| Popis: |
Metal doping plays important role in increasing catalytic activity of catalyst materials. In this work, Ca and K were doped to the γ-Al 2 O 3 by dry impregnation method to study the crystallinity, surface area, activation energy, and yield in the coconut oil transesterification reaction. The success of doping was shown in the characterization of Ca/γ-Al 2 O 3 and K/γ-Al 2 O 3 using X-Ray Diffraction (XRD) which increasing in crystallinity from 62.2% (γ-Al 2 O 3 ) to 69.3 (K/γ-Al 2 O 3 ) and 76.0 (Ca/γ-Al 2 O 3 ). The emerging peak of 2θ characteristics of K (29.70° and 32.65°) and Ca (25.35°, 26.77°, and 27.17°) on the γ-Al 2 O 3 (37.66°, 45.82° and 67.22 °) was also observed. Characterization by the Surface Area Analyzer (SAA) shows that the K/γ-Al 2 O 3 catalyst has a smaller surface area (34.03 m 2 /g) than Ca/γ-Al 2 O 3 (83.77 m 2 /g), but a higher pore diameter (66.12 A) than Ca/γ-Al 2 O 3 (35.22 A). The K/γ-Al 2 O 3 catalyst produced greater FAME yield (93.19%) than Ca/γ-Al 2 O 3 (29.76%) at a catalyst concentration of 2.5%, reaction time 150 s, and ultrasonic frequency of 40 kHz. The quality of the FAME catalyzed by K/γ-Al 2 O 3 fulfills four test parameters: density, kinematic viscosity, flash point, and pour point according to SNI 04-7182-2006 standards. |
