ORTHO PARA DIRECTING EFFECT
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ORTHO PARA DIRECTING EFFECT
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| Some groups direct the second incoming group to the ortho and para positions simultaneously. These groups are called ortho-para directors. For example, when aniline is chlorinated, the product so obtained is ortho and para. | ||
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| The (-NH2) group directs the incoming group -Cl to ortho and para positions on the ring. Therefore, (-NH2) group is an ortho-para director.Some common ortho para directing groups are –Cl, -Br, -I, -OH, -NH2, -CH3, -C2H5. | ||
SOME ORTHO PARA DIRECTORS
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| Halogens , -NH2, -R, -OH | ||
META DIRECTING EFFECT
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| The group which directs the second incoming group to the meta position, is called a meta-director. For example, alkylation of nitro benzene gives m-alkylnitro benzene as major product. | ||
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| Therefore, –NO2 group is a meta director. | ||
SOME META DIRECTORS
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| -NO2, -CHO, -COOH, COOR, –SO3H, -CN, -COR etc. | ||
| For latest information , free computer courses and high impact notes visit : www.citycollegiate.com | ||
EFFECTS OF SUBTITUENTS ON REACTIVITY
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| Substituents already present on a benzene ring also influences the rate of reaction. For example, toluene, C6H5-CH3, is nitrated 25 times faster than benzene itself. On the other hand, the rate of nitration of chlorobenzene, C6H5-Cl is 30 times less than benzene. This means that the presence of CH3 on benzene ring activates it to aromatic electrophilic substitution, while the presence of a (-Cl) group deactivates it. A substituent, which activates the aromatic ring to further substitution, is called an activating substituent or ring-activator. A substituent, which deactivates the aromatic ring to further substitution, is called a deactivating substituent or ring-deactivator | ||
ORTHO PARA DIRECTING EFFECT
| ||
ORTHO PARA DIRECTING EFFECT
| ||
| Some groups direct the second incoming group to the ortho and para positions simultaneously. These groups are called ortho-para directors. For example, when aniline is chlorinated, the product so obtained is ortho and para. | ||
| ||
| The (-NH2) group directs the incoming group -Cl to ortho and para positions on the ring. Therefore, (-NH2) group is an ortho-para director.Some common ortho para directing groups are –Cl, -Br, -I, -OH, -NH2, -CH3, -C2H5. | ||
SOME ORTHO PARA DIRECTORS
| ||
| Halogens , -NH2, -R, -OH | ||
META DIRECTING EFFECT
| ||
| The group which directs the second incoming group to the meta position, is called a meta-director. For example, alkylation of nitro benzene gives m-alkylnitro benzene as major product. | ||
| ||
| Therefore, –NO2 group is a meta director. | ||
SOME META DIRECTORS
| ||
| -NO2, -CHO, -COOH, COOR, –SO3H, -CN, -COR etc. | ||
| For latest information , free computer courses and high impact notes visit : www.citycollegiate.com | ||
EFFECTS OF SUBTITUENTS ON REACTIVITY
| ||
| Substituents already present on a benzene ring also influences the rate of reaction. For example, toluene, C6H5-CH3, is nitrated 25 times faster than benzene itself. On the other hand, the rate of nitration of chlorobenzene, C6H5-Cl is 30 times less than benzene. This means that the presence of CH3 on benzene ring activates it to aromatic electrophilic substitution, while the presence of a (-Cl) group deactivates it. A substituent, which activates the aromatic ring to further substitution, is called an activating substituent or ring-activator. A substituent, which deactivates the aromatic ring to further substitution, is called a deactivating substituent or ring-deactivator | ||
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