48 results on '"Baithy, Mallesham"'
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2. Catalytic enhancement of biomass-derived furfural via Knoevenagel condensation using Ru/Al2O3-ZrO2 catalyst for sustainable synthesis of value-added chemicals
- Author
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Dosarapu, Vijaykumar, Siddaramagoud, Bandalla, Ramesh, Karu, Mavurapu, Satyanarayana, Baithy, Mallesham, Varkolu, Mohan, Ravinder, Vadde, and Vasam, Chandrasekhar
- Published
- 2024
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3. Design of visible light-assisted Fenton-like Ni-Fe oxide nanocomposites for photodegradation of rhodamine-B
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BAITHY, MALLESHAM, GOGOI, ANIRUDDHA, BORGOHAIN, CHANDAN, NAGARE, AKASH, BHITRE, SANDESH, GOGOI, PARIKSHIT, and NAVGIRE, MADHUKAR
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- 2023
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4. Highly efficient solvent-free oxidation of cyclohexanol to cyclohexanone over nanocrystalline CaO–MgO binary metal-oxide catalysts
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Bandalla, Siddaramagoud, Dosarapu, Vijaykumar, Bathula, Ganesh Babu, Ravula, Madhu, Yadagiri, Jyothi, Gogoi, Parikshit, Baithy, Mallesham, Jonnalagadda, Sreekantha B, and Vasam, Chandra Shekar
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- 2022
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5. Boosting catalytic efficiency of nanostructured CuO-supported doped-CeO2 in oxidative coupling of benzyl amines to N-benzylidenebenzyl amines and benzimidazoles: impact of acidic and defect sites.
- Author
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Sakinala, Sailatha, Kothoori, Naga Pranava Sree, Jeedi, Suman, Varkolu, Mohan, and Baithy, Mallesham
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OXYGEN vacancy ,SURFACE analysis ,CATALYTIC activity ,COPPER ,BENZYLAMINE - Abstract
This study presents the rational synthesis of Cu-supported doped-CeO
2 catalysts designed for the oxidation of benzylamine, both in the absence and presence of 1,2-diaminobenzene. The catalysts were prepared using a two-step method and characterized by various techniques, including XRD, Raman spectroscopy, BET surface area analysis, NH3 -TPD, pyridine-FTIR, H2 -TPR, XPS, SEM, and TEM. Raman and XPS analyses confirmed the presence of oxygen vacancy sites, with CuO/CeO2 -ZrO2 displaying the highest concentration of these sites. H2 -TPR revealed strong metal-support interactions, while NH3 -TPD indicated that CuO/CeO2 -ZrO2 possessed the greatest number of acidic sites. The pyridine-FTIR results indicates both the acidic sites present on the catalyst surface. The Cu/CeZr sample exhibits the lowest Iu /// /ITotal ratio (0.0567) compared to the Cu/Ce (0.0843) and Cu/CeSi (0.0672) samples, indicating a higher number of Ce3+ species or a greater number of oxygen defect sites in the sample. The catalyst demonstrated excellent performance in converting benzylamine to imines and was also highly effective in the synthesis of benzimidazole from benzylamine and 1,2-diaminobenzene, broadening its application potential. The superior catalytic activity is attributed to the abundant oxygen vacancies, redox properties, strong metal-support interactions, and acidic sites. Furthermore, the CuO/CeO2 -ZrO2 catalyst maintained its efficiency over five consecutive cycles, exhibiting robustness, high functional group tolerance, and reduced reaction times, making it a promising system for diverse catalytic applications. [ABSTRACT FROM AUTHOR]- Published
- 2025
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6. Structure–Activity Relationships of WOx-Promoted TiO2–ZrO2 Solid Acid Catalyst for Acetalization and Ketalization of Glycerol towards Biofuel Additives
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Baithy, Mallesham, Mukherjee, Deboshree, Rangaswamy, Agolu, and Reddy, Benjaram M.
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- 2022
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7. Efficient Nanocomposite Catalysts for Sustainable Production of Biofuels and Chemicals from Furanics
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Baithy, Mallesham, Raikwar, Deepak, Shee, Debaprasad, Pant, K. K., editor, Gupta, Sanjay Kumar, editor, and Ahmad, Ejaz, editor
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- 2021
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8. Transformation of Agriculture Waste Biomass to Sustainable and Slow Release Fertilizers: Waste to Wealth.
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Galipalli, Ramu, Baithy, Mallesham, and Vishnu, Nandimalla
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SUSTAINABLE agriculture , *SOIL fertility , *ECOLOGICAL impact , *CROP yields , *LIGNOCELLULOSE - Abstract
Novel lignocellulosic biomass‐based fertilizers are developed to enhance crop yields while minimizing ecological impacts. These fertilizers, enriched with macro and micronutrients, feature slow‐release properties, reducing nutrient loss compared to conventional fertilizers. The study emphasizes their potential in sustainable agriculture, offering a viable alternative for soil fertility and crop yield. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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9. Rational Design and Investigation of Nonlinear Optical Response Properties of Pyrrolopyrrole Aza-BODIPY-Based Novel Push-Pull Chromophores
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Kothoori, Naga Pranava Sree, primary, Sivasakthi, Pandiyan, additional, Baithy, Mallesham, additional, Misra, Ramprasad, additional, and Samanta, Pralok, additional
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- 2024
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10. Sol-Gel Assisted β-Cyclodextrin Coated MoO3-Fe3O4 Nanocomposite for Photodegradation of Methylene Blue Dye
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Nagare, Akash, primary, Dhadage, Amol, additional, Baithy, Mallesham, additional, BHUYAN, Priyanga, additional, Gogoi, Parikshit, additional, Athare, Anil, additional, and Navgire, Madhukar, additional
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- 2024
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11. Nanostructured Nickel/Silica Catalysts for Continuous Flow Conversion of Levulinic Acid to γ‑Valerolactone
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Baithy Mallesham, Putla Sudarsanam, Bellala Venkata Shiva Reddy, Bolla Govinda Rao, and Benjaram M. Reddy
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Chemistry ,QD1-999 - Published
- 2018
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12. Supported Metal Nanoparticles as Heterogeneous Catalysts for Transformation of Biomass-Derived Platform Chemicals
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Baithy, Mallesham, primary and Shee, Debaprasad, additional
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- 2020
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13. Sol-gel assisted β-cyclodextrin coated MoO3-Fe2O3 nanocomposite for photodegradation of methylene blue dye.
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Nagare, Akash, Dhadage, Amol, Baithy, Mallesham, Bhuyan, Priyanga Manjuri, Gogoi, Parikshit, Athare, Anil, and Navgire, Madhukar
- Abstract
In this work, a series of β-Cyclodextrin coated MoO
3 -Fe2 O3 nanocomposites were synthesized by the sol-gel technique for degradation of methylene blue in presence of light from aqueous solutions. The prepared materials were analyzed by using powder XRD, FT-IR, UV-DRS, FE-SEM, HR-TEM, RAMAN, BET, and XPS techniques. The X-ray diffraction spectra of β-CD coated MoO3 -doped Fe2 O3 confirms the orthorhombic phase of the Fe2 (MoO4 )3 nanocomposite. The allowed indirect transition optical energy band gap of nanocomposites lies between 2.67 and 1.71 eV. The FE-SEM study revealed that nanoflakes change in the morphology of the nanocomposites sample, and it gives an estimated size below 30 nm. The 10 mgL−1 methylene dye degrades efficiently around 91.62% within 1 h. with reaction condition of 15 mg 5% β-Cyclodextrin coated MoO3 -Fe2 O3 catalyst, 6 pH, 10 mM concentration of H2 O2 , at room temperature under sunlight. The pure MoO3 and Fe2 O3 gives 38.21% and 77.10%, shows less activity compare with 5βMF catalyst. This study provides newer catalytic system which shows better photocatalytic degradation of dyes from industrial waste water. Highlight: The β-Cyclodextrin coated MoO3 -Fe2 O3 nanocomposites was successfully prepared by using the cost effective sol-gel technique. The efficiency of nanocomposites was improve using β-Cyclodextrin which gives more active sites and fast charge carrier separation. The reaction successfully carried outstanding efficiency of 5βMF for the degradation of methylene blue. Its result gives 91.62% degradation of MB in short reaction time as compare to the other nanocomposites samples. It concludes that, efficiency of photocatalyst increases with the loading of MoO3 on Fe2 O3 . This 5βMF catalyst shows better activities within short duration, use of less quantity of catalyst and in works in visible light region. [ABSTRACT FROM AUTHOR]- Published
- 2024
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14. Rational design and investigation of nonlinear optical response properties of pyrrolopyrrole azaBODIPY-based novel push–pull chromophores.
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Sree Kothoori, Naga Pranava, Sivasakthi, Pandiyan, Baithy, Mallesham, Misra, Ramprasad, and Samanta, Pralok K.
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- 2024
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15. Development of Molybdenum oxide Promoted CeO2−SiO2 Mixed‐oxide Catalyst for Efficient Catalytic Oxidation of Benzylamine to N‐Benzylidenebenzylamine.
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Ravula, Madhu, Dosarapu, Vijaykumar, Bandalla, Siddaramagoud, Mavurapu, Satyanarayana, Varkolu, Mohan, Rajeevan, Aswathi, Baithy, Mallesham, Jonnalagadda, Sreekantha B., and Sekhar Vasam, Chandra
- Subjects
MOLYBDENUM oxides ,OXIDATIVE coupling ,CATALYTIC oxidation ,BENZYLAMINE ,CATALYSTS ,MOLYBDENUM ,CERIUM oxides ,RAMAN spectroscopy - Abstract
This study explores a rational synthesis of a molybdenum‐promoted Ce−Si mixed oxide catalyst (MoO3/CeO2−SiO2) to regulate synergies between MoO3 and SiO2 dopant on CeO2, achieving high selectivity in solvent‐free catalytic oxidative coupling of amines to imines using molecular O2 as the oxidant. Comparative efficiency tests were conducted with bare CeO2, CeO2−SiO2, and MoO3/CeO2 catalysts. Characterization techniques, including XRD, Raman spectroscopy, N2‐adsorption‐desorption analysis, FTIR, NH3−TPD, TEM, and XPS, were employed to assess textural properties, acidic features, promoter and dopant dispersion in CeO2 lattice, and oxygen defects. Mo/Ce−Si catalyst exhibited superior acidic sites and a higher concentration of Ce3+ ions (Iu/ITotal), indicating increased oxygen vacancies. This catalyst demonstrated exceptional performance in the oxidative coupling of benzylamine, providing higher conversion and selectivity to the corresponding imine. Remarkably, the Mo/Ce−Si catalyst maintained consistent performance over five recycling runs. The catalyst also proved effective for the selective oxidative coupling of various amine substrates with diverse steric and electronic properties. Experimental results confirmed a plausible reaction mechanism within the concise catalyst design. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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16. The role of WOx and dopants (ZrO2 and SiO2) on CeO2-based nanostructure catalysts in the selective oxidation of benzyl alcohol to benzaldehyde under ambient conditions
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Bathula, Ganeshbabu, primary, Rana, Surjyakanta, additional, Bandalla, Siddaramagoud, additional, Dosarapu, Vijaykumar, additional, Mavurapu, Satyanarayana, additional, Rajeevan V. V., Aswathi, additional, Sharma, Bhaskar, additional, Jonnalagadda, Sreekantha B., additional, Baithy, Mallesham, additional, and Vasam, Chandra Shekar, additional
- Published
- 2023
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17. Development of Highly Efficient Heterogeneous Fe3O4‐Biochar Nanocomposite as Fenton‐like Catalysts for Degradation of Fast Green.
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Gogoi, Aniruddha, Baithy, Mallesham, Navgire, Madhukar, Gogoi, Nirmali, Borgohain, Chandan, Kamal Senapati, Kula, Sarmah, Jayanta K., Kim, Jongwon, and Gogoi, Parikshit
- Subjects
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HETEROGENEOUS catalysts , *FERRIC oxide , *ORGANIC dyes , *IRON oxides , *NANOCOMPOSITE materials , *WATER shortages , *CATALYSTS - Abstract
Iron oxide and its carbon‐containing biochar have shown efficiencies in Fenton oxidation reactions in recent years. Though magnetic biochar composites have been reported, developing facile, environment‐friendly methods with appropriate activity remains challenging. Removing dye traces from aqueous solutions is a prime concern under water scarcity issues at different levels. We developed a catalyst of biochar with magnetite for dye remediation. Magnetite is homogeneously loaded on biochar surfaces to form Fe3O4‐biochar to efficiently activate H2O2 to achieve hydroxyl radicals. This catalyst degrades Fast green dye efficiently around 89.3 % within 60 min with the optimum reaction conditions of 15 mM Fast Green dye, pH=4, 30 mg of Fe3O4‐biochar and 25 mM of H2O2. The composite shows around 41 % increase in the degradation rate after incorporating the Fe3O4 on biochar. The prepared Fe3O4‐biochar composite can be easily recycled without significant activity loss for five successive degradation reactions. The reported study provided a direction to prepare newer Fenton catalysts from sustainable sources for the degradation of organic dyes in water and overcame individual limitations of Fe3O4 and biochar. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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18. The role of WOx and dopants (ZrO2 and SiO2) on CeO2-based nanostructure catalysts in the selective oxidation of benzyl alcohol to benzaldehyde under ambient conditions.
- Author
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Bathula, Ganeshbabu, Rana, Surjyakanta, Bandalla, Siddaramagoud, Dosarapu, Vijaykumar, Mavurapu, Satyanarayana, Rajeevan V. V., Aswathi, Sharma, Bhaskar, Jonnalagadda, Sreekantha B., Baithy, Mallesham, and Vasam, Chandra Shekar
- Published
- 2023
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19. Insights into structure-activity relationships in efficient silica-supported Ni catalysts for selective hydrogenation of levulinic acid.
- Author
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Dosarapu, Vijaykumar, Bandalla, Siddaramagoud, Ravula, Madhu, Bathula, Ganesh Babu, Mavurapu, Satyanarayana, Shee, Debaprasad, Varkolu, Mohan, Baithy, Mallesham, and Vasam, Chandra Sekhar
- Published
- 2023
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20. Solvent-Free Production of Glycerol Carbonate from Bioglycerol with Urea Over Nanostructured Promoted SnO2 Catalysts
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Agolu Rangaswamy, Baithy Mallesham, Benjaram M. Reddy, Tumula Venkateshwar Rao, and Bolla Govinda Rao
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inorganic chemicals ,010405 organic chemistry ,General Chemistry ,010402 general chemistry ,01 natural sciences ,Catalysis ,0104 chemical sciences ,chemistry.chemical_compound ,Adsorption ,chemistry ,Chemical engineering ,Specific surface area ,Glycerol ,Urea ,Carbonate ,Carbonylation ,BET theory - Abstract
In this study nanostructured MoO3 and WO3 promoted SnO2 solid acid catalysts were explored for the production of glycerol carbonate via carbonylation of bioglycerol with urea. The investigated reference SnO2 and promoted catalysts were synthesized by fusion and wet-impregnation methods, respectively. The physicochemical properties of the prepared catalysts were thoroughly analyzed by XRD, Raman, BET surface area, TEM, FTIR, pyridine adsorbed FTIR, NH3-TPD, and XPS techniques. It was found from the characterization studies that integration of SnO2 with MoO3 and WO3 promoters leads to remarkable structural, textural, and acidic properties. Especially, a high quantity of acidic sites were observed over the MoO3/SnO2 catalyst (~ 81.45 μmol g−1) followed by WO3/SnO2 (61.81 μmol g−1) and pure SnO2 (46.47 μmol g−1), which played a key role in the carbonylation of bioglycerol with urea. The BET specific surface area and oxygen vacancies of SnO2 were significantly enhanced after the addition of MoO3 and WO3 promoters. TEM images revealed the formation of nanosized particles with a diameter of around 5–25 nm for the synthesized catalysts. The MoO3/SnO2 catalyst exhibited a high conversion and selectivity towards glycerol carbonate in comparison to other catalysts. The observed better performance is attributed to unique properties of MoO3/SnO2 catalyst including smaller crystallite size, high specific surface area, abundant oxygen vacancies, and more number of acidic sites. This catalyst also exhibited remarkable stability with no significant loss of activity in the recycling experiments. Nanostructured MoO3/SnO2 solid acid catalyst exhibited an excellent catalytic activity and a high selectivity to glycerol carbonate in the carbonylation of bioglycerol with urea under solvent-free and mild conditions.
- Published
- 2020
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21. Catalytic conversion of acrolein and acrylic acid drop-ins for added-value chemicals
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Baithy Mallesham, Hu Li, Putla Sudarsanam, and P. Suresh Babu
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chemistry.chemical_compound ,Chemistry ,Drop (liquid) ,Acrolein ,Added value ,Nuclear chemistry ,Catalysis ,Acrylic acid - Published
- 2022
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22. List of contributors
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Nidhi Adlakha, Jeyashelly Andas, Jimmy Nelson Appaturi, P. Suresh Babu, Jingsong Cheng, Taoli Deng, Leena Devendra, Siva Sankar Enumula, Mini Fernandez, Murali Dhar Gudimella, M. Ali Haider, K.V. Haseena, Jinguang Hu, Seetha Rama Rao Kamaraju, M.A. Khan, Md. Golam Kibria, Pawan Kumar, R. Jeevan Kumar, Can Li, Hu Li, Xiaofang Liu, Xiaoxiang Luo, Peihua Ma, Baithy Mallesham, Veerabhadraswamy Mruthyunjaya, Atul Narang, U. Naresh, Ashok Pandey, Binod Parameswaran, Veerapandian Ponnuchamy, Sindhu Raveendran, D. Sharada, K. Venkata Shiva, Putla Sudarsanam, Shouni Niveditha Tenali, Venkateswara Rao Tumula, Narisetty Vivek, Hongguo Wu, Wenfeng Wu, Qiuyun Zhang, and Yutao Zhang
- Published
- 2022
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23. Supported MoOx and WOx Solid Acids for Biomass Valorization: Interplay of Coordination Chemistry, Acidity, and Catalysis
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Nittan Singh, Putla Sudarsanam, Benjaram M. Reddy, Baithy Mallesham, Bert F. Sels, Pavan Narayan Kalbande, and Navneet Gupta
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TRANSITION-METAL OXIDES ,Biomass ,biomass valorization ,Catalysis ,tungsten oxide ,TUNGSTEN-OXIDE ,Coordination complex ,NMR CHEMICAL-SHIFTS ,molybdenum oxide ,SELECTIVE HYDROGENOLYSIS ,BIO-ADDITIVE FUELS ,acidity ,GAS-PHASE DEHYDRATION ,BIODIESEL PRODUCTION ,chemistry.chemical_classification ,Science & Technology ,catalysis ,Chemistry, Physical ,FREE FATTY-ACIDS ,General Chemistry ,MOLYBDENUM OXIDE CATALYSTS ,ONE-POT SYNTHESIS ,Chemistry ,Chemical engineering ,chemistry ,Physical Sciences ,coordination chemistry - Abstract
ispartof: Acs Catalysis vol:11 issue:21 pages:13603-13648 status: published
- Published
- 2021
24. Structure–Activity Relationships of WOx-Promoted TiO2–ZrO2 Solid Acid Catalyst for Acetalization and Ketalization of Glycerol towards Biofuel Additives
- Author
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Baithy, Mallesham, primary, Mukherjee, Deboshree, additional, Rangaswamy, Agolu, additional, and Reddy, Benjaram M., additional
- Published
- 2021
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25. Structure–Activity Relationships of WOx-Promoted TiO2–ZrO2 Solid Acid Catalyst for Acetalization and Ketalization of Glycerol towards Biofuel Additives.
- Author
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Baithy, Mallesham, Mukherjee, Deboshree, Rangaswamy, Agolu, and Reddy, Benjaram M.
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ACID catalysts ,STRUCTURE-activity relationships ,BIOMASS energy ,GLYCERIN ,CARBONYL compounds ,CATALYTIC activity - Abstract
WO
x -promoted TiO2 –ZrO2 solid acid catalyst was prepared and applied in the catalytic acetalization and ketalization of glycerol with carbonyl compounds to produce biofuel additives. The presence of WOx promoter and TiO2 remarkably improved the catalytic activity of ZrO2 . Approximately, 100% glycerol conversion was evidenced with non-bulky aliphatic aldehydes and ketones like, propanol and cyclohexanone. The physical characterization of WOx -promoted TiO2 –ZrO2, revealed a higher formation of tetragonal crystalline phase of ZrO2 , over monoclinic. The total surface acidity and the ratio of Brønsted to Lewis acidic site concentrations were determined by NH3 -TPD and pyridine-chemisorbed FTIR spectroscopy, respectively. A considerably higher concentration of Lewis acidic sites, ~ 213.29 μmol/gm, was evidenced on the WOx -promoted TiO2 –ZrO2 catalyst surface. Catalytic activity study revealed a direct correlation between the surface Lewis acidic site concentration and the activity of catalyst. This significant observation indicated the key role of Lewis acidic sites in this catalytic process. The WOx -promoted TiO2 –ZrO2 catalyst was also considerably stable and showed good performance in the acetalization/ketalization of glycerol with other substituted carbonyl compounds. The WOx -promoted TiO2 –ZrO2 solid acid catalyst exhibits superior catalytic performance for acetalization and ketalization of glycerol with carbonyl compounds to produce biofuel additives. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
26. The role of catalysis in green synthesis of chemicals for sustainable future
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Deepak Raikwar, Debaprasad Shee, and Baithy Mallesham
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Green chemistry ,Reaction mechanism ,Chemistry ,Hazardous waste ,Reagent ,Sustainable design ,Biochemical engineering ,Solid material ,Heterogeneous catalysis ,Catalysis - Abstract
This chapter is an endeavor to provide the valuable information on the role of heterogeneous catalysis in the green synthesis of chemicals for sustainable future. Heterogeneous catalysis plays a key role in the development of technology for the production of green chemicals from biomass-derived platform chemicals under environmentally benign processes. Thus, there is an increasing requirement for more environmentally and ecofriendly technologies for various industries. This situation tendency concerning about what is known as “Green Chemistry” or “Sustainable Technology” fundamentals a model shifts from traditional concepts to the new technologies that reduces waste at source and avoids the use of toxic and hazardous materials. In catalyzed reactions, the reaction requires less activation energy for synthesis of chemicals and higher efficiency was found in the generation of fewer undesired compounds such as products, co-products, and other waste substances. Designing of catalysts could be environmentally safe and different types of solid catalysts are presently applied in the chemical industries. The main advantages of heterogeneous catalysts in the green synthesis of chemicals that can be recovered and recycled to perform the reaction in preference to the additional reagents used by the initial process at each step. As well, solid materials are the most versatile features of heterogeneous catalysts and can greatly understanding the specific active sites, reaction mechanisms, reaction pathways, and the selectivity toward desirable chemicals. Specifically, catalysts made by molecular design and played a significant role in the development of environmentally ecofriendly processes. The various roles of heterogeneous catalysis in the green synthesis of chemicals such as HMF, FDCA, and LA from biomass-derived molecules are discussed considering properties of catalysts and reaction parameters. The effect of catalysts properties on yield and reaction mechanism for formation of HMF, FDCA, and LA are elucidated based on literature information
- Published
- 2020
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27. Contributors
- Author
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Burri Abhishek, Hari Babu Bathula, Vishal Chauhan, Venkata Pramod Chodimella, Vasant R. Choudhary, Francisco G. Cirujano, Deepa Dumbre, Sreedhar Gundekari, Sanjeev Kumar Gupta, Hari Prasad Reddy Kannapu, Navneet Kumar Gupta, Hu Li, Yan Li, Baithy Mallesham, Nuria Martín, Joyee Mitra, Deepak Raikwar, Tatiparthi Vikram Sagar, Gajanan Sahu, Debaprasad Shee, S.M.A. Hakim Siddiki, Ranjodh Singh, Young-Woong Suh, Abeda Sultana Touchy, Mohan Varkolu, Hongguo Wu, Yufei Xu, Song Yang, and Zhaozhuo Yu
- Published
- 2020
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28. Supercritical Carbon Dioxide in Esterification Reactions
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Baithy Mallesham and B. Rajender
- Subjects
Supercritical carbon dioxide ,Chemical engineering ,Chemistry - Published
- 2019
- Full Text
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29. Supported Metal Nanoparticles as Heterogeneous Catalysts for Transformation of Biomass-Derived Platform Chemicals
- Author
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Baithy, Mallesham, Shee, Debaprasad, Baithy, Mallesham, and Shee, Debaprasad
- Abstract
The lignocellulosic biomass is envisioned as a potential alternative renewable source to finite fossil fuels to produce chemicals and biofuels/biofuel additives in a sustainable manner. The efficient and economical transformation of lignocellulosic biomass into valued chemicals and biofuels is a great challenge and can be made feasible through a catalytic route. Cellulose and hemicellulose are primary constituents of the lignocellulosic biomass, and an appropriate conversion process leads to the generation of important platform chemicals such as glucose, fructose, furfural, and 5-hydroxymethylfuran (5-HMF). Catalytic valorization of these platform chemicals can produce an array of valued chemicals and biofuels/biofuel additives. Supported transition- and noble-metals-based nanoparticles as catalysts are being examined for transformation of the platform chemicals. The performance of these catalysts depends on the metal-metal and metal- support interactions and properties of supports. The influence of the catalyst properties on activity and selectivity of the desired product are briefly discussed in this chapter. The selective hydrogenation of glucose, fructose, furfural, and 5-HMF to produce d-sorbitol, d-mannitol, furfuryl alcohol, and 2,5-dimethylfuran (DMF) is considered a model reaction to correlate the catalysts' properties and activity using selected relevant literatures.
- Published
- 2020
30. Production of biofuel additives by esterification and acetalization of bioglycerol
- Author
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Bolla Govinda Rao, Benjaram M. Reddy, and Baithy Mallesham
- Subjects
Biodiesel ,General Chemical Engineering ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Furfural ,01 natural sciences ,0104 chemical sciences ,Catalysis ,chemistry.chemical_compound ,Important research ,Petrochemical ,chemistry ,Biofuel ,Acetone ,Levulinic acid ,Organic chemistry ,0210 nano-technology - Abstract
The current transition from petrochemical resources to biomass-derived platform molecules is in great demand for the development of synergies, scientific innovations and breakthroughs, and steep changes in the infrastructure of chemical industries. This article is focused on new opportunities for the production of biofuel additives from bioglycerol, which is obtained as waste and/or by-product from the current biodiesel industries. Here, we summarize the recent relevant processes for the production of biofuel additives from bioglycerol over various acid catalysts in two different pathways: (i) the esterification of bioglycerol with acetic acid, levulinic acid and other acids, and (ii) the acetalization of bioglycerol with acetone, furfural, benzaldehyde and other carbonyl compounds. It is evident that the synthesis of biofuel additives through esterfication and acetalization of bioglycerol is an important research area with imperative prospects for industrial applications.
- Published
- 2016
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31. Nanostructured Nickel/Silica Catalysts for Continuous Flow Conversion of Levulinic Acid to gamma-Valerolactone
- Author
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Putla Sudarsanam, Bellala Venkata Shiva Reddy, Baithy Mallesham, Benjaram M. Reddy, and Bolla Govinda Rao
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Valerolactone ,NI ,ESTERIFICATION ,Materials science ,General Chemical Engineering ,Chemistry, Multidisciplinary ,Nanoparticle ,chemistry.chemical_element ,010402 general chemistry ,01 natural sciences ,Redox ,CARBON NANOTUBES ,Article ,law.invention ,Catalysis ,BIOMASS ,lcsh:Chemistry ,chemistry.chemical_compound ,NI/ZRO2 CATALYSTS ,BIOFUEL ADDITIVES ,law ,Levulinic acid ,NANOPARTICLES ,BIO-ADDITIVE FUELS ,VAPOR-PHASE HYDROGENATION ,Science & Technology ,010405 organic chemistry ,General Chemistry ,0104 chemical sciences ,Nickel ,Chemistry ,ACETALIZATION ,chemistry ,Chemical engineering ,lcsh:QD1-999 ,Physical Sciences ,Particle size ,Electron microscope - Abstract
Selective transformation of levulinic acid (LA) to γ-valerolactone (GVL) using novel heterogeneous catalysts is one of the promising strategies for viable biomass processing. In this framework, we developed a continuous flow process for the selective hydrogenation of LA to GVL using several nanostructured Ni/SiO2 catalysts. The structural, textural, acidic, and redox properties of Ni/SiO2 catalysts, tuned by selectively varying the Ni amount from 5 to 40 wt %, were critically investigated using numerous materials characterization techniques. Electron microscopy images showed the formation of uniformly dispersed Ni nanoparticles on the SiO2 support, up to 30% Ni loading (average particle size is 9.2 nm), followed by a drastic increase in the particles size (21.3 nm) for 40% Ni-loaded catalyst. The fine dispersion of Ni particles has elicited a synergistic metal-support interaction, especially in 30% Ni/SiO2 catalyst, resulting in enhanced acidic and redox properties. Among the various catalysts tested, the 30% Ni/SiO2 catalyst showed the best performance with a remarkable 98% selectivity of GVL at complete conversion of LA for 2 h reaction time. Interestingly, this catalyst showed a steady selectivity to GVL (>97%), with a 54.5% conversion of LA during 20 h time-on-stream. The best performance of 30% Ni/SiO2 catalyst was attributed to well-balanced catalytic properties, such as ample amounts of strong acidic sites and abundant active metal sites. The obtained results show a great potential of applying earth-abundant nickel/silica catalysts for upgrading biomass platform molecules into value-added chemicals and high-energy-density fuels. ispartof: ACS OMEGA vol:3 issue:12 pages:16839-16849 ispartof: location:United States status: published
- Published
- 2018
32. Designing CuOx Nanoparticle-Decorated CeO2 Nanocubes for Catalytic Soot Oxidation: Role of the Nanointerface in the Catalytic Performance of Heterostructured Nanomaterials
- Author
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Mohamad Hassan Amin, Ayman Nafady, Baithy Mallesham, Putla Sudarsanam, Ali Alsalme, Brendan Hillary, Suresh K. Bhargava, B. Mahipal. Reddy, and Bolla Govinda Rao
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Materials science ,Nanoparticle ,Nanotechnology ,02 engineering and technology ,Surfaces and Interfaces ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Nanomaterials ,Catalysis ,symbols.namesake ,X-ray photoelectron spectroscopy ,Catalytic oxidation ,Transmission electron microscopy ,Electrochemistry ,symbols ,General Materials Science ,0210 nano-technology ,Raman spectroscopy ,Spectroscopy - Abstract
This work investigates the structure-activity properties of CuOx-decorated CeO2 nanocubes with a meticulous scrutiny on the role of the CuOx/CeO2 nanointerface in the catalytic oxidation of diesel soot, a critical environmental problem all over the world. For this, a systematic characterization of the materials has been undertaken using transmission electron microscopy (TEM), transmission electron microscopy-energy-dispersive X-ray spectroscopy (TEM-EDS), high-angle annular dark-field-scanning transmission electron microscopy (HAADF-STEM), scanning transmission electron microscopy-electron energy loss spectroscopy (STEM-EELS), X-ray diffraction (XRD), Raman, N2 adsorption-desorption, and X-ray photoelectron spectroscopy (XPS) techniques. The TEM images show the formation of nanosized CeO2 cubes (∼25 nm) and CuOx nanoparticles (∼8.5 nm). The TEM-EDS elemental mapping images reveal the uniform decoration of CuOx nanoparticles on CeO2 nanocubes. The XPS and Raman studies show that the decoration of CuOx on CeO2 nanocubes leads to improved structural defects, such as higher concentrations of Ce(3+) ions and abundant oxygen vacancies. It was found that CuOx-decorated CeO2 nanocubes efficiently catalyze soot oxidation at a much lower temperature (T50 = 646 K, temperature at which 50% soot conversion is achieved) compared to that of pristine CeO2 nanocubes (T50 = 725 K) under tight contact conditions. Similarly, a huge 91 K difference in the T50 values of CuOx/CeO2 (T50 = 744 K) and pristine CeO2 (T50 = 835 K) was found in the loose-contact soot oxidation studies. The superior catalytic performance of CuOx-decorated CeO2 nanocubes is mainly attributed to the improved redox efficiency of CeO2 at the nanointerface sites of CuOx-CeO2, as evidenced by Ce M5,4 EELS analysis, supported by XRD, Raman, and XPS studies, a clear proof for the role of nanointerfaces in the performance of heterostructured nanocatalysts.
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- 2016
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33. Promising nanostructured gold/metal oxide catalysts for oxidative coupling of benzylamines under eco-friendly conditions
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Agolu Rangaswamy, Benjaram M. Reddy, Suresh K. Bhargava, Putla Sudarsanam, Baithy Mallesham, and Bolla Govinda Rao
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010405 organic chemistry ,Chemistry ,Process Chemistry and Technology ,Inorganic chemistry ,Oxide ,Nanoparticle ,010402 general chemistry ,Heterogeneous catalysis ,01 natural sciences ,Catalysis ,Nanomaterial-based catalyst ,0104 chemical sciences ,chemistry.chemical_compound ,Oxidative coupling of methane ,Physical and Theoretical Chemistry ,Selectivity ,High-resolution transmission electron microscopy - Abstract
Designing Au nanocatalysts supported on nanosized metal oxides has drawn much attention due to remarkable nanoscale influenced metal-support interactions and their favorable role in heterogeneous catalysis. This work reports development of Au nanocatalysts dispersed on nanosized CeO2 and CeO2-ZrO2 supports for solvent- and base-free oxidative coupling of benzylamines into N-benzylbenzaldimines using O2 as a green oxidant. The physicochemical characterization of nanocatalysts has been undertaken using HRTEM, UV–vis DRS, XRD, Raman, BET, TG-DTA, AAS, and XPS techniques. HRTEM images reveal the formation of nanosized CeO2 and CeO2-ZrO2 supports with an average diameter of ∼10 and 7 nm, respectively. HRTEM images also indicated that Au/CeO2-ZrO2 catalyst has smaller Au nanoparticles (∼2.1 nm) compared with that of Au/CeO2 catalyst (∼3.7 nm). Raman and XPS studies showed that the addition of ZrO2 to CeO2 leads to abundant oxygen vacancies and higher concentration of Ce3+, respectively. The Au/CeO2-ZrO2 catalyst exhibited a higher efficiency in benzylamine conversion (∼95%) followed by Au/CeO2 (∼78%), CeO2-ZrO2 (∼51%), and CeO2 (∼39%). The Au/CeO2-ZrO2 catalyst was also found to effective for oxidative coupling of various benzylamines, and moderate to good product yields were obtained. The presence of smaller Au particles (2.1 nm) and improved surface-defect properties of nanoscale CeO2-ZrO2 support are found to be key factors for high performance of Au/CeO2-ZrO2 catalyst. Additionally, the reaction temperature is one of the important factors for the performance of catalysts. Remarkably, ∼99.6–99.9% selectivity for N-benzylbenzaldimines was found in the amine oxidation, which highlights the significance of present work in the selective oxidation catalysis.
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- 2016
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34. Development of cerium promoted copper–magnesium catalysts for biomass valorization: Selective hydrogenolysis of bioglycerol
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Baithy Mallesham, Putla Sudarsanam, Bellala Venkat Shiva Reddy, and Benjaram M. Reddy
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Chemistry ,Magnesium ,Coprecipitation ,Process Chemistry and Technology ,Inorganic chemistry ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Copper ,Catalysis ,0104 chemical sciences ,Cerium ,Hydrogenolysis ,Specific surface area ,0210 nano-technology ,General Environmental Science ,BET theory - Abstract
The selective hydrogenolysis of bioglycerol to 1,2-propanediol was investigated over a series of Ce-promoted Cu/Mg catalysts, namely, Cu/Mg (1/9), Cu/Ce/Mg (1/1/5), Cu/Ce/Mg (1/3/5), and Cu/Ce/Mg (1/5/5) prepared by a coprecipitation method. The physicochemical properties of the synthesized catalysts were analyzed by XRD, Raman, BET, BJH, XPS, NH3- and CO2-TPD, and H2-TPR techniques. The XRD and BET surface area results indicated that addition of Ce to Cu/Mg sample remarkably inhibits the crystal growth of CuO and improves the specific surface area. More number of oxygen vacancy defects were found in the Cu/Ce3/Mg sample, as evidenced from Raman studies. The reducible nature of the Cu/Mg sample was significantly enhanced after the Ce-incorporation. The NH3- and CO2-TPD results show that the acid–base properties of the Ce-promoted Cu/Mg samples are highly dependent on the Ce-loading. Among the synthesized samples, the Cu/Ce3/Mg sample exhibited higher concentration and superior strength of acidic sites. The achieved activity order of various catalysts for glycerol hydrogenolysis is Cu/Mg
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- 2016
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35. Highly efficient continuous-flow oxidative coupling of amines using promising nanoscale CeO2–M/SiO2 (M = MoO3 and WO3) solid acid catalysts
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Putla Sudarsanam, Baithy Mallesham, Bolla Govinda Rao, and Benjaram M. Reddy
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010405 organic chemistry ,General Chemical Engineering ,Inorganic chemistry ,Nanoparticle ,General Chemistry ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Catalysis ,chemistry.chemical_compound ,Benzylamine ,X-ray photoelectron spectroscopy ,chemistry ,Oxidative coupling of methane ,Selectivity ,Dispersion (chemistry) ,BET theory - Abstract
The development of promising solid acid catalysts alternative to hazardous liquid acids is essential towards a sustainable chemical industry. This work reports the synthesis of nanostructured CeO2–MoO3/SiO2 and CeO2–WO3/SiO2 solid acids, along with CeO2–MoO3, CeO2–WO3 and CeO2 for continuous-flow oxidative coupling of benzylamine using O2 as a green oxidant. A systematic physicochemical characterization has been undertaken using XRD, Raman, N2 adsorption–desorption, TEM, NH3-TPD, and XPS techniques. It was found that the dispersion of CeO2–MoO3 and CeO2–WO3 species on the SiO2 support leads to remarkable structural and acidic properties, due to the synergetic effect of the respective components. TEM analysis reveals the presence of highly dispersed WO3 (0.8–1.2 nm) and MoO3 (0.8–1 nm) nanoparticles in the synthesized catalysts. Among the various catalysts developed, the CeO2–MoO3/SiO2 sample exhibited higher BET surface area (248 m2 g−1), abundant oxygen vacancy defects, and large amounts of strong acidic sites. Owing to improved properties, the CeO2–MoO3/SiO2 solid-acid showed a superior catalytic performance in the continuous-flow oxidative coupling of benzylamine: the obtained benzylamine conversions for 1 h are ∼11.8, 55, 70, 76, and 96%, respectively, for CeO2, CeO2–WO3, CeO2–WO3/SiO2, CeO2–MoO3, and CeO2–MoO3/SiO2 catalysts. Importantly, the CeO2–MoO3/SiO2 solid acid exhibited a remarkable steady performance in terms of benzylamine conversion (∼88–96%) and selectivity of N-benzylbenzaldimine product (∼96–97.8%) up to 6 h. The outstanding catalytic performance of CeO2–MoO3/SiO2 solid acid coupled with the application of continuous-flow synthesis, economical benefits of the respective oxides, and eco-friendly oxidant is expected to bring new opportunities in the design of industrially-favourable chemical processes.
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- 2016
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36. β-Cyclodextrin supported MoO3–CeO2nanocomposite material as an efficient heterogeneous catalyst for degradation of phenol
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Madhukar E. Navgire, Parikshit Gogoi, Agolu Rangaswamy, Baithy Mallesham, Machhindra K. Lande, and Benjaram M. Reddy
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Ammonium bromide ,Nanocomposite ,Materials science ,General Chemical Engineering ,Inorganic chemistry ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Heterogeneous catalysis ,01 natural sciences ,0104 chemical sciences ,Catalysis ,chemistry.chemical_compound ,Adsorption ,chemistry ,Chemical engineering ,Photocatalysis ,Phenol ,Degradation (geology) ,0210 nano-technology - Abstract
With the aim of efficiently degrading organic pollutants through an easily operated procedure, a series of MoO3–CeO2 and β-cyclodextrin supported MoO3–CeO2 nano-composite materials were synthesized by using a co-precipitation method. A surfactant such as Cetyl Trimethyl Ammonium Bromide (CTAB) was used during the synthesis of this nano-composite material. These prepared catalysts are thoroughly characterized by various techniques such as XRD, BET, FT-IR, pyridine adsorbed FT-IR, Raman spectroscopy, SEM and TEM. The XRD study results suggested the formation of nanocrystalline materials which is also clearly observed from the SEM and TEM analysis. Raman measurements disclosed the presence of oxygen vacancies and lattice defects in all synthesized nano-composite samples. The catalytic activities of the synthesized materials were successfully tested for the degradation of phenol by using hydrogen peroxide at room temperature. It is surprising that the phenol degradation efficiency of the β-cyclodextrin supported MoO3–CeO2 nano-composite material is exhibited higher than that of other materials, which has been mainly attributed to the promoting effect of β-cyclodextrin. The degradation reaction is carried out at room temperature with continuous stirring and without light irradiation. Therefore, this degradation reaction is different from conventional heterogeneous catalysis or photocatalysis, in which the pollutants cannot be degraded completely, but it may transform from one phase to another phase. The gradual decrease in COD value shows the degradation of phenol that leads to the conversion of organic compounds into harmless gaseous CO2 and inorganic ions. Thus, this reported phenol degradation reaction is a quite promising green technology, which could be widely applied in practice.
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- 2016
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37. Highly efficient cerium dioxide nanocube-based catalysts for low temperature diesel soot oxidation: the cooperative effect of cerium- and cobalt-oxides
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Putla Sudarsanam, Suresh K. Bhargava, Dumbre K. Deepa, Mohamad Hassan Amin, Brendan Hillary, Benjaram M. Reddy, and Baithy Mallesham
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Cerium oxide ,Diesel exhaust ,Chemistry ,Inorganic chemistry ,chemistry.chemical_element ,medicine.disease_cause ,Catalysis ,Soot ,Cerium(IV) oxide–cerium(III) oxide cycle ,Cerium ,Catalytic oxidation ,medicine ,Cobalt - Abstract
Co3O4 promoted CeO2 nanocubes have been found to exhibit outstanding catalytic activity for the oxidation of diesel soot at low temperatures (50% soot conversion = 606 K). This remarkable performance is attributed to the superior reducible nature of cerium oxide and the preferential exposure of CeO2 (100) and Co3O4 (110) facets. A probable mechanism based on the cooperative effect of cerium- and cobalt-oxides has been proposed, offering new possibilities for the design of promising materials for catalytic soot oxidation.
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- 2015
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38. Physicochemical and catalytic properties of nanosized Au/CeO2 catalysts for eco-friendly oxidation of benzyl alcohol
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Benjaram M. Reddy, Putla Sudarsanam, Baithy Mallesham, and D. Naga Durgasri
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General Chemical Engineering ,Inorganic chemistry ,Nanoparticle ,chemistry.chemical_element ,Alcohol ,Oxygen ,Catalysis ,symbols.namesake ,chemistry.chemical_compound ,chemistry ,Colloidal gold ,Benzyl alcohol ,symbols ,Selectivity ,Raman spectroscopy ,Nuclear chemistry - Abstract
In this work, benzyl alcohol oxidation was investigated over Au/CeO 2 -homogeneous deposition–precipitation (ACH) and Au/CeO 2 -direct anionic-exchange (ACD) catalysts. Various characterization techniques were employed to study their physicochemical properties. TEM images revealed presence of 5.3 and 7.4 nm Au nanoparticles in ACH and ACD catalysts, respectively. Raman studies showed that only ACH sample exhibits oxygen deficiency (0.0574). Amongst, the ACH catalyst exhibited better catalytic performance owing to smaller gold nanoparticles and abundant oxygen vacancies. The alcohol conversion and product selectivity were strongly dependent on temperature and time-on-stream conditions. The catalytic activity decreased after repeated use due to aggregation of Au nanoparticles.
- Published
- 2014
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39. Production of Biofuel Additives from Esterification and Acetalization of Bioglycerol over SnO2-Based Solid Acids
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Benjaram M. Reddy, Baithy Mallesham, and Putla Sudarsanam
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General Chemical Engineering ,General Chemistry ,Renewable fuels ,Industrial and Manufacturing Engineering ,Catalysis ,Benzaldehyde ,chemistry.chemical_compound ,Acetic acid ,Adsorption ,chemistry ,Desorption ,Pyridine ,Organic chemistry ,BET theory - Abstract
Owing to significant environmental and economical concerns of fossil fuels, the search for alternative renewable fuels has received a explicit research interest in recent times. In this work, we prepared efficient solid acid catalysts, namely, SnO2, WO3/SnO2, MoO3/SnO2, and SO42–/SnO2 for the production of bioadditive fuels from bioglycerol under ecofriendly conditions. The synthesized samples were meticulously analyzed by means of X-ray diffraction, X-ray photoelectron spectroscopy, Brunauer–Emmett–Teller (BET) surface area, Barrett–Joyner–Halenda pore size distribution, Fourier transform infrared (FT-IR) spectroscopy, FT-IR analysis of adsorbed pyridine, NH3-temperature programmed desorption, and other techniques. The catalytic efficiency of these solid acids was investigated for esterification and acetalization of glycerol with acetic acid and benzaldehyde, respectively. Characterization studies revealed that the textural properties (crystallite size and BET surface area) of pristine SnO2 were outstand...
- Published
- 2014
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40. Nano-Au/CeO2 catalysts for CO oxidation: Influence of dopants (Fe, La and Zr) on the physicochemical properties and catalytic activity
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Putla Sudarsanam, Wolfgang Grünert, Benjaram M. Reddy, Baithy Mallesham, Dennis Großmann, and Padigapati S. Reddy
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Materials science ,Aqueous solution ,Coprecipitation ,Process Chemistry and Technology ,Metal ions in aqueous solution ,Inorganic chemistry ,Catalysis ,Metal ,X-ray photoelectron spectroscopy ,visual_art ,visual_art.visual_art_medium ,Crystallite ,General Environmental Science ,BET theory - Abstract
The present investigation was undertaken to know the influence of different dopants on the physicochemical properties and catalytic behavior of nano-Au/CeO2 catalyst for CO oxidation. Accordingly, various metal ions namely, Fe3+, La3+ and Zr4+ were incorporated into the ceria lattice by a facile coprecipitation approach using ultra-high dilute aqueous solutions. An anion adsorption method was used to prepare the Au/doped-CeO2 catalysts in the absence of any base, reducing and protective agents. The physicochemical characterization was performed by XRD, BET surface area, ICP-AES, TG-DTA, FT-IR, TEM, UV–vis DRS, Raman, XPS and TPD techniques. Doped CeO2 exhibited smaller crystallite size, higher BET surface area and larger amount of oxygen vacancies than the pure CeO2. These remarkable properties showed a beneficial effect toward gold particle size as confirmed by XRD and TEM studies. XPS results revealed that Au is present in the metallic state and Ce in both +3 and +4 oxidation states. Incorporation of Zr into the Au/CeO2 resulted in high CO oxidation activity attributed to the presence of more Ce3+ ions and oxygen vacancies. In contrast, the La-incorporation caused an opposite effect due to the presence of carbonate species on the surface of Au/CeO2–La2O3 catalyst, which blocked the active sites essential for CO oxidation. It was shown that accumulation of carbonate species strongly depends on the acid–base properties of the supports. The catalytic performance of Au catalysts is highly dependent on the nature of the support.
- Published
- 2014
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41. Physicochemical characterization and catalytic CO oxidation performance of nanocrystalline Ce–Fe mixed oxides
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Benjaram M. Reddy, Baithy Mallesham, Putla Sudarsanam, and D. Naga Durgasri
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Materials science ,Coprecipitation ,General Chemical Engineering ,Nanotechnology ,General Chemistry ,Thermal treatment ,engineering.material ,Nanocrystalline material ,law.invention ,Catalysis ,Chemical engineering ,law ,engineering ,Calcination ,Noble metal ,Crystallite ,BET theory - Abstract
The development of an efficient doped CeO2 material is an active area of intense research in environmental catalysis. In this study, we prepared highly promising Ce–Fe nano-oxides by a facile coprecipitation method and their catalytic performance was studied for CO oxidation. Various characterization techniques, namely, XRD, BET surface area, pore size distribution, Raman, FT-IR, TEM, H2-TPR, and XPS were used to correlate the structure–activity properties of the Ce–Fe catalysts. XRD results confirmed the formation of nanocrystalline Ce1−xFexO2−δ solid solution due to doping of Fe3+ into the CeO2 lattice. The BET surface area and lattice strain of CeO2 are significantly improved after the Fe-incorporation. Raman studies revealed the presence of abundant oxygen vacancies in the Ce–Fe sample. TEM images evidenced the formation of nanosized particles with an average diameter of 5–20 nm in the prepared samples. Interestingly, despite the thermal treatment at higher temperatures, the Ce–Fe sample showed remarkable reducible nature compared to pure CeO2 ascribed to existence of strong interaction between the CeO2 and FeOx. The synthesized Ce–Fe nano-oxides calcined at 773 K exhibited excellent CO oxidation performance (T50 = 480 K), with a huge difference of 131 K with respect to pure CeO2 (T50 = 611 K). The outstanding activity of the Ce–Fe catalyst is mainly due to smaller crystallite size, facile reduction, enhanced lattice strain, and ample oxygen vacancies. The superior CO oxidation performance of Ce–Fe nano-oxides with the advantages of low cost and easy availability could make them potential alternatives to noble metal-based oxidation catalysts.
- Published
- 2014
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42. Synthesis of bio–additive fuels from acetalization of glycerol with benzaldehyde over molybdenum promoted green solid acid catalysts
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Padigapati S. Reddy, Avvari N. Prasad, Putla Sudarsanam, Benjaram M. Reddy, and Baithy Mallesham
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Precipitation (chemistry) ,General Chemical Engineering ,Inorganic chemistry ,Energy Engineering and Power Technology ,chemistry.chemical_element ,Catalysis ,Benzaldehyde ,chemistry.chemical_compound ,Fuel Technology ,chemistry ,Molybdenum ,Desorption ,Glycerol ,Selectivity ,BET theory - Abstract
The heterogeneous green solid acid catalyzed acetalization of glycerol with various benzaldehydes was investigated under solvent‐free conditions. The investigated catalysts namely ZrO 2 and TiO 2 –ZrO 2 , and the respective MoO 3 promoted catalysts were prepared by a facile precipitation and wet‐impregnation method, respectively. The physicochemical characteristics were achieved using X‐ray diffraction, BET surface area, ammonia–temperature programmed desorption, Raman spectroscopy and FT–infrared spectroscopy techniques. Characterization results revealed that addition of MoO x enhances the surface acidic properties of the oxide supports. The MoO x /TiO 2 –ZrO 2 catalyst exhibited a superior 74% glycerol conversion with 51% 1,3‐dioxane product selectivity. Various reaction parameters were investigated to enhance the glycerol conversion as well as product selectivity. Particularly, the reaction temperature showed a significant influence on the glycerol conversion, whereas the effect of solvents was negligible. The conversion of glycerol was considerably decreased with substituted benzaldehydes due to steric hindrance. On the other hand, a high selectivity (71%) of 1,3‐dioxane was obtained in the case of p ‐anisaldehyde. These interesting results suggest that MoO x /TiO 2 –ZrO 2 is a highly promising green solid acid catalyst for environmentally benign synthesis of bio‐additive fuels from glycerol.
- Published
- 2013
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43. Design of highly efficient Mo and W-promoted SnO2solid acids for heterogeneous catalysis: acetalization of bio-glycerol
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Putla Sudarsanam, Benjaram M. Reddy, Gangadhara Raju, and Baithy Mallesham
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inorganic chemicals ,Inorganic chemistry ,chemistry.chemical_element ,Tungsten ,Heterogeneous catalysis ,Pollution ,Catalysis ,chemistry.chemical_compound ,Adsorption ,chemistry ,Molybdenum ,Specific surface area ,Pyridine ,Environmental Chemistry ,BET theory - Abstract
Development of highly promising solid acids is one of the key technologies to meet the essential challenges of economical and environmental concerns. Thus, novel molybdenum and tungsten promoted SnO2 solid acids (wet-impregnation) and pure SnO2 (fusion method) were prepared. The synthesized catalysts were systematically analyzed using various techniques, namely, XRD, BET surface area, pore size distribution, XPS, FTIR, FTIR of adsorbed pyridine, Raman, NH3-TPD, and H2-TPR. XRD results suggested formation of nanocrystalline SnO2 solid solutions due to the incorporation of molybdenum and tungsten cations into the SnO2 lattice. All the materials exhibited smaller crystallite size, remarkable porosity, and high specific surface area. Raman measurements suggested the formation of more oxygen vacancy defects in the doped catalysts, and the TPR results confirmed facile reduction of the doped SnO2. NH3-TPD studies revealed the beneficial role of molybdenum and tungsten oxides on the acidic properties of the SnO2. FTIR studies of adsorbed pyridine showed the existence of a larger number of Bronsted acidic sites compared to Lewis acidic sites in the prepared catalysts. The resulting catalysts are found to be efficient solid acids for acetalization of glycerol with acetone, furfural, and its derivatives under solvent-free and ambient temperature conditions. Particularly, the Mo6+-doped SnO2 catalyst exhibited excellent catalytic performance in terms of both glycerol conversion and selectivity of the products. The increased presence of acidic sites and enhanced specific surface area, accompanied by notable redox properties and superior lattice defects are found to be the decisive factors for better catalytic activity of the Mo6+-doped SnO2 sample. The investigated SnO2 solid acids represent a novel class of heterogeneous catalysts useful for the transformation of glycerol to value-added products in an eco-friendly manner.
- Published
- 2013
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44. Acetalisation of glycerol with acetone over zirconia and promoted zirconia catalysts under mild reaction conditions
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Putla Sudarsanam, Padigapati S. Reddy, Baithy Mallesham, Gangadhara Raju, and Benjaram M. Reddy
- Subjects
chemistry.chemical_compound ,chemistry ,General Chemical Engineering ,Phase (matter) ,Inorganic chemistry ,Solketal ,Acetone ,Glycerol ,Cubic zirconia ,Selectivity ,Nuclear chemistry ,BET theory ,Catalysis - Abstract
Acetalisation of biomass derived glycerol was performed with acetone over zirconia and promoted zirconia catalysts to synthesize solketal. The catalytic experiments were carried out at room temperature. It was observed that the promoted zirconia catalysts exhibit promising catalytic activity. The activity increased in the order of ZrO 2 x /ZrO 2 x /ZrO 2 4 2− /ZrO 2 . All catalysts exhibited an excellent selectivity of ∼97% towards solketal. The effect of different parameters, such as molar ratio of acetone to glycerol, catalyst wt.% and time-on-stream was studied over zirconia and promoted zirconia catalysts. The synthesized catalysts were characterized by XRD, BET surface area, ammonia-TPD and FT-Raman techniques. Characterization results revealed that the addition of promoters strongly influences the surface acidity of ZrO 2 and enhances the tetragonal zirconia phase.
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- 2011
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45. Eco-friendly synthesis of bio-additive fuels from renewable glycerol using nanocrystalline SnO2-based solid acids
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Baithy Mallesham, Benjaram M. Reddy, and Putla Sudarsanam
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chemistry.chemical_compound ,Adsorption ,chemistry ,Oxidation state ,Pyridine ,Acetone ,Glycerol ,Organic chemistry ,Furfural ,Catalysis ,BET theory - Abstract
The present work has been undertaken with an aim to synthesize valuable bio-additive fuels from glycerol acetalization using SnO2-based solid acids. Various promoters, namely SO42−, MoO3 and WO3 were incorporated to the SnO2 using a wet-impregnation method. An extensive physicochemical characterization has been achieved by means of XRD, BET surface area, BJH analysis, FT-IR, pyridine adsorbed FT-IR, NH3-TPD, ICP-OES and XPS techniques. The BET surface area of SnO2 is significantly improved from 11 to 32, 56 and 41 m2 g−1 after the addition of the WO3, MoO3, and SO42− promoters, respectively. The XPS studies revealed that Sn is present in the +4 oxidation state, whereas Mo, W and S are in the +6 oxidation state in the prepared samples. In addition, the SO42−/SnO2 sample contained super acidic sites, along with strong- and medium-acidic sites. The amount of acidic sites was found to be 46.47, 61.81, 81.45 and 186.98 μmol g−1 for the SnO2, WO3/SnO2, MoO3/SnO2, and SO42−/SnO2 samples, respectively. The pyridine adsorbed FT-IR studies revealed the existence of a superior quantity of Bronsted acidic sites than Lewis acidic sites in the synthesized catalysts. Promoted SnO2 catalysts exhibited a promising catalytic performance for glycerol acetalization with acetone and furfural, and the activity of the catalysts was found to increase in the following order: SnO2 < WO3/SnO2 < MoO3/SnO2 < SO42−/SnO2. The outstanding performance of the SO42−/SnO2 catalyst is mainly due to the existence of a large amount of acidic sites associated with the super acidic sites. The achieved optimum glycerol conversions with acetone and furfural were ~98 and 99% over the SO42−/SnO2 catalyst, respectively.
- Published
- 2014
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46. Preparation of silica supported ceria–lanthana solid solutions useful for synthesis of 4-methylpent-1-ene and dehydroacetic acid
- Author
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Benjaram M. Reddy, Putla Sudarsanam, Baithy Mallesham, and Lakshmi Katta
- Subjects
Diffuse reflectance infrared fourier transform ,Chemistry ,Thermal desorption spectroscopy ,Coprecipitation ,Inorganic chemistry ,Dehydroacetic acid ,Catalysis ,chemistry.chemical_compound ,symbols.namesake ,X-ray photoelectron spectroscopy ,symbols ,Organic chemistry ,Raman spectroscopy ,BET theory - Abstract
The intriguing research toward the exploitation of ceria-based materials for various applications has been growing significantly. In the present investigation, we describe the preparation, characterization and utilization of CeO2–La2O3 (CL) and CeO2–La2O3/SiO2 (CLS) solid solutions for the synthesis of two industrially useful chemicals namely 4-methylpent-1-ene and dehydroacetic acid. Coprecipitation and deposition coprecipitation from ultrahigh dilute solutions were used for the synthesis of CL and CLS catalysts, respectively. The physicochemical characterization has been achieved with the help of various techniques namely X-ray diffraction (XRD), BET surface area, transmission electron microscopy (TEM), UV-visible diffuse reflectance spectroscopy (UV-vis DRS), Raman spectroscopy (UV-RS and Vis-RS), X-ray photoelectron spectroscopy (XPS) and temperature programmed desorption (TPD) measurements. The structure–activity relationships helped to correlate different parameters that are necessary for obtaining desired products in good yields. The inclusion of silica support has an optimistic influence on the acid–base properties of the ceria–lanthana, in terms of both amount and strength of sites. The presence of silica not only manipulates the acid–base properties but also causes numerous benefits, for instance, it improves the dispersion, stabilizes the active component against sintering and enriches the oxygen vacancy concentration. The meticulous analysis of characterization and activity studies revealed the significant role of acid–base sites in directing the desired products. Interestingly, the CLS catalyst has shown better performance in the production of both 4-methylpent-1-ene and dehydroacetic acid compared to the unsupported CL sample due to well-balanced acid–base sites.
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- 2012
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47. Rational design and investigation of nonlinear optical response properties of pyrrolopyrrole aza-BODIPY-based novel push-pull chromophores.
- Author
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Kothoori NPS, Sivasakthi P, Baithy M, Misra R, and Samanta PK
- Abstract
Intramolecular charge transfer (ICT)-based chromophores are highly sought after for designing near-infrared (NIR) absorbing and emitting dyes as well as for designing materials for nonlinear optical (NLO) applications. The properties of these 'push-pull' molecules can easily be modified by varying the electronic donor (D) and acceptor (A) groups as well as the π-conjugation linker. This study presents a methodical approach and employs quantum chemical analysis to explore the relationship between the structural features, electro-optical properties, and the NLO characteristics of molecules with D-π-A framework. The one- and two-photon absorption (2PA), linear polarizability ( α ), and first hyperpolarizability ( β ) of some novel chromophores, consisting of a dimeric aza-Boron Dipyrromethene (aza-BODIPY) analogue, called, pyrrolopyrrole aza-BODIPY (PPAB), serving as the acceptor, have been investigated. The electronic donors used in this study are triphenylamine (TPA) and diphenylamine (DPA), and they are conjugated to the acceptor via thienyl or phenylene π-linkers. Additionally, the Hyper-Rayleigh Scattering ( β
HRS ), which enables direct estimation of the second-order NLO properties, is calculated for the studied chromophores with 1064 nm excitation in acetonitrile. The β value shows a significant increase with increasing solvent polarity, indicating that the ICT plays a crucial role in shaping the NLO response of the studied molecules. The enhancement of the 2PA cross-section of the investigated molecules can also be achieved by modulating the combinations of donors and linkers. The results of our study indicate that the novel D-π-A molecules designed in this work demonstrate considerably higher hyperpolarizability values than the standard p -nitroaniline, making them promising candidates for future NLO applications., Competing Interests: The authors declare no competing financial interest., (This journal is © The Royal Society of Chemistry.)- Published
- 2024
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48. The role of WO x and dopants (ZrO 2 and SiO 2 ) on CeO 2 -based nanostructure catalysts in the selective oxidation of benzyl alcohol to benzaldehyde under ambient conditions.
- Author
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Bathula G, Rana S, Bandalla S, Dosarapu V, Mavurapu S, Rajeevan V V A, Sharma B, Jonnalagadda SB, Baithy M, and Vasam CS
- Abstract
Herein, the efficacy of WO
x -promoted CeO2 -SiO2 and CeO2 -ZrO2 mixed oxide catalysts in the solvent-free selective oxidation of benzyl alcohol to benzaldehyde using molecular oxygen as an oxidant is reported. We evaluated the effects of the oxidant and catalyst concentration, reaction duration, and temperature on the reaction with an aim to optimize the reaction conditions. The as-prepared CeO2 , CeO2 -ZrO2 , CeO2 -SiO2 , WOx /CeO2 , WOx /CeO2 -ZrO2 , and WOx /CeO2 -SiO2 catalysts were characterized by X-ray diffraction (XRD), N2 adsorption-desorption, Raman spectroscopy, temperature-programmed desorption of ammonia (TPD-NH3 ), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). These characterisation results indicated that the WOx /CeO2 -SiO2 catalyst possessed improved physicochemical ( i.e. , structural, textural, and acidic) properties owing to the strong interactivity between WOx and CeO2 -SiO2 . A higher number of Ce3+ ions ( Iu''' / ITotal ) were created with the WOx /CeO2 -SiO2 catalyst than those with the other catalysts in this work, indicating the generation of a high number of oxygen vacancies. The WOx /CeO2 -SiO2 catalyst exhibited a high conversion of benzyl alcohol (>99%) and a high selectivity (100%) toward benzaldehyde compared to the other promoted catalysts ( i.e. , WOx /CeO2 and WOx /CeO2 -ZrO2 ), which is attributed to the smaller particle size of the WOx and CeO2 and their high specific surface area, more significant number of acidic sites, and superior number of oxygen vacancies. The WOx /CeO2 -SiO2 catalyst could be quickly recovered and utilized at least five times without suffering any appreciable activity loss., Competing Interests: The authors declare no conflict of interest., (This journal is © The Royal Society of Chemistry.)- Published
- 2023
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