Cupric chloride, preparation

Addition Chlorination. Chlorination of olefins such as ethylene, by the addition of chlorine, is a commercially important process and can be carried out either as a catalytic vapor- or Hquid-phase process (16). The reaction is influenced by light, the walls of the reactor vessel, and inhibitors such as oxygen, and proceeds by a radical-chain mechanism. Ionic addition mechanisms can be maximized and accelerated by the use of a Lewis acid such as ferric chloride, aluminum chloride, antimony pentachloride, or cupric chloride. A typical commercial process for the preparation of 1,2-dichloroethane is the chlorination of ethylene at 40—50°C in the presence of ferric chloride (17). The introduction of 5% air to the chlorine feed prevents unwanted substitution chlorination of the 1,2-dichloroethane to generate by-product l,l,2-trichloroethane. The addition of chlorine to tetrachloroethylene using photochemical conditions has been investigated (18). This chlorination, which is strongly inhibited by oxygen, probably proceeds by a radical-chain mechanism as shown in equations 9—13. 

Cupric chloride or copper(II) chloride [7447-39 ], CUCI2, is usually prepared by dehydration of the dihydrate at 120°C. The anhydrous product is a dehquescent, monoclinic yellow crystal that forms the blue-green orthohombic, bipyramidal dihydrate in moist air. Both products are available commercially. The dihydrate can be prepared by reaction of copper carbonate, hydroxide, or oxide and hydrochloric acid followed by crystallization. The commercial preparation uses a tower packed with copper. An aqueous solution of copper(II) chloride is circulated through the tower and chlorine gas is sparged into the bottom of the tower to effect oxidation of the copper metal. Hydrochloric acid or hydrogen chloride is used to prevent hydrolysis of the copper(II) (11,12). Copper(II) chloride is very soluble in water and soluble in methanol, ethanol, and acetone. 

Anhydrous cupric chloride was prepared by heating the dihydrate at 110° overnight. 

Another preparatively useful procedure for monohalogenation of ketones involves reaction with cupric chloride or cupric bromide.121... 

In this study, we extend the range of inorganic materials produced from polymeric precursors to include copper composites. Soluble complexes between poly(2-vinylpyridine) (P2VPy) and cupric chloride were prepared in a mixed solvent of 95% methanol 5% water. Pyrolysis of the isolated complexes results in the formation of carbonaceous composites of copper. The decomposition mechanism of the complexes was studied by optical, infrared, x-ray photoelectron and pyrolysis mass spectroscopy as well as thermogravimetric analysis and magnetic susceptibility measurements. 

A bottle of cuprous chloride solution prepared by standing cupric chloride in strong hydrochloric acid over excess copper burst on standing. In the presence of some complexing agents, copper can react with aqueous media to form hydrogen. Slow pressurisation by this means explains the above explosion (Editor s comments). The metal is also known to dissolve in cyanides and some amine solutions. 

Other Methods of Preparation.—Ethyl 2-(D-ara6i no-tetrahydroxybutyl)-5-methyl-4-furoate has been prepared by heating D-glucose plus ethyl acetoacetate in aqueous alcohol without a catalyst,1 or from the same reagents (1 g. and 0.5 ml., respectively) in 0.5 ml. of 96% ethanol plus 1.5 ml. of water at room temperature in the presence of ferric chloride, zinc chloride (with small quantities of hydrochloric acid or of sodium hydroxide), cupric chloride, ferric sulfate, zinc sulfate, aluminum chloride, nickel chloride, or cobalt nitrate.18... 

A similar method can be used for the addition of carbon tetrachloride to nonpolymerizable olefins (e.g., 1-octene, 2-octene, 1-butene, 2-butene) pure adducts are obtained in yields of over 90% if the components are allowed to react at 100° for 6 hours. Adducts of carbon tetrachloride with vinylic monomers (styrene, butadiene, acrylonitrile, methyl acrylate, etc.) can be prepared in good yields by substituting cupric chloride dihydrate in acetonitrile for ferric chloride hexahydrate and benzoin. 

Chlorobenzenesulfonamide can be prepared from -chloroaniline by diazotization and treatment of the resulting diazonium salt with sulfur dioxide and hydrochloric acid in the presence of cuprous or cupric chloride to yield the sulfonyl chloride (Ref. 4) which is converted to the sulfonamide with ammonia. 

As was pointed out in Part A, Section 7.3, under many conditions halogenation is faster than enolization. When this is true, the position of substitution in unsymmetrical ketones is governed by the relative rates of formation of the isomeric enols. In general, mixtures are formed with unsymmetrical ketones. The presence of a halogen substituent decreases the rate of acid-catalyzed enolization and therefore retards the introduction of a second halogen at the same site. Monohalogenation can therefore usually be carried out satisfactorily. A preparatively useful procedure for monohalogenation of ketones involves reaction with cupric chloride or cupric bromide.81 82 83 84 85 86... 

The cuprous chloride solution prepared as described above is more satisfactory and cheaper than one prepared by reducing cupric chloride with copper turnings. 

It is more convenient to prepare cuprous chloride by reducing copper sulfate with sodium bisulfite than by the action of copper upon cupric chloride (see also p. 33). It is well to test a sample of the filtrate with sodium bisulfite solution no further cuprous chloride should separate. 

Hexammino-cupric Chloride, [Cu(NH3)6]Cl2.—This salt was prepared by Faraday in ISIS by allowing ammonia gas to act upon fused cuprie chloride. Increase in bulk immediately took place and a blue powder was formed. The compound may be conveniently prepared by allowing dry ammonia to act on a solution of the cupric salt in ethyl acetate, when a green precipitate of hexammino-chloride is formed which is washed with ethyl acetate and dried.1 The same compound is obtained by the action of liquid ammonia on anhydrous cupric chloride previously saturated with ammonia gas.2... 

Pentammino-cupric Chloride Sesquihydrate, [Cu(NH3)B]Cl2. 1 H20, is prepared by cooling an ammoniacal solution of cupric chloride to —15° C., or by the action of ammonia on the ammoniacal liquid at 0° C. It is a dark blue crystalline substance and decomposes above 0° C., with formation of diammino-cupric chloride. It is soluble in water and in aqueous ammonia, and the crystals remain unaltered in an atmosphere of dry ammonia. If allowed to stand in a desiccator over... 

Application 2.—The second plan of procedure is well illustrated in the preparation of cupric chloride, which is very soluble in water. The cheapest salt of copper is the sulfate, and this may be brought into double... 

As in the case of ferric chloride, cupric chloride is only incompletely reduced by sulphur dioxide in concentrated hydrochloric acid solution, but in aqueous solution this forms an excellent method for the preparation of cuprous chloride ... 

Even the comparatively unreactive phenoxazine and phenothiazine systems undergo halogenation and nitration with ease and it is normal to prepare monosubstituted derivatives by stepwise procedures rather than by direct electrophilic attack. Indeed, the nitration of phenoxazine is uncontrollable and even N-acylphenoxazines afford a mixture of di- and tetra-nitro products (03CB475). Similarly phenothiazine and nitric acid produce a complex mixture of nitrated sulfoxides and sulfones. Chlorine in DMSO at 40 °C reacts with phenothiazine to yield 3,7-dichlorophenothiazine, whereas cupric chloride gives the 1,7-isomer (76JPR353). Direct bromination of phenoxazine produces a mixture of 3-bromo- and 3,7-dibromo-phenoxazines, while thionyl chloride affords the 1,3,7,9-tetrachloro derivative (60ZOB1893). 

The purity of the gas is tested by explosion analysis (J. C. S., 84, 555) the ratio, contraction on explosion to absorption by baryta water after explosion, should lie between 0-73 and 0-77 (theoretical 0,75). Great care must be taken that this preparation is carried out in the absence of flame, and that neither the apparatus nor the collected gas is exposed to direct sunlight, which decomposes acetylene. Also the cupric chloride solution employed for washing should be kept acid if it becomes alkaline the explosive copper aeetylide is precipitated. Should this occur the solution is mixed with much water and poured away. 

Di(3-benzo[6]thienyl)methane is obtained by treatment of 3-benzo-[6]thienylmagnesium bromide with 3-chloromethylbenzo [ thiophene.486 Two molecules of 3-benzo[6]thienylmagnesium iodide may be coupled by treatment with cupric chloride,305 but not with cupric bromide or nickel bromide,349 to yield 3,3 -di(benzo[6]thienyl). A claim349 to have prepared the same compound by the Ullmann reaction is probably not justified.305 The Ullmann reaction otherwise seems to be of general application in the benzo [6]thiophene series.87-483 Halobenzo[6]thiophenes76 105 511 can be selectively metallated in the 2-position by the use of w-butyllithium (Section VII). 

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