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Aldehydes and Ketones - Both aldehydes and ketones contain carbonyl group C=O. - The difference between aldehyde and ketone was found to be: In aldehyde.

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Presentation on theme: "Aldehydes and Ketones - Both aldehydes and ketones contain carbonyl group C=O. - The difference between aldehyde and ketone was found to be: In aldehyde."— Presentation transcript:

1 Aldehydes and Ketones - Both aldehydes and ketones contain carbonyl group C=O. - The difference between aldehyde and ketone was found to be: In aldehyde C=O attach with H and R i.e In ketone C=O attach with two R

2 Nomenclature of Aldehydes and Ketones
General formulae of aldehyde and ketones Nomenclature of Aldehydes and Ketones I) IUPAC: A) Aldehyde 1- يتم ذكر أسم alkane باستبدال حرف e في alkane بمقطع al e.g. Methane Methanal Ethane Ethanal

3 يتم ذكر أسم alkeneباستبدال حرف e في alkene بمقطع al
2 - لأن مجموعة CHO توجد غالبا في طرف السلسلة فلا يذكر رقمها 3- في حالة وجود فروع يتم ترقيم السلسلة بإعطاء مجموعة الألدهيد بالرقم 1 Examples: 4- ي حالة احتواء السلسلة علي يتم ذكر أسم alkeneباستبدال حرف e في alkene بمقطع al

4 Examples: 5- فى حالة احتواء السلسلة علي
يتم ذكر أسم alkyne باستبدال حرف e في alkyne بمقطع al Examples:

5 2) Common name تتم بذكر اسم الحمض محذوفا منه مقطع oic و استبداله ب aldehyde Examples ;

6 يتم ذكر أسم alkane باستبدال حرف e في alkane بمقطع one
B) Iupac nomenclature of ketones يتم ذكر أسم alkane باستبدال حرف e في alkane بمقطع one Example: Propane Propanone 2 - يتم ترقيم السلسة من الطرف الذي يعطي ل C=O أقل ترقيم Common system of ketones: -نذكر أسماء alkyl حول C=O ثم نكتب كلمة ketone في النهاية.

7 بعض الأسماء التي يجب حفظها

8 Preparation of aldehydes & ketones:
From acid chloride: This method is called Rosemund reduction. ملحوظة: فائدة Pd-BaSO4 catalyst انه يوقف الاختزال عند مرحلة ald. ولا يختزل ald. إلى كحول.

9 (2) From geminal dihalide: أي ذرتي هالوجين على نفس ذرة الكربون
Question: convert toluene to benzaldehyde Answer

10 (3) Partial decarboxylation of salt of acids:
Question: Show how could you prepare the following To prepare by above method, we use two molecules

11 الطريقة السابقة تستخدم لتحويل الأحماض إلي الدهيد أو كيتون كالأتي
Question: Show how could you prepare the following الطريقة السابقة تستخدم لتحويل الأحماض إلي الدهيد أو كيتون كالأتي Example conversion of

12 Methods have been studied :
(4) From nitrile: a- Aldehyde: b- Ketone Methods have been studied :

13 (5) Oxidation of alcohols:
a- Aldehyde: From oxidation of primary alcohol. b- Ketone: From oxidation of secondary alcohol.

14 (6) Ozonolysis of alkene :

15 (7) Hydration of alkyne :
Only other alkyne except acetylene will give ketone

16 Synthesis of aromatic ketones via Friedel-Crafts acylation:
E.g. Acetophenone For benzophenone

17 Synthesis of benzaldehyde
Gattermann-Koch aldehyde synthesis b) Gattermann aldehyde synthesis

18 Chemical reactions of aldehydes & Ketones
A-Type I of reaction (Addition reaction) تعتمد هذه التفاعلات علي إضافة H لذرة O وباقي المركب ل C Examples of this addition is addition of HCN, H2, RMgX, HOH, NaSO3H

19 Some observations يسمى ناتج إضافة HCN بذكر اسم aldehyde أو ketone متبوعاً بـ cyanohydrin. يمكن شرح ميكانيكية إضافة HCN كالأتي يسمى ناتج إضافة NaSO3H بذكر اسم aldehyde أو ketone متبوعاً بـ bisulphite. إضافة NaSO3H تتم فقط علي Aldehydes أو methyl Ketones ( )

20 E.g. these ketones does not add NaSO3H
ناتج إضافة H2O غير ثابت و يفقد H2O ثانية مكونا Aldehyde الأصلي و لكن يوجد بعض اتج إضافة H2O ثابتة مثل

21 Special cases of addition reactions
Benzoin condensation b) Formation of hemiacetals and acetals

22 B-Type II of reaction [addition reaction followed by loss of H2O]
e.g. (Condensation with amines) أي Ald. Or Ketones يتفاعل معamines بالإضافة العادية متبوعة بفقد H2O Examples:

23

24 C-Type III of reaction (Base catalyzed reaction)
1- Aldol condensation: - It occurs between two aldehydes or two ketones containing α-Hydrogen.. Mechanism:

25 - Other example: Mechanism:

26 Mechanism of formation of crotanaldehyde
In case of mixture of acetaldehyde and acetone , we obtain four products Mechanism of formation of crotanaldehyde

27 Mechanism of formation of Mestyl oxide
Mechanism of formation of 3-methyl-2-butenal

28 Mechanism of formation of 3-penten-2-one

29 2- Cannizaro reaction: - It occurs between two aldehydes with no α-hydrogen in presence of base to give an alc. and an acid.

30 3- Clasien condensation ;
Question: Show the effect of NaOH on acetaldehyde and benzaldehyde 3- Clasien condensation ; 4- Perkin condensation: D-Type IV of reaction (Different types of reaction)

31 Oxidation of aldehyde ketones:
Aldehydes can also oxidized by Tollens reagent [Ag(NH3)2OH]. Ketones are difficult for oxidation

32 Haloform reaction: It occurs with aldehyde or ketones containing
The only aldehyde gives Iodoform reaction is acetaldehyde Methyl ketones ( ) only can give iodoform only for example These ketones cannot give iodoform because they do not have

33 Examples of iodoform equation :
Mechanism: ملحوظة: يعتبر تفاعل الهالوفورم أكسدة لـ ald. او ketone إلى حمض مع فقد ذرة كربون واحدة.

34 Reduction of aldehydes & Ketones:
1- Reduction by catalytic hydrogen: It converts aldehyde or ketone to alcohol.

35 2- Reduction to hydrocarbon:
أي تحويل ald. او ketone إلى alkane. For examples;

36 a- Clemmensen reduction:
b- Walf-Kishner reduction:

37 3- Reduction with sod. Borohydride (NaBH4):
4- Reduction with Mg:

38 Replacement of oxygen by halogen:
PCl3, PCl5 or SOCl2 convert C=O into Example: PCl3, PCl5 or SOCl2 convert –OH to -Cl

39 The reaction of aldehyde or ketones with PCl3, PCl5 or SOCl2, can be used to convert aldehyde or ketones alkyne as follow e.g. conversion of acetone to propyne Halogenation of α-carbon:

40 In case of aromatic aldehyde or ketones.
In absence of Fe or FeCl3 catalyst In this case the reaction occur at α-carbon to C=O or in H of CHO

41 b) In absence of Fe or FeCl3 catalyst
Aldehydes and ketones are m- directing group, so orient halogen in m- position

42 Polymerization reaction
Only aldehydes can polymerize Examples a) Polymerization of formaldehyde in presence of water B )Polymerization of formaldehyde and acetaldehyd of presence of H2SO4

43


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