81 Function of Surface Compounds in the Study of Catalytic Dehydration of Alcohols over Aluminum Oxide and Silica-Alumina Catalysts

Topchieva, K. V.; Yun-Pin, K.; Смирнова, Ирина

doi:10.1016/s0360-0564(08)60234-5

Cited by 30 publications

(4 citation statements)

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“…Conte et al have shown high selectivity of Al 2 O 3 - and SiO 2 -supported Zn 2+ catalysts for the ethylene hydrochlorination process . The structure of ethanol adsorbed on the alumina catalyst surface (surface ethoxide) was studied earlier. − The diethyl ether formation is favored with increased surface concentration of the ethoxide, suggesting that a Langmuir–Hinshelwood type of mechanism prevails due to ethoxide pairs on the surface . Topchieva et al suggested that the surface ethoxide is a reaction intermediate toward ethylene and diethyl ether …”

Section: Resultsmentioning

confidence: 99%

“…36 Topchieva et al suggested that the surface ethoxide is a reaction intermediate toward ethylene and diethyl ether. 39 In line with the formalism of Langmuir−Hinshelwood kinetics, simple primary surface reaction steps could be described as follows on Scheme2: A second, plausible Langmuir−Hinshelwood type of kinetic approach was developed for the ethyl alcohol chlorination, and a preliminary regression analysis was conducted in order to find out whether the approach might be a plausible one. The model assumes adsorption of ethanol onto the catalytic site as ethoxy species as well as the hydrochoric acid (steps I, II).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Continuous Gas-Phase Synthesis of 1-Ethyl Chloride from Ethyl Alcohol and Hydrochloric Acid Over Al₂O₃-Based Catalysts: The “Green” Route

Bukhan’ko

Samikannu

Larsson

et al. 2013

ACS Sustainable Chem. Eng.

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The synthesis of 1-ethyl chloride in the gas-phase mixture of ethanol and hydrochloric acid over ZnCl 2 /Al 2 O 3 catalysts was studied in a continuous reactor using both commercial and tailor-made supports. The catalytic materials were characterized by the means of structural (XPS, TEM, XRD, and BET) and catalytic activity (selectivity and conversion) measurements. The reaction parameters such as temperature, pressure, and feedstock flow rates were optimized for the conversion of ethanol to ethyl chloride. The new tailor-made highly porous Al 2 O 3 -based catalyst outperformed its commercial counterpart by exhibiting high conversion and selectivity (∼98%) at the temperature of 325°C. Long-term stability tests (∼240 h) confirmed the excellent durability of the tailor-made alumina catalysts. The process demonstrated here poses an efficient and economic "green" largescale on-site synthesis of this industrially important reactant in industry, where bioethanol is produced and 1-ethyl chloride is necessary, e.g., for ethylation of cellulose and synthetic polymer products. On-site in situ production of ethyl chloride avoids the problems associated with the transportation and storage of toxic and flammable 1-ethyl chloride.

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Section: Resultsmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%

Continuous Gas-Phase Synthesis of 1-Ethyl Chloride from Ethyl Alcohol and Hydrochloric Acid Over Al₂O₃-Based Catalysts: The “Green” Route

Bukhan’ko

Samikannu

Larsson

et al. 2013

ACS Sustainable Chem. Eng.

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“…Therefore, adequate temperature is necessary for ethanol dehydration on alumina. The key step of ethanol dehydration to ethylene on an alumina catalyst is ethanol's interaction with the surface Brønsted acid site (Al-OH) to form ethoxy intermediates [44], in which the surface OH group plays an important role. An in situ infrared experiment of ethanol dehydration showed that in the initial stage of the reaction, the disappearance of OH groups and emergence of ethoxy groups occurred simultaneously [26].…”

Section: Ethanol Dehydration 221 Catalytic Performancementioning

confidence: 99%

Ethanol Dehydration to Ethylene over High-Energy Facets Exposed Gamma Alumina

Wang

Peng

et al. 2023

Catalysts

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Highly efficient and stable catalysts are among the key factors in industrial ethanol dehydration to ethylene. Among the widely studied catalysts, alumina is the most suitable for industrial application. In this study, novel gamma alumina was synthesized by solvent protection and a hydrothermal procedure. HRTEM, XRD, FT-IR, NH3-TPD, H-D exchange, and 29Si MAS NMR were employed to compare the difference in physicochemical properties between the novel gamma alumina and commercial alumina. Characterization results show that the as-synthesized novel gamma alumina mainly exposes the high-energy crystal plane (111) while the commercial alumina mainly exposes the thermostatically stable (110) crystal plane. The dominating (111) plane, according to the characterizations, endows the novel gamma alumina with a higher density of surface hydroxyl groups, higher acid content, and higher surface energy compared to the commercial alumina. The catalytic performance of the two catalysts for industrial ethanol dehydration to ethylene was studied. The novel (111) plane-exposed alumina showed a higher yield of ethylene than commercial alumina under the same reaction conditions. This could be related to the difference in atomic arrangement and the unsaturated aluminum coordination of different crystal planes. Stability testing under severe reaction conditions (450 °C, 1 MPa, 4 h−1) indicates that novel gamma alumina shows better stability (catalyst life cycle increased by 50%) and produces less acetaldehyde as a byproduct. The effects of steam treatment on the catalytic performance were further investigated. The surface acidity and the catalytic performance of novel gamma alumina present a volcanic curve with the increase in steam treatment temperature. Under the optimal water vapor treatment temperature of 650 °C, the conversion of ethanol and selectivity of ethylene were both higher than 99%.

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“…[46][47][48] In addition, the Lewis and Brønsted acid sites should play an important role in the reaction. Topchieva et al 49 suggested that the dehydration of ethanol occurs essentially with the aid of Brønsted acid sites via the formation of ethoxide (C 2 H 5 O À ) surface species. However, according to Hussein et al, 50 the different mechanistic pathways for the dehydration of ethanol to diethyl ether and ethene depended largely on the surface hydroxylation.…”

Section: Catalytic Performancementioning

confidence: 99%

Novel catalyst PTMA-PILC: structural properties and catalytic performance for the dehydration of bioethanol to ethylene

Xie

et al. 2015

RSC Adv.

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81 Function of Surface Compounds in the Study of Catalytic Dehydration of Alcohols over Aluminum Oxide and Silica-Alumina Catalysts

Cited by 30 publications

References 0 publications

Continuous Gas-Phase Synthesis of 1-Ethyl Chloride from Ethyl Alcohol and Hydrochloric Acid Over Al₂O₃-Based Catalysts: The “Green” Route

Continuous Gas-Phase Synthesis of 1-Ethyl Chloride from Ethyl Alcohol and Hydrochloric Acid Over Al₂O₃-Based Catalysts: The “Green” Route

Ethanol Dehydration to Ethylene over High-Energy Facets Exposed Gamma Alumina

Novel catalyst PTMA-PILC: structural properties and catalytic performance for the dehydration of bioethanol to ethylene

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81 Function of Surface Compounds in the Study of Catalytic Dehydration of Alcohols over Aluminum Oxide and Silica-Alumina Catalysts

Cited by 30 publications

References 0 publications

Continuous Gas-Phase Synthesis of 1-Ethyl Chloride from Ethyl Alcohol and Hydrochloric Acid Over Al2O3-Based Catalysts: The “Green” Route

Continuous Gas-Phase Synthesis of 1-Ethyl Chloride from Ethyl Alcohol and Hydrochloric Acid Over Al2O3-Based Catalysts: The “Green” Route

Ethanol Dehydration to Ethylene over High-Energy Facets Exposed Gamma Alumina

Novel catalyst PTMA-PILC: structural properties and catalytic performance for the dehydration of bioethanol to ethylene

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Product

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Continuous Gas-Phase Synthesis of 1-Ethyl Chloride from Ethyl Alcohol and Hydrochloric Acid Over Al₂O₃-Based Catalysts: The “Green” Route

Continuous Gas-Phase Synthesis of 1-Ethyl Chloride from Ethyl Alcohol and Hydrochloric Acid Over Al₂O₃-Based Catalysts: The “Green” Route