Presence Of Isopropanol Research Articles

ENANTIOSELECTIVE SYNTHESIS OF (S)-(-)-1-(4-FLUOROPHENYL)ETHANOL

S)-(–)-1-(4-Fluorophenyl)ethanolis an intermediate in the synthesis of an antagonist of the CCR5 chemokine receptor that can be protective against HIV infection. Along with o-fluoro-substituted analogs, (S)-(–)-1-(4-fluorophenyl)ethanol can be used to study the role of substituents in the chiral recognition of molecular complexes, and (R)-(+)-1-(4-fluorophenyl)ethanol is a com-ponent of an antimalarial drug and a γ-secretase modulator necessary for the treatment of Alzhei-mer's disease.We proposed an approach to the synthesis of (S)-(-)-1-(4-fluorophenyl)ethanol based on the enantioselective reduction of prochiral 1-(4-fluorophenyl)ethanone catalyzed by Daucus carota cells. We found the conditions that make it possible to obtain (S)-(–)-1-(4-fluorophenyl)eth-anol by bioreduction of 1-(4-fluorophenyl)ethanone in the presence of a D. carota biocatalyst for 48 h with 55% yield (98% ee).We also studied the possibility of optimizing the transformation of 1-(4-fluorophenyl)ethanone in a reaction medium containing various exogenous reducing agents(ethanol, isopropanol, or glucose), which are known to significantly affect the product yield and the enantioselectivity of the process. Biotransformation of 1-(4-fluorophenyl)ethanone in the pres-ence of ethanol (1-5%) gives (S)-(-)-1-(4-fluorophenyl)ethanol with 7-85% yields and optical purity 10-98% ee.Enantioselective reduction of the initial ketone in the presence of isopropanol (1-5%) does not lead to a significant increase in the yield and optical purity of S-alcohol (7-57% (18-98% ee).In the case of biotransformation of 1-(4-fluorophenyl)ethanone in the presence of an equimo-lar amount of glucosefor 48 hthe yield of (S)-(-)-1-(4-fluorophenyl)ethanol is 66% (98% ee).Fur-ther transformation of the initial ketone (144 h) both in the absence of an exogenous reducing agent and in the presence of an equimolar amount of glucose leads to an increase in the yield of alcohol to 73% and 76%, respectively, however, the optical purity of the alcohol decreases to 62% ee and 80% ee, which suggests the stereoinversion.

Facile Post-Carboxymethylation of Cellulose Nanofiber Surfaces for Enhanced Water Dispersibility.

To improve the water dispersibility of cellulose nanofibers without deteriorating the physical properties, it is necessary to develop methods that can selectively modify fiber surfaces. Herein, the reaction conditions for carboxymethylation of the surface of nanofibrillated bacterial cellulose were optimized using chloroacetic acid as an etherification agent. Carboxymethylation in a high-concentration alkaline solution (>5 wt %) in the presence of isopropanol caused the mercerization and carboxymethylation of not only the nanofiber surface but also the cellulose crystals within the nanofiber, resulting in nanofiber swelling and an increase in fiber width. In contrast, with a dilute alkaline aqueous solution (3 wt %), the nanofiber surface was successfully carboxymethylated without changing the inner structure. Furthermore, the morphology was not affected by the carboxymethylation reaction, and no fiber swelling occurred under these reaction conditions. When the substitution reaction proceeded only on the nanofiber surface, the maximum degree of substitution (i.e., the average number of carboxymethyl groups substituted per anhydroglucose residue in cellulose) was 0.091. After surface modification, the nanofibers became more negatively charged, which improved the dispersibility in water through electrostatic repulsion, resulting in a drastic increase in the transparency of the nanofiber dispersion. This method provides a general approach for the surface modification of cellulose nanofibers to increase water dispersibility.

Dentin interaction with universal adhesive containing isopropanol solvent studied by solid-state NMR spectroscopy

ObjectiveThis study investigated the chemical and structural changes in the mineral phase and collagen of dentin during application of a mild universal adhesive. Particular attention was paid to the role of isopropanol and changes in water molecules. MethodsIn vitro application of the mild universal adhesive on dentin with two established etching modes (self-etch and etch-and-rinse) was studied using solid state nuclear magnetic resonance spectroscopy. ResultsIt was evidenced that the etch-and-rinse mode leads to a decrease of the inorganic apatite and a reorganization of the residual mineral phase with a low amount of adhesive phosphate monoesters calcium salt formed, compared to the self-etch mode. In contrast, the adhesive interacts very similarly to the level of dentin collagen in both protocols, with a strong decrease in the amount of the free water molecules induced by the presence of isopropanol as the adhesive solvent, but without significant changes in the initial collagen structure. For both modes, the adhesive acrylates monomers remain mobile and can infiltrate the collagen. SignificanceUnderstanding the molecular interactions between dentin and adhesive solutions is a major challenge for designing products that lead to the formation of ideal dentin resin hybrid layer. Notably, one point considered essential is the presence of unbound water which, over time, is associated with a hydrolytic degradation of the organic matrix. Isopropanol, as an adhesive solvent, leads to a decrease in the amount of the less stable water molecules while the water molecules strongly attached to the collagen are retained, thus preserving the collagen structure.

In Vitro Fish Models for the Analysis of Ecotoxins and Temperature Increase in the Context of Global Warming.

Rising temperatures can affect fish survival, especially from shallower waters, as temperatures increase faster and more intensively in these areas; thus, species-specific temperature tolerance can be exceeded. Additionally, the amounts of anthropogenic pollutants are higher in coastal waters. Although increasing metabolic activity at higher temperatures could lead to stronger effects of toxins, there are hardly any studies on this topic. Subsequently, the aim was to investigate the response of fish cells upon exposure to industrial solvents (ethanol, isopropanol, dimethyl sulfoxide (DMSO)) in relation to a temperature increase (20 °C and 25 °C). Concerning the 3Rs (the replacement, reduction and refinement of animal experiments), in vitro tests were used for two threatened, vulnerable fish species: maraena whitefish (Coregonus maraena) and Atlantic sturgeon (Acipenser oxyrinchus). Both cell lines exhibited higher proliferation at 25 °C. However, ecotoxicological results indicated significant differences regarding the cell line, toxin, temperature and exposure time. The evolutionarily older fish lineage, Atlantic sturgeon, demonstrated lower mortality rates in the presence of isopropanol and recovered better during long-term ethanol exposure than the maraena whitefish. Atlantic sturgeon cells have higher adaptation potential for these alcohols. In summary, fish species respond very specifically to toxins and changes in temperature, and new ecotoxicological questions arise with increasing water temperatures.

Mechanistic Investigations on the Catalytic Transfer Hydrogenation of Lignin-Derived Monomers over Ru Catalysts: Theoretical and Kinetic Studies

The hydrodeoxygenation (HDO) reaction of oxygenated compounds such as lignin-derived phenolics is well studied using molecular H2 as a hydrogen source, yet the use of high pressures discourages its use on an industrial scale. As an alternative, the catalytic transfer hydrogenation (CTH) pathway provides in situ hydrogenation species, which reduces the need for the high-pressure infrastructure required when molecular hydrogen is used. Nevertheless, this strategy is scantly studied, and in lieu with this, herein we report the kinetic and mechanistic investigations of the CTH strategy for the HDO of guaiacol, phenol, anisole veratrole, and eugenol to their respective products. For potential commercialization purposes, low loading of metal, milder reaction conditions, and high selectivity toward desired products with a high H/C ratio were considered while designing catalysts (0.5 wt % Ru on SiO2–Al2O3, SiO2, Al2O3-acidic, Al2O3-basic, and Al2O3-neutral) for these reactions. As high as 74% cyclohexanol yield from guaiacol was achieved at 225 °C in the presence of isopropyl alcohol (IPA) as the hydrogen source and over the Ru/Al2O3-acidic catalyst reduced at 150 °C. A detailed kinetic study is carried out to understand the interaction of the substrate and intermediates with the catalyst and the influence of reaction parameters on the product formation. It was observed that the cis-isomer of 2-methoxycyclohexanol rapidly undergoes further conversion than the trans-isomer. The experimental observations are substantiated through density functional theory (DFT) studies on Ru(0001) and guaiacol molecule complexes. DFT studies indicate that the adsorption of the cis-isomer is more exothermic as compared to that of the trans counterpart, and the underlying electronic factors are elucidated using charge density difference and density of states plots.

Comparison of naphthalene removal performance using H2O2, sodium percarbonate and calcium peroxide oxidants activated by ferrous ions and degradation mechanism

The presence of polycyclic aromatic hydrocarbons (PAHs) in groundwater is making a great threat to human health in the world which has received an increasing environmental concern. Among various Fenton oxidation processes, 97.6%, 92.1% and 89.4% naphthalene (NaP) removals were observed using hydrogen peroxide (H2O2), sodium percarbonate (SPC) and calcium peroxide (CP) as oxidants activated by Fe(II) in ultrapure water tests, respectively. While, the inhibitory effect on NaP degradation caused by the weak alkaline solution pH and the presence of HCO3− in actual groundwater could be compensated by doubling dosages of oxidants and Fe(II) to different extent. 98.0%, 49.8% and 11.5% of NaP were degraded by using H2O2, SPC and CP, respectively, strongly suggesting the best H2O2 performance among them. It was observed that 83.3% and 9.6% inhibition on NaP degradation in H2O2/Fe(II)/NaP system occurred in the presence of isopropyl alcohol and chloroform, confirming that both hydroxyl radical (HO) and superoxide anion radical (▪) contributed to NaP degradation in Fenton process and HO was the prominent radical. The presence of HO was further demonstrated by electro-spin resonance spectrometer analysis. The identification of transformation products of NaP revealed that hydroxylation and ring rupture were the main NaP degradation pathways.

Visible light-induced photocatalytic and antibacterial activity of TiO2/polyaniline-kapok fiber nanocomposite

Anatase TiO2 nanoparticles with an average crystallite size of around 6.06 nm were successfully immobilized on the surface of polyaniline-coated kapok fiber (PANI-KpF) via hydrothermal reaction. The photocatalytic activity of the TiO2/PANI-KpF nanocomposite was studied under visible light using methyl orange (MO) and Cr(VI) as model pollutants. Photodegradation of MO was achieved using nanocomposites prepared with 0.5 and 1.0 mL titanium isopropoxide (TTIP) with removal efficiencies of about 87.4 and 76.8%, respectively. These are about 13 and 18% higher than the removal efficiencies under dark conditions. On the other hand, visible light-induced photo-reduction of Cr(VI) was carried out in the presence of isopropanol (IPA) as a hole scavenger, with 100% removal efficiency. Without IPA, Cr(VI) was removed by adsorption. The TiO2/PANI-KpF also showed antibacterial activity against E. coli bacteria under visible light.

Electrocatalytic oxidation of 2-propanol on PtxIr100-x bifunctional electrocatalysts – A thin-film materials library study

Due to the high demand for renewable and infrastructure compatible energy conversion and storage technologies, research on organic fuel cells receives increasing interest again recently. Organic fuels such as alcohols provide an attractive avenue to overcome the drawbacks of hydrogen as an energy carrier. Particularly interesting are secondary alcohols that almost exclusively form ketones as the final oxidation product, as they can be utilized in “zero emission” concepts without CO2 as a by-product. The state-of-the-art electrocatalyst in secondary alcohol oxidation is Pt-Ru, which demonstrates low onset potentials for the oxidation of the most facile secondary alcohol isopropanol. Yet, the achievable current densities are still relatively low and decrease rapidly due to the formed product acetone, which can poison the catalyst surface over time. Therefore, there is an inevitable need for the development of novel electrocatalyst materials circumventing these challenges. In this study, we employ a high-throughput electrochemical approach coupled to on-line inductively-coupled plasma mass spectrometry to map the composition-dependent activity and stability of PtxIr100-x alloy electrocatalysts toward the electro-oxidation of isopropanol. The activity and stability of magnetron sputtered PtxIr100-x material libraries are studied in 0.1 M HClO4 both in the absence and presence of isopropanol. The highest current densities are achieved for the sample containing the least amount of Ir (3.4 at.%), with a continuous decrease with the increasing amount of Ir. The alloys are inactive towards the oxidation of isopropanol when the amount of Ir exceeded 80 at%. The presence of isopropanol also has a notable effect on stability: while dissolution rates do not change in the case of pure Pt and Ir, a significant increase in stability is observed for the PtxIr100-x thin-film samples at all applied upper potential limits. This is explained by the strong adsorption of acetone on the surface of the catalyst that inhibits the formation of surface oxides.

Ferroelectric, dielectric, magnetic, structural and photocatalytic properties of Co and Fe doped LaCrO3 perovskite synthesized via micro-emulsion route

In the present investigation, La1-xCoxCr1-yFeyO3 (x,y = 0.0, 0.12, 0.36, 0.60) perovskite was fabricated via a facile micro-emulsion route. The synthesized perovskites were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) techniques to examine the effect of Co and Fe ions on the physico-chemical properties. The ferroelectric, dielectric, and magnetic properties of La1-xCoxCr1-yFeyO3 were changed significantly as a function of dopants contents (Co and Fe ions). Outcomes revealed that the dielectric, ferroelectric and magnetic properties of LaCrO3 perovskite can be tuned significantly via Co and Fe doping and La0.40Co0.60Cr0.40Fe0.60O3 have potential for photocatalytic dye removal under (visible) light expoure. The photocatalytic activity (PCA) of the pristine LaCrO3 and La0.40Co0.60Cr0.40Fe0.60O3 photocatalyst was evaluated under (visible) light irradiation for crystal violet (CV) dye. Experimental results revealed that La0.40Co0.60Cr0.40Fe0.60O3 photocatalyst degrdae almost 77.21% CV dye with the rate constant value of 0.01475 min−1. In the presence of isopropyl alcohol (IPA) scavenger, the PCA of the La0.40Co0.60Cr0.40Fe0.60O3 photocatalyst and rate constant value of the photocatalytic reaction decreased to 32.5% and 0.00491 min−1, suggesting the superoxide as main active specie. Results revealed that Co and Fe doping doped material is efficient for photocatalytic presentations under solar light expoure.

Influence of the Substrate, Process Conditions, and Postannealing Temperature on the Properties of ZnO Thin Films Grown by the Successive Ionic Layer Adsorption and Reaction Method.

Here, we report the effect of the substrate, sonication process, and postannealing on the structural, morphological, and optical properties of ZnO thin films grown in the presence of isopropyl alcohol (IPA) at temperature 30–65 °C by the successive ionic layer adsorption and reaction (SILAR) method on both soda lime glass (SLG) and Cu foil. The X-ray diffraction (XRD) patterns confirmed the preferential growth thin films along (002) and (101) planes of the wurtzite ZnO structure when deposited on SLG and Cu foil substrates, respectively. Both XRD and Raman spectra confirmed the ZnO and Cu-oxide phases of the deposited films. The scanning electron microscopy image of the deposited films shows compact and uniformly distributed grains for samples grown without sonication while using IPA at temperatures 50 and 65 °C. The postannealing treatment improves the crystallinity of the films, further evident by XRD and transmission and reflection results. The estimated optical band gaps are in the range of 3.37–3.48 eV for the as-grown samples. Our experimental results revealed that high-quality ZnO thin films could be grown without sonication using an IPA dispersant at 50 °C, which is much lower than the reported results using the SILAR method. This study suggests that in the presence of IPA, the SLG substrate results in better c-axis-oriented ZnO thin films than that of deionized water, ethylene glycol, and propylene glycol at the optimum temperature of 50 °C. Air annealing of the samples grown on Cu foils induced the formation of CuxO/ZnO junctions, which is evident from the characteristic I–V curve including the structural and optical data.

Kinetic studies on esterification of acetic acid with isopropyl alcohol in presence of novel solid catalyst

Abstract The reaction of isopropyl alcohol with acetic acid was carried out in an isothermal batch reactor in presence of solid resin catalyst to produce isopropyl acetate and water. A novel solid resin catalyst Indion 140 was used in the present study. The temperature of reaction mixture was maintained in the range of 333.15 – 363.15 K. The effects of reaction temperature, catalyst loading, mole ratio, size of catalyst, agitation speed were investigated on acetic acid conversion. Further, pseudo-homogeneous kinetic model was developed for the catalyzed reaction. The forward reaction rate constants and activation energies were determined from the Arrhenius plot. The forward and backward activation energies are found to 53,459 J/mol and 54,748 J/mol, respectively. The heat of reaction is −1.289 kJ/mol with Indion 140 catalyst. The mathematical equation was developed for frequency factor as function of the catalyst loading and found that it follows a linear relationship between frequency factor and catalyst loading. The simulations were performed for pseudo homogeneous kinetic model and found that the model is able to predict the experimental data very well. The developed kinetic equation is useful for the simulation of a reactive distillation column for the synthesis of isopropyl acetate.

Sonophotocatalytic Degradation of Malachite Green by Nanocrystalline Chitosan-Ascorbic Acid@NiFe2O4 Spinel Ferrite

Statistics show that more than 700 thousand tons of dye are produced annually across the globe. Around 10–20% of this is used in industrial processes such as printing and dyeing, while about 50% of the dye produced is discharged into the environment without proper physicochemical treatment. Even trace amounts of dye in water can reduce oxygen solubility and have carcinogenic, mutagenic, and toxic effects on aquatic organisms. Therefore, before dye-containing wastewater is discharged into the environment, it must be properly treated. The present study investigates the green synthesis of nickel ferrite NiFe2O4 (NIFE) spinel magnetic nanoparticles (MNPs) via chemical coprecipitation of a solution of Ni2+/Fe3+ in the presence of a biopolymer blend of chitosan (CT) and ascorbic acid (AS). The magnetic nanomaterial was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy–energy dispersive X-ray analysis (SEM-EDX), transmission electron microscopy (TEM), ultraviolet-visible spectroscopy (UV-Vis), differential scanning calorimetry (DSC), and vibrating-sample magnetometry (VSM). The material was further explored as a catalyst for the photocatalytic degradation of malachite green (MG) under visible light irradiation coupled with ultrasonic waves. The combination of 90 min of visible solar light irradiation with 6.35 W·mL−1 ultrasonic power at pH 8 resulted in 99% of the photocatalytic efficiency of chitosan-ascorbic acid@NIFE (CTAS@NIFE) catalyst for 70 mg·L−1 MG. The quenching of the photocatalytic efficiency from 98% to 64% in the presence of isopropyl alcohol (IPA) suggested the involvement of hydroxy (•OH) radicals in the mineralization process of MG. The high regression coefficients (R2) of 0.99 for 35, 55, and 70 mg·L−1 MG indicated the sonophotocatalysis of MG by CTAS@NIFE was best defined by a pseudo first-order kinetic model. The mechanism involves the adsorption of MG on the catalyst surface in the first step and thereby mineralization of the MG by the generated hydroxyl radicals (•OH) under the influence of visible radiation coupled with 6.34 W·mL−1 ultrasonic power. In the present study the application of photodegradation process with sonochemistry results in 99% of MG mineralization without effecting the material structure unlike happens in the case adsorption process. So, the secondary pollution (generally happens in case of adsorption) can be avoided by reusing the spent material for another application instead of disposing it. Thus, the ecofriendly synthesis protocol, ease in design of experimentation like use of solar irradiation instead of electric power lamps, reusability and high efficiency of the material suggested the study to be potentially economical for industrial development at pilot scale towards wastewater remediation.

Enantioselective Biocatalytic Reduction of Hexan-2-one, Catalyzed by Petroselinum crispum Cells

A method for the synthesis of (2S)-(+)-hexan-2-ol, a precursor of a number of drugs, by the enantioselective biocatalytic reduction of a prochiral hexan-2-one, catalyzed by P. crispum cells, is proposed. Conditions for the synthesis of (2S)-(+)-hexan-2-ol within 48 h in a yield of 98% and an optical purity of 99% ee in the presence of isopropanol (3%) and in a yield of 85% and an optical purity of 90% ee in the presence of ethanol (2%) were found. It was shown that when the time of biotransformation in the presence of isopropanol and ethanol was prolonged to 144 h, the yield and optical purity of (2S)-(+)-hexan-2-ol significantly decrease, and the concentration of the starting ketone increases. With 1% isopropanol and 3 and 4% ethanol, only the starting hexan-2-one was present in the reaction mixture.

Effect of graphene oxide content on morphology and topography of polysulfone‐based mixed matrix membrane for permeability and selectivity of carbon dioxide and methane

AbstractIn this work, mixed matrix membranes based on polysulfone containing different contents of graphene oxide were prepared using a phase inversion process. The morphological, and structural properties as well as surface features of the samples were investigated by means of field‐emission scanning electron microscopy, infrared and x‐ray diffraction spectroscopies, as well as atomic force microscopy. The gas permeation/selectivity behavior of graphene oxide‐loaded polysulfone samples was studied using pure carbon dioxide, and methane. Morphological images depicted that the addition of graphene oxide to polysulfone in the presence of isopropyl alcohol as non‐solvent was reduced the numbers of finger‐like macro‐voids, and caused to the formation of teardrop‐like structures. Besides the x‐ray patterns and Fourier transform infrared spectra confirmed the graphene oxide nano‐plates and polysulfone with no chemical interactions, the atomic force microscopic patterns demonstrated a decrease in the average roughness of samples’ surface from 21.85 nm for plain polysulfone membrane to 5.02 nm for ones containing 2 weight percentages of graphene oxide as the optimum sample. Finally, a significant enhancement for the selectivity of carbon dioxide/methane with the value of 38.08 has been observed by the sample which was approximately 22‐fold more than that of plain polysulfone.

An Efficient Heterogeneous Acid Catalyst DICAT-1 for One-Pot Conversion of Sucrose into 5-(Hydroxymethyl)furfural

5-(Hydroxymethyl)furfural (HMF) is a trending biogenic platform molecule for the production of multiple energy, fuel, and chemical products, and it can be synthesized by using C6 sugars and/or its oligomers and polymers. In the present paper, the heterogeneous solid acid catalyst DICAT-1, with characteristic properties, exhibited one-pot conversion of sucrose into 5-HMF. The DICAT-1 triggered in-situ hydrolysis, isomerization, and dehydration of sucrose to yield 5-HMF in the presence of the low boiling point (LBP) green solvent isopropyl alcohol (IPA) in combination with the cosolvent DMSO. Of the tested solvents water, IPA, DMF, DMSO, and IPA:DMSO, the use of IPA in combination with DMSO shows the profound effect on sucrose dehydration. Exploration of DICAT-1 in the presence of IPA:DMSO (70:30 v/v) resulted in a 5-HMF yield of >77%. The central composite design model (CCD) was used to find out the best operating conditions for the solvent ratio and catalyst concentration. Moreover, the process intensification study depicted the remarkable effect of solvent, reaction temperature, time, sucrose concentration, catalyst concentration, and autogenous pressure of the solvent on the yield of 5-HMF. In- process analysis was conducted by using HPLC, and the product was characterized by using HPLC, ATR-FTIR, GC-MS, and LC-MS. The plausible reaction mechanism for the DICAT-1-mediated sucrose to 5-HMF conversion was also proposed. Characteristic properties of DICAT-1 such as the porosity and presence of accessible −SO3H acid active sites favor the one-pot conversion. Moreover, the catalyst recyclability test for five consecutive runs showed consistent 5-HMF yields. Thus, DICAT-1 was found to be an efficient and robust catalyst for sucrose dehydration in the IPA:DMSO solvent mixture.

Gamma irradiation of graphene quantum dots with ethylenediamine: Antioxidant for ion sensing

Due to the low consumption of chemicals, the absence of toxic residual side products, the procedure simplicity and time-saving aspects, gamma irradiation offers advantages over the classical chemical protocols. We successfully employed gamma irradiation in order to introduce N-atoms in Graphene Quantum Dots (GQDs). By irradiating GQDs water dispersions in the presence of isopropyl alcohol and ethylenediamine, at doses of 25, 50 and 200 kGy, we attached amino groups onto GQDs in a single synthetic step. At the same time, a chemical reduction is achieved, too. Selected conditions induced incorporation of N-atoms within GDQs atomic lattice (around 3 at%), at all applied doses. Additionally, the C-atoms percentage was highly increased, from 63 to 79 at% or higher. The zeta potential of dots changed from −34.6 to +9.1 mV, due to the modification of functionalizing groups localized at the surface. Produced chemical changes lead to the desired alteration of the GQDs optical properties, such as an increased photoluminescence intensity, a higher photoluminescence quantum yields (from 2.07 to 18.40%) and a narrowing of the spectral features in the emission spectra. The ability of gamma-irradiated GQDs to quench free radical species was investigated and positively assessed; additionally, non-enzymatic optical detection of Cu(II) ions using GQDs as a sensor was studied and the detection limits are herein reported. These results suggest that GQDs can be potentially applied as smart photoluminescent sensors for metal cations.

Aminomethoxy derivatives of norbornenylmethanol as biocorrosion inhibitors

Norbornenylmethanol was synthesized by the reaction of cyclopentadiene and allyl alcohol, on the basis of which aminomethoxy derivatives of norbornenylmethanol were synthesized in the presence of formaldehyde and secondary amines by Mannich condensation. The yield of the target products was 43-71%. On the basis of 5-morpholinomethoxymethylbicyclo[2.2.1]-hept-2-ene and hexylbromide (1:1) in the presence of isopropyl alcohol, its complex was obtained. The physic-chemical properties of the synthesized compounds and the resulting complex were determined, their 1% solutions in isopropyl alcohol and 5% solution of 5-morpholinomethoxymethylbicyclo[2.2.1]-hept-2-ene were prepared. Their influence on the vital activity of sulfate-reducing bacteria of the type «Desulfovibrio desulfuricans» in three concentrations (5; 50; 100 mg/L) was studied. Bactericide inhibitors used in industry – AMDOR IK-7 and AMDOR IК-10 were taken as standards. It was determined that all the synthesized compounds and the resulting complex showed high bactericidal properties, moreover, compounds obtained on the basis of cyclic secondary amines showed a higher bactericidal effect against sulfate-reducing bacteria, unlike compounds obtained on the basis of aliphatic secondary amines. Considering that these aminomethoxy derivatives of norbornenylmethanol affect bacteria at very low concentrations, they can be proposed as effective inhibitors against sulfate-reducing bacteria.

Photocatalytic reduction for graphene oxide by PbTiO3 with high polarizability and its electrocatalytic application in pyrrole detection

Quick recombination of photogenerated electrons and holes in photocatalytic process remains a huge challenge. And the routine efforts are concentrated on heterojunction, metal decoration and surface defect strategies. PbTiO3 as a typical perovskite ferroelectrics is with a strong built-inelectric field as self-junction caused by internal spontaneous polarization, facilitating the charge separation in the photocatalytic process. Here, under UV irradiation, L-shaped PbTiO3 with active (1 1 0) facet as a photocatalyst was applied to photo-reduce graphene oxide (GO), where a specific reduced graphene oxide (rGO)/PbTiO3 composite was synthesized in presence of isopropanol, a hole-trapping agent. According to the linear optical properties, the polarizability of PbTiO3 is calculated to 1.01 × 10−23 cm3 (2.68 times that of P25 (TiO2)), inducing the photo-excited charge separation by PbTiO3. Based on XPS characterization, a TiOC chemical bond is identified on the interface between rGO and PbTiO3. The response peak current for an electrochemical sensor based on rGO/PbTiO3 was proportional to the concentration of pyrrole (6.6 × 10−9–3.1 × 10−7 M, R2 = 0.999), and an extremely low limit reaches to 2.38 × 10−9 M. In addition, polypyrrole during the pyrrole detection was realized by the multi-cycle oxidation process. And also, the electrochemical detection has been successfully applied for the pyrrole quantification in real samples.

Highly Active CuFeAl-containing Catalysts for Selective Hydrogenation of Furfural to Furfuryl Alcohol

CuFe-containing catalysts with different copper oxide content were prepared by fusion of metal salts. The obtained catalyst showed high activity in the hydrogenation of furfural to furfuryl alcohol (FA) in the batch reactor in the presence of isopropanol as a solvent at a temperature of 100 °C and a hydrogen pressure of 6.0 MPa. The yield of FA and furfural conversion are 97% and 98%, respectively. In the solvent-free reaction in the flow-type reactor; the most active catalyst Cu20Fe66Al14 leads to the 96% formation of FA with 100% conversion of furfural at liquid hourly space velocity (LHSV) = 1 h−1; 160 °C and a hydrogen pressure of 5.0 MPa during 30 h. According to the X-ray diffraction (XRD) method, the active component of the spent and fresh Cu20Fe66Al14 catalyst is the same and is represented by metallic copper and Fe3O4-type spinel. Using different methods, the formation of active sites was investigated.

(Benz)Imidazolin-2-iminato Aluminum, Zinc, and Magnesium Complexes and Their Applications in Ring Opening Polymerization of ε-Caprolactone.

Synthesis and characterization of a new family of aluminum, magnesium, and zinc complexes supported by (benz)imidazolin-2-iminato ligands are reported herein. Under different reaction conditions, (benz)imidazolin-2-imine ligands reacted with metal alkyl precursors to afford the corresponding complexes, displaying mononuclear, binuclear, and trinuclear structures. Reaction in 1:1 stoichiometry at room temperature afforded the simple Lewis acid-base adducts, which exhibited distorted tetrahedral geometries around the metal centers, whereas high temperature reactions gave rise to dimeric complexes, with each metal bridging two (benz)imidazolin-2-imine ligands to form a four-membered metallacycle ring at the center of the complexes. The catalytic ring opening polymerization (ROP) of ε-caprolactone was studied using these complexes as precatalysts in the presence of isopropanol, and very high activities were observed, affording high/medium molecular weight poly(ε-caprolactone) products with low polydispersity indices. Detailed kinetic studies revealed that the polymerizations proceeded in a living manner and molecular weights of the polymers could be precisely controlled.