Friedel-Crafts reaction 6>-cresol

In reaction (b) (Fig. 2) the radioactive yield was only 8% because, contrary to normal Friedel-Crafts reactions, the radioactive m-[3- " C]cresol could... 

A low purity (40-80%) divinylbenzene and chloromethylstyrene were used in the presence of a Friedel-Crafts catalyst (AICI3) for the synthesis of a polymeric phenolic antioxidant from p-cresol and l,3-bis(l-hydroxy-l-methylethyl)benzene in the presence of p-toluene sulfonic acid [115]. The obtained product was either used directly as AO for thermosetting resins or was treated consecutively with a-methylstyrene [116] or /ert-butylalcohol [117]. Other polymeric phenolic AO were obtained by reaction of phenol with p-men thane-1,8-diol, l-p-menthen-8-ol or limonene [118] or of p-cresol with 3- or 4-chloromethylstyrene in the presence of BF3-etherate or anhydrous AICI3 [119] the product thus obtained was finally aralkylated by a-methylstyrene. Thermostabilizer and/or LS for PUR was obtained, e.g. 98. 

The Friedel-Crafts alkylation of phenol and p-cresol with tert-butanol, isopropanol and n-propanol was investigated [50, 51] (Scheme 14.6). At 275 °C, concentrations of H3O+ and OH reached a maximum, this is therefore the temperature applied for this acid-catalyzed reactions. The fastest alkylation of phenol was the reaction of tert-butanol with phenol. After a short reaction time, up to 17 % 2-tert-butyl-phenol was found. This yield decreases to the equihbrium value of aroimd 10 % (yields relative to initial phenol content). The yield of 4-tert-butylphenol reaches 20 % and the residual phenol content was around 70 % after attaining equilibrium. 

The formation of cresols (and xylenols) by Friedel-Crafts type alkylation in the reaction of phenol with methanol at 300-450°C over a solid catalyst usually a modified metal oxide is an important and well established synthetic route (ref.22) and typically can result in predominantly o/p substitution (o-cresol,54%, p-cresol,30%, and m-cresol, 17%). Selectivity can be achieved with a magnesium oxide or metal oxide-iron oxide mixture to afford o-cresol and... 

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