Reactions with barium oxide

Barium oxide and sodium hydride are more potent catalysts than silver oxide. With barium oxide catalysis, reactions occur more rapidly but O-acetyl migration is promoted. With sodiun hydride, even sterically hindered groups may be quantitatively alkylated but unwanted C-alkylation Instead of, or in addition to, 0-alkylatlon is a possibility. Sodium hydroxide is a suitable catalyst for the alkylation of carboxylic acids and alcohols [497J. 

Barium carbide (acetylide), BaC2 black solid, by reaction of barium oxide and carbon at electric furnace temperatures, reacts with H20 yielding acetylene gas and barium hydroxide. 

At the equilibrium point of this reaction the partial pressure of carbon monoxide is many times that of the carbon dioxide thus it would be much above 1 atmosphere, and carbon monoxide would escape from the crucible. With excess powdered charcoal in the crucible, therefore, both reactions would continue to run until all the barium carbonate had changed to barium oxide. Carbon monoxide does not react with barium oxide. 

Zinc 2-ethylhexanoate was prepared in refluxing toluene from the reaction of 2-ethylhexanoic acid with zinc oxide. The lead salt was prepared in methanol by the reaction of lead acetate with 2-ethylhexanoic acid. The reaction of barium oxide with 2-ethylhexanoic acid in toluene provided the barium salt. 

An extensive series of phases of general formula Ba Ti5,0 +2y are formed from the reaction of Ti02 with barium oxide. The simplest, BaTiOs, is known as barium titanate. These materials are of interest because of their ferroelectric properties, which result from the differences in the relative sizes of the Ba andTi ions. The Ti ions are located between six Ba ions, which occupy octahedral positions. However, the Ti ions are small compared to the Ba and so are free to move within their octahedral Ba holes . 

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 Central nervous system effects at high concentrations. An asphyxiant. Flammable gas. Highly dangerous fire hazard when exposed to heat or flame can react vigorously with oxidizers. Explosive in the form of vapor when exposed to heat or flame. Explosive reaction with CIO2. Violent exothermic reaction with barium peroxide + heat. To fight fire, stop flow of gas. When heated to decomposition it emits acrid smoke and irritating fumes. 

Calculate the enthalpy change for the reaction of barium oxide with carbon dioxide to yield barium carbonate. 

BARIUM SULFIDE (21109-95-5) BaS Flammable solid. Oxidizes in dry air. Contact with acid, acid fumes, moisture, steam, or moist air causes decomposition with the formation of toxic and flammable hydrogen sulfide gas. Evolved gas can form explosive mixtures with air and may cause spontaneous ignition or explosion. Violent reaction with strong oxidizers, calcium chlorate calcium nitrate chlorine dioxide phosphorus(V) oxide strontium chlorate strontium nitrate. Incompatible with lead dioxide, potassium chlorate, potassium nitrite may explode at elevated temperatures. On small fires, use smothering quantities of dry chemical powder, dry clay, dry groimd limestone (CaCOj), dry soda ash,dry sand or approved Class D extinguishers, do not use water, foam, or hydrous agents. 

DICHLOROETHANE or 1,1-DICHLOROETHANE (75-34-3) C2H4CI2 Forms explosive mixture with air [explosion limits in air (vol %) 5.6 to 11.4 flash point 10°F/-12°C autoignition temp 856°F/458°C Fire Rating 3]. Violent reaction with strong oxidizers, potassium powdered metals alkaline earth (barium, calcium, strontium sometime magnesium is included) and alkali metals (lifliium, sodium. 

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