Barium oxide, solubility

Sodium and potassium hydroxides. The use of these efficient reagents is generally confined to the drying of amines (soda lime, barium oxide and quicklime may also be employed) potassium hydroxide is somewhat superior to the sodium compound. Much of the water may be first removed by shaking with a concentrated solution of the alkali hydroxide. They react with many organic compounds (e.g., acids, phenols, esters and amides) in the presence of water, and are also soluble in certain organic liquids so that their use as desiccants is very limited... 

Compared to the hydroxides of calcium and strontiuim, barium hydroxide is the most water-soluble and also the strongest base. Additionally, barium hydroxide is more difficult to convert to the oxide by heating than are the corresponding hydroxides of calcium and strontium. Barium oxide is more readily converted to the peroxide than are the oxides of the other alkaline earths. 

Barium oxide, which can react directly with oxygen to give the peroxide (33), is soluble in methanol and ethanol forming the alkoxides (see... 

The threshold of a toxic dose in adult humans is about 0.2—0.5 g Ba the lethal dose in untreated cases is 3—4 g Ba, LD q about 66 mg/kg (47). The fatal dose of barium chloride for humans is reported to be between 0.8 and 0.9 g (0.55—0.60 g of Ba) (50). However, for most of the acid-soluble salts of barium, doses greater than 1 g have been tolerated (51). Lethal doses are summarized in Table 5. Dusts of barium oxide are considered potential dermal and nasal irritants (52). 

Strong bases include the oxides and hydroxides of the alkali metals and also the soluble oxides and hydroxides of the Group 2 metals, such as barium oxide and barium hydroxide. 

Barium carbonate decomposes to barium oxide and carbon dioxide when heated at 1,300°C. In the presence of carbon, decomposition occurs at lower temperatures. Barium carbonate dissolves in dilute HCl and HNO3 liberating CO2. Similar reaction occurs in acetic acid. The solid salts, chloride, nitrate and acetate that are water soluble may be obtained by evaporation of the solution. Dissolution in HF, followed by evaporation to dryness, and then heating to red heat, yields barium fluoride. 

Barium hydroxide decomposes to barium oxide when heated to 800°C. Reaction with carbon dioxide gives barium carbonate. Its aqueous solution, being highly alkahne, undergoes neutrahzation reactions with acids. Thus, it forms barium sulfate and barium phosphate with sulfuric and phosphoric acids, respectively. Reaction with hydrogen sulfide produces barium sulfide. Precipitation of many insoluble, or less soluble barium salts, may result from double decomposition reaction when Ba(OH)2 aqueous solution is mixed with many solutions of other metal salts. 

The barium oxide obtained in this way is not pure, but contains particles of charcoal as well as impurities coming from the mineral. It is very suitable, however, for the manufacture of barium hydroxide, into which it is converted by treatment with water. Barium hydroxide is extremely soluble in hot water, but sparingly so in cold water, from which it separates in flake-like crystals of the composition Ba(0H)2-8H20. 

SAFETY PROFILE Very toxic. Fire hazard by chemical reaction with easily oxidized materials. Explodes at 300°. Mixtures with sulfur are unstable storage hazards igniting immediately at 91 °C and after a 2-11 day delay period at room temperature. Incompatible with Al, As, C, Cu, metal sulfides, organic matter, P, and reducing materials. When heated to decomposition it emits toxic fumes of Br . See also BARIUM COMPOUNDS (soluble) and BROMINE. 

SAFETY PROFILE A poison by ingestion, subcutaneous, parenteral, and intravenous routes. An irritant to skin and eyes. When heated to decomposition it emits vety toxic fumes of NO. An oxidizer. Mixtures with finely divided aluminum-magnesium alloys are easily ignitable and extremely sensitive to friction or impact. Such mixtures are used in chemical photoflash applications. Incompatible with (Mg + Ba02 + Zn), Al, and Mg alloys. When heated to decomposition it emits toxic fumes of NOx. See also BARIUM COMPOUNDS (soluble) and NITRATES. 

SAFETY PROFILE A poison. Flammable by spontaneous chemical reaction, air, moisture, or acid fumes may cause it to ignite. For explosion and disaster hazards, see SULFIDES. To fight fire, use CO2, dry chemical. Reacts violently with phosphorus(V) oxide. Mixtures with lead dioxide, potassium chlorate, or potassium nitrite explode when heated. Incompatible with CI2O, Ca(N03)2, Sr(N03)2, Ca(C103)2, Sr(C103)2, (C103)2. See also BARIUM COMPOUNDS (soluble) and SULFIDES. 

Soluble compounds also irritate skin, eyes, and mucous membranes and can be absorbed following inhalation. Barium carbonate dust is a bronchial irritant. Barium oxide dust is a dermal and nasal irritant. 

Dimethyl sulfate-Barium oxide, see also Methyl iodide. Dimethyl sulfate in combination with barium oxide or barium hydroxide, Ba(0H)j-8H20, provides an effective method for the perraethylation of carbohydrates. Dimethyl sulfate is cheaper and sometimes superior to methyl iodide. Dimethylformamide is the usual solvent, but for carbohydrates only slightly soluble in this solvent dimethyl sulfoxide or a mixture of dimethyl sulfoxide and dimethylformamide is used. 

V.M. Ivenko, Determination of Solubility of Barium Oxide in BaC12-KCl-NaCl Eutectic by Potentiometric Method (Abstract of 10th All-Union Conference on Physics, Chemistry and Electrochemistry of Ionic Melts and Solid Electrolytes, Ekaterinbourg, Vol. 1. 1992) p. 74. 

CARBONIC ACID, BARIUM SALT (513-77-9) BaCOj Noncombustible solid. The aqueous solution is basic. Dissolves in most acids except sulfuric acid with release of CO2 gas. This could be dangerous in a confined space. Incompatible with finely divided alxuninum bromine trifluoride fluorine, 2-furanpercarboxylic acid magnesium, oxidizers, sodium azide silicon strong alkalis. Decomposes above 2372°F/1300°C, releasing COj and soluble barium salts including barium oxide. On small fires, use dry chemical powder (such as Purple-K-Powder), foam, or CO2 extinguishers. 

Barium monoxide Barium oxide Barium oxide (BaO) Barium protoxide Baryta Calcined baryta EINECS 215-127-9 Oxyde de baryum UNI 884, Dehydrating agent used as a drying agent for solvents, detergent for lubricating oils. White solid mp = 1920 bp = 2000° d = 5.98 soluble in H2O and dilute acids. Aiomergic Chemetals Hoechst Celanese Lancaster Synthesis Co. Noah Chem. 

In applying the Kuhn methylation to a pentasaccharide isolated from amylopectin a-limit dextrin, the maximum methoxyl content that French, E. E. Smith, and Whelan were able to obtain was 41.8X (theoretical, 49.5%). Quantitative analysis of the hydrolyzate showed that there was no undermethylation, and they concluded that it is essential to wash the product with cyanide after each methylation in order to eliminate chloroform-soluble impurities containing iodine. Kabat and coworkers found that a Kuhn methylation of hexosamines using silver oxide did not give interpretable results, but no problem was experienced when barium oxide was employed. 

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