Studies on complexation and solvent extraction of lanthanides in the presence of diaza-18-crown-6-di-isopropionic acid.
Stability constants of some lanthanides with K22DAP (diaza-18-crown-6-diisopropionic acid) were determined by potentiometric titration method. The logarithmic values of these constants for La(III), Nd(III), Sm(III), Gd(III), Tb(III), Dy(III), Er(III), and Lu(III) are 11.14, 11.43, 11.78, 11.74, 11.95, 12.09, 11.49, and 10.88, respectively. Solvent extraction studies were carried out on the K22DAP complexes of La(III), Nd(III) and Lu(III) using TTA (thenoyltrifluoroacetone) as an extractant in different diluents. It appears that nitrobenzene, a diluent with high dielectric constant, favors the extraction of the complexes. Extraction rates of the K22DAP complexes of lanthanides were investigated at pH 5.5 and 8.0 with TTA in chloroform. The rates of extraction are found to be dependent upon the nature of the extracted species. Competitive extractions were carried out to see if selective extractions could be achieved.
Recovery of lanthanum(III) from aqueous solution using biosorbents of plant and animal origin: Batch and column studies
Abstract The present investigation attempts to recover lanthanum(III) from aqueous environments using biosorbents of animal (fish scales) and plant origin (neem saw dust). Optimization experiments were carried out using a log transformed 5-level Box–Behnken design. Maximum La(III) uptake was noted to be 200.0 mg/g in the case of fish scales (FS) and 160.2 mg/g in the case of neem sawdust (NS) under optimum conditions (pH: 6.0, biomass dosage: 0.3 g/L; 0.2 g/L, initial metal concentration: 300 mg/L; 250 mg/L, temperature: 50 °C, time: 4 h; 3 h). A low p -value of
One-pot synthesis of annulated pyrido[2,3-d:6,5-d]dipyrimidine derivatives using nitrogen based DBU catalyst in aqueous ethanol medium
Abstract We have reported DBU as an efficient organocatalyst for one-pot three-component synthesis of annulated pyrido[2,3- d :6,5- d ]dipyrimidine derivatives using aromatic aldehyde, thio-barbituric acid and 6-amino-uracil in aqueous ethanol under reflux. The attractive advantages of this process are mild reaction conditions, environment friendly procedure, short reaction times, easy isolation of products, and excellent yields (72–89%).