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Date: 4-7-2019
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Date: 28-1-2022
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Date: 28-1-2022
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As the table below shows, the dissociation energy for the allylic C-H bond is lower than the dissociation energies for the C-H bonds at the vinylic and alkylic positions. This is because the radical formed when the allylic hydrogen is removed is resonance-stabilized. Hence, given that the halogen concentration is low, substitution at the allylic position is favored over competing reactions. However, when the halogen concentration is high, addition at the double bond is favored because a polar reaction outcompetes the radical chain reaction.
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دواء جديد يعطي الأمل لمرضى الانزلاق الغضروفي
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آلة زمن للمستقبل.."ميتا" تكشف عن نموذج لنظارات الواقع المعزز
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بالفيديو: في مستشفيات العتبة الحسينية.. ممثل المرجعية العليا أول المستقبلين للجرحى اللبنانيين
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