Sustainable Design of New Ionic Forms of Vitamin B(3) and Their Utilization as Plant Protection Agents

[Image: see text] This study demonstrates the utilization of naturally occurring nicotinamide (vitamin B(3)) in the sustainable synthesis of organic salts with application potential as environmentally friendly agrochemicals. The designed ionic pairs, obtained with high yields, consisted of N-alkylnicotinamide cation and commercially available herbicidal anions: 2,4-dichlorophenoxyacetate (2,4-D) and 4-chloro-2-methylphenoxyacetate (MCPA). The study confirmed the strong influence of the length of alkyl chain in products on the physicochemical properties as well as the development of cornflower and oil-seed rape. The majority of tested salts showed significantly better herbicidal activity (by approx. 30–50%) compared to the reference herbicide. Furthermore, N-hexadecylnicotinamide 4-chloro-2-methylphenoxyacetate was significantly more effective than the commercial formulation in the dose–response test. Their negligible vaporization, multiple times lower than that of commonly used dimethylammonium salts, eliminates one of the greatest threats of currently applied plant protection agents. Additionally, the risk of product migration or bioaccumulation in the environment was assessed as extremely low.