Methods for the alkylation of the ortho position of phenols having at least one ortho-hydrogen are known in the art. Such methods are usually carried out in the presence of a catalyst.
Hamilton, U.S. Pat. No. 3,446,856 discloses a method for methylating the ortho positions of phenol by the vapor phase reaction of a phenol with methanol in the presence of magnesium oxide at a temperature in the range of 475.degree. to 600.degree. C.
Van Sorge, U.S. Pat. No. 3,873,628, discloses a method for the ortho-alkylation of phenol in the presence of a catalyst consisting of a mixture of magnesium oxide and manganese sulfate.
Other Van Sorge patents describe methods for the ortho-alkylation of phenols using a magnesium oxide catalyst together with a "promoter" consisting of manganese oxide (U.S. Pat. No. 3,974,229), or a magnesium oxide catalyst bonded with an inert organic cellulosic polymeric binder (U.S. Pat. No. 3,972,828).
It is desirable to carry out the ortho-alkylation of phenols in the presence of a catalyst which does not depend on the use of a promoter compound or polymeric binders for the catalyst. The procedure described in the aforementioned Hamilton patent, using magnesium oxide alone serves the purpose to some extent. However, it is known that in Hamilton's procedure the service life of the magnesium oxide catalyst is relatively short because of the high temperatures required, 475.degree. to 600.degree.. , and there is only moderate selectivity with respect to methanol.