Organic Chemistry I CHM 336 PRE-LAB 11 PDF

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Samantha Truckly (2654185) Pre-lab Assignment: Experiment Title: Diels Alder Reaction. Miniscale reaction of anthracene and maleic anhydride.

Statement of Purpose: Successfully synthesize chemicals through the Diels-Alder reaction. Reagents: CHEMICAL

STRUCTURE

MELTING POINT

BOILING POINT

HAZARD

DISPOSAL

215.76C

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Do no inhale or ingest, avoid skin and eye contact

Liquid organic waste

52.6C

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Do no inhale or ingest, avoid skin and eye contact

Liquid organic waste

Xylene

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138.4C

May affect central nervous system

Liquid organic waste

Hexane

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69C

May affect nervous system

Liquid organic waste

O

Anthracene HO

HO OH

Maleic anhydride

O

O

O

O

Procedure Outline: Part A: Microscale Reaction of 1,3-Butadiene with Maleic Anhydride 1. Place 200mg of 3-sulfolene and 90mg of maleic anhydride in a 5mL conical vial containing 250L of dry xylene. The vial should have an air condenser and spin vane. 2. Place drying tube filled with CaCl2 on the condenser. Heat the reaction mixture to reflux, with stirring, in a sand bath or heat block at 190C for 25 minutes. 3. Cool the mixture to room temperature then add 0.5mL of toluene and add petroleum ether dropwise until slight cloudiness remains. 4. Reheat mixture until it is essentially clear and then cool in an ice bath. 5. Collect white product by vacuum filtration using a Hirsch funnel and wash it on the filter with 1mL of cold petroleum ether. Determine percent yield. Part B: Miniscale Reaction of 2,3-Dimethyl-1,3-butadiene with Maleic Anhydride 1. Under the hood, pipet 1mL of 2,3-dimethyl-1,3-butadiene into a 10mL or 25mL round-bottom flask containing 0.88g of powdered maleic anhydride.

Samantha Truckly (2654185) 2. Fit the flask with an air condenser and drying tube containing CaCl2. The reaction will cause the flask to become warm, after about 20 minutes, the flask should have cooled to room temperature. 3. Remove the air condenser and drying tube then break up the solid mass in the flask with a spatula. 4. Add 5mL of ice-cold water and use the spatula to mix the solids with the water. 5. Perform a vacuum filtration to collect the solid on a Hirsch funnel. Then wash the solid with two additional 5mL portions of ice cold water and then two 2mL portions of ice cold tetrahydrofuran. 6. Air dry solid and weigh the product. Recrystallize from hexanes. Part C: Microscale Reaction of Cyclopentadiene with Maleic Anhydride 1. Place 200mg of maleic anhydride in a dry 5mL conical vial equipped with a water jacketed condenser or air condenser and drying tube. 2. Dissolve the anhydride in 0.75mL of dry ethyl acetate by warming in a sand bath or heat block. Then add 0.75mL of dry hexanes. 3. Cool the resulting mixture in an ice bath then add .20mL of freshly distilled cyclopentadiene and swirl the solution. 4. After the initial exothermic reaction is complete, a white solid will separate. Warm the mixture until the product is dissolved. 5. Cool the mixture and allow it to stand. Collect the white crystals of norbornene-cis-5,6-dicarboxylic anhydride by suction filtration using a Hirsch funnel and determine the yield. Part D: Miniscale Reaction of Cyclopentadiene with Maleic Anhydride 1. Place 2.0g of powdered maleic anhydride in a 50mL Erlenmeyer flask. Then add 5mL of dry ethyl acetate to partially dissolve the anhydride. 2. Warm the flask using a sand bath until all of the solids have dissolved. Then add 5mL of dry hexanes to the solution and cool the solution in an ice bath. 3. Slowly add 2.0mL of freshly distilled cyclopentadiene and swirl to mix. The solution will begin to warm, soon a white solid will begin to precipitate. 4. Cool the mixture in an ice bath and allow to stand. Collect the solid product of norbornene-cis-5,6dicarboxylic anhydride by suction filtration using a Buchner funnel and allow to air dry. Weigh the dry product. Part E: Miniscale Reaction of Anthracene with Maleic Anhydride 1. Add 0.89g of anthracene and 0.49g of powdered maleic anhydride to a 25mL round-bottom flask containing a stir bar. 2. Add 12mL of dry xylenes and fit the flask with a water-jacketed or an air condenser and a drying tube. Position the flask on a heat block or place in a sand bath or heating mantle and reflux with stirring for about 30 minutes. 3. Cool to room temperature, some solids may appear upon cooling. Dissasemble the apparatus and place the flask in an ice bath in order to allow more solid to accumulate. 4. Suction filter the product using a Buchner funnel and wash the solid on the filter with 1-2mL of cold xylenes. Allow to air dry on filter. 5. Scrape the product onto a new piece of filter paper and allow to air dry. When dry, weigh the product. Reflux Apparatus: View attached. Citation: Mayo, D. W.; Pike, R. M.; Trumper, P. K.; “Microscale Organic Laboratory with multistep and multiscale synthesis”, 5th ed., John Wiley & Sons, N. Y., 2000, page 269. ISBN:0-471-21502-3 Mohrig, J.R.; Alberg, D.G.; Hofmeister, G.E.; Schatz, P.F.; Hammond, C.N.; Laboratory Techniques in -Organic Chemistry; Freeman, New York, 2014, 87-9; 132-140; 255-269.

Samantha Truckly (2654185) Pre-lab questions: 1. (2 point) Consider the equation for the reaction in this experiment:

Calculate the potential yields of the product (in grams) for anthracene and maleic anhydride. From these potential yields, identify the limiting reagent and theoretical yield. Molecular weight of anthracene: 178.234 gm/mol Molecular weight of 9,10-Dihydro-anthracene 9,10, alpha, bita -succinic acid anhydride: 276.3 gm/mol 1 mol anthracene =1 mol 9,10-Dihydro-anthracene 9,10, alpha, bita -succinic acid anhydride Assuming 1 gram anthracene + 1/2 gram maleic anhydride gives = 9,10-Dihydro-anthracene 9,10, alpha, bita -succinic acid anhydride, maleic anhydride is the limiting agent. Molecular weight of maleic anhydride = 98.06 gm/mol, so 0.5 mol maleic anhydride =1 mol product Molecular weight of maleic anhydride/Molecular weight of product = 276.3/(98.06*2) = 1.408 = theoritical yield. (1 mol maleic anhydride) = (1.408*2)-1.55 = 1.2 = actual yield [ (1.2/1.408 )* 100 ] = 85.23% = percent yield 2. Question 5 of handout

a)

+

=

b)

+

=

Samantha Truckly (2654185)

c)

+

=

3. Question 6 of handout A chiral compound contains up to four chiral centers with relative and absolute configurations. Their synthetic potential is created with the addition of hydroxyl acids, monoterpenes, steroids, amino acids, and sugars. Chiral natural products can be synthesized by using Diel's Alder Reaction. 4. Question 7 of handout A trans-diene cannot undergo diels-alder reaction, therefore the diels-alder diene must be cis-diene....