Use of Micro- and Nano-ZnO particles as Catalysts for the Microwave-Assisted Polymerization of D,L-lactide

2015 ◽  
Vol 1767 ◽  
pp. 3-9
Author(s):  
Heriberto Rodríguez-Tobías ◽  
Graciela Morales ◽  
Javier Enríquez ◽  
Carlos Espinoza-González ◽  
Daniel Grande
Keyword(s):  
Reaction Time ◽  
Green Synthesis ◽  
Microwave Heating ◽  
Thermal Characterization ◽  
Monomer Conversion ◽  
Medical Applications ◽  
Nano Zno ◽  
Short Reaction Time ◽  
Microwave Assisted ◽  
Zno Particles

ABSTRACTThe use of a catalyst is required to synthesize poly(D,L-lactide) (PLA) and tin (II) 2-ethylhexanoate could be highlighted among them. However, this kind of catalysts can produce bio-dangerous compounds limiting the PLA in medical applications, therefore there is a need to investigate novel bio-safe catalysts. Taking into account this problem, this communication reports the use of micro- and nano-ZnO particles as catalysts for the microwave-assisted polymerization of D,L-lactide. By microwave heating a high monomer conversion (higher than 95%) was achieved in a relatively short reaction time (3 hours). Morphology/size and concentration of ZnO particles presented a strong effect on the production of PLA, star-like microparticles leaded to conversion ca. 25%, well below to the values achieved with the nanoparticles. Furthermore, the formation of a ZnO-PLA hybrid was evidenced by spectroscopic and thermal characterization techniques. The methodology herein developed represents a new pathway for the green synthesis of PLA.

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 An efficient green synthesis of novel 1H-imidazo[1,2-a]imidazole-3-amine and imidazo[2,1-c][1,2,4]triazole-5-amine derivatives via Strecker reaction under controlled microwave heating

2019 ◽  
Vol 8 (1) ◽  
pp. 297-301 ◽  
Author(s):  
Kamal Usef Sadek ◽  
Afaf Mohamed Abdel-Hameed ◽  
Hisham A. Abdelnabi ◽  
Yasser Meleigy
Keyword(s):  
Reaction Time ◽  
Green Synthesis ◽  
Microwave Heating ◽  
Environmentally Friendly ◽  
Aromatic Aldehydes ◽  
One Pot ◽  
Short Reaction Time ◽  
Strecker Reaction ◽  
Benzoyl Cyanide ◽  
High Yields

Abstract A highly efficient multi-component one-pot synthesis of novel 1H-imidazo[1,2-a]imidazole-3-amine and imidazo[2,1-c][1,2,4]triazole-5-amine derivatives has been developed through the reaction of easily available aromatic aldehydes, benzoyl cyanide and either 2-aminoimidazole-4,5-dicarbonitrile or 3-amino-1,2,4-triazole in pyridine under controlled microwave heating. The process is environmentally friendly, is operationally simple, with short reaction time and with high yields.

Preparation and Co (II) Removal of ZnO/Poly-Piperazineamide Nanofiltration Membranes

2017 ◽  
Author(s):  
Xiaoguang Zhang ◽  
Xuexing Chen ◽  
Qingchun Chen ◽  
Zhaolong Deng ◽  
Yan Liu ◽  
...  
Keyword(s):  
Reaction Time ◽  
Monomer Concentration ◽  
Attenuated Total Reflection ◽  
Radioactive Nuclide ◽  
Separation Performance ◽  
Separation Mechanism ◽  
Nanofiltration Membranes ◽  
Terephthaloyl Chloride ◽  
Nano Zno ◽  
Zno Particles

A series of nanofiltration membranes were prepared by interfacial polymerization of piperazine and terephthaloyl chloride on the surface of polyacrylonitrile (PAN) ultrafiltration membranes. ZnO nanoparticles were incorporated in the active separation layer to modify the performances of the membranes. The preparation conditions as the monomer concentration, dosage of nano-ZnO particles and the reaction time on removal of a simulated radioactive nuclide Co (II) were investigated. Fourier transform infrared in attenuated total reflection mode verified the formation of polyamide on the PAN ultrafiltration membrane. The scanning electron microscope images showed that the nano-ZnO particles can homogeneously fixed on the membrane surface. The retention of Co (II) increased with increasing the dosage of nano-ZnO in the range of 0∼0.03 g. Further adding more nano-ZnO, the rejection rate of Co (II) first decreased and then increased. The concentration of piperazine and terephthaloyl chloride showed similar effect on removal of Co (II) ion. 5 minutes polymerization time was sufficient to form an active separation layer on the substrate membrane which changed the separation mechanism from ultrafiltration to nanofiltration. The separation performance of NF3 prepared by the following conditions was optimum: 0.03g nano-ZnO, 0.6 wt% piperazine, 0.5 wt% terephthaloyl chloride, and the reaction time was 15 min. The rejection rates of 1000 mg/L Na2SO4 and Co2+ in CoCl2 solution were 90% and 75% respectively. The Co (II) removal rate can be increased to nearly 90% by using ethylenediaminetetraacetic acid disodium salt. Increasing the operation pressure or the feeding concentration of Co (II) can also improve the performances of the membranes in this experiment.

scholarly journals Green synthesis of 2-aryl-4-phenyl-quınazolıne derıvatives promoted by lactıc acıd

2017 ◽  
Vol 36 (2) ◽  
pp. 223 ◽  
Author(s):  
Belgheis Adrom ◽  
Nourallah Hazeri ◽  
Malek Taher Maghsoodlou ◽  
Mojtaba Lashkari ◽  
Maryam Fatahpour
Keyword(s):  
Lactic Acid ◽  
Reaction Time ◽  
Green Synthesis ◽  
Ammonium Acetate ◽  
Simple Procedure ◽  
Environmentally Benign ◽  
Synthetic Method ◽  
Short Reaction Time ◽  
Quinazoline Derivatives ◽  
Work Up

An environmentally benign three-component synthetic method is described for the construction of 2-aryl-4-phenylquinazoline derivatives from the reaction between aldehydes, ammonium acetate, and 2-aminobenzophenone in the presence of lactic acid in a solvent-less media. The benefits of the reaction were good yields, a simple procedure, simple starting materials short reaction time, easy work-up, and cleaner reaction profiles.

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.

Microwave-assisted regioselective synthesis of acyclic nucleosides through an alkylating reaction with 2-oxa-1,4-butanediol diacetate

2006 ◽  
Vol 84 (5) ◽  
pp. 819-824 ◽  
Author(s):  
Guirong Qu ◽  
Suhui Han ◽  
Zhiguang Zhang ◽  
Mingwei Geng ◽  
Feng Xue
Keyword(s):  
Reaction Time ◽  
Microwave Irradiation ◽  
Regioselective Synthesis ◽  
Environmental Friendliness ◽  
Short Reaction Time ◽  
Microwave Assisted ◽  
Acyclic Nucleosides ◽  
Green Procedure ◽  
Simple Manipulation

An efficient and green procedure for the synthesis of purine acyclic nucleosides through microwave-assisted alkylation of various purine nucleobases with 2-oxa-1,4-butanediol diacetate in the absence of solvent and catalyst is described. The advantages of using this method include its environmental friendliness, simple manipulation, short reaction time, high regioselectivity, and good yields.Key words: acyclic nucleosides, microwave irradiation, regioselectivity, alkylation, 2-oxa-1,4-butanediol diacetate.

Microwave Assisted Envirocat EPZ-10 Catalyzed Multi-component Synthesis of 1-Amidoalkyl-2-naphthols

2021 ◽  
Vol 6 (3) ◽  
pp. 204-210
Author(s):  
Kanchan Joshi-Kulkarni ◽  
Tarulata Chhowala ◽  
Balu Ajalkar
Keyword(s):  
Reaction Time ◽  
Green Synthesis ◽  
Mass Spectroscopy ◽  
Heterogeneous Catalysts ◽  
Catalytic Efficiency ◽  
Solvent Free ◽  
Spectroscopic Methods ◽  
Synthetic Method ◽  
Microwave Assisted ◽  
Solvent Free Reaction

Microwave assisted catalytic efficiency of Envirocat EPZ-10 was explored in solvent free green synthesis of 1-amidoalkyl-2-naphthols by the reaction of aldehyde, 2-naphthol and acetamide. The products formed were characterized by spectroscopic methods such as NMR, IR and mass spectroscopy. The merits of developed synthetic method are use of Envirocat EPZ-10 as eco-friendly, reusable and heterogeneous catalysts, solvent-free reaction, shorter reaction time and easy isolation of product.

Preparation of Nano ZnO Particles by Microwave Assisted Hydrothermal Method and its Toxicity to Microalgae

2014 ◽  
Vol 602-603 ◽  
pp. 38-41 ◽  
Author(s):  
Hong Ying Yu ◽  
Zhi Jiang Dong ◽  
Zhi Qin Chen ◽  
Shan Shan Luo
Keyword(s):  
Hydrothermal Method ◽  
Zinc Nitrate ◽  
Zinc Ions ◽  
Nano Zno ◽  
Microwave Assisted ◽  
Chlorella Sp ◽  
Zno Particles

In this paper, nanocrystalline ZnO particles were prepared feasibly by microwave assisted hydrothermal method with Zinc nitrate and NaOH as start materials. XRD results show the ZnO was crystallized well. The as-received powders are hexagonal platelets of about 20-100 nm in diameter. Toxicity experiments using wastewater microalgae (Chlorella sp.) revealed that the toxicity of ZnO is strongly related with the Zinc ions concentration in water.

Microwave assisted rapid conversion of fructose into 5-HMF over solid acid catalysts

RSC Advances ◽  
2015 ◽  
Vol 5 (128) ◽  
pp. 106053-106060 ◽  
Author(s):  
Jie Wang ◽  
Ting Qu ◽  
Minsi Liang ◽  
Zhenbo Zhao
Keyword(s):  
Reaction Time ◽  
Solid Acid ◽  
Solid Acid Catalysts ◽  
Acid Catalysts ◽  
Short Reaction Time ◽  
Microwave Assisted ◽  
Efficient Conversion ◽  
Rapid Conversion

Microwave assisted efficient conversion of fructose into 5-hydroxymethylfurfural over solid acid catalysts in a very short reaction time.

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