Thermal hazard evaluation of lauroyl peroxide mixed with nitric acid.

Many thermal runaway incidents have been caused by organic peroxides due to the peroxy group, -O-O-, which is essentially unstable and active. Lauroyl peroxide (LPO) is also sensitive to thermal sources and is incompatible with many materials, such as acids, bases, metals, and ions. From the thermal decomposition reaction of various concentrations of nitric acid (HNO3) (from lower to higher concentrations) with LPO, experimental data were obtained as to its exothermic onset temperature (T0), heat of decomposition (ΔHd), isothermal time to maximum rate (TMRiso), and other safety parameters exclusively for loss prevention of runaway reactions and thermal explosions. As a novel finding, LPO mixed with HNO3 can produce the detonation product of 1-nitrododecane. We used differential scanning calorimetry (DSC), thermal activity monitor III (TAM III), and gas chromatography/mass spectrometer (GC/MS) analyses of the reactivity for LPO and itself mixed with HNO3 to corroborate the decomposition reactions and reaction mechanisms in these investigations.

Mass spectra of 3,3-difluoro-1-halo-2-arylcyclopropenes.

The electron ionization (EI) mass spectra of a series of 3,3-difluoro-1-halo-2-arylcyclo- propenes (1, 2) give the fragments [M-X](+) (X: Br, Cl) as the base peaks. A comparison of tandem mass spectrometry (MS/MS) profiles of the m/z 151 ions recorded from compounds 1 and 2 and 3-bromo-3,3-difluoro-1-phenylcyclopropyne (5), 1,1,2,2-tetrafluoro-3-phenyl- cyclopropane (6), 1,1,2,2-tetrafluoroindane (7), and 2,3,3-trifluoroindene (8) suggested that the structure of the derived [M-X](+) fragment ion is more likely that of a substituted cyclopropenium ion. The results from calculations using the density functional theory (DFT) method support this MS/MS analysis.

[Measurement of plasma mast cell carboxypeptidase and chymase levels in children with allergic diseases].

OBJECTIVE: To evaluate the roles of plasma mast cell carboxypeptidase and chymase in the diagnosis of allergic diseases by measuring the contents of both in children. METHODS: A total of 59 children with allergic diseases and 53 healthy children were recruited into the study. Plasma levels of mast cell carboxypeptidase and chymase were measured using ELISA. RESULTS: The plasma levels of mast cell carboxypeptidase and chymase in children with allergic children were 1.089 ± 0.752 ng/mL and 0.905(0.375-2.318) ng/mL, respectively, which were significantly higher than those in healthy children [0.593 ± 0.380 ng/mL and 0.454 (0.097-1.077) ng/mL respectively; P<0.05]. There was a significantly positive correlation between plasma mast cell carboxypeptidase and chymase levels in children with allergic diseases (r=0.684, P<0.01). CONCLUSIONS: Plasma levels of mast cell carboxypeptidase and chymase increase in children with allergic diseases, suggesting that mast cell carboxypeptidase and chymase may serve as the indexes for the diagnosis of allergic diseases.