Studies on the Binary MgO/SiO2 Mixed Oxide Catalysts for the Conversion of Ethanol to 1,3-Butadiene

Abstract

The demand for 1,3-butadiene, one of the most important raw materials in the rubber industry, is constantly increasing. The Lebedev process is a classical method of producing 1,3-butadiene from ethanol, which is to be optimized with regard to the mixed oxide catalysts used. In this work, the binary MgO/SiO2 solid system was tested with regard to its optimum chemical composition for the catalytic conversion of ethanol to 1,3-butadiene. Furthermore, novel mesoporous mixed oxides were prepared to investigate their textural, structural, and surface chemical properties as well as the catalytic activity. Nitrogen physisorption, scanning electron microscopy (SEM), and temperature-programmed ammonia desorption (NH3-TPD) measurements were carried out and evaluated. It was shown that the optimum yield of 1,3-butadiene is achieved by using MgO/SiO2 mixed oxide catalysts with 85–95 mol% MgO and not, as suggested by Lebedev, with 75 mol% MgO. The NH3-TPD measurements revealed that the maximum acid-site density is achieved with an equimolar up to magnesium-rich composition. During the synthesis of binary MgO/SiO2 solid systems based on mesoporous MgO, a thermally stable and ordered structure was formed in the autoclave, depending on the carbonate used and on the duration of the treatment.

A study of the conversion of ethanol to 1,3-butadiene: effects of chemical and structural heterogeneity on the activity of MgO–SiO2 mixed oxide catalysts

“…1 The potential of heterogeneous catalytic ETB process has even been demonstrated at industrial level. 2 The most commonly used supports/catalysts for the reaction are mixed oxides, such as MgO-SiO 2 3,4,[13][14][15][16][17][18][19][20][21][22]5,[23][24][25][26][27][28][29][6][7][8][9][10][11][12] or ZrO 2 -SiO 2 [30][31][32][33][34] , and their derivatives, obtained through modification by metals, such as, Ag 4,27,31,35,36 , Cu 16,27,33 , and Au 10 , or by metal oxides ZrO 2 9,36,37 , ZnO 9,16,19,23,…”

Mechanistic Insights into the Meerwein–Ponndorf–Verley Reaction and Relative Side Reactions over MgO in the Process of Ethanol to 1,3-Butadiene: A DFT Study

“…With the rapid development of biomass energy such as lignin, cellulose, and hemicellulose, ethanol has been widely developed and adopted as a renewable energy resource. Many valuable chemical products have been made based on ethanol, especially 1,3-butadiene, proposed by Lebedev and Ostromislensky , to provide raw materials for downstream rubber products. , The mechanism of aldol condensation in the process of ethanol to 1,3-butadiene is well-accepted, − consisting of the ethanol dehydrogenation, aldol condensation, Meerwein–Ponndorf–Verley (MPV) reaction, and dehydration reaction, where a multifunctional catalyst is needed for different reaction steps. , The surface of MgO catalyst has both acid and base properties, which makes MgO catalyst a versatile catalyst and profoundly impacts the process of ethanol to 1,3-butadiene as an effective component. ,, It is likely most difficult for the MPV reaction to understand the mechanism due to the presence of Lewis acid sites …”

“…4,5 The mechanism of aldol condensation in the process of ethanol to 1,3-butadiene is well-accepted, 6−9 consisting of the ethanol dehydrogenation, aldol condensation, Meerwein−Ponndorf− Verley (MPV) reaction, and dehydration reaction, where a multifunctional catalyst is needed for different reaction steps. 10,11 The surface of MgO catalyst has both acid and base properties, which makes MgO catalyst a versatile catalyst and profoundly impacts the process of ethanol to 1,3-butadiene as an effective component. 10,12,13 It is likely most difficult for the MPV reaction to understand the mechanism due to the presence of Lewis acid sites.…”

Direct SVUV-PIMS identification of unstable oxygenated intermediates in ethanol to butadiene reaction

“…MgO-SiO 2 , which was reported as the best catalyst for butadiene formation from ethanol, [24][25][26] as well as MgO and SiO 2 , was selected as catalysts for ethanol to butadiene conversion and acetaldehyde condensation in this work. The characterization results showed that the prepared catalyst was consistent with previous reports, and the two components were dispersed well (Fig.…”