4-chlorophenol experimental concentrations

Correlation between kinetic rate constant and Hammett s constant of different chlorophenols. Experimental conditions T = 25°C, pH = 7, ozone concentration = 16.8 mg/L. (Data from Abe, K. and Tanaka, K., Chemosphere, 35, 2837-2847, 1997.)... 

Hammett s equation for C02 formation during degradation of chlorophenols. Experimental conditions 20-mL reactor volume initial concentration, 20 mg/L 2.5 g/L TiO initial pH = 4.4-5. 

Figure 2. Part A Degradation of 4-chlorophenol versus time at 3.0 ( ), 1.0 (0), 0.3 (Q), 0.10 (9), and 0.03 (A) mM 4-chlorophenol. Experimental conditions TiO2 = 1 g/L, pH = 4.0, I = 5 X 10r2 M NaN03, oxygen atmosphere, and temperature = 25 °C. Part B The first-order rate constants (Q) and the initial rate constants (%) versus the initial 4-chlorophenol concentration. Part C The reciprocals of the initial rate constant versus reciprocals of the initial 4-chlorophenol concentration.

It is important to note that both H202 and Fe2+ have to be overdosed to maintain a steady-state concentration of hydroxyl radical and to obtain a satisfactory approximation of the mathematical model with the experimental data. When H202 and Fe2+ concentrations are 5 x 10-3 M and 2 x 1th4 M, respectively, the relative rate constants of 2-chlorophenol (2-CP) and 2,4,6-TCP with respect to 2,4-DCP can be calculated. The oxidation and dechlorination constants of 2,4-DCP were found to be 0.995 1/min (fc4) and 0.092 1/min (k2), as reported in a previous study (Tang and Fluang, 1996). For comparison, Table 6.1 summarizes all the kinetic constants as determined in this study and in the related literature. 

Figure 6. Concentration changes of 4-chlorophenol and its intermediates. Experimental conditions 4-chlorophenol = 10 3 M, TiO2 = 1 g/L, pH = 4.0, 1 =...

PTEF for MeB, phenol, 2-chlorophenol and 2,4-dichlorophenol are reported in Figure 7.6. A maximum PTEF can also be evaluated at high enough model pollutant concentrations. PTEF maximum obtained via observed experimental rates PTEFmax ... 

Most studies in TLC have been qualitative, and considerable experimentation may be necessary to obtain quantitative results, although excellent commercial layers and new equipment have aided the problem. Phenolic compounds have been analyzed by spectrophotometry off the plate at 725 nm (133) by means of Folin-Ciocalteu reagent, essentially sodium tungstate and molybdate with lithium sulfate (134). Chlorophenols have been quantified after reaction with dansyl chloride and separation (135). Channel TLC (linear relationships between spot lengths and concentration between 1 and 8 pg/spot) has been used (136). The phenols in cashew nut shell liquid have been quantified by off and on the plate methods with a flying-spot scanning procedure and densitometry (137) and the distribution of unsaturateds by TLC/MS (138). Catecholamines and their metabolites in urine have been quantified (12) and determined by on the plate fluorimetry (139). Hindered phenols have been analyzed by densitometry (140). Semiquantitative determinations of the coupling products of 4,4 -... 

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