9 Alcohols Flashcards

1
Q

What is the functional group of aliphatic alcohols?

A

a hydroxyl group (-OH) bonded to an sp3-hybridized carbon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are ‘-enol’ compounds?

A

compounds with the hydroxyl group attached to an unsaturated (sp2) C=C carbon atom

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Draw out two examples of aliphatic alcohols.

A

see document

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Draw out an enol and a phenol.

A

see document

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are alcohols classified according to?

A

the environment of the OH group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does the chemical behaviour (e.g. oxidation and reaction mechanisms) of an alcohol depend on?

A

on the structural type of alcohol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

For alcohols 1-3 state:

a) the name of the alcohol
b) the classification of the alcohol

A

a)
1 - 1-butanol
2 - 2-butanol
3 - 2-methyl-propan-2-ol

b)
1 - primary alcohol
2 - secondary alcohol
3 - tertiary alcohol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

State the process of IUPAC naming alcohols.

A

select the longest chain of carbon atoms containing the -OH group
remove the ‘-e’ and add ‘-ol’ after the basic name
number the chain starting from the end nearer to the -OH group
the number is placed after the ‘-an’ and before the ‘-ol’ (e.g. butan-2-ol)
as in alkanes, prefix with alkyl substituents
side-chain positions are based on the number allocated to the -OH group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

State the process common naming of alcohols.

A

name the alkyl group bonded to oxygen followed by the word alcohol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

For alcohols 1-6 state:

a) the IUPAC name
b) the common name (i.e. ‘-yl alcohol’ and then primary = iso, secondary = sec and tertiary = tert)

A
a) IUPAC names:
1 - propan-1-ol/ 1-propanol
2 - propan-2-ol/ 2-propanol
3 - butan-1-ol/ n-propanol
4 - butan-1-ol/ sec-butanol
5 - 2-methyl-propan-1-ol
6 - 2-methyl-propan-2-ol/ tert-butanol
b) common names:
1 - propyl alcohol
2 - isopropyl alcohol
3 - butyl alcohol 
4 - sec-butyl alcohol 
5 - iso-butyl alcohol
6 - tert-butyl alcohol
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How are compounds containing more than one -OH groups named?

A

named as diols, triols, etc…

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

For compounds 1-3 (on document) with multiple -OH groups state:

a) the IUPAC name
b) the common name

A
a) 
1 - ethane-1,2-diol/1,2-ethanediol
2 - propane-1,2-diol/1,2-propanediol
3 - 1,2,3-propanetriol/propane-1,2,3-triol
b) 
1 - ethylene glycol
2 - propylene glycol
3 - glycerol/glycerine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What type of compounds are alcohols?

A

polar compounds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What type of boiling points do alcohols have and why?

A

much higher than comparable hydrocarbons and ethers

due to hydrogen bonding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Draw out a diagram showing hydrogen bonding between 4 methanol molecules including lone pairs.

A

see document

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Draw out the bonding between a model methanol molecule including the lone pairs.

A

see document

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How soluble are (small) alcohols and why?

A

lower (smaller) alcohols (and ethers) are water-soluble

due to hydrogen bonding with water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What does hydrogen bonding mean for the use of alcohols in terms of other organic molecules?

A

good solvents for a wide range of organic molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What do the boiling points of alcohols increase with?

A

increase with the number of carbon atoms/lenghth of carbon chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are the 3 properties of the ‘electron-rich’ and ‘nucleophilic’ oxygen atom in alcohols?

A
  • lone-pair donors (Lewis bases)
  • proton acceptors (Bronstead-Lowry bases)
  • nucleophilic (lone pair attacks electron-deficient centres)

(see document for this)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What can most alcohols not classed as but are able to act as?

A

most alcohols are not weak acids

but H⁺ can be removed by a strong base or reaction with a strong metal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What property do the electron-deficient C and H atoms in alcohols have?

A

they are attacked by electrophiles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

State how alcohols are synthesised by ‘hydration’ by ‘Markovnikov addition’ of alkenes, including:

a) reagents
b) conditions

(Hint: Markovnikov = major product)

A

a) H₂O and conc. H₂SO₄ (or another acid catalyst)

b) heat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

State how alcohols are chemically synthesised by ‘hydration’ by ‘Anti-Markovnikov’ addition of alkenes, including:
a) reagents

(Hint: anti-Markovnikov = minor product)

A

a) step 1: BH₃

step 2: + H₂O₂

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Give an example of a 'Markovnikov addition' reaction of prop-1-ene (draw out the molecules too).
(see document)
26
Give an example of a 'anti-Markovnikov addition' reaction of prop-1-ene (draw out the molecules too).
(see document)
27
Give an example of a 'hydration' reaction in the citric acid cycle (draw out the molecules too) and name the enzyme involved.
The step in beta-oxidation of fatty acids in mitochondria or peroxisome RCH₂CH(OH)CH₂COSCoA + H₂O → RCH₂CH=CHCOSCoA (Enzyme: enoyl-CoA Hydratase) R = CH₃, CH₃CH₂... etc... (see document for drawings)
28
State how alcohols are chemically synthesised by 'substitution of alkyl halides' including: a) reagents b) conditions c) the general reaction equation
a) NaOH, H₂O b) heat c) R-X + NaOH → R-OH + NaX
29
What do all organometallic reagents have?
a nucleophilic carbon
30
What is a 'Grignard reagent?' (Hint: Grind = being mixed, X = Cl, Br, etc...)
R⁺-MgX (where X = Br, Cl (halide))
31
What is 'Organolithium?' (Hint: R = by itself/organic/all natural)
R⁺-Li (lithium alkyl)
32
State how alcohols are chemically synthesised using carbonyls by 'addition of organometallic to aldehydes/ketones' in 2 steps including: the full reaction equation a) reagents b) conditions
R-C=O-R₂ + R₃-MgX → R(-R₂ )-C-R₃(-O-MgX) → R-R₂ -C-R₃(-OH) (see document for symbol equation) step 1: a) R₃-MgX b) N/A step 2: a) N/A b) H⁺/H₂O
33
State how alcohols are chemically synthesised using carbonyls by 'reduction of an aldehyde/ketone' including: the full reaction equation and: a) reagents (Hint: for 1 O atom 1 metal in the reducing agent)
R-C=O-R₂ → R-C(-OH)-R₂ a) NaBH₄
34
State how alcohols are chemically synthesised using carbonyls by 'reduction of a carboxylic acid/ester' including: a) reagents b) the second less significant product also made (Hint: for 2 O atoms 2 metals in the reducing agent)
R-C=OO-R₂ → R-C(-OH) + HO-R₂ a) LiAlH₄ c) R₂-OH (alcohol)
35
Give an example of a biological 'reduction of carbonyl' reaction in the citric acid cycle (draw out the molecules too) and name the enzyme involved.
Dihydroxyacetone → (S)-glycerol phosphate enzyme = NAD(P)H (see document for diagram)
36
What are 'mono-oxygenase' enzymes?
enzymes that incorporate one hydroxyl group into substrates in many metabolic pathways
37
Give an example where 'mono-oxygenases' are used in biosynthesis.
consists of 2 steps enzyme for step 1 = CYP450 end-product = cortisol (enzyme) (see document for structures)
38
Using an example, explain how 'drug metabolism' is used in biosynthesis.
tamoxifen → more active metabolite (CYP3A4, 2C9, 2D6) (see document for structures)
39
For each of the following compounds a-c (see document) draw the product if it reacts with: a) + aq. H₂SO₄ b) + NaBH₄ c) + LiAlH₄
a) pentan-2-ol b) N/A (no reaction as NaBH₄ is not strong enough to reduce an ester) c) pentan-1,5-diol
40
For the 3 ways that alcohols chemically react to produce alkyl halides, write out the full general reaction equations: (Hint: RX usually made + HX too sometimes) a) reaction with thionyl chloride b) reaction with HX (acids) c) reaction with phosphorus halides
a) ROH + S=OCl₂ → RCl + SO₂ + HCl b) ROH + HX → RX + H₂O c) ROH + PX5 → RX + POX₃ + HX 3ROH + PX₃ → 3RX + H₃PO₃
41
State the reagents for the two substeps of the reaction between alcohols and phosphorus halides.
step 1: S=OCl₂ | step 2: Sn2
42
Draw out the mechanism for the general reaction between an alcohol and a phosphorus halide. (include alkyl groups as R and curly arrows to represent the movement of electrons)
(see document for this)
43
State how alkenes can be chemically synthesised using dehydration including: a) reagents b) conditions
a) H₂SO₄ b) 180°C (heat) (see document for the diagram of ethene production)
44
State a biological example of 2-step alkene synthesis using dehydration, including: a) the final product b) enzymes
a) prephenate → 4-hydroxyphenylpyruvate → tyrosine (product) | b) dehydroquinate dehydratase
45
What is another name for reacting alcohols with carboxylic acids?
esterification
46
State the general reaction for chemical synthesis of an ester.
R-OH + R-C=O(OH) ⇌ R-C=OOR + H₂O
47
Give an example of biological esterification involving acetyltransferases/esterases.
glycerol-3-phosphate → 1-acylglycerol-3-phosphate (acetyltranferase) (RC=O(SCoA))
48
What type of reaction is 'ether synthesis?'
substitution
49
State how an ether can be chemically synthesised from alcohol in 2 steps using 'William ether synthesis.' a) reagent of the 2nd step
R-OH + Na → RO-Na⁺ → R-O-R' + NaX alcohol ether a) R'X
50
What is 'methylation' and what can SAM (S-Adenosyl methionine) do?
Adding a CH3 group to a molecule | It is not just a reaction of alcohols SAM can methylate C, N, S
51
Give an example of a biological ether production by methylation with SAM. Include: a) reagents b) the enzyme
see document for this a) S-adenosyl methionine b) methyl transferase
52
How can primary alcohols (i.e. RCH₂OH) be oxidised?
→ aldehyde → carboxylic acid | → RCHO → RCOOH
53
Give an example of biological oxidation of a primary alcohol. State the reagents for each step and draw out the structures.
ethanol → acetaldehyde → acetic acid reagent: Na₂Cr₂O7 (see document for this)
54
How can secondary alcohols (i.e. RCH₂OH) be oxidised?
secondary alcohol → ketone
55
Give an example of biological oxidation of a secondary alcohol. State the reagents for each step and draw out the structures.
isopropanol → acetone reagent: Na₂Cr₂O7/H⁺ (see document for this)
56
How can tertiary alcohols be oxidised?
they cannot be oxidised
57
Why can tertiary alcohols not be oxidised?
for oxidation to take place easily you must have two hydrogen atoms on adjacent C and O atoms possible in primary and secondary alcohols, but not in tertiary ones
58
For each of the alcohols (on the document) a-c state name and draw out the product.
a) Acetaldehyde b) Acetone c) No product
59
Write out the balanced equation for the partial oxidation of ethanol using [O] to represent the oxidising agent.
CH₃CH₂OH + [O] → CH₃CHO + H₂O | ethanol ethanal
60
Which conditions are required in the lab for primary oxidation of alcohols?
essential to distill off the aldehyde before it gets oxidised to the acid
61
Write out the balanced equation for the oxidation of ethanal using [O] to represent the oxidising agent.
CH₃CHO + 2[O] → CH₃COOH + H₂O | ethanal ethanoic acid
62
State the practical details to oxidide an alcohol to an aldehyde (and draw the apparatus involved).
the alcohol is dripped into a warm solution of acidified K₂Cr₂O7 aldehydes have low boiling points - no hydrogen bonding - they distill off immediately if
63
What would happen if a primary alcohol wasn't distilled off as soon as it is oxidised to an aldehyde?
it would be oxidised to the equivalent carboxylic acid
64
State the practical details to oxidise an alcohol into a carboxylic acid (and draw the apparatus involved).
So, to oxidise an alcohol straight to the acid, reflux the mixture
65
What colour do dichromate ions change to during the oxidation of primary alcohols?
from orange to green
66
For each of the following compounds state the intermolecular bonding to justify the boiling points: a) ethanol, C₂H5OH, 78°C b) ethanal, CH₃CHO, 23°C c) ethanoic acid, CH₃COOH, 118°C
a) hydrogen bonding b) dipole-dipole bonding c) hydrogen-bonding
67
Give using the example of ethanol the reaction equation for biological oxidation stating (and drawing) the cofactors involved.
NAD⁺ NAD⁺ ethanol ⇌ acetaldehyde ⇌ acetic acid NADH NADH Zn2+ (see document for strcutures of compunds and of NAD/NAD⁺)
68
Draw out the 3 pathways for the biological exmaples of oxidation of alcohols (ethanol, methanol and ethylene glycol). (Hint: first 2 = can-openers)
see document for this
69
State the hybridisation of oxygen atoms within an alcohol and use it to explain its domain geometry.
Two sp3 hybrid orbitals form sigma bonds to carbon and hydrogen The remaining two sp3 hybrid orbitals each contain an unshared pair of electrons Domain geometry about the hydroxyl oxygen atom approximately 109° - repulsion of lone pairs vs size of sidechains (see document for diagram of this answer)