Microwave-assisted alkali hydrolysis for cellulose isolation from wheat straw: Influence of reaction conditions and non-thermal effects of microwave

2021 ◽  
Vol 253 ◽  
pp. 117170 ◽  
Author(s):  
Qi Liu ◽  
Wen-Qing He ◽  
Mario Aguedo ◽  
Xu Xia ◽  
Wen-Bo Bai ◽  
...  
Keyword(s):  
Wheat Straw ◽  
Thermal Effects ◽  
Reaction Conditions ◽  
Microwave Assisted ◽  
Alkali Hydrolysis

scholarly journals Microwave-Assisted Asinger Synthesis of Thiazolines

2020 ◽  
Vol 3 (1) ◽  
pp. 27
Author(s):  
Raúl Eduardo Gordillo-Cruz ◽  
Liliana Gonzalez-Reyes ◽  
Milton Coporo-Reyes ◽  
Nieves Zavala-Segovia ◽  
Bernardo A. Frontana-Uribe ◽  
...  
Keyword(s):  
Microwave Irradiation ◽  
Reaction Times ◽  
Reaction Conditions ◽  
Microwave Assisted

An array of 2,4-disubstituted thiazolines was obtained through Asinger reaction approach from the straightforward treatment of diverse aldehydes/ketones with 1-mercaptopropan-2-one, in the presence of NH3 assisted by microwave irradiation, displaying similar and sometimes higher yields, as well as shorter reaction times that traditional Asinger reaction conditions at room and lower temperatures.

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 Heating Reactions of N-Acetylglucosamine (GlcNAc) in Sulfolane as a Method Generating 1,6-Anhydrosugars Consisting of Amino Monosaccharide Backbones

Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 1944
Author(s):  
Harumi Kaga ◽  
Masaru Enomoto ◽  
Hiroki Shimizu ◽  
Izuru Nagashima ◽  
Keigo Matsuda ◽  
...  
Keyword(s):  
Optimal Condition ◽  
General Feature ◽  
Time Course ◽  
High Efficiency ◽  
Raw Materials ◽  
Reaction Conditions ◽  
Microwave Assisted ◽  
High Potentials ◽  
Course Changes

The microwave-assisted heating reaction of N-acetyl glucosamine (GlcNAc) in sulfolane is described. The reaction produces two major products that are assignable to 1,6-anhydro-2-acetamido-2-deoxy-β-d-glucopyranose (AGPNAc) and 1,6-anhydro-2-acetamido-2-deoxy-β-d-glucofuranose (AGFNAc). In order to reveal a general feature of the system, the 3, 5, and 10 min reactions were performed at 140, 160, 180, 200, and 220 °C to clarify the time course changes in the conversion of GlcNAc and the yields of the two produced 1,6-anhydrosugars. Temperature is a crucial factor that significantly affects the conversion of GlcNAc. The yields of AGPNAc and AGFNAc are also drastically changed depending on the reaction conditions. The 5-min reaction at 200 °C is shown to be the optimal condition to generate the 1,6-anhydrosugars with a high efficiency in which AGPNAc and AGFNAc are produced in the yields of 21% and 44%, respectively. Consequently, the microwave-assisted heating reaction of GlcNAc in sulfolane is shown to be a simple and promising pathway to generate 1,6-anhydrosugars consisting of amino monosaccharide backbones, which have high potentials as raw materials leading to biological oligosaccharides and biomimetic polysaccharides.

Probing the Reactivity of 2,4-Dichlorofuro[3,4-d]pyrimidin-7-one: A Versatile and Underexploited Scaffold to Generate Substituted or Fused Pyrimidine Derivatives

Synlett ◽  
2019 ◽  
Vol 30 (17) ◽  
pp. 2010-2014
Author(s):  
Paolo Vincetti ◽  
Gabriele Costantino ◽  
Maria Grazia Martina ◽  
Marco Radi
Keyword(s):  
Chemical Reactivity ◽  
Pyrimidine Derivatives ◽  
Reaction Conditions ◽  
One Pot ◽  
Microwave Assisted ◽  
Set Up

Herein, we describe the results of our investigation on the chemical reactivity and versatility of a poorly explored scaffold: 2,4-dichlorofuro[3,4-d]pyrimidin-7-one (3). Highly functionalized pyrimidines can be obtained with a divergent approach by reacting the key intermediate 3 with different amine nucleophiles under carefully controlled reaction conditions. The set-up of a microwave-assisted one-pot, two- or three-step protocol to rapidly generate 2,4,5,6-tetrasubstituted or fused pyrimidines is also reported.

scholarly journals Effects of Pretreatment Methods of Wheat Straw on Adsorption of Cd(II) from Waterlogged Paddy Soil

2019 ◽  
Vol 16 (2) ◽  
pp. 205 ◽  
Author(s):  
Mengjie Wu ◽  
Hongyu Liu ◽  
Chunping Yang
Keyword(s):  
Wheat Straw ◽  
Paddy Soil ◽  
Morphological Changes ◽  
Ethanol Solution ◽  
Acid Oxidation ◽  
Organic Carbon Content ◽  
Microwave Assisted ◽  
Dynamic Variations ◽  
Behavior Study ◽  
Effective Removal

Two types of pretreatment categories, namely microwave-assisted alkalization and microwave-assisted acid oxidation, were used to synthesize novel wheat straw adsorbents for the effective removal of Cd(II) in simulated waterlogged paddy soil. A systematic adsorption behavior study, including adsorption kinetics and adsorption isotherms was conducted. Results showed that wheat straw pretreated by microwave-assisted soaking of NaOH and ethanol solution obtained the highest Cd(II) removal efficiency of 96.4% at a reaction temperature of 25 ℃, pH of 7.0, initial Cd(II) concentration of 50 mg/L, and adsorbent/adsorbate ratio of 10 g/L. Sequential extraction experiment was carried out to analyze the changes of different of Cd(II) in soil, the aim of which was to study the mobility of Cd(II) and then evaluate the toxicity that Cd(II) might bring to plants. A 60-day incubation was performed to investigate the dynamic variations of soil pH and dissolved organic carbon content over incubation time. Characterization analyses revealed the morphological changes of wheat straw adsorbents, which suggested that those pretreatment methods were of significance. This study provided an environmentally friendly way to reuse agricultural wastes and remedy Cd(II) contaminated soil.

scholarly journals Microwave-assisted functionalization of the Aurivillius phase Bi2SrTa2O9: diol grafting and amine insertion vs. alcohol grafting

2018 ◽  
Vol 9 (35) ◽  
pp. 7104-7114 ◽  
Author(s):  
Yanhui Wang ◽  
Maria Nikolopoulou ◽  
Emilie Delahaye ◽  
Cédric Leuvrey ◽  
Fabrice Leroux ◽  
...  
Keyword(s):  
Amino Alcohols ◽  
Aurivillius Phase ◽  
Reaction Conditions ◽  
Microwave Assisted

The microwave-assisted functionalization of an Aurivillius phase is investigated towards various molecules – alcohols, diols and amino-alcohols – and the preferential reactivity of the various moieties is studied as a function of the reaction conditions.

scholarly journals Microwave Assisted Three Component Reaction Conditions to Obtain New Thiazolidinones with Different Heterocyclic Skeletons

Proceedings ◽  
2019 ◽  
Vol 41 (1) ◽  
pp. 38
Author(s):  
Fernando J. Lorenzo ◽  
Romina A. Ocampo ◽  
Sandra D. Mandolesi
Keyword(s):  
Microwave Irradiation ◽  
Thioglycolic Acid ◽  
Aldehyde Group ◽  
Green Solvent ◽  
Reaction Products ◽  
Reaction Conditions ◽  
One Pot ◽  
Microwave Assisted ◽  
Three Component Reaction ◽  
The One

We present here a new proposal for the “one pot” generation of new 4-thiazolidinones (9a–e) through a multicomponent reaction under microwave irradiation conditions, using aromatic and heteroaromatic amines (8a–e), absolute ethanol as a “green” solvent and modifying the aldehyde group in the glycosidic residue, synthesized from D-mannitol. The study is focused in the variation of the irradiation times and the concentration of thioglycolic acid in order to study the possibility of controlling the structure and/or stereochemistry of the products formed in the reaction. Thiazolidinones 9a–d were obtained with a 69–82% The generation of the corresponding reaction products were monitored by TLC and CG-MS, taking reaction aliquots. The conditions reaction proved to be chemoselective depending on the excess of acid and irradiation times.

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.

scholarly journals Aroylhydrazone Schiff Base Derived Cu(II) and V(V) Complexes: Efficient Catalysts towards Neat Microwave-Assisted Oxidation of Alcohols

2020 ◽  
Vol 21 (8) ◽  
pp. 2832
Author(s):  
Manas Sutradhar ◽  
Tannistha Roy Barman ◽  
Armando J. L. Pombeiro ◽  
Luísa M. D. R. S. Martins
Keyword(s):  
Schiff Base ◽  
Aliphatic Alcohol ◽  
Cinnamyl Alcohol ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
Benzyl Alcohols ◽  
X Ray ◽  
Microwave Assisted ◽  
Tert Butyl Hydroperoxide ◽  
Oxidation Of Alcohols

A new hexa-nuclear Cu(II) complex [Cu3(μ2-1κNO2,2κNO2-L)(μ-Cl)2(Cl)(MeOH)(DMF)2]2 (1), where H4L = N′1,N′2-bis(2-hydroxybenzylidene)oxalohydrazide, was synthesized and fully characterized by IR spectroscopy, ESI-MS, elemental analysis, and single crystal X-ray diffraction. Complex 1 and the dinuclear oxidovanadium(V) one [{VO(OEt)(EtOH)}2(1κNO2,2κNO2-L)]·2H2O (2) were used as catalyst precursors for the neat oxidation of primary (cinnamyl alcohol) and secondary (1-phenyl ethanol, benzhydrol) benzyl alcohols and of the secondary aliphatic alcohol cyclohexanol, under microwave irradiation using tert-butyl hydroperoxide (TBHP) as oxidant. Oxidations proceed via radical mechanisms. The copper(II) compound 1 exhibited higher catalytic activity than the vanadium(V) complex 2 for all the tested alcohol substrates. The highest conversion was found for 1-phenylethanol, yielding 95.3% of acetophenone in the presence of 1 and in solvent and promoter-free conditions. This new Cu(II) complex was found to exhibit higher activity under milder reaction conditions than the reported aroylhydrazone Cu(II) analogues.

Comparison of Conventional and Microwave Heating for Evaluation of Microwave Effects

2016 ◽  
Vol 69 (8) ◽  
pp. 865 ◽  
Author(s):  
Péter Bana ◽  
István Greiner
Keyword(s):  
Temperature Measurement ◽  
Microwave Heating ◽  
Organic Synthesis ◽  
Convenient Method ◽  
Thermal Effects ◽  
Fibre Optic ◽  
Organic Transformations ◽  
Microwave Assisted ◽  
Microwave Reactor ◽  
Microwave Effects

In microwave-assisted organic synthesis, the question of microwave effects is still debated. Proper examination of these hypothesized phenomena is encumbered by some specific features of microwave heating. We devise a convenient method to eliminate most of the irreproducibility observed in microwave-heated organic transformations by thermal conditioning of the microwave reactor cavity. To show the utility of this approach, we investigated a reaction of 2-chloropyridine, in which microwave conditions were shown to be beneficial by previous studies. Using our method to ensure proper reproducibility together with fibre optic temperature measurement, the observed differences were traced back to large hidden thermal differences, while non-thermal effects could not be detected in the comparison experiments.

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