HPLC–MS determination of the oxidation products of the reaction between α- and β-pinene and OH radicals

Biogenic non-methane hydrocarbons such as isoprene, alpha-pinene, and beta-pinene, are emitted by forests in very large quantities. To evaluate the role of alpha- and beta-pinene and their contribution to the global production of trace gases and especially aerosol precursors, a study of the oxidation mechanism of alpha- and beta-pinene with hydroxyl radicals must be conducted.The degradation products of both monoterpenes with hydroxyl radicals were identified and quantified in a fast-flow reactor. The products were collected on a liquid-nitrogen trap coated with a 2,4-DNPH solution to which two internal standards (benzaldehyde-2,4-DNPH and tolualdehyde-2,4-DNPH) had been added. The collection method was based on the in situ conversion of aldehyde and/or ketone compounds to their 2,4-dinitrophenylhydrazone derivatives. The derivatives were analyzed by HPLC-MS using APCI(-). TIC chromatograms and mass spectral data for the various oxidation products are presented.For alpha-pinene, pinonaldehyde is the most important degradation product, with smaller amounts of acetone, formaldehyde, campholenealdehyde, and acetaldehyde. For beta-pinene, nopinone and formaldehyde are the most abundant products, of almost equal importance, whereas acetone and acetaldehyde are minor compounds.     

Benzo- and indoloquinolizine derivatives. III. Synthesis and structural assignments of 4b,5,6,7,8,8a,10,11-octahydro-15bH-tribenzo-[a,c,h]quinolizine (4b,5,6,7,8,8a,10,11–octahydro-15bH-isoquino[2,1-f] phenanthridine)

Starting from either trans-2-phenylcyclohexylamine or the cis isomer, two epimers of 4b,5,6,7,8,8a,10,11-Octahydro-15bH-tribenzo[a,c,h]quinolizine have been synthesized. The four possible diastereoisomers of this compound were obtained by reduction of the enamine 5,6,7,8,10,11-hexahydro-15bH-tribenzo[a,c,h]quinolizine. Configuration and conformation are discussed by use of ir, 67.88 MHz cmr and 270 MHz pmr spectroscopy.     

ortho-metallation reactions involving some triphenyl phosphite complexes of osmium

Osmium triphenylphosphine complexes, OsH₄(PPh₃)₃, OsH₂ (CO)(PPh₃)₃ and OsHCl(CO)(PPh₃)₃ react with triphenyl phosphite in boiling organic solvents to yield triphenyl phosphite derivatives which subsequently undergo ortho-metallation reactions.     

Flash photolysis studies of the reaction of NH2 radicals with NO

The kinetics of the reaction NH₂ + NO → N₂ + H₂O were studied, using a conventional flash photolysis system. A value of k₁ = (1.1 ± 0.2) × 10¹⁰ & mole^?1 s^?1 was obtained at room temperature and in the pressure range 2–700 torr in the presence of nitrogen. A slight negative temperature coefficient was observed between 300 and 500 K, equivalent to a negative activation energy of 1.05 ± 0.2 kcal mole^?1.     

INDUCTION OF FREE RADICALS IN DNA BY PROFLAVINE AND VISIBLE LIGHT: INFLUENCE OF OXYGEN AND IONIC STRENGTH

Abstract —The photosensitization of native DNA is observed as an induction of free radicals in the DNA moiety of proflavine-DNA complexes. The intensity of the electron paramagnetic resonance spectra (at 77 K) is a measure of the number of free radicals present in frozen solutions of DNA-proflavine complexes after irradiation with visible light (Λ > 320 nm). In the absence of O₂, the photosensitization is significant but very low; it increases slightly with increasing NaCl ionic strength; it appears to be due to intercalated dye molecules and the qualitative analysis of the spectra obtained shows that mainly thymidine is involved. The reaction measured after saturation with O₂ is the same as the reaction in air but is quantitatively higher; the free radicals observed are peroxides. This induction of free radicals appears to be due to the intercalated dye molecules, each molecule acting independently. The important observation is a very sharp and large (around a hundred-fold) increase in the photosensitizing efficiency of the bound dye molecules occurring in NaCl between μ, # 0–25 and μ= 0–5 and in MgCl₂ between μ# 0–01 and μ=0–1.     

Organo group VB chemistry: Part IV: on the NQR spectra of tertiary aryl group VB compounds (35Cl, 75As, 121Sb, 209Bi)

The NQR spectra for the nuclei ³⁵Cl, ⁷⁵As, ¹²¹Sb/¹²³Sb and ²⁰⁹Bi at 300°K in the series of compounds (4-XC₆H₄)₃M and (3-XC₆H₄)₃M (M = P, As, Sb, Bi; X = H, F, Cl) are measured. Hammet sigma constants are calculated. The bonding in these molecules is discussed.     

Chemical separation activities in environmental management at the Idaho National Engineering and Environmental Laboratory

Besides a brief review of the INEEL, examples of chemical separation activities in environmental management are presented in this paper. Under development at the INEEL are separation technologies for the treatment of radioactive wastes, including highly radioactive liquid wastes, solid calcined wastes and mixed wastes, as well as contaminated groundwater and soils. An overview of these technologies, specific applications of the technologies, and the benefits from their use are discussed.     

Reaction of diarylzinc compounds with copper(I) salts. Synthesis and characterization of arylcopper(I) compounds

The reaction of diarylzinc compounds with copper(I) salts is an excellent way of preparing stable arylcopper compounds in quantitative yields. These compounds have been characterized by IR, and by ¹H and ¹³C NMR spectroscopy. Cryoscopic molecular weight determinations show phenylcopper to be polymeric and 2-methylphenylcopper and 2,6-dimethylphenylcopper to be tetrameric in benzene. The compounds are believed to contain aryl groups bridging two copper atoms. Evidence is presented for rotation of these aryl groups around the C(1)—C(4) axis.     

Superacid cyclization of 13E,17E- and 13E,17Z-bicyclogeranylfarnesols and their acetates — An effective structurally selective stereospecific route to scalarane sesterterpenoids

Institute of Chemistry, Moldavian SSR Academy of Sciences, Kishinev. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 759–760, September–October, 1988.     

Level decay and orientational kinetics of the rhodamine B monomer and dimer

The population kinetics and the rotational diffusion of the rhodamine B monomer and dimer were measured by using picosecond pulses from a mode-locked Nd : YAG laser to induce and time resolve the concentration-dependent transient absorption saturation of various aqueous solutions of this organic dye.