Contents

1. Structure
2. IUPAC Nomenclature
3. Preparations

Videos

Structure of Carbonyl Compounds

Preparation of aldehydes and ketones

Preparation – Sketch Notes

Ozonolysis of alkenes

Alkanoic acids Shorts

Carboxylic acids and carboxylates

Study Notes

Aliphatic Aldehydes (First 6 Members)

S.No	Molecular Formula	IUPAC Name	Common Name
1	HCHO	Methanal	Formaldehyde
2	CH₃CHO	Ethanal	Acetaldehyde
3	C₂H₅CHO	Propanal	Propionaldehyde
4	C₃H₇CHO	Butanal	Butyraldehyde
5	C₄H₉CHO	Pentanal	Valeraldehyde
6	C₅H₁₁CHO	Hexanal	Caproaldehyde

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Aliphatic Ketones (First 6 Members)

S.No	Molecular Formula	IUPAC Name	Common Name
1	CH₃COCH₃	Propan-2-one	Acetone
2	CH₃COC₂H₅	Butan-2-one	Methyl ethyl ketone
3	C₂H₅COC₂H₅	Pentan-3-one	Diethyl ketone
4	C₃H₇COCH₃	Pentan-2-one	Methyl propyl ketone
5	C₄H₉COCH₃	Hexan-2-one	Methyl butyl ketone
6	CH₃CO(CH₂)₃CH₃	Hexan-2-one	—

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Aliphatic Carboxylic Acids (First 6 Members)

S.No	Molecular Formula	IUPAC Name	Common Name
1	HCOOH	Methanoic acid	Formic acid
2	CH₃COOH	Ethanoic acid	Acetic acid
3	C₂H₅COOH	Propanoic acid	Propionic acid
4	C₃H₇COOH	Butanoic acid	Butyric acid
5	C₄H₉COOH	Pentanoic acid	Valeric acid
6	C₅H₁₁COOH	Hexanoic acid	Caproic acid

Popular Aromatic Aldehydes

S.No	Molecular Formula	IUPAC Name	Common Name
1	C₆H₅CHO	Benzaldehyde	Benzaldehyde
2	C₆H₄(CHO)-OH	4-Hydroxybenzaldehyde	p-Hydroxybenzaldehyde
3	C₆H₄(CHO)-CH₃	4-Methylbenzaldehyde	p-Tolualdehyde
4	C₆H₄(CHO)-NO₂	4-Nitrobenzaldehyde	p-Nitrobenzaldehyde
5	C₆H₄(CHO)-OCH₃	4-Methoxybenzaldehyde	p-Anisaldehyde

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Popular Aromatic Ketones

S.No	Molecular Formula	IUPAC Name	Common Name
1	C₆H₅COCH₃	1-Phenylethanone	Acetophenone
2	C₆H₅COC₆H₅	1,2-Diphenylethanone	Benzophenone
3	C₆H₄(COCH₃)-OH	4-Hydroxyacetophenone	p-Hydroxyacetophenone
4	C₆H₄(COCH₃)-NO₂	4-Nitroacetophenone	p-Nitroacetophenone
5	C₆H₄(COC₆H₅)-CH₃	4-Methylbenzophenone	p-Methylbenzophenone

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Popular Aromatic Carboxylic Acids

S.No	Molecular Formula	IUPAC Name	Common Name
1	C₆H₅COOH	Benzoic acid	Benzoic acid
2	C₆H₄(COOH)-OH	4-Hydroxybenzoic acid	p-Hydroxybenzoic acid
3	C₆H₄(COOH)-CH₃	4-Methylbenzoic acid	p-Toluic acid
4	C₆H₄(COOH)-NO₂	4-Nitrobenzoic acid	p-Nitrobenzoic acid
5	C₆H₄(COOH)-COOH	Benzene-1,2-dicarboxylic acid	Phthalic acid

General Methods of Preparation of Aliphatic Aldehydes

S.No	Method	Reaction	Reagents / Conditions
1	Partial Oxidation of Primary Alcohols	R–CH₂OH → R–CHO	Mild oxidizing agents like PCC (Pyridinium chlorochromate), DMP (Dess–Martin periodinane) or controlled oxidation using KMnO₄ / K₂Cr₂O₇
2	Hydroformylation of Alkenes (Oxo Process)	R–CH=CH₂ + CO + H₂ → R–CH₂–CH₂–CHO	Catalyst: Co or Rh complexes, high pressure
3	Rosenmund Reduction of Acyl Chlorides	R–COCl + H₂ → R–CHO	Catalyst: Pd/BaSO₄ poisoned with sulfur or quinoline
4	Stephen Reaction (from Nitriles)	R–CN + SnCl₂/HCl → R–CH=NH → R–CHO	Partial reduction followed by hydrolysis
5	Reduction of Esters	R–COOR’ → R–CHO	DIBAL-H at low temperature (–78 °C), followed by hydrolysis
6	From Acid Chlorides Using Lithium tri-tert-butoxyaluminum hydride	R–COCl → R–CHO	(LiAlH(OtBu)₃), mild and selective
7	Dry Distillation of Calcium Salts of Fatty Acids	(RCOO)₂Ca + heat → R–CHO + CaCO₃	Calcium formate + calcium salt of higher acid

These methods are primarily used for aliphatic aldehydes (e.g., acetaldehyde, propionaldehyde) and can be selected based on desired substrate and selectivity.

General Methods of Preparation of Aromatic Aldehydes

S.No	Method	Reaction	Reagents / Conditions
1	Formylation of Aromatic Compounds (Gattermann Reaction)	Ar–H + HCN + HCl → Ar–CHO	AlCl₃ or ZnCl₂ as catalyst
2	Gattermann–Koch Reaction	Ar–H + CO + HCl → Ar–CHO	Catalyst: AlCl₃ + CuCl, CO under pressure
3	Reimer–Tiemann Reaction (for phenols)	Ar–OH + CHCl₃ + NaOH → Ar–CHO	Heat, alkaline medium
4	Oxidation of Methyl Aromatic Compounds	Ar–CH₃ → Ar–CHO	Catalysts like CrO₃, MnO₂ (selective oxidants)
5	Hydrolysis of Benzal Chloride	C₆H₅CHCl₂ + 2H₂O → C₆H₅CHO + 2HCl	Heat with aqueous acid
6	From Aromatic Acid Chlorides (Rosenmund Reduction)	Ar–COCl + H₂ → Ar–CHO	Pd/BaSO₄ poisoned catalyst
7	Stephen Reaction (from Aromatic Nitriles)	Ar–CN + SnCl₂/HCl → Ar–CH=NH → Ar–CHO	Followed by hydrolysis

These methods are commonly used to prepare aromatic aldehydes like benzaldehyde, p-hydroxybenzaldehyde, and others. Choice of method depends on functional groups present and required selectivity.

General Methods of Preparation of Aliphatic Ketones

S.No	Method	Reaction	Reagents / Conditions
1	Oxidation of Secondary Alcohols	R₁–CHOH–R₂ → R₁–CO–R₂	Mild oxidizing agents like PCC, KMnO₄, or CrO₃
2	Friedel–Crafts Acylation (for methyl ketones like acetophenone)	R–COCl + R′–H → R′–CO–R	Anhydrous AlCl₃ catalyst, inert solvent (for aryl ketones)
3	Hydration of Alkynes	RC≡CH + H₂O → R–CO–CH₃	Hg²⁺/H₂SO₄ catalyst (Markovnikov addition)
4	From Nitriles	R–CN + R′MgX → R–CO–R′	Followed by acid hydrolysis
5	Reaction of Acid Chlorides with Dialkylcadmium	R–COCl + R′₂Cd → R–CO–R′	Dry ether, low temperature
6	Ketonic Decarboxylation	CH₃COONa + CH₃COONa → CH₃–CO–CH₃	Dry distillation of calcium or sodium salts of carboxylic acids
7	From Esters using Grignard Reagent (2 mol)	R–COOR′ + 2R″MgX → R–C(OMgX)R″₂ → R–CO–R″	Hydrolysis yields the ketone

These methods are applicable mainly for aliphatic ketones like acetone, butanone, pentanone, etc., and selected based on starting materials and target structure.

General Methods of Preparation of Aromatic Ketones

S.No	Method	Reaction	Reagents / Conditions
1	Friedel–Crafts Acylation	Ar–H + R–COCl → Ar–CO–R	Anhydrous AlCl₃, dry solvent like CS₂ or CH₂Cl₂
	Example: C₆H₆ + CH₃COCl → C₆H₅COCH₃	(Acetophenone)
2	From Aromatic Acid Chlorides and Dialkylcadmium	Ar–COCl + R₂Cd → Ar–CO–R	Dry ether, low temp
3	Reaction of Aromatic Nitriles with Grignard Reagent	Ar–CN + R–MgX → Ar–CO–R	Followed by acid hydrolysis
4	Oxidation of Secondary Alcohols	Ar–CH(OH)–R → Ar–CO–R	PCC, CrO₃ or KMnO₄ (mild oxidation)
5	Coupling of Acyl Radicals (From diazonium salt)	Ar–N₂⁺ + R–COCl → Ar–CO–R	CuCl as catalyst (Sandmeyer-like)
6	From Esters Using Grignard Reagent (2 eq.)	Ar–COOR′ + 2R–MgX → Ar–CO–R	Hydrolysis yields ketone

These methods are commonly used to synthesize aromatic ketones such as acetophenone, benzophenone, and substituted aryl alkyl ketones. Friedel–Crafts acylation is the most direct and widely used method.

General Methods of Preparation of Aliphatic Carboxylic Acids

S.No	Method	Reaction	Reagents / Conditions
1	Oxidation of Primary Alcohols	R–CH₂OH → R–COOH	Oxidizing agents: KMnO₄, K₂Cr₂O₇/H₂SO₄, or Jones reagent
2	Oxidation of Aldehydes	R–CHO → R–COOH	KMnO₄, K₂Cr₂O₇, Tollens’ reagent (Ag⁺), Fehling’s solution
3	Hydrolysis of Nitriles	R–CN + 2H₂O → R–COOH + NH₃	Acidic (HCl) or basic (NaOH) hydrolysis
4	Hydrolysis of Esters	R–COOR′ + H₂O → R–COOH + R′OH	Acidic or basic hydrolysis (saponification)
5	Carbonation of Grignard Reagent	R–MgX + CO₂ → R–COOMgX → R–COOH	Dry CO₂, then acidification with HCl
6	From Acid Halides or Anhydrides	R–COCl + H₂O → R–COOH	Simple hydrolysis
7	From Alkylbenzenes (Side Chain Oxidation)	R–CH₃ → R–COOH	KMnO₄ oxidation (mainly for aromatic acids but also for certain aliphatic chains)
8	From Malonic Ester Synthesis	CH₂(COOR)₂ → R–CH₂–COOH	Alkylation followed by hydrolysis and decarboxylation

General Methods of Preparation of Aromatic Carboxylic Acids

S.No	Method	Reaction	Reagents / Conditions
1	Oxidation of Alkylbenzenes (Side Chain Oxidation)	Ar–CH₃ → Ar–COOH	KMnO₄ (hot, alkaline), then acidify
	Example: Toluene → Benzoic acid
2	Hydrolysis of Aromatic Nitriles	Ar–CN + 2H₂O → Ar–COOH + NH₃	Acidic (HCl) or basic (NaOH) hydrolysis
3	Hydrolysis of Aromatic Esters	Ar–COOR + H₂O → Ar–COOH + ROH	Acid or base catalyzed hydrolysis
4	Carbonation of Aryl Grignard Reagents	Ar–MgX + CO₂ → Ar–COOH	Then acidify with dilute HCl
5	Hydrolysis of Aromatic Acid Chlorides	Ar–COCl + H₂O → Ar–COOH + HCl	Simple hydrolysis
6	From Diazonium Salts	Ar–N₂⁺ + H₂O → Ar–OH → Ar–COOH	Convert to phenol then oxidize
7	Koch Reaction (for activated aromatic rings)	Ar–H + CO + H₂O → Ar–COOH	Acid catalyst (H⁺), high pressure

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✅ Comparison Summary: Aliphatic vs Aromatic Carboxylic Acid Preparation

Feature	Aliphatic Carboxylic Acids	Aromatic Carboxylic Acids
Common starting materials	Primary alcohols, aldehydes, nitriles	Alkylbenzenes, aryl nitriles, aryl esters
Preferred oxidants	KMnO₄, K₂Cr₂O₇, Jones reagent	KMnO₄ (alkaline), CrO₃
Grignard route	R–MgX + CO₂ → R–COOH	Ar–MgX + CO₂ → Ar–COOH
Mild hydrolysis route	Esters, nitriles, acid chlorides	Esters, nitriles, acid chlorides
Unique to aromatic acids	Side-chain oxidation, diazonium hydrolysis	Not applicable to aliphatic acids

Day-to-Day Life Applications of Carbonyl Compounds

S.No	Compound	Type	Common Applications in Daily Life
1	Formaldehyde (HCHO)	Aldehyde	Preservative in labs, disinfectant, resin manufacturing
2	Acetaldehyde (CH₃CHO)	Aldehyde	Intermediate in synthesis of perfumes, vinegar, and flavors
3	Benzaldehyde (C₆H₅CHO)	Aromatic Aldehyde	Almond flavoring, perfumes, dyes
4	Vanillin (C₈H₈O₃)	Aromatic Aldehyde	Main component of vanilla essence in foods
5	Citral	Aldehyde	Lemon scent in cosmetics and air fresheners
6	Cinnamaldehyde	Aldehyde	Gives cinnamon aroma, used in food and fragrance
7	Acetone (CH₃COCH₃)	Ketone	Nail polish remover, solvent, degreasing agent
8	Butanone (MEK)	Ketone	Solvent for plastics, glues, printing inks
9	Camphor	Ketone	Used in balms, chest rubs, and insect repellents
10	Muscone	Ketone	Perfumes (musk fragrance)
11	Formic acid (HCOOH)	Carboxylic Acid	Ant sting component, preservative, leather tanning
12	Acetic acid (CH₃COOH)	Carboxylic Acid	Vinegar, food preservative, cleaning agent
13	Propionic acid	Carboxylic Acid	Food preservative in bakery products
14	Butyric acid	Carboxylic Acid	Found in rancid butter, contributes to flavor in cheese
15	Benzoic acid	Aromatic Acid	Food preservative (E210), antimicrobial agent
16	Salicylic acid	Aromatic Acid	Anti-acne creams, pain relievers (precursor to aspirin)
17	Citric acid	Carboxylic Acid	Found in citrus fruits, used in soft drinks and food as flavor enhancer
18	Lactic acid	Carboxylic Acid	Preservative, acidity regulator, found in fermented foods
19	Tartaric acid	Carboxylic Acid	Used in baking powders and as a stabilizer in food
20	Oxalic acid	Carboxylic Acid	Used to remove rust and ink stains, found in leafy vegetables

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🔎 Summary of Uses:

• Aldehydes → Flavors, fragrances, antiseptics
• Ketones → Solvents, cosmetics, medicinal use
• Carboxylic acids → Food preservatives, flavoring agents, pharmaceuticals, cleaning

Worksheets

Word Search in Alkanals

Word Search Challenge in Carbonyl Compounds

Online Quiz in IUPAC Naming

IUPAC Drill

Here is the worksheet for IUPAC Naming of Carbonyl Compounds (Fill in the blanks – 1 mark each):

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IUPAC Naming Worksheet

Q.No	Structure	IUPAC Name
1	CH₃CH₂CH₂CH₂CH₂CHO	______________________
2	CH₃COCH₂CH₂CH₂CH₃	______________________
3	CH₃CH₂COCH₃	______________________
4	CH₃COC₂H₅	______________________
5	CH₃CH₂CH₂CHO	______________________
6	CH₃CH₂CH₂CH₂CHO	______________________
7	C₆H₅COOH	______________________
8	CH₃CH₂CH₂COCH₃	______________________
9	C₆H₅COCH₃	______________________
10	CH₃CH₂CH₂CH₂CH₂CH₂CHO	______________________
11	HCOOH	______________________
12	CH₃COOH	______________________
13	C₆H₅CHO	______________________
14	CH₃COCH₃	______________________
15	CH₃CHO	______________________
16	CH₃COCH₂CH₂CH₃	______________________
17	CH₃CH₂CHO	______________________
18	CH₃CH₂CH₂CH₂CHO	______________________
19	HCHO	______________________
20	C₆H₅COC₆H₅	______________________

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📌 Scan the QR code below to view the answer key:

Two-mark Reasoning questions and problems based on the preparation of carbonyl compounds (aldehydes and ketones):

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I. Reasoning-Based Questions (Conceptual – Explain Why/How)

1. Why is PCC preferred over KMnO₄ for oxidation of primary alcohols to aldehydes?
2. Why can’t we use strong oxidizers like KMnO₄ to prepare aldehydes from alcohols?
3. Why does Rosenmund reduction selectively stop at aldehydes and not further reduce to alcohols?
4. Why is DIBAL-H used at low temperatures for partial reduction of esters to aldehydes?
5. Why is Friedel–Crafts acylation not feasible on deactivated aromatic rings like nitrobenzene?
6. Why does the oxidation of secondary alcohols give ketones and not acids?
7. Why is Gattermann–Koch reaction limited to benzene and activated aromatics?
8. Why are acid chlorides preferred over esters in Rosenmund reduction for aldehyde synthesis?
9. Why do ketones resist further oxidation unlike aldehydes?
10. Why is Grignard reagent followed by carbonation a reliable method for carboxylic acid preparation but not aldehyde or ketone?

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II. Problem-Based Questions (Short Calculations/Reaction Completion)

11. Convert: CH₃CH₂OH → CH₃CHO (mention reagents and conditions).
12. Complete the reaction: C₆H₆ + CH₃COCl → ? (with AlCl₃)
13. Write the reaction: CH₃CN → CH₃CHO (using Stephen reaction).
14. Identify the product: CH₃COCl + H₂ (Pd/BaSO₄ poisoned)
15. Write a reaction to prepare propanone from 2-propanol.
16. Name the product formed by oxidation of CH₃CH₂CH₂OH using mild CrO₃.
17. Predict the product of CH₃MgBr + CO₂ → ? (followed by H₃O⁺)
18. Give the steps to convert toluene to benzoic acid.
19. Write the reaction of Gattermann reaction on benzene using HCN and HCl.
20. How would you prepare acetophenone from benzene in one step?

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Clues and Keys for Two marks questions.

✅ Clues and Keys for the 20 Two-Marks Questions on Preparation of Carbonyl Compounds

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I. Reasoning-Based Questions (Clues + Key)

Q.No	Clue	Key (Answer)
1	Mild oxidizer needed to prevent over-oxidation	PCC is mild and oxidizes primary alcohols to aldehydes without further oxidation to acids
2	Strong oxidants don’t stop at aldehyde stage	KMnO₄ oxidizes aldehydes further to carboxylic acids
3	Catalyst is poisoned	Poisoned Pd/BaSO₄ limits hydrogenation only to aldehyde
4	To prevent over-reduction	DIBAL-H at –78°C stops at aldehyde; at higher temp it gives alcohol
5	Deactivated rings resist electrophilic substitution	Nitrobenzene is electron-deficient, so FC acylation doesn’t proceed
6	No hydrogen on carbonyl carbon	Secondary alcohols form ketones which lack α-H for further oxidation
7	Requires electron-rich ring	Gattermann–Koch fails with deactivated aromatics like nitrobenzene
8	Esters give alcohols or mixtures	Acid chlorides give aldehydes cleanly with Rosenmund reduction
9	Structure is resistant to oxidation	Ketones require strong oxidants and give complex mixtures; hence stable
10	Unstable intermediates	Grignard + CO₂ gives stable carboxylic acids; aldehydes not feasible

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II. Problem-Based Questions (Clues + Key)

Q.No	Clue	Key (Answer)
11	Mild oxidant	CH₃CH₂OH + PCC → CH₃CHO
12	FC acylation	C₆H₆ + CH₃COCl → C₆H₅COCH₃ (Acetophenone)
13	Stephen reaction	CH₃CN + SnCl₂/HCl → CH₃CH=NH → CH₃CHO
14	Rosenmund reduction	CH₃COCl + H₂ (Pd/BaSO₄) → CH₃CHO
15	Simple oxidation	CH₃CH(OH)CH₃ + PCC → CH₃COCH₃
16	Mild oxidation of primary alcohol	CH₃CH₂CH₂OH + CrO₃ → CH₃CH₂CHO
17	Grignard carbonation	CH₃MgBr + CO₂ → CH₃COOH
18	Side-chain oxidation	C₆H₅CH₃ + [O] → C₆H₅COOH
19	Gattermann reaction	C₆H₆ + HCN/HCl (ZnCl₂) → C₆H₅CHO
20	FC acylation	C₆H₆ + CH₃COCl + AlCl₃ → C₆H₅COCH₃

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