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Chemical Properties
4-Methoxyphenol is a colorless to white,
waxy solid with an odor of caramel and phenol. A combustible solid.
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Uses
Inhibitor for acrylic monomers; stabilizer
for chlorinated hydrocarbons and ethyl
cellulose; UV inhibitor
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Uses
4-Methoxyphenol is an active ingredient and used in dermatology. It is employed as a pharmaceutical drug in skin depigmentation. It is used as polymerization inhibitors. For example, in the radical polymerization of acryaltes and styrene monomers. It is also used as an intermediate in the preparationagrochemicals, liquid crystals. It acts as a stabilizer for the formulation of inks, toners and adhesives. It is mainly used as an additive for textile and leather industries.
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Uses
4-methoxyphenol may be used in the synthesis of butylated hydroxy anisoles via alkylation with methyl tert-butyl ether over a non-zeolitic solid acidic catalyst. This process is eco-friendly when compared to the Friedel-Crafts alkylation reaction. 4-MP may also react with aqueous nitrous acid to form 2-nitro-4-methoxyphenol and benzoquinone in varying ratios depending on the reaction conditions. 4-MP can be used as a building block in designing β-cyclodextrin 4-methoxyphenol conjugates that can be potential ligands for drug complexation.
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Preparation
4-Methoxyphenol was produced according to Oxidation with H2O2 and a Diselenide catalyst.
p-Anisaldehyde (50 mmol) is dissolved in CH2Cl2 (100mL) and (o-NO2PhSe)2 (2 mmol) and 30% H2O2 (13mL, 128 mmol) are added. The mixture is stirred magnetically at room temperature (water bath) for 30 minutes. Insoluble catalyst is removed by filtration and washed with CH2Cl2 (20mL) and water (20mL). It can be reused after drying. To the filtrate and washings, water (100mL) is added, and the layers are separated after shaking. The organic layer is washed subsequently with 10% NaHSO3 (100mL), 10% Na2CO3 (100mL), water (100mL) and dried over Na2SO4. 4-methoxyphenol is obtained by alkaline hydrolysis of the residue. Yield: 93%.
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Indications
Mequinol (4-hydroxyanisole) is a substrate of the enzyme tyrosinase and acts
as a competitive inhibitor of melanogenesis.
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Synthesis Reference(s)
The Journal of Organic Chemistry, 42, p. 1479, 1977 DOI: 10.1021/jo00428a054
Synthesis, p. 751, 1983 DOI: 10.1055/s-1983-30501
Tetrahedron Letters, 34, p. 7667, 1993 DOI: 10.1016/S0040-4039(00)61534-4
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General Description
Pink crystals or white waxy solid.
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Air & Water Reactions
Sensitive to moisture. Water soluble.
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Reactivity Profile
4-Methoxyphenol can react with oxidizing materials.
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Hazard
Eye irritant and skin damage.
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Health Hazard
4-Methoxyphenol is expected to
cause liver and renal toxicity with narcosis, but
only at high levels of exposure.
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Fire Hazard
Combustible
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Safety Profile
Poison by
intraperitoneal route. A skin irritant. When
heated to decomposition it emits acrid
smoke and fumes. See also ETHERS.
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Shipping
UN3335 Aviation regulated solid, n.o.s., Hazard
class: 9; Labels: 9-Miscellaneous hazardous material,
Technical Name Required.
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Purification Methods
Crystallise 4-methoxyphenol from *benzene, pet ether or H2O, and dry it under vacuum over P2O5 at room temperature. Sublime it in vacuo. [Wolfenden et al. J Am Chem Soc 109 463 1987, Beilstein 6 IV 5717.]
