Aldehydes, Ketones and Acids Notes
Aldehydes are organic compounds that contain a carbonyl group bonded to at least one hydrogen atom. The general formula for an aldehyde is RCHO, where R is an alkyl or aryl group. Aldehydes are used in the production of perfumes, flavors, and dyes. They are also used as solvents and as starting materials for the synthesis of other organic compounds.
Ketones are organic compounds that contain a carbonyl group bonded to two alkyl or aryl groups. The general formula for a ketone is RCOR', where R and R' are alkyl or aryl groups. Ketones are used in the production of solvents, fuels, and plastics. They are also used as starting materials for the synthesis of other organic compounds.
Methods of Preparation of Aldehydes and Ketones
From Alcohols
Aldehydes and ketones are generally prepared by the oxidation of primary and secondary alcohols respectively. Primary alcohols are oxidezed by PCC, secondary alcohols are oxidized by CrO3 and allylic alcohols are oxidized by MnO2.
A tertiary alcohol also gives ketone on oxidation but under extreme conditions.
When the vapours of alcohol are passed over the copper at 300°C, aldehydes and ketones are formed.
From Hydrocarbons
Ozonolysis of alkenes followed by hydrolysis gives aldehydes and ketones.
IIT-JEE(Main) Shift-2 Date:23.1.2025
Find the product in the given reaction
Solution:
Ozonolysis of alkene followed by hydrolysis gives carbonyl compounds.
Addition of water to ethyne in the presence of H2SO4 and HgSO4 gives acetaldehyde. All other alkynes give ketones in this reaction. This is Kucherov's Reaction.
Aromatic aldehydes (benzaldehyde and its derivatives) are prepared from aromatic hydrocarbons by the following methods
IIT-JEE(Main) Shift-1 Date:24.1.2025
Consider the following reaction
Product P is
Solution:
In the first step, addition of water to form ketone takes palce. In the second step, nucleophilic addition of HCN to that ketone followed by reduction in third step takes place to form amino alcohol.
From Aromatic Hydrocarbons
Strong oxidising agents oxidise toluene and its derivatives to benzoic acids. However, it is possible to stop the oxidation at the aldehyde stage with suitable reagents that convert the methyl group to an intermediate that is difficult to oxidise further. The following methods are used for this purpose.
A. Use of Chromyl Chloride (CrO2Cl2): Chromyl chloride oxidises methyl group to a chromium complex, which on hydrolysis gives corresponding benzaldehyde. This reaction is called Etard reaction.
IIT-JEE(Main) Shift-2 Date:22.1.2025
Solution:
B. Use of chromic oxide (CrO3): Toluene or substituted toluene is converted to benzylidene diacetate on treating with chromic oxide in acetic anhydride. The benzylidene diacetate can be hydrolysed to corresponding benzaldehyde with aqueous acid.
C. By Side Chain Chlorination followed by Hydrolysis: Side chain chlorination of toluene gives benzal chloride, which on hydrolysis gives benzaldehyde. This is a commercial method of manufacture of benzaldehyde.
By Gatterman – Koch Reaction: When benzene or its derivative is treated with carbon monoxide and hydrogen chloride in the presence of anhydrous aluminium chloride or cuprous chloride, it gives benzaldehyde or substituted benzaldehyde. This reaction is known as Gatterman-Koch reaction.
Friedel-Crafts Acylation
When benzene or substituted benzene is treated with acid chloride in the presence of anhydrous aluminium chloride, it affords the corresponding ketone. This reaction is known as Friedel-Crafts acylation reaction.
Gatterminann-Koch Formylation
Rosenmund's Reaction
Aldehydes can be prepared by passing hydrogen gas through a boiling solution of acid chloride in xylene in the presence Pd/BaSO4. Here the catalyst (Pd/BaSO4) is poisoned by sulphur or quinoline to avoid further reduction of aldehydes into alcohols.
Formaldehyde cannot be prepared by Rosenmund reduction. Why?
Formaldehyde cannot be prepared by Rosenmund reduction because the formyl chloride (HCOCl) is highly unstable at room temperature making it impossible to carry out the reduction reaction.
From Acyl Chlorides
Treatment of acyl chlorides with dialkylcadmium, prepared by the reaction of cadmium chloride with Grignard reagent, gives ketones.
2 R–Mg–X + CdCl2 → R2Cd + 2 Cl–Mg–X
2 R'–CO–Cl + R2Cd → R'–CO–R + CdCl2
From Nitriles and Esters
Nitriles are reduced to corresponding imine with stannous chloride in the presence of hydrochloric acid, which on hydrolysis give corresponding aldehyde. This reaction is called Stephen reaction.
Treatment of nitrile with Grignard reagent followed by hydrolysis yields a ketone.
Esters are also reduced to aldehydes with DIBAL-H.
Physical Properties of Aldehydes and Ketones
Odour or Smell
Aldehydes and ketones have pleasant smells. Lower aldehydes have unpleasant odors but when the size of the molecule increases the odor becomes less pungent and more fragrant.
Solubility
Aldehydes and ketones upto four carbon atoms are soluble in water due to hydrogen bonding. As the size of alkyl group increases solubility decreases. Solubility of aromatic aldehydes and ketones is lower than that of corresponding aliphatic aldehydes and ketones. All aldehydes and ketones are fairly soluble in organic solvents like benzene, ether, methanol, chloroform, etc.
Boiling Point
Aldehydes and ketones has weak intermolecular forces of attraction (dipole-dipole), so have low boiling point. Dipole-dipole intractions are, weaker than intermolecule H-bonding. Ketones have higher boiling points than isomeric aldehydes because of the presence of two electrons releasing groups around carbonyl carbon which makes them more polar. The boiling point of CH3–CH2–CHO is 322K while their isomeric ketone have boiling point 329k.
CH3–CH2–CHO < CH3–CO–CH3
Chemical Properties of Aldehydes and Ketones
Nucleophilic Addition Reactions
Due to the presence of carbonyl group, aldehydes and ketones undergo nucleophilic addition reactions. Aldehydes are generally more reactive than ketones in nucleophilic addition reactions due to steric and electronic reasons. Sterically, the presence of two relatively large substituents in ketones hinders the approach of nucleophile to carbonyl carbon than in aldehydes having only one such substituent. Electronically, aldehydes are more reactive than ketones because two alkyl groups reduce the electrophilicity of the carbonyl carbon more effectively than in former.
In nucleophilic addition reaction, nucleophile readily attacks the electrophilic carbon atom of the polar carbonyl group from a direction approximately perpendicular to the plane of the sp2-hybridized orbitals of the carbonyl carbon.
Why aldehydes are more reactive than ketones?
Aldehydes are generally more reactive than ketones in nucleophilic addition reactions due to steric and electronic reasons. Sterically, the presence of two relatively large substituents in ketones hinders the approach of nucleophile to carbonyl carbon than in aldehydes having only one such substituent. Electronically, aldehydes are more reactive than ketones because two alkyl groups reduce the electrophilicity of the carbonyl carbon more effectively than in former.
IIT-JEE(Main) Shift-1 Date:24.1.2025
Which of the following is most reactive towards nucleophilic addition reaction.
1. Para-nitro benzaldehyde
2. Para-methyl benzaldehyde
3. Benzaldehyde
4. Acetophenone
Solution:
The order of reactivity dependent on hinderance and electron deficiency (more positive) on carbonyl carbon.
Addition of Hydrogen Cyanide (HCN)
Aldehydes and ketones react with hydrogen cyanide (HCN) to yield cyanohydrins. This reaction occurs very slowly with pure HCN. Therefore, it is catalysed by a base and generated cyanide ion (CN–) being a stronger nucleophile readily adds to carbonyl compounds to yield corresponding cyanohydrin.
Addition of Sodium Hydrogensulphite
Sodium hydrogensulphite adds to aldehydes and ketones to form the addition products. The position of the equilibrium lies largely to the right hand side for most aldehydes and to the left for most ketones due to steric reasons. The hydrogensulphite addition compound is water soluble and can be converted back to the original carbonyl compound by treating it with dilute mineral acid or alkali.
Addition of Alcohols
Aldehydes react with one equivalent of monohydric alcohol in the presence of dry hydrogen chloride to yield alkoxyalcohol known as hemiacetals,
which further react with one more molecule of alcohol to give a gem-dialkoxy compound known as acetal.
Ketones react with ethylene glycol under similar conditions to form cyclic products known as ethylene glycol ketals. Dry hydrogen chloride protonates the oxygen of the carbonyl compounds and therefore, increases the electrophilicity of the carbonyl carbon facilitating the nucleophilic attack of ethylene glycol. Acetals and ketals are hydrolysed with aqueous mineral acids to yield corresponding aldehydes and ketones respectively.
Addition of Ammonia and its Derivatives
Ammonia and its derivatives H2N–Z add to the carbonyl group of aldehydes and ketones. The reaction is reversible and catalysed by acid. The equilibrium favours the product formation due to rapid dehydration of the intermediate to form >C=N-Z. Z = Alkyl, aryl, OH, NH2, C6H5NH, NH–CO–NH2, etc.
NOTE: Formaldehyde reacts with ammonia to form hexamethylenetetramine which is used as urinary antiseptic under the name urotropine.
Reduction of Carbonyl Compounds
Reduction to Alcohols:
Aldehydes and ketones are reduced to primary and secondary alcohols respectively by sodium borohydride (NaBH4) or lithium aluminium hydride (LiAlH4) as well as by catalytic hydrogenation.
RCOR (Ketones) can also be reduced to the corresponding secondary alcohols with aluminium isopropoxide in isopropyl alcohol. This reaction is called Meerwein-Ponndorf Verley Reduction.
Reduction to Hydrocarbons
The carbonyl group of aldehydes and ketones is reduced to CH2 group on treatment with zinc amalgam and concentrated hydrochloric acid (Clemmensen reduction) or with hydrazine followed by heating with sodium or potassium hydroxide in high boiling solvent such as ethylene glycol (Wolff-Kishner reduction).
IIT-JEE(Main) Shift-2 Date:29.1.2025
Solution:
It is Clemmensen reduction in which carbonyl group of aldehydes and ketones is reduced to CH2 group on treatment with zinc amalgam and concentrated hydrochloric acid
Aldehydes and ketones on heating with hydriodic acid and red phosphorus to 423K (150°C), it is reduced to the corresponding alkane, e.g.,
Reduction to Pinacols:
Ketones on reduction with magnesium amalgam and water form pinacols.
Oxidation of Carbonyl Compounds
Aldehydes differ from ketones in their oxidation reactions. Aldehydes are easily oxidised to carboxylic acids on treatment with common oxidising agents like nitric acid, potassium permanganate, potassium dichromate, etc. Even mild oxidising agents, mainly Tollens' reagent and Fehlings' reagent also oxidise aldehydes.
R–CHO → R–COOH
Ketones are generally oxidised under vigorous conditions, i.e., strong oxidising agents and at elevated temperatures. Their oxidation involves carbon-carbon bond cleavage to afford a mixture of carboxylic acids having lesser number of carbon atoms than the parent ketone.
During the oxidation of an unsymmetrical ketone, the cleavage of the C-CO bond is such that the keto group always stays with the smaller alkyl group.
Read Popoff's Rule
Oxidation of Methyl Ketones by Haloform Reaction
Aldehydes and ketones having at least one methyl group linked to the carbonyl carbon atom (methyl ketones) are oxidised by sodium hypohalite to sodium salts of corresponding carboxylic acids having one carbon atom less than that of carbonyl compound. The methyl group is converted to haloform. This oxidation does not affect a carbon-carbon double bond, if present in the molecule. Iodoform reaction with sodium hypoiodite is also used for detection of CH3CO group or CH3CH(OH) group which produces CH3CO group on oxidation.
What type of ketones undergo iodoform test?
The iodoform test is a chemical test that identifies compounds that contain the structural group CH3CO. Methyl ketones and secondary alcohols with a methyl group in the alpha position undergo the iodoform test.
Aldehydes and ketones are also oxidized by milder oxidants such as ammonical solution of silver nitrate (Tollen's reagent) and ammonical solution of cupric ions. Since cupric hydroxide is insoluble and is made soluble by complex formation either with tartarate ions (Fehling solution) or with citrate ions (Benedict's solution). Ketones are not oxidized by these reagents so it can be use to distinguish between aldehydes and ketone.
Tollen's Reagent
Oxidation of aldehyde is accompanied by reduction of silver ion to metallic silver which appears as mirror under proper conditions. Hence, the reaction is called the silver mirror test for aldehyde.
AgNO3 + NH4OH → AgOH + NH4NO3
2AgOH → Ag2O + H2O
RCHO + Ag2O → RCOOH + 2Ag↓ (Silver Mirror)
Fehlings' Solution
During the oxidation of aldehyde to acid, the cupric ions are reduced to cuprous ions which are precipitated as red cuprous oxide.
CuSO4 + 2NaOH → Cu(OH)2 + Na2SO4
Cu(OH)2 → CuO + H2O
2CuO + RCHO → RCOOH + Cu2O
IIT-JEE(Main) Shift-1 Date:22.1.2025
Which of the following will show positive Fehling test?
Solution:
C is the correct option.
Fehling test is given by aldehydes except benzaldehyde because it does not have an alpha hydrogen which is necessary for the formation of an enolate ion which is an intermediate step in the Fehling's test reaction.
Aldol Condensation
Aldehydes and ketones having at least one α-hydrogen undergo a reaction in the presence of dilute alkali as catalyst to form β-hydroxy aldehydes (aldol) or β-hydroxy ketones (ketol), respectively. This is known as Aldol reaction.
Crossed Aldol Condensation
When aldol condensation is carried out between two different aldehydes and / or ketones, it is called cross aldol condensation. If both of them contain α-hydrogen atoms, it gives a mixture of four products. This is shown below by aldol reaction of a mixture of ethanal and propanal. Ketones can also be used as one component in the cross aldol reactions.
IIT-JEE(Main) Shift-1 Date:23.1.2025
Identify the product formed in the following reaction
CH3−CH2−CHO + HCHO ⎯⎯OH⎯/Reflux⎯→
Excess
Solution:
Propanal undergoes aldol condensation with excess of HCHO in presence of OH– ions to 2, 2-dihydroxymethylpropanal which further reacts with HCHO and undergoes Cannizzaro reaction to given 2, 2-dihydroxymethylpropan-1-ol.
Cannizzaro Reaction
Aldehydes which do not have an α-hydrogen atom, undergo self oxidation and reduction (disproportionation) reaction on heating with concentrated alkali. In this reaction, one molecule of the aldehyde is reduced to alcohol while another is oxidised to carboxylic acid salt.
IIT-JEE(Main) Shift-2 Date:23.1.2024
When m-chlorobenzaldehyde is treated with 50% KOH solution, the product(s) obtained is
Solution:
When m-chlorobenzaldehyde is treated with 50% KOH solution, the products obtained are potassium meta-chloro benzoate and meta-chloro benzyl alcohol.
m-Chloro benzaldehyde have no alpha hydrogen atom. So, it undergoes cannizzaro reaction in which one molecule is oxidized to meta-chloro benzoic acid and other molecule is reduced to meta-chloro benzyl alcohol.
Crossed Cannizzaro Reaction
Crossed Cannizzaro reaction occurs when two different aldehydes or ketones react in the presence of a base. The more reactive aldehyde is oxidized, while the less reactive aldehyde is reduced.
C6H5–CHO + H–CHO + NaOH → C6H5–CH2–OH + H–COONa
Read more about Cannizzaro Reaction
Formaldehyde and benzaldehyde give cannizzaro reaction but acetaldehyde does not. Explain?
Cannizzaro reaction is a redox reaction that only occurs in aldehydes that do not have an α-H atom. Formaldehyde and benzaldehyde do not have an α-H atom, so they gives Cannizzaro reaction. Acetaldehyde has three α-H atoms, so it does not give the Cannizzaro reaction.
NOTE: All aldehydes (with or without α-hydrogens) can made to undergo Cannizzaro reaction on treatment with aluminium ethoxide. However, under these conditions, the alcohol and the acid produced as a result of Cannizzaro reaction, combine together to form esters. This reaction is known as the Tischenko reaction.
Reaction with Chlororform
Ketones, unlike aldehydes condense with chloroform in the presence of KOH to form chlorohydroxy compounds.
Halogenation
Aldehydes and ketones are readily halogentated whereby the hydrogen atoms on the carbon next to the carbonyl group are readily replaced by Cl, Br, or I atoms. This reaction is catalysed by acids and bases but occurs more readily with the latter.
Introduction of first halogen atom is slow but further substitution takes place faster due to the additional electron withdrawl of halogen atom already present.
Benzaldehyde has no α hydrogen atom, so chorine replaces the aldehydic hydrogen and form benzoyl chloride.
Ph–CHO + Cl2 → Ph–CO–Cl + HCl
Reaction with Grignard Reagent
Almost all aldehydes and ketones reacts with Grignard reagent to form adduct which upon hydrolysis with acid gives alcohols.
Perkin Reaction
When aromatic aldehyde is heated with the anhydride of an aliphatic acid in the presence of sodium salt of the same acid as a catalyst, α, β-unsaturated acid forms.
Read more about Perkin Reaction
Knoevenagel Condensation
Benzaldehyde undergoes condensation with substances containing active methylene group such as diethylmalonate, ethylacetoacetate or ethylcyanoacetate etc. in the presence of organic base such as piperidine or pyridine to form α,β-unsaturated esters which upon hydrolysis and heating give the respective α,β-unsaturated acids.
Read more about Knoevenagel Condensation
Reformatsky Reaction
Benzaldehyde reacts with α-halogentated esters in the presence of zinc to give βhydroxy esters.
Read more about Reformatsky Reaction
Electrophilic Substitution Reaction
Aromatic aldehydes and ketones undergo electrophilic substitution at the ring in which the carbonyl group acts as a deactivating and meta-directing group.
IIT-JEE(Main) Shift-1 Date:23.1.2025
The total number of isomers possible (aldehyde & ketones) for C4H8O are
Solution:
The total number of isomers possible (aldehyde & ketones) for
C4H8O are three.
Carboxylic acids are organic compounds that contain a carbonyl group bonded to a hydroxyl group (-OH). The general formula for a carboxylic acid is RCOOH, where R is an alkyl or aryl group. Carboxylic acids are generally produced by the oxidation of tertiary alcohols and from primary alcohols by strong oxidizing agent. Formic acid, Acetic acid, Benzoic acid etc. are the example of acids. Acids are polar molecules and the polarity makes them soluble in water. Carboxylic acids are used in the production of food, beverages, and pharmaceuticals. They are also used as solvents and as starting materials for the synthesis of other organic compounds.
Methods of Preparation of Acids
By the hydrolysis of Cyanides (R–CN)
Hydrolysis of cyanides by dilute HCl give acids.
R–C≡N + 2H2O → R–COOH + NH3↑
From Grignard Reagent and Carbon Dioxide
Grignard reagent on reaction with carbon dioxide followed by hydrolysis gives acids
From the Hydrolysis of Haloforms
Acids can also be prepared by the hydrolysis of haloforms.
By Oxidation of Carbonyl Compounds
By using strong oxidising agent like K2Cr2O7 or KMnO4 in acidic medium carbonyl compounds undergo oxidation to give carboxylic acids.
R–CHO + [O] → R–COOH
During oxidation of ketones the carbonyl group goes with smaller alkyl group according to Popoff's rule
R–CO–R → 2R–COOH
From amide (R–CONH2)
Amides on reaction with nitrous acid give carboxylic acids.
R–CO–NH2 + HNO2 → R–COOH + N2↑ + H2O
From Alkenes
On oxidative cleavage of alkenes by alkaline KMnO4 (hot) gives carboxylic acids. If the double bond in alkenes at terminal position formic acid is formed which further oxidizes into carbondioxide and water.
From Alkynes
Ozonolysis of alkynes followed by hydrolysis give acids.
From Acid Derivatives
Carboxylic acids can be prepared by the hydrolysis of acid derivatives.
R–CO–Z + H2O ⇌ R–COOH
R–CO–Cl + H2O ⇌ R–COOH
R–CO–NH2 + H2O ⇌ R–COOH
R–CO–R + H2O ⇌ R–COOH
From Toluene
Physical Properties of Acids
Carboxylic acids upto C3 – atoms are colourless liquids and pungent smelling & from C4 – C9 are rotten butter smelling colourless liquids.
Solubility
Due to hydrogen bonding lower acids upto C4 – atom are completely soluble in water. Solubility decreases with increase in molecular weight.
HCOOH > CH3COOH > C2H5COOH > C3H7COOH
Boiling Points
The boiling points of carboxylic acids are more than that of corresponding alcohols, acid derivatives or carbonyl compounds due to higher
extent of hydrogen bonding.
Remember: Boiling point of acids ∝ Molecular weight
HCOOH < CH3COOH < C2H5COOH < C3H7COOH
Melting Point
The melting point of an acid with even number of carbon atoms is more than the acid having next odd number of carbon atoms.
C4H9COOH > C5H11COOH
The —COOH group and R (alkyl group) in acids with even number of carbons, lie on opposite sides and hence provide a closer packing in the lattice and have high melting points.
Chemical Properties of Acids
Acidity of Carboxylic Acids and Its Derivatives
Carboxylic acids can dissociate in water to produce hydronium and carboxylate ions. The carboxylate ion, which is formed, will stabilise through the resonance by an effective delocalisation of the negative charge.
The strength of an acid is generally indicated by its pKa value rather than its Ka value.
pKa = – log Ka
Smaller the pKa, the stronger the acid.
Strong acids have pKa values < 1
Moderately strong acids have pKa values between 1 and 5
Weak acids have pKa values between 5 and 15
Extremely weak acids have pKa values >15.
Carboxylic acids are strongest acid among the organic compounds but they are weaker compared to mineral acids like HCl or H2SO4. The acidity of a carboxylic acid is higher compared to alcohols and even phenols. When carboxylic acids react with metals and the alkalis, they produce carboxylate ions which is stabilise by the resonance.
Electrons withdrawal groups increases the acidity of acids whereas an electron donation groups decreases their acidity.
CF3COOH > CCl3COOH > CHCl3COOH > NO2COOH > NC-CH2COOH
Formation of Anhydride
Carboxylic acids on heating with mineral acids such as H2SO4 or with P2O5 give corresponding anhydride.
Esterification
Carboxylic acids are esterified with alcohols or phenols in the presence of a mineral acid such as concentrated H2SO4 or HCl gas as a catalyst.
R—COOH + R'—OH ⇌ R—CO—OR' + H2O
Reactions with PCl5, PCl3 and SOCl2
The hydroxyl group of carboxylic acids, behaves like that of alcohols and is easily replaced by chlorine atom on treating with PCl5, PCl3 or SOCl2. Thionyl chloride (SOCl2) is preferred because the other two products are gaseous and escape the reaction mixture making the purification of the products easier.
R—COOH + PCl5 → R—CO—Cl + POCl3 + HCl
3 R—COOH + PCl3 → 3 R—CO—Cl + H3PO3
R—COOH + SOCl2 → R—CO—Cl + SO2 + HCl
Reaction with Ammonia
Carboxylic acids react with ammonia to give ammonium salt which on further heating at high temperature give amides.
R—COOH + NH3 ⇌ R—CO—ONH4 → R—CO—NH2
Reaction with NaHCO3
When a carboxylic acid reacts with sodium bicarbonate (NaHCO3), it produces carbon dioxide gas, water, and a sodium salt. This reaction is used to test for carboxylic acids.
R—COOH + NaHCO3 → R—COONa + CO2 + H2O
IIT-JEE(Main) Shift-1 Date:24.1.2025
When x g of Benzoic acid reacts with NaHCO3, 11.2 L of CO2 is released at 273 K and 1 atm pressure, calculate mass of benzoic acid in gram?
Solution:
Ph—COOH + NaHCO3 → Ph—COONa + CO2 + H2O
Moles of CO2 = 11.2/22.4 = 0.5mol
Moles of Benzoic acid = 0.5 mol
Mass of benzoic acid = 0.5 × 122 g = 61 g
Reaction with Urea
Carboxylic Acids reacts with urea to give acid amides.
R—COOH + NH2—CO—NH2 → R—CO—NH2 + NH3 + CO2
Reaction with Organometallics
Acids react with organo-metallic compounds to give alkanes.
R'—CH2—Mg—X + R—COOH → R'—CH3 + R—COOMgX
Reduction of Acids
Carboxylic acids are reduced to primary alcohols by lithium aluminium hydride or better with diborane. Diborane does not easily reduce functional groups such as ester, nitro, halo, etc. Sodium borohydride does not reduce the carboxyl group.
Decarboxylation of Carboxylic Acids
Carboxylic acids lose carbon dioxide to form hydrocarbons when their sodium salts are heated with sodalime (NaOH and CaO in the ratio of 3 : 1). The reaction is known as decarboxylation.
Halogenation of Carboxylic Acids
Carboxylic acids having an α-hydrogen are halogenated at the α-position on treatment with chlorine or bromine in the presence of small amount of red phosphorus to give α-halocarboxylic acids. The reaction is known as Hell-Volhard-Zelinsky reaction.
Schmidt Reaction
Acid reacts with hydrazoic acid (HN3) in presence of conc. sulphuric acid to give a primary amine.
R—COOH + HN3 → R—NH2 + N2 + CO2
Read more Schmidt Reaction
Birnbaum-Simonini Reaction
On heating a silver salt of a fatty acid with I2 in CCl4, an ester instead of iodoalkane is formed.
2R—COOAg + I2 → R—COOR + CO2 + AgI
Read more Birnbaum-Simonini Reaction
Hunsdiecker Reaction
Hunsdiecker reaction is also known as Borodin reaction or the Hunsdiecker–Borodin reaction in which silver salts of carboxylic acids react with a halogen to produce an organic halide. The product has one fewer carbon atoms than the starting carboxylic acid (lost as carbon dioxide) and a halogen atom is introduced its place.
Read more Hunsdiecker Reaction
Kochi Reaction
The decarboxylation of carboxylic acids to alkyl halides with lead(IV) acetate and a lithium halide is called Kochi Reaction. Kochi Reaction is a one-carbon oxidative degradation of carboxylic acids and is a variation of the Hunsdiecker reaction.
Read more Kochi Reaction
Electrophilic Substitution Reaction
Aromatic carboxylic acids undergo electrophilic substitution reactions in which the carboxyl group acts as a deactivating and meta-directing group. They however, do not undergo Friedel-Crafts reaction (because the carboxyl group is deactivating and the catalyst aluminium chloride (Lewis acid) gets bonded to the carboxyl group).
Benzoic acid do not undergo friedel craft reaction?
Benzoic acid doesn't undergo a Friedel-Crafts reaction because the carboxylic (COOH) group deactivates the benzene ring. This makes it difficult for the electrophile (carbocation) to attack the benzene ring.
Questions Answer
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