A Laboratory Experiment To Measure Henry’s Law Constants of Volatile Organic Compounds with a Bubble Column and a Gas Chromatography Flame Ionization Detector (GC-FID)

Abstract

An undergraduate laboratory experiment is described to measure Henry’s law constants of organic compounds using a bubble column and gas chromatography flame ionization detector (GC-FID). This experiment is designed for upper-division undergraduate laboratory courses and can be implemented in conjunction with physical chemistry, analytical chemistry, environmental chemistry, and toxicology laboratory courses. This experiment can be used to determine solubilities of organic compounds that have important implications in atmospheric chemistry and water pollution and build a useful database through undergraduate experiments.

Effects of temperature, pH, and ionic strength on the Henry's law constant of triethylamine

“…Integrated absorbance peaks (3000.8–2929.5 cm −1 ) as a function of time were used to derive the K H . The mass transfer rate of a solute from liquid phase to gaseous phase can be described by the following equation [ Roberts , ; Ip et al , ; Lee et al , ]: where K H is the Henry's law constant (mol L −1 atm −1 ), C 0 and C t are the concentration of amine vapor at equilibrium and at time t (s) after the equilibrium, respectively, Φ is the gas flow rate (mL min −1 ), R is the gas constant (0.082 atm K −1 M −1 ), T is the temperature (K), V is the water volume (mL), and k is the first‐order hydrolysis loss rate (s −1 ). The whole system was temperature controlled by a refrigerated circulator (VWR 1160S) and worked under atmospheric pressure throughout the experiments.…”

“…Also, as seen in Figure b, the K H values present strong temperature dependence and increase with decreasing temperatures. The K H at 278 K is increased by approximately eightfold as compared to the K H at 298 K. From the temperature‐dependent K H data, we can obtain enthalpy of solution (Δ H sol ) of TEA in water according to the following equation [ Lee et al , ]: where K H ( T ) is Henry's law constant (mol L −1 atm −1 ) measured in this study for a given temperature T (K); K cc ( T ) is a different definition of Henry's law constant, which is defined as K cc ( T ) = C aq / C g ; and Δ H is the molar enthalpy of solution of the solute (kJ mol −1 ). The linear plots of −ln( K cc ) versus 1/ T yield Δ H values of −68.01 ± 2.50 kJ mol −1 (Figure b).…”

“…Integrated absorbance peaks (3000.8-2929.5 cm À1 ) as a function of time were used to derive the K H . The mass transfer rate of a solute from liquid phase to gaseous phase can be described by the following equation [Roberts, 2005;Ip et al, 2009;Lee et al, 2012]:…”

Lowering detection limits for 1,2,3-trichloropropane in water using solid phase extraction coupled to purge and trap sample introduction in an isotope dilution GC-MS method

“…PTI is optimal for analytes with boiling points below 200 C which are also insoluble or poorly soluble in water, e.g., those with moderately high Henry's law constants (Lee et al, 2013;Staudinger and Roberts, 2001). TCP's efficient stripping from water is consistent with its Henry's law constant.…”

A New Experimental Method to Determine the Henry’s Law Constant of a Volatile Organic Compound Adsorbed in Soil

“…Main approaches include static methods like headspace gas chromatography (HSGC) [7,8], the equilibration partitioning in closed systems method (EPICS) [9][10][11] and further development by combination with solid-phase microextraction [12]. Simultaneously, dynamic equilibration methods have been widely used based on bubble columns [13][14][15][16] and generalized later by the inert gas stripping method [17,18] One of the recent methods proposed by Richon [19] achieves a considerable improvement of HLC measurement in terms of speed, accuracy, and simplicity. Anyway, all these different methods rely on expensive measuring devices including gas chromatography [1,10,11,15,17,18,[20][21][22][23], liquid chromatography [14], or infrared spectrometer [16].…”