Surface Activity Improvement Study Of [C₁₂mim][Br] And Solubilization Evaluation Of Cyhalothrin

In agricultural production,pesticides are a great significance for people to control pests and diseases and regulate plant growth.However,the active ingredient is usually waterless.More and more researchers have paid attention to the solubilization of pesticides in ionic liquid surfactants.Ionic liquid surfactants usually have both the long alkyl chains and a hydrophilic head group,which could show amphiphility.Imidazolyl ionic liquid surfactants have high stability and low melting point,and they are the most widely studied to date.Compared to 1,3-alkylimidazole cations,1,2,3-imidazole is more stable and has a higher hydrophobic capacity.The traditional surface-active ionic liquid 1-dodecyl-3-methylimidazolium bromide[C₁₂mim][Br]is already a well-known ionic liquid.Because of its simple synthesis method and low cost,it has been applied in many fields.With the improvement of people’s quality of life,production is becoming more and more environmentally friendly and efficient.Therefore,it is necessary to improve the surface activity and greenness of[C₁₂mim][Br].Amino acid is the basic unit of protein,and it can also be used as anion in ionic liquid.Due to its biological characteristics,the ionic liquid composed of amino acid has low biological toxicity and is green and environmentally friendly.It belongs to a new type of green ionic liquid.Deep eutectic solvent,DES,has the characteristics of designability and greenness,and has gradually developed as a new solvent to replace traditional flammable and toxic organic solvents.Previous studies have shown that DES can act as a hydrotrope to affect the self-assembly behavior of amphiphiles.Therefore,three schemes are designed in this paper to improve the surface activity of[C₁₂mim][Br]and reduce the biological toxicity.Scheme 1:Change the cationic alkyl chain,replace1,3-alkylimidazolium cation with 1,2,3-alkylimidazolium cation,and improve its surface activity.Scheme 2:Change the counter ion and replace bromide ion with amino acid anion to reduce biological toxicity.Scheme 3:Use the green solvent tetrabutylammonium bromide:ethylene glycol 1TBAB:3EG as a hydrotrope to improve greenness.Finally,to explore the application value in the field of pesticides,the solubilization effect of six kinds of aqueous solutions on the insecticide Cyhalothrin was determined.The specific experiment content is as follows:1.In order to improve the stability,environmental protection and surface activity of[C₁₂mim][Br],three ionic liquid surfactants were designed and established:1-dodecyl-2,3-dimethylimidazolium bromide（[DMDIm][Br]）.1-dodecyl-2,3-dimethylimidazolium propionic amino acid（[DMDIm][Ala]）,1-dodecyl-2,3-dimethylimidazolphenylpropylamino acid（[DMDIm][Phe]）,and the above ionic liquid was characterized by ¹H NMR and TG.In addition,the DES（1TBAB:3EG）was also synthesized and characterized by FT-TR and TG.2.Based on the amphiphility of ionic liquid surfactants,the CMC and thermodynamic parameters of[C₁₂mim][Br],[DMDIm][Br],[DMDIm][Ala]and[DMDIm][Phe]in aqueous solution were obtained by conductivity method and volume method,and the effects of anions and cations on ionic liquid surfactants were discussed.Secondly,the influence of the chemical structure on the hydration behavior of ionic liquids was discussed through density experiments and viscosity experiments.Finally,through DLS experiments,the aggregate size of the above-mentioned ionic liquids in aqueous solution was observed.3.In order to explore the potential of DES as a self-assembly"design"medium,[DMDIm][Br]and DES aqueous solution were formulated into a hybrid system,and the CMC of the mixed solution was determined by conductivity method.To study the effect of DES on the self-assembly of[DMDIm][Br]in solution and its concentration,DLS experiments are used to determine the size of aggregates.4.Pyrethroids are a class of insecticides that simulate natural pyrethroids by artificial synthesis,and the active ingredient is natural chrysanthemum,however,it has insoluble nature.Therefore,we provide six protocols to dissolve cyhalothrin,calculate solubility by UV spectrophotometer,and analyze the solubilization mechanism.