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.     

Enthalpies of mixing of ethanol solution of chiral limonenes at 298.15 K

Enthalpies of mixing of ethanol solution of R- and S-enantiomers of limonene in large concentration have been measured at 298.15 K. The enthalpies of mixing were negligibly small for all concentrations. Enthalpies of mixing showed negative in less than 30 mol%, but positive in more than the high concentration of limonenes. The heterochiral solutions were more stable than each of the homochiral solutions in dilute solutions. The concentration dependence on enthalpies of mixing in dilute concentration of less than 10 mol% was much sharper in inclination than the dense solutions limonene.     

Excess enthalpies of binary mixtures of <Emphasis Type="Italic">ortho</Emphasis>-, <Emphasis Type="Italic">meta</Emphasis>-, and <Emphasis Type="Italic">para</Emphasis>-structural isomers

The excess molar enthalpies of 8 binary mixtures for the o-, m-, and p-isomers of fluoroiodobenzene, fluoromethoxybenzene, bromofluorobenzene, chlorofluoro-benzene, difluorobenzene, fluoromethylbenzene, fluoronitrobenzene, and aminofluoro-benzene were measured at 298.15 K. The changes of the measured enthalpies were very small. The experimental results revealed that the isomers containing two electron-acceptor groups showed the most positive excess enthalpy change, while isomers containing both one electron donor and one electron acceptor group, such as aminofluorobenzene, showed more stable and always the most negative results.     

Preparation and certification of arsenate [As(V)] reference material, NMIJ CRM 7912-a

Arsenate [As(V)] solution reference material, National Metrology Institute of Japan (NMIJ) certified reference material (CRM) 7912-a, for speciation of arsenic species was developed and certified by NMIJ, the National Institute of Advanced Industrial Science and Technology. High-purity As₂O₃ reagent powder was dissolved in 0.8 M HNO₃ solution and As(III) was oxidized to As(V) with HNO₃ to prepare 100 mg kg^-1 of As(V) candidate CRM solution. The solution was bottled in 400 bottles (50 mL each). The concentration of As(V) was determined by four independent analytical techniques—inductively coupled plasma mass spectrometry, inductively coupled plasma optical emission spectrometry, graphite furnace atomic absorption spectrometry, and liquid chromatography inductively coupled plasma mass spectrometry—according to As(V) calibration solutions, which were prepared from the arsenic standard of the Japan Calibration Service system and whose species was guaranteed to be As(V) by NMIJ. The uncertainties of all the measurements and preparation procedures were evaluated. The certified value of As(V) in the CRM is (99.53 ± 1.67) mg kg^-1 (k = 2).     

Synthesis of β‐Methoxyacrylate Natural Products Based on Box‐PdII‐Catalyzed Intermolecular Methoxycarbonylation of Alkynoles

Bis(oxazoline)‐palladium(II) catalyzed carbonylation of homopropargyl alcohols afforded acyclic methoxyacrylate 2 and 6‐membered lactone 3a , 3b , 3d , 3e , 3f , 3g , 3h , 3i , 3j , 3k in good combined yield. In the case of propargyl alcohols, 5‐membered lactones 3p , 3q , 16 were obtained in moderate yields. The one‐pot synthesis of kawa lactones 3a , 3r , 3s and formal synthesis of dihydroxycystothiazole A and dihydroxycystothiazole C are presented. To elucidate the stereochemistry of (+)‐annularin G and (?)‐annularin H, the first asymmetric syntheses of these natural products were achieved.     

4-(cyanomethyl)anilinium perchlorate: a new displacive-type molecular ferroelectric

A new organic ferroelectric compound, 4-(cyanomethyl)anilinium perchlorate, proceeds a second-order phase transition from a paraelectric phase (P2(1)/m) to a ferroelectric phase (P2(1)) at 184 K. A perfect ferroelectric hysteresis loop was observed even at 10 KHz. It is the first example of a molecule-based organic ferroelectric whose polarization can be switched at such a high frequency. The temperature dependent second harmonic generation effect shows that the second-order nonlinear coefficient is nearly zero above T(c) and proportional to the spontaneous polarization below T(c), suggesting the occurrence of symmetry breaking, in good agreement with crystal structural determination. The origin of ferroelectricity was ascribed to the displacements of -NH(3)(+) cations and ClO(4)(-) anions from the symmetric positions including a small part of the order-disorder behaviors of the ClO(4)(-) anions.     

Octave-spanning carrier-envelope phase stabilized visible pulse with sub-3-fs pulse duration

The visible second harmonic of the idler output from a noncollinear optical parametric amplifier was compressed using adaptive dispersion control with a deformable mirror. The amplifier was pumped by and seeded in the signal path by a common 400 nm second-harmonic pulse from a Ti:sapphire regenerative amplifier. Thus, both the idler output and the second harmonic of the idler were passively carrier-envelope phase stabilized. The shortest pulse duration achieved was below 3 fs.     

Synthesis and healing properties of poly(arylether sulfone)–poly(alkylthioether) multiblock copolymers containing disulfide bonds

Thermoplastic elastomers composed of soft and hard segments are important elastic and processable synthetic polymers. The microphase‐separated soft domains show low glass transition temperature and possess sufficient chain mobility at room temperature. In this study, we report the synthesis and healing properties of multiblock copolymers containing disulfide bonds as dynamic covalent bonds. The multiblock copolymers composed of poly(arylether sulfone) and poly(alkylthioether) segments were synthesized by oxidative coupling polymerization of the corresponding thiol‐terminated oligomers. Atomic force microscopy phase images, differential scanning calorimetry, and dynamic mechanical analysis curves indicated the microphase‐separated morphology of the multiblock copolymer. Self‐healing properties of the polymer were evaluated by changes in the elongation at break of the cut/adhered samples. The elongation recovery increased with UV irradiation time, and the multiblock copolymer showed a 93% recovery after UV irradiation for 5 h. The healing efficiency induced by UV irradiation, determined by subtracting the recovery without UV irradiation, was calculated to be 51%. According to the UV spectra and solubility changes after UV irradiation, the main healing factor in this study was the crosslinking reactions caused by thiyl radicals generated from UV irradiation instead of disulfide exchange reactions. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3545–3553