A. Jarczewski, I. Binkowska
2001
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0
Influential Citations
4
Citations
Journal
Polish Journal of Chemistry
Abstract
4-Nitrophenyl[bis(ethylsulphonyl)]methane has been synthesized and used in kinetic studies of proton abstraction induced by 1,1,3,3-tetramethylguanidine (TMG), 1,5,7-triazabicyclo[4.4.0]dec-5-ene(TBD)and 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-enc (MTBD) bases in acetonitrile. The pK a values of this carbon acid in water and in acetonitrile solvents are 10.08 and 22.8 respectively. The electronic spectra of4-nitro-phenyl[bis(ethylsulphonyl)]methane and its anion are well defined and temperature dependent. The rates of proton abstraction are large as the reaction occurs in the range of microseconds. The relaxation times were studied by spectrophotometric temperature-jump technique. The rate constants for proton transfer reaction promoted by TMG, TBD and MTBD bases in acetonitrile are: 1.39x10 5 -2.11x10 5 ; 8.8x10 6 -19.2×10 6 , 0.84X10 5 -2.43X10 5 [dm 3 mol - 1 s - 1 ]respectively between 20-40°C. The enthalpies of activation are: