ORGANIC REACTIONS
Tests to identify the carbonyl compounds
-2,4 DNPH: colourless to reddish orange -Tollens Reagent test Reagent: AgNO3 in aq.NH3 (produces Ag+ ions acting as mild oxidising agent) Condition: Warm Colour change: Colourless to silver mirror -Fehlings test Reagent: Cu2+/ alkali (acts as mild oxiding agent) Condition: Warm Colour change: Blue to brown -Iodoform test Reagent: I2/NaOH Condition: Warm Colour change: Colourless to yellow ppt.
Preparation of aldehydes
-Partial oxidation of primary alcohol -Partial oxidation of alkene
Preparation of Ketone
-Partial oxidation of seconday alcohol -Partial oxidation of alkene
Substitution by CN-
Reagent: KCN in ethanol Condition: Reflux CN substitutes Cl to produce Cl- ion
Reduction of Carboxylic acids
Reagent: LiAlH4/ dry ether: acts as solvent for LiAlH4 Condition: Warm Carboxylic acid ---> Alcohol + H2O 2H is added to C and 2H is added to oxygen that's double bonded to C to form H2O
Substitution by NH3 in ethanol
Reagent: NH3 in ethanol Condition: Reflux Cl forms bond with H from NH3 to form H-Cl and NH2 takes place of Cl
Displacement of Alcohols
Reagent: Na Condition: Heat CH3CH2OH + Na --> CH3CH2ONa + 1/2H2
Reduction of Ketones
Reagent: NaBH4/Alkali Condition: Warm H is added to O double bonded to C and H is added to C involved in double bonding Alcohol formed
Reduction of Aldehydes
Reagent: NaBH4/Alkali Condition: Warmed H is added to O doubled bonded to C and H is added to C involved in double bonding Alcohol formed
Substitution by aqueous NaOH
Reagent: NaOH (aq) or KOH Condition: Reflux OH substitutes Cl to produce Cl- ion
Elimination reaction
Reagent: NaOH in ethanol Condition: Reflux HBr is removed to give NaBr and H2O
Hydrolysis of nitrile
Reagent: NaOH/ H2O Condition: Reflux CH3CH2CN ---> CH3CH2COONa + NH3 + H2O
Alkaline hydrolysis
Reagent: NaOH/H2O Condition: Reflux
Substitution by PCl3
Reagent: PCl3 Condition: Reflux 3CH3OH + PCl3 --> 3CH3Cl + 3H3PO3
Substitution by PCl5
Reagent: PCl5 Condition: Room temp. CH3CH2CH2OH + PCl5 --> CH3CH2CH2Cl + POCl3 + HCl
Substitution by SOCl2
Reagent: SOCl2 Condition: Reflux CH3CH2CH2OH + SOCl2 --> CH3CH2CH2Cl + SO2 + HCL
Substitution by X-
Reagent: X-/ aqueous Condition: Reflux Cl- > Br- > I- > CH3CH2Cl + Br- --> No reaction CH3CH2Br + Cl- --> CH3CH2Cl + Br-
Polymerisation reaction
Reagent: alkene Condition: High temp. and pressure Molecular formula remains the same Branch the methyl group Continuation shown by extended line at the ends
Substitution by dry HCl
Reagent: dry HCl Condition: Reflux C2H5OH + HCl --> C2H5Cl + H2O
Mechanism Of Nucleophilic Substitution
SN1: Substitution by a nucleophile where rate would be dependent upon 1 factor Tertiary halogenoalkane SN2: Substitution by a nucleophile where rate is dependent upon 2 factors Primary halogenoalkane
Preparation of Alcohol
SN2: Halogenoalkane reacts with aqueous NaOH to give alcohol and NaCl Electrophilic Addition: Alkene reacts with steam to give an alcohol
Alkanes
Saturated hydrocarbon Reactions: Complete combustion Incomplete combustion Free Radical Substitution
Oxidation of Aldehyde
gives carboxylic acid
Hydrolysis of esters
Acid hydrolysis Alkaline hydrolysis
Converting CH3CH2COONa to CH3CH2COOH
Acidification Reagent: H2O/H+ Condition: Reflux
Combustion of alcohols
Alcohol + oxygen --> carbon dioxide + water
Electrophilic addition mechanism
Br2 molecule becomes instantaneous dipole Double bond being nucleophile attracts Br+ and forms carbocation [slow step] Carbocation is organic intermediate Carbocation reacts with Br- [fast step]
Incomplete Combustion of Alkanes
CO, C, NOx + CxHy NOx: Engines run at a high temp. so nitrogen and oxygen in the air react Can lead to acid rain CO: Carboxyhaemoglobin; death C: Respiratory problems CxHy: Fuel effiency decreases
Catalytic Converter
Catalyst: Platinum/ Rhodium Redox reaction: CO + NOx--> CO2 + N2 CxHy --> CO2 + H2O
Initiation
Chlorine splits by homolytic fission in the presence of sunlight to produce 2 chlorine free radicals
Displacement of Carboxylic acids
Condition: Reflux CH3COOH + Na ---> CH3COONa + H2
Neutralization of Carboxylic acids
Condition: Reflux CH3COOH + NaOH --> CH3COONa + H2O CH3COOH + Na2CO3 --> 2CH3COONa + CO2 + H2O CH3COOH + NaHCO3 --> CH3COONa + H2O + CO2
Reaction of Carboxylic Acids
Displacement Neutralization Reduction
Production of alcohol
Fermentation: Anaerobic respiration of yeast at 37°C
Reduction of aldehyde & ketone
Gives alcohol
Oxidation of Ketones
No reaction
Oxidation of tertiary alcohol
No reaction
Halogenoalkanes
Obtained from free radical substitution Nucleophilic substitution reaction Elimination reaction
Propagation
One reactant is a radical and one product is a radical First step: The chlorine radical removes H from methane to produce hydrogen chloride and methyl radical Second step: The methyl radical reacts with Cl2 to produce CH3Cl and chlorine radical
Addition of halogens
Reagent: Br2/ H2O Condition: Room temp. Br is added to every carbon involved in double bonding
Free radical substitution
Reagent: Cl2 Solvent: H2O Condition: Sunlight Initiation Propagation Termination
Mild oxidation of alkenes
Reagent: Cold Diluted KMnO4/ H+ Condition: Room temp. OH is added to every carbon atom involved in double bonding Double bond broken to single bond
Dehydration of alcohols
Reagent: Conc. sulphuric acid/ Al2O3/ Pumice stone Condition: Heat CH3CH2OH --> CH2=CH2 + H2O H and OH is removed
Esterification
Reagent: Concentrated H2SO4 Condition: Reflux Carboxylic acid + Alcohol --> Ester + H2O OH from alcohol and H from carboxylic acid is removed to form water Forward reaction: conc. H2SO4 Reverse reaction: dilute H2SO4
Addition of hydrogen
Reagent: H2/ Nickel Condition: 140°c H is added to every carbon involved in double bonding
Acid hydrolysis
Reagent: H2O/ H+ Condition: Reflux Ester hydrolysed to carboxylic acid and alcohol
Addition of steam
Reagent: H2O/ conc. H3PO4 Condition: 330°c , 6Mpa H and OH is added Isomerism exists Alcohol with most alkyl groups is stable hence more percentage formed
Acidification
Reagent: H2O/HCl Condition: Reflux CH3COONa ----> CH3COOH + NaCl
Hydrolysis of nitrile
Reagent: H2O/HCl Condition: Reflux Cyanide --> Carboxylic acid + NH4Cl N, 2H2O and Cl form NH4Cl
Nucleophilic addition reaction
Reagent: HCN/NaCN (catalyst) Condition: Reflux H is added to O doubled bonded to C and CN is added to C involved in double bonding
Partial oxidation of alkene
Reagent: Hot conc. kMnO4/H+ Condition: Distill Oxygen is added to a carbon CO2 produced if CH2 present at the double bond H2O produced
Strong oxidation of alkenes
Reagent: Hot, conc. KMnO4/ H+ Condition: Reflux =CH2 --> CO2 + H2O =CH --> -COOH =C --> C=O
Partial oxidation of alkene
Reagent: Hot.conc. kMnO4/H+ Condition: Distill An oxygen is added to carbon atom If CH2 is present at double bond, CO2 is produced H2O is produced
Addition of Hx
Reagent: Hx Condition: Room temp. H and Cl is added Isomerism exists
Oxidation of alcohols
Reagent: K2Cr2O7/ H+ OR hot conc. KMnO4/H+ Condition: Reflux H2O produced as product Primary alcohol oxidized to carboxylic acid Secondary alcohol oxidized to ketone Tertiary alcohol --> no reaction
Partial oxidation of primary alcohol
Reagent: K2Cr2O7/H+ Condition: Distill Oxygen atom removes two H to form water & aldehyde
Oxidation of Aldehydes
Reagent: K2Cr2O7/H+ Condition: Reflux An oxygen is added to H to form carboxylic acid
Partial oxidation of secondary alcohol
Reagent: K2Cr2O7/H+ Condition: Reflux Oxygen atom removes 2H to form H2O and ketone
Nucleophilic Substitution reaction
Substitution by aqueous NaOH Substitution by KCN Substitution by NH3 Substitution by X-
Nucleophilic Substitution reaction
Substitution by dry HCl Substitution by SOCl2 Substitution by PCl5 Substitution by PCl3
Test for ketone
Tollens Reagent test: no reaction Fehling's test: no reaction
Termination
Two radicals join to form a molecule 2 chlorine radicals react to form chlorine 2 methyl radicals react to form ethane 1 methyl radical reacts with 1 chlorine radical to form CH3Cl
Alkenes
Unsaturated hydrocarbon Obtained from cracking of higher alkanes Any reaction over double bond is electrophilic addition reaction
Complete Combustion of Alkanes
alkane + oxygen -> carbon dioxide + water The number of CO2 is the same as the number of carbons in the alkane The number of H2o is half the number of hydrogen General Formula : CxHy + (x+y/4)O2-> xCO2 + y/2H2o
