Decomposition of Benzene in Air in a Plasma Reactor: Effect of Reactor Type and Operating Conditions

The decomposition of benzene was carried out in two types of plasma reactors packed with BaTiO₃ pellets: one reactor had two stainless steel electrodes (SUS reactor), and the other reactor had a glass layer between two concentric electrodes (GL reactor). The decomposition efficiency and the suppression of formation of N₂O and NO_x were greater in the GL reactor than in the SUS reactor. In contrast, the suppression of O₃ formation and the oxidation to CO_x in the SUS reactor were superior to those in the GL reactor. The effect of wa eform and frequency of applied ac power was in estigated for each reactor.     

Methane Decomposition in a Barium Titanate Packed-Bed Nonthermal Plasma Reactor

The behavior of lattice oxygen species of the ferroelectric material during methane oxidation was investigated using a nonthermal plasma reactor packed with BaTiO ₃ pellets. Lattice oxygen species in BaTiO ₃ play an important role in the formation of N ₂ O and the oxidation of CH ₄ . The oxidation products such as CO and CO ₂ were formed from independent reaction pathways. Lattice oxygen species were able to preferentially oxidize the carbon species deposited on the pellet surface into CO. Also, N ₂ O and NO _x were independently formed in the N ₂–O ₂ reaction, suggesting that different oxygen species give N ₂ O and NO _x. N ₂ O was produced by the oxidation of molecular nitrogen with lattice oxygen species.     

Sulfur-rich CpCo(dithiolene) complexes: Isostructural or non-isostructural couples of CpCo(III) with CpNi(III) dithiolene complexes

Eight new sulfur-rich [CpCo(dithiolene)] complexes were synthesized from [Zn(dmit)₂]²⁻ as a starting material. The structures, electrochemical behavior and electronic absorption spectra of the sulfur-rich [CpCo(S₂C₂S₂Y)] complexes could be compared with the early data of analogous Ni complexes. [CpCo(pddt)] (Y = -(CH₂)₃-), [CpCo(dpdt)] (Y = -CH₂C(CH₂)CH₂-), [CpCo(bddt)] (Y = -(CH₂)₄-), [CpCo(dtdt)] (Y = -CH₂SCH₂-) and [CpCo(poddt)] (Y = -CH₂C(O)CH₂-) crystallized in all isostructural with the corresponding paramagnetic [CpNi(dithiolene)] complexes, but [CpCo(dmid)] (Y = CO), [CpCo(dddt)] (Y = -(CH₂)₂-) and [CpCo(F₂pddt)] (Y = -CH₂CF₂CH₂-) crystallized in non-isostructural with them. These molecules are associated with intermolecular short S?S contacts in the crystals. [CpCo(F₂pddt)] did not show any remarkable S?S contacts but indicated interesting fluorine segregation and Cp?Cp face-to-face interactions. Redox potentials of [CpCo(dithiolene)] complexes were obtained with the cyclic voltammetry measurements and dimerized by electrochemical oxidations. Electronic absorption spectra of [CpCo(dithiolene)] complexes showed visible absorption in the range of 585-701 nm as lowest energy wavelengths (? = 9800-11,800 M⁻¹ cm⁻¹) in solutions, and they were higher energy than those of [CpNi(dithiolene)] complexes (near-IR).     

Asymmetric synthesis of bicyclo[n.1.0]alkanes by the enantioselective 1,3-CH insertion reaction of chiral magnesium carbenoids

Treatment of enantiomerically pure 1-chlorovinyl p-tolyl sulfoxides, derived from cyclic ketones and (R)-chloromethyl p-tolyl sulfoxide, with the lithium enolate of tert-butyl carboxylates gave adducts in quantitative yields as single diastereomers. The adducts were treated with i-PrMgCl in toluene to afford optically active bicyclo[n.1.0]alkanes bearing a tert-butyl carboxylate moiety in up to 99% enantiomeric excess through the enantioselective 1,3-CH insertion reaction of the generated chiral magnesium carbenoids. This is the first example of the enantioselective 1,3-CH insertion reaction of magnesium carbenoid.     

Effect of industrial water components on thermal stability of nitrocellulose

In order to prevent the spontaneous ignition of nitrocellulose (NC), NC is stabilized by washing with industrial water in its synthesis process. However, there is a possibility that the components in industrial water contribute to the thermal stability of NC. In this way, the purpose of this study is to clarify the effect of industrial water components on the thermal stability of NC. In experiments, a heat flux calorimeter was used to observe the thermal behavior of NC with the residue of vaporized industrial water. The induction period of heat release of NC with 2-mass% residues was approximately 2–5 h shorter than that of NC alone whose induction period was observed at 7 h. Those results indicate that the residue destabilized NC. On the other hand, when the additive amount of the residue was increased, the induction period gradually increased as well. Based upon these results, we assume that inorganic salts contributing to stabilization and destabilization competitively coexist in the industrial water components. The same thermal analysis was performed on NC with CaCO₃, CaSO₄, CaCl, ZnSO₄, NaCl, and CuCl. Those salts are predicted to exist in the industrial water. In the results, the induction period of NC with 2-mass% CaCO₃ was approximately 15-h longer than that of NC alone, while the induction period with the inorganic salts CaSO₄, CaCl, ZnSO₄, NaCl, and CuCl was 4–5-h shorter. Therefore, when the industrial water components accumulate in NC, the destabilization by inorganic salts such as CaSO₄, CaCl, ZnSO₄, NaCl, and CuCl and the stabilization by compounds such as CaCO₃ are thought to countervail against each other.     

The first example of regiospecific magnesium carbenoid 1,3-CH insertion: its mechanism and stereochemistry

Addition reaction of two geometrical isomers of 1-chlorovinyl p-tolyl sulfoxides, derived from unsymmetrical ketones and chloromethyl p-tolyl sulfoxide, with lithium enolate of tert-butyl acetate gave single isomers of the adduct, respectively. Treatment of each diastereomer with i-PrMgCl resulted in the formation of magnesium carbenoids. Highly regiospecific 1,3-CH insertion reaction was found to take place from the magnesium carbenoids to afford cyclopropanes in high yields. Stereochemistry of the adducts, reaction mechanism, and origin of the regiospecificity are discussed.     

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.     

Synthesis and Applications of (ONO Pincer)Ruthenium‐Complex‐Bound Norvalines

Two (ONO pincer)ruthenium‐complex‐bound norvalines, Boc?[Ru(pydc)(terpy)]Nva?OMe ( 1 ; Boc=tert‐butyloxycarbonyl, terpy=terpyridyl, Nva=norvaline) and Boc?[Ru(pydc)(tBu‐terpy)]Nva?OMe ( 5 ), were successfully synthesized and their molecular structures and absolute configurations were unequivocally determined by single‐crystal X‐ray diffraction. The robustness of the pincer Ru complexes and norvaline scaffolds against acidic/basic, oxidizing, and high‐temperature conditions enabled us to perform selective transformations of the N‐Boc and C?OMe termini into various functional groups, such as alkyl amide, alkyl urea, and polyether groups, without the loss of the Ru center or enantiomeric purity. The resulting dialkylated Ru‐bound norvaline, n‐C₁₁H₂₃CO?l ‐[Ru(pydc)(terpy)]Nva?NH‐n‐C₁₁H₂₃ (l ‐ 4 ) was found to have excellent self‐assembly properties in organic solvents, thereby affording the corresponding supramolecular gels. Ru‐bound norvaline l ‐ 1 exhibited a higher catalytic activity for the oxidation of alcohols by H₂O₂ than parent complex [Ru(pydc)(terpy)] ( 11 a ).     

Detection of environmental chemicals by SPR assay using branched cyclodextrin as sensor ligand

We obtained the association constants Ka of estrogen (E2) and environmental chemicals by the surface plasmon resonance (SPR) assay using the immobilized mono-6-O-α-maltosyl-β-CD (G₂βCD) compared with the immobilized β-CD and the immobilized estrogen receptor (ER). The association behavior of G₂βCD was shown as a ER model compound. The calibration curve was determined by the initial rate of association depending on the various concentrations, and the minimum detectable concentrations in the order of parts per billion were calculated. The SPR assay has advantages that the pre-treatment of the sample is not necessary and the immobilized ligand is stable and useful for the repeated measurement.