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There is an urgent need to develop green catalytic transesterification technology to reduce liquid waste and instrument corrosion. Ionic liquids with controlled activity, easy recovery, and corrosion resistance have great potential as catalysts for transesterification reactions. In this paper, a series of ionic liquids were prepared using imidazole and ammonium compounds as cations, and sulphuric acid, p‐toluenesulfonate, and bistrifluoromethanesulfonate anions as anions. In comparison, the ionic liquid made from imidazole with H2SO4 (IMIHS) was found to be the best catalyst for the esterification reaction with high speed, high activity, low corrosion, and high stability, and its catalytic performance was superior to that of sulphuric acid. The optimum reaction conditions were as follows: the molar ratio of ethanol to acetic acid was 1:1, the catalyst amount was 5 wt.%, the reaction temperature was 80°C, and the reaction time was 120 min. The maximum yield of ethyl acetate was 66.2% under the optimum reaction conditions. The catalytic activity was not declined obviously by reusing six times. The activation energy of the reaction is 48.748 kJ/mol. [ABSTRACT FROM AUTHOR]

In this paper, we present the synthesis of new selenoloquinoxaline derivatives starting from 2‐chloroquinoxaline‐3‐carbonitrile 1. The compound 1 was subjected to a reaction with selenium metal in the presence of NaBH4 as a reducing agent in ethanol, under a nitrogen atmosphere. This reaction resulted in the formation of the sodium salt of 3‐cyanoquinoxaline‐2‐selenolate, which was subsequently reacted with α‐halogenated carbonyl compounds in situ. This reaction produced a series of newly synthesized 3‐aminoselenolo[2,3‐b]quinoxaline‐2‐substituents. Ethyl 3‐aminoselenolo[2,3‐b]quinoxaline‐2‐carboxylate 3a was hydrolyzed by sodium hydroxide to give the corresponding sodium salt 9. This salt was then refluxed with acetic anhydride to produce oxazinone compound 10. The reaction of compound 10 with ammonium acetate afforded pyrimidoselenolo[2,3‐b]quinoxaline derivative 11. Compound 11 was then chlorinated using phosphorous oxychloride to give the corresponding chlorocompound. [ABSTRACT FROM AUTHOR]

Spray water quality parameters such as hardness, pH, alkalinity, turbidity, and total dissolved solids (TDS) can influence the performance of herbicides. Polyvalent cations found in hard water can reduce the efficacy of post‐emergence herbicides that are weak acids. Various approaches have been proposed to mitigate the negative effects of spray water properties on herbicide performance. Water conditioning adjuvants are designed for overcoming the adverse effects of hard water. One group of adjuvants are nitrogen containing compounds such as ammonium sulfate (AMS). The ability of AMS to overcome hard water antagonism is well‐documented but the positive effect of other ammonium compounds are variable and depend on herbicides and weed species. Other adjuvant groups that can overcome effects of poor spray quality are ethoxylated amine surfactants, organic acids and ethylenediaminetetraacetic acid (EDTA). Water quality is poor in many parts of the world, and accordingly, the study of water property effects on herbicide performance is needed to optimize use, and prevent overuse, of herbicides. [ABSTRACT FROM AUTHOR]