Fe3O4@MCM@ZrCI2: A Practical Magnetic Mesoporous Zirconium-Based Nanocomposite as a Reusable Catalyst for the Synthesis of Spirooxindoles

2021 ◽  
Vol 21 (11) ◽  
pp. 5765-5775
Author(s):  
Reyhaneh Pourhasan-Kisomi ◽  
Mostafa Golshekan ◽  
Farhad Shirini
Keyword(s):  
Efficient Method ◽  
Spiro Compounds ◽  
Reusable Catalyst ◽  
Catalytic Role ◽  
Work Up ◽  
Mcm 41

In the present study, we aimed to investigate the catalytic role of the newly reported MCM-41 -based nanocomposite in which the low acidity of this mesoporous moiety was favourably improved via the stabilization of zirconium nanoparticles and was magnetized to make a facile work-up procedure as an applicable and efficient method. The prepared Fe3O4@MCM-41 @ZrCI2 nanocomposite was successfully characterized using different analyses and then it was favourably exploited for the synthesis of spirooxindoles as the most prominent spiro compounds. As predicted, Fe3O4@MCM- 41 @ZrCI2 showed considerable efficiency in the promotion of the studied reaction.

Catalytic Role of Cu Sites of Cu/MCM-41 in Phenol Hydroxylation

Langmuir ◽  
2010 ◽  
Vol 26 (2) ◽  
pp. 1362-1371 ◽  
Author(s):  
Guoying Zhang ◽  
Jinlin Long ◽  
Xuxu Wang ◽  
Zizhong Zhang ◽  
Wenxin Dai ◽  
...  
Keyword(s):  
Phenol Hydroxylation ◽  
Catalytic Role ◽  
Mcm 41

scholarly journals Simple and efficient synthesis of 2,2′-arylmethylenebis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) derivatives

2019 ◽  
Vol 150 (12) ◽  
pp. 2021-2023 ◽  
Author(s):  
Ágnes Magyar ◽  
Zoltán Hell
Keyword(s):  
Efficient Method ◽  
Molecular Sieves ◽  
Reusable Catalyst ◽  
Efficient Synthesis ◽  
Reaction Conditions ◽  
High Yields ◽  
Work Up

Abstract A simple and efficient method for the synthesis of 2,2′-arylmethylenebis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) derivatives using 4 Å molecular sieves as catalyst is described. This approach offers several advantages such as high yields, mild reaction conditions, easily accessible, and reusable catalyst, and simple work-up procedure. Graphic abstract

scholarly journals Flammable gases produced by TiO2 nanoparticles under magnetic stirring in water

Friction ◽  
2021 ◽  
Author(s):  
Pengcheng Li ◽  
Chongyang Tang ◽  
Xiangheng Xiao ◽  
Yanmin Jia ◽  
Wanping Chen
Keyword(s):  
Tio2 Nanoparticles ◽  
Quartz Glass ◽  
Dye Degradation ◽  
Mechanical Energy ◽  
Chemical Energy ◽  
Magnetic Stirring ◽  
Catalytic Role ◽  
Nanostructured Semiconductors

AbstractThe friction between nanomaterials and Teflon magnetic stirring rods has recently drawn much attention for its role in dye degradation by magnetic stirring in dark. Presently the friction between TiO2 nanoparticles and magnetic stirring rods in water has been deliberately enhanced and explored. As much as 1.00 g TiO2 nanoparticles were dispersed in 50 mL water in 100 mL quartz glass reactor, which got gas-closed with about 50 mL air and a Teflon magnetic stirring rod in it. The suspension in the reactor was magnetically stirred in dark. Flammable gases of 22.00 ppm CO, 2.45 ppm CH4, and 0.75 ppm H2 were surprisingly observed after 50 h of magnetic stirring. For reference, only 1.78 ppm CO, 2.17 ppm CH4, and 0.33 ppm H2 were obtained after the same time of magnetic stirring without TiO2 nanoparticles. Four magnetic stirring rods were simultaneously employed to further enhance the stirring, and as much as 30.04 ppm CO, 2.61 ppm CH4, and 8.98 ppm H2 were produced after 50 h of magnetic stirring. A mechanism for the catalytic role of TiO2 nanoparticles in producing the flammable gases is established, in which mechanical energy is absorbed through friction by TiO2 nanoparticles and converted into chemical energy for the reduction of CO2 and H2O. This finding clearly demonstrates a great potential for nanostructured semiconductors to utilize mechanical energy through friction for the production of flammable gases.

scholarly journals Catalytic role of histidine 147 in Escherichia coli thymidylate synthase

1989 ◽  
Vol 264 (32) ◽  
pp. 19132-19137
Author(s):  
I K Dev ◽  
B B Yates ◽  
J Atashi ◽  
W S Dallas
Keyword(s):  
Escherichia Coli ◽  
Thymidylate Synthase ◽  
Catalytic Role

scholarly journals General practitioner use of D-dimer in suspected venous thromboembolism: historical cohort study in one geographical region in the Netherlands

BMJ Open ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. e026846 ◽  
Author(s):  
Angel M R Schols ◽  
Eline Meijs ◽  
Geert-Jan Dinant ◽  
Henri E J H Stoffers ◽  
Mariëlle M E Krekels ◽  
...  
Keyword(s):  
Cohort Study ◽  
General Practitioner ◽  
Clinical Assessment ◽  
Geographical Region ◽  
Historical Cohort ◽  
Diagnostic Work ◽  
Work Up ◽  
Diagnostic Work Up ◽  
D Dimer

ObjectivesTo investigate how many general practitioner (GP)-referred venous thromboembolic events (VTEs) are diagnosed during 1 year in one geographical region and to investigate the (urgent) referral pathway of VTE diagnoses, including the role of laboratory D-dimer testing.DesignHistorical cohort study.SettingGP patients of 47 general practices in a demarcated geographical region of 161 503 inhabitants in the Netherlands.ParticipantsWe analysed all 895 primary care patients in whom either the GP determined a D-dimer value or who had a diagnostic work-up for suspected VTE in a non-academic hospital during 2015.Primary and secondary outcome measuresThe primary outcomes of this study were the total number of VTEs per year and the diagnostic pathways—including the role of GP determined D-dimer testing—of patients urgently referred to secondary care for suspected VTE. Additionally, we explored the use of an age-adjusted D-dimer cut-off.ResultsThe annual VTE incidence was 0.9 per 1000 inhabitants. GPs annually ordered 5.1 D-dimer tests per 1000 inhabitants. Of 470 urgently GP-referred patients, 31.3% had a VTE. Of those urgently referred based on clinical assessment only (without D-dimer testing), 73.8% (96/130) had a VTE; based on clinical assessment and laboratory D-dimer testing yielded 15.0% (51/340) VTE. Applying age-adjusted D-dimer cut-offs to all patients aged 50 years or older resulted in a reduction of positive D-dimer results from 97.9% to 79.4%, without missing any VTE.ConclusionsAlthough D-dimer testing contributes to the diagnostic work-up of VTE, GPs have a high detection rate for VTE in patients who they urgently refer to secondary care based on clinical assessment only.

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