Occurrence
4-Vinylphenol is found in wine and beer. It is produced by the spoilage yeast Brettanomyces. When it reaches concentrations greater than the sensory threshold, it can give the wine aromas described as barnyard, medicinal, band-aids, and mousy. In wine, 4-vinylphenol can react with other molecules, such as anthocyanidins, to produce new chemical compounds. In white wines vinylphenols are dominant (4-vinylphenol 70-1 150 μg/l, 4-vinylguaiacol 10-490 μg/l) whereas, in red wines, it is the corresponding ethyl phenols.
Reported found in apple, cooked asparagus, dried bonito fish, cloudberries, cooked corn, roasted peanuts, rice bran, sandalwood, wild strawberries, vetiver oil, cooked apple, black currant, red wine, white wine, rose wine, coffee, green tea cognac, tomato, partially fermented tea, microbial fermented tea, black tea, heated soybean, coriander seeds, beer, cognac, peanut butter, soybean, beans, mushrooms, starfruit, tamarind, mango, rice, sweet corn, corn oil, malt, wort, rosemary and Bourbon vanilla.
Production Methods
4-Hydroxystyrene (mp 73.5 C, sublimation range 70–80 ℃ at 0.004 kPa) can be obtained by gas-phase dehydrogenation of 4- ethylphenol at 550–600 ℃ and 0.1 MPa on an iron oxide catalyst and in the presence of steam and an aromatic hydrocarbon as diluents. The alkenylphenol, which polymerizes readily, can be separated from the less acidic unconverted 4-ethylphenol by extracting the condensed reactor effluent with alkali at 30 ℃.
