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phenol

weak acid

stronger acid than alcohol or water

preparation:

1. NaNO₂ + HCl —> HNO₂ + NaCl (done in lower than 10⁰C)

2. phenylamine + HNO₂ + HCl —> benzene diazonium chloride + H₂O

3. benzene diazonium chloride + H₂O heated to give phenol, N₂, and HCl

delocalisation of electron reduces the charge density of the ion and hence stabilises the phenoxide ion

readily undergoes electrophilic substitution

reacts with alkali to form salt and water

reacts vigorously with metals to form salt and hydrogen gas

coupling reaction (2nd part of diazotisation) —> react with benzene diazonium to form azo dye and HCl in the presence of NaOH

halogenation

nitration

naphthols

two types: 1-naphthol and 2-naphthol

reacts with alkali to form salt and water

reacts vigorously with metals to form salt and hydrogen gas

halogenation

nitration

for 2-naphthol, the substituted atom/molecule goes between the OH and the ring, no substitution in position 4 will occur as it would be too cluttered

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In the lecture i learnt about how to prepare  phenol and all its reactions.
These reactions include- Electrophilic substitution: halogenation and nitration
I also learnt about naphthol and that it can react with sodium and sodium hydroxide. 1-Naphthol and 2-naphthol also undergoes reaction with bromine water and also dilute nitric acid. The positions where electrophilic substitution differs between 1-naphthol and 2-naphthol.

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the lecture focused on phenol. I learned about its reactions, properties, possible reagents, conditions, and how to prepare it. I learned about 2,4,6 and 1,3,5 placement depending on the species being substituted in. there was also naphthol, that had a double benzene ring structure and hence different rules for substitution and species placement

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Phenol

C6H5OH

Crystalline solid that melts at 43 °C

Mp is high for an aryl compound because of hydrogen bonding

The large non polar benzene ring disrupts the hydrogen bonding with water making it only slightly soluble in water

Weakly acidic

Position lies to the left-hand side

Phenol still stronger acid than water or an alcohol

Preparation of phenol

diazitisation, which is the reaction for dyes

phenylamine, which is important in synthesis of dyes

Phenol to Phenoxide

C6H5OH ⇌ C6H5O-  + H-

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phenol is a weak acid

reacts with alkali to form salt( sodium phenoxide and water)

reacts vigorously with sodium metal to form hydrogen gas and sodium phenoxide

preparation of phenol

diazitisation- reaction for dyes

phenylamine is a benzene, which is important in synthesis of dyes

steps:

prepare hno2 by using nano2 + hcl = hno2 + nacl (keep it under 10 degrees)

phenylamine + hno2 (nitrous acid/ nitric(III) acid

need to prepare nitrous acid because it is unstable, so prepare it by using nano2 + hcl

need to keep under 10 degrees

second step: (producing phenol)

n2+ cl- add with h20 = (heat) = phenol + n2 + hcl

coupling reaction

diazonium ions reacts with alkaline solution of phenol

positive diazonium as electrophile

phenol to phenoxide

c6h5oh = c6h5o-  + h-

negative charge of lone pair of electron have the tendency to overlap with the pi bonding.

they will be equally shared so less density

which will form a forward reaction, thus forming more h+

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I learned about the formula of phenol and its properties, how it is prepared and what reactions it has. I learned that for phenol different species, depending on whether they are electron-withdrawing or donating will go into different positions in the phenol. I also learned about phenol, and that it has similar reactions to phenol.

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Phenol

-C6H5OH
-Crystalline solid, melting point is 43 degree
-Mp is high for aryl due to the hydrogen bond
-Only slightly soluble in water due to the large non-polar benzene ring
-Weak acid

Preparation of phenol

-phenylamine + HNO2
-kept under 10 degree celcius
-diazotization
-N2 is used to prevent decomposition

Reactions of Phenol

-with alkali to form salt and water
-with sodium metal to form hydrogen gas and sodium phenoxide
-electrophilic substitution with halogen
-white precipitation
-electrophilic substitution of phenol nitration

Napthol
-Reaction with
-Na
-1,napthol with Br2
-2,napthol with Br2
-displaces between OH and the other benzene ring
-1,napthol with HNO3
-2,napthol with HNO3
-NO2 displaces between OH and the other benzene ring

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Properties of phenol (C6H5OH)

A crystalline solid that melts at 43°C

Melting point is high for an aryl compound because of hydrogen bonding

The large non polar benzene ring disrupts the hydrogen bonding with water making it only slightly soluble in water

Weakly acidic

Preparation of phenol

NaNO2 + HCI -> HNO2 + NaCI

Kept below 10°C to prevent decomposition to N2

Phenylamine + HNO2 +HCI -> benzenediazonium
chloride + water

Benzenediazonium chloride (acts as electrophile) is heated with H2O, forming phenol + HCI + N2

Phenoxide ion vs ethoxide ion

Reactions of phenol

React w alkali to form salt

React w Na to form sodium phenoxide

Diazotisation

Electrophilic substitutions (halogenations and nitration)

Naphthol and its reactions

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- properties of benzene
- sp2 hybrid
- trigonal planar
- weak acid

- phenol
- preparation
- reaction with water and sodium
- substitution with halogen and nitrile
- phenoxide ion
- diazotization

- naphthol
- reaction with Na/NaOH/B2/HNO3

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- Phenyl C6H5
- Benzene C6H6

Phenol Properties
- Phenol C6H4OH
- Melting point 43°C (high due to hydrogen bonding)
- slightly soluble (because non benzene ring)
- Weak acid (phenol<water<alcohol)
- can produce phenoxide

Phenol Reactions
- Friedel Crafts
- Alkylation (with alkyl groups)
- Acylation (with acyl groups)
- NaOH
- Nitration
- Diazotisation
- Electrophilic Substitution (halogenation, nitration)
- 1-naphthols (reactants bonded to 2, 4 atoms)
- 2-naphthols (reactants bonded to 4 because 2 is for hydroxide group)
- naphthol graphs

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Phenol

C6H5OH

Crystalline solid that melts at 43 degree celcius

Phenol is not soluble in water because the non polar of the benzene ring disrupt the hydrogen bonding with water.

Phenol is weakly acidic so they are going to be partially dissociating in water

Larger Ka means that the acid will dissociate more

Preparation of phenol

diazotisation

reaction that we are going to prepare for dye

Phenylamine is important in synthesis of dyes

NH2 is gained when NaNO2 is reacted with dilute HCl (reaction must be at 10 degree Celsius)

Phenylamine will react with HNO2+HCl = benzenediazonium chlorine + water

Benzenediazonium salt heat with water will get phenol + nitrogen + hydrochloric acid

Phenoxide ion has its negative charge spread all over the whole ion as one of the lone pairs on the oxygen atom overlaps with the pi bonding system in the benzene ring

The negative charge will have less density in the phenoxide ion and it will not join together with hydrogen

Phenoxide ion is more stable compared to phenol

Reactions of phenol

phenol reacts with sodium hydroxide to become sodium Phenoxide and water

Phenol reacts vigorously with sodium metal to form hydrogen gas and sodium phenoxide

Ethanol is not a very good weak acid so it is not able to react with sodium metal

will undergo all the reactions a weak acid supposed to undergo

Coupling reaction: one benzene ring reacts with another benzene ring

OH will activate position number 4 in coupling reaction because it will give more space

Hydrogen will be removed in coupling reaction

Electrophilic substitution of phenols halogenation

react with bromine water but albr3 is not needed

phenol reacts more readily with electrophile because the OH will donate electron to the benzene ring

Phenol is very reactive so they will go straight to the last reaction directly

Electrophilic substitution of phenols nitration

room temperature and dilute nitric acid

55 degree Celsius

Naphthol

Naphthol has two benzene rings

Naphthol + NaOH

Naphthol + Na

1-Naphthol + Br2

2-Naphthol + Br2

1-Naphthol + HNO3

2-Naphthol + HNO3

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I learned about:

-Phenol
-C6H5OH
-It is a crystalline solid, which melts at 43 degree Celsius
- It has high MP due to hydrogen bond
- It is slightly soluble as it has non polar benzene ring
- It is weakly acidic
- It forms an acidic reaction with Na and NaOH
- Diazotization with diazonium ion by adding phenulamine with HNO2
-Electrophilic substitution with bromine water in position 2,4,6
-Electrophilic substitution with nitric acid in position 1,3,5

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PHENOL
• C6H5OH
• A crystalline solid that melts at 43 oC
• Melting point is high for an aryl compound because of hydrogen bonding
• The large non polar benzene ring disrupts the hydrogen bonding with water making it only slightly soluble in water
• Weakly acidic
• Position lies to the left-hand side
• Phenol is still stronger acid than water or alcohol

Preperation of Phenol
NaNO2 + HCL -> HNO2 + NaCl
Phenylamine + HNO2 + HCL -> Benzenediazonium chloride + H2O
Benzenediazonium chloride heated with H2O -> C6H5OH + HCL + N2

Phenol is a weak acid, and has the same reactions with NaOH as with normal acids. H2O is produced as a byproduct and Na bonds with the O atom attached to benzene ring.

When Phenol reacts with bromine water, no catalyst is needed and is done under mild conditions. The Br molecules will then be substituted to all 2, 4, 6 positions of the phenol. The bromine water is decolourized and a white precipitate is formed.

Phenol reacts to nitric acid differently depending on its concentration.
With dilute nitric acid, a mixture of 2-nitrophenol and 4-nitrophenol is formed.
With concentrated nitric acid, more nitro groups substitute around the ring forming 2,4,6 - nitrophenol.

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https://sites.google.com/view/fredericchemistry/chapter-24-benzene-and-its-compounds

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Journey of Chemistry - Chapter 24: Benzene and its compounds

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We learnt about:
Properties of phenol
- Melts at 43 C, which is considered high due to the hydrogen bonding.
- Weakly acidic

Reactions of phenol
- Usual acidic reaction with Na and NaOH
- Diazotization with diazonium ion (prepared by adding phenylamine with HNO2)
- Electrophilic substitution with bromine water (2, 4, 6 pos)
- Electrophilic substitution with nitric acid (dilute adds 1, conc. adds 3)

https://sites.google.com/view/christopherchemistry/a2-chemistry/chapter-benzene-and-its-compounds

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For most reactions, electrophiles are attracted to the electron ring in benzene, due to the high density of electrons. So most reactions with benzene are electrophilic substitution.

Substitution with Halogens

Bromine is polarized by an anhydrous FeBr ₃ catalyst at room tem perature, forming Br⁺ and FeBr ₄⁻. The Br⁺ wi ll receive a pair of electrons from the benzene electron ring, forming an intermediate atom where one of the carbon atoms is bonded with H and Br. The ring is broken. Then, the H atom will donate its pair of electrons to the ring, making the ring complete, and H ⁺ will bond with a Br ⁻ f rom the catalyst.

A similar mechanism works with Cl, but anhydrous AlCl ₃ can also be a catalyst.

For catalysts involving halogens with this mechanism, the catalyst need to also have the same halogen. For example: FeBr ₃ with Br ₂, AlCl ₃ with Cl ₂, AlBr ₃ with Br ₂

When reacting with methylbenzene (or other benzene compounds) , the position and products of the reaction change. In the bond between methyl and benzene, the electrons are leaning more towards benzene than methyl. When the electrons are 'pushed' towards the benzene ring, the group (halogens/nitrates/etc) can bond at the 2, 4, or 6 position. The product in the reaction is a mixture of chloromethyl benzene at the 2 and 4 positions. If excess chlorine/bromine is added, multiple halogens will bond at the 2, 4 and 6 positions. The result is a mixture of (2,4,6) and (2, 6).

With bromine, bromine water is added. Benzene will not react with bromine water but phenols will, forming 2, 4, 6 tribromophenol (white precipitate).

In a benzene compound where the connected group 'pushes' the (p orbital) electrons in the bond towards the benzene ring, the p orbital electrons form a 'partial double bond' with the p orbital electrons that the ring is made of. Since a double bond has a shorter length than a single bond, it has a higher bond strength, and therefore when a group is being added to a benzene compound, the added group is added in another position instead of replacing the already existing group since the bond of the already existing group is stronger.

Free-radical substitution can occur with methylbenzene. As usual, presence of UV light is needed, but since methylbenzene is very stable, it must also be at boiling temperature for methylbenzene. The hydrogen atoms at the benzene rings itself cannot be substituted.

The mechanism is similar with halogen substitution. The electrophile is NO ₂⁺and conc. HNO ₃ reacts with conc. H ₂SO ₄ (nitrating mixture) at 55 C to produce it. The reaction is:

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Christopher Setiabudi - Chapter ???: Benzene and Its Compounds

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Benzene Benzene is a hexagonal organic compound with 6 carbon atoms, 6 hydrogen atoms, and no double bonds. Originally, the Kekule structure, which was the first proposed structure, had 3 double bonds between the carbon atoms. However, it was proven to be incorrect as benzene was symmetrical, but

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Phenols

C6H5OH

Crystalline solid (melts at 43 degree celsius)

Has hydrogen bonding → melting point is high

Slightly soluble in water → large non polar benzene ring disrupts hydrogen bonding with water

Weakly acidic

Phenol > water > ethanol (acidity)

Lower pKa, better weak acid

Position lies to left-hand size (partially dissociated)

Preparation of phenol

Phenylamine + HNO2 (nitrous acid) (step 1)

Nitrous acid is unstable, made in test tube

NaNO2 (sodium nitrite) + HCl

Kept under 10 degree celsius

>10 degree celsius, nitrous acid will decompose → N2

Phenylamine + HNO2 + HCl → benzenediazonium chloride + H2O

Benzenediazonium chloride (step 2)

Benzenediazonium chloride + H2O → phenol + N2 + HCl

Phenol → phenoxide (C6H5O-) + H+

Phenoxide ion has negative charge spread over the whole ion (one of the lone pairs of O2 atom overlaps with pi bonding system in benzene ring)

Delocalisation → reduces charge density on phenoxide ion

Phenoxide ion is more stable

H ion are not strongly attracted to the phenoxide ion → more dissociated molecule

Reactions of phenol

React with alkali to form salt and water

Salt (sodium phenoxide) → soluble in water

React with sodium metal to form hydrogen gas and sodium phenoxide

Vigorously

Diazotization

Step 1 : Phenylamine + HNO2 (nitrous acid)

Step 2 : coupling reaction, diazonium ion reacts with alkaline solution of phenol (electrophilic substitution)

Positive diazonium ion acts as electrophile

4th position is activated

Orange dye is formed

Electrophilic substitution of phenols (halogenation)

Reacts more readily with electrophiles

The OH donating electrons to the benzene ring, increases the density of electrons in the pi system

No halogen carriers are needed (no catalyst)

Phenol is reactive

React with bromine water but milder conditions

Orange solution → white ppt.

Electrophilic substitution of phenols (nitration)

Room temperature and dilute nitric acid

No preparation is needed → no nitrating mixture is needed

If use concentrated nitric acid

2,4,6-trinitrophenol formed

Naphthol

NaOH  + 1-Naphthol --> phenoxide ion and water

NaOH + 2-Naphthol --> phenoxide ion (p2) + water

Na + 1-Naphthol --> phenoxide ion and hydrogen gas

2-naphthol + Na -> phenoxide ion (position 2) + hydrogen gas

Br2

HNO3

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phenol
- C6H5OH
- crystalline solid that melts at 43°C
- high mp due to hydrogen bonding
- slightly soluble in water (non polar benzene ring)
- weakly acidic (low pKa, more dissociation)
- electron-donating group (activate position 2, 4, 6)

preperation of phenol
- diazotisation
1. phenyl amine + HNO2 (NaNO2 + HCl, 5°C) + HCl → benzene diazonium chloride + 2H2O
2. benzene diazonium chloride + H2O + heat → phenol + N2 + HCl
3. coupling reaction : benzene diazonium + phenol + alkaline condition (NaOH) → azo dye (orange) + HCl phenoxide - C6H5OH → C6H5O- + H+

- negative charge spread all over the ion (overlaps with pi bonding in benzene ring = more stable than phenol)
- more H+ produced
- C2H5OH → C2H5O- + H+
- alkyl group (electron donating group)
- forms more ethanol
- less concentration of H+

reactions of phenol
1. phenol + alkali → salt + H2O
2. phenol + metal → phenoxide + H2
3. phenol + diazonium chloride → azo dye + HCl
- ethanol cannot react with NaOH (not good of a weak acid)
4. reacts with halogen (no need halogen carrier)
5. reacts with dilute NO2 (no need concentrated 55°C)

Naphthol
- 1-naphthol and 2-naphthol

Naphthol + NaOH → O- Na+ + H2O
Naphthol + Na → O- Na + + ½ H2
1-Naphthol + Br2/HNO3 → Br/NO2 will move to position 2, 4
2-Naphthol + Br2/HNO3 → Br/NO2 will move to position 1

I need to memorise the reaction and their condition more, and practice more past year questions. The lesson was clear and easy to follow as usual.

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PHENOL:

basically benzene with a hydroxide group attached to it

How phenol is a weak acid (as it dissociates to produce H+ ions!)

HOWEVER despite being a weak acid, phenol is still a better weak acid than water or ethanol! This is because it's able to dissociates to a larger extent, poe lies more to the right ! (the benzene group is a large, nonpolar ring, decreases charge density, negatively charged ion and H+ is less attracted to each other than that of, let's say, ethanol!)

Melting point at 43 degrees, relatively high mp because of hydrogen bonding

as you can see from the following reactions, phenol is much more reactive than benzene and thus require less harsh conditions. this is because phenol has a hydroxide group, and its oxygen atom had lone pairs—one of which would overlap with the pi bonding system. this makes it more susceptible to electrophilic attack.

PREPARATION OF PHENOL:

first, create a nitrous acid (and NaCl) is created from NaNO2 and HCl. HNO2 is formed

COUPLING REACTION: nitrous acid + HCl then reacts with phenylamine, to form an alkaline solution of benzene diazonium salt (the group is like,, N2+ Cl-)

Benzene diazonium salt is then warmed with H20, forming a phenol!!!!

REACTIONS OF PHENOL:

DIAZOTISATION (example of electrophilic substitution):

Benzene diazonium salt + phenol -> orange dye (4th position) + HCl

Requires NaOH presence

i cant draw it because i refuse to, but imagine two benzene groups, one has a hydroxide group, they're attached to each other due to a nitrogen-nitrogen bridge thing

*it acts exactly like an acid would in the following reactions*

W/ Na or NaOH

sodium phenoxide produced, either H2 or H2O produced respectively

W/ Bromine

Much more reactive, so less harsh conditions required

white ppt formed

bc of OH being an electron-donating group, the bromine atoms are substituted in 2,4,6 positions

W/ Nitration:
*once again, less harsh conditions are required as compared to benzene!*

w/ dilute HNO3: only one group is substituted in, resulting in a mixture of 2-nitrophenol and 4-nitrophenol!

w/ concentrated HNO3: all the groups are substituted in!!! so no mixture formed, 2,4,6-trinitrophenol formed!

Napthol Reactions!

the diagram is like,,, two benzene rings sticking to each other, one had a hydroxide group attached to it.

same reactions as everything else! it's just that WHERE the reactant/electrophile (??) is bonded to that changes in napthol.

1-napthol will have their reactants bonded to either the 2 or 4 atom

2-napthol, however—because it's too crowded to bond to carbon 4, but carbon 2 is already bonded to the hydroxide group—the reactants will bond to the first carbon atom.

Thanks for the lecture!! I wish we had more opportunities to do active recall though, so we can better remember things. Also, completely forgot about the physical properties of phenol lmao

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https://notability.com/n/2Z~FwJxll~ON2ShCkhw2MC

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Phenol Reactions

C6H5OH + NaOH → Sodium phenoxide + water

C6H5OH + Na → Sodium phenoxide + hydrogen gas (vigorous reaction)

Preparation

1. NaNO2 + HCl → HNO2 + NaCl (below 10°C)

2. Phenylamine + HNO2 +HCl → Benzenediazonium chloride + water

3. Benzenediazonium chloride (acts as electrophile) is heated with H2O, forming phenol + HCl + N2

Diazotisation

Benzenediazonium chloride (from previous reactions) + phenol → azo dye (orange) + HCl

With the presence of NaOH

An example of electrophilic substitution

Electrophilic Substitution of Phenols

Bromination: Milder conditions, decolourises bromine water, forms 2,4,6-tribromophenol (white ppt) and HBr, no catalyst needed

Nitration: rtp with dilute HNO3 forms 2 and 4-nitrophenol, and 2,4,6-trinitrophenol if conc. HNO3 is used

Naphthol Reactions

Similar reaction with Na and NaOH to that of phenol

1-Naphthol + Br2 → Br attaches to C2 and C4 since C6 is connected with the next ring

2-Naphthol + Br2 → No substitution in C4 since it is cluttered up with the other ring, so it substitutes the carbon atom between the other ring and the OH group

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From today's lecture, I’ve learnt about

• Phenols
- C6H5OH
- melting point at 43 °C, this mp is relatively high due to the hydrogen bonding
- weak acid,  in terms of acidity, phenol>water>alcohol
- slightly soluble with water (with non-polar structure benzene ring)
- can give phenoxide

• How to prepare phenols
- NaNO2 + HCl → HNO2 + NaCl
- Phenylamine + HNO2 +HCl → Benzenediazonium chloride + water
- Benzenediazonium chloride is then heated with H2O to form phenol + HCl + N2
- to prevent decomposition, kept under 10°C

• Reaction of Phenols
- C6H5OH + NaOH -> sodium phenoxide + H2O
^^salt(sodium phenoxide) is soluble in water
- 2C6H5OH + 2Na -> 2sodium phenoxide + H2 (vigorous)

• Diazotisation
- coupling reaction
- Benzenediazonium salt + phenol → azo dye + H+
(you can use Benzenediazonium chloride and HCl would form instead of H+)
- azo dye (orange dye)
- 4th position of phenol is activated

- electrophilic substitution

• Electrophilic Substitution of Phenols...
- Halogenation
> reacts more readily with electrophiles
> overlap of one of the lone pairs of electrons, increases the
electron density in the pi system
> react with bromine water but milder conditions.
> decolourizing orange solution to form white ppt

- Nitration
> room temp. and dilute HNO3

• Naphthol reactions
- has the same reaction as to how phenol reacts with Na and NaOH
- 1-Naphthol + Br2/HNO3 → Br/NO2
attaches to positions 2 and 4

- 2-Naphthol + Br2/HNO3 → Br/NO2
attached to position 1 as in position 4, there's no substitution since it is cluttered up with other rings

Overall, it was a great, clear and concise lecture as usual, but I feel like to fully remember and understand what we have just learned, I need to practice on doing past year paper questions.

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Phenol

C6H5OH

weak acid, low pKa

Crystalline solid that melts at 43°C which is quite high due to hydrogen bonding

Large non polar benzene ring disrupts the hydrogen bonding with water, making it less soluble

Phenol is a better weak acid than water than ethanol

Position of equilibrium lies more to the left because they dont dissociate

Preparation of phenol

To make HNO2: NaNO2 + HCl -> HNO2 + NaCl (kept at 5°C to prevent decomposition to give N2)

Phenylamine + HNO2 + HCl -> Benzenediazonium chloride + 2H2O

Benzenediazonium chloride warmed with water-> phenol + N2 + HCl

Phenoxide ion

C6H5O-

Its negative charge is spread all over the ion as one of the lone pairs overlaps with the pi bond, so the charge becomes less negative.

Phenol: The position of equilibrium shifts more to the right as C6H5O- and H+ will not attract each other as much, theres now more H+ and it is more acidic.

The delocalisation reduces charge density on the phenoxide ion, compared to hydroxide/ethoxide, so the H+ are not attracted to the phenoxide ion and only the dissociated molecule will be formed

Ethanol

alkyl group is electron donating, so the electron from C2H5 will be given to O-, hence more attraction with H+ and forming more C2H5OH

Reactions of phenol

C6H5OH + NaOH -> sodium phenoxide + H2O

2C6H5OH + 2Na -> 2sodium phenoxide + H2 (vigorous)

Diazotisation

2nd step Coupling reaction

Benzene diazonium salt + phenol -> orange dye (4th position) + HCl

Also an electrophilic substitution reaction

Electrophilic substitution of phenols (Bromination)

reacts more readily with electrophiles, as the OH donates electrons to benzene ring, increasing density of electron in benzene ring

Decolourises bromine water but with milder conditions

Forms 2,4,6 tribromophenol (white ppt) + HBr

Electrophilic substitution of phenols (Nitration)

Phenol + dilute nitric acid (rtp) -> 2-nitrophenol + 4-nitrophenol

Phenol + conc. nitric acid (rtp) -> 2,4,6-trinitrophenol

Naphthol + NaOH

1-naphthol + NaOH -> phenoxide ion + H2O

2-naphthol + NaOH -> phenoxide ion (position 2) + H2O

Naphthol + Na

1-naphthol + Na -> phenoxide ion + 1/2H2

2-naphthol + Na -> phenoxide ion (position 2) + 1/2H2

1-naphthol + Br2/HNO3 -> Br/NO2 is attached to position 2 and 4

2-naphthol + Br2/HNO3 -> Br/NO2 is attached to position 1, there cant be any substitution at position 4 because it is cluttered up with the other ring

Need to focus on: diazotisation and the equations fore preparing phenol

The lecture was very clear.

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Phenols

Electrophilic Substitution
- Halogenation
• Reacts more readily with electrophiles
• Overlap of 1lp of electrons,
• Increases the electron density in the pi system
• React with bromine water in milder conditions.
• Decolourizing orange solution to form white ppt

- Nitration
• Room temperature
• Dilute nitric acid
• If concentrated nitric acid used, forms 2,4,6 - trinitrophenol

Reactions of Naphthol

- Naphthol + Na
- Naphthol + NaOH
- 1-Naphthol + Br2
- 2-Naphthol + Br2
- 1-Naphthol + HNO3
- 2-Naphthol + HNO3

Reactions with Naphthol
https://1drv.ms/b/s!Aqg3rLnTbWQmgTxktExsuH0ZKKzd

Areas I need to focus on : Memorizing the reactions
Lecture : Good

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Store photos and docs online. Access them from any PC, Mac or phone. Create and work together on Word, Excel or PowerPoint documents.

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Revised on :
- electrophilic substitution ( halogenation )
- free radical substitution
- electrophilic substitution ( nitration )

Learnt about :
- friedel crafts reaction
1. Alkylation -> reaction w/ alkyl groups
2. Acylation -> reaction w/ acyl groups
- oxidation of arenes
- phenols -> C6H5OH
- phenoxide vs ethoxide ion
- reaction of phenols :
1. with NaOH
2. with Na
3. Diazotisation
4. Electrophilic substitution ( halogenation )
5. Electrophilic substitution ( nitration )
- naphthols : phenol with another benzene ring
- naphthols (1-naphthol and 2-naphthol ) reactions :
1. w/ Na
2. w/ NaOH
3. w/ Br2
4. w/ HNO3

Need to focus more on :
Diazotisation and its reactions

Teaching :
Fast but clear enough

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Phenol

- Preparing phenol includes HNO2 and HCl where it makes C6H5N2+Cl-
- Negative charges are spread all over the ion
- lone pairs in oxygen atom overlaps with the pi bonding ring in the benzene ring. This will spread the charge all over the ion which decreases the intensity of the charge.
- Attraction between the H+ ion and the O- ion in the OH branch becomes weak and more phenoxide is produced. This results in an increase in H+ ions which causes it to be a stronger weak acid.
- Phenoxide is more stable than phenol

Reactions of Phenol

- React with alkali to from salt (sodium phenoxide) adn water
- The salt is soluble in water
- Phenol reacts with sodium hydroxide in which ethanol cannot. This is simply because phenol is a better weak acid than ethanol.
- phenol reacts vigorously with sodium

Coupling Reaction

- It is when phenol reacts with C6H5N2+Cl-
- position 4 of the phenol benzene ring will join with the nitrogen of It is when phenol reacts with C6H5N2+Cl- making azo dye which is orange in color and has a side product of HCl.

Electrophilic subsitution of phenols

halogenation

- Reacts readily and does not need any catalyst or intermediate
- Reacts with bromine but in milder conditions
- Overlap of the one of the lone pairs of electrons, increases the electron density in the pi system
- Product has bromine molecules in all 2, 4, 6 positions of the benzene ring
- Decolourizing orange solution to form white ppt
- no catalyst means no need for AlBr3

Nitration

- room temperature and dilute nitric acid substitutes only one NO2 molecule
- concentrated nitric acid substitutes all 3 N02 molecules to the 2, 4, 6 positions

Naphthol

reacts with:
- NaOH
- Na
- Br2
- HNO3

2-Naphthol with Br

- OH ion is on the second position of the benzene ring.
- Br will go to the first position of the ring where it is placed between the OH ion and the other benzene ring.