Nitration of phthalic acid and phthalic anhydride then reduction of nitro group to amino group was investigated in this lab report

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Phthalic acid and phthalic anhydride
By
Shahrbano Awan
Submitted to
Dr.Aysha
Session 2014-1018
GC woman university Sialkot

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Table of contents
Sr.
No
Page
No
1 CHAPTER.1…… Introduction 6
2 1) 1,2-Benzenedicarboxylic acid 6
3 1.1 Isomers 6
4 1.2 Uses 6
5 1.3 derivatives of phthalic acid 7
6 2) Previous synthetic approach 7
7 3) Phthalic anhydride 8
8 3.1 Uses 8
9 3.2 Derivatives of phthalic anhydride 8
10 CHAPTER. 2…. nitration of phthalic acid 9
11 2) reduction of nitro gruop 9
12 3)Production of 10
13 CHAPTER. 3 Resultant and discussions 11
15 Reference 16

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Table of figures
Sr.No Page
No
1 Figure 1 6
2 Figure 2 6
3 Figure 3 8
4 Figure 4 8
5 Figure 5 9
6 Figure 6 9
7 Figure 7 10
8 Figure 8 11
9 Figure 9 13

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CHAPTER 1
(Introduction)
1. 1,2-Benzenedicarboxylic acid
Phthalic acid is an aromatic dicarboxylic acid with molecular
formula C6H4(CO2H)2. It’s an isomer of isophthalic
acid and terephthalic acid. Although (1,2-benzenedicarboxylic
acid) phthalic acid is modest commercial importance, the most
important derivative phthalic anhydride is a basically used
chemical produced on an industrial scale. [1]
1.1 Isomers Fig 1
Phthalic acid has three isomers of benzenedicarboxylic acid, the others being isophthalic acid
and terephthalic acid Sometimes the term "phthalic acids" is used to present to this family of
isomers, but in the singular, "phthalic acid", refers exclusively to the ortho- isomer.[2]
Fig 2
1.3 Uses
Phthalic acid is used mainly in the form of the anhydride to produce other chemicals such as
dyes, perfumes, saccharin, phthalates and many other useful products. In view of this and our

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interest in biologically active coordination compound, the present work communicating the
synthesis, characterization and biological activity of M2+(M=Cr, Co, Ni, Cu, Zn) with benzoic
acid as ligand. Aniline derivatives have been actively investigated because of their fascinating
biological and diverse ligational behaviour towards metal ions and novel structural features in
their complexes . We have made studied the coordination and biological chemistry of 2-(4-
nitrophenylaminocarbonyl)benzoic acid.[3-4]
1.4 Derivatives of phthalic acid
Interest in amino acids has increased enormously during recent years mainly because of the
many new uses which have been found for these compounds in nutritional and medical fields.
Additional reagrnts for the characterization of amino acids are accordingly useful. Succinic
anhydride and maleic anhydride were investigated as reagents but proved to be unsatisfactory.
However phthalic anhydride gives compounds of excellent properties with a large number of
amino acids. A solution of phthalyl L-leucine when examined polarimetrically was found to be
optically active. This confirms the findings of Fox4 and Reese.6 Phthalyl L- acid likewise was
found to be optically active. Since racemization does not appear to occur during their
preparation, phthalyl Derivetives should be valuable for the rapid characterization of optically
active amino acids. Tryptophan, tyrosine, serine and taurine did notgive the desired
derivatives.[5]
2. Previous synthetic approach
Coordination compounds have been a challenge to inorganic chemist since they were identified
in the 19thcentury. They deny the usual rules of valence at that time and hence called complexes.
They play a vital role in our lives. Transition metal complexes with soft or hard donor groups
have been used extensively in coordination and organometallic chemistry [6]. Reaction of
coordinated Ligands model systems of biological interest, analytical chemistry, agriculture and
optical display devices [7-8]. Resistance to the presently accessible antibiotics has motivated the
search for new agents to inhibit bacterial activity. Among such agents, metal complexes of
biologically active ligands are attractive as both legends and metal ions can interact with
different steps of pathogenic life cycles[9-10].
For the last two decades , the synthesis of coordination compound with transition metals and
their application have become an attractive field because of theirexcellent properties such as
catalysis, microelectronics, medical, nonlinear optics and porous material.Recently a few reports
on the antimicrobial activity of Mn(II) complexes were studied[11]. Phthalic acid and its anion
can make a large number of coordination compounds with different metals, and because of
presence of two carboxtlic group at ortho position the propensity of phthalates to forms a large
number of metal-oxygen bond upon complexetion [12].Among these, ortho- phthalic acid
(H2Pht) is a versatile dicarboxylic ligand and has been widely used in the design of Coordination
compounds with different metals[13]. There are a number of reasons for inducing interest in
this compound. Phtalic acid and its derivatives are widely used in the formation of complexes

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because of two carboxylic groups that are having great affinity for different transition metals as
Zn, Cu, and Co[14]. Being a part of metalloprotien and performing essential biochemical
activities in living things these compounds are used as artifial models to study biological process
in biosystems[15]
3 Phthalic anhydrite
Phthalic anhydride is the organic compound with the formula C6H4(CO)2O. It
is the anhydride of phthalic acid Phthalic anhydride is a principal commercial
form of phthalic acid. It was the first anhydride of a dicarboxylic acid to be used
commercially. This colourless solid is an important industrial chemical,
especially for the large-scale production of plasticizers for plastics. In 2000, the
worldwide production volume was estimated to be about 3 million tonnes per
year.[16] Fig 3
3.1 Uses
The primary use of phthalic anhydride is as a chemical intermediate in the production of plastics
from vinyl chloride. Phthalate esters, which function as plasticizers, are derived from Phthalic
Anhydride. Phthalate plasticizers are used for the production of flexible PVC products such as
cables, pipes and hoses, leather cloth, shoes, film for packaging etc. Phthalic anhydride has
another major use in the production of polyester resins and other minor uses in the production of
alkyd resins used in paints and lacquers; certain dyes (anthraquinone, phthalein, rhodamine,
phthalocyanine, fluorescin, and xanthene dyes); insect repellents; and polyester polyols for
polyurethanes. It is also utilized as a rubber scorch inhibitor and retarder.[17-18]
3.2 Derivatives of Phthalic anhydride and application
Phthalic anhydride (C6H4(CO)2O) is colorless solid and an important industrial chemical,
especially for the large-scale production of plasticizers for plastics [19]. The phthallic anhydride
ring opening reaction by alcohols when carried out in presence of different metal salts, results in
the formation of metal carboxylate complexes [20]. The
phathalate esters are also produced via phthallic anhydride
ring opening reaction used for chiral separation of optically
active alcohols and amines [21], however in the presence of
amino acids such as glycine, the reactions of phthalic
anhydrides help in preparing N-phthaloylglycinato
complexes of transition metals [22]. The metal complexes
of amino acids with phthalic anhydride revealed higher
antimicrobial activity P. aerugenosa, E. coli, S. aureus and

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C. albicans than their respective ligands [23]. Fig 4
CHAPTER 2
PROCEDURES
Nitration of phthalic acid (1,2-Benzenedicarboxylic acid)
Fig 5
1 gram phthalic acis was taken in a conical flask and 3eq of sulfuric acid also added. Shake and
stirrer the above mixture till all the phthalic dissolve in the sulfiuric acid. When phthalic fully
dissolve inacid, measured amount of nitric acid added drop wise and it act as the source of
nitronium ion. Perform TLC frequently to check wether the reaction occure or not. Reacting
miture must not be heated other wise it will waste or desire product will not form, if necessary
heated at low temperature.
Reduction of 4-nitrobenzene-1,2-dicarboxylic acid
Fig 6
4- nitrophthalic acid was prepared now reduce by the help of hydrochloric acid and zinc metal.
Zinc metal measured about 0.59 and made the powder of metal by grinding and crushing.

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Hydrochloric acid was measured in measuring cylinder that was about 10 ml and added to the
solution in 4-nitrophthalic acid. Zinc dust was added in the above solution in small quantity after
every 5 minutes until it was finished. Reaction must be carried out at room temperature in order
to avoid complex formation , in case if it was heated zinc can make complexes with a corboxlylic
group of phthalic acid. Reaction was continued about 2 hours with constant strriring. The
original product was yellow in colour, but after reduction it became brown and this the clear
sign of reaction progress.
Formation of phthylamide
Fig 7
Phthalic acid took about 2g in 15ml of ethanol in order to dissolve completely. Heat the above
mixture in a water bath When phthalic acid was dissolved completely, aniline about 2.70ml
added drop wise with constant stirring . Off white color ppts wese formd, left the ppts for drying.
The product was much less polar as compared to phthalic acid, so it was summed up at the
bottom.

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CHAPTER 3
Resultant and discussion
A mixture of concentrated nitric acid or nitrogen oxides with inorganic compounds (H2SO4, BF3,
and AlCl3) or organic compounds (for example, acetic anhydride). It generates the active nitratin
gspecies NO2
+ (the nitronium cation):
2H2SO4 + HNO3 → NO2
+ + H3O+ + 2HSO4
-
Nitrating mixtures are used to nitrate aromatic compounds (mainly a mixture of nitric and sulfuri
cacids) and unsaturated aliphatic compounds, as well as in the production of nitroaminocompoun
ds (nitramines) and nitro esters. Nitration is a general class of chemical process for the
introduction of a nitro group into an organic chemical compound.
Fig 8
In order to separate the final product that was 4-Nitrophthalic acid solvent solvent extraction
performed. Water was added into the reaction mixture about 20ml and then 20ml ethanol, two
distinct layers were formed. One of them aqueous and the other was organic. First remove the
aqueous layer by separating funnel and then organic layer added in beaker. left the beaker at
room temperature for two days to evaporate ethanol from the product . At the end light yellow
solid product of 4- nitrophthalic obtained
By the help of an already prepared solution of phthalic acid and newly prepared solution of
nitrophthalic acid(solid powder) perform TLC. Ethanol and methanol used as solvent. Rf value

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calculated. In this experiment TLC were perfomrd after every single step to check the reaction
progress wether the reaction successfully occured or not. Well TLC results indicated that the
product was form. As the spot of product and reactant were different affinity for the material on
TLC plate.
-With ethanol
Rf = 1/ 2.8
Rf = 0.35
-With methanol
Rf = 2/2.7
Rf = 0.74
Some factor that affects the Rf value are polarities of reactant and product, coating material on
pate and solvent used. As the polarity of the product was more thAn reactant, so it moves to a
larger distance than that of phthalic acid. The difference in distance traveled by phthalic acid and
4-nitrophthalic acid indicate that reaction occurred. During TLC tailing of the spot was
occurring due to some impurities in solvent or reacting mixtures. Rf Values for each solvent was
measured as methanol and ethanol.
Melting point of phthalic acid and nitrophthalic acid is 200◦C and 160◦C respectively. Melting
point is the clear indication whether the reaction occurred or not. Our initial reactant has the
melting point about 200◦C, after experiment the product was form its melting point observed
160◦C.
Percent yield was calculated by dividing the actual and theoretical yield and then multiply by
100.
% age yield = 0.6/0.7×100
= 0.76 ×100
= 76 %
The reason of this less percentage yield basically due to error or impuries. Some environmental
factors also affects the final product of reactions.
A mild, environmentally friendly method for reduction of aromatic nitro group to amine is
reported, using zinc powder and concentrated solution of hydrochloric acid. This procedure is
also a new method for the activation of zinc for electron transfer reduction of
aromatic nitro compounds. Some other reduction method may also be used instead of zinc and

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HCl mixture as The combination HSiCl3 and a tertiary amine enables a mild, metal-free
reduction of both aromatic and aliphatic nitro groups to amines. The reaction is of wide general
applicability and tolerates many functional groups.
M. Orlandi, F. Tosi, M. Bonsignore, M. Benaglia, Org. Lett., 2015, 17, 3941-3943
A well-defined iron-based catalyst system enables the reduction of nitroarenes to anilines using
formic acid as reducing agent. A broad range of substrates including other reducible functional
groups were converted to the corresponding anilines in good to excellent yields at mild
conditions. Notably, the process constitutes a rare example of base-free transfer hydrogenations.
G. Wienhöfer, I. Sorribes, A. Boddien, F. Westerhaus, K. Junge, H. Junge, R. Llusar, M.
Beller, J. Am. Chem. Soc., 2011, 133, 12875-12879.
Fig 9
As the product of this reduction reaction was not good, some other method of reduction my also
be applied to get batter yeild of reaction as mentioned above.
In process of extraction water added in beaker to dissolve the semisolid mass that was dark
brown in color. Ethanol was used as an organic solvent to produce a distinct layer. By the help of
separating funnel purify the product. Left the organic layer for 2 days, make sure the beaker
should be covered otherwise it will contaminate. Remember that eqeous layer should not discard
as may be the final product present in it. After 2 days when the beaker checked, the product was
extremely less from which the further experiment can’t continue so it should be necessary to
change the primary scheme of the experiment in order to start the reaction further.
TLC was performed for this experiment as the results showed that product formed. To check that
the reduction was occurring or not TLC is the best way to indicate. As the new product has a
different polarity from reactant that was 4-nitrophthalic acid and more polar than 4-
aminophthalic acid.
In a of mixture of 20% methanol and 80% ethanol
Rf = 1.9/ 2.1
Rf = 0.76

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Melting point of this reaction not measured because product was extremely small. However the
actual yield is very often smaller (the percent yield is less than 100%) for several reasons:
Many reactions are incomplete and the reactants are notcompletely converted to products. If a
reverse reaction occurs, the final state contains both reactants and products in a state of chemical
equilibrium.
Discrepency between the atcual and theoretical yield was due to following causes: the reaction
may not produced a stochiometric amount of product. This could be due to equilibrium, slow
rate decomposition of reactant. And evaporation. The reactants may not 100% pure. A common
problem in the synthesis is the issue of side reaction. One of the main reason is that during work
up , product becom discard.
Depending upon how these various factors, and others, play their role, the reaction, as written,
may or may not go to completion. In most cases the reaction does not go to completion. In this
case the mass of products formed (the actual yield) is less than the theoretical yield. A quantity
that describes this less-than-ideal yield is known as the "percent yield".
During the purification stage some of the product may be lost in distillation, or by
decomposition, or even evaporation. Some may remain inside the reaction, or purification
Temperature
The temperarure often has a tremendous influence on a reaction. The speed (or rate)
of a reaction usually increases with temperature.
Container
The vessel the reaction takes place in can also affect the reaction. The walls of the
vessel can enhance or retard a particular reaction.
Pressure
Gas pressure can also affect reactions.
Medium
The products that are formed in a chemical reaction can depend upon the medium,
e.g., in a water solvent versus a benzene solvent.
Physical
State Whether the reactants are in the gas, liquid or solid state can also influence the
course of the reaction.

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vessels, filtration systems, chromatographic columns etc. During a work-up which involve
solvent extraction or crystallisation some of the product is invariably discarded.The reaction may
not produce a stoichiometric amount of product. This could be due to equilibrium, slow rate,
decomposition of reactant, or product, or evaporation. The reactants may also not be 100% pure.
A common problem in synthesis is the issue of side-reactions producing an undesired product.A
number of persnol error occurs as If we spilled some of your sample, read a scale incorrectly,
forgot to tare the balance, etc.

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