Microwave Assisted Synthesis of 5-hydroxymethylfurfural Using Mild Reaction Conditions

2017 ◽  
Vol 68 (3) ◽  
pp. 435-438 ◽  
Author(s):  
Adina Ionuta Gavrila ◽  
Ioana Asofiei ◽  
Adrian Trifan ◽  
Petre Chipurici ◽  
Edina Rusen
Keyword(s):  
Reaction Time ◽  
Conventional Method ◽  
Industrial Development ◽  
High Performance ◽  
Heterogeneous Catalysts ◽  
Microwave Assisted Synthesis ◽  
Reaction Conditions ◽  
Microwave Assisted ◽  
Catalyst Temperature ◽  
Exchange Resins

5-Hydroxymethylfurfural (5-HMF) is an important platform molecules, being a green precursor for a variety of high performance fuels and valuable chemicals. The production of 5-HMF from fructose under microwave-assisted heating conditions by varying different parameters (catalyst, temperature, stirring rate and reaction time) was studied. Microwave assisted synthesis leads to a shorter reaction time (40 min versus 150 min for conventional method) and the energy consumption is lower compared with the conventional method. Homogeneous and heterogeneous catalysts were tested. Although homogeneous catalysis produced the highest conversion of fructose to 5-HMF, ion exchange resins are preferable for industrial development and the best results were obtained for Dowex resin.

scholarly journals Microwave Assisted Synthesis of 1,5-Benzothiazepines Using Greener Reaction Medium

2019 ◽  
Vol 31 (5) ◽  
pp. 993-996 ◽  
Author(s):  
Sanjay S. Kotalwar ◽  
Amol D. Kale ◽  
Ram B. Kohire ◽  
Vasant B. Jagrut
Keyword(s):  
Reaction Time ◽  
Microwave Irradiation ◽  
Reaction Medium ◽  
Microwave Assisted Synthesis ◽  
Reaction Conditions ◽  
Renewable Sources ◽  
Microwave Assisted ◽  
High Yields

An efficient and eco-friendly synthesis of 1,5-benzothiazepines has been developed by the reaction of various 2-propen-1-ones with 2-aminothiophenol using microwave irradiation in greener reaction medium, glycerol. The clean reaction conditions, shorter reaction time, high yields and non-toxic, biodegradable reaction medium manufactured from renewable sources are unique features of this method.

scholarly journals Microwave-Assisted Synthesis of Isopropylβ-(3,4-Dihydroxyphenyl)-α-hydroxypropanoate

2013 ◽  
Vol 2013 ◽  
pp. 1-7
Author(s):  
Qun-Zheng Zhang ◽  
Xue-Feng Tian ◽  
Guan-Le Du ◽  
Qing Pan ◽  
Yi Wang ◽  
...  
Keyword(s):  
Reaction Time ◽  
Microwave Heating ◽  
Orthogonal Design ◽  
Power Level ◽  
Conventional Heating ◽  
Microwave Assisted Synthesis ◽  
Reaction Conditions ◽  
Microwave Assisted ◽  
Clemmensen Reduction ◽  
Microwave Power Level

Using microwave irradiation heating, isopropylβ-(3,4-dihydroxyphenyl)-α-hydroxypropanoate was synthesised from 3,4-dihydroxybenzaldehyde and acetylglycine through the formation of 2-methyl-4-(3,4-acetoxybenzylene)oxazol-5-ones,α-acetylamino-β-(3,4-diacetoxyphenyl)acrylic acid, andβ-(3,4-dihydroxyphenyl)pyruvic acid followed by Clemmensen reduction and esterification. The reaction conditions in terms of operating parameters were optimised by using an orthogonal design of experiment (ODOE) approach, including reaction temperature, reaction time, and microwave power level. Compared with conventional heating, the reaction time was significantly reduced for all reactions and the product yields were increased (except for the third-step reaction) under microwave heating conditions. The most remarkable microwave enhancement was found in the step of isopropylβ-(3,4-dihydroxyphenyl)-α-hydroxypropanoate production where the reaction time was reduced from 10 hrs (conventional heating) to 25 mins (microwave heating) whilst the yield was increased from 75.6% to 87.1%, respectively.

Size-Controlled Microwave-Assisted Synthesis of Water-Dispersible Cd(Se,S) Quantum Dots for Potential Biological Applications

2015 ◽  
Vol 1784 ◽  
Author(s):  
E. Calderón-Ortiz ◽  
S. Bailón-Ruiz ◽  
L. Alamo-Nole ◽  
J. Rodriguez-Orengo ◽  
O. Perales-Perez
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Reaction Time ◽  
Reaction Temperature ◽  
Quantum Confinement Effect ◽  
Reactive Oxygen Species Generation ◽  
Size Control ◽  
Average Crystallite Size ◽  
Microwave Assisted Synthesis ◽  
Microwave Assisted

ABSTRACTNanomedicine is fostering significant advances in the development of platforms for early detection and treatment of diseases. Nanoparticles (NPs) like quantum dots (QDs) exhibit size-dependent optical properties for light-driven technologies, which might become important in bio-imaging, sensing and photo-dynamic therapy (PDT) applications. The present research addresses the synthesis of water-stable Cd-based QDs via a Microwave-Assisted synthesis approach using cadmium sulfate salt, and thioglycolic acid as Cd- and S-precursors, respectively. Selenide ions were available by reductive leaching of metallic Selenium in Sodium bisulfite solution. The size control and the tunability of the optical properties were achieved by a suitable control of the reaction temperature (in the 140°C- 190°C range) and reaction time (10 minutes-40 minutes). X-ray diffraction analyses suggested the development of a CdSe,S face cubic centered structure; the broadening of the diffraction peaks indicated the presence of very small nanocrystals in the samples. The average crystallite size was estimated at 5.50 nm ± 1.17nm and 3.72 nm ± 0.04 nm, for nanoparticles synthesized at 180°C after 40 minutes or 10 minutes of reaction, respectively. HRTEM images confirmed the crystalline nature and the small size of the synthesized nanocrystals. In turn, the exciton was red-shifted from 461nm to 549 nm when the reaction temperature was prolonged from 140°C to 190 °C, suggesting the crystal growth. The corresponding band gap values were approximately 2.2 eV, confirming the quantum confinement effect (bulk value 1.74eV). This red shift was also evidenced in PL measurements where the main emission peak was shifted from 507 nm to 564 nm when the samples were excited at 420 nm. A narrow size-tunable emission also was supported by the full width at half maximum (∼ 45 nm) for the synthesized nanocrystals. The reactive oxygen species generation capability of as-synthesized QDs was also investigated. The correlation between the particle size and the generation of (ROS) by the degradation of methylene blue was evident with a reduction of MB concentration from 10μM to 7.5μM and 6.7μM after 15 minutes of UV irradiation for reaction time of 10 min. and 40 min. respectively. No additional degradation was noticed after 60 minutes of irradiation.

scholarly journals Microwave assisted synthesis of five membered nitrogen heterocycles

RSC Advances ◽  
2020 ◽  
Vol 10 (59) ◽  
pp. 36031-36041
Author(s):  
Gopinadh Meera ◽  
K. R. Rohit ◽  
Salim Saranya ◽  
Gopinathan Anilkumar
Keyword(s):  
Reaction Time ◽  
Nitrogen Heterocycles ◽  
Product Formation ◽  
Microwave Assisted Synthesis ◽  
Short Reaction Time ◽  
Microwave Assisted ◽  
High Yields

Microwave assisted synthesis of N-heterocycles with short reaction time, high yields and high product purities along with a decrease in the rate of by-product formation.

scholarly journals Microwave Assisted One Pot Synthesis of 3,4-Dihydropyrano[c]chromene Derivatives using [Emim]OH Ionic Liquid as Novel Catalyst

2019 ◽  
Vol 31 (4) ◽  
pp. 829-833
Author(s):  
D.S. Bhagat ◽  
S.G. Pande ◽  
M.V. Katariya ◽  
R.P. Pawar ◽  
P.S. Kendrekar
Keyword(s):  
Ionic Liquid ◽  
Reaction Time ◽  
High Yield ◽  
Reaction Conditions ◽  
One Pot ◽  
Short Reaction Time ◽  
Aryl Aldehydes ◽  
Microwave Assisted ◽  
Novel Catalyst ◽  
Work Up

One-pot efficient protocol to the synthesis of 2-amino-5-oxo-4,5-dihydropyrano(3,2-c)chromene-3-carbonitrile derivatives via condensation of various aryl aldehydes, dicyanomethane and 4-hydroxycoumarin in presence of Emim hydroxide as an excellent homogeneous liquid catalyst. The key advantages of this methodology are mild reaction conditions, novel catalyst, short reaction time, eco-friendly, easy work-up procedure and high yield of isolation of derivatives.

A Convenient One-Pot and Rapid Microwave-Assisted Synthesis of Biologically Active s-Triazolo[3,4-b][1,3,4]Thiadiazine and s-Triazolo[3,4-b][1,3,4]Thiadiazole Nanoarchitectonics

2020 ◽  
Vol 20 (5) ◽  
pp. 2917-2929
Author(s):  
Ahmed F. M. EL-Mahdy ◽  
Hassan A. H. EL-Sherief ◽  
Zeinab A. Hozien ◽  
Shiao-Wei Kuo
Keyword(s):  
Acetic Acid ◽  
Sulfuric Acid ◽  
Reaction Time ◽  
Catalytic Amount ◽  
Biologically Active ◽  
Microwave Assisted Synthesis ◽  
One Pot ◽  
Microwave Assisted ◽  
Work Up ◽  
Temperature Time

A rapid and efficient one-pot protocol has been developed for the synthesis of s-triazolo[3,4-b][1,3,4]thiadiazine and s-triazolo[3,4-b][1,3,4]thiadiazole nanoarchitectonics through the reaction of s-triazoles with ketones and nitriles in acetic acid containing a catalytic amount of sulfuric acid under microwave irradiation in excellent yields. With this catalytic reaction, the cheap sulfuric acid as well as other acids were examined as catalysts and the highly toxic and irritating haloketones and halonitriles were avoided to form. The effects of microwave power, temperature, time, solvent and catalyst were examined. This method achieved a better performance; e.g., higher yields, shorter reaction time and easier work-up as compared to other conventional methods. Therefore, the proposed method will be readily applicable to the synthesis of biologically important compounds containing s-triazolo[3,4-b][1,3,4]thiadiazine and s-triazolo[3,4-b][1,3,4]thiadiazole framework.

Microwave assisted syntheses of solvent-based colloidal sols of tailored ceria nanoparticles

2009 ◽  
Vol 1170 ◽  
Author(s):  
Olivier J.C. Poncelet ◽  
Jouhannaud J. ◽  
Chaumont D.
Keyword(s):  
High Performance ◽  
Mixed Oxides ◽  
Diesel Oil ◽  
Toxic Chemicals ◽  
Exhaust Emission ◽  
Microwave Assisted Synthesis ◽  
Ceria Nanoparticles ◽  
Nanosized Particles ◽  
Exhaust Gases ◽  
Microwave Assisted

AbstractMicrowave assisted syntheses of stable solvent based colloidal sols of tailored ceria nanoparticles Olivier Poncelet*, Julien Jouhannaud*, Denis Chaumont** *CEA Liten DTNM/L2T , 17 rue des Martyrs F-38054 Grenoble Cedex9, France **Institut Carnot Bourgogne (ICB), UMR5209 CNRS, Facult� des Sciences Mirande, Universit� de Bourgogne, 9 Av. Alain Savary, BP 47870, F-21078 Dijon Cedex The pressure of environmental laws in many advanced countries becoming more restricting year after year, it is asked to automobile companies to strongly control the carburant consumption of cars that they put on the market and also to eliminate toxic chemicals coming from exhaust emission gases. This is particularly true for diesel oil which is particularly efficient in terms of carburant consumption but known to release toxic chemicals in exhaust gases. Among the materials able to solve these concerns, ceria (CeO2) is a choice catalyst because it can work in two different ways first as an oxygen store by release of oxygen in the presence of reductives gases (CnHn and CO), and also by removing oxygen by interaction with oxidising species (NOx), leaving finally in exhaust gases H2O, CO2 and N2. To be efficient ceria has to be used under nanoparticle form directly added in the diesel oil. The surface developed by the nanoparticles due to their small size positively influence the catalytic properties (both oxidation and reduction step) in terms of kinetic, so the ignition delay time for nanosized particles in the combustion chamber of diesel motors fits well with the high performance diesel motor characteristics. The true challenge is to be able to prepare stable solvent based sols of crystalline ceria nanoparticles which could be used without plugging the injection nozzles. We present various synthetic ways to produce ceria nanoparticles in water followed by their surface modification allowing stable colloidal sols in organic medium to be designed. We emphasize more particularly the microwave assisted synthesis which by enhancing nucleation of the nanosized particles versus growth of nanoparticles allows very narrow sized distribution of nanoparticles to be obtained. Moreover in terms of synthetic processes, microwave assisted syntheses allow to strongly reduced the synthetic time without compromise in terms of cristallinity (TEM and XRD). Surface modifications of the nanoparticles have been monitored by FT-IR, FT-Raman, while their sizes have been monitored by DLS (differential light scattering) from water to solvents suspension proving the efficiency of ether carboxylic acids as surface modifiers. Finally we will show preliminary results on the microwave assisted syntheses of mixed oxides materials (CeZrOx) and the way to design organic based sols of nanoparticles.

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