l-Lysine Functionalized Polyacrylonitrile Fiber: A Green and Efficient Catalyst for Knoevenagel Condensation in Water

Functionalized Nylon 6 Fabric as an Efficient and Recyclable Catalyst for Knoevenagel Condensation

Nylon 6 fabrics were chemically modified via reduction with BH₃ for being functionalized as heterogeneous base organocatalysts for Knoevenagel condensation. The results of FTIR, XPS, and SEM indicated the successful modification of nylon 6 fabrics. With a low catalytic dosage of 6.6 mol % and a short reaction time (2 h), the fabric catalysts were well applicable to Knoevenagel condensation of a wide range of substrates and up to 98% yield could be obtained. In addition, the fabric catalysts have some beneficial advantages in terms of easy separation, good reusability, and recyclability (up to 10 times).

Ag2CO3 containing magnetic nanocomposite as a powerful and recoverable catalyst for Knoevenagel condensation

In this paper, the synthesis, characterization and catalytic application of a novel magnetic silica-supported Ag2CO3 (MS/Ag2CO3) with core-shell structure are developed. The MS/Ag2CO3 nanocomposite was prepared through chemical modification of magnetic MS nanoparticles with AgNO3 under alkaline conditions. The structure, chemical composition and magnetic properties of MS/Ag2CO3 were investigated by using VSM, PXRD, FT-IR, EDX and SEM techniques. The MS/Ag2CO3 nanocomposite was used as an effective catalyst for the Knoevenagel condensation under solvent-free conditions at 60 °C in an ultrasonic bath. The recovery and leaching tests were performed to study the nature of the MS/Ag2CO3 catalyst under applied conditions.

Synthesis and styrene copolymerization of novel trisubstituted ethylenes: 3. Alkoxy ring-substituted isopropyl 2-cyano-3-phenyl-2-propenoates

Novel trisubstituted ethylenes, alkoxy ring-substituted isopropyl 2-cyano-3-phenyl-2-propenoates, RPhCH = C(CN)CO₂CH(CH₃)₂ (where R is 2-methoxy, 3-methoxy, 4-methoxy, 2-ethoxy, 3-ethoxy, 4-ethoxy, 4-propoxy, 4-butoxy, 4-hexyloxy) were prepared and copolymerized with styrene. The ethylenes were synthesized by the piperidine catalyzed Knoevenagel condensation of ring-substituted benzaldehydes and isopropyl cyanoacetate, and characterized by CHN analysis, FTIR, ¹H and ¹³C NMR. All the ethylenes were copolymerized with styrene in solution with radical initiation (ABCN) at 70°C. The compositions of the copolymers were calculated from nitrogen analysis and the structures were analyzed by FTIR, ¹H and ¹³C NMR. Decomposition of the copolymers in nitrogen occurred in two steps, first in the 250-500ºC range with residue (2.6–3.9% wt.), which then decomposed in the 500-800ºC range.