Chem 361 lab 4 PDF

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Summary

Preparation of Cinnamic acid...

Description

Daood Tanvir Gill (20-11214)

Experiment # 4 Preparation of Cinnamic Acid from benzaldehyde and malonic acid (Knoevenagel Reaction)

Materials Malonic Acid

Benzaldehyde

Round Bottom Flask

Spatula

Heating Mantle

Ice water

Filter Paper

Beaker

Weighing Balance

8% Ethanolic Ammonia Solution

Pipette

Reflux condenser

Ice bath

Dilute HCl

Funnel

Procedure 1. Weigh 2g of malonic acid and put in the round bottom flask. 2. Add 2 mL of benzaldehyde to the flask. 3. Then add 10 mL of 8% ethanolic ammonia solution . 4. Mix well until all the malonic acid is dissolved. You should get a cloudy solution. 5. Reflux on heating mantle at 150 o C. CO2 will be evolved. 6. Wait till all the CO2 has evolved (approximately an hour) and then remove from heating. 7. Cool till room temperature, then add approximately 50 mL of ice water to the solution. Chem 361 Lab Report

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Daood Tanvir Gill (20-11214) 8. Add few drops of dilute HCl and constantly stir. Place in an ice bath. Precipitates should form. 9. Filter the solution. Then dry and weigh.

Chemical Equation

Chem 361 Lab Report

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Daood Tanvir Gill (20-11214) 8% Ethanolic Ammonia

Dilute HCl

(Since, Benzaldehyde is the limiting reactant)

Benzaldehyde

:

Cinnamic Acid

Mole Ratio

1

:

Molar Mass

106.12 g / mol

:

2.08 g

:

Given

1 148.16 g / mol xg

Theoretical Mass =

(2.08 x 148.16) / 106.12

=

2.90 g

Obtained Mass = 1.91 g

Percentage Yield = (Obtained / Theoretical) x 100 = (1.91 / 2.90) x 100 = 65.86 %

Mechanism Chem 361 Lab Report

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Daood Tanvir Gill (20-11214)

Cinnamic Acid

Chem 361 Lab Report

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Daood Tanvir Gill (20-11214) Uses of Cinnamic Acid Cinnamic acid is used in flavorings, synthetic indigo, and certain pharmaceuticals. A major use is in the manufacturing of the methyl, ethyl, and benzyl esters for the perfume industry. Cinnamic acid is a precursor to the sweetener aspartame via enzymecatalysed amination to phenylalanine.

Precautions      

Wear a lab coat to avoid spilling of chemical on the body. Use gloves for the handling of apparatus; some of the chemicals might be corrosive or skin irritating. Do not inhale the fumes. Cover the face with a mask. These fumes might cause respiratory problems. Handle the reflux carefully. Once reflux has been done allow it to cool for some time. Touching directly can cause skin burn. Properly dispose the waste chemicals. If any chemical falls on the body, rinse immediately with water and contact your professor or lab supervisor. Seek for medical assistance.

Chem 361 Lab Report

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