18197-25-6Relevant articles and documents
Ray et al.
, p. 1052 (1956)
Ozone and ozone/vacuum-UV degradation of diethyl dithiocarbamate collector: Kinetics, mineralization, byproducts and pathways
Fu, Pingfeng,Ma, Yanhong,Yang, Huifen,Li, Gen,Lin, Xiaofeng
, p. 23579 - 23588 (2019/08/12)
The diethyl dithiocarbamate (DDC) collector, a precursor of toxic N-nitrosamines, is detected in flotation wastewaters usually at the ppm level. In this study, the O3 and O3/Vacuum-UV (O3/VUV) processes were compared to investigate the efficient removal of DDC with a low risk of N-nitrosamine formation. The results showed that 99.55% of DDC was removed at 20 min by O3/VUV, and the degradation rate constant was 3.99 times higher than that using O3-alone. The C, S and N mineralization extents of DDC using O3/VUV reached 36.36%, 62.69% and 79.76% at 90 min, respectively. O3/VUV achieved a much higher mineralization extent of DDC than O3-alone. After 90 min of degradation, O3/VUV achieved lower residual concentrations of CS2 and H2S, and released lower amounts of gaseous sulfur byproducts compared to O3-alone. The solid phase extraction and gas chromatography-mass spectrometry (SPE/GC-MS) analysis indicated that the main byproducts in O3/VUV degradation of DDC were amide compounds without the detection of N-nitrosamines. The avoidance of N-nitrosamine formation might be attributed to exposure of UV irradiation and enhanced formation of OH radicals in the O3/VUV system. The degradation pathways of DDC were proposed. This work indicated that O3/VUV was an efficient alternative treatment technique for the removal of DDC flotation collector with low risk of N-nitrosamine formation.
Solvent-induced reduction of palladium-aryls, a potential interference in pd catalysis
Molina De La Torre, Jesus A.,Espinet, Pablo,Albeniz, Ana C.
, p. 5428 - 5434 (2013/11/06)
The decomposition of the Pd-aryl complex (NBu4) 2[Pd2(μ-Br)2Br2(C 6F5)2] (1) to the reduction product C 6F5H was checked in different solvents and conditions. 1 is not stable in N-alkyl amides (DMF, NMP, DMA), cyclohexanone, and diethers (1,4-dioxane, DME) at high temperatures (above 80 C). Other solvents such as nitriles, THF, water, or toluene are safe, and no significant decomposition occurs. The solvent is the source of hydrogen, and the decomposition mechanisms have been identified by analyzing the reaction products coming from the solvent. β-H elimination involving the methyl group in a N-coordinated amide is the predominant pathway for amides. An O-coordinated diether undergoes β-H elimination and subsequent deprotonation of the resulting oxonium salt to give an enol ether. A palladium enolate from cyclohexanone leads to cyclohexenone, a reaction favored by the presence of a base. Oxygen strongly increases the extent of decomposition, and we propose this occurs by reoxidation of the Pd(0) species formed in the process and regeneration of active Pd(II) complexes.
Reaction of iodo(trimethyl)silane with N,N-dimethyl carboxylic acid amides
Voronkov,Tsyrendorzhieva,Lis,Rakhlin
experimental part, p. 791 - 793 (2010/10/04)
The reactions of iodo(trimethyl)silane with N,N-dimethylformamide and N,N-dimethylacetamide Me2NCOR (R = H, Me) at a molar ratio of 1: 2 involved mainly cleavage of the N-C(=O) bond with formation of up to 80% of N,N-dimethyltrimethylsilylamine Me3SiNMe2 and the corresponding acyl iodide RCOI. In the reaction with N,N-dimethylformamide, formyl iodide HCOI was detected for the first time by gas chromatography-mass spectrometry. The contribution of Me-N bond cleavage, leading to N-methyl-N-trimethylsilyl derivative Me(Me3Si)NCOR and methyl iodide was considerably smaller. Another by-product was the corresponding N-methyl imide MeN(COR)2 formed by reaction of the initial amide with acyl iodide. The primary intermediate in the reaction of iodo(trimethyl)silane with DMF and DMA is quaternary ammonium salt [Me2(Me3Si)N +COR] I- which decomposes via dissociation of the N-CO and N-Me bonds.
