91-16-7Relevant articles and documents
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Pschorr,Silberbach
, p. 2151 (1904)
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Dimethoxybenzene and preparation method thereof
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Paragraph 0043-0065, (2021/05/29)
The invention relates to the field of etherification of organic compounds, and discloses dimethoxybenzene and a preparation method thereof. The method comprises the following steps that 1, in the presence of a catalyst, catechol serves as a raw material, dimethyl carbonate serves as a methylation reagent, a methylation reaction is conducted, and imethoxybenzene is obtained, wherein the catalyst is 1, 8-diazabicyclo [5.4. 0] undec-7-ene; and 2) the reaction product obtained in the step 1) is distilled to recover the dimethyl carbonate, and then reduced pressure distillation is performed to obtain the dimethoxybenzene. According to the method, the green and environment-friendly methylation reagent dimethyl carbonate is adopted, no waste water or solid is generated, the yield is high, and the method is very suitable for industrial production and meets the green and environment-friendly process requirements.
Role of Catalyst Support's Physicochemical Properties on Catalytic Transfer Hydrogenation over Palladium Catalysts
Batalha, Nuno,Fraga, Gabriel,Hasan, M. D.,Konarova, Muxina,Laycock, Bronwyn,Pratt, Steven,Santos, Mirella S.
, p. 5191 - 5202 (2021/10/29)
Catalytic transfer hydrogenation (CTH) is a promising reaction for valorisation of bio-based feedstocks via hydrogenation without needing to use H2. Unlike standard hydrogenation, CTH occurs via dehydrogenation (DHD) of a hydrogen donor (H-donor) and hydrogenation (HYD) of a substrate. Therefore, the “ideal” CTH catalyst must balance the catalysis of both reactions to maximize the hydrogen transfer between H-donor and substrate with minimal H2 loss to gas (high atom efficiency). Additionally, the H-donor must be highly stable to prevent secondary reactions with the substrate. Herein we study the impact of the catalyst's properties on CTH of guaiacol using bicyclohexyl, a liquid organic hydrogen carrier, as a H-donor. The reaction was promoted by palladium dispersed on three typical support materials (γ-Al2O3, MgO, and SiO2). The performance of these catalysts in the conversion of bicyclohexyl and guaiacol was evaluated, allowing to estimate the H-transfer efficiency, as well as the potential for recycling the spent H-donor (bicyclohexyl). The apparent activation energies for DHD of bicyclohexyl and HYD of guaiacol revealed that slow DHD combined with fast HYD, as is the case with Pd/MgO, favours hydrogen transfer efficiency and selectivity towards hydrogenated products. In addition, an investigation of the DHD of bicyclohexyl and HYD of guaiacol independently showed that the affinity between the organic molecules and the support significantly impacts CTH. Indeed, Pd/SiO2 was highly active for both reactions individually and almost inactive for CTH. Consequently, these findings highlight the importance of the interaction between solvent-substrate-support in designing catalysts for transfer hydrogenation.