TY - JOUR
T1 - Formation of carbamic acid in organic solvents and in supercritical carbon dioxide
AU - Dijkstra, Z.J.
AU - Doornbos, A.R.
AU - Weyten, H.
AU - Ernsting, J.M.
AU - Elsevier, C.J.
AU - Keurentjes, J.T.F.
PY - 2007
Y1 - 2007
N2 - The behavior of amines in various CO2-rich solvents is described. 1H and 13C NMR spectra in DMSO, chloroform, and benzene show that the amines are completely converted into carbamic acid by just bubbling atm. CO2 through the soln. However, the chem. shifts of several protons and the carbonyl 13C in the newly formed compds. strongly depend on the org. solvent used. FT-IR measurements confirm the observation that carbamic acid formation occurs. Changing the solvent to supercrit. CO2 shows a temp.- and pressure-dependent equil. between the amine and the carbamic acid; higher pressures shift the equil. towards the carbamic acid, whereas higher temps. favor the free amine.
AB - The behavior of amines in various CO2-rich solvents is described. 1H and 13C NMR spectra in DMSO, chloroform, and benzene show that the amines are completely converted into carbamic acid by just bubbling atm. CO2 through the soln. However, the chem. shifts of several protons and the carbonyl 13C in the newly formed compds. strongly depend on the org. solvent used. FT-IR measurements confirm the observation that carbamic acid formation occurs. Changing the solvent to supercrit. CO2 shows a temp.- and pressure-dependent equil. between the amine and the carbamic acid; higher pressures shift the equil. towards the carbamic acid, whereas higher temps. favor the free amine.
U2 - 10.1016/j.supflu.2006.08.012
DO - 10.1016/j.supflu.2006.08.012
M3 - Article
VL - 41
SP - 109
EP - 114
JO - Journal of Supercritical Fluids
JF - Journal of Supercritical Fluids
SN - 0896-8446
IS - 1
ER -