Cresol from chlorotoluene

This method is capable of producing p- or m-cresol from the corresponding cymene (isopropyltoluene). Alkaline chlorotoluene hydrolysis is used to formulate a cresol mixture with a high m-cresol content. However, information pertaining to domestic use of this process was unavailable (Fiege and Bayer 1987). 

This type of reaction occurs, for example, in the production of m-cresol from o- or p-chlorotoluene. The highly reactive aryne can be attacked in two positions, producing a mixture of isomers. 

Methylphenol. y -Cresol is produced synthetically from toluene. Toluene is chlorinated and the resulting chlorotoluene is hydrolyzed to a mixture of methylphenols. Purification by distillation gives a mixture of 3-methylphenol and 4-methylphenol since they have nearly identical boiling points. Reaction of this mixture with isobutylene under acid catalysis forms 2,6-di-/ f2 -butyl-4-methylphenol and 2,4-di-/ f2 -butyl-5-methylphenol, which can then be separated by fractional distillation and debutylated to give the corresponding 3- and 4-methylphenols. A mixture of 3- and 4-methylphenols is also derived from petroleum cmde and coal tars. 

Table 2. Product distribution obtained in 7-radiolysis of deoxygenated and oxygenated solutions of chlorotoluenes and cresols. Taken from Ref 14 [The numbers are the G values of the individual phenolic products formed in deoxygenated (given in parantheses) and oxygenated solutions of chlorotoluenes (X = Cl) and cresols (X = OH). The total yields are based on G( OH) = 5.6 per 100 eV. n.f = not...

If the separation of the isomers is carried out at the chlorotoluene stage (distilla-tion/crystallization), an o-/m-cresol mixture arises during hydrolysis of o-chloro-toluene in the ratio 1 1, from which pure m-cresol can be produced, whereas the hydrolysis of p-chlorotoluene gives a m-/p-cresol mixture. 

So far, the inverted reaction of phenolate with 3-chlorotoluene is economically not interesting. Catalytic high temperature condensation of phenol and m-cresol produces a statistic mixture [555] from with the desired 3-phenoxyto-luene 274 can be separated (Scheme 199). 

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