34 Questions
What is the characteristic of an aromatic nitro compound?
The nitro group (NO2) is attached directly to an aryl group
What is the hybridization of the nitrogen atom in the resonance structure of a nitroalkane?
sp2
What is the product of the reaction of 1,5-dinitropentane with Zn/HCl?
1,5-diaminopentane
What is the difference between an alkyl nitrite and a nitroalkane?
They have different structural arrangements
What is the reaction condition for the preparation of nitroalkanes from alkanes?
400°C and HNO3
What is the product of the reaction of nitropropane with Zn/HCl?
Propanamine
What is the characteristic of the coordinate covalent bond in the structure of nitroalkanes?
N is the donor and O is the acceptor
What is the reagent used in the preparation of nitroalkanes from alkanes?
HNO3
What is the product of the reaction of alkyl halide with AgNO2?
R-NO2
What is the type of reaction that occurs between nitroalkanes and aldehydes or ketones in the presence of a base?
Aldol type reaction
Which of the following nitroalkanes does not react with aldehydes?
Tertiary nitroalkane
What is the name of the compound with the structure CH3C6H3(NO2)2?
o-Dinitrobenzene
What is the general mechanism for the preparation of aromatic nitro compounds?
Direct nitration
What is the effect of a m-directing group on the nitration of substituted benzene?
It deactivates the ring towards nitration
What is the name of the compound with the structure C6H3(NO2)3?
1,2,3-Trinitrobenzene
What is the role of AgNO2 in the preparation of nitroalkanes from alkyl halides?
It acts as a reactant
What is the effect of o,p-directing groups on the activity of benzene ring towards electrophiles?
They increase the activity of benzene ring towards electrophiles and require harsh conditions.
What is the result of nitration of phenols and aniline?
A mixture of mono, di, and trinitro products is obtained along with oxidation products.
Why is protection necessary for nitration of aromatic compounds containing OH or NH2?
To prevent oxidation of the functional group.
What is the purpose of acylation in nitration of aromatic compounds containing OH or NH2?
To protect the functional group from oxidation.
What is the effect of meta-directing groups on the activity of benzene ring towards electrophiles?
They decrease the activity of benzene ring towards electrophiles and require harsh conditions.
What is the condition required for nitration of nitrobenzene?
Harsh conditions and concentrated acid.
What is the product of nitration of toluene?
A mixture of o-nitrotoluene and p-nitrotoluene.
Why do o,p-directing groups require mild conditions of reaction?
Because they are electron donating groups.
What is the primary function of the acetyl group in the given reaction?
To protect the OH and NH2 groups
What is the major product of the direct nitration of anisole using HNO3/H2SO4?
o-nitroanisole
What is the role of HNO3 in the mechanism of reaction B?
It provides the nitro (NO2) group which gives the p-isomer
What is the byproduct of the reaction mechanism of reaction B?
H2O
What is the intermediate formed in the mechanism of reaction B?
A six-centered intermediate
What is the reagent used in the indirect method of preparing aromatic nitro compounds from amines?
Trifluoroperacetic acid
What is the major product of the reaction of anisole with acetyl nitrate?
p-nitroanisole
What is the role of the acetyl group in the reaction of anisole with acetyl nitrate?
It protects the OH group and directs the nitration to give the p-isomer
What is the purpose of using acetic anhydride in the reaction of anisole with acetyl nitrate?
To prepare the acetyl nitrate reagent
What is the reason for the formation of the p-isomer as the major product in the reaction of anisole with acetyl nitrate?
The acetyl group directs the nitration to the p-position
Study Notes
Nitrogenous Compounds
- Nitro compounds: aromatic nitro compounds and aliphatic nitro compounds
- Aromatic nitro compounds: nitro group (NO2) attached directly to aryl group
- Aliphatic nitro compounds: nitro group (NO2) attached directly to alkyl group
Structure of Nitroalkanes
- Resonance structure and resonance hybrid of nitroalkanes
- Coordinate covalent bond between nitrogen and oxygen
Nomenclature of Nitroalkanes
- Nitropropane: CH3-CH2-CH2-NO2
- 1,5-Dinitropentane: NO2-CH2-(CH2)3-CH2-NO2
Alkyl Nitrite
- Isomer of nitroalkanes: same number of atoms but different arrangement
- R O N O
Preparation of Nitroalkanes
- From alkanes: heating with HNO3 at 400°C
- From alkyl halides: reaction with AgNO2
Reactions of Nitroalkanes
- Condensation reaction with aldehydes and ketones in presence of base
- Aldol-type reaction: active methylene group with acidic hydrogen
- Tertiary nitroalkanes do not react with aldehydes due to absence of acidic hydrogen
Aromatic Nitro Compounds
- Nomenclature:
- 1,2-Dinitrobenzene, 1,3-Dinitrobenzene, 1,2,3-Trinitrobenzene, etc.
- Preparation:
- Direct nitration of aromatic compounds using HNO3 and H2SO4
- Nitration of substituted benzene: m-directing group (deactivating) and o,p-directing group (activating)
- Protection of OH and NH2 groups using acylation
Preparation of Aromatic Nitro Compounds (Indirect Methods)
- From amines: oxidation using trifluoroperacetic acid or peroxytrifluoroacetic acid
- By using o-nitrating agent (acetyl nitrate) to prepare o-nitrophenol
This quiz covers the basics of nitrogenous compounds, including nitro compounds, aromatic and aliphatic nitro compounds, and their structures. It also touches on amines and diazonium salts.
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