Mass Transfer Advantage of Hierarchical Zeolites Promotes Methanol Converting into para-Methyl Group in Toluene Methylation

2017 ◽  
Vol 56 (33) ◽  
pp. 9310-9321 ◽  
Author(s):  
Jian Zhou ◽  
Yangdong Wang ◽  
Wei Zou ◽  
Chuanming Wang ◽  
Liyuan Li ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Hierarchical Zeolites ◽  
Methyl Group ◽  
Toluene Methylation

Catalytic fast pyrolysis of biomass: superior selectivity of hierarchical zeolites to aromatics

2017 ◽  
Vol 19 (22) ◽  
pp. 5442-5459 ◽  
Author(s):  
L. Y. Jia ◽  
M. Raad ◽  
S. Hamieh ◽  
J. Toufaily ◽  
T. Hamieh ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Aromatic Hydrocarbons ◽  
Fast Pyrolysis ◽  
Biomass Pyrolysis ◽  
Hierarchical Zeolites ◽  
Catalytic Fast Pyrolysis ◽  
Pyrolysis Of Biomass ◽  
Zeolite Crystals

Mesopores are “highways” for mass transfer inside zeolite crystals and enhance the formation of mono-aromatic hydrocarbons from biomass pyrolysis.

scholarly journals Hierarchical Zeolites as Catalysts for Biodiesel Production from Waste Frying Oils to Overcome Mass Transfer Limitations

Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 4879
Author(s):  
Elyssa G. Fawaz ◽  
Darine A. Salam ◽  
Severinne S. Rigolet ◽  
T. Jean Daou
Keyword(s):  
Mass Transfer ◽  
Molecular Diffusion ◽  
Maximum Yield ◽  
Catalytic Performance ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
Catalyst Loading ◽  
Hierarchical Zeolites ◽  
Frying Oils ◽  
Waste Frying Oils

Hierarchical crystals with short diffusion path, conventional microcrystals and nanocrystals of ZSM-5 zeolites were used for biodiesel production from waste frying oils and were assessed for their catalytic activity in regard to their pore structure and acidic properties. Produced zeolites were characterized using XRD, nitrogen adsorption–desorption, SEM, TEM, X-ray fluorescence, and FTIR. Pore size effect on molecular diffusion limitation was assessed by Thiele modulus calculations and turnover frequencies (TOF) were used to discuss the correlation between acidic character and catalytic performance of the zeolites. Owing to the enhanced accessibility and mass transfer of triglycerides and free fatty acids to the elemental active zeolitic structure, the catalytic performance of nanosponge and nanosheet hierarchical zeolites was the highest. A maximum yield of 48.29% was reached for the transesterification of waste frying oils (WFOs) using HZSM-5 nanosheets at 12:1 methanol to WFOs molar ratio, 180 °C, 10 wt % catalyst loading, and 4 h reaction time. Although HZSM-5 nanosponges achieved high conversions, these more hydrophilic zeolites did not function according to their entire acidic strength in comparison to HZSM-5 nanosheets. NSh-HZSM5 catalytic performance was still high after 4 consecutive cycles as a result of the zeolite regeneration.

Recent progress in the direct synthesis of hierarchical zeolites: synthetic strategies and characterization methods

2017 ◽  
Vol 1 (11) ◽  
pp. 2195-2212 ◽  
Author(s):  
Zhaohui Liu ◽  
Yingjie Hua ◽  
Jianjian Wang ◽  
Xinglong Dong ◽  
Qiwei Tian ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Mesoporous Materials ◽  
Recent Progress ◽  
Molecular Diffusion ◽  
Direct Synthesis ◽  
Hierarchical Zeolites ◽  
Characterization Methods ◽  
Catalytic Activities

Hierarchically structured zeolites combine the merits of microporous zeolites and mesoporous materials to offer enhanced molecular diffusion and mass transfer without compromising the inherent catalytic activities and selectivity of zeolites.

Use of [13C-methyl]Tropinone to follow the fate of the methyl group during calystegine formation in root cultures of Solanum dulcamara (Solanaceae)

Planta Medica ◽  
2008 ◽  
Vol 74 (09) ◽  
Author(s):  
TA Bartholomeusz ◽  
R Molinié ◽  
A Roscher ◽  
AC Freydank ◽  
B Dräger ◽  
...  
Keyword(s):  
Root Cultures ◽  
Solanum Dulcamara ◽  
Methyl Group
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