Editorial

416 KiB

Open AccessEditorial

by Rajender S. Varma

Appl. Sci. 2014, 4(4), 493-497; https://doi.org/10.3390/app4040493 - 29 Sep 2014

Cited by 28 | Viewed by 5967

In the pursuit towards attaining sustainability, arrays of greener pathways are being carved to address the needs of the diverse chemical universe. The evolving area of green and sustainable chemistry envisions minimum hazard as the performance criterion while designing new chemical processes. Green [...] Read more.

In the pursuit towards attaining sustainability, arrays of greener pathways are being carved to address the needs of the diverse chemical universe. The evolving area of green and sustainable chemistry envisions minimum hazard as the performance criterion while designing new chemical processes. Green Chemistry is defined as "the utilization of a set of principles that reduces or eliminates the use or generation of hazardous substances in the design, manufacture, and application of chemical products" [1]. Sustainable processes are being sought to explore alternatives to conventional chemical syntheses and transformations. Among several thrust areas for achieving this target includes: the utility of alternative feedstocks, preferably from renewable materials or waste from other industries; unconventional efficient reaction conditions and eco-friendly reaction media to accomplish the desired chemical transformations with minimized by-products or waste generation, and ideally avoiding the use of conventional volatile organic solvents, wherever possible. Other avenues for achieving this objective are to explore the generation of efficient catalytic processes, particularly magnetically retrievable nano-catalysts [1,2,3,4]. In addition to greener synthesis, the recyclability and reuse aspects for catalytic systems are extremely significant particularly when it boils down to the use of endangered elements and precious catalysts. Several friendlier applications in catalysis have been advanced via magnetically recoverable and recyclable nano-catalysts for oxidation, reduction, and multi-component condensation reactions [1,2,3,4] and this has made a terrific impact on the development of green chemical pathways [1]. The greener preparation of nanoparticles has been exemplified via the use of vitamins B1, B2, C, and tea [5] and wine polyphenols [6], beet juice [7] and other agricultural residues which function both as reducing and capping agents. This avoids the need to deploy toxic reducing agents, such as borohydrides or hydrazines and empowers simple and aqueous green synthetic methods to produce bulk quantities of nano-catalysts without the requirement for large amounts of insoluble templates [8]. [...] Full article

(This article belongs to the Special Issue Greener and Sustainable Chemistry)

Research

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245 KiB

Open AccessArticle

A Solvent-Free, One-Step, One-Pot Gewald Reaction for Alkyl-aryl Ketones via Mechanochemistry

by William C. Shearouse, Maxwell Z. Shumba and James Mack

Appl. Sci. 2014, 4(2), 171-179; https://doi.org/10.3390/app4020171 - 08 Apr 2014

Cited by 23 | Viewed by 10067

Abstract

Herein, we report on the solvent-free synthesis of 2-aminothiophenes via the Gewald reaction. Utilizing high speed ball milling conditions, we discovered the Gewald reaction can be catalytic in base, and conducted under aerobic conditions. Using thermal heat in tandem with the mixer/mill significantly [...] Read more.

Herein, we report on the solvent-free synthesis of 2-aminothiophenes via the Gewald reaction. Utilizing high speed ball milling conditions, we discovered the Gewald reaction can be catalytic in base, and conducted under aerobic conditions. Using thermal heat in tandem with the mixer/mill significantly increases the rate of reaction. Full article

(This article belongs to the Special Issue Greener and Sustainable Chemistry)

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325 KiB

Open AccessCommunication

Properties of Thermosets Derived from Chemically Modified Triglycerides and Bio-Based Comonomers

by Evan S. Beach, Zheng Cui, Paul T. Anastas, Mingjiang Zhan and Richard P. Wool

Appl. Sci. 2013, 3(4), 684-693; https://doi.org/10.3390/app3040684 - 04 Dec 2013

Cited by 15 | Viewed by 12338

Abstract

A series of materials was prepared by curing acrylated epoxidized soybean oil (AESO) and dibutyl itaconate (DBI) or ethyl cinnamate (EC) comonomers to provide examples of thermosets with a high proportion of bio-based carbon, in accordance with the principles of green chemistry. The [...] Read more.

A series of materials was prepared by curing acrylated epoxidized soybean oil (AESO) and dibutyl itaconate (DBI) or ethyl cinnamate (EC) comonomers to provide examples of thermosets with a high proportion of bio-based carbon, in accordance with the principles of green chemistry. The comonomers, representative of cellulose-derived (DBI) or potentially lignin-derived (EC) raw materials, were tested at levels of 25%, 33%, and 50% by mass and the resulting products were characterized by infrared spectroscopy, thermogravimetric analysis, and dynamic mechanical analysis. Both DBI and EC were incorporated into the thermosets to a high extent (>90%) at all concentrations tested. The AESO-DBI and AESO-EC blends showed substantial degradation at 390–400 °C, similar to pure AESO. Glass transition temperatures decreased as comonomer content increased; the highest T_g of 41.4 °C was observed for AESO-EC (3:1) and the lowest T_g of 1.4 °C was observed for AESO-DBI (1:1). Accordingly, at 30 °C the storage modulus values were highest for AESO-EC (3:1, 37.0 MPa) and lowest for AESO-DBI (1:1, 1.5 MPa). Full article

(This article belongs to the Special Issue Greener and Sustainable Chemistry)

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1258 KiB

Open AccessCommunication

Aqueous Microwave-Assisted Solid-Phase Synthesis Using Boc-Amino Acid Nanoparticles

by Keiko Hojo, Natsuki Shinozaki, Yoshimi Nozawa, Yoshinobu Fukumori and Hideki Ichikawa

Appl. Sci. 2013, 3(3), 614-623; https://doi.org/10.3390/app3030614 - 24 Jul 2013

Cited by 17 | Viewed by 13765

Abstract

We have previously developed water-based microwave (MW)-assisted peptide synthesis using Fmoc-amino acid nanopaticles. It is an organic solvent-free, environmentally friendly method for peptide synthesis. Here we describe water-based MW-assisted solid-phase synthesis using Boc-amino acid nanoparticles. The microwave irradiation allowed rapid solid-phase reaction of [...] Read more.

We have previously developed water-based microwave (MW)-assisted peptide synthesis using Fmoc-amino acid nanopaticles. It is an organic solvent-free, environmentally friendly method for peptide synthesis. Here we describe water-based MW-assisted solid-phase synthesis using Boc-amino acid nanoparticles. The microwave irradiation allowed rapid solid-phase reaction of nanoparticle reactants on the resin in water. We also demonstrated the syntheses of Leu-enkephalin, Tyr-Gly-Gly-Phe-Leu-OH, and difficult sequence model peptide, Val-Ala-Val-Ala-Gly-OH, using our water-based MW-assisted protocol with Boc-amino acid nanoparticles. Full article

(This article belongs to the Special Issue Greener and Sustainable Chemistry)

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705 KiB

Open AccessArticle

Photopolymerization Reactions: On the Way to a Green and Sustainable Chemistry

by Mohamad Ali Tehfe, Fanny Louradour, Jacques Lalevée and Jean-Pierre Fouassier

Appl. Sci. 2013, 3(2), 490-514; https://doi.org/10.3390/app3020490 - 24 Apr 2013

Cited by 157 | Viewed by 12824

Abstract

The present paper reviews some aspects concerned with the development of green technologies in the photopolymerization area: use of visible light sources (Xe and Hg-Xe lamps, diode lasers), soft irradiation conditions (household lamps: halogen lamp, fluorescence bulbs, LED bulbs), sunlight exposure, development of [...] Read more.

The present paper reviews some aspects concerned with the development of green technologies in the photopolymerization area: use of visible light sources (Xe and Hg-Xe lamps, diode lasers), soft irradiation conditions (household lamps: halogen lamp, fluorescence bulbs, LED bulbs), sunlight exposure, development of very efficient photoinitiating systems and use of renewable monomers. The drawbacks/breakthroughs encountered when going on the way of a greener approach are discussed. Examples of recent achievements are presented. Full article

(This article belongs to the Special Issue Greener and Sustainable Chemistry)

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215 KiB

Open AccessArticle

Ultrasonics Promoted Synthesis of 5-(Pyrazol-4-yl)-4,5-Dihydropyrazoles Derivatives

by Jorge Trilleras, Efraín Polo, Jairo Quiroga, Justo Cobo and Manuel Nogueras

Appl. Sci. 2013, 3(2), 457-468; https://doi.org/10.3390/app3020457 - 16 Apr 2013

Cited by 13 | Viewed by 6686

Abstract

A series of new 1,3-diaryl-5-(1-phenyl-3-methyl-5-chloropyrazol-4-yl)-4,5-dihydropyrazole derivatives have been synthesized under sonication conditions in ethanol or methanol/glacial acetic acid mixture (5/1 ratio) with two equivalents of hydrazines and seven kinds of chalcone-like heteroanalogues obtained from 5-chloro-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde. The structures were established on the [...] Read more.

A series of new 1,3-diaryl-5-(1-phenyl-3-methyl-5-chloropyrazol-4-yl)-4,5-dihydropyrazole derivatives have been synthesized under sonication conditions in ethanol or methanol/glacial acetic acid mixture (5/1 ratio) with two equivalents of hydrazines and seven kinds of chalcone-like heteroanalogues obtained from 5-chloro-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde. The structures were established on the basis of NMR, IR, MS and element analysis. This method provides several advantages over current reaction methodologies, including a simple work-up procedure, shorter reaction times (2–20 min) and good yields (65%–80%). Full article

(This article belongs to the Special Issue Greener and Sustainable Chemistry)

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Review

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956 KiB

Open AccessReview

Sustainable Utility of Magnetically Recyclable Nano-Catalysts in Water: Applications in Organic Synthesis

by Manoj B. Gawande, Anuj K. Rathi, Paula S. Branco and Rajender S. Varma

Appl. Sci. 2013, 3(4), 656-674; https://doi.org/10.3390/app3040656 - 25 Oct 2013

Cited by 83 | Viewed by 10861

Abstract

Magnetically recyclable nano-catalysts and their use in aqueous media is a perfect combination for the development of greener sustainable methodologies in organic synthesis. It is well established that magnetically separable nano-catalysts avoid waste of catalysts or reagents and it is possible to recover [...] Read more.

Magnetically recyclable nano-catalysts and their use in aqueous media is a perfect combination for the development of greener sustainable methodologies in organic synthesis. It is well established that magnetically separable nano-catalysts avoid waste of catalysts or reagents and it is possible to recover >95% of catalysts, which is again recyclable for subsequent use. Water is the ideal medium to perform the chemical reactions with magnetically recyclable nano-catalysts, as this combination adds tremendous value to the overall benign reaction process development. In this review, we highlight recent developments inthe use of water and magnetically recyclable nano-catalysts (W-MRNs) for a variety of organic reactions namely hydrogenation, condensation, oxidation, and Suzuki–Miyaura cross-coupling reactions, among others. Full article

(This article belongs to the Special Issue Greener and Sustainable Chemistry)

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Graphical abstract

220 KiB

Open AccessReview

Glycerol: A promising Green Solvent and Reducing Agent for Metal-Catalyzed Transfer Hydrogenation Reactions and Nanoparticles Formation

by Alba E. Díaz-Álvarez and Victorio Cadierno

Appl. Sci. 2013, 3(1), 55-69; https://doi.org/10.3390/app3010055 - 23 Jan 2013

Cited by 106 | Viewed by 19892

Abstract

Glycerol is a non-toxic, non-hazardous, non-volatile, biodegradable, and recyclable liquid that is generated as a byproduct in the manufacture of biodiesel fuel from vegetable oils. Due to its easy availability, along with its unique combination of physical and chemical properties, glycerol has recently [...] Read more.

Glycerol is a non-toxic, non-hazardous, non-volatile, biodegradable, and recyclable liquid that is generated as a byproduct in the manufacture of biodiesel fuel from vegetable oils. Due to its easy availability, along with its unique combination of physical and chemical properties, glycerol has recently emerged as an economically appealing and safe solvent for organic synthesis. Recent works have also demonstrated that glycerol can be used as a hydrogen source in metal-catalyzed transfer hydrogenation of organic compounds, such as aldehydes, ketones, olefins and nitroarenes. Herein, the advances reached in this emerging field are reviewed. The utility of glycerol as solvent and reducing agent for the generation of metal nanoparticles is also briefly discussed. Full article

(This article belongs to the Special Issue Greener and Sustainable Chemistry)

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