Search

Internal combustion engines are quite widely used today. Much work is being done to reduce the environmental damage of internal combustion engines, reduce fuel consumption and improve engine performance values. Despite quite a lot of work done to date, it is known that due to the increase in the number of gasoline engines, their environmental damage is excessive. In this study, the effect of 2-Propanol use on emission characteristics was investigated. 2-Propanol (%5, %10, and %15 by volume) mixed with gasoline fuel, tests were conducted with a direct injection engine. Tests were conducted under full load conditions. Compared to the gasoline reference fuel and the blended fuels prepared with different percentages, it was observed that the CO and HC emission values decreased, and the CO2, O2, and NO emission values increased as a result of the use of 2-Propanol.

The middle vessel batch distillation column is an alternative to the regular batch distillation column. This configuration allows simultaneous separation of the light fraction (accumulated at top), heavy fraction (accumulated at bottom) and the intermediate fraction (accumulated in the middle vessel) in a single column. The objective of this article is to extensively analyse and discuss different control systems for the middle vessel batch distillation column (MVBDC) and dynamically optimize the column. Three control structures such as composition level cascade, composition temperature cascade, and temperature control system, have been tested and evaluated. Further, a dynamic optimization study has been performed on the control system providing the fastest separation. The optimizer is set to minimize the total energy consumed during the process. This resulted in a decrease in batch time from 26.8 to 25.2 h and a 13.5% decrease in overall energy usage. The presented dynamic optimization technique and control system design is useful for improving the performance of the MVBDC.

CeO2 nanoshapes, cubes with dominant (1 0 0) facets and octahedra with dominant (1 1 1) facets, were synthesized to investigate the influence of surface structure on acid-base properties. An optimization of calcination temperatures, coupled with Raman and TEM, was employed to minimize the intrinsic (Frenkel-type) defect sites and their potential complications on the facet studies involved in this work. The acid-base properties of these CeO2 nanoshapes were characterized with in situ pyridine and CO2 adsorption using infrared spectroscopy and quantified using pyridine, ammonia, and CO2 temperature-programmed desorption (TPD). The (1 0 0) facet displayed weaker acid sites with lower site density than the (1 1 1) facet which had a similar density of base sites but those on the (1 0 0) facet were stronger. A strong correlation was observed between 2-propanol conversion and each facet’s acid-base properties. CeO2 cubes exhibited greater base-site catalyzed dehydrogenation to acetone while the more acidic CeO2 octahedra were more active in dehydration to propene.

Photoelectrochemically oxidizing aqueous chloride electrolytes (1 M NaCl, pH 3) to hypochlorous acid proceeds on HxWO3 semiconducting photoelectrodes using 405 nm illumination at 100 mW/cm2 with 1....

Although the relative response of metal oxide chemiresistive gas sensors has been greatly improved by using their nanostructures as sensing units, it remains challenging to recognize the detected gases due to their intrinsic cross-sensing properties. Here, by considering the temperature dependence of the sensing activity for metal oxide gas sensors, the dynamic sensing behavior of CdO (9 at%)-decorated porous ZnO nanobelts as an example was systematically investigated under a continuously changing working temperature. This working temperature modulation was achieved by precisely manipulating high and low heating voltages with a rectangular wave mode. In some working temperature ranges, the fabricated gas sensor exhibited characteristic response curves toward propanol, isopropanol, and ethanol, which were discriminated from other investigated volatile organic compounds (VOCs). Under periodical working temperature modulation, their characteristic response curves were repeatable and stable. In addition, the relationships between the relative responses at characteristic sensing temperature points and their concentrations were investigated. This work offers a promising strategy for using sensing nanomaterials for the highly sensitive recognition and analysis of VOCs, while avoiding cross-sensing.

Perovskites are interesting oxidation catalysts due to their chemical flexibility enabling the tuning of several properties. In this work, we synthesized LaFe1−xCoxO3 catalysts by co-precipitation and thermal decomposition, characterized them thoroughly and studied their 2-propanol oxidation activity under dry and wet conditions to bridge the knowledge gap between gas and liquid phase reactions. Transient tests showed a highly active, unstable low-temperature (LT) reaction channel in conversion profiles and a stable, less-active high-temperature (HT) channel. Cobalt incorporation had a positive effect on the activity. The effect of water was negative on the LT channel, whereas the HT channel activity was boosted for x > 0.15. The boost may originate from a slower deactivation rate of the Co3+ sites under wet conditions and a higher amount of hydroxide species on the surface comparing wet to dry feeds. Water addition resulted in a slower deactivation for Co-rich catalysts and higher activity in the HT channel state.

It is known that mixtures of CTAB and NaSal form viscoelastic solutions. For a 100 mM CTAB solution and increasing NaSal concentration, the viscosity increases strongly at a concentration of 10 mM NaSal, reaches a maximum at 60 mM NaSal, decreases then to a minimum at 100 mM, and, on further, increases passes over a second maximum at a NaSal concentration of 220 mM. The changes of the viscosity at the first maximum, at the minimum, and at the second maximum are due to changes of the mechanism that effect the structural relaxation times while the shear modulus remains constant. On addition of 1-propanol to the solutions at the maximum and at the minimum, the viscosities decrease strongly to the viscosity slightly above water while the shear modulus in the viscous solution remains constant. The data can be explained by assuming that part of the 1-propanol adsorbs at the surface of the three-dimensional network that is formed from wormlike micelles and makes the hydrophobic surface hydrophilic. On addition of 2-propanol to the solutions at the first maximum, the viscosity decreases also at first up to a concentration of 4% 2-propanol. On further increase of 2-propanol, a second relaxation effect with a different relaxation time and a different shear modulus appear. The sum of the two moduli remains about the same as the shear modulus of the solution without isopropanol. The second relaxation effect can be explained by assuming that only one methyl group of 2-propanol binds to the surface of the network while the other one sticks into water. The surface remains therefore hydrophobic and parts of the network can bind to each other what gives rise to the second relaxation effect.

Catalytic hydrogenation of mono-, di- and trinuclear aromatic compounds has been studied under hydrogen transfer conditions at 150 °C and 82 °C in 2-PrOH as a hydrogen donor and with Raney® nickel as a catalyst. In contrast to conjugated or condensed aromatic rings, isolated ones demonstrated low reactivity in transfer hydrogenation (TH) that can be used to increase the hydrogenation selectivity of the reaction. So, naphthalene and biphenyl are partially hydrogenated into tetralin and cyclohexylbenzene, respectively, with excellent conversion (≥ 96 %) and selectivity (≥ 98 %) for 5–6 h at 82 °C. Increasing the reaction temperature to 150 °C results expectedly in the hydrogenation of second aromatic ring, which occurs slowly enough. Only 8 % of decaline and 42 % of dicyclohexyl, correspondingly, were obtained after 5 h at 150 °C. At the same time, TH of trinuclear anthracene and phenanthrene at 150 °C resulted in the formation of deeper hydrogenated octahydro-anthracenes and -phenanthrenes, respectively.

Heterogeneous biocatalysts prepared by immobilizing recombinant lipases are promising for implementation in organic synthesis of various esters used as fragrances, emollients, emulsifiers, non-ionic surfactants, plasticizers, etc. For this research, the Thermomyces lanuginosus lipase produced by the authoring recombinant Pichia pastoris strain was adsorbed on the authoring macroporous carbon aerogel. The prepared biocatalysts were studied in the periodic processes of enzymatic esterification carried out in nonconventional anhydrous media of organic solvents at ambient conditions (22 ± 2 °C, 1 bar). Biocatalytical activities depended strongly on both the selected pair of lipase substrates (acid and alcohol) involved in reaction and the organic solvent used for esterification. The reaction rates of fatty C7 acid esterification with double and triple bond C3 alcohols, such as allyl and propargyl alcohols, were found to be 2–4 times lower than with aliphatic propanol. Isomerism of an acid (not alcohol) molecule greatly affected the esterification rates. It was observed that isomers of C4 and C5 acids (iso-butyric and iso-valeric) practically did not react with butanol. The esterification rates strongly depended on the polarity of the organic solvent characterized by the parameter logP. With an increase in the solvent polarity from non-polar hexane to polar acetone, the esterification rate decreased by two orders of magnitude. The prepared lipase-active biocatalysts had a sufficiently high operational stability under the chosen optimal reaction conditions; their stationary activity (300 ± 100 U·g–1) did not change in periodic reaction cycles during several tens of hours.

The kinetics of oxyethylation of ethanol and propanol-1 was studied under conditions of base catalysis in the absence of a solvent and in solvents (dodecane, para-xylene, and 1,4-dioxane) at ethylene oxide concentrations in the starting mixture of ~1 M and 10–1–10–3 M of sodium alkoxide catalyst (pressure 1.4 MPa, temperature 80–150°С). As in the case of alcohols С4–С7, the results of experiments are adequately described by the first-order kinetic equation based on the concentration of alcohol associates. The association parameters and their temperature dependences were determined. The behavior of the associates in various solvents was studied. It was assumed that the difference between the association parameters of alcohols С2–С3 and those of alcohols С4–С7 lies in the fact that the former are hydrophilic, while the latter are hydrophobic.

In this work, novel bifunctional catalysts based on the polymeric network of hypercrosslinked polystyrene were developed for the process of anthracene hydrocracking in the medium of supercritical propanol-2. The synthesized catalysts contain NiOOH as an active phase and the SiO2 as Bronsted acid sites supported on the highly porous support. The influence of the synthesis method and silica precursor type on the textural properties and the active phase composition was studied. The catalyst obtained by the hydrothermal method using tetraethoxysilane as a silica precursor seems to be the most optimal providing both high surface area, bimodal pore size distribution, and high acidity, and, thus, higher catalytic activity in anthracene hydrocracking.

Lipases (E.C. 3.1.1.3) are biological catalysts widely used in industry due to their versatility, selectivity and specificity. For this reason, the interest in their purification has shown great potential. A technique employed in enzymes recovery capable of preserving their biological activity is partitioning using aqueous two-phase systems. Therefore, the objective of this work was to evaluate the partitioning of lipase extracted from pequi seed in aqueous two-phase systems composed of PEG 4000 or 2-propanol with ammonium sulfate and water at 298 K and 308 K. Lipase partitioning in aqueous two-phase systems was statistically analyzed using the F test and comparison of means test, showing a significant effect (P

The aim of this research is to extract carotenoids from apricot fruits using a food solvent (ethanol) and a non-food solvent (propanol). In addition, it aims to study the effect of different extraction conditions, i.e., the extraction temperature (20-40-60)°C and the extraction times (4-8-12) hours, on the carotenoids yield in order to improve and develop extraction methods. The extracted carotenoids were determined using high-performance liquid chromatography (HPLC), and the studied carotenoids are α-carotene and β-carotene. It was found that β-carotene constitutes about 80% of the total carotenoids in apricots. The results indicated that the extraction yield using ethanol was low compared to the extraction yield using propanol. Propanol is the most suitable solvent for carotenoids extraction in comparison with ethanol. The temperature also had a significant effect on the extraction yield; at 20°C the extraction yield was very low, and 60°C was the optimum temperature for the extraction of carotene. The extraction yield significantly increased with time in the first hours of extraction, and there was no significant effect from increasing the extraction time for a period of 6-8 hours. Moreover, the pretreatment of fruits by freezing accelerated the extraction process and increased the extraction yield. The optimum conditions for extracting carotenoids were determined in the conditions of food extraction; the optimum conditions for extracting carotenoids are: extraction at 60°C for three hours with pretreatment by freezing as the extraction rate reached up to 6.36 mg/100 g using ethanol as a food solvent.

Here, we have designed an efficient multipurpose photocatalytic system based on iron-doped tin oxide (Fe-SnO2) which exhibited excellent catalytic activity toward dyes degradation and hydrogen production. The synthesized photocatalyst was characterized using different spectroscopic techniques. Fe-SnO2 was tested in degradation of different dyes i.e., congo red (CR), acridine orange (ArO) and methyl orange (MO) and among these dyes, Fe-SnO2 was more efficient and selective toward CR which was degraded more than 95% in 30 min. Further, the catalytic efficiency of Fe-SnO2 was also evaluated toward photocatalytic hydrogen generation from aqueous solutions of methanol, ethanol, propanol, potassium hydroxide and Na2S + Na2SO3, where Fe-SnO2 displayed high catalytic activity toward hydrogen generation from methanol solution under sunlight. Moreover, the catalytic activity of Fe-SnO2 toward CR degradation and hydrogen production was optimized by using different combinations of operating conditions and no major loss in activity was observed upon running the same photocatalyst sample in different batches.

Background: Microreactor devices have attracted increasing attention over the last years due to their high surface-to-volume ratio, which ensures a high heat and mass transfer, short molecular diffusion distance and greater spatial illumination homogeneity compared to the traditional reactors. Objective: The aim of this study was to model the kinetics of photo-degradation of 2-propanol over TiO2-based thin films in a gas-phase batch-reactor and simulate their performance in a microreactor device. Methods: The reaction was carried out in a gas-phase batch-reactor, assessing the reactivity of singlelayer nitrogen (N)-doped TiO2 and a bilayer consisting of N-doped TiO2 as a bottom layer and copper (Cu)-doped TiO2 as a top layer. The kinetics of the photocatalytic process was modelled by Langmuir– Hinshelwood (LH) model. The constants obtained from the LH model were used to simulate the performance of the photocatalysts in a microreactor, operating in a continuous flow mode and investigating the effect of the volumetric flow rate (Q), initial concentration of pollutant (Co), number of microchannels (n) and microchannel length (l) on the photo-degradation of 2-propanol. Results: N-Cu-TiO2 exhibited a higher reactivity but a lower adsorption ability towards the target pollutant compared to N-TiO2. To maximize and leverage the advantages of a microreactor, optimal operating conditions for a continuous flow mode, at a steady-state, should be moderately low Q and Co, long l and n that minimizes flow maldistribution in parallel. Conclusion: The findings in this work could serve as a basis to design and fabricate efficient microreactors for the removal of VOC in air purification applications.

A handheld refractometer (HHR) is a versatile instrument in the chemistry lab or in the workplace. It is also inexpensive enough (

The Cl/OH initiated temperature dependent photo-oxidative reaction kinetics of methyl butyrate (MB) were examined using a relative rate (RR) technique. Gas chromatography with flame ionization and mass spectrometric detection were used to monitor the concentration of the reactants and to identify the products. The temperature dependent kinetics of MB with Cl atoms were measured with respect to the reaction of Cl with C2H 6 and C2H4. The temperature dependent kinetics for the reaction of MB with OH radicals were measured using n- propanol and iso -propanol as references. The obtained rate coefficients for the Cl and OH reactions with MB are, k Cl(Expt) (T) = [(7.76 ± 0.47) × 10 −11] exp [(10.31 ± 0.20)/T] cm3 molecule−1 s−1 and k OH(Expt) (T) = [(4.32 ± 0.21) × 10 −12] exp [-(25.26 ± 0.39)/T] cm3 molecule−1 s−1 respectively. Dual level direct dynamics were used to perform the computational calculations to further elucidate the mechanisms over the studied temperature range. The rate coefficients for H-abstraction reactions were computed using Canonical Variational Transition State Theory with Small Curvature Tunneling (CVT/SCT) with Interpolated Single Point Energies (ISPE) method. The rate coefficients over the studied temperature range yielded the Arrhenius equations: k Cl(Theory) (200–400 K) = [(4.05 ± 0.54) × 10–11] exp [-(2.80 ± 0.11)/T] cm3 molecule−1 s−1 and k OH(Theory) (200–400 K) = [(1.96 ± 0.68) × 10 -11] exp [-(384 ± 38)/T] cm3 molecule −1 s −1. Possible degradation mechanisms for the reactions are proposed based on the observed products. Thermo-chemical parameters, ozone formation potential, branching ratios, and the atmospheric lifetime of MB are calculated to understand the fate of MB in the atmosphere.

WOx-promoted TiO2–ZrO2 solid acid catalyst was prepared and applied in the catalytic acetalization and ketalization of glycerol with carbonyl compounds to produce biofuel additives. The presence of WOx promoter and TiO2 remarkably improved the catalytic activity of ZrO2. Approximately, 100% glycerol conversion was evidenced with non-bulky aliphatic aldehydes and ketones like, propanol and cyclohexanone. The physical characterization of WOx-promoted TiO2–ZrO2, revealed a higher formation of tetragonal crystalline phase of ZrO2, over monoclinic. The total surface acidity and the ratio of Bronsted to Lewis acidic site concentrations were determined by NH3-TPD and pyridine-chemisorbed FTIR spectroscopy, respectively. A considerably higher concentration of Lewis acidic sites, ~ 213.29 μmol/gm, was evidenced on the WOx-promoted TiO2–ZrO2 catalyst surface. Catalytic activity study revealed a direct correlation between the surface Lewis acidic site concentration and the activity of catalyst. This significant observation indicated the key role of Lewis acidic sites in this catalytic process. The WOx-promoted TiO2–ZrO2 catalyst was also considerably stable and showed good performance in the acetalization/ketalization of glycerol with other substituted carbonyl compounds. The WOx-promoted TiO2–ZrO2 solid acid catalyst exhibits superior catalytic performance for acetalization and ketalization of glycerol with carbonyl compounds to produce biofuel additives.

To determine the primary contributor to neurotoxicity in patients with glufosinate ammonium (GLA) poisoning, by quantifying glufosinate, 1-methoxy-2-propanol, and ammonia in serum and the cerebrospinal fluid (CSF). We collected and analysed data from confirmed cases of GLA poisoning between May 2018 and August 2020. Based on the occurrence of neurological complications (mental change, seizure, and central apnoea), patients were assigned to one of two groups: those with complications (NCx) and without (non-NCx) complications. Concentrations of glufosinate, 1-methoxy-2-propanol (1M2P), and ammonia were measured in the serum upon admission and during hospital stay. The concentrations of all these substances were again measured in the CSF following a decline in the mental status or seizure (NCx group) or on the day after hospitalisation (non-NCx group). Of the 20 patients included, ammonia levels in the serum and CSF at onset of altered sensorium in the NCx group (n = 16) were significantly higher than those at one day after hospitalisation in the non-NCx group (n = 4) (p = 0.011 in serum, p = 0.047 in CSF), with its concentration in the CSF being higher than that in the serum in 15/16 cases. The concentration of 1M2P was similar in the serum and CSF (8/16), but the concentrations of glufosinate (7/16) was lower in the CSF than in the serum. In the non-NCx group (n = 4), only ammonia was detectable. Among patients with GLA poisoning, increased CSF ammonia was significantly correlated with neurological complications.

Introduction. The microbial biofilm-forming ability is one of the major aspects of the emerging issue of antibiotic resistance, which makes them tolerant to antibiotics and host defense systems and other external stresses, thus contributing to persistent chronic infections. A series of relevant studies confirmed the high efficiency of aminopropanol derivatives as potential antibacterial and antifungal agents. This present study was aimed to evaluate the antimicrobial activity of new 1-[(2,4-(di-tert-butylphenoxy))-3-dialkylamino-2-propanol] derivatives on the planktonic bacterial/fungal cells and biofilms. Material and methods. The minimum inhibitory concentrations (MIC) of the new compounds were determined by a standard method, along with their effects on biofilms estimated via the gentian violet adsorption-desorption assay.Results. The КVM-219 compound showed the most pronounced effect on planktonic bacterial and fungal cells. The MIC values ranged between 0.78 μg/mL to 12.5 μg/mL, depending on the microbial strain. The KVM-316 compound exhibited the strongest inhibitory effect on biofilms, thus preventing their formation by S. aureus (96.1%), E. coli (57.2%), and P. aeruginosa (96.1%). Conclusions. The 15 newly synthesized 1-[(2,4-(di-tert-butylphenoxy))-3-dialkylamino-2-propanol] derivatives revealed marked antibacterial and antifungal effects on planktonic microorganisms. Most of these compounds showed a strain-specific inhibition of biofilm formation by at least 50% for S. aureus 222, E. coli 311, P. aeruginosa 449 and C. glabrata 404 strains.

α-Site alcohol radicals are the most important products of H-abstract reactions from alcohols since the hydroxyl moiety weakens the α-site C-H bond. Reactions between α-site alcohol radicals and O2 play an important role in combustion of alcohols, especially at relatively low temperatures. However, reliable reaction pathways and rate constants for these reactions are still lacking. Theoretical studies on reactions in α-hydroxyethyl radical (CH3C•HOH) + O2 and α-hydroxypropyl radical (C2H5C•HOH and CH3C•OHCH3) + O2 reaction systems are performed in this work. Pressure-dependent rate constants for the involved reactions in a wide range of temperatures are determined using the Rice-Ramsperger-Kassel-Marcus/master equation (RRKM/ME) method. Our results show that rate constants for reactions in the α-hydroxypropyl radical + O2 system are quite different from those in the CH3C•HOH + O2 system. Detailed reaction pathways for these reaction systems are clarified, although combustion characteristics of ethanol and propanol do not change much with the obtained rate constants for these reactions. Important reaction channels in producing enols, especially in the combustion of propanol, are also provided. The obtained rate constants for these reactions over a wide range of temperatures and pressures are helpful in developing combustion mechanisms for ethanol and propanol.

Abundant alcohols, including ethanol, propanol, butanol, and pentanol, are expected to be used in compression ignition engines to ease the shortages of fossil fuel. The various alcohols have quite a different combustion and emission characteristics in the engine due to the changes in molecular structures. In this paper, a series of experiments were conducted on a modified common-rail diesel engine fueled with diesel/alcohols blended fuels in a wide operating range. The effects of alcohol chain length, oxygen content, and molecular structure on engine combustion and emission characteristics are studied systematically. The experimental results show that the blending of alcohols increases the peak values of in-cylinder pressure and maximum pressure rising rate. Besides, the combustion duration and ignition delay are mainly affected by oxygen content and isomer structure. The addition of short-chain alcohols will significantly reduce the total mass of particulate matter (PM) emissions, while the CO and HC emissions increase appropriately. The CO, HC, aldehydes, and ethylene emissions are mainly affected by carbon chain length and isomer structure. For PM emissions, the carbon chain length, molecular structure, and oxygen content of alcohol fuels have different influences on PM number, PM mass, and particle size distributions. The shorter carbon chain of alcohol leads to smaller particle size, and higher oxygen content leads to lower total particle mass.

The influence of replacing water with ethanol, propanol, and butanol in alcohol–water mixtures on the rheological properties of wormlike micelles (WLMs) consisting of sodium salicylate (NaSal) and cetyltrimethylammonium bromide (CTAB) is investigated at 25 °C. At maximum viscosity of 100 mM CTAB and 60 mM NaSal, the alcohols at low concentrations of up to 8% ethanol, 3% propanol, and 2% butanol do not affect the WLM structure as indicated by the normal modulus values of the solutions, but they decrease the structural relaxation times and their viscosities. This behavior is explained by the fact that as alcohol chain length increases, it has lower miscibility in water, and hence, it can interact to a higher extent with WLMs even at lower contents. We hypothesize that alcohols adsorbed at the WLM surface make it more hydrophilic. The contacts between WLMs are therefore lost, the viscosity decreases, and the structural relaxation times become faster. At suitable contents, alcohol molecules can penetrate WLMs and damage their structure. For solutions with minimum viscosity, higher alcohol contents were required to destroy WLMs, and replacing water with ethanol leads to viscosity increase, followed by a gradual decrease at higher ethanol contents. Propanol and butanol drastically changed the WLM viscoelastic properties. Generally, as the alcohol chain length increases, WLMs become more pronounced at lower alcohol contents. Alcohols, at relatively low amounts, do not affect the WLM structure but lead to vanishing of the entanglement between WLMs. Butanol, due to its longer chain compared to ethanol and propanol, destroys WLMs at lower contents. Generally, as alcohol chain length increases, the damage of entanglement between WLMs becomes more pronounced at lower alcohol contents.

Density functional theory (DFT) simulations are conducted to understand the differentiation of activity and selectivity trends between primary and secondary alcohols towards the non-oxidative dehydrogenation (NODH) reaction. Propanol and isopropanol are employed as model molecules to explore the NODH on the (111) facets of Cu. The initial dehydrogenation of propanol via the hydroxyl route exhibits a higher barrier (96.8 kJ/mol) as compared to that of isopropanol (61.4 kJ/mol). Furthermore, the second dehydrogenation step resulting in the formation of the carbonyl compound is also calculated to show higher barrier of primary alcohol (83 kJ/mol) than secondary alcohol (51.3 kJ/mol). Overall, for the consecutive dehydrogenation steps, propanol is observed to show higher activation barriers as opposed to that of isopropanol, indicating towards a higher conversion rate for isopropanol, similar to the trend observed experimentally. However, the subsequent dehydrogenation of the carbonyl compound formed shows a barrier of 112.8 kJ/mol for acetone and that of 70.6 kJ/mol for acetaldehyde owing to the higher stability of ketone. The formation of ester from the propionyl produced upon acetaldehyde dehydrogenation is calculated to show the lowest barrier (64.6 kJ/mol) amongst the dehydrogenation steps of primary alcohol dehydrogenation route, suggesting towards lower selectivity in case of NODH of propanol.

Dielectric properties (permittivity and loss tangent) of various liquids (water, methanol, propanol, acetone, and isopropanol) are determined by analyzing the frequency detuning effects of different millimeter-wave resonators exposed by the liquid-under-test. Alumina ceramic spherical dielectric resonators, fed from a thin-film circuit, form a resonator fixture operating at 190 GHz. Subnanoliter amount of liquid, carried in a glass tube, is exposed to the resonator. Analysis of the setup by means of electromagnetic field simulations reveals the liquid’s dielectric properties. Extracted data match well with properties obtained from Debye models. Measurement sensitivity is discussed with respect to frequency shift, sensed volume, and dielectric contrast. Obtained sensitivity figure-of-merit outperforms alternative techniques at such high frequency.

High concentrations of hydrocarbons were found in ground (400–4560 mg/kg) and bottom sediments (1180–17640 mg/kg) of the industrial zone of Khabarovsk. Intense microbiological transformation of organic pollutants was confirmed by the predominance of microbial components in alkanes, by the composition of volatile organic compounds (methanol, propanol, acetaldehyde, etc.), and by the total number of heterotrophic bacteria (27‒47 million CFU/g in ground and 180 million CFU/g in bottom sediment). The contribution of carbon of chlorophyll “a” to the total organic carbon in bottom sediments (3.6–9.5%, on average 6.2%) was two times higher than in ground.

Solubility and density profiles for 3-aminosalicylic acid (3-ASA) in the mixed solvents of 2-propanol and water is determined by a shake-flask method at 293.2–313.2 K. The obtained numerical data i...

The present work provides thermophysical data on binary mixtures of titanium(IV) isopropoxide (TTIP) and 2-propanol (iPOH), which are important precursor solutions in spray flame synthesis of nanoparticles. The specific density, viscosity, thermal conductivity, and molar isobaric heat capacity were measured at 101.3 kPa and temperatures ranging from 293.15 to 333.15 K. The vapor–liquid equilibrium (VLE) was measured at pressures ranging from 20 to 80 kPa. Furthermore, self-diffusion coefficients of pure iPOH were measured at 101.3 kPa and temperatures ranging from 293.15 to 333.15 K. A qualitative study using 1H NMR spectroscopy provides evidence for a cross-association between TTIP and iPOH in the mixture. Correlations for all studied thermophysical properties are provided. The results establish a rational basis for the design of spray flame synthesis processes.

In this paper, we report the construction and characterization of a sensor to detect volatile organic compounds, particularly alcohols. The sensor was fabricated by depositing a polydimethylsiloxane sensing film on the surface of a long-period fiber grating (LPFG). The LPFG spectrum, which was taken as the sensor response, was measured in a Teflon chamber, where different concentrations of methanol, ethanol, propanol, and butanol samples were injected. Spectral shifts to lower wavelength were observed for the last three samples. However, a shift to higher wavelengths for the case of methanol was observed, which was attributed to the fact that its refractive index is smaller than the one for PDMS. Therefore, curves of the sensor response in function of concentration were performed using different analysis techniques: analysis in a fixed wavelength, analysis in a fixed spectrum amplitude and spectral analysis trough principal components analysis (PCA) method. The results showed a regular behavior of the responses according to the molecular weight of the samples. A discussion of the use of each technique was performed.

Carbonyl C═O bond reduction via catalytic transfer hydrogenation (CTH) is one of the essential processes for biomass conversion to valuable chemicals and fuels. Here, we investigate the CTH of furf...

Ion mobility spectrometry (IMS) and mass spectrometry (MS) techniques were used to monitor diketopiperazine (DKP) formation from the peptide FPG8K at multiple defined temperatures in methanol, ethanol, propanol, and water, with the motivation to study the effect of solvent polarity on spontaneous solution dissociation. The reaction rate increases with decreasing solvent polarity. The observed rates of trans → cis isomerization of Phe1-Pro2 and the cis-Pro2 isomer dissociation result in the cis isomer growing in abundance relative to the trans isomer throughout the reaction in all solvents. Analysis of rate constants derived from the data using a sequential unimolecular kinetics model that includes hidden intermediate states yields transition state thermodynamic values for both trans → cis isomerization of Phe1-Pro2 and dissociation. The measured thermochemistry appears to be closely correlated with these solvents' dielectric constants: a lower solvent dielectric constant accelerates the reaction by reducing the enthalpic barrier, albeit with slight entropic restriction.

Two component mixtures, 3-methoxy-3-methyl-1-butanol (MMB)+carbon dioxide and 1-methoxy-2-methyl-2-propanol (MMP)+carbon dioxide, were investigated at 313.2, 333.2, 353.2, 373.2 and 393.2 K and at 4.29 to 20.95 MPa to get phase equilibrium data. The phase separation of vapor+liquid behavior for the MMB and MMP plays a momentous function as the organic solvent in a diversity of industrial processes. The two MMB+carbon dioxide and MMP+carbon dioxide components have mixture critical curves that have maxima in the p-T plot between the Tc (critical temperatures) of MMB and carbon dioxide or MMP and carbon dioxide. The two component systems of MMB+ carbon dioxide and MMP+carbon dioxide mixture display type-I in simplest behavior. The measured results for the two component mixtures, MMB+carbon dioxide and MMP+carbon dioxide, are modelled with a general cubic equation of state, the Peng-Robinson, containing the kij, ηij adjustable factor.

Electrochemical CO2 reduction can produce valuable products with high energy densities but the process is plagued by poor selectivities and low yields. Propanol represents a challenging product to obtain due to the complicated C3 forming mechanism that requires both stabilization of *C2 intermediates and subsequent C1–C2 coupling. Herein, density function theory calculations revealed that double sulfur vacancies formed on hexagonal copper sulfide can feature as efficient electrocatalytic centers for stabilizing both CO* and OCCO* dimer, and further CO–OCCO coupling to form C3 species, which cannot be realized on CuS with single or no sulfur vacancies. The double sulfur vacancies were then experimentally synthesized by an electrochemical lithium tuning strategy, during which the density of sulfur vacancies was well-tuned by the charge/discharge cycle number. The double sulfur vacancy-rich CuS catalyst exhibited a Faradaic efficiency toward n-propanol of 15.4 ± 1% at −1.05 V versus reversible hydrogen electrode in H-cells, and a high partial current density of 9.9 mA cm−2 at −0.85 V in flow-cells, comparable to the best reported electrochemical CO2 reduction toward n-propanol. Our work suggests an attractive approach to create anion vacancy pairs as catalytic centers for multi-carbon-products. Electrochemical CO2 reduction to the valuable n-propanol is challenging due to the complicated C3 forming mechanism. Here, authors demonstrate double sulfur vacancies formed on hexagonal copper sulfide can serve as efficient electrocatalytic centers.

Due to the importance of producing clean energy through systems such as alcoholic fuel cell, methanol, ethanol, 1-propanol, and 2-propanol, these alcohols were oxidized at the modified graphite electrode by NiTPPBr6 / NiTPPBr8 as a clean electrocatalyst in an alkaline media. This process investigated by various techniques such as cyclic voltammetry (CV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS), in all cases showed Cottrell type behavior with the diffusion of coefficients of 2.04 × 10[Formula: see text], 1.3 × 10[Formula: see text] 8.3 × 10[Formula: see text] cm[Formula: see text] s[Formula: see text] for the corresponding alcohols respectively. Likewise, the catalytic rate constant for methanol oxidation was found to be 2.9 × 108 cm3mol[Formula: see text] s[Formula: see text] through chronoamperometric measurements. Interestingly, the order in activity for oxidation of the alcohols introduced with the electrocatalyst was: 2-propanol [Formula: see text] 1-propanol [Formula: see text] ethanol [Formula: see text] methanol and was unlike previous studies in which the oxidation current was reduced by increasing the number of carbon atoms from methanol to propanol.

A thermal process was employed to prepare a catalyst consisting of a mixture of metallic-Pt and rutile RuO2 nanocrystals. This catalyst was used for the electrooxidation of 2-propanol in an alkaline solution. The effect of the catalyst composition on its microstructure, surface properties and catalytic activity was examined. With increasing the RuO2 content, the catalytic activity increases, reaches its maximum and then decreases. The catalytic effect is a result of the bifunctional mechanism of the mixture of Pt and RuO2 nanocrystals. The RuOHad particles are formed on Ru atoms of the RuO2 nanocrystals at potentials more negative than on Pt atoms. These oxy-species facilitate the dehydrogenation, breaking of C–C bonds and oxidation of both 2-propanol and its intermediates, adsorbed on assemblies of adjacent Pt atoms.