scholarly journals Short-Chain Polyglycerol Production via Microwave-Assisted Solventless Glycerol Polymerization Process Over Lioh-Modified Aluminium Pillared Clay Catalyst: Parametric Study

Processes ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1093
Author(s):  
Muhammad Sajid ◽  
Muhammad Ayoub ◽  
Suzana Yusup ◽  
Bawadi Abdullah ◽  
Rashid Shamsuddin ◽  
...  
Keyword(s):  
Reaction Time ◽  
High Surface ◽  
Pillared Clay ◽  
Short Chain ◽  
Polymerization Process ◽  
Conventional Heating ◽  
Catalyst Loading ◽  
Basal Spacing ◽  
Glycerol Conversion ◽  
Microwave Assisted

In the current study, microwave-assisted glycerol polymerization for short-chain polyglycerol production was conducted unprecedentedly over low-cost catalyst, lithium-modified aluminium pillared clay (Li/AlPC) catalysts without the solvent. The influences of disparate reaction parameters such as the effects of Li loadings (10, 20, 30 wt.%), catalyst loadings (2, 3, 4 wt.%), operating temperatures (200, 220, 240 °C) and operating times (1–4 h) on the glycerol conversions, and polyglycerol yield (particularly for diglycerol and triglycerol), were elucidated. The fresh catalysts were subjected to physicochemical properties evaluation via characterization techniques, viz. N2 physisorption, XRD, SEM, NH3-TPD and CO2-TPD. In comparison, 20 wt.% Li/AlPC demonstrated the best performance under non-conventional heating, credited to its outstanding textural properties (an increase of basal spacing to 21 Ȧ, high surface area of 95.48 m2/g, total basicity of 34.48 mmol/g and average pore diameter of 19.21 nm). Within the studied ranges, the highest glycerol conversion (98.85%) and polyglycerol yield (90.46%) were achieved when catalyst loading of 3 wt.%, reaction temperature of 220 °C and reaction time of 3 h were adopted. The results obtained also anticipated the higher energy efficiency of microwave-assisted polymerization than conventional technique (>8 h), as the reaction time for the former technology was shorter to attain the highest product yield. The study performed could potentially conduce the wise utilization of surplus glycerol generated from the biodiesel industry.

Comparison of Conventional and Microwave Synthesis of Phenyl-1H-pyrazoles and Phenyl-1H-pyrazoles-4-carboxylic Acid Derivatives

2021 ◽  
Vol 18 ◽  
Author(s):  
Antônio S. Machado ◽  
Flávio S. de Carvalho ◽  
Rayssa B.P. Mouraa ◽  
Lorrayne S. Chaves ◽  
Luciano M. Lião ◽  
...  
Keyword(s):  
Reaction Time ◽  
Carboxylic Acid ◽  
Pyrazole Ring ◽  
Conventional Heating ◽  
Pharmacological Activities ◽  
1H And 13C Nmr ◽  
Microwave Assisted ◽  
Attractive Option ◽  
Work Up ◽  
Better Than

Background: Molecules containing the pyrazole subunit considered that privileged scaffolds are of high importance due to their broad spectrum of pharmacological activities. For this reason, a method that is more efficient needs to be developed for the preparation of pyrazole derivatives. Objective: The purpose of this study was the optimisation of the conventional synthesis of the pyrazole ring and the oxidation of phenyl-1H-pyrazole-4-carbaldehyde to phenyl-1H-pyrazole-4-carboxylic acid through Microwave-Assisted Organic Synthesis (MAOS). Method: We performed a comparison between conventional synthesis and conventional synthesis with microwave heating using the synthesis of pyrazole ring described by Finar and Godfrey and, for the oxidation of phenyl-1H-pyrazole-4-carbaldehyde, the method described by Shriner and Kleiderer was used. Results: MAOS reduces the reaction time to obtain all compounds compared to conventional heating. At a temperature of 60°C, 5 minutes of reaction time, and power of 50W, the yield of phenyl-1H-pyrazoles (3a-m) compounds was in the range of 91 - 98% using MAOS, which is better than conventional heating (73 - 90%, 75ºC, 2 hours). An improvement in the yield for the oxidation reaction was also achieved with MAOS. The compounds (5a-m) were obtained with yields ranging from 62 - 92% (80ºC, 2 minutes, 150W), while the yields with conventional heating were in the range of 48 - 85% (80ºC, 1 hour). The 26 compounds were achieved through an easy work-up procedure with no chromatographic separation. The pure products were characterised by the spectral data obtained from IR, MS, 1H and 13C NMR or HSQC/HMBC techniques. Conclusion: The advantages of MAOS include short reaction time and increased yield, due to which it is an attractive option for the synthesis of pyrazole compounds.

Microwave-assisted Al-substituted Tobermorite Synthesis

2000 ◽  
Vol 15 (4) ◽  
pp. 850-853 ◽  
Author(s):  
Michihiro Miyake ◽  
Shigeto Niiya ◽  
Motohide Matsuda
Keyword(s):  
Reaction Time ◽  
Hydrothermal Synthesis ◽  
Microwave Heating ◽  
Conventional Heating ◽  
Crystallization Time ◽  
Short Reaction Time ◽  
Microwave Assisted

The effect of microwave heating on the hydrothermal synthesis of Al-substituted tobermorite and the removal characteristics of resulting materials were examined and compared with the effect of conventional heating. The microwave heating reduced the crystallization time of Al-substituted tobermorite—i.e., Al-substituted tobermorite was synthesized within 80 min at around 140 °C—and produced smaller crystallites than the conventional heating. The minute crystallites were found to promote the removal characteristics for Cs+ ions in short reaction time.

scholarly journals A Green Synthesis of a Novel Calix[4]Resorcinarene from 7-Hydroxycitronellal Using Microwave Irradiation

2018 ◽  
Vol 18 (1) ◽  
pp. 53
Author(s):  
Ratnaningsih Eko Sardjono ◽  
Iqbal Musthapa ◽  
Iis Rosliana ◽  
Fitri Khoerunnisa ◽  
Galuh Yuliani
Keyword(s):  
Energy Consumption ◽  
Reaction Time ◽  
Microwave Irradiation ◽  
Irradiation Time ◽  
Microwave Oven ◽  
Conventional Heating ◽  
Heating Method ◽  
Microwave Assisted ◽  
Domestic Microwave Oven ◽  
Waste Production

A new versatile macromolecule cyclic C-3,7-dimethyl-7-hydroxycalix[4]resorcinarene (CDHHK4R) has been synthesized from a fragrance agent, 7-hydroxycitronellal, via microwave irradiation. The reaction utilized a domestic microwave oven at various irradiation time and power to yield an optimum condition. As a comparison, the conventional heating method was also employed for the synthesis of the same calix[4]resorcinarene. Compared to the conventional method, microwave-assisted reaction effectively reduced the reaction time, the amount of energy consumption and the waste production. It is found that the synthesis of CDHHK4R by microwave irradiation yielded 77.55% of product, higher than by conventional heating which was only 62.17%.

Nano Copper Catalyzed Microwave Assisted Coupling of Benzene Boronic Acids with Thiophenols

2019 ◽  
Vol 16 (6) ◽  
pp. 491-494
Author(s):  
Dinesh S. Gavhane ◽  
Aniket P. Sarkate ◽  
Kshipra S. Karnik ◽  
Shritesh D. Jagtap ◽  
Sajed H. Ansari ◽  
...  
Keyword(s):  
Reaction Time ◽  
Microwave Irradiation ◽  
Bond Formation ◽  
Boronic Acids ◽  
Conventional Heating ◽  
Microwave Technique ◽  
Microwave Assisted ◽  
Measurable Amount ◽  
Ligand Free

A proficient, microwave mediated methodology using CuFe2O4 nanoparticle as the catalyst for S-arylation of substituted benzene boronic acids with thiophenol has been developed. In this method, the substituted thioethers were easily obtained through a C-S bond formation using microwave irradiation technique as well as conventional heating in the presence of CuFe2O4 nanoparticles with modest to excellent yields with the less reaction time. The ligand free microwave technique helped in the preparation of substituted thioethers in measurable amount within 10 mins. The same results were obtained with conventional heating in 12h. The reported method is economically efficient and an alternative to the initial existing method for the preparation of substituted thioethers.

THE EFFECT OF CONVENTIONAL AND MICROWAVE HEATING TECHNIQUES ON TRANSESTERIFICATION OF WASTE COOKING OIL TO BIODIESEL

2016 ◽  
Vol 78 (8-3) ◽  
Author(s):  
Mohd Johari Kamaruddin ◽  
Nurulsurusiah Mohamad ◽  
Umi Aisah Asli ◽  
Muhammad Abbas Ahmad Zaini ◽  
Kamarizan Kidam ◽  
...  
Keyword(s):  
Microwave Heating ◽  
Processing Parameters ◽  
Waste Cooking Oil ◽  
Green Technology ◽  
Conventional Heating ◽  
Molar Ratio ◽  
Catalyst Loading ◽  
Thermal Heating ◽  
Microwave Assisted ◽  
Cooking Oil

This research is focused on the effect of processing parameters such as molar ratio of sample to solvent (1:3-1:15), catalyst loading (0.5-2.5 wt %), temperature (40-80 °C) and time of reaction (5-180 min) on the transesterification yield of waste cooking oil (WCO) in conventional thermal heating and microwave heating techniques. The analysis carried out revealed that the microwave assisted transesterification produced a comparable yield to conventional heating transesterification with ~5 times faster in heating up the reaction mixture to a reaction temperature and reduced ~90% of the reaction time required. This study concludes that microwave assisted transesterification, which is a green technology, may have great potential in reducing the processing time compared to conventional thermal heating transesterification.

scholarly journals Microwave-Assisted Synthesis of 3,4-Dihydropyrimidin-2(1H)-Ones Using Acid-Functionalized Mesoporous Polymer

2021 ◽  
Author(s):  
Bishwajit Changmai ◽  
Kalyani Rajkumari ◽  
diparjun das ◽  
Samuel Lalthazuala Rokhum
Keyword(s):  
Microwave Irradiation ◽  
Condensation Reaction ◽  
High Surface ◽  
High Surface Area ◽  
Analytical Techniques ◽  
Conventional Heating ◽  
Molar Ratio ◽  
Catalyst Loading ◽  
Microwave Assisted Synthesis ◽  
Mesoporous Polymer

Synthesis and application of acid-functionalized mesoporous polymer catalyst for the synthesis of 3,4-Dihydropyrimidin-2(1H)-ones via Biginelli condensation reaction under microwave irradiation is investigated. Several analytical techniques such as FT-IR, BET, TEM, SEM and EDX were employed to characterize the synthesized polymeric catalyst. High acidity (1.15 mmol g-1 ), high surface area (90.44 m2 g -1 ) and mesoporous nature of the catalyst effectively promoted the synthesis of 3,4-Dihydropyrimidin-2(1H)-ones. Microwave irradiation shows higher yield (89-98 %) as compared to conventional heating (15-25 % yield) under our optimized reaction conditions such as 1:1:1.2 molar ratio of aldehyde/ethylacetoacetate/urea, catalyst loading of 6 wt.% (with respect to aldehyde), the temperature of 80 °C and microwave power of 50 W. The synthesized Biginelli products were fully characterized by 1H and 13C NMR. The reusability of the catalyst was investigated up to 5 successive cycles and it showed great stability towards the synthesis of 3,4-Dihydropyrimidin-2(1H)-ones without any significant depreciation in yields.

scholarly journals Synthesis of glycerol carbonate from dimethyl carbonate and glycerol using CaO derived from eggshells

2018 ◽  
Vol 192 ◽  
pp. 03045 ◽  
Author(s):  
Wanichaya Praikaew ◽  
Worapon Kiatkittipong ◽  
Kunlanan Kiatkittipong ◽  
Navadol Laosiripojana ◽  
Navin Viriya-empikul ◽  
...  
Keyword(s):  
Reaction Time ◽  
Reaction Temperature ◽  
Dimethyl Carbonate ◽  
Value Added ◽  
Cost Effective ◽  
Molar Ratio ◽  
Catalyst Loading ◽  
Glycerol Carbonate ◽  
Glycerol Conversion ◽  
Carbonate Production

Waste eggshell is proposed as a highly active catalyst for glycerol carbonate production from dimethyl carbonate (DMC) and glycerol. The effect of reaction temperature, reaction time and catalyst loading on the reaction performance were investigated in order to find a suitable operating condition. CaO derived from waste eggshell exhibits catalytic activity comparable to commercial CaO. By using CaO eggshell, glycerol conversion of 96% can be achieved within 90 min of reaction time under 2.5:1 feed molar ratio of DMC to glycerol, 0.08 mole ratio of CaO to glycerol and reaction temperature of 60°C. The catalyst was examined by XRD, TGA/DSC, SEM, N2 adsorption-desorption and Hammett indicators method. Utilization of eggshell as a catalyst for glycerol carbonate production not only provides a cost-effective and value-added of waste eggshell as a green catalyst, but also decrease amount of waste and its treatment cost which is ecologically friendly.

scholarly journals Microwave-Assisted Synthesis of Some Quinoxaline-Incorporated Schiff Bases and Their Biological Evaluation

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
L. Achutha ◽  
R. Parameshwar ◽  
B. Madhava Reddy ◽  
V. Harinadha Babu
Keyword(s):  
Reaction Time ◽  
Microwave Irradiation ◽  
Schiff Bases ◽  
Biological Evaluation ◽  
Conventional Heating ◽  
Microwave Assisted Synthesis ◽  
Microwave Method ◽  
Heating Method ◽  
Chemical Structures ◽  
Microwave Assisted

Quinoxaline-incorporated Schiff bases(4a–j)were synthesized by the condensation of 2-[(3-methylquinoxalin-2-yl)oxy]acetohydrazide(3)with indole-3-carbaldehyde, furfuraldehyde, 5-(4-nitrophenyl)-2-furfuraldehyde, and substituted benzaldehydes under conventional and microwave irradiation methods. The microwave method was found to be remarkably successful with higher yields, less reaction time, and environmentally friendly compared to conventional heating method. The chemical structures of the synthesized compounds have been confirmed by analytical and spectral data. All the compounds have been evaluated for antitubercular and anti-inflammatory activities.

Successive optimisation of waste cooking oil transesterification in a continuous microwave assisted reactor

RSC Advances ◽  
2015 ◽  
Vol 5 (94) ◽  
pp. 76743-76751 ◽  
Author(s):  
M. A. Mohd. Ali ◽  
R. M. Yunus ◽  
C. K. Cheng ◽  
J. Gimbun
Keyword(s):  
Reaction Time ◽  
Waste Cooking Oil ◽  
Catalyst Loading ◽  
Microwave Assisted ◽  
Cooking Oil ◽  
Optimisation Techniques

The successive optimisation techniques successfully reduce the reaction time by 25.5% and catalyst loading by 32% without significantly affecting the biodiesel conversion.

scholarly journals Microwave-Assisted Synthesis of 3,4-Dihydropyrimidin-2(1H)-Ones Using Acid-Functionalized Mesoporous Polymer

2021 ◽  
Author(s):  
Bishwajit Changmai ◽  
Kalyani Rajkumari ◽  
diparjun das ◽  
Samuel Lalthazuala Rokhum
Keyword(s):  
Microwave Irradiation ◽  
Condensation Reaction ◽  
High Surface ◽  
High Surface Area ◽  
Analytical Techniques ◽  
Conventional Heating ◽  
Molar Ratio ◽  
Catalyst Loading ◽  
Microwave Assisted Synthesis ◽  
Mesoporous Polymer

Synthesis and application of acid-functionalized mesoporous polymer catalyst for the synthesis of 3,4-Dihydropyrimidin-2(1H)-ones via Biginelli condensation reaction under microwave irradiation is investigated. Several analytical techniques such as FT-IR, BET, TEM, SEM and EDX were employed to characterize the synthesized polymeric catalyst. High acidity (1.15 mmol g-1 ), high surface area (90.44 m2 g -1 ) and mesoporous nature of the catalyst effectively promoted the synthesis of 3,4-Dihydropyrimidin-2(1H)-ones. Microwave irradiation shows higher yield (89-98 %) as compared to conventional heating (15-25 % yield) under our optimized reaction conditions such as 1:1:1.2 molar ratio of aldehyde/ethylacetoacetate/urea, catalyst loading of 6 wt.% (with respect to aldehyde), the temperature of 80 °C and microwave power of 50 W. The synthesized Biginelli products were fully characterized by 1H and 13C NMR. The reusability of the catalyst was investigated up to 5 successive cycles and it showed great stability towards the synthesis of 3,4-Dihydropyrimidin-2(1H)-ones without any significant depreciation in yields.

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