A Box-Behnken design for determining the optimum experimental condition of the fungicide (Vapam) sorption onto soil modified with perlite

In the present study, response surface methodology (RSM) based on the Box-Behnken design (BBD) was employed to investigate the effects of the different operating conditions on the removal of the fungicide (Vapam) onto soil modified with perlite using sorption process. The process parameters such as pH of the fungicide solution (2, 5 and 8), temperature (15, 25 and 35°C), shaking time (2, 13 and 24 h) and the percentage of perlite in the modified soil (0, 2 and 4 %) were investigated using a four-factor-three-level Box-Behnken design at an initial fungicide concentration of C₀ = 1.6 mg/L as a fixed input parameter. A second-order quadratic model suggested the optimum conditions to be as follows: fungicide solution pH of 3.57, temperature of 15°C, shaking time of 3.5 h and 4% of perlite in the modified soil which resulted in the improvement of Vapam sorption. Under optimum conditions, the fungicide (Vapam) removal was predicted 12.88 μg/g by BBD. The confirmatory experiments were conducted and the results revealed that the fungicide removal was 13.14 μg/g which indicated that the predicted and the observed values of response (Vapam removal) were in close agreement. Therefore, the soil modified with perlite holds good potential for Vapam sorption. This is the first report on fungicide Vapam sorption onto soil modified with perlite using statistical experimental design employing response surface methodology.     

Fast 62–92 % yield preparation of amino acid dithiocarbamates in green solvent at room temperature

Dithiocarbamate and their derivatives are of importance in medicinal chemistry due to their biological activities, in agriculture as fungicides and in organic synthesis as versatile synthetic intermediates. Green solvents such as deep eutectic solvents and polyethylene glycol are new emerging alternatives to conventional harmful organic solvents. Here, we report the synthesis of amino acid–based dithiocarbamates by one-pot three-component reaction of the electrophilic reagent, carbon disulfide and α-amino acids in deep eutectic solvent and polyethylene glycol as a catalyst and reaction media. In situ preparation of dithiocarbamates by the reaction of different amino acids and carbon disulfide, followed by addition reaction with epoxides, alkyl halides and α, β-unsaturated enones at room temperature, gave the corresponding products in 62–92 % yield with a short reaction time without any tedious workup procedures. The deep eutectic solvents and polyethylene glycol were recycled without activity or yield decrease. Therefore, the synthesis of amino acid–based dithiocarbamates in green solvents is a promising alternative to previously used procedures.