Highly Active Benzotriazolium Ionic Liquid-modified Periodic Mesoporous Organosilica Supported Samarium/Lanthanum Nanoparticles for Sustainable Transformation of Carbon Dioxide to Cyclic Carbonates

A novel type of multifunctional nanocatalysts (La-/Sm-PMO-ILCl) based on the immobilization of benzotriazolium ionic liquid and further incorporation of samarium acetate or lanthanum acetate onto periodic mesoporous organosilica were afforded for the cycloaddition of CO2 and epoxides to produce cyclic carbonates. In consequence of the intramolecular synergistic effect between samarium sites of periodic mesoporous organosilica and homogeneously dispersed basic sites of ionic liquid, the powerful catalyst Sm-PMO-ILCl offered superior catalytic performance with ultra high yields and selectivities in the cycloaddition reaction without the addition of any solvent and cocatalyst. Moreover, the catalyst Sm-PMO-ILCl could be easily recovered by filtration and reused for at least five runs without any significant loss of its catalytic activity. Resumen. Se prepararon nuevos nano catalizadores (La-(Sm-PMO-ILC1) por la vía de inmovilización del líquido iónico benzotriazolium y adición se acetato de samario o acetato de lantano en organosilice mesoporosa. Los catalizadores se evaluaron en la ciclo adición de CO2 y epóxidos para producir carbonatos cíclicos. El efecto sinérgico intramolecular entre los sitios de samario de la organosilice y los sitios básicos del líquido iónico homogéneamente distribuidos inducen una alta actividad catalítica en el catalizador Sm-PMO-ILC1. Así, con este catalizador se obtuvo alta conversión y selectividad en la reacción de ciclo adición, sin agregar solvente ni co-catalizador. Además, el catalizador Sm-PMO-ILC1 podría recuperarse fácilmente por filtración y reusado por al menos 5 corridas sin pérdida significativa de su actividad catalítica.

Rare Earth-Based Compounds as Inhibitors of Hot-Corrosion Induced by Vanadium Salts

In this study, the performance evaluation of lanthanum compounds as corrosion inhibitors of vanadium salts was performed. The inhibitors tested were lanthanum acetate and La2O3. The performance of the inhibitors was tested using sodium metavanadate (NaVO3) as a corrosive medium at 700, 800, and 900 °C. The corrosion inhibitory effect was evaluated on the corrosion process of 304H stainless steel. The corrosion rate of the steel was determined by the mass loss technique after 100 h of immersion in the corrosive salt with and without the addition of the corrosion inhibitor. The results show that lanthanum compounds act as corrosion inhibitors of vanadium salts. The inhibitory effect increases by increasing the concentration and tends to decrease when increasing the test temperature. Lanthanum compounds act as excellent corrosion inhibitors due to their ability to stabilize vanadium cations. Vanadium is stabilized by forming a new compound, lanthanum vanadate (LaVO4), with a melting point much higher than the compounds formed when Mg or Ni compounds are used as corrosion inhibitors.

Lanthanum Acetate Inhibits Vascular Calcification Induced by Vitamin D3 Plus Nicotine in Rats

Lanthanum, a rare earth element, has been used to decrease serum phosphorus level in patients with chronic renal disease and hyperphosphatemia. We aimed to observe the effect and mechanism of two doses of lanthanum acetate (375 and 750 mg/kg/day) on vascular calcification induced by vitamin D3 plus nicotine treatment in rats for 4 weeks. As compared with control rats, rats with calcification showed widespread calcified nodules and irregular elastic fibers in calcified aorta on von Kossa calcium staining and increased aortic calcium and phosphorus contents, alkaline phosphatase (ALP) activity and bone-related protein expressions for osteopontin (OPN) and type III sodium dependent phosphate cotransporter Pit-1 (Pit-1). After treatment with either dose of lanthanum acetate, the calcified nodules and degree of irregular elastic fibers decreased in aortas. Lanthanum acetate at 750 mg/kg/day was more effective than 375 mg/kg/day in lessening vascular calcification by significantly reducing plasma phosphorus level, calcium × phosphorus product and ALP activity, by 30.3%, 28.6%, and 68.6%, respectively; reducing aortic phosphorus and calcium contents and ALP activity, by 48%, 53.1%, and 63.5% (all P < 0.01), respectively; reducing aortic mRNA level of OPN and Pit-1, by 55.8% ( P < 0.01) and 38.8% ( P < 0.05) and protein level of OPN and Pit-1, by 37.2% and 27.2% (both P < 0.01), respectively; and increasing carboxylated matrix Gla-protein (MGP) protein expression by 33.7% ( P < 0.05), as compared with rats treated with vitamin D3 and nicotine alone. Lanthanum acetate could effectively inhibit the pathogenesis of vascular calcification.