Crystal growth study of nanosized K-MER zeolite from bamboo leaves ash and its catalytic behaviour in Knoevenagel condensation of benzaldehyde with ethyl cyanoacetate

• Main Authors: Cheong, Ying-Wai, Rigolet, Severinne, Daou, T. Jean, Wong, Ka-Lun, Ling, Tau Chuan, Ng, Eng-Poh
• Format: Article
• Published: Elsevier Science Sa 2020
• Subjects: Q Science (General); QD Chemistry
• Online Access: http://eprints.um.edu.my/36424/
• Institution: Universiti Malaya

A detailed study on the formation of nanosized K-MER zeolite from a template-free hydrogel system is reported. By using a new recipe and bamboo leave ash (BLA) as a reactive silica source, the K-MER zeolite crystallization time has been shortened from 15 days to 6 h at 180 degrees C, enabling the investigation of induction, nucleation and crystal growth of nanoscale K-MER zeolite using spectroscopy and microscopy techniques. The resulting zeolite nanorods ((45.1 +/- 14.5 nm length) x (3.9 +/- 1.9 nm width)) have a Si/Al ratio of 2.31 and they tend to assemble in parallel forming bulkier bundle-like secondary structure ((728 +/- 171 nm length) x (251 +/- 49 nm width). The nanocrystals (84.3% conversion and yield, 100% selective to ethyl 2-cyano-3-phenylacrylate (ECP)) show better catalytic performance than other homogeneous base catalysts (92-99% conversion, 82-84% yield) in Knoevenagel reaction of benzaldehyde and ethyl cyanoacetate under non-microwave instant heating condition, thus offering an eco-friendly approach for synthesizing highly selective solid base catalyst for synthesizing pure fine chemicals.