Microwave-assisted solution polycondensation of l-lactic acid using a Dean–Stark apparatus for a non-thermal microwave polymerization effect induced by the electric field

2014 ◽  
Vol 5 (18) ◽  
pp. 5283-5288 ◽  
Author(s):  
Shinji Yamada ◽  
Akinori Takasu ◽  
Sadatsugu Takayama ◽  
Kazuhiko Kawamura
Keyword(s):  
Lactic Acid ◽  
Electric Field ◽  
Microwave Power ◽  
Microwave Assisted ◽  
Microwave Effect ◽  
Microwave Polymerization ◽  
Solution Polycondensation

The solution polycondensation of l-lactic acid (l-LA) in xylene catalyzed by Sc(OTf)3 was examined using a Dean–Stark apparatus under various microwave power conditions (100–400 W). The results indicate the existence of a non-thermal microwave effect induced by an electric field.

scholarly journals Microwave Assisted Alkaline Pretreatment of Algae Waste in the Production of Cellulosic Bioethanol

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5891
Author(s):  
Rocío Maceiras ◽  
Víctor Alfonsín ◽  
Luis Seguí ◽  
Juan F. González
Keyword(s):  
Microwave Power ◽  
Reducing Sugars ◽  
Irradiation Time ◽  
Alkaline Pretreatment ◽  
Liquid Ratio ◽  
Fermentation Efficiency ◽  
Microwave Assisted ◽  
Microwave Effect ◽  
Solid Liquid ◽  
Bioethanol Yield

Biomass pretreatment has an important role in the production of cellulosic bioethanol. In this study, the effectiveness of microwave assisted alkaline pretreatment of algae waste was analysed. After pretreatment, the product was hydrolysed using sulphuric acid. The effects of microwave power, irradiating time, solid–liquid ratio and NaOH concentration were examined. Under the best conditions, the fermentable sugars were converted to cellulosic bioethanol using Saccharomyces Cerevisiae with a bioethanol yield of 1.93 ± 0.01 g/g and a fermentation efficiency of 40.4%. The reducing sugars concentration was 30% higher than that obtained from conventional hydrolysis without pretreatment. The obtained results suggest that microwave assisted alkaline pretreatment is effective in improving the production of cellulosic bioethanol of algae waste compared to that without microwave effect. Considering energy consumption, low microwave power and short microwave irradiation time are favourable for this pretreatment.

scholarly journals Effect of Microwave Power on Performance of Microwave-Assisted Spark Ignition under CO2-Diluted Condition

2021 ◽  
Vol 692 (2) ◽  
pp. 022001
Author(s):  
Xinhua Zhang ◽  
Zhaowen Wang ◽  
Huimin Wu ◽  
Chaohui Liu ◽  
Zhihao Wang ◽  
...  
Keyword(s):  
Microwave Power ◽  
Spark Ignition ◽  
Microwave Assisted

Microwave-Assisted Leaching Vanadium from Stone Coal

2011 ◽  
Vol 189-193 ◽  
pp. 3916-3919 ◽  
Author(s):  
Hong Zhou Ma ◽  
Xin Zhe Lan ◽  
Yao Ning Wang ◽  
Yu Hong Tian
Keyword(s):  
Sulfuric Acid ◽  
Microwave Power ◽  
Orthogonal Design ◽  
Chemical Constituents ◽  
Influence Factors ◽  
Sulfate Solution ◽  
Leaching Rate ◽  
Stone Coal ◽  
Microwave Assisted ◽  
Design Experiments

Technological process of microwave-assisted leaching of vanadium with sulfate solution has been defined on the base of phase and chemical constituents of stone coal. The influence factors such as content of sulfuric acid, microwave power, and leaching time were studied on leaching rate of vanadium from the stone coal. One element experiments and orthogonal design experiments are carried out to achieve optimized parameters. The experimental results showed that the leaching rate of vanadium was improved by the change of influence factors at some range. The single leaching rate of vanadium reached 80.9% under the optimal conditions of sulfuric acid content of 12%, microwave power 539w,leaching time of 2h.

Effect of Static High Electric Field Pre-Treatment on Microwave-Assisted Drying of Potato Slices

2013 ◽  
Vol 31 (16) ◽  
pp. 1960-1968 ◽  
Author(s):  
Ashutosh Singh ◽  
Gopu Raveendran Nair ◽  
Jamshid Rahimi ◽  
Yvan Gariepy ◽  
Vijaya Raghavan
Keyword(s):  
Electric Field ◽  
High Electric Field ◽  
Microwave Assisted ◽  
Pre Treatment ◽  
Potato Slices

Microwave Assisted Synthesis of Schiff Bases: A Green Approach

2012 ◽  
Vol 10 (1) ◽  
Author(s):  
Mousumi Chakraborty ◽  
Sanjay Baweja ◽  
Sunita Bhagat ◽  
TejpalSingh Chundawat
Keyword(s):  
Microwave Irradiation ◽  
Microwave Power ◽  
Mass Spectra ◽  
Molar Ratio ◽  
Microwave Assisted Synthesis ◽  
Schiff’S Bases ◽  
Microwave Assisted ◽  
Green Approach ◽  
Schiff's Bases ◽  
Effects Of Temperature

Abstract In the present study Schiff’s bases are synthesized by the conventional as well as by microwave irradiation. Excellent yield within short reaction time is obtained using microwave irradiation along with other advantages like mild reaction condition, non-hazardous and safer environmental conditions. The effects of temperature, reactant molar ratio, and microwave power variation on yield are observed. Mathematical model has been developed using matlab software to obtain the yield as a function of microwave power. Kinetic study of the reaction has also been attempted. Schiff’s bases structures are confirmed by IR, 1HNMR, Mass Spectra and elemental analysis.

scholarly journals Effects of Ultrasonic-Microwave-Assisted Technology on Hordein Extraction from Barley and Optimization of Process Parameters Using Response Surface Methodology

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Xiao Guan ◽  
Lv Li ◽  
Jing Liu ◽  
Sen Li
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Microwave Power ◽  
Process Intensification ◽  
Extraction Yield ◽  
Extraction Time ◽  
Quadratic Model ◽  
Ultrasonic Power ◽  
Microwave Assisted ◽  
The Difference

We investigated the process intensification of ultrasonic-microwave-assisted technology for hordein extraction from barley. Response surface methodology was utilized to optimize the extraction conditions and to analyze the interaction between four selected variables: temperature, microwave power, ultrasonic power, and extraction time. The validated extraction yield of hordein reached 8.84% at 78°C, microwave power 298 W, and ultrasonic power 690 W after 20 min as optimum conditions. Compared with traditional water-bath extraction (4.7%), the ultrasonic-microwave-assisted technology effectively increased the hordein extraction yield and shortened the extraction time. According to the obtained quadratic model (R2 = 0.9457), ultrasonic power and extraction time were the first two significant factors. However, temperature limited the effects of other factors during extraction. SDS-PAGE and scanning electron microscopy were used to identify the hordein extract and to clarify the difference between the two hordein fractions extracted with new and traditional methods, respectively. Ultrasonic-microwave-assisted technology provided a new way to improve hordein extraction yield from barley and could be a good candidate for industrial application of process intensification.

scholarly journals Microwave-assisted extraction of non-polar compounds from pistachio hull and characterization of extracts

2018 ◽  
Vol 69 (3) ◽  
pp. 260 ◽  
Author(s):  
H. N. Özbek ◽  
D. Koçak Yanık ◽  
S. Fadıloğlu ◽  
H. Keskin Çavdar ◽  
F. Göğüş
Keyword(s):  
Microwave Power ◽  
Polar Compounds ◽  
Good Alternative ◽  
Tocopherol Content ◽  
Extraction Time ◽  
Total Phenolic ◽  
Microwave Assisted Extraction ◽  
Solid Ratio ◽  
Microwave Assisted ◽  
Assisted Extraction

Soxhlet and microwave assisted extraction (MAE) methods were used to obtain non-polar compounds from pistachio hull. MAE parameters (liquid to solid ratio, microwave power, and extraction time) were studied to obtain maximum extraction yield. The optimal conditions were found to be liquid to solid ratio of 15:1 (v/w), microwave power of 250 W and extraction time of 12.5 min. The extraction yields were 9.81 and 9.50% for MAE and Soxhlet methods, respectively. The total phenolic content, antioxidant activity and tocopherol content of the extract obtained by MAE was found to be significantly higher than those of the Soxhlet extract (p < 0.05). The results showed that the extract contained α-tocopherols (567.65 mg/kg) and oleic acid (48.46%) as the major tocopherols and fatty acids. These findings propose that hull extracts can be considered as a good source of natural bioactive compounds and MAE can be a good alternative to the traditional Soxhlet method.

scholarly journals Extraction of Phytosterol Concentration in Different Legume Pods by Using Microwave-Assisted Hydrodistillation

2019 ◽  
Vol 19 (3) ◽  
pp. 796
Author(s):  
Noormazlinah Noormazlinah ◽  
Norlaili Hashim ◽  
Abdurahman Hamid Nour ◽  
Mimi Sakinah Abdul Munaim ◽  
Maria Pilar Almajano ◽  
...  
Keyword(s):  
Bioactive Compounds ◽  
Microwave Power ◽  
Ethanol Concentration ◽  
Irradiation Time ◽  
Optimal Conditions ◽  
Solvent Concentration ◽  
Visible Spectroscopy ◽  
Optimum System ◽  
Microwave Assisted ◽  
Extraction Parameters

The traditional ways in the extraction of bioactive compounds using conventional methods are disadvantageous from both economic and environmental perspectives. In this, the potential of microwave-assisted hydrodistillation conditions for extraction of phytosterol from legume pods was investigated. Salkowski test performed on the legume pod has shown the reddish brown in all sample which confirmed the presence of phytosterol qualitatively. Liebermann-Burchard procedure and ultraviolet-visible spectroscopy (UV-Vis) apparatus were used to study the concentration of phytosterol at different extraction parameters which are temperature (25–80 °C), solvent concentration (50–100% v/v), irradiation time (1–10 min) and microwave power (400–800 W). The optimal conditions for highest yield of extract (0.219 mg/L) were obtained at a microwave power of 600 W, the irradiation time of 6 min, and ethanol concentration of 75% v/v. Results obtained in this study have shown the capability of microwave-assisted hydrodistillation in the extraction of phytosterol from legume pod. Further works are nevertheless required to provide a deeper understanding of the mechanisms involved to facilitate the development of an optimum system applicable to the industry.

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