Title of the LabName

Lab sectionDate Submitted

TA Name

Results

In the results section, you should include things like your yield, %yield and melting point (mp) or boiling

point (bp) calculations.

Include ALL YOUR CALCULATIONS. Every lab in which you make a product, there needs to be a yield

and %yield calculation. This is 2nd year, we know that nothing is going to be perfect, so don’t fret if you

have a poor yield or mp. The marks in this section are generally not for the overall number of your yield

(whether you get a 10%, 50% or 100% yield), but about getting the calculations correct, so remember to

keep in mind your mol ratios of reagents and how much starting material you are using.

Melting Point Range / Boiling point calculations etc.

Calculations for any of the numbers that you acquired in your procedure that need a correction or

averaging.

Your mp or bp should be a range, not a single number. In the case of a mp, you should always do two

(the more the better, but you probably have better things to do than take mp ranges all day) trials and

average out the initial and final melting points in your trials to come up with an average range. Just

recording a single number is plain lazy.

i.e: ((starting to melt1 + starting to melt2)/2) – ((finished melting1 + finished melting2)/2) = average range

Theoretical Yield

Here is where you calculate the theoretical yield of your product using the ACTUAL AMOUNTS used in

your lab. This must be recalculated and the number from your prelab will NOT work here.

Percent Yield

1

Using the theoretical yield and your yield, calculate the percent yield of your compound. Really, these are

easy marks if you take a few minutes to do it properly.

Spectral Tables

The spectral tables are used to conveniently tabulate your spectral results and make a quick comparison

of the literature spectra of your product with that obtained experimentally in the laboratory.

In the IR, it’s not critical to include every signal in your spectrum, but the ones that helped you to identify

the key functional groups in your product.

With the NMR, the best way to tabulate the signals for your compounds is to label the different protons

around your molecule Ha, Hb, Hc etc. See the NMR table in the DEET synthesis below. Once you do this,

you can simply refer to the signal for Ha, Hb etc in your discussion. Sounds so much easier than writing

out “the ortho aromatic protons” or “methyl next to CH” right?

These tables should be created within the document. It’s also best for clarity that you don’t let a table run

over a page. Start it on a new page if this happens. If you hover your cursor over the lines in the table,

you can resize the columns and rows. It’s best to make sure your words fit the boxes. Don’t make

columns wider than they need to be. Don’t make columns smaller than they need to be.

IR data. Table captions go above tables. Figure captions go below figures.

Chemical Structure / NameWavenumber (cm-1)

IntensityFunctional Group/

Bonding TypeExperimental Literature

Starting Material #1 -

#

#

#

Starting Material #2 -

#

#

#

Product

#

#

#

#

#

#

2

NMR

Chemical Structure /

Name / AssignmentAssignment

Chemical Shift (ppm)Integration Multiplicity Fragment

Experimental Literature

Starting Material #1

#1.A

#1.B

…

-

Starting Material #2

#2.A

#2.B

…

-

Product

P.A

P.B

…

Discussion

Ok, the discussion is where you get to show your understanding of what you did in the

lab in terms of the chemistry and whether you successfully completed a reaction or not.

There are three main parts to a 203/204 discussion, so let’s talk about them one at a

time.

1. The reaction you did and the mechanism. The WHY of the chemistry.Here is where you explain your experiment in terms of mechanisms and point out the interesting

observations made. Drawing out the mechanism helps for clarity and ease and must be done. With

the mechanism, there should be a paragraph explaining the major points to it, such as why the

mechanism is SN1 versus SN2, E1 versus E2, or any other mechanism type you will learn in class

(Markovnikov, electrophilic aromatic addition…). Here should be the place to talk about unusual

reagents (i.e., doing the reaction in acidic or basic conditions, or in an acid or base entirely) and why

the reaction needed to be done in this manner (usually you use an organic solvent that can be easily

removed for reactions).

3

2. Analysis of the spectra. The HOW you determined if your experiment was

successful.There are two types of experiment types in 203/204 which require slightly different discussions of IR

and NMR signals.

First, is the identification of an unknown molecule. In this type of experiment, you need to discuss all

the IR and NMR signals that lead you to conclude the structure of your molecule. This type of

discussion requires EXPLAINING WHY YOU THINK A PARTICULAR SIGNAL RELATES TO A

PARTICULAR PROTON OR FUNCTIONAL GROUP IN YOUR UNKNOWN MOLECULE.

The second is the synthesis of a product from a starting material. For this experiment type, the

discussion of the spectra does not require intricate explanation of what each signal means, you did

that in your NMR/IR tables through comparison to lit. spectra. What you should discuss ARE THE

CHANGES IN THE SPECTRA FROM STARTING MATERIAL TO PRODUCT THAT HELP YOU TO

CONCLUDE THAT YOUR REACTION WAS A SUCCESS OR NOT. E.g. an SN1 displacement of

propyl bromide to propanol with water involves the change of a bromide to a hydroxyl. So, go looking

for the IR and NMR signals that show that change.

3. Analysis of purity and yield. The How pure was your product and how well did

you make it.This section of the discussion, you should discuss the comparison of your experimental spectra and

mp/bp with literature data for the product/unknown compound. If the spectral data match (NMR shifts

and IR wavenumbers may be around 0.1-0.3 ppm different from exp to lit) and mp/bp are the same

(give or take a few degrees), you can confidently conclude that your product is pure.

In terms of the yield, you should discuss whether this yield is good or bad in terms of the experiment.

Things to consider here is if your yield is low, was the reason for the low yield due to the experiment

(side reactions etc), or perhaps losses in yield along the way (transfers, incomplete precipitation in

recrystallisation etc). If it’s above 100%, what do you think this means?

Other general stuff about the discussion.

When numbering the molecules in the discussion, they must conform to the numbers in a diagram or

figure. These numbers are always in bold font in both the figure and in the text and only appear after the

name of the molecule is used (see sample discussion for example.) The numbering is always sequential

and a molecule, once numbered must always use the same number.

4

If there are problems with your experimental results, this is where you would talk about it as well.

Make sure to talk about yield, purity of your compound, and any other major observations as well (i.e. BP,

gasses evolving, colour changes…) and make sure that they are incorporated into the proper sections of

the discussions.

YOUR DISCUSSION MUST BE DOUBLE SPACED, use proper grammar, paragraphs and be in the past-

passive tense. Size 12 font, Times or Arial. Your discussion must flow properly like a good story.

Imagine reading 40 of these labs.

You should be looking for a clear and concise discussion, it doesn’t need to be a tome. If you have

written more than 5-6 paragraphs in your discussion, you have probably said more than you need to. You

have 6 reports in 203 and 8 in 204, so this is definitely an area we TA’s will look for and help you in

improving as the year progresses.

Conclusion

Here are the major findings of your experiment. There should be NO NEW INFORMATION in this section

and it should be at most three sentences long. A good rule of thumb is stating the starting materials, the

mechanism used and the product that was made. Also include the yield, percent yield and the melting

point of the product. This section must also be written in full sentences with proper grammar.

Summary Box

The summary box should be in table format. The marker should be able to look at the box and get the

major information at a glance. The information needed here includes, but NOT LIMITED to structure,

name, yield, % yield, mp range, etc. In the case of an unknown starting material, include information that

would be needed in the reagent table for your prelab (i.e. hazards, density, MW, …). Do not include

spectral information here.

References

The references must be in ACS (https://pubs.acs.org/doi/pdf/10.1021/bk-2006-STYG.ch014) style and be

numbered as they appear in the report. You can use the same reference number several times for same

5

topic. Note for SDBS and other online resources, the link that is provided should not direct to the

homepage of the website, but the data that you are referencing, look for the URL that will give a direct link

to the page (in the case of SDBS, look on the left side in the window and a URL link is shown).

Attached spectra appendices

In this section, you should include a copy of EVERY SPECTRUM YOU USED IN YOUR REPORT. This

includes experimental NMR and/or IR spectra, along with the literature spectra you used as references in

your spectral tables/discussion. You should also annotate these spectra with labels to show your

assignments of the different signals in them.

Chemistry is all about providing evidence for your work. This section is included in the report to show the

evidence that you have actually obtained the appropriate spectral data for your report. Without it, how do

you prove that you actually did the experiment?

Page Numbers

PUT IN PAGE NUMBERS. Click on insert (Microsoft word), page number, and place on right side of footer (bottom right side of page).

6

Some other useful comments/pieces of advice to help your report and maximise your 203/204 learning experience.

In both the lab and your report, you are allowed and encouraged to stop and think about

what you are doing. You have enough time to get everything done and rushing can lead

to accidents. And hey, thinking might just help you to understand what is going on.

Your NMRs are going to be run in a solvent, so you are always going to see a solvent

signal in your spectrum. This is not an impurity, it is an artifact of using the solvent to

make the sample. Get to know the ppm of the different solvents signals so you don’t

confuse them with compound signals. Additionally, you will often see a water or reaction

solvent signal in your NMR sample. This is generally because you have to run the NMR

before your product is completely dry. So expect to see them, they shouldn’t necessarily

be considered impurities, go to your mp/bp to confirm the purity of your product.

When it comes to comparing literature and experimental NMR/IR spectra and mp/bp,

don’t expect them to be exactly the same. There is always going to be some slight

variation, be it either experimental or random error. It could be the calibration of the

instrument, variations in pressure or just random error among the slight variations. So

an exp mp/bp that is ±5% of the lit can be concluded as close enough.

Organic chemistry, particularly the synthesis side of things, usually does not need to be

precise in terms of mass and volume measurements. For example, if you are to add 10

mL of solvent to a reaction, then you don’t have to add 10.0 mL, if you have 9 or 11 mL,

it will work just fine.

Come to the lab prepared and ready to go. The better your preparation, the more you

will understand as you are doing the experiment, the more enjoyable it will be and the

more you will learn.

7

PROOF READ YOUR WORK. Read your report (especially the discussion) back to

yourself before you submit it. Does it make sense and say what you want it to say? If

not, revise it. There are many a lost mark here or there that can easily be rectified by a

quick read over your work.

8

Post Laboratory Report #6: DEET SynthesisRiley the Best Student

L69

January 1, 420 A.D.

Riley, Super TA

Results

Theoretical Yield

Volumes and masses of materials used

Mass of m-toluic acid: 0.43 g

Volume thionyl chloride (SOCl2): 0.55 mL

Volume dietylamine (DEA): 1.2 mL

Limiting reagent:

0.55mL SOCl2×1.63g /mL118.97 g /mol

=7.54×10−3mol

1.2mLDEA× 0.707 g /mL73.14 g /mol

=1.16×10−2mol

0.43 gacid136.15g /mol

=3.16×10−3mol

m-toluic acid is limiting

Theoretical Yield:

3.16×10−3mol DEET ×191.27 g/mol=0.60 gDEET

9

Percent Yield

Mass DEET product: 0.43 g

0.43g0.60g

×100%=72%

Spectral TablesTable 1: Infra-red data

Chemical Structure / NameWavenumber (cm-1)

IntensityFunctional Group/

Bonding TypeExperimental Literature1

m-toluic acid

-

3100-2600

2986

3000

1691

Broad

medium

Medium

Medium

Strong

-C(O)OH

sp2C-H

sp3C-H

-C=O of acid

Diethyl amine

-

3281

2968

Medium

Strong

Primary N-H

sp3C-H

#

#

#

3050

2935

1633

Medium

Strong

strong

sp2C-H

sp3C-H

-C=O of amide

10

N,N-diethyl-m-toluamide

Table 2: Nuclear Magnetic Resonance Data

Chemical Structure /

Name / AssignmentAssignment

Chemical Shift (ppm)Integration Multiplicity Fragment

Experimental Literature

m-toluic acid

A

B

C

D

E

F

-

12.45

7.94

7.92

7.40

7.32

2.41

1

1

1

1

1

1

br.s

m

m

m

m

s

COOH

Ar-H

Ar-H

Ar-H

Ar-H

Ar-CH3

A

B

C

-

2.7

1.1

0.9

4

6

1

q

t

s

CH2-CH3

CH2-CH3

N-H

N,N-diethyl-m-

toluamide

A

B

C

D

#

#

#

#

7.18

3.40

2.36

1.17

4

4

3

6

m

br.s

s

t

Ar-H

CH2-CH3

Ar-CH3

CH2-CH3

Discussion

The formation of the yellow oil, N,N-diethyl-m-toluamide (DEET), is a nucleophilic

substitution reaction on the carbonyl of the carboxylic acid group of m-toluic acid with

the secondary amine diethylamine. The reaction mechanism proceeds in several steps

via the very reactive intermediate 3-methylbenzoyl chloride, using catalytic pyridine.

11

Figure 1: Mechanism for the formation of DEET

The pyridine was used to initially deprotonate the toluic acid to the carboxylate anion

which can react with the thionyl chloride in the mechanism pathway of Figure 1 to make

3-methylbenzoyl chloride (2), releasing sulphur dioxide and hydrochloric acid by

deprotonating the pyridine, thus regenerating the catalyst. The amine is now able to

react with the newly formed acid, be deprotonated by the released chloride and finally

make the desired molecule DEET (3).

(Note: If there were any differences between your experimental product and literature

product, this is where you would mention the discrepancy and what it may be from.)

The NMR spectra of the starting materials and the product shows the molecule was

made. The initial m-toluic acid1 and diethyl amine (DEA)2 have distinctive signals in

their NMR. The carboxylic acid proton at 12.45 ppm from the acid spectra and the

amine proton at 0.9 ppm was lost in the product NMR.3

The NMR spectrum of 3 also has two interesting features. The spectrum shows the

aromatic hydrogens were more shielded than the toluic acid protons, most likely due to

the fact that the carboxylic acid group is more electron withdrawing than the amide

group. The second is that the two ethyl groups do not show as a nice quartet and

triplet, but are broadened. The broadening is due to the restricted rotation about the

nitrogen-carbon bond of the amide, making the two ethyl groups inequivalent.

12

The IR spectra also confirmed the formation of the product. The loss of the carboxylic

acid stretch of the toluic acid spectra1 and the secondary amine stretch of the DEA

spectrum4 in the spectrum of 3.3 What shows the formation of the amide group is the

change in position of the carbonyl stretch form 1691 cm-1 to 1633 cm-1. This change is

indicative of a smaller double bond character between the carbon and oxygen of the

amide than the carboxylic acid, further evidence of a restricted rotation about the carbon

nitrogen bond.

The yield of 0.43 grams (72%) of 3 was excellent, with no difference between the

experimental and literature spectra of both the IR and NMR, the product can be

considered pure. The loss may be due to incomplete conversion of the starting toluic

acid to the acid chloride, caused by stopping the reaction too soon and adding the

amine to the reaction.

Conclusion

By nucleophilic substitution chemistry, m-toluic acid was converted to N,N-diethyl-m-

toluamide using thionyl chloride and diethylamine. The yield of a yellow oil DEET was

excellent at 0.43g (72%). Through comparison of experimental and lit. 1H NMR spectra,

the DEET was deemed to be pure.

Summary Box

Structure / Name Yield %Yield

N,N-diethyl-m-toluamide

0.43 g 72%

References

13

(1) m-toluic acid; SDBS [online]; National Institute of Advanced Industrial Science and

Technology (AIST).

http://sdbs.db.aist.go.jp/sdbs/cgi-bin/direct_frame_disp.cgi?sdbsno=1000 (accessed

January 7, 2014).

(2) Diethylamine; [online]; Sigma-Aldrich: Oakville, ON.

http://www.sigmaaldrich.com/spectra/fnmr/FNMR000263.PDF (accessed January 8,

2014).

(3) N,N-diethyl-m-toluamide; SDBS [online]; National Institute of Advanced Industrial

Science and Technology (AIST).

http://sdbs.db.aist.go.jp/sdbs/cgi-bin/direct_frame_disp.cgi?sdbsno=7116 (accessed

January 7, 2014).

(4) Diethylamine; SDBS [online]; National Institute of Advanced Industrial Science and

Technology (AIST). http://sdbs.db.aist.go.jp/sdbs/cgi-bin/direct_frame_disp.cgi?

sdbsno=513 (accessed January 8, 2014).

(5) CRC Handbook of Chemistry and Physics, 73rd ed.; Lide, D.R. Ed.; Chemical Rubber

Company, Boca Raton, 1992, pp 9-151 – 9-153.

Spectra (note, two more spectra would be added, the experimental NMR

and IR)

Spectrum 1: m-toluic acid: 89.56 MHz in CDCl3 and referenced to CDCl3

14

Spectrum 2: Diethylamine (DEA): 300 MHz in CDCl3 and referenced to CDCl3

15

Spectrum 3: N,N-diethyl-m-toluamide (DEET): 89.56 MHz in CDCl3 and referenced to

CDCl3

Spectrum 4: m-toluic acid, infra-red spectrum: KBr disc

16

Spectrum 5: Diethylamine (DEA), infra-red spectrum, liquid film

Spectrum 6: N,N-diethyl-m-toluamide (DEET), infra-red spectrum: liquid film

17