Nitration of model compounds of lignosulfonic acids

1. β-Alkyl-aryl ether linkages and veratryl and p-hydroxyphenyl structural fragments that contain a sulfo group attached to theα-C atom of the side chain are stable under the conditions of nitrating lignosulfonic acids. 2. Guaiacyl structures with a sulfo group in the γ-position of the side chain are stable when the nitration is run in organic solvents, while when nitration is in aqueous medium they undergo demethylation with the formation of o-quinone structures. Replacement of the side chain by the nitro group fails to occur.