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There are a few other important low molecular weight phenols obtained from the fast pyrolysis process
such as syringol, coniferaldehyde and syringaldehyde. However, these compounds currently have
limited industrial application. This is mainly because of the difficulty, and hence cost, associated with
their derivation.
For most of the phenols, actual production figures and import and export data are often poorly
documented. This is because these compounds are generally produced in small quantities throughout
the third world as extractives from natural products. However, the information that is available reveals
that production is small and very fragmented.
11.3.1 Phenol
At present, phenol is synthesised from petroleum products. The process involves reaction of benzene
with propylene to form cumene, which is then oxidised to yield cumene hydroperoxide. Subsequent
cleavage of cumene hydroperoxide yields phenol and acetone. Other phenols may then be derived
from phenol through various substitution reactions. Approximately 20,000 tons/pa of phenol is
manufactured in Australia. All of it is produced by Huntsman Chemicals (plant formerly owned by
Monsanto) at West Footscray in Victoria. Australian imports of phenol are substantial and are
estimated to be around 80 million dollars/annum. The real figure is probably much higher because this
figure does not account for phenol present in resin formulations.
In 2001, world production of phenol was approximately 8 Mt and the corresponding price was about
US$550-700/ton 123 . Thus, the total market value of raw phenol is about 4.4-5.6 billion USD. In 1981,
world production was only 3.3 Mt 124 . It is therefore apparent that in the last 20 years, the demand for
phenol has increased enormously and it is expected that this trend will continue into the foreseeable
future with an average of 3-4 new manufacturing plants being commissioned annually 123 .
Current Application of Phenol
Phenols are used in a wide variety of applications, some of which are briefly discussed.
Resins
A very important application of phenol is in resins/adhesives. Such resins are utilised widely in the
wood panels industry where they impart high strength and dimensional stability to the panel products.
Phenolic resins generally incorporate formaldehyde as a cross-linking agent.
Chemical precursor
Phenol is the precursor for the synthesis of many aromatic compounds such as adipic acid, salicylic
acid, phenolphthalein, pentachlorophenol, acetophenetidin, picric acid, germicidal paints,
pharmaceuticals, laboratory reagent, dyes and indicators. Many of the compounds derived from phenol
have important industrial applications ranging from resins (such as resorcinol) to explosives (such as
2,4,6-trinitrophenol (picric acid)) to pharmaceuticals (such as aspirin).
Slimicide
Phenol is an effective slimicide. Slimicides prevent slimy growths such as those which can occur on
wood pulps.
Biocide/disinfectant
Phenol is quite toxic to a range of organisms and it has therefore been classified as a biocide. It is also
used as a general disinfectant.
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