Isobutanol Research Articles

A study on the volatile compounds in Japanese alcoholic beverage (Awamori) produced from Thai rice varieties

Awamori is a famous alcoholic beverage brewed in the Southern part of Japan. Thai rice is well known and there are many varieties of rice including white rice and pigmented rice. This research aimed to study the properties and volatile compounds of Awamori produced from five Thai rice varieties including KDML105, Chainat, RD6, brown KDML105, and riceberry rice. Rice koji was prepared by inoculating the steamed rice with tane-koji from Aspergillus awamori at 0.2% by weight. Then, water and Saccharomyces cerevisiae were added and alcoholic fermentations were performed at around 2 weeks. The production of alcohol and pH changes during the liquid fermentation were monitored, and volatile compounds of the Awamori were determined by gas chromatography-mass spectrophotometry (GC-MS). The highest soluble solid and alcohol content were observed in the fermentation of KDML 105. The alcohol content after 2 weeks of fermentation ranged from 14.5-18 %, with the pH around 4.02-4.5. The same volatile compounds, ethyl alcohol, isobutyl alcohol, isoamyl alcohol, phenylethyl alcohol, isoamyl acetate, ethyl laurate, ethyl linoleate, with the flavor descriptions as alcohol, wine-like, mushroom-like, floral, rose, fruity, banana, sweet, ice-cream, mild fatty, oily, and honey-like odors were detected in all samples from Thai rice while KDML105 presented greater diversity of volatile compounds than the other Thai rice.

Dual-ligand Cu-based MOFs for electrocatalytic reduction of NO3–

Electrocatalytic nitrate reduction reaction (ENRR) to recyclable NH3 or environmental-friendly N2 is a sustainable technology. In this study, we prepared three dual ligand Cu-based metal organic framework (Cu@MOFs) for efficient ENRR. The batch ENRR test revealed that Cu-bip-BTC exhibited the best performance in terms of NH3-N selectivity (61.64%), NH3-N yield (12.09 ×103 µgCu·h–1 mg–1) and faradaic efficiency for NH3 (80.97%) at −0.58 V vs. RHE. The ligands and coordination of Cu@MOFs affect the electronic structure of Cu and the adsorption performance of NO3–, leading to differences in the performance of the electrocatalytic reduction of nitrate. The quenching experiment of tert-butanol (TBA) demonstrates that NO3– is directly reduced by electrons on Cu@MOFs at −0.58 V, and in-situ spectrometric analysis identified the intermediates and pathways of ENRR. Cu-bip-BTC has the highest NH3-N selectivity due to its faster kinetic reaction rate, stronger inhibition of the hydrogen evolution reaction, and higher NO3– adsorption energy. In addition, ENRR combined with breakpoint chlorination reactions suggests that achieving nitrogen elimination is feasible, and this study provides a strategy for the application of dual-ligand Cu-based MOFs in ENRR.

ЭКСПРЕСС-СПОСОБ ОПРЕДЕЛЕНИЯ БИОДИЗЕЛЬНОГО ТОПЛИВА В СМЕСЕВОМ ТОПЛИВЕ МЕТОДОМ ТОНКОСЛОЙНОЙ ХРОМАТОГРАФИИ

Biodiesel fuel (BF) can be an additive to diesel fuel used in agricultural production to increase the cetane number and lubricating properties. Such an additive can be biodiesel fuel. Regulations allow the addition of 7% BF to petroleum fuels. An express method that allows the consumer to quickly determine its presence was developed. The possibility of determining BF in a mixture with petroleum by thin-layer chromatography (TLC) has been studied for the first time. Samples of BF obtained by transesterification of rapeseed, sunflower, linseed, corn, radish and camelina oils were synthesized for this investigation. The solubility of BF in a number of organic solvents was studied for the first time to select the suitable eluent. It has been established that biodiesel fuel is highly soluble not only in non-polar hydrocarbons (benzene, toluene, octane, petroleum ether), but also in chloroform and monohydric alcohols of normal and branched structure (propyl, butyl, isobutyl, and isoamyl alcohols). Biodiesel is insoluble in solvents with a higher dielectric constant (such as acetone or glycerol). The same solvents were investigated as eluents for the separation of fuel oil and biodiesel by thin layer chromatography. It has been shown that alcohols, chloroform and acetone are not suitable as eluents; but it is possible to use toluene. The value of the retardation factor Rf for the main spot of petroleum fuel is 0.86, and for biodiesel fuel is 0.6 (eluent is toluene). It has been established that it is possible to determine the presence of biodiesel fuel synthesized from various types of oils using TLC (eluent is toluene). Also, petroleum ether can be recommended as an eluent for analysis in the field. The TLC method can be used to detect the presence of biodiesel at concentrations from 2% and above.

Degradation of phenol with Mn-CoOX/γ-Al2O3 catalytic ozonation enhanced by high gravity technology

In this study, Mn-CoOX/γ-Al2O3 (MCA) was prepared by impregnation for catalytic ozonation of phenol in a rotating packed bed (RPB), and the effects of high gravity factor (β), liquid flow rate (QL), initial solution pH and gaseous ozone concentration (CO3) on the mineralization of phenol were explored. The results show that the degradation rate of phenol (ηphenol) reaches 100% at 9 min and the mineralization rate (ηTOC) reaches 95.01% at 45 min under conditions of β = 104, CO3= 80 mg L-1, QL = 80 L/h, and pH = 6. Compared with the bubbling reactor (BR)/MCA/O3 and O3/RPB systems, the ηTOC of the MCA/O3/RPB system is increased by 25.81% and 40.85%, respectively. The electron paramagnetic resonance (EPR) results reveal that hydroxyl radical (·OH) plays a critical role in the degradation of phenol by MCA catalyzed ozonation. The quenching experiment using tertiary butyl alcohol (TBA) as a scavenger of ·OH reveals that the ratio of direct and indirect degradation of phenol is 16:9. The intermediates generated during the degradation of phenol were detected by gas chromatography-mass spectrometry (GC–MS), and possible degradation pathways were proposed. In conclusion, MCA-catalyzed ozonation and RPB have a synergistic effect on ·OH initiation and improve the degradation and mineralization of phenol. This study provides a new perspective for the degradation of phenol.

An Efficient and Mild Method for the Alkylation of p-Cresol with tert-Butyl Alcohol

The synthesis 2-tert-butyl-4-methylphenol is of great significance because of its wide application in industry, and the development of a highly efficient catalyst is necessary for the alkylation of p-cresol and tert-butyl alcohol. Here, an efficient and mild method was established. Caprolactam was chosen as the hydrogen-bonding acceptor; p-toluenesulfonic acid was employed as the hydrogen-bonding donor, and a deep eutectic solvent (DES) was prepared to catalyze the alkylation reaction. The structure of the deep eutectic solvent catalyst was characterized by 1H NMR spectra, thermogravimetric analysis, and Fourier transform infrared spectra (FT-IR). In addition, response surface design based on the Box–Behnken method was employed to optimize the alkylation reaction process parameters, and the study of reaction kinetics was also carried out subsequently. The recycle performance of the catalyst was evaluated by recovery experiments, and a good result was obtained. By drawing comparisons with the literature reported, we provide a mild method for the synthesis of 2-tert-butyl-4-methylphenol.

Direct Tertiary Butyl Alcohol Formation via Catalytic Liquid Phase Isobutane Oxidation with Molecular Oxygen

A safe one-pot catalytic process for directly producing tertiary butyl alcohol (TBA) from liquid-phase isobutane oxidation with oxygen is demonstrated. This is achieved by operating outside the vapor phase flammability envelope and catalytically decomposing tertiary butyl hydroperoxide (TBHP), the main product of homogeneous isobutane oxidation, at 125 °C and 35 bar. Among a dozen heterogeneous metal-based catalysts tested, amorphous MnO2 (AMO) was found to be roughly an order of magnitude more active than supported Pd, Co, Au, and Nb-based catalysts for TBHP decomposition to TBA. As a result, high TBA/TBHP (up to 20.4) selectivity was achieved during isobutane oxidation in the presence of the AMO catalyst. The yield of gas phase C1 products was <1% and only a minor amount of acetone was produced as a β-scission byproduct. The use of n-hydroxy phthalimide (NHPI) as an initiator was found to enhance the TBA yield. This process provides a possible low energy pathway for making isobutylene from isobutane, avoiding the energy-intensive dehydrogenation and isobutane/isobutylene separation steps.

Microemulsion and microsuspension polymerization of methyl methacrylate in surfactant-free microemulsions (SFME)

HypothesisThis article presents a free-radical polymerization method in a mesostructured system – free of any surfactants, protective colloids, or other auxiliary agents. It is applicable for a large variety of industrially relevant vinylic monomers. The aim of this work is to study the impact of surfactant-free mesostructuring on the polymerization kinetics and the polymer derived. ExperimentsSo-called surfactant-free microemulsions (SFME) were investigated as reaction media with a simple composition comprising water, a hydrotrope (ethanol, n-propanol, isopropanol, tert-butyl alcohol), and the monomer as the reactive oil phase (methyl methacrylate). Polymerization reactions were performed using oil-soluble, thermal- and UV-active initiators (surfactant-free microsuspension polymerization) and water-soluble, redox-active initiators (surfactant-free microemulsion polymerization). Structural analysis of the SFMEs used and the polymerization kinetics were followed by dynamic light scattering (DLS). Dried polymers were analyzed with regard to their conversion yield by mass balance, the corresponding molar masses were determined using gel permeation chromatography (GPC), and the morphology was investigated by light microscopy. FindingsAll alcohols are suitable hydrotropes to form SFMEs, except for ethanol, which forms a molecularly disperse system. We observe significant differences in the polymerization kinetics and the molar masses of the polymers obtained. Ethanol leads to significantly higher molar masses. Within a system, higher concentrations of the other alcohols investigated give rise to less pronounced mesostructuring, lower conversions, and lower average molar masses. It could be demonstrated that the effective concentration of alcohol in the oil-rich pseudophases as well as the repulsive effect of the surfactant-free, alcohol-rich interphases constitute the relevant factors influencing polymerization. Concerning the morphology, the polymers derived range from powder-like polymers in the so-called “pre-Ouzo region” over porous-solid polymers in the bicontinuous region to dense, almost compacted, transparent polymers in unstructured regions, comparable to the findings for surfactant-based systems reported in the literature. Polymerizations in SFME comprise a new intermediate between well-known solution (i.e., molecularly dispersed) and microemulsion respectively microsuspension polymerization processes.

Activation of persulfate by heat, FeNPs, and Fe/MnO2 for the advanced oxidation processes

In this work, we used only persulfate (S2O82−), Fe0/S2O82−, Fe/MnO2/S2O82− systems as an activator to generate reactive radical species for the chemical oxidation of Congo red azo dye. The formation of a new colored species at 363 nm and its decomposition was observed at a specific reaction condition for the first time. Congo red-S2O82− redox reaction was very slow at 22 °C. After the addition of small amount of Fe/MnO2, the red color was decolorized completely within 6 min. The maximum degradation of Congo red was achieved at optimum parametric values of [S2O82−] = 0.2 mM, [Congo red] = 0.6 mM, amount of Fe/MnO2 = 10 mg, pH = 6.5, and temperature = 22 °C. The presence of MnO2 accelerates the generation of sulfate radicals (SO4−•) during the Fenton- like reaction between Fe/MnO2 and S2O82− due to the synergistic effect. The activation energy was found to be 40.1, 48.0, and 92.2 kJ/mol for Fe/MnO2/S2O82−, Fe/S2O82−, and only S2O82−, respectively. The oxidation of Congo red follows complex order kinetics with respect to pH as well as concentrations of S2O82−. Chemical probes experiments with various radical scavengers such as ethanol, tertiary butyl alcohol (TBA), and potassium iodide showed that the SO4−• radicals participate effectively in situ chemical oxidation of Congo red. Cationic cetyltrimethylammonium bromide (CTAB) retarded the persulfate activation by Fe/MnO2 significantly. The morphology of Fe/MnO2 was determined by XRD, EDX, FTIR, SEM, and TEM.

Experimental and numerical investigations for compressive behavior of porous hydroxyapatite bone scaffold fabricated via freeze-gel casting method

Artificial bone scaffolds with a porosity of ≥64% were manufactured using hydroxyapatite (HA). The Freeze-gel Casting method using tert-butyl alcohol (TBA) as a solvent was adopted to maintain proper mechanical strength. The manufactured HA scaffold had excellent internal connectivity owing to the continuous connection of the long columnar pores and arrangement of the constant pore walls. For the HA scaffold, compression tests at different strain rates under uniaxially compressed loads were performed, and the compressive behavior according to the strain rate was analyzed. A maximum yield stress of 2–3 MPa was observed, and the overall compressive behavior was divided into elastic, plateau, and densification sections, which were different from the brittleness behavior of ordinary ceramics and similar to that of polymer materials. The compressive behavior of the HA scaffold was successfully simulated by applying the Frank–Brockman–Zairi constitutive model used to simulate elasto-viscoplastic material behavior. Seven material parameters belonging to the constitutive equation were proposed for the HA scaffold by adopting a deterministic approach for material parameter identification. Models can be developed from methods for simulating the mechanical behavior of a porous ceramic scaffold to predict the long-term mechanical behavior of the scaffold inserted in vivo, which may help in bone defects recovery.

Microflow system for controlled synthesis of ethylene-vinyl acetate copolymers: Continuous copolymerization and kinetic study

Ethylene content in ethylene–vinyl acetate copolymers (EVA) is a key factor that determines its further usage. While conventional batch reactor for EVA synthesis faces the problem of heterogeneous reaction environment and temperature control. A microflow system was designed to avoid these problems and facilitate the synthesis of EVA with controlled ethylene content. Continuous flow synthesis of EVA by solution free radical copolymerization was realized homogeneously based on this microflow system. 13C NMR spectra indicate that EVA obtained in microflow system has less ethylene concentrated sequence than EVA obtained in batch reactor. By operating the microflow system in a stop-flow method, we developed a simple kinetic model of copolymerization and measured the reactivity ratios of ethylene and vinyl acetate copolymerization in tert-butyl alcohol and dimethyl carbonate. The microflow system is demonstrated to be a powerful tool in kinetic and mechanism study and engineering application of copolymerization processes involving monomers which are gas phase under conventional condition.

Picolinic Acid-Mediated Catalysis of Mn(II) for Peracetic Acid Oxidation Processes: Formation of High-Valent Mn Species.

Metal-based advanced oxidation processes (AOPs) with peracetic acid (PAA) have been extensively studied to degrade micropollutants (MPs) in wastewater. Mn(II) is a commonly used homogeneous metal catalyst for oxidant activation, but it performs poorly with PAA. This study identifies that the biodegradable chelating ligand picolinic acid (PICA) can significantly mediate Mn(II) activation of PAA for accelerated MP degradation. Results show that, while Mn(II) alone has minimal reactivity toward PAA, the presence of PICA accelerates PAA loss by Mn(II). The PAA-Mn(II)-PICA system removes various MPs (methylene blue, bisphenol A, naproxen, sulfamethoxazole, carbamazepine, and trimethoprim) rapidly at neutral pH, achieving >60% removal within 10 min in clean and wastewater matrices. Coexistent H2O2 and acetic acid in PAA play a negligible role in rapid MP degradation. In-depth evaluation with scavengers and probe compounds (tert-butyl alcohol, methanol, methyl phenyl sulfoxide, and methyl phenyl sulfone) suggested that high-valent Mn species (Mn(V)) is a likely main reactive species leading to rapid MP degradation, whereas soluble Mn(III)-PICA and radicals (CH3C(O)O• and CH3C(O)OO•) are minor reactive species. This study broadens the mechanistic understanding of metal-based AOPs using PAA in combination with chelating agents and indicates the PAA-Mn(II)-PICA system as a novel AOP for wastewater treatment.

(111)-Dominated Perovskite Films by Antisolvent Engineering.

Fabricating perovskite films with a dominant crystal orientation is an effective path to realizing quasi-single-crystal perovskite film, which can eliminate the fluctuation of the electrical properties in films arising from grain-to-grain variations, and improve the performance of perovskite solar cells (PSCs). Perovskite (FAPbI3 ) films based on one-step antisolvent methods usually suffer from chaotic orientations due to the inevitable intermediate phase conversion from intermediates of PbI2 •DMSO, FA2 Pb3 I8 •4DMSO, and δ-FAPbI3 to α-FAPbI3 . Here, a high-quality perovskite film with (111) preferred orientation ((111)-α-FAPbI3 ) using a short-chain isomeric alcohol antisolvent, isopropanol (IPA) or isobutanol (IBA), is reported. The interaction between IPA and PbI2 leads to a corner-sharing structure instead of an edge-sharing PbI2 octahedron, sidestepping the formation of these intermediates. With the volatilization of IPA, FA+ can replace IPA in situ to form α-FAPbI3 along the (111) direction. Compared to randomly orientated perovskites, the dominantly (111) orientated perovskite ((111)-perovskite) exhibits improved carrier mobility, uniform surface potential, suppressed film defects and enhanced photostability. PSCs based on the (111)-perovskite films show 22% power conversion efficiency and excellent stability, which remains unchanged after 600h continuous working at maximum power point, and 95% after 2000h of storage in atmosphere environment.

Comments on the paper “The phenomenon of ‘‘partial isobaric compression” of urea as a solute in tertiary butanol: Comparison with a similar effect in the (methanol + urea) system” by E.V. Ivanov, E.Yu. Lebedeva [J. Mol. Liq. 370 (2023) 121039-10

This work is a commentary on an article by Ivanov and Lebedeva that appeared in this journal. The name of the phenomenon of partial molar volume decrease with temperature increase formulated in the paper as “partial isobaric compression“ is incorrect.

Energy-saving strategy for separation of methylcyclohexane/tert-butanol azeotrope

With the increase in industrialization, researchers are striving to pursue energy-saving and environment-friendly separation technologies. In this regard, effective separation of azeotropes is one of the focus areas in recent years. According to the characteristics of methylcyclohexane (MCH) and tert-butanol (TBA) azeotropes, a pressure-swing distillation (PSD) process is established in the current work. Combined with steam recompression and heat integration, two improved separation processes for reduced energy consumption are designed. The operating parameters had a significant effect on the efficiency and cost of the process. Therefore, the selection of parameters was discussed in detail. The proposed PSD processes were evaluated according to the assessment indices including total energy consumption (TEC), CO2 emissions and total annual cost (TAC). The results showed that the improved processes obviously decreased the energy consumption and improved the economy whether it is heat pump pressure swing distillation (HP-PSD) or heat integrated pressure swing distillation (HI-PSD). The HI-PSD process can achieve a TAC savings of 30.86%, TEC reduction of 37.59% and CO2 reduction of 36.34%. The HP-PSD process is found to be the most economical and environment-friendly process among the studied processes, and could achieve 34.92% TAC savings, 42.89% TEC reduction and 50.98% CO2 reduction.

Chemical Release Accident Caused by the Abnormal Reaction of Potassium Permanganate Mixtures during Optical Film Manufacturing: A Brief Case Review

Small- and large-scale accidents often occur in workplaces handling hazardous chemical substances. These accidents are usually caused by leaks, explosions, fires and complex chemicals; a large proportion of these chemical accidents are caused by leaks. A chemical release accident that injured four people occurred during an optical film-manufacturing process. This report analyzes the causes of this accident and provides effective measures for accident prevention. This accident was caused by an abnormal reaction during the input of raw materials prior to their heating. Tertiary butyl alcohol (t-BuOH), distilled water (DW), and potassium permanganate (KMnO4) were mainly used in this process. We found that this mixture reacted with unknown impurities. After KMnO4 was added to the mixture of t-BuOH and DW, a large amount of heat was suddenly released from the reactor for one minute. In particular, a small amount of methanol (4%), which could have entered the mixture during the cleaning process, and seal oil containing glycerin (13%) were suspected to be the key materials influencing the rapid reaction. Given the significant findings about this accident, the precautionary technical/administrative measures we provide herein may help prevent such accidents in future.

Permanganate activation by glucose-derived carbonaceous materials for highly efficient degradation of phenol and p-nitrophenol: Formation of hydroxyl radicals and multiple roles of carbonaceous materials

Owing to its inertness toward refractory organic pollutants and the release of Mn2+, the use of permanganate was limited in soil and groundwater remediation. The present study proposed an improvement strategy based on glucose-derived carbonaceous materials, which enhanced the potential of permanganate degrading organic pollutants. The glucose-derived carbonaceous material with 1000 °C charring temperature was named C1000, which was exploited in activating KMnO4 for the elimination of refractory organic contaminants. The addition of C1000 in the KMnO4 system triggered the degradation of refractory p-nitrophenol and quicken phenol degradation. Unlike the detection of Mn(III) species in a solo KMnO4 system, the presence of C1000 facilitated the formation of •OH in the KMnO4 system, which was confirmed by the use of quenchers such as methanol, benzoic acid, tertiary butanol, and carbonate. Additionally, the glucose-derived carbonaceous material played multiple roles in improving the performance of permanganate, including the enrichment of organic pollutants, donation of electrons to permanganate, and acting as an electron shuttle to facilitate the oxidation of organic pollutants by permanganate. The study's novel findings have the potential to expand the use of permanganate in the remediation of organic pollutants.

Fungal, host andnon‐hostvolatiles modify attraction of the walnut twig beetle,Pityophthorus juglandis, to pheromone lures

AbstractThousand Cankers Disease (TCD) of walnut trees is caused by the pathogenic fungusGeosmithia morbidavectored by the walnut twig beetle (WTB)Pityophthorus juglandis. Monitoring efforts for WTB rely on pheromone‐baited traps, but lures are likely effective at attracting beetles only over short distances. Fungal‐derived kairomones may increase the efficacy of current lures, while additional volatiles may repel beetles from valuable trees.The objective of this study was to determine the extent to which fungal, host and non‐host volatiles modify the attraction of WTB to pheromone‐baited traps. A trapping study that combined fungal, host‐associated and non‐host compounds with WTB‐pheromone lures was conducted over three years in black walnut plantations experiencing a TCD outbreak in Walla Walla, WA.Traps baited with pheromone andG. morbidavolatiles (i.e., isoamyl and isobutyl alcohol) consistently attracted more WTB, while other fungal volatiles inconsistently increased attraction compared to those baited with pheromone lure alone. This is the first field study that demonstrates fungal volatiles can increase the attraction of a bark beetle to its pheromone in a hardwood system.One fungal (benzyl alcohol) and two additional volatiles (limonene, piperitone) repelled WTB from pheromone‐baited traps. Although limonene is known to repel WTB, this is the first demonstration that benzyl alcohol and piperitone repel a bark beetle.Fungal volatiles may increase the efficacy of monitoring efforts and may play an important role in management tactics for WTB, especially in detecting the introduction and establishment of nascent populations and protecting trees from colonizing beetles.

In-situ hydrogen peroxide formation and persulfate activation over banana peel-derived biochar cathode for electrochemical water treatment in a flow reactor

Electrochemical advanced oxidation processes (EAOPs) are effective for the removal of organic contaminants from groundwater. The choice of an affordable cathode material that can generate reactive oxygen species (ROS) such as hydrogen peroxide (H2O2) and hydroxyl radicals (•OH) will increase practicality and cost effectiveness of EAOPs. Carbon enriched biochar (BC), which is derived from pyrolysis of biomass, has emerged as an inexpensive and environmentally-friendly electrocatalyst for removing contaminants from groundwater. In this study, a banana peel-derived biochar (BP-BC) cathode packed in a stainless steel (SS) mesh was used in a continuous flow reactor to degrade the ibuprofen (IBP), as a model contaminant. The BP-BC cathodes generate H2O2 via a 2-electron oxygen reduction reaction, initiate the H2O2 decomposition to generate •OH, adsorb IBP from contaminated water, and oxidize IBP by formed •OH. Various reaction parameters such as pyrolysis temperature and time, BP mass, current, and flow rate, were optimized to maximize IBP removal. Initial experiments showed that H2O2 generation was limited (∼3.4 mg mL−1), resulting in only ∼ 40% IBP degradation, due to insufficient surface functionalities on the BP-BC surface. The addition of persulfate (PS) into the continuous flow system significantly improves the IBP removal efficiency via PS activation. The in-situ H2O2 formation and PS activation over BP-BC cathode results in concurrent generation of •OH and sulfate anion radicals (SO4•−, a reactive oxidant), respectively, which collectively achieve ∼ 100% IBP degradation. Further experiments with methanol and tertiary butanol as potential scavengers for •OH and SO4•− confirm their combined role in complete IBP degradation.

One-Step Synthesis of Transition Metal Dichalcogenide Quantum Dots Using Only Alcohol Solvents for Indoor-Light Photocatalytic Antibacterial Activity.

In this study, we report a one-step direct synthesis of molybdenum disulfide (MoS2) and tungsten disulfide (WS2) quantum dots (QDs) through a solvothermal reaction using only alcohol solvents and efficient Escherichia coli (E. coli) decompositions as photocatalytic antibacterial agents under visible light irradiation. The solvothermal reaction gives the scission of molybdenum-sulfur (Mo-S) and tungsten-sulfur (W-S) bonding during the synthesis of MoS2 and WS2 QDs. Using only alcohol solvent does not require a residue purification process necessary for metal intercalation. As the number of the CH3 groups of alcohol solvents among ethyl, isopropyl, and tert(t)-butyl alcohols increases, the dispersibility of MoS2/WS2 increases. The CH3 groups of alcohols minimize the surface energy, leading to the effective exfoliation and disintegration of the bulk under heat and pressure. The bulky t-butyl alcohol with the highest number of methyl groups shows the highest exfoliation and yield. MoS2 QDs with a lateral size of about 2.5 nm and WS2 QDs of about 10 nm are prepared, exhibiting a strong blue luminescence under 365 nm ultraviolet (UV) light irradiation. Their heights are 0.68-3 and 0.72-5 nm, corresponding to a few layers of MoS2 and WS2, respectively. They offer a highly efficient performance in sterilizing E. coli as the visible-light-driven photocatalyst.

Volumetric Properties of a Solution of tert-Butyl Alcohol in Carbon Tetrachloride: MD Modeling

Models of solutions of tert-butyl alcohol (TBA) in carbon tetrachloride (CTC) are obtained via all-atom molecular dynamics modeling. The excess volume of the solution and the apparent and intrinsic (geometric) volumes of both components are calculated throughout the range of concentrations. It is shown that the apparent and intrinsic molar volumes of TBA in the limit of low concentrations in solution are notably larger than in pure alcohol. At the same time, their values fall rapidly in a narrow range of concentrations (from 0 to 0.1 mole fractions), and then move almost linearly to their limit values in alcohol. It is found that such behavior of the volumetric characteristics of TBA is due to the specific association of alcohol at low concentrations because of the hydrogen bonding among TBA molecules.