Hydrogen concentration from infrared absorption

Infrared. The measurements were carried out with a Unicam SP100 spectrophotometer using a 10-cm. gas cell. The concentration of acetylene was estimated by measuring the optical density of the absorption band at 729 cm. 1 and that of hydrogen cyanide from the optical density of the absorption band at 712 cm. 1... 

The exit gas from the generator ice trap is dissolved directly in water. The hydrogen-ion concentration of the resulting solution is determined by titration with standard base, and the iodide-ion concentration by the precipitation of silver iodide. Only traces of tetrahydronaphthalene are detected by the very slight carbon-hydrogen bond-infrared absorption in the samples of the anhydrous gas prepared by this procedure. 

Fig. 4. Variation in the concentrations of the broad (clustered phase) (solid curve with crosses) and narrow (less clustered or distributed phase) (dashed curve with triangles) NMR components as functions of hydrogen concentration for samples that exhibit only monohydride bonding in infrared absorption measurements. [From Jeffrey and Lowry (1981).]...

The role of specific interactions in the plasticization of PVC has been proposed from work on specific interactions of esters in solvents (eg, hydrogenated chlorocarbons) (13), work on blends of polyesters with PVC (14—19), and work on plasticized PVC itself (20—23). Modes of iateraction between the carbonyl functionaHty of the plasticizer ester or polyester were proposed, mostly on the basis of results from Fourier transform infrared spectroscopy (ftir). Shifts in the absorption frequency of the carbonyl group of the plasticizer ester to lower wave number, indicative of a reduction in polarity (ie, some iateraction between this functionaHty and the polymer) have been reported (20—22). Work performed with dibutyl phthalate (22) suggests an optimum concentration at which such iateractions are maximized. Spectral shifts are in the range 3—8 cm . Similar shifts have also been reported in blends of PVC with polyesters (14—20), again showing a concentration dependence of the shift to lower wave number of the ester carbonyl absorption frequency. 

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