Hydrate barium hydroxide

Barium hydroxide (hydrate) [Ba(OH)2] exists in several forms and has many uses in oil and grease additives, water treatment, vulcanization of rubber, and the manufacture of soaps, beet sugar, glass, and steel. 

A new and convenient synthesis of 3-(substituted)-2,4,6-triphenylverdazyls involves crown ether assisted solid-liquid phase transfer catalysis of reactions of triphenylformazans with alkyl bromides (or 1-alkylbenzotriazoles) also using barium hydroxide hydrate catalysis (Scheme 8) [94CJC1849]. 

Internally chilled rotating drum crystallizers (see Figure 8.24) are normally associated with melt crystallization (section 8.2), but have also found occasional application for crystallization from solution. Sodium sulphate and barium hydroxide hydrates, for example, have been produced commercially in this manner. 

Barium acetate [543-80-6] Ba(C2H202)2, crystallines from an aqueous solution of acetic acid and barium carbonate or barium hydroxide. The level of hydration depends on crystallization temperature. At <24.7°C the trihydrate, density 2.02 g/mL is formed from 24.7 to 41 °C barium acetate monohydrate [5908-64-5] density 2.19 g/mL precipitates and above 41 °C the anhydrous salt, density 2.47 g/mL results. The monohydrate becomes anhydrous at 110°C. At 20°C, 76 g of the monohydrate dissolves in 100 g of water. Barium acetate is used in printing fabrics, lubricating grease, and as a catalyst for organic reactions. 

Barium hydroxide is the strongest base and has the greatest water-solubility of the alkaline-earth elements. Barium hydroxide (barium hydrate, caustic baryta) exists as the octahydrate [12230-71 -6], Ba(OH)2 8H20, the monohydrate [22326-55-2], Ba(OH)2 H20, or as the anhydrous [17194-00-2] material, Ba(OH)2. The octahydrate and monohydrate have sp gr 2.18 and 3.74, respectively. The mp of the octahydrate and anhydrous are 77.9 °C and 407°C, respectively. 

BaS hydrolyzes to Ba(OH)2 and barium hydrosulfide. Cooling of an aqueous BaS solution can precipitate the double salt barium hydroxide sulfide hydrate [42821-46-3J, Ba(OH)2 Ba(SH)2 -xH O. 

Baryum, n. barium, -chlorhydrat, n. barium chloride. -hydrat, n. barium hydroxide, -hyperoxyd, n. barium peroxide, barium dioxide. -jodid, n. barium iodide, -lack, m. barium lake, -oxydhydrat, n. barium hydroxide. -platincyaniir, n. barium cyano-platinite, barium cyanoplatinate(II). -rho-danid, n. barium thiocyanate, -salz, n. bar ium salt. 

Aldol condensation of acetone is a well-known base-catalyzed reaction, and barium hydroxide is one of the catalysts for this reaction mentioned in textbooks. A family of barium hydroxide samples hydrated to various degress determined by the calcination temperature (473, 573, 873, and 973 K) of the starting commercial Ba(OH)2 8H2O were reported to be active as basic catalysts for acetone aldol condensation (282,286). The reaction was carried out in a batch reactor equipped with a Soxhlet extractor, where the catalyst was placed. The results show that Ba(OH)2 8H2O is less active than any of the other activated Ba(HO)2 samples, and the Ba(OH)2 calcined at 473 K was the most active and selective catalyst for formation of diacetone alcohol, achieving nearly 58% acetone conversion after 8h at 367 K in a batch reactor. When the reaction temperature was increased to 385 K, 78% acetone conversion with 92% selectivity to diacetone alcohol was obtained after 8h. The yield of diacetone alcohol was similar to that described in the literature in applications with commercial barium hydroxide, but this catalyst required longer reaction times (72-120 h) (287). No deactivation of the catalyst was observed in the process, and it could be used at least 9 times without loss of activity. 

If hydrated barium hydroxide [Ba(OH)2 - 8H2O] is used in the thimbles this becomes dehydrated after one run the anhydrous form is just as satisfactory and may be used over and over again. 

A 500ml round-bottomed flask is fitted with an inlet tube for nitrogen and an exit delivery tube leading into a dish of water. Twenty grams of barium hydroxide 8-hydrate, 5g of yellow phosphorus, and 200 ml of water are placed in the flask and a steady stream of nitrogen is led in to dis-... 

To 33.2g of pure (recrystallized) sulfamic acid (No. 92) in 250ml of water are added 54.0g of pure barium hydroxide 8-hydrate. When all the solids have dissolved, any precipitate of barium sulfate is filtered off and the clear filtrate evaporated in vacuo at room temperature with the water pump. Successive crops of crystals are isolated, washed with 95% alcohol and the mother liquor with rinsings is further evaporated. Depending on the completeness of the water removal, yields of over 90% are readily attained. 

The procedure to be followed is the same as for the calcium salt except that about 180g of barium hydroxide 8-hydrate is employed, instead of the slaked lime. As the former is more soluble, some care should be exercised not to add too great an excess because the quantity of slurry... 

Barium hydroxide octahydrate, Ba(OH)2 8 H20, is a crystalline compound that contains eight water molecules clustered around the barium atom. We ll learn more about hydrates in Section 14.15. 

Bassam Z. Shakhashiri, "Endothermic Reactions of Hydrated Barium Hydroxide and Ammonium Salts," Chemical Demonstrations, A Handbook for Teachers of Chemistry, Vol. 1 (The University of Wisconsin Press, Madison, 1983) pp. 10-12. 

Pure barium peroxide hydrate Ba02-8H20 is precipitated when barium hydroxide is added to a hydrogen peroxide solution. Hydrogen peroxide is not a stable substance its solution decomposes slowly in any event into oxygen and water. This decomposition is greatly hastened by suspended solid matter and by hydroxyl ions in the following preparation one should work to minimize the amount of this decomposition. 

After removal of impurities by filtration, a solution of barium hydroxide is added whereby pure, crystalline barium peroxide hydrate Ba02-8H20 is precipitated. 

Pour, in a thin stream, with constant stirring, the hydrogen peroxide solution into the barium hydroxide solution in the 2-liter bottle. Let the flaky barium peroxide hydrate settle and then collect it on a suction filter. As soon as the water is drawn out, shut off the suction, wash with 15 cc. cold water, press the solid into a compact cake, and again suck dry. Do not draw any quantity of air through the product. Wrap the crystals in paper towels and dry them according to Note 9 (6), page 15. Preserve the product in a 4-ounce cork-stoppered bottle. 

Some types of ionic compounds can absorb water so that each formula unit is attached to a specific number of water molecules. They are called hydrates. Ba0H2 8H20 is called barium hydroxide octahydrate. CaS04 2H20 is called calcium sulfate dihydrate. Can you see the pattern Try naming MgS04 7H20. Use Table 3.8 to help you. You will learn more about hydrates in Chapter 6. 

A hydrate of barium hydroxide, Ba(0H)2-xH20, is used to make barium salts and to prepare certain organic compounds. Since it reacts with C02 from the air to yield barium carbonate, BaC03, it must be stored in tightly stoppered bottles. 

From the conductivity in solutions which are not extremely dilute, it appears that in numerous other cases also ion pairs are formed (Bjerrum), that is to say, combinations of ions, each still with its hydration sheath and which thus do not correspond with molecules. It is especially the higher valency ions from the nature of things which exhibit this phenomenon thus this pair formation occurs, for example, in the alkali sulphates, alkaline earth nitrates and barium hydroxide through the formation of [MS04], [MN03]+ and [Ba(OH)] ions, furthermore [Ce4+(OH)-]3+, [Fe3+(OH)-]2+. 

All technical processes for the synthesis of hydrazine yield either hydrazine in aqueous solution or hydrazine hydrate. Most applications can use hydrazine hydrate, but for some applications, for example, rocket propulsion, anhydrous hydrazine is necessary. The water can be removed by a chemical reaction followed by distillation or by azeotropic distillation with an auxiliary fluid. As water binding chemicals, calcium carbide, sodium hydroxide, calcium oxide, calcium hydride, barium oxide, barium hydroxide, and barium pemitride Ba3N4 have been used. The use of sodium or calcium metal and sodium amide is best avoided because of the formation of explosive hydrazides. Starting from hydrazine hydrate (64% hydrazine), sodium hydroxide is generally used... 

A mixture of 106 g. (1.0 mole) of o-xylene and 107 ml. of concentrated sulfuric acid is stirred and heated on a steam bath for 1.5 hours, and the resulting solution is dissolved in 1.5 1. of water. A solution of 473 g. of hydrated barium hydroxide in 750 ml. of water is added, and the resulting neutral solution is filtered hot and cooled to 50-60°. To this is added a solution of 192 g. (1.20 moles) of bromine and 200 g. of barium bromide in 700 ml. of water. (Hood.) The mixture is held at 50-60° for 15 hours, after which it is cooled and the precipitated barimn bromo-o-xylenesulfonate removed by filtration, washed with water, and dried. The yield of the salt (somewhat impure) is 63%. 

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