The catalytic etherification of EG with methanol has not been extensively reported in the literature. Scheffel et al. used H 2 SO 4 as the catalyst,
the conversion of EG was 61.2%, and the concentration of dimethoxyethane was only 9.9% in the mixture solution, less than that of 2-methoxyethanol
(23.5%). 18 Due to the environmental impact by liquid acid, solid acid has been reported for its application in the etherification reaction.
Baimbridge et al. used Nafion 15 as a catalyst for etherification of EG with methanol, and selectivity for 2-methoxyethanol and dimethoxyethane was
67% and 28%, respectively, with 75.7% of EG conversion.19 Ikariya et al. used s–Si–P (1 : 5 : 0.8) oxide catalyst to obtain 2-methoxyethanol with
76% selectivity at 23% conversion under 300 C and
12 MPa. However, dimethoxyethane was not detected in the products under these harsh conditions. 20,21 From the abovementioned reports, we found that
2-methoxyethanol was the main product during the etherification of EG with methanol, and it could not be efficiently converted to dimethoxyethane
further, which resulted in low yield. Another finding from the abovementioned reports was that the by-product 1,4-dioxane was detected. EG was easily
activated in the presence of an acid catalyst, and self-etherification would finally form 1,4-dioxane.22,23 In addition, the etherification of EG with
methanol is an equilibrium reaction. |
