Showing papers in "Green and Sustainable Chemistry in 2013"

Recent Applications of Electrocoagulation in Treatment of Water and Wastewater—A Review

Abstract: During the last two decades, and particularly during the last few years, the environmental sector has shown a largely growing interest in the treatment of different types of water and wastewater by electrocoagulation (EC). The aim of this work was to review studies, conducted mainly during 2008-2011, on the wide and versatile range of feasible EC applications employed in the purification of different types of water and wastewater. The EC applications discussed here were divided into 7 following categories: tannery, textile and colored wastewater; pulp and paper industry wastewater; oily wastewater; food industry wastewater; other types of industrial wastewater; surface water as well as model water and wastewater containing heavy metals, nutrients, cyanide and other elements and ions. In addition, this paper presents an overview of the optimum process conditions (treatment times, current densities, and initial pH) and removal efficiencies (mostly high) achieved for the EC applications discussed. In the vast majority of the studies discussed in this review, the aforementioned values were found to be in the range of 5 - 60 min (typically less than 30 min), 10 - 150 A/m 2 and near neutral pH, respectively. Both operating costs and electrical energy consumption values were found to vary greatly depending on the type of solution being treated, being between 0.0047 - 6.74 €/m 3 and 0.002 - 58.0 kWh/m 3 , but in general they were rather low (typically around 0.1 - 1.0 €/m 3 and 0.4 - 4.0 kWh/m 3

Ionic Liquid as Useful Media for Dissolution, Derivatization, and Nanomaterial Processing of Chitin

Abstract: This paper reviews studies on dissolution, derivatization, and nanomaterial processing of chitin using an ionic liquid as useful media. Because chitin is the second most abundant polysaccharide on the earth after cellulose, there is major interest in conversion of native chitin resources into various useful materials after proper dissolution in suitable solvents. For the derivatization and nanomaterial processing of chitin, the author has been focusing on ionic liquids because which have been found to be used as good solvents for cellulose in a past decade. The author found that an ionic liquid, 1-allyl-3-methylimidazolium bromide (AMIMBr), dissolved chitin in concentrations up to 4.8 wt% and mixtures of the higher amounts of chitin with AMIMBr gave ion gels. Acetylation, the simplest derivatization, of chitin using acetic anhydride was achieved in the AMIMBr solvent under mild conditions. Furthermore, the chitin nanofibers were fabricated by regeneration technique from the chitin ion gel with AMIMBr using methanol. Moreover, filtration of the chitin nanofiber dispersion with methanol was carried out to give a chitin nanofiber film. The chitin nanofiber-poly(vinyl alcohol) composite film was also prepared from the ion gel by co-regeneration method.

Silica-Grafted Ionic Liquids as Recyclable Catalysts for the Synthesis of 3,4-Dihydropyrano[c]chromenes and Pyra-no[2,3-c]pyrazoles

Abstract: Silica-grafted N-propyl-imidazolium hydrogen sulfate ([Sipim]HSO4) is employed as a recyclable heterogeneous ionic liquid catalyst for the synthesis of 3,4-dihydropyrano[c]-chromenes by the reaction of aromatic aldehydes, malononitrile and 4-hydroxycoumarin at 100°C under solvent-free conditions. Also, heterogeneous ionic liquid catalyst was used for the synthesis of pyrano[2,3-c]-pyrazoles by the reaction of aromatic aldehydes, malononitrile and 3-methyl-l-phenyl-5-pyrazolone at 110°C under solvent-free conditions. The heterogeneous ionic liquid showed much the same efficiency when used in consecutive reaction runs.

The Best Available Technology of Water/Wastewater Treatment and Seawater Desalination: Simulation of the Open Sky Seawater Distillation

Abstract: This review suggests the concept of the best available technology of water/wastewater treatment and seawater desalination which is in fact a simulation of the seawater distillation at the open sky: coagulation in salty water aerated basin/ coagulation using seawater as coagulant solution with distillation using stored solar energy followed by waterfall on a natural mountain. This natural, green, and technico-economical technology is composed of three steps: the first one is coagulation which may be achieved: 1) in salty water aerated basin (air stripping, AS; dissolved air flotation, DAF) where the raw water is “diluted” in seawater; or 2) in “conventional” coagulation using seawater as coagulant solution instead of alum/ferric salts. The first option seems to be more natural as it simulates river water dilution in seawater and the second one is more practical for “rapid” water consummation. For colloids and microorganisms’ removal, double-layer compression and charge neutralisation, as main coagulation and disinfection mechanisms, would be involved in the first and second options, respectively. Aerated basin (AS/DAF) reproduces the natural aeration to simulate healthy natural water basin. Using stored solar energy, distillation as the best liquid-solid/liquid-liquid separation process provides the removal of dissolved pollutants. For well balanced calco-carbonic equilibrium, the last step of this green treatment is the waterfall on a natural mountain providing useful gases, dissolved oxygen and carbon dioxide, and mineral salts to the water.

n-Dodecylbenzene Sulfonic Acid (DBSA) as a Novel Brønsted Acid Catalyst for the Synthesis of Bis(indolyl)methanes and Bis(4-hydroxycoumarin-3-yl)methanes in Water

Abstract: n-Dodecylbenzene sulfonic acid (DBSA) as a novel, biodegradable, and efficient Br?nsted acid catalyst used for the reaction of indoles/4-hydroxy coumarin with aldehydes to obtain a bis(indolyl)methanes/bis(4-hydroxycoumarin-3-yl)methanes, respectively. The catalyst exhibited remarkable activity, and tolerated a wide variety of functional groups providing the desired bis(indolyl)methanes and bis(4-hydroxycoumarin-3-yl)methanes in good to excellent yield (70%-96%) in water.

Characterization of Some Jordanian Crude and Exhausted Olive Pomace Samples

Abstract: In an attempt to provide a set of specifications for the use and trade of the olive pomace in Jordan, several samples of the crude and laboratory-prepared exhausted (oil-free) olive pomace have been subjected to a thorough thermochemical characterization. Such characterization included determination of fat content by using n-hexane and Soxhlet extractor, ultimate and proximate analyses obtained by using an elemental analyzer and a thermogravimetric procedure, respectively, gross and net calorific values obtained by using adiabatic oxygen bomb calorimetry, mineral content (ash), and analysis of the pyrolysis thermograms in terms of specified temperatures and residual masses associated with such temperatures as obtained under an inert atmosphere of nitrogen gas at a flow rate of 100 ml per min and a heating rate of 20°C per min from room temperature up to 600°C. The properties of both the crude and the exhausted olive pomace were compared. The gross calorific values and the results of the ultimate analyses for the two pomace types were found to correlate very well as indicated by the use of a literature correlation formula usually used for estimating the gross calorific value of a fuel when its ultimate analysis is known. Other literature correlation formulas used for estimating the gross calorific value from the proximate analysis data were also used to check the adequacy of our procedure for getting the proximate analysis from the thermogravimetric pyrolysis thermograms.

Glycerol-Based Carbon-SO 3 H Catalyzed Benign Synthetic Protocol for the Acetylation of Alcohols, Phenols and Amines under Solvent-Free Conditions

Abstract: A simple and efficient solvent-free method was developed for the acetylation of alcohols, phenols and amines in excellent yields employing glycerol-based sulfonic acid (-SO3H) functionalized carbon catalyst under environmentally benign reaction conditions. The salient features of this protocol are the short reaction time, ease of product isolation and reusability of the carbon catalyst.

Synthesis and Characterization of Novel Brønsted-Lewis Acidic Ionic Liquids

Abstract: To meet the demands of some kinds of reactions catalyzed simultaneously by Br?nsted acid and Lewis acid catalyst, two novel Br?nsted-Lewis acidic ionic liquids, 1-carboxyethylene-3-(4-zinc acetate sulfobutyl) imidazolium chloride ([CH3COO-Zn-O3S-bim-CH2CH2COOH]Cl) and 1-(1,2-dicarboxy) ethylene-3-(4-zinc acetate sulfobutyl) imidazolium chloride ([CH3COO-Zn-O3S-bim-C4H5O4]Cl) were synthesized, in which both Br?nsted and Lewis acidic sites existed in the cation. The structures of the ionic liquids were determined by means of FT-IR, 1H NMR and elemental analysis. The results of Py-IR analysis indicated that the two novel ionic liquids have both Br?nsted and Lewis acid properties. The acid strength values (H0) of the ionic liquids were measured utilizing the UV-visible spectroscopy combined with Hammett indicator method, and the acid amount of them was determined by acid-base titration.

Solvent Free One-Pot Synthesis of 1,2,4,5-Tetrasubstituted Imidazoles Catalyzed by Secondary Amine Based Ionic Liquid and Defective Keggin Heteropoly Acid

Abstract: Secondary amine based ionic liquid and defective Keggin type heteropoly acid (HPA) are separately used for efficient one-pot four-component synthesis of 1,2,4,5-tetrasubstituted imidazoles assisted by microwave (MW). Eco-friendly solvent free procedure, short reaction time, high yield of products and reusability of catalysts are important features of the synthesis. A comparative study on the efficiency of the two catalysts is reported. This work further demonstrates the alternate use of urea, instead of often used ammonium acetate, as source of nitrogen.

A Green Protocol for Efficient Synthesis of 1,8-Dioxo-Octahydroxanthenes Using Ionic Liquid

Abstract: A clean, simple, efficient synthesis of 1,8-dioxo-octahydroxanthenes derivatives using ionic liquid 1-butyl, 3-me- thylimidazolium perchlorate ([bmim] ClO4) has been developed. The method provides several advantages such as simple work up, environmental friendliness and excellent yields in short reaction time. The ionic liquid [bmim] ClO4 used was recovered and reused for three times.

Carbonylative Coupling of 4,4’-Diiodobiphenyl Catalyzed by Pd(NHC) Complex

Abstract: To develop a luminescent material with high color purity, luminous efficiency, and stability, we synthesized diketone by carbonylative Suzuki coupling in the presence of Pd(NHC) complex as the catalyst. Carbonylative coupling of 4,4’-diiodobiphenyl and phenylboronic acid was investigated to study in detail the catalytic ability of the Pd(NHC) complex. Reactions were carried out using both CO and metal carbonyls. Bis-(1,3-dihydro-1,3-dimethyl-2H-imidazol- 2-ylidene) diiodo palladium was used as the catalytic complex. Reaction products biphenyl-4,4’-diylbis (phenyl- methanone) 3 and (4’-iodobiphenyl-4-yl)(phenyl) methanone 4 were obtained as a result of CO insertion into the palladium(II)-aryl bond. However, when pyridine-4-yl boronic acid was used in place of phenylboronic acid as the starting reagent, synthetic reaction yielding 3 and 4 were found not to occur.

Direct Preparation of Hydrogen and Carbon Nanotubes by Microwave Plasma Decomposition of Methane over Fe/Si Activated by Biased Hydrogen Plasma

Abstract: Methane was decomposed to hydrogen and carbon nanotubes (CNTs) by microwave plasma, using Fe/Si catalyst activated by biased (—150 V) hydrogen plasma for various treatment times. Upon exposure to biased hydrogen plasma, the catalyst surface becomes lumpy within 1 min, coheres between 5 and 10 min and forms particles after 20 min. The methane conversion increased up to 93% over the treatment time of 5 min. The hydrogen yield showed as similar tendency as the methane conversion and kept 83% at treatment time of 5 min. The treatment time up to 1 min increased the amount of deposited carbon, and after treatment time of 5 min it dropped; then again after treatment time of 20 min, it increased to reach a maximum value of 22 gc/gcat. Deposited carbon was found to be consisted of carbon nanotubes. It grew vertically on the catalyst surface and reached a maximum length of 30.7 nm after treatment time of 10 min. Multiple types of CNTs were present, and the CNT diameters decreased with increasing plasma treatment time.

Green Chemistry Approach to Fast and Highly Efficient One-Pot Synthesis of Bis-Isoxazolyl-1,2,5,6-Tetrahydro Pyridine-3-Carboxylates

Abstract: The synthesis of the bis-isoxazolyl-1,2,5,6-tetrahydro pyridine-3-carboxylates is achieved in high yield without the production of toxic waste products by using room temperature ionic liquid (RTILs) triethyl ammonium acetate (TEAA). The RTIL TEAA played the dual role of efficient green solvent as well as recyclable catalyst.

Interactions in Aqueous Solution of a Zwitterionic Surfactant with a Water Treatment Protein from Moringa oleifera Seeds Studied by Surface Tension and Ultrasonic Velocity Measurements

Abstract: The interaction of a zwitterionic surfactant with the water treatment protein extracted from Moringa oleifera has been investigated by surface tension and ultrasonic velocity measurements. The critical micelle concentration (CMC) of zwitterionic surfactant was determined to be 2.4 ± 0.3 mM by both techniques and the partial specific volume ν = 0.78 ± 0.06 cm3/g for the protein was found. There seems to be a mild interaction between the protein and the surfactant as shown by surface tension measurements. The ultrasonic velocity was found to decrease in the vicinity of the critical micelle concentration which may be due to micelle aggregates formation and the protein caused a shift of the surfactant’s CMC to a higher concentration.

Garlic Clove Catalyzed Biginelli Reaction in Water at Ambient Temperature

Abstract: A simple, green and highly efficient procedure for the Biginelli condensation reaction of aldehydes, β-ketoesters, urea or thiourea catalyzed by crushed garlic clove at ambient temperature is reported.

Oligoalkylnaphthenic (C6-C12) Oils Obtained in the Presence of Ti-Containing Ionic-Liquid Catalysts

Abstract: In this present paper, the result of C6-C12 α-olefins oligomerizaton in the presence of recyclable chloroaluminate type ionic-liquid catalysts and their combination with Ti-containing complexes is presented. By different methods of analysis the composition and structure of oligoalkylnaphtenic products obtained in the presence of ionic-liquid catalysts and Ti-containing modifiers have been studied.

An Efficient FeCl 3 Catalyzed Synthesis of N,N'-Diarylformamidines

Abstract: An efficient FeCl3 catalyzed synthesis of N,N’-diarylformamidines using triethylorthoformate (1 equivalent) and primary aryl amines (2 equivalents) at ambient temperature has been described. This methodology provides an eco-friendly and simple procedure without using any hazardous and expensive chemicals.

New Method for the Synthesis of 1-Methylimidazolium Trifluoroacetate and Its Application in Biginelli Reaction

Abstract: A new method for the synthesis of 1-methylimidazolium trifluoroacetate ([Hmi]Tfa), a protic ionic liquid (PIL), under ultrasonic irradiation has been developed. In addition, the product [Hmi]Tfa was successfully employed as solvent and catalyst in Biginelli reaction to prepare 3,4-dihydropyrimidinones (DHPMs) in high yield under mild reaction conditions.

Use of Solid-Supported Reagents towards Synthesis of 2-Arylbenzoxazole, 3, 5-Diarylisoxazole and 1, 3, 5-Triarylpyrazole

Abstract: Herein we report a convenient and efficient synthesis of 2-Arylbenzoxazole from the Schiff’s bases of 2-Aminophenol, 3, 5-Diarylisoxazole from α, β-unsaturated ketoxime and 1,3,5-Triarylpyrazole from 2-pyrazoline and N-Arylhydrazone by using milder, less toxic and less expensive-NBS-SiO2, KMnO4-Al2O3, PCC-SiO2 and ACC-Al2O3 as solid-supported oxidizing agents at room temperature. Within the framework of Green Chemistry, the use of solid supported reagents has many advantages such as 1) they are easy to remove from reactions by filtration 2) excess reagents can be used to drive the reaction without introducing any difficulties in purification 3) such solid-supported reagents react differently, mostly more selectively, than their unbound counterparts and 4) toxic, noxious and explosive chemicals are handled more safely when contained on solid support.

AlCl3 Supported Catalysts for the Isomerization of Endo-Tetrahydrodicyclopentadiene

Abstract: Two of zeolites such as Hβ and HY, and mesoporous HMCM-41 were used as supports to immobilize AlCl3 for the investigation of the isomerization of endo-tetrahydrodicyclopentadiene (endo-TCD). The dependences of porous structure and surface acidity of the AlCl3 immobilized catalysts on the activity and selectivity were studied. Based on characterization studies, both the large pore diameter and strong acid sites of the supported catalysts contributed to the high activities in the endo-TCD conversion. And specifically the stronger Lewis acid sites seems to be responsible for the higher selectivity onto exo-TCD, and the stronger Br?nsted acid sites were crucial to the formation of adamantane through the further isomerization of exo-TCD.

An Improved Protocol for Biginelli Reaction

Abstract: [Hmim][Tfa] was used as catalyst for the Biginelli reaction under microwave heating. Low catalyst loading, reduced reaction time and operational simplicity are the main highlights of this protocol. The proposed protocol was found active in the synthesis of 30 different biologically active compounds.

Synthesis of Substituted N-Alkylamines in Aqueous Media

Abstract: Synthesis of N-substituted aminopentanes based on the reaction of the amines with 1-brompentanes (n-and iso-structure) and amino (bis-amino) hydroxy compounds via opening reaction of epoxides with amines environmentally friendly practices in water medium has been developed. Structure of obtained compounds by elemental analysis and IR-, 1H and 13C NMR-spectroscopy were confirmed.

Ag, Hg and Cr Precipitation for Recycling Derived of Hazardous Liquid Waste

Abstract: Production of different compounds can generate large amounts of hazardous wastes which are dangerous to the environment and human health. The disposal or treatment of hazardous liquid waste rich in heavy metals like silver (Ag), mercury (Hg) and chromium (Cr) is difficult due to the strong acidity and toxicity which usually present in these contaminants. For this study, several research works were reviewed in order to obtain an efficient and viable treatment in time and removal efficiency. A series of chemical precipitations were evaluated for efficiency in the reduction of heavy metals in liquid waste. The precipitation of all three metals lasted 30 minutes and after treatment the wastewater presented concentrations of 0.064 mg·L-1 Ag, 0.010 mg·L-1 Hg and 0.048 mg·L-1 Cr, with a standard pH (7.5-8.5); with removal efficiencies of 94.31% for Ag, 99.99% for Hg and 98.17% for Cr.

Green Cycle: Sulfate Sorption from Natural Water on Anionic Clay Compound Obtained from Industry Wastewater

Abstract: In this paper we are describing a green cycle process. The first step was a novel hydrotalcite-like compound (HTLC) synthesized by a co-precipitating method, under standard ambient temperature and pressure, using chemical industry wastewater rich in divalent and trivalent cations, activated by a thermal treatment and finally characterized by scanning electron microscopy (SEM), energy dispersive X-ray fluorescence (EDS) and thermogravimetric analysis (TGA). The second step was a series of batch sorption tests performed with this activated HTLC and untreated underground sulfurous water from the state of Puebla, Mexico. The HTLC calcined at 500°C/3 h exhibited the best sorption ability for ions, demonstrated a decrease of the hardness and sulfate ions to below the regional legal standards for drinking water. Once inactive after being used in water treatment, the sorbed ions were removed by ion exchange in a carbonate-containing solution, resulting in an 80% recycling of the material which upon activation demonstrated a retained capacity for water treatment. This recyclability suggests the exciting possibility of this novel compound as an efficient “green” technology in water treatment processes.

Ionic Liquid-Based Ultrasound-Assisted Emulsification Microextraction Coupled with HPLC for Simultaneous Determination of Glucocorticoids and Sex Hormones in Cosmetics

Abstract: An effective and environmentally friendly method based on ionic liquid-based ultrasound-assisted emulsification microextraction(IL-USAEME) and high performance liquid chromatography (HPLC) has been developed for the determination of nine hormones including three glucocorticoids, one androgen and five progestogens in cosmetics. Several factors that affect the extraction efficiency, such as the kinds and volume of ionic liquid, salt concentration, ultrasonic power and time, and centrifugation time were investigated and optimized. Under the optimum extraction condition, the recoveries of analytes ranged from 85.97% to 108.84% except prednisolone (62.30%). The intraday and interday precision was below 2.51% and 3.30%, respectively.

Simultaneous Waste Water Purification via Photocatalysis and Seed Germination

Abstract: Preliminary results of our study related to simultaneous waste water purification by photocatalytic degradation of organic impurity (Methylene Blue dye) and its effects on seed germination are presented here. It is interesting and important to know that complete degradation of the dye occurs within 2 hours and does not adversely affect the seed germination process. It is concluded that waste water purification by photocatalysis and seed germination (agriculture) can be carried out simultaneously, opening a way for advanced agriculture.

Di(isothiocyanato)bis(4-methyl-4’-vinyl-2,2’-bipyridine) Ruthenium(II) Films Deposited on Titanium Oxide-Coated, Fluorine-Doped Tin Oxide for an Efficient Solar Cell

Abstract: Dye-sensitized titanium oxide electrodes were prepared by immobilizing a novel ruthenium complex, di(isothiocy- anato)bis(4-methyl-4’-vinyl-2,2’-bipyridine)ruthenium(II) [(NCS)2(mvbpy)2Ru(II)] or the ruthenium complex/sodium 4-vinylbenzenesulfonate onto the surface of a titanium oxide-coated, fluorine-doped tin oxide (TiO2/FTO) electrode through a new electrochemically initiated film formation method, in which the electrolysis step and the film deposition step were individually performed. The incident photon-to-current conversion efficiency (IPCE) of the Ru complex film on a TiO2/FTO electrode was disappointedly insufficient (1.2% at 440 nm). In sharp contrast, the Ru(II) complex/so- dium 4-vinylbenzenesulfonate composite film deposited on the surface of a TiO2/FTO electrode showed maximum IPCE of 31.7% at 438 nm.

Aqueous-Phase, Palladium-Catalyzed Suzuki Reactions under Mild Conditions

Abstract: Water-soluble ionic liquid-supported diols have been used as phosphine-free ligands in Suzuki couplings of aryl idides/bromides/chlorides under mild conditions in aqueous solvent. It was found that 2,2-bis((1-hexylimidazolium)-mehyl) propane-1,3-diol hexafluorophosphate (4) in combination with palladium (II) salts gave the most significant catalyst. Suzuki couplings of aryl iodides/bromides occurred efficiently at room temperature in water/acetonitrile. Notably, the reactions of hydrophilic aryl bromides gave high yields in neat water. The catalyst PdCl2-4 was recycled five times in Suzuki couplings in water before catalyst activity began to significantly drop. The average yield of five cycles was >95% per cycle.

Behaviour of Roofing Materials Facing to Micro-Organisms

Abstract: An accelerated water-streaming test was used to evaluate several roofing materials regarding their behavior to colonization by algae, by closely reproducing the phenomenon of natural biological soiling. A set of roofing materials with defined physical and chemical characteristics was thus investigated against the colonization by algae. Porosity, roughness and chemical composition showed to be factors of influence in the establishment of those micro-organisms.