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    Name:  461.jpg
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Size:  165.7 KB 1) Can anyone please explain to me how this works? I don't get what it means by No2 directs the substituent group.
    2) After cl2 is added, why is cl on the first carbon, also why are there 2 products formed, instead of just one?

    I am starting to learn this topic, so I only know a little of this, a simple explanation would be appreciated. Thanks.
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    (Original post by coconut64)
    Name:  461.jpg
Views: 231
Size:  165.7 KB 1) Can anyone please explain to me how this works? I don't get what it means by No2 directs the substituent group.
    2) After cl2 is added, why is cl on the first carbon, also why are there 2 products formed, instead of just one?

    I am starting to learn this topic, so I only know a little of this, a simple explanation would be appreciated. Thanks.
    Simply put, any attachment to the ring affects the electron density distribution around the ring. This has two significant effects:
    1. The reactivity of the ring may increase (activation) or decrease (depending on the type of substituent)
    2. Further substitution will occur at specific places preferentially.

    Substituent groups can be divided into:
    positive inductive (+I) - less electronegative than ring, eg methyl
    negative inductive (-I) - more electronegative than ring
    positive mesomeric (+M) - can donate an electron pair to the ring
    negative mesomeric (-M) - can withdraw an electron pair from the ring

    positive groups increase reactivity and direct towards the 2, 4, 6 positions
    negative groups decrease reactivity and direct towards the 3, 5 positions.

    halogens are anomalous as they are both -I and +M (deactivating and 2, 4, 6 directing)
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    (Original post by coconut64)
    Name:  461.jpg
Views: 231
Size:  165.7 KB 1) Can anyone please explain to me how this works? I don't get what it means by No2 directs the substituent group.
    2) After cl2 is added, why is cl on the first carbon, also why are there 2 products formed, instead of just one?

    I am starting to learn this topic, so I only know a little of this, a simple explanation would be appreciated. Thanks.
    There are two products as there are three positions in which further substitution can take place, 2 , 4, 6

    as chlorine is the first substituent its carbon is designated #1
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    (Original post by charco)
    There are two products as there are three positions in which further substitution can take place, 2 , 4, 6

    as chlorine is the first substituent its carbon is designated #1
    Why is there no substituent group on the sixth carbon since substitution can take place on carbon 6? Thanks.
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    (Original post by coconut64)
    Why is there no substituent group on the sixth carbon since substitution can take place on carbon 6? Thanks.
    The 2 position is the same as the 6 position, only viewed from the backside (ooh errr missus)

    If you are substituting one group then the product choice is 2 (and 6) or 4

    As there are two equivalent positions (2 & 6) then there is statistically twice as much probability (all other thinks being equal) of forming the 2 isomer as opposed to the 4 isomer.

    Imagine then the product yields would look like this:

    2-chloromethylbenzene - 67%
    4-chloromethylbenzene - 33%

    Of course there are other factors at play as well. For example there will problemy be also a small amount of the 3, 5 isomers formed.
    The 2 and 6 positions are sterically hindered by the substituent at the 1 position. This reduces the probability of a 2 or 6 substitution.

    So you might get something like:

    2-chloromethylbenzene - 59%
    4-chloromethylbenzene - 40%
    1% others
 
 
 
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