I like the OCR A answer (which doesn't have either SN1/SN2 or the inductive effect)... the rate of hydrolysis reactions depends on the strength of the C - X bond; adding alkyl groups to the C atom decreases the strength of the C - X bond. Cute.
So both are Sn1? But alcohols reacting with HCl isn't a nucleophilic substituion so why?
Tetiary alcohols react more easily as the hydroxyl group is more labile as loss leads to the formation of a tertiary carbocation, stabiised be theductive effect of three alkyl groups. It is a reversible reaction. As the concentration of chloride ions increases then they can substitute.
Tetiary alcohols react more easily as the hydroxyl group is more labile as loss leads to the formation of a tertiary carbocation, stabiised be theductive effect of three alkyl groups. It is a reversible reaction. As the concentration of chloride ions increases then they can substitute.
Ok so in tertiary halogenoalkanes the methyl groups push electrons away toward the C-X bond (due electron inductive effect) which makes the C-X bond weaker and makes the release of X- ion easier and it's the same for alcohols, just replace X with OH- right?
Tetiary alcohols react more easily as the hydroxyl group is more labile as loss leads to the formation of a tertiary carbocation, stabiised be theductive effect of three alkyl groups. It is a reversible reaction. As the concentration of chloride ions increases then they can substitute.
I can't process what exactly you're saying, I feel confused. Where does the conc of chloride ions come from?
Tetiary alcohols react more easily as the hydroxyl group is more labile as loss leads to the formation of a tertiary carbocation, stabiised be theductive effect of three alkyl groups. It is a reversible reaction. As the concentration of chloride ions increases then they can substitute.
You've got yourself confused, there. This is hydrolysis of the bromoalkane, rather than substitution of the alcohol.
You've got yourself confused, there. This is hydrolysis of the bromoalkane, rather than substitution of the alcohol.
As I see it they are effectively the same reaction/equilibrium:
ROH + HBr <==> RBr + HOH
Under acidic conditions the reaction shifts to the RHS Under basic conditions the reaction shifts to the LHS
The same argument should apply when comparing primary and tertiary structures. Any structural units favouring the formation of a carbonium ion (carbocation) should increase the rate of the reaction.
If you look at the ease of reaction with the Lucas test for alcohols, the tertiary alcohol gives an immediate positive test with equimolar HCl/ZnCl2, indicating the formation of RCl, while the secondary alcohols need about five or so minutes. The primary alcohols do not give a positive result at room temperature.
The same argument should apply when comparing primary and tertiary structures. Any structural units favouring the formation of a carbonium ion (carbocation) should increase the rate of the reaction.
If you look at the ease of reaction with the Lucas test for alcohols, the tertiary alcohol gives an immediate positive test with equimolar HCl/ZnCl2, indicating the formation of RCl, while the secondary alcohols need about five or so minutes. The primary alcohols do not give a positive result at room temperature.
Isn't that nucleophilic substitution? It isn't reversible in the george facer book
What's the Lucas test?
That's my point. Effectively, all reactions are reversible under suitable conditions.
Nucleophilic substitution of haloalkanes is a reaction controlled using suitable reagents (NaOH/aq) and conditions that allow the reaction to go to (virtual) completion. BUT The reverse reaction, substitution of a halogen into an alcohol also occurs under suitable conditions (ZnCl2/HCl).