Preparation of cancrinite-type zeolite from diatomaceous earth as transesterification catalysts for biodiesel production

A new type of solid catalyst prepared from hydrothermal reaction of natural diatomaceous earth in NaOH solution was studied for biodiesel production through the transesterification of soybean and palm oil in excess methanol. Explicitly, the natural diatomite was transformed into efficacious catalysts, sequentially, by dispersion and activation in NaOH solutions for 30 min at 30 degrees C, followed by hydrothermal treatments at 180 degrees C or 220 degrees C for 12 h, and finally by calcination at 500 degrees C for 6 h. Coincidently, the physicochemical characteristics of these as-prepared catalysts were shown to bear a good resemblance with those of zeolite CAN. Under suitable conditions, the conversion efficiencies of soybean and palm oils to biodiesel in presence of these zeolite CAN catalysts at 63 degrees C and 70 degrees C could be obtained as high as 98.0% and 98.4%, respectively. Furthermore, the activation energies of the transesterification reactions of soybean and palm oils in excess methanol were found as 64.1 kJ/mol and 122.5 kJ/mol, respectively. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

A new type of solid catalyst prepared from natural diatomaceous earth showed high conversion efficiency in transesterification reactions of soybean and palm oil. The catalyst, after dispersion and activation in NaOH solution, hydrothermal treatment, and calcination, exhibited characteristics resembling zeolite CAN.