Cations impact the biodegradation of iodosulfuron-methyl herbicidal ionic liquids by fungi

In the framework of this study, six fungal isolates which demonstrated a high capability for biodegrading iodosulphuron-methyl sodium as well as herbicidal ionic liquids based on this herbicide were isolated from different soil samples. The isolates were identified based on the ITS region, whereas biodegradation residues were determined based on LC-MS/MS. Depending on the isolate, the half-lives values of the biodegraded herbicide or herbicidal ionic liquid ranged significantly from just 1.25 days to more than 40 days. The research findings unveiled that the structure of cations is a central limiting factor affecting fungal growth and herbicide transformation in case of ionic liquids. The length of the alkyl chain has been identified as the primary driver of herbicide toxicity, emphasizing the importance of structural factors in herbicide design. In cases when dodecyl(2-hydroxyethyl)dimethyl cation was used, its biodegradation ranged from 0 to approx. 20% and the biodegradability of the iodosulfuron-methyl was notably limited for the majority of the studied isolates. This knowledge provides guidance for development and selection of herbicides with reduced environmental impact. This study highlights the ecological importance of soil fungi, their potential role in herbicide biodegradation, the influence of cations on fungal growth and herbicide transformation, and the structural factors governing herbicide toxicity. Further research in these areas may lead to more efficient and environmentally friendly approaches to herbicide management.

Ecotoxicity studies reveal that organic cations in dicamba-derived ionic liquids can pose a greater environmental risk than the herbicide itself

The following research provides novel and relevant insights into potential environmental consequences of combination of various organic cations with commercial systemic herbicide (dicamba), in accordance with a 'herbicidal ionic liquids' (HILs) strategy. Toxicity assays of five dicamba-based HILs comprising different hydrophobic and hydrophilic cations, namely choline [CHOL][DIC], ethyl betainate [BETC2][DIC], decyl betainate [BETC10][DIC], hexadecyl betainate [BETC16][DIC] and didecyldimethylammonium [DDA][DIC]), have been tested towards bacteria (Pseudomonas putida, Escherichia coli, Bacillus subtilis), algae (Chlorella vulgaris), fresh and marine water crustaceans (Daphnia magna, Artemia franciscana). The structure of respective substituents in the cation emerged as a decisive determinant of toxicity in the case of tested species. In consequence, small ions of natural origin ([CHOL] and [BETC2]) demonstrated toxicity numerous orders of magnitude lower compared to fully synthetic [DDA]. These results emphasize the role of cations' hydrophobicity, as well as origin, in the observed acute toxic effect. Time-dependent toxicity assays also indicated that betaine-type cations comprising an ester bond can rapidly transform into less harmful substances, which can generally result in a reduction in toxicity by even several orders of magnitude. Nonetheless, these findings challenge the concept of ionic liquids with herbicidal activity and give apparent parallels to adjuvant-dependent toxicity issues recently noted in typical herbicidal formulations.

2,4-D versus 2,4-D based ionic liquids: Effect of cation on herbicide biodegradation, tfdA genes abundance and microbiome changes during soil bioaugmentation

The commercial formulations of herbicides rely on surfactants which increase the efficiency of active substance. Herbicidal ionic liquids (ILs), in which cationic surfactants are combined with herbicidal anions, allow for additives' reduction and ensure very good herbicide performance with lower doses. We aimed to test the impact of synthetic and natural cations on biological degradation of 2,4-dichlorophenoxyacetic acid (2,4-D). Although primary biodegradation was high, the mineralization in agricultural soil indicated incomplete conversion of ILs to CO₂. Even the introduction of naturally-derived cations resulted in an increase in the herbicide's half-lives - from 32 days for [Na][2,4-D] to 120 days for [Chol][2,4-D] and 300 days for the synthetic tetramethylammonium derivative [TMA][2,4-D]. Bioaugmentation with 2,4-D-degrading strains improves the herbicides' degradation, which was reflected by higher abundance of tfdA genes. Microbial community analysis confirmed that hydrophobic cationic surfactants, even those based on natural compounds, played a negative role on microbial biodiversity. Our study provides a valuable indication for further research related to the production of a new generation of environmentally friendly compounds. Moreover, the results shed a new light on the ionic liquids as independent mixtures of ions in the environment, as opposed to treating them as new type of environmental pollutants.

Glyphosate versus glyphosate based ionic liquids: Effect of cation on glyphosate biodegradation, soxA and phnJ genes abundance and microbial populations changes during soil bioaugmentation

The applicability of herbicidal ionic liquids (HILs) as an alternative form of herbicides is currently evaluated. Yet, the available research is lacking information on the behaviour of herbicidal ionic liquids upon addition to the environment, i.e., if cations and anions act as separate moieties or remain an ionic salt. Hence, we tested degradation of five HILs with the glyphosate anion, their bioavailability in soil, toxicity towards microorganisms, impact on the biodiversity and the abundance of phnJ and soxA genes. The cations were proven to be slightly or moderately toxic. The properties of cations determined the properties of the whole formulation, which might suggest that cations and anion act as the independent mixture of ions. The mineralisation efficiencies were in the range of 15-53%; however, in the case of cations (except non-toxic choline), only 13-20% were bioavailable for degradation. The hydrophobic cations were proven to be highly sorbed, while the anion was readily available for microbial degradation regardless of its counterion. The approach to enrich test samples with isolated microorganisms specialised in glyphosate degradation resulted in higher degradation efficiencies, yet not high enough to mitigate the negative impact of cations. In addition, increased activity of enzymes participating in glyphosate degradation was observed. In the view of obtained results, the use of cationic surfactants in HILs structure is not recommended, as sorption was shown to be determining factor in HILs degradation efficiency. Moreover, obtained results indicate that corresponding ions in HILs might act as separate moieties in the environment.

Rhodobacter sphaeroides as a model to study the ecotoxicity of 1-alkyl-3-methylimidazolium bromide

The purple non-sulfur bacterium Rhodobacter sphaeroides was selected as a biological model to investigate its response to the toxicity of 1-alkyl-3-methylimidazolium bromide ([C_nmim]Br), a type of ionic liquid (IL), with different alkyl chain lengths (n describes the number of carbon atoms in the alkyl chain). The inhibition of bacterial growth by [C_nmim]Br was positively correlated with n. Morphological characterization revealed that [C_nmim]Br caused cell membrane perforation. The signal amplitude of the electrochromic absorption band shift of endogenous carotenoids showed a negatively linear correlation with n, and the amplitude of the blue-shift of the B850 band in light-harvesting complex 2 showed a positively linear correlation with n. Furthermore, an increase in blocked ATP synthesis and increase in antioxidant enzyme activity were observed in chromatophores treated with ILs containing longer alkyl chains. In summary, the purple bacterium can be developed as a model to monitor ecotoxicity and examine the mechanism of IL toxicity.

Inventory of biodegradation data of ionic liquids

Ionic liquids (ILs) are increasingly of interest for environmentally open applications. Therefore, completely mineralising ILs are highly desirable. We reviewed the current state of knowledge on ILs' environmental biodegradability and identified research needs. Literature data were evaluated as for applied standard methods (e.g. OECD, ISO, APHA) for biodegradation of ILs in order to get an overview on the validity of the test results received and ILs' biodegradability. 109 studies were evaluated. The ILs were categorised based on the cation's core structure. The biodegradation data was classified according to a traffic light system (red: 0-19% degradation, amber: 20-59% degradation, green: ≥ 60% degradation). Not all studies could be assessed for compliance with the test guidelines due to missing test parameters. Moreover, no study discussed all validation criteria as defined by the test guidelines. Consequently, the reliability and quality of the existing biodegradation data is restrained. With regard to the different cations classified for ≥ 60% biodegradability, phosphonium ILs are the least biodegradable, followed by imidazolium ones. The most ILs that were biodegradable are cholinium ILs. The results indicate the need for more and qualitatively better testing according to standard methods including application and reporting of all validation criteria in order to get reliable data that enables the comparison of the test data and a comprehensive understanding of ILs' biodegradability. Moreover, reliable data allows the selection of sufficiently environmentally biodegradable ILs if an introduction into the environment during use cannot be excluded.

Novel esterquat-based herbicidal ionic liquids incorporating MCPA and MCPP for simultaneous stimulation of maize growth and fighting cornflower

Modern agricultural practices are often based on the use of mixtures of specific herbicides to achieve efficient crop protection. The major drawbacks of commercial herbicidal formulations include the necessity to incorporate toxic surfactants and high volatility of active substances. Transformation of herbicides into herbicidal ionic liquids (HILs) seems to be a promising alternative which allows to almost completely reduce volatility due to ionic interactions. In the scope of this research, we transformed (2-methyl-4-chlorophenoxy)acetic acid (MCPA) into a quaternary ester (esterquat) with the use of derivatives of 2-dimethylaminoethanol. The obtained esterquats were later coupled with (±)-2-(4-chloro-2-methylphenoxy)propionic acid (MCPP) in the form of an anion. The combination of MCPA and MCPA is commonly applied in the UK, EU countries and also in the USA to increase the spectrum of targeted weed species. In the framework of this study, novel HILs with an esterquat moiety incorporating a long alkyl chain (C₈, C₉, C₁₀, C₁₁, C₁₂, C₁₄) were prepared and characterized in terms of basic physicochemical properties (solubility and volatility) as well as biodegradability. Their phytotoxicity was assessed towards cornflower (Centaurea cyanus) as a model weed and maize (Zea mays) as a crop plant. The presence of the esterquat cation contributed to satisfactory solubility in water and other low polar solvents, which eliminates the need to add exogenous adjuvants. Further experiments indicated that the tested HILs stimulated the germination stage of maize and maintained high herbicidal activity towards cornflower. No significant differences in terms of properties were observed in case of HILs which included alkyl substituents with an odd number of carbon atoms. Future studies should be focused on structural modifications in order to improve the biodegradability as well as field studies for evaluation of commercial applications.

Herbicidal Ionic Liquids: A Promising Future for Old Herbicides? Review on Synthesis, Toxicity, Biodegradation, and Efficacy Studies

The transformation of agrochemicals into herbicidal ionic liquids (HILs) has been suggested as a solution to problems associated with commercial forms of herbicides. The aim of this review was to summarize the latest progress in the field of HILs, including their synthesis as well as physicochemical and biological properties, and to address the areas that require further research in order to ensure their safe commercialization (e.g., data regarding biodegradability, toxicity, and environmental fate). The first part of the review provides an in-depth summary of the current state of knowledge regarding HILs, particularly the anions and cations used for their synthesis. The second part highlights the employed synthesis methods and elucidates their respective advantages and limitations. The third section is focused on the characterization of HILs with emphasis on the methods and factors that are significant in terms of their practical application. Subsequently, the issues associated with the biodegradation and toxic effects of HILs are discussed based on the relevant literature reports. All sections include comprehensively tabulated data in order to enable rapid comparison of utilized approaches. Finally, all the findings are critically analyzed in terms of crucial disadvantages (especially the lack of standardization), which allowed us to establish future recommendations and basic guidelines that are presented in the last section.

Dicamba-Based Herbicides: Herbicidal Ionic Liquids versus Commercial Forms

Dicamba is a widely applied herbicide for crop protection and has potential for volatility. New formulations containing dicamba with greatly reduced volatility, introduced to the market in 2017, still caused foliar injury to crops and other plants in Arkansas and neighboring states in the United States. In response, we proposed the transformation of dicamba into protic as well as aprotic dicamba-based organic salts called herbicidal ionic liquids (HILs). All of the HILs were characterized by high stability, whereas the biological activity of the most effective products, evaluated during greenhouse studies, was found to be greater than that of currently used commercial analogues. Furthermore, the possibility of introducing an alkyl chain of a specific length allows one to obtain plant protection products with the desired physicochemical properties while maintaining herbicidal effectiveness. These studies are expected to aid in the design and development of new herbicidal formulations, which, depending on the weed species, could increase the efficacy of the applied active ingredient. Simultaneously, the volatility of the synthesized compounds, particularly those containing quaternary ammonium cations, was multiple times lower than that of the free acid of dicamba. This strategy minimizes the risk of off-site movement via volatilization, which may cause significant damage to neighboring broadleaf crops and pose a threat to existing ecosystems.

Herbicidal Ionic Liquids Containing the Acetylcholine Cation

This study presents a new group of herbicidal ionic liquids (HILs) based on a cation occurs commonly in nature-acetylcholine. The HILs were obtained with a high yield through ion exchange between acetylcholine chloride and potassium or sodium salts of selected acids with herbicidal activity. The results of the herbicidal activity measurement against common oilseed rape (Brassica napus L.) exceeded those of the commercial products. Spray solutions of the synthesized HILs revealed high surface activity and wetting properties which further manifested as higher herbicidal activity. The reduction of surface tension and low contact angles together with the specific action of acetylcholine allowed for better penetration of synthesized HILs into plant tissues. In addition, OECD 301F tests confirmed high mineralization of the HILs. The simple transformation of commercial herbicides into acetylcholine HILs proved to be a very effective method of increasing their activity, and constitutes an interesting solution to the problem of weed infestation with the use of a substance commonly found in nature.

Hybrid electrochemical and biological treatment of herbicidal ionic liquids comprising the MCPA anion

The present study was focused on the application of an electrochemical oxidation process combined with biodegradation for the removal of novel Herbicidal Ionic Liquids (HILs) -promising protection plant products which incorporate herbicidal anions and ammonium cations. The influence of carbon chain length (n = 8, 10, 12, 14, 16, 18) in the dialkyldimethylammonium cations on electrochemical oxidation kinetics, degradation efficiency and biodegradation by activated sludge was investigated. It was established that the applied cation influenced the heterogeneous rate constant and diffusion coefficient of electrochemical oxidation. The oxidation efficiency ranged from 17% in case of HILs with C8 alkyl chain to approx. 60% in case of HILs comprising C14 and C16 alkyl chains after 3 h of electrochemical treatment. Subsequent biodegradation studies revealed that electrochemical oxidation improved the mineralization efficiency of the studied HILs. The mineralization efficiency of electrochemically-treated HILs ranged from 28% in case of HILs comprising the C8 alkyl chain to 57% in case of HILs with C14 and C16 alkyl chains after 28 days. In case of untreated HILs, the corresponding mineralization efficiency ranged from 0 to 8%, respectively. This confirms the feasibility of a hybrid electrochemical-biological approach for treatment of herbicidal ionic liquids based on MCPA.

Difunctional ammonium ionic liquids with bicyclic cations

The increasing limitations regarding the applied amounts of plant protection make hybrid ionic liquids an interesting class of compounds belonging to the III generation ILs.

Adaptation of bacteria Escherichia coli in presence of quaternary ammonium ionic liquids

This paper presents the adaptation of Escherichia coli Gram-negative bacteria to increased concentrations of ionic liquids. Theophylline-based quaternary ammonium salts were used as an example of an ionic liquid that on the one hand includes an anion of natural origin and on the other hand is characterized by amphiphilic properties due to aliphatic chains in its structure. Theophylline-based ionic liquids can be synthesized relatively cheaply and easily and can exhibit strong antibacterial properties depending on the alkyl chain length. These compounds can also strongly affect bacterial membrane properties, including changes in electrokinetic potential as well as net surface charge. The experiments performed in this study succeeded in obtaining bacterial cultures growing at a tetradecyltrimethylammonium theophyllinate concentration three times higher than the minimum inhibition and bactericidal concentration. The adapted bacteria were characterized by intriguing changes in morphology and grew in the form of almost one-millimeter spheres in a liquid medium. It was shown that cultivation of adapted bacteria with tetradecyltrimethylammonium theophyllinate resulted in changes in the lipid membrane composition and protein patterns of the bacterial lysates, depending on the ionic liquid concentration. This study also revealed that such bacterial adaptation can increase sensitivity to antibiotics by affecting membrane properties like ionophores. These results can be potentially important with regard to synergistic or antagonistic action with other bactericidal compounds like antibiotics and nanoparticles.

Ammonium 2,2'-thiodiacetates - Selective and environmentally safe herbicides

2,2'-Thiodiacetic acid derivatives have a wide application potential, mainly in coordination chemistry. This research indicates that quaternary ammonium 2,2'-thiodiacetate salts may also be potent herbicidal agents used in agriculture. To provide a rationale for this statement, the toxic effect by a alkyl and aryl quaternary ammonium salts (QASs) on plant growth was investigated. The phytotoxicity of these compounds was tested against cultivated monocotyledonous (spring barley) and dicotyledonous (common radish) plants, whereas herbicidal activity was investigated in relation to popular weeds species (white goosefoot, sorrel and gallant-soldier). The results showed that aliphatic QASs possessed a low phytotoxicity to food crops and that some of them (in particular triethylammonium salt) had potent and selective herbicidal properties against common weeds, such as sorrel and gallant-soldier. However, the investigated compounds appeared to be ineffective herbicides against white goosefoot.

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

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.

Dissipation Dynamic and Final Residues of Oxadiargyl in Paddy Fields Using High-Performance Liquid Chromatography-Tandem Mass Spectrometry Coupled with Modified QuEChERS Method

Oxadiargyl, which binds to the protoporphyrinogen oxidase IX to exhibit herbicide activity, is mainly used in the prevention of certain perennial broadleaved and grass weeds during the preemergence of rice in paddy fields. However, oxadiargyl affects the germination and seedling growth of rice, causing damage to the plant and reducing rice yield. Hence, monitoring fate and behaviour of oxadiargyl in rice paddy fields is of great significance. A modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) sample preparation method coupled with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was established in paddy water, paddy soil, rice straw, paddy hull, and brown rice. We validated this method for the first time in the analysis of the dissipation dynamic and residues of oxadiargyl over two years (2015⁻2016) at three sites in China. The average recoveries of oxadiargyl ranged from 76.0 to 98.8%, with relative standard deviations of 3.5⁻14.0%. The dissipation curves for paddy soil fit to a first-order kinetic equation, revealing that oxadiargyl degraded rapidly in paddy soil with half-lives (t_1/2) of 4.5⁻7.6 days. The final oxadiargyl residues in all samples remained below the detection limit and the maximum residue limit in China (0.02 mg kg^-1) and Japan (0.05 mg kg^-1) during the harvesting dates and were not detected in rice straw.

Synthesis and Structure-Property Relationships in Herbicidal Ionic Liquids and their Double Salts

In this study, two homologous series of novel herbicidal ionic liquids (HILs) were synthesized in a simple metathesis reaction between alkyl[2-(2-hydroxyethoxy)ethyl]dimethylammonium bromides and alkali metal salts of 4-chloro-2-methylphenoxyacetic acid (MCPA) or 3,6-dichloro-2-methoxybenzoic acid (dicamba), known as popular herbicides from the class of growth regulators. These HILs were subsequently mixed to prepare double-salt herbicidal ionic liquids (DSHILs). The DSHILs were characterized by substantially altered parameters of viscosity, refractive index, glass transition temperatures and surface activity compared to the average values expected for ideal mixtures of their individual components (HILs). Interestingly, DSHILs possessed superior physicochemical properties such as relatively low viscosity or facilitated formation of micelles, which emphasizes the complex nature of multi-ion interactions in the microstructures of ionic liquid mixtures. The biological tests showed improved efficiency of DSHILs against tested weeds compared to the reference herbicides and parent HILs.

Developing ionic liquid forms of picloram with reduced negative effects on the aquatic environment

As a widely used herbicide, picloram has been frequently detected in the aquatic environment due to its high leaching potential and low adsorption by soil. To reduce aquatic environmental risk of this herbicide caused by leaching and runoff, five herbicidal ionic liquids (HILs) based on picloram were prepared by pairing isopropylamine, octylamine, octadecylamine, 1-methylimidazole, 4-methylmorpholine respectively. Their physicochemical properties including water solubility, octanol-water partition coefficient, surface activity, leaching, as well as soil adsorption were compared. The results showed that these properties could be adjusted by appropriate selection of counter cations. The HILs with long alkyl chains in cations had low water solubility and leaching characteristics, good surface tension and lipophilicity, as well as high soil adsorption. Compared with currently used picloram in the forms of potassium salts, HIL3 had more excellent herbicidal activity against broadleaf weeds and may offer a lower use dosage. The HILs based on picloram can reduce its negative effects on the aquatic environment and can be used as a desirable alternative to commercial herbicidal formulations of picloram in future.

Esterquat herbicidal ionic liquids (HILs) with two different herbicides: evaluation of activity and phytotoxicity

Novel weed control agents in the form of herbicidal ionic liquids comprising two different herbicides as a cation and an anion.

Synthesis and properties of ionic liquids based on mecoprop

Ionic liquids as novel herbicidal forms of mecoprop.

Removal of herbicidal ionic liquids by electrochemical advanced oxidation processes combined with biological treatment

Recently 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.'

Biological Activity of Ionic Liquids and Their Application in Pharmaceutics and Medicine

Ionic liquids are remarkable chemical compounds, which find applications in many areas of modern science. Because of their highly tunable nature and exceptional properties, ionic liquids have become essential players in the fields of synthesis and catalysis, extraction, electrochemistry, analytics, biotechnology, etc. Apart from physical and chemical features of ionic liquids, their high biological activity has been attracting significant attention from biochemists, ecologists, and medical scientists. This Review is dedicated to biological activities of ionic liquids, with a special emphasis on their potential employment in pharmaceutics and medicine. The accumulated data on the biological activity of ionic liquids, including their antimicrobial and cytotoxic properties, are discussed in view of possible applications in drug synthesis and drug delivery systems. Dedicated attention is given to a novel active pharmaceutical ingredient-ionic liquid (API-IL) concept, which suggests using traditional drugs in the form of ionic liquid species. The main aim of this Review is to attract a broad audience of chemical, biological, and medical scientists to study advantages of ionic liquid pharmaceutics. Overall, the discussed data highlight the importance of the research direction defined as "Ioliomics", studies of ions in liquids in modern chemistry, biology, and medicine.

Alkyl(C16, C18, C22)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).

Biodegradable herbicidal ionic liquids based on synthetic auxins and analogues of betaine

Herbicidal ionic liquids derived from alkylbetaines proved to be biodegradable, thermally stable and highly effective anti-weed agents.

Ionic liquids based on bromoxynil for reducing adverse impacts on the environment and human health

Many herbicides exhibit some disadvantages such as high water solubility and volatility after application, which lead to potential threats to the aquatic and atmospheric environment and human health.

Influence of oligomeric herbicidal ionic liquids with MCPA and Dicamba anions on the community structure of autochthonic bacteria present in agricultural soil

The aim of this study was to evaluate the impact of selected herbicidal ionic liquids (HILs), which exhibit high efficacy in terms of weed control and low toxicity, but may be persistent due to limited biodegradability, on the community structure of autochthonic bacteria present in agricultural soil. Four different oligomeric HILs (with two types of cations and different ratio of herbicidal anions) were synthesized and characterized by employing (1)H and (13)C NMR. The results of biodegradation assay indicated that none of the tested HILs could be classified as readily biodegradable (biodegradation rate ranged from 0 to 7%). The conducted field studies confirmed that the herbicidal efficacy of the HILs was higher compared to the reference herbicide mixture by 10 to 30%, depending on the dose and weed species. After termination of field studies, the soil treated with the tested HILs was subjected to next generation sequencing in order to investigate the potential changes in the bacterial community structure. Proteobacteria was the dominant phylum in all studied samples. Treatment with the studied HILs resulted in an increase of Actinobacteria compared to the reference herbicidal mixture. Differenced among the studied HILs were generally associated with a significantly higher abundance of Bacteroidetes in case of 1-HIL-Dicamba 1/3 and Firmicutes in case of 2-HIL-Dicamba 1/3.

Herbicidal ionic liquids derived from renewable sources

A new family of herbicidal ionic liquids based on d-glucose and MCPA or 2,4-D anions has been synthesized and the physicochemical, surface active and herbicidal properties of the obtained salts were characterized.

Pyrrolidinium herbicidal ionic liquids

In this work, sixteen new pyrrolidinium herbicidal ionic liquids (HILs) with phenoxycarboxylate anions were synthesized and characterized.

Synthesis, properties and evaluation of biological activity of herbicidal ionic liquids with 4-(4-chloro-2-methylphenoxy)butanoate anion

In this study, fourteen new herbicidal ionic liquids (HILs) based on MCPB with a 1-alkyl-1-methylpiperidinium cation were synthesized and characterized.

Ammonium ionic liquids with anions of natural origin

Ammonium ionic liquids with anions of natural origin are biodegradable agents with antifeedant and anti-microbial activity.