13 research outputs found
Adjustment of the Structure of the Simplest Amino Acid Present in Nature—Glycine, toward More Environmentally Friendly Ionic Forms of Phenoxypropionate-Based Herbicides
The use of chemicals for various purposes in agriculture has numerous consequences, such as the contamination of ecosystems. Thus, nowadays it is perceived that their development should adhere to the principles of green chemistry elaborated by Paul Anastas. Consequently, to create more environment-friendly herbicides, we elaborated a ‘green’ synthesis method of a series of ionic liquids (ILs) containing cations derived from glycine. The appropriately modified cations were combined with an anion from the group of phenoxy acids, commonly known as 2,4-DP. The products were obtained with high yields, and subsequently, their properties, such as density, viscosity and solubility, were thoroughly examined to elucidate existing structure–property relationships. All ILs were liquids at room temperature, which enabled the elimination of some serious issues associated with solid active forms, such as the polymorphism or precipitation of an active ingredient from spray solution. Additionally, the synthesized compounds were tested under greenhouse conditions, which allowed an assessment of their effectiveness in regulating the growth of oilseed rape, selected as a model dicotyledonous plant. The product comprising a dodecyl chain exhibited the greatest reduction in the fresh weight of plants, significantly surpassing not only a commercially used reference herbicide but also the potassium salt of 2,4-DP
Comprehensive Ecotoxicity Studies on Quaternary Ammonium Salts Synthesized from Vitamin B<sub>3</sub> Supported by QSAR Calculations
Lately, ionic forms (namely, quaternary ammonium salts, QASs) of nicotinamide, widely known as vitamin B3, are gaining popularity in the sectors developing novel pharmaceuticals and agrochemicals. However, the direct influence of these unique QASs on the development of various terrestrial plants, as well as other organisms, remains unknown. Therefore, three compounds comprising short, medium, and long alkyl chains in N-alkylnicotinamide were selected for phytotoxicity analyses, which were conducted on representative dicotyledonous (white mustard) and monocotyledonous (sorghum) plants. The study allowed the determination of the impact of compounds on the germination capacity as well as on the development of roots and stems of the tested plants. Interestingly, independently of the length of the alkyl chain or plant species, all QASs were established as non-phytotoxic. In addition, QSAR simulations, performed using the EPI Suite™ program pack, allowed the determination of the products’ potential toxicity toward fish, green algae, and daphnids along with the susceptibility to biodegradation. The obtained nicotinamide derivative with the shortest chain (butyl) can be considered practically non-toxic according to GHS criteria, whereas salts with medium (decyl) and longest (hexadecyl) substituent were included in the ‘acute II’ toxicity class. These findings were supported by the results of the toxicity tests performed on the model aquatic plant Lemna minor. It should be stressed that all synthesized salts exhibit not only a lack of potential for bioaccumulation but also lower toxicity than their fully synthetic analogs
Synthesis and efficacy of herbicidal ionic liquids with chlorsulfuron as the anion
In the framework of this research, four new herbicidal ionic liquids (HILs) comprising chlorsulfuron as the anion were synthesized and characterized. The new salts with chlorsulfuron contained the following cations: tetramethylammonium, didecyldimethylammonium, benzyltrimethylammonium and cholinium. All products were obtained with high yields exceeding 90% via acid–base reaction or ion exchange reaction, by the use of environment-friendly solvents. The structures of all synthesized HILs were confirmed by FT-IR, 1H NMR and 13C NMR analyses. Their efficacy against weeds has been studied under field conditions in fiber flax. All HILs showed herbicidal activity but efficiency was highly dependent on the type of cation and weed species. There were no statistically significant differences in the effectiveness of HILs toward common lambsquarters compared to the reference herbicide, except for salt with cholinium cation that showed significantly lower efficiency. As regards barnyard grass control, all HILs exhibited significantly lower efficacy than that of the reference herbicide, except for didecyldimethylammonium salt that showed similar activity. The synthesized products did not cause damage to flax plants. The obtained results confirmed that the herbicidal effectiveness of the active ingredient (chlorsulfuron) in the form of an ionic liquid can be adjusted by the selection of an appropriate cation in the synthesis
Removal of herbicidal ionic liquids by electrochemical advanced oxidation processes combined with biological treatment
International audienceRecently a new group of ionic liquids (ILs) with herbicidal properties has been proposed for use in agriculture. Owing to the design of specific physicochemical properties, this group, referred to as herbicidal ionic liquids (HILs), allows for reducing herbicide field doses. Several ILs comprising phenoxy herbicides as anions and quaternary ammonium cations have been synthesized and tested under greenhouse and field conditions. However, since they are to be introduced into the environment, appropriate treatment technologies should be developed in order to ensure their proper removal and avoid possible contamination. In this study, didecyldimethylammonium (4-chloro-2-methylphenoxy) acetate was selected as a model HIL to evaluate the efficiency of a hybrid treatment method. Electrochemical oxidation or electro-Fenton was considered as a pretreatment step, whereas biodegradation was selected as the secondary treatment method. Both processes were carried out in current mode, at 10 mA with carbon felt as working electrode. The efficiency of degradation, oxidation and mineralization was evaluated after 6 h. Both processes decreased the total organic carbon and chemical oxygen demand (COD) values and increased the biochemical oxygen demand (BOD5) on the COD ratio to a value close to 0.4, showing that the electrolyzed solutions can be considered as 'readily biodegradable.
Pharmacokinetic profile of 1-methylnicotinamide nitrate in rats
Treatment with 1-methylnicotinamide (MNA), a major metabolite of nicotinamide, exerts antithrombotic, anti-inflammatory, and vasoprotective effects. Yet, pharmacokinetic (PK) profile of MNA has not been fully characterized. In the present work, we analyze the PK profile of the MNA given as a nitrate (MNANO3) in comparison to nitrite (MNANO2) or chloride (MNACl) in rats. The bioavailability of MNA administered as MNANO3 equaled 22.4% as compared to MNANO2 or MNACl (9.2% and 9.1%, respectively). Moreover, in single-pass intestinal perfusion experiments, effective permeability of MNA given as MNANO3 was higher as compared to MNA administered as MNANO2 or MNACl. In turn, tmax was the shortest and Cmax the highest (0.22 h and 56.65μM) for intragastrically administered MNANO2 comparing to MNANO3 (1.92 h, 21.74μM) or MNACl (0.63 h, 16.13μM). Transfer constant between central and peripheral compartments (kcp) and volume of distribution (Vss) for MNANO3 (0.33 h-1 and 1.96 L/kg) were higher as compared to MNANO2 or MNACl (0.11 h-1, 0.08 h-1 for kcp and 1.05 L/kg, 0.76 L/kg for Vss, respectively). In conclusion, we characterized PK profile of MNA and demonstrated that nitrate ion augmented bioavailability and favorably modified PK profile of MNA. Furthermore, given vasoprotective properties of MNA as well as nitrate, MNANO3 represents a bifunctional compound
Bioherbicidal Ionic Liquids
This
study presents the properties of a new group of ionic liquids
(ILs) based on various cations and pelargonic acid, a natural nonselective
herbicide. The obtained bio-ILs were obtained with high yield (>92%)
using a metathesis reaction or neutralization of quaternary ammonium
hydroxides and characterized in terms of physicochemical properties.
Tests under greenhouse conditions confirmed the superior herbicidal
activity of ILs compared to pure pelargonic acid, especially against
white mustard (5–10-fold higher efficacy of ILs). Further studies
under field conditions revealed that tetrabutylammonium, benzalkonium,
and oleyltrimethylammonium pelargonates exhibited the highest efficiency
(50.5%, 49.5%, and 46.7%, respectively) at an approximately 3-fold
lower dose of pelargonic acid (2.72 kg per 1 ha) compared to that
used in commercial products (8–11 kg per 1 ha). This allows
classification of the synthesized ILs as bioherbicidal ionic liquids
(bio-HILs). In addition to bio-HILs, two new auxins were also obtained.
Evaluation of antimicrobial activity indicated that the most potent
effect was observed in the case of salts with oleyltrimethylammonium
and tallowtrimethylammonium cations [minimum inhibitory concentration
(MIC), minimum bactericidal concentration (MBC), and minimum fungicidal
concentration (MFC) values lower by 2 orders of magnitude compared
to pelargonic acid]. The fundamental influence of the cation was also
observed during biodegradability assay, as the results varied from
0% to 85% (the highest biodegradability was observed in the case of
dodecylbetainium and tetrabutylammonium pelargonates). The computational
data suggested that biodegradation efficiency seems to be influenced
by the interactions between the cation and the anion. The performed
toxicity tests allowed classification of the obtained bio-HILs as
category V [di(hydrogenated tallow)dimethylammonium pelargonate] or
category IV compounds against rats
Alkyl(C<sub>16</sub>, C<sub>18</sub>, C<sub>22</sub>)trimethylammonium-Based Herbicidal Ionic Liquids
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)
Metsulfuron-Methyl-Based Herbicidal Ionic Liquids
Ten
sulfonylurea-based herbicidal ionic liquids (HILs) were prepared
by combining the metsulfuron-methyl anion with various cation types
including quaternary ammonium ([bis(2-hydroxyethyl)methyloleylammonium]<sup>+</sup>, [2-hydroxyethyltrimethylammonium]<sup>+</sup>), pyridinium
([1-dodecylpyridinium]<sup>+</sup>), piperidinium ([1-methyl-1-propylpiperidinium]<sup>+</sup>), imidazolium ([1-allyl-3-methylimidazolium]<sup>+</sup>,
[1-butyl-3-methylimidazolium]<sup>+</sup>), pyrrolidinium ([1-butyl-1-methylpyrrolidinium]<sup>+</sup>), morpholinium ([4-decyl-4-methylmorpholinium]<sup>+</sup>), and phosphonium ([trihexyltetradecylphosphonium]<sup>+</sup> and
[tetrabutylphosphonium]<sup>+</sup>). Their herbicidal efficacy was
studied in both greenhouse tests and field trials. Preliminary results
for the greenhouse tests showed at least twice the activity for all
HILs when compared to the activity of commercial Galmet 20 SG, with
HILs with phosphonium cations being the most effective. The results
of two-year field studies showed significantly less enhancement of
activity than observed in the greenhouse; nonetheless, it was found
that the herbicidal efficacy was higher than that of the commercial
analog, and efficacy varied depending on the plant species
Glyphosate-Based Herbicidal Ionic Liquids with Increased Efficacy
Eight new glyphosate-based herbicidal
ionic liquids (HILs), containing
both mono- and dianions of glyphosate (benzalkonium glyphosate, bis(2-hydroxyethyl)cocomethylammonium
glyphosate, oleylmethylbis(2-hydroxyethyl)ammonium glyphosate, didecyldimethylammonium
glyphosate, di(hydrogenated tallow)dimethylammonium glyphosate, 4-decyl-4-ethylmorpholinium
glyphosate, di(benzalkonium) glyphosate, and di(bis(2-hydroxyethyl)cocomethylammonium)
glyphosate) were prepared via acid–base reaction between the
corresponding ammonium hydroxides (some premade) and glyphosate free
acid. The transformation of glyphosate free acid into ionic liquids
led to an elimination of melting points in all but one compound and
significant change in solubilities. All HILs exhibited higher thermal
stability than glyphosate free acid. Greenhouse testing indicated
that while at a higher application rate of 360 g/ha the efficacy of
all the HILs was comparable to the commercial herbicide control, at
a lower application rate of 180 g/ha, the efficacy of all HILs was
as much as two and a half to three times higher when compared to the
commercial formulation, and the dianionic glyphosates were the most
effective. In field trials, all but one of the tested HILs demonstrated
excellent efficacy. Laboratory regrowth tests established that the
ionic liquids of glyphosate are efficiently translocated to rhizomes
preventing the regrowth of plants