B2O3 Boron oxide

Bulk boron oxide was found to be much more acidic than basic [168], When SO2 adsorption microcalorimetry was used, no basic sites were observed, but some phy-sisorption occurred. Ammonia and pyridine adsorption microcalorimetry were used to characterize the acidity of B2O3. Boron oxide displays an initial heat for NH3 adsorption of 80 kJ/mol and can adsorb irreversibly a large amount of ammonia. The number of active sites determined by pyridine adsorption and the corresponding integral heats were found to be much lower than those determined by using ammonia. 

AI3-51845 Boric acid (HBO2), anhydride Boric anhydride Boric oxide Boric oxide (B2O3) Boron oxide Boron sesquioxide Caswell No. 109B Diboron trioxide EINECS 215-125-8 Fused boric acid HSDB 1609. Used in production of boron, heat-resistant glassware, fire-resistant additive for paints, electronics, liquid encapsulation techniques, herbicide. White crystals mp = 450° bp = 1860° d = 2.46 soluble in H2O (3 g/100 ml) LDso (mus orl) = 3163 mg/kg. Atomergic Chemetals Lancaster Synthesis Co. Noah Chem. u.S. Borax Inc. 

The industrial synthesis of BN is based on a two-stage process. In the first stage, conducted at approximately 900 °C, a boron source such as B2O3 (boron oxide) or H3BO3 (boric acid) is converted in a reaction with a nitrogen source (mostly melamine or urea, sometimes even ammonia [NH3]) to form amorphous BN ... 

The samples were analyzed for Na, Si, and A1 content by x-ray fluorescence spectroscopy. The extent of dealumination was found to vary for different lots of Zelon 900H. For a given lot, the extent of dealumination increased with acid extraction time. The extent of dealumination was controlled by adjusting the extraction time. Boron oxide (1.50 g B2O3) was dissolved in 140 mL of 0.25 M KOH. Dealuminated mordenite (25 g Si/Al = 64) was added to the solution, and the pH was adjusted to 13 by addition of KOH. The resulting suspension was stirred at 80°C for 24 h in a Teflon lined Parr pressure vessel. The product was separated by filtration, thoroughly washed with deionized water, and dried at 120°C. The composition of the product was determined by XRF and atomic absorption spectroscopy. 

Figure 7 Structural representation of boron oxide (B2O3) glass. The giant 2-D skeleton is formed by BO3 triangles sharing comers. Specific B3O3O3/2 boroxol groups can be present in the structure...

Boron oxide, B2O3, can be reduced by C above 1600°C. An electric arc furnace is used for large-scale production. Since this process takes place in two steps with CO as an intermediate, an overpressure of CO is necessary during the initial reaction. A final heating in vacuum at higher T is needed for purification. 

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