1. What would happen to the yield of the product if you used regular lab grade ether instead of anhydrous ether to dissolve the carbonyl compound in steps 2 and 3 above? Write a chemical equation illustrating the process. Use structural formulas or skeletal structures.

Organic Chemistry
9th Edition
ISBN:9781305080485
Author:John E. McMurry
Publisher:John E. McMurry
Chapter31: Synthetic Polymers
Section31.SE: Something Extra
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Need answer for question 1. My reagents were 1-Bromobutane and Acetone. 

olo
&
EXPERIMENT 3: GRIGNARD REACTION PROJECT
It is crucial that you work quickly in setting up your apparatus before it has time to
pick up moisture from the air!
theonk
2. Set up a dry 250-mL RB flask over a magnetic stirrer in the hood. Fit the RB flask with a
Claisen adapter, an addition funnel, a reflux condenser fitted with rubber tubing, and a Teflon
coated stir bar. Add 0.11 mol of magnesium turnings to the flask and cover it with a bit of
anhydrous diethyl ether. (We have two grades of ether in the lab: anhydrous and lab grade.
YOU MUST USE ANHYDROUS diethyl ether at this step.)
3. Measure out your calculated volume of 0.10 mol of your alkyl halide. Place 1 mL of this alkyl
halide directly in the flask with the Mg turnings/ether mixture and dissolve the rest of the alkyl
halide in 40 mL of anhydrous diethyl ether and place the liquid in the addition funnel and
connect it to the reaction flask. Turn the water on the condenser. (No floods please!)
4. The reaction should begin shortly. The formation of the Grignard reagent is exothermic and
causes the ether (BP 34.6 °C) to boil vigorously. You can tell that the reaction is going because
the ether will start to boil and bubbles will form around the active Mg turnings, and ether will
start to drip from the condenser. (If nothing happens after a few minutes, you may have to
break some of the magnesium turnings with a glass stirring rod to expose fresh metal to the
alkyl halide). Once the reaction starts you can add the alkyl halide solution dropwise over a 20-
minute period, at such a rate that the reaction keeps boiling, but not too rapidly!! In some
cases, if the Grignard reaction is slow to start, you may have to start the reaction in a test-tube
and then pour the boiling reaction mixture into the flask to get the magnesium turnings to start
reacting. See your instructor if you are having difficulty in starting the Grignard.
5. Once all of the alkyl halide has been added, stir the solution at room temperature until the ether
stops boiling.
Vacetone used = 2₂403 m/
Yether. Vdiethyl ether =
20ml
6. Now dissolve the calculated volume of 0.10 mol of the carbonyl compound you selected to use
in 20 mL of anhydrous ether and put the solution into the addition funnel you just used for
adding the alkyl chloride. (Do not wash the addition funnel.) Carefully add the carbonyl
compound solution to the Grignard reagent. This reaction is VERY exothermic. Have an ice
bath ready in case you have to cool the flask down when you add the carbonyl compound. If
you use an ice bath make sure that you are stirring the solution with the magnetic stirrer. After
all of the carbonyl compound has been added, bring the solution up to room temperature and
stir for several minutes. There may be a precipitate on the sides of the flask but don't worry.
Some magnesium salts are not very soluble in ether.
Wednes
Administ
7. Place the reaction flask in an ice bath. Prepare a dilute HCl solution by mixing 17 mL of 6.0 M
HCl with 30 mL of water. Carefully and slowly add this HC1 mixture to the reaction flask.
(You will need about 0.10 mol of HCl, but no more.) The purpose of the HCl is to help
dissolve the magnesium salts and unreacted magnesium turnings. (If you use too much HCl you
may cause the OH group of your product to be replaced by Cl! After all, some of you are
making 3° alcohols and you recall from CHEM 200 that 3° alcohols form halides very rapidly
with HX via an SN1 process.)
1468.37cm
bending
1364.380
157.03cn
125ml
8. Pour your mixture into a separatory funnel. Separate the aqueous layer from the ether layer.
Dry the ether layer with anhydrous MgSO4. This is a good stopping point.
Transcribed Image Text:olo & EXPERIMENT 3: GRIGNARD REACTION PROJECT It is crucial that you work quickly in setting up your apparatus before it has time to pick up moisture from the air! theonk 2. Set up a dry 250-mL RB flask over a magnetic stirrer in the hood. Fit the RB flask with a Claisen adapter, an addition funnel, a reflux condenser fitted with rubber tubing, and a Teflon coated stir bar. Add 0.11 mol of magnesium turnings to the flask and cover it with a bit of anhydrous diethyl ether. (We have two grades of ether in the lab: anhydrous and lab grade. YOU MUST USE ANHYDROUS diethyl ether at this step.) 3. Measure out your calculated volume of 0.10 mol of your alkyl halide. Place 1 mL of this alkyl halide directly in the flask with the Mg turnings/ether mixture and dissolve the rest of the alkyl halide in 40 mL of anhydrous diethyl ether and place the liquid in the addition funnel and connect it to the reaction flask. Turn the water on the condenser. (No floods please!) 4. The reaction should begin shortly. The formation of the Grignard reagent is exothermic and causes the ether (BP 34.6 °C) to boil vigorously. You can tell that the reaction is going because the ether will start to boil and bubbles will form around the active Mg turnings, and ether will start to drip from the condenser. (If nothing happens after a few minutes, you may have to break some of the magnesium turnings with a glass stirring rod to expose fresh metal to the alkyl halide). Once the reaction starts you can add the alkyl halide solution dropwise over a 20- minute period, at such a rate that the reaction keeps boiling, but not too rapidly!! In some cases, if the Grignard reaction is slow to start, you may have to start the reaction in a test-tube and then pour the boiling reaction mixture into the flask to get the magnesium turnings to start reacting. See your instructor if you are having difficulty in starting the Grignard. 5. Once all of the alkyl halide has been added, stir the solution at room temperature until the ether stops boiling. Vacetone used = 2₂403 m/ Yether. Vdiethyl ether = 20ml 6. Now dissolve the calculated volume of 0.10 mol of the carbonyl compound you selected to use in 20 mL of anhydrous ether and put the solution into the addition funnel you just used for adding the alkyl chloride. (Do not wash the addition funnel.) Carefully add the carbonyl compound solution to the Grignard reagent. This reaction is VERY exothermic. Have an ice bath ready in case you have to cool the flask down when you add the carbonyl compound. If you use an ice bath make sure that you are stirring the solution with the magnetic stirrer. After all of the carbonyl compound has been added, bring the solution up to room temperature and stir for several minutes. There may be a precipitate on the sides of the flask but don't worry. Some magnesium salts are not very soluble in ether. Wednes Administ 7. Place the reaction flask in an ice bath. Prepare a dilute HCl solution by mixing 17 mL of 6.0 M HCl with 30 mL of water. Carefully and slowly add this HC1 mixture to the reaction flask. (You will need about 0.10 mol of HCl, but no more.) The purpose of the HCl is to help dissolve the magnesium salts and unreacted magnesium turnings. (If you use too much HCl you may cause the OH group of your product to be replaced by Cl! After all, some of you are making 3° alcohols and you recall from CHEM 200 that 3° alcohols form halides very rapidly with HX via an SN1 process.) 1468.37cm bending 1364.380 157.03cn 125ml 8. Pour your mixture into a separatory funnel. Separate the aqueous layer from the ether layer. Dry the ether layer with anhydrous MgSO4. This is a good stopping point.
39
EXPERIMENT 3: GRIGNARD REACTION PROJECT
9. Distill off the ether (BP 34.6 °C) and depending upon the boiling point of the alcohol, distill
that too. You have to look up the boiling point of the alcohol so you know at what temperature
to collect the product. You will save everything that boils over 40 °C up to the boiling point of
the alcohol then switch receivers and collect the product. The product should be analyzed. The
ether should be placed in the waste ether jar in the hood.
10. Take the IR spectrum and refractive index of your product. You may also want to assess its
purity by injecting it into a gas chromatograph, using 205 DC-200 column with the column
temperature at 113°C. Make sur
that the GC oven temperature is above the BP of your
alcohol. Turn in your product in a labeled vial.
33
11. Write a detailed report about your experiment and determine the yield and % yield. Comment
on your IR results and other physical properties you have determined and compare them to the
de fermer
literature values for your compound.
-Ankerß vos resultats et autres prop.physiz.
Comparer les aux valeurs de la interature fr
Votre composé.
2
mag expe
mas
the ant
Post-Lab Questions:
1. What would happen to the yield of the product if you used regular lab grade ether instead of
anhydrous ether to dissolve the carbonyl compound in steps 2 and 3 above? Write a chemical
equation illustrating the process. Use structural formulas or skeletal structures.
2. What is the formula of the magnesium salt of the alcohol formed after the carbonyl compound
has been added to the Grignard reagent? Use structural formulas or skeletal structures.
3. In Step 7, what is the molarity of the dilute HCl solution you prepared? If you were to use the
entire solution, how many moles of HCI would you have added?
4. What is the purpose of adding the HCl solution in Step 7? Answer by writing an equation,
using structural formulas or skeletal formulas for each of the following:
a) the reaction of aqueous HCl with the magnesium salt in question 2.
b) the reaction of aqueous HC1 with the unreacted magnesium turnings.
5. If you added too much HCl and your Grignard product should undergo SN1 or SN2 reaction to
form the halide, what are the structure and physical properties of this side product? Do you
have any evidence that this side product may be present? Explain fully.
6. If the reaction had undergone elimination, what are the structure and physical properties of this
side product? Do you have any evidence that this side product may be present? Explain fully.
|-bromo-butane
2-methyl-2 hexanol
OH
39
Admin
Wednesday, Feblu
1.
WE
کم
C
и
Ca
Transcribed Image Text:39 EXPERIMENT 3: GRIGNARD REACTION PROJECT 9. Distill off the ether (BP 34.6 °C) and depending upon the boiling point of the alcohol, distill that too. You have to look up the boiling point of the alcohol so you know at what temperature to collect the product. You will save everything that boils over 40 °C up to the boiling point of the alcohol then switch receivers and collect the product. The product should be analyzed. The ether should be placed in the waste ether jar in the hood. 10. Take the IR spectrum and refractive index of your product. You may also want to assess its purity by injecting it into a gas chromatograph, using 205 DC-200 column with the column temperature at 113°C. Make sur that the GC oven temperature is above the BP of your alcohol. Turn in your product in a labeled vial. 33 11. Write a detailed report about your experiment and determine the yield and % yield. Comment on your IR results and other physical properties you have determined and compare them to the de fermer literature values for your compound. -Ankerß vos resultats et autres prop.physiz. Comparer les aux valeurs de la interature fr Votre composé. 2 mag expe mas the ant Post-Lab Questions: 1. What would happen to the yield of the product if you used regular lab grade ether instead of anhydrous ether to dissolve the carbonyl compound in steps 2 and 3 above? Write a chemical equation illustrating the process. Use structural formulas or skeletal structures. 2. What is the formula of the magnesium salt of the alcohol formed after the carbonyl compound has been added to the Grignard reagent? Use structural formulas or skeletal structures. 3. In Step 7, what is the molarity of the dilute HCl solution you prepared? If you were to use the entire solution, how many moles of HCI would you have added? 4. What is the purpose of adding the HCl solution in Step 7? Answer by writing an equation, using structural formulas or skeletal formulas for each of the following: a) the reaction of aqueous HCl with the magnesium salt in question 2. b) the reaction of aqueous HC1 with the unreacted magnesium turnings. 5. If you added too much HCl and your Grignard product should undergo SN1 or SN2 reaction to form the halide, what are the structure and physical properties of this side product? Do you have any evidence that this side product may be present? Explain fully. 6. If the reaction had undergone elimination, what are the structure and physical properties of this side product? Do you have any evidence that this side product may be present? Explain fully. |-bromo-butane 2-methyl-2 hexanol OH 39 Admin Wednesday, Feblu 1. WE کم C и Ca
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