Synthesis and Characterization of Graphene Oxide Derivatives via Functionalization Reaction with Hexamethylene Diisocyanate

Graphene oxide (GO), the oxidized form of graphene, shows unique properties including high mechanical strength, optical transparency, amphiphilicity and surface functionalization capability that make it attractive in fields ranging from medicine to optoelectronic devices and solar cells. However, its insolubility in non-polar and polar aprotic solvents hinders some applications. To solve this issue, novel functionalization strategies are pursued. In this regard, this study deals with the preparation and characterization of hexamethylene diisocyanate (HDI)-functionalized GO. Different reaction conditions were tested to optimize the functionalization degree (FD), and detailed characterizations were conducted via elemental analysis, Fourier-transformed infrared (FT-IR) and Raman spectroscopies to confirm the success of the functionalization reaction. The morphology of HDI-GO was investigated by transmission electron microscopy (TEM), which revealed an increase in the flake thickness with increasing FD. The HDI-GO showed a more hydrophobic nature than pristine GO and could be suspended in polar aprotic solvents such as N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP) and dimethyl sulfoxide (DMSO) as well as in low polar/non-polar solvents like tetrahydrofuran (THF), chloroform and toluene; further, the dispersibility improved upon increasing FD. Thermogravimetric analysis (TGA) confirmed that the covalent attachment of HDI greatly improves the thermal stability of GO, ascribed to the crosslinking between adjacent sheets, which is interesting for long-term electronics and electrothermal device applications. The HDI-GO samples can further react with organic molecules or polymers via the remaining oxygen groups, hence are ideal candidates as nanofillers for high-performance GO-based polymer nanocomposites

Effect of a nutritional intervention based on an energy-reduced Mediterranean diet on environmental impact

[EN]To estimate the environmental impact of a dietary intervention based on an energy-reduced Mediterranean diet (MedDiet) after one year of follow-up. Methods Baseline and 1-year follow-up data were used for 5800 participants aged 55–75 years with metabolic syndrome in the PREDIMED-Plus study. Food intake was estimated through a validated semiquantitative food consumption frequency questionnaire, and adherence to the MedDiet was estimated through the Diet Score. Using the EAT-Lancet Commission tables we assessed the influence of dietary intake on environmental impact (through five indicators: greenhouse gas emissions (GHG), land use, energy used, acidification and potential eutrophication). Using multivariable linear regression models, the association between the intervention and changes in each of the environmental factors was assessed. Mediation analyses were carried out to estimate to what extent changes in each of 2 components of the intervention, namely adherence to the MedDiet and caloric reduction, were responsible for the observed reductions in environmental impact. Results We observed a significant reduction in the intervention group compared to the control group in acidification levels (−13.3 vs. -9.9 g SO2-eq), eutrophication (−5.4 vs. -4.0 g PO4-eq) and land use (−2.7 vs. -1.8 m2). Adherence to the MedDiet partially mediated the association between intervention and reduction of acidification by 15 %, eutrophication by 10 % and land use by 10 %. Caloric reduction partially mediated the association with the same factors by 55 %, 51 % and 38 % respectively. In addition, adherence to the MedDiet fully mediated the association between intervention and reduction in GHG emissions by 56 % and energy use by 53 %.SIPublicación en abierto financiada por el Consorcio de Bibliotecas Universitarias de Castilla y León (BUCLE), con cargo al Programa Operativo 2014ES16RFOP009 FEDER 2014-2020 DE CASTILLA Y LEÓN, Actuación:20007-CL - Apoyo Consorcio BUCL

Impact of mediterranean diet promotion on environmental sustainability: a longitudinal analysis

[EN]This article aims to estimate the differences in environmental impact (greenhouse gas [GHG] emissions, land use, energy used, acidification and potential eutrophication) after one year of promoting a Mediterranean diet (MD). Methods Baseline and 1-year follow-up data from 5800 participants in the PREDIMED-Plus study were used. Each participant's food intake was estimated using validated semi-quantitative food frequency questionnaires, and the adherence to MD using the Dietary Score. The influence of diet on environmental impact was assessed through the EAT-Lancet Commission tables. The influence of diet on environmental impact was assessed through the EAT-Lancet Commission tables. The association between MD adherence and its environmental impact was calculated using adjusted multivariate linear regression models.SIPublicación en abierto financiada por el Consorcio de Bibliotecas Universitarias de Castilla y León (BUCLE), con cargo al Programa Operativo 2014ES16RFOP009 FEDER 2014-2020 DE CASTILLA Y LEÓN, Actuación:20007-CL - Apoyo Consorcio BUCL

Nemateriālo aktīvu grāmatvedības metodoloģiskās problēmas Latvijas Republikā

Nonfluorinated hydrophobic surfaces are of interest for reduced cost, toxicity, and environmental problems. Searching for such surfaces together with versatile processing, A200 silica nanoparticles are modified with an oligodimethylsiloxane and used by themselves or with a polymer matrix. The goal of the surface modification is controlled aggregate size and stable suspensions. Characterization is done by NMR, microanalysis, nitrogen adsorption, and dynamic light scattering. The feasibility of the concept is then demonstrated. The silica aggregates are sprayed in a scalable process to form ultrahydrophobic and imperceptible coatings with surface topographies of controlled nanoscale roughness onto different supports, including nanofibrillated cellulose. To improve adhesion and wear properties, the organosilica was mixed with polymers. The resulting composite coatings are characterized by FE-SEM, AFM, and contact angle measurements. Depending on the nature of the polymer, different functionalities can be developed. Poly­(methyl methacrylate) leads to almost superhydrophobic and highly transparent coatings. Composites based on commercial acrylic car paint show “pearl-bouncing” droplet behavior. A light-emitting polyfluorene is synthesized to prepare luminescent and water repellent coatings on different supports. The interactions between polymers and the organosilica influence coating roughness and are critical for wetting behavior. In summary, the feasibility of a facile, rapid, and fluorine-free hydrophobization concept was successfully demonstrated in multipurpose antiwetting applications

Preparación de complejos de paladio, níquel y oro heterogeneizados sobre óxidos inorgánicos mesoporosos estructurados. Estudio catalítico en reacciones de hidrogenación y formación de enlace C-C

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Química Inorgánica. Fecha de lectura: 25-11-200

The role of mesoporosity and Si/Al ratio in the catalytic etherification of glycerol with benzyl alcohol using ZSM-5 zeolites

A comparative study of the influence of three different acid solids as catalysts (conventional zeolites Z15c with Si/Al = 19.5 and Z40c with Si/Al = 48.2, and a hierarchical zeolite Z40c-H with Si/Al = 50.0) for the etherification of glycerol with benzyl alcohol was performed. The catalytic activity and selectivity of these zeolites was elucidated at different catalyst contents. Three different ethers (3-benzyloxy-1,2-propanediol, which is a mono-benzyl-glycerol ether (MBG) and 1,3-dibenzyloxy-2-propanol, which is a di-benzyl-glycerol ether (DBG) and dibenzyl ether (DBz) were identified as the main products. MBG was the major product of the reaction catalyzed by the microporous Z15c zeolite with low Si/Al molar ratio, whereas DBG was formed in higher yield with the use of microporous Z40c and hierarchical Z40c-H zeolites, both of them having a similar high Si/Al molar ratio (≈50). MBG is a value-added product and it is obtained with good yield and selectivity when using the conventional zeolite Z15c as a catalyst. Under the best conditions tested, i.e., 25 mg of catalyst for 8 h at 120 °C, a 62% of conversion was obtained without the need of solvent, with an excellent 84% selectivity toward the MBG and no formation of DBz.Rafael Luque and Camino González-Arellano gratefully acknowledge support from the Spanish MICINN via the concession of a Ramon y Cajal contract (refs. RYC 2009‑04199 and RYC 2010-06268, respectively). Rafael Luque gratefully acknowledges funding from MICINN under project CTQ2011-28954-C02-02. J.G.M. gratefully acknowledges funding under project PCIN-2013-164 (MINECO and UE). Both R.L. and J.G.M. acknowledge support from MICINN under cooperation project CTQ2011-28954

Synthesis and characterization of chiral bidentate bis(N-heterocyclic carbene)-carboxylate palladium and nickel complexes

Complexes [Pd{(S)-NHCMes,R}2] (R = Me, 2a; iPr, 2b; iBu, 2c) and [Pd{(R)-NHCMes,Me}2] (2a’) were prepared by reaction of the corresponding imidazolium precursor [ImMes,R] (namely (S)–2-alkyl(3-mesityl-1H-imidazol-3- ium-1-yl)acetate, 1a-c, and (R)-2-methyl(3-mesityl-1H-imidazol-3-ium-1-yl)acetate, 1a’), with Ag2O and sub- sequent interaction with Pd(OAc)2, under appropriate conditions. Alternatively, complexes 2 were also obtained by treating compounds [ImMes,R], 1, with an in-situ prepared lithium diisopropylamide solution and then reaction with [Pd(OAc)2]. On the other hand, the nickel complex [Ni{(S)-NHCMes,iPr}2], 3b, was synthesized by the interaction of the complex [NiCp2] (Cp = η5-C5H5) with [ImMes,iPr], 1b, in THF. If this reaction was carried out in acetonitrile, a mixture of complex 3b and the cyclopentadienyl monocarbene complex [NiCp{(S)-NHCMes,iPr}], 4b, was obtained. Similarly to 2b, compound 3b was also prepared by the in-situ formation of the carbene [(S)– NHCMes,iPr]- and then reaction with [NiBr2(dme)] (dme = 1,2-dimethoxyethane). Complexes 2, 3 and 4 were obtained with good yields and fully characterized by analytical (HR-ESI and microanalysis), spectroscopic (IR, 1H and 13C NMR and polarimetry) and X-ray methods (2c). In the solid state, 2c is a square planar complex con- taining two [(S)-NHCMes,iBu]- ligands coordinated in a κ2-C,O fashion, where the carbene and carboxylate donors have the expected trans configuration. The existence of two possible conformers of complexes 2 and 3 was analyzed using DFT methods.Ministerio de Ciencia e Innovación de España-PGC2018-093443-B-I00 y PID2020-114637GB-I00La Universidad de Sevilla y la Universidad de Alcalá-CCG20/CC-003Comunidad de Madrid-EPU-INV/2020/01