Organic Synthesis Flashcards
Clean blue flame
Alcohol or ester
Yellow flame
Alkane
Smoky yellow flame
Unsaturated/aromatic compound
Insoluble in water; two layers form
London forces only in hydrocarbon
Partially soluble forming an emulsion
H-bonds in long chain alcohol or p.d.-p.d. or leave to settle
Soluble Homogenous Liquid
H-bonds in alcohol or acid
> C=C< test 1
Shake with Br water at room temp,
Orange–> colorless
RCH=CHR + HOBr –> RCHBrCHOHR (Bromoalcohol)
> C=C< test 2
Shake with dil. H2SO4 + KMnO4
Purple–> colourless (possible brown ppt)
RCH=CHR + [O] + H2O –> RCHOHCHOHR (Alkanediol)
C-Cl
C-Br
C-I
Use ethanol as solvent. warm with NaOH(aq). Acidify with dil. HNO3 and add AgNO3. ppt produced. add dil NH3, then conc. NH3
White ppt soluble in dil. NH3
Cream ppt soluble in conc. NH3
Yellow ppt insoluble in either
RCH3X + OH- –> RCH3OH + X-
X- + Ag- –> AgX (ppt)
C-OH test 1
PCl5, Anhydrous, room temp, test gas produced with conc. NH3
Steamy fumes produce white smoke with NH3
R-OH + PCl5 –> R-Cl + POCl3 + HCl
HCl + NH3 –> NH4Cl, white smoke
C-OH test 2
K2CR2O7 + Dil. H2SO4 (Acidified dichromate)
Orange sol. –> green/blue-green
C-OH test 3
Add small piece of sodium
Effervescence, sodium disappears, white solid produced
CH3CH2OH + Na –> CH3CH2O-Na+ H2(g)
Carbonyl Group Test
2,4-DNP + few drops conc. H2SO4 warm
Orange sol. forms orange/red crystals
2,4-dinitrophenylhydrazine–> 2,4-dinitrophenylhydrazone
practice mechanism
Test 1 to differentiate between aldehyde and ketone
Fehlings solution; add Fehlings A (Cu2+) and Fehlings B (tartrate) and warm
Blue solution–>red ppt
Cu2+(aq) + e- –> Cu+(s), therefore reducing group present, aldehyde
Aldehyde –> Carboxylic Acid
Test 2 to differentiate between aldehydes and ketones
Tollens Reagent; AgNO3(aq) + dil NH3 add to unknown and warm,
Colourless solution forms silver mirror on test tube sides
[Ag(NH3)2]+(aq) + e- –> Ag(s) + 2NH3(aq)
reducing agent present=aldehyde,
aldehyde–> carboxylic acid
Test for methyl ketone
Iodoform test; I2 crystal, shake with unknown, add dil. NaOH dropwise & warm
Pale yellow crystals with antiseptic smell
Crystals = CHI3, iodoform
RCHOHCH3 + [O] –> RCOCH3 + H2O, Methyl ketone
RCOCH3 + 3I2 + 4NaOH –> RCOO-Na+ + CHI3 + 3NaI + 3H2O
Sodium carbodylate salt + iodoform
RCOOH
litmus turns red
Add to carbonate e.g. NaHCO3, at room temp,
Effervescence, limewater turns milky
RCOOH –> RCOO- + H+
HCO3- + H+ –> H2O + CO2
Estherification; ROH, few drops of conc. H2SO4 and warm
Sweet smell
RCOOH + ROH –> RCOOR + H2O
Substitution: Nucleophilic
Halogenoalkane; RX
RX + OH- –> ROH + X-, alcohol
RX + CN- –> RCN + X-, nitrile (note, if carbon chain extends by, this probably has something to do with it
RX + NH3 –> RNH2 + HX, amine
Substitution: Electrophilic
Aromatics;
Benzene + HNO3/H2SO4 –> Nitrobenzene
Benzene + Cl2 AlCl3/FeCl3 –> Chlorobenzene
Benzene + RX/AlCl3 –> Alkyl benzene
Benzene + RCOCl/AlCl3 –> acylbenzene
Substitution: Free Radical
Alkanes + Halogen, X
Alkane + X2/UV –> Halogenoalkane
Addition: Nucleophilic
Carbonyl compounds + HCN –> Hydroxynitryl
Addition: Electrophilic
Alkene + Cl2 –> dichloroalkane
Alkene + HCl –> Chloroalkane
Addition: Polymerisation
Alkenes –> polymers
Oxidation: alkene
reagents and conditions: KMnO4 and dil NaOH(cold)/Diol
Product: Diol
