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Core−shell nanocomposites comprising barium titanate, BaTiO3 (BTO), and poly(methyl methacrylate) (PMMA) chains grafted from its surface with varied grafting densities were prepared. BTO nanocrystals are high-k inorganic materials, and the obtained nanocomposites exhibit enhanced dielectric permittivity, as compared to neat PMMA, and a relatively low level of loss tangent in a wide range of frequencies. The impact of the molecular dynamics, structure, and interactions of the BTO surface on the polymer chains was investigated. The nanocomposites were characterized by broadband dielectric and vibrational spectroscopies (IR and Raman), transmission electron microscopy, differential scanning calorimetry, and nuclear magnetic resonance. The presence of ceramic nanoparticles in core–shell composites slowed down the segmental dynamic of PMMA chains, increased glass transition temperature, and concurrently increased the thermal stability of the organic part. It was also evidenced that, in addition to segmental dynamics, local β relaxation was affected. The grafting density influenced the self-organization and interactions within the PMMA phase, affecting the organization on a smaller size scale of polymeric chains. This was explained by the interaction of the exposed surface of nanoparticles with polymer chains.

In this article, we describe the antimicrobial properties of a new composite based on anodic aluminium oxide (AAO) membranes containing propyl-copper-phosphonate units arranged at a predetermined density inside the AAO channels. The samples were prepared with four concentrations of copper ions and tested as antimicrobial drug on four different strains of Escherichia coli (K12, R2, R3 and R4). For comparison, the same strains were tested with three types of antibiotics using the minimal inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) tests. Moreover, DNA was isolated from the analysed bacteria which was additionally digested with formamidopyrimidine-DNA glycosylase (Fpg) protein from the group of repair glycosases. These enzymes are markers of modified oxidised bases in nucleic acids produced during oxidative stress in cells. Preliminary cellular studies, MIC and MBC tests and digestion with Fpg protein after modification of bacterial DNA suggest that these compounds may have greater potential as antibacterial agents than antibiotics such as ciprofloxacin, bleomycin and cloxacillin. The described composites are highly specific for the analysed model Escherichia coli strains and may be used in the future as new substitutes for commonly used antibiotics in clinical and nosocomial infections in the progressing pandemic era. The results show much stronger antibacterial properties of the functionalised membranes on the action of bacterial membranes in comparison to the antibiotics in the Fpg digestion experiment. This is most likely due to the strong induction of oxidative stress in the cell through the breakdown of the analysed bacterial DNA. We have also observed that the intermolecular distances between the functional units play an important role for the antimicrobial properties of the used material. Hence, we utilised the idea of the 2D solvent to tailor them.

An enzymatic route for phosphorous–carbon bond formation was developed by discovering new promiscuous activity of lipase. We reported a new metal-free biocatalytic method for the synthesis of pharmacologically relevant β-phosphonomalononitriles via a lipase-catalyzed one-pot Knoevenagel–phospha–Michael reaction. We carefully analyzed the best conditions for the given reaction: the type of enzyme, temperature, and type of solvent. A series of target compounds was synthesized, with yields ranging from 43% to 93% by enzymatic reaction with Candida cylindracea (CcL) lipase as recyclable and, a few times, reusable catalyst. The advantages of this protocol are excellent yields, mild reaction conditions, low costs, and sustainability. The applicability of the same catalyst in the synthesis of β-phosphononitriles is also described. Further, the obtained compounds were validated as new potential antimicrobial agents with characteristic E. coli bacterial strains. The pivotal role of such a group of phosphonate derivatives on inhibitory activity against selected pathogenic E. coli strains was revealed. The observed results are especially important in the case of the increasing resistance of bacteria to various drugs and antibiotics. The impact of the β-phosphono malonate chemical structure on antimicrobial activity was demonstrated. The crucial role of the substituents attached to the aromatic ring on the inhibitory action against selected pathogenic E. coli strains was revealed. Among tested compounds, four β-phosphonate derivatives showed an antimicrobial activity profile similar to that obtained with currently used antibiotics such as ciprofloxacin, bleomycin, and cloxacillin. In addition, the obtained compounds constitute a convenient platform for further chemical functionalization, allowing for a convenient change in their biological activity profile. It should also be noted that the cost of the compounds obtained is low, which may be an attractive alternative to the currently used antimicrobial agents. The observed results are especially important because of the increasing resistance of bacteria to various drugs and antibiotics.

An efficient method for the synthesis of functionalized peptidomimetics via multicomponent Ugi reaction has been developed. The application of trifluoroethanol (TFE) as a reaction medium provided desired products with good yields. Further, using the developed cyclisation reaction, the obtained peptidomimetics were transformed into the cyclic analogues (diketopiperazines, DKPs). The goal of the performed studies was to revised and compare whether the structure of the obtained structurally flexible acyclic peptidomimetics and their rigid cycling analogue DKPs affect antimicrobial activity. We studied the potential of synthesized peptidomimetics, both cyclic and acyclic, as antimicrobial drugs on model E. coli bacteria strains (k12, R2–R4). The biological assays reveal that DKPs hold more potential as antimicrobial drugs compared to open chain Ugi peptidomimetics. We believe that it can be due to the rigid cyclic structure of DKPs which promotes the membrane penetration in the cell of studied pathogens. The obtained data clearly indicate the high antibiotic potential of synthesized diketopiperazine derivatives over tested antibiotics.

The macrocyclic structures with local conjugation readily undergo a redox-triggered change in the diatropic character, leading to a global current-density pathway of the doubly charged systems. The figure-eight geometry of the neutral dimer does not significantly change upon oxidation according to the spectroscopic and computational data. The oxidation leads to 3D cross-conjugation at the intersection of the two ethylene bridges resulting in a global ring current.

In this article, we describe the antimicrobial properties of pristine anodised aluminium oxide matrices—the material many consider biologically inert. During a typical anodisation process, chromium and chlorine compounds are used for electropolishing and the removal of the first-step aluminium oxide. Matrices without the use of those harmful compounds were also fabricated and tested for comparison. The antibacterial tests were conducted on four strains of Escherichia coli: K12, R2, R3 and R4. The properties of the matrices were also compared to the three types of antibiotics: ciprofloxacin, bleomycin and cloxacillin using the Minimal Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) tests. Moreover, DNA was isolated from the analysed bacteria which was additionally digested with formamidopyrimidine-DNA glycosylase (Fpg) protein from the group of repair glycosases. These enzymes are markers of modified oxidised bases in nucleic acids produced during oxidative stress in cells. Preliminary cellular studies, MIC and MBC tests and digestion with Fpg protein after modification of bacterial DNA suggest that these compounds may have greater potential as antibacterial agents than the aforementioned antibiotics. The described composites are highly specific for the analysed model Escherichia coli strains and may be used in the future as new substitutes for commonly used antibiotics in clinical and nosocomial infections in the progressing pandemic era. The results show much stronger antibacterial properties of the functionalised membranes on the action of bacterial membranes in comparison to the antibiotics in the Fpg digestion experiment. This is most likely due to the strong induction of oxidative stress in the cell through the breakdown of the analysed bacterial DNA.

This work presents the processing of a high-acidity oil through sequential reactions of esterification using montmorillonite K10 and transesterification using zinc monoglycerolate. Since these solids had not been employed along with this approach beforehand, the objective of this work is to provide a general insight of the proposed process and demonstrate its technical feasibility. In this sense, the processing of a synthetic mixture containing soybean oil and lauric acid provided a reduction of the free fatty acid content from (40.8±0.1) % to (3.1±0.4) % after the esterification reaction and a fatty acid methyl ester yield of (95.4±0.2) % was obtained after the transesterification reaction. As compared to traditional homogeneous catalysts, the solid catalysts employed in this work require higher reaction times to achieve satisfactory ester yields but, on the other hand, they are less sensitive to the presence of both water and free fatty acids in the raw materials and can be easily recovered and reused. Therefore, the results accomplished may help the development of a technology for processing high-acidity fatty materials in order to obtain biodiesel, although its economic feasibility still needs a further assessment.

The impact of substituent at phenyl ring of diethyl benzylphosphonate derivatives on cytotoxic activity was studied. The organophosphonates were obtained based on developed palladium-catalyzed α, β-homodiarylation of vinyl esters protocol. The new synthetic pathway toward 1,2-bis(4-((diethoxyphosphoryl)methyl)phenyl)ethyl acetate was proposed which significantly improves the overall yield of the final product (from 1% to 38%). Several newly synthesized organophosphonates were tested as new potential antimicrobial drugs on model Escherichia coli bacterial strains (K12 and R2-R3). All tested compounds show the highest selectivity and activity against K12 and R2 strains. Preliminary cellular studies using MIC and MBC tests and digestion of Fpg after modification of bacterial DNA suggest that selected benzylphosphonate derivatives may have greater potential as antibacterial agents than typically used antibiotics such as ciprofloxacin, bleomycin and cloxacillin. These compounds are highly specific for pathogenic E. coli strains based on the model strains used and may be engaged in the future as new substitutes for commonly used antibiotics, which is especially important due to the increasing resistance of bacteria to various drugs and antibiotics.

At this time, the development of advanced elastic dielectric materials for use in organic devices, particularly in organic field-effect transistors, is of considerable interest to the scientific community. In the present work, flexible poly(dimethylsiloxane) (PDMS) specimens cross-linked by means of ZnCl2-bipyridine coordination with an addition of 0.001 wt. %, 0.0025 wt. %, 0.005 wt. %, 0.04 wt. %, 0.2 wt. %, and 0.4 wt. % of gold nanoparticles (AuNPs) were prepared in order to understand the effect of AuNPs on the electrical properties of the composite materials formed. The broadband dielectric spectroscopy measurements revealed one order of magnitude decrease in loss tangent, compared to the coordinated system, upon an introduction of 0.001 wt. % of AuNPs into the polymeric matrix. An introduction of AuNPs causes damping of conductivity within the low-temperature range investigated. These effects can be explained as a result of trapping the Cl− counter ions by the nanoparticles. The study has shown that even a very low concentration of AuNPs (0.001 wt. %) still brings about effective trapping of Cl− counter anions, therefore improving the dielectric properties of the investigated systems. The modification proposed reveals new perspectives for using AuNPs in polymers cross-linked by metal-ligand coordination systems.

Understanding how making structural changes in small molecules affects their binding affinities for targeted proteins is central to improving strategies for rational drug design. To assess the effects of varying the nature of nonpolar groups upon binding entropies and enthalpies, we designed and prepared a set of Grb2-SH2 domain ligands, Ac–pTyr–Ac6c–Asn–(CH2)n–R, in which the size and electrostatic nature of R groups at the pTyr+3 site were varied. The complexes of these ligands with the Grb2-SH2 domain were evaluated in a series of studies in which the binding thermodynamics were determined using isothermal titration calorimetry, and binding interactions were examined in crystallographic studies of two different complexes. Notably, adding nonpolar groups to the pTyr+3 site leads to higher binding affinities, but the magnitude and energetic origins of these effects vary with the nature of the R substituent. For example, enhancements to binding affinities using aliphatic R groups are driven by more favorable changes in binding entropies, whereas aryl R groups improve binding free energies through a combination of more favorable changes in binding enthalpies and entropies. However, enthalpy/entropy compensation plays a significant role in these associations and mitigates against any significant variation in binding free energies, which vary by only 0.8 kcal•mol−1, with changes in the electrostatic nature and size of the R group. Crystallographic studies show that differences in ΔG° or ΔH° correlate with buried nonpolar surface area, but they do not correlate with the total number of polar or van der Waals contacts. The relative number of ordered water molecules and relative order in the side chains at pTyr+3 correlate with differences in –TΔS°. Overall, these studies show that burial of nonpolar surface can lead to enhanced binding affinities arising from dominating entropy- or enthalpy-driven hydrophobic effects, depending upon the electrostatic nature of the apolar R group.

Синтезовано ізопропілаурат з викорис- танням як каталізатора суміші оксидів металів. Найвищу кон- версію отримано за таких умов: 393 К, молярне співвідно- шення ізопропанол:лауринова кислота 10:1, склад каталіза- тора 33 % CuO, 33 % Ag2O і 33 % Al2O3, співвідношення каталізатор/лауринова кислота становить 8 мас %, час реакції 2 год. Показано, що оксиди каталізатора після естерифікації не перетворюються в інші речовини. This paper reports the synthesis of isopropyl laurate while using a mixture of metal oxides as a catalyst. The best conversion value was obtained in the following conditions: 393 K, isopropanol:lauric acid molar ratio is10:1, composition of the catalyst is 33 % CuO, 33%Ag2O and 33 % Al2O3, catalyst/lauric acid ratio is 8%(w/w), and reaction time 2 h. Isolation of the catalysts after esterification showed that the oxides were not converted into other materials.

DFT calculations with periodic boundary conditions were performed in order to study the esterification/transesterification mechanisms involved in the biodiesel production. The simulation of the adsorptions of acetic acid, methanol and triacetin was carried out on zinc acetate as the catalyst. The adsorption energies of these processes could be obtained and PDOS of the zinc sites and the carboxylate group carbons of the acetic acid and the triacetin were explored for the evaluation of their acidity. The adsorption energies and the reaction barrier of the alkoxide formation showed that the triglyceride adsorption is very likely to occur first in transesterification processes. The barriers also denote that an alkoxide formation from the methanol is not favored and, consequently, a nucleophilic attack from the methanol molecule occurs.

This study reports an assessment of free fatty acid esterification reactions with ethanol using montmorillonite K10 as catalyst, a commercial solid catalyst known for having high performance in several catalytic processes. Therefore, the main objective of this work is to perform reactions of FFA (lauric, stearic and oleic acids) ethyl esterification, checking how different chain lengths and unsaturation presence affect the reaction kinetics. The catalyst was characterized by different techniques, in which the structure and acidic properties were evaluated. Esterification reactions were systematically evaluated by a factorial design (effects of temperature, molar ratio and catalyst content) to determine optimal conditions to be used in the reaction kinetics study. In addition, kinetics reactions without montmorillonite K10 were also carried out in order to evaluate the autocatalytic (or thermal) reaction contribution. The kinetic data obtained for all FFAs was used to adjust kinetic parameters and the model was capable to correlate the experimental data, providing values of the root mean square deviation (rmsd) around 3.5% in terms of fatty acid conversions. The low values obtained for the rmsd indicate the possibility to achieve a reactor design to process complex fatty matrices using data generated for a pure FFA without quality loss. Furthermore, due to the high activity presented in the free fatty acid esterification under the studied conditions, montmorillonite K10 proves to be a suitable catalyst for industrial-scale biodiesel obtention from raw materials with high content of free fatty acids.

Thermodynamic parameters were determined for structurally-related inhibitors of HCV NS3 protease to assess how binding entropies and enthalpies vary with incremental changes at the P2 and P3 inhibitor subsites. Changing the heterocyclic substituent at P2 from a pyridyl to a 7-methoxy-2-phenyl-4-quinolyl group leads to a 710-fold increase in affinity. Annelating a benzene ring onto a pyridine ring leads to quinoline-derived inhibitors having higher affinities, but the individual enthalpy and entropy contributions are markedly different for each ligand pair. Introducing a phenyl group at C2 of the heterocyclic ring at P2 uniformly leads to higher affinity analogs with more favorable binding entropies, while adding a methoxy group at C7 of the quinoline ring at P2 provides derivatives with more favorable binding enthalpies. Significant enthalpy/entropy compensation is observed for structural changes made to inhibitors lacking a 2-phenyl substituent, whereas favorable changes in both binding enthalpies and entropies accompany structural modifications when a 2-phenyl group is present. Overall, binding energetics of inhibitors having a 2-phenyl-4-quinolyl group at P2 are dominated by entropic effects, whereas binding of the corresponding norphenyl analogs are primarily enthalpy driven. Notably, the reversal from an entropy driven association to an enthalpy driven one for this set of inhibitors also correlates with alternate binding modes. When the steric bulk of the side chain at P3 is increased from a hydrogen atom to a tert-butyl group, there is a 770-fold improvement in affinity. The 30-fold increase resulting from the first methyl group is solely the consequence of a more favorable change in entropy, whereas subsequent additions of methyl groups leads to modest increases in affinity that arise primarily from incremental improvements in binding enthalpies accompanied with smaller favorable entropic contributions.

In this research work, ternary (Mg + Zn:Al; M2+:M3+ = 2:1) layered double hydroxides (LDH) intercalated with nitrate and p-aminobenzoate anions were synthesized through the co­precipitation method at constant alkaline pH. These materials were characterized by several instrumental techniques and used as functional fillers in low-density polyethylene (LDPE), obtaining homogeneous nanocomposites by means of injection molding. In the samples prepared with percentages of 0.5, 2, 4, 6 and 10% by weight in relation to LDPE, maintenance or slight improvement of the mechanical properties was observed for all samples. In the LDPE nanocomposites the UV absorption showed to be higher than neat polyethylene. Weathering experiments performed with the neat LDPE and LDPE nanocomposites containing 5% of maleic anhydride and 5% of LDH intercalated with p­aminobenzoate demonstrated a decrease of oxidation product generated due to ultraviolet radiation absorption because the organic intercalated specie, indicating that the ternary LDH is a potential filler to protect polymers from UV radiation degradation.

Summary Low molar mass homopolymers, synthesized through free radical polymerization of acrylic acid under solvent control were reported. The polymers were characterized by FTIR, NMR, TGA, and GPC. The behavior as pour point improvers in biodiesel and blends biodiesel/diesel, were evaluated. By using 1000 ppm of the poly(tetradecyl acrylate) (A14) it was possible to decrease the pour point (PP) of neat biodiesel to −10°C, blend B5 to −39°C and blend B20 to −28°C, values below those reported in the literature. These results indicated that it would be possible to use higher amount of biodiesel in blends with diesel in regions where their use would not be feasible, mainly because of their poor flow properties.

This work reports a kinetic study of catalyzed esterification of lauric acid with anhydrous ethanol related to biodiesel production. The catalyst consists of a clay mineral (montmorillonite STx1-b) prepared according to procedure previously described in literature. The acid activation was confirmed by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Operating parameters: temperature ( T = 140 and 180 °C), molar ratio ethanol to lauric acid (MR = 6:1 and 12:1) and catalyst loading (CAT = 2 and 10 wt%, in relation to the fatty acid mass) were evaluated as a preliminary study to the kinetics. Temperature is clearly the factor that most contributes to higher conversions of fatty acid, however, its effect was less pronounced with the use of the catalyst. Moreover, reaction kinetic experiments were performed at different conditions ( T = 140, 160 and 180 °C; MR = 3:1, 6:1 and 9:1, CAT = 0, 10 and 20 wt%) as well as kinetics modeling are presented. The Eley–Rideal mechanism with surface reaction between adsorbed ethanol and lauric acid in the bulk as the limiting step was proposed to represent the catalyzed reactions, in which the global reaction rate was expressed as the sum of non-catalyzed (thermal conversion) and catalyzed reactions. From the results presented, it can be seen that the catalyst montmorillonite STx1-b was able to lead the system to high conversions in shorter time when compared to the non-catalyzed reaction.

Cobalt/aluminum and nickel/aluminum layered double hydroxide (LDH - M+2:Al molar ratio of 3:1) were intercalated with dodecylsulphate (DDS), laurate (LAU), stearate (STE) and palmitate (PAL) and used as filler in low-density polyethylene (LDPE) in percentages between 0.2 and 7.0wt%. After injection molding, the samples were submitted to morphological characterization by scanning electron microscopy (SEM), analysis of thermal behavior by differential scanning calorimetry (DSC) and investigation of rheological properties. All Co/Al-LDPE samples showed the formation of a high temperature polymer crystal domain, induced by the LDH filler. The rheological properties indicated in general a reduction of shear modulus due to incompatibility between some regions of LDH and LDPE, which promoted phase separation. However, interaction with the LDH surface indicated higher affinity of the Ni/Al-LDH for the LDPE compared to Co/Al-LDH, forming permanent networks.

This work is focused on the esterification of fatty acids (commercial oleic mix) with zinc carboxylates (layered metal soap). About 25 experiments were performed, with and without catalyst, yielding a kinetic model based on the Eley–Rideal approach, able to predict fatty acid conversions under different conditions (molar ratio fatty acids/ethanol and temperature). An apparent first order reaction with respect to both reactants with no diffusion limitations was proposed. The activation energy of 80 kJ/mol was found. Fatty acid conversion up to 92% was reached under some conditions and the catalytic yields compared to the blank ones reached 40% in less than 90 min of reaction. This catalyst has shown a unique behavior among all other catalysts available for esterification, acting similarly to a homogeneous catalyst during the reaction but being recovered like a heterogenous catalyst at the end of the process.

Synthetic metalloporphyrins are catalysts that can efficiently insert oxygen and other atoms such as nitrogen and sulfur in hydrocarbons and in a wide variety of other organic compounds. This work reports on a synthetic strategy to prepare new metalloporphyrins via structural modification of [5,10,15,20-tetrakis (pentafluorophenyl)porphyrin], or [H 2 (TPFPP)], with 4-mercaptobenzoic acid; it also describes their characterization and catalytic activity. The substituent groups present in the structure of the resulting porphyrins furnished structured solids, which could potentially serve as catalysts in heterogeneous medium. Investigation of the catalytic activity of the new derivatives in the oxidation of (Z)-cyclooctene, cyclohexane, and heptane, under homogeneous conditions, and in the oxidation of (Z)-cyclooctene, in heterogeneous medium, proved that the new metalloporphyrins constituted excellent catalysts for (Z)-cyclooctene epoxidation. As for alkane oxidation, they selectively gave the corresponding alcohol in good yields.

Synthetic strategies that comply with the principles of green chemistry represent a challenge: they will enable chemists to conduct reactions that maximize the yield of products with commercial interest while minimizing by-products formation. The search for catalysts that promote the selective oxidation of organic compounds under mild and environmentally friendly conditions constitutes one of the most important quests of organic chemistry. In this context, metalloporphyrins and analogues are excellent catalysts for oxidative transformations under mild conditions. In fact, their reduced derivatives chlorins are also able to catalyze organic compounds oxidation effectively, although they have been still little explored. In this study, we synthesized two chlorins through porphyrin cycloaddition reactions with 1.3-dipoles and prepared the corresponding manganese chlorins (MnCHL) using adequate manganese(II) salts. These MnCHL were posteriorly immobilized on silica by following the sol–gel process and the resulting solids were characterized by powder X-ray diffraction (PXRD), UVVIS spectroscopy, FTIR, XPS, and EDS. The catalytic activity of the immobilized MnCHL was investigated in the oxidation of cyclooctene, cyclohexene and cyclohexane and the results were compared with the ones obtained under homogeneous conditions.

This work employed [5,10,15,20-tetrakis(pentafluorophenyl)porphyrin] ([H2(TPPF20)], H2P1) as the platform to prepare a tetrasubstituted galactodendritic conjugate porphyrin (H2P3). After metalation with excess copper(II) acetate, H2P3 afforded a new solid porphyrin material, Cu4CuP3S. This work also assessed the ability of the copper(II) complex (CuP3) of H2P3 to coordinate with zinc(II) acetate, to yield the new material Zn4CuP3S. UV-visible, Fourier transform infrared, and electron paramagnetic resonance spectroscopies aided full characterization of the synthesized solids. (Z)-Cyclooctene epoxidation under heterogeneous conditions helped to evaluate the catalytic activity of Cu4CuP3S and Zn4CuP3S. The efficiency of Cu4CuP3S in the oxidation of another organic substrate, catechol, was also investigated. According to the results obtained in the heterogeneous process, Cu4CuP3S mimicked the activity of cytochrome P-450 and catecholase. In addition, Cu4CuP3S was reusable after recovery and reactivation. The data obtained herein were compared with the results achieved for the copper complex (CuP1) of [H2(TPPF20)] and for CuP3 under homogeneous conditions.

To physicochemically characterize and compare monoclonal antibody (mAb) solutions containing aggregates generated via metal catalyzed oxidation (MCO).Two monoclonal IgG2s (mAb1 and mAb2) and one monoclonal IgG1 (rituximab) were exposed to MCO with the copper/ascorbic acid oxidative system, by using several different methods. The products obtained were characterized by complementary techniques for aggregate and particle analysis (from oligomers to micron sized species), and mass spectrometry methods to determine the residual copper content and chemical modifications of the proteins.The particle size distribution and the morphology of the protein aggregates generated were similar for all mAbs, independent of the MCO method used. There were differences in both residual copper content and in chemical modification of specific residues, which appear to be dependent on both the protein sequence and the protocol used. All products showed a significant increase in the levels of oxidized His, Trp, and Met residues, with differences in extent of modification and specific amino acid residues modified.The extent of total oxidation and the amino acid residues with the greatest oxidation rate depend on a combination of the MCO method used and the protein sequence.

The esterification of lauric and stearic acids, tall oil fatty acid, and a commercial oleic acid with methanol was investigated using an acid-activated standard montmorillonite (AASM) as a catalyst. Reaction variables such as the methanol:fatty acid molar ratio, catalyst content, and temperature were evaluated. Comparative reactions were performed with K10 catalyst, and similar or even better results were obtained with AASM, indicating that this could be employed as a suitable Lewis/Bronsted esterification catalyst. The experimental results obtained for the esterification of lauric acid with methanol were compared to a thermodynamic model. For this purpose, the UNIFAC model was used for the activity coefficient calculation for components in the nonideal mixture. This model has shown that the catalytic system was able to drive the reaction to equilibrium within 2 h, and this was confirmed by comparing the experimental results with thermodynamic predictions.

This work report experimental kinetic data of ethyl esters production from auto-thermal esterification of lauric acid with ethanol and also using zinc laurates (ZnL2) as catalyst. The experiments were performed in a mechanically stirred reactor evaluating the effect of temperature (120–250 °C), ethanol to lauric acid molar ratio (MR) (3:1–9:1) and catalyst amount (2–10 wt%). Chemical equilibrium calculation using a non-ideal mixture approach was applied to perform a thermodynamic analysis of this esterification reaction at the equilibrium conditions. The UNIFAC-LV model was used for the activity coefficient calculations. The results showed that relative high lauric acid conversions can be obtained (around 92% of lauric acids ethyl esters – LAEE) even employing hydrated ethanol. Furthermore, the results showed that the catalyst was able to drive the reaction to the equilibrium in a relative short time (about 100 min).

O presente trabalho descreve a síntese e caracterização de hidróxidos duplos lamelares (HDL) de Zn/Al na razão molar 2:1, os quais foram intercalados com íons cloreto hidratados e ânions derivados dos corantes azo alaranjado de metila (AM) e alaranjado II (AII). Após caracterização, os materiais foram utilizados como cargas em polietileno de alta densidade (PEAD) e nanocompósitos foram preparados por extrusão e injeção, seguindo a norma ASTM D638-10. Os teores de cargas variaram de 0,1 até 2% (incluindo-se os sais de sódio dos corantes) e os nanocompósitos homogêneos foram avaliados em relação as suas propriedades estruturais, térmicas e mecânicas. De modo geral, após a adição das cargas existe somente uma pequena influência na temperatura de fusão e cristalização do PEAD. Para os HDLs contendo o pigmento intercalado com o ânion do corante AM e sais de sódio de ambos os corantes, as propriedades mecânicas apresentaram leve aumento do módulo e tensão de ruptura e diminuição do alongamento em relação ao polímero puro e um comportamento inverso foi observado para o ânion AII, além do HDL contendo ânions cloreto hidratados. The present work describes the synthesis and characterization of Zn/Al layered double hydroxides (HDL) in the molar ratio 2:1, which were intercalated with hydrated chlorine ions and anions derived from the azo dyes methylorange (AM) and orange II (AII). After characterization, the materials were used as fillers into high density polyethylene (HDPE) and the nanocomposites were prepared by extrusion and injection, following the norm ASTM D638-10. The filler contents varied from 0.1 to 2% (including the sodium dye salts) and the homogeneous nanocomposites were evaluated in relation to their structural, thermal and mechanical properties. In general, after the fillers' addition there is only a small influence in the melting and crystallization temperature of HDPE. For HDLs intercalated with the anionic dye AM and both sodium dyes, the mechanical properties presented a small influence on Young's modulus and tensile strength and an increase in elongation compared to pure HDPE and an inverse behavior was observed for the anion AII, in addition to the HDL containing hydrated chlorine anions.

The nuclear magnetic resonance (NMR) and dielectric spectroscopy (DS) methods were used to investigate the segmental and global dynamics in lamellar microphase separated poly(styrene-b-isoprene) (SI) diblock copolymer. For the first time, the susceptibility representation of the NMR relaxation data is applied to the analysis of the molecular dynamics in complex polymer systems like the diblock copolymer. This approach in combination with the frequency-temperature superposition (FTS) allows one to compare directly the NMR and DS data in an extended frequency range providing a unique comprehensive picture of various relaxation processes present in the system studied. The findings of these investigations include structural relaxations of the polyisoprene (PI) and the polystyrene (PS) blocks, a normal mode relaxation of the PI block, and an extra low frequency interfacial relaxation. Special attention has been devoted to influence of the copolymer morphology on the segmental and global dynamics in PI.

Layered zinc monoglycerolate was synthesized and investigated in the methyl transesterification of soybean oil. Conversions up to 98 % were obtained at 120 °C and after the fourth cycle of use under the same conditions, the solid preserved its structure, attesting the possibility to apply this material in industrial processes.

Molecular dynamics of miktoarm star copolymers consisting of poly(n-butyl acrylate) PBA and polyethylene oxide (PEO) arms was studied by means of Broadband Dielectric Spectroscopy (BDS) and Nuclear Magnetic Resonance (NMR) methods. The spectroscopic studies were performed for three types of copolymers differing in the composition, namely materials containing 76%, 46% and 16% molar fraction of PBA arms. The local processes, described by the Arrhenius law (e.g. the anisotropic rotation of methyl groups and the anisotropic local motions in the PEO chain), were observed for the studied systems below the glass transition temperature. It was found that the investigated PBA/PEO miktoarm star copolymers are characterized by single glass transition, which may result from similar values of glass transition temperatures of the PBA and PEO polymers. The segmental dynamics in the studied systems was quantitatively described by using the Vogel-Fulcher-Tammann (VFT) relation applied to combined NMR and BDS data. Moreover, above the glass transition temperature the interfacial polarization and conductivity phenomena were detected with the BDS method for all systems under study.

The conversion of lauric acid and fatty acid mixtures to methyl esters was investigated using bismuth-containing solid catalysts obtained from Bi2O3. When the reaction was carried out at 140 °C for 2 h using a methanol:fatty acid molar ratio of 2:1 and 5 wt % of Bi2O3 in relation to the mass of fatty acids, conversions up to 87 wt % were achieved even after four consecutive reaction cycles. Besides the observed catalytic activity, the bismuth-containing solid catalyst was also amenable to recycling for at least four reaction cycles without significant loss of its catalytic performance. However, the analysis of the recovered solids by X-ray diffraction and Fourier transform infrared spectroscopy demonstrated that Bi2O3 was converted to layered bismuth carboxylates, which acted as the actual esterification catalyst. On the basis of these, layered bismuth carboxylates unfold as a suitable catalytic system for the esterification of fatty acids and lipid sources of high acid number.

In this study in situ bulk polymerization of L-lactide filled with layered double hydroxides (LDH) was investigated. Four different LDHs intercalated with two different organic anions (salicylate and sebacate) were synthesized and characterized. After characterization, these synthetic layered compounds were used as fillers in poly(L-lactide) (PLLA) nanocomposites with two different fillers’s loadings (1 wt% and 2 wt%). PLLA and PLLA nanocomposites were evaluated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), ultraviolet and visible spectroscopy, thermogravimetric analysis (TGA), dynamical mechanical analysis (DMA), flexural testing and differential scanning calorimetry (DSC). The results demonstrated that, compared to PLLA, the nanocomposite containing 1 wt% of Zn/Al salicylate transmitted less UVA and UVB light, while keeping a similar transparency in the visible region. Thermogravimetric analysis revealed that the nanocomposite with 1 wt% of Zn/Al salicylate exhibited the highest thermal stability. In general the flexural and dynamical mechanical properties were reduced in compassion to neat PLLA. DSC results, demonstrated that, compared to PLLA, all the nanocomposites exhibited lower glass transition temperature and melting temperature values.

Layered materials are a very interesting class of compounds obtained by stacking of two-dimensional layers along the basal axis. A remarkable property of these materials is their capacity to interact with a variety of chemical species, irrespective of their charge (neutral, cationic or anionic). These species can be grafted onto the surface of the layered materials or intercalated between the layers, to expand or contract the interlayer distance. Metalloporphyrins, which are typically soluble oxidation catalysts, are examples of molecules that can interact with layered materials. This work presents a short review of the studies involving metalloporphyrin immobilization on two different anionic exchangers, Layered Double Hydroxides (LDHs) and Layered Hydroxide Salts (LHSs), published over the past year. After immobilization of anionic porphyrins, the resulting solids behave as reusable catalysts for heterogeneous oxidation processes. Although a large number of publications involving metalloporphyrin immobilization on LDHs exist, only a few papers have dealt with LHSs as supports, so metalloporphyrins immobilized on LHSs represent a new and promising research field. This work also describes new results on an anionic manganese porphyrin (MnP) immobilized on Mg/Al-LDH solids with different nominal Mg/Al molar ratios (2:1, 3:1 and 4:1) and intercalated with different anions (CO₃(2-) or NO₃(-)). The influence of the support composition on the MnP immobilization rates and the catalytic performance of the resulting solid in cyclooctene oxidation reactions will be reported.

The effects of preselected six different layered double hydroxides (LDHs) (Zn/Al 4:1 DDS, Mg/Al 2:1 DDS, Zn/Al 2:1 stearate, Mg/Fe 4:1 stearate, Zn/Al 2:1 laurate, and Mg/Fe 4:1 laurate) on the mechanical, thermal, and fire properties of poly(methyl methacrylate) (PMMA) nanocomposites, synthesized by intercalative in situ bulk polymerization, were evaluated. PMMA nanocomposites containing three different LDH concentrations (1, 3, and 5 wt%) were produced, and it was observed that all the nanocomposites with lower LDH concentration (1 wt%) showed a higher elastic modulus than PMMA. However, as the LDH concentration increased, the elastic modulus decreased for all the nanocomposites. It was shown that PMMA/(Zn/Al 2:1 stearate) containing 5 wt% of LDH in its composition exhibited a decomposition temperature about 97°C higher than pure PMMA. According to this study, it was found that it is possible to enhance some mechanical and thermal properties of PMMA using very low LDH concentrations (mass fraction of LDH equal to 1%). LDHs are inexpensive materials based on abundant metals with a simple synthesis method that has a low environmental impact. © 2012 Wiley Periodicals, Inc. Adv Polym Techn 32: E660–E674, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.21309

Epoxy resins display excellent properties such as high thermal and mechanical stability along with good chemical resistance, but usually perform poorly under fire, burning easily and violently. The focus of the present work is to investigate the use of glycinate intercalated layered double hydroxides (LDH) for the preparation of two-component (LDH) and three-component (LDH/glass fiber) epoxy composites in order to achieve fire retardancy. The solution method was used to synthesize LDH, and the three-component epoxy/LDH/glass fiber composites were molded by resin transfer molding (RTM). The mechanical properties were investigated with tensile, flexural, impact and hardness testing. The flame-retardant characteristics were evaluated by horizontal (UL 94 HB) and vertical burning (UL 94 V), and the burnt sample residues were examined for morphological changes by scanning electron microscopy. The best mechanical performance was obtained when glass fiber (three-component) was used as reinforcement, and all samples containing LDH showed self-extinguishing behavior with lower burning rate than pristine epoxy or epoxy/glass fiber.

Summary: Layered double hydroxides (LDH) are chemical compounds that can be added to polymeric resins to confer fire retardant characteristics. The focus of this work is to study the incorporation of LDH intercalated with dodecylsulfate anions into epoxy resins. The mechanical properties were investigated using tensile, flexural and impact mechanical tests. The flame-retardant properties were assessed using horizontal (UL 94 HB) and vertical burning (UL 94 V) tests. The highest tensile strength was obtained for the composite with 3 wt% of LDH, whereas the highest flexural strength was found by incorporating 1 wt% of LDH. All samples containing LDH showed self-extinguishing behavior in the vertical test and lower burning rate than pristine epoxy.

Purpose To predict precision and other performance characteristics of chromatographic purity methods, which represent the most widely used form of analysis in the biopharmaceutical industry. Methods We have conducted a comprehensive survey of purity methods, and show that all performance characteristics fall within narrow measurement ranges. This observation was used to develop a model called Uncertainty Based on Current Information (UBCI), which expresses these performance characteristics as a function of the signal and noise levels, hardware specifications, and software settings. Results We applied the UCBI model to assess the uncertainty of purity measurements, and compared the results to those from conventional qualification. We demonstrated that the UBCI model is suitable to dynamically assess method performance characteristics, based on information extracted from individual chromatograms. Conclusions The model provides an opportunity for streamlining qualification and validation studies by implementing a “live validation” of test results utilizing UBCI as a concurrent assessment of measurement uncertainty. Therefore, UBCI can potentially mitigate the challenges associated with laborious conventional method validation and facilitates the introduction of more advanced analytical technologies during the method lifecycle. Electronic supplementary material The online version of this article (doi:10.1007/s11095-012-0836-z) contains supplementary material, which is available to authorized users.

Layered double hydroxides (LDH) containing Zn/Al and Mg/Al with different counter-ions and M2+/M3+ ratios were synthesized and used as catalysts in the esterification of fatty acids with methanol. High conversion rates were obtained depending on the reaction conditions. However, LDHs were also converted in situ into layered carboxylates and this new material was responsible for the observed catalytic activity, which was preserved even after several consecutive reuse cycles. .

This paper describes the synthesis and characterization of layered barium, calcium and strontium benzoates and evaluates the potential of these materials as catalysts in the synthesis of methyl benzoate. The methyl esterification of benzoic acid was investigated, where the effects of temperature, alcohol:acid molar ratio and amount of catalyst were evaluated. Ester conversions of 65 to 70% were achieved for all the catalysts under the best reaction conditions. The possibility of recycling these metallic benzoates was also demonstrated, evidenced by unaltered catalytic activity for three consecutive reaction cycles.