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In this study, α-, β-, and δ-MnO2 were prepared by a uniform hydrothermal method and then coupled with vacuum ultraviolet (VUV) for the degradation of gaseous unsymmetrical dimethylhydrazine (UDMH). The performance in the removal of UDMH, by-product distribution and mechanism were systematically investigated. The catalysts were characterized by X-ray diffraction (XRD), N2 adsorption/desorption, Field Emission Scanning Electron Microscopy (FE-SEM), Raman, thermogravimetry (TG), Fourier-transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR) to investigate the factors affecting the catalytic activity. The results showed that O2 and H2O were essential for the removal of UDMH. Photooxidation and ozone catalytic oxidation contribute to the removal and mineralization of UDMH. The integrated process considerably improved the removal and mineralization of UDMH by ozone catalytic oxidation. More reactive oxygen species were generated in the integrated process. The catalytic activity of the prepared catalysts follows the order: δ-MnO2 > α-MnO2 > β-MnO2. δ-MnO2 displayed the highest removal rate of 100% and a CO2 concentration of 42 ppmv. The good performance of δ-MnO2 was mainly attributed to the large number of surface oxygen vacancies.

Unsymmetrical dimethylhydrazine (UDMH) contaminated waste gas and related intermediates pose a great threat to human health. TiO2-reduced graphene oxide aerogel (rGA) samples with different graphene content levels were synthetized and characterized for the degradation of UDMH. The effects of GO content, humidity, and temperature were investigated under UV and VUV light, with highest UDMH conversion values of 68% and 95%, respectively. Compared with pure TiO2, the enhanced degradation activity of TiO2-rGA under UV light can be attributed to a synergetic effect between absorption and photocatalysis, while the high UDMH conversion under VUV light relies on photolysis and ozonation. The high oxygen-containing group content, rather than a high SSA, and electron trapping by graphene are key factors determining the outstanding performance of TiO2-rGA with 80 mg of GO. The prepared TiO2-graphene aerogels are promising for the degradation of gas-phase UDMH. This journal is

Simple and efficient methods have been developed to obtain cyanomethylamines and azidomethylamines using reactions of methoxymethylamines with TMSCN and TMSN3, respectively. In the case of dimethylformamide dimethylacetal, only one MeO group wa

The present invention relates to heterocyclic compounds which have been found to have anti-tumour activity. More specifically, the invention concerns Pyrrolo ?3,2-b! carbazoles, 1H-Benzofuro ?3,2-f! indoles and 1H-?1! Benzothieno ?2,3-f! indoles, methods for their preparation, pharmaceutical formulations containing them and their use as anti-tumour agents.

The thermolysis reactions of 3a and 2a, b were studied over a temperature range of 40°C and the activation parameters were determined. They were compared with the activation parameters of structurally comparable hydrocarbons of similar strain in order to obtain the radical stabilization enthalpies RSEs of the cyano(dimethylamino)methyl radical 1a. For this comparison the geminal interaction enthalpies of the cyano and the dimethylamino groups in the ground state had to be determined for the series of amino nitrites 4a-4c and 4j-4n by thermochemical methods. The geminal interaction in the ground state varies between -0.6 kcal/mol stabilization in 4a and a destabilization of +10.7 and +7.0 kJ mol-1 for secondary and tertiary α-dialkylaminonitriles, respectively. A synergistic (i.e. more than additive) stabilization enthalpy of 26 kJ mol-1 of la was found in contrast to predictions in the literature. This stabilization is interpreted by conjugation between the substituents, which are separated by the radical center. (Chemical Equation Presented) VCH Verlagsgesellschaft mbH, 1997.

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An unprecedented transformation of N,N-dimethylamides into dimethylaminoacetonitrile (1) by passing through a 13.56 MHz gaseous discharge was found.Diethylaminoacetonitrile (2) was similarly given from N,N-dimethylformamide.

The rate constants for formation and decay of O-acylureas from carbodi-imide and acids have been measured using aqueous media.The O-acetylisourea from acetate and N-ethyl-N'-(3-trimethylammoniopropyl)carbodi-imide (ETC) possesses an acidic group of pK 6.8 and decomposes (k2) in its acid form as the dication by reaction with acetate ion or water.The reaction of the carboxylate anion with ETC is general acid catalysed (k1 = ΣkHA-> and the deuterium oxide solvent isotope effect indicates a rate-limiting proton transfer except for the oxonium ion acting as acid.The Broensted α value for variation of the structure of HA (0.67) is consistent with a proton transfer concerted with nucleophilic attack by the acetate anion.A concerted mechanism is consistent with the weak basicity of the carbodi-imide and the weak acidity of the isourea adduct.The third-order term involving acetic acid, acetate ion, and carbodi-imide carries ca. 60 percent of the total reaction flux at pH 6.80 and 1 M total acetic acid buffer concentration.At this pH ca. 40 percent of the reaction flux goes through the stepwise 'Khorana' mechanism with specific acid catalysis.Intramolecular general acid catalysis is demonstrated to occur in the reaction of 2,2-diethylmalonic acid monoanion with ETC and the effective molarity compared with intermolecular catalysis is 15 M.Attack of carboxylate anions on ETC with N-chloroethylmorpholinium ion as the general acid has a Broensted type βN of 0.46.

Activation energies for a number of hydrogen abstraction reactions of interest in mechanistic organic electrochemistry have been calculated using the bond energy-bond-order (BEBO) and equibonding method.The main emphasis has been put on processes with bearing on the problem of deciding between direct and indirect mechanisms in anodic oxidation, viz. acyloxylation, hydroxylation, methoxylation, nitrooxylation, cyanation, carbomethoxylation and azidation.The results indicate that indirect mechanisms might play a more important role than presently assumed.

Process for the preparation of unsaturated aldehydes, in particular γ,δ-unsaturated aldehydes, which comprises reacting an amino-nitrile with a basic or a neutral agent. The products obtained in accordance with the process of the invention are useful intermediates for the preparation of flavoring ingredients.