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BACKGROUND The determination of impurity elements in hydrometallurgical zinc sulfate solution is helpful to optimize the composition of electrolytes, reduce energy consumption, and accurately feed and improve the purity of smelting metal. Impurity elements in the wet zinc smelting process are usually determined by manual sampling. The sample needs to be diluted before the equipment analysis is performed due to high content of zinc and sulfuric acid, which is difficult to achieve automatic analysis. OBJECTIVES In order to determine the online analysis of impurity elements in the solution of zinc smelting process and meet the current requirements of the hydrometallurgical industry. METHODS An automatic industrial on-line filtration/dilution combined with inductively coupled plasma-optical emission spectrometry (ICP-OES) was used. By optimizing key parameters and selecting appropriate analysis lines, a method for the rapid determination of copper, cadmium, cobalt and iron in zinc smelting solution was developed. RESULTS The experimental results showed that the linear relationship of each element was good, the correlation coefficient was greater than 0.9998, the relative standard deviation was 0.72%-1.39% (n=6), and the spiked recovery was 95%-110%. CONCLUSIONS The factory on-line automatic analysis system can replace traditional manual sampling to achieve automatic analysis. The results of on-line analysis are compared with those of manual sampling in actual production, showing good consistency. This method can be used to fully achieve automatic analysis, simple operation, accurate and reliable results, and is suitable for the analysis of impurity elements in zinc smelting.

Described herein is the development of a desaturation and N‐β‐nitration reaction of cyclic amides, which is achieved by a selective hydrogen atom transfer (HAT)/oxidative desaturation/electrophilic nitration process. In this procedure, di‐tert‐butyl peroxide (DTBP) acted both as the oxidant and HAT reagent, and electrophilic NOBF4 as nitration source. Notably, the application of produced cyclic nitroene‐sulfonamides was showcased by their efficient transformations into 3‐piperidones and poly‐substituted piperidine derivatives. [ABSTRACT FROM AUTHOR]

Covalent attachment of a 1,2,4‐triazole iridium complex to mesoporous MCM‐41 generated a heterogeneous catalyst that was found to be effective in the synthesis of 2‐aryl isoindolines, quinolines, cyclic amines, and symmetrical secondary amines through a cascade borrowing hydrogen strategy. Interestingly, the supported heterogeneous iridium catalyst prepared from the 1,2,4‐triazole iridium complex and mesoporous MCM‐41 exhibited high catalytic activity in the preparation of 2‐aryl isoindoline derivatives and symmetrical secondary amines. The catalyst system is highly recyclable for at least five times. Besides the important effect of the triazole, iridium sites grafted on siliceous supports can act as multifunctional catalytic centers and thus greatly enhance the catalytic activity of the catalysts. Furthermore, mechanistic experiments revealed that the reaction is initiated by an initial alcohol dehydrogenation and promoted by an iridium hydride intermediate. Importantly, the direct detection of a diagnostic iridium hydride signal confirmed that the synthesis of 2‐aryl isoindolines occurs by a borrowing hydrogen process. This work provides an efficient example of isoindolines synthesis through a borrowing hydrogen strategy. [ABSTRACT FROM AUTHOR]