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New materials supported by Green Chemistry have been receiving widespread attention because they are fulfilling the sustainable development goals (SDGs) agenda, for which clean water development is a top priority. Recently, electrospun nanofibers membranes are being frequently used to decontaminate organic pollutants such as dyes because of their easy operation, flexibility, economic feasibility and high removal efficiency. In the present study, green polyvinyl alcohol-based electrospun nanofibers membranes (PVA NF) were produced at room temperature and applied for efficient capturing methylene blue as a common organic pollutant. A series of experiments were conducted to affirm their catalytic activity. In particular, dye degradation studies were initiated by dissolving a selected amount of Fe (III), H2O2, PVA NF membrane and ultrasound (ULTS). Results showed that ultrasound could generate hydroxyl (•OH) radical and triggers dye removal percentages, which are of significant contribution in terms of peroxide-free Fenton-like catalysis. Finally, this study has proven that electrospun nanofibrous membranes could be a potential economic and efficient carrier for the Fenton catalytic process to capture large amounts of organic pollutants from industrial effluents.

The boosting of greenhouse gas (GHG) emissions into the atmosphere due to anthropogenic activity contributes significantly to climate change. According to the Green Deal by 2050, net zero greenhouse gas emissions must be achieved. Therefore, actions are needed in order to control GHG emissions. The research presents and discusses the optimization of the microalgae biomass cultivation phase and the harvesting process in an advanced membrane photobioreactor (mPBR) with the aim to improve its production for green fuel generation. Experimental activities are carried out by considering Chlorella vulgaris microalgae as photosynthetic microorganism. A dark/light cycle of 12/12 hours was implemented by varying the light intensity from 100 to 300 μmol m-2 s-1. Different L/G rate, by keeping the gas flow rate (G) constant at 100 ml/min and increasing the liquid flow rate recirculation (L) from 500 to 1500 L min-1, has been tested to boost up the productivity of microalgae. Results highlight optimal production of microalgae biomass concentration up to 1.45 g L-1. Then a dynamic membrane module was implemented for the harvesting of the biomass. The work contributes to the field of climate change mitigation actions, by providing useful information to improve green energy production from algae biomass.

The exploration of new biomass sources for energy purposes is increasing. Cultivation of algal biomass for biofuels production through photobioreactor represents an attractive and useful way to obtain clean energy, also thanks to the contribution that the system makes on the reduction of climate change through the recovery and reuse of CO2. However, to prove the complete sustainability of a system the application of a holistic assessment, like Life Cycle Assessment (LCA) methodology, is necessary. To date LCA is applied through different methodologies, which make evaluations and systems difficult to compare and evaluate. Furthermore only few studies are present in the scientific literature that highlight the parameters used for the evaluation of membrane photobioreactors (mPBR). The research presents and discusses the state-of-the-art of the adopted LCA methodologies to assess mPBR, pointing out strengths and weaknesses. Knowledge gap, uncertainties and recommendations are highlighted. Furthermore, a case study LCA application on an advanced mPBR for the CO2 capture and biomass production is presented. The study provides important information to the different scientists involved in the microalgae production sector in a holistic and proactive view in order to maximize its environmental sustainability.

The development of resilient and sustainable cities emerged as a solution to tackle the several challenges arising from the exponential growth of urban areas population worldwide. The implementation of environmental technologies represents a solution to minimize negative impacts of crowded cities on the environment and human health. The research presents and discusses the applications of advanced and innovative cutting edge technologies to develop sustainable, green and resilient cities. The study is carried out by distinguishing environmental technologies (ETs) on four principal sectors: water and greywater, air pollution, municipal solid waste and mobility. For each technology the strengths and weaknesses are analysed and pointed out. The application of the principal technologies evaluated with reference to real cases study of metropolitan area were highlighted. The work contributes to the development of sustainable cities, providing useful information to support urban planners and policymakers in order to minimize environmental pressures and improve the way they operate.

The zinc complex Zn(C6F5)2(toluene) (1) behaves as a very active and selective catalyst in cyclohexene oxide (CHO) polymerization to produce poly(cyclohexene oxide) (PCHO) by the trans-ring-opening of CHO with remarkable TOF values at room temperature. The ring-opening copolymerization (ROCOP) of CO2 with CHO catalysed by 1 yields poly(cyclohexene carbonate) (PCHC) when using benzyl alcohol (BnOH) as an initiator at 120 °C. The 1H NMR monitoring of the in situ reaction of 1 with BnOH highlighted the formation of the dinuclear species [(C6F5)2Zn2(BnO)2 (2) that was isolated and found an active catalyst in the ROCOP of CO2 with CHO in the absence of initiators. Interestingly, PCHCs by 2 in solventless conditions show polydispersity index (Mw/Mn) values close to 2, corresponding to those expected for a single-site catalyst; on the contrary, a broader polydispersity index of the polymer products was found in toluene solution, suggesting the formation of new zinc catalysts during the polymerization reaction.

Metal hydride complexes find widespread application in catalysis and their properties are often understood on the basis of the available crystal structures. However, some catalytically relevant metal hydrides are only spontaneously formed in situ, cannot be isolated in large quantities or crystallised and their structure is therefore ill defined. One such example is the paramagnetic Ti(iii)-hydride involved in homogeneous Ziegler–Natta catalysis, formed upon activation of CpTi(iv)Cl3 with modified methylalumoxane (MMAO). In this contribution, through a combined use of electron paramagnetic resonance (EPR), electron-nuclear double resonance (ENDOR) and hyperfine sublevel correlation (HYSCORE) spectroscopies we identify the nature of the ligands, their bonding interaction and the extent of the spin distribution. From the data, an atomistic and electronic model is proposed, which supports the presence of a self-assembled ion pair between a cationic terminal Ti-hydride and an aluminate anion, with a hydrodynamic radius of ca. 16 Å., Catalytically competent titanium-hydrides are reactive and difficult to isolate. We use EPR spectroscopy to define the electronic and geometrical structures as well as dynamics of an open-shell Ti-H active in syndiospecific olefin polymerization.

The concept of a novel living encapsulated self-forming dynamic bio-membranes (ESFDM) for an innovative wastewater treatment in membrane bioreactor (MBR) is presented in the current study. The active filtering membrane is encapsulated, and thus stabilized, between two support meshes with pore in micrometer size. The combination of activated sludge, the ESFDM and the cake layer formed external to the filtering module contributed to the treatment of municipal wastewater. COD concentration reductions (average value of 95.55 ± 1.44%) by ESFDM bioreactor (ESFDMBR) were comparable to those obtained with a previously reported membrane bioreactor (MBR), where a conventional membrane was studied under the same operating conditions. The ESFDMBR, compared to the conventional MBR, obtained higher reductions of NH3-N, NO3–N and PO43–P concentrations. Increased removals of nitrogen-containing nutrients were ascribed to anoxic conditions reached in the ESFDM layer protected from the aeration by the external cake layer. Rate of increase of transmembrane pressure (TMP) per day in the ESFDMBR (0.03 kPa/day) was lower than the value obtained in the previously reported conventional MBR (8.08 kPa/day). Lower concentrations of fouling precursors in combination with the effective filtration capacity of the porous living ESFDM resulted in the reduction of the fouling rate. Analysis of microbiological community revealed that the microbial community structures in the mixed liquor and ESFDM were different. The ESFDM layer promoted growth of bacteria as indicated by the higher total cell count and higher microbial diversity compared to those observed in the mixed liquor.

The release of air pollutants from the operation of wastewater treatment plants (WWTPs) is often a cause of odor annoyance for the people living in the surrounding area. Odors have been indeed recently classified as atmospheric pollutants and are the main cause of complaints to local authorities. In this context, the implementation of effective treatment solutions is of key importance for urban water cycle management. This work presents a critical review of the state of the art of odor treatment technologies (OTTs) applied in full-scale WWTPs to address this issue. An overview of these technologies is given by discussing their strengths and weaknesses. A sensitivity analysis is presented, by considering land requirements, operational parameters and efficiencies, based on data of full-scale applications. The investment and operating costs have been reviewed with reference to the different OTTs. Biofilters and biotrickling filters represent the two most applied technologies for odor abatement at full-scale plants, due to lower costs and high removal efficiencies. An analysis of the odors emitted by the different wastewater treatment units is reported, with the aim of identifying the principal odor sources. Innovative and sustainable technologies are also presented and discussed, evaluating their potential for full-scale applicability.

[EN] The synthesis of aromatic ketimines via hydroamination of phenylacetylenes (PAs) with anilines (ANs) has been accomplished in high yields and with excellent regio- and stereo-selectivity using gold nanoparticles (AuNPs) embedded in crystalline syndiotactic polystyrene-cis-1,4-polybutadiene (sPSB) multiblock copolymer matrix. The performances of the AuNPs-sPSB catalyst exceed those of the other commercial gold catalysts as a result of the physical chemical properties of the nanoporous polystyrenic support which allows excellent activity, thermal stability and recyclability of the catalyst. Electron donating (EDGs) and electron withdrawing (EWGs) substituents onto the aromatic group of ANs and PAs yield, in all examined cases, high selectivity in the formation of the thermodynamic favoured E stereoisomer of the aromatic ketimines. Kinetic investigation of the reaction mechanism in the presence of AN and of the deuterated analogue, AN-N,N-d(2), highlighted a new reaction pathway for the hydroamination reaction, which was also supported by DFT calculations. Actually, the formation of AN aggregates stabilized by hydrogen bonding interactions produces a favourable transition state for the nucleophilic attack of AN to PA, coordinated/activated onto AuNPs surface. Moreover, an additional AN molecule cooperatively assists the 1,3-hydrogen shuttling from the N atom to the C-beta of the coordinated enamine intermediate to produce the kinetically favoured Z-ketimine intermediate that in turn evolves into the thermodynamically stable E-aromatic ketimine. The first order kinetics observed for AN, along with the experimental energetic barrier (AGl = 26.6 +/- 0.7 kcal mol(-1); AHl = 13.4 +/- 1.8 kcal mol(-1); ASl = -0.04 +/- 0.04 kcal mol(-1) K-1) found in good agreement with the energy of the transition state calculated for the 1,3-hydrogen shift in the DFT modelling, strongly support that the latter is the rate determining step in the gold catalysed hydroamination of AN with PA., The authors are grateful for founding from the Ministero dell'Universita e della Ricerca-MIUR (PRIN2017 grant) , and from the Universita degli Studi di Salerno (FARB grants) .

This review paper aims to identify the main sources of carbon dioxide (CO2) emissions from wastewater treatment plants (WWTPs) and highlights the technologies developed for CO2 capture in this milieu. CO2 is emitted in all the operational units of conventional WWTPs and even after the disposal of treated effluents and sludges. CO2 emissions from wastewater can be captured or mitigated by several technologies such as the production of biochar from sludge, the application of constructed wetlands (CWs), the treatment of wastewater in microbial electrochemical processes (microbial electrosynthesis, MES; microbial electrolytic carbon capture, MECC; in microbial carbon capture, MCC), and via microalgal cultivation. Sludge-to-biochar and CW systems showed a high cost-effectiveness in the capture of CO2, while MES, MECC, MCC technologies, and microalgal cultivation offered efficient capture of CO2 with associate production of value-added by-products. At the state-of-the-art, these technologies, utilized for carbon capture and utilization from wastewater, require more research for further configuration, development and cost-effectiveness. Moreover, the integration of these technologies has a potential internal rate of return (IRR) that could equate the operation or provide additional revenue to wastewater management. In the context of circular economy, these carbon capture technologies will pave the way for new sustainable concepts of WWTPs, as an essential element for the mitigation of climate change fostering the transition to a decarbonised economy.

The effect of addition of algae to activated sludge as active biomass in membrane bioreactors (MBRs) and electro-MBRs (e-MBRs) for wastewater remediation was examined in this study. The performances of Algae-Activated Sludge Membrane Bioreactor (AAS-MBR) and electro Algae-Activated Sludge Membrane Bioreactor (e-AAS-MBR) were compared to those observed in conventional MBR and e-MBR, which were previously reported and utilized activated sludge as biomass. The effect of application of electric field was also examined by the comparison of performances of e-AAS-MBR and AAS-MBR. Similar chemical oxygen demand (COD) reduction efficiencies of AAS-MBR, e-AAS-MBR, MBR, and e-MBR (98.35 ± 0.35%, 99.12 ± 0.08%, 97.70 ± 1.10%, and 98.10 ± 1.70%, respectively) were observed. The effect of the algae-activated sludge system was significantly higher in the nutrient removals. Ammoniacal nitrogen (NH3−N) removal efficiencies of AAS-MBR and e-AAS-MBR were higher by 43.89% and 26.61% than in the conventional MBR and e-MBR, respectively. Phosphate phosphorous (PO43−-P) removals were also higher in AAS-MBR and e-AAS-MBR by 6.43% and 2.66% than those in conventional MBR and e-MBR. Membrane fouling rates in AAS-MBR and e-AAS-MBR were lower by 57.30% and 61.95% than in MBR and e-MBR, respectively. Lower concentrations of fouling substances were also observed in the reactors containing algae-activated sludge biomass. Results revealed that addition of algae improved nutrient removal and membrane fouling mitigation. The study also highlighted that the application of electric field in the e-AAS-MBR enhanced organic contaminants and nutrients removal, and fouling rate reduction.

The first case of Coronavirus Disease 2019 (COVID-19), which is caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), in Europe was officially confirmed in February 2020. On 11 March 2020, after thousands of deaths from this disease had been reported worldwide, the WHO changed their classification of COVID-19 from a public health emergency of international concern to a pandemic. The SARS-CoV-2 virus has been shown to be much more resistant to environmental degradation than other coated viruses. Several studies have shown that environmental conditions can influence its viability and infectivity. This review summarizes current knowledge on the transmission pathways of the novel coronavirus, and directs attention towards potentially underestimated factors that affect its propagation, notably indoor spread and outdoor risk sources. The contributions of significant indoor factors such as ventilation systems to the spread of this virus need to be carefully ascertained. Outdoor risk sources such as aerosolized particles emitted during wastewater treatment and particulate matter (PM), both of which may act as virus carriers, should be examined as well. This study shows the influence of certain underestimated factors on the environmental behavior and survival of the SARS-CoV-2 virus. These aspects of coronavirus propagation need to be accounted for when devising actions to limit not only the current pandemic but also future outbreaks. Graphic abstract

The rising of greenhouse-gas emissions (GHG), during the last 200 years, is associated to the well known global warming phenomena. One of the main sources of CO2-equivalent GHGs emissions are the environmental protection plants accounting for 1.57% of the global emissions and thus sustainable and effective technologies for their mitigation are strongly needed. The current paper presents and discusses the assessment of an innovative membrane photo-bioreactor (MPBR) whose aim was the promotion of CO2 capture from conveyed flows, such as those from wastewater treatment plants (WWTPs), landfill and composting plants, for production and energy valorisation of algal biomass. Chlorella vulgaris microalgae strain was selected as photosynthetic platform for the abovementioned purposes. The influence of various operating parameters has been explored, including the photosynthetic photon flux densities (PPFD) (60 and 120 μmol m−2 s−1), liquid/gas ratio (L/G = 5, 10 or 15) and CO2 concentration (5, 10 and 15%) in order to investigated their effects on carbon capture effectiveness and biomass production. The results demonstrated that the increasing of PPFD significantly enhanced the biomass production in terms of biomass productivity (P) and total dry weight (DW). The highest biomass concentration of 1.01 g L−1 was achieved at PPFD of 120 μmol m−2 s−1 with a L/G of 15. Under the aforementioned conditions, carbon dioxide removal efficiency (RE) reached values up to 80%. In addition, the novel MPBR equipped with an innovative self-forming dynamic membrane (SFDM) showed a simultaneous biomass harvesting rate of 41 g m−2 h−1.

In recent years, the use of renewable raw materials for the production of chemicals has been the subject of different studies. In particular, the interest of the present study was the use of oleins, mixtures of free fatty acids (FFAs), and oleic acid to produce bio-based components for lubricants formulations and the investigation of the performance of a styrene-divinylbenzene acid resin (sPSB-SA) in the esterification reaction of fatty acids. This resin has shown good activity as a heterogeneous catalyst and high stability at elevated temperatures (180 °C). It was tested in the esterification reaction of oleic acid with 1,3-propanediol and of oleic acid with glycerol. In particular, the esterification reactions were performed in a steel stirred batch reactor and a PBR loop reactor. Tests were conducted varying the reaction conditions, such as alcohol type, temperature, reaction time, and catalysts, both homogeneous and heterogeneous ones. From the obtained results, acid resin (both in reticulated and not-reticulated form) showed high activity in esterification reaction of oleic acid with 1,3-propanediol and of oleic acid with glycerol and good resistance to the deactivation, thus, they can be considered promising candidates for future applications in continuous devices. Viscosity tests were performed, underlining the good properties of the obtained products as lubricant bases.

The rising of greenhouse-gas emissions (GHG), during the last 200 years, is associated to the well known global warming phenomena. One of the main sources of CO

Tannery wastewater contains large amounts of pollutants that, if directly discharged into ecosystems, can generate an environmental hazard. The present investigation has focused the attention to the remediation of wastewater originated from tanned leather in Tunisia. The analysis revealed wastewater with a high level of chemical oxygen demand (COD) of 7376 mgO2/L. The performance in reduction of COD, via electrocoagulation (EC) or UV photolysis or, finally, operating electrocoagulation and photolysis in sequence was examined. The effect of voltage and reaction time on COD reduction, as well as the phytotoxicity were determined. Treated effluents were analysed by UV spectroscopy, extracting the organic components with solvents differing in polarity. A sequential EC and UV treatment of the tannery wastewater has been proven effective in the reduction of COD. These treatments combined afforded 94.1 % of COD reduction, whereas the single EC and UV treatments afforded respectively 85.7 and 55.9 %. The final COD value of 428.7 mg/L was found largely below the limit of 1000 mg/L for admission of wastewater in public sewerage network. Germination tests of Hordeum Vulgare seeds indicated reduced toxicity for the remediated water. Energy consumptions of 33.33 kW h/m3 and 314.28 kW h/m3 were determined for the EC process and for the same followed by UV treatment. Both those technologies are yet available and ready for scale-up.

This paper presents an updated and comprehensive review on the different methods used for detection and quantification of viruses in wastewater treatment systems. The analysis of viability of viruses in wastewater and sludge is another thrust of this review. Recent studies have mostly focused on determining the abundance and diversity of viruses in wastewater influents, in samples from primary, secondary, and tertiary treatment stages, and in final effluents. A few studies have also examined the occurrence and diversity of viruses in raw and digested sludge samples. Recent efforts to improve efficiency of virus detection and quantification methods in the complex wastewater and sludge matrices are highlighted in this review. A summary and a detailed comparison of the pre-treatment methods that have been utilized for wastewater and sludge samples are also presented. The role of metagenomics or sequencing analysis in monitoring wastewater systems to predict disease outbreaks, to conduct public health surveillance, to assess the efficiency of existing treatment systems in virus removal, and to re-evaluate current regulations regarding pathogenic viruses in wastewater is discussed in this paper. Challenges and future perspectives in the detection of viruses, including emerging and newly emerged viruses such as the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), in wastewater systems are discussed in this review., Graphical abstract Unlabelled Image, Highlights • An overview on virus occurrence, detection and viability in wastewater and sludge • Molecular methods are extensively used to detect viruses in wastewater. • Use of sequencing to monitor virus abundance and diversity in wastewater and sludge • Detection and quantification of viruses in wastewater to monitor disease outbreaks • Research need: studies on detection methods of emerging viruses such as SARS-CoV-2

The stereoselective polymerization of β-myrcene and β-ocimene and their binary copolymerization with styrene promoted by titanium complexes dichloro{1,4-dithiabutanediyl-2,2′-bis(4,6-di-tert-butyl-phenyl)}titanium (1), dichloro{1,4-dithiabutanediyl-2,2′-bis[4,6-bis(2-phenyl-2-propyl)phenoxy]}titanium (2) and Ti(η5-C5H5)-(η2-MBMP)Cl (3) (MBMP = 2,2'methylenebis(6-tert-butyl-4-methylphenoxo)) activated by methylaluminoxane (MAO) is reported. Complex 1 produces a prevalently trans-1,4-polymyrcene (92%), the more sterically encumbered pre-catalyst 2 gives a major amount of 3,4-units (40%). Conversely the pre-catalyst 3 produces cis-1,4-polymyrcene with good selectivity (92%). The catalyst 1 promotes the copolymerization of β-myrcene with styrene giving the corresponding copolymers in a wide range of composition (χs = 0.14–0.90). In the case of β-ocimene the catalysts 1 and 2 produce a polymer with 1,4-trans structure (70%) at 70 °C while at lower temperature (0 °C) an isotactic poly-1,2-ocimene (>99%) is obtained. The catalyst 3 produces a less stereoregular polymer with prevalently cis-1,4-microstructure (55%). The catalyst 2 also promotes the copolymerization of β-ocimene with styrene in a wide range of composition (χs = 0.23–0.87).

Theranostics based on two-photon excitation of therapeutics in the NIR region is an emerging and powerful tool in cancer therapy since this radiation deeply penetrates healthy biological tissues and produces selective cell death. Aggregates of gold nanoparticles coated with glutathione corona functionalized with the dansyl chromophore (a-DG-AuNPs) were synthesized and found efficient nanodevice for applications in photothermal therapy (PTT). Actually the nanoparticle aggregation enhances the quenching of radiative excitation and the consequent conversion into heat. The a-DG-AuNPs are readily internalized in Hep G2 where the chromophore acts as both antenna and transducer of the NIR radiation under two-photons excitation, determining efficient cell ablation via photothermal effect.

The direct synthesis of syndiotactic polystyrene-block-polyethylene copolymer (sPS-b-PE) with a diblock structure has been achieved. The synthetic strategy consists of the sequential stereocontrolled polymerization of styrene and ethylene in the presence of a single catalytic system: cyclopentadienyltitanium(IV) trichloride activated by modified methylaluminoxane (CpTiCl3/MMAO). The reaction conditions suitable for affording the partially living polymerization of these monomers were identified, and the resulting copolymer, purified from contaminant homopolymers, was fully characterized. Gel permeation chromatography coupled with two-dimensional NMR spectroscopy COSY, HSQC, and DOSY confirmed the block nature of the obtained polymer, whose thermal behaviour and thin film morphology were also investigated by differential scanning calorimetry, powder wide angle x-ray diffraction, and atomic force microscopy.

Considerable attention has been recently given to possible transmission of SARS-CoV-2 via water media. This review addresses this issue and examines the fate of coronaviruses (CoVs) in water systems, with particular attention to the recently available information on the novel SARS-CoV-2. The methods for the determination of viable virus particles and quantification of CoVs and, in particular, of SARS-CoV-2 in water and wastewater are discussed with particular regard to the methods of concentration and to the emerging methods of detection. The analysis of the environmental stability of CoVs, with particular regard of SARS-CoV-2, and the efficacy of the disinfection methods are extensively reviewed as well. This information provides a broad view of the state-of-the-art for researchers involved in the investigation of CoVs in aquatic systems, and poses the basis for further analyses and discussions on the risk associated to the presence of SARS-CoV-2 in water media. The examined data indicates that detection of the virus in wastewater and natural water bodies provides a potentially powerful tool for quantitative microbiological risk assessment (QMRA) and for wastewater-based epidemiology (WBE) for the evaluation of the level of circulation of the virus in a population. Assays of the viable virions in water media provide information on the integrity, capability of replication (in suitable host species) and on the potential infectivity. Challenges and critical issues relevant to the detection of coronaviruses in different water matrixes with both direct and surrogate methods as well as in the implementation of epidemiological tools are presented and critically discussed., Graphical Abstract ga1

Copolymers of styrene with 2-vinylfuran (S-co-2VF) were reacted with maleimides to yield functionalized copolymers via Diels-Alder (DA) reaction. The polymer compositions and the chemical structure of the DA cycloadducts were fully characterized by means of NMR spectroscopy. The kinetic and thermodynamic parameters were thus assessed for the DA and backward reaction (r-DA) to gain information on this click reaction using a set of equations properly designed. The VT NMR monitoring of the reactions allowed to calculate the apparent rate constants for the formation and decoupling of the DA cycloadducts with both the endo and exo configurations in the range of temperature 70–120 °C. The activation energy barriers of 47.8 ± 5.6 kJ mol−1 and 174 ± 17 kJ mol−1 were calculated from the Arrhenius plots for the DA and r-DA reactions, respectively. The Eyring-Polanyi equation permitted also to assess the enthalpic and entropic contributions of 171 ± 17 kJ mol−1 and 0.09 ± 0.15 kJ K−1 mol−1 for the r-DA reaction. The thermodynamic equilibrium constants yielded the enthalpy (-157 ± 14 kJ mol−1) and entropy (-370 ± 40 J K−1 mol−1) of formation of the DA cycloadducts.

Glycidol is converted into glycerol carbonate (GC) by coupling with CO2 in the presence of tetrabutylammonium bromide (TBAB) under mild reaction conditions (T=60 °C, PCO2 =1 MPa) in excellent yields (99 %) and short reaction time (t=3 h). The unusual reactivity of this substrate compared to other epoxides, such as propylene oxide, under the same reaction conditions is clearly related to the presence of a hydroxyl functionality on the oxirane ring. Density functional theory calculations (DFT) supported by 1 H NMR experiments reveal that the unique behavior of this substrate is a result of the formation of intermolecular hydrogen bonds into a dimeric structure, activating this molecule to nucleophilic attack, and allowing the formation of GC. Furthermore, the glycidol/TBAB catalytic system acts as an efficient organocatalyst for the cycloaddition of CO2 to various oxiranes.

Group 4 complexes 1–3 [1 = (t-BuOS)2Ti(O-i-Pr)2; 2 = (t-BuOS)2Zr(O-t-Bu)2; 3 = (t-BuOS)2Hf(O-t-Bu)2] supported by two phenolate bidentate ligands (t-BuOS-H = 4,6-di-tert-butyl-2-phenylsulfanylphenol) promote the well-controlled ring opening polymerization of rac-β-butyrolactone. In presence of isopropanol, low dispersities and molecular weights proportional to the equivalents of isopropanol are achieved. Moreover, the zirconium complex is effective in the copolymerization of rac-β-butyrolactone with rac-lactide. The [13]C nuclear magnetic resonance analysis revealed that the obtained copolymers have a tapered diblock microstructure consisting of an initial block composed of lactide sequences and a terminal block composed of butyrolactone sequences. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 3132–3139

Metal-free Friedel-Crafts benzylation (FCB) of scarcely reactive arenes and heteroarenes was performed under on-water conditions by an environmentally sustainable procedure. The catalytic strategy exploits the hydrophobicity of the resorcinarene macrocycle 1 a. The proposed mechanism is based on the activation of benzyl chloride by H-bonding interactions with catalyst 1 a. In fact, under on-water conditions the hydrophobic amplification of the strength of the H-bonding interactions between the OH groups of the resorcinarene catalyst and the chlorine atom of benzyl chloride leads to polarization of the C-Cl bond, which consequently promotes electrophilic attack of the π nucleophile. Thus, many arenes and heteroarenes were efficiently benzylated under mild on-water conditions by using resorcinarene 1 a as catalyst. The FCB of benzene is industrially relevant for the synthesis of diphenylmethane, and hence the on-water procedure was extended to the gram-scale synthesis of diphenylmethane, starting from benzene and benzyl chloride in the presence of resorcinarene catalyst 1 a.