Sodium Methoxide/Zeolite-Supported Catalyst for Transesterification of Soybean Waste Cooking Oil for Biodiesel Production

This study aims to prepare a supported catalyst based on zeolite Y doped with NaOMe (sodium methoxide) for the transesterification of waste cooking oil (WCO). The catalytic screening data showed that NaOMe/zeolite is a prominent catalyst for the transesterification of WCO prepared by a solvent-free, ball-milling process. We initially tested 5-20% of sodium methoxide loading onto zeolite Y and found that 20% is the optimum loading for the reaction. The transesterification reaction required a comparatively lower methanol-to-oil mole ratio of 16:1 with the reaction temperature as 60 degrees C. The ball-milled NaOMe/zeolite catalyst was characterized by BET surface area analysis, FE-SEM, TEM, FT-IR, and XRD. The BET surface analysis revealed that the surface area for zeolite Y was substantially decreased in the NaOMe/zeolite catalyst. The ball-milling process dropped the crystallinity of zeolite Y, which can be seen from the XRD and FE-SEM images of both zeolite Y and the NaOMe/zeolite catalyst. Finally, the transesterification reaction product was fully characterized by 1H-NMR and viscosity analysis for biodiesel, glycerol, and the WCO. The chemical shifts for the biodiesel and glycerol are found accordingly. This is also supported by the FT-IR characteri-zation of biodiesel, glycerol, and WCO. It is noteworthy that a very high mass ratio of 250 g oil/g NaOMe is obtained when converting WCO to biodiesel, indicating very high catalytic activity for the aforementioned catalyst.

Automated summary

This study focuses on preparing a supported catalyst for the transesterification of waste cooking oil (WCO) by employing zeolite Y doped with sodium methoxide (NaOMe). The catalytic screening results demonstrate that NaOMe/zeolite prepared through a solvent-free, ball-milling process exhibits excellent catalytic activity. In particular, the optimal NaOMe loading on zeolite Y is found to be 20%. The transesterification reaction can be conducted with a lower methanol-to-oil mole ratio of 16:1 and a reaction temperature of 60 degrees C. The characterization of the ball-milled NaOMe/zeolite catalyst includes BET surface area analysis, FE-SEM, TEM, FT-IR, and XRD. The decrease in surface area and crystallinity of zeolite Y in the NaOMe/zeolite catalyst is observed. The transesterification reaction product is fully characterized by 1H-NMR and viscosity analysis, supported by FT-IR characterization. Remarkably, a high mass ratio of 250 g oil/g NaOMe is achieved, indicating the catalyst's high activity.