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Today:. Expt. #8 Dehydration of 2-Butanol and Dehydrobromination of 2-Bromobutane; Analysis of Products by GC. Structure of 2-butanol? How many 2-butanols are there….? Structure of 2-bromobutane?. Dehydration of 2-Butanol Reaction equation? Mechanism? Rate equation?
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Today: Expt. #8 Dehydration of 2-Butanol and Dehydrobromination of 2-Bromobutane; Analysis of Products by GC
Structure of 2-butanol? How many 2-butanols are there….? Structure of 2-bromobutane?
Dehydration of 2-Butanol Reaction equation? Mechanism? Rate equation? Energy Diagram? What intermediate(s) is(are) formed? What product(s) can we expect?
MW 56.11 BP 0.9oC MW 56.11 BP 3.7oC MW 56.11, BP -6.3oC
B: = Base b Reaction Diagram? Rate equation? Similarly: leading to 1-butene
K. L. Williamson, Macroscale and Microscale Organic Experiments, 2nd. Edition, D.C. Heath, 1994, p.275 Use this Set-up: Rubber septum Teflon tube Rubber septum Butenes Collection tube Reaction tube H2O Sand bath
K. L. Williamson, Macroscale and Microscale Organic Experiments, 2nd. Edition, D.C. Heath, 1994, p.269 Gas Chromatography With packed column mixture 1) 2) 3) 4) compounds B A
GC Conditions: Sample injection volume: 5 -10 mLGC column: 2m x 2mm (I.D.) Stationary Phase: 0.19% Picric acid on Carbograph 2, 80/100 Oven temperature: 60oC Moving Phase: Helium Column head pressure: 35 psi or more Injector temperature: 66oC Detector temperature: 100oC Detector: Thermal Conductivity Detector (TCD)
GC Chromatogram of products of the dehydration of 2-butanol reaction 3 2 Air Peak 1 Peak Area Time (min) r.t. (min)
Report Form #8 Part III, Question 2: What is the maximum volume at STP of the butene mixture that could be obtained by the dehydration of 160 mg of 2-butanol? STP? PV = nRT Units! Use correct R…
Next Friday: no classes (Veterans Day)Following Friday Lab Lecture:Exp.9, “Separation and Identification of an Unknown Mixture” (3 lab periods); IR, recryst., mp. s and other techniques you learnt this semester