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A–level Reagents and Conditions
Reaction of…
Alkane
CH4 + 2O2
Ü
CO2 + 2H2O
Ü
Ü
CH3Cl + HCl
CH3Br + HBr
Preparation of …
n/a
R&C Burn in excess oxygen.
Classification Oxidation
Alkane
CH4 + Cl2
CH4 + Br2
Halogenoalkane
R&C Mix excess alkane with chlorine or bromine in the presence of ultra-violet light.
Classification Homolytic substitution
Observation Halogen colour decolourised
Alkene
CH3CH=CH2 + H2
Ü
CH3CH2CH3
Alkane
CH3CHClCH2Cl
CH3CHBrCH2Br
Halogenoalkane
CH3CHBrCH3
Halogenoalkane
CH3CH(OH)CH2OH
Alcohol
R&C Mix with hydrogen over heated nickel catalyst.
Classification Reduction
Alkene
CH3CH=CH2 + Cl2
CH3CH=CH2 + Br2
Ü
Ü
R&C Mix with a solution of the halogen in hexane at room temperature
Classification Heterolytic electrophilic addition
Observation Halogen colour decolourised
Alkene
CH3CH=CH2 + HBr
Ü
R&C Mix with HBr gas at room temperature.
Classification Heterolytic electrophilic addition
Alkene
CH3CH=CH2 + [O] + H2O
Ü
R&C Mix with a cold solution of potassium manganate (VII) and sodium hydroxide.
Classification Oxidation
Observation Turns green (MnO4-) followed by a brown precipitate (of MnO2)
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Reaction of…
Alkene
nCH2=CH2
Ü
-(CH2-CH2)n- low density
Preparation of …
Polymer (LDPE)
-(CH2-CH2)n- high density
Polymer (HDPE)
R&C Heat at 250oC and 2000 atm (with a free radical initiator)
Classification Homolytic (Free radical) addition
Alkene
nCH2=CH2
Ü
R&C Heat at 50oC and 10 atm with a catalyst of titanium (IV) chloride and
triethylaluminium.
Classification Heterolytic electrophilic addition.
Alkene
nCH3CH=CH2
Ü
-(CH(CH3)-CH2)n-
Polymer
(Polypropene)
R&C Heat at 50oC and 10 atm with a catalyst of titanium (IV) chloride and
triethylaluminium.
Classification Heterolytic electrophilic addition.
Halogenoalkane
CH3CH2Br + NaOH
Ü
CH3CH2OH + NaBr
Alcohol
R&C Boil under reflux with dilute aqueous sodium hydroxide.
Classification Heterolytic nucleophilic substitution
Observation If acidify with HNO3(aq) and add AgNO3(aq), white, cream or yellow AgX ppte.
Halogenoalkane
CH3CH2Br + KCN
Ü
CH3CH2CN + KBr
Nitrile
R&C Boil under reflux with a solution of potassium cyanide in aqueous ethanol.
Classification Heterolytic nucleophilic substitution
Halogenoalkane
CH3CH2Br + 2NH3
Ü
CH3CH2NH2 + NH4Br
Amine
R&C Heat in a sealed tube with an excess of concentrated ammonia in ethanol.
Classification Heterolytic nucleophilic substitution
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Reaction of…
Halogenoalkane
CH3CH2Br + KOH
CH3CHBrCH2CH3 + KOH
Ü
Ü
CH2=CH2 + H2O + KBr
CH3CH=CHCH3 + H2O + KBr
(and some CH3CH2CH=CH2)
Preparation of …
Alkene
R&C Boil under reflux with concentrated potassium hydroxide in ethanol.
Classification Elimination
Alcohol (1o)
CH3CH2OH + [O]
Ü
CH3CHO + H2O
Aldehyde
R&C Add a solution of potassium dichromate (VI) in dilute sulphuric acid to the hot
alcohol and allow the aldehyde to distil off.
Classification Oxidation
Observation Orange dichromate solution (Cr2O72-) turns green (Cr3+)
Alcohol (1o)
CH3CH2OH + 2[O]
Ü
CH3CO2H + H2O
Carboxylic acid
R&C Boil under reflux with a solution of potassium dichromate (VI) in dilute sulphuric
acid.
Classification Oxidation
Observation Orange dichromate solution (Cr2O72-) turns green (Cr3+)
Alcohol (2o)
CH3CH(OH)CH3 + [O]
Ü
CH3COCH3 + H2O
Ketone
R&C Boil under reflux with a solution of potassium dichromate (VI) in dilute sulphuric
acid.
Classification Oxidation
Observation Orange dichromate solution (Cr2O72-) turns green (Cr3+)
Alcohol
CH3CH2OH – H2O
Ü
CH2=CH2
Alkene
R&C Heat at 170oC with excess concentrated sulphuric acid.
Classification Dehydration
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Reaction of…
Alcohol
CH3CH2OH + PCl5
Ü
CH3CH2Cl + POCl3+ HCl
Preparation of …
Halogenoalkane
(chloro)
R&C Add PCl5 to the anhydrous alcohol at room temperature.
Classification Substitution
Observation Steamy fumes (HCl) which turn damp blue litmus paper red and give a dense white
smoke (NH4Cl) with an ammonia bottle stopper.
Alcohol
CH3CH2OH + HBr
Ü
CH3CH2Br + H2O
Halogenoalkane
(bromo)
R&C Add the alcohol mixed with concentrated sulphuric acid to solid sodium bromide at
room temperature.
Classification Substitution
Alcohol
3CH3CH2OH + PI3
Ü
3CH3CH2I + H3PO3 Halogenoalkane (iodo)
R&C Add the alcohol to a mixture of moist red phosphorous and iodine at room
temperature.
Classification Substitution
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The reactions on this and the previous pages are required for AS. The following pages are for A2 only.
Reaction of…
Halogenoalkane
Ü
CH3CH2Br + Mg
CH3CH2-MgBr
R&C Warm under reflux with magnesium turnings in a dry ether solvent and a trace of
iodine.
Classification Insertion
Preparation of …
Grignard reagent
Ü
Grignard reagent
CH3CH2-MgBr + HCHO + HCl
CH3CH2CH2OH + MgBrCl
R&C Bubble methanal through a solution of the Grignard reagent in dry ether at room
temperature, followed by acidification with dilute HCl.
Classification Heterolytic Nucleophilic addition
Alcohol (1o)
Grignard reagent
CH3CH2-MgBr + CH3CHO + HCl Ü
CH3CH2CH(OH)CH3 + MgClBr
R&C Mix an aldehyde with a solution of the Grignard reagent in dry ether at room
temperature, followed by acidification with dilute HCl.
Classification Heterolytic Nucleophilic addition
Alcohol (2o)
Grignard reagent
CH3CH2-MgBr + (CH3)2CO + HCl Ü
CH3CH2C(OH)(CH3)CH3 + MgClBr
R&C Mix a ketone with a solution of the Grignard reagent in dry ether at room
temperature, followed by acidification with dilute HCl.
Classification Heterolytic Nucleophilic addition
Alcohol (3o)
Ü
Grignard reagent
CH3CH2-MgBr + CO2 + HCl
CH3CH2CO2H + MgBrCl
R&C Add solid carbon dioxide (dry ice) to a solution of the Grignard reagent in dry ether
at room temperature (or bubble CO2 gas through a cooled solution), followed by
acidification with dilute HCl.
Classification Heterolytic Nucleophilic addition
Carboxylic acid
Ü
CH3CO2H + CH3CH2OH
CH3CO2CH2CH3 + H2O
R&C Heat anhydrous reactants under reflux with a few drops of concentrated sulphuric
acid.
Classification Heterolytic nucleophilic addition (followed by elimination).
Ester
Ü
CH3CO2H + 4[H]
CH3CH2OH + H2O
R&C Mix with a solution of lithium aluminium hydride (LiAlH4) in dry ether at room
temperature, followed by acidification with dilute HCl.
Classification Reduction
Alcohol (1o)
Carboxylic acid
Carboxylic acid
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Reaction of…
Carboxylic acid
Ü
CH3CO2H + PCl5
CH3COCl + POCl3 + HCl
R&C Carefully add phosphorous pentachloride at room temperature under anhydrous
conditions.
Classification Heterolytic nucleophilic substitution
Observation Steamy fumes (of HCl) given off.
Ü
2CH3CO2H + Na2CO3
2CH3CO2Na + CO2 + H2O
R&C Add sodium carbonate either as a solid or aqueous solution with care (CO2 will be
given off).
Classification Acid-base
Observation Bubbling of effervescence of a colourless gas evolved (CO2) which turns lime water
milky Ca(OH)2(aq) + CO2(g) Ü CaCO3(s) + H2O(l)
Carboxylic acid
Ester
↔
CH3CO2CH2CH3 + H2O
R&C Heat under reflux with dilute sulphuric acid.
Classification Hydrolysis
Ester
Ü
CH3CO2CH2CH3 + NaOH
R&C Heat under reflux with aqueous sodium hydroxide.
Classification Hydrolysis
Preparation of …
Acyl chloride
Carboxylate salt
CH3CO2H + CH3CH2OH
Alcohol and
carboxylic acid
CH3CO2Na + CH3CH2OH
Alcohol and
carboxylic acid
Ü
CH3CHO + [O]
CH3CO2H
R&C Heat under reflux with a solution of sodium dichromate (VI) acidified with dilute
sulphuric acid.
Classification Oxidation
Observation Orange solution (Cr2O72-) turns green (Cr3+).
Carboxylic acid
Ü
CH3CHO + [O] + NH3
R&C Warm carefully with a solution of silver nitrate in dilute ammonia.
Classification Oxidation
Observation Silver mirror precipitates on the test tube wall.
CH3CO2NH4
Carboxylate salt
CH3CO2Na + H2O
Carboxylate salt
Aldehyde
Aldehyde
Ü
CH3CO2H + [O] + NaOH
R&C Boil with Fehling’s solution.
Classification Oxidation
Observation Brick red precipitate obtained from deep blue solution.
Aldehyde
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Reaction of…
Carbonyl
Ü
RCOR’ + HCN
RCH(OH)CN
R&C Heat under reflux with a mixture of potassium cyanide and dilute sulphuric acid, or
with bubble HCN through a mixture of the carbonyl and a trace of NaOH.
Classification Heterolytic nucleophilic addition
Preparation of …
Hydroxynitrile
Ü
CH3CHO + 2[H]
CH3CH2OH
R&C Mix with a solution of lithium aluminium hydride in dry ether or sodium
borohydride in water at room temperature, followed by acidification with dilute
hydrochloric acid.
Classification Reduction
Alcohol (1o)
Ü
CH3COCH3 + 2[H]
CH3CH(OH)CH3
R&C Mix with a solution of lithium aluminium hydride in dry ether or sodium
borohydride in water at room temperature, followed by acidification with dilute
hydrochloric acid.
Classification Reduction
Alcohol (2o)
Ü
RCOR’ + H2N-NH-C6H4(NO2)2
RR’C=N-NH- C6H4(NO2)2 + H2O
Add a solution of 2,4-dinitrophenyhydrazine and cool.
Heterolytic nucleophilic addition followed by elimination (i.e. condensation)
Orange crystals precipitated.
n/a
Ü
Methyl carbonyls or
RCOCH3 + 3I2 + 4NaOH
RCO2Na + CHI3 + 3NaI + 3H2O
the corresponding
Ü
alcohols.
RCH(OH)CH3 + 4I2 + 6NaOH
RCO2Na + CHI3 + 5NaI + 5H2O
R&C Mix with an aqueous solution of iodine and sodium hydroxide (or KI and NaOCl), if
necessary heat then cool or allow to stand.
Classification Oxidation
Observation Yellow precipitate of triiodomethane (iodoform, CHI3) formed.
Carboxylate salt
Aldehyde
Aldehyde
Aldehyde or ketone
R&C
Classification
Observation
Ü
CH3COCl + H2O
R&C Add water to the acid chloride with care.
Classification Heterolytic nucleophilic addition followed by elimination
Observation Steamy fumes of HCl given off.
Acid chloride
CH3CO2H + HCl
Carboxylic acid.
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Reaction of…
Acid chloride
Ü
CH3COCl + CH3CH2OH
CH3CO2CH2CH3 + HCl
R&C Start cold then heat under reflux with ethanol under anhydrous conditions.
Classification Heterolytic nucleophilic substitution
Observation Steamy fumes of HCl given off, characteristic smell of ester, e.g. fruity.
Preparation of …
Ester
Ü
CH3COCl + 2NH3
CH3CONH2 + NH4Cl
R&C Start cold then heat under reflux with concentrated ammonia solution.
Classification Heterolytic nucleophilic substitution
Amide
Ü
CH3COCl + CH3CH2NH2
CH3CONHCH2CH3 + HCl
R&C Start cold then heat under reflux with amine, under anhydrous conditions.
Classification Heterolytic nucleophilic substitution
N-substituted amide
Ü
CH3CH2NH2 + HCl(aq)
CH3CH2NH3+Cl-(aq)
R&C Add to dilute strong acid such as hydrochloric or sulphuric acid.
Classification Acid-base
Observation Insoluble amines such as phenylamine ‘dissolve’ as the product is ionic.
Ammonium salt
Ü
CH3CH2NH2 + CH3COCl
CH3CONHCH2CH3 + HCl
R&C Start cold then heat under reflux with ethanoyl chloride, under anhydrous
conditions.
Classification Heterolytic nucleophilic substitution
N-substituted amide
Acid chloride
Acid chloride
Amine (1o)
Amine(1o)
Nitrile
Ü
CH3CH2CN + H+ + 2H2O
R&C Boil under reflux with dilute sulphuric acid.
Classification Hydrolysis
Nitrile
Ü
CH3CH2CN + OH- + H2O
R&C Boil under reflux with dilute sodium hydroxide.
Classification Hydrolysis
Nitrile
CH3CH2CO2H + NH4+
Carboxylic acid
CH3CH2CO2- + NH3
Carboxylate salt
Ü
CH3CH2CN + 4[H]
CH3CH2CH2NH2
R&C Mix with a solution of lithium aluminium hydride in dry ether at room temperature,
followed by acidification with dilute hydrochloric acid.
Classification Reduction
Amine (1o)
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Reaction of…
Amide
Ü
CH3CONH2 – H2O
R&C Warm with phosphorous pentoxide and allow the nitrile product to distil.
Classification Dehydration
Amide
CH3CN
Ü
CH3CONH2 + Br2 + 4NaOH
CH3NH2 + Na2CO3 + 2NaBr + 2H2O
R&C Add liquid bromine (not a solution) to the amide at room temperature then add
concentrated aqueous sodium hydroxide solution and warm.
Classification Substitution followed by rearrangement and elimination (also redox).
Preparation of …
Nitrile
Amine (1o)
Ü
RCH(NH3+)CO2- + H+
R&C Add aqueous hydrochloric acid solution.
Classification Acid-base
RCH(NH3+)CO2H
n/a
Ü
RCH(NH3+)CO2- + OHR&C Add aqueous sodium hydroxide solution.
Classification Acid-base
RCH(NH2)CO2-
n/a
Ü
C6H6 + HNO3
C6H5NO2+ H2O
R&C Add benzene slowly and with care to a cooled mixture of concentrated nitric and
sulphuric acids, then warm to 55oC under reflux
Classification Heterolytic electrophilic substitution.
nitrobenzene
Ü
C6H6 + Br2
C6H5Br + HBr
R&C Add bromine in small amounts to benzene and iron under reflux under anhydrous
conditions, warm if necessary.
Classification Heterolytic electrophilic substitution.
bromobenzene
Ü
C6H6 + Cl2
C6H5Cl + HCl
R&C Bubble chlorine through a solution of AlCl3 in benzene under reflux under
anhydrous conditions, warm if necessary.
Classification Heterolytic electrophilic substitution.
chlorobenzene
Amino acid
Amino acid
Benzene
Benzene
Benzene
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Reaction of…
Benzene
Ü
C6H6 + CH3CH2Cl
C6H5CH2CH3 + HCl
R&C Mix haloalkane (bubble through or dissolve) with a solution of AlCl3 in benzene,
under anhydrous conditions, under reflux.
Classification Heterolytic electrophilic substitution.
Preparation of …
alkyl benzene
Ü
C6H6 + CH3COCl
C6H5COCH3 + HCl
R&C Dissolve acyl chloride in a solution of AlCl3 in benzene, under anhydrous
conditions, under reflux.
Classification Heterolytic electrophilic substitution.
acyl benzene
Ü
C6H5CH2CH3 +6[O] + OHC6H5CO2- + CO2 + 3H2O
R&C Prolonged heat under reflux (2-3 hours) with a solution of potassium manganate
(VII) and sodium hydroxide.
Classification Oxidation
Observation *all side chains in which carbon is directly linked to the benzene ring are oxidised to
sodium benzoate, regardless of the original length of the side chain.
Benzoate salt
Phenol
Ü
C6H5OH(s) + NaOH(aq)
C6H5O-Na+(aq) + H2O(l)
R&C Add to dilute aqueous sodium hydroxide solution at room temperature.
Classification Acid-base.
Phenoxide salt
Phenol
Ü
C6H5OH + 3Br2
C6H2Br3OH + 3HBr
R&C Shake with bromine water at room temperature.
Classification Heterolytic electrophilic substitution.
Red-brown bromine water is decolourised and a white precipitate of 2,4,6tribromophenol.
tri-bromo phenol
Phenol
Ü
C6H5OH + NaOH + CH3COCl
CH3CO2C6H5 + NaCl
R&C Shake a solution of the phenol in aqueous sodium hydroxide with the acyl chloride
in excess.
Classification Heterolytic nucleophilic substitution
Ester
Benzene
Ethyl benzene*
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Reaction of…
Phenylamine
Ü
C6H5NH2 + HNO2 + H
C6H5N2 + 2H2O
o
R&C Add dilute hydrochloric acid to phenylamine and cool to 5 C. Add cooled sodium
nitrite solution in parts, keeping the temperature between 0oC and 5oC.
Classification Diazotisation
Observation Pale straw coloured solution formed.
+
+
Preparation of …
Diazonium ion.
Ü
C6H5N2+Cl- + C6H5O-Na+
C6H5-N=N-C6H5OH + Na+ClR&C A solution of phenol* dissolved in sodium hydroxide solution
Classification Coupling (also Heterolytic electrophilic substitution).
Yellow precipitate of the azo dye.
Observation *if 2-napthol is used the precipitate is red.
Azo dye
Ü
C6H5N2+Cl- + H2O
C6H5OH + N2 + H+ + ClR&C This reaction occurs on warming an aqueous solution of the diazonium ion. If a high
yield is required, the mixture must be steam distilled. If not, phenol formed by
decomposition will react with diazonium ions that have not yet been decomposed to
from an azo dye.
Classification Hydrolysis, also heterolytic nucleophilic substitution.
Observation Bubbling or effervescence of a colourless gas (N2) evolved, and a brightly coloured
precipitate.
Phenol
Ü
C6H5NO2 + 3Sn2+ + 6H+
C6H5NH2 + 3Sn4+ + 2H2O
R&C Heat under reflux with tin and concentrated hydrochloric acid, cool and add excess
aqueous sodium hydroxide solution (as C6H5NH3+Cl- formed initially).
Classification Reduction
Phenylamine
Diazonium ion
Diazonium ion
Nitrobenzene
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