Grignard‐Type Arylation of Aldehydes via a Rhodium‐Catalyzed C?H Activation under Mild Conditions

An efficient Grignard‐type arylation of aldehydes via aryl C H activation was achieved under mild conditions catalyzed by rhodium. The reaction provides an easy access to a wide variety of benzyl alcohols and can tolerate various functional groups as well as air and water.     

A pilot scale study of reverse osmosis for the purification of condensate arising from distillery stillage concentration plant

Reverse osmosis (RO) is an interesting process to eliminate small organic solutes (carboxylic acids and alcohols) from distillery condensates before recycling them into the fermentation step. This work investigates the influence of transmembrane pressure, pH and volume reduction factor (VRF) on the efficiency of reverse osmosis treatment of condensate from distillery stillage concentration at pilot scale using three pre-selected membranes (CPA2 and ESPA2 from Hydranautics, BW30 from DOW). Performances were assessed according to permeate flux, solutes rejection and abatement of fermentation inhibition. Transmembrane pressure increase leads to an increase of these three parameters with a plateau for rejections and abatement at 20 bar; however, in order to comply with membranes manufacturer's recommendations and to limit or delay polarization and fouling, it was decided to keep the permeate flux below a value of 30 L h⁻¹ m⁻². This corresponded to a maximum pressure of 10 bar for CPA2 and ESPA2 membranes and 25 bar for BW30 membrane. pH increase leads to a diminution of permeate flux and an increase of carboxylic acids rejection whatever the membrane; nevertheless, no abatement of fermentation inhibition is observed. Increasing VRF provokes a decrease of the permeate flux. Although local rejections are stable, the mean rejection assessed with the raw condensate (feed) and the mean permeate decreases. However, the fermentation inhibition remains under 10% up to a VRF of 8. BW30 membrane exhibits the highest rejections and inhibition abatement. On the basis of the pilot scale results with the BW30 membrane, a preliminary estimation of the membrane area is proposed for an industrial plant with 100 m³ h⁻¹ of condensate flow rate and the optimized parameters (pressure 25 bar, no pH modification, VRF 4 and 8).     

Thermodynamic and kinetic studies of the MgCl2‐NH4Cl‐NH3‐H2O system for the production of high purity MgO from calcined low‐grade magnesite

To improve the overall sustainability of MgO‐based refractory production, a novel process to produce high purity MgO from calcined low‐grade magnesite in ammonium chloride solution was developed. The process was designed on the basis of the phase equilibria of the NH₄Cl‐MgCl₂‐NH₃‐H₂O system obtained using the Mixed Solvent Electrolyte model embedded in OLI software. The optimum calcination temperature of low‐grade magnesite was determined to be 650°C in terms of the conversion ratio of magnesium and calcium in the leaching experiments. An apparent activation energy of Mg extraction was 30.98 kJ/mol, which is slightly lower than that of Ca leaching. An empirical kinetic model of magnesium extraction was also developed to describe the effects of NH₄Cl concentration, particle size of calcined magnesite, and solid‐to‐liquid ratio on the extent of extraction of magnesium. At leaching time of 10 min, the leachate with high Mg/Ca molar ratio was obtained. Then, MgO with a purity of 99.09% was produced through the decomposition of intermediate 4MgCO₃·Mg(OH)₂·4H₂O. © 2015 American Institute of Chemical Engineers AIChE J, 61: 1933–1946, 2015