preparation of a superior liquid catalyst by hybridization of three solids of nanozno, urea, and choline chloride for knoevenagel-based reactions

The complex catalyst of [znclo.urea]−[ch.urea]+ has been prepared by dissolving of nanozno in choline chloride:2urea at 50 °c. the concentration of [znclo.urea]− in the given liquid is 19,987 ppm and 10.5 times higher than similar solution made from bulk zno. this organic/inorganic hybrid catalyst represents a high catalytic performance in knoevenagel-based synthesis of pyrans, chromenes, and electron-deficient alkenes. due to the high diffusion of zno nanoparticles in dess, synergy of nanozno with dess, and much contact of this fluid catalyst with starting materials, all knoevenagel-based reactions occur with higher yields at lower catalyst loading and shorter times than individual chcl:2urea, nanozno, or even previously catalysts used for this purpose. high polarity and reusability are other advantages of anionic complex [znclo.urea]− and homogenized shape of nanozno.