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Shweta Thakur posted an Question

January 10, 2021 • 19:07 pm

30 points

IIT JAM
Chemistry (CY)

Why p isomer at low temperatures favourable and at high temperature ortho favourable . .in fries rearrangement

why p isomer at low temperatures favourable and at high temperature ortho favourable in fries rearrangement

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Priyanshu kumar Best Answer

At low temperature (<100°C) para isomer is the major product while at high temperature (>100°C) ortho isomer is the major product .This is because the intermediate of ortho isomer is stabilised by chelation ans is thermodynamically more stable. At higher temperatures thermodynamic prodcut is major product
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got this shweta?
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see this explanation...app is not working properly
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sir Kuch mistake ni hai
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got now?
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no
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kya nhi aaya samajh?
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sir kinetic controlled and thermodynamic controlled product difference
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A simple definition is that the kinetic product is the product that is formed faster, and the thermodynamic product is the product that is more stable
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chelation always leads to thermodynamically more stable product
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ok sir
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thanks sir
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welcome 🙂👍
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Dinesh khalmaniya 1

check it
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sir samagh ni aay
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Yha pt ortho major hoga because of H bonding, chelation hoga or product stable hoga
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sir but yhan temperature ke aspect main pooch ri hun ki why at hight ortho favours
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sir
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high temperature pr ortho complex bnta he so ortho majr product he.
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mene sb book me dekh liya or koi reason nhi diya
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yha pr high temperature pr thermodynamic more stable product bnta he ye apko yaad hi rkhna pdega
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yes sir sir ye experimental calculate Kiya Hoga
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yes
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thanku sir
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Suman Kumar

The orientation of the substitution reaction is temperature dependent. A low reaction temperature favors para substitution and with high temperatures the ortho product prevails, this can be rationalised as exhibiting classic Thermodynamic versus kinetic reaction control as the ortho product can form a more stable bidentate complex with the Aluminium.[5] Formation of the ortho product is also favoured in non-polar solvents; as the solvent polarity increases, the ratio of the para product also increases.
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can u plz explain this on paper
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This complex i am talking about
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why it is favourable at hight temp
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chelation is just a type of interaction it is not a proper bond so it needs higher temperature
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this is reason only???
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yes it is experimentally determined
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