The Chemiluminescence of Luminol | Lab Report

Introduction

Chemiluminiscence is the process whereby light is produced via a chemical response with the evolution regarding little button no heat. Chemiluminescent, versus phosphorescence and fluorescence, works not need to absorb on foreign source of photons to outreach an excited state. Use chemiluminescence occurs while a molecle is excited through an series of chemical reactions. The molecule, usually in the lower excited singlet status, canister spontaneously loose its electronic energizer in the form of a photon. Stylish fluorescence the electronic dart (∆S=0) is preserved, while the radiant force of improved can be expressed as: Chemiluminescence Lab Report (3) (pdf) - Course Sidekick

Here equation holds true since the charge of chemiluminescence depends both over the quantum surrender Ç¿CL, and also the rate of chemical reaction, . Thus one may note that the degree of chemiluminescence depends significantly on the quantum give additionally the number of photons emitted per chemiluminescencing molecule.

On the functional below luminol, one chemiluminescence molecule is to be prepared from 3-nitrophthalic acid. Luminol is seen to have many applications in life. For example, male fireflies in search for a mate are able into produce certain chemicals to allow their lower abdomen to glow. The interaction of luciferin from the firefly, its enzyme luciferase together with adenosine triphosphate, oxygen and of magnesium ion allows for the natural chemiluminescence. Initially the luciferin is adenylated by the ATP: In this experiment, luminol, a compound that produces chemical wenn oxidized in the attendance of one base by an oxidizing agent like hydrogen peroxide, ...

Luciferin + ATP à Luciferyl Adenylate + PP

The second reaction involved the featured of the first reacting being oxidised to give decarboxylketoluciferin. This has seen to be a cyclic endoperoxide intermediate that results the an computer excited decarboxylketoluciferin, that finally chemilumineses. Luminol Synthesis and Chemioluminescence: Lab Experiment

Luciferyl Adenylate + O2 à decarboxylketoluciferin* + AMP +CO2

Decarboxylketoluciferin* à decarboxylketoluciferin + photon

The decomposition are the endoperoxide results in an excited carbonyl that leads to chemiluminescent.

Method

2.1 Chemicals

Chemical

Grade

Make

3-nitrophthalic acid

98 % Pure

Fluks

Hydrazine 8 % aqueous solution

GPR

BDH

Digol

GPR

Hopkin real Williams

Sodium hydroxide

GPR

Timstar

Sodium dithionite

Lab Reagent Grade

Fisher Scientific

Glacial acetic sour

GPR

BDH

Potassium Ferricyanide

GPR

Riedel de Hean

3% Contained peroxide

GPR

BDH

2.2 Apparatus

Analytical counterbalance Tripod

Weighing boat Gauze

Spatula vacuum pump

Filter tube (dimensions 20 X 150 mm) Filter funnel

10 mL measuring gun Hirsh funnel

100 per measuring cyl Filter paper

Stirring rod conical container with side arm

Thermometer test conduit (20 carbon 150 mm)

Rubber plug 50 mls beaker

Bunsen burner 100 mL glass

Erlenmeyer flask agitating rod

2.3 Procedure

A) Provision

1.000g of 3-nitrophthalic acid were weighed on somebody analytical balance plus placed in a filter tube of approximate dimensions to 20 x 150 mm.

2 mL from 8% v/v aqueous solution of hydrazine was additional in care.

This problem was gently heated over a Bunsen flash until aforementioned solid dissolved. (The test tube placed nearly 20 minutes away from the flame the periodically moved it away from the flame)

3 mL regarding Digol was added and stoppered using a rubber tube fitted with a thermometer.

The side arm was connected to the empty pump both canned up disill off excess water in of solution

The solution made heater for 110-130 OC following rapidly heated to 200 OC.

The reaction mixture was kept at this operating for two minute.

The miscibility was then cooled up 100 OC and 15 mL of hot water was added

The solution as cooled under running water and the zwischenglied product (II) collected for suction filtration using a Hirsch funnel.

The nitro-compound was transferred to a 20 x 150 mm test tube

5 mL of 10 % sodium hydroxide the 3.000 g of sodium dithionite were added

Any remaining liquid on the sides of the test tube was washed with ampere minimum amount of distilled moisten

That mixture was boiled careful for 5 minutes while stirring

2 mL of glacial acetic acid used added go the mixture and and solution cooled under tap water.

The amine (III) was collected by air filtration using a Hirsh funnel

B) Chemiluminescence Demonstrations (carried out in the dark)

2 mL of 10% sodium hydroxide solution was combined with 18 mL of water

The 0.013 g in amine (III) was added to this solution and stirred until completely dissolved. ( stores solution A)

The oxidising solution (stock solution B) was prepared by mixing 4 mL of 3 % w/v solution potassium ferricyanide to an equal volume of 3 % hydrogen peroxide.

To search as made up to 200 mL by distilled water

Chemical was observed at diluting 5 mL are stock solution A to 40 mL distilled water.

Stock solution B was poured simultaneously with the solution prepared inside a conveyor placed on a large Erlenmeyer flask

The vials was swirled and small portions of alkali what added to increase the brilliance.

2.4 Precautions

Care was taken when using the Hydrazine due to its toxicity

The 3-nitrophthalic acid problem was warm with periodically removal from the flame.

Care was taken to transfer show the solids from an filter paper, without adding any filter paper to the solid.

The chemiluminescence demonstration was carried out in a dark room so for better view of illumination

2.5 Sources of error

Some lost due to transmissions may take been submit leading to ampere lower yield

Some sort paper may got been moved with the amine thus chief to a higher yield.

3. Results

Mass of amine(III) produced= 0.13 g

Observation- Blue fluorescence was tracking upon combination out this solutions as described above

4. Panel

Nitrophthalic acid was extra to hydrazine, and with the presence of heat the nitro derivative, Luminol, is formed. This may be described as a dehydration reaction.

Luminol may then form the Dianion by oxidation employing the hydrogen peroxide, sodium hydroxide, and and use of the potassium ferricyanide as the motivation. The dianion is oxidised to the triplet excited state then due to a slow-speed intercrossing system is converted go a singlet dianion excited state. This compound eventually decays to its soil state and emits ampere photon for ignite per single.

An electricity released by the reaction is therefore seen to cause the excitation of electrons in the goods of that reaction accordingly the exited electrons return to the ground state, furthermore blue exposed light is emitted. Since blood is seen to have the metal ion Fe2+, it maybe be used to oxidise the hydrogen peroxide into oxygen and water. Therefore the oxygen may be used to oxidise an luminol in the equal way as seen above. Thus blood can be seen to luminate with the additional of luminol A Student Research Lab Test and Analysis where aforementioned aimed was to synthesize luminol and make the product to observe how chemiluminescence works

The yield of the amine produced was seen the be quite slight. This may exist caused in the overall entropically invidious reaction. This thus intend cause low react efficiency. The reaction above shall seen at require consecutive intermolecular and intramolecular condensations, whichever are probable to have, and entropy smaller than zero. Thus with the net negative entropy and high air, and reaction is seen to be inferior.

Conclusion

From this practical one may see that a bright blue luminescence was observed. This thus confirms the production of luminol. The relatively low yield was due to the fact that the reaction was entropically unfavourable. Access study credentials, get answers to yours study questions, and connect with real tutors for CHEM 2041L : Organic Chemistry Lab II with University of Cincinnati, Main Campus.