<< Chapter < Page Chapter >> Page >

Part 1:

Preparation of 1-methylbutyl magnesium bromide:

1. Prepare a 5.0 mL conical vial containing a magnetic spin vane and equipped with a condenser. Weigh and place 75 mg (approximately 3-4 pellets) of magnesium in the vial, and then add a small crystal of iodine (Do not add excess iodine), followed by 500 µL of anhydrous ether.

NOTE: Metal magnesium you will be provided with has a coil shape and has been cut into small pieces. This material should be handled with forceps only. Four to five small pieces of Mg weigh about 75 mg.

NOTE: Plastic syringes tend to get stuck when filled with ethyl ether. Be ready to push a bit harder on a syringe plunger when adding liquid to the reaction mixture.

2. Prepare a solution of 520 µL of 2-bromopentane in 600 µL of anhydrous diethyl ether in a dry 5 mL conical vial. Use a syringe to deliver each solution. TA will do that.

3. After the assembly has cooled to room temperature, then draw the 2-bromopentane solution into a 1.0-mL syringe and then insert the syringe needle through the rubber septum on the top of the condenser. (Do not heat the closed system, it may explode!!!!)

4. While stirring the heterogeneous mixture, slowly add 6-8 drops of the 2-bromopentane ether solution to initiate the formation of the Grignard reagent. The evolution of tiny bubbles from the surface of the magnesium is evidence of a reaction.

 

5. When the reaction has started, slowly add the remainder of the 2-bromopentane-ether solution drop wise over a 3 to 5-min period. Warm the reactants slightly. Upon completion of this addition, draw the rinse in the capped vial into the syringe and add it through the septum in a single portion to the reaction vial. Stir the resulting solution for 15 min.

Caution

Do not overheat. Overheating will cause loss of ether solvent. (The b.p. of ether is 34.6 °C.) Small fragments of magnesium may remain at the end of the addition of the alkyl halide.

6. Cool the gray-colored solution of Grignard reagent to room temperature.

Preparation of propanal (propionaldehyde)

1. Prepare a solution of the aldehyde by weighing 100 µL of propanal into a tared, oven-dried, 3 mL conical vial followed by the addition of 200 µL of anhydrous diethyl ether. Cap the vial after solution is ready. The propanal is the limiting reagent and therefore an accurate weight should be recorded for the yield calculations. TA

Part 2: grignard reaction

1. Now add the propanal solution carefully, with stirring, to the Grignard reagent over a period of about 30 sec at such a rate as to keep the ether solvent at a steady reflux.

2. Rinse the vial that contained the propanal solution with 100 µL of anhydrous diethyl ether and add to the Grignard reagent. This step insures that all the propanal is added to the Grignard reagent.

3. Stir the reaction mixture for 5 min and then allow it to cool to room temperature. Remove the conical vial and take off the cap. It is recommended that the vial be placed in a beaker to prevent tipping and loss of product.

Part 3: isolation of product

1. Hydrolyze the magnesium alkoxide salt by addition of 2.0 mL of water. Stir the resulting mixture for 5 min. A two-phase (ether-water) reaction mixture develops as the magnesium salt is hydrolyzed. Remove any unreacted magnesium.

Questions & Answers

how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
Maciej
Do somebody tell me a best nano engineering book for beginners?
s. Reply
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
s.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
SUYASH Reply
for screen printed electrodes ?
SUYASH
What is lattice structure?
s. Reply
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
China
Cied
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
AMJAD
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
AMJAD
what is system testing
AMJAD
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
Hello
Uday
I'm interested in Nanotube
Uday
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
Prasenjit
can nanotechnology change the direction of the face of the world
Prasenjit Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
Privacy Information Security Software Version 1.1a
Good
Berger describes sociologists as concerned with
Mueller Reply
Got questions? Join the online conversation and get instant answers!
QuizOver.com Reply

Get the best Algebra and trigonometry course in your pocket!





Source:  OpenStax, Chem217labsfall07. OpenStax CNX. Oct 16, 2007 Download for free at http://cnx.org/content/col10463/1.4
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Chem217labsfall07' conversation and receive update notifications?

Ask