Isopropanol Research Articles

Purification of Glucomannan from Porang (Amorphophallus oncophyllus) Tuber Flour through Hydrolysis of Hydrochloric Acid

Porang (Amorphophallus oncophyllus) is a local perennial plant that commonly grown in Indonesian forest. Its tuber contains a lot of glucomannan that has many benefits as food ingredient or as functional food. Glucomannan has a lot of health benefits, such as anti-diabetic effect, low glycemic index, prebiotic effect, etc. Despite that, the extraction is still a problem because it is difficult to get pure glucomannan extract out of Porang flour. Thus, in this study we are going to use hydrocloric acid to extract the glucomannan from the porang flour through hydrolysis extraction. This research will test the effect of hydrochloric acid concentration on the purity of glucomannan extract obtained from porang flour, to study the effect of nonsolvent, ethanol and isopropyl alcohol on glucomannan concentration, and to obtain the optimal condition to get high concentration of glucomannan using extraction with pretreatment hydrochloric acid hydrolysis.

Dielectric relaxation study of pyridine-n-propyl alcohol mixture using time domain reflectometry technique

ABSTRACT The Time Domain Reflectometry (TDR) technique was used to analyse the complex permittivity spectra of the Pyridine-n-propyl alcohol mixture across the concentration and temperature range of 10–25°C. The Cole-Davidson model was used to match the Pyridine- n-propyl alcohol complex permittivity spectra. The nonlinear least squares fit approach has been used to obtain the Static dielectric constant (ε0), Relaxation time (τ), Effective Kirkwood correlation factor (geff) Excess permittivity ε 0 E , Thermodynamic parameters (activation enthalpy and activation entropy), and Bruggeman factor (fB). Furthermore, the analysis of excess characteristics and the Bruggeman factor points towards the presence of hydrogen bonding between the pyridine and n-propyl alcohol molecules.

Rhodium-Catalyzed Functionalization and Annulation of N-Aryl Phthalazinediones with Allyl Alcohols.

A direct ortho-Csp2-H acylalkylation of 2-aryl-2,3-dihydrophthalazine-1,4-diones with unsubstituted and substituted allyl alcohols is achieved in high yields through Rh(III)-catalyzed C-H bond activation process. The additional employment of Cu(OAc)2⋅2H2O as an oxidant detour the reaction towards [4+1] annulation, producing 13-(2-oxopropyl)-13H-indazolo[1,2-b]phthalazine-6,11-diones in moderate yields. Interestingly, Lawesson's reagent-mediated conditions accomplished intramolecular cyclization in ortho-(formylalkylated)-2,3-dihydrophthalazine-1,4-diones to produce diazepino[1,2-b]phthalazine-diones in moderate yields. Furthermore, allyl alcohol showcased distinct reactivity in presence of different additives to produce ortho-allylated, oxidative and non-oxidative [4+2] annulated products.

A Universal Ternary Solvent System of Surface Passivator Enables Perovskite Solar Cells with Efficiency Exceeding 26.

Surface passivation is a vital approach to improve the photovoltaic performance of perovskite solar cells (PSCs), in which the passivator solvent is an inevitable but easy-ignored factor on passivation effects. Herein, a universal ternary solvent system of surface passivators is proposed through comprehensively considering the solubility and selective perovskite dissolution of the solvent to maximize the passivation effect. Tetrahydrothiophene 1-oxide (THTO) is selected as the passivation promoter by comparing the binding energy with perovskite and the ability to distort the perovskite lattice among various aprotic polar solvent molecules, which can facilitate the passivator's reaction with perovskite and achieve sufficient passivation on perovskite surface. Besides, chlorobenzene (CB) is used as the diluting agent to minimize the amount of isopropanol (IPA), inhibiting the additional solvent-induced defects. As a result, the planar PSCs achieve a power conversion efficiency (PCE) of 26.05%, (certificated 25.66%). Besides, the unencapsulated devices exhibit enhanced stability, which can maintain 95.23% and 95.68% of their initial PCE after 2000h of storage in ambient air and 800h of light-soaking in N2-glovebox. Moreover, this ternary solvent system also exhibits a well applicability and reliability in different passivator such as PEAI, BAI, and so on.

Kinetic investigation on palladium‐catalyzed carbonylation of allyl alcohol

AbstractPalladium‐catalyzed carbonylation of allyl alcohol to 3‐butenoic acid has been investigated. A significant effect of halide promoters, p‐tolylsulfonic acid (TsOH), water, solvents, and PPh3 concentration activity and selectivity has been studied. Detailed kinetics of this reaction was investigated in a temperature range of 363–383 K. The influence of parameters such as stirring speed, allyl alcohol, catalyst, benzyltriethylammonium chloride (BTEAC), TsOH concentrations, and CO partial pressures on the activity and selectivity has been studied. An empirical rate equation was suggested and found to be fairly consistent with observed rate data. In addition, the activation energy and kinetic parameters were evaluated.

Reaction kinetics for catalytic hydrogenation of quinoline to decahydroquinoline as liquid organic hydrogen carrier

The catalytic hydrogenation of quinoline to decahydroquinoline (DHQ) formation is studied for various parameters such as temperature, hydrogen pressure, reaction time, solvents, reactant-to-solvent ratio, and catalyst loading over 5%Pd loaded on alumina (Pd/Al2O3) to obtain optimal reaction conditions. The hydrogen uptake of quinoline in the liquid phase reaction using isopropylalcohol (IPA) is studied in an autoclave reactor. The optimum reaction parameters of 50 bar H2 pressure and 175oC with reactant to solvent ratio of 1:9 for reaction time of 5 h are observed. The effect of IPA solvent showed that hydrogen uptake of 6.91 wt% with complete hydrogenation of quinoline and DHQ yield of more than 99% is observed. The reaction kinetic model is developed for a simplified reaction mechanism and is simulated using the Markov Chain Monte Carlo (MCMC) simulation tool to predict the rate constants and the experimental observations are validated with the model predictions. The activation energy for quinoline hydrogenation to py-THQ formation is estimated to be 136.57 kJ/mol. It is envisaged that quinoline hydrogenation to pz-THQ is the rate-limiting step in the DHQ formation.

Synthesis of tin selenide nanoparticles using Polygonum avicular extract decorated on graphitic carbon nitride for enhancing photodegradation of amoxicillin trihydrate and photoproduction of hydrogen peroxide

In this research, tin selenide nanoparticles (SnSe-NPs) were synthesized using Polygonum avicular extract via the hydrothermal method and decorated on graphitic carbon nitride (g-C3N4) by the simple sonicated method to produce SnSe/g-C3N4 composites. The characterization and properties of the SnSe/g-C3N4 composites, as compared to pristine SnSe and g-C3N4, were determined by Fourier-transform infrared spectroscopy, X-ray powder diffraction, scanning electron microscope, transmission electron microscopy, field emission scanning electron microscopy, X-ray photoelectron spectroscopy, ultraviolet–visible diffuse reflectance spectroscopy, Mott-Schottky, and electrochemical impedance spectroscopy. As a result, the SnSe-NPs possessed the rod-like shape and after the decoration onto the g-C3N4 sheet surface, it reduced the bandgap energy of the g-C3N4 from 2.58 downward 1.43 eV. Besides, the photoactivities of the 10-SnSe/g-C3N4 catalyst were investigated via both sides of amoxicillin trihydrate (AMXT) photodegradation and hydrogen peroxide (H2O2) photoproduction, in which the results were achieved 87.84 % AMXT and 85.48 μM H2O2, respectively, under visible light. Furthermore, the photodegradation was consistent with the pseudo-first-order kinetics and it performed the highest photodegradation at pH ∼5, while the importance of isopropyl alcohol as a trapping agent and •O2− radicals was affirmed in the H2O2 photoproduction. Moreover, the photoproduction of H2O2 was remained after 4 cycles achieved at 62.70 % in the final cycle, which demonstrated the stability and reusability of the 10-SnSe/g-C3N4. These aforementioned results demonstrate that the SnSe/g-C3N4 material is a promising candidate for addressing environmental pollution and energy scarcity issues.

Influence of WO3 Content in Phosphated Tungsten-Zirconium Oxide Catalysts on the Catalytic Pathways of Glycerol Transformation.

The catalytic performance of phosphate-stabilized WOx-ZrO2 compositions in gas-phase glycerol dehydration has been investigated. Results show that varying WO3 concentrations direct the process towards either acrolein or allyl alcohol formation. Catalysts with low WOx content exhibit strong Lewis acid sites (Zr4+ and W6+), where these metal ions likely function as redox sites, facilitating glycerol hydrogenolysis to produce allyl alcohol. Higher WO3 concentrations (exceeding 20 wt.%) lead to the shielding of some W6+ and Zr4+ sites by polytungstate surface complexes, which are strong Brønsted acid sites. This alteration promotes glycerol dehydration through the removal of two water molecules, thereby shifting the selectivity towards acrolein formation.

Ruthenium-Catalyzed Synthesis of 2-Pyrazolines via Acceptorless Dehydrogenative Coupling of Allylic Alcohols with Hydrazines.

Described herein is the synthesis of 2-pyrazolines via acceptorless dehydrogenative coupling of allylic alcohols with hydrazines based on a Ru3(CO)12/NHC-phosphine-phosphine ligand L catalytic system. The reaction not only exhibits low catalyst loading (only 0.3 mol %), wide substrate scope, good to excellent yields, and high selectivity but also omits the use of sacrificial hydrogen acceptor with only H2 and H2O as byproducts, making the reaction green and atom-economical.

Enantioselective Synthesis of Axially Chiral Allylic Nitriles via Nickel-Catalyzed Desymmetric Cyanation of Biaryl Diallylic Alcohols.

Axially chiral nitriles are common motifs in organic photoelectric materials, biological compounds, and agrochemicals. Unfortunately, the limited synthetic approaches to axially chiral nitriles have impeded their availability. Herein, we report the first nickel-catalyzed desymmetric allylic cyanation of biaryl allylic alcohols for the synthesis of axially chiral nitrile structures in high yields with excellent enantioselectivities (up to 90% yield and >99% ee). This process enables the synthesis of a diverse range of axially chiral allylic nitriles bearing β,γ-unsaturated alcohol moieties. Leveraging the allylic alcohol and cyano groups as versatile functionalization handles allow for further derivatization of these axially chiral frameworks. Density functional theory (DFT) calculations suggest that both steric and electronic interactions play crucial roles in determining the enantioselectivity of this transformation. Moreover, this mild and facile protocol is also applicable for gram-scale preparation of the chiral nitriles.

Enantioselective Synthesis of Axially Chiral Allylic Nitriles via Nickel‐Catalyzed Desymmetric Cyanation of Biaryl Diallylic Alcohols

Axially chiral nitriles are common motifs in organic photoelectric materials, biological compounds, and agrochemicals. Unfortunately, the limited synthetic approaches to axially chiral nitriles have impeded their availability. Herein, we report the first nickel‐catalyzed desymmetric allylic cyanation of biaryl allylic alcohols for the synthesis of axially chiral nitrile structures in high yields with excellent enantioselectivities (up to 90% yield and >99% ee). This process enables the synthesis of a diverse range of axially chiral allylic nitriles bearing β,γ‐unsaturated alcohol moieties. Leveraging the allylic alcohol and cyano groups as versatile functionalization handles allow for further derivatization of these axially chiral frameworks. Density functional theory (DFT) calculations suggest that both steric and electronic interactions play crucial roles in determining the enantioselectivity of this transformation. Moreover, this mild and facile protocol is also applicable for gram‐scale preparation of the chiral nitriles.

Morphology and elemental composition of titanium powders for additive machines obtained by electrospark dispersion of OT4 alloy metal waste in propyl alcohol

Morphology and elemental composition of titanium powders for additive machines obtained by electrospark dispersion of OT4 alloy metal waste in propyl alcohol

PTFE layer formation during brush electroplating of nickel

Brush electrodeposition of Ni/PTFE composite coatings was explored using a nickel high speed solution and polytetrafluoroethylene (PTFE) particles 6–9 μm in diameter. A novel bilayer-like, partially intercalated structure was produced, consisting of a rough nickel sublayer covered by an outer, compact, smooth PTFE layer. The study of the coating growth revealed that the PTFE particles bind together on the nickel coating valleys and grow until all the surface is covered by a polymer layer without the need of a baking stage. The resulting coating presents a hydrophobic surface with a low coefficient of friction (0.10) and higher corrosion resistance to salt spray testing than the nodular nickel coating. The coatings were produced using an aqueous nickel plating solution, where the hydrophobic PTFE particles were suspended using different substances: cetrimonium bromide (CTAB) cationic surfactant, isopropyl alcohol premixed with the particles, and ethanol premixed with the particles. High concentrations of the suspending products were detrimental for the deposition process, but optimal values of 0.1 g/l, 3 ml/l and 3 ml/l respectively were found. All compounds successfully suspended the PTFE particles and both alcohols produced the Ni/PTFE coating described before, but the CTAB failed to co-deposit the polymer.

Preparation and performance evaluation of CNF‐enhanced polyether‐modified polysiloxane defoamer

AbstractIn this article, polyether‐modified polysiloxanes were synthesized by the reaction of poly(methyl hydrogen siloxane) (PMHS) with Allyl alcohol polyether B‐400. FT‐IR, laser particle size analysis, hydrophilic–lipophilic balance (HLB) value test, and surface tension measurements were used to characterize its structures and properties. The results show that the control law for the HLB value of polyether‐modified polysiloxanes was obtained as follow: the HLB value increases with increasing hydrogen content of PMHS. When the polyether‐modified polysiloxanes were used to emulsify the polysiloxane, at the HLB value of 10.5, the average particle size of the emulsion was about 0.23 μm with a narrow particle size distribution. The emulsion has good emulsifying and dispersing properties, as well as excellent foam elimination and foam inhibition performance. When the cellulose nanofibrils (CNF) was used as a protective agent for the preparing of the polysiloxane defoamer, the stability of the emulsion does not affect, but its foam elimination and foam inhibition of emulsion can be further improved at the presence of CNF. The lowest surface tension of CNF‐enhanced polyether‐modified polysiloxane defoamer is about 22.4 mN m−1, which has good surface property. When the concentration of CNF‐enhanced polyether‐modified polysiloxane defoamer was 0.1 g L−1, the foam elimination time and foam inhibition time were 5.8 s and 38 min, respectively, at the temperature (80°C) and alkali environment (pH 13).

Energy-efficient heat pump-assisted pre-concentration integrated with sequential [EMIM][BF4] and ethylene glycol-based extractive distillation for enhanced recovery of ethanol and isopropyl alcohol from wastewater

Recovering ethanol and isopropyl alcohol (IPA) from wastewater offers significant economic and environmental advantages. In this work, 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF4]) and ethylene glycol (EG) are proposed as double entrainers for separating IPA/ethanol/water mixtures. The novel process sequentially uses [EMIM][BF4] to separate ethanol/water and IPA/water azeotropes, followed by EG for near-boiling mixture of ethanol/IPA. Energy-economic comparisons of extractive distillation process using single and double entrainers are performed. To address the issue of high water content in mixtures, the heat pump-assisted pre-concentration (HPP) integrated with extractive distillation processes are proposed. Subsequently, the effect of water content in the mixtures on process performances are analyzed. The results indicate that compared to using a single entrainer [EMIM][BF4] or EG process, the double entrainers process reduces energy cost and total annual cost (TAC) by 19.9% to 45.3% and 18.6% to 52.7%, respectively. The HPP scheme effectively reduces the mole fraction of water from 60% to 26.05%, further decreasing energy costs by 4.2% to 22.2%. The energy cost and TAC of the double entrainers process decreases by 4.8% to 50%, and 2.8% to 52.1% compared with the single entrainer process under HPP schemes. The double entrainers [EMIM][BF4]-EG process shows promising prospects from energy and economic perspectives.

Ni(II)-catalyzed asymmetric alkenylation and arylation of aryl ketones with organoborons via 1,5-metalate shift

Chiral tertiary alcohols are an important structural motif, however, the general and efficient methodologies for their synthesis are less reported. Herein, we report a Ni(ІІ)-catalyzed asymmetric alkenylation and arylation of aryl ketones with organoborons under air via a 1,5-metalate shift strategy to obtain chiral tertiary allylic alcohols and diaryl alcohols. The reaction demonstrates good functional group tolerance and delivers chiral tertiary alcohols with good to excellent results. Furthermore, this method can be applied to the late-stage modification of drugs and the efficient synthesis of natural products. Notably, the reaction proceeds through an outer-sphere mechanism. The Ni(II) complex functions both as a Lewis acid to activate the ketone and create a chiral environment, and as coordination bridge linking the ketone and the organoboron-derived “ate” complex, facilitating the 1,5-metalate shift without forming a C-Ni bond. This approach contrasts with traditional transition metal-catalyzed nucleophilic addition reactions that involve carbon-metal bond formation.

Roles of modified additives in the repair of damaged SiC-ZrB2/SiC coating of carbon/carbon composites

Damaged SiC-ZrB2/SiC (SZS) coatings of carbon/carbon (C/C) composites were repaired using polysiloxane (PSO)-based repair agents. SiC-ZrB2 powder was used as an inert filler, and Al2O3 and isopropyl alcohol (IPA) were introduced as modified additives. The effects of each component of the repair agents on the chemical composition, microstructure, and oxidation behavior of the repaired coatings were investigated, and the repair mechanism was clarified. The repaired area was dense and smooth, showed good compatibility with the original coating, and remained intact after oxidation at 1500 ℃ for 360 min. The addition of Al2O3 promoted the pyrolysis of PSO and formation of β-SiC, which was beneficial to the densification and oxidation resistance of the repaired coatings. The introduction of IPA improved the fluidity of the repair agents, and the repair agents infiltrated the coated C/C composites through the micropores on the damaged surface under capillary action, thereby enhancing the interfacial bonding strength. The weight loss of the damaged coating after oxidation decreased from 21.16 % to 0.48 % after repair. This work offers an approach for optimizing the repair of Si-based ceramic coatings.

Multifunctional Polymer Synthesis via Sequential Postpolymerization Modification Using a Single Aldehyde Repeat Unit: Allylation and Orthogonal Esterification and Thiol-ene Reaction.

Herein, we present a highly efficient method for synthesizing multifunctional polymers. This method involves the sequential postpolymerization modification (PPM) of a highly reactive aldehyde polymer. We introduce an allylic alcohol functionality into the polymer backbone via Barbier-type allylation, a process facilitated by easy-to-handle indium(0) powder. This step enables the formation of orthogonal pendants, secondary alcohol, and terminal alkene, which can be further functionalized through esterification and thiol-ene click reactions. All of these processes are carried out under mild conditions, ensuring high efficiency and a wide range of functional groups. Our study underscores PPM's operational simplicity and versatility in developing advanced polymer materials and expanding the scope of multifunctional polymer design.

Fabrication and Performance Evaluation of a Directly Immersed Photovoltaic-Thermal Concentrator for Building Integration

A novel concentrating photovoltaic-thermal solar collector was designed, fabricated and experimentally investigated at the University of Lleida, in Spain. Two designs based on two dielectric liquids, isopropyl alcohol (IPA) and deionised water (DIW), were developed. In both cases, the solar cells were directly liquid-immersed. The study includes experiments and numerical simulations. The proposed concentrator was incorporated into a testing unit to examine its potential as a façade by controlling light and thermal flux transmitted into a building. The results show promising electrical performance and acceptable thermal performance, with thermal losses ranging from 14 to 20 W °C−1m−2. The optical efficiency was around 73% in the case of the concentrator with DIW and about 76% for the one with IPA. Regarding electrical performance, the fill factors for IPA and DIW configurations are as follows: 62.8% and 61.7%, respectively. The comparison results reveal striking differences between the testing unit with and without solar concentrators, with the concentrator-equipped unit showing around four times lower illuminance and a 50% reduction in maximum heat fluxes and interior temperature. Generally speaking, it can be said that these energy-generating façades show satisfactory behaviour and offer interesting possibilities for building-integrated applications.

Development and Manufacturing Method of Electrodes for a High Temperature Oxygen Sensor

The article discusses the use of zirconium dioxide stabilized with yttria as an electrolyte for the formation of a high-temperature ceramic oxygen concentration sensor. The fundamental possibility of using such a material is due to the high electrical conductivity caused by the mobility of oxygen ions in the vacancies of the solid electrolyte. The operating principle of such a sensor as an electrochemical concentration element is discussed. It has been shown that the use of such sensors is relevant for various industries (including chemical, metallurgical, oil and gas, energy and others). Options for forming electrodes of an electrochemical sensor using various materials and deposition methods are considered. A method for forming a platinum coating using a chemical method using isopropyl alcohol and subsequent pyrolysis was tested. It has been experimentally shown that the chemical method is applicable for the formation of electrodes of an electrochemical sensor. The electrical characteristics of the resulting coatings were measured. The optimal composition of the reaction mixture and the required number of layers to create a stable operating electrochemical sensor have been determined. The dependence of the potential of the formed electrochemical sensor from stabilized zirconium oxide on oxygen concentration in a wide temperature range has been studied. It has been shown that when using a scheme of sequential transformations, hydrolysis of platinum tetrachloride - deposition on a substrate - reductive pyrolysis, it is possible to obtain a high-quality conductive coating for the formation of gas sensor electrodes. The optimal composition of the reaction mixture for the formation of platinum electrodes has been selected. The optimal number of layers was determined to ensure the required level of electrical conductivity of the electrodes. It has been shown that an electrochemical element based on zirconium dioxide and platinum electrodes, formed according to the scheme developed in this work, can be used as a high-temperature oxygen sensor.