Presence Of 2-propanol Research Articles

Transformations of cage alcohols in the presence of 2-propanol and H2SO4

A convenient approach for the synthesis of hydrocarbons by transformations of cage alcohols in the presence of 2-propanol and sulfuric acid has been proposed. Scalability, good yields and usage of readily available reagents along with synthetic convenience showed usefulness of proposed approach. This approach made it possible to obtain high preparative yields of difficult-to-reach cage hydrocarbons such as 2-methyladamantane, 2-phenyladamantane and homoadamantane. For some substrates, the potential to obtain corresponding saturated hydrocarbons or alkenylation products by varying the concentration of sulfuric acid under reaction conditions has been demonstrated.

Photocatalytic Degradation of Pharmaceutical Residues from Water and Sewage Effluent Using Different TiO2 Nanomaterials.

Pharmaceuticals are widely used and often discharged without metabolism into the aquatic systems. The photocatalytic degradation of pharmaceutical compounds propranolol, mebeverine, and carbamazepine was studied using different titanium dioxide nanostructures suspended in water under UV and UV-visible irradiation. Among three different photocatalysts, the degradation was most effective by using Degussa P25 TiO2, followed by Hombikat UV100 and Aldrich TiO2. The photocatalytic performance was dependent on photocatalyst dosage, with an optimum concentration of 150 mg L-1. The natural aquatic colloids were shown to enhance the extent of photocatalysis, and the effect was correlated with their aromatic carbon content. In addition, the photocatalysis of pharmaceuticals was enhanced by the presence of nitrate, but inhibited by the presence of 2-propanol, indicating the importance of hydroxyl radicals. Under optimum conditions, the pharmaceuticals were rapidly degraded, with a half-life of 1.9 min, 2.1 min, and 3.2 min for propranolol, mebeverine, and carbamazepine, respectively. In treating sewage effluent samples, the photocatalytic rate constants for propranolol (0.28 min-1), mebeverine (0.21 min-1), and carbamazepine (0.15 min-1) were similar to those in water samples, demonstrating the potential of photocatalysis as a clean technology for the effective removal of pharmaceuticals from sewage effluent.

Effect of liquid confinement on regioselectivity in the hydrosilylation of alkynes with cationic Rh(I) N-heterocyclic carbene catalysts.

Polymeric mesoporous monoliths were prepared via ring-opening metathesis polymerization (ROMP) from norbornene (NBE), 1,4,4a,5,8,8a-hexahydro-1,4,5,8-exo,endo-dimethanonaphthalene (DMN-H6), tris(norborn-2-enylmethylenoxy)methylsilane and the 1st-generation Grubbs catalyst [RuCl2(PCy3)2(CHC6H5)] in the presence of 2-propanol and toluene and surface grafted with 1-(2-((norborn-5-ene-2-carbonyl)oxy)ethyl)-3-ethyl-1H-imidazol-3-ium tetrafluoroborate. Subsequently, a supported ionic-liquid-phase (SILP) system was created by immobilizing the ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM][BF4] with the cationic catalyst [Rh((1-pyrid-1-yl)-3-mesitylimidazol-2-ylidene)(COD)+BF4-] (Rh-1; COD = 1,4-cyclooctadiene) dissolved therein. The regio- and stereoselectivity of Rh-1 dissolved in the IL and supported on the mesoporous monolith, referred to as Rh@SILPROMP, in the hydrosilylation of 1-alkynes with HSiMe2Ph was studied and compared to that of the homogeneous catalyst Rh-1 under biphasic conditions using methyl tert-butyl ether (MTBE) as a second organic phase. Different amounts of IL were used, which allowed for the creation of SILPs with different layer thicknesses. Rh@SILPROMP provided by far better β-(Z) selectivity for both aromatic and aliphatic 1-alkynes in comparison to Rh-1 used under biphasic conditions. The highest β-(Z) selectivity was obtained with the thinnest IL layer. No leaching of the IL or rhodium from the SILP system into the organic phase was observed, resulting in virtually metal-free hydrosilylation products. The data obtained with Rh@SILPROMP were also compared with those from previous studies with Rh-1 in the same IL supported on polyurethane-derived mesoporous monolithic supports (Rh@SILPPUR) and on mesoporous SBA-15 (Rh@SILPSBA-15). For the first time, the use of a liquid confinement created by both a SILP and the support itself to tune the transition state of an organometallic catalyst by non-covalent interactions and thus stereo- and regioselectivity is outlined.

Magnetic δ-FeOOH/Au nanostructures synthesized using γ-irradiation method and their catalytic activity for the reduction of 4-nitrophenol

γ-irradiation was used as an effective and environmentally friendly technique for the synthesis of magnetic iron oxide/Au nanostructures. Firstly, alkaline iron(III) precursor solutions, in the presence of 2-propanol and DEAE-dextran, were purged with nitrogen and γ-irradiated to doses of 14 and 75 kGy, which resulted in the reduction of Fe3+ to Fe2+ ions and formation of Fe(II)/Fe(III) or Fe(II) iron (hydr)oxide phases. After irradiation, gold nanoparticles (AuNPs) were attached to the surface of the magnetic nanostructures by in situ reduction of Au3+ with radiolytically formed Fe2+. At 75 kGy, simultaneous oxidation of Fe(OH)2 formed on irradiation and reduction of Au3+ led to the formation of superparamagnetic feroxyhyte (δ-FeOOH) nanodiscs decorated with well distributed, 11–24 nm AuNPs. The experiments performed with and without Fe(III) precursor and 2-propanol or tert-butanol as scavenger and in different atmospheres (N2, N2O) confirmed the main role of Fe2+ in Au3+ reduction. The catalytic activity of the δ-FeOOH/Au nanostructures was tested for the reduction of 4-nitrophenol to 4-aminophenol. Increasing the amount of added Au3+ enhanced the catalytic activity of the samples, but up to a certain amount depending on the size of formed AuNPs.

Two-dimensional MXenes as catalytic “flying carpets” to transport biomass valorization towards new horizons: The case of furfural catalytic transfer hydrogenation over noble-metal free niobium-based carbides

The reductive conversion of biomass-derived furfural through catalytic transfer hydrogenation (CTH) over non-precious metal catalysts is regarded as a promising strategy to successfully implement the biorefinery concept. Here, we show that two-dimensional niobium carbides (MXenes) efficiently catalyze the liquid-phase CTH of furfural in the presence of 2-propanol as hydrogen donor. At 160 °C Nb2CTx and Nb4C3Tx showed remarkable initial activity values (130 and 73 h−1, respectively), exceeding the one of pure Nb2O5 (21 h−1) by factor of 6.2 and 3.5. A targeted surface characterization by acid site titrations and X-ray photoelectron spectroscopy allowed to correlate the catalytic behavior with the acidic features and the peculiar surface chemistry of Nb-MXenes species. The presence of strong acid sites in Nb2CTx was associated to high initial activity, but also to a pronounced tendency to undergo deactivation. Differently, Nb4C3Tx, despite the lower initial activity, assured 70 % of furfural conversion after 8 h and it showed good stability over six runs. This study could bring new opportunities for the rational design of advanced noble metal-free catalysts with enhanced activity for biomass valorization.

Experimental Phase Equilibria of Carbon Dioxide and Methane Hydrates in the Presence of 2-Propanol and Sodium Chloride

Experimental Phase Equilibria of Carbon Dioxide and Methane Hydrates in the Presence of 2-Propanol and Sodium Chloride

Recovery of platinum and rhenium using selective precipitation induced by two-stage photochemical treatment

Platinum(IV) and rhenium(VII) can be selectively recovered as precipitates from aqueous solution by means of UV–Visible light irradiation in the presence of 2-propanol and acetone. When an aqueous solution (pH 13.2) containing platinum(IV) (10.9 mM) and rhenium(VII) (11.5 mM) was irradiated with 60 mW cm−2 light for 3 h, 95% of initial platinum content was recovered in the precipitate in its zerovalent state with high selectivity (the recovery efficiency was 24 times that of rhenium), while 96% of the initial rhenium content remained in the reaction solution. To recover the rhenium in the remaining solution, the platinum-containing precipitate was removed, and the collected solution was further irradiated in another photochemical cell. After 12 h of the second irradiation, 82% of the rhenium content in the initial solution (before the first irradiation) was recovered as a precipitate with a recovery efficiency that was 16 times that of platinum. Using this two-stage photochemical treatment, both the platinum and rhenium in the aqueous solutions were successfully recovered as precipitates with high selectivity.

Hg(II) and Ru(II) complexes of mono- and dichalcogenides of bis(diphenylphosphino)amine chelating ligands: Synthesis, characterization and catalytic activity in transfer hydrogenation of acetophenone derivatives

Reactions of C10H7-1-N(PPh2)2 (1) and C10H7-1-N(P(Se)Ph2)2 (2) ligands with mercury(II)iodide in equimolar ratio gave cis-[HgI2{1-κ2 P,P}] (3) and cis-[HgI2{2-κ2 Se,Se}] (4). Also, refluxing of monooxidized thioyl and selenoyl bis(phosphino)amine ligands C10H7-1-N(P(E)Ph2)(PPh2) (E = S (5), Se (6)) with [Ru(CO)3Cl2]2 dimer afforded cis-[Ru(CO)2Cl2{5-κ2 P,S}] (7) and cis-[Ru(CO)2Cl2{6-κ2 P,Se}] (8). Complexes 3, 4, 7 and 8 were identified and characterized by multinuclear NMR (1H, 13C, 31P and 77Se NMR) and IR spectroscopy. The molecular structure of 5 was determined by single X-ray crystallography. 5 is the first structurally characterized example of this kind of κ2 P,S -bidentate ligand. The novel ruthenium(II) complexes 7 and 8 show high catalytic activity in the transfer hydrogenation of acetophenone derivatives to 1-phenylethanol derivatives in the presence of 2-propanol as the hydrogen source.

Boron doped magnetic catalysts for selective transfer hydrogenation of furfural into furfuryl alcohol

A series of boron doped magnetic zirconium catalysts were developed for the selective transfer hydrogenation of biomass-derived furfural (FFR) into furfuryl alcohol (FA) using 2-propanol as hydrogen source and solvent. Full characterizations with XRD, SEM, TG, Py-IR, NH3-TPD, and CO2-TPD techniques were undertaken to uncover structural properties of magnetic catalysts. Boron doped magnetic zirconium catalysts endowing with adjustable acid-base sites exhibited excellent performance as well as good regenerability in the transfer hydrogenation of FFR, where almost 100% FA yield was achieved in the presence of 2-propanol and the catalyst still sustained good activity after being used five times. Suitable acidity/basicity ratio of 3.8 ~ 4.0 apparently benefited the selective production of FA. Gratifyingly, the activation energy for FA formation over Zr1B3FeO was as low as 48.3 kJ/mol. In addition, plausible reaction mechanism involving two H-transfer paths for transfer hydrogenation of FFR into FA under the catalysis of active Zr/B species was proposed.

Chemical and toxicological evaluation along with unprecedented transformation products during photolysis and heterogeneous photocatalysis of chloramphenicol in different aqueous matrices

As the presence of antibiotics in environmental waters enhances antimicrobial resistance, photolysis and heterogeneous photocatalysis of chloramphenicol (CAP) were evaluated in deionized water (DW) and insewage treatment plant (STP) effluent under black light and solar irradiation. Processes were compared in terms of CAP degradation, reaction kinetics, and electrical energy per order, as well as regarding theoretical toxicity, biodegradability, carcinogenicity, and mutagenicity of transformation products (TPs). Rate constants obtained under photolysis (0.008 min-1) and heterogeneous photocatalysis (0.18 min-1) only differed in DW. This is due to the generation of photo-active reactive oxygen species (HO· and HO2·-/O2·-) under photolysis in STP effluent, as verified by experiments in the presence of 2-propanol and chloroform. Natural organic matter and HCO3- were the main responsible for reducing CAP degradation in STP effluent. Fifteen TPs were identified during both processes in DW, 13 of which are unprecedented. TPs were formed mainly via HO· preferential attack on the aromatic ring and on the α-carbon, and some of them were classified as persistent and toxic, genotoxic, or carcinogenic by Toxtree software. Results confirm that solar photocatalysis is less costly than to photocatalysis under black light for wastewater treatment.

Crystal structures of [Li7(i-PrO)3(C4H10NO)3]2O and [Na(i-PrOH)2(C8H18NO2)]2.

The title compounds, hexa-kis-[μ3-2-(di-methyl-amino)-ethano-lato]hexa-μ2-iso-propano-lato-μ4-oxido-tetra-deca-lithium(I), [Li7(i-PrO)3(C4H10NO)3]2O (1), and {3-[(2-meth-oxy-eth-yl)(meth-yl)amino]-1,1-dimethylpropano-lato}diiso-prop-an-o-lsodium(I), [Na(i-PrOH)2(C8H18NO2)] (2), were crystallized in the presence of 2-propanol (i-PrOH, C3H7OH). The structure 1 has monoclinic symmetry (C2/c) and the asymmetric unit contains half of the compound. Title compound 2 has triclinic symmetry (P ) and the asymmetric unit is half of an inversion-symmetric aggregate. Both compounds consist of an alkali metal, an amino-alkoxide and a 2-propanol compound. Furthermore, the dimeric sodium aggregate 2 is build up by hydrogen bonding through the 2-propanol and the alkoxides. Compound 1 does not exhibit hydrogen bonding, due to the fact that the 2-propanol is deprotonated. In compound 1, benzene appeared as co-crystallate, but was suppressed by solvent masking because of strong disorder. The formula mass and density do not take account of the solvent.

Crystal Chemistry and Structural Complexity of Uranium(IV) Sulfates: Synthesis of U3H2(SO4)7(H2O)5·3H2O and U3(UO2)0.2(SO4)6(OH)0.4·2.3H2O with Framework Structures by the Photochemical Reduction of Uranyl.

Two uranium(IV) sulfate framework compounds were crystallized at room temperature from aqueous solutions containing uranyl ions by photochemical reduction in the presence of 2-propanol. U3H2(SO4)7(H2O)5·3H2O (1) crystallizes in space group P65 with a = 9.3052(17) Å, c = 53.515(10) Å, V = 4012.9(13) Å3, and Z = 6, and U3(UO2)0.2(SO4)6(OH)0.4·2.3H2O (2) is tetragonal, with space group P42/nmc, a = 25.624(3) Å, c = 8.9435(10) Å, V = 5872.2(11) Å3, and Z = 8. The structures of 1 and 2 are the most complex among uranium(IV) sulfates.

Unusual Reduction of Graphene Oxide by Titanium Dioxide Electrons Produced by Ionizing Radiation: Reaction Products and Mechanism

The research concerns the reduction of graphene oxide (GO) by excess electrons on TiO2 nanocrystallites, eTiO2–, produced with the aid of ionizing radiation in the presence of 2-propanol at acidic ...

Solubility and thermodynamic properties of mesalazine in {2-propanol + water} mixtures at various temperatures

The solubility of mesalazine in presence of 2-propanol as cosolvent in aqueous media was reported at T = (293.2 to 313.2) K. It was observed that the solubility of mesalazine is maximal in the 0.4 weight fraction of 2-propanol in the binary solvents. The performances of mathematical models of Jouyban-Acree, Apelblat-Jouyban-Acree, Jouyban-Acree-van't Hoff, modified Wilson, combined nearly ideal binary solvent/Redlich-Kister, UNIQUAC, NRTL and Wilson models in the solubility data representation were investigated. Two versions of Yalkowsky model were employed to estimate the solubility data. Dissolution and mixing apparent thermodynamic functions for mesalazine in studied solvents were also evaluated. Moreover, by means of inverse Kirkwood-Buff integrals method it is demonstrated that this drug is preferentially solvated by water in all the mixtures.

Aza-crown compounds synthesised by the self-condensation of 2-amino-benzyl alcohol over a pincer ruthenium catalyst and applied in the transfer hydrogenation of ketones.

A well-defined PNN-Ru catalyst was revisited to self-condense 2-aminobenzyl alcohol in forming a series of novel aza-crown compounds [aza-12-crown-3 (1), aza-16-crown-4 (2) and aza-20-crown-5 (3)]. All aza-crown compounds are separated and determined by NMR, IR, and ESI-MS spectroscopy as well as X-ray crystallography, indicating the saddle structure of 1 and the twisted 1,3-alternate conformation structure of 3. These aza-crown compounds have been explored to study ferric initiation of transfer hydrogenation (TH) of ketones into their corresponding secondary alcohols in the presence of 2-propanol with a basic t-BuOK solution, achieving a high conversion (up to 95%) by a ferric complex with 2 in a low loading (0.05 mol%).

Characterization of radiolytically synthesized feroxyhyte and oxidized magnetite nanoparticles

Iron(III) chloride deaerated alkaline aqueous colloidal solutions in the presence of 2-propanol and DEAE-dextran (diethylaminoethyl-dextran hydrochloride) were γ-irradiated with doses of 36 and 130 kGy. The dose rates were ~7 and ~31 kGy h−1. The extremely stable aqueous suspension of substoichiometric Fe2.83O4 magnetite nanoparticles ~4.7 nm in size were formed at a dose rate of ~7 kGy h−1 and at a dose of 36 kGy. At a dose of 130 kGy the anisotropic δ-FeOOH magnetic discs with a diameter of ~256 nm and thickness of ~40 nm were formed. Each disc has a substructure consisting of approximately eighteen laterally stacked thin nanodiscs of about 2.2 nm in thickness. At a higher dose rate of ~31 kGy h−1and at a dose of 36 kGy, XRD revealed the presence of highly substoichiometric Fe2.75O4 magnetite, whereas TEM analysis revealed the presence of ~4.3 nm magnetite nanoparticles along with rod-shaped γ-Fe2O3 nanoparticles. The values of isomer shift in Mössbauer spectra of about 0.33 mm s−1 showed that all Fe(II) in substoichiometric magnetites oxidized to Fe(III) one month after synthesis. At high dose and dose rate, the rolled rod-like δ-FeOOH magnetic nanoparticles were formed having the diffraction patterns with streaks, which are characteristic of tubular structures. The magnetic measurements showed exceptional intrinsic room-temperature magnetic properties of both δ-FeOOH nanostructures with the Curie temperature above 300 K. In order to ascertain the formation of Fe(II) intermediate products prior to their oxidation, γ-irradiated samples were isolated by admixing glycerol. The amounts of Fe(II) in glycerol-isolated solid samples were determined using Mössbauer spectroscopy. Carbonate Green Rust I [GR(CO32−)] and Fe(OH)2 intermediate phases were confirmed by XRD and Mössbauer spectroscopy. The amounts of Fe2+ in the acidified solutions containing dissolved γ-irradiation ferrous products were determined using the potassium permanganate titration. The amounts of Fe2+ were 68.9% and 96.1% at doses of 36 and 130 kGy, respectively. Thus, at a dose of 130 kGy the radiolytically generated Fe(OH)2, after coming in contact with oxygen and CO2 from the air, topotactically oxidized to GR(CO32−) and further to δ-FeOOH without any structural changes. The lower dose rate (~7 kGy h−1) favored the δ-FeOOH nanodisc morphology, whereas the higher dose rate (~31 kGy h−1) favored the formation of tubular rod-like δ-FeOOH nanoparticles.

Photodegradation of metoprolol in the presence of aquatic fulvic acids. Kinetic studies, degradation pathways and role of singlet oxygen, OH radicals and fulvic acids triplet states

Metoprolol is a pharmaceutical used for the treatment of cardiovascular diseases and disorders, whose frequent detection in surface waters raises concern. Indirect photodegradation is an important degradation pathway in waters and dissolved organic matter has a major role as photosensitizer. In this study, metoprolol photodegradation, in the absence and in the presence of fulvic acids extracted from the Vouga River (Portugal) (VRFA), was assessed under simulated sunlight. While metoprolol direct photodegradation was deniable, indirect photolysis occurred under the presence of VRFA. It followed a pseudo-first order kinetics and after 72 h of irradiation there was a decrease of metoprolol concentration of ∼80 %. The OH radical (OH) was verified to be the main reactive species (RS) responsible for the photosensitized degradation of metoprolol, but other RS are also involved, probably triplet excited states of FA (3FA*) and singlet oxygen (1O2), as demonstrated by the higher inhibition of the photodegradation in presence of sodium azide than in presence of 2-propanol. Based on a previous identification of photoproducts, tentative degradation mechanisms were here proposed. Photoproducts analysis after 24 h irradiation in the absence and presence of scavengers, shown that different RS are involved in the formation of different products/intermediates.

Efficient photocatalytic hydrogen production over titanate/titania nanostructures modified with nickel

Abstract Nickel-modified titanate/TiO2 catalysts were prepared by deposition of nickel ions onto hydrothermally prepared titanate supports, followed by hydrogen temperature-programmed reduction. Two different nickel precursors (hydroxide and carbonate) were used to tune reducibility and to vary the crystal phase structure of the final catalysts. The precursor reducibility and functional properties of the final catalysts were investigated systematically using various characterisation techniques. The results revealed a more facile reduction of the hydroxide precursor compared to its carbonate counterpart. Moreover, it was found that the formation of the anatase phase was favoured by the use of the hydroxide precipitation agent. The photocatalytic activity towards hydrogen production of the prepared catalysts was evaluated in the presence of 2-propanol under simulated solar light irradiation. A thorough study of the photocatalytic performance of the synthesised catalysts was conducted as a function of the precipitation agent used and the reduction temperature applied. The catalyst with dominant anatase crystal phase displayed the highest photocatalytic activity with a maximum H2 production rate of 1040 μmol h−1 g−1, this being more than four times higher than that of its carbonate counterpart. The catalysts with titanate structure showed similar activity, independent of the precipitation method used. The nanotubular structure was found to be the dominant factor in the stability of photocatalysts under long-run working conditions.

The Role of Saccharomyces cerevisiae Yeast and Lactic Acid Bacteria in the Formation of 2-Propanol from Acetone during Fermentation of Rye Mashes Obtained Using Thermal-Pressure Method of Starch Liberation.

This study set out to assess the acetone content in rye sweet mashes prepared using the thermal-pressure method of starch liberation, and to investigate the formation of 2-propanol during the fermentation process. In the first set of experiments, we evaluated the correlation between the color and the content of acetone and furfural in industrially produced sweet mashes (n = 37). The L * value was negatively correlated with the content of both acetone and furfural, while chromatic parameters a * and b * and the yellowness index (YI) had strong positive correlations with acetone (r > 0.9) and furfural (r > 0.8 for a * and r > 0.9 for b * and YI). In the second set of experiments, we assessed the concentration of acetone and 2-propanol in distillery rye mashes, fermented by S. cerevisiae yeast and lactic acid bacteria. The influence of fermentation temperature on the formation of 2-propanol was also evaluated. The presence of 2-propanol in the post-fermentation media was confirmed, while a decrease in acetone content was observed. Fermentation temperature (27 °C or 35 °C) was found to have a significant effect on the concentration of 2-propanol in trials inoculated with lactic bacteria. The content of 2-propanol was more than 11 times higher in trials fermented at the higher temperature. In the case of yeast-fermented mashes, the temperature did not affect 2-propanol content. The acetone in the sweet mash was assumed to be a precursor of 2-propanol, which was found in the fermented mashes.

The impact of dextran sulfate on the radiolytic synthesis of magnetic iron oxide nanoparticles

Iron(III) chloride deoxygenated alkaline aqueous colloidal solutions in the presence of 2-propanol and dextran sulfate were γ-irradiated with doses of 36 and 130 kGy. The dose rate was ∼31 kGy h−1. The samples isolated by washing with water mainly consisted of γ-FeOOH (lepidocrocite), δ-FeOOH and schwertmannite. The samples isolated by washing with ethanol contained mainly α-FeOOH (goethite), δ-FeOOH (feroxyhyte) and iron(III) hydroxide sulfate. At lower dose (36 kGy) magnetite (Fe3O4) was formed. The samples isolated by admixing glycerol consisted of the intermediate phases Fe(OH)2, GR(SO42−) and non-stoichiometric FeS1-x (mineral name mackinawite). The amounts of Fe(II) in glycerol-isolated solid samples were 60.5% and 82.6% as determined by Mössbauer spectroscopy at doses of 36 and 130 kGy, respectively. The amount of Fe2+ in the acidified solutions containing dissolved γ-irradiation products was determined using potassium permanganate titration. The amounts of Fe2+ in acidified solutions were 72.0% and 92.0% at doses of 36 and 130 kGy, respectively. Thus, although the conventionally isolated powders consisted exclusively of Fe(III) products, the high reducing conditions upon γ-irradiation were confirmed by capturing the Fe(II) intermediate phases and by quantitative determinations of ferrous ions in the solid samples and solutions containing dissolved γ-irradiation products.