Propene reaction with chlorine

However, when propene reacts with chlorine or bromine at very high temperatures or under conditions in which the concentration of the halogen is very small, the reaction that occurs is a substitution. These two examples illustrate how we can often change the course of an organic reaction simply by changing the conditions. (They also illustrate the need for specifying the conditions of a reaction carefully when we report experimental results.)... 

The propene is finally treated with chlorine solution and it undergoes an addition reaction to form the desired product, 1,2-dichloropropane. 

The reaction of chlorine with propene illustrates one difference caused by conjugation. The products of the reaction depend upon the reaction conditions, as illustrated in Figure 4-6. 

Incidentally, this reaction of chlorine with propene is also chemoselective. 

PROPENE or 1-PROPENE (115-07-1) Flammable gas (flash point - 162°F/-108°C). Able to form unstable peroxides that may cause polymerization. Violent reaction with strong oxidizers, trifluoromethyl hypofluorite, fluoride, chlorine, and many other compounds. Incompatible with ammonium hydroxide. Forms explosive materials with nitrogen oxide compounds. May accumulate static electrical charges, and may cause ignition of its vapors. 

A typical reaction involving nickel(O) treats an allylic halide such as 3-chloro-2-methyl-l-propene with Ni(CO)4 to form 439,288 a nickel dimer analogous to the palladium chloride dimer discussed in the previous section. This complex reacts with an alkene to form a new complex (440), and subsequent reaction with a variety of electrophilic reagents removes nickel. In this example, the chlorine was converted to an acetate ligand (in 441) and reacted with methanolic carbon monoxide to give the ester (442).288... 

Allylic hydrogens are especially reactive in radical substitution reactions. We can synthesize allylic halides by substitution of allylic hydrogens. For example, when propene reacts with bromine or chlorine at high temperatures or under radical conditions where the concentration of the halogen is small, the result is allylic substitution. 

Chlorine is very much utilized in the synthesis of organic chemicals. If one or more hydrogen atoms are substituted with chlorine in molecules like ethene, propene, benzene and toluene, it will be possible to accomplish syntheses that are not possible with the original molecules with their low reactivity. The final products, such as for instance silicones, polyurethanes and polycarbonates, contain no chlorine, as the substituted element reacts to chlorides of hydrogen or sodium and leaves the reaction. However, important syntheses are also performed, in which chlorine stays in the product. Polyvinyl chloride (PVC) is an example. 

Notice that the addition of chlorine converts the carbon-carbon double bond into a single bond because each carbon atom now has formed a new bond with a chlorine atom. Alkenes and alkynes can also add hydrogen in hydrogenation reactions. For example, in the presence of an appropriate catalyst, propene reacts with hydrogen gas to form propane. 

Scheme 2.1.2 Reactivity of radicals, carbocations, and carbanions exemplified for reactions of relevance in chemical technology reaction of (a) the methyl radical with chlorine key-step in methane chlorination) (b) the isopropylium ion with water (key-step in isopropanol synthesis from propene) ...

When propene reacts with bromine or chlorine at low temperatures, the reaction that takes place is the usual addition of halogen to the double bond ... 

Chloro-2-methyl-l-propene,methallyl chloride, CH2=C(CH3)-CH2C1, is produced by the chlorination of isobutylene in the gas phase at temperatures below 100 C. Of greatest commercial interest are its reactions with sodium sulfite to give sodium methallyl sulfonate, and the production of 2-methyl epichlorohydrin. 

The final isolated product, after the aqueous work-up procedure, was 2-hydroxypropanesulfonic acid 10. Many industrial studies used chlorosulfonic acid in diethyl ether the complex is prepared by dropwise addition of chlorosulfonic acid to diethyl ether at 0 °C. Under these conditions, the initial product of the reaction of propene 8 with chlorosulfonic acid in diethyl ether is probably the chlorinated sulfonic acid 11. The chlorine atom in this compound is very reactive and consequently the isolated products are generally the alkenesul-fonic acid 12 or the hydroxysulfonic acid 10 (Scheme 2) ... 

The kinetics of the reaction of chlorine atoms with 2-methyl-2-propen-l-ol have been studied using a relative rate technique by Rodriguez et al. (2008). The rate coefficient values obtained are presented in table ll-D-21. The authors have reported... 

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