A new protocol to synthesize 1,4-dihydropyridines by using 3,4,5-trifluorobenzeneboronic acid as a catalyst in ionic liquid: synthesis of novel 4-(3-carboxyl-1H-pyrazol-4-yl)-1,4-dihydropyridines

We compare the effects of BN coatings on antioxidation ability and field emission properties of SiC nanowires. Under oxidizing condition, SiC nanowires without BN coatings are cracked into nanoparticles or almost fully converted into SiO2 nanowires at the temperature above 800 K, depending on the crystallization degree of SiC nanowires. The BN coatings effectively improve the antioxidation ability of SiC nanowires due to the excellent chemical stability of BN at high temperature. At a temperature higher than 1273 K, the coated SiC nanowires still exhibit strong oxidation resistance. For the effect on electron emission, the BN coatings also reduce the turn-on field of SiC nanowires from larger than 10 V/μm to lower than 6 V/μm. The explanation for the improvement of field emission characteristics has been presented.

Effect of BN coatings on oxidation resistance and field emission of SiC nanowires

Boron removal from wastewaters of geothermal plant was studied using N-glucamine type chelating resins so-called Diaion CRB 01, Diaion CRB 02, Purolite S 108. The batch-mode sorption studies was performed to obtain the optimum amount of resins for boron removal from geothermal wastewater. The boron on the resin was quantitatively eluted with 5% H2SO4. A column-mode study was performed using weak base ion exchange resin Diaion WA 30 for the separation of boron from H2SO4 solution.

Removal and recovery of boron from geothermal wastewater by selective ion exchange resins. I. Laboratory tests

Column sorption–elution studies for boron removal were performed using N-glucamine-type chelating ion-exchange resins Diaion CRB 02 Purolite S 108. The breakthrough curves were obtained as a function of resin type and feed flow rate. Boron was effectively removed from the wastewater of Kizildere, Turkey, geothermal power plant by passing it through the resins Diaion CRB 02 and Purolite S 108 at a space velocity of 25 bed volumes per hour. The boron on the resins was quantitatively eluted with 0.25 M H2SO4 solution. The resin Diaion CRB 02 was used to study the recycle use of resin for boron removal from the wastewater of Kizildere geothermal power plant. The capacity of Diaion CRB 02 remained constant after three sorption–elution–washing–regeneration cycles.

Roy M. Adams

Papers

Boron, Metallo-Boron Compounds and Boranes