Dicationic Ionic Liquids of Herbicide 2,4-Dichlorophenoxyacetic Acid with Reduced Negative Effects on Environment

Abstract

Due to high volatility and water solubility, 2,4-dichlorophenoxyacetic acid (2,4-D) can easily enter into the atmosphere and water bodies by volatilization, drift, leaching, or runoff, which results in potential threats to the environment and human health. The physicochemical properties of pesticides can be regulated by preparing their ionic liquids. In this work, a series of dicationic ionic liquids (DILs) of 2,4-D were prepared to reduce its environmental risk and enhance herbicidal activity. The solubility, octanol-water partition coefficient, surface tension, and volatilization rate results of DILs showed that these properties could be optimized by choosing appropriate countercations. Compared to 2,4-D ammonium salt, DILs have lower volatility, water solubility, and surface tension as well as higher lipophilicity. Benefiting from optimized physicochemical properties, DILs HIL8-12 exhibited better herbicidal activity against three typical broadleaf weeds than 2,4-D ammonium salt, and their fresh weight inhibition rates increased by 2.74-46.84%. The safety assessment experiment indicated that DILs were safer to wheat than commercialized forms of 2,4-D. The DILs could reduce the environmental risk of 2,4-D caused by high volatility and water solubility and would be potential alternatives to its commercialized formulations.

Herbicidal Ionic Liquids Containing the Acetylcholine Cation

“…The prepared ILs with acetylcholine cation are new compounds. Ionic liquids with anions: Dicamba, 2,4‐D,,, 2,4‐DP, MCPP, pelargonate (Pel) and iodosulfuron methyl (ISM) are known in the literature.…”

“…Thus its replacement with a bio‐based cation should be beneficial. In the most desired scenario the bio‐based cation should enhance the biodegradation rate of the herbicidal anion . It should also be noted that the test was carried out with the use of activated sludge microorganisms and that the biodegradability of the studied compounds in agricultural soils may differ .…”

“…In the most desired scenario the bio-based cation should enhance the biodegradation rate of the herbicidal anion. [35] It should also be noted that the test was carried out with the use of activated sludge microorganisms and that the biodegradability of the studied compounds in agricultural soils may differ. [24] Furthermore, fully synthetic ILs may notably decrease the biodiversity of microbial populations on the example of phosphonium-based ILs [66] or ammoniumbased ILs, [67] whereas HILs did not significantly impact the overall biodiversity [68] or did not exhibit mutagenic properties.…”

Dicationic triazolium fungicidal ionic liquids with herbicidal properties

“…After purification and drying, the obtained triazolium bromides were used as a substrate in the second step of the synthesis, in the exchange of bromide anions to hydroxides according to the methodology described earlier for herbicidal DILs (Niu et al 2018;Niemczak et al 2015). The obtained methanolic solutions of the precursor in the form of hydroxides were used in the last stage of the method, in the neutralization reaction using two selected herbicidal acids: 2-methyl-4-chlorophenoxyacetic acid (MCPA) and 3,6-dichloro-2-methoxybenzoic acid (Dicamba).…”

“…Dicationic ionic liquids (DILs) comprise two identical or different monocations linked together by a rigid or flexible organic spacer and paired with two singly charged anions (Bhatt et al 2015;Moumene et al 2015;Al-Mohammed et al 2015;Niu et al 2018). Recently, DILs comprising imidazolium, ammonium, pyridinium, and phosphonium cations or their combinations to form asymmetric salts have been developed and extensively studied (Sahu et al 2014;Yonekura and Grinstaff 2014).…”