Oxidation of Bioethanol using Zeolite‐Encapsulated Gold Nanoparticles

Abstract

With the ongoing developments in biomass conversion, the oxidation of bioethanol to acetaldehyde may become a favorable and green alternative to the preparation from ethylene. Here, a simple and effective method to encapsulate gold nanoparticles in zeolite silicalite-1 is reported and their high activity and selectivity for the catalytic gas-phase oxidation of ethanol are demonstrated. The zeolites are modified by a recrystallization process, which creates intraparticle voids and mesopores that facilitate the formation of small and disperse nanoparticles upon simple impregnation. The individual zeolite crystals comprise a broad range of mesopores and contain up to several hundred gold nanoparticles with a diameter of 2-3 nm that are distributed inside the zeolites rather than on the outer surface. The encapsulated nanoparticles have good stability and result in 50 % conversion of ethanol with 98 % selectivity toward acetaldehyde at 200 8C, which (under the given reaction conditions) corresponds to 606 mol acetaldehyde/mol Au hour À1 .

Tailoring the Surface Structure of Silicon Carbide Support for Copper Catalyzed Ethanol Dehydrogenation

“…Acetaldehyde, with a worldwide production exceeding 10 6 tons/year, is an important organic intermediate in chemical industry to produce high value‐added fine chemicals, such as 1‐butanol, 2‐ethylhexanol, pyridine bases, and chloral . Currently, the main route for acetaldehyde production is the Wacker process, via ethylene oxidation catalyzed by PdCl 2 and CuCl 2 in strong acidic solutions ,. Nevertheless, the resource constraints and environmental requirement make the dehydrogenation of e thanol to a cetaldehyde (DHEA), a particularly attractive and green alternative to ethylene route.…”

A Highly Porous Carbon Support Rich in Graphitic‐N Stabilizes Copper Nanocatalysts for Efficient Ethanol Dehydrogenation

“…Ethanol can be converted into acetaldehyde and hydrogen through a direct dehydrogenation protocol, usually named the dehydrogenation of ethanol to acetaldehyde process (DHEA) . This process is more promising than oxidation dehydrogenation of ethanol, which produces CH 3 COOH, CO 2 , CH 4 , and other byproducts . Compared with the current industrial Wacker process, which involves the use of PdCl 2 and CuCl 2 as catalysts in strong acidic and corrosive solutions, the DHEA process may become an important alternative for the production of acetaldehyde .…”

Highly Selective Copper Catalyst Supported on Mesoporous Carbon for the Dehydrogenation of Ethanol to Acetaldehyde

“…The increase of alternative energy produced from renewable biomass and its derivatives helps to alleviate our dependence on fossil resources 1. 2 Ethanol, which is obtained easily from biomass fermentation,3 is particularly attractive because of its increased annual production and low cost 4. 5 In synthetic chemistry and the fine chemical industry, ethanol is utilized widely for the production of hydrogen, acetic acid, 1‐butanol, ethyl acetate, 1,3‐butadiene, acetaldehyde, and other chemicals 4.…”

“…2 Ethanol, which is obtained easily from biomass fermentation,3 is particularly attractive because of its increased annual production and low cost 4. 5 In synthetic chemistry and the fine chemical industry, ethanol is utilized widely for the production of hydrogen, acetic acid, 1‐butanol, ethyl acetate, 1,3‐butadiene, acetaldehyde, and other chemicals 4. 6–12 In particular, acetaldehyde, a significant bulk chemical, is valuable for the production of peracetic acid, pentaerythritol, pyridine bases, butanediol, and trichloroacetic aldehyde, with a worldwide production over 10 6 tons per year 13.…”

“…As hydrogen is the sole byproduct, the dehydrogenation of ethanol to acetaldehyde (DHEA)11, 12, 15 represents an atom‐economic process,8, 9, 16 which is a more favorable and green alternative to the current Wacker process of oxidation ethylene to make acetaldehyde using PdCl 2 and CuCl 2 as catalysts in strong acidic solutions 4. Currently, in industrial production and literature reports, SiO 2 ‐supported Cu catalysts are mainly used in DHEA because of the nearly neutral surface of SiO 2 compared with Al 2 O 3 , ZnO, and ZrO 2 .…”