Difference Between Markovnikov Rule and Anti Markovnikov Rule

The main difference between Markovnikov’s rule and Markovnikov’s rule is that Markovnikov’s rule specifies that hydrogen atoms present in an addition reaction implies having many hydrogen substituents with one carbon atom, while Anti Markovnikov’s rule specifies that hydrogen atoms present in an addition reaction are involved by having minimal hydrogen substituents with a carbon atom.

Markovnikov Rule vs. Anti Markovnikov Rule

Markovnikov’s rule generally explains that when the protic acid of an alkene is added, the H is attached to double bonds with a more significant number of substituted hydrogen atoms attached to the carbon atom. In contrast, the anti-markovnikov rule explains when HBr is added to the alkene in the peroxide appearance of the catalyst, the C-bonded H atom containing less substituted H, while the C-bonded Br has more H. hydrogen will always bond to that carbon atom. having the maximum number of hydrogen substituents attached to the carbon atom according to Markovnikov’s rule; conversely, the hydrogen atom will always bond to the carbon atom that has the least number of hydrogen substituents according to the anti-Markovnikov rule.

The part of the appendage that is negative (such as X ^– or Cl ^– / Br ^– ) usually goes to the carbon consisting of the fewest number of hydrogen atoms bonded to the carbon atom in Markovnikov’s rule; conversely, the part of the appendage that is negative is attached to the carbon atom that consists of the largest number of hydrogen atoms attached to the carbon atom in the anti-Markovnikov rule. The Markovnikov rule mechanism is an ionic mechanism in chemistry; on the other hand, the anti-markovnikov rule mechanism is a free radical mechanism. The reagents used in Markovnikov’s rule are HBr, HI, HCL, and H2 _.OR; on the other hand, the free reactant, which is used in the anti-markovnikov rule, is just HBr and not HCl, or HI undergone in this type of addition reaction.

No medium or catalyst is generally required in Markovnikov’s rule; on the other hand, the medium/catalyst is required which is peroxide or ultraviolet, which must be present to carry out the anti-markovnikov rule. Markovnikov accumulation of hydrogen halide to olefin results in the production of carbocation as a reaction intermediate; on the other hand, the creation of free carbon radicals as an intermediary of the reaction in the anti markovnikov rule. The attack on the carbon-carbon double bond is initiated by the hydrogen ion of the reactant HX in Markovnikov’s rule; on the contrary, the attack on the carbon-carbon double bond is usually initiated by halogen free radicals X which is produced by the communication between HX and the peroxide radical in the anti-Markovnikov rule.The main product is given by HBr of (CH ₃ ) 2C = CHCH ₃ will produce (CH ₃ ) 2CBrCH ₂ CH ₃ in Markovnikov’s rule; on the contrary, in the presence of peroxide, the main product will be given as (CH ₃ ) 2CHCH (Br) CH ₃ in an anti-Markovnikov addition reaction. In the Markovnikov addition reaction, the intermediate that is formed is the carbocation, then undergoes a rearrangement and increases the stability of the carbocation. In contrast, in the anti-Markovnikov rule, the produced intermediate does not undergo product rearrangement.

Comparison chart

What is Markovnikov’s rule?

Markovnikov’s rule explains that in some alkene or alkyne addition reactions, the proton is attached to that carbon atom that has a maximum number of hydrogen substituents attached to a carbon atom; Markovnikov’s rule helps calculate the end products of certain chemical reactions.

The following of the Markovnikov rule is due to the more stable product, i.e. the carbocation, which is the intermediate product of the Markovnikov rule. The stability of the carbocation increases when it undergoes rearrangements in chemical reactions. The participation of the hydrogen atom with the carbon atom forms the double bond on the carbon, which gives other vinyl carbon atoms a positive charge. To produce the stable final product, the carbocation must be a stable intermediate carbocation product. After the production of the precise carbocation, the Cl ^– binds to the positively charged carbon atom.

However, after the reaction is complete, a product mixture is produced, which is made up of products given by stable carbocation or unstable carbocation.

What is the anti Markovnikov rule?

The anti-Markovnikov rule explains that in various alkene and alkyne addition reactions, the proton binds to that carbon atom that has a minimum number of hydrogen atoms. The final product obtained from this rule is known as an anti-Markovnikov product. The carbocation is not formed in the anti-Markovnikov rule as an intermediate product. The anti markovnikov chemical reaction could be obtained in reactions that produce an anti markovnikov product by adding the catalyst peroxide as HOOH in the reaction mixture, which will then give carbon free radicals as anti markovnikov rule products.

A peroxide could alter the regioselectivity (the production of bonds on a specific atom above all other possible atoms) of an anti-Markovnikov addition reaction. The effect of peroxide takes a long time. This is why peroxide acts as a catalyst/medium in reactions against Markovnikov’s rule.

Key differences

1. Markovnikov’s rule generally describes that the proton is convolved with the carbon atom that has the largest number of hydrogen atoms attached. On the other hand, the anti markovnikov rule gives details that the proton is involved in that carbon atom which has a minimum number of hydrogen atoms attached to it.
2. According to Markovnikov’s rule, the hydrogen atom will always bond to that carbon atom that has a maximum number of bonded hydrogen substituents; conversely, according to the anti-Markovnikov rule, the hydrogen atom will always bond to the carbon atom with the fewest number of hydrogen substituents.
3. The electronegative part of the alkyl halide usually goes to carbon, which consists of the fewest number of hydrogen atoms bonded to a carbon atom in Markovnikov’s rule. In contrast, the electronegative part of the alkyl halide binds to the carbon atom consisting of the largest number of hydrogen atoms bonded to the carbon atom in the anti-Markovnikov rule.
4. The Markovnikov rule mechanism in chemistry is an ionic mechanism; on the other hand, the anti-markovnikov rule mechanism is a free radical mechanism.
5. HBr, HI, HCL, and H ₂ O are the reagents used in Markovnikov’s rule; on the other hand, HBr is the only free reactant used in the anti-Markovnikov rule, and HCl or HI do not undergo this type of addition reaction.
6. No medium is generally required in Markovnikov’s rule; on the other hand, to carry out the anti-Markovnikov rule, the medium that is peroxide or ultraviolet must be required.
7. The Markovnikov addition of hydrogen halide to the olefin normally results in the production of carbocation as a reaction intermediate; On the other hand, the creation of carbon free radicals is generally known as the reaction intermediate in the anti-Markovnikov rule.
8. In the Markovnikov addition reaction, the carbocation, which is the intermediate in this reaction, undergoes rearrangement, which increases the stability of the carbocation. In contrast, in the anti-Markovnikov rule, the intermediate produced does not undergo the rearrangement of the products.
9. The hydrogen ion from the reactant HX in Markovnikov’s rule initiates the attack on the carbon-carbon double bond. In contrast, the halogen free radical X, which is formed by communication between HX and the peroxide radical, generally initiates the attack on the carbon-carbon double bond in the anti-Markovnikov rule.
10. The main product is given by HBr of (CH ₃ ) 2C = CHCH ₃ will produce (CH ₃ ) 2CBrCH ₂ CH ₃ in Markovnikov’s rule; on the contrary, in the presence of peroxide, in the anti-Markovnikov addition reaction, the main product will be given as (CH ₃ ) 2CHCH (Br) CH ₃ .

Final Thought

The above discussion concludes that the Markovnikov and anti-Markovnikov rules are important in predicting the products of chemical reactions in which the Markovnikov rule describes that the proton is convolved with the carbon atom that has the maximum number of hydrogen atoms bonded to it. he; on the other hand, the anti-Markovnikov rule gives details that the proton is involved in that carbon atom which has a minimum number of hydrogen atoms attached to it.