Hydroxyl Compounds Research Articles

Active visualized solvent sensor based on copolymer hydrogel photonic crystals containing white LEDs

This study demonstrated the achievement of rapid chemical solvent detection by a copolymer hydrogel photonic crystal sensor (CHPCS) created by a simple infiltration of the copolymer hydrogel precursor inside the voids of three-dimensionally opal photonic crystal templates. CHPCS with strong mechanical strength was used as copolymer poly(HEMA-co-MMA-co-NVP) hydrogel and composite poly(St-co-AA-co-MMA) sub-microspheres. CHPCS was immersed in different chemical solvents, including alcohols (hydroxyl compounds) and acetone (carbonyl compounds). The interlayer spacing of CHPCS was swollen and exhibited optical diffraction, which could be detected by the optical measurements and theoretical prediction based on the Bragg diffractive theory. We proposed and demonstrated that CHPCS combined with white LEDs could serve as active naked eye detection solvent sensors that further exhibit great potential as real-time monitoring detectors for chemical solvents.

Optimization of phenol adsorption onto biochar from oil palm empty fruit bunch (EFB)

Malaysia, as one of the leading palm oil producers in the world faces problems in disposal of oil palm empty fruit bunch (EFB), which can be converted into various value-added products, including adsorbents. This study investigated the adsorption of phenol from its solution using biochar produced from EFB through carbonization. Response Surface Methodology (RSM) with Box-Behnken design was used to investigate the effects of three parameters (temperature, time and heating rate) during carbonization on phenol removal by the biochar produced. This was followed by process optimization based on statistical analysis. The results indicated that the optimized carbonization conditions were; 500 °C for temperature, 10 °C/min of heating rate and 80 min for reaction time, which led to 7.57% of phenol removal. SEM revealed coarse and uneven surface of the biochar surface, with small degree of pore development. Comparison between FTIR spectrum of EFB and biochar revealed the loss of water and hydroxyl compounds from EFB during carbonization. The lack of oxygenated groups (especially carbonyl groups) on the adsorbent surface as well as limited number of pores were the possible reasons leading to low phenol adsorption by biochar, therefore conversion of the biochar to activated carbon was necessary for higher adsorption performance.

Recycling and Disposal Methods for Polyurethane Wastes: A Review

Polyurethanes (PU) are a general class of polymers prepared by the polyaddition of isocyanates and hydroxyl group containing compounds. PU foams are formed via the reaction of poly-isocyanate and multi-functional hydroxyl compounds resulting in urethane linkages. The foams are formed in wide range of densities and maybe flexible, semi-flexible or rigid in structure. To control the foam structure, blowing agents are employed. These agents are introduced during foam formation through volatilization of low-boiling liquids or through the formation of gas due to chemical reaction. Additionally, surfactants, catalysts, etc. are used during the manufacturing of foams. PU, including PU foams, is one of the most important groups of materials today and hence, their recycling has been of great interest. Many methods of recycling PU are available and many more are being studied further. However, no method has seen large scale commercialization or is brought into regular practice. The objective of this review is to bring to light the various technologies available and their current status of development as well as newer upcoming methods that may be available in the future.

Influence of the hydrophobic domain on the self-assembly and hydrogen bonding of hydroxy-amphiphiles.

The amphiphiles 1-octadecanol (octadecyl (stearyl) alcohol, ODA) and 1,2-dioleoylglycerol (DOG) were studied by IR spectroscopy and X-ray diffraction combined with multiscale theoretical modeling. The computations allowed us to rationalize the experimental findings and deduce the supramolecular structure of the formed assemblies while providing a fairly detailed insight into their hydrogen-bonding patterns. IR spectra revealed that the amphiphilic assemblies dramatically differ in structural order and hydrogen-bond strength, both being high in ODA and low in DOG. On the other hand, both compounds demonstrated common features, namely a splitting of the IR bands arising from O-H stretching vibrations (νOH) as well as complete hydrophobicity. However, the observed phenomena have different origins in the two amphiphiles. While the νOH split in ODA occurs due to a vibrational coupling along the string of inter-layer O-HO hydrogen bonds, in DOG it arises from different types of hydrogen bonds (intra- and intermolecular). The hydrophobicity of ODA stems from the very tight O-HO hydrogen bonding network connecting the opposite monolayers in a densely packed tilted crystalline phase (Lc'), whereas in DOG it occurs because the polar sites are locked inside reverted micellar-like assemblies. ODA and DOG illustrate that, in the assemblies of amphiphilic hydroxyl compounds, hydrogen bonds can be formed in a wide structural latitude, which is primarily governed by the chemical nature of apolar chains. Such a wide structural variability of OH-involving hydrogen bonds can be essential for the biological functioning of relevant molecules, such as glycolipids, acylglycerols, and, potentially, glycoproteins and carbohydrates.

Fabrication of kW-level chirped and tilted fiber Bragg gratings and filtering of stimulated Raman scattering in high-power CW oscillators

Suppression of stimulated Raman scattering (SRS) by means of chirped and tilted fiber Bragg gratings (CTFBGs) has become a key topic. However, research on high-power systems is still lacking due to two problems. Firstly, after the inscription, there are a large number of hydroxyl compounds and hydrogen molecules in CTFBGs that cause significant heating due to their strong infrared absorption. Secondly, CTFBGs can couple Stokes light from the core to the cladding and the coating, which causes serious heating in the coating of the CTFBG. Aimed at overcoming these bottlenecks, a process that combines constant-low-temperature and variable-high-temperature annealing is used to reduce the thermal slope of the CTFBG. Also, a segmented-corrosion cladding power stripping technology is used on the CTFBG to remove the Stokes light which is coupled to the cladding, which solves the problem of overheating in the coating of the CTFBG. Thereby, a CTFBG with both a kilowatt-level power-carrying load and the ability to suppress SRS in a fiber laser has been developed. Further, we establish a kW-level CW oscillator to test the CTFBG. Experimental results demonstrate that the power-carrying load of the CTFBG is close to 1 kW, the thermal slope is lower than $0.015\,^{\circ }\text{C}/\text{W}$, and the SRS suppression ratio is nearly 23 dB.

Stepwise degradation of hydroxyl compounds to aldehydes via successive C-C bond cleavage.

Stepwise degradation of hydroxyl compounds to aldehydes via successive cleavage of C-C bonds was achieved by using a bimetallic catalytic system (PdCl2 + CuCl) without any ligands and additives. The broad applicability is expanded to a diverse range of aromatic, aliphatic, primary and secondary alcohols, as well as lignin model compounds.

Adsorption Properties and Mechanism of Cd2+ in Water by Zr-containing Silica Residue Purification.

Zirconium (Zr)-containing silica residue purification (ZSR-P) discharged from industrial production of ZrOCl2 was used as an adsorbent, and CdCl2 solution was used as the simulated wastewater containing cadmium ions (Cd2+). The properties and mechanisms of ZSR-P absorbing Cd2+ were studied. The results showed that ZSR-P had a good effect on the adsorption and removal of Cd2+ in water. The adsorption time, initial concentration of Cd2+, and pH of the solution had a significant effect on the adsorption behavior, whilst the pH value had the greatest effect amongst them. Under optimal conditions, the amount of Cd2+ adsorbed by ZSR-P was 43.1 mg/g. The isothermal adsorption conformed to the Langmuir adsorption model, and the adsorption kinetics conformed to the secondary adsorption rate model. In ZSR-P-Cd, Cd2+ was uniformly distributed on the surface of SiO2 particles and in the pores formed by the accumulation of particles. Adsorption of Cd2+ by ZSR-P was achieved through the reaction between Si-OH on the surface of SiO2 and Cd2+ hydroxyl compounds.

Facile synthesis of novel disperse azo dyes with aromatic hydroxyl group

A series of novel disperse azo dyes containing aromatic hydroxyl group were synthesized by a novel and simple synthetic strategy, in which, the stable solid diazonium salts of weakly basic amines were used to couple with aromatic hydroxyl compounds in alkaline aqueous solution. The experimental procedure was simple and had a high reaction rate and excellent yields. The structures of the dyes were confirmed by HRMS, FT-IR, 1H NMR, and elemental analysis. Then, the synthesized azo dyes were used for dyeing polyester fabric and gave favorable color fastness that was comparable with that of commercial dyes.

Autoclave-assisted green synthesis of silver nanoparticles using A. fumigatus mycelia extract and the evaluation of their physico-chemical properties and antibacterial activity

AbstractSilver nanoparticles (AgNPs) were synthesized usingAspergillus fumigatus(A. fumigatus) mycelia extract via the hydrothermal method. The main reducing and stabilizing groups and components ofA. fumigatusextract, such as amine, hydroxyl, amid, protein, enzymes, and cell saccharide compounds, were identified by Fourier transform infrared (FT-IR). Central composition design was used to plan the experiments, and response surface methodology was applied to evaluate of the effects of independent variables, including the amount of the prepared extract (5–7 ml) and heating time (10–20 min) at 121°C and 1.5 bar), on the particle size of the synthesized AgNPs, as manifested in broad emission peak (λmax). More stable and spherical monodispersed AgNPs, with mean particle size, polydispersity index (PDI) value, and maximum ζ potential value of 23 nm, 0.270, and +35.3 mV, respectively, were obtained at the optimal synthesis conditions using 7 ml ofA. fumigatusextract and heating time of 20 min. The synthesized AgNPs indicated high antibacterial activity against both Gram-positive and Gram-negative bacteria.

Adsorption Mechanism of Pb2+ Activator for the Flotation of Rutile

In general, the flotation of minerals containing titanium needs to be activated by metal ions due to a lack of activating sites on their surface. However, the activating process is indirectly inferred due to the lack of direct experimental observation. In this study, atomic force microscopy (AFM) was used to observe the activation process. The results revealed that the hydroxyl compounds of Pb2+ ions were adsorbed on the rutile surface in the form of multiple molecular associates, rather than through single molecule adsorption. Styryl phosphoric acid (SPA) could largely be adsorbed on the activated rutile surface with a single and double layer rather than on the un-activated rutile surface. The results of contact angle measurements also revealed that the hydrophobicity of the activated rutile surface was significantly greater than that of the un-activated rutile surface after SPA was adsorbed. This study will be helpful to understanding the activating process from the microscale.

Applications of bio-oil-based emulsions in a DI diesel engine: The effects of bio-oil compositions on engine performance and emissions

Biomass-derived bio-oil cannot be applied directly in diesel engines due to several poor fuel properties such high viscosity and instability. Emulsification could overcome the disadvantages of bio-oil. In this study, bio-oil emulsified with diesel was combusted in a DI diesel engine, and the effects of bio-oil compositions on the engine performance and emissions were investigated. Crude bio-oil has aging and instability problems, which could cause inconsistencies in the results. Synthetic bio-oil was used to avoid the limitations posed by crude bio-oil. Synthetic bio-oil was fractioned into three categories (hydroxyl compounds, aldehydes and sugars), and the corresponding emulsions were prepared. Compared with diesel, the brake-specific fuel consumption (BSFC) and brake-specific energy consumption (BSEC) were increased, and the brake power remained almost unchanged for the emulsions. For the exhaust emissions, CO and smoke emissions were decreased, while CO2 emissions were increased. The emulsions derived from the aldehydes and hydroxyl compounds reduced NOx emissions, whereas emulsions derived from sugars and the whole bio-oil increased NOx emissions. The results indicated that the aldehydes and hydroxyl compounds in bio-oil were more desirable for clean combustion than sugars. The hydroxyl compounds could result in the largest emissions reductions due to the presence of OH radicals.

Laser Modified Phenothiazines and Hydantoins: Photo-products Characterisation and Application on Animal Eyes Pseudo-tumours

Background: The use of laser methods to irradiate currently used drugs in order to obtain photo-products with antimicrobial and anti-tumour activity constitutes a new approach in fighting antimicrobial resistance acquired by bacteria and tumours. Methods: The interaction of UV laser radiation with phenothiazine derivatives, such as chlorpromazine, thioridazine and promethazine, and a hydantoin derivative, SZ-2, was evaluated using analytical techniques: UV-Vis-NIR absorption, FTIR, and laser induced florescence. Results: The investigation of photo-products mixtures suggested the photo-generation of sulfoxide and hydroxyl compounds when phenothiazine derivatives were irradiated and the braking of molecule and detachment of radical attached to thio-hydantoin ring when SZ-2 was irradiated. As for application of laser irradiated drug solutions on pseudo-tumours induced in rabbit eyes using Schmidt-Erfurth method, it was observed a decrease of inflammations related to pseudo-tumours and a fast recovery of corneal tissues. Conclusion: The best effect concerning the recuperation of healthy corneal tissue quality in the pseudo-tumour was observed for 10 mg/mL chlorpromazine irradiated 20 min with 266 nm laser beam. This new method offers the possibility to combat antimicrobial resistance acquired by tumours or bacteria by flexible development of new agents using laser systems and techniques. Keywords: Corneal tissue, eye pseudotumour, hydantion, laser induced fluorescence, laser irradiation, multiple drug resistance, phenothiazines, SZ-2, photo-degradation.

Application of Multiple Regression and Design of Experiments for Modelling the Effect of Monoethylene Glycol in the Calcium Carbonate Scaling Process.

To avoid gas hydrate formation during oil and gas production, companies usually employ thermodynamic inhibitors consisting of hydroxyl compounds, such as monoethylene glycol (MEG). However, these inhibitors may cause other types of fouling during production such as inorganic salt deposits (scale). Calcium carbonate is one of the main scaling salts and is a great concern, especially for the new pre-salt wells being explored in Brazil. Hence, it is important to understand how using inhibitors to control gas hydrate formation may be interacting with the scale formation process. Multiple regression and design of experiments were used to mathematically model the calcium carbonate scaling process and its evolution in the presence of MEG. It was seen that MEG, although inducing the precipitation by increasing the supersaturation ratio, actually works as a scale inhibitor for calcium carbonate in concentrations over 40%. This effect was not due to changes in the viscosity, as suggested in the literature, but possibly to the binding of MEG to the CaCO3 particles’ surface. The interaction of the MEG inhibition effect with the system’s variables was also assessed, when temperature’ and calcium concentration were more relevant.

Role of chemical functional groups on thermal and electrical properties of various graphene oxide derivatives: a comparative x-ray photoelectron spectroscopy analysis

In recent years, graphene and its derivatives have become prominent subject matter due to their fascinating combination of properties and potential applications in a number application. While several fundamental studies have been progressed, there is a particular need to understand how different graphene derivatives are influenced in terms of their electrical and thermal conductivities by different functional groups they end up with through their manufacturing and functionalisation methods. This article addresses of the role of different functional groups present of different of reduced graphene oxides (rGO) concerning their electrical and thermal properties, and the results were compared with elemental analyses of functionalised reduced graphene oxide (frGO) and graphene. The results showed that electrical and thermal conductivities of the rGO samples, highly dependent on the presence of residual functional groups from oxidation, reduction and functionalisation processes. The increase in reduction of oxygen, hydroxyl, carboxylic, epoxide moieties and heterocyclic compounds increase the specific surface area of the samples through which the mean electron path has increased. This improved both electrical and thermal conductivities together in all the samples which were highly dependent on the efficiency of different reductant used in this study.

OXIDATION OF PROPANE-BUTANE MIXTURE IN DIELECTRIC BARRIER DISCHARGE IN PRESENCE OF LIQUID OCTANE

The results of oxidation of a propane-butane mixture in a barrier discharge plasma in the presence of liquid octane are presented. The conversion of the gas-liquid mixture results in the formation of an oxygenate containing predominantly hydroxyl and carbonyl compounds with the same number of carbon atoms in a molecule as in the starting compounds. The presence of a liquid octane film flowing down the plasma-chemical reactor walls enables an effective removal of the reaction products from the discharge zone due to dissolution of the compounds formed therein. Alkyl radicals, atomic oxygen, and hydrogen are the main active particles. The formation of both oxygenated compounds and hydrocarbons with isomeric structure occurs as a result of their further chemical transformations. The mechanism of conversion of gaseous hydrocarbons is much like that for the conversion of liquid hydrocarbons in a barrier discharge plasma. They both are carried out under similar conditions. The change in the initial concentration of the propane-butane mixture in the gas phase from 10 to 75 % wt results in a decrease in the conversion of gaseous hydrocarbons from 4.1 to 0.9 % wt, while the conversion of octane decreases from 2.4 to 0.3% wt. in one pass through the reactor. The decrease in hydrocarbon conversion is due to decrease in the rate of formation of atomic oxygen in a discharge gap of the reactor. Theoretical calculations were performed using the software package Bolsig+ for the model oxygen-propane mixture. The results of calculations show that the rate constant of oxygen dissociation increases from 1.87·10-10 cm3/s to 6.71·10-9 cm3/s, due to an increase in the average electron energy from 3.4 to 4.1 eV. It was found out that the mass of products formed in result of oxidation of gaseous and liquid hydrocarbons depends on the initial concentration of the starting compounds in the vapor-gas mixture. A simple expression is proposed that allows one to evaluate the preferential direction of the plasma-chemical reaction as a function of the initial concentration of hydrocarbons in a discharge gap of the reactor.Forcitation:Kudryashov S.V., Ryabov A.Yu., Ocheredko A.N. Oxidation of propane-butane mixture in dielectric barrier discharge in presence of liquid octane. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 3. P. 88-92

Fatty acidomics: Evaluation of the effects of thermal treatments on commercial mussels through an extended characterization of their free fatty acids by liquid chromatography – Fourier transform mass spectrometry

An unprecedented characterization of free fatty acids (FFA) in the lipid extracts of fresh or thermally treated mussels of sp. Mytilus galloprovincialis, including up to 128 saturated, mono- or poly-unsaturated and 63 oxidized (i.e., modified by hydroxylic, carbonylic and/or epoxylic groups) compounds, was achieved using reverse phase chromatography coupled to electrospray ionization-Fourier transform single and tandem mass spectrometry (RPC-ESI-FTMS,MS/MS). Subsequent Principal Components Analysis (PCA) evidenced several effects of thermal treatments on the mussel FFA profiles. In particular, death-inducing low temperature treatments (freezing at −16 °C or refrigeration at 4 °C for several days) induced a peculiar increase in the incidence of FFA, whereas the effect was absent in mussels undergoing death upon prolonged storage at room temperature (25 °C, 6 h) or fast cooking (100 °C, 5 min). Alive mussels, either fresh or resulting from short term (up to 48 h) refrigeration were actually indistinguishable by PCA, although subtle seasonal effects were observed.

Inhibitory effect of pyrogallol on α-glucosidase: Integrating docking simulations with inhibition kinetics

In this study we conducted serial kinetic studies integrated with computational simulations to judge the inhibitory effect of pyrogallol on α-glucosidase, due to the association between this enzyme and the treatment of type 2 diabetes. As a result, we found that pyrogallol bound to the active site of α-glucosidase, interacting with several key residues, such as ASP68, MET69, TYR71, PHE157, PHE158, PHE177, GLN181, HIS348, ASP349, ASP406, VAL407, ASP408, ARG439, and ARG443, which was predicted by performing a protein-ligand docking simulation. Subsequently, we evaluated the inhibitory effect of pyrogallol on α-glucosidase, and found that it induced a mixed type of inhibition in a reversible and quick-binding manner. The relevant kinetic parameters were evaluated to be: IC50=0.72±0.051mM; Ki=0.37±0.018mM. A tertiary conformational change was synchronized with pyrogallol inhibition and modulation of the shape of the active site was correspondingly observed. Our study provides insight into the functional inhibitory role of pyrogallol, which results from its triple-hydroxyl groups interacting with the active site of α-glucosidase. We suggest that compounds similar to pyrogallol (phenolic hydroxyl compounds) which target the key residues of the active site of α-glucosidase could be potential agents for α-glucosidase inhibition.

Definition of synthesis parameters of ultrafine nickel powder by direct electrolysis for application in superalloy production

The optimization of the synthesis method of ultrafine nickel powder for the production of superalloys, by means of direct electrolysis of the nickel ammine complex, has been conducted. The influence of electrolyte temperature and ammonia concentration on the electrolysis process and powder characteristics has been studied. It has been revealed that an increase in electrolyte temperature leads to a larger particle size of the powder and formation of compact metal particles. It has been determined that the maximum electrolyte temperature must not exceed 50 °С. By recording the polarization curves, it was established that an increase in ammonia concentration leads to increased polarization of nickel formation and formation of finer powder. Lowering of ammonia concentration leads to contamination of the powder with barely soluble hydroxyl compounds of nickel. Analysis of the anodic curves has revealed that the nickel anode is partly soluble. It has been discovered that the addition of Trilon B to the electrolyte has a positive effect on powder characteristics. The powder formed under optimal conditions was composed of coral-like particles with the size of 40–70 µm, which could be easily ground to their spherical components if no compact metal particles were present. High purity of the powder was confirmed by the EDX. The cathodic and anodic current yields were determined to be: 35–41 % and 5–8 % respectively.

Design and synthesis of novel dasatinib derivatives as inhibitors of leukemia stem cells

We used the concept of bioisosteres to design and synthesize a novel series of dasatinib derivatives for the treatment of leukemia. Unfortunately, most of the dasatinib derivatives did not show appreciable inhibition against leukemia cell lines K562 and HL60. However, acrylamide compound 2c had comparable inhibitory activity with dasatinib against K562 cells (IC50 = 0.039 nM vs. 0.069 nM). And amide compound 2a and acrylamide compound 2c also had comparable inhibitory activity with dasatinib against the leukemia cell line HL60 (IC50 = 0.25 nM and 0.26 nM vs. 0.11 nM). Against the leukemia progenitor cell line KG1a, triazole compounds 15a and 15d–15f and oxadiazole compounds 24a–24d were more potent than dasatinib. In particular, the hydroxyl compounds 15a and 24a were about 64 and 180 fold more potent than dasatinib against KG1a cells (IC50 = 0.14 μM and 0.05 μM vs. 8.98 μM). Compounds 15a and 24a also inhibited colony formation in MCF-7 cells and inhibited cell migration in the cell wound scratch assay in B16BL6 cells. Moreover, hydroxyl compounds 15a and 24a had low toxicity in vivo.

Understanding and Measurement for the Binding Energy of Hydrogen bonds of Biomass-Derived Hydroxyl Compounds.

Experimental measurement for the binding energy of hydrogen-bonds (HBs) has long been an attractive and challenging topic in chemistry and biochemistry. In the present study, the binding energy of OH···O HBs can be determined by 1H NMR technique using a set of model biomass-derived hydroxyl compounds, including furfuryl alcohol, isosorbide, tetrahydrofurfuryl alcohol, and (S)-3-hydroxytetrahydrofuran. By performing concentration- and temperature-variation experiments, we put forward a modified Arrhenius-type equation, in which the compensated natural logarithm of the chemical shift (ln δ + Δδ) is linearly correlated with 1/T. HBs energies can be directly determined by the slope of the plot, and are substantiated by density functional theory (DFT) theoretical calculations. This study provides a reliable method to measure the binding energy of OH···O HBs in hydroxyl-containing biomass-derived feedstocks.