scholarly journals Nanostructured zeolite with brain-coral morphology and tailored acidity: a self-organized hierarchical porous material with MFI topology

CrystEngComm ◽  
2020 ◽  
Vol 22 (38) ◽  
pp. 6275-6286
Author(s):  
Esun Selvam ◽  
Rajesh K. Parsapur ◽  
Carlos E. Hernandez-Tamargo ◽  
Nora H. de Leeuw ◽  
Parasuraman Selvam
Keyword(s):  
Solid Acid ◽  
Solid Acid Catalyst ◽  
High Surface ◽  
High Surface Area ◽  
Acid Catalyst ◽  
Acid Sites ◽  
Diffusion Resistance ◽  
Self Organized ◽  
Hierarchical Porous ◽  
Coral Morphology

Nano-zeolite with brain-coral morphology formed by self-organization of ultra-small nanospheres, exhibits micro/meso porosity with high surface area, distributed acid sites, and reduced diffusion resistance making it a promising solid acid catalyst.

scholarly journals Mesoporous Porphyrin-Silica Nanocomposite as Solid Acid Catalyst for High Yield Synthesis of HMF in Water

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2519
Author(s):  
Arindam Modak ◽  
Akshay R. Mankar ◽  
Kamal Kishore Pant ◽  
Asim Bhaumik
Keyword(s):  
Sulfonic Acid ◽  
Solid Acid ◽  
Solid Acid Catalyst ◽  
High Surface ◽  
High Surface Area ◽  
Acid Catalyst ◽  
Acid Sites ◽  
Environmental Research ◽  
Organic Polymer ◽  
High Yield

Solid acid catalysts occupy a special class in heterogeneous catalysis for their efficiency in eco-friendly conversion of biomass into demanding chemicals. We synthesized porphyrin containing porous organic polymers (PorPOPs) using colloidal silica as a support. Post-modification with chlorosulfonic acid enabled sulfonic acid functionalization, and the resulting material (PorPOPS) showed excellent activity and durability for the conversion of fructose to 5-hydroxymethyl furfural (HMF) in green solvent water. PorPOPS composite was characterized by N2 sorption, FTIR, TGA, CHNS, FESEM, TEM and XPS techniques, justifying the successful synthesis of organic networks and the grafting of sulfonic acid sites (5 wt%). Furthermore, a high surface area (260 m2/g) and the presence of distinct mesopores of ~15 nm were distinctly different from the porphyrin containing sulfonated porous organic polymer (FePOP-1S). Surprisingly the hybrid PorPOPS showed an excellent yield of HMF (85%) and high selectivity (>90%) in water as compared to microporous pristine-FePOP-1S (yield of HMF = 35%). This research demonstrates the requirement of organic modification on silica surfaces to tailor the activity and selectivity of the catalysts. We foresee that this research may inspire further applications of biomass conversion in water in future environmental research.

scholarly journals Mesoporous Crystalline Niobium Oxide with a High Surface Area: A Solid Acid Catalyst for Alkyne Hydration

2020 ◽  
Vol 12 (42) ◽  
pp. 47389-47396 ◽  
Author(s):  
Dinithi Rathnayake ◽  
Inosh Perera ◽  
Alireza Shirazi-Amin ◽  
Peter Kerns ◽  
Shanka Dissanayake ◽  
...  
Keyword(s):  
Surface Area ◽  
Niobium Oxide ◽  
Solid Acid ◽  
Solid Acid Catalyst ◽  
High Surface ◽  
High Surface Area ◽  
Acid Catalyst

scholarly journals Sulfonated Graphitic Carbon Nitride (Sg-C3N4): A Highly Efficient Heterogeneous Organo-Catalyst for Condensation Reactions

Proceedings ◽  
2019 ◽  
Vol 41 (1) ◽  
pp. 14
Author(s):  
Hossein Ghafuri ◽  
Peyman Hanifehnejad ◽  
Zeynab Rezazadeh ◽  
Afsaneh Rashidizadeh
Keyword(s):  
Chemical Stability ◽  
Carbon Nitride ◽  
Solid Acid ◽  
Solid Acid Catalyst ◽  
High Surface ◽  
High Surface Area ◽  
Acid Catalyst ◽  
Graphitic Carbon ◽  
Graphitic Carbon Nitride ◽  
High Catalytic Activity

Currently, constructing solid acid catalysts with well-defined structures, environmentally benign, with high catalytic activity, easy separation, and high chemical stability is the most important area of industrial and environmental concern. Over the past few decades, porous conjugated polymers have been employed as stable catalyst supports for various organic transformations. Among these materials, graphitic carbon nitride (g-C3N4) has been widely studied in the field of photocatalysis and heterogeneous catalysis, due to its high surface area and great physical and chemical stability. Herein, we report the synthesis of sulfonated graphitic carbon nitride (Sg-C3N4) as an efficient solid acid catalyst for the preparation of various biologically nitrogen-containing heterocyclic compounds under mild reaction conditions.

scholarly journals Hierarchical HZSM-5 for Catalytic Cracking of Oleic Acid to Biofuels

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 747
Author(s):  
Mahashanon Arumugam ◽  
Chee Keong Goh ◽  
Zulkarnain Zainal ◽  
Sugeng Triwahyono ◽  
Adam F. Lee ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Solid Acid ◽  
High Surface ◽  
High Surface Area ◽  
Acid Catalyst ◽  
Hierarchical Network ◽  
Waste Oil ◽  
Acid Catalyzed ◽  
Zeolite Seeds ◽  
20 Nm

Solid acid catalyzed cracking of waste oil-derived fatty acids is an attractive route to hydrocarbon fuels. HZSM-5 is an effective acid catalyst for fatty acid cracking; however, its microporous nature is susceptible to rapid deactivation by coking. We report the synthesis and application of hierarchical HZSM-5 (h-HZSM-5) in which silanization of pre-crystallized zeolite seeds is employed to introduce mesoporosity during the aggregation of growing crystallites. The resulting h-HZSM-5 comprises a disordered array of fused 10–20 nm crystallites and mesopores with a mean diameter of 13 nm, which maintain the high surface area and acidity of a conventional HZSM-5. Mesopores increase the yield of diesel range hydrocarbons obtained from oleic acid deoxygenation from ~20% to 65%, attributed to improved acid site accessibility within the hierarchical network.

Synthesis of 2,3-dihydroquinazolin-4(1H)-ones catalyzed by Perchlorated Zirconia (HClO4/ZrO2) nanoparticles as a novel solid acid catalyst

2018 ◽  
Vol 2 (2) ◽  
Author(s):  
Seyed Yousef Mosavian
Keyword(s):  
Solid Acid ◽  
Condensation Reaction ◽  
Solid Acid Catalyst ◽  
Sol Gel ◽  
Acid Catalyst ◽  
Catalytic Performance ◽  
Acid Sites ◽  
Zro2 Nanoparticles ◽  
Calcination Temperatures ◽  
Aldehydes And Ketones

Zirconia was synthesized in nanosize by sol-gel method and perchlorated zirconia (HClO4/ZrO2) with various calcination temperatures were prepared and characterized by XRD, FTIR and SEM techniques. The catalyst acidity characters, including the acidicstrength and the total number of acid sites were determined by potentiometric titration. The catalytic performance experiments show that the HClO4/ZrO2 with calcination temperature of 300 °C has the best catalytic activity. 2,3-Dihydroquinazolin-4(1H)-ones wereprepared in good to excellent yields via condensation reaction of oaminobenzamide and various types of aldehydes and ketones in the presence of HClO4/ZrO2 nanoparticles as an efficient solid acid catalyst. The catalyst is reusable with moderate loss in activity.

scholarly journals Preparation of a novel solid acid catalyst with Lewis and Br{\o}nsted acid sites and its application in acetalization

2014 ◽  
Vol 38 ◽  
pp. 157-163 ◽  
Author(s):  
Yijun DU ◽  
Linjun SHAO ◽  
Lingyan LUO ◽  
Si SHI ◽  
Chenze QI
Keyword(s):  
Solid Acid ◽  
Solid Acid Catalyst ◽  
Acid Catalyst ◽  
Acid Sites

scholarly journals Acid Properties of GO and Reduced GO as Determined by Microcalorimetry, FTIR, and Kinetics of Cellulose Hydrolysis-Hydrogenolysis

Catalysts ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1393
Author(s):  
Van Chuc Nguyen ◽  
Sarah Kheireddine ◽  
Amar Dandach ◽  
Marion Eternot ◽  
Thi Thu Ha Vu ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Solid Acid ◽  
Solid Acid Catalyst ◽  
High Mobility ◽  
Acid Catalyst ◽  
Strong Acid ◽  
Cellulose Hydrolysis ◽  
Acid Sites ◽  
Pyridine Adsorption ◽  
Nh3 Adsorption

Graphene oxide addresses increasing interests as a solid acid catalyst working in water for carbohydrate conversion. If there is a general agreement to correlate its unique catalytic performances to its ability to adsorb sugars, the origin of its acidity remains controversial. In this article, we study the acid strength of graphene oxide (GO) prepared by modified Hummers method and that of reduced GO by calorimetry of NH3 adsorption and by FTIR of pyridine adsorption. Very strong acid sites are detected on GO by calorimetry, while reduced graphene oxide (reGO) is not very acidic. The FTIR of pyridine adsorption shows the prevailing presence of Br∅nsted acid sites and a unique feature, the presence of pyridine coordinated by hydrogen bonds. This exceptionally strong Br∅nsted acidity is tentatively explained by the presence of graphene domains decorated by hydroxyl, carboxylic, or sulfonated groups within the GO sheet, resulting in a high mobility of the negative charges which makes the proton free and explains its strong acidity. Accordingly, only GO is active and selective for native cellulose hydrolysis, leading to 27% yield in glucose. Finally, we show that sugar alcohols cannot be formed directly from cellulose using GO combined with Pt/re-GO under hydrogen, explained by the reduction of oxygenated functions of GO. The instability of the functional groups of GO in a reducing atmosphere is the weak point of this peculiar solid acid.

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