Green Chemistry (v.14, #4)
Front cover (857-857).
Inside front cover (858-858).
Contents list (859-874).
Modeling and predicting aquatic aerobic biodegradation – a review from a user's perspective by Christoph Rücker; Klaus Kümmerer (875-887).
In the context of sustainable and green chemistry, the ‘benign by design’ concept requires information on a compound's biodegradability to be available at an early stage, even before synthesis. Computer models for predicting biodegradation therefore are increasingly important. In this work various approaches to predict aquatic aerobic biodegradation are critically reviewed from a user's point of view. Some fundamental problems in modeling biodegradation are discussed, as well as more general issues in modeling of compound properties by quantitative structure–property/activity relationships (QSPR/QSAR).
Photooxygenations in a bubble column reactor by Alexander Yavorskyy; Oksana Shvydkiv; Carolin Limburg; Kieran Nolan; Yan M. C. Delauré; Michael Oelgemöller (888-892).
A novel column reactor was constructed and successfully applied to dye-sensitized photooxygenation reactions in aqueous alcohol solutions. The air flow pattern within the narrow glass column could be controlled via the size of the air inlet capillary. Using a 500 μm capillary, a slug flow pattern was realized which allowed for superior mass transfer and light transparency within a thin solvent layer. These features subsequently gave higher conversion rates and isolated yields.
Fast, solvent-free and hydrogen-bonding-mediated asymmetric Michael addition in a ball mill by Yi-Feng Wang; Ru-Xiang Chen; Ke Wang; Bin-Bin Zhang; Zhao-Bo Li; Dan-Qian Xu (893-895).
The chiral squaramide derivatives as hydrogen bonding catalyst for the Michael addition reactions of 1,3-dicarbonyl compounds to nitroolefins under solvent-free conditions was developed using a planetary ball mill. High yields, high enantioselectivities and shorter reaction times were achieved with low catalyst loading.
Patterned growth of nanocrystalline silicon thin films through magnesiothermic reduction of soda lime glass by Deniz P. Wong; Hsiang-Ting Lien; Yit-Tsong Chen; Kuei-Hsien Chen; Li-Chyong Chen (896-900).
A low-cost and green method of producing nanocrystalline silicon thin films is presented. Using a magnesiothermic reduction process, we have successfully converted the surface of soda lime glass directly into silicon thin film. Furthermore, by varying reaction time, the amount of silicon produced in thin film form (or layer thickness) can be controlled. The nanocrystalline silicon thin films on glass were characterized using scanning electron microscopy, energy dispersive spectroscopy and Raman spectroscopy. Finally, the optical properties of the thin films derived at different reaction times were also measured. The band gaps of the synthesized thin films were within the range of 2.3–2.5 eV.
Synthesis of novel fused heterocycle-oxa-aza-phenanthrene and anthracene derivatives via sequential one-pot synthesis in aqueous micellar system by Madhulika Srivastava; Jaya Singh; Shyam B. Singh; Kamleshwar Tiwari; Vijay K. Pathak; Jagdamba Singh (901-905).
Oxa-aza-phenanthrene and anthracene derivatives which contain a bridgehead nitrogen are synthesized in an aqueous micellar system. The synthetic route is easy and yield is excellent. In this proposed method, solvent, base and surfactant are optimized and the best result was obtained by DBU in water with surfactant CTAB. All synthesized molecules are new. This method is an efficient, viable and sequential one pot synthetic route for the construction of desired product.
Pd–sodium carboxymethyl cellulose nanocomposites display a morphology dependent response to hydrogen gas by Jianli Zou; K. Swaminathan Iyer; Colin L. Raston (906-908).
Hydrogen reduction of H2PdCl4 in the presence of sodium carboxymethyl cellulose (SCMC) in dynamic thin films on a microfluidic spinning disc platform affords Pd–SCMC nano-structures. The morphology of Pd nanocomposites changed from well-connected nano-rosettes to disconnected agglomerates with an increase in SCMC concentration. These nanocomposites were drop cast on interdigitated electrodes (IDEs) to afford sensors for hydrogen gas, with a decrease and increase response in current for nano-rosettes and agglomerates structures, respectively.
Racemic and diastereoselective construction of indole alkaloids under solvent- and catalyst-free microwave-assisted Pictet–Spengler condensation by Mouhamad Jida; Olivier-Mohamad Soueidan; Benoit Deprez; Guillaume Laconde; Rebecca Deprez-Poulain (909-911).
An environment-friendly high-yielding method for the racemic and asymmetric diastereoselective preparation of indole alkaloids via Pictet–Spengler reaction is reported. The reaction proceeds with short reaction times under solvent-free and microwave-irradiation conditions.
Ligand-free copper-catalyzed coupling of nitroarenes with arylboronic acids by Jilei Zhang; Jiuxi Chen; Miaochang Liu; Xingwang Zheng; Jinchang Ding; Huayue Wu (912-916).
The first example of copper-catalyzed coupling of nitroarenes with arylboronic acids was developed, providing diaryl ethers in moderate to excellent yields. The efficiency of this reaction was demonstrated by compatibility with a wide range of groups. Moreover, the rigorous exclusion of air/moisture is not required in these transformations. Thus, the method represents a simple and facile procedure to access diaryl ethers. Preliminary mechanistic experiments using deuterium labeling showed that the oxygen atom was derived from water.
Synthesis and analytical applications of photoluminescent carbon nanodots by Pin-Che Hsu; Zih-Yu Shih; Chia-Hsin Lee; Huan-Tsung Chang (917-920).
We have developed a simple approach for the preparation of carbon nanodots (C-dots) from coffee grounds. As-prepared C-dots have an average diameter of 5 ± 2 nm, of which quantum yield is 3.8%. We have validated the practicality of C-dots for cell imaging and surface-assisted laser desorption/ionization-mass spectrometry (SALDI-MS) of angiotensin I and insulin.
Efficient and practical transition metal-free catalytic hydration of organonitriles to amides by Tao Tu; Zhixun Wang; Zelong Liu; Xike Feng; Qingyi Wang (921-924).
K2CO3 can act as an efficient catalyst for the hydration of organonitriles in aqueous conditions assisted by microwave irradiation, which represents an inexpensive, practical, atom-economical, and straightforward transition metal-free protocol to various amides.
An efficient recyclable peroxometalate-based polymer-immobilised ionic liquid phase (PIILP) catalyst for hydrogen peroxide-mediated oxidation by Simon Doherty; Julian G. Knight; Jack R. Ellison; David Weekes; Ross W. Harrington; Christopher Hardacre; Haresh Manyar (925-929).
A linear cation-decorated polymeric support with tuneable surface properties and microstructure has been prepared by ring-opening metathesis polymerisation (ROMP) of a pyrrolidinium-functionalised norbornene-based monomer with cyclooctene. The derived peroxophosphotungstate-based polymer-immobilised ionic liquid phase (PIILP) catalyst is an efficient and recyclable system for the epoxidation of allylic alcohols and alkenes, with only a minor reduction in performance on successive cycles.
Graphite oxide as an efficient and durable metal-free catalyst for aerobic oxidative coupling of amines to imines by Hai Huang; Jun Huang; Yong-Mei Liu; He-Yong He; Yong Cao; Kang-Nian Fan (930-934).
Graphite oxide was found to be a highly efficient, reusable and cost-effective heterogeneous catalyst for the direct metal-free transformation of amines to afford the corresponding imines under mild and neat conditions with molecular oxygen as the terminal oxidant. This method is simple, economic and environmentally benign, resulting in practical advantages for the convenient synthesis of imines and their derivatives.
Tunable copper-catalyzed chemoselective hydrogenolysis of biomass-derived γ-valerolactone into 1,4-pentanediol or 2-methyltetrahydrofuran by Xian-Long Du; Qing-Yuan Bi; Yong-Mei Liu; Yong Cao; He-Yong He; Kang-Nian Fan (935-939).
Direct conversion of γ-valerolactone, which is one of the most significant cellulose-derived compounds, into 1,4-pentanediol was carried out by chemoselective hydrogenolysis catalyzed by a simple yet versatile copper–zirconia catalyst. Depending on the reaction conditions, 2-methyltetrahydrofuran could also be obtained in excellent yields.
New aspects for biomass processing with ionic liquids: towards the isolation of pharmaceutically active betulin by Anna K. Ressmann; Katharina Strassl; Peter Gaertner; Bin Zhao; Lasse Greiner; Katharina Bica (940-944).
By utilising ionic liquids the pharmaceutically active triterpene betulin can be extracted from biomass with significantly improved extraction yield and purity. The recovery of the ionic liquid 1-ethyl-3-methylimidazolium acetate via azeotropic distillation of EtOH/H2O was successfully demonstrated.
Microwave-assisted synthesis of 2,3-dihydropyrido[2,3-d]pyrimidin-4(1H)-ones catalyzed by DBU in aqueous medium by Liupan Yang; Daxin Shi; Shu Chen; Hongxin Chai; Danfei Huang; Qi Zhang; Jiarong Li (945-951).
A clean green, efficient and facile protocol was developed for the synthesis of a series of 2,3-dihydropyrido[2,3-d]pyrimidin-4(1H)-ones in water with good yield by the reaction of 2-amino-nicotinonitriles with carbonyls catalyzed by DBU under microwave irradiation. The DBU–H2O system can be recycled five times without activity loss.
Industrial commitment to green and sustainable chemistry: using renewable materials & developing eco-friendly processes and ingredients in cosmetics by Michel Philippe; Blaise Didillon; Laurent Gilbert (952-956).
Integrating green chemistry principles into the development of new processes or ingredients and the re-evaluation of existing processes and ingredients is a pivotal element of sustainable development. The aim of this article is to provide a brief description of how L'Oréal, a leading specialist in cosmetic products, is committed to this objective. This commitment is founded on corporate social responsibility (CSR) based on the respect for the five axes of vigilance as shown below, thus allowing analysis throughout the lifecycle of products. The approach of the group regarding the use of renewable raw materials, the development of environmentally-friendly processes and the introduction of green indicators will be presented in more detail later. To illustrate how a green process is implemented we have chosen a recent development, “C-glycosylation in water”, as well as an earlier example, “ceramide synthesis from renewable raw materials” to demonstrate long-term commitment.
Catalyst-free approach for solvent-dependent selective oxidation of organic sulfides with oxone by Bing Yu; An-Hua Liu; Liang-Nian He; Bin Li; Zhen-Feng Diao; Yu-Nong Li (957-962).
Selective oxidation of sulfides was successfully performed by employing oxone (2KHSO5·KHSO4·K2SO4) as oxidant without utilization of any catalyst/additive under mild reaction conditions. Notably, the reaction can be controlled by the chosen solvent. When ethanol was used as the solvent, sulfoxides were obtained in excellent yield; the reaction almost exclusively gave the sulfone in water. Furthermore, this protocol worked well for various sulfides to the corresponding sulfoxides in ethanol or sulfones in water.
Electrochemical oxidation of 4-substituted urazoles in the presence of arylsulfinic acids: an efficient method for the synthesis of new sulfonamide derivatives by Fahimeh Varmaghani; Davood Nematollahi; Shadpour Mallakpour; Roya Esmaili (963-967).
Electrochemical synthesis of some new sulfonamide derivatives was carried out via the electrooxidation of 4-substituted urazoles in the presence of arylsulfinic acids. The results show that electrogenerated 4-alkyl-4H-1,2,4-triazole-3,5-diones participated in a Michael-type reaction with arylsulfinic acids and, via an “electron transfer + chemical reaction” (EC) mechanism, were converted to the corresponding sulfonamide derivatives. In this work, some new sulfonamide derivatives with high yields in aqueous solutions, without toxic reagents and solvents at a carbon electrode using an environmentally friendly novel method, are provided.
Biogenic synthesis of photocatalytically active Ag/TiO2 and Au/TiO2 composites by Weibin Liang; Tamara L. Church; Andrew T. Harris (968-975).
In this work, spherical Ag and Au nanoparticles, primarily below 10 nm in diameter, were synthesised by contacting biological extracts from the vascular plant Citrus limon with aqueous Au3+ and Ag+ solutions at ambient temperature. The chemical constituents of the plant extract acted as reducing, capping and stabilising agents, and nanoparticle size and shape could be tuned by adjusting the pH of the extract suspension. Au nanoparticles synthesised at pH = 7 and Ag nanoparticles synthesised at pH = 11 were monodisperse and well-defined. Thin films of these Au and Ag nanoparticles were coated onto TiO2 by colloidal deposition and the resulting composites were tested as catalysts for the degradation of an organic dye. 1 wt% Au/TiO2 and Ag/TiO2 composites were at least as active as M/TiO2 composites prepared by reduction with NaBH4.
Single-step catalytic liquid-phase hydroconversion of DCPD into high energy density fuel exo-THDCPD by M. G. Sibi; Bhawan Singh; R. Kumar; C. Pendem; A. K. Sinha (976-983).
Hydroconversion of dicyclopentadiene (DCPD) into high energy density jet propellant JP-10 has been successfully achieved with a greener single-step route over supported gold catalyst. The physicochemical properties of the catalysts were studied with XRD, SEM, TEM, N2-adsorption, NH3-TPD. The influence of reaction conditions like temperature, pressure, time etc. were studied in detail. The studies reveal that pressure and temperature play crucial roles in the reaction. Moderate acid sites in the catalysts are chiefly involved in isomerization and gold catalyzes hydrogenation of the intermediates. Analysis of the product stream at different intervals indicates a dissociation–recombination mechanism for the reaction. Reusability of the catalyst was tested by conducting five runs with the same catalyst. Even after the fifth run, the catalyst retains relatively high conversion and selectivity to exo-tetrahydrodicyclopentadiene (exo-THDCPD).
CeO2-catalysed one-pot selective synthesis of esters from nitriles and alcohols by Masazumi Tamura; Takuya Tonomura; Ken-ichi Shimizu; Atsushi Satsuma (984-991).
Thirteen kinds of metal oxides were tested for one-pot selective synthesis of esters from nitriles and alcohols. Ceria (CeO2) showed more than two orders of magnitude higher activity than the other oxides. CeO2 acted as a reusable and effective catalyst for the ester synthesis from various nitriles and alcohols under neutral and solvent-free conditions at 160 °C. This method provides a rare example for the synthesis of heteroaromatic esters, which have been difficult to synthesize by conventional catalytic esterification methods. Valuable esters such as picolinic acid alkyl esters and niacin benzyl esters were synthesized, demonstrating a practical aspect of the present method. Kinetic studies suggested the following reaction mechanism: (1) H2O and ROH dissociate on CeO2, (2) nucleophilic attack of hydroxyl species (OHδ−) to the adsorbed nitrile on CeO2, leading to the formation of the primary amide, (3) nucleophilic attack of alkoxide species (ORδ−) to the amide as the rate-limiting step.
Silica-supported 5-(pyrrolidin-2-yl)tetrazole: development of organocatalytic processes from batch to continuous-flow conditions by Olga Bortolini; Lorenzo Caciolli; Alberto Cavazzini; Valentina Costa; Roberto Greco; Alessandro Massi; Luisa Pasti (992-1000).
5-(Pyrrolidin-2-yl)tetrazole functionalized silica prepared by photoinduced thiol–ene coupling is packed into a short stainless steel column. The resulting packed-bed microreactor is conveniently heated to perform environmentally benign continuous-flow aldol reactions with good stereoselectivities, complete conversion efficiencies, and long term stability of the packing material.
Towards rational molecular design for reduced chronic aquatic toxicity by Adelina M. Voutchkova-Kostal; Jakub Kostal; Kristin A. Connors; Bryan W. Brooks; Paul T. Anastas; Julie B. Zimmerman (1001-1008).
The routine rational design of commercial chemicals with minimal toxicological hazard to humans and the environment is a key goal of green chemistry. The development of such a design strategy requires an understanding of the interrelationships between physical–chemical properties, structure, mechanisms and modes of action. This study develops property-based guidelines for the design of chemicals with reduced chronic aquatic toxicity to multiple standardized species and endpoints by exploring properties associated with bioavailability, narcotic toxicity and reactive modes of action, such as electrophilic interactions. Two simple properties emerge as key parameters that distinguish chemicals in the Low EPA level of concern to three aquatic species from those in the High level of concern – octanol–water partition coefficient, (log Po–w) and ΔE (LUMO–HOMO energy gap). Physicochemical properties were predicted using Schrodinger's QikProp, while frontier orbital energies were determined based on AM1 and DFT calculations using Gaussian03. Experimental toxicity data used consisted of chronic toxicity thresholds (NOEC) for Daphnia magna reproduction (317 compounds, 504 h-assay) and Oryzias latipes (Japanese medaka, 122 compounds in 336, 504 and 672 h assays) survival, and Pseudokirchneriella subcapitata, a green algae model (392 compounds). Results indicate that 92% of compounds of Low chronic concern have log Po–w values < 2 and ΔE > 9 eV. Chronically safe compounds to P. subcapitata meet similar criteria – 80% have log Po–w values < 3 and ΔE greater than 9 eV. Our work proposes design guidelines that can be used to significantly increase the probability that a chemical will have low chronic toxicity, based on the endpoints evaluated, to the three diverse aquatic species studied, and potentially to other aquatic species.
Porous glass beads as a new adsorbent to remove sulfur-containing compounds by C. Shen; Y. J. Wang; J. H. Xu; Y. C. Lu; G. S. Luo (1009-1015).
This paper explores porous glass beads as a pollutant-free-prepared, low-cost, and recyclable adsorbent for desulfurization. Porous glass beads with a specific surface area, pore volume, and mean pore diameter of 162.6 m2 g−1, 0.26 cm3 g−1, and 6.34 nm, respectively, were obtained by subcritical water treatment. The effects of the surface chemistry of the adsorbent and the structure of the organosulfur molecules on adsorption capacity were studied; the software, Materials Studio, was used to calculate the interactions between the surface of the glass beads and the sulfur-containing compounds. Compared with these porous glass beads, two other kinds of porous glass beads modified by hexamethyldisilazane and hydrochloric acid, respectively, showed much lower adsorptive capacity for dibenzothiophene, indicating the metal ions contained in the glass played an important role during the adsorption; the capacities of the porous glass beads for benzothiophene, dibenzothiophene, and 4,6-dimethyldibenzothiophene were 6.47 ± 0.09, 8.58 ± 0.09, and 11.20 ± 0.08 mg(S) gadsorbent−1, respectively, corresponding to the simulation results. The adsorptive capacity for dibenzothiophene decreased with the increase of temperature but increased with the increase of initial concentration, the highest capacity of 10.29 ± 0.11 mg(S) gadsorbent−1 was obtained at 303 K with the initial concentration of 565 ppmw(S). Spent adsorbent can be regenerated by heating at high temperature, and the adsorptive capacity only decreased about 3.38% after five cycles. Experimental results and the computer simulations indicate that polar interactions between the surface and sulfur-containing compounds dominated the adsorption.
Copper-catalyzed highly efficient aerobic oxidative synthesis of imines from alcohols and amines by Qiang Kang; Yugen Zhang (1016-1019).
A highly efficient and green tandem imine synthesis from alcohol and amine with molecular oxygen as oxidant was achieved by using a remarkable low catalyst-loading, with a commercially available and environmentally benign copper catalyst.
Surprising metal binding properties of phytochelatin-like peptides prepared by protease-catalysis by Kodandaraman Viswanathan; Mark H. Schofield; Iwao Teraoka; Richard A. Gross (1020-1029).
Phytochelatins (PCs) consist of alternating glutamic acid and cysteine residues ([γGlu–Cys]–Xaa) and are responsible for binding to heavy metals for cellular metal homeostasis and detoxification. This paper describes the papain-catalyzed synthesis of cysteine-rich peptides as potential PC mimics. By adjusting the feed ratio of l-cysteine ethyl ester (l-Et-Cys) and l-glutamic acid diethyl ester (l-(Et)2-Glu) followed by de-esterification, α-linked oligo(l-Glu-co-47%l-Cys) was prepared that closely matches the 1 : 1 l-Glu-to-l-Cys molar ratio of PC peptides. Plots of absorbance difference as a function of total metal-to-peptide ([M]total–[P]total) molar ratio were constructed for titrations with Zn(ii), Cd(ii), Co(ii) and Ni(ii). A series of equations were generated to evaluate dissociation constants and the number of metal ions per peptide molecule in metal–peptide complexes. All of the four complexes have on average two oligo(l-Glu-co-47%l-Cys) molecules per divalent cation. The binding of metals to oligo(l-Glu-co-47%l-Cys) weakens in the order of Cd(ii) > Zn(ii) > Ni(ii) > Co(ii), the same trend observed for [(γGlu–Cys)4]–Gly. The peptide quantity required to sequester a given amount of Zn(ii) and Cd(ii) when using oligo(l-Glu-co-47%l-Cys) is only about twice as much as the quantity for perfect sequence peptide (γGlu–Cys)2–Gly. Furthermore, when [M]total is low, random oligo(l-Glu-co-47%l-Cys) sequesters much higher fractions of Co(ii) and Ni(ii) than does (γGlu–Cys)2–Gly. Results from this work provide the first evidence that, in some cases, uniform peptides synthesized by tedious solid or liquid phase peptide synthetic methods, can be replaced with peptide mixtures prepared by facile protease-catalyzed peptide synthetic methods without substantial loss in product performance.
Glycerol as a recyclable solvent for copper-catalyzed cross-coupling reactions of diaryl diselenides with aryl boronic acids by Vanessa G. Ricordi; Camilo S. Freitas; Gelson Perin; Eder J. Lenardão; Raquel G. Jacob; Lucielli Savegnago; Diego Alves (1030-1034).
We describe herein the use of glycerol as the solvent in the copper-catalyzed cross-coupling reaction of diaryl diselenides with arylboronic acids using CuI and DMSO as additive. This cross-coupling reaction was performed with diaryl diselenides and arylboronic acids bearing electron-withdrawing and electron-donating groups, affording the corresponding diaryl selenides in good to excellent yields. The glycerol–CuI mixture can be directly reused for further cross-coupling reactions.
Efficient hydrogen production from bio-butanol oxidative steam reforming over bimetallic Co–Ir/ZnO catalysts by Weijie Cai; Narcis Homs; Pilar Ramirez de la Piscina (1035-1043).
This paper reports, for the first time, hydrogen production from oxidative steam reforming of a bio-butanol raw mixture (n-butanol–acetone–ethanol = 6 : 3 : 1, mass ratio). The process was carried out over new bimetallic Co–Ir/ZnO catalysts using air as an oxidant. The behaviour of bimetallic catalysts was compared with that of monometallic ones. Bimetallic catalyst Co–0.3Ir/ZnO (7 wt% Co, 0.3 wt% Ir) showed higher catalytic performance than monometallic samples, giving higher hydrogen concentration in the outlet gas and lower by-product formation. Moreover, the addition of 0.3 wt% Ir to Co–ZnO prevented the formation of carbon deposits and decreased their degree of graphitization. Addition of more iridium (1 wt% Ir) did not improve the catalytic behaviour. Several techniques, such as N2 adsorption, XRD, TPR, HRTEM, TG-DTG, XPS and Raman spectroscopy, were used for characterizing the fresh and used catalysts.
On the double role of surfactants as microalga cell lysis agents and antioxidants extractants by G. Ulloa; C. Coutens; M. Sánchez; J. Sineiro; J. Fábregas; F. J. Deive; A. Rodríguez; M. J. Núñez (1044-1051).
An integrated process based on the concomitant role of non-ionic surfactants as cell disrupters and organic extractants of intracellular antioxidants is proposed for the first time in this work. The lytic effect of two common families of surfactants on the cell walls of the microalga Tetraselmis suecica has been initially evaluated. The antioxidant extraction based on aqueous two-phase systems (ATPS) was proposed using different potential salting out agents such as sodium inorganic and organic salts in aqueous solutions of the selected surfactants. The extraction efficiency was ascertained for the most representative biomolecules previously detected in this microalga: α-tocopherol, β-carotene and gallic acid. The viability of the process was checked in real lyophilized microalga samples, yielding higher antioxidant activity than that provided by an ultrasound-based conventional method.
High performance membranes based on ionic liquid polymers for CO2 separation from the flue gas by Pei Li; D. R. Paul; Tai-Shung Chung (1052-1063).
Three vinyl functionalized imidazolium based room-temperature ionic liquids (RTILs): 1-vinyl-3-ethylimidazolium dicyanamide ([veim][dca]), 1-vinyl-3-butylimidazolium dicyanamide ([vbim][dca]) and 1-vinyl-3-heptylimidazolium dicyanamide ([vhim][dca]) were synthesized and UV-polymerized to form free standing membranes. The pure gas permeabilities of CO2 and N2 of these newly developed membranes acquired at 1 atm 35 °C increased with an increase in the number of N-alkyl group in the monomers but their ideal CO2–N2 selectivities decreased. The three vinyl functionalized monomers were blended with three free RTILs: 1-ethyl-3-methylimidazolium dicyanamide ([emim][dca]), 1-ethyl-3-methylimidazolium tetracyanoborate ([emim][B(CN)4]) and 1-ethyl-3-methylimidazolium tetrafluoroborate ([emim][BF4]) and subsequently subjected to UV-polymerization to form the poly(RTIL)–RTIL composite membranes. The incorporation of free RTILs not only significantly increases the CO2 permeability but also greatly improves the CO2–N2 selectivity. The best separation performance is achieved for the poly([vbim][dca])–[emim][B(CN)4] (1 : 2) and poly([vbim][dca])–[emim][dca] (1 : 2) composite membranes, which have CO2 permeabilities of 340 and 273 barrers and CO2–N2 selectivities of 42 and 53, respectively, at 1 atm 35 °C. The mixed gas permeabilities of these two composite membranes are 297 and 253.5 barrers with corresponding CO2–N2 selectivities of 38.8 and 50.6, respectively, using a 50 : 50 CO2–N2 mixed gas at 2 atm 35 °C. These two composite membranes have separation performance very close to the 2008 “Robeson Upper Bound”, suggesting their potential for industrial applications, especially for the post-combustion flue gas treatment.
Cu–ZrO2 nanocomposite catalyst for selective hydrogenation of levulinic acid and its ester to γ-valerolactone by Amol M. Hengne; Chandrashekhar V. Rode (1064-1072).
Several copper based catalysts were prepared, characterized and evaluated for the hydrogenation of levulinic acid and its methyl ester. Among these, nanocomposites of Cu–ZrO2 and Cu–Al2O3 quantitatively catalyzed the hydrogenation of levulinic acid and its methyl ester to give 90–100% selectivity to γ-valerolactone in methanol and water respectively. Both the Cu–ZrO2 and Cu–Al2O3 nanocomposites were prepared by the co-precipitation method using mixed precursors under controlled conditions. XRD results showed that the main active phase of the reduced Cu–ZrO2 catalyst was metallic copper and particle size was found to be of 10–14 nm by HRTEM. The active metal leaching was at a maximum for the Cu–Al2O3 catalyst in a water medium due to the formation of a copper–carboxylate complex that was blue in colour. Surprisingly, copper leaching was completely suppressed in the case of the Cu–ZrO2 catalyst in methanol in spite of the substrate loading was increased from 5 to 20% w/w. The excellent recyclability of the Cu–ZrO2 catalyst with complete LA conversion and >90% GVL selectivity makes it a sustainable process having a commercial potential.
One-pot synthesis of lignin-stabilised platinum and palladium nanoparticles and their catalytic behaviour in oxidation and reduction reactions by Francesca Coccia; Lucia Tonucci; Domenico Bosco; Mario Bressan; Nicola d'Alessandro (1073-1078).
A one-pot green method to synthesise Pt and Pd nanoparticles is reported. Two natural aromatic polymers, lignin and fulvic acid, were used as both reducing and stabilising agents at moderate temperature (80 °C) in water and under aerobic conditions. Full characterisation was performed using TEM, UV-vis, XRD, 195Pt and 1H NMR, FT-IR and GC-MS techniques. In the TEM images, we observed spherical nanoparticles of diameters in the range of 16 nm to 20 nm, in the case of Pd, and smaller ones of not so well defined shapes for Pt. GC-MS of the organic fractions formed during the preparation of the nanoparticles showed defined amounts of vanillin, a well known degradation product of these polymers. This finding indicates that the active participation of lignins and fulvic acids in the metal reduction step. The catalytic activity of the nanoparticles was tested for the NaBH4 reduction of 4-nitrophenol and for the aerobic oxidation of alcohols, reactions that are always conducted under green conditions. Both Pt and Pd nanoparticles show good catalytic activity in the reduction reaction, while in the aerobic oxidation reaction only the Pt nanoparticles were effective.
Soaking of pine wood chips with ionic liquids for reduced energy input during grinding by Agnieszka Brandt; James K. Erickson; Jason P. Hallett; Richard J. Murphy; Antje Potthast; Michael J. Ray; Thomas Rosenau; Michael Schrems; Tom Welton (1079-1085).
Ionic liquids are of great interest as potential solvents/catalysts for the production of fuels and chemicals from lignocellulosic biomass. Attention has focused particularly on the pretreatment of lignocellulose to make the cellulose more accessible to enzymatic hydrolysis. Any biomass processing requires a reduction in the size of the harvested biomass by chipping and/or grinding to make it more amenable to chemical and biological treatments. This paper demonstrates that significant energy savings can be achieved in the grinding of pine wood chips when the ionic liquid is added before the grinding operation. We show that this is due to the lubricating properties of the ionic liquids and not to physico-chemical modifications of the biomass. A brief impregnation of the chipped biomass results in higher savings than a longer treatment.
Chemoselective reduction of a nitro group through transfer hydrogenation catalysed by Ru0-nanoparticles stabilized on modified Montmorillonite clay by Podma Pollov Sarmah; Dipak Kumar Dutta (1086-1093).
Ru0-nanoparticles of approximately 5 nm size were generated by incipient impregnation of RuCl3 into the nanopores of the acid activated Montmorillonite clay followed by polyol reduction. Acid activation of the clay increases the surface area by generating nanopores (0–10 nm), which act as a host and stabilize nanoparticles in the pores. The generated Ru0-nanoparticles exhibit inter-planar lattice fringe spacing of 0.21 nm of the face centered cubic lattice of Ru0 crystals, and show efficient catalytic activity in the chemoselective transfer hydrogenation reduction of substituted nitrobenzenes to corresponding anilines with high yield of conversion (56–97%) and selectivity (91–100%) depending upon the nature of the substituents. The reactions were carried out in the presence of isopropanol, which served as the solvent as well as the reductant. The catalysts were found to be active for several catalytic runs.
Selecting and designing chemicals: application of a mass balance model of chemical fate, exposure and effects in the environment by Simanga Gama; Donald Mackay; Jon A. Arnot (1094-1102).
The factors that are conventionally considered when selecting or designing more environmentally benign chemicals are described and discussed. A modelling strategy is described by which the environmental behaviour of chemicals can be compared and changes in molecular structure evaluated with the objective of contributing to this process. This is accomplished using a mass balance model for chemical fate, exposure and effects in an evaluative environment that depicts the likely environmental behavior of the substance and includes a mechanistic bioaccumulation and food web component, yielding estimates of both human and ecological exposures to the chemical. These exposures can be compared with levels known to exert toxic effects. The strategy thus provides a holistic characterization of chemical fate, persistence, bioaccumulation, exposure, proximity to levels of toxic concern, potential for long range transport and the effect of quantity of chemical released under steady-state conditions. Substances can be readily compared and the effects of proposed changes in molecular structure and hence properties can be evaluated. A key component is the use of the concepts of chemical fugacity and activity for describing the chemical's environmental distribution and potential to exert toxicity. The concept is applied to organic solvents, including alkanes, aromatics, halogenated aromatics and nitrogen-containing compounds.
Highly regioselective di-tert-amylation of naphthalene over reusable H-mordenite zeolite by Keith Smith; Alaa K. H. Al-Khalaf; Gamal A. El-Hiti; Samuel Pattisson (1103-1110).
Highly regioselective di-tert-amylation of naphthalene using different alcohols can be achieved over a H-mordenite (HM) zeolite. For example, the tert-amylation of naphthalene using tert-amyl alcohol in cyclohexane over HM (Si/Al = 10) zeolite has been optimised to give a 70% yield of 2,6-dialkylnaphthalenes, of which 2,6-di-tert-amylnaphthalene was produced in 46% yield along with 2-tert-amyl-6-tert-butylnaphthalene (23%) and 2,6-di-tert-butylnaphthalene (1%). This has been achieved by varying the reaction time, temperature, pressure and amounts of tert-amyl alcohol and zeolite. No 2,7-dialkylnaphthalenes were seen under the conditions tried. The zeolites can be easily regenerated by heating and then reused.
Ester as a blocking group for palladium-catalysed direct forced arylation at the unfavourable site of heteroaromatics: simple access to the less accessible regioisomers by Lu Chen; Christian Bruneau; Pierre H. Dixneuf; Henri Doucet (1111-1124).
The use of esters as blocking groups at the C2 position on a range of 3-substituted 5-membered ring heteroaromatics such as thiophenes or furans, allows control of the regioselectivity for the palladium-catalysed direct arylation at C5-H. This arylation can be followed by easy decarboxylation. This method allows sequential catalytic C5 arylation, decarboxylation and catalytic C2 arylation reactions.
Solvent-free bromination reactions with sodium bromide and oxone promoted by mechanical milling by Guan-Wu Wang; Jie Gao (1125-1131).
New solvent-free brominations of 1,3-dicarbonyl compounds, phenols, various alkenes including chalcones, azachalcones, 4-phenylbut-3-en-2-one, methyl cinnamate, styrene and 1,3-cyclohexadiene were efficiently achieved by employing sodium bromide and oxone under mechanical milling conditions. The brominated products were obtained in good to excellent yields.
Panorama of sustainable solvents using the COSMO-RS approach by Laurianne Moity; Morgan Durand; Adrien Benazzouz; Christel Pierlot; Valérie Molinier; Jean-Marie Aubry (1132-1145).
Recent regulations have banned numerous common organic solvents that have been recognized as hazardous to human health and environment. There is thus a pressing need for alternatives, often called “green” or “sustainable” solvents, which have a good HSE (Health Safety Environment) profile and are preferably obtained from the biomass feedstock. A number of such green solvents are already on the market or under advanced development and have been listed in this work. To use this set of solvents as effective alternatives, a tool is needed to compare their physico–chemical properties to the ones of the solvents they are supposed to replace. The COnductor-like Screening MOdel for Real Solvents (COSMO-RS) approach was used to model the solvents, which were located in a pseudo 3D-space thanks to Principal Components Analysis and clustering procedures. This approach had already been successfully applied to the classification of classical organic solvents into ten families in which the green solvents have been positioned. This pseudo 3D-representation of green solvents helps in the search of potential alternatives to a questionable solvent. It also sheds light on paucity or even a complete lack of green solvents in some families (e.g. strong electron pair donor bases). There is thus a need to develop new green solvents with the prerequisite properties. As the COSMO-RS approach can be applied to almost any potential candidate, it could be a powerful tool for the design in silico of new sustainable solvents.
Asymmetric hydrogenation of CC double bonds using Rh-complex under homogeneous, heterogeneous and continuous mode conditions by Szabolcs Balogh; Gergely Farkas; József Madarász; Áron Szöllősy; József Kovács; Ferenc Darvas; László Ürge; József Bakos (1146-1151).
A green process for enantioselective hydrogenation of dehydroamino acid derivatives and dimethyl itaconate with a rhodium catalyst modified by a new phosphine–phosphoramidite has been developed providing 97.7–99.8% enantioselectivity in green solvents such as ethylene carbonate and propylene carbonate. The l-DOPA precursor was obtained by simple filtration in 71% yield with 99.5% ee. Dimethyl itaconate was hydrogenated under solvent-free condition at 50 °C with 98.7% ee. The new rhodium complex was heterogenized on a mesoporous Al2O3 support using phosphotungstic acid (PTA) as an anchoring agent and tested in heterogeneous batch and flow reaction modes. The supported catalyst was reused eight times in the batch mode with over 97% ee and used over 12 hours in the flow reaction mode with an average of 97% ee in the asymmetric hydrogenation reaction of (Z)-α-acetamidocinnamic acid methyl ester.
Water as an additive to enhance the ring opening of naphthalene by Qian Wang; Honglei Fan; Suxiang Wu; Zhaofu Zhang; Peng Zhang; Buxing Han (1152-1158).
Use of water as a reaction medium or additive to enhance reaction efficiency is an important topic in green chemistry, and ring opening and contraction reactions of aromatics are crucial for upgrading diesels. In this work, we investigated the effect of water on the yields of ring opening and contraction reactions of naphthalene. A series of catalysts, such as Rh2O3/HY zeolite, Mo–Ni oxide and their physical mixtures, were used as the catalysts. The influences of the amount of water, hydrogen pressure, reaction temperature and reaction time on the yields of the ring opening and contraction products (ROCP) were studied. It was found that Rh2O3/HY and Mo–Ni oxide showed an excellent synergistic effect for catalyzing the reaction, and water could be used as a green and efficient additive for enhancing the yield of the ROCP. At the optimized conditions, the yield of the ROCP could be as high as 63.3%. The mechanism for the effect of water on the reactions was discussed on the basis of control experiments.
Catalyst-free and highly selective electrophilic mono-fluorination of acetoacetamides: facile and efficient preparation of 2-fluoroacetoacetamides in PEG-400 by Jingjing Bi; Zhiguo Zhang; Qingfeng Liu; Guisheng Zhang (1159-1162).
Series of α-mono-fluorinated acetoacetamides were synthesized under mild condition with industrialized Selectfluor as the F+ source in PEG-400. The approach avoided the use of base or metal catalyst, and most of cases proceeded in nearly quantitative conversions regardless of the electronic nature of the diversity substituent.
Bio-based chiral dopants having an isohexide skeleton for cholesteric liquid crystal materials by Seunghan Shin; Jae Won Seo; Jin Ku Cho; Sangyong Kim; Jaeryung Cha; Myoung Seon Gong (1163-1167).
Chiral dopants were synthesized from bio-based epimeric isohexides (glucose-derived isosorbide and mannose-derived isomannide) and their phase transition behaviors and abilities for developing cholesteric liquid crystal (CLC) films were examined with a consideration of the core structure. In spite of lower reactivity of the endo hydroxy group of isomannide caused by the steric hindrance and intermolecular hydrogen bonding, final synthetic yields of chiral dopants bearing an isomannide core (64.5% for IH-2 and 65.0% for IH-4) did not show conspicuous difference compared with chiral dopants bearing isosorbide (68.4% for IH-1 and 74.0% for IH-3). On the other hand, in phase transition behaviors, chiral dopants bearing an isomannide core showed lower crystalline and melting temperatures than IH-1, IH-3 despite of the same substituents. The helical twisting power (HTP) of chiral dopants bearing isosorbide (IH-1 and IH-3) was higher than that of chiral dopants bearing isomannide (IH-2 and IH-4). The calculated HTPs of IH-1 and IH-3 were 26.6 and 42.1 μm−1, respectively. In the case of IH-3, the helical pitch length of CLC could be adjusted to reflect visible light by controlling its amount and showed best performance in the range 5.0 to 7.0 mol%. In contrast to IH-1 and IH-3, it was found that IH-2 and IH-4 could not induce CLC films that reflect visible light.
Hybrid sol–gel double metal cyanide catalysts for the copolymerisation of styrene oxide and CO2 by Yvonne Dienes; Walter Leitner; Merlin G. J. Müller; Willem K. Offermans; Tobias Reier; Alexander Reinholdt; Thomas E. Weirich; Thomas E. Müller (1168-1177).
Hybrid sol–gel catalysts of zinc hexacyanocobaltate and SiO2 were prepared by co-precipitation of the double metal cyanide with silica. Hybrid catalysts prepared at moderately acidic conditions showed the best performance with respect to activity, selectivity and stability. The hybrid sol–gel materials displayed high catalytic activity for the copolymerisation of styrene oxide and carbon dioxide (up to 650 molSO (molZn h)−1) and high productivity (575 gPolymer gCatalyst−1). They also displayed good selectivity to the polymeric product (80–87%), while only little cyclic styrene carbonate was formed as side product. A detailed electron microscopy study of the hybrid sol–gel materials showed that the active phase consisted of thin platelets containing the metals in a molar ratio nZn/nCo = 2.1, whereby the double metal cyanide was closely associated with silica.
Homogeneous catalytic hydrogenation of long-chain esters by an osmium pincer complex and its potential application in the direct conversion of triglycerides into fatty alcohols by Alberto Acosta-Ramirez; Marcello Bertoli; Dmitry G. Gusev; Marcel Schlaf (1178-1188).
The osmium hydride complexes OsH2(CO)[NH(CH2PiPr2)2] (1) and OsHCl(CO)[NH(CH2PiPr2)2] (2) were evaluated in the catalytic hydrogenation of hexyl octanoate and cis-3-hexenyl hexanoate to alcohols as model substrates for triglycerides. Both complexes achieve full conversion of the saturated ester at 220 °C and 800 psi pressure of hydrogen gas. In the presence of unsaturated substrates, the complexes hydrogenate CC bonds, but are subsequently ineffective in the reduction of the ester moiety. However complex 1 is capable of hydrogenating fully saturated triglycerides (i.e., hardened fats as obtained by separate initial hydrogenation of seed oils using either 1 or 2 or a standard heterogeneous hydrogenation catalyst) giving cetyl and stearyl alcohols as the main products.
One-pot oxidative N-demethylation of tropane alkaloids with hydrogen peroxide and a FeIII-TAML catalyst by Duy D. Do Pham; Geoffrey F. Kelso; Yuanzhong Yang; Milton T. W. Hearn (1189-1195).
The oxidative N-demethylation of tropane alkaloids to their nortropane derivatives has been investigated using H2O2 and an iron(iii) tetraamido macrocycle (FeIII-TAML) catalyst. The yields of the nortropanes were found to be dependent on the amount of H2O2 used in the reaction, the catalyst loading, the nature of the organic co-solvent and the type of tropine substrate. N-Hydroxy-nortropane, N-formyl-nortropane and tropane-N-oxide derivatives were identified as by-products of the reaction. After screening various reaction conditions, the optimised conditions were applied to the N-demethylation of atropine and scopolamine at preparative scales and the desired products, noratropine and norscopolamine, obtained following one pot reactions in good yields and high purity without the need for any chromatographic purification steps.
Creation of spherical carbon nanoparticles and clusters from carbon dioxide via UV dissociation at the critical point by Ortrud Aschenbrenner; Takahiro Fukuda; Takashi Hasumura; Toru Maekawa; Andrew B. Cundy; Raymond L. D. Whitby (1196-1201).
Carbon nanomaterials have become increasingly important for many applications, including sensors, electronics, biomedical materials and functional composites. Currently their production is based on hydrocarbons or graphite and requires very high temperatures. Here we present a method for the synthesis of carbon nanomaterials from carbon dioxide. Unlike previously described methods, our synthesis method works near room temperature. Carbon dioxide is irradiated at its critical point, producing spherical carbon nanoparticles even without the use of a catalyst. We examine the influence of irradiation parameters and different metals and catalysts on the nanocarbon production. Together with analysis of the fluid phase, this allows us to draw some conclusions on the carbon dioxide dissociation mechanism.
Enzymatic hydrolysates of corn stover pretreated by a N-methylpyrrolidone–ionic liquid solution for microbial lipid production by Haibo Xie; Hongwei Shen; Zhiwei Gong; Qian Wang; Zongbao K. Zhao; Fengwu Bai (1202-1210).
In this study, we reported a novel N-methylpyrrolidone (NMP)–1-ethyl-3-methyl imidazolium acetate (EmimAc) mixed solvent (XILs = 0.2, mole fraction of ionic liquids (ILs) in the mixed solution) that can dissolve up to 10 wt% corn stover at 140 °C in 60 min. Physiochemical analysis showed major differences in terms of cellulose crystallinity, compositional distribution and surface morphology between raw corn stover samples and the regenerated materials, indicating that dissolution in the NMP–EmimAc system followed by regeneration with anti-solvents could be used as an effective pretreatment technology. Enzymatic saccharification of the regenerated corn stover afforded an 82.9% total reducing sugars yield and a 60.8% glucose yield within 24 h. The hydrolysates were used, without detoxification, as the carbon sources for the cultivation of Rhodosporidium Toruloides Y4 for lipid production. Glucose and xylose in the hydrolysates were both consumed in our process. In a word, our study reported a novel dissolution pretreatment technology for biomass utilization with outstanding advantages compared with traditional pure ionic liquid processes, such as (I) minimal use of expensive ILs in NMP, and commercially available EmimAc and NMP can be used directly without any further dry purification; (II) high cellulose and hemicellulose regeneration; (III) high enzymatic hydrolysis efficiency of the pretreated sample with full conversion of carbohydrates in less than 24 h; (IV) air-dried corn stover can be used directly (water content = ∼5%); (V) the hydrolysates can be used for further bioconversion and on inhibitory effect was observed. We believe that all of these advantages determine its potential for practical applications.
Incorporation of l-lactide random copolymers with Japanese cypress oil (α-pinene) using supercritical carbon dioxide by Chikara Tsutsumi; Teruyuki Hara; Naohisa Fukukawa; Kazuyuki Oro; Kazuaki Hata; Yuushou Nakayama; Takeshi Shiono (1211-1219).
This study involved the incorporation of useful compounds, such as repellents and antibacterial agents, at high concentrations in l-lactide (l-LA) random copolymers. The amount of α-pinene released in gas from the copolymers was also evaluated. Outstanding controlled release properties were developed using random copolymers of l-lactide (l-LA) with γ-valerolactone (VL), ε-caprolactone (CL), tetramethylene carbonate (TEMC) (1,3-dioxepan-2-one), and 1,5-dioxepan-2-one (DXO) using tin 2-ethyl-hexanoate [Sn(oct)2] as a catalyst at 150 °C for 24 h without solvent. Preparation of controlled release materials was accomplished using α-pinene from Japanese cypress oil and synthetic random copolymers of l-LA with cyclic monomers as base materials under supercritical carbon dioxide (scCO2). Poly(l-LA-ran-VL), poly(l-LA-ran-CL), poly(l-LA-ran-TEMC), and poly(l-LA-ran-DXO), which have lower Tm and ΔHm values than poly(l-LA) were used for the impregnation experiments. The oil content of the copolymers was greater than that in poly(l-LA). The content of oil into poly(l-LA-ran-TEMC) (80 : 20) was 8.1%, 2.1-fold greater than that in poly(l-LA) (Lacea H-100) (H-100), and 1.5-fold greater than that in poly(l-LA) (Lacea H-440) (H-440). Although a previous study showed that 3.2% d-limonene could be incorporated into poly(l-LA-ran-CL) (85 : 15) under the same conditions, results of this experiment showed that 5.8% and 6.6% oil could be incorporated into poly(l-LA-ran-CL) (81 : 19 or 91 : 9), respectively. Results from controlled release experiments demonstrated that the oil content in the polymer decreased upon copolymer degradation for all copolymers. In gas release tests, polymers H-440 and poly(l-LA-ran-VL) (85 : 15) released gas upon hydrolysis. Although the weight loss of H-440 was only 9% at 56 days, the calculated loss of oil in H-440 was 28%.
Entrainer-intensified vacuum reactive distillation process for the separation of 5-hydroxylmethylfurfural from the dehydration of carbohydrates catalyzed by a metal salt–ionic liquid by Zuojun Wei; Yingxin Liu; Dilantha Thushara; Qilong Ren (1220-1226).
As more and more novel catalyst systems are being developed for the dehydration of carbohydrates, especially glucose, an effective way to separate the dehydration product 5-hydroxylmethylfurfural (5-HMF) is also required for industrial manufacturing. In this paper, for the first time, we have developed a process called EIVRD (entrainer-intensified vacuum reactive distillation) to separate 5-HMF from the dehydration solutions of carbohydrates catalyzed by a metal chloride/1-methyl-3-octyl imidazolium chloride ([OMIM]Cl) ionic liquid, in which high vacuity and entrainers were applied to intensify the distillation of 5-HMF as well as the dehydration of fructose or glucose. In such an EIVRD process, the average recoveries of 5-HMF dehydrated from fructose and glucose are around 93% and 88%, respectively. The recycling of the catalyst system in the EIVRD process is so convenient that the recovery and actual yield of 5-HMF is successfully repeated during the whole five recycled reactions.
Back cover (1227-1228).