A Green Chemistry Module

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A Green Chemistry Module
Nucleophilic Aromatic Substitution
Presidential Green Chemistry Challenge Award
Elimination of Chlorine in the Synthesis of
4-Aminodiphenylamine. A New Process Which
Utilizes Nucleophilic Aromatic Substitution for
Hydrogen
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SNAr Mechanism - addition / elimination
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Benzyne Mechanism - elimination / addition
Step-wise formation of Benzyne
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Evidence for the Benzyne Mechanism
Trapping in Diels/Alder Reaction
Substrate Modification absence of a hydrogens
Isotopic Labeling
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SN1 Mechanism
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SNR1 Mechanism
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Brown Chemistry Route to 4-ADPA
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Atom Economy of the Traditional Chemistry
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Brown Chemistry
Nucleophilic Aromatic Substitution for Chlorine

• Large amount of chlorine
• storage
• handling
• Waste stream components
• inorganic salts
• organics
• Large amounts of water consumed
• Heavy metal catalyst

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Nucleophilic Aromatic Substitution for Hydrogen
General Mechanism
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Flexsys Route to 4-ADPA
Base-Promoted Coupling Reaction
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Flexsys - Anaerobic Oxidation to 4-NDPA
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Flexsys - Intermolecular Oxidation Pathway
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Atom Economy of the Flexsys Chemistry
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Green Chemistry Advantages for
Nucleophilic Aromatic Substitution for
Hydrogen

• Reduction in chemical waste generation
• elimination of
• 74 of organic waste
• 99 of inorganic waste
• Eliminates use of chlorine
• Reduction in waste water
• more than 97 savings
• Eliminates use of xylene
• a SARA chemical
• Improves process safety
• lower reaction temperatures