For comparison, free 4-isopropylpyridine gives signals at δ=8.50 (d), 6.68 (d), 2.42 (sept), and 0.90 ppm (d) by using the same NMR conditions.
For comparison, free 4-ethylpyridine gives signals at δ=8.47 (d), 6.71 (d), 2.20 (q), and 0.90 ppm (t) by using the same NMR conditions.
The Pb2+ ion solutions with different initial concentrations (400, 500, 600, 700 ppm) were prepared by using the 1000 ppm standard stock solution.
C NMR spectra are reported in ppm from tetramethylsilane by using the central peak of the solvent as reference (CD2Cl2: δ=54.0 ppm, [D1]TFA: δ=116.6 ppm), multiplicity with respect to proton (deduced from APT experiments, s=quaternary C, d=CH, t=CH2, q=CH3).
The NMR spectra over the range of δ 0.5 10.0 ppm were reduced by using AMIX (Bruker Analytik, Rheinstetten, Germany) to regions, each 0.01 ppm wide, and the signal intensity in each region was integrated.
Before spectral analysis, all acquired free induction decays (FIDs) were zero-filled to 32 K data points, multiplied with a 0.3 Hz line-broadening function, Fourier transformed, manually phased, and the TSP internal reference peak was set to 0 ppm by use of ACD/SpecManager software version 12.0 [ 13].
NMR spectra were processed and binned for the region of d 0 10 ppm (water peak region d 4.7-4.83 ppm excluded) within 0.04 ppm chemical shift window by using the NMR software package NMR Suite 5.0 (Chenomx, Edmonton, Canada).
At 5 days after treatment with O2, fungal inhibition expressed by SCI was 10% for a level of 2000 ppm while this value became 26.67% for a level of 1000 ppm and 36.67% by using of this essential oil to a level of 500 ppm.
A product gas with above 85% hydrogen purity and traces of CO2 (less than 300 ppm) and CO (less than 30 ppm) was continuously produced by using a 6 m long adsorptive reactor with three-subsections and can be directly used in fuel cell applications.
