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Hamza M. Abosadiya,Siti Aishah Hasbullah,Jumina,Bohari M. Yamin 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.12
C-4-acetamidophenylcalix[4]-2-methylresorcinarene was synthesized by condensation reaction of 2-methylresorcinol with 4-acetamidobenzaldehyde in the presence of concentrated HCl. The compound was characterized by infrared (IR), 1H, and 13C NMR spectroscopy. Single crystal X-ray analysis revealed that the molecule crystallized in a triclinic crystal system with space group of Pī and the unit cell dimensions are a = 8.929(1) Å, b = 13.804(2) Å, c = 14.471(2) Å, α = 76.766(4)°, β = 78.563(4)°, γ = 87.168(4)°, Z = 1, and V = 1702.0(4) Å3. The calix molecule is associated with four dimethylsulfoxide (DMSO) and two water molecules of crystallization that contribute to the stability of the solid via hydrogen bonding. The supramolecule adopts a chair (C2h ) conformation with four phenyl linkage groups that are in rctt (cis–trans–trans) configuration isomer. The thermal gravimetric investigation showed three mass loss steps that occurred at about 100, 400, and 900 °C, respectively. The compound formed after the first loss is thermally stable in the range of 100–400 °C after which the calix moiety began to decompose.
Jumina,Ifa Amalina,Sugeng Triono,Yehezkiel Steven Kurniawan,Yoga Priastomo,Keisuke Ohto,Bohari M. Yamin 대한화학회 2021 Bulletin of the Korean Chemical Society Vol.42 No.3
At present, biodiesel remains an untapped fuel source while crude oil reserves are being depleted. Extensive efforts are necessary to achieve efficient biodiesel production, but catalytic activity in methyl palmitate production remains unsatisfactory. In this study, we report the synthesis and organocatalyst activity of C-arylcalix[4]-2-methylresorcinarene sulfonic acids for biodiesel production. The presence of a methyl group on an aromatic ring is expected to disturb the intramolecular hydrogen bonds; thus, each hydroxyl group could be utilized for the catalytic process. C-arylcalix[4]-2-methylresorcinarene sulfonic acids were prepared from cyclocondensation and sulfonation reactions yielding compounds 1?6 at rates of 66.7%?86.6%. By evaluating the organocatalytic activity of the C-arylcalix[4]-2-methylresorcinarene sulfonic acids, we found that 4?mol% of compound 5 exhibited the highest yield (97.8%) of methyl palmitate at 338?K for 6-h reaction time, which is remarkable. These findings show that C-arylcalix[4]-2-methylresorcinarene sulfonic acids are promising heterogeneous catalyst materials for biodiesel production.