A method for the dealkylation and/or deacylation of a compound of formula wherein: each occurrence of R 1 is independently selected to be -OH, or -O-alkyl; wherein alkyl refers to a linear, branched or cyclic hydrocarbon group which may be saturated or contain one or more unsaturated bonds; each occurrence of R 2 is independently selected from an alkyl group which may be linear, branched or cyclic; which may be saturated or containing one or more unsaturated bonds, or which may be an aromatic group; wherein said R 2 may optionally further contain one or more heteroatoms and/or one or more substituents; n is 1-5; m is 1-5; and the sum of n and m is maximally 6 said method comprising the steps of: a) providing said compound of formula b) if in said compound of formula, said R 2 contains at least one alkyl group which does not have at least one functional moiety; then: b1) alkylating any free -OH groups in said compound of step a); and b2) oxidizing in said compound of step b1); said alkyl groups which do not have said at least one functional moiety; wherein said at least one functional moiety is selected from the list consisting of: -OH, =O, a double bond or an amine; c) preparing a reaction mixture by contacting said compound of step a), or where applicable step b), with an aqueous reaction mixture containing an acid having a pKa of maximum 3.0 or a Lewis acid, under an inert gas atmosphere; wherein step c) is carried out at a temperature of at least 200 °C and a pressure of at least 20 bar; d) obtaining from step c) a phenolic compound of formula (Ia) wherein p is equal to n. each occurrence of R 1 is independently selected to be -OH, or -O-alkyl; wherein alkyl refers to a linear, branched or cyclic hydrocarbon group which may be saturated or contain one or more unsaturated bonds; each occurrence of R 2 is independently selected from an alkyl group which may be linear, branched or cyclic; which may be saturated or containing one or more unsaturated bonds, or which may be an aromatic group; wherein said R 2 may optionally further contain one or more heteroatoms and/or one or more substituents; n is 1-5; m is 1-5; and the sum of n and m is maximally 6 said method comprising the steps of: a) providing said compound of formula b) if in said compound of formula, said R 2 contains at least one alkyl group which does not have at least one functional moiety; then: b1) alkylating any free -OH groups in said compound of step a); and b2) oxidizing in said compound of step b1); said alkyl groups which do not have said at least one functional moiety; wherein said at least one functional moiety is selected from the list consisting of: -OH, =O, a double bond or an amine; c) preparing a reaction mixture by contacting said compound of step a), or where applicable step b), with an aqueous reaction mixture containing an acid having a pKa of maximum 3.0 or a Lewis acid, under an inert gas atmosphere; wherein step c) is carried out at a temperature of at least 200 °C and a pressure of at least 20 bar; d) obtaining from step c) a phenolic compound of formula (Ia) a) providing said compound of formula b) if in said compound of formula, said R 2 contains at least one alkyl group which does not have at least one functional moiety; then: b1) alkylating any free -OH groups in said compound of step a); and b2) oxidizing in said compound of step b1); said alkyl groups which do not have said at least one functional moiety; wherein said at least one functional moiety is selected from the list consisting of: -OH, =O, a double bond or an amine; b1) alkylating any free -OH groups in said compound of step a); and b2) oxidizing in said compound of step b1); said alkyl groups which do not have said at least one functional moiety; c) preparing a reaction mixture by contacting said compound of step a), or where applicable step b), with an aqueous reaction mixture containing an acid having a pKa of maximum 3.0 or a Lewis acid, under an inert gas atmosphere; wherein step c) is carried out at a temperature of at least 200 °C and a pressure of at least 20 bar; d) obtaining from step c) a phenolic compound of formula (Ia) wherein p is equal to n.