Potassium hydroxide monoxide

The reaction is displaced to the right by dissociation of sodium hydride and Hberation of hydrogen. This dissociation is favored under vacuum or when the reaction 2one is swept with an inert gas to remove the hydrogen (24,25). In this manner, sodium monoxide substantially free of sodium and sodium hydroxide is produced. In the more compHcated reaction between sodium metal and anhydrous potassium hydroxide, potassium metal and sodium hydroxide are produced in a reversible reaction (42,43) ... 

Chloroform and water at 0°C form six-sided crystals of a hydrate, CHCl I8H2O [67922-19-41which decompose at 1.6°C. Chloroform does not decompose appreciably when in prolonged contact with water at ordinary temperature and in the absence of air. However, on prolonged heating with water at 225°C, decomposition to formic acid, carbon monoxide, and hydrogen chloride occurs. A similar hydrolysis takes place when chloroform is decomposed at elevated temperature by potassium hydroxide. 

Potassium formate is produced slowly by absorption of carbon monoxide by 50 to 80 wt% aqueous solution of potassium hydroxide at 100 to 200°C and a CO partial pressure over 7 atm. 

Other reported syntheses include the Reimer-Tiemann reaction, in which carbon tetrachloride is condensed with phenol in the presence of potassium hydroxide. A mixture of the ortho- and para-isomers is obtained the para-isomer predominates. -Hydroxybenzoic acid can be synthesized from phenol, carbon monoxide, and an alkali carbonate (52). It can also be obtained by heating alkali salts of -cresol at high temperatures (260—270°C) over metallic oxides, eg, lead dioxide, manganese dioxide, iron oxide, or copper oxide, or with mixed alkali and a copper catalyst (53). Heating potassium salicylate at 240°C for 1—1.5 h results in a 70—80% yield of -hydroxybenzoic acid (54). When the dipotassium salt of salicylic acid is heated in an atmosphere of carbon dioxide, an almost complete conversion to -hydroxybenzoic acid results. They>-aminobenzoic acid can be converted to the diazo acid with nitrous acid followed by hydrolysis. Finally, the sulfo- and halogenobenzoic acids can be fused with alkali. 

The compound Ru3H(CO)9(C2-t-Bu) (1.243 g, 1.950 mmol) is treated with alcoholic potassium hydroxide (17.5mL of 0.128 M, 2.24 mmol) followed by mercury(II) iodide (0.444 g, 0.978 mmol) as outlined in the procedure in Section (B.l). The resulting solution is allowed to stir under a carbon monoxide atmosphere until a bright yellow precipitate forms. The reaction time is typically 30 to 45 min. Upon precipitation, the reaction mixture is evaporated to dryness under reduced pressure. The resulting residue is washed first with 50 mL of absolute ethanol and then with 25 mL of dichloromethane. The remaining yellow residue is recrystallized from hot THF. Yield 1.16-1.20 [81-84% yield based on Ru3H(CO)9(C2-t-Bu)]. 

The monoxide has been variously described, according to the method of preparation, as a black powder, or glistening crystals, or beautiful black cubes. Its density varies from 6 3 to 6-7, and it is a good conductor of electricity. On being heated in air it oxidises readily to the pentoxide with considerable evolution of heat. It dissolves in hydrofluoric acid and hydrochloric acid with evolution of hydrogen, and a pentavalent niobium salt is formed in solution. It is also dissolved by boiling potassium hydroxide to form potassium niobate. This behaviour of niobium monoxide towards acids and alkali indicates that divalent salts of niobium are too unstable to exist. A divalent chloride of tantalum has, however, recently been isolated (see p. 192). 

The reaction has been shown to involve a stereospecific syn-addition with respect to the dienophile. For example, the reaction of 2,3-dimethylbuta-1,3-diene with maleic anhydride gives cis-l,2,3,6-tetrahydro-4,5-dimethylphthalic anhydride (Expt 7.20). An example of the use of a quinone as the dienophile is provided by the synthesis of cis-1,4,4a,9a-tetrahydro-2,3-dimethyl-9,l0-anthra-quinone which upon dehydrogenation (most simply by the action of oxygen upon its solution in alcoholic potassium hydroxide) yields 2,3-dimethylanthra-quinone (Expt 7.21). Tetraphenylcyclopentadienone (tetracyclone) readily undergoes the addition of dienophiles, such as maleic anhydride, to give an adduct, which then extrudes a molecule of carbon monoxide on heating, as in the preparation of 3,4,5,6-tetraphenyldihydrophthalic anhydride (Expt 7.22). 

Carbon dioxide may be removed from commercial carbon monoxide by scrubbing with dry potassium hydroxide or a commercial carbon dioxide absorbent such as Caroxite. A procedure for the preparation and purification of carbon monoxide is given by W. L. Gilliland and A. A. Blanchard.6... 

One of the first fuel cell designs was low-temperature alkaline fuel cells (AFCs) used in the U.S. space program. They served to produce both water and electricity on the spacecraft. Some of their disadvantages are that they are subject to carbon monoxide poisoning, are expensive, and have short operating lives. The AFC electrodes are made of porous carbon plates laced with a catalyst. The electrolyte is potassium hydroxide. At the cathode, oxygen forms hydroxide ions, which are recycled back to the anode. At the anode, hydrogen gas combines with the hydroxide ions to produce water vapor and electrons that are forced out of the anode to produce electric current. 

It seems to be necessary to convert the primary fuel into hydrogen or carbon monoxide first after this the cell functions well. The best-known application is in the combustion of hydrogen in aqueous potassium hydroxide electrolyte with nickel electrodes at 200°C, as used in the Apollo series space flights. 

The suggestion has also been made that perearbomc acid, H2C206, may be formed intermediately, since by allowing a flame of the moist monoxide to impinge on a cold, dilute solution of cobalt chloride and potassium hydroxide, a precipitate is obtained closely resembling that yielded on adding potassium perearbonate to a solution of cobalt chloride.1 The combustion would thus presumably proceed as follows ... 

Osmium Dihydroxide, Hydrated Osmium Monoxide, Os(OH)2, is prepared as an unstable, bluish black precipitate on warming osmium sulphite with a concentrated solution of potassium hydroxide.2... 

Hydrated Platinum Monoxide, Pt0.2H20, is obtained in a more or less impure condition by the addition of warm potassium hydroxide solution to platinous chloride.4 The pure hydrated oxide, however, may be obtained8 by boiling a solution of potassium chlor-platinite with the calculated amount of sodium hydroxide solution. The hydrated oxide separates out as a dark precipitate, which is readily oxidised by exposure to air, so that it is necessary to wash and dry it in an atmosphere of carbon dioxide. It retains its combined water very tenaciously, and cannot be completely dehydrated without partial decomposition. 

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