Organic Chemistry Lab Reports: Synthesis and Reaction Analysis

This document presents a series of organic chemistry lab reports. The first report focuses on the cracking of dicyclopentadiene into cyclopentadiene, which serves as a diene in Diels-Alder reactions. It details the pre-lab questions, the purpose of the experiment, the background of the Diels-Alder reaction, and the chemical reactions involved. The second report investigates the regiochemistry of electrophilic aromatic substitution reactions with monosubstituted aromatic compounds, covering the effects of substituents on reaction rates and orientation. It includes pre-lab questions, chemical reactions, and calculations related to the mononitration of acetanilide and methyl benzoate. The third report explores a nucleophilic aromatic substitution reaction of 3,4-dichloronitrobenzene with sodium methoxide, outlining potential products and reaction mechanisms. These reports provide a comprehensive overview of key organic chemistry concepts, including reaction mechanisms, synthesis, and analysis, making them valuable resources for students studying organic chemistry. The document is contributed by a student to be published on the website Desklib. Desklib is a platform which provides all the necessary AI based study tools for students.

Running head: ORGANIC CHEMISTRY: LAB REPORTS
1
Organic chemistry: lab reports
Name:
Institution:

ORGANIC CHEMISTRY: LAB REPORTS 2
PRE-LAB 1
Purpose of the experiment
The aim of this experiment is cracking of dicyclopentadiene into cyclopentadiene.
Cyclopentadiene act as diene for the Diels-alder reaction. To break the compound
(dicyclopentadiene), one will use the fractional distillation, which comprises boiling the mixture
to remove a particular compound by recondensing it. Cyclopentadiene has much lower boiling
point that the original compound, and therefore, one will be able to remove it and use for the
reaction. Then, maleic anhydride is dissolved in solvents and then slowly added to
cyclopentadiene.
Background of experiment
The Diels-alder reaction is very significant because it forms carbon-carbon bonds. The
image below describes the mechanisms for the reaction. The two carbon-carbon bond (diene)
reacts with the dienophile which has c=c to produce a six carbon ring referred to as cyclohexene.
The red illustrates the electron movements which exist in the pie pairs, where the pie pair links
together to form double bonds. The reaction is relatively simple and always happens in the same
manner with an identical reacting group.

ORGANIC CHEMISTRY: LAB REPORTS 3
A cyclo-addition comprises the 1, 4-addition of the conjugated diene in the cis
configuration to a double (–c=c-) in which two novel sigma are made from two pie bonds. The
product is a 6-membered ring alkene. The diene may have two conjugated links confined within
the ring web, as with cyclopentadiene or the molecule can be an acyclic diene that ought to be in
the cis configuration about the –c-c- (single) bond before the reaction occurs.
The process is viable where there is significant variance between the e- masses in the
diene and the alkene. Typically, the dienophile has electron-drawing group linked to it, whereas
the diene is electron sufficient. Configuration retention of the reactant in the product denotes
that both novel alphas are made nearly concurrently. If not, the intermediates with a lone novel
bond could revolve about that bond before the second alpha link is created, thus, rescinding the
reaction stereospecificity.
The procedure is known as concerted reaction since it is not polar reaction; it is a radical
reaction since no unpaired electron is involved. When the cyclic dienophile and cyclic diene
react, more than one stereoisomer may be generated. Predominate isomers are one that includes
the extreme overlay of pie electrons in the conversion state. Roald Hoffmann and Woodward
Robert formulated the hypothetical guidelines encompassing the connection of orbital
equilibrium which governs the Diels-Alder and any other electrocyclic reaction. The Diels-alder
course has been used lengthily in the production of multifaceted natural produces because it is

ORGANIC CHEMISTRY: LAB REPORTS 4
promising to achieve the creation of many chiral midpoints in one reaction, and more so, because
of the regioselectivity of the reaction.
Cyclopentadiene is usually got from the light oil but is created from coal extraction. In
addition, it exists as a firm dime in the form of dicyclopentadiene, which is the Diels-Alder
product from the two fragments of the diene. Therefore, cyclopentadiene formation by pyrolysis
of the dimer denotes an opposite Diels-Alder reaction. In the maleic anhydride and
cyclopentadiene reaction through the Diels-alders addition, the two molecules approach each
other as the orientation offers greatest overlay of pie bond of the two reacting particles and then
favor the creation of first pie compound.
Chemical reaction
dicyclopentadiene Density 0.98, Molecular weight 132.20, boiling
point 1700C
cyclopentadiene Density 0.80, molecular weight 66.10, boiling

ORGANIC CHEMISTRY: LAB REPORTS 5
point 410C
Maleic anhydride Molecular weight 998.05, melting point 530C
Cis-Norbornene-5,6-endo-dicarboxylic
anhydride
Melting point 1650C, molecular weight 164.16.
Pre-lab question
Question 1
Cracking means heating above the boiling point of cyclopentadiene. Because it starts distilling at
a temperature of 40-420C and before reaching this temperature, it cannot be purified.
Question 2
2a 1,2dimethyl, 5-cyano hexadiene
2b 6 methoxy-9-methylanthracene
2c 2-propanenitrile furan
Question 3
Reactants: 2-methyl-1, 3, butadiene and 2 methyl 1, 3, butadiene
Question 4

ORGANIC CHEMISTRY: LAB REPORTS 6
The cantharidin would not have been formed because in the Diels-alder adding of
cyclopentadiene and maleic anhydride, the two fragments have an alignment that offers the
minimal overlay of pie bond of the two reacting particles, and favor the creation of an original
composite and then the end product
PRE-LAB 2
Purpose of the experiment
It aims to demonstrate regiochemistry of electrophilic aromatic substitution process for
monosubstituted aromatic composites.
Background
One should be conversant with the melting point dimension, vacuum filtration, and
recrystallization systems. In the benzene ring, the electron density is all uniform at all the carbon
atom. Hence, the incoming electrophile has no favorite choice and may occupy any position.
The presence of the substituent disturbs the uniform distribution of the electron density around
the benzene ring. Thus, affects the behavior of the remaining hydrogen atom in the various ways.
The substituents jeopardize the stability of the transition state relative to that of the reactant
(benzene). Since the arenium ion (Ar+) is positively charged, electron releasing group stabilize
the transition state and the arenium ion. An electron removing group creates the Ar + less stable
and transition state making arenium ion being less steady.
On the side of an Ortho-Para directors: except for the phenyl and alkyl group, all the
ortho Para directing group have at least one pair of the non-bonding electron on the carbon atom
adjacent to the benzene ring. Thus, this determines the orientation and influences reactivity in

ORGANIC CHEMISTRY: LAB REPORTS 7
the electrophilic substitution. It is worth noting that the halo group is only the ortho-Para
directors that are deactivating. This is because their withdrawing inductive effect influences the
reactivity and their electron releasing resonance governs orientation. For instance, the
chlorobenzene, chlorine atom is highly electronegative; withdraws electrons from the benzene
ring, thereby deactivating it. When the electrophilic attack takes places, the Cl group stabilizes
the Ar+ occasioning from the ortho Para attack relative to that of the Meta attack by giving an
unshared brace of electrons. Therefore, one can classify the ortho, Meta and Para directors in the
following criteria.
Ortho Para directors with strong activation include the following: amine, alkyl or aryl
amines, hydroxyl, and ozonide groups. Ortho Para directors that are moderately activating
include the methoxy, ketones, and amides groups. Ortho Para compounds that are weakly
activating include the aryl, alkyl group. Finally, the weakly deactivating compound which is
ortho Para directors consists of the halogens groups. Meta directors that are moderately
deactivating include the cyanide, sulphonic, carboxylic, esters, ethers, and aldehyde groups. And
finally, the strongly deactivating compounds have nitro, tertiary amines, and aryl halides groups.
Greatest replacement reaction at aliphatic C atoms is nucleophilic, but, the aromatic
substation is electrophilic due to high electron density around the benzene circle. The most
electrophilic substitution mechanism of aromatic is the Ar ion mechanism. To accurately design
a trial comprising an electrophile disubstitution reaction done on monosubstituted benzene,
numerous elements ought to be observed. The substituent elements existing on the loop may
cause the substitution process to being quicker or sluggish than the initial reaction of the benzene
molecule. Activators give the electrons, increasing the electron compactness of the aromatic loop
and thus stabling the Ar ion. Other promoters making Ar being stable is through the

ORGANIC CHEMISTRY: LAB REPORTS 8
hyperconjugation which is the overlay of an adjacent sigma link with the aromatic pie structure.
Substituent that decreases the reaction rate is referred to as deactivators, as they decrease the
electron density around the aromatic ring. Inductive effect results from the electronegativity
variances in the bonding atom.
Additionally, the electronic type of the substituent influences the locus of the
electrophilic substitution. Three regioisomers exist for disubstituted aromatic: ortho, Meta and
Para. Inductive of the substituent arises from the electrostatic interaction of polarized
constituents to ring bond with developing positive charge in the ring if the electrophile attacks it.
If the substituents are more electronegative atom than the carbon, then, the ring is at definite end
of the dipole. The entire Meta directing group has either an incomplete positive or a full positive
charge on the particle directly linked to the ring.
The electron drawing sets are referred to as Meta directors. Halogens are ortho-Para
deactivators as they have both particles releasing inductive properties and electron-contributing
resonance impacts. For that case, a molecule that is directed linked to the aromatic loop and has a
solitary pair electron is an ortho-Para director.
Nitration is one of the essential instances of electrophilic substituting. Aromatic nitro
elements are useful in produces going from explosives to synthetic medicinal intermediaries.
The electrophile in nitration is the nitronium which is made from a nitric acid by protonation and
water loss, using sulfuric acid as a dehydrating agent. On the electrophilic substitution of the
benzene ring, phenols can be used to manufactures, dyes, plastics, drugs, explosives, pesticides,
and explosives.

ORGANIC CHEMISTRY: LAB REPORTS 9
Figure 1:arenium ion mechanism for the electrophilic aromatic substitution
Figure 2: resonance forms of a substituted arenium ion.
Chemical reaction

ORGANIC CHEMISTRY: LAB REPORTS 10
Acetanilide Melting point 113-1150C, molar mass 135.17,
toxic and irritant
Ethanol, 95% Molar mass 46.0, boiling point 780C, irritant
and flammable
methyl benzoate Molar mass 136.15, melting point -120C,
boing point 198, irritant
nitro acetanilide Molar mass 180.163, Irritant
Nitric acid Molar mass 63.01, toxic and oxidizer
Sulphuric acid Molar mass 98.08, poisonous and oxidizer
Methyl nitro benzoate Molar mass 137.138

ORGANIC CHEMISTRY: LAB REPORTS 11
Pre-Lab questions
Question 1
Caution should be taken when using sulphuric and nitric acid because of the oxidizing
and toxic nature of compound as they can cause a severe burn. Therefore, one should prevent
skin, clothing, eye and combustible material coming into contact. Also, one should avoid
inhaling vapors and ingesting these compounds. Another caution is that when mixing
concentrated nitric and sulphuric acid, the reaction is exothermic. Hot acid mixtures can bump to
cause severe burns. Thus, usage of fume hood and making sure the acid are cold before the
mixing is of essence.
Question 2
2a (i) bromobenzene-ortho-Para director
(ii), nitrobenzene-meta director
(iii), benzoic acid-meta director
(iv), toluene-ortho-Para director
(v), phenol-ortho-Para director
(vi), benzaldehyde-meta director
B: phenol is the more reactive compound: this is because the hydroxyl group is strong activators
which cause the aromatic ring to be more reactive.

ORGANIC CHEMISTRY: LAB REPORTS 12
C, nitrobenzene is less reactive because the nitro group is a strong deactivating group that causes
the aromatic ring to be less reactive than benzene. Substituents groups can also be categorized
into classes according to the way they influence orientation attack by the incoming electrophile.
3: calculation
Mononitration of acetanilide
Moles of the acetanilide =0.5/135.17=0.003699moles
Moles ration of the reactants to the products is 1:1
Therefore, the theoretical yield of the Mononitration of the acetanilide is
0.003699* (molar mass of nitroacetanilide-180.163) = 0.666grams
Mononitration of methyl benzoate
Moles of methyl benzoate = 0.55 grams/136.15=0.00402moles
Moles ration of reactant and product is 1:
Yield of methyl nitrobenzene= 0.00402* (molar mass of methylnitrobenzene-137.138)
=0.55grams
Post lab question.
In the process of nitrating toluene to get 2, 4,-trintrotoloune, the first nitration is favored because
the nitro compound is a potent deactivating compound which is a Meta director.