Chlorinated Butane Derivatives

Compound B.P., C., corr. Press.. mm. Density d Refractive Index. Chlorine. Found Calcd. 

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By-products resulting from the chain-termination steps would be butane and any chlorination products derived from it. 

Methane ethane and cyclobutane share the common feature that each one can give only a single monochloro derivative All the hydrogens of cyclobutane for example are equivalent and substitution of any one gives the same product as substitution of any other Chlorination of alkanes m which the hydrogens are not all equivalent is more com plicated m that a mixture of every possible monochloro derivative is formed as the chlo rmation of butane illustrates... 

In the presence of catalysts, trichloroethylene is readily chlorinated to pentachloro- and hexachloroethane. Bromination yields l,2-dibromo-l,l,2-trichloroethane [13749-38-7]. The analogous iodine derivative has not been reported. Fluorination with hydrogen fluoride in the presence of antimony trifluoride produces 2-chloro-l,l,l-trifluoroethane [75-88-7] (8). Elemental fluorine gives a mixture of chlorofluoro derivatives of ethane, ethylene, and butane. 

Only two alkanes have the molecular formula C4H10 butane and isobutane (2-methylpropane)— both of which give two monochlorides on free-radical chlorination. However, dehydrochlorination of one of the monochlorides derived from butane yields a mixture of alkenes. 

All this was later put on a sound basis as a result of more precise measurements of rate constants and of activation energies. However, it did not require precise measurements to predict which chlorinated hydrocarbons would decompose by a radical chain mechanism and which by the unimolecular mechanism. Clearly, if the chlorinated hydrocarbon, or the product from the pyrolysis of the chlorinated hydrocarbon reacted with chlorine atoms to break the chain then the chain mechanism would not exist. Such chlorinated hydrocarbons would decompose by the unimolecular mechanism. Mono-chlorinated derivatives of propane, butane, cyclohexane, etc. would afford propylene, butenes, cyclohexene, etc. All these olefins are inhibitors of chlorine radical chain reactions because of the attack of chlorine atoms at their allylic positions to give the corresponding stabilized allylic radicals which do not carry the chain. 

USE In the manuf of chlorinated derivs as refrigerant in some two-stage refrigeration systems where relatively low temps are produced as fuel gas (so called "bottled gas" or suburban propane" contains about 90% propene, 5% ethane, and 5% butane). Caution. Narcotic in high concns. A simple asphyxiant. 

Phenylhydrazones derived from 2-oxopropionaldehyde, benzoylformaldehyde, and butane-2,3-dione led to dinuc-lear metallacycles. " The addition of NaOMe in MeOH afforded deep violet eompounds which do not contain chlorine atoms. Deprotonation takes place by means of a hydrazo-keto azo-enol tautomerization involving 92 and 93 (Scheme 17). 

This disconnection suggests that in the synthetic direction, the OH group of oxime TM 7.2d approaches the cyano group, completing the cyclization. Presentation of both functional groups as acyclic cyano-oxime suggests interconversion to 3-cyanobutan-2-one and then to 3-chlorobutan-2-one, easily available by chlorination of butan-2-one. Acetanilide is an available commodity used in the production of para-chlorosulfonyl derivative TM 7.2c. 

The chlorination of higher-molecular-weight alkanes yields a mixture of isomeric monochlorinated products. For example, the chlorination of butane or 2-methyl-propane, which have nonequivalent hydrogen atoms, yields significant amounts of isomeric monochlorinated derivatives. 

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