Lab 8: Preparation Of Alkenes By E1 And E2 Baeyer And Bromine Tests

Question 1

2-methyl-2-butanol with H2SO4

Answer 1

• E1 reaction (H2SO4)
• dehydration
• zaitsev favored

Question 2

2-chloro-2-methylbutane with KOH

Answer 2

• E2 (KOH + heat)
• dyhydrohalogenation
• zairsev favored

Question 3

Exceptions to zietsev rule: steric factors

Answer 3

• base bulky or substituent bulky on beta C = too much steric hinderance
• Hoffman favored

Question 4

Exceptions to zaitsev: stereoelectric factors

Answer 4

• only pertains to E2

- C-H and C-X are coplanar lie on same plane (doesn’t apply to E1 b/c stepwise)

Question 5

Bromine test

Answer 5

-if double or triple bond present will react

-Bromine addition reaction of Br2
across double or triple bond
-anti addition leading to cyclic bromonium
-vicinal dihalide

-rapid disappearance of orange/red to colorless is positive test

Question 6

Baeyer test

Answer 6

• lab 4
• if double bond or triple bond present will react with reagent
• positive test= purple to brown

Question 7

Factors that favor elimination

Answer 7

• strong bases
• steric hinderance around alpha carbon
• high temp.