1
|
Trindade ACM, Enzweiler H, Salau NPG. Modeling and optimizing the synthesis of isopropyl acetate over niobium pentoxide using experimental design methodology coupled with artificial neural network. CHEM ENG COMMUN 2023. [DOI: 10.1080/00986445.2023.2174861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Affiliation(s)
- Aline C. M. Trindade
- Departamento de Engenharia Química, Universidade Federal de Santa Maria, Santa Maria, Brazil
| | - Heveline Enzweiler
- Departamento de Engenharia de Alimentos e Engenharia Química, Universidade do Estado de Santa Catarina, Florianopolis, Brazil
| | - Nina P. G. Salau
- Departamento de Engenharia Química, Universidade Federal de Santa Maria, Santa Maria, Brazil
| |
Collapse
|
2
|
Synthesis of propyl acetate by sulfated zirconia: kinetics and mechanism modeling. REACTION KINETICS MECHANISMS AND CATALYSIS 2023. [DOI: 10.1007/s11144-023-02353-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
|
3
|
Delarmelina M, Deshmukh G, Goguet A, Catlow CRA, Manyar H. Role of Sulfation of Zirconia Catalysts in Vapor Phase Ketonization of Acetic Acid. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2021; 125:27578-27595. [PMID: 34970379 PMCID: PMC8713292 DOI: 10.1021/acs.jpcc.1c06920] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 11/17/2021] [Indexed: 06/14/2023]
Abstract
The effect of the sulfation of zirconia catalysts on their structure, acidity/basicity, and catalytic activity/selectivity toward the ketonization of organic acids is investigated by a combined experimental and computational method. Here, we show that, upon sulfation, zirconia catalysts exhibit a significant increase in their Brønsted and Lewis acid strength, whereas their Lewis basicity is significantly reduced. Such changes in the interplay between acid-base sites result in an improvement of the selectivity toward the ketonization process, although the measured conversion rates show a significant drop. We report a detailed DFT investigation of the putative surface species on sulfated zirconia, including the possible formation of dimeric pyrosulfate (S2O7 2-) species. Our results show that the formation of such a dimeric system is an endothermic process, with energy barriers ranging between 60.0 and 70.0 kcal mol-1, and which is likely to occur only at high SO4 2- coverages (4 S/nm2), high temperatures, and dehydrating conditions. Conversely, the formation of monomeric species is expected at lower SO4 2- coverages, mild temperatures, and in the presence of water, which are the usual conditions experienced during the chemical upgrading of biofuels.
Collapse
Affiliation(s)
- Maicon Delarmelina
- School
of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, United Kingdom
- UK
Catalysis Hub, Research Complex at Harwell, STFC Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0FA, United Kingdom
| | - Gunjan Deshmukh
- UK
Catalysis Hub, Research Complex at Harwell, STFC Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0FA, United Kingdom
- School
of Chemistry and Chemical Engineering, Queen’s
University Belfast, David-Keir Building, Stranmillis Road, Belfast BT9 5AG, United Kingdom
| | - Alexandre Goguet
- UK
Catalysis Hub, Research Complex at Harwell, STFC Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0FA, United Kingdom
- School
of Chemistry and Chemical Engineering, Queen’s
University Belfast, David-Keir Building, Stranmillis Road, Belfast BT9 5AG, United Kingdom
| | - C. Richard A. Catlow
- School
of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, United Kingdom
- UK
Catalysis Hub, Research Complex at Harwell, STFC Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0FA, United Kingdom
- Department
of Chemistry, University College London, 20 Gordon St., London WC1 HOAJ, United
Kingdom
| | - Haresh Manyar
- UK
Catalysis Hub, Research Complex at Harwell, STFC Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0FA, United Kingdom
- School
of Chemistry and Chemical Engineering, Queen’s
University Belfast, David-Keir Building, Stranmillis Road, Belfast BT9 5AG, United Kingdom
| |
Collapse
|
4
|
Trindade ACM, Enzweiler H, Salau NPG. New insights into reaction-diffusion kinetic coupling in the esterification of acetic acid with isopropanol over niobium pentoxide. CHEM ENG COMMUN 2021. [DOI: 10.1080/00986445.2021.2009810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
| | - Heveline Enzweiler
- Departamento de Engenharia de Alimentos e Engenharia Química, Universidade do Estado de Santa Catarina, Brazil
| | - Nina P. G. Salau
- Departamento de Engenharia Química, Universidade Federal de Santa Maria, Brazil
| |
Collapse
|
6
|
A Theoretical and Experimental Study on Esterification of Citric Acid with the Primary Alcohols and the Hydroxyl Groups of Cellulose Chain (n = 1-2) in Parched Condition. J CHEM-NY 2020. [DOI: 10.1155/2020/8825456] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Esterification of citric acid (CA) with the primary alcohols and the hydroxyl groups of cellulose chain (n = 1-2) in parched condition were investigated by using density functional theory (DFT) method and a two-layer ONIOM approach. Geometry and energy of reactants, products, and transition state (TS) structures were optimized at B3LYP/6-311g (d, p) level and ONIOM (B3LYP/6-311g (d, p):PM3MM) level. The computational results show that the esterification occurs in the two main steps: the first step is the dehydration reaction of CA to form anhydrides of 5-membered ring and 6-membered ring and the second step is the ring opening reaction with the hydroxyl –OH groups to form the ester products. The energy barrier of dehydration reaction step is much higher than that of ring opening reaction step. Effect of substituent R in primary alcohol R-CH2OH (R: CH=CH2, CH2NHCH3, CH2OCH3, CH2Cl) and cellulose chain (1G, 2G) on the reactivity, which has negative inductive effect –I, is significant. The combination of calculation data and experiment data were applied to make findings more rigorous. The activation energy of CA was determined by using differential scanning calorimetry (DSC) and thermal gravimetric (TG) analysis to be
= 47.8 kcal/mol; the experimental data favoured the dehydration reaction step of CA.
Collapse
|