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This review describes the advances of heterogenous phase‐transfer catalysts onium‐based and their importance from a sustainable point of view. Although heterogeneous phase‐transfer catalysts have shown incredible advantages in many organic reactions, examples of supported phase‐transfer catalysts onium‐based are still limited. In this review, we will examine the most common supports, including polymers, clays, and inorganic materials. Additionally, new recent developments in carbon materials application as efficient heterogeneous phase‐transfer catalysts in water will be reported, opening a new route toward green and sustainable procedures. Furthermore, considering the ever‐growing interest in asymmetric synthesis we wish to discuss the important achievements in the field of chiral heterogeneous phase‐transfer catalysts. [ABSTRACT FROM AUTHOR]

An effective non-covalent compatibilization method for graphite and low-density polyethylene is reported. To obtain this result, pyren-1-yl-stearate (P1S) was synthesized, characterized and mixed with graphite to provide a better dispersion in polyethylene matrix. The P1S improves the dispersion of carbon filler in polyethylene through non-covalent compatibilization: the pyrenyl group gives π−π stacking interactions with graphite and the stearyl chain provides van der Waals interaction with the polymer chain (specifically London dispersion forces). In this study, different P1S/graphite fillers were prepared with a ratio by weight of 90/10 and 50/50, respectively, by using manual and ball-milling mixing. Their stability, interaction and morphology were evaluated through TGA, RX, and SEM. Thermogravimetric analyses showed that ball-milling mixing is more effective than manual mixing in promoting π−π stacking interactions of molecules such as P1S ester containing an alkyl chain and aromatic rings. The role of ball milling is confirmed by X-ray diffraction measurements since it was possible to observe both exfoliation and intercalation phenomena when this technique was used to mix the P1S ester with graphite. SEM analyses of polyethylene containing 1% of the carbon fillers again highlighted the importance of ball milling to promote the interaction of the ester with graphite and, simultaneously, the importance of the alkyl chain in order to achieve polyethylene-graphite compatibilization. [ABSTRACT FROM AUTHOR]

This review reports on the catalytic activity of graphene oxide (GO) and high‐surface‐area graphite (HSAG) for some relevant organic reactions. It is shown that the main drawbacks of graphite‐based catalysts, that is, high catalyst loading and generally poor selectivity, can often be removed by operating under solvent‐free conditions. Moreover, some reactions that are catalyzed by GO as well as HSAG are presented. For these reactions, π stacking of the aromatic substrates with the graphitic planes plays a predominant role in the catalytic activity and the unexpected diastereoselective and enantioselective behaviors. [ABSTRACT FROM AUTHOR]

Small amounts of carbon nanofillers, specifically high-surface-area graphite (HSAG) and more effectively carbon black (CB), are able to solve the well-known problem of degradation (molecular weight reduction) during melt processing, for the most relevant biodegradable polymer, namely poly(lactic acid), PLA. This behavior is shown by rheological measurements (melt viscosity during extrusion experiments and time sweep-complex viscosity) combined with gel permeation chromatography (GPC) experiments. PLA's molecular weight, which is heavily reduced during melt extrusion of the neat polymer, can remain essentially unaltered by simple compounding with only 0.1 wt % of CB. At temperatures close to polymer melting by compounding with graphitic fillers, the observed stabilization of PLA melt could be rationalized by scavenging traces of water, which reduces hydrolysis of polyester bonds. Thermogravimetric analyses (TGA) indicate that the same carbon fillers, on the contrary, slightly destabilize PLA toward decomposition reactions, leading to the loss of volatile byproducts, which occur at temperatures higher than 300 °C, i.e., far from melt processing conditions. [ABSTRACT FROM AUTHOR]

In this work, some films of poly(ε-caprolactone) (PCL) containing lysozyme at 5% by weight are obtained. Lysozyme is a natural antimicrobial molecule. The films are submitted to cold drawing process at three different draw ratios, λ = 3, 4, and 5, where λ is the ratio between final and initial length. Morphology, physical and barrier properties of the drawn samples are studied and correlated to the release of lysozyme. Tests against Bacillus sp are performed and correlated to the material texture. The molecular orientation of uniaxially drawn lysozyme doped PCL films is demonstrated to be a significant parameter for controlled release monitoring of the active molecule and the antimicrobial activity. [ABSTRACT FROM AUTHOR]

31405139 4 Luca G., Tadiello L., Acocella M.R., Maggio M., Guerra G., Vittore A. Tyre and Elastomeric Compound for Tyre, Comprising Cross-Linked Phenolic Resins. The research interest of this Special Issue "Catalytic Applications for Oxidized Carbon Materials" includes, but is not limited, to the synthesis, characterization and catalytic application of different carbon materials (charcoal, carbon black, nanotubes, graphite), with particular attention to sustainability and reducing the environmental impact from the synthesis of the catalyst to its application. This Special Issue from I Materials i , entitled "Catalytic Applications for Oxidized Carbon Materials", aims to publish original papers on new scientific and applied research, providing great contributions to the understanding of oxidized carbon materials and related synthesis, characterization and applications. [Extracted from the article]

Poly(lactic acid) (PLA) is one of the most widely used thermoplastic materials for 3D printing, particularly in the Fused Filament Fabrication technique. However, the printing process generates waste products and even though PLA is compostable, the possibility of recycling it provides ecological and economical benefits. In this work, a study on the stabilization of recycled PLA using charcoal (CC) was carried out, with the aim of overcoming the well-known problem of degradation (reduction in molecular weight) of PLA, during remelting. Microscopic investigations showed good dispersion of the filler in the polymer matrix, as well as better adhesion between the printed layers. Thermal analyses (Differential scanning calorimetry and thermogravimetry) indicate a stabilization of PLA waste because of the addition of small concentrations of CC to the recycled polymer matrix. These data are confirmed by GPC analyses, which show that the addition of filler is associated with higher molecular weight. Mechanical analysis indicated improved elongation at break and elasticity. Finally, a key ring was printed as an example of the better printability of the filament containing CC. The results indicate that a stabilization of the recycled PLA with a very low concentration of CC has been achieved. Improved 3D printability and properties of the 3D printed objects can be attained through recycling and recovery of wasted PLA, according to sustainability and circular economy matters. [ABSTRACT FROM AUTHOR]

Abstract: Oxidized carbon black efficiently catalyzed addition of amines to 1,3‐dicarbonyl compounds under solvent‐free conditions at room temperature. This methodology is eco‐friendly and cheap, with a very easy work up and the possibility to recover and recycle the catalyst. Finally, the elaborated methodology can be conveniently exploited for the synthesis of 1,5‐benzodiazepine. [ABSTRACT FROM AUTHOR]

This article compares the catalytic activities of oxidized carbon black (oCB) and graphene oxide (eGO) samples on the kinetics of a reaction of diglycidyl ether of bisphenol A (DGEBA) with a diamine, leading to crosslinked insoluble networks. The study is mainly conducted by rheometry and Differential Scanning Calorimetry (DSC). Following the same oxidation procedure, CB samples are more efficiently oxidized than graphite samples. For instance, CB and graphite samples with high specific surface areas (151 and 308 m²/g), as oxidized by the Hummers' method, exhibit O/C wt/wt ratios of 0.91 and 0.62, respectively. Due to the higher oxidation levels, these oCB samples exhibit a higher catalytic activity toward the curing of epoxy resins than fully exfoliated graphene oxide. [ABSTRACT FROM AUTHOR]

The addition of acetone to rac -2-methylsulfinyl-benzaldehyde, catalyzed by secondary amines (morpholine, piperidine, l -proline, l -prolinamide and ( S )-(–)-α,α-diphenyl-2-pyrrolidinemethanol trimethylsilyl ether), was realized. Interesting aspects, such as 1,4-asymmetric induction by the remote sulfinyl group of the aldehyde but also the stereochemical control and kinetic resolution of the racemic substrate by the chiral organocatalyst were examined. Finally, an unexpected stereoselective retro-aldol reaction catalyzed by l -proline was pointed out. [ABSTRACT FROM AUTHOR]

The ring-opening reactions of epoxides with amines were efficiently and regioselectively catalyzed by high-surface-area graphite and graphene oxide under metal-free and solvent-free conditions. For epoxides without aryl groups, catalytic activity was observed only for graphene oxide, and hence, the activity must have been due to its acidic groups. For styrene oxide, instead, graphite and graphene oxide exhibited rather similar catalytic activities, and hence, the activity was mainly due to activation of the electrophilic epoxide by π-stacking interactions with the graphitic π system. The described aminolysis procedure is green and cheap because the catalyst can be recovered and recycled without loss of efficiency. Moreover, these heterogeneous catalysts exert high stereoselective control in the presence of nonracemic epoxides and provide chiral β-amino alcohols with enantiomeric excess values up to 99 %. [ABSTRACT FROM AUTHOR]

Films exhibiting nanoporous‐crystalline (NC) phases of poly(2,6‐dimethyl‐1,4‐phenylene) oxide (PPO), which are highly effective to absorb apolar organic guest molecules, are also able to absorb polar molecules (like alcohols and carboxylic acids) but only from concentrated organic solutions. NC PPO films, which do not absorb alcohols and carboxylic acids from diluted aqueous solutions, exhibits a huge uptake (even above 30 wt %) of benzyl alcohol (BAL) and benzoic acid (BA), if BA is obtained by spontaneous room temperature oxidation of BAL in aqueous solution. This phenomenon is rationalized by an easy uptake, mainly by the PPO intrahelical crystalline empty channels, of a BAL/BA 1/1 hydrogen‐bonded dimer. This huge uptake of BAL/BA dimer by NC PPO films, which is also fast for films exhibiting the orientation of the crystalline helices perpendicular to the film plane (c⊥ orientation), can be exploited for purification of water from BAL, when present in traces. High and fast sorption of a hydrogen bonded dimer and negligible sorption of the two separate compounds is possibly unprecedented for absorbent materials. [ABSTRACT FROM AUTHOR]

Biodegradable polymers are raising an increasing interest as alternative to oil-based materials. Among available biodegradable polymers, the most promising is possibly poly(l -lactic acid) (PLLA), which can be produced from renewable resources at reasonable costs. However, PLLA has some processing limitations, mainly associated with slow melt crystallization kinetics. In this work, an attempt is made to overcome these PLLA limitations, by using different kinds of carbon-based nanofillers. PLLA compounds were prepared in a twin screw extruder and characterized mainly by gel permeation chromatography, rotational rheometry and differential scanning calorimetry. Alkylated carbon black (aCB) in PLLA compounds not only induces high melt thermal stabilization (as also occurs with other carbon based nanofillers) but also acts as a nucleating agent, thus reducing crystallization times. aCB nucleation of PLLA is possibly due to the well known tendency of hydrocarbon tails to form ordered local aggregates, when bounded to solid structural layers. [Display omitted] • Alkylated carbon black (aCB) in PLLA compounds not only induces thermal stabilization but also acts as a nucleating agent. • PLLA compounds with 1.0 wt% of aCB present crystallization times reduced of at least ten times. • Nucleation for PLLA crystallization is associated with the presence of long alkyl chains being bounded to graphitic layers. • Ordered aggregates of hydrocarbon tails are expected to be crystallization nuclei of the linear aliphatic polyester. [ABSTRACT FROM AUTHOR]

Abstract Graphite oxide efficiently promotes the stereoselective Mukaiyama aldol reaction of 2-(trimethylsilyloxy) furan in solvent free conditions assuring a good level of diastereoselectivity. The catalyst can be easily recovered and reused making the procedure cheap and sustainable. The GO ability to control the stereochemical pathway opens new scenes for the possible application in other synthetic transformations. [ABSTRACT FROM AUTHOR]

For the δ form of syndiotactic polystyrene, a nanoporous triclinic modification, different from the well-established and widely used nanoporous monoclinic modification, is presented. Detailed routes to triclinic or monoclinic modifications, which involve different guest removal procedures from different δ-clathrates, are described and rationalized. Surprisingly, both triclinic and monoclinic δ modifications can be obtained by both triclinic and monoclinic δ-clathrates. The triclinic modification, with respect to the monoclinic one, presents the advantage of higher uptake of pollutants having molecular volume in the range 0.13–0.22 nm 3 , mainly when present only as traces in water or in air. In particular, the different molecular selectivity of triclinic and monoclinic δ modifications, favoring n -decane and n -hexane sorption, respectively, is described. This behavior is attributed to the crystalline cavities of the triclinic δ modification, which are halved in number and increased in volume with respect to those of monoclinic δ modification. [ABSTRACT FROM AUTHOR]

The strong influence of graphite oxide (GO) nanofiller on the glass transition temperature ( T g ) of epoxy resins, generally attributed to restricted molecular mobility of the epoxy matrix by the nanofiller or to the crosslinking of GO layers via the epoxy chains, is investigated. The study confirms that large increases of the glass transition temperature of the nanocomposite can be observed in presence of GO. However, similar T g increases are observed, when the filler is a high-surface-area graphite (HSAG), lacking oxidized groups. Moreover, these T g differences tend to disappear as a consequence of aging or thermal annealing. These results suggest that the observed T g increases are mainly due to a catalytic activity of graphitic layers on the crosslinking reaction between the epoxy resin components (epoxide oligomer and di-amine), rather than to reaction of the epoxide groups with functional groups of GO. This hypothesis is supported by investigating the catalytic activity of graphite-based materials on reactions between analogous monofunctional epoxide and amine compounds. [ABSTRACT FROM AUTHOR]

Abstract: A new methodology for the oxidation of aldehydes promoted by commercially available Fe3O4 nanoparticles (Fe3O4 NPs) activated by ethyl acetoacetate was developed. The use of ethyl acetoacetate as additive was crucial to achieve high reactivities. All reactions were realized under solvent free conditions, using air or tBuOOH as oxidants. Finally, the separation and reuse of the magnetically recoverable nanoparticles make this methodology very practical, simple and economical. [Copyright &y& Elsevier]

Abstract: Chiral 2-methylsulfinyl benzaldehyde proved to be a valuable starting material for a convenient approach towards a variety of imino- and amino-sulfoxides. The catalytic properties of these new ligands, as potential activators of allyl trichlorosilane, have been exploited in new catalytic procedures for the synthesis of enantioenriched homoallylic alcohols. [ABSTRACT FROM AUTHOR]

Abstract: Chan''s diene proved to react with aromatic aldehydes under organocatalytic conditions in presence of a chiral naphthyl-TADDOL derivative to give vinylogous aldols (up to 65% ee) with complete γ-selectivity. A further process of hetero-Diels–Alder cycloaddition, leading to chiral pyran-4-one derivatives (up to 60% ee), was favoured by electron-withdrawing substituents on the aromatic ring. [Copyright &y& Elsevier]

Abstract: SiCl4 is an efficient and selective catalyst for the vinylogous Mannich reaction of linear and cyclic synthetic equivalents of acetoacetate dianion, leading to δ-amino-β-ketoesters in moderate to high yields and complete γ-selectivity; anti-diastereoselectivity was observed by using a γ-methyl-substituted cyclic silyloxydiene. [Copyright &y& Elsevier]

Abstract: Here reported is an unusual catalytic ability of Eu(OTf)3 in the oxidative conversion of 5-alkylidene-4,5-dihydrofuran derivatives in the corresponding furylhydroperoxides with tert-butyl hydroperoxide. Furthermore, an enantioselective process of disproportionation of furylhydroperoxides has been highlighted in the presence of the Jacobsen’s catalyst (S,S)-(+)-N,N′-Bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediaminomanganese(III) chloride. [Copyright &y& Elsevier]

Abstract: Hydrogen-bonding activation of aromatic aldehydes by a TADDOL-derivative promotes the vinylogous aldol reaction of Chan’s diene in moderate efficiency and enantioselectivity. Electron-poor aromatic aldehydes show an enhanced reactivity and a competing asymmetric hetero-Diels–Alder reaction takes place in comparable (or higher) yields and enantiomeric excesses. [Copyright &y& Elsevier]

Abstract: The vinylogous aldol reaction of O-silyl dienolates deriving from 2,2-dimethyl-[1,3]-dioxin-4-ones proceeds in moderate to excellent yields in the presence of catalytic amounts of PhCOOH under solvent-free conditions. Modest to good yields can be obtained by using silica gel or 3Å molecular sieves as heterogeneous catalysts. [Copyright &y& Elsevier]

A strong enhancement of the enantiomeric excess can be obtained by performing the enantioselective aldol reaction of Chan''s diene in the presence of enantiomerically enriched Ti(O-i-Pr)4/BINOL catalysts derived from mixing pre-prepared solutions of enantiopure Ti(O-i-Pr)4/(R)-BINOL and Ti(O-i-Pr)4/(S)-BINOL at different concentrations. [Copyright &y& Elsevier]

In the presence of catalytic amount of chiral Ti(OiPr)4/BINOL (0.08 equiv.) the asymmetric aldol condensation of 6-methyl-4H-[1,3]-dioxin-4-one-derived silyloxydienes takes place in high yields and enantiomeric excesses with aromatic, heteroaromatic, unsaturated and aliphatic aldehydes. Notable amplification of enantiomeric excesses have been obtained by using enantioenriched catalytic systems. [Copyright &y& Elsevier]

Initial concentration of enantioenriched or enantiopure catalysts proved to be an important factor for the achievement of a more pronounced amplification of ee''s in the Ti(IV)/BINOL-catalyzed aldol reaction of an O-silyldienolate. [Copyright &y& Elsevier]

Abstract: Chiral homoallylic alcohols are easily accessible by asymmetric allylation of aldehydes with allyl trichlorosilane in the presence of catalytic amounts of a chiral tetradentate bis-sulfoxide, as organocatalyst, whose synthesis is reported. [Copyright &y& Elsevier]

Abstract: Chiral δ-hydroxy-β-ketoesters are easily available through the enantioselective vinylogous aldol reaction of Chan’s diene promoted by a SiCl4/chiral phosphoramide catalytic system. The procedure is conveniently exploited for a very rapid approach to (+)-kavain, a natural bio-active α-pyrone compound. [Copyright &y& Elsevier]

The organocatalytic α-hydroxylation of β-keto esters using cinchona-alkaloid derivatives as the catalyst and peroxides as the terminal oxidant has been investigated and is shown to proceed in high yields and with good enantioselectivity. The scope of the reaction is demonstrated for various substrates, and furthermore, the preparation of optically active anti-diols is presented. [ABSTRACT FROM AUTHOR]

E- and Z-Enediones are easily accessible by controlled oxidation of 2,5-disubstituted furans with Mo(CO)6/cumyl hydroperoxide system. The use of t-butyl hydroperoxide, as oxygen donor, leads to the formation of 2H-pyran-3(6H)-one derivatives. [Copyright &y& Elsevier]

The development of pressure ulcers, associated with increased temperature and moisture in specific areas of the body, and the risk of microbial infections in patients lying in a static position for prolonged periods of time represents a serious issue in medicine. In order to prevent the formation of pressure ulcers, this work aims to present advanced nanostructured coatings developed by three research groups. Nanometric silver, ash and functionalized torrefied biomass were the basis for the treatment of wound dressings to improve thermal conductivity and antimicrobial properties of the conventional cotton gauzes. Each treatment was performed according to its own optimized method. The treated fabrics were characterized in terms of antimicrobial properties, heat transfer, morphology and hydrophobic behavior. The results demonstrated the effectiveness of the deposition treatments also in synergistic actions. In particular, the antibacterial efficacy was improved in all the samples by the addition of silver treatment, and the thermal conductivity was enhanced by around 58% with nanometric ashes. A further step of the study involved the designing of two multilayer systems evaluated using circuit models for determining the total thermal conductivity. In this way, both systems were designed with the aim to guarantee simultaneous efficacy: high antibacterial and hydrophilic properties at the skin level and more hydrophobic and conductive behaviors toward the external environment. [ABSTRACT FROM AUTHOR]

Influence of different graphite-based nanofillers on crosslinking reaction of resorcinol, as induced by hexa(methoxymethyl)melamine, is studied. Curing reactions leading from low molecular mass compounds to crosslinked insoluble networks are studied by indirect methods based on Differential Scanning Calorimetry. Reported results show a catalytic activity of graphene oxide (eGO) on this reaction, comparable to that one already described in the literature for curing of benzoxazine. For instance, for an eGO content of 2 wt %, the exothermic crosslinking DSC peak (upon heating at 10 °C/min) shifted 6 °C. More relevantly, oxidized carbon black (oCB) is much more effective as catalyst of the considered curing reaction. In fact, for an oCB content of 2 wt %, the crosslinking DSC peak can be shifted more than 30 °C and a nearly complete crosslinking is already achieved by thermal treatment at 120 °C. The possible origin of the higher catalytic activity of oCB with respect to eGO is discussed. [ABSTRACT FROM AUTHOR]

The goal of this research is to improve preparation of charcoal adducts in a manner suitable for cationic drug release, possibly using an eco-friendly procedure. Charcoal, widely commercialized for human ingestion, is oxidized by hydrogen peroxide in mild conditions. Adducts of a cationic drug (lidocaine hydrochloride, a medication used as local anesthetic) with charcoal are prepared after basification of charcoal and characterized mainly by elemental analysis, wide-angle X-ray diffraction, infrared spectroscopy and thermogravimetry. The drug in the prepared adducts is present in amount close to 30% by weight and can be readily released to both neutral and acidic aqueous solutions. Cation release, as studied by UV spectra of aqueous solutions, is faster in acidic solutions and is faster than for adducts with graphite oxide, which can be prepared only in harsh conditions. [ABSTRACT FROM AUTHOR]

The article presents chemical equations for the article "BInfluence of a Remote Sulfinyl Group on L-Proline-Catalyzed Direct Asymmetric Aldol Addition of Acetone" by R. Villano and colleagues published in "Tetrahedron" in 2016.

The article presents chemical equations for the article "Green Regio- and Enantioselective Aminolysis Catalyzed by Graphite and Graphene Oxide under Solvent-Free Conditions" by M. R. Acocella and others published in "ChemCatChem" in 2016.

An abstract of the article "Regio- and Enantioselective Friedel-Crafts Reactions of Indoles to Epoxides Catalyzed by Graphene Oxide: A Green Approach" by M. R. Acocella and colleagues is presented.

The article presents chemical equations for the article "Fe3O4 Nanoparticles/Ethyl Acetoacetate System for the Efficient Catalytic Oxidation of Aldehydes to Carboxylic Acids" by R. Villano and others, published in the periodical "Tetrahedron Letters" in 2014.

Ball milling technology was employed to increase the adsorption capacity of biochar with respect to methylene blue as a model pollutant. Comparative studies on the adsorption ability were conducted on ball-milled biochar and biochar chemically modified by oxidation and alkaline treatment, showing that ball milling produces higher performances since increases available active sites. The particle size reduction, with the consequence of an increase in the surface area was hypothesized to be responsible for the high removal efficiency. The adsorption kinetics follow s a pseudo-second-order model, implying that the process is affected by chemisorption. Moreover, the Langmuir model proved that the maximum monolayer adsorption capacity increased to 185.18 mg/g. Design of experiments allowed for evaluating the pH and initial concentration values, which maximized the removal efficiency. The milled biochar was also regenerated and reused over six times, resulting in a drop of only 1 %. [Display omitted] • Ball milling technology increases the adsorption capacity of biochar with respect to methylene blue as a model pollutant. • Compared to chemically modified biochars, ball-milled biochar showed higher adsorption performance. • The adsorption kinetics follow a pseudo second-order model implying that the process is affected by chemisorption. • The milled biochar was also regenerated and reused over six times resulting in a drop of only 1 %. [ABSTRACT FROM AUTHOR]

The reaction of indole with chalcones, to give Michael-type adducts, was found to occur with good efficiency (up to 98% yield) and moderate enantioselectivity (up to 52% e.e.) in the presence of a chiral BINOL-based phosphoric acid. Furthermore, the alkylation products can be obtained in much higher e.e.s after one only crystallization. [ABSTRACT FROM AUTHOR]

• TiO 2 /biochar hybrid system was easily prepared by ball milling route. • Tannery dyes removal through simultaneous adsorption and photocatalysis. • Compared with bare TiO 2 , the removal efficiency of TiO 2 /biochar was enhanced. • TiO 2 /biochar hybrid system exhibited high stability during five reuse cycles. TiO 2 /biochar (C/TiO 2) BM hybrid photocatalytic system is prepared, for the first time, by a cost-effective method (ball-milling procedure) and used for the removal of two organic dyes, labeled as Acid Blue 7 and Red RTN, employed in the tanning industry. The physicochemical properties of the (C/TiO 2) BM system are investigated by different characterization methods, evidencing the presence of TiO 2 in anatase phase in the (C/TiO 2) BM composite. The photocatalytic performance of (C/TiO 2) BM is evaluated in the degradation of Acid Blue 7 and Red RTN in the presence of UV light irradiation. The photocatalytic results of (C/TiO 2) BM show a similar degradation efficiency (about 70 %) for both dyes under UV light at the spontaneous pH of the solution (pH = 6). On the other hand, photocatalytic tests under acidic conditions (pH = 2) indicate higher adsorptive and photocatalytic properties of (C/TiO 2) BM composite with an overall removal efficiency of Acid Blue 7 and Red RTN of 86 and 95 %, respectively. Finally, (C/TiO 2) BM is reused for up to five cycles without loss of removal performances, underlining the stability of the composite. Therefore, the (C/TiO 2) BM composite could be an effective, recyclable, and stable hybrid photocatalytic material for removing tannery dyes from aqueous solutions by adsorption/photocatalysis. [ABSTRACT FROM AUTHOR]

High-porosity monolithic composite aerogels of syndiotactic polystyrene (sPS) and poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) containing reduced graphene oxide (r-GO) were prepared and characterized. The composite aerogels obtained by supercritical carbon dioxide (scCO2) extraction of sPS/r-GO and PPO/r-GO gels were characterized by a fibrillar morphology, which ensured good handling properties. The polymer nanoporous crystalline phases obtained within the aerogels led to high surface areas with values up to 440 m2 g−1. The role of r-GO in aerogels was studied in terms of catalytic activity by exploring the oxidation capacity of composite PPO and sPS aerogels toward benzyl alcohol in diluted aqueous solutions. The results showed that, unlike sPS/r-GO aerogels, PPO/r-GO aerogels were capable of absorbing benzyl alcohol from the diluted solutions, and that oxidation of c.a. 50% of the sorbed benzyl alcohol molecules into benzoic acid occurred. [ABSTRACT FROM AUTHOR]

[Display omitted] • Guest-induced transitions between α and β Nanoporous-Crystalline (NC) forms of PPO. • Both α → β and β → α transitions occur with complete loss of crystalline phase orientation. • Loss of orientation rules out the hypothesis of a continuum of modifications between two phases (α and β). • Lists of α and β guests being suitable to induce β → α and α → β transitions, respectively. • Guest suitable to induce transitions between the two NC phases are good PPO solvents. Nanoporous-crystalline (NC) α and β forms of Poly(2,6-dimethyl-1,4-phenylene) oxide (PPO), exhibit two different large helix conformations, both being suitable for intrahelical low-molecular-mass guest inclusion. α → β and β → α transitions can be achieved by sorption of liquid β-guests and α-guests (i.e., of guest inducing β and α forms by solution casting and by sorption in amorphous PPO), respectively. Both α → β and β → α transitions occur with complete loss of possibly present crystalline phase orientations (both axial and planar). Moreover, the reported data show that transitions between the two phases and the associated loss of crystalline phase orientation occur only for guests being good PPO solvents. These observations rule out the possibility of solid–solid transitions while can be rationalized by mechanisms involving a local dissolution of the NC phases. This local polymer dissolution is followed by host/guest co-crystallization with the helical conformation being different from the starting one and more suitable to host the used guest. These data fully confirm complete separation between the two NC phases while rule out the hypothesis of a continuum of NC phases between two limit ones. [ABSTRACT FROM AUTHOR]

• The application of a new phosphonium-carbon-based phase-transfer catalyst (PTC) synthetized by mechanochemical approach is studied. • The new heterogeneous PTC is fully characterized and used for S N 2 type reaction of NaSCN with variously substituted benzyl bromides. • Using 5mol% catalyst in water can result in over 99% conversion of the reaction. • Being heterogeneous, the phosphonium-carbon-based PTC catalyst can be easily recovered in an aqueous solution and recycled without any loss in efficiency even after five runs. The use of phosphonium-carbon-based PTC as a catalyst in water solution is here described and its performances are discussed. The synthesis is realized via a mechanochemical process in solvent-free conditions respecting most of the green metrics for a sustainable procedure. The heterogeneous phase-transfer catalyst is fully characterized and used for S N 2-type reaction of NaSCN with variously substituted benzyl bromides. The reaction proceeds with high efficiency in the presence of 5mol% of catalyst in water up to >99% of conversion. The catalyst can be easily recycled without losing productivity providing a green procedure. [Display omitted] [ABSTRACT FROM AUTHOR]

• Carbon black intercalation compound was used for the first time as heterogeneous phase-transfer-catalyst for S N 2 type reaction. • An unprecedent efficient nucleophilic substitution was reported in water solution in presence of the new catalyst, providing 95% yield. • This new green approach is able to ensure a very simple procedure with easy handling catalyst, good efficiency and simple product recovery. • The heterogenous catalyst can be recovered and recycled without losing in efficiency. Carbon black intercalation compound was used for the first time as a heterogeneous phase-transfer-catalyst for S N 2 type reaction of NaSCN with 4-nitrobenzyl bromide. The reaction proceeds in the presence of 5 mol% of catalyst with high efficiency in a liquid-liquid biphasic system (CHCl 3 /H 2 O), providing 98% conversion after only 4 h. Furthermore, an unprecedent efficient nucleophilic substitution was reported in water solution in the presence of the new catalyst, providing 95% yield in 8 h. The reaction is green, and the heterogeneous catalyst can be recovered and recycled without losing efficiency. [Display omitted] [ABSTRACT FROM AUTHOR]

This work is focused on the surface characterization of reduced graphene oxide (rGO) obtained through reduction of graphite oxide. The reduction was performed using a green method (based on UV irradiation under N 2 ) with low environmental impact, free of additional functionalization reagents, simple and low-cost. X-ray photoelectron spectroscopy (XPS) was applied for chemical characterization of surface C species showing a significant reduction of oxygen-containing functional groups from the surface of rGO. [ABSTRACT FROM AUTHOR]

Abstract: The vinylogous aldol-type addition of a dienolsilyl ether, derived from 2,2,6-trimethyl-4H-1,3-dioxin-4-one, showed to occur with complete γ-selectivity by enolate activation promoted by neutral Lewis bases under solvent-free conditions. Moderate to high yields were obtained with aromatic, hetero-aromatic, and aliphatic aldehydes, as well as activated ketones. Under the same conditions and in the absence of catalyst, the first Mukaiyama–Michael addition of the masked acetoacetate ester to α,β-unsaturated aldehydes took place in satisfactory way. [Copyright &y& Elsevier]

Abstract: The first enantioselective Michael addition of aniline to chalcones was promoted by cheap and commercially available chincona alkaloids under solvent-free conditions. Variously substituted chalcones were examined as substrates giving the conjugate adducts in moderate to good enantioselectivity. The simple experimental procedure had no work-up and short reaction times, which are the notable advantages. [Copyright &y& Elsevier]