Membran pemangkin telah menarik perhatian penyelidik kebelakangan ini kerana ia menyediakan alternatif lebih baik berbanding pemangkin homogen dan heterogen. Paladium (Pd) ialah pemangkin popular yang biasa digunakan dalam tindak balas Suzuki-Miyaura. Membran matriks berasaskan Pd diperkenalkan dengan membran polimer, polisulfon (PSf) diperbadankan dengan partikel Pd bersama dua penstabil kimia yang berbeza, polivinilpirrolidon (PVP) dan polietilena glikol (PEG) untuk menstabilkan nanopartikel Pd. Empat sampel membran telah berjaya dihasilkan; PVP/PSf, 0.5gPVP/Pd/PSf, 1.0gPVP/Pd/PSf dan 1.0gPEG/Pd/PSf. Semua sampel membran telah menjalani proses pencirian. FTIR mengenal pasti perubahan kimia pada membran dan didapati semua sampel tidak banyak berubah secara kimia. SEM mengesan kecacatan pada permukaan dan keratan rentas membran dan sampel ditunjukkan tidak menunjukkan kecacatan di atasnya. Bagi EDX, kehadiran unsur Pd dikenalpasti dari membran dan sampel ditambah dengan nanopartikel Pd berjaya ditemui unsur Pd di dalamnya. Reaksi Suzuki-Miyaura telah dijalankan bersama semua empat sampel membran dengan menggunakan 4-bromoasetofenon dan asid fenilboronik sebagai bahan tindak balas. Antara sampel, 1.0gPVP/Pd/PSf telah menunjukkan prestasi pemangkin terbaik dengan mencapai hasil tertinggi produk, 4-asetilbifenil. Berbanding dengan 1.0gPEg/Pd/PSf, 1.0gPVP/Pd/PSf jelas mempunyai prestasi lebih baik dengan peratusan hasil adalah dua kali ganda. Ini menunjukkan bahawa kesan rintangan PVP adalah lebih rendah terhadap nanopartikel Pd berbanding PEG.
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Catalytic membrane has been caught the eye of the researchers in recent years as it provides a better alternative than homogenous and heterogeneous catalyst. Palladium (Pd) catalyst is a popular catalyst which normally used in Suzuki-Miyaura reaction. Pd based matrix membrane is introduced with polymeric membrane, polysulfone (PSf) is incorporated with Pd nanoparticles along two different chemical stabilizers, polyvinylpyrrolidone (PVP) and polyethylene glycol (PEG) that helped to stabilize the Pd nanoparticles. Four membrane samples have been successfully casted; PVP/PSf, 0.5gPVP/Pd/PSf, 1.0gPVP/Pd/PSf and 1.0gPEG/Pd/PSf. All the membrane samples have been undergone characterization process. FTIR identifies the chemical changes on the membranes and it is found that all the samples did not changed much chemically. SEM detects the defects on the surface and cross section of the membranes. From the results, it is shown that insignificant defect associated with the membranes. While for EDX, the presence of Pd element is identified and it is found that the catalytic membrane samples are successfully detected with Pd in it. Suzuki-Miyaura reaction was conducted with all the four membrane samples by using 4-bromoacetophenone and phenylboronic acid as reactants. Among the samples, 1.0gPVP/Pd/PSf has shown the best catalytic performance, achieving highest yield of product namely 4-acetylbiphenyl. When compared to 1.0gPEg/Pd/Psf, 1.0gPVP/Pd/PSf provides better performance with the yield percentage is about double. This shows that the hindrance effect of PVP is lower towards the Pd nanoparticles as compared to PEG.
PD nanoparticles in polymer thin film- hindrance evaluation / Teo Leong Her