. doi: 10.1111/j.1875-595X.2011.00053.x.