An innovative process of structural modification of kraft lignin (KL) followed by the incorporation of the herbicide picloram (C6H3Cl3N2O2; CAS 1918-02-1) was developed by means the methoxylation reaction in a continuous flow regime. The modified KL-picloram nanoformulation obtained will be used in the study and validation of formulations of controlled release of the herbicide picloram in the subsequent stages in order to prove the environmental gain of this type of formulation against a convention formulation. It is expected that the structural modification will promote an improving of properties as surface area, adsorption and availability of chemical groups for interaction. The modification process, followed by the incorporation of the agrochemical molecule, in addition to being innovative, as it uses flow synthesis, meets the United Nations Sustainable Development Goals.IUPAC.