Organic synthesis Flashcards
(149 cards)
1
Q
A
2
Q
What is the order of priority when naming molecules
A
Cool Angry Elephants Act Awfully Naughty After Kicking All Angry Animals
Highest priority
Carboxylic acid
> Anhydride
> Ester
> Acyl chloride
> Amide
> Nitrile
> Aldehyde
> Ketone
> Alcohol
> Amine
Lowest priority
3
Q
What temperature are hydrocarbons heated to in a fractional distillation column
A
350 degrees C
4
Q
What are the conditions for thermal cracking
A
1000 degrees C
70atm
5
Q
What are the conditions for catalytic cracking
A
450 degrees C
Zeolite catalyst
Moderate pressure (150kPa)
6
Q
What is the name of the mechanism whereby hydroxide ions react with a halogenoalkane using an aqueous solvent
A
Nucleophilic substitution
7
Q
What are the conditions required for the substitution reaction of hydroxide ions with a halogenoalkane
A
Warm aqueous NaOH
Carried out under reflux
8
Q
What is formed when hydroxide ions react with a halogenoalkane using an aqueous solvent
A
An alcohol
9
Q
What is formed when halogenoalkanes react with cyanide ions
A
Nitriles
10
Q
What are the conditions required for the reaction of cyanide ions with a halogenoalkane
A
Warm ethanolic, aqueous potassium cyanide
Carried out under reflux
11
Q
What are the conditions required for the reaction between ammonia and a halogenoalkane when the desired product is an amine
A
Heat with concentrated ethanolic ammonia
Must have excess ammonia
12
Q
What is produced when ammonia reacts with a halogenoalkane
A
An amine and an ammonium ion
13
Q
What is the name of the mechanism where hydroxide ions react with a halogenoalkane using an ethanol solvent
A
Elimination
14
Q
What are the conditions required for the elimination reaction between hydroxide ions and a halogenoalkane
A
Hot ethanolic concentrated sodium hydroxide
Carried out under reflux
15
Q
When reacting NaOH with a halogenoalkane, when do we form an alcohol
A
When water is used as the solvent
16
Q
What occurs in the initiation stage of the formation of chlorine radicals which catalyse the breakdown of ozone
A
Sunlight (UV) breaks down the C-Cl bond in a CFC producing 2 radicals which react with ozone molecules
17
Q
What 2 equations occur in the propagation stage of the formation of chlorine radicals which catalyse the breakdown of ozone
A
1- Cl radical reacts with O3 to form a ClO radical intermediate and O2
2 - ClO radical reacts with more O3 to make O2 and a Cl radical (reformed so is a catalyst)
18
Q
What occurs in the termination stage of the formation of chlorine radicals which catalyse the breakdown of ozone
A
Two Cl radicals react to form Cl2
19
Q
Does a higher temperature encourage elimination or substitution for the reaction between OH- and halogenoalkanes
A
Higher temperatures encourage elimination
20
Q
Does a higher concentration of OH- encourage elimination or substitution for the reaction between OH- and halogenoalkanes
A
Higher concentrations favour elimination.
21
Q
What mechanism can alkenes undergo when they react with an electrophile
A
Electrophilic addition
22
Q
What is the test for alkenes
A
When we add bromine water, if alkenes are present, a colour change will occur from brown/orange to colourless
23
Q
What do we form when we add bromine to an alkene
A
A dibromoalkane
24
Q
By what mechanism does bromine react with an alkene
A
Electrophilic addition
25
What is formed when an alkene reacts with a hydrogen halide
Halogenoalkanes
26
What are the conditions for the reaction of bromine with an alkene
Room temperature (not in UV light)
27
What are the conditions for the reaction of hydrogen halides with an alkene
Room temperature
28
What is the role of sulfuric acid when reacting with an alkene
Used as a catalyst in making alcohol from an alkene
29
What do we form when we react sulfuric acid with an alkene
Alkyl hydrogen sulfate intermediates
And alcohol as product
30
What are the conditions for the reaction between an alkene and sulfuric acid
Cold, concentrated sulfuric acid
31
What can we add to an alkyl hydrogen sulfate to reform sulfuric acid, what is this process called
Cold water
Hydrolysis
32
What are the conditions required for the hydrolysis of an alkyl hydrogen sulfate
Add cold water to warm a warm alkyl hydrogen sulfate
33
How can we sustainably make an alkene from an alcohol
Dehydrate an alcohol which is produced via the fermentation of glucose from plants in the presence of an acid catalyst
34
What do we call the process of eliminating water from a molecule
Dehydration
35
How can we form an alcohol from an alkene
Hydrate the alkene in the presence of an acid catalyst
36
Give an equation for the dehydration of ethanol to produce an alkene
Must be done in warm conditions (under reflux) and in the presence of concentrated sulfuric acid
37
What is the mechanism by which the dehydration of alcohols to form an alkene occurs
Acid catalysed elimination
38
When we dehydrate an alcohol, the mixture is impure. What are the components of this impure mixture
Alkene
Alcohol
Water
Acid
39
How can we separate an impure mixture produced from the dehydration of an alcohol
Distillation
40
What can we do to further purify an impure mixture produced from the dehydration of an alcohol which has already been distilled
We can use a separation funnel to separate aqueous and organic layers
The addition of a drying agent ( to remove any H2O)
41
What are the 3 steps in producing cyclohexene from an alcohol
Distillation
Separation
Purification
42
What is the reagent and conditions required for the dehydration of an alcohol to form an alkene, and what is the name of the mechanism
Elimination
Reagent: Concentrated sulfuric acid
Conditions: Warm (under reflux)
43
What are the conditions required for the hydration of ethene to form ethanol
high temperature 300 °C
high pressure 70 atm
strong acidic catalyst of conc H3PO4
44
Outline and name the mechanism for the formation of ethanol via the hydration of ethene
Electrophilic Addition
45
What are the 2 ways of producing ethanol
Hydration of ethene (from crude oil)
Fermentation of glucose
46
What are the conditions for the fermentation of glucose
Yeast
Anaerobic conditions
Temperature of 30-40 degrees C
47
Write equations displaying how ethanol produced by fermentation is a carbon neutral process
48
What 3 things can alcohols be oxidised to form
Aldehydes
Ketones
Carboxylic acids
49
What is the conditions and reagent required for the oxidation of primary alcohols to produce a carboxylic acid
Reagent: potassium dichromate(VI) solution and dilute
sulfuric acid
Conditions: use an excess of dichromate, and heat
under reflux (can then distil to separate products)
50
What is the conditions and reagent required for the oxidation of secondary alcohols to produce a ketone
Reagent: potassium dichromate(VI) solution and dilute
sulfuric acid
Conditions: use an excess of dichromate, and heat
under reflux
51
What is the conditions required for the oxidation of primary alcohols to produce an aldehyde
Reagent: potassium dichromate(VI) solution and dilute
sulfuric acid
Conditions: Do not use an excess of dichromate, or heat
under reflux
52
What is the test for carboxylic acids
Addition of sodium carbonate. It will fizz and produce
carbon dioxide if a carboxylic acid is present
53
What 2 things can we use to distinguish between aldehydes and ketones
Fehling's solution
Tollens reagent
54
What is the role of both Fehling's solution and Tollens reagent reagent when distinguishing between aldehydes and ketones
They are oxidising agent
They oxidise aldehydes but not ketones
55
What is the formula for tollens reagent
(Ag(NH3)2)+
56
What is the test for alcohols
Acidified K2Cr2O7 goes from orange to green in OH-
57
What is the reagent and positive test result for primary and secondary alcohols
Reagent: acidified pottasium dichromate (K₂Cr₂O₇)
Primary and secondary alcohols are oxidised by K₂Cr₂O₇.
Will turn from orange to green (Cr₂O₇²⁻ to Cr³⁺)
58
What is the reagent and positive test result for a tertiary alcohol
Will remain orange on addition of acidified potassium dichromate
59
What is the reagent and positive test result for an aldehyde
Reagent: Fehling's solution (in hot water bath) - goes from a blue solution to a red precipitate in the presence of an aldehyde
or
Reagent: Tollens reagent (in hot water bath)- formation of a silver mirror in the presence of an aldehyde
60
What is the reagent and positive test result for a carboxylic acid
Write an equation for the positive test with CH3CO2H
Reagent: Add sodium carbonate
Effervescence of CO2 formed - can then bubble through limewater to test this
2CH3CO2H + Na2CO3 ---. 2CH3CO2Na + H2O + CO2
61
What is the reagent and positive test result for chloroalkanes
Reagent: Warm with silver nitrate
Slow formation of white precipitate AgCl
62
Write an equation for the reaction of CH3CHO with tollens. Write the practical steps to test it and what occurs
Tollens’ Reagent formed by mixing aqueous
ammonia and silver nitrate, which we heat gently in a water bath then add what were testing
Aldehydes are oxidised by tollens into a carboxylic acid, and silver ions are reduced to silver atoms (silver mirror)
CH3CHO + 2Ag+ + H2O ---> CH3COOH + 2Ag + 2H+
63
Write an equation for the reaction of CH3CHO with Fehlings. Write the practical steps to test it and what occurs
We heat gently in a water bath then add what we are testing
Aldehydes are oxidised by Fehling’s Solution
into a carboxylic acid. The copper (II) ions are reduced
to copper(I) oxide (blue to brick red)
CH3CHO + 2Cu2+ + 2H2O ----> CH3COOH + Cu2O + 4H+
64
Where is the fingerprint region in infrared spectrometry
Between 500cm-1 and 1500cm-1
65
What is the condition for optical isomerism to arise in organic compounds
The presence of a chiral carbon which gives rise to a non superimposable mirror image
66
How is a racemic mixture formed
The carbonyl group is planar
So there is an equal probability of a nucleophilic attack from either side
This leads to the formation of a racemic mixture
67
What does optical activity mean
Ability to rotate plane polarised light
68
What are the conditions for EZ isomerism to arise
C=C can’t rotate
Each carbon in double bond has 2 different groups attached
69
What are aldehydes oxidised into and what are the conditions and reagent for this reaction
Carboxylic acids
Reagent: potassium dichromate (VI) solution and
dilute sulphuric acid.
Conditions:
Heat under reflux
70
How do we make tollens
Add a few drops of NaOH to a solution of silver nitrate (forms a pale brown precipitate)
Add a few drops of dilute ammonia until the precipitate dissolves
This is tollens reagent
71
What are the conditions and positive test result for distinguishing between aldehydes and ketones using Fehling's
Conditions: heat gently
Observation: Aldehydes :Blue Cu 2+ ions in solution
change to a red precipitate of Cu2O. Ketones do
not react.
72
What do we use as a reducing agent when reducing aldehydes and ketones
NaBH4
Represented as [H]
Source of hydride (H-) ions
73
What is the name of the mechanism by which aldehydes and ketones are reduced using NaBH4
Nucleophilic addition
74
What are carbonyl compounds reduced to by CN- ions
Hydroxynitriles
75
What is the name of the mechanism by which carbonyl compounds are reduced to hydroxynitriles
Nucleophilic addition
76
What are the 2 methods of reducing a carbonyl compound to a hydroxynitrile. State the reagent and conditions for both
Method 1:
Reagent: HCN
Conditions: None
Method 2:
Reagent KCN
Conditions: Dilute H2SO4(aq) (Source of H+)
77
78
Outline 3 stages in how we can measure the melting point of a sample to test its purity
Put sample in suitable capillary in oil bath or melting point apparatus
Heat slowly to establish melting point range
Broad range of melting point indicates
presence of impurities
OR melting point agrees with/close to data book value
79
What are the conditions for the reaction between a carboxylic acid and an alcohol to form an ester
Concentrated H2SO4 catalyst
Warm conditions (reflux)
80
What is the general equation for the hydrolysis of an ester in acidic conditions
Ester + water <---> carboxylic acid + alcohol
81
What is the general equation for the hydrolysis of an ester in alkaline conditions
Ester + sodium hydroxide ----> carboxylate salt + alcohol
82
What are the conditions for the hydrolysis of an ester in acidic conditions
Dilute aqueous H2SO4 catalyst
Hot conditions (reflux)
83
What are the conditions for the hydrolysis of an ester in alkaline conditions
Aqueous NaOH
Reflux
84
How do we turn a carboxylate salt from the hydrolysis of an ester in alkaline conditions into a carboxylic acid
Add dilute HCl
85
What are the conditions for the reaction between a carboxylate salt and HCl to form a carboxylic acid
Warm carboxylate salt
Dilute HCl
86
What do we get when we react glycerol and fatty acids together
An ester
87
What do we get when we react NaOH with a fat(ester)
Glycerol & soap
88
What is the general equation for saponification
Fat + 3NaOH ---> Glycerol + 3 Carboxylate salt (soap)
89
What are the conditions for saponification (Base hydrolysis)
Reflux
Aqueous NaOH
(CONC when using to break proteins)
90
What is the general equation for transesterification
Fat + 3Methanol ---> glycerol + 3Biodiesel (methyl ester)
91
What are the conditions for transesterification
KOH catalyst
92
What is the general equation for when an acyl chloride reacts with water
Acyl chloride + water ---> carboxylic acid + HCl
RCOCl + H2O ---> RCOOH + HCl
93
What is the general equation for when an acyl chloride reacts with ammonia
Acyl chloride + ammonia ---> Amide + HCl
RCOCl + NH3---> RCONH2 + HCl
94
What is the general equation for when an acyl chloride reacts with an alcohol
Acyl chloride + alcohol ---> Ester + HCl
95
What is the general equation for when an acyl chloride reacts with a primary amine
Acyl chloride + primary amine ---> N-substituted amide + HCl
96
What is the general equation for when an acid anhydride reacts with a water
Acid anhydride + water --> 2carboxylic acid
(2 of the same carboxylic acid)
97
What is the general equation for when an acid anhydride reacts with ammonia
Acid anhydride + ammonia --> Amide + carboxylic acid
98
What is the general equation for when an acid anhydride reacts with an alcohol
Acid anhydride + alcohol ---> Ester + carboxylic acid
99
What is the general equation for when an acid anhydride reacts with a primary amine
Acid anhydride + primary amine ---> N-substituted amide + carboxylic acid
100
What are the 2 tests for distinguishing between an acyl chloride and an acid anhydride.
For each state the reagent, observation and equation
Test 1:
Reagent: H2O
Observation with acyl chloride: Steamy misty fumes due to HCl
Observation with acid anhydride: no visible change
Equation with acyl chloride: RCOCl + H2O --> RCOOH + HCl
Test 2:
Reagent: AgNO3(aq)
Observation with acyl chloride: White ppt due to AgCl
Observation with acid anhydride: no visible change
Equations with acyl chloride: RCOCl + H2O --> RCOOH + HCl
HCl ---> H+ + Cl-
Ag+ + Cl- ---> AgCl
101
How do we make aspirin
salicylic acid + ethanoic anhydride ---> aspirin + ethanoic acid
102
What is the most common form of drying agent (when we have a general organic sample and want to remove H2O)
Sulfates (Calcium sulfate most common)
103
What is saponification essentially
Base hydrolysis of an ester
104
What are the 2 electrophiles which can react with benzene in electrophilic substitution
Nitronium ion (NO2+)
Acylium ion (RCO+)
105
What is the name of the mechanism for the nitration of benzene
Electrophilic substitution
106
What is the name of the mechanism for the acylation of benzene
Electrophilic substitution
107
What are the 3 stages in either nitration or acylation of benzene
1- Generation of electrophile
2- Mechanism
3 - Regeneration of catalyst
108
What catalyst is used in the acylation of benzene?
AlCl3
109
What is the reagent, catalyst and conditions required for the acylation of benzene
Reagent: RCOCl
Catalyst: AlCl3
Conditions: Anhydrous conditions, reflux, 50 degrees C
110
What catalyst is used in the nitration of benzene?
CONC
H2SO4
111
What is the reagent, catalyst and conditions required for the nitration of benzene
Reagent: Concentrated HNO3
Catalyst: Concentrated H2SO4
Conditions: Room temperature and pressure
112
What is the name of the molecule produced from the nitration of benzene
Nitrobenzene
113
What is the general name of the molecule produced from the acylation of benzene
Phenylketone
114
What are the 2 parts to Buchner apparatus
Buchner flask
Buchner funnel
115
What are the 2 ways to make a primary aliphatic amine
1: Reacting a halogenoalkane in excess NH3
2: Reducing a nitrile
116
What are the reagent and conditions required for the amine nucleophilic substitution reactions
Reagent: Warm Concentrated ethanolic NH3
Conditions: High pressure & heat in a sealed container
117
What does using an excess of NH3 in the amine nucleophilic substitution reactions lead to
An excess of NH3 minimises further substitution
118
What does using an excess of halogenoalkanes in the amine nucleophilic substitution reactions lead to
Excess of halogenoalkanes favours further substitution
119
What are the conditions and reagent for method 1(using LiAlH4) of producing a primary aliphatic amine through the reduction of a nitrile
Reagent: LiAlH4
Condition: In dry ether
120
What are the conditions and reagent for method 2 (catalytic hydrogenation) of producing a primary aliphatic amine through the reduction of a nitrile
Catalytic hydrogenation
Reagent: H2
Conditions: 150 degrees C
Catalyst: Nickel catalyst
121
What are the 2 methods to prepare an aromatic amine (NITROBENZENE TO PHENYLAMINE)
NITROBENZENE TO PHENYLAMINE
Method 1: Using a reducing agent
Method 2: Catalytic hydrogenation
122
What are the 2 methods to prepare a primary aliphatic amine from the reduction of a nitrile
Method 1: Using Lithium aluminium hydride
Method 2: Catalytic hydrogenation
123
What are the reagent and conditions for method 1 (using a reducing agent) of preparing an aromatic amine in both a lab and industry
Lab:
Reagent: Concentrated HCl
Catalyst: Sn
Industry:
Reagent: Concentrated HCl
Catalyst: Fe
Both under reflux
124
125
126
What are the monomers of kevlar
Benzene-1,4-dioic acid
Benzene-1,4-diamine
127
What are the monomers of nylon-6,6
Hexane-1,6-dioc acid
Hexane-1,6-diamine
128
What are the monomers of terylene
Benzene-1,4-dioc acid
Ethane-1,2-diol
129
How do disulphide bonds arise
Thoil groups (-SH) can lose the H atom and the sulfur atoms can bond forming a disulphide (S-S) bond
130
What two factors affect the effectiveness of an inhibitor
Concentration of inhibitor
How strongly the inhibitor binds to the active site of an enzyme
131
What type of method is used when developing new drugs
Trial and error
Scientists will see which inhibitors work and refine the molecule to make it more efficient
132
What are the monomers of DNA
Nucleotides
133
What are the 3 components which make up a nucleotide
A phosphate
A sugar
A base
134
What are the reagent and conditions for acid hydrolysis
Reagent: Aqueous dilue H2SO4
Conditions: Reflux
135
Write how many H bonds form between A-T & C-G
Adenine (A) pairs with Thymine (T) → 2 hydrogen bonds
Guanine (G) pairs with Cytosine (C) → 3 hydrogen bonds
136
Colour code the bonds between A-T & C-G
137
What are the 2 solvents used in NMR
CDCl3
CCl4
138
Draw the structure of CDCl3
139
Draw the structure of CCl4
140
What are the components of the moving phase in TLC?
Solvent
## Footnote
The solvent carries the samples up the TLC plate.
141
What is the stationary phase in TLC made of?
Silica gel or alumina on aluminum, glass, or plastic
## Footnote
The stationary phase interacts with the compounds being separated.
142
What is another method to visualize TLC spots besides UV?
Using a stain or developing agent like ninhydrin
143
What is the moving phase in gas chromatography (GC)?
Carrier gas (e.g., He or N₂)
144
What is the stationary phase in GC?
Non-volatile liquid film on inert powder in a coiled tube
145
What is the stationary phase in column chromatography?
Silica or alumina powder
146
What is the moving phase in column chromatography?
Eluent (a pure solvent or mixture)
147
Generally, when is it dilute Vs conc H2SO4 as a condition
When H2SO4 is a catalyst it is conc, otherwise it tends to be dilue
(Apart from acid hydrolysis)
148
What are the conditions for base/acid hydrolysis of a peptide (or ester)
Base : Aqueous NaOH under reflux
Acid: Aqueous dilute H2SO4 under reflux
Concentrated acid/base for peptides
149
Why do amino acids separate on a TLC plate
(The 1 liner to remember)
Difference in the balance between solubility in the mobile phase and attraction to the stationary phase
