Other
applied science unit 14d
- Course
- Institution
distinction grade given
[Show more]
Seller
Follow
salmanj1810
Content preview
14DIntroduction:
Electrophilic substitution is a method by which an electrophile is able to replace a hydrogen
atom on an aromatic ring in benzene. Halogenation, alkylation, acylation, and nitration are all
examples of common substitutions.
Nitration of methyl benzoate:
The reactants are methyl benzoate, nitric acid, and sulfuric acid, yielding water and methyl
3-nitrobenzoate as products. The reactant contains the ester functional group and a benzene
ring, while the products are the ester and nitro functional groups, as well as a benzene ring.
Methylbenzoate + nitric acid → methyl 3-nitrobenzoate + water
HNO3 + H2SO4 → HSO4- + NO2+ + H2O
Mechanism:
,The nitration of benzene is a chemical reaction in which a nitro group (-NO2) is added into a
benzene ring. This reaction is carried out by treating benzene with a mixture of concentrated
nitric acid (HNO3) and concentrated sulfuric acid (H2SO4) as a catalyst. The sulfuric acid
acts as a dehydrating agent, helping to mKe the nitronium ion (NO2+), which is the
electrophile responsible for attacking the benzene ring.
In the first step of the reaction, the nitronium ion is formed
HNO3 + H2SO4 → NO2+ + HSO4- + H2O
The nitronium ion then attacks the benzene ring, substituting one of the hydrogen atoms
attached to the ring with a nitro group:
C6H6 + NO2+ → C6H5NO2 + H+
This substitution reaction results in the formation of nitrobenzene, with the loss of a proton.
The overall reaction is an example of electrophilic aromatic substitution, where the
electrophile (NO2+) attacks the benzene ring.
The formation of the nitronium ion NO2+ occurs when sulfuric acid and nitric acid combine,
serving as an electron pair acceptor. The nitronium ion accepts a pair of electrons from the
delocalized electrons in the benzene ring, forming a dative covalent bond with the nitrogen
atom. This process generates an unstable positively charged intermediate with a broken ring
of delocalized electrons.
The breaking of the C-H bond by heterolytic fission happens on the carbon attached to the
NO2, which then restores the ring of delocalized electrons. This process the formation of a
benzene ring through the elimination of a hydrogen ion from the intermediate. Consequently,
this results in increased stability as the ring of pi electrons is regenerated. The resulting
hydrogen ion combines with HSO4- to regenerate the catalyst for sulfuric acid.
Conditions for alcohols
The conditions for the nitration of alcohols involve using a mixture of concentrated nitric acid
(HNO3) and concentrated sulfuric acid (H2SO4) as a catalyst.
Concentrated nitric acid is a strong oxidizing agent that provides the nitro group (-NO2)
required for the nitration reaction. nitric acid alone is not good in nitrating aromatic
compounds due to not being an electrophile. Therefore, concentrated sulfuric acid is added
as a catalyst to generate the nitronium ion (NO2+), which is the electrophile responsible for
the nitration of the alcohol.
Risk Assessment:
Hazard Risk Control measure
Methyl benzoate - Acute Toxicity - Keep away from
- Harmful to swallow open flames, hot
, - contaminate sources and ignition
sources.
- Skin protection
(gloves).
- Tightly close
container. (1)
Concentrated HNO3 - Oxidising liquid - Do not breathe
- Corrosive to metals vapours
- Skin corrosion - Avoid substance
- Serious eye damage contact
- Adequate ventilation
(2)
Concentrated H2SO4 - Corrosive to metals - Wear acid resistance
- Skin corrosion protective clothes
- Severe skin burns - Wear goggles
and eye damage (3)
Ethanol - Flammable liquids - Keep away from
- Serious eye irritation heat, hot surfaces,
open flames.
- Ventilation
(4)
Equipment:
● Goggles
● Conical flask
● 2 250cm3 beakers
● A 100cm3 beaker
● 3cm3 pipettes
● Iced cube
● Filter papers
● Small thermometer
● Balance
● 2 test tubes
● 10cm3 measuring cylinder
● 25cm3 measuring cylinder
● Bunsen burner
● Heat proof mat
● Tripod
● Gauze
● Spatula
● Filtration apparatus
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller salmanj1810. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $9.35. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
75759 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now