Photothermal Oxidation of Cinnamyl Alcohol with Hydrogen Peroxide Catalyzed by Gold Nanoparticle/Antimony-Doped Tin Oxide Nanocrystals

Gold nanoparticles with different mean sizes were formed on antimony-doped tin oxide nanocrystals by the temperature-varied deposition-precipitation method (Au/ATO NCs). Au/ATO NCs possess strong absorption in the near-infrared region due to Drude excitation in addition to the localized surface plasmon resonance (LSPR) of AuNPs around 530 nm. Au/ATO NCs show thermally activated catalytic activity for the oxidation of cinnamyl alcohol to cinnamaldehyde by hydrogen peroxide. The catalytic activity increases with a decrease in the mean Au particle size (d_Au) at 5.3 nm≤d_Au≤8.2 nm. Light irradiation (λ_ex >660 nm, ∼0.5 sun) of Au/ATO NCs increases the rate of reaction by more than twice with ∼95 % selectivity. Kinetic analyses indicated that the striking enhancement of the reaction stems from the rise in the temperature near the catalyst surface of ∼30 K due to the photothermal effect of the ATO NCs.     

Nuclear Quadrupole Coupling Constants of Chlorine and Microwave Spectrum, Structure, and ab Initio Calculation of 1-Chloro-1,1,2-trifluoroethane

The microwave spectrum of the ³⁵Cl and ³⁷Cl isotopic species of 1-chloro-1,1,2-trifluoroethane (HCFC-133b) has been investigated in the frequency region 10 to 50 GHz using a Stark modulation microwave spectrometer. A pulsed jet Fourier transform microwave spectrometer was also used for the measurement of hyperfine splittings. A least-squares analysis of the observed b-type Q- and R-branch transition frequencies gave rotational and centrifugal distortion constants and components of the chlorine nuclear quadrupole coupling constant tensors in the principal axes system as follows: A=4625.161 (3) MHz, B=2004.127 (2) MHz, C=1875.813 (2) MHz, Δ_J=0.144 (9) kHz, Δ_JK=1.0748 (8) kHz, Δ_K=1.57 (1) kHz, δ_J=0.01376 (4) kHz, δ_K=−0.146 (4) kHz, χ_aa=−57.958 (10) MHz, χ_bb=21.231 (11) MHz, and χ_cc=36.727 (11) MHz for ³⁵ClCF₂CH₂F species, and A=4607.684 (6) MHz, B=1960.565 (2) MHz, C=1834.823 (2) MHz, Δ_J=0.106 (7) kHz, Δ_JK=1.022 (3) kHz, Δ_K=1.48 (1) kHz, δ_J=0.0142 (2) kHz, δ_K=−0.18 (2) kHz, χ_aa=−46.268 (11) MHz, χ_bb=17.319 (13) MHz, and χ_cc=28.950 (13) MHz for ³⁷ClCF₂CH₂F species. The structural parameters are calculated from the observed six rotational constants by assuming the partial structure of ab initio calculation. The electronic properties of the C-Cl bond are evaluated from the observed nuclear quadrupole constants of chlorine. These molecular properties are compared with those of other related molecules.     

Kinetic study of the crosslinking reaction of 1,2‐polybutadiene with dicumyl peroxide in the absence and presence of vinyl acetate

The crosslinking reaction of 1,2-polybutadiene (1,2-PB) with dicumyl peroxide (DCPO) in dioxane was kinetically studied by means of Fourier transform near-infrared spectroscopy (FTNIR). The crosslinking reaction was followed in situ by the monitoring of the disappearance of the pendant vinyl group of 1,2-PB with FTNIR. The initial disappearance rate (R₀) of the vinyl group was expressed by R₀ = k[DCPO]^0.8[vinyl group]^−0.2 (120 °C). The overall activation energy of the reaction was estimated to be 38.3 kcal/mol. The unusual rate equation was explained in terms of the polymerization of the pendant vinyl group as an allyl monomer involving degradative chain transfer to the monomer. The reaction mixture involved electron spin resonance (ESR)-observable polymer radicals, of which the concentration rapidly increased with time owing to a progress of crosslinking after an induction period of 200 min. The crosslinking reaction of 1,2-PB with DCPO was also examined in the presence of vinyl acetate (VAc), which was regarded as a copolymerization of the vinyl group with VAc. The vinyl group of 1,2-PB was found to show a reactivity much higher than 1-octene and 3-methyl-1-hexene as model compounds in the copolymerization with VAc. This unexpectedly high reactivity of the vinyl group suggested that an intramolecular polymerization process proceeds between the pendant vinyl groups located on the same polymer chain, possibly leading to the formation of block-like polymer. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4437–4447, 2004     

Collection of iron(III) from homogeneous aqueous solutions on membrane filters using Chromazurol B with Triton X-100.

A membrane filtration method was examined concerning the effective collection of iron(III) from a homogeneous aqueous solution with Chromazurol B (CAB), one of the triphenylmethane dyes, as a precipitating reagent in the presence of a non-ionic surfactant, polyethylene glycol mono[4-(1,1,3,3-tetramethylbutyl)phenyl]ether (Triton X-100). A formed blue Fe(III)-CAB complex was collected as a precipitate on a membrane filter by filtration under suction from a homogeneous aqueous solution in the pH range over about 2. The original solution was prepared at a concentration ratio of CAB to Fe(III) of to 10, and that of Triton X-100 to CAB of 10 to 100. It was then adjusted to a pH value of between 1.0 and 6.5. A linear relationship (r = 0.999) was obtained between the initial concentration and the found one of Fe(III) in the range of 2.0 x 10(-5) to 4.0 x 10(-4) mol dm(-3) at a fixed concentration ratio of CAB to Fe(III) of 3 and that of Triton X-100 to CAB of 20. This membrane filtration with CAB and Triton X-100 may be utilized for the separation of Fe(III) as a background species.     

Comments on the bremsstrahlung cross section formula using exact electron-distorted wave functions

Rozics and Johnson's formula is examined and its inconsistency is pointed out.     

Mesorbitolina (Cretaceous larger foraminifera) from the Yezo Group in Hokkaido,Japan and its stratigraphic and paleobiogeographic significance

In this paper, we describe an Aptian (Early Cretaceous) larger foraminiferal species Orbitolina (Mesorbitolina) parva from the limestone olistoliths in the lower part of the Yezo Group in the Yubari–Ashibetsu area, central Hokkaido and from limestone pebbles in the lowermost part of the Yezo Group in the Nakagawa area, northern Hokkaido. This is the first report of this species from the circum-North Pacific regions. Based on its occurrences, the shallow-marine carbonates, re-deposited in the lower part of the Yezo Group, are precisely assigned in age to the Late Aptian. Comparison of the lower part of the Yezo Group in central and northern Hokkaido indicates differences of the Aptian–Albian depositional history between the two areas. This study reveals that after Late Aptian, Mesogean key taxa (typical Cretaceous Tethyan biota) demised in the Northwest Pacific.     

A Monte Carlo method for high dimensional integration

Summary A new method for the numerical integration of very high dimensional functions is introduced and implemented based on the Metropolis' Monte Carlo algorithm. The logarithm of the high dimensional integral is reduced to a 1-dimensional integration of a certain statistical function with respect to a scale parameter over the range of the unit interval. The improvement in accuracy is found to be substantial comparing to the conventional crude Monte Carlo integration. Several numerical demonstrations are made, and variability of the estimates are shown.     

Stability of a system of Volterra integro-differential equations

Using new and known forms of Lyapunov functionals, this paper proposes new stability criteria for a system of Volterra integro-differential equations.     

Catalytic asymmetric intramolecular hydroamination of aminoalkenes

Asymmetric intramolecular cyclization of aminoalkenes was catalyzed by a catalytic amount of n-butyllithium, diisopropylamine, and a newly designed chiral bisoxazoline in toluene to produce kinetically controlled exo-cyclized amines with up to 91% ee quantitatively.     

A Monte Carlo method for an objective Bayesian procedure

This paper describes a method for an objective selection of the optimal prior distribution, or for adjusting its hyper-parameter, among the competing priors for a variety of Bayesian models. In order to implement this method, the integration of very high dimensional functions is required to get the normalizing constants of the posterior and even of the prior distribution. The logarithm of the high dimensional integral is reduced to the one-dimensional integration of a cerain function with respect to the scalar parameter over the range of the unit interval. Having decided the prior, the Bayes estimate or the posterior mean is used mainly here in addition to the posterior mode. All of these are based on the simulation of Gibbs distributions such as Metropolis' Monte Carlo algorithm. The improvement of the integration's accuracy is substantial in comparison with the conventional crude Monte Carlo integration. In the present method, we have essentially no practical restrictions in modeling the prior and the likelihood. Illustrative artificial data of the lattice system are given to show the practicability of the present procedure.