scholarly journals Solvent-Free Synthesis of SAPO-34 Zeolite with Tunable SiO2/Al2O3 Ratios for Efficient Catalytic Cracking of 1-Butene

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 835
Author(s):  
Xia Xiao ◽  
Zhongliang Xu ◽  
Peng Wang ◽  
Xinfei Liu ◽  
Xiaoqiang Fan ◽  
...  
Keyword(s):  
Catalytic Cracking ◽  
Acid Sites ◽  
Solvent Free ◽  
Zeolite Catalysts ◽  
Light Olefins ◽  
Molar Ratio ◽  
Coordination Environment ◽  
Starting Mixture ◽  
Synthesis Methodology ◽  
Solvent Free Synthesis

Solvent-free synthesis methodology is a promising technique for the green and sustainable preparation of zeolites materials. In this work, a solvent-free route was developed to synthesize SAPO-34 zeolite. The characterization results indicated that the crystal size, texture properties, acidity and Si coordination environment of the resulting SAPO-34 were tuned by adjusting the SiO2/Al2O3 molar ratio in the starting mixture. Moreover, the acidity of SAPO-34 zeolite was found to depend on the Si coordination environment, which was consistent with that of SAPO-34 zeolite synthesized by the hydrothermal method. At an SiO2/Al2O3 ratio of 0.6, the SP-0.6 sample exhibited the highest conversion of 1-butene (82.8%) and a satisfactory yield of light olefins (51.6%) in the catalytic cracking of 1-butene, which was attributed to the synergistic effect of the large SBET (425 m2/g) and the abundant acid sites (1.82 mmol/g). This work provides a new opportunity for the design of efficient zeolite catalysts for industrially important reactions.

scholarly journals Solvent-Free Synthesis of Jasminaldehyde in a Fixed-Bed Flow Reactor over Mg-Al Mixed Oxide

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1033
Author(s):  
Zahra Gholami ◽  
Zdeněk Tišler ◽  
Pavla Vondrová ◽  
Romana Velvarská ◽  
Kamil Štěpánek
Keyword(s):  
Organic Compounds ◽  
Lewis Acid ◽  
Flow Reactor ◽  
Fixed Bed ◽  
Acid Sites ◽  
Economic Benefits ◽  
Solvent Free ◽  
Molar Ratio ◽  
Lewis Acid Sites ◽  
Solvent Free Synthesis

In spite of the rapid developments in synthesis methodologies in different fields, the traditional methods are still used for the synthesis of organic compounds, and regardless of the type of chemistry, these reactions are typically performed in standardized glassware. The high-throughput chemical synthesis of organic compounds such as fragrant molecules, with more economic benefits, is of interest to investigate and develop a process that is more economical and industrially favorable. In this research, the catalytic activity of Mg-Al catalyst derived from hydrotalcite-like precursors with the Mg/Al molar ratio of 3 was investigated for the solvent-free synthesis of jasminaldehyde via aldol condensation of benzaldehyde and heptanal. The reaction was carried out in a fixed-bed flow reactor, at 1 MPa, and at different temperatures. Both Brønsted and Lewis (O2− anions) base sites, and Lewis acid sites exist on the surface of the Mg-Al catalyst, which can improve the catalytic performance. Increasing the reaction temperature from 100 °C to 140 °C enhanced both heptanal conversion and selectivity to jasminaldehyde. After 78 h of reaction at 140 °C, the selectivity to jasminaldehyde reached 41% at the heptanal conversion 36%. Self-condensation of heptanal also resulted in the formation of 2-n-pentyl-2-n-nonenal. The presence of weak Lewis acid sites creates a positive charge on the carbonyl group of benzaldehyde, and makes it more prone to attack by the carbanion of heptanal. Heptanal, is an aliphatic aldehyde, with higher activity than benzaldehyde. Therefore, the possibility of activated heptanal reacting with other heptanal molecules is higher than its reaction with the positively charged benzaldehyde molecule, especially at a low molar ratio of benzaldehyde to heptanal.

scholarly journals Lipase-catalyzed Solvent-free Synthesis of Polyglycerol 10 (PG-10) Esters

2020 ◽  
Vol 33 (4) ◽  
pp. 501-509
Author(s):  
Yamini Satyawali ◽  
Lieve Cawenberghs ◽  
Winnie Dejonghe
Keyword(s):  
Fatty Acid ◽  
Molecular Sieves ◽  
Enzymatic Synthesis ◽  
Solvent Free ◽  
Fatty Acid Esters ◽  
Molar Ratio ◽  
Cosmetic Industry ◽  
The Subject ◽  
Solvent Free Synthesis ◽  
Acid Esters

Polyglycerol fatty acid esters, which have been widely used as emulsifiers in food, medicine and cosmetics industries, were the subject of solvent-free enzymatic synthesis<br /> in this study. There have been previous reports on enzymatic synthesis of various polyglycerol esters; however, this investigation extends the synthesis to PG-10 esters. The<br /> effects of substrate molar ratio, addition of emulsifiers to enhance mixing, and addition of molecular sieves or N2 flushing for water removal, was investigated. The solvent-free synthesis using N2 flushing leads to complete conversion of fatty acid, yielding a completely acid free product. The synthesis is validated for polyglycerol laurate and polyglycerol caprylate, both useful products in the cosmetic industry.

scholarly journals Microwave Assisted Solvent-Free Synthesis of Some Imine Derivatives

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Yunus Bekdemir ◽  
Kürşat Efil
Keyword(s):  
Microwave Heating ◽  
Aromatic Amines ◽  
Environmentally Friendly ◽  
Aromatic Aldehydes ◽  
Solvent Free ◽  
Molar Ratio ◽  
Microwave Assisted ◽  
Solvent Free Conditions ◽  
Solvent Free Synthesis ◽  
Environmentally Friendly Method

Some imine derivatives (1a–7d) were synthesized using a rapid and an environmentally friendly method with reaction of aromatic aldehydes (a–d) and aromatic amines (1–7) (in 1 : 1 molar ratio) in the presence of β-ethoxyethanol as a wetting reagent (2 drops) under solvent-free conditions using microwave heating.

scholarly journals Modulating Inherent Lewis Acidity at the Intergrowth Interface of Mortise-Tenon Zeolite Catalyst

2021 ◽  
Author(s):  
Huiqiu Wang ◽  
Boyuan Shen ◽  
Xiao Chen ◽  
Hao Xiong ◽  
Hongmei Wang ◽  
...  
Keyword(s):  
Single Crystal ◽  
Lattice Mismatch ◽  
Methanol Conversion ◽  
Scanning Transmission Electron Microscope ◽  
Acid Sites ◽  
Zeolite Catalysts ◽  
Lewis Acidity ◽  
Light Olefins ◽  
Local Structures ◽  
Catalytic Performances

Abstract The tunability of local structures determines various catalytic performances of zeolite catalysts. The acid sites in zeolite catalysts are important local structures to control the products in methanol conversion. However, it remained still a great challenge to precisely design the acid sites, since there is a lack of controllable methods to generate and identify the acid sites with a high resolution. Here, we use the lattice mismatch of zeolite intergrowth to enrich the inherent Lewis acid sites (LASs) at the interface of a mortise-tenon ZSM-5 catalyst (ZSM-5-MT) showing a 90° intergrowth structure. ZSM-5-MT is formed by two perpendicular blocks that can be atomically resolved by the integrated differential phase contrast scanning transmission electron microscope (iDPC-STEM). It can be revealed by various methods that more framework-associated Al (AlFR) LASs are generated in ZSM-5-MT than single-crystal ZSM-5 catalyst. Combining with the iDPC-STEM results, we demonstrate that the partial missing of O atoms at interfaces results in the formation of inherent LASs in ZSM-5-MT. According to the catalytic performances, LAS-enriched ZSM-5-MT shows a higher selectivity of light olefins than the single-crystal ZSM-5 catalyst in methanol conversion. These results provide an efficient strategy to design the Lewis acidity in zeolites for tailored catalytic functions via interface engineering.

Preparation of Phosphorus Modified HZSM-5 Zeolite Catalysts and their Catalytic Performances of Methanol to Olefins

2014 ◽  
Vol 875-877 ◽  
pp. 295-299
Author(s):  
Shu Xun Tian ◽  
Sheng Fu Ji ◽  
Qi Sun
Keyword(s):  
Phosphorus Content ◽  
Strong Acid ◽  
Weight Percent ◽  
Acid Sites ◽  
Zeolite Catalysts ◽  
Light Olefins ◽  
Microporous Structure ◽  
Phosphorous Content ◽  
Propylene Yield ◽  
Strong Acid Sites

To improve the selectivity of light olefins, Phosphorous modified ZSM-5 zeolites catalysts with different phosphorous content were prepared by impregnation and were used in the conversion of methanol to olefins. The properties of acidity and microporous structure of the phosphorous modified ZSM-5 zeolites were investigated by XRD, N2-adsorption and desorption, and NH3-TPD. The highest propylene yield (50.82%) was observed over the H-ZSM-5 modified with the phosphorus content at 9% (weight percent). The selectivity of propylene depended strongly on the phosphorus content in the zeolites; The enhancement of propylene selectivity with increasing phosphorous content was attributed to reduction of strong acid sites on the H-ZSM-5. Modification of the ZSM-5 zeolites with phosphorous also changes the microporous structure.

Solvent-free synthesis of zeolite catalysts

2014 ◽  
Vol 58 (1) ◽  
pp. 6-13 ◽  
Author(s):  
Xiangju Meng ◽  
Qinming Wu ◽  
Fang Chen ◽  
Feng-Shou Xiao
Keyword(s):  
Solvent Free ◽  
Zeolite Catalysts ◽  
Solvent Free Synthesis

scholarly journals Nano BEA zeolite catalysts for the selective catalytic cracking of n-dodecane to light olefins

RSC Advances ◽  
2021 ◽  
Vol 11 (14) ◽  
pp. 7904-7912
Author(s):  
Galal A. Nasser ◽  
M. H. M. Ahmed ◽  
Mochamad A. Firdaus ◽  
Mohammed A. Sanhoob ◽  
Idris A. Bakare ◽  
...  
Keyword(s):  
Catalytic Cracking ◽  
Zeolite Catalysts ◽  
Light Olefins ◽  
Bea Zeolite

Nano BEA zeolite catalysts were synthesized and modified by desilication and then ion-exchanged with Co. The desilication was carried out using 0.1 M of NaOH.

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