Enantiomeric excess determination by fourier transform near-infrared vibrational circular dichroism spectroscopy: simulation of real-time process monitoring.
The first use of near-infrared (NIR) Fourier transform vibrational circular dichroism (FT-VCD) to follow changes in the enantiomeric excess (EE) of chiral sample molecules in time using a flow-cell sampling apparatus is reported. Simultaneous changes in the fractional composition and the EE of a mixture of two different chiral molecules were monitored as a function of time. This simulates the progress of the chemical reaction from a chiral reactant to a chiral product where the mole fractions and EE values of both species may change with time. For the molecules studied, alpha-pinene, camphor, and borneol, the accuracy of following EE changes for one species alone is approximately 2%, while for simultaneously following EE changes in two species it is approximately 3% for 30 min sampling periods at 16 cm(-1) spectral resolution. These findings demonstrate the potential for VCD to be used in the NIR region for real-time monitoring of the composition and %EE of chemical reactions involving the synthesis of chiral molecules.
Guo
Changning
C
Department of Chemistry, Syracuse University, Syracuse, New York 13244, USA.
Shah
Rekha D
RD
Dukor
Rina K
RK
Cao
Xiaolin
X
Freedman
Teresa B
TB
Nafie
Laurence A
LA
D000081008:Bicyclic Monoterpenes; D001892:Camphanes / Q000737:chemistry; D002164:Camphor / Q000737:chemistry; D002942:Circular Dichroism / Q000379:methods*; D039821:Monoterpenes / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*; D013237:Stereoisomerism
D000081008:Bicyclic Monoterpenes; D001892:Camphanes; D039821:Monoterpenes; D002164:Camphor; C005451:alpha-pinene; C022871:isoborneol