Aromatic amination of refined rice bran oil previously epoxidized with Novozym 435

Objective: To synthesize aromatically aminated rice bran oil (APA) using a chemo-enzymatic epoxidation based on Novozym 435 followed by p-xylenediamine insertion. Design/methodology/approach: Refined APA was epoxidized using H2O2/Novozym 435. The resulting epoxidized rice bran oil (eAPA) was functionalized with the aromatic diamine p-xylylenediamine via epoxy ring cleavage (X-eAPA), using ZnCl2 as catalyst. Iodine value (IY), saponification value (IS) and oxirane oxygen content (COO) were determined to evaluate structural changes of the oils. APA, eAPA and X-eAPA were identified using FTIR, 1H and 13C NMR. Results: IY, IS and COO values suggested that the synthesis of eAPA and X-eAPA were effective. The increase in molecular weight in eAPA indicates formation of ~6 epoxy rings per original triglyceride. The COO value of X-eAPA was reduced by 22% compared to that of eAPA, implying that an effective aromatic amination was achieved. FTIR, 1H and 13C NMR spectroscopy studies confirmed the epoxidation and amination of APA. Limitations on study/implications: X-eAPA may be a feasible precursor to obtain high added-value products, as polymers or corrosion inhibitors. Findings/conclusions: Refined rice bran oil partially aromatic aminated was synthesized in two steps, under mild conditions. Epoxidized rice bran oil was obtained using H2O2/Novozym 435, to be immediately functionalized with the aromatic diamine p-xylylenediamine. Keywords: Epoxidation, amination, agro-industrial by-products.Objective: To aromatically aminate refined rice bran oil (RBO), a by-product of the rice agro-industry,through a chemical-enzymatic epoxidation based on Novozym 435 and p-xylylenediamine insertion.Design/Methodology/Approach: Refined RBO was epoxidized with H2O2/Novozym 435. The resultingepoxidized rice bran oil (eRBO) was functionalized with the p-xylylenediamine aromatic diamine via epoxyring-opening (X-eRBO), using ZnCl2 as catalyst. Iodine value (IV), saponification value (SV), and oxiraneoxygen content (OOC) were determined to evaluate structural changes in oils. The RBO, the eRBO, and theX-eRBO were identified using FTIR, 1H, and 13C NMR.Results: The IV, the SV, and the OOC suggest that the synthesis of eRBO and X-eRBO were effective. Theincrease of molecular weight in eRBO point to the formation of 6 epoxy rings per original triglyceride. TheOOC value of X-eRBO was 22% lower than the OOC value of eRBO, implying that an effective aromaticamination was achieved. The FTIR, 1H and 13C NMR spectroscopy analysis confirmed the epoxidation andamination of the RBO.Study Limitations/Implications: X-eRBO may be a feasible precursor for value-added products, such ascrosslinked polymers or corrosion inhibitors.Findings/Conclusions: Refined rice bran oil was aromatically aminated after two stages under mild thermal conditions. This result was achieved with an epoxidation sequence with H2O2/Novozym 435, followed byfunctionalization with p-xylylenediamine

Rice bran oil biorefining: functionalization with acrylate

ABSTRACT Objective: To obtain partially-acrylated refined rice bran oil using a combined H2O2/Novozym 435 epoxidation followed by acrylate group insertion. Design/methodology/approach: Once epoxidized with H2O2/lipase Novozym 435, refined rice bran oil was acrylated via epoxy ring cleavage using triethanolamine as catalyst and 4-methoxyphenol as inhibitor. Conditions for functionalization included temperature (T=100 and 110ºC) and reaction time (t=3 and 4 hours), as well as the ratio g epoxidized oil vs g Acrylic Acid (1.5 and 2.0). To monitor functionalization, we evaluated the iodine value (IY), saponification value (IS), oxygen-oxirane content (COO), as well as FTIR and 1H NMR analysis, thus allowing the %Acrylation to be estimated. Results: 1H NMR studies suggest that the acrylation on rice bran oil was efficient, also confirmed by the evolution of IY, IS and COO values. Using COO, we identified that the best acrylation condition was at T=110ºC, t=3 hours, and g oil vs g Acrylic Acid=1.5, allowing a %Acrylation of 85.89%. Limitations on study/implications: Partially-acrylated rice bran rice oil can become an intermediate product in the biorefining of this oil, and be used in the synthesis of crosslinked polymers. Findings/conclusions: Refined rice bran oil was efficiently acrylated using two consecutive steps, initially H2O2/Novozym 435 epoxidation, followed by functionalization with acrylate group.Objective: To obtain acrylated refined rice bran oil (RBO) using a combined functionalization: first,epoxidation with H2O2/Novozym 435 lipase, followed by acrylate group insertion.Design/Methodology/Approach: After being epoxidized with H2O2/Novozym 435, the refined rice branoil was acrylated via epoxy ring-opening, using triethanolamine as catalyst and 4-methoxyphenol as inhibitor.The experimental conditions of temperature (T=100 and 110 °C) and reaction time (t=3 and 4 hours), as wellas the ratio of g eRBO (epoxidized oil) to g acrylic acid (1.5 and 2.0) were considered for the functionalization.The functionalizations were monitored using iodine value (IV), saponification value (SV), and oxirane oxygencontent (OOC), Fourier transform infrared (FTIR), and nuclear magnetic resonance (1H NMR), which allowedthe estimation of the %Acrylation.Results: The 1H NMR studies indicate that the acrylation of rice bran oil is efficient, which is confirmed withthe evolution of IV, SV, and OOC. Using the OOC, the best acrylation condition was identified at T=110°C, t=3 hours, and ratio of g eRBO to g acrylic acid=1.5, obtaining a %Acrylation of 85.89% via 1H NMR.Study Limitations/Implications: Partially acrylated rice bran oil may become an intermediate in thebiorefining of this oil and be used in the synthesis of crosslinked polymers.Findings/Conclusions: Refined rice bran oil was efficiently acrylated using two consecutive steps: it wasinitially epoxidized with H2O2/Novozym 435, followed by functionalization with acrylate group

Ultrasonic Characterization of Nickel-Chromium-Base Anticorrosive Coatings

One of the most important applications of anticorrosive coatings is the protection of structural components of conventional power generating plants. In particular, nickel- chromium based coatings have been used at the Instituto de Investigaciones Eléctricas in México for their application in boiler tubes and turbine blades of power plants [1]. However, there are not well-established NDE methods to characterize the bonding between the metal base and the coating.</p

Producción de una aleación nanoestructurada FeAL mediante aleación mecánica y su caracterización microestructural

In this work, a Fe40Al alloy was produced by the mechanical alloying technique, from a mixture of elemental powders constituted by Fe and Al, using different milling times. The evolution of size and morphology of powders depending on the milling time was characterized by scanning electron microscopy. The X-Ray Diffraction technique was utilized in order to characterize the crystalline structure evolution depending on the milling time. The Fe40Al alloy with a body centered cubic crystal structure was formed at 20 h of milling time. Besides, this alloy acquired a disordered crystal structure with a Nano metric grain size. The Nano metric grain size of disordered Fe40Al alloy was decreased at the same time as the milling time transcurred, while its lattice parameter was increased.En este trabajo se elaboró la aleación Fe40Al mediante la técnica de aleación mecánica (AM) a partir de una mezcla de polvos elementales de Fe y Al, empleando distintos tiempos de molienda. Se caracterizó la evolución en tamaño y morfología de los polvos empleados en el proceso de AM en función del tiempo de molienda mediante la técnica de Microscopía Electrónica de Barrido (MEB). Se empleó la técnica de Difracción de Rayos X (DRX) para caracterizar la evolución de la estructura cristalina de las fases obtenidas en función del tiempo de molienda. La aleación Fe40Al con estructura cristalina desordenada del tipo cúbico centrado en el cuerpo se formó a las 20 h de molienda. El tamaño nano-métrico de grano correspondiente a la aleación desordenada Fe40Al se redujo con el transcurso del tiempo mientras que su parámetro de red se incrementó con el transcurso del tiempo de molienda

PRODUCTION OF FeAl NANOSTRUCTURED ALLOY BY MECHANICAL ALLOYING AND ITS MICROSTRUCTURAL CHARACTERIZATION

In this work, a Fe40Al alloy was produced by the mechanical alloying technique, from a mixture of elemental powders constituted by Fe and Al, using different milling times. The evolution of size and morphology of powders depending on the milling time was characterized by scanning electron microscopy. The X-Ray Diffraction technique was utilized in order to characterize the crystalline structure evolution depending on the milling time. The Fe40Al alloy with a body centered cubic crystal structure was formed at 20 h of milling time. Besides, this alloy acquired a disordered crystal structure with a Nano metric grain size. The Nano metric grain size of disordered Fe40Al alloy was decreased at the same time as the milling time transcurred, while its lattice parameter was increased

Modelling of Behavior for Inhibition Corrosion of Bronze Using Artificial Neural Network (ANN)

In this work, three models based on Artificial Neural Network (ANN) were developed to describe the behavior for the inhibition corrosion of bronze in 3.5% NaCl + 0.1 M Na2SO4, using the experimental data of Electrochemical Impedance Spectroscopy (EIS). The database was divided into training, validation, and test sets randomly. The parameters process used as the inputs of the ANN models were frequency, temperature, and inhibitor concentration. The outputs for each ANN model and the components in the EIS spectrum (Zre, Zim, and Zmod) were predicted. The transfer functions used for the learning process were the hyperbolic tangent sigmoid in the hidden layer and linear in the output layer, while the Levenberg&ndash;Marquardt algorithm was applied to determine the optimum values of the weights and biases. The statistical analysis of the results revealed that ANN models for Zre, Zim, and Zmod can successfully predict the inhibition corrosion behavior of bronze in different conditions, where what was considered included variability in temperature, frequency, and inhibitor concentration. In addition, these three input parameters were keys to describe the behavior according to a sensitivity analysis

The Synthesis of Aluminum Matrix Composites Reinforced with Fe-Al Intermetallic Compounds by Ball Milling and Consolidation

In this study, a nano-composite material of a nanostructured Al-based matrix reinforced with Fe40Al intermetallic particles was produced by ball milling. During the non-equilibria processing, the powder mixtures with the compositions of Al-XFe40Al (X = 5, 10, and 15 vol. %) were mechanically milled under a low energy regime. The processed Al-XFe40Al powder mixtures were subjected to uniaxial pressing at room temperature. Afterward, the specimens were subjected to a sintering process under an inert atmosphere. In this thermal treatment, the specimens were annealed at 500 °C for 2 h. The sintering process was performed under an argon atmosphere. The crystallite size of the Al decreased as the milling time advanced. This behavior was observed in the three specimens. During the ball milling stage, the powder mixtures composed of Al-XFe40Al did not experience a mechanochemical reaction that could lead to the generation of secondary phases. The crystallite size of the Al displayed a predominant tendency to decrease during the ball milling process. The microstructure of the consolidated specimens indicated a uniform dispersion of the intermetallic reinforcement phases in the Al matrix. Moreover, according to the Vickers microhardness tests, the hardness varied linearly with the increase in the concentration of the Fe40Al intermetallic phase present in the composite material. The presented graphs indicate that the hardness increased almost linearly with the increasing dislocation density and with the reduction in grain sizes (both occurring during the non-equilibria processing). The microstructural and mechanical properties reported in this paper provide the aluminum matrix composite materials with the ideal conditions to be considered candidates for applications in the automotive and aeronautical industries

Corrosion Behavior of Al Modified with Zn in Chloride Solution

Aluminum-based alloys have been considered candidate materials for cathodic protection anodes. However, the Al-based alloys can form a layer of alumina, which is a drawback in a sacrificial anode. The anodes must exhibit uniform corrosion to achieve better performance. Aluminum can be alloyed with Zn to improve their performance. In this sense, in the present research, the electrochemical corrosion performance of Al-xZn alloys (x = 1.5, 3.5, and 5 at.% Zn) exposed to 3.5 wt.% NaCl for 24 h was evaluated. Polarization curves, linear polarization resistance (LPR), and electrochemical impedance spectroscopy (EIS) were used to identify the electrochemical behavior. The microstructure of the samples before the corrosion assessment was characterized by means of X-ray diffraction analyses (XRD) and scanning electron microscopy (SEM). In addition, microstructures of the corroded surfaces were characterized using X-ray mappings via SEM. Polarization curves indicated that Zn additions changed the pseudo-passivation behavior from what pure Al exhibited in a uniform dissolution regime. Furthermore, the addition of Zn shifted the corrosion potential to the active side and increased the corrosion rate. This behavior was consistent with the proportional decrease in polarization resistance (Rp) and charge transfer resistance (Rct) in the EIS. The analysis of EIS was done using a mathematical model related to an adsorption electrochemical mechanism. The adsorption of chloride at the Al-Zn alloy surface formed aluminum chloride intermediates, which controlled the rate of the process. The rate constants of the reactions of a proposed chemical mechanism were evaluated