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Determination of Metals in Non Saline Sediments
Published in T. R. Crompton, Determination of Metals and Anions in Soils, Sediments and Sludges, 2020
Quin and Brookes [61] determined tungsten in sediments by fusing the sample with potassium hydrogen sulphate and leaching the melt in 10M hydrochloric acid. A clear portion of the acid extract is heated with a solution of stannous chloride in 10M hydrochloric acid. A solution of dithiol in isoamyl acetate is added and the mixture is heated under precisely defined conditions so that a globule containing the tungsten dithiol complex is formed in >6 h. The globule is dissolved in light petroleum (boiling range 80° to 100°) and the extinction of the solution is measured at 630nm. Down to 1 ppm of tungsten can be determined and Beer’s law is obeyed for up to 300 ppm. Modifications to conditions can improve the sensitivity to 0.2 ppm. Low concentrations of molybdenum do not interfere.
N-Polyheterocycles
Published in Navjeet Kaur, Metals and Non-Metals, 2020
Quinoxalines are generally less investigated compounds. However, growing efforts are being made to characterize and synthesize these compounds of late. 4-Amino-3-nitrophenol is reduced with stannous chloride in hydrochloric acid to provide 3,4-diaminophenol. The substrate 3-methylquinoxaline-2(1H)-one is prepared when o-phenylenediamine reacts with pyruvic acid under microwave heating in the presence of 6N hydrochloric acid. 4-{[-3-Methyl-2-oxoquinoxaline–1(2H)methyl]amino}benzoic acid is synthesized by Mannich reaction of 3-methylquinoxaline-2(1H)-one, formaldehyde and 4-aminobenzoic acid. Consequently, 1-({[4-(1H-benzimidazol-2-yl)phenyl]amino}-methyl)-3-methylquinoxaline-2(1H)-one is formed when 4-{[-3-methyl-2-oxoquinoxaline-1(2H)methyl]amino}benzoic acid reacts with o-phenylenediamine (Scheme 61) [128].
Catalytic Reforming Catalysts
Published in Soni O. Oyekan, Catalytic Naphtha Reforming Process, 2018
After the formation of the shaped alumina pellets or “extrudates,” platinum, promoter metals, and chloride impregnations are conducted so as to deposit the necessary calculated concentrations of platinum, promoter metals, and chloride on the alumina. Precursor metal compounds such as chloroplatinic acid, perrhenic acid, ammonium perrhenate, hydrochloric acid, and stannous chloride are used. Depending on the catalyst to be manufactured, the appropriate set of precursor metal compounds, hydrochloric acid, and impregnating agents are used. Hydrochloric acid and carbon dioxide have been used as impregnating agents to facilitate uniform distributions of platinum, promoter metals, and chloride. After the metal and chloride impregnation step, drying and calcination procedures are conducted at moderate temperatures to complete the catalyst production.
Desulfurization and de-ashing of low-rank coal by catalytic oxidation using Sn as catalyst loaded in different forms
Published in International Journal of Coal Preparation and Utilization, 2022
Waqas Ahmad, Ishraq Ahmad, Imtiaz Ahmad, Muhammad Yaseen, Nisar Muhammad, Muhammad Salman
The coal sample was collected from the coal mines located in Darra Adam Khel, Khyber Pakhtunkhwa. All the chemicals used in this work were of analytical grade. H2O2 (35%) and Formic Acid (99%) were provided by sigma Aldrich. Tin chloride or stannous chloride (SnCl2), a dehydrated white crystalline, odorless solid having molecular mass of 189.6 g/mol, density of 3.95 g/cm3, melting point of 247 °C and boiling point of 623 °C, was used as a catalyst precursor provided by Sigma Aldrich. Nitric acid (63%) and Ammonia solution (35%), Eschka Mixture, Barium chloride (BaCl2) and Potassium hydroxide (KOH) were supplied by BDH laboratories supplier. Activated Carbon (AC) used as support was purchased from Merck (Germany). Double-distilled water was used throughout the experiments.