organic reactions- CIE AS level chemistry 9701

alkene to alcohol

+ steam

H3PO4 catalyst

300°C

60atm

Alkene to Halogenoalkane

+ HBr

room temp

alkene to alkane

H2, Ni catalyst, 150°C

Alkene to dihalogenoalkane

+Br2

room temp

alkene to diol

+ cold dilute acidified KMnO4

e.g. CH3CH=CH2 +[O]+H2O --> CH3CH(OH)CH2OH

alkene and hot, concentrated KMnO4

double bond ruptured and constituent molecules oxidised

halogenoalkane to alcohol

+ NaOH (aq), heat under reflux

nucleophilic sub

primary halogenoalkanes= Sn2 mechanism

tertiary halogenoalkanes= Sn1 mechanism

halogenoalkane to amine

+ excess conc NH3 (ethanolic)

heat and high pressure

nucleophilic sub

halogenoalkane to nitrile

+ KCN (ethanolic)

heat under reflux

nucleophilic sub

nitrile to amine

LiAlH4 in dry ether

Na in ethanol

H2 and nickel/platinum catalyst

halogenoalkane to alkene

NaOH (ethanolic)

heat under reflux

elimination reaction

alcohols to aldehydes

+KMnO4 (acidified) or K2Cr2O7 (acidified)

simple distillation

Alcohol to sodium alkoxide (and observations)

+ Na (produces H2)

effervescence

Na decreases in size

white solid formed (sodium alkoxide)

or + NaOH (produces H2O)

white solid formed (sodium alkoxide)

alcohols to carboxylic acids

+KMnO4 (acidified) or K2Cr2O7 (acidified)

heat under reflux

alcohols to chloroalkanes

ROH + PCl5 --> RCl +POCl3 + HCl

NaCl+ H2SO4 --> HCl (in situ) + NaHSO4

ROH + HCl --> RCl +H2O

ROH+ SOCl2 --> RCl + SO2 + HCl

all room temp

alcohol to bromoalkane

moist red 2P+ 3Br2 --> 2PBr3

3ROH + PBr3 --> 3RBr +H3PO3

NaBr + 50% H2SO4 --> NaHSO4 + HBr

ROH+ HBr --> RBr + H2O

both heat under reflux

alcohol to iodoalkane

moist red 2P + 3I2 --> 2PI3

3ROH + PI3 --> RI + H3PO3

alcohol to alkene

H3PO4/ conc H2S04/ Al2O3

heat

Reduction of Aldehydes and Ketones

+ LiAlH4 in dry ether or + NaBH4 (aq) (both provide hydride ion)

room temp

Aldehyde to Hydroxynitrile

KCN +H2SO4 --> HCN

catalyst: excess KCN

heat under reflux

HCN/KCN is toxic so perform in a fume cupboard

Nitriles to carboxylic acids

RCN + HCl + 2H2O --> RCOOH + NH4Cl

RCN +NaOH + H2O --> RCOONa + NH3

RCOONa + HCl/ H2SO4 --> RCOOH

both heat under reflux

hydroxynitriles to hydroxyamines

LiAlH4 in dry ether

or H2 and nickel catalyst

test for aldehydes/ketones

2,4-DNP (aka Brady's reagent)

yellow/orange solution, when reacts with aldehyde or ketone produces an orange ppt

nucleophilic addition- elimination reaction

iodoform test

reagents: I2 +NaOH (aq) + KI (aq)

detects:

ketones with a methyl group next to C=O

secondary alcohols with a methyl group next to C-O

ethanol

ethanal

reagent

if any of the above present, pale yellow crystals of iodoform (CHI3) are produced with antiseptic smell

e.g. propanone

RCOCH3(aq) + 3I2(aq) + 4NaOH(aq) ⇒ RCOONa(aq) + 3H2O(l) + 3NaI(aq) + CHI3(s)

test for carboxylic acids

add metal carbonate, bubble effervescence produced into limewater, if limewater is milky then presence of COOH

carboxylic acid to sodium alkyloate

+Na ;produces hydrogen effervescence)

+NaOH

+Na2CO3 ;produces CO2 effervescence, Na2CO3 decreases in size

carboxylic acid to alcohol

LiAlH4 in dry ether, room temp

CH3COOH + 4[H] --> CH3CH2OH + H2O

forming esters

carboxylic acid + alcohol, conc H2SO4 catalyst

heat

hydrolysis of esters

HCl catalyst (or any other strong acid)

if we wanted to hydrolyse it without it being an equillibrium reaction:

RCOOR + NaOH (aq) --> RCOONa + ROH

RCOONa + strong acid --> RCOOH + sodium salt

acid and alkali method both are heat under reflux