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2. once the two pure melting points have been determined find a partner and together prepare 3 samples: one of 1:9 urea : cinnamic acid, one of 1:1 urea : cinnamic acid, and one of 9:1 urea : cinnamic acid. take the melting point of each of these mixtures. plot the graph of melting point vs. the composition of the sample. note: you can prepare a large batch of sample and share the materials among yourselves (take 10mg urea and 90 mg cinnamic acid for 1st sample and mix it together, ratio should be same).

Part ii. determination of an unknown substance

In this portion of the lab you cannot determine the identity of an unknown by comparing its melting point with the melting point of the three possible compounds. Mixing characteristics will be used instead to determine the identity.

1. Prepare three capillary tubes in the following manner. Take a piece of weighing paper and mix a small amount of the unknown with a small amount of the sample of diphenylacetic acid (1:1). Place this in a capillary tube. Then on a new piece of weighing paper, weigh a small amount of the unknown and mix it with a small amount of adipic acid. Place this in a capillary tube.

2.Place these three capillary tubes in the melting point apparatus and record in detail what occurs to each tube and at what temperature. Using this knowledge determine the identity of the unknown.

Experimental procedure for diels-alder

Cyclopentadiene dimerizes at ambient conditions. Because of this cyclopentadiene is purchased as the stable dimer dicyclopentadiene. In order to be of any use, the dimer must be cracked and distilled. Due to time constraints you will be given the cyclopentadiene that has been prepared by your TA.

Part iii. diels alder reaction

1.       Dissolve 0.20 g of powdered maleic anhydride in 1 mL of ethyl acetate in a test tube and then add 1 mL of petroleum ether. This combination of solvents is used because the product is too soluble in pure ethyl acetate and not soluble enough in pure petroleum ether.

2.To the solution of maleic anhydride add 200 mL (0.160 g) of cyclopentadiene and mix the reactants. Mixing can be accomplished by tapping the bottom of the test tube back and forth with your finger.

Safety: Be careful when injecting the cyclopentadiene into the test tube and make sure the test tube points away from you.

3.Crystals should begin to form, if no crystals begin to form scratch the inside of the tube with a pipette to initiate growth. The scratch marks on the inside of the tube often form the nuclei on which crystallization starts.

4.Should crystallization occur too rapidly at room temperature the crystals will be very small. If so, save a seed crystal, heat the mixture until the product dissolves, seed it and allow it to cool slowly to room temperature. You will be rewarded with large plate-like crystals.

5.Remove the solvent from the crystals with a pipette forced to the bottom of the tube. Wash the crystals with one portion of cold petroleum ether then again remove the solvent. Scrape the product onto a piece of filter paper, allow the crystals to dry in air, determine their weight, and calculate the yield of the product.

6.Take the melting point of the product.

7.Take and analyze an IR and NMR spectrum of your compound.

 Waste disposal

All capillary tubes are to be disposed of in the GLASS CONTAINER and NOT in the trash can!! Dispose organic substances in their proper containers.

Approximate lab time 2-2.5 hours

Report1: Diels-Alder and Melting Point(Total 30 points)

Here for the Report

Note: In preparing this report you are free to use references and consult with others. However, you may not copy from other students’work or misrepresent your own data (see honor code).

Name(Print then sign): ___________________________________________________

Lab Day: ___________________Section: ________TA__________________________

1. Draw the reaction and mechanism of maleic anhydride and cyclopentadiene. (4 points)




2. Show theoretical and percent yield calculations of the reaction between maleic anhydride and cyclopentadiene. (2 points)



3. What are the important IR frequencies and the functional group they correspond to? (2 points)


4. Analyze the NMR spectrum of the product. Draw the structure and assign each peak to the correct proton on the NMR spectrum. Are there any impurities? If yes, what are they? (4 points)

5. Write the major product of the following reactions with proper stereochemistry if required. (8 points)

Part 2: melting point (total 10 points)

1. Fill in the blanks: (5 points)

Melting Points of: Temperature in°C
Urea _________________________
Cinnamic acid _________________________
1:9 mixture _________________________
1:1 mixture _________________________
9:1 mixture _________________________

2. Draw a Plot of melting point versus composition of the mixture. (2 points)


3. Your explanation as to why your measured melting points do not match those in literature. (1 point)

4. Identity the unknown (Part II) product. (1 point)

5. Melting point of the DA product is: ____ (1 point)

Questions & Answers

How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
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Stoney Reply
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Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
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Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
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Damian Reply
absolutely yes
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it is a goid question and i want to know the answer as well
characteristics of micro business
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How can I make nanorobot?
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
how can I make nanorobot?
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
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Source:  OpenStax, Chem217labsfall07. OpenStax CNX. Oct 16, 2007 Download for free at http://cnx.org/content/col10463/1.4
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