Enhancing the dimethyl ether carbonylation performance over mordenite catalysts by simple alkaline treatment

Dimethyl ether carbonylation over zeolites

“…Fortunately, it was recently reported that alkaline treatment of the as-synthesized (uncalcined) mordenite that still contained the template (tetraethyl ammonium bromide) could protect the micropores and the acid sites in the 8-MR side pockets but also created a substantial fraction of mesopores. The resulting HMOR catalyst showed enhanced stability without obvious decrease in the activity for DME carbonylation; whereas alkaline treatment of the calcined sample resulted in a dramatic decrease in the formation rate of MA [95] .…”

“…The conversion of DME increased moderately from 37% over the original ZSM-35 to 44% after alkaline treatment [43] . Similarly, alkaline treatment of HMOR enhanced the activity and stability of DME carbonylation, possibly due to the generation of mesopores inside the zeolite crystals [94,95] . Upon treatment with 0.2 M aqueous NaOH solution at 65 °C for 0.5 h for HMOR (Si/Al ratio of 20), the formation rate of acetyls increased from 0.133 g mL −1 cat h −1 to 0.294 g mL −1 cat h −1 at time on stream of 140 h [94] .…”

Enhancing the dimethyl ether carbonylation performance over hydrogen-type mordenites modified by pyrazole hydrochloride

“…The absorption peak at 3660 cm À1 was corresponded to the O-H stretching vibration of the extraframework Al atoms. 11 The gure clearly shown that the intensity of the characteristic peak at 3660 cm À1 weakened as the concentration of the Pya$HCl solution increased, but when the concentration of the Pya$HCl solution was greater than 1.3 mol L À1 , the stretching vibration peak at 3660 cm À1 did not continue to weaken. This was consistent with the activity test results of the Pya$HCl-modied HMOR catalyst.…”

Recent Progress in Synthesis and Application of Nanosized and Hierarchical Mordenite—A Short Review

“…The usage of a microwave oven during the post-synthesis mordenite treatment led to increased conversion of α-pinene to 94.7% as a result of the selective extraction of silicon atoms and the retention of aluminum atoms (responsible for Brönsted acidity) located in the 12-membered channels. Another work investigated the alkaline treatment of two types of mordenite samples: the first containing the synthesis template (organic molecule) and the second after high temperature calcination [68]. The catalytic efficiency of both types of samples regarding dimethyl ether carbonylation remained approximately the same but a difference was observed in the extraction of Brönsted acid sites in the mordenite.…”