As important controlling factors for the synthesis of iron phosphate materials by liquid-phase precipitation, the solubilities of iron phosphate dihydrate were systematically measured at H_3PO_4 concentrations from 1.13 wt%to 10.7 wt%, temperature from 298.15 to 363.15 K, and atmosphere pressure in this work. The solubility was found to increase 5 orders of magnitude or more with increasing the concentration of phosphoric acid, and decrease 1 to 2 orders of magnitude with increasing the equilibrium temperature. The phosphoric acid addition and temperature were found to affect the solubility of iron phosphate dihydrate by the formation or dissociation of coordination species, which could further accelerate the phase transformation from the amorphous iron phosphate dihydrate to orthorhombic iron phosphate dehydrate by dissolution–recrystallization mechanism.The high dependences of the solubility of iron phosphate materials on H_3PO_4 concentration and temperature were also well predicted by calibration equations, which are meaningful for quantitatively understanding the precipitation process and sequential crystalline structure transformation and pursuing a rational strategy for synthesizing specific iron phosphate materials.
The axial and radial profiles of the gas holdup and bubble parameters in an external-loop airlift reactor of inner diameter 0.09 m and height 1.8 m were measured with the differential pressure method and dual-tip electrical conductivity probe at different superficial gas velocities.Air and water were used as the gas and liquid phases,respectively.The experimental data of the average and local gas holdups,bubble size and its distribution,bubble rising velocity,bubble frequency and gas-liquid interfacial area were obtained,and were analyzed based on the gas-liquid flow field and bubble-bubble interaction.The local gas holdup was correlated in terms of superficial gas velocity,axial height and radial position based on the experimental data.
The molecular interactions in the complex formation of two tartaric acid derivatives with di(2-ethylhexyl) phosphoric acid are investigated. The complex formation with a 1:1 stoichiometry between tartaric acid derivatives and D2EHPA can be obtained through UV-Vis titration, NMR chemical shifts and molecular dynamic simulations. Furthermore, the differences of the two complexes on the binding constants and strength of hydrogen bonds can also be determined. Such research will ideally provide insight into ways of regulating the complex forming properties of tartaric acid derivatives for composing or syn- thesizing new chiral resolving agents.
This paper presents the experimental results of liquid-liquid microflows in a coaxial microfluidic device with mass transfer.Three working systems were n-butanol + phosphoric acid(PA) + water,methyl isobutyl ketone(MIBK) + PA + water,30% kerosene in tri-n-butylphosphate(TBP) + PA + water.The direction and intensity of mass transfer were adjusted by adding PA in one of two phases mutual saturated in advance.When PA transferred from the organic phase to the aqueous phase,tiny aqueous droplets may generate inside the organic phase by mass transfer inducement to form a new W/O/W flow pattern directly on some special cases.Once the PA concentration was very high,violent Marangoni effect could be observed to throw part of organic phase out of droplets as tail.The interphase transfer of PA could expand the jetting flow region,in particular for systems with low or medium inter-facial tension and when the mass transfer direction was from the aqueous phase to the organic phase.
