Carbon tetrachlorid

CARBON TETRACHLORIDE CARBON TETRACHLORIDE CARBON TETRACH.OR lOE CYCLOHEXANE CYCLOHEXANE CYCLOHEXANE CYCLOHEXANE CYCLOHEXANE 1 2-OlCHLOROETHANE I,2-DICHLORDETHANE 1 (2-DtCHLOROETHANE OI-ETHYL ETHER DI-ETHYL ETHER DI-ETHVL ETHER 01-ETHYL ETHER OI-ETHYL ETHER OI-ETHYL ETHER ETHYL ACETATE ETHYL ACETATE... 

Andrews deration An important titration for the estimation of reducing agents. The reducing agent is dissolved In concentrated hydrochloric acid and titrated with potassium iodale(V) solution. A drop of carbon tetrachloride is added to the solution and the end point is indicated by the disappearance of the iodine colour from this layer. The reducing agent is oxidized and the iodate reduced to ICl, i.e. a 4-eiectron change. 

C. Manufactured by the action of HF on CCI4 using SbClj as a catalyst. Known commercially as Freon-12 or Arcton-12. Widely used as a refrigerant and aerosol propellant. It is much less toxic than carbon tetrachloride. 

CH2CI2. A colourless liquid with a chloroform-like odour b.p. 4I°C. Prepared by heating chloroform with zinc, alcohol and hydrochloric acid manufactured by the direct chlorination of methane. Decomposed by water at 200°C to give methanoic and hydrochloric acids. Largely used as a solvent for polar and non-polar substances, particularly for paint removal (30%), dissolving cellulose acetate and degreasing (10%). It is more stable than carbon tetrachloride or chloroform especially towards moisture or alkali. It is somewhat toxic. U.S. production 1981 280000 tonnes. 

This measurement provides a definition of the bitumen content in bitumen materials as the portion soluble in carbon disulfide (in France, in trichloroethylene, carbon tetrachloride or tetrachloroethylene). The method is defined by AFNOR NF T 66-012 or IP 47, or ASTM D 4 (the latter is not equivalent to the others). 

The ability to act as a lone pair acceptor is not confined to Group III, and can occur wherever a quantum level is incomplete. This ability to accept electrons explains why covalent chlorides, with the exception of carbon tetrachloride, are readily hydrolysed, the apparently anomalous behaviour of carbon tetrachloride being readily explained by the fact that the carbon has a completed quantum level and is unable to form an intermediate complex with water. 

The unequal distribution of charge produced when elements of different electronegativities combine causes a polarity of the covalent bond joining them and, unless this polarity is balanced by an equal and opposite polarity, the molecule will be a dipole and have a dipole moment (for example, a hydrogen halide). Carbon tetrachloride is one of a relatively few examples in which a strong polarity does not result in a molecular dipole. It has a tetrahedral configuration... 

Hydrogen fluoride also effects replacement reactions in organic compounds. For example, carbon tetrachloride yields a mixture of chlorofluoromethanes CCI3F, CCI2F2 and so on. Like all the other hydrogen halides, hydrogen fluoride adds on to olefins, for example ... 

Dibromine monoxide, BtjO, is prepared, similar to the corresponding dichlorine compound, by the action of a solution of bromine in carbon tetrachloride on yellow mercury(II) oxide ... 

Most covalent halides are hydrolysed by water (carbon tetrachloride being a notable exception, p. 195) to give acidic solutions, by either method (a) (example FeClj) or method (b) (example BCI3) ... 

Addition of an oxidising agent to a solution of an iodide (for example concentrated sulphuric acid, hydrogen peroxide, potassium dichromate) yields iodine the iodine can be recognised by extracting the solution with carbon tetrachloride which gives a purple solution of iodine. 

Calculations of relative partition coefficients have been reported using the free energy perturbation method with the molecular dynamics and Monte Carlo simulation methods. For example, Essex, Reynolds and Richards calculated the difference in partition coefficients of methanol and ethanol partitioned between water and carbon tetrachloride with molecular dynamics sampling [Essex et al. 1989]. The results agreed remarkably well with experiment... 

The bromine test is applied first. The organic compound, if a liquid, is treated with 2-3 drops of liquid bromine or (preferably) a solution of bromine in carbon tetrachloride if the organic compound is a solid, it should first be dissolved in cold carbon tetrachloride or chloroform. The rapid absorption of the bromine (and consequent disappearance of the red colour) is a strong indication that the compound is unsaturated, and is therefore undergoing direct addition of the bromine. 

Pour the mixture into a separating-funnel. Owing to the density of the acetate being only slightly greater than that of water, a sharp separation is usually not rapidly obtained. It is advisable therefore to add about 8 ml. of carbon tetrachloride, when, after shaking, a sharp and rapid separation of the heavy solution of the phenyl acetate in the... 

The substitution is best carried out by boiling A -bromosuccinimide with the olefine in carbon tetrachloride. Succinimide crystallises out from the carbon tetrachloride on cooling w hereas the brominated product remains dissolved in the carbon tetrachloride. 

Required Ethyl crotonate, 22-8 g. V-bromosuccinimide, 35 6 g. carbon tetrachloride, 40 ml. 

Dissolve 22-8 g. of ethyl crotonate in 40 ml. of dry carbon tetrachloride and add 35 6 g. of. V-bromosuccinimide. Heat the mixture under reflux for three hours. Cool to o and filter off the succinimide which is insoluble in cold carbon tetrachloride. Now shake the filtrate with water in a separating funnel, separate and dry the carbon tetrachloride layer with sodium sulphate. Filter through a fluted filter-paper into a Claisen flask and distil... 

A) Extract the mixture with about 40 ml. of chloroform, in which the free base is very soluble. Run off the lower chloroform layer, dry it with potassium carbonate as in (a), and then add carbon tetrachloride slowly with stirring to the filtered chloroform solution until the base starts to crystallise out. Allow to stand for a short time (t.e., until the deposition of crystals ceases) and then filter at the pump as the crystals lose the last trace of solvent, they tend as before to break up into a fine powder, the deep green colour becoming paler in consequence. 

Aminoazobenzene is freely soluble in methylated spirit, although insoluble in water. For recrystallisation, therefore, dissolve the crude substance in boiling methylated spirit, remove from the water-bath, and then add water drop by drop until the solution becomes just cloudy owing to the separation of the solute replace the solution momentarily on the water-bath until the cloudiness disappears, and then at once remove the solution, and allow it to cool slowly. (Alternatively, the crude dry material can be reciystallised from carbon tetrachloride in the usual way.) Aminoazobenzene is thus obtained as yellowish-brown crystals, m.p. 126° yield, 5 g. 

Cinnamic acid can be readily esterified by the Fischer-Speier method without any risk of the addition of hydrogen chloride at the double bond. Proceed precisely as for the preparation of ethyl benzoate (p. 104), using 20 g. of cinnamic acid and 20 ml. of rectified spirit. When the crude product is poured into water, a sharp separation of the ester is not readily obtained, and hence the addition of about 10 ml. of carbon tetrachloride is particularly desirable. Finally distil off the carbon... 

Methyl iodide, ethyl bromide and iodide, higher alpihatic halides chloroform, iodoform, carbon tetrachloride chlorobenzene, bromobenzene, iodobenzene benzyl chloride. 

Aniline.—Burns with a very smoky flame, clouds of soot being produced. Typical of many aromatic substances. i,2 Dibromoethane.—Does not burn until vapour becomes hot and then burns with a slightly smoky flame. Typical of substances rich in halogens such as cldoroform, chloral hydrate, and carbon, tetrachloride. (Note, however, that iodoform evolves copious fumes of iodine when heated in this way.)... 

Physical Properties. All heavier than, and insoluble in water. All liquids, except iodoform, CHI3, which is a yellow crystalline solid with a characteristic odour. The remainder are colourless liquids when pure ethyl iodide, CjHjI, and iodobenzene, CjHgl, are, however, usually yellow or even brown in colour. Methyl iodide, CH3I, ethyl bromide, CgH Br, ethyl iodide, chloroform, CHCI3, and carbon tetrachloride, CCI4, have sweetish odours, that of chloroform being particularly characteristic. 

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