catalyst acidity
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ACS Catalysis ◽  
2022 ◽  
pp. 1520-1531
Author(s):  
Jingxiu Xie ◽  
Daniel S. Firth ◽  
Tomás Cordero-Lanzac ◽  
Alessia Airi ◽  
Chiara Negri ◽  
...  

Processes ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1815
Author(s):  
João Paulo da S. Q. Menezes ◽  
Gabriel M. Guimarães ◽  
Mônica A. P. da Silva ◽  
Mariana M. V. M. Souza

Hydrogen is mainly produced by steam reforming of natural gas, a nonrenewable resource. Alternative and renewable routes for hydrogen production play an important role in reducing dependence on oil and minimizing the emission of greenhouse gases. In this work, butanol, a model compound of bio-oil, was employed for hydrogen production by steam reforming. The reaction was evaluated for 30 h in a tubular quartz reactor at 500 °C, atmospheric pressure, GHSV of 500,000 h−1, and an aqueous solution feed of 10% v/v butanol. For this reaction, catalysts with 20 wt.% NiO were prepared by wet impregnation using three supports: γ-alumina and alumina modified with 10 wt.% of cerium and lanthanum oxides. Both promoters increased the reduction degree of the catalysts and decreased catalyst acidity, which is closely related to coke formation and deactivation. Ni/La2O3–Al2O3 presented a higher nickel dispersion (14.6%) which, combined with other properties, led to a higher stability, higher mean hydrogen yield (71%), and lower coke formation per mass (56%). On the other hand, the nonpromoted catalyst suffered a significant deactivation associated with coke formation favored by its highest acidity (3.1 µmol m−²).


Author(s):  
John Eleeza ◽  
Philip Boahene ◽  
Sundaramurthy Vedachalam ◽  
Ajay K. Dalai ◽  
John Adjaye

2021 ◽  
Author(s):  
Dimitra Makarouni ◽  
Christos Kordulis ◽  
Vassilis Dourtoglou

AbstractApplication of a novel “zeolite catalyst–solvent” system for the sustainable one-step synthesis of the terpenoid manoyl oxide, the potential precursor of forskolin and ambrox. Manoyl oxide high-yield and large-scale production over a zeolite catalyst has been infeasible so far, while this system results in 90% yields at 135 °C and atmospheric pressure. Substrate-controlled methodology is used to achieve selectivity. Solvent-driven catalysis is shown, as the activation energy barrier decreases in the presence of appropriate solvents, being 62.7 and 93.46 kJmol−1 for a glyme-type solvent and dodecane, respectively. Finally, catalyst acidity is key parameter for the process. Graphic Abstract


2021 ◽  
Vol 35 (4) ◽  
pp. 3295-3306
Author(s):  
Hailing Sun ◽  
Liyuan Cao ◽  
Yuhao Zhang ◽  
Liang Zhao ◽  
Jinsen Gao ◽  
...  

2020 ◽  
Vol 7 (4) ◽  
pp. 297-311
Author(s):  
Toyese Oyegoke ◽  
◽  
Fadimatu N. Dabai ◽  
Adamu Uzairu ◽  
Baba El-Yakubu Jibril ◽  
...  

2020 ◽  
Vol 5 (3) ◽  
pp. 410-420 ◽  
Author(s):  
Lisna Efiyanti ◽  
Dian Anggraini Indrawan ◽  
Zulhan Arif ◽  
Devandri Hutapea ◽  
Ane Dwi Septina

Biomass, such as wood waste, is one of the resources that can be potentially converted into a carbon product for catalyst applications. In this study, the sulfonated carbon was obtained through the pyrolysis method for wood waste at the temperature of 350°C, which was later sulfonated through the use of  H2SO4 (8N) on the reflux for 4 h. The sulfonated carbon was then analyzed and characterized including its water content, ash content, volatile matter, fixed carbon, iodine adsorption as well as the H+ (acidity) capacity using ammonia adsorptions and functional groups and the Fourier Transform Infra-Red (FTIR) instrument. The catalyst application was carried out during the kempili pulp hydrolysis process using a microwave with the ratio of catalyst to a pulp of 1:1 (5g:5g), with the power conditions of 300, 400, and 600 watt for 3, 5, and 7 min. The results showed that the sulfonated carbon catalyst had water content, volatile matter, ash content, fixed carbon, iodine adsorption as well as the catalyst acidity as much as 3.48%; 11.70%; 4.21%; 84.62%; 690.88 mg/g; and 6.45 mmol/g, respectively with the highest glucose content of 160.83 ppm. The carbon-based catalyst is expected as an alternative catalyst, can be further developed for hydrolysis reactions, and can serve as a green technology product in the future.


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