Production of ethylene glycol monobutyl ether through etherification of ethylene glycol using a nanostructured heterogeneous catalyst of amyberlyst-15

This work aims to produce butyl glycol from the etherification of ethylene glycol (EG) and n-butanol (NB) using different heterogenous Amyberlyst-15 catalysts in a pressurized reactor tank. Experiments were designed by response surface methodology according to the central composite design (RSM-CCD). Three operating conditions of temperature (140-200 degrees C), reaction time (2-22 h), and EG: NB molar ratio (1:1-1:9) were considered to model and optimize the EG conversion under fixed pressure and catalyst weight. A quadratic conversion model was proposed as a function of independent and combined studied parameters, predicting the experimental data with high accuracy (R-2 > 0.98). According to the response surface results, all variables positively affected the response. The optimal reaction condition for maximizing conversion was at 1:8.2, 4.1 h, and 200 degrees C, achieving the EG conversion of 86.12 %. Furthermore, the catalyst reusability was checked after four cycles, indicating a reduction of about 15 % in conversion after each cycle. The FESEM, FTIR, XRD, BET, and TGA analyses characterized the fresh catalyst and used catalyst after the fourth cycle. Both samples had a spherical morphology, and the used catalyst contained carbon-based sediments, intensifying the stretching vibration of C-O bond peaks. The pore diameter and volume of the fresh catalyst were 18.93 nm and 2.38 cm(3)/g, respectively, while these values were 22.07 nm and 0.36 cm(3)/g for the used catalysts after the fourth cycle. The reduction in the catalytic activity of the used sample can be because of the pore deformation.