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Results in Journal Green and Sustainable Chemistry: 206

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Hiromu Okada, Chao Zhao, Yusuke Mizuta, Katsumi Yoshino, Ryuichi Sugimoto
Green and Sustainable Chemistry, Volume 11, pp 9-22; doi:10.4236/gsc.2021.111002

Methyl methacrylate (MMA) was successfully grafted onto cellulose nanofibers (CNFs) at room temperature in an emulsion system using a diethyl(1,10-phenanthroline N1,N10)zinc(II) complex (Phen-DEZ) with oxygen as the radical initiator. The effects of reaction temperature, initiator concentration, and monomer content on the grafting reaction were investigated. The molecular weight of the non-grafted PMMA, which was produced during graft polymerization, was more than 1 million, as determined by size exclusion chromatography. The PMMA-grafted CNFs were analyzed by Fourier transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy, which confirmed the grafting of PMMA on the nanofiber surface. The study presents a strategy for the grafting of high-molecular weight PMMA onto CNFs in an emulsion system using Phen-DEZ and O2.
Helen Olayinka Ogunsuyi, Christiana Aanu Olawale
Green and Sustainable Chemistry, Volume 11, pp 59-71; doi:10.4236/gsc.2021.112006

This study investigated the viability of post-harvested plantain biomass as a promising feedstock for the production of Bioethanol. The properties of the derived bio-ethanol were determined to examine its suitability as a promising and sustainable alternative to petroleum-based ethanol The research revealed that Plantain biomass is made up of Lignocellulosic contents such as extractive, Lignin, cellulose, hemicelluloses, ash and moisture in different proportions. The different parts of the biomass such as the flower, stem and leaves were hydrolyzed using H2SO4. Optimum hydrolysis conditions of 6%w/v acid concentration, 30 min contact time and 80°C working temperature were established for Plantain stem and flower. However, hydrolysis of Plantain leaves was at the best under the experimental conditions of acid concentration (10% w/v), contact time (120 min) and temperature (120°C). The highest yield of the bio-ethanol produced was obtained from Plantain stem biomass with a record of 8.04% followed by Plantain flower with a yield of 7.73% and 757% from Plantain leaves The hydrolyzate was fermented using Baker’s yeast (Saccharomyces cerevisiae) at a room temperature of 25°C and pH of 4.5 for 4 D. The structural determination of the derived bioethanol was conducted using FT-IR analysis and the fuel properties were found to be consistent with those of the conventional ethanol. The SEM analysis conducted on the post hydrolysed biomass confirmed the effectiveness of the hydrolysis scheme adopted as evident on the surface morphology of the biomass. This study confirmed the viability of Plantain biomass as promising feedstock for Bio-ethanol production under the established hydrolysis conditions.
Yutaka Okada, Ryuichi Maeda
Green and Sustainable Chemistry, Volume 11, pp 1-8; doi:10.4236/gsc.2021.111001

Microwave-assisted reactions are an environmentally friendly approach for synthesizing organic compounds. In this study, oximation of acetylferrocene and acetophenone was conducted under both microwave irradiation and conventional heating conditions. Acetylferrocene and acetophenone were subjected to oximation under the two conditions in various solvent mixtures, and the extent of conversion was determined by 1H nuclear magnetic resonance spectroscopy. Microwave irradiation was found to accelerate the rate of oximation of both acetylferrocene and acetophenone. Acceleration of the reaction under microwave irradiation was attributed to the efficient absorption of microwaves by the ferrocene nucleus.
Sujata Mandal, Sreekar B. Marpu, Roxana Hughes, Mohammad A. Omary, Sheldon Q. Shi
Green and Sustainable Chemistry, Volume 11, pp 28-38; doi:10.4236/gsc.2021.111004

A procedure for the green synthesis of silver nanoparticles (AgNPs) using Cannabis sativa (hemp plant) as a stabilizing media was developed and antibacterial activity was tested. Within 30 minutes of heating the mixture of silver nitrate and hemp extract, the formation of silver nanoparticles took place under the complete absence of a chemical reducing or an additional stabilizing agent. The so-formed AgNPs were characterized using different optical spectroscopy and electron microscopy techniques. The initial formation of AgNPs was established from UV-Vis data based on surface plasmon resonance (SPR) of AgNPs at ~417 nm. The exact size, shape, and elemental composition of AgNPs were established from ESEM images and EDS data. The antibacterial activity of these nanoparticles was studied on Gram-positive Staphylococcus aureus, and Gram-negative Escherichia coli following Disk diffusion and Minimum Inhibitory Concentration (MIC) tests. Results showed that the biosynthesis of silver nanoparticles using hemp extract could be a simple,inexpensive, and biocompatible method.
Nurudeen Ishola Mohammed, Nassereldeen Ahmed Kabbashi, Zahangir Alam, Mohamed Elwathig S. Mirghani
Green and Sustainable Chemistry, Volume 11, pp 23-37; doi:10.4236/gsc.2021.111003

Cost of biodiesel is primarily because of factors such as the feedstock, production process and materials. Apparently, the final biodiesel product is a bit expensive compared to fossil diesel fuel. While non-food feedstock of high oil content such as Jatropha curcas has been proposed to reduce the cost due to the feedstock, a promising two-step approach of hydro-esterification can possibly offset the production cost for oil resource with high free fatty acids. Most importantly, optimization of the materials and process is expected to reduce wastage, enhance product purity and generate less wastewater. However, optimizing product generation has been dauntingly elusive because several parameters are needed to be considered holistically. In this study, Response Surface Methodology (RSM) was employed to optimize the yield and conversion of Jatropha biodiesel from J. curcas hydrolysate. An optimum Yield and conversion of 96% was achieved for both responses with an optimum temperature value of 60°C, 4 wt% for catalyst loading for 6 hrs reaction time. Findings imply that optimization study of Jatropha curcas hydrolysate for yield and conversion of fatty acid methyl esters using face centered central composite design of Design Expert 6.0.8 can ensure purity of product, conserve energy and reduce waste generation providing a significant frontier in biodiesel pricing.
Aristide H. W. Nakavoua, Guy Crépin Enoua, Stéphanie Manhan-Iniangas, Pierre Chalard, Gilles Figuérédo
Green and Sustainable Chemistry, Volume 11, pp 49-58; doi:10.4236/gsc.2021.112005

Skin aging is a process most often attributed to UV [1] and also to the use of creams and other cosmetic products low in antioxidant compounds [2]. Photochemically stable pepo Cucurbita oil can be used as an exogenous cosmetic supplement due to its high antioxidant content. Incorporated in an agar, media containing a synthetic melanin solution with added pumpkin oil are subjected to UV light, the aging thus modeled is followed by the measurement of photoresistance values correlated with chemical and spectrophotometric analyses. This study confirms that pumpkin oil is highly effective in protecting the skin, especially the most sensitive skins such as babies’ skin [3] by reinforcing the action of melanin and also that of albinos without melanin. Indeed its SPF (Significant Sun Protection Factor) index estimated during this work is very consistent, i.e. more than 22% of UVB (280 - 315 nm) radiations are suppressed.
Katenta Joseph, Nakiguli Caroline, Mukasa Paul, Ntambi Emmanuel, Joseph Katenta, Caroline Nakiguli, Paul Mukasa, Emmanuel Ntambi
Green and Sustainable Chemistry, Volume 10, pp 91-107; doi:10.4236/gsc.2020.103007

The potential of the Senegal date palm (Phoenix reclinata) seed bio-char to remove chromium (VI) ions from aqueous solutions by adsorption was investigated. Adsorption experiments were performed on the tannery effluent and standard aqueous solutions of chromium (VI) for varying adsorbent doses, contact times, pH, temperatures, and interfering anionic ions by batch mode. Phoenix reclinata seeds (PRS) bio-char was used in the investigation and the residual chromium (VI) was determined using the atomic absorption spectrophotometer (AAS). Results showed that the bio-char removed up to 86% of chromium (VI) ions in the effluent at pH 2. The highest percentage adsorption registered was 97% in an aqueous solution of chromium (VI) at pH 1 and this dropped to less than 10% at pH greater than 2. A general increase in adsorption with the increase in temperature was observed but reduced when the temperature was raised beyond 60°C. The presence of interfering anions caused a reduction in the adsorption of chromium (VI) ions. The adsorption process fitted both Langmuir and Freundlich adsorption models and the maximum adsorption capacity, Qo, was 0.6593 mg/g. Thus, PRS bio-char can therefore be used by industries and institutions like secondary schools to treat effluents that contain chromium (VI).
Kshama Parajuli, Aravind Kumar Sah, Hari Paudyal
Green and Sustainable Chemistry, Volume 10, pp 117-132; doi:10.4236/gsc.2020.104009

Because of various disadvantages of chemical synthesis processes, these days people are attracting towards green synthesis processes as it is devoid of toxic by-products, cost-effective and eco-friendly. In this study, a simple green synthesis method is applied for the synthesis of magnetite (Fe3O4) nanoparticles (MNPs) by co-precipitation of FeCl3·6H2O and FeSO4·7H2O in the molar ratio of 2:1 using Azadirachta indica leaves extract under nitrogen environment. FTIR, XRD, SEM etc. were used to characterize the synthesized MNPs. Batch adsorption experiments were carried out to determine adsorption equilibrium of As(V) as a function of pH, adsorbent dose, contact time and different initial concentrations. Kinetics results were best described by pseudo-second order model with rate constant value 0.0052 g/(mg·min). The equilibrium adsorption isotherm was best fitted with Langmuir adsorption isotherm model. The maximum adsorption capacity was found to be 62.89 mg/g at pH 2. MNPs showed a high affinity for As(V) and avoids filtration for solid-liquid separation, thus it would be employed as a promising material for the removal of As(V) from water.
A. Matin Mohammad, Bhattacharjee Samiran, Aftab Ali Shaikh, Debnath Tapas, Abdul Aziz Mohammed, Mohammad A. Matin, Samiran Bhattacharjee, Tapas Debnath, Mohammed Abdul Aziz
Green and Sustainable Chemistry, Volume 10, pp 39-55; doi:10.4236/gsc.2020.102004

As a substitute for lithium ion batteries, Na chemistry for ion battery systems is promising materials for energy storage applications for the next generation. Herein, the structures, IR and UV-visible spectra of 2-aminoterephthalic acid (H2ATA), disodium 2-aminoterephthalate (Na2ATA), trisodium 2-aminotere-phthalate (Na3ATA) and tetrasodium 2-aminoterephthalate (Na4ATA) have been studied using density functional theory (DFT/B3LYP/6-311++G(d,p)). The theoretical geometric parameters and FTIR results showed very good agreement with the experimental results. Different conformers of Na2ATA, Na3ATA and Na4ATA showed that the binding energy per sodium in Na2ATA, Na3ATA and Na4ATA is -694.94, -543.44 and -407.46 kJ/mol, respectively. The Na3ATA and Na4ATA salts are higher in energy (151.46 and 287.48 kJ/mol, respectively) than Na2ATA, indicating the higher stability of the Na2ATA complex. The calculated binding energy, enthalpy and Gibbs free energy of Na2ATA, Na3ATA and Na4ATA revealed that the compounds are thermodynamically stable. Natural bond orbital (NBO) analysis of Na2ATA, Na3ATA and Na4ATA indicated that the major interaction occurs between the lone pair electrons of the oxygen atom and anti-bonding orbitals of carbon atoms of the two carboxylate ions. UV-visible spectrum of the free H2ATA and its sodium salts Na2ATA, Na3ATA and Na4ATA were performed using the time-dependent density functional theory (TD-DFT) method at the level of B3LYP/6-311++G(d,p). The frontier molecular orbital energetic parameters and global reactivity descriptors revealed that the Na4ATA and Na3ATA complexes exhibited a higher band gap (ΔEgap) and electronegativity (χeV) than Na2ATA.
A. Aldoasri Mohammad, S. Darwish Sawsan, A. Adam Mahmoud, A. Elmarzugi Nagib, M. Ahmed Sayed, Mohammad A. Aldoasri, Sawsan S. Darwish, Mahmoud A. Adam, Nagib A. Elmarzugi, Sayed M. Ahmed
Green and Sustainable Chemistry, Volume 10, pp 72-90; doi:10.4236/gsc.2020.103006

This part of study represents the applied study; which is a continuation of the experimental study that was carried out in part 1 [1]. The experimental study in part 1 focused on evaluation of the effectiveness of Montmorillonite clay, calcium carbonate, and silicon dioxide nanoparticles for enhancing the performances of epoxy adhesives used in re-assembly of archaeological massive limestones. Based on the obtained results in part 1, the choice fell on epoxy-clay nanocomposites as the best re-assembly adhesive material reinforced with Stainless Steel to conduct the applied study project. The current applied study that represents a big project was carried out on 3 archaeological pharaonic massive limestones discovered separately in Ain Shams (Heliopolis) archaeological area in Egypt. The methodology included an accurate archaeological study, followed by analytical, and then the restoration and reassembly process. Firstly; in order to prove whether these artifacts are complementary to each other or not, then with a view to re-assembly and conserving these artifacts in the form of one stone block to be ready for museum display. Referred to the comprehensive archaeological and analytical study of the mentioned archeological stones, the results confirmed that, these stone pieces, in the original were one piece, therefore, it is possible to regrouping again to become one block complementary to each other, and this is what was done in this study.
Yutaka Okada, Arisa Fujitsu
Green and Sustainable Chemistry, Volume 10, pp 18-23; doi:10.4236/gsc.2020.101002

The effect of microwave irradiation on the intermolecular and intramolecular Friedel-Crafts acylation of aromatic compounds was investigated. Microwave irradiation had no effect on the intermolecular reaction but had an accelerating effect on the intramolecular reaction. This enhanced intramolecular reactivity that was attributed to the high probability of close proximity between the reaction sites.
Mohammad A. Aldosari, Sawsan S. Darwish, Mahmoud A. Adam, Nagib A. Elmarzugi, Sayed M. Ahmed
Green and Sustainable Chemistry, Volume 10, pp 24-38; doi:10.4236/gsc.2020.101003

Massive limestones were used in construction of ancient Egyptian tombs, temples, obelisks and other sculptures. These stones are always exposed to physico-mechanical deterioration and destructive forces, leading to partial or total collapse. The task of reassembling this type of artifacts represents a big challenge for the conservators. Recently, the researchers are turning to new technologies to improve the properties of traditional adhesive materials and techniques used in re-assembly of broken massive stones. The epoxy resins are used extensively in stone conservation and re-assembly of broken stones because of their outstanding mechanical properties. The adding of nanoparticles to polymeric adhesives at low percentages may lead to substantial improvements of their mechanical performances in structural joints and massive objects. The aim of this study is to evaluate the effectiveness of montmorillonite clay, calcium carbonate, and silicon dioxide nanoparticles for enhancing the performances of epoxy adhesives used in re-assembly of archaeological massive limestones. Scanning electron microscopy (SEM) was employed in order to investigate the morphology of the prepared nanocomposites, and the distribution of nanoparticles inside the composites. Artificial aging, tensile, compressive, and elongation strength tests were used to evaluate the efficiency of epoxy-nanocomposites. The results showed that the epoxy-clay nanocomposites exhibited superior tensile, compressive, and elongation strength, in addition to improving the mechanical properties of stone joints.
Shoko Suzuki, Hiroyuki Ito, Motoyoshi Noike, Shinji Ishizuka, Risehiro Nonaka, Kenji Funaki, Takeshi Kodama, Shujiro Sakaki, Tomomichi Nishino, Mina Ito, et al.
Green and Sustainable Chemistry, Volume 10, pp 1-17; doi:10.4236/gsc.2020.101001

Recently, the development of environmentally friendly syntheses of imine derivatives, which were attracting great attention for their reactivity and structure in various fields, progressed rapidly because the concept of green chemistry had deeply penetrated into society. In our previous work, we had reported new synthetic methods of imine derivatives using some active amines under solvent- and catalyst-free reaction conditions. This synthetic reaction proceeded smoothly and target compounds were obtained in excellent yields. In this system, when less reactive amines were used as substrates, the synthetic reaction was not finished in the short reaction time, and the corresponding compounds were given in moderate yields. In order to solve this point, we tried to improve the reaction conditions of this method. Through this improvement, it was found that pure target compounds could be obtained in excellent yields by using 1.1 equivalents of less reactive amines to aldehydes and extending the reaction time compared with our previous work. In this paper, we will introduce the detail of this study, and also report the result of the investigation of the reaction property by computational chemistry.
Michael Bong Alang, Maurice Kor Ndikontar, T. Ndifon Peter, Alang Michael Bong, Ndikontar Maurice Kor, Peter T. Ndifon
Green and Sustainable Chemistry, Volume 10, pp 57-71; doi:10.4236/gsc.2020.103005

This paper reports a field survey undertaken to determine the availability of raw material for palm kernel oil commercial production for industrial applications. Both industrial and artisanal wastes from palm kernel oil production were also surveyed as raw material (palm kernel seeds) for green energy production. Results of the field study show that 22% of palm kernel seeds (which represents tons of waste) resulting from palm oil processing plants are dumped while at the artisanal level, 80% of palm kernel seed waste is dumped. Analysis of field study data shows that large amounts of waste palm kernel seeds are available to enable large scale production of palm kernel oil (PKO) for desirable industrial applications in green energy production. The paper also reports on the physical and chemical properties of Cameroon palm kernel oil (PKO). Palm kernel oil was extracted using mechanical press and solvent extraction. The palm kernel oil (PKO) from Cameroon was analyzed by standard physico-chemical methods. Results of the physical measurements show a specific gravity of PKO of 0.92 kg/L, viscosity of 26.03 cSt and at 5.93 cSt at 40°C and 100°C respectively, viscosity index of 185, pour point of 20°C, cloud point of 29°C, flash point of 200°C, aniline point of 105°F, diesel index of 23, cetane number of 27 and ASTM (American Standards for Testing and Materials) color of less than 2.5. Results of chemical analyses showed an acid value of 17.95 mg KOH/g, free fatty acid (FFA) content of 8.98 mg KOH/g, iodine value of 2.10 mg I2/g, peroxide value of 2.10 meq/kg, ester value of 123.0 mg KOH/g, hydroxyl value of 93.4 mg OH/g, saponification value of 140.95 mg KOH/g and a sulfur content of 0.016% w/v, signifying low sulfur content. Gas chromatography-mass spectrometry (GC-MS) showed the palm kernel oil to be predominantly made up of glycerides of various fatty acids with higher proportions of C12 to C16 fatty acid residues. Cameroon PKO therefore has a broad spectrum of industrial applications by virtue of its rich physical and chemical properties.
Baktygul Abylaeva, Tilebaldy Abdulazizov, Zamira Sandybaeva, Zhypargul Abdullaeva, Ernis Bepiev, Zakhro Akhmedova
Green and Sustainable Chemistry, Volume 10, pp 109-116; doi:10.4236/gsc.2020.104008

This article is investigating the preparation of essential oil from the ether-containing plants of Juniper (Juniperus) and spruce (Picea) leaves by using the simple water distillation equipment. This water distillation method forms an essential oil with water vapor from plants of Juniper (Juniperus) and spruce (Picea) leaves based on Dalton’s law of partial pressure, applicable for plants containing a large amount of ether oil where distillation temperature is not affecting product quality. Obtained essential oils are widely used in medicine, perfumery, cosmetics, and food industry. In addition, these essential oils possess different activities including antimicrobial, antiviral, and anti-inflammatory, which have different effects such as adaptogenic, antidepressive, disinfection, and wound healing, diuretic, and antipyretic.
Topwe Milongwe Mwene-Mbeja, Céline Vaneeckhaute
Green and Sustainable Chemistry, Volume 9, pp 11-25; doi:10.4236/gsc.2019.91002

The interest of this conference is agricultural, environmental, bioenergetics, and sanitary. In that context, domestic, agricultural and industrial environments produce organic waste, which needs to be collected, selected, stored and recycled properly in order to avoid environmental pollution and promote agriculture. The green Industry proposed involves the conversion of natural, non-toxic organic waste in order to efficiently produce organic fertilizers for agriculture. These types of fertilizers from biological origin are suitable because they are not toxic for human and the environment. Enzymatic reactions described in this presentation concern mainly the hydrolysis of proteins, sugars and lipids, the acidification of intermediate products from hydrolysis, the formation of acetate, and the production of methane. In other words, this review is timely as it discusses for the chemical behavior or the reactivity of different functional groups to better understand the enzymatic catalysis in the transformations of residual proteins, carbohydrates, and lipids to generate biomethane and fertilizers. In the same perspective, this review is to enrich the documentation related to organic reactions catalyzed by enzymes, which occur in the anaerobic degradation of residual organic substances, with emphasis on the structures of organic compounds and reaction mechanisms. This will allow understanding the displacement of the electrons of a reactive entity rich in electrons to another reactive entity that is poor in electrons to form new bonds in products.
Priyanka P. Bidaye, Julio B. Fernandes
Green and Sustainable Chemistry, Volume 9, pp 27-37; doi:10.4236/gsc.2019.92003

A green, rapid and facile method for synthesis of pure rutile TiO2 has been developed. Rutile TiO2 of high purity was synthesized by controlled hydrolysis of TiCl3 in aqueous medium at room temperature. Addition of nitric acid to TiCl3 greatly increased the rate of TiCl3 hydrolysis, crystallization and surface area of the prepared TiO2 powder. The phase obtained in this way was identified by X-ray diffraction. TiO2 synthesized by this method showed a unique flower-like assembly of nanotubes, very high surface area and high photocatalytic activity under visible light irradiation.
Tyler J. Rauwolf, Zhijia Geng, Zachary P. Kinney, Jared L. Renfroe, Jack H. Roireau, Lauren T. Yep, Ram S. Mohan
Green and Sustainable Chemistry, Volume 9, pp 79-84; doi:10.4236/gsc.2019.93005

Luis Álvarez-Santamaría, Eusebio Juaristi, Alexa Berenice Arroyo-Colín, Jorge Palma-Flores, Fanny Araceli Cabrera-Rivera, Jaime Escalante
Green and Sustainable Chemistry, Volume 9, pp 143-154; doi:10.4236/gsc.2019.94011

A simple one-pot procedure for the preparation of imines from the corresponding aldehydes and amines, and their subsequent oxidation reaction with m-CPBA to produce synthetically useful oxaziridines is reported. The method is applicable to imines derived from both aliphatic and aromatic aldehydes and diverse alkyl amines. Short reaction times, essentially quantitative yields, very mild reaction conditions, and easy purification are the main features of the procedure reported herein.
C. Zhao, H. Okada, M. Asakawa, R. Sugimoto, K. Yoshino
Green and Sustainable Chemistry, Volume 9, pp 135-152; doi:10.4236/gsc.2019.94010

Methyl methacrylate (MMA) was grafted onto silk fiber in a one-step emulsion system using a diethylzinc and 1,10-phenanthroline complex. The reaction conditions were investigated by varying temperature and initiator to monomer ratio. Fourier transform infrared (FTIR) spectrum, thermogravimetric analysis (TGA), and scanning electron microscopy (SEC) techniques were used to characterize the structure, thermal stability, and surface morphology of the obtained product, respectively. Grafting of MMA onto silk increased the thermal stability of silk. The FTIR spectrum and SEM images provided further evidence that MMA has been successfully grafted onto the silk fiber. A peak ascribed to the C=O stretching vibration of MMA was detected in the FTIR spectrum of grafted silk fiber, which was not present in the spectrum of pure silk fiber. Moreover, the SEM images illustrated the increase in diameter and surface roughness of grafted silk compared with pure silk. Lastly, the dyeing performance of the modified silk was significantly increased.
Abdalhadi Deghles
Green and Sustainable Chemistry, Volume 9, pp 119-134; doi:10.4236/gsc.2019.94009

Until relatively recently, little has been done of effective technique “zero effluent” to conserve energy and water. Tannery wastewater is known as complex characteristics. In this study batch electrocoagulation experiments were carried out to assess the removal of color and chemical oxygen demand (COD) from tannery wastewater using two types of electrode materials: aluminum and iron. The effects of current density, electrolysis time and initial pH were investigated for tannery wastewater. Therefore, the operating costs for each electrode have been calculated. Based on results, it can be concluded that iron is tremendous to aluminum as electrode material, from COD removal and energy consumption views. All the conclusions of the study revealed that treatment of tannery by EC can be applied as a step of a hybrid treatment.
Heinz Langhals, Maximilian Rauscher, Peter Mayer
Green and Sustainable Chemistry, Volume 9, pp 38-77; doi:10.4236/gsc.2019.92004

A sustainable four-step synthesis of soluble perylenophanes for applications as fluorescent optical functional materials is presented and even allows upscaling because of starting with technical bulk products. Thus, terminal alkenylnitriles were alkylated reduced to amines, condensed with perylenetetracarboxylic bisanhydride and cyclised to cyclophanes by means of double cross metathesis in yields until 69% of isolated dyes. The first metathesis by means of the second-generation Hoveyda-Grubbs-catalyst brings the remaining reactive olefinic groups close together favouring the ring-closure to the cyclophanes where the locked neighboring of chromophores in a skew arrangement induce strong exciton interactions. The latter cause an increased the Stokes’ separation by means of a moderate hypsochromic shift of light absorption and a stronger bathochromic shift of fluorescence. Various applications such as for lasers, photonics, solar collectors or in analytics are discussed.
Akeem Mayowa Azeez, Adeyinka Olubunmi Fasakin, Joshua Iseoluwa Orege
Green and Sustainable Chemistry, Volume 9, pp 1-10; doi:10.4236/gsc.2019.91001

Ethyl ester biodiesel has been produced from a non-edible Jatropha curcas oil. Oil was extracted from the plant seed using n-hexane at 60°C and pretreated by alkaline refining process to reduce the free fatty acid level to less than 1%. Base-catalysed transesterification reaction with absolute ethanol using potassium hydroxide catalyst was adopted for the conversion. Various physicochemical properties of the refined Jatropha curcas oil were investigated. The ethyl ester biodiesel produced was characterised for its fuel properties such as specific gravity at 15°C, flash point, pour point, kinematic viscosity, cetane number, iodine value and higher heating value using American Society for Testing and Materials Standard Methods. The crude and refined Jatropha curcas oil yields were 58.16% and 52.5%. The physicochemical analysis revealed FFA, saponification value and peroxide value of refined Jatropha curcas oil to be 0.58 mg KOH/g, 159.9 and 1.92 m E/kg respectively. The fatty acid composition obtained from gas chromatography (GC) revealed that the oil contained 44.85% oleic acid as the dominant fatty acid, while Margaric 0.01% and Behenic 0.02% the least. The biodiesel yield was 57.6%, and its measured fuel properties conformed with ASTM 6751 and EN 14214 standards.
A. Valadares, S. F. Resende, I. M. F. De Oliveira, R. Augusti
Green and Sustainable Chemistry, Volume 9, pp 94-103; doi:10.4236/gsc.2019.93007

The present work evaluates the feasibility of using the raw material collected from discarded zinc-carbon batteries as heterogeneous catalyst to degrade the dye Indigo Carmine in an aqueous solution. Besides the evident environmental application, this work also presents an economic alternative for the production of new catalysts used to remediate polluted waters. For this, discarded carbon-zinc batteries were gathered, disassembled and their anodic paste collected. After acidic treatment and calcination at 500°C, characterization measurements, i.e. flame atomic absorption spectroscopy (FAAS), nitrogen sorption, X-ray diffraction (XRD) and scanning electron microscopy (SEM), revealed that the so-obtained material consisted mainly of ZnMn2O4. This material acts as a heterogeneous catalyst in a Fenton-like process that degrades the dye Indigo Carmine in water. That is probably due to the presence of Mn(III) (manganese in the +3 oxidation state) in this material that triggers the decomposition of hydrogen peroxide (H2O2) to yield hydroxyl radicals (HO·). Moreover, direct infusion electrospray ionization coupled to high resolution mass spectrometry (ESI-HRMS) was employed to characterize the main by-products resulting from such degradation process. These initial results thus indicate that raw materials from waste batteries can therefore be potentially employed as efficient Fenton-like catalysts to degrade organic pollutants in an aqueous solution.
Shoko Suzuki, Hiroyuki Ito, Shinji Ishizuka, Risehiro Nonaka, Motoyoshi Noike, Takeshi Kodama, Kenji Funaki, Mizuho Taguchi, Taisei Kagaya, Sayaka Sato, et al.
Green and Sustainable Chemistry, Volume 9, pp 105-118; doi:10.4236/gsc.2019.94008

In the field of organic syntheses, the development of environmentally friendly methods based on the concept of green chemistry has been always required. In response to this requirement, we reported solvent- and catalyst-free syntheses of imines using the pressure reduction technique as a key technology. We found that this reaction proceeded very rapidly in the initial stage, but its rate decreased with the passage of time. It was also found that the reaction of benzaldehyde with aniline had a specificity that the phase transition occurred. In this method, the desired imines could be obtained in good to excellent yields, but target compounds had to be given by purifications using organic solvents. Therefore, we tried to develop the perfect synthetic method of imine derivatives without organic or inorganic solvents. We selected two methods and took them into this investigation. One was exactly mixing (1:1, substance ratio) aldehydes and amines and the other was employing lower pressure (>0.1 mmHg, previous method: 1.0 mmHg) at the pressure reducing technique. When this improved synthetic method was performed, it was revealed that pure target imines were obtained in excellent yields without any purification.
Mary-Magdalene Pedavoah, , , Johannes A. M. Awudza
Green and Sustainable Chemistry, Volume 8, pp 208-219; doi:10.4236/gsc.2018.82015

Sindija Zeltkalne,
Green and Sustainable Chemistry, Volume 08, pp 320-333; doi:10.4236/gsc.2018.84022

Ionic liquids (ILs) with 1,3-disubstituted imidazolium cations and the dimethyl phosphate (DMP) anion, as well as the chloride anion were prepared and characterized by 1H NMR spectra, chromatographic and titrimetric purity control, and determination of the moisture content and thermal stability. ILs with the DMP anion decompose only at temperatures above 240°C. These ILs were tested as both reaction media (solvents) and catalysts for the Knoevenagel condensation reaction. The impact of the most significant structure elements of ILs was evaluated for the rates and yields of the condensation reaction. IL anions have the greatest effect on the condensation reactions, and even the chloride anion has some catalytic effect on the Knoevenagel condensation. Side chains in the imidazolium cations influence the reaction course very little. The ability of the imidazolium cations to form hydrogen bonding with the transition state of the condensation reaction leads to a remarkable slowdown in the reaction rates.
Mohammad Ateeq Al-Dosari
Green and Sustainable Chemistry, Volume 8, pp 1-18; doi:10.4236/gsc.2018.81001

This study has compared the ability of paramagnetic element oxides i.e. Pr, Eu, Yb in catalyst oxidation of methane. These have been prepared by precipitation, and then calcined at 600˚C to get M2O3. Methane was then passed through a disk in KBr, and the reactions were conducted at room temperature; 200˚C and then 300˚C. The reaction products were then identified by F.T.I.R spectroscopy. It was observed that these oxides have extracted the protons from methane and the CH3• radicals were evidently formed. This focused radical react further to give CH3O, C2H6 and the formation of Propionic acid is reported as one of the catalytic reaction products. The study also indicated the presence of aromatic products and in some instances, phenol was identified. Thereafter, the mechanism of the reaction was envisaged. For all the catalysts the conversion increases relatively with increasing the reaction temperature. The study can deduce that these oxides have the same ability as those of high paramagnetic properties to extract the proton, but the products are trapped and react further on the surface of the oxide.
, Dominik Zgela, Arthur Haffner, Charlotte Koschnick, Kerstin Gottschling, Christian Paulik
Green and Sustainable Chemistry, Volume 8, pp 247-274; doi:10.4236/gsc.2018.83017

A significant impact of this work on the use of polymers is expected because the developed organo-nano particles (ONP) mixed into standard polymers will make them unique and traceable. The doping of polymers with non migrating ONP was demonstrated and applications for the recycling of plastics were discussed. Thus, perylene derivatives were linked to polymerisable vinyl groups and copolymerized under RAFT conditions (Reversible Addition Fragmentation chain Transfer) with styrene and methylmethacrylate, respectively, to obtain fluorescent ONP with sizes of 40 nm or even less and narrow distributions of molecular weight in most cases with polydispersities PD of 1.1 and lower.
Nurudeen Ishola Mohammed, Nassereldeen Ahmed Kabbashi, , Sarina Sulaiman
Green and Sustainable Chemistry, Volume 8, pp 74-91; doi:10.4236/gsc.2018.81006

Solid oxide catalysts derived from various renewable sources have produced significant yield of methyl esters of enhanced purity. These materials are sourced for due to their advantages ranging from low cost, recoverability and reusability, environmental benign-ness, thermal stability and high quality product generation. For a possible greener production process, many researchers in literature reported the use of biomass-derived heterogeneous catalyst in biodiesel synthesis producing high quality pure product. The catalysts were majorly modified through simple physical cost effective and energy saving operations. This paper explores some of these bio-based heterogeneous catalyst used in biodiesel production via transesterification and esterification approach and their performance in FAME yield and conversion. The feedstock consideration which warrant the route selection, various approaches that are adopted in biodiesel production, performance of renewable heterogeneous catalyst and the measures that were adopted to enhance efficiency of the catalyst were considerably highlighted. It is observed that the prospects of organic-based solid catalyst in biodiesel development is a promising enterprise compared to the conventional methods utilizing homogeneous chemical catalyst, which generates wastewater requiring treatment before disposal and generates product that may cause engine malfunction. This review work aimed at providing detailed and up-to-date record of the trend in renewable catalyst development in biodiesel synthesis. This is expected to inform a suitable selection and reaction conditions in the development of biodiesel from the very many feed stocks.
Ishwinder Kaur, Girish Sahni
Green and Sustainable Chemistry, Volume 8, pp 92-114; doi:10.4236/gsc.2018.81007

The complexity of plant cell walls impedes the conversion of cellulosic biomass to sugars. Pretreatment becomes a necessity to increase the digestibility of biomass. An in-depth understanding of the structure and underlying mechanisms governing deconstruction process is important. In the present study, the comprehensive investigation of morphological and structural changes in corn stover and sugarcane bagasse following ionic liquids dissolution and alkaline extraction was done using Fourier transform infrared spectroscopy, Thermogravimetric analysis, Confocal scanning laser microscopy, Atomic force microscopy and Dynamic light scattering studies. Both the substrates were pretreated with ILs 1-ethyl-3-methylimidazolium acetate and 1-butyl-3-methylimidazolium acetate followed by alkaline extraction. The pronounced changes such as lignin, hemicelluloses removal and decreased cellulose crystallinity after the pretreatments lead to the structural transformation of matrix polymers. The enzymatic hydrolysis showed 90% theoretical sugar yield in case of sugarcane bagasse and 80% in corn stover following synergistically combined pretreatments.
, Angela M. Díaz, , Rafael Pérez, , David S. Zepeda
Green and Sustainable Chemistry, Volume 8, pp 180-189; doi:10.4236/gsc.2018.82013

Kouadio Marc Cyril, Kouakou Adjoumani Rodrigue, Kra Essi, Trokourey Albert, Akichi Agboue
Green and Sustainable Chemistry, Volume 8, pp 288-293; doi:10.4236/gsc.2018.83019

The determination of biochemical methane potential (BMP) is very important for the valorization of food wastes. This study is focused on the evaluation of the theoretical methane production from chemical oxygen demand (COD) of some food wastes, coming out Akouedo landfill. Almost all of the considered samples exhibited methane theoretical yields equal to about 402.5 - 507.8 mLCH4/gVS. These results indicate the suitability of all the studied food wastes from Akouedo landfill to be converted into energy.
Konan Edmond Kouassi, Abollé Abolle Abolle, Kouassi Benjamin Yao, David Boa, Kopoin Adouby, , Rajeshwar Dayal Tyagi
Green and Sustainable Chemistry, Volume 8, pp 39-61; doi:10.4236/gsc.2018.81004

J. Mwangi Kahindo, Sumesh C. Chhabra, Odalo J. Ochieng, Thomas Thoruwa
Green and Sustainable Chemistry, Volume 8, pp 62-73; doi:10.4236/gsc.2018.81005

Yutaka Okada, Masahiro Yamabe
Green and Sustainable Chemistry, Volume 8, pp 130-138; doi:10.4236/gsc.2018.81009

The reaction between diphenylmethanols and substituted benzenes is useful to yield triarylmethane derivatives which are important skeletons in various functional materials and biologically relevant substances. The Reactions were carried out under microwave irradiation as environmentally-friendly method. In cyclohexane, the reaction was accelerated under microwave irradiation as compared to under conventional heating. Also, when more than 0.8 equivalents of iron(III) chloride were used, the acceleration was observed. Notably, when iron(III) chloride and arenes were combined, the temperature of the reaction solution rose to 40°C. It is considered that a chemical species was formed upon coordination of iron(III) chloride to the diphenylmethanols or arenes.
, Oswald Krotz
Green and Sustainable Chemistry, Volume 8, pp 311-319; doi:10.4236/gsc.2018.84021

Sureshbabu Jayachandra, Madhuresh Kumar Sethi, Vipin Kumar Kaushik, Vijayakrishna Ravi, Saiprasad Kottolla, Vikas Chandra Dev, Purbita Chakraborty
Green and Sustainable Chemistry, Volume 8, pp 190-207; doi:10.4236/gsc.2018.82014

Abollé Abollé, Konan Edmond Kouassi, , Albert Trokourey, Kouassi Benjamin Yao, Ado Ado Gossan
Green and Sustainable Chemistry, Volume 8, pp 19-31; doi:10.4236/gsc.2018.81002

Green and Sustainable Chemistry, Volume 8, pp 221-246; doi:10.4236/gsc.2018.83016

Before proposing an innovative process for the coproduction of ethyl and butyl acetates, the individual syntheses of ethyl acetate and butyl acetate by two different routes were first studied. These syntheses involved the reaction of ethanol or n-butanol with acetic acid or acetic anhydride in the presence of ion exchange resins: Amberlyst 15, Amberlyst 16, Amberlyst 36 and Dowex 50WX8. Kinetic and thermodynamic studies were performed with all resins. The lowest activation energy (Ea) value was obtained with Dowex 50WX8, which was identified as the best-performing resin, able to be reused at least in four runs without regeneration. The presence of water-azeotropes during the synthesis of ethyl acetate makes its purification difficult. A new strategy was adopted here, involving the use of ethanol and acetic anhydride as the starting material. In order to minimize acetic acid as co-product of this reaction, a novel two-step process for the coproduction of ethyl and butyl acetates was developed. The first step involves the production of ethyl acetate and its purification. Butyl acetate was produced in the second step: n-butanol was added to the mixture of acetic acid and the resin remaining after the first-step distillation. This process yields ethyl acetate and butyl acetate at high purity and shows an environmental benefit over the independent syntheses by green metrics calculation and life cycle assessment.
Michael Bong Alang, Maurice Kor Ndikontar, Yahaya Muhammad Sani, Peter T. Ndifon
Green and Sustainable Chemistry, Volume 8, pp 275-287; doi:10.4236/gsc.2018.83018

Biolubricant was synthesized from Cameroon palm kernel oil (PKO) by double transesterification, producing methyl esters in the first stage which were then transesterified with trimethylolpropane (TMP) to give the PKO biolubricant in the presence of a base catalyst obtained from plantain peelings (municipal waste). The yields from both catalysts were significantly similar (48% for the locally produced and 51% for the conventional) showing that the locally produced catalyst could be valorized. The synthesized biolubricant was characterized by measuring its physical and chemical properties. The specific gravity of 1.2, ASTM color of 1.5, cloud point of 0°C, pour point of -9°C, viscosities at 40°C of 509.80 cSt and at 100°C of 30.80 cSt, viscosity index of 120, flash point greater than 210°C and a fire point greater than 220°C were obtained. This synthesized biolubricant was found to be comparable to commercial T-46 petroleum lubricant sample produced industrially from mineral sources. We have therefore used local materials to produce a biolubricant using a cheap base catalyst produced from municipal waste.
Green and Sustainable Chemistry, Volume 8, pp 295-310; doi:10.4236/gsc.2018.84020

Manganese (Mn) is an essential element for human body. However, elevated concentration of manganese causes severe problem and disease. Acid mine drainage (AMD), wastewater generated due to open-pit mining, commonly contains Mn with exceeded concentration. This study is to investigate the improvement of ball-milling modified Indonesian natural bentonite (INB) for manganese (Mn) removal from AMD and to increase the pH through batch and column sorption test as a passive treatment system approach. The batch sorption test result showed the maximum Mn adsorbed (Qm) on INB from the Langmuir model increased from 4.69 to 17.12 mg/g after milling. The column sorption test result also showed the amount of Mn adsorbed on INB until breakthrough time (qu) and until saturation time (q) increased after milling. The qu increased from 1.27 to 10.06 mg/g, and the q increased from 4.55 to 12.91 mg/g. The mass transfer zone (MTZ) became significantly shorter after milling from 0.22 to 0.07 cm. The Thomas model exhibited the equilibrium uptake of Mn (q0) increased after milling from 3.91 to 13.72 mg/g. In equilibrium condition, both unmilled and milled INB showed the pH increased from ≈3 to 8.
Chengping Zhang, Ni Zhang, Xiaoqing Jia, Nan Li, Hengdao Quan
Green and Sustainable Chemistry, Volume 8, pp 115-129; doi:10.4236/gsc.2018.81008

The isomerization of hydrofluorocyclopentenes promoted by fluoride anion was investigated. It was found that two processes were responsible for interconversion of the isomers: an allylic syn-addition/elimination of fluoride anion that does not change the mutual positions of hydrogen atoms but is responsible for transfers of fluorine atoms, and a fluoride anion-assisted deprotonation/protonation which does not change the mutual positions of fluorine atoms but is responsible for transfers of hydrogen atoms. In the deprotonation, HF can easily capture excess fluoride anion to form HF2- anion which can probably inhibit the protonation.
, Isabelle Ziegler-Devin, , Martina Bremer, Anton Hoffmann, Steffen Fischer, Marie-Pierre Laborie, Nicolas Brosse
Green and Sustainable Chemistry, Volume 7, pp 114-140; doi:10.4236/gsc.2017.72010

This study aims at investigating the impact of ionic liquid extraction on lignin structure by studying the mechanism of lignin depolymerization in 1-ethyl-3-methylimidazolium acetate EMIM[OAc]) and comparing it with that of organosolv and milled wood methods. Ionic liquid mediated lignin (ILL) using EMIM[OAc]), ethanol organosolv lignin (EOL) and milled wood lignin (MWL) were isolated from Typha capensis (TC) and subjected to several analytical characterizations. Experimental data shows that ILL exhibited a relatively lower degree of condensation, lower aromatic C-C structures and a higher aliphatic OH with values of 0.42/Ar, 1.94/Ar and 1.33/Ar moieties compared with EOL values of 0.92/Ar, 2.22/Ar and 0.51/Ar moieties respectively. The ILL was depolymerized under mild conditions giving relatively higher β-aryl ether linkages content, higher molecular mass, and exhibited closer structures and reactivity to native lignin than EOL. These insights on TC lignin depolymerization in EMIM[OAc]) acetate may contribute to better value-addition of lignocellulosic biomass.
Alexander Buzynin, Yury Buzynin, Vladimir Shengurov, Vladimir Voronkov, Ansgar Menke, Albert Luk’Yanov, Vitaly Panov, Nickolay Baidus
Green and Sustainable Chemistry, Volume 7, pp 217-233; doi:10.4236/gsc.2017.73017

In the present paper, some novel opportunities for the development of high-efficient Si and III-V-based solar cells are considered: energy-saving environment friendly low-temperature technology of forming p-n junctions in Si (1), elaboration of structurally perfect GaAs/Ge/Si epitaxial substrates (2) and application of protective antireflecting coatings based on cubic zirconia (3). As a result: 1) New technique of forming p-n junctions in silicon has been elaborated. The technique provided easy and comparatively cheap process of production of semiconductor devices such as solar cells. The essence of the technique under the study is comprised in formation p-n junctions in silicon by a change of conductivity in the bulk of the sample occurring as a result of redistribution of the impurities, which already exists in the sample before its processing by ions. It differs from the techniques of diffusion and ion doping where change of conductivity and formation of p-n junction in the sample occur as a result of introduction of atoms of the other dopants from the outside; 2) The conditions for synthesis of GaAs/Ge/Si epitaxial substrates with a thin (200 nm) Ge buffer layer featured with (1 - 2) × 105 cm-2 density of the threading dislocation in the GaAs layer. Ge buffer was obtained by chemical vapor deposition with a hot wire and GaAs layer of 1 μm thick was grown by the metal organic chemical vapor deposition. Root mean square surface roughness of GaAs layers of the less than 1 nm and good photoluminescence properties along with their high uniformity were obtained; 3) The conditions ensuring the synthesis of uniform functional (buffer, insulating and protective) fianite layers on Si and GaAs substrates by means of magnetron and electron-beam sputtering have been determined. Fianite films have been shown to be suitable for the use as an ideal anti-reflecting material with high protective and anticorrosive properties.
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