Design of Effective Catalysts Based on ZnLaZrSi Oxide Systems for Obtaining 1,3-Butadiene from Aqueous Ethanol

Abstract

ZnLaZrSi oxide systems prepared with a silica component of the different nature have been studied in 1,3-butadiene production from aqueous ethanol. The following silica materials were used: KSKG, A-175, A-380, SBA-15, MCM-41, MCM-48, MCF and dealuminated BEA zeolites. The characteristics of the porous structure of the silica support, such as porosity, pore size distribution, specific and external surface areas, were found not to be critical parameters for achieving a high 1,3-butadiene yield during the EtOH-H 2 O mixture conversion in the presence of ZnLaZrSi oxide catalysts. On the contrary, the quantity and strength of Lewis acid sites, which in turn differ depending on the choice of silica material, have a significant impact on 1,3-butadiene selectivity and yield. The highest values of the selectivity of 1,3-butadiene formation (up to 68 %) and yield as well as stability toward deactivation in the presence of H 2 O were achieved over ZnLaZr-KSKG, ZnLaZr-SBA-15 and ZnLa-Zr 1 SiBEA (with mononuclear isolated tetrahedral Zr(IV) species). The productivity of ZnLa-Zr 1 SiBEA catalyst accounts for 0.324 g 1,3-BD •g cat -1 •h -1 (T = 648К, WHSV = 2.88 h -1 , 80 vol% EtOH in water as an EtOH source). The main reason for the decrease in 1,3-butadiene yield in the presence of H 2 O in the reaction mixture was shown to be a deactivation of acetaldehyde condensation sites on the catalyst surface, while the rate of acetaldehyde formation decreases slightly. According to 1 H-13 C CP/MAS NMR spectroscopic results, the use of aqueous ethanol as the feed for ETB-process is very advantage to prevent the carburization of the catalysts.= 2.88 h -1 , 80 vol% EtOH in water as an EtOH source). Therefore, for industrial realization of ETB process the development of the effective catalysts based on dealuminated BEA zeolites is also promising. ASSOCIATED CONTENTSupporting Information. The following file is available free of charge. 29Si and 1 H -29 Si CP MAS NMR spectra of ZnLa-Zr 3 SiBEA sample, SEM images of the ZnLaZrSi samples at three magnifications, the indices of EtOH-water mixture conversion in the presence of ZnLaZrSi oxide systems, the indices of ETB process in the presence of 2 %ZnO/6 %ZrO 2 -KSKG (DOCX).

Efficient separation of 1,3‐butadiene fromC4hydrocarbons by flexible metal–organic framework with gate‐opening effect

“…1,3‐Butadiene (C 4 H 6 ) is one of the basic and important raw material for petrochemical industry, which not only can be used in the production of synthetic rubber, but also in the synthesis of synthetic resins and other organic chemical products, such as tetramethylene sulfone, tetrahydrofuran 1–4 . It is mainly obtained from the by‐product of vapor cracking of naphtha 5 .…”

Selective direct conversion of aqueous ethanol into butadiene via rational design of multifunctional catalysts

“…23 However, when more than 5% water was present in the ethanol feedstock, the catalytic activity and BD selectivity were significantly declined. [24][25][26][27] Thus, the development of highly efficient catalysts for the direct conversion of aqueous ethanol (mixtures containing 80% ethanol) to BD (AETB) is of great significance to improve the BD production.…”

“…24,29,32 However, previous reports revealed that water had no significant effect on the ethanol dehydrogenation reaction, but the aldol condensation of acetaldehyde on LAS was significantly inhibited, resulting in the accumulation of acetaldehyde, and the subsequent reactions could not proceed. [24][25][26][27] In addition, the aldol condensation of acetaldehyde has proved to be the ratedetermining step in the direct conversion of ethanol to BD. 33 Therefore, rational coupling of these active centers is essential to improve the BD production from aqueous ethanol.…”

One-Pot Hydrothermal Synthesis of Multifunctional ZnZrTUD-1 Catalysts for Highly Efficient Direct Synthesis of Butadiene from Ethanol

“…Based on the studies of various catalytic systems until now, mixed acid–base binary oxides, that is, MgO–SiO 2 , ZrO 2 –SiO 2 , or Y 2 O 3 –SiO 2 , have been reported to be effective for C–C bond coupling, and these binary oxides doped with dehydrogenation centers (i.e., Cu, Ag, and Zn) are effective for direct ETB conversion. − Among these catalysts, ZnZr-/SiO 2 -based catalysts have received widespread attention because of their robust activity and potential foundation for the expansion of industrial catalysts for direct ETB conversion . However, the high concentration of silanol groups on the surface of SiO 2 can cause the side reaction of ethanol dehydration to ethylene and diethyl ether .…”