Organic reagents Flashcards
What does Br2 in CCl4 react with and what are the observations?
Alkenes to form dibromoalkane: reddish-brown bromine decolourised
Phenols/phenylamines to form monobromo derivative: reddish-brown bromine decolourised
Alkanes/alkyl chains with heat or uv: reddish-brown bromine decolourised
What is the rxn when Br2 in CCl4 react with alkenes/ phenols and phenylamines/ alkanes and alkyl chains?
alkenes: EA
phenols/phenylamines: ES
alkanes/alkyl chains: FRS
What does Br2 with anhydrous FeBr3 or AlBr3 or Cl2 with anhydrous FeCl3 or AlCl3 react with? What is the reaction and observation?
benzene/substituted benzene to monobromo/chloro derivative formed
ES rxn
reddish-brown bromine decolourised
What does Br2(aq) react with? What is the reaction and observation?
alkenes to bromoalcohol formed
EA rxn
orange/brown solution decolourised
What does Br2(aq) react with other than alkenes? What is the reaction and observation?
phenols/phenylamines to tri-bromo derivative formed
ES rxn
orange/brown solution decolourised + white ppt formed
What does AgNO3(aq) react with? What is the reaction and observation?
acid chlorides: hydrolysis
white ppt (AgCl)
acid bromides: hydrolysis
cream ppt (AgBr)
What does H2O(l) react with? What is the reaction and observation?
acid halides to carboxylic acid and halogenoalkane: hydrolysis
white fumes
RCOX + H2O -> RCO2H + HX
(X= Cl/Br)
What does Hbr(g) generated from NaBr with conc. H2SO4 and heat react with? What is the reaction and observation?
alcohols
bromine replaces -OH grp
substitution rxn
CH3CH2-OH + HBr -> CH3CH2-Br + H2O
What does HCl(g) with anhydrous ZnCl2 catalyst react with? What is the reaction and observation?
alcohols
chlorine replaces -OH grp
substitution rxn
CH3CH2-OH + HCl -> CH3CH2-Cl + H2O
What does 2,4-DNPH react with? What is the rxn and observation?
aldehydes/ketones to form hydrazone derivative
condensation rxn
orange ppt formed
What does Fehling’s soution warm react with? What is the rxn and observation?
aldehydes (except benzaldehyde)
oxidation rxn : Cu2+ reduced to Cu+(Cu2O)
reddish-brown ppt formed
What does Tollens’ reagent (Ammonical silver nitrate) warm react with? What is the rxn and observation?
aldehydes and benzaldehyde
oxidation rxn: Ag+ reduced to Ag(s)
silver mirror formed
What does I2(aq) with NaOH(aq) warm react with? What is the rxn and observation?
alcohols with methyl group/ carbonyls with methyl group
yellow crystals of tri iodomethane(CHI3) formed
What does HCN (with trace of NaOH or with trace of KCN) cold react with? What is the rxn and observation?
aldehydes and ketones
NA rxn : CH3COCH3 + HCN -> (CH3)2C(OH)CN
carbon chain extended by one 2 functional grps on one carbon atom
What does dilute acids (HCL,H2SO4) heat react with? What is the rxn and observation?
nitriles/amides/esters acid hydrolysis : CH3CN + H+ +2H2O -> CH3C02H + NH4+ CH3CONH2 + H+ + H2O -> CH3C02H + NH4+ CH3CO2CH3 + H2O -> CH3C02H + CH3OH
What does conc. H2SO4 react with? What is the rxn and observation?
alkenes
EA rxn
CH2=CH2 + H2O -> CH3CH2OH
What does excess conc. H2SO4 heat (170 degrees) react with? What is the rxn and observation?
alcohols: -OH and -H atom removed to form alkene
elimination rxn
What does conc. H2SO4 heat react with? What is the rxn and observation?
alcohols + carboxylic acids
condensation rxn
conc. sulfuric acid is used as catalyst removing water from rxn pushing the eqm. to favour production of esters
What does conc. HNO3 with H2SO4 (55/30 degrees) react with? What is the rxn and observation?
55 degrees: benzenes to nitrobenzene
ES rxn
pale yellow liquid
30 degrees: alkylbenzenes to nitromethylbenzene
ES rxn
pale yellow liquid
What does conc. HNO3 react with? What is the rxn and observation?
phenols tri-substitution occurs
ES rxn
yellow solid
mono-sub when dilute nitric acid used
What does neutral FeCl3(aq) react with? What is the rxn and observation?
phenols
complex formation
violet colouration
What does KMnO4 with dil. H2SO4 heat react with? What is the rxn and observation?
look at notes
What does dilute KMnO4 with NaOH(aq) cold react with? What is the rxn and observation?
alkenes to produce diols
mild oxidation
purple KMnO4 decolourised and black ppt of MnO2 formed
What does dilute K2Cr2O7 with dil H2SO4 heat/heat with immediate distillation react with? What is the rxn and observation?
primary alcohol to carboxylic acid/secondary alcohol to ketone/aldehydes to carboxylic acid
oxidation
orange solution turns green
immediate distillation: primary alcohols to aldehydes
oxidation
orange solution turns green
What does Na(s) react with? What is the rxn and observation?
Alcohols/phenols/carboxylic acids to give salt and hydrogen gas
redox rxn
effervescence
What does NaOH(aq) room temp. react with? What is the rxn and observation?
phenols/carboxylic acids to give salt and water
acid-base rxn
phenols/carboxylic acids insoluble in water will dissolve in NaOH(aq)
What does NaOH(aq) heat. react with? What is the rxn and observation?
halogenoalkanes: RX + OH- -> ROH + X-
NS rxn
distinguish diff HX with excess HNO3(aq) to resultant solution and add AgNO3 to ppt the silver halides
AgCl: white ppt AgBr: cream ppt AgI: yellow ppt
amides/nitriles to give ammonia gas and carboxylate salt
secondary amides carboxylate salt and amine
alkaline hydrolysis
ammonia gas liberated turns moist red limus paper blue
esters to give carboxylate salt and alcohol/phenoxide salt
alkaline hydrolysis
What does Na2CO3(aq) or NaHCO3(aq) react with? What is the rxn and observation?
carboxylic acids to give salt, water and carbon dioxide
acid-base rxn
effervescence
What does NaOH dissolved in ethanol heat react with? What is the rxn and observation?
halogenoalkane to remove halogen atom and hydrogen atom on adjacent carbons
elimination rxn
What does NH3 react with? What is the rxn and observation?
carboxylix acid to give CH3CO2-NH4+
acid-base rxn
acid chloride/bromide to give CH3CONH2+ HX
acid-base rxn
white fumes
What does NH3 dissolved in ethanol heat in sealed tube react with? What is the rxn and observation?
halogenoalkane to give CH3NH2 + HX
NS rxn
excess halogenoalkane may cause further substitution
What does PCl5/PCl3/SOCl2/PBr3 react with? What is the rxn and observation?
alcohols/carboxylic acids
substitution rxn
white fumes
PCl5 also reacts with water to form white fumes rxn must be in anhydrous environment
What does KCN or NaCN in ethanol heat react with? What is the rxn and observation?
halogenoalkanes to form CH3CH2CN + X-
NS rxn
carbon chain increased by one
What does Sn with conc. HCl heat react with? What is the rxn and observation?
nitrobenzenes to form phenylamine
reduction
NaOH is added to liberate phenylamine (neutralize C6H5NH3+)
What does NaBH4 react with? What is the rxn and observation?
aldehydes/ketones to give alcohol
reduction
CH3CHO + 2[H] -> CH3CH2OH
(CH3)2CHO + 2[H] -> (CH3)2CHOH
What does LiAlH4 in dry ether react with? What is the rxn and observation?
nitriles/aldehydes/ketones/carboxylic acids/esters/amides
reduction
LiAlH4 does not reduce alkenes
What does H2(g) with Ni catalyst high temp and pressure react with? What is the rxn and observation?
alkenes/aldehydes/ketones/nitriles
reduction
What is the confirmatory test for alkenes?
Br2(aq)
orange/brown solution decolourised
What is the confirmatory test for phenol and phenylamine?
Br2(aq)
orange/brown solution decolourised white ppt formed
What is the confirmatory test for aldehyde and ketones?
2,4-DNPH
orange ppt formed
hydrazone has well-defined melting point to identify aldehyde or ketone
What is the confirmatory test for aldehyde except benazldehyde?
fehling’s solution warm
reddish-brown ppt formed Cu2O
What is the confirmatory test for compounds with phenol functional group?
neutral FeCl3(aq) violet colouration
What is the confirmatory test for nitriles and amides?
NaOH(aq) heat
ammonia gas liberated turns moist red litmus paper blue
What is the confirmatory test for carboxylic acids?
Na2CO3 or NaHCO3
effervescence due to carbon dioxide produced
What does HBr(g)/ HCl(g) react with? What is rxn and observation?
alkenes
EA
