1
|
Liu Z, Mao M, Yangcheng R, Lv S. Investigating the Sole Olefin-Based Cycle in Small-Cage MCM-35-Catalyzed Methanol-to-Olefins Reactions. Molecules 2024; 29:2037. [PMID: 38731528 DOI: 10.3390/molecules29092037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 04/10/2024] [Accepted: 04/26/2024] [Indexed: 05/13/2024] Open
Abstract
Small-pore zeolites catalyze the methanol-to-olefins (MTO) reaction via a dual-cycle mechanism, encompassing both olefin- and aromatic-based cycles. Zeolite topology is crucial in determining both the catalytic pathway and the product selectivity of the MTO reaction. Herein, we investigate the mechanistic influence of MCM-35 zeolite on the MTO process. The structural properties of the as-synthesized MCM-35 catalyst, including its confined cages (6.19 Å), were characterized, confirming them as the catalytic centers. Then, the MTO reactions were systematically performed and investigated over a MCM-35 catalyst. Feeding pure methanol to the reactor yielded minimal MTO activity despite the formation of some aromatic species within the zeolite. The results suggest that the aromatic-based cycle is entirely suppressed in MCM-35, preventing the simultaneous occurrence of the olefin-based cycle. However, cofeeding a small amount of propene in methanol can obviously enhance the methanol conversion under the same studied reaction conditions. Thus, the exclusive operation of the olefin-based cycle in the MTO reaction, independent of the aromatic-based cycle, was demonstrated in MCM-35 zeolite.
Collapse
Affiliation(s)
- Zhaohui Liu
- Institute of Advanced Interdisciplinary Studies, School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044, China
| | - Min Mao
- Institute of Advanced Interdisciplinary Studies, School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044, China
| | - Ruixue Yangcheng
- Institute of Advanced Interdisciplinary Studies, School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044, China
| | - Shuang Lv
- Institute of Advanced Interdisciplinary Studies, School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044, China
| |
Collapse
|
2
|
Zhou Z, Wang X, Li J, Gao Y, Yu R, Jiang R. One-pot Synthesis of Phosphorus-modified ZSM-5 Zeolite by Solid-state Method and its MTO Catalytic Performance. Chemistry 2023; 29:e202203095. [PMID: 36478597 DOI: 10.1002/chem.202203095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 12/02/2022] [Accepted: 12/06/2022] [Indexed: 12/12/2022]
Abstract
The traditional hydrothermal synthesis strategy of ZSM-5 zeolite is energy-consumption accompanying by pollution issues. Herein, phosphorus-modified layered ZSM-5 zeolites (PZ) were obtained by one-pot synthesis under solvent-free conditions. The synthesized samples were fully characterized by XRD, SEM, BET, NH3 -TPD and FTIR. The effect of phosphorus addition on the morphology and catalytic activity of ZSM-5 was investigated. The results showed that phosphorus-modified ZSM-5 zeolites exhibited higher light olefin (ethylene and propylene) selectivity (above 50 %) and longer catalytic lifetime (33 h) in methanol to olefin (MTO) reaction when the weight hourly space velocity was 4 h-1 . Phosphorus-modified ZSM-5 zeolite synthesized by in situ solvent-free method, which not only reduced the discharge of sewage but also showed a simple method to realize the introduction of phosphorous species, which provided a new idea for phosphorus modification of ZSM-5 zeolite.
Collapse
Affiliation(s)
- Zihan Zhou
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou, 221116 (P. R., China
| | - Xingwen Wang
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou, 221116 (P. R., China
| | - Junjie Li
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou, 221116 (P. R., China
| | - Yu Gao
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou, 221116 (P. R., China
| | - Rui Yu
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou, 221116 (P. R., China
| | - Rongli Jiang
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou, 221116 (P. R., China
| |
Collapse
|
3
|
Xie J, Firth DS, Cordero-Lanzac T, Airi A, Negri C, Øien-Ødegaard S, Lillerud KP, Bordiga S, Olsbye U. MAPO-18 Catalysts for the Methanol to Olefins Process: Influence of Catalyst Acidity in a High-Pressure Syngas (CO and H 2) Environment. ACS Catal 2022; 12:1520-1531. [PMID: 35096471 PMCID: PMC8788383 DOI: 10.1021/acscatal.1c04694] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 12/12/2021] [Indexed: 12/01/2022]
Abstract
The transition from integrated petrochemical complexes toward decentralized chemical plants utilizing distributed feedstocks calls for simpler downstream unit operations. Less separation steps are attractive for future scenarios and provide an opportunity to design the next-generation catalysts, which function efficiently with effluent reactant mixtures. The methanol to olefins (MTO) reaction constitutes the second step in the conversion of CO2, CO, and H2 to light olefins. We present a series of isomorphically substituted zeotype catalysts with the AEI topology (MAPO-18s, M = Si, Mg, Co, or Zn) and demonstrate the superior performance of the M(II)-substituted MAPO-18s in the conversion of MTO when tested at 350 °C and 20 bar with reactive feed mixtures consisting of CH3OH/CO/CO2/H2. Co-feeding high pressure H2 with methanol improved the catalyst activity over time, but simultaneously led to the hydrogenation of olefins (olefin/paraffin ratio < 0.5). Co-feeding H2/CO/CO2/N2 mixtures with methanol revealed an important, hitherto undisclosed effect of CO in hindering the hydrogenation of olefins over the Brønsted acid sites (BAS). This effect was confirmed by dedicated ethene hydrogenation studies in the absence and presence of CO co-feed. Assisted by spectroscopic investigations, we ascribe the favorable performance of M(II)APO-18 under co-feed conditions to the importance of the M(II) heteroatom in altering the polarity of the M-O bond, leading to stronger BAS. Comparing SAPO-18 and MgAPO-18 with BAS concentrations ranging between 0.2 and 0.4 mmol/gcat, the strength of the acidic site and not the density was found to be the main activity descriptor. MgAPO-18 yielded the highest activity and stability upon syngas co-feeding with methanol, demonstrating its potential to be a next-generation MTO catalyst.
Collapse
Affiliation(s)
- Jingxiu Xie
- Centre
for Materials Science and Nanotechnology, Department of Chemistry, University of Oslo, Sem Saelandsvei 26, Oslo N-0315, Norway
| | - Daniel S. Firth
- Centre
for Materials Science and Nanotechnology, Department of Chemistry, University of Oslo, Sem Saelandsvei 26, Oslo N-0315, Norway
| | - Tomás Cordero-Lanzac
- Centre
for Materials Science and Nanotechnology, Department of Chemistry, University of Oslo, Sem Saelandsvei 26, Oslo N-0315, Norway
| | - Alessia Airi
- Department
of Chemistry, NIS and INSTM Reference Centre, Università di Torino, Via G. Quarello 15, I-10135 and Via P. Giuria 7, Torino 10125, Italy
| | - Chiara Negri
- Centre
for Materials Science and Nanotechnology, Department of Chemistry, University of Oslo, Sem Saelandsvei 26, Oslo N-0315, Norway
| | - Sigurd Øien-Ødegaard
- Centre
for Materials Science and Nanotechnology, Department of Chemistry, University of Oslo, Sem Saelandsvei 26, Oslo N-0315, Norway
| | - Karl Petter Lillerud
- Centre
for Materials Science and Nanotechnology, Department of Chemistry, University of Oslo, Sem Saelandsvei 26, Oslo N-0315, Norway
| | - Silvia Bordiga
- Department
of Chemistry, NIS and INSTM Reference Centre, Università di Torino, Via G. Quarello 15, I-10135 and Via P. Giuria 7, Torino 10125, Italy
| | - Unni Olsbye
- Centre
for Materials Science and Nanotechnology, Department of Chemistry, University of Oslo, Sem Saelandsvei 26, Oslo N-0315, Norway
| |
Collapse
|
4
|
Rimaz S, Katal R. Positive Role of Synthesis Method and Hard Template on the Catalytic Performance of SAPO-34 in Methanol to Olefin Reaction. Comb Chem High Throughput Screen 2020; 24:485-489. [PMID: 32691709 DOI: 10.2174/1386207323666200720103321] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 05/17/2020] [Accepted: 05/20/2020] [Indexed: 11/22/2022]
Abstract
In the present study, SAPO-34 particles were synthesized using hydrothermal (HT) and dry gel (DG) conversion methods in the presence of diethyl amine (DEA) as an organic structure directing agent (SDA). Carbon nanotubes (CNT) were used as a hard template in the synthesis procedure to introduce transport pores into the structures of the synthesized samples. The synthesized samples were characterized with different methods to reveal the effects of synthesis method and using hard template on their structure and catalytic performance in methanol to olefin reaction (MTO). DG conversion method results in smaller particle size in comparison with hydrothermal method, resulting in enhancing catalytic performance. On the other side, using CNT in the synthesis procedure with DG method results in more reduction in particle size and formation of hierarchical structure, which drastically improves catalytic performance.
Collapse
Affiliation(s)
- Sajjad Rimaz
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585, Singapore
| | - Reza Katal
- Department of Civil & Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, 117576, Singapore
| |
Collapse
|