Transport processes in the sorption of colored ions by peat particles

A three-step model has been proposed for the adsorption of Astrazone Blue dye (Basic Blue 69) on peat. The initial rate of uptake of dye ions due to physical adsorption and chemisorption (ion exchange) has been correlated using a surface mass transfer coefficient. These coefficients have been determined and expressed in the dimensionless mass transfer form, Sh/Sc^0.33, as a function of agitation, initial dye concentration, peat particle size range, dye solution temperature, and mass of peat.     

Polymer supported chromium porphyrin as catalyst for polycarbonate formation in supercritical carbon dioxide

A new polymer-supported chromium porphyrin has been prepared and fully characterised; its catalytic activity and recyclability were investigated for the ring-opening copolymerisation of 1,2-cyclohexene oxide (CHO) and carbon dioxide (CO2).     

Efficient batch and continuous flow Suzuki cross-coupling reactions under mild conditions, catalysed by polyurea-encapsulated palladium (II) acetate and tetra-n-butylammonium salts

Suzuki cross-coupling reactions are effected in both conventional organic solvents, under continuous flow conditions at 70 degree C, and in batch mode in supercritical carbon dioxide (scCO2), at temperatures as low as 40 degrees C in the presence of palladium(II) acetate microencapsulated in polyurea [PdEnCat] and tetra-n-butylammonium salts.     

Palladium-catalysed cross-coupling reactions in supercritical carbon dioxide

Heck and Suzuki reactions proceed in good yield in supercritical carbon dioxide in the presence of palladium acetate and tri-tert-butylphosphine with both free and polymer-tethered substrates.     

Polyurea-encapsulated palladium(II) acetate: a robust and recyclable catalyst for use in conventional and supercritical media

Palladium(II) acetate microencapsulated in polyurea (MC-[Pd]) is an economical and versatile heterogeneous catalyst for a range of phosphine-free cross-coupling reactions in both conventional solvents and supercritical carbon dioxide (scCO2); the catalyst can be recovered by a simple filtration and recycled up to four times.     

Strengthening Theorems of Dirac and Erdős on Disjoint Cycles

Let be an integer, be the set of vertices of degree at least 2k in a graph G , and be the set of vertices of degree at most in G . In 1963, Dirac and Erd?s proved that G contains k (vertex) disjoint cycles whenever . The main result of this article is that for , every graph G with containing at most t disjoint triangles and with contains k disjoint cycles. This yields that if and , then G contains k disjoint cycles. This generalizes the Corrádi–Hajnal Theorem, which states that every graph G with and contains k disjoint cycles.     

Diaryl ether synthesis in supercritical carbon dioxide in batch and continuous flow modes

A high yielding, batch mode synthesis of diaryl ethers and sulfides by an S(N)Ar fluoride-mediated process in scCO(2) has been developed; the use of a polymer-supported imidazolium fluoride reagent in batch mode led to the development of a fixed-bed continuous flow process, with high conversions.