A macromolecular reaction product mixture formed by bringing together components comprising: a sterically hindered 4-alkoxymethyl-2,6-dihydrocarbylphenol or a sterically hindered 4-hydroxymethyl-2,6-dihydrocarbylphenol, wherein the individual hydrocarbylgroups in the ortho positions each contain 1 to 12 carbon atoms with the total number of carbon atoms in the ortho position being in the range of 4 to 18 carbon atoms; at least one heterocyclic compound which is a monocyclic or dicyclic compound wherein: a) the monocyclic group of the monocyclic compound is fully conjugated and has as the sole heteroatom(s) in the fully conjugated ring thereof (i) one nitrogen atom, one sulfur atom, or one oxygen atom, (ii) one sulfur and one nitrogen atom, one sulfur and one oxygen atom, or one nitrogen and one oxygen atom, or (iii) two nitrogen atoms, two sulfur atoms, or two oxygen atoms, and b) at least one of the cyclic groups of the dicyclic compound is fully conjugated and has as the sole heteroatom(s) in the fully conjugated ring thereof (i) one nitrogen atom, one sulfur atom, or one oxygen atom, (ii) one sulfur and one nitrogen atom, one sulfur and one oxygen atom, or one nitrogen and one oxygen atom, or (iii) two nitrogen atoms, or two sulfur atoms, or two oxygen atoms, optionally the rings of such compounds are substituted by one or more electron releasing groups provided that at least one replaceable activated hydrogen atom remains on the ring; an alkylation catalyst, and optionally, an organic solvent. a sterically hindered 4-alkoxymethyl-2,6-dihydrocarbylphenol or a sterically hindered 4-hydroxymethyl-2,6-dihydrocarbylphenol, wherein the individual hydrocarbylgroups in the ortho positions each contain 1 to 12 carbon atoms with the total number of carbon atoms in the ortho position being in the range of 4 to 18 carbon atoms; at least one heterocyclic compound which is a monocyclic or dicyclic compound wherein: a) the monocyclic group of the monocyclic compound is fully conjugated and has as the sole heteroatom(s) in the fully conjugated ring thereof (i) one nitrogen atom, one sulfur atom, or one oxygen atom, (ii) one sulfur and one nitrogen atom, one sulfur and one oxygen atom, or one nitrogen and one oxygen atom, or (iii) two nitrogen atoms, two sulfur atoms, or two oxygen atoms, and b) at least one of the cyclic groups of the dicyclic compound is fully conjugated and has as the sole heteroatom(s) in the fully conjugated ring thereof (i) one nitrogen atom, one sulfur atom, or one oxygen atom, (ii) one sulfur and one nitrogen atom, one sulfur and one oxygen atom, or one nitrogen and one oxygen atom, or (iii) two nitrogen atoms, or two sulfur atoms, or two oxygen atoms, optionally the rings of such compounds are substituted by one or more electron releasing groups provided that at least one replaceable activated hydrogen atom remains on the ring; a) the monocyclic group of the monocyclic compound is fully conjugated and has as the sole heteroatom(s) in the fully conjugated ring thereof (i) one nitrogen atom, one sulfur atom, or one oxygen atom, (ii) one sulfur and one nitrogen atom, one sulfur and one oxygen atom, or one nitrogen and one oxygen atom, or (iii) two nitrogen atoms, two sulfur atoms, or two oxygen atoms, and b) at least one of the cyclic groups of the dicyclic compound is fully conjugated and has as the sole heteroatom(s) in the fully conjugated ring thereof (i) one nitrogen atom, one sulfur atom, or one oxygen atom, (ii) one sulfur and one nitrogen atom, one sulfur and one oxygen atom, or one nitrogen and one oxygen atom, or (iii) two nitrogen atoms, or two sulfur atoms, or two oxygen atoms, an alkylation catalyst, and optionally, an organic solvent.