Wurtz Reaction

The Wurtz reaction is an organic chemical process that is applied in laboratories to create alkanes. In the presence of dry ether, it is a coupling reaction between two haloalkanes and the use sodium metal. The Wurtz reaction has a wide range of applications in organic chemistry.

Wurtz Reaction

The Wurtz reaction is named after Charles Adolphe Wurtz, a French chemist. He discovered the Aldol reaction and provided the mechanism for the Wurtz reaction. Two alkyl halides (Haloalkanes) combine with sodium metal in the presence of dry ether to form higher alkanes in the Wurtz reaction. Other elements, such as activated copper, zinc, iron, silicon, or indium, can be used in place of sodium metal.

R-X+2Na+X-R` R-R`+2NaX 

Eg:

C2H5Cl+2Na+Cl-2Na     dry ether C4H10n-butane+2NaCl 

Wurtz reactions are only possible in a dry environment. Because sodium reacts violently with oxygen and moisture, an anhydrous state is required.

Na+H2O→NaOH+H2

Because of its high reactivity, sodium cannot be stored in a normal environment, hence it is stored in kerosene. Tetrahydrofuran can be used instead of anhydrous ether. To make alkanes, an alkyl free radical with unpaired electrons in the outer shell is used. Alkene is produced as a by-product of free radical action.

Wurtz Fittig Reaction

The Wurtz Fittig Reaction is a Wurtz reaction in which aryl halides are utilised instead of alkyl halides.

WURTZ REACTION EQUATION:

The general form of the wurtz reaction equation can be written as follows

2R-X + 2Na → R-R + 2Na++X-

The two R groups are combined to generate an alkane with a longer chain, as well as NaX, where X is a Halogen, as shown in this equation.

Example of Wurtz Reaction

Wurtz reactions are used to produce ethane from methyl chloride. Ethane and sodium chloride are generated when methyl chloride interacts with sodium metal in the presence of dry ether.

2CH3Cl + 2Na → CH3-CH3  + 2NaCl

For more example

RX+2Na+RX R-R+2NaX

CH3Cl+2Na+ClCH3   pure and dry ether   CH3CH3+2NaCl

CH3Cl+2Na+ClC2H5     Pure and dry ether   mixture of R`-R`+R`-R+R-R(mixture of three)

Mechanism of Wurtz Reaction

The general equation of Wurtz reaction is given below:

2R-X+2Na→R-R+2Na+X-

The alkyl group is represented by R, and the halogen is represented by X. The creation of higher alkane from alkyl halide is well depicted in the equation.

The Wurtz reaction mechanism involves a free radical species denoted by R• which is a part of a halogen-metal exchange. Grignard reagents have a mechanism that is comparable to this one. A nucleophilic substitution reaction forms the carbon-carbon bond, which can be broken down into three steps:

Step 1: The halogen receives an electron from the sodium metal. Alkyl free radicals are formed as a result of this.

R-X+Na→R• +Na+X-

Step 2: The nucleophilic alkyl free radical combines with sodium metal. The result is the formation of an alkyl anion.

R• + Na → R-Na+

Step 3: An alkyl anion with a lot of electrons reacts with another alkyl halide to generate an alkane. A bond is broken and a new bond is produced in this SN2 reaction.

R-Na++ R-X → R-R + Na+X-

As a result of the Wurtz reaction process, the necessary alkane product is generated. Due to the creation of numerous products, the reaction yields are low.

Wurtz Reaction Application

A.In the laboratory, the Wurtz–Fittig reaction is effective for synthesising organosilicon compounds. The Wurtz–Fittig reaction, for example, can be used to make t-butyl trimethoxysilane. In this case, a 40% yield is achieved.

B.Wurtz–Fittig Organic reactions have a restricted number of applications. It isn’t employed on a wide scale in the industrial sector. It is, nonetheless, useful in the synthesis of substituted aromatic compounds in the laboratory.

C.There aren’t many uses for this reaction. This is due to the side reaction, which undergoes additional reorganisation and elimination. This is one of the reaction’s key drawbacks, making it unsuitable for many manufacturing operations.

D.This reaction is used to make organosilicon, albeit it is a significant problem to achieve large-scale manufacturing.

This was the case.

Limitation of Wurtz Reaction

When R and R are the same, that is, when the alkane has an even number of carbon atoms and is symmetrical, the best yield is attained. The Wurtz reaction produces good yields only for carbon alkanes with a high molecular mass, according to experiments. With tertiary alkyl halides, it fails.

Conclusion

The Wurtz reaction is an organic chemical process that is applied in laboratories to create alkanes. In the presence of dry ether, it is a coupling reaction between two haloalkanes and the sodium metal. we have discussed about Wurtz reaction, wurtz reaction equation, examples of wurtz reaction, limitations and applications. At last we will discuss about some important question related to wurtz reaction.