lab

Lab-10

VCL 10-1: Grignard Addition-1

By: Michele Hopkins

Ocean County Community College

Chemistry 284

Virtual Chemistry Lab-Organic

03/21/15

Table of contents

Title Page……………………………………. Page 1

Table of Contents…………………………Page 2

Abstract………………………………………. Page 3

Introduction………………………………....Page 3

Experimental Details …………………..Page 4

Results ……………………………………….Page 5

Discussion………………………………….Page 6-7

Conclusion and Summary ………….Page 8

References…………………………………Page 9

Abstract

This lab is used to show how to determine when a reaction has reached completion. For this assignment, the target compound that you should synthesize is 1-phenyl-1-propanol. This is an organometallic addition reaction. Examine the product and identify potential bonds that may be formed. Keep in mind the mechanism and the need to quench the reaction with acid to liberate the neutral product. This lab focuses on determining this using a TLC test, which is performed several times during the reaction. The TLC is also performed using organic material formed. This lab primary goal is to teach about TLC test, reaction completion, NMR, as well as the IR Spectra and to teach organic chemistry students some basic chemistry principles as applied in this lab.

Introduction

The purpose of this lab is to prepare a demonstration of the Grignard Addition. I should be able to notice the outcomes of the change in structures on the reaction results.

Experimental Data

1. The starting materials were obtained from the stock room

a. Round Bottom Flask

b. (PhCHO) Benzaldehyde

c. (EtMgBr) Ethyl Magnesium Bromide

d. H2O

2. The PhCHO and EtMgBr were added to the flask

3. The flask was placed on the stir plate

4. Water (H2O) was added to the flask along with the other starting materials

5. The stir Plate was turned on and the reaction started

6. A TLC measurement was done at the begin of the reaction

7. A TLC test was done 10 minutes after the reaction had begun

8. Various TLC test were on at different time intervals as to record when the reaction came to completion.

9. The reaction mixture was added to a separatory funnel

10. H2O aqueous reagent was added to the funnel

11. Two thin layers of organic and aqueous phase were observed in the funnel

12. A TLC measurement was performed on the organic layer in the funnel 1-phenyl-1-propanol

13. All lab materials were cleaned up and put away

14. How long did it take to finish the reaction? 1 hour and 50 min.

15. What are the TLC values (Rf) for (a) starting Materials: (b) Products:

16. Write a mechanism for this reaction:

17.

Results

TLC Measurement – Stirred Mixture

04:09 (Start of Reaction) 04:19 04:49 05:49 (complete)

TLC Measument- Funnel Organic TLC –Stired Complete vs. Organic

Organic Stired Organic

IR Spectra

After completing a reaction and working up the products, it is still necessary to confirm that the correct

product was formed. The most common tools used for this analysis are Infrared (IR) and Nuclear

Magnetic Resonance (NMR) spectroscopy. In the virtual laboratory, only 1H NMR spectra are available.

Details on interpreting IR and NMR spectra are found in your textbook. Your instructor may or may not

ask you to perform this section depending on how your class is structured.

To collect an IR spectrum of your product, click on the IR spectrometer located underneath the

laboratory clock and drag the salt plate icon to the flask on the lab bench. A window containing the

IR spectrum for your product should now open. Identify the relevant peaks in the IR spectrum and

record the position and associated functional group for each in the IR table below. The IR spectrum

can also be saved to the lab book for later analysis.

IR List Position (cm-1) & functional group	4.
1.	5.
2.	6.
3.	7.

To collect a 1H NMR spectrum of your product, click on the NMR magnet located to the right of the

chalkboard and drag the NMR sample tube to the flask on the lab bench. A window containing the

NMR spectrum for your product should now open. You can zoom into various portions of the NMR

spectrum by clicking and dragging over the desired area. The Zoom Out button is used to zoom back

out to view the full spectrum. Identify all of the peaks in the NMR spectrum and record the chemical

shift, the splitting, and the number of hydrogens for each peak in the NMR table below. The NMR

spectrum can also be saved to the lab book for later analysis.

1H NMR	Peak	Chemical Shift(δ)	Multiplicity†	H‡	Peak	Chemical Shift(δ)	Multiplicity†	H‡
	1				7
	2				8
	3				9
	4				10
	5				11
	6				12

†Specify the multiplicity as a singlet (s), doublet (d), triplet (t), quartet (q), or multiplet (m).

‡Specify the number of hydrogens associated with each peak.

Do the IR and NMR spectra you measured and recorded in the tables above confirm that you

synthesized the assigned target compound? Explain

Conclusions and Summary

References

Adapted from E. Boschmann & Norman Wells, Chemistry in Action: A Laboratory Manual for General, Organic, and Biological Chemistry, 4th Edition, page 309.

Clark, J. (2004). INTRODUCING ESTERS. Retrieved from http://www.chemguide.co.uk/organicprops/esters/background.html

Organic Chemistry, Seventh Edition, Paula Yurkanis Bruice

Organic Qualitative Analysis- Amines. (2013). Retrieved from

http://faculty.swosu.edu/william.kelly/pdf/qo10.pdf

Virtual Chemistry Lab: Organic

Virtual ChemLab v2.5 Organic Synthesis and Organic Qualitative Analysis- Laboratory Workbook Student Manual

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