Reactive extraction of cis,cis-muconic acid from aqueous solution using phosphorus-bonded extractants, tri-n-octylphosphineoxide and tri-n-butyl phosphate: Equilibrium and thermodynamic study

Ru(III) -based polyoxometalate tetramers as highly efficient heterogeneous catalysts for alcohol oxidation reactions at room temperature

A novel ruthenium-containing polyoxometalate-based organic-inorganic hybrid, K₄Na₉H_7.4[(AsW₉O₃₃)₄(WO₂)₄{Ru_3.2(C₃H₃N₂)₂}]·42H₂O (1), was successfully synthesized by a one-step hydrothermal method under acidic conditions, which applied a self-assembly strategy between inorganic polyoxometalate based on trivacant [B-α-AsW₉O₃₃]^9- {AsW₉} fragments and an organic ligand, imidazole (C₃H₄N₂). Compound 1 was further characterized by single-crystal X-ray diffraction, PXRD, IR spectroscopy, UV-Vis spectroscopy, ESI-MS, elemental analysis and TGA. Single-crystal X-ray diffraction data reveal that the polyanion consists of four trivacant Keggin-type polyanion {AsW₉} building blocks bridged by four {WO₆} units, leading to a crown-shaped tetrameric structure [(AsW₉O₃₃)₄(WO₂)₄{Ru_3.2(C₃H₃N₂)₂}]^20.4-. The ESI-MS result reveals that the polyanion unit has excellent structural integrity in water. Moreover, the catalysis study of 1 was also further investigated, and the experimental results indicate heterogeneous catalyst 1 presents high efficiency (yield = 98%), excellent selectivity (>99%), and good recyclability for the oxidation of 1-(4-chlorophenyl)ethanol to 4'-chloroacetophenone with commercially available 70% aqueous tert-butyl hydroperoxide {TBHP (aq.)} as the oxidant at room temperature.

Equilibrium & kinetic studies of reactive extraction of trans-aconitic acid using sunflower oil with tri-n-octylamine

In order to design an efficient extraction system for the separation of biochemically produced trans-aconitic acid (TAH) from fermentation broth; equilibrium and kinetics of reactive extraction of TAH from aqueous solutions was investigated using tri-n-octylamine (TOA) as an extractant and sunflower oil as a diluent. Through the equilibrium studies stoichiometry (acid, extractant) of complex formations was determined with the help of loading ratio. Formation of (1, 1), (2, 1), & (3, 1) stoichiometry complexes were observed having complexation constants values 179.73 kmol−1 m3, 9512.58 kmol−2 m6, and 614,407.02 kmol−3 m9, respectively. Kinetics experiments were performed in Lewis type stirred cell and results confirmed that reaction between TAH and TOA in sunflower oil fall in regime 1, i.e. slow reaction occurring in bulk organic phase. The overall order of reaction is pseudo first order with rate constant (K mn ) 1.78 × 10−5 (kmol m−3)−0.71 s−1 and physical mass transfer coefficient (K l ) 4.22 × 10−5 m s−1.