Electrochemical corrosion monitoring in low conductive fluid : pilot-scale study on sulfolane corrosion potential

Solvents are a group of chemical compounds that are widely used in organic synthesis. Taking into account the chemical nature, solvents are divided into protic and aprotic ones. An attractive alternative to commonly used industrial extractive liquids is an anthropogenic, organosulfur medium—sulfolane. Sulfolane is a five-membered heterocyclic sulfur–organic compound from the group of sulfones (R-SO2-R’, where R/R’ is alkyl, alkenyl, or aryl), which contains an apolar hydrocarbon backbone and a polar functional group. It is a selective solvent in the liquid–liquid and liquid–vapor extraction processes used for the removal of close-boiling alkanes from cycloalkanes or for the separation of compounds with different degrees of saturation and polarity in the extractive rectification of arenes from non-aromatic saturated hydrocarbon mixtures. In standard conditions sulfolane is not an aggressive solvent for steel, but at higher temperature (170–180 °C) and oxygen availability, it may be decomposed and subsequently some corrosive (by-)products can be formed. The primary purpose of the presented pilot-case examination was to verify applicability of the industrial, multi-electrochemical technique for reliable detection of the corrosion processes in low conductive fluids

Rapid and simple TLC-densitometric method for assay of clobetasol propionate in topical solution

A rapid, simple to use and low-cost thin-layer chromatographic procedure in normal phase system with densitometric detection at 246 nm was carefully validated according to the International Conference on Harmonisation (ICH) guidelines for assay of clobetasol propionate in topical solution containing clobetasol propionate in quantity 0.50 mg/mL. The adopted thin-layer chromatographic (TLC)-densitometric procedure could effectively separate clobetasol propionate from its related compound, namely clobetasol. It is linear for clobetasol propionate in the range of 0.188 5 g/spot. The limit of detection (LOD) and limit of quantification (LOQ) value is 0.061 and 0.186 g/spot, respectively. Accuracy of proposed procedure was evaluated by recovery test. The mean recovery of studied clobetasol propionate ranges from 98.7 to 101.0%. The coefficient of variation (CV, %) obtained during intra-day and inter-day studies, which was less than 2% (0.40 1.17%), confirms the precision of described method. The assay value of clobetasol propionate is consistent with the pharmacopoeial requirements. In conclusion, it can be suitable as a simple and economic procedure for routine quality control laboratories of clobetasol propionate in topical solution

Potassium ferrate (VI) as the multifunctional agent in the treatment of landfill leachate

Possible use of potassium ferrate (VI) (K2FeO4) for the treatment of landfill leachate (pH = 8.9, Chemical Oxygen Demand (COD) 770 mg O2/L, Total Organic Carbon (TOC) 230 mg/L, Total Nitrogen (Total N) 120 mg/L, Total Phosphorus (Total P) 12 mg/L, Total Coli Count (TCC) 6.8 log CFU/mL (Colony-Forming Unit/mL), Most Probable Number (MPN) of fecal enterococci 4.0 log/100 mL, Total Proteolytic Count (TPC) 4.4 log CFU/mL) to remove COD was investigated. Central Composite Design (CCD) and Response Surface Methodology (RSM) were applied for modelling and optimizing the purification process. Conformity of experimental and predicted data (R2 = 0.8477, Radj 2 = 0.7462) were verified using Analysis of Variance (ANOVA). Application of K2FeO4 using CCD/RSM allowed to decrease COD, TOC, Total N, Total P, TCC, MPN of fecal enterococci and TPC by 76.2%, 82.6%, 68.3%, 91.6%, 99.0%, 95.8% and 99.3%, respectively, by using K2FeO4 0.390 g/L, at pH = 2.3 within 25 min. Application of equivalent amount of iron (as FeSO4 7H2O and FeCl3 6H2O) under the same conditions allowed to diminish COD, TOC, Total N, Total P, TCC, MPN of fecal enterococci and TPC only by 38.1%, 37.0%, 20.8%, 95.8%, 94.4%, 58.2%, 90.8% and 41.6%, 45.7%, 29.2%, 95.8%, 92.1%, 58.2%, 90.0%, respectively. Thus, K2FeO4 could be applied as an environmentally friendly reagent for landfill leachate treatment