Improved synthesis and study of acidic properties of ‘plugs’-containing Al-SBA-15 materials

2010 ◽  
Vol 76 (1) ◽  
pp. 39-49 ◽  
Author(s):  
ZhiQi Jia ◽  
YongXiang Zhao
Keyword(s):  
Catalytic Activity ◽  
Pore Wall ◽  
Point Of View ◽  
Polymerization Reaction ◽  
Acidic Properties ◽  
Acidic Sites ◽  
Pore Wall Thickness ◽  
Aluminum Precursor ◽  
Large Pore Size ◽  
Mcm 41

A novel ‘plugs’-containing Al-SBA-15 material (denoted as PAS) was directly synthesized through simultaneous introducing toluene and aluminum precursor into the reaction mixture of traditional SBA-15. Such material not only featured a unique two-step desorption isotherm as conventional plugged SBA-15 synthesized using excessive siliceous precursor, and higher pore wall thickness than that of other analogous materials, but also possessed weak and medium acidic sites, which implied the PAS would offer unusual advantages such as multifunctionality to process a large variety of feed-stocks in acid-involved reaction (e.g. polymerization of tetrahydrofuran) in industrial point of view. In addition, catalytic activity of the PAS was investigated by the tetrahydrofuran (THF) polymerization reaction in the presence of acetic anhydride and compared with Al-doped MCM-41 prepared via conventional direct hydrothermal synthesis. The PAS exhibited good performance on polymerization of THF. Such result could be related to the large pore size and moderate acidic sites.

Synthesis and Characterizations of MCM-41 Silica with Thick Pore Wall

2011 ◽  
Vol 233-235 ◽  
pp. 2034-2037
Author(s):  
Qiong Wei Hou ◽  
En Hui Yuan ◽  
Jin Gang Jiang ◽  
Kun Zhang
Keyword(s):  
High Temperature ◽  
Mesoporous Silica ◽  
Wall Thickness ◽  
Pore Wall ◽  
Crystallization Time ◽  
Pore Channel ◽  
Desorption Branch ◽  
Cetyltrimethylammonium Tosylate ◽  
Pore Wall Thickness ◽  
Mcm 41

Nano-structured mesoporous silica with highly ordered 2D hexagonal topology has been synthesized using novel surfactant cetyltrimethylammonium tosylate (CTATos) as template via directly hydrothermal treatment at high temperature of 175 °C and varied crystallization time. The maximum pore wall thickness is up to 2.2 nm calculated by BdB method from desorption branch. The enlargement of pore wall thickness and unit-lattice of currently synthesized MCM-41 silica is attributed to the migration and subsequent deposition of the silicate species in the inner pore channel.

The design and catalytic performance of molybdenum active sites on an MCM-41 framework for the aerobic oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran

2019 ◽  
Vol 9 (3) ◽  
pp. 811-821 ◽  
Author(s):  
Zhao-Meng Wang ◽  
Li-Juan Liu ◽  
Bo Xiang ◽  
Yue Wang ◽  
Ya-Jing Lyu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Active Sites ◽  
Aerobic Oxidation ◽  
Catalytic Performance ◽  
Mcm 41

The catalytic activity decreases as –(SiO)3Mo(OH)(O) > –(SiO)2Mo(O)2 > –(O)4–MoO.

Nickel (II) and oxovanadium (IV) complexes supported on MCM-41 mesoporous and their application in catalytic selective sulfide and thiol oxidation

2020 ◽  
Vol 23 ◽  
Author(s):  
Mohsen Nikoorazm ◽  
Maryam Khanmoradi ◽  
Masoumeh Sayadian
Keyword(s):  
Catalytic Activity ◽  
Room Temperature ◽  
Sol Gel ◽  
Reaction Times ◽  
Significant Loss ◽  
Spectral Studies ◽  
High Catalytic Activity ◽  
Catalytic Systems ◽  
Solvent Free Conditions ◽  
Mcm 41

Introduction:: MCM-41 was synthesized using the sol-gel method. Then two new transition metal complexes of Nickel (II) and Vanadium (IV), were synthesized by immobilization of adenine (6-aminopurine) into MCM-41 mesoporous. The compounds have been characterized by XRD, TGA, SEM, AAS and FT-IR spectral studies. Using these catalysts provided an efficient and enantioselective procedure for oxidation of sulfides to sulfoxides and oxidative coupling of thiols to their corresponding disulfides using hydrogen peroxide at room temperature. Materials and Methods:: To a solution of sulfide or thiol (1 mmol) and H2O2 (5 mmol), a determined amount of the catalyst was added. The reaction mixture was stirred at room temperature for the specific time under solvent free conditions. The progress of the reaction was monitored by TLC using n-hexane: acetone (8:2). Afterwards, the catalyst was removed from the reaction mixture by centrifugation and, then, washed with dichloromethane in order to give the pure products. Results:: All the products were obtained in excellent yields and short reaction times indicating the high activity of the synthesized catalysts. Besides, the catalysts can be recovered and reused for several runs without significant loss in their catalytic activity. Conclusion:: These catalytic systems furnish the products very quickly with excellent yields and VO-6AP-MCM-41 shows high catalytic activity compared to Ni-6AP-MCM-41.

Synthesis and characterization of highly ordered MCM-41 in an alkali-free system and its catalytic activity

1996 ◽  
Vol 38 (1-2) ◽  
pp. 33-37 ◽  
Author(s):  
Xiu S. Zhao ◽  
Gao Q. Lu ◽  
Graeme J. Millar ◽  
Xin S. Li
Keyword(s):  
Catalytic Activity ◽  
Synthesis And Characterization ◽  
Free System ◽  
Mcm 41
Sign in / Sign up

Export Citation Format

Share Document