Boron trioxide

Boron does not occur free in nature in minerals, it occurs as borates, for example, kernite. Na2B407.4H2O. and borax. Na2B407. IOH2O there are extensive deposits of these in the USA. Boron can be obtained by heating boron trioxide with magnesium ... 

Boron trioxide, B2O3 is the anhydride of boric acid, H3BO3 and can be prepared by heating the acid ... 

Boron trioxide is not particularly soluble in water but it slowly dissolves to form both dioxo(HB02)(meta) and trioxo(H3B03) (ortho) boric acids. It is a dimorphous oxide and exists as either a glassy or a crystalline solid. Boron trioxide is an acidic oxide and combines with metal oxides and hydroxides to form borates, some of which have characteristic colours—a fact utilised in analysis as the "borax bead test , cf alumina p. 150. Boric acid. H3BO3. properly called trioxoboric acid, may be prepared by adding excess hydrochloric or sulphuric acid to a hot saturated solution of borax, sodium heptaoxotetraborate, Na2B407, when the only moderately soluble boric acid separates as white flaky crystals on cooling. Boric acid is a very weak monobasic acid it is, in fact, a Lewis acid since its acidity is due to an initial acceptance of a lone pair of electrons from water rather than direct proton donation as in the case of Lowry-Bronsted acids, i.e. 

Both boron and aluminium chlorides can be prepared by the direct combination of the elements. Boron trichloride can also be prepared by passing chlorine gas over a strongly heated mixture of boron trioxide and carbon. Like boron trifluoride, this is a covalent compound and a gas at ordinary temperature and pressure (boiling point 285 K). It reacts vigorously with water, the mechanism probably involving initial co-ordination of a water molecule (p, 152). and hydrochloric acid is obtained ... 

Oxidation of C12-C14 n-paraffms using boron trioxide catalysts was extensively studied for the production of fatty alcohols.Typical reaction conditions are 120-130°C at atmospheric pressure. ter-Butyl hydroperoxide (0.5 %) was used to initiate the reaction. The yield of the alcohols was 76.2 wt% at 30.5% conversion. Fatty acids (8.9 wt%) were also obtained. Product alcohols were essentially secondary with the same number of carbons and the same structure per molecule as the parent paraffin hydrocarbon. This shows that no cracking has occurred under the conditions used. The oxidation reaction could be represented as ... 

AITs for ethylene-oxygen mixtures at 1 bar in stainless steel were reduced by 30-40°C by coating the vessel walls with boron trioxide. 

Arsenic trioxide reacts violently and nitrogen oxide ignites in excess fluorine. Bubbles of sulfur dioxide explode separately on contacting fluorine, while addition of the latter to sulfur dioxide causes an explosion at a certain concentration [1], Reaction of fluorine with dinitrogen tetraoxide usually causes ignition [2], Interaction with carbon monoxide may be explosive. Anhydrous silica incandesces in the gas, and interaction with liquid fluorine at — 80°C is explosive [3,4], Boron trioxide also incandesces in the gas [3],... 

Boron trifluoride is most important of all the halides of boron and is obtained as a colourless highly pungent gas by heating boron trioxide with CaF2 and Cone. H2S04. 

Boron trifluoride is a colourless, reactive gas which can be prepared by heating boron trioxide and fluorspar with concentrated sulphuric acid,... 

The generally acidic materials in this group may function as oxidants, some rather powerful, under appropriate conditions. Individually indexed compounds are Arsenic pentaoxide, 0106 Arsenic trioxide, 0105 Boron trioxide, 0170 Carbon dioxide, 0557 f Carbon monoxide, 0555... 

Synonyms Boric anhydride boron sesquiox-ide boron trioxide fused boric acid... 

Electrolytic reduction and thermal decomposition have not yet been apphed in large scale commercial methods. Electrolysis of alkali or alkaline earth borates produces boron in low purity. Electrolytic reduction of fused melts of boron trioxide or potassium tetrafluroborate in potassium chloride yield boron in high purity. Also, boron tribromide or boron hydrides may be thermally dissociated hy heating at elevated temperatures. 

Boron trichloride can be prepared by high temperature chlorination of boron trioxide, boric acid, metal borates or other boron compounds. Chlorine, hydrogen chloride, phosgene, silicon tetrachloride, metal chlorides, carbon... 

Borosilicate pigments [59794-15-19] usually contain calcium or zinc ions in a matrix of silicon dioxide and boron trioxide, x (Ca,Zn)-y Si04 zB03. Aqueous slurries of this white pigment are alkaline (pH > 9). Borosilicate pigments are... 

Proceed as for silicon, using 50g of dry boron trioxide, 75g of sulfur, and lOOg of aluminum. About 7.5g of black metallic crystals (which scratch glass) are obtained. The thinnest crystals show a dark-red color by transmitted light... 

Substances that are ordinarily deliquescent are sulfuric add (concentrated), glycerol, calcium chloride crystals, sodium hydroxide (solid), and 100% ethyl alcohol. In an enclosed space, these substances deplete the water vapor present to a definite degree. Other substances are used to accomplish this end by chemical reaction, e.g.. phosphorus pentoxide (forming phosphoric acid), and boron trioxide (forming boric acid). Water is absorbed from nonmiscible liquids by addition of such substances as anhydrous sodium sulfate, potassium carbonate, anhydrous calcium chloride. and solid sodium hydroxide. The converse phenomenon is known as efflorescence. 

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