scholarly journals Silica Bonded S-Sulfonic Acid: A Recyclable Catalyst for the Synthesis of Quinoxalines at Room Temperature

Molecules ◽  
2009 ◽  
Vol 14 (5) ◽  
pp. 1915-1926 ◽  
Author(s):  
Khodabakhsh Niknam ◽  
Dariush Saberi ◽  
Maleki Mohagheghnejad
RSC Advances ◽  
2014 ◽  
Vol 4 (32) ◽  
pp. 16589-16596 ◽  
Author(s):  
Mostafa Golshekan ◽  
Shahab Shariati ◽  
Naghi Saadatjoo

Sulfonic acid functionalized mesoporous magnetite nanoparticles as an efficient, heterogeneous and recyclable catalyst for the synthesis of aminonaphtols and β-amino carbonyls. Advantages: good yields, rapid reaction, solvent-free conditions and room temperature.


2017 ◽  
Vol 71 (11) ◽  
pp. 2504-2511 ◽  
Author(s):  
Daniele T. Dias ◽  
Guy Lopes ◽  
Tales Ferreira ◽  
Ivanir L. Oliveira ◽  
Caroline D. Rosa

The Nafion membranes are widely used in electrochemical applications such as fuel cells, chlor-alkali cells, and actuators–sensors. In this work, the thermal-optical characterization of Nafion in acid form was performed by photoacoustic spectroscopy, thermogravimetry, and differential scanning calorimetry. In the experimental procedure three distinct hydration levels were considered: (1) pristine membrane (λ ≅ H2O/–SO3H ≅ 5.6); (2) swelling process (λ ≅ 17.4); and (3) drying at controlled room temperature after swelling process (λ ≅ 6.5). The discovered behaviors showed significant irreversible structural changes induced by water retention in the membrane. These structural changes depend on the water population present in the clusters and also affect the directional thermal diffusivity of the membrane irreversibly.


2021 ◽  
Vol 37 (6) ◽  
pp. 1295-1301
Author(s):  
Elmustapha Ennesyry ◽  
Fathallaah Bazi ◽  
Bahija Mounir ◽  
M’hammed Elkouali Elkouali ◽  
Hassan Hannache ◽  
...  

Functionalized alkenes were successfully synthesized via a clean procedure in a short time by using a new recycled heterogeneous catalyst prepared from Moroccan oil shale, this catalyst is characterized by different technics such XRD, BET-BJH, MEB-EDS, and TGA, before it’s has been used in the Knoevenagel condensation between different aldehydes and active methylenes. The results showed that coupling the catalyst with ultrasound irradiations could improve the catalytic system in this transformation by achieving the products in a very short time, the results showed clearly that this catalyst could be considered as excellent recyclable support in Knoevenagel condensation.


2010 ◽  
Vol 28 (4) ◽  
pp. 663-669 ◽  
Author(s):  
Khodabakhsh Niknam ◽  
Mohammad R. Mohammadizadeh ◽  
Salimeh Mirzaee ◽  
Dariush Saberi

RSC Advances ◽  
2020 ◽  
Vol 10 (67) ◽  
pp. 41229-41236
Author(s):  
Jitendra Kumar Yadav ◽  
Priyanka Yadav ◽  
Satish K. Awasthi ◽  
Alka Agarwal

Sulfonic acid functionalized over biguanidine fabricated silica-coated heterogeneous magnetic nanoparticles (NP@SO3H) have been synthesized, well characterized and explored for the first time, as an efficient and recyclable catalyst for N-formylation of primary amines under mild reaction conditions.


Foods ◽  
2019 ◽  
Vol 8 (7) ◽  
pp. 255 ◽  
Author(s):  
Vukoja ◽  
Pichler ◽  
Kopjar

The aim of this work was to assess the effect of a set storage period on the phenolics, anthocyanins, antioxidant activity, color, and texture of three types of jams made from tart cherry. The prepared samples of tart cherry jams were: (1) regular jam; (2) extra jam; and (3) light jam. The samples were stored at room temperature for eight months. Results of the investigated parameters after storage were compared with the results after sample preparations, and between the different jam samples. The light jam had the highest phenolic content and anthocyanin content (3.34 g/kg and 985.52 mg/kg). Consequently, the light jam had the highest antioxidant activity determined by ABTS (2,2'-azinobis(3-ethylbenzothiazoline sulfonic acid)) and DPPH (2,2-diphenyl-1-picrylhydrazil) method. After storage, the highest retention of the phenolics had regular jam and extra jam (85%), while the lowest retention (74%) were found in the light jam. Anthocyanin stability was the highest in the regular jam, then the extra jam (15%), and then the light jam, with retention of 22%, 15%, and 12%, respectively. Color parameters and textural parameters also depended on jam type, as well as on storage conditions. Since the investigated types of jams differed in content of fruit and water, these are the most important factors that cause the change in the retention of phenolics and anthocyanins, as well as a change in color and textural parameters.


RSC Advances ◽  
2015 ◽  
Vol 5 (48) ◽  
pp. 38085-38092 ◽  
Author(s):  
Tahshina Begum ◽  
Manoj Mondal ◽  
Pradip K. Gogoi ◽  
Utpal Bora

A novel Pd@imine-SiO2 catalyst was prepared and found to exhibit excellent catalytic activity in a Suzuki-Miyaura cross-coupling reaction under aqueous media at room temperature.


2018 ◽  
Vol 28 (16) ◽  
pp. 1707369 ◽  
Author(s):  
Tomoki Ogoshi ◽  
Hiromu Tsuchida ◽  
Takahiro Kakuta ◽  
Tada‐aki Yamagishi ◽  
Ai Taema ◽  
...  

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