Calcium carbide chloride

Bromine, elemental Calcium carbide, chloride, and hypochlorite... 

Calcium carbide Moisture, selenium, silver nitrate, sodium peroxide, tin(II) chloride, potassium hydroxide plus chlorine, HCl gas, magnesium... 

Calcium carbide has been used in steel production to lower sulfur emissions when coke with high sulfur content is used. The principal use of carbide remains hydrolysis for acetylene (C2H2) production. Acetylene is widely used as a welding gas, and is also a versatile intermediate for the synthesis of many organic chemicals. Approximately 450,000 t of acetylene were used aimuaHy in the early 1960s for the production of such chemicals as acrylonitrile, acrylates, chlorinated solvents, chloroprene, vinyl acetate, and vinyl chloride. Since then, petroleum-derived olefins have replaced acetylene in these uses. 

The chloride is also reduced by calcium carbide at 800—1200°C under vacuum (52). 

A number of high temperature processes for the production of titanium carbide from ores have been reported (28,29). The aim is to manufacture a titanium carbide that can subsequently be chlorinated to yield titanium tetrachloride. In one process, a titanium-bearing ore is mixed with an alkah-metal chloride and carbonaceous material and heated to 2000°C to yield, ultimately, a highly pure TiC (28). Production of titanium carbide from ores, eg, ilmenite [12168-52-4], EeTiO, and perovskite [12194-71 -7], CaTiO, has been described (30). A mixture of perovskite and carbon was heated in an arc furnace at ca 2100°C, ground, and then leached with water to decompose the calcium carbide to acetjdene. The TiC was then separated from the aqueous slurry by elutriation. Approximately 72% of the titanium was recovered as the purified product. In the case of ilmenite, it was necessary to reduce the ilmenite carbothermaHy in the presence of lime at ca 1260°C. Molten iron was separated and the remaining CaTiO was then processed as perovskite. 

Coatiauous kilns were first used ia Germany at Knapsack (20) and later at Trostberg (21). In the Knapsack process, calcium carbide (0.75—2 mm ia size) is fed to a rotary kiln, 3 m ia diameter and 12 m long with 1% slope 1—2% calcium chloride is added to promote the reaction. The kiln produces 12—13 t fixed nitrogen per day. The product is granular and can be sold without further processiag. 

Reaction of coke with calcium oxide gives calcium carbide, which on treatment with water produces acetylene. This was for many years an important starting point for the production of acrylonitrile, vinyl chloride, vinyl acetate and other vinyl monomers. Furthermore, during World War II, Reppe developed routes for many other monomers although these were not viable under normal economic conditions. 

For many years a major route to the production of vinyl chloride was the addition of hydrochloric acid to acetylene (Figure 12.5). The acetylene is usually prepared by addition of water to calcium carbide, which itself is prepared by heating together coke and lime. To remove impurities such as water, arsine and phosphine the acetylene may be compressed to 15 Ibf/in (approx. 100 kPa), passed through a scrubbing tower and chilled to -10°C to remove some of the water present and then scrubbed with concentrated sulphuric acid. 

Normal Fischer esterification of tertiary alcohols is unsatisfactory because the acid catalyst required causes dehydration or rearrangement of the tertiary substrate. Moreover, reactions with acid chlorides or anhydrides are also of limited value for similar reasons. However, treatment of acetic anhydride with calcium carbide (or calcium hydride) followed by addition of the dry tertiary alcohol gives the desired acetate in good yield. 

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. 

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... 

Metal acetylides or carbides Calcium carbide 3.97/46 See Caesium acetylide Mineral acids Rubidium acetylide Acids Uranium dicarbide Hydrogen chloride... 

See also Acetoacetyl-CoA in citric acid cycle, 6 633 Acetyl cyclohexanesulfonyl peroxide (ACSP), 74 282 78 478 Acetylene(s), 7 177-227, 227-228 25 633 addition of hydrogen chloride to, 73 821 from calcium carbide, 4 532, 548 carbometalation of, 25 117 as catalyst poison, 5 257t chemicals derived from, 7 227-265 decomposition of, 70 614 Diels-Alder adduct from cyclopentadiene, 8 222t direct polymerization, 7 514 economic aspects of, 7 216-217 explosive behavior of, 7 181-187 as fuel, 7 221-222 health and safety factors related to, 7 219... 

Aluminum phosphide Amyl trichlorosilane Benzoyl chloride Boron tribromide Boron trifluoride Boron trifluoride etherate Bromine pentafluoride Bromine trifluoride n-Butyl isocyanate Butyllithium Butyric anhydride Calcium Calcium carbide Chlorine trifluoride Chloro silanes Chlorosulfonic acid Chromium oxychloride Cyanamide Decaborane Diborane... 

Mercuric oxide (5 g.) is dissolved for the most part in a still warm mixture of 110 c.c. of water and 50 c.c. of concentrated sulphuric acid. The mixture is brought into a large hydrogenation flask (Fig. 58, p. 377) and shaken for some time with acetylene prepared from calcium carbide, purified with acid solutions of dichromate and copper nitrate, and collected over saturated sodium chloride solution in a glass gas-holder (capacity 10-15 litres). Before shaking is begun the air present must be displaced by the hydrocarbon. 

Thermal reduction processes are not being practiced anywhere in the world at present for large-scale production of sodium. Such methods, however, can he conveniently adapted for laboratory preparation of metalhc sodium. Sodium can be prepared by thermal reduction of its hydroxide, carbonate, or chloride at elevated temperatures. These salts are heated with carbon, calcium carbide, iron carbide, ferrosilicon, or other reducing agents at temperatures above 800°C under vacuum ... 

Calcium Arsenate Calcium Biphosphate Calcium Carbide Calcium Chlorate Calcium Chloride Calcium Chloride Hydrates Calcium Chloride, Anhydrous Calcium Chromate Calcium Chromate Dihydrate Calcium Chromate (VI)... 

Calcium Arsenate Calcium Phosphate Calcium Carbide Calcium Chlorate Calcium Chloride Calcium Chloride Calcium Chloride Calcium Chromate Calcium Chromate Calcium Chromate Calcium Cyanide Calcium Peroxide Calcium Fluoride Calcium Hydroxide Calcium Hypochlorite Calcium Phosphate Calcium, Metallic Calcium Nitrate Calcium Nitrate Calcium Oxide Calcium Peroxide Calcium Phosphate Calcium Phosphate Calcium Phosphide Calcium Resinate Calcium Resinate Calcium Resinate Calcium Phosphate Mercuric Chloride Mercurous Chloride... 

Acetylene is usually thought of as a coke-derived product via calcium carbide. But acetylene, used for vinyl resins manufacture, has been made by partial oxidation of natural gas methane for over a year now in a major installation in Texas, which is now being expanded (6). Moreover, another Gulf Coast plant now under construction will also produce acetylene from natural gas, utilizing this product for acrylonitrile as well as vinyl chloride production (28). These moves represent a momentous advance, pointing to the future entry of natural gas to an even greater degree into aliphatic syntheses. 

A competing process produces vinyl chloride from acetylene, which also can be derived from petroleum feed stocks but is usually made from calcium carbide. It has been estimated (17) that 45% of current production of vinyl chloride is from ethylene, the remainder from acetylene. 

Similar proposals have been made to treat the enormous quantities of calcium chloride obtained as a by-product in many industries either to obtain chlorine (q.v.) or hydrogen chloride. J. T. Pelouze 14 showed that when calcium chloride is mixed with sand to prevent fusion, it is readily decomposed by steam at a red heat with the copious evolution of hydrogen chloride, and the reaction was the basis of the E. Solvay patents in which the calcium chloride was mixed with sand or clay. W. Bramley mixed the calcium chloride with iron ore before heating it in a stream of air for chlorine, or with-steam for hydrogen chloride. W. H. Seamon proposed to treat molten calcium chloride with acetylene to produce calcium carbide and hydrogen chloride. 

According to H. Rose,47 dry powdered ammonium chloride at 0° absorbs the vapour of sulphur trioxide without decomposition, forming a hard mass which, when heated, first develops hydrogen chloride, and forms ammonium sulphate— it has been suggested that the product may be ammonium chloropyro-sulphate, NH4.0.S205C1. With carbon monoxide at a red heat, C. Stammer observed no changes, but with calcium carbide, R. Salvadori obtained calcium chloride, nitrogen, ammonia, carbon, and a series of hydrocarbons—methane, ethylene, and acetylene. 

Assemble an apparatus for preparing acetylene (see Fig. 54). Put about 5 g of calcium carbide into 25-ml round-bottomed flask 1. Fill dropping funnel 2 and cylinder 3 with a 25% sodium chloride solution. Pour a little of a 1-2% sodium hydroxide solution into wash bottle 4, and a 2% potassium dichromate solution acidified with a dilute sulphuric acid solution into test tube 5. By adding the sodium chloride solution in small portions to the calcium carbide, achieve a uniform stream of gas. When the apparatus is filled with pure acetylene, test the gas for the absence of air in it. How can this be done ... 

The cyanamide process has made cyanamide and its derivatives more easily available for commercial synthesis. Coke and limestone are heated together in the electric furnace for the production of calcium carbide. This substance, along with a small amount of calcium chloride which acts as a catalyst, is then heated at 800-1000° in a stream of nitrogen gas. 

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