1. Knoevenagal reaction

2. Mechanism

3. Step 1-2 as explained in other reactions

4. Step 3: protonation: - alkoxide accepts a proton to form hydroxyl compound.

5. Step 4: involves dehydration

6. Mannich reaction

7. Reaction involves condensation of methanol which amine p an active methylene compound to form a Mannich base.

8. Mechanism:-

9. Step 1: formation of Imminium ion

10. Step 2: formation of carbanion

11. Step 3: attack by carbanion

12. Witting’s reaction

13. Reaction occurs between an aldehyde/ketone and phosphorous ylides to form substituted alkenes.

14. Phosphorous ylide is prepared by reacting a base with an alkyl triphenyl phosphonium halide as shown below

15. Mechanism

16. Step 1: attack by ylides

17. Structure B acts as the carbanion and initiates the nucleophilic attack on the carbonyl carbon to form betaine

18. Step 2: elimination of triphenyl phosphate oxide to yield an alkenes

19. In elimination reactions, atoms or groups are removed from a reactant.

20. When an alkyl halide undergoes elimination reaction, the halogen X is removed from a carbon and a hydrogen is removed from an adjacent carbon, a double bond is formed below the 2 carbons from which the atoms are removed e.g.

21. CH3 CHCH2CH3 + CHO3- → CH3CH =CH CH2CH3

22. Generally,

23. CH3 CH2CH2 X + Y- CH3CH2CH2Y + X-

24. ↓ Substitution reaction

25. CH3CH=CH2 + HY + X- (elimination reaction)

26. Factors affecting elimination reaction

27. Structure of the alkyl halide (RX)

28. Only secondary and primary alkyl halides undergo E1 reactions
Only secondary and primary alkyl halides undergo E1 reactions. The reaction proceeds through an intermediate of secondary carbocation which rearranges to the more stable tertiary carbocation. Base removes proton from β- carbon.

29. Primary, secondary and tertiary alkyl halides undergo E2 reactions
Primary, secondary and tertiary alkyl halides undergo E2 reactions. It is a one step mechanism involving bond breaking and bond formation.

30. Text for further reading

31. Organic chemistry – Brief course by Robert Atkins and Francis. A. Carey

32. Organic reaction mechanism, conversions and problems by R.L Madan

33. Because the bowling ball is raised to a greater height above the ground, its potential energy increases.

34. The ball has a mass of 5. 4kg, and it is lifted a distance of 1. 6 m
The ball has a mass of 5.4kg, and it is lifted a distance of 1.6 m. To calculate the work performed to raise the ball, we use both Equation 5.3 and for the force that is due to gravity:

35. (5.4 kg)(9.8m/s2)(1.6m)=85 kg-m2/s2=85j

36. When the ball is dropped, its potential is converted to kinetic energy
When the ball is dropped, its potential is converted to kinetic energy. At the instant just before

37. the ball hits the ground, we assume that the kinetic energy is equal to the work done in part(b), 85j:

38. Heat= (4.50 g CH4)(= -250j

39. ΔH = -196 kj

40. ΔH = kJ

41. ΔH = kJ

42. ΔH = kJ (i)

43. ΔH = kJ (ii)