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Azuma S., Shimada J., Tsunashima K., et al. Equilibrium Phase Relations and Dissociation Enthalpies of Tri- n-butylalkenylphosphonium Bromide Semiclathrate Hydrates. Journal of Chemical and Engineering Data, 67, 6, 1415 - 1420, May 25, 2022, © 2022 American Chemical Society. https://doi.org/10.1021/acs.jced.2c00146., Semiclathrate hydrates (SCHs) have received attention as thermal storage materials because of their equilibrium temperature and relatively large dissociation enthalpy. The alkyl length of quaternary onium cations significantly affects the equilibrium temperature and dissociation enthalpy of quaternary onium salt SCHs. To investigate the effects of the double bond introduced in onium cations, in the present study, the thermodynamic stability of tri-n-butylalkenylphosphonium bromide (P444(alkenyl)-Br: alkenyl = 3-butenyl (3═1) or 4-pentenyl (4═1)) SCH was investigated. The equilibrium temperatures and the dissociation enthalpies were determined to be (277.5 ± 0.1) K and (199 ± 2) J/g for P444(3═1)-Br SCH, and (274.8 ± 0.1) K and (188 ± 2) J/g for P444(4═1)-Br SCH. The equilibrium temperatures of P444(3═1)-Br SCH and P444(4═1)-Br SCH were lower than those of the corresponding normal alkyl SCHs (P4444-Br and P4445-Br), although the equilibrium temperature of tri-n-butylallylphosphonium bromide SCH was higher than that of the P4443-Br SCH.

Jin Shimada, Moe Yamada, Atsushi Tani et al. Thermodynamic Properties of Tetra-n-butylphosphonium Dicarboxylate Semiclathrate Hydrates. Journal of Chemical & Engineering Data, 67 (1), 67-73, January 13, © 2022 American Chemical Society. https://doi.org/10.1021/acs.jced.1c00741, Semiclathrate hydrate (SCH) is one of the phase change materials suitable for cold energy storage. Thermodynamic properties of SCHs, such as an equilibrium temperature and the dissociation enthalpy, depend on the size and shape of the guest substances. In the present study, to reveal the effects of steric conformations of the guest anions on the thermodynamic properties of SCHs, tetra-n-butylphosphonium dicarboxylate (TBP-DC) SCHs, where the anion was oxalate (TBP-Oxa), malonate (TBP-Mal), succinate (TBP-Suc), glutarate (TBP-Glu), maleate (TBP-Male), or fumarate (TBP-Fum), were investigated. TBP-Oxa, -Mal, -Suc, and -Fum SCHs had similar equilibrium temperatures, whereas the equilibrium temperatures of TBP-Glu and -Male SCHs were higher. This suggests that the size and conformation of glutarate and maleate anions are appropriate for the cage structures of SCHs. Moreover, we compared the equilibrium temperatures of TBP-Suc, -Male, and -Fum SCHs because TBP-Suc, -Male, and -Fum have similar anion structures. The equilibrium temperature of TBP-Suc SCH was similar to that of TBP-Fum SCH, whereas TBP-Male SCH showed a higher equilibrium temperature. This result implies that the succinate anion is accommodated in the trans conformation, similar to the fumarate anion, in the hydrate cages.

The synthesis of spiropyran dyes exhibiting solvent-driven isomerization even in the dark condition is an important subject for the design of optical materials. A conventional synthesis strategy involves the conjugation of indoline moieties with electron-deficient aromatic moieties. Herein, we report that a spiropyran conjugated with a hydroxynaphthalene moiety (1) is a new member exhibiting solvent-driven isomerization, even bearing an electron-donating −OH moiety. The dye exists as a colorless spirocyclic (SP) form in nonpolar media. It, however, shows a blue color in polar media, especially in aqueous media, due to the formation of ring-opened merocyanine (MC) forms, where the isomerization terminates in 10 s even at room temperature. The spontaneous SP → MC isomerization originates from the MC forms stabilized by the highly delocalized π-electrons on the hydroxynaphthalene moiety. The solvation in polar media and the hydrogen bonding interaction with water molecules decrease the ground-state energy of the MC forms, triggering spontaneous isomerization. The dye exhibits two MC absorption bands assigned to the trans–trans–cis (TTC) and cis–trans–cis (CTC) isomers. The absorbance of the CTC band increases more significantly with an increase in the water content, and the increase exhibits a linear relationship with a hydrogen-bond donor acidity of solvents. The phenolate oxygen of the CTC form has larger hydrogen-bond acceptor basicity, resulting in stronger stabilization by the water molecule.

Phase equilibrium (temperature–composition) relations of the tetra-n-butylphosphonium trifluoroacetate (TBP-TFA) + water binary system including solid (semiclathrate hydrate, SCH)-liquid equilibria and liquid-liquid equilibria were investigated. Phase diagram of TBP-TFA SCH exhibited peritectic behavior. The maximum decomposition temperature (peritectic temperature) of TBP-TFA SCH at atmospheric pressure were 275.9 ± 0.1 K. The stoichiometric composition of TBP-TFA SCH was located at the mole fraction of 0.027 ± 0.002. The decomposition enthalpy of TBP-TFA SCH was 199 ± 2 J/g. At temperatures above the lower critical solution temperature (LCST), the liquid-liquid phase separation appeared. Interestingly, the composition at the LCST was 0.026 ± 0.002, which is very similar to the stoichiometric composition of TBP-TFA SCH. It implies that both cluster-based solution structures are similar.

Ternary polymer blends of polyamide 6 (PA6), polycarbonate (PC), and phenol novolac (PN) were prepared by a melt mixing process. PN catalyzes the exchange reaction between PA6 and PC and promotes the generation of a copolymer, which improves the compatibility. Herein, the catalytic effect of PN was experimentally supported by an increase in torque during melt mixing and mass signals from copolymer fragments detected by mass spectroscopy. The characteristic behavior of the exchange reaction changed significantly with increasing PN amount. The promotion of in situ copolymer generation led to the formation of ternary blends, which show homogeneous morphologies and superior mechanical properties, such as high stiffness and good elongation, compared with those of the binary blends without PN. Using excess PN causes some drawbacks like brittleness due to the decomposition of the PC component. A loading amount of 1–3 wt % PN was suitable for achieving a ternary blend with improved properties.

Ternary polymer blends comprising miscible and immiscible components are examined to improve the mechanical properties of polyamide 6 (PA6) under humid and high-temperature conditions. Miscible polymers increase the glass transition temperature (Tg), owing to their strong inter-molecular interactions, while phase-separated immiscible polymers reinforce the physical properties of PA6 as filler materials. Ternary blends exhibit these combined miscible and immiscible component contributions. Thus, in this study, ternary blends comprising PA6, polyethylene terephthalate (PET, immiscible component), and phenol novolac (PN, miscible component) are prepared by melt mixing. The PA6 stiffness in the water-absorbed state is reinforced by PET. Moreover, the proposed PA6/PET/PN ternary blends exhibit higher Tg values and lower water absorption rates than those of the PA6/PET binary blend, owing to the PN contribution. The PET and PN contributions are achieved independently and can be controlled via the composition ratios of the component polymers. Multifaceted property tailoring is thus demonstrated.

Generating hydrogen peroxide (H2O2) from water and dioxygen (O2) by photocatalysis is one ideal artificial photosynthesis for solar fuel production. Several early reported powdered photocatalysts, however, produce small amounts of H2O2 ( 420 nm) in pure water with O2, successfully produces millimolar levels of H2O2 via water oxidation by valence band holes and selective two-electron reduction of O2 by conduction band electrons. The incorporation of triply branched MTI units creates a condensed melem layer. This facilitates efficient intra- and interlayer transfer of photogenerated charge carriers and shows high electrical conductivity. The solar-to-chemical conversion efficiency for H2O2 production on the catalyst is 0.18%, which is higher than that of natural photosynthesis (∼0.1%) ...

The hypochlorite anion (OCl−), a reactive oxygen species (ROS), is an important microbicidal agent in the immune system. Accurate and selective detection of OCl− in environmental and biological samples by a fluorescent molecular sensor is an important subject. All previously reported sensors, however, have suffered from tedious multi-step synthesis for the sensors and the use of large amounts of organic solvents for the analysis. Herein, we report that a coumarin–dihydroperimidine dye prepared by facile condensation behaves as a fluorescent sensor for OCl− in 99% water. The sensor exhibits weak fluorescence, but OCl−-selective dehydrogenation of its dihydroperimidine unit creates a strong blue fluorescence. This turn-on fluorescence response facilitates selective and sensitive detection of OCl− in the physiological pH range. Ab initio calculation revealed that the fluorescence enhancement by OCl− is triggered by intramolecular proton transfer from the coumarin –OH to the imine nitrogen of the formed perimidine moiety.

Colloidal suspensions of gold nanoparticles (AuNPs) in water can be prepared by heating water containing HAuCl4 with citric acid as reductant and surface stabilizing reagent. This thermal reduction method, however, promotes aggregation of the formed AuNPs, resulting in bimodal distribution of AuNPs. Here we report that UV (254 nm) irradiation of water containing HAuCl4 with citric acid at room temperature successfully reduces HAuCl4 and produces monodispersed AuNPs, while suppressing aggregation of the formed AuNPs. Changing the intensity of UV light or the amount of citric acid added successfully produces AuNPs with tunable sizes and narrow size distributions.

Tafenoquine (TQ), a fluorescent antimalarial drug, was used as a receptor for the fluorometric detection of hypochlorite (OCl−). TQ itself exhibits a strong fluorescence at 476 nm, but OCl−-selective cyclization of its pentan-1,4-diamine moiety creates a blue-shifted fluorescence at 361 nm. This ratiometric response facilitates rapid, selective, and sensitive detection of OCl− in aqueous media with physiological pH. This response is also applicable to a simple test kit analysis and allows fluorometric OCl− imaging in living cells.

Quantitative determination of toxic cyanide anions (CN−) in biological samples is an important subject. We synthesized a naphthalimide–coumarin conjugate with a simple imine linker (1), which behaves as a fluorescent receptor for ratiometric quantification of CN−. It exhibits green naphthalimide fluorescence at 533 nm, originating from the excited-state intramolecular charge transfer (ESICT) from coumarin to naphthalimide fluorophores. Selective CN− addition to the imine linker affords an α-amino nitrile product. This suppresses ESICT and creates coumarin fluorescence at 444 nm and naphthalimide fluorescence at 533 nm originating from direct photoexcitation of the respective fluorophores. The emission intensity at 533 nm is maintained upon CN− addition and can be used as an internal standard for analysis. This ratiometric response enables self-calibrating CN− quantification based on the intensities of two emissions in solution and in cells. This facilitates rapid (within 3 min), selective, and sensitive ratiometric detection of very low levels of CN− (>1.8 μM).

A naphthalimide–dicyanoisophorone conjugate (1) was synthesized and used as a chemodosimeter for fluorometric and colorimetric detection of hypochlorous acid (HClO) and hypochlorite (OCl–) in aqueous media. This molecule shows a strong reddish-purple color and a weak fluorescence, but HClO/OCl–-selective oxidative decomposition of the dicyanoisophorone moiety promotes a color fading and a fluorescence enhancement. Ab initio calculation revealed that these responses to HClO/OCl– originate from the suppression of intramolecular electron transfer from the photoexcited naphthalimide moiety by the decomposition of the dicyanoisophorone moiety. These colorimetric and fluorometric responses facilitate relatively rapid (∼5 min), selective, and sensitive detection of HClO/OCl– as low as ∼1.3 μM under physiological conditions.

We investigated the design of relatively large cyclones with large amounts of airflow containing dust that are used in actual dust collection plants. In order to obtain basic data on the design of conical cyclones with a Reynolds number of approximately 8.9 × 105, we compared the fluid analysis results with the experimental results on dust collection and particle classification performance for conical cyclones to which apex cones and stabilizers were attached. Then, we elucidated the relationship between the flow conditions inside the conical cyclone with a Reynolds number of 8.9 × 105 and dust collection and particle classification performance.

An amino-substituted spirothiopyran, when added to an aqueous solution containing gold nanoparticles (AuNPs), promotes aggregation of AuNPs at room temperature in the dark. The sulfur atom of the spirothiopyran has high nucleophilicity due to the substitution of electron-donating amino groups and is bound to the AuNP surface via covalent Au–S binding. This promotes spontaneous spirocycle opening of the spirothiopyran and produces a positively charged indolinium moiety on the AuNP surface. This reduces electrostatic repulsion between the AuNPs and promotes their aggregation. Changing the amount of the spirothiopyran added successfully produces AuNP aggregates with tunable sizes (40–1300 nm) and narrow size distributions with standard deviation being less than 30%. This system therefore has potential to be a new simple method for self-assembly of AuNPs.

A benzoxadiazole–thiourea conjugate ( 1 ) was synthesized and used for chemodosimetric detection of Hg 2+ in aqueous media. The compound 1 shows a selective and quantitative fluorescence quenching upon addition of Hg 2+ . This is promoted via a Hg 2+ -induced desulfurization of the thiourea moiety, leading to a formation of an imidazoline derivative, 2 . Ab initio molecular orbital calculation reveals that the formation of imidazoline moiety by the reaction of 1 with Hg 2+ promotes a photoinduced electron transfer from the aniline moiety to the excited state benzoxadiazole moiety and results in fluorescence quenching.

A new bis-quinolylimine ligand containing an azadiene moiety, 1,4-bis(2-quinolyl)-2,3-diaza-1,3-buthadiene (1), was synthesized by one-step facile condensation. This simple ligand, when dissolved in acetonitrile, shows a Cu2+-selective fluorescence enhancement. Coordination of 1 with Cu2+ produces two kinds of complexes with 1:1 and 1:2 stoichiometries. The 1:2 complex shows a strong fluorescence (ΦF = 0.37), while the 1:1 complex does not (ΦF

Two kinds of amphiphilic graft copolymers, PAA-g-P(MMA-co-BP) and P(AA-co-BP)-g-PMMA, consisting of polar poly(acrylic acid) (PAA), less polar poly(methyl methacrylate) (PMMA), and benzophenone (BP) photosensitizing units, have been synthesized. These polymers, when used as a photosensitizer for isomerization of trans-β-methylstyrene, show a sensitization activity controlled by solvents. In benzene and chloroform, P(AA-co-BP)-g-PMMA forms a micelle structure consisting of aggregated P(AA-co-BP) core with dissolved PMMA units at the outer sphere. This suppresses a triplet energy transfer (TET) from the excited state BP units to olefin and, hence, shows lower sensitization activity than a bulk sensitizer (4-methoxybenzophenone: MBP). In methanol, both polymers form a weak aggregate of less polar PMMA units containing dissolved PAA units. The internal cavity of the aggregate is less polar and stabilizes the excited state BP units. This accelerates a TET from the excited state BP units to olefin and shows higher sensitization activity than MBP.

Fluorescence properties of rhodamine–diacetic acid conjugates ( 1a – e ), with different alkyl chain length (C2–C6) between the rhodamine and the diacetic acid moieties, have been studied in the presence of Cu 2+ and Hg 2+ . Without cations or with other cations, these probes show almost no fluorescence; however, addition of Cu 2+ creates strong green fluorescence at around 530 nm, while Hg 2+ addition shows weak orange fluorescence at around 580 nm. The Cu 2+ -induced green fluorescence originates from self-assembled aggregates of the probes formed by coordination association with multiple Cu 2+ ions. Coordination association of the probes with Cu 2+ is weakened with an increase in the chain length of the probes due to longer distance between the amide oxygen and the diacetic acid binding sites. In contrast, the green fluorescence intensity is not related to the coordination association strength; some probes show high fluorescence intensity. This is probably because alkyl chains sterically affect the alignment of the probes during aggregation interaction and, hence, produces aggregates with different fluorescence property.

Effects of poly- N -isopropylacrylamide (polyNIPAM) on the fluorescence properties of core/shell type CdS/Cd(OH) 2 nanoparticles (NPs) have been studied in water. The NPs show strong fluorescence at low temperature, but the intensity decreases at >32 °C, allowing an on–off fluorescence switching by temperature. The heat-induced fluorescence quenching is due to the phase transition of polyNIPAM from coil to globule state. The NPs in solution associate with polyNIPAM via a hydrogen bonding interaction. Upon heating the solution, the NPs are confined within the polymer matrices during polymer aggregation. The aggregated polymer suppresses the incident absorption of inner NPs, resulting in fluorescence quenching. A notable feature obtained by the polyNIPAM addition is the enhanced thermal stability of NPs. The NPs confined within the polymer matrices are separated from each other. This therefore suppresses the coalescence of NPs, resulting in high stability even at high temperature.

A simple copolymer, poly(NIPAM- co -RD), consisting of N -isopropylacrylamide (NIPAM) and rhodamine (RD) units, behaves as a fluorescent temperature sensor exhibiting selective fluorescence enhancement at a specific temperature range (25–40 °C) in water. This is driven by a heat-induced phase transition of the polymer from coil to globule . At low temperature, the polymer exists as a polar coil state and shows very weak fluorescence. At >25 °C, the polymer weakly aggregates and forms a less polar domain within the polymer, leading to fluorescence enhancement. However, at >33 °C, strong polymer aggregation leads to a formation of huge polymer particles, which suppresses the incident light absorption by the RD units and shows very weak fluorescence. In the present work, effects of polymer concentration and type of acrylamide unit in the polymer have been investigated. The increase in the polymer concentration in water leads to a formation of less polar domain even at low temperature and, hence, widens the detectable temperature range to lower temperature. Addition of N - n -propylacrylamide (NNPAM) or N -isopropylmethacrylamide (NIPMAM) component to the polymer, which has lower or higher phase transition temperature than that of NIPAM, enables the aggregation temperature of the polymer to shift. This then shifts the detectable temperature region to lower or higher temperature.

An anthracene (AN) derivative bearing azacrown ether (1-aza-18-crown-6) and cyclen (1,4,7,10-tetraazacyclododecane) receptors ( L1 ) has been synthesized. Effects of proton (H + ) and metal cations (K + and Zn 2+ ) on the fluorescence properties of L1 have been studied in water and methanol. In water, H + addition to L1 leads to a fluorescence intensity ( I F ) increase. Potentiometrical pH titration reveals that strong I F enhancement of L1 requires monoprotonation of both azacrown and cyclen moieties. Addition of Zn 2+ and/or K + is ineffective for I F enhancement because these cations do not coordinate with the azacrown moiety, leading to an electron transfer (ET) from the azacrown nitrogen to the photoexcited AN moiety. In methanol, the azacrown and cyclen moieties of L1 coordinate with K + and Zn 2+ , respectively. Zn 2+ or K + addition to L1 shows very small or moderate I F enhancement because of ET from the uncoordinated azacrown or cyclen nitrogen to the excited AN. Addition of both K + and Zn 2+ , however, still shows moderate I F enhancement, although both macrocycles coordinate with the respective metal cations. Ab initio calculation reveals that the azacrown–K + coordination is weakened by an electrostatic repulsion between K + and Zn 2+ within the complex. This allows ET from the azacrown nitrogen to the excited AN, resulting in an insufficient I F enhancement.

S-Methylsulfonium salts obtained by a desulfurization process for light oils, based on a methylation of sulfur-containing compounds with CH3I and AgBF4 followed by precipitation, have been used as an initiator for cationic ring-opening photopolymerization of epoxide (glycidyl phenyl ether, GPE). The sulfonium salts obtained from light oils demonstrate higher initiation activity than the salts of pure dibenzothiophenes (DBTs) and benzothiophenes (BTs). These salts are derived from highly alkyl-substituted DBTs and BTs, which have a higher molar extinction coefficient and have a sulfur atom of lower nucleophilicity than the pure DBTs and BTs. These salts are, therefore, easily photoexcited and eliminate the S-methyl group, thus resulting in higher initiation activity. The obtained findings demonstrate potential use of the sulfonium salts derived from light oils as an initiator for cationic photopolymerization.

1,4,7,10-Tetraazacyclododecane (cyclen) bearing two anthrylmethyl groups (1,7-bis(9-anthrylmethyl)-1,4,7,10-tetraazacyclododecane, L2) was synthesized and used as a fluorescent chemosensor for detection of pH and transition metal cations in aqueous solution. The fluorescent response and complexation properties of L2 were studied in comparison with those of a cyclen with a single anthrylmethyl group that was previously reported (1-(9-anthrylmethyl)-1,4,7,10-tetraazacyclododecane, L1). Although L2 showed a less sharp response than L1, L2 demonstrated fluorescence behavior similar to that of L1, showing strong fluorescence at a low-pH region (pKa = 8.4) and in the presence of Zn2+ and Cd2+ but showing weak fluorescence at a high-pH region and in the presence of Cu2+. Chemical stability test by 1H NMR revealed that L2 is very stable even if left to stand under a humid atmosphere for 30 days, suggesting that L2 may be a potential effective fluorescent chemosensor for detection of pH and transition metal cation...

N-(9-Anthrylmethyl)-1,4,7,10-tetraazacyclododecane (AC), which acts as an efficient fluorescent chemosensor for detection of pH and metal cations in aqueous solution, was covalently grafted on a Na...

Desulfurization and denitrogenation of light oils have been investigated on the basis of adsorption of sulfur- and nitrogen-containing compounds on methyl viologen-modified aluminosilicate (MV2+/AS) adsorbent. Sulfur and nitrogen compounds, dissolved in n-tetradecane or xylene solution (model light oil), were adsorbed on the surface of MV2+/AS via the formation of a charge transfer (CT) complex with MV2+ by stirring at room temperature and removed successfully from the oil. Desulfurization of actual light oils, however, failed because aromatic hydrocarbons present in the oils suppress the adsorption of sulfur compounds. On the contrary, adsorption of nitrogen compounds was hardly suppressed, even in the presence of a large quantity of aromatics because of lower ionization potential of the nitrogen compounds. By employing the process, the nitrogen concentrations of actual light oils were decreased successfully to less than 35% of the feed values. The nitrogen compounds, adsorbed on MV2+/AS, were desorbed b...

The photoluminescence from Mn2+-doped ZnS (ZnS:Mn) nanoparticles prepared in an AOT/isooctane reverse micellar system was investigated. The composition (Mn content) and photoluminescent properties of the nanoparticles depend on the composition of the feed solution and the water content (Wo) of reverse micellar solution. The emission intensity from Mn2+ ions at 580 nm depends mainly on the Mn content in the nanoparticles rather than the nanoparticle size, when the nanoparticle size is controlled by varying the Wo value at a constant feed composition of Zn and Mn.

Desulfurization of vacuum gas oil (VGO) has been investigated based on chemical oxidation of sulfur-containing compounds using H2O2 and acetic acid (AcOH), followed by extraction of the oxidized co...

An oxidative desulfurization process for light oil has been investigated using a vanadosilicate molecular sieve as the catalyst and H2O2 as the oxidizing agent. The catalytic activities for three k...

S-Methylsulfonium salts, obtained by desulfurization of vacuum gas oil (VGO) and catalytic-cracked gasoline (CCG) based on alkylation and a subsequent precipitation process, were used as initiator for polymerization of epoxide (glycidyl phenyl ether: GPE). The initiation behavior and activity for the salts obtained from VGO and CCG were compared with those obtained from light oil. Both the salts from VGO and CCG showed almost no activity at room temperature but become active with an increase of temperature, thus indicating that the salts act as thermal latent initiator. The initiation activity for the salts from VGO was relatively low, but the salts from CCG showed significantly higher activity than the salts from light oil. Most of the salts, obtained from CCG, are derived from less nucleophilic thiophenes, and therefore unstable against thermal stimulation, thus giving the higher initiation activity.

Polymer-supported sulfonium salt (PS) was synthesized by the reaction of sulfur-containing compounds, present in light oil, with iodomethylpolystyrene (IMP) and AgBF4. Dibenzothiophenes (DBTs) and benzothiophenes (BTs) in the oil were successfully anchored on the IMP as the corresponding sulfonium salts, via nucleophilic displacement of the iodide atom on IMP with the sulfur atom on DBTs and BTs. By this means, the sulfur content of the light oil was decreased successfully to the required deep desulfurization level (0.05 wt%). The PS, obtained from light oil, showed significantly high activity as phase transfer catalyst for the anion exchange reaction of 1-bromooctane with potassium thiocyanate in the organic/water two-phase system. This high activity for the PS results since the highly lipophilic alkyl-substituted DBTs and BTs are anchored on the PS as the sulfonium salts.

A desulfurization process for light oil has been investigated using a polymer-supported imidation agent (PI, sodium N-chloro-polystyrenesulfonamide). When n-tetradecane solution (model light oil) containing dibenzothiophene (DBT) was stirred with methanol in the presence of PI and acetic acid at a temperature of 323 K, DBT was chemically adsorbed on the PI, via the imidation of sulfur atoms on DBT by the PI, and removed successfully from the oil. The polymer obtained was insoluble to the solutions and could be recovered by filtration. The present process was found to be also effective for the desulfurization of actual light oil: the sulfur concentration of commercial light oil was decreased successfully from 400 ppm to less than 50 ppm (ultra-deep desulfurization level).

Photochemical production and recovery process of biphenyls from the desulfurization products, obtained by oxidative desulfurization (ODS) of light oils, has been investigated. The S-oxidized dibenzothiophenes (DBT sulfones), when dissolved in 2-propanol, were converted successfully into the corresponding biphenyls by photoirradiation at wavelengths of λ > 280 nm using a high-pressure mercury lamp, under conditions of nitrogen atmosphere and at room temperature. The present photochemical process was found to be also effective for the production of biphenyls from the DBT sulfones present in the desulfurization products of low-aromatic-content light oils. The quantitative recovery of biphenyls from the resulting 2-propanol solution was carried out successfully by adsorption using neutral aluminum oxide and subsequent elution with dichloromethane/n-hexane (20/80 v/v) mixture.

S-Methylsulfonium salts, obtained by a desulfurization process for light oil based on the methylation of sulfur-containing compounds using CH3I and AgBF4 and subsequent precipitation, were used as a thermal latent initiator for cationic ring-opening polymerization of epoxide (glycidyl phenyl ether, GPE). The sulfonium salts, obtained from the light oil, showed good thermal latency and demonstrated significantly high initiation activity for the polymerization of GPE. The activity of the salts was rather higher than that obtained using the salts of pure dibenzothiophenes (DBTs) and benzothiophenes (BTs) as the model sulfonium salts. The salts, obtained from light oil, are derived from highly alkyl-substituted DBTs and BTs in light oil, of low nucleophilicity (low electron density on the sulfur atom), and therefore are unstable against thermal stimulation, thus giving the high initiation activity for the polymerization.

The extraction and separation of transition metals has been investigated using several inorganic adsorbents (silica gel, MCM-41, and aluminum oxide), modified with ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) as chelating ligands. The metal ions in aqueous solution were coordinated successfully by the ligands on the surface of the adsorbents under moderate conditions. Metal−ligand complexes formed on the adsorbents effectively in the region of low pH (1−2) but scarcely formed at pH > 4. Silica gel modified with EDTA (silicaED) was shown to be the most effective adsorbent for the extraction of metals and to form specific metal−EDTA complexes, with stability constants lying in the order Cu2+ > Ni2+ > VO2+ > Zn2+ > Co2+ > Mn2+. The relatively good separation of these six adjacent metals was therefore also carried out using the silicaED. The metals coordinated on the silicaED could be desorbed completely by putting the material into contact with 1 mol/L aqueous HCl solu...

Upconverting phosphor fine particles (Y2O3:Yb,Er) have been prepared, using an emulsion liquid membrane (ELM, water-in-oil-in-water (W/O/W) emulsion) system, consisting of Span 83 (sorbitan sesquioleate) as the surfactant and VA-10 (2-methyl-2-ethylheptanoic acid), DTMBPA (bis(1,1,3,3-tetramethylbutyl)phosphinic acid), or Cyanex272 (bis(2,4,4-trimethylpenthyl)phosphinic acid) as the extractant (cation carrier). The Y, Yb, and Er ions were extracted, from the external water phase, and stripped into the internal water phase, to make precursor composite oxalate particles. The precursor particles obtained in the VA-10 system were mainly 20−60 nm in size, together with a smaller amount of submicron-sized spherical particle, and were much smaller than those prepared in homogeneous aqueous solution (1−10 μm in size). The molar composition of the particles, {M/(Y+Yb+Er)}p (M = Yb or Er), prepared in the VA-10 and DTMBPA systems, was almost proportional to that of the feed external solution, {M/(Y+Yb+Er)}f. Calcin...

A desulfurization and denitrogenation process for light oils has been investigated based on the chemical oxidation of sulfur- and nitrogen-containing compounds using hydrogen peroxide and acetic acid as oxidizing agent. Sulfur and nitrogen compounds, when dissolved in n-tetradecane and xylene, were oxidized under moderate conditions and were removed successfully. By use of this basic process, although nitrogen content of actual light oils was reduced to

A desulfurization process for light oils has been investigated, based on the formation and subsequent adsorption of N-tosylsulfimides, produced by the reaction of the sulfur compounds in the light oils, with chloramine T (sodium N-chloro-p-toluenesulfonamide). Dibenzothiophenes (DBTs) in light oils are converted, by the reaction with chloramine T dissolved in methanol, to form the corresponding sulfimides and are removed into the methanol under moderate conditions, whereas benzothiophenes (BTs) gave rise to the corresponding chlorine-adduct products, on their unsaturated bond. The sulfimides of alkyl-substituted DBTs, formed during the reaction, remained in the resulting light oil, such that the deep desulfurization (0.05 wt %) failed to achieve. These compounds however were removed successfully by the addition of aluminum oxide adsorbent and the sulfur concentration of the light oil was decreased to less than 0.05 wt %. The desulfurization of high-aromatic-content light oil is relatively more difficult, because the aromatic hydrocarbons are chlorinated by reaction with chloramine T, proceeding competitively with chlorination of the sulfur compounds.

A desulfurization process for light oils, based on photocatalytic oxidation of sulfur-containing compounds using TiO2 and an oil/acetonitrile two-phase extraction, has been investigated. Dibenzothiophenes (DBTs), when dissolved in acetonitrile, are oxidized by photoirradiation at wavelengths λ > 320 nm in the presence of TiO2, to form the corresponding sulfoxides and sulfones, which do not distribute into the non-polar light oil owing to their high polarity. When light oil and acetonitrile are mixed and photoirradiated in the presence of TiO2, the sulfur compounds are extracted successively and photooxidized in acetonitrile. By this means, deep desulfurization is achieved: the sulfur content of light oil being reduced from 0.18 to less than 0.05 wt%. The present process, however, has a difficulty in the desulfurization of high-aromatic-content light oils.

A desulfurization process for light oil has been investigated based on chemical oxidation of sulfur-containing compounds over Ti-containing molecular sieve catalysts. Sulfur compounds, when dissolved in n-tetradecane (model light oil), were oxidized to the corresponding sulfoxides and sulfones in the presence of the catalysts and H2O2, and were removed successfully from the oil. However, by use of this basic process, the sulfur concentration of actual light oil failed to be reduced to the required deep desulfurization level (0.05 wt%). This is because alkyl-substituted sulfoxides and sulfones, produced during the process, are adsorbed on the surface of the catalyst, thus decreasing the catalytic activity. When desulfurization was carried out in the presence of polar acetonitrile solvent, the adsorption of these compounds onto the catalyst was suppressed significantly and the deep desulfurization was achieved successfully. In this process, the denitrogenation of light oil also proceeded effectively. The catalyst recovered showed no decrease in the catalytic activity and could be reused for further desulfurization and denitrogenation of light oil.

The denitrogenation behavior of several model nitrogen compounds has been investigated during a novel desulfurization and simultaneous denitrogenation process based on alkylation using CH 3 I and AgBF 4 (alkylating agents) and subsequent precipitation of the resulting materials. The denitrogenation reactivities obtained for basic nitrogen compounds (aniline, pyridine, quinoline, and acridine) dissolved in xylene solution were compared to those for neutral compounds (pyrrole, indole, and carbazole). The basic compounds and carbazole were removed from xylene by reaction with the alkylating agents as precipitates of the corresponding N-methylated tetrafluoroborates, whereas pyrrole and indole produced insoluble polymerized materials on their unsaturated bonds. It was found that the denitrogenation reactivities lie in the order pyridine > aniline > acridine > quinoline for basic compounds and pyrrole > indole > carbazole for neutral compounds. Semiempirical MO calculations show that the reactivities of the basic compounds depend on the electron density on the π orbital for the nitrogen atom lying perpendicular to the plane of the molecules.

The denitrogenation behavior of light oils, when occurring during a novel desulfurization process based on alkylation and a subsequent precipitation method, using the alkylating agents (CH3I and AgBF4), has been investigated. Denitrogenation results, obtained for three model nitrogen compounds (aniline, indole, and carbazole) in a xylene solution, were compared with the results for three light oils, of differing nitrogen, sulfur, and aromatic concentration. The nitrogen compounds in the light oils were found to be N-methylated by reaction with the alkylating agents, such that they were removed as precipitates under moderate conditions. By use of this process, the nitrogen contents of all of the light oils were reduced successfully to less than 20% of the corresponding feed concentration, thus demonstrating that the present process is satisfactory for the simultaneous denitrogenation of light oils combined with desulfurization. Although the denitrogenation of aniline and indole compounds from the light oil...

The simultaneous removal of sulfur- and nitrogen-containing compounds from vacuum gas oil (VGO), based on alkylation and a subsequent precipitation method using alkylating agents (CH3I and AgBF4), has been investigated. Desulfurization and denitrogenation reactivities for various compounds in VGO have been studied by means of field ionization−mass spectrometry (FI−MS) and gas chromatography−atomic emission detection (GC−AED), respectively. The sulfur and nitrogen compounds in the VGO were found to be methylated by the addition of the alkylating agents under moderate conditions and were removed successfully as the precipitates of the corresponding S-methylsulfonium and N,N-dimethylcarbazolium tetrafluoroborates. By this means, the sulfur and nitrogen concentrations of the VGO were reduced simultaneously to less than 0.1% and 7.0% of the corresponding feed values, in the presence of a 20-fold molar excess of CH3I and a 10-fold molar excess of AgBF4, respectively, based on the initial sulfur concentration of...

Recent developments in an advanced liquid−liquid extraction system for the separation of metal ions by combining a modification or chemical reaction of the metal species in the aqueous and organic phases demonstrate considerable potential. Possible techniques for the chemical conversion of aqueous-phase metal species include redox reactions for the metal ions, masking effects through the addition of water-soluble complexing agents, and complexing reactions with salting-out agents. For the conversion of organic-phase metal species, a synergistic effects through the addition of additional extractants and redox reactions for the extracted species are also useful. The separation of metal ions is effectively improved by the introduction of such chemical reactions to the extraction system.

A desulfurization process, based on the formation and subsequent precipitation of S-alkylsulfonium salts using alkylating agents (CH3I and AgBF4), has been applied to the desulfurization of catalytic-cracked gasoline (CCG). The desulfurization reactivity of each sulfur compound (thiol, disulfide, benzothiophene, tetrahydrothiophene, and thiophenes) in n-decane solution, as a model gasoline, was compared with that obtained from actual CCG. The sulfur compounds in CCG are methylated by the addition of the alkylating agents under moderate conditions and are removed as the precipitates of the corresponding S-alkylsulfonium salts. By employing this new process, the sulfur content of the CCG was decreased from 100 ppm to less than 30 ppm. The benzothiophene in CCG was found to be the most difficult compound to desulfurize, whereas the thiophenes were the most difficult compounds for the model gasoline. Although the olefin concentration was decreased significantly following desulfurization, the resulting CCG dem...

A novel desulfurization process for light oils has been investigated, based on the precipitation of S-alkylsulfonium salts produced by the reaction of sulfur-containing compounds with alkylating ag...

乳化液膜（W/0/Wエマルション）系を用いる微粒子材料の調製に関する研究を行った．乳化液膜系において，反応資材である外水相中の金属イオンは，抽出剤（カチオンキャリア）を含む液膜相に抽出され，さらに内水相に逆抽出されてサブミクロン-ミクロンサイズのしゅう酸塩，炭酸塩やリン酸塩微粒子を形成した．ケーススタディとして，希土類金属の球形しゅう酸塩微粒子，中空構造をもつ球形炭酸カルシウム微粒子ならびにリン酸カルシウム微粒子の調製，さらに複合微粒子としてSr-Pb複合しゅう酸塩微粒子，針状CoフェライトとNiフェライト微粒子ならびに球形希土類酸化物蛍光体微粒子の調製を行い，これらの研究を通して，特殊なミクロ反応場としての内水相の性質と機能を明らかにした．

The simultaneous removal of sulfur- and nitrogen-containing compounds from vacuum gas oil (VGO), based on the combination of UV irradiation and liquid−liquid extraction using an oil/acetonitrile two-phase system, has been investigated. Detailed desulfurization and denitrogenation reactivities for the various compounds in VGO have also been studied by means of field ionization mass spectrometry (FI-MS) and gas chromatography with atomic emission detection (GC-AED), respectively. When VGO and acetonitrile are mixed and photoirradiated, the sulfur and nitrogen compounds in the VGO are distributed into the acetonitrile phase and photodecomposed there to form highly polarized compounds, which do not distribute into the lower-polarity VGO. The successive removal of these compounds from VGO to acetonitrile can therefore be carried out under moderate conditions, such that the sulfur and nitrogen contents for the VGO are decreased simultaneously to less than 1% of the feed values. FI-MS and GC-AED analyses reveal ...

The photoreductive stripping of cobalt from hydroxyoxime extractants was investigated, employing 2-hydroxy-5-nonylacetophenone oxime (LIX-84I) and 2-hydroxy-5-nonylbenzophenone oxime (LIX-65N) as extractants, n-dodecane as the diluent, and a halogen lamp as the light source. The stripping of cobalt is barely achieved by conventional stripping, in this extraction system, because of the oxidation of the cobalt-hydroxyoxime complex by electron attraction with the O 2 molecule. The stripping of cobalt is, however, substantially improved by photoirradiation using light of visible radiation wavelength. The organic solution obtained following photoirradiation can be reused for repeated extraction and photoreductive stripping processing.