Lecture_6 - Announcements Recrystallization Lab Report due...

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Unformatted text preview: Announcements Recrystallization Lab Report due “Next Week” (finish in lab) Calculation of % Yield in a Multi-Step Processes Post-Mortem Recrystallization of Acetanilide 1) Crystal Quality v.s. Yield Decolorizing Carbon & Hot Filtration 2) Crystal Forms Needles v.s. Plates Post-Mortem Recrystallization of Acetanilide 2) Crystal Forms Needles v.s. Plates On the Importance of the “Proper” Crystal form or Crystals that go BOOM !!! Post-Mortem Esterification Revisited 1) Refluxing a reaction mixture 2) The importance of venting “Early & Often” Thermowell & Clamps Apparatus Disassembly & Cooling Post-Mortem Esterification Revisited 3) Sodium Bicarbonate as an extraction reagent. 4) Fisher Esterification Reaction Mechanism (p913 Loudon) Post-Mortem Esterification Revisited 4) Fisher Esterification Reaction Mechanism (p913 Loudon) Acid Alcohol Ester Fisher Esterification Equilibrium with moderate K K= [Ester] [Water] [Acid] [Alcohol] = ~1-5 Fisher Esterification Excess Sulfuric Acid 5) Control of Equilibrium Position by: [Reactant Concentration] Choice of Acid catalyst Fisher Esterification 6) Other Acids as Catalysts HCl [conc] = 12 M (37% acid) HNO3 [conc] = 14 M (70% acid) 7) Removal of drying agent (MgSO4) Filter Tube Next Week Complete Synthesis of Methyl Benzoate 2-Step Distillation Required Simple – removes CH2Cl2 Vacuum – purifies Methyl Benzoate Steam Bath Next Week Complete Synthesis of Methyl Benzoate Nitration of Methyl Benzoate [Be careful handling acids – gloves] Recrystalize using MINIMUM amount of MINIMUM hot methanol (CH3OH) Mechanism of Nitration - Isomers Flowchart Next Week Thin Layer Chromatography Practice with pure methyl benzoate Save Nitration samples for TLC a) Crude (unrecrystallized) nitration solid b) Methanol wash from Vacuum filtration c) Recrystallized nitration product ...
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This note was uploaded on 02/25/2009 for the course CHEM 2510 taught by Professor Russo,s during the Fall '07 term at Cornell.

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