activity of acetylsalicylic acid essay

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Synthesis of Acetylsalicylic Chemical p Essay

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Biochemistry and biology

Acetylsalicylic Acid solution (Aspirin) Activity

Telow, AJV

Sumicad, CJ, Tavanlar, EMMT, Chem forty five. 1, Commence of Biochemistry, University with the Philippines Los Baños

We. Introduction

Organic synthesis is the method where a ideal organic chemical substance is made or well prepared from commercially available materials. The goal of organic activity is to design the simplest artificial routes into a molecule. Aspirin, also known as acetylsalicylic acid can be as salicylate medication often used since analgesic to relieve minor pains and aches, as an antipyretic to lower fever, and as an anti-inflammatory medication.

The history of aspirin and its medical use can be tracked way back in the secong millenium BCE. Drugs from willow and other salicylate-rich plants can be found in the Egypt pharonic pharmacology papyri. During 400 BCE in Greece, Hippocrates provides women willow tree tea leaf to relieve the pain of childbirth. This individual also utilized salicylic tea to reduce fevers. Willow bark extract then became praised for its efficiency in minimizing fever, discomfort and irritation in the mid- eighteenth 100 years.

By nineteenth hundred years, pharmacists had been experimenting with and precribing a variety of chemicals associated with salicylic chemical p, an active element of willow get.

In 1853, chemist Charles Frédéric Gerhardt treated acetyl chloride with sodium salicylate to produce acetylsalicylic acid the first time; in the second half of the nineteenth century, additional academic chemists established the compound’s chemical structure and devised more efficient methods of activity. In 1897, scientists at the drug and dye organization Bayer started out investigating acetylsalicylic acid being a less-irritating replacement for standard prevalent salicylate drugs. Aspirin was initially isolated by Felix Hoffmann, a chemist in the The german language company Bajuware (umgangssprachlich). By 1899, Bayer acquired dubbed the pill Aspirin and was offering it around the world.

The word Aspirin was Bayer’s brand name, rather than the generic identity of the medicine; however , Bayer’s rights towards the trademark had been lost or sold in many countries. Aspirin’s popularity grew over the initial half of the 20th century, spurred by its effectiveness In the wake of Spanish flu pandemic of 1918,  and aspirin’s profitability led to intense competition plus the proliferation of aspirin brands and goods. Some of the 1918 flu deaths were probably due to Acetylsalicyls�ure poisoning.

Aspirin’s popularity dropped after the advancement acetaminophen/ paracetamol in 1956 and ibuprofen in 1962. In the 1960s and 1970s, Ruben Vane and more discovered the standard mechanism of aspirin’s effects, while trials and other research from the 60s to the eighties established aspirin’s efficacy as an anti-clotting agent that reduces the chance of clotting disorders. Aspirin product sales revived noticeably in the last many years of the 20th century, and remain solid in the twenty-first with widespread use being a preventive treatment for center attacks and strokes.

Inside the preparation aspirin, salicylic acidity is responded with too much acetic anhydride. A small amount of a solid acid is used as a catalyst which boosts the reaction. With this experiment, phosphoric acid to be used as the catalyst. The excess acetic acid will probably be quenched with the addition of water. The aspirin method not very sencillo in drinking water so the aspirin product will precipitate the moment water can be added. The synthesis reaction of aspirin is definitely shown below:

II. Objectives

This kind of laboratory physical exercise aims to:

1 . to synthesize acetylsalicylic acid coming from salicylic acidity by nucleophilic acyl replacement; and 2 . to describe and explain the differences in the houses of acetylsalicylic acid and salicylic acidity by straightforward chemical tests.

III. Methodology

A. Schematic Picture

one particular gram salicylic acid in 125-mL Erlenmeyer flask

+ 3-mL acetic anhydride + you drop 85% phosphoric acid solution


– heat in steam bath to get 15 minutes

& 2-mL dH2O

+ 20-mL ice cold H2O

-cool to RT

-place in an ice bathroom

-perform suction purification

residue filtrate

— wash many times — transfer crystals to pre-weight observe glass air dry  weight dried aspirin calculate % yield crude aspirin set aside small quantity pertaining to MP determination transfer the rest to 125-mL Eflask

& 95% ethanol dropwise swirl until almost all dissolves

+ cold dH2O dropwise until almost all uric acid appear cool flask within a cool bath suction filtration  calculate % recovery


remains filtrate wash crystals with tiny portions of cold H2O – transfer crystals to pre-weight watch goblet air dry weight dry aspirin calculate % recovery transfer aspirin to vial label determine the MP of crude and  recrystallized aspirin


Characterization of Aspirin:

Response with KMnO4:

a few drops dilute, slightly acidic KMnO4 in test tube

& pinch with the sample

– warm the pipe in drinking water bath pertaining to 5 minutes. – look at mixture

Effect with FeCl3:

crunch of the sample in check tube

+ several drops 2 . 5% aqueous FeCl3

+ 1-mL dH2O

– analyze mixture

Differentiation of the synthesized acetylsalycylic chemical p from is sold aspirin:

pinch of the test test pipe

& 5 drops H2O

— replicate process although add your five drops iodine solution

instead of H2O

B. Set-ups

Figure 10. 1 . Suction filtration set-up

C. Chemical Data Piece

Stand 11. 1 Chemical data sheet intended for the synthesis of acetylsalicyls�ure

Identity and framework of the reactants

Features in the workout

Physical properties



salicylic acidity

Starting material a white powder-like substance with an MEGAPIXEL of 159°C and a density of just one. 44g/cm3 Pores and skin and eye irritants In circumstance of get in touch with, immediately flush skin with plenty of water acetic anhydride

Converts salicylic acid’s hydroxyl group in an acetyl group a colorless liquefied with a denseness of 1. 08 g/cm3 Corrosive and flammable Keep faraway from heat. Have on gloves, eye protection and face security phosphoric acidity

Serves as the catalyst a clear viscous liquefied with a density of 1. 88 g/cm3 and a cooking food point of 158°C Extremely corrosive

Avoid direct contact. Wear chemical safety clothing

95% ethanol

Used for the recrystallization a colorless liquid having a melting point of 114°C and a density of 789. 00kg/m3 Skin and eyes irritants. Long term employ can lead to serious lean meats damage Steer clear of heat. Use gloves, vision protection and face protection KMnO4

Differentiating agent a crimson liquid

Highly forceful when responded with focused sulfuric acid In case of speak to, immediately get rid of skin with plenty of drinking water for at least a quarter-hour FeCl3

To get the characterization of the produced aspirin and commercial acetylsalicyls�ure Brown water with a molar mass of 162. 20g/mol, a boiling point of 306 °C and a density of 2. 9g/mL Rust, toxic and acidic

Eliminate skin with water in case there is direct contact

IV. Info

Stand 11. installment payments on your Description of reagents


DESCRIPTION salicylic acid white, powder-like substance acetic anhydride clear liquid with strong odor phosphoric acid clear, colorless liquid with strong odor 95% ethanol clear, colorless water with strong odor KMnO4  purple liquid FeCl3 brown liquid Iodine solution clear liquid

Table 11. 3. Prep of Acetylsalicyls�ure



Salicylic acid & acetic anhydride + 85% phosphoric chemical p

salicylic acid was dissolved

Mixture in room temperature crystals were shaped

Blend after ice cubes bath more crystals were formed

Suction Filtration:  residue filtrate


fine, white crystals

clear water with small amounts of crystals at the bottom

Crude aspirin

great white deposits

Table eleven. 4. Recrystallization of Aspirin


Crude aspirin + ethanol

mold of most uric acid occurred

Mixture during cooling

crystals were formed

Mixture after cooling

more uric acid were produced

Suction Filtration:



great, white crystals

obvious liquid

Desk 11. a few. Recovery info of recrystallized aspirin


Excess weight of enjoy glass + filter daily news (g)

1 . 355

Fat of enjoy glass & filter newspaper + merchandise (g)

2 . hundratrettiofem

Weight of product (g)

0. 780

Theoretical yield

1 . 300

% yield


% restoration


Table eleven. 6. Shedding point dedication



Crude aspirin


Recrystallized aspirin


Table 11. six. Differentiation of starting materials from the merchandise TEST




disappearance of violet color and creation of darkish precipitate the perfect solution remained crimson


the perfect solution remained brownish and not all the sample blended the solution started to be darker color of dark brown and not each of the sample blended

Table 10. 8. Difference of synthesized acetylsalicylic acid solution from commercially-available aspirin simply by iodine check SAMPLE


Synthesized acetylsalicylic acid

all of the test dissolved plus the solution can be turbid

Commercially- offered aspirin

all of the test dissolved plus the solution can be turbid

Sixth is v. Sample Computations

1 . 0g SA ( 1 mol SA/ 138. 16 g) ( one particular mol ASA/1 mol SA) ( one hundred and eighty. 21g/ you mol ASA) = 1 . 30g

3. 00 milliliters AA ( 1 . 08g AA/ 1mL)( 1 mol AA/ 102. 11g)(1 mol ASA/ one particular mol AA) (180. 21g/ 1 mol ASA) = 5. 72g

% yield = Genuine yield/ Theoretical yield Back button 100%

= 0. 78g/ 1 ) 30g X 100% sama dengan 60%

% recovery = Recovery deliver / Actual yield By 100%

= 0. 457g/ zero. 78g Back button 100% = 59%

MIRE. Results and Discussion

In this exercise, the target was to produce acetylsalicylic chemical p through the organic and natural synthesis from your reaction of salicylic acid to acetic anhydride, the starting materials. Instead of using acetic acid, acetic anhydride was used while solvent considering that the anhydride re-acting with drinking water to form acetic acid tends to travel the reaction for the right. It results from the elimination of a molecule of water via two elements of lactic acid (see Fig. 11. 2). Figure 10. 3 under shows the balanced chemical reaction of the activity of acetylsalicylic acid.

Figure 11. 2 . Structure of Acetic Anhydride

Figure 14. 3. The balanced reaction of the development of aspirin.

Because the response is slow in pure acetic anhydride, the catalyst, commonly solid acids like phosphoric acidity was used pertaining to the reaction. According to Votre Chatelier’s theory, the presence of surplus acetic anhydride forces the equilibrium towards the desired merchandise, which in this situatio is the acetylsalicyls�ure. In addition to this, the catalysts were also used to make sure that side reactions, which may trigger the percentage produce to increase, will be avoided.

The reaction behind the synthesis is nucleophilic acyl substitution. In accordance to McMurry (2000), nucleophilic acyl substitution happens when the initially created intermediate expels one of the substitutes originally attached to the carbonyl carbon resulting in the formation of any new carbonyl compound. With this experiment, the actual nucleophilic acyl substitution is definitely esterification. That occurs if a carboxylic acidity in salicylic acid and an alcoholic beverages combine in a reaction to produce an ester.

Figure eleven. 4. Mechanisms on the creation of acetylsalicyls�ure

Phosphoric acid protonates the carbonyl oxygen atom (C=O) of the anhydride to make it even more prone to nucleophilic attacks. It provides the anhydride a positive demand thus, so that it is more at risk of nucleophilic disorders. The nucleophilic hydroxyl selection of salicylic acidity attacks the electron lacking acetic anhydride resulting to a tetrahedral intermediate. The hydroxyl group (-OH) attached to the electrophilic carbon dioxide removed the hydrogen as proton therefore donating the electron to form a double relationship (C=O). Loosing the proton regenerates the phosphoric acidity and thus, producing acetylsalicylic acid solution.

To enhance the synthesis effect, addition of heat and drinking water after heating system were performed. The synthesis of reaction is well-liked by heating the mixture as it speeds up the dissolution technique of salicylic chemical p and raises its solubility as well. As this specific effect is an endothermic method, addition of warmth would favour a forwards reaction bringing on the formation of products. Aside from that, nucleophile was entirely facilitated by the addition of water following heating. Drinking water was used to supply medium for further nucleophilic replacement.

The theoretical yield attained is 1 . 30 grms after knowing that salicylic acidity is the constraining reagent. Using the yield attained is 0. 78 grms thus, the % deliver is 60 per cent. This results are relatively low because of likely sources of mistake such as loss of product in the filter daily news because of continuous air perishing, decomposition to acetic acid in solution therefore there was not a complete transformation of reactants and too little heating.

After obtaining the crude aspirin, recrytallization was performed. This is performed to remove the traces of impurities. Following cooling to room temp and dipping on an ice cold water bathtub, suction filtration method was done to distinct the filtrate from the residue which contains the recrystallized items. Suction purification is the most useful technique to employ when fast filtration of mixture is definitely desired. This employs cleaner which can promote passage of filtrate through the filter conventional paper (Basic Organic Chemistry: Clinical Manual, 2012). In addition , as aspirin is usually an ester, it should not really be recrystallized from hot water because it allows the

crude test to be hydrolyzed and yield undesirable items. The % recovery attained is 59%.

After performing the activity of aspirin from salicylic acid, the verification from the identity and purity with the product through melting stage determination was also performed.

In distinguishing salicylic chemical p from the synthesized product, FeCl3 test and KMnO4 test were conducted. To get the FeCl3 test, the positive will give a big change from yellow-brown solution to a violet coloured complex. For this test, in this way positive due to presence of phenol in it. The oxygen atoms of the acid solution group –COOH, and of the -OH group on the salicylic acid jointly can form a fancy with Fe(H2O)6 +3. Quality result on aspirin is definitely negative since iron complicated cannot be created due to the a shortage of a hydroxyl group attached with benzene.

To get the KMnO4 test, a positive result was obtained from the synthesized aspirin as noticed by the disappearance of purple color and formation from the brown medications. Theoretically, salicylic acid would give a positive effect because of the existence of hydroxyl group (-OH). Recalling the reactions in alcohols, KMnO4 was used to detect the existence of primary and secondary alcohols. Since the phenol group is usually absent in the synthesized acetylsalicyls�ure, a negative consequence should be obtained.

Another test was conducted to identify the produced apirin from the commercially-available acetylsalicyls�ure. Unfortunately, same results was obtained from both samples. Essentially, the commercially-available aspirin will give the positive response to the solution turning blue or perhaps violet because of the presence of strach for the commercially-available aspirin because pharmaceutical companies put starch to tablet medications to give these people its attribute shapes. And the iodine test is use for detect arsenic intoxication starch in a sample.

Finally, the melting point determination was done. One way of figuring out a material is through its melting point. The number of the shedding point can provide one an thought on the purity of the sample. The theoretical melting point range of aspirin is definitely 128-137°C. In this experiment, the obtained shedding point array of of the raw aspirin is usually 106- 112°C and for the recrystallized acetylsalicyls�ure, it is 114-118°C. The effects of burning point willpower means that the samples include impurities in it. Slim difference in the melting level range of the sample and the theoretical melting point range means that the substance is pure because of the uniform forces present in the molecules. When the range is wide, this means that the test contains pollutants. In this work out, melting level determination is carried out. And the results show that it comes along with a wide big difference from the assumptive melting point range of acetylsalicyls�ure. Thus it is usually inferred through the results the fact that sample is not real.

VII. Synopsis and Bottom line

Activity of organic compounds entails guidelines and steps that ought to be followed. The first one is the organization of the starting materials which is in this are definitely the salicylic acidity and acetic anhydride along with the phosphoric acid that served as the catalyst intended for the reaction. The synthesis of aspirin included the acid-catalyzed nuclephilic acyl substitution. The specific nucleophilic acyl substitution for this experiment is definitely esterification. It occurs when a carboxylic acid from your salicylic chemical p and a great alcohol combine in a effect therefore creating an ester. In this test, phosphoric acid solution was used like a catalyst to hasten the reaction between the salicylic acid and acetic anhydride.

Heat and addition of water was also carried out for effiecient production in the desired item. The percent yield received for this try things out is 69%. Low %yield can be brought on by insufficient warming and that the merchandise was lost in the filtering paper due to prolonged air drying. The next step that was completed was the recrystallization of the elementary sample to obtain a more filtered organic mixture. Recrystallization was done by suction filtration. The very last step with this experiment is a verification and differentiation in the samples. Through the KMnO4 test, it was confirmed that the produced product was indeed being acetylsalicylic acidity or most commonly known as acetylsalicyls�ure. Other checks such as iodine test and FeCl3, unfortunately did not give the assumptive results.

VIII. References

Aspirin schedule. (2013). Recovered on October 5, 2013 from

History of Aspirin. (2013). Gathered on March 5, 2013 from

Institute of Chemistry. (2012). Basic Organic and natural Chemistry Lab Manual. School of the Korea Los Banos College Laguna. 72-75.

Material safety data sheet. (2013). Retrieved in October 6, 2013 coming from

MSDS for potassium permanganate. (2013). Retrieved upon October 6, 2013 from

McMurry, John. (2000). Organic Biochemistry and biology. 7th Release USA.

Phosphoric acid. (2013) retrieved on August 6, 2013 from

Rodriguez, Electronic. B. (1997). Basic Principles of Organic Biochemistry and biology. UP Wide open University: Diliman Quezon Metropolis. 295 – 336.

IX. Remarks and Recommendation

The synthesis of organic compounds is indeed very helpful in chemistry and through this method, one can have got a peek on how chemical processes works in real life. The investigator recommends the usage of other tests in order to obtain more accurate results in the differentiation of the produced aspirin from the commercially-available acetylsalicyls�ure.


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