3252-43-5Relevant articles and documents
Paired Electrosynthesis of Cyanoacetic Acid
Batanero, Belen,Barba, Fructuoso,Sanchez-Sanchez, Carlos M.,Aldaz, Antonio
, p. 2423 - 2426 (2004)
Cyanoacetic acid is formed by cathodic reduction of CO2 and anodic oxidation of the tetraalkylammonium salt anion; the process is conduced in acetonitrile using a divided cell with a medium porosity glass-frit diaphragm. A mechanism for this paired electrochemical reaction is proposed.
The photochemical and thermal decomposition of azidoacetylene in the gas phase, solid matrix, and solutions
Zeng, Xiaoqing,Beckers, Helmut,Seifert, Jennifer,Banert, Klaus
, p. 4077 - 4082 (2014/07/08)
Decomposition of the extremely explosive and unstable parent compound of 1-azidoalkynes, HCCN3 (azidoacetylene), was studied in the gas phase, solid argon matrix, and solutions. In the gas phase, this azide decomposes quickly at room temperature with a half-life time (t1/2) of 20 min at an initial pressure (p0) of 0.8 mbar. The decay (p0 = 1.0 mbar) is significantly increased in an atmosphere of O2 with t 1/2 of 3 min, in which HC(O)CN was identified as the trapping product of the cyanocarbene intermediate HCCN. Trapping products of this carbene by solvent molecules (CH2Cl2 and CHCl3) were also found during decomposition of the azide in solution, whereas the reaction with a solution of bromine to form dibromoacetonitrile is interpreted as taking place by nucleophilic attack of the alkyne itself. The intermediary formation of triplet HCCN by flash vacuum pyrolysis and photolysis (255 nm) of the azide in the gas phase and in solid argon matrices, respectively, was confirmed by IR spectroscopy and mutual photo-interconversion of HCCN with isomeric cyclo-C(H)CN (azirinylidene) and HCNC by selective irradiations at 16 K. Although azidoacetylene is highly explosive, it can be irradiated in an argon matrix to generate cyanocarbene. The same species is also formed and analyzed after flash vacuum pyrolysis under relatively mild conditions. Decomposition of the azide in solution is combined with trapping reactions. Copyright
Chemistry of the biosynthesis of halogenated methanes: C1-organohalogens as pre-industrial chemical stressors in the environment?
Urhahn, Thorsten,Ballschmiter, Karlheinz
, p. 1017 - 1032 (2007/10/03)
We have chemical evidence that in the biosynthesis of the halomethanes C1H(4-n),X(n) (n = 1-4) three different pathways of biogenic formation have to be distinguished. The formation of methyl chloride, methyl bromide, and methyl iodide, respectively, has to be considered as a methylation of the respective halide ions. The dihalo- and trihalomethanes are formed via the haloform and/or via the sulfo-haloform reaction. The possible formation of tetrahalomethanes may involve a radical mechanism. Methionine methyl sulfonium chloride used as substrate in the incubation together with chloroperoxidase (CPO) and H2O2 gave high yields of monohalomethanes only. We were able to show that next to the CPO/H2O2 driven haloform reaction of carbonyl activated methyl groups also methyl-sulphur compounds - e.g. dimethylsulfoxide, dimethylsulfone, and the sulphur amino acid methionine - can act as precursors for the biosynthesis of di- and trihalogenated methanes. Moreover, there is some but not yet very conclusive evidence for an enzymatic production of tetrahalogenated methanes. In our experiments with chloroperoxidase involving amino acids and complex natural peptide based substrates, dihalogenated acetonitriles and several other volatile halogenated but yet unidentified compounds were formed. On the basis of these experiments we like to suggest that biosynthesis of halogenated nitriles occurs in general and therefore a natural atmospheric background should exist for halogenated acetonitriles and halogenated acetaldehydes, respectively.
