title: Alkyl(C16, C18, C22)trimethylammonium-Based Herbicidal Ionic Liquids.
abstract: In the framework of this study a synthesis methodology and characterization of long alkyl herbicidal ionic liquids (HILs) based on four commonly used herbicides (2,4-D, MCPA, MCPP, and dicamba) are presented. New HILs were obtained with high efficiency (>95%) using an acid-base reaction between herbicidal acids and hexadecyltrimethylammonium, octadecyltrimethylammonium, and behenyltrimethylammonium hydroxides in alcoholic medium. Among all synthesized salts, only three compounds comprising the MCPP anion were liquids at room temperature. Subsequently, the influence of both the alkyl chain length and the anion structure on their physicochemical properties (thermal decomposition profiles, solubility in 10 representative solvents, surface activity, density, viscosity, and refractive index) was determined. All HILs exhibited high thermal stability as well as surface activity; however, their solubility notably depended on both the length of the carbon chain and the structure of the anion. The herbicidal efficacy of the obtained salts was tested in greenhouse and field experiments. Greenhouse testing performed on common lambsquarters (Chenopodium album L.) and flixweed (Descurainia sophia L.) as test plants indicated that HILs were characterized by similar or higher efficacy compared to commercial herbicides. The results of field trials confirmed the high activity of HILs, particularly those containing phenoxyacids as anions (MCPA, 2,4-D, and MCPP).
authors.affiliation: Department of Chemical Technology, Poznan University of Technology , Poznan 60-965, Poland.
authors.forename: Juliusz
authors.initials: J
authors.lastname: Pernak
authors.affiliation: Department of Chemical Technology, Poznan University of Technology , Poznan 60-965, Poland.
authors.forename: Rafał
authors.initials: R
authors.lastname: Giszter
authors.affiliation: Department of Chemical Technology, Poznan University of Technology , Poznan 60-965, Poland.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Biedziak
authors.affiliation: Department of Chemical Technology, Poznan University of Technology , Poznan 60-965, Poland.
authors.forename: Michał
authors.identifier: http://orcid.org/0000-0002-4364-8267
authors.initials: M
authors.lastname: Niemczak
authors.affiliation: ADOB Sp. z o.o. Sp.k. , Poznan 61-070, Poland.
authors.forename: Radosław
authors.initials: R
authors.lastname: Olszewski
authors.affiliation: Institute of Plant Protection - National Research Institute , Poznan 60-318, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Marcinkowska
authors.affiliation: Institute of Plant Protection - National Research Institute , Poznan 60-318, Poland.
authors.forename: Tadeusz
authors.initials: T
authors.lastname: Praczyk
mesh_terms: D015084:2,4-Dichlorophenoxyacetic Acid / Q000737:chemistry; D008456:2-Methyl-4-chlorophenoxyacetic Acid / Q000737:chemistry; D008725:Bis-Trimethylammonium Compounds / Q000737:chemistry; D019607:Brassicaceae / Q000187:drug effects; D060326:Chemistry Techniques, Synthetic; D027463:Chenopodium album / Q000187:drug effects; D003996:Dicamba / Q000737:chemistry; D006540:Herbicides / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D052578:Ionic Liquids / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D057685:Plant Weeds / Q000187:drug effects; D011044:Poland; D012995:Solubility; D013329:Structure-Activity Relationship; D013499:Surface Properties; D014783:Viscosity
chemical_list: D008725:Bis-Trimethylammonium Compounds; D006540:Herbicides; D052578:Ionic Liquids; D015084:2,4-Dichlorophenoxyacetic Acid; D008456:2-Methyl-4-chlorophenoxyacetic Acid; D003996:Dicamba
keywords: efficacy; growth regulators; herbicidal ionic liquids; long alkyl; phenoxyacids