Calcium carbide, formation

Methods of EGA using selective sorption, condensation of effluent gases, infrared absorption and thermoparticulate analysis have been reviewed by Lodding [144]. The use of simple gas burette systems should not be forgotten and an Orsat gas analysis apparatus can provide useful measurements in studies of the decomposition of formates [169]. Problems have been encountered in the determination of water released Kiss et al. [170—172] have measured the formation of this compound from infrared analyses of the acetylene evolved following reaction of water with calcium carbide. Kinetic data may be obtained by wet methods ammonia, determined by titration after absorption in an aqueous solution, has been used to measure a—time values for the decomposition of ammonium salts in a fluidized bed [173],... 

Several other processes for extracting Be from beryl have been patented the most feasible involves the formation of BeCl2 by direct chlorination of beryl under reducing conditions several volatile chlorides are produced by this reaction (BeCl2, AICI3, SiCl4 and FeClj) and are separated by fractional condensation to give the product in a pure state. Other methods involve the fusion of beryl with carbon and pyrites, with calcium carbide and with silicon. 

These give rise to the same dangerous reactions as chromium halides. Iron dichloride and trichloride detonate in contact with sodium or potassium. There is also a violent combustion of an iron trichloride/calcium carbide mixture, which leads to the formation of melted iron. 

Thus, all copper salts give an explosive reaction with calcium carbide. This is due to the formation of explosive copper acetylide, which is formed from cupric or cuprous cation and the acetylene formed. 

At 305°C, iodine mixed with calcium carbide produces incandescence in the mixture. Can it be explained by the formation of diodoacetylene followed by its decomposition ... 

Calcium carbide, 32, 70 Calcium carbonate, 32, 81 Calcium formate, 31,102 CAPROIC ACID, e-AMINO, 32, 13 e-Caprolactam, 31, 72 32, 15 e-CAPROLACTIM, O-METHYL-, 31, 72 CAPRONITRILE, a-ETHYL, 32, 6S Caproyl chloride, 31, 71 CARBANILINONITRILE, O-CHLORO, 31, 19... 

Catalytic forms of copper, mercury and silver acetylides, supported on alumina, carbon or silica and used for polymerisation of alkanes, are relatively stable [3], In contact with acetylene, silver and mercury salts will also give explosive acetylides, the mercury derivatives being complex [4], Many of the metal acetylides react violently with oxidants. Impact sensitivities of the dry copper derivatives of acetylene, buten-3-yne and l,3-hexadien-5-yne were determined as 2.4, 2.4 and 4.0 kg m, respectively. The copper derivative of a polyacetylene mixture generated by low-temperature polymerisation of acetylene detonated under 1.2 kg m impact. Sensitivities were much lower for the moist compounds [5], Explosive copper and silver derivatives give non-explosive complexes with trimethyl-, tributyl- or triphenyl-phosphine [6], Formation of silver acetylide on silver-containing solders needs higher acetylene and ammonia concentrations than for formation of copper acetylide. Acetylides are always formed on brass and copper or on silver-containing solders in an atmosphere of acetylene derived from calcium carbide (and which contains traces of phosphine). Silver acetylide is a more efficient explosion initiator than copper acetylide [7],... 

Eor inert SAMs such as n-aUcanethiolates/Au, alkaline earth and alkali metal deposition on inert SAMs tends to exhibit low sticking coefficients of the nascent metal atoms due to quite weak interactions with the -CH3 terminus sometimes <10 of the impinging metal atoms stick to the surface while the rest scatter off the smface [23, 58]. Bammel and co-workers observed quite slow penetration of Na through this inert SAM [59]. In the case of Mg and Ca depositions on n-aUcanethiolate SAMs it was observed that while Mg does not react it does undergo continuous penetration thorough the SAM. In contrast, Ca does react to some extent resulting in calcium carbide species formation [56, 57]. In the case of K on an n-aUcanethiolate SAM the results are more complicated. For example, at 10 K atoms per SAM molecule, it has been reported that half of the deposited metal penetrates to the SAM/Au interface while the remainder is claimed to remain embedded within the SAM matrix [60], though such space is not available theoretically in a dense SAM. 

Calcium carbide for acetylene is mainly packed in returnable steel bulk containers ranging in capacity from 2.5—4.5 t, suitable for lift trucks and unloading conveyors. The granular carbide is lightly oiled with alubricating oil (see Lubrication and lubricants), which decreases the rate of reaction when exposed to moist air and also reduces dust formation during handling. 

Calcium carbide CaC2 exists in at least four crystalline modifications whose occurrence depends on the temperature of formation and the presence of impurities. The tetragonal phase CaC2(I), which is stable between 298 and 720 K, is... 

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... 

Methane from Carbides.—Another method of preparation is of interest and importance because of its connection with theories as to the formation of methane and other hydrocarbons in petroleum. With some metals carbon forms compounds which are very stable at high temperatures, and which have been artificially produced in the electric furnace (about 35O0°C.) by Moissan. These metallic carbon compounds, known as carbides, are, most of them, easily decomposed by water at ordinary temperatures, and when so decomposed they yield various members of the hydrocarbon group of compounds. A familiar example of this class of reactions is the one by which acetylene gas is made by the action of water on calcium carbide. The carbide of aluminium decomposes with water and yields methane according to the foUowing reaction ... 

Desulfurization of hot iron by addition of calcium carbide leads to formation of a slag containing calcium sulfide and hydroxide as well as substantial amount of iron oxides. This slag is completely different than other metalurgical slags and may be effectively used for treatment of various acidic dr neutral wastewater containing heavy metal cations by hydroxide/sulfide precipitation, and, by removal of several components from wastewater by sorption and other interactions with iron oxides. 

Introduction. Acetylene has the empirical formula C2Hs. It shows a greater unsaturation than ethylene, in that it can add four univalent groups to each carbon atom. This xmsaturation is indicated by a triple bond between the two carbon atoms HC=CH. Acetylene is produced in the thermal decomposition of many hydrocarbons. Of theoretical interest is its formation from hydrogen and carbon in the electric arc. It is prepared industrially by the pyrolysis of methane, and by the action of water on calcium carbide. The last method is employed for preparation of small quantities in the laboratory ... 

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