LECTURE 21 REFLECTION ON PHENOL (PART 2) by Pooganeswari Siteram Pillai

Benedict JC2T

2022-01-20 09:24:59 UTC

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.

Jasmine JC2T

2022-01-20 09:58:52 UTC

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

Jennifer JC2G

2022-01-23 19:10:27 UTC

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

Angela JC2G

2022-01-24 00:15:33 UTC

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.

Dylan JC2G

2022-01-24 00:29:54 UTC

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.

Ella JC2G

2022-01-24 00:36:11 UTC

Phenol Reactions

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

Preparation

NaNO2 + HCl → HNO2 + NaCl (below 10°C)
Phenylamine + HNO2 +HCl → Benzenediazonium chloride + water
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

Josh JC2G

2022-01-24 01:00:28 UTC

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

Ashley JC2G

2022-01-24 02:10:49 UTC

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

Keira JC2G

2022-01-24 02:30:51 UTC

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.

sharon jc2T

sharonchristiehalimm — 2022-01-25 02:41:12 UTC

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

Chris JC2T

2022-01-25 02:47:36 UTC

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

Frederic JC2T

2022-01-25 02:49:37 UTC

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

Josh JC2T

2022-01-25 02:50:35 UTC

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.

Ryan JC2Truth

2022-01-25 02:51:44 UTC

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

Michael jc2t

2022-01-25 02:53:39 UTC

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

MichelleV JC2T

2022-01-25 02:55:30 UTC

- 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- 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

Jacksen JC2T

2022-01-25 02:59:00 UTC

- 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

Catherine JC2T

2022-01-25 03:17:55 UTC

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

Yeewen JC2T

yeewenpoh — 2022-01-25 03:27:39 UTC

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

Jonathan

2022-01-25 06:38:50 UTC

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.

michelle jc2 grace

2022-01-25 06:40:12 UTC

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+

Kendrew JC2G

2022-01-25 07:04:34 UTC

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-

Nevan Kho Jc2G

2022-01-25 07:22:02 UTC

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

Jordan Jc2G

2022-01-25 17:06:14 UTC

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.

Earlene JC2G

2022-01-25 18:34:18 UTC

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 (2^nd 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