Synthesis of bifunctional tin-based silica–carbon catalysts, Sn/KIT-1/C, with tunable acid sites for the catalytic transformation of glucose into 5-hydroxymethylfurfural

2022 ◽  
Vol 429 ◽  
pp. 132261
Author(s):  
Armin Rezayan ◽  
Ke Wang ◽  
Renfeng Nie ◽  
Tianliang Lu ◽  
Jianshe Wang ◽  
...  
2019 ◽  
Vol 5 (12) ◽  
pp. 12-19 ◽  
Author(s):  
V. Doluda ◽  
N. Lakina ◽  
R. Brovko

Decrease of traditional hydrocarbon feed stock stimulates a widespread interest in the development hydrocarbons synthesis from renewable or low-value sources. The catalytic transformation of methanol into hydrocarbons, along with the Fischer–Tropsch process, can be considered as a possible way to obtain synthetic hydrocarbons. At the same time, the activity and stability of the catalysts have a decisive influence on the efficiency of the whole process. Zeolites and zeotypes of various structures traditionally used as catalysts are characterized by low rates of hydrocarbon accumulation and a short period of functioning, which requires a change in their structural characteristics or the synthesis of new systems. The aim of this work is to obtain iron-modified H-ZSM-5 type zeolites in order to increase the rate of liquid hydrocarbons accumulation and increase the lifetime of the catalyst. To achieve this goal zeolite was modified with iron, the main physicochemical characteristics of the obtained catalysts were determined and the catalytic properties were screened. Modification of zeolites by iron was carried out by the ion exchange method, as a result samples with an iron content of 0.004 wt.% to 0.240 wt.% were synthesized. In this case the decrease in the micropores surface from 280 m2/g to 190 m2/g and decrease in the number of acid sites from 1.08 mmol/g to 0.72 mmol/g was noticed. Modification of zeolite with iron of concentration up to 0.008 wt. % contributed to an increase in transformation rate of dimethyl ether from 0.04 to 0.06 kg (DME)/(kg (Cat)h) and decreace to 0.03 kg (DME)/(kg (Cat) h) during further increasing of iron content, however process selectivity to liquid hydrocarbons increase from 30% to 54%. Modification of zeolite with iron contributes to a significant change in hydrocarbon composition. With an increase in the iron concentration from 0.004 wt.% to 0.017 wt.%, the increase in the concentration of propane, butane and aliphatic hydrocarbons with the number of carbon atoms of six or more was noticed along with a decrease in the concentration of aromatic compounds.


Carbon ◽  
2021 ◽  
Vol 175 ◽  
pp. 614
Author(s):  
Hirokazu Kobayashi ◽  
Atsushi Fukuoka

TANSO ◽  
2019 ◽  
Vol 2019 (290) ◽  
pp. 211-218
Author(s):  
Hirokazu Kobayashi ◽  
Atsushi Fukuoka

2021 ◽  
Vol 49 (9) ◽  
pp. 1326-1335
Author(s):  
Jia-bao YANG ◽  
Yu HUI ◽  
Yu-cai QIN ◽  
Xiao-tong ZHANG ◽  
Huan WANG ◽  
...  

Author(s):  
Clifford S. Rainey

The spatial distribution of V and Ni deposited within fluidized catalytic cracking (FCC) catalyst is studied because these metals contribute to catalyst deactivation. Y zeolite in FCC microspheres are high SiO2 aluminosilicates with molecular-sized channels that contain a mixture of lanthanoids. They must withstand high regeneration temperatures and retain acid sites needed for cracking of hydrocarbons, a process essential for efficient gasoline production. Zeolite in combination with V to form vanadates, or less diffusion in the channels due to coke formation, may deactivate catalyst. Other factors such as metal "skins", microsphere sintering, and attrition may also be involved. SEM of FCC fracture surfaces, AEM of Y zeolite, and electron microscopy of this work are developed to better understand and minimize catalyst deactivation.


2010 ◽  
Vol 31 (1) ◽  
pp. 72-77
Author(s):  
Xuanyan LIU ◽  
Dulin YIN ◽  
Huayuan ZHU ◽  
Gang SHEN
Keyword(s):  

1981 ◽  
Vol 46 (11) ◽  
pp. 2669-2675 ◽  
Author(s):  
Ivo Paseka

Hydrogenation of nitrogen oxide in acid solutions on Pt-C catalysts proceeds in dependence on experimental conditions either in purely diffusion region or in the diffusion and kinetically controlled region. The boundary between these two processes shifts to the higher ratio of NO to H2 partial pressures with increasing platinum content and decreasing intensity of agitation.


1996 ◽  
Vol 61 (8) ◽  
pp. 1115-1130 ◽  
Author(s):  
Jiří Čejka ◽  
Naděžda Žilková ◽  
Blanka Wichterlová

Kinetic study of toluene and benzene alkylation with isopropyl alcohol on alumo- and ferrisilicates of MFI structure has shown that the alkylation activity does not follow the acidity (both the number and strength of bridging OH groups) of these molecular sieves. The rate of the overall reaction is controlled by the desorption/transport rate of bulky, strongly adsorbed cymenes and cumene. A higher concentration of n-propyltoluenes compared to n-propylbenzene, both undesired reaction products, formed via a bimolecular isomerization of isopropyl aromate with benzene or toluene, was due to the higher reactivity of isopropyltoluene with toluene in comparison with that of cumene with benzene. It is concluded that ferrisilicates of MFI structure possessing low strength acid sites appear to be promising catalysts for achieving both a high isopropyl- and para-selectivity in toluene alkylation to p-cymene.


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