Reactions with calcium hydride

When analyzing gaseous product of PVA decomposition in vacuum it was stated that main volatile products are H2O was defined quantitatively by the reaction with calcium hydride and by gasochromatography determination of hydrogen, being released during the reaction ... 

Reaction of calcium hydride (CaHJ with water. 

It was discovered that milling hexachlorobenzene with calcium hydride, to effect dechlorination, could give rise to explosive reaction, the conditions under which this happens were studied. 

A mixrnre of [RuCl2( -p-cymene)]2 (306 mg, 0.5 mmol), TsDPEN (366 mg, 1.0 mmol) and KOH (400 mg, 7.1 mmol) in 7 mL dichloromethane was stirred at room temperature for 5 min. On addition of water (7 mL) to the reaction mixmre, the colour changed from orange to deep purple. The purple organic layer was washed with 5 mL of water, dried with calcium hydride and concentrated to dryness to give the deep purple complex Ru(p-cymene)(TsDPEN) (455 mg, 75.8 % yield). 

Fig. 14. Kinetic curves of phenylglycidyl ether polymerization (6.67 mol I-1) under the action of dimethylamine (0.66 moll-1) at 343 K. 1 Pure (chromatography grade) undried phenylglycidyl ether, 2 dried with calcium hydride and dosed in dry argon, 3 precision drying and purification of the reagents in the reaction vessels, reagent dosed in vacuo 1+91...

Fluorodediazoniation in anhydrous hydrogen fluoride has been also applied to the synthesis of fluorinated heterocycles, especially pyridines 2. In this case, the reaction is more sensitive to the reaction conditions. For example, diazotization must be performed at lower temperatures than usual and the dediazoniation temperature must be raised slowly in order to obtain good yields. Workup is also important addition of dichloromethane prior to neutralization with ammonia32 as well as treatment of the organic phase with calcium hydride before distillation33 has been recommended, particularly for 4-fluoropyridines (4-fluoropyridine itself forms 4-fluoro-l-(4-pyridyl)pyridinium fluoride if not stored in a sealed tube with cooling33 or stabilized as the hydrochloride32). 

A common feature of the complexes [Nac Fe6(L13)6 ]Cl (36) and [Csc- Fe8(L13)g ]Cl (37, Sect. 6) is that one p -OT ethoxide donor of the triethano-lateamine ligands [N(CH2CH20)iCH2CH20 ] of (L13) 3 does not participate in the formation of the ferric wheels. They function solely as ligands for the coordi-native saturation of the iron centers. Therefore, any monoanionic donor, such as a chloride ion, could also be a candidate for this function. As expected, reaction of /V-alkyldiethanolamines H2L14 17 (38) with calcium hydride and iron(III) chloride yielded the neutral iron coronands [Fe6Cl6(L14 17)6] (39) with unoccupied centers (Scheme 14) [114-116],... 

Some examples are given in equations 4-71-4-75, and more are to be found in the sections dealing with the respective specific classes of organotin compounds which are formed. Cyclopentadiene can be both mono- and di-stannylated, and triphenylindenyltin has been obtained from indene (Section 9.3.1).116 Acetylene can be both mono-and di-stannylated,116-117 and the reaction of a diaminotin compound with acetylene gives a linear polymer.116-118 The acidity of sulphonylalkynes is sufficient to allow the reaction to be carried out with a tin alkoxide rather than a tin amide,119 and acetylenes can be stannylated with tributyltin oxide in benzene by dehydration with calcium hydride, or azeotropically.120... 

These ionic hydrides are all basic because they react with water to form hydroxide ions. When water is added by drops to lithium hydride, for example, lithium hydroxide and hydrogen are produced. The reaction of calcium hydride is similar. 

The reaction of calcium hydride with water can be used to prepare hydrogen gas ... 

SILVER FLUORIDE or SILVER(I) FLUORIDE or SILVER MONOFLUORIDE (7775-41-9) AgF AgF HOH Moisture- and light-sensitive, hygroscopic, corrosive solid. Contact with acetylene produces silver acetylide, a shock-sensitive explosive material. Contact with ammonia produces conpounds that are explosive when dry. Contact with hydrogen peroxide causes violent deconposition and release of oxygen gas. Contact with boron, strong oxidizers may cause fire and explosions. Violent reaction when mixed with calcium hydride (fiiction sensitive) dimethyl sulfoxide (DMSO) silicon. Soluble silver compounds attack some forms of plastics, rubber, and coatings. 

CHLORINE FLUORIDE OXIDE (7616-94-6) Noncombustible, but many chemical reactions can cause fire and explosions. A powerful oxidizer. Reacts violently with reducing materials, alcohols, alkalis, amines, anilines, benzene, butyl-amine, calcium hydride, calcium acetylide, charcoal, combustible materials, ethers, hydrazine, hydrogen sulfide, finely divided metals, nitric oxide, olefins, orgtinic substances, potassium cyanide, potassium thiocyanate, sodium, strontium hydride, sulfur, sulfur dichloride, sulfuric acid. Incompatible with hydrogen sulfide, potassium thiocyanate, vinylidene chloride. Forms heat-, friction-, and shock-sensitive explosives with calcium hydride, nitrogenous bases, isopropylamine. Attacks some plastics, rubber, and coatings. 

Drawert at al. [38] employed chemical reactions in the chromatographic determination of water in alcohol solutions and of ethanol in blood. To determine water in alcohol solutions they used a reactor filled with a mixture of Sterchamol and calcium hydride (1 1). The hydrogen formed as a result of the reaction of water with calcium hydride was easily separated from all alcohols on a chromatographic column and detected as a narrow peak. 

A method for the determination of water in hquids, based on GC analysis of the hydrogen evolved during the reaction of water with calcium hydride, was described by Starshovet al. [83],... 

Chromium oxide catalysts on support polymerize isoprene-like butadiene to solid polymers. Here too, however, during the polymerization process, polymer particles cover the catalyst completely within a few hours from the start of the reaction and retard or stop further polymer formation. The polymerization conditions are the same as those used for butadiene. The reactions can be carried out over fixed bed catalysts containing 3% chromium oxide on Si02-Al203. Conditions are 88°C and 42 kg/cm pressure with the charge containing 20% of isoprene and 80% isobutane [122]. The mixed molybdenum-alumina catalyst with calcium hydride also yields polyisoprene. 

Note Z. Dried by stirring the commercial product during some hours with calcium hydride at 40-50 C and subsequently distilling in a water-pump vacuum. HMPT as a cosolvent gives similar results, but the reaction times are much longer. 

Show a mechanism (a sequence of molecular-level events) for the reaction of calcium hydride with water to produce aqueous calcium cations and hydroxide... 

Calcium hydride is highly ionic and is insoluble in all common inert solvents. It can be handled in dry air at low temperatures without difficulty. When heated to about 500°C, it reacts with air to form both calcium oxide and nitride. Calcium hydride reacts vigorously with water in either Hquid or vapor states at room temperature. The reaction with water provides 1.06 Hters of hydrogen per gram CaH2. 

MetaHic potassium and potassium—sodium alloys are made by the reaction of sodium with fused KCl (8,98) or KOH (8,15). Calcium metal and calcium hydride are prepared by the reduction of granular calcium chloride with sodium or sodium and hydrogen, respectively, at temperatures below the fusion point of the resulting salt mixtures (120,121). 

Good yields of phenylarsine [822-65-17, C H As, have been obtained by the reaction of phenylarsenic tetrachloride [29181-03-17, C H AsCl, or phenyldichloroarsine [696-28-6], C3H3ASCI25 with lithium aluminum hydride or lithium borohydride (41). Electrolytic reduction has also been used to convert arsonic acids to primary arsines (42). Another method for preparing primary arsines involves the reaction of arsine with calcium and subsequent addition of an alkyl haUde. Thus methylarsine [593-52-2], CH As, is obtained in 80% yield (43) ... 

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