Preparation and modification of 13X zeolite as a heterogeneous catalyst for esterification of oleic acid
Balqees A. Alshahidy, Ammar S. Abbas
Abstract
In this study, the synthesis of 13X zeolite as a byproduct from Iraqi insoluble potash ores accompanied by potassium carbonate preparation was investigated. Citric acid efficiency, as dealuminated agent, was monitored for the prepared 13X zeolite by applying different experimental conditions, concentration (0.1 and 1 N), treatment temperature (25 and 75 °C), and time of reaction (1 and 3 h). Different techniques have been used in order to assess the effect of treatment with citric acid on the structural and textural properties of the obtained products, which are X-ray diffraction (XRD), X-ray Fluorescence (XRF), N2 adsorption-desorption Brunauer Emmett–Teller (BET) analysis, scanning electron microscope (SEM), and energy dispersive X-ray spectroscopy (EDX). The results of the XRD test revealed that dealumination with 1 N citric acid causes structural damages for the zeolite and transforms it into alpha quartz, while the XRD pattern was similar to that of prepared 13X zeolite when treated with 0.1 N citric acid. XRF data showed a significant improvement in the Si/Al ratio compared to the prepared 13X zeolite. Prepared and selected dealuminated catalysts were tested as a heterogeneous catalyst for the esterification reaction of oleic acid with ethanol at 70 °C for 1h. A higher oleic acid conversion was obtained using the modified 13X zeolite, as opposed to the direct use of the non-improved prepared catalyst.