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A-Level Organic Chemistry AQA (Paper 2) > Organic Synthesis And Analysis > Flashcards

Organic Synthesis And Analysis Flashcards

1
Q

How do you synthesise a halogenoalkane from an alkane?

A

•X2 (halogen), UV light in free radical substitution.

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2
Q

How do you synthesise a halogenoalkane from an alkene?

A

•HX (halogen/hydrogen halide), room temperature in electrophilic addition.

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3
Q

How do you synthesise a primary/secondary/tertiary amine, their salts and quaternary ammonium salts from a halogenoalkane? (5)

A
  • Excess conc ammonia, heat/reflux, in a sealed container, ethanolic at a pressure in nucleophilic substitution:
  • Ammonia + halogenoalkane —> alkylammonium salt
  • Then nucleophilic addition-elimination of second ammonia molecule:
  • Alkylammonium salt ⇌ primary amine + ammonium salt
  • 2^y, 3^y amine and ammonium salt = excess halogenoalkane.
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4
Q

How do you synthesise a primary amine from a halogenoalkane? (4)

A
  • Excess conc ammonia, at a pressure, in a sealed container, dissolved in ethanol, heat in nucleophilic substitution:
  • Ammonia + halogenoalkane —> alkylammonium salt
  • Then nucleophilic addition-elimination of second ammonia molecule:
  • Alkylammonium salt ⇌ primary amine + ammonium salt
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5
Q

How do you synthesise a primary amine from a nitrile? (4)

A

•1). LiAlH4 in dry ether, dilute H2SO4 by reducing a nitrile (nucleophilic addition):
•Nitrile + 4[H] –(LiAlH4, H2SO4)–> primary alkane.
Or
•2). Reducing a nitrile using hydrogen gas with a metal catalyst e.g. platinum or nickel at a high temperature and pressure = catalytic hydrogenation:
•Nitrile + 2H2 –(nickel catalyst, high temp 200°C and pressure)–> primary alkane

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6
Q

How do you synthesise a nitrile from a halogenoalkane?

A

•KCN, ethanolic, heat/reflux in nucleophilic substitution.

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7
Q

How do you synthesise an alcohol from a halogenoalkane?

A

•Warm NaOH(aq), reflux in nucleophilic substitution.

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8
Q

How do you synthesise an alkene from a halogenoalkane?

A

•Conc KOH, ethanol, hot in an elimination reaction.

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9
Q

How do you synthesise a dibromoalkane from an alkene?

A

•Br2, room temperature in electrophilic addition (unsaturation test).

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10
Q

How do you synthesise an alkene from alcohol?

A

•Conc H2SO4, hot 180°C, elimination reaction/dehydration (removal of water).
OR
•Passing alcohol vapours over heated Al2O3 catalyst.

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11
Q

How do you synthesise an alcohol from an alkene? (2)

A

•1). H3PO4 catalyst, steam, 300ºC, 60 atm in hydration reaction, mechanism = electrophilic addition.
Or
•2). H2O, cold conc H2SO4 catalyst in electrophilic addition.

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12
Q

How do you synthesise an alcohol from an aldehyde/ketone? (2)

A
  • NaBH4 (aq) or dissolve in methanol then boiling water; dry ether, in reduction/nucleophilic addition:
  • Aldehyde/ketone + 2[H] —> alcohol
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13
Q

How do you synthesise a carboxylic acid from a primary alcohol? (2)

A
  • H^+/K2Cr2O7, H2SO4, reflux, in oxidation:

* Primary alcohol + [O] —> aldehyde + (+H2O) [O] —> carboxylic acid

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14
Q

How do you synthesise a carboxylic acid from an aldehyde? (2)

A
  • H^+/K2Cr2O7, H2SO4, reflux, in oxidation:

* Aldehyde + [O] —> carboxylic acid

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15
Q

How do you synthesise an alcohol and a carboxylic acid from an acyl chloride/acid anhydride?

A

•H2O, room temperature, in nucleophilic addition-elimination.

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16
Q

How do you synthesise a carboxylic acid from an ester? (2)

A

•1). Dilute H2SO4 catalyst, H2O, warm, in hydrolysis.
Or
•2). Dilute NaOH, warm, in hydrolysis.

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17
Q

How do you synthesise an aldehyde/ketone from a primary/secondary alcohol? (3)

A
  • H^+/K2Cr2O7, H2SO4, heat in distillation apparatus, in oxidation:
  • Primary alcohol + [O] —> aldehyde + H2O
  • Secondary alcohol + [O] –(reflux)–> ketone + H2O
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18
Q

How do you synthesise an ester from a carboxylic acid?

A

•Alcohol, conc H2SO4 catalyst, heat, in esterification/condensation (produces H2O).

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19
Q

How do you synthesise an ester from an acyl chloride/acid anhydride?

A

•Alcohol, room temperature, in nucleophilic addition-elimination.

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20
Q

How do you synthesise a primary amide from an acyl chloride/acid anhydride?

A

•NH3, room temperature, in nucleophilic addition-elimination.

21
Q

How do you synthesise an N-substituted amide from an acyl chloride/acid anhydride?

A

•Amine, room temperature, in nucleophilic addition-elimination.

22
Q

How do you synthesise a 2-hydroxynitrile from an aldehyde/ketone?

A

•KCN (aq), dilute H2SO4, room temperature, in reduction/nucleophilic addition.

23
Q

How do you synthesise nitrobenzene from benzene?

A

•Conc H2SO4, conc HNO3, below 55ºC (50°C) in nitration = electrophilic substitution.

24
Q

How do you synthesise a phenylketone from benzene?

A

•RCOCl, AlCl3 catalyst, reflux, non-aqueous environment = anhydrous, in acylation/electrophilic substitution.

25
Q

How do you synthesise an aromatic amine from nitrobenzene? (2)

A
  • Sn, conc HCl, reflux, then add NaOH in reduction:

* Nitrobenzene + 6[H] –1). tin, conc HCl reflux, 2). NaOH–> phenylamine.

26
Q

How do you synthesise a N-substituted phenylamide from a aromatic amine?

A

•RCOCl, room temperature in nucleophilic addition-elimination.

27
Q

How do you synthesise cyclic hexane from benzene?

A

•H2(g), nickel catalyst, 200°C in hydrogenation/reduction reaction.

28
Q

How do you synthesise an aromatic alcohol from an aromatic ketone?

A

•NaBH4(aq), dry ether in reduction/nucleophile addition reaction.

29
Q

How do you synthesise an alkyl hydrogensulfate from an alkene?

A

•Conc H2SO4, room temp in electrophilic addition.

30
Q

How do you synthesise an alcohol from an alkyl hydrogensulfate?

A

•Dilute and warm NaOH/H2O or dilute H2SO4 catalyst, warm in hydrolysis.

31
Q

How do you synthesise an alkane from an alkene?

A

•H2(g), nickel catalyst, 200°C in nucleophilic addition = reduction.

32
Q

How do you synthesise an alkene from an alkane?

A

•Thermal cracking - 1000°C, 70 atm.

33
Q

How do you synthesise an alcohol and salt from an ester?

A

•NaOH (aq), warm in saponification/ester hydrolysis.

34
Q

How are functional groups connected?

A

(See textbook page 475)

35
Q

What is the main oxidising agent used in organic chemistry?

A

•Potassium dichromate (VI), K2Cr2O7, acidified with dilute sulfuric acid.

36
Q

What will acidified potassium dichromate oxidise? (3)

A
  • Primary alcohols to aldehydes.
  • Aldehydes to carboxylic acids.
  • Secondary alcohols to ketones.
37
Q

What are the different reducing agents and their capabilities? (6)

A
  • 1). Sodium tetrahydridoborate (II), NaBH4.
  • Will reduce polar unsaturated groups e.g. C^𝛿+=O^𝛿- but not non-polar ones e.g. C^𝛿+=C^𝛿+ because it generates the nucleophile :H^- which attacks C^𝛿+, but it repelled by the electron rich C^𝛿+=C^𝛿+.
  • 2). Hydrogen with nickel catalyst, H2/Ni.
  • Reduces C=C, but not C=O.
  • 3). Tin and hydrochloric acid, Sn/H^+.
  • May reduce R-NO2 to R-NH2.
38
Q

What are drying agents? (2)

A
  • When alcohols are converted to alkenes by passing their vapours over heated aluminium oxide.
  • Or by acid-catalysed elimination reactions e.g. H2SO4.
39
Q

How do you test for alkenes? (2)

A
  • Shake with bromine water.

* +ive = red-brown goes colourless.

40
Q

How do you test for halogenoalkanes? (4)

A
  • 1). Add NaOH(aq) and warm.
  • 2). Acidify with HNO3.
  • 3). Add AgNO3(aq).
  • +ive = precipitate of AgX.
41
Q

How do you test for an alcohol? (3)

A
  • Add acidified K2Cr2O7 = [o] Cr 6+ ions get reduced to Cr^3+ ions
  • +ive = orange colour turns green with primary and secondary alcohols (also with aldehydes) they get oxidised to aldehydes and carboxylic acids.
  • Tertiary alcohol = no change.
42
Q

How do you test for an aldehyde? (3)

A

•Warm with Fehling’s solution, blue to brick-red precipitate.
Or
•Warm with Tollen’s solution (2Ag(NH3)2OH (aq)), forms silver mirror.
Or
•Add acidified K2Cr2O7, orange to green.

43
Q

How do you test for a carboxylic acid? (2)

A
  • Add NaHCO3(aq).

* +ive = bubbles observed as CO2(g) given off.

44
Q

If a compound is solid, what does it suggest?

A

•Long carbon chain/ionic bonding.

45
Q

If a compound is a liquid, what does it suggest?

A

•Medium length carbon chain or polar or hydrogen bonding.

46
Q

If a compound is a gas, what does it suggest?

A

•Short carbon chain bonding, little or no polarity.

47
Q

If a compound dissolves in water, what does it suggest?

A

•Polar bonds, other way around = non-polar.

48
Q

If a compound burns with a smoky flame, what does it suggest?

A

•High C : H ratio, possibly aromatic, other way round = non-aromatic.

A-Level Organic Chemistry AQA (Paper 2) (17 decks)

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