[ABA2015]

hi
which one of these reactions is faster and easier, why?

[billnotgatez]

Forum Rules require you show some work so we know where to help you
Please read forum rules

[ABA2015]

Forum Rules require you show some work so we know where to help you
Please read forum rules

I guess you think that question is my homework and I want someone help me , am I right? if so I'm not as bad as you think
 recently I have found in a us patent (us 5132327) that they convert 1,4-chloro benzene to 1,4-fluoro benzene to react with the mentioned amine, I'm not sure the conversion is necessary or not, so I wrote this question. by the way I do apologize if I have done something wrong.

[Babcock_Hall]

Even so, you should still give your attempt.  Why don't you start by telling us what you think the mechanism is?  Then perhaps the question of which reaction would be faster will come into better focus.

[ABA2015]

Why don't you start by telling us what you think the mechanism is?  Then perhaps the question of which reaction would be faster will come into better focus.

honestly, I think it is not necessary to convert Cl atoms to F because Cl must be a better leaving group cause C-Cl is weaker than C-F bond, and I really don't understand why this conversion has happen? may be dichloride benzene is more active than diflouro benzene! or something else the reaction scheme is shown below, sorry because of low quality

[orgopete]

Forum Rules require you show some work so we know where to help you
Please read forum rules

I guess you think that question is my homework and I want someone help me , am I right? if so I'm not as bad as you think
 recently I have found in a us patent (us 5132327) that they convert 1,4-chloro benzene to 1,4-fluoro benzene to react with the mentioned amine, I'm not sure the conversion is necessary or not, so I wrote this question. by the way I do apologize if I have done something wrong.

If you consider the patent as data, then it predicts the fluoride is a better leaving group. E.C. Taylor suggested that in an addition-elimination reaction, fluorine is smaller and results in less of a steric barrier to the initial addition.

[Babcock_Hall]

I think that this is likely to be a nucleophilic aromatic substitution reaction.

[clarkstill]

If you think about the rate-determining step of a nucleophilic aromatic substitution reaction it's clear why fluoride is better...