Dehydration of 2-Butanol and Dehydrobromination of 2-Bromobutane; 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? CHEM 334 Expt 3 Lecture

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

Use this Set-up: Rubber septum Teflon tube Rubber septum Butenes 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

Gas Chromatography mixture 1) 2) 3) 4) compounds B A 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 mL GC 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