CHEM L13 RJ by YEO XUE NING, JANINE

DIFFERENT TYPES OF REACTIONS

200217683 — 2022-02-15 12:09:24 UTC

Reactions of Alcohols

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1. Combustion:

Ethanol + Oxygen -> Carbon dioxide + water
A reaction where a fuel is ignited in the presence of oxygen to produce heat energy and an oxide compound

2. Dehydration:

Ethanol + Sulfuric acid + heat (180 degrees celsius) -> Ethene + water
Alcohols lose water and form alkenes in the presence of a strong acid and heat
Tertiary alcohols are the easiest to dehydrate, followed by secondary then primary alcohols

3. Oxidation

Primary/Secondary alcohols are oxidized to form carboxylic acids, aldehydes and ketones
Ethanol + Pyridinium chlorochromate -> Ethanal
Ethanol + Chromic acid -> Ethanoic acid
Ethanol + permanganate -> Ethanoic acid
2-butanol + Pyridinium chlorochromate/Chromic acid/permanganate -> 2-butanone

4. Reactions of phenol

Phenol + Sodium -> sodium phenoxide + H2
Phenol + Sodium Hydroxide + carbon dioxide + heat + H+ -> salicylic acid
Phenol + concentrated nitric acid -? 2,4,6-trinitrophenol
Phenol + dilute nitric acid -> orthonitrophenol + paranitrophenol

5. Deprotonation with active metals

Ethanol + sodium -> sodium ethoxide + hydrogen
Alcohols undergo deprotonation with active metals to give corresponding alkoxides and hydrogen gas
Most acidic strength is primary alcohol, followed by secondary then tertiary alcohols

6. Substitution reaction

Primary, secondary and tertiary alcohols undergo nucleophilic substitution reactions with hydrogen halide to form alkyl halides and water
Primary alcohols undergo SN2
Secondary and tertiary alcohols undergo SN1
Tertiary alcohols undergo SN1 faster than secondary alcohols

Reactions of Aldehydes

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1. Nucleophilic addition reaction

aldehyde reacts with a nucleophile to form a hemiacetal
when aldehyde reacts with a nucleophile, the double bond is broken and the carbonyl carbon bonds with a hydroxyl group and the nucleophile
example: ethanal and hydrogen cyanide - the cyanide ion first approaches the carbonyl carbon and forms a bond with it, causing the electrons shared by C=O to be repelled towards oxygen, giving oxygen a negative charge, where oxygen ion then forms a bond with the hydrogen ion from hydrogen cyanide to form cyanohydrin.
nucleophilic addition can result in a racemic mixture of both optical isomers if the aldehyde is a planar molecule, where the nucleophile will attack the molecule from both the above and the bottom of the plane

2. Oxidation reaction

aldehydes can be oxidized to form carboxylic acids using KMnO4
the hydrogen atom bound to the carbonyl carbon binds to an oxygen atom, forming a hydroxyl group

3. Reduction reaction

aldehydes can be reduced to form primary alcohols using LiAlH4
the C=O breaks to a single bond, a hydrogen atoms binds to the carbonyl carbon and another hydrogen atom binds to the oxygen atom bonded to the carbonyl carbon, forming a hydroxyl group

4. Reaction with Grignard reagent

aldehydes react with Grignard reagents and water to form an alcohol
when aldehyde reacts with Grignard reagent, the C=O is broken into a single bond, the carbonyl carbon binds to CH2CH3 and the oxygen atom bonded to the carbonyl carbon binds to a hydrogen atom to form a hydroxyl group
Grignard reagents can be used to make primary, secondary and tertiary alcohols

5. Condensation reaction

aldehydes react with 2,4-dinitrophenylhydrazine to give a yellow to orange precipitate through a condensation reaction, where the yellow and orange precipitate indicates the presence of the C=O
when aldehydes react with 2,4-dinitrilephenylhydrazine, the C=O is broken, and the oxygen atom bonded to the carbonyl carbon forms a double bond with the nitrogen atom in 2,4-dinitrilephenylhydrazine
during this process, there is a loss of water

Reactions of Ketones

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1. Nucleophilic addition reaction

ketones can react with nucleophiles
when ketone reacts with a nucleophile, the double bond is broken and the carbonyl carbon bonds with a hydroxyl group and the nucleophile
example: ethanone and hydrogen cyanide - the cyanide ion first approaches the carbonyl carbon and forms a bond with it, causing the electrons shared by C=O to be repelled towards oxygen, giving oxygen a negative charge, where oxygen ion then forms a bond with the hydrogen ion from hydrogen cyanide to form cyanohydrin.
nucleophilic addition can result in a racemic mixture of both optical isomers if the ketone is a planar molecule, where the nucleophile will attack the molecule from both the above and the bottom of the plane

2. Reduction reaction

ketones can be reduced to form secondary alcohols using LiAlH4
when ketones react, the C=O is broken into a single bond, a hydrogen atom binds to the carbonyl carbon and another hydrogen atom binds to the oxygen atom bonded to the carbonyl carbon

3. Reaction with Grignard reagent

ketones react with Grignard reagents and water to form an alcohol
when ketones reacts with Grignard reagent, the C=O is broken into a single bond, the carbonyl carbon binds to CH2CH3 and the oxygen atom bonded to the carbonyl carbon binds to a hydrogen atom to form a hydroxyl group
Grignard reagents can be used to make primary, secondary and tertiary alcohols

4. Condensation reaction

ketones react with 2,4-dinitrophenylhydrazine to give a yellow to orange precipitate through a condensation reaction, where the yellow and orange precipitate indicates the presence of the C=O
when ketones react with 2,4-dinitrilephenylhydrazine, the C=O is broken, and the oxygen atom bonded to the carbonyl carbon forms a double bond with the nitrogen atom in 2,4-dinitrilephenylhydrazine
during this process, there is a loss of water

Reactions of Carboxylic acids

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1. Neutralization reaction

carboxylic acids react with aqueous alkali to form carboxylate salt and water
RCOOH + NaOH -> RCOO-Na+ +H2O
carboxylic acids also react with carbonates to form carboxylate salt, carbon dioxide and water
2RCOOH + Na2CO3 -> 2RCOO-Na+ +CO2 + H2O

2. Reaction with metal

carboxylic acids react with metals to produce salt and hydrogen gas
2RCOOH + 2Na -> 2RCOO-Na+ + H2

3. Condensation reaction

carboxylic acids react with alcohols and heat in the presence of an acid catalyst to form esters
it is a reversible reaction
water is lost in the process
RCOOH + R'OH <-> RCOOR' + H2O

4. Reduction reaction

carboxylic acids can be reduced to primary alcohols using LiAlH4
firstly, carboxylic acid is reduced into an aldehyde, then reduced further to a primary alcohol
RCOOH + 4[H] -> RCH2OH + H2O

5. Reaction with thionyl chloride (SOCl2), phosphorous trichloride (PCl3) or phosphorous pentachloride (PCl5)

carboxylic acids can react with thionyl chloride (SOCl2), phosphorous trichloride (PCl3) or phosphorous pentachloride (PCl5) to form acyl chlorides
CH3COOH + SOCl2 -> CH3COCl + HCl +SO2
CH3COOH + PCl5 -> CH3COCl + POCl3 + HCl
3CH3COOH + PCl3 -> 3CH3COCl + H3PO3

Reactions of Acyl chlorides

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1. Hydrolysis

acyl chlorides react vigorously with water to form carboxylic acid and hydrogen chloride gas
when acyl chlorides react with water, the bond between the carbonyl carbon and chlorine breaks and a bond between the carbonyl carbon and a hydroxyl group forms
RCOCl + H2O -> RCOOH + HCl
acyl chloride reacts vigorously with hydroxide ions to produce salts and water
RCOCl + 2NaOH -> RCOO-Na+ + NaCl + H2O

2. Condensation reaction

acyl chlorides react with alcohols to produce esters and hydrogen chloride gas
RCOCl + R'OH -> RCOOR' + HCl
acyl chlorides react with the hydroxyl group in phenols to produce esters and hydrogen chloride gas
RCOCl + phenol -> RCOOC6H6 + HCl
acyl chlorides react with ammonia to form primary amides
RCOCl + NH3 -> RCONH2 + HCl
acyl chlorides react with primary amines to form secondary amides
RCOCl + R'NH2 -> RCONHR' + HCl
acyl chlorides react with secondary amines to form tertiary amides
RCOCl + R'R''NH + RCONR'R'' + HCl

Reactions of Alkyl chlorides

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1. Hydrolysis

alkyl chlorides react with water to form alcohol and hydrogen chloride gas
RCl + H2O -> ROH + HCl
alkyl chlorides react with hydroxide ions to produce alcohol and a salt
RCl + NaOH -> ROH + NaCl

Reactions of Esters

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1. Hydrolysis

esters react with water and dilute acid to form carboxylic acids and alcohols
this reaction is reversible
RCOOR' + H2O <-> RCOOH + R'OH
esters also react with dilute alkali in the presence of heat to form carboxylate salts and alcohols
RCOOR' + NaOH -> RCOO-Na+ + R'OH
the carboxylate salts can be converted to carboxylic acids by adding excess strong aqueous acid

Reactions of Amines

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1. Reaction with acids

amines can react with strong acids to form a salt
amine gains a proton while the acid loses a proton
amines can also react with weak acids to form a salt
both aliphatic and aromatic amines form stable crystalline salts, that are soluble in water, with mineral acids

2. Nucleophilic substitution reaction

primary amines can react with primary alkyl halides to form secondary amines
secondary amines can react with primary alkyl halides to form tertiary amines
tertiary amines can react with primary alkyl halides to form quaternary ammonium salt
primary and secondary amines can react with acyl halides and ammonia to form amides

3. Electrophilic substitution reaction

phenylamine reacts with aqueous bromine to form 2,4,6-tribromophenylamine which can be seen as a white precipitate
phenylamine reacts with aqueous chlorine to form 2,4,6-trichlorophenylamine which can be seen as a white precipitate

Reactions of Amides

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1. Basic hydrolysis

primary amides react with a metal hydroxide and heat to form carboxylate ion and ammonia
secondary amides react with a metal hydroxide and heat to form carboxylate ion and a primary amine
both reactions occur in an aqueous base

2. Acid hydrolysis

primary and secondary amides react with hydrochloric acid and water in the presence of heat to form carboxylic acid, ammonium ion and a chloride ion

3. Reduction reaction

amides react with LiAlH4 in dry ether to form amines
the amide carbonyl group (C=O) is converted to methylene group (-CH2)
primary amides form primary amines after the reaction
secondary amides form secondary amines after the reaction