06-10-02 20:00
No 319475
I realize that this may seem simple to some. But I am a beginning chemist with safety in mind. I am purchasing glassware, and was planning on getting all flatbottom flasks. However I was told by someone the problem with the flatbottom flasks is the risk of them imploding when applying a strong vacuum. If that is the case would you use a heating mantle, or what would you reccommend. Thanks
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(Hive Bee)
06-10-02 20:31
No 319485
Roundbottoms only if you are going to vacuum.Mantle or oilbath depending on the procedure you're doing.
(rated as:eggsellent)
(Hive Bee)
06-10-02 20:35
No 319487
if it's a really good oil vacuum pump, then yes, the fbf will implode and imbed glass in your face if you're close enough (watching the reaction in amazement), otherwise, if it's just an aspirator, SWIM's found that fbf's are okay (depending on the wall thickness).
Why?
(Stranger)
06-10-02 21:02
No 319496
As I said, I am a beginning chemist, and am learning from a variety of sources. Suppose I decide to use an oil less diaphragm pump that pulls about 29" of Hg. Will the flat bottom work. I would love to be able to use a magnetic stirrer/ hot plate in one. Thanks for the reply.
We need to be more nomadic. I nomad at you...you nomad at me.
(Stranger)
06-10-02 21:29
No 319506
the answers to your questions can be found in the thread entitled "flat versus round bottom flasks" in the aquisition forum (starting with Post 89079 (bliss: "flat versus round bottom flasks", Chemicals & Equipment)). Sorry I can't link the post in - i cannot use javascript with my browsing arrangement and don't know the commands to link posts in manually.
have a look at the posts in the above thread by Osmium - he shows why a FBF should not be used even with aspirator vacuum.
./
(Stranger)
06-11-02 00:10
No 319546
Thanks so much for telling me about the round bottom versus flat bottom flasks. It has answered my question, helped me to ensure that I create as safe an environment as possible. Thanks again.
We need to be more nomadic. I nomad at you...you nomad at me.
(Hive Bee)
06-11-02 02:01
No 319581
Flat bottom flasks are great for some reactions, just not for vacuum distillation. Swim distills dcm all the time in a flat bottom flask, but then he does it with no vacuum because the boiling point of DCM is so low. Get a distillation kit from a glassware supplier with a 1L round bottom flask and a 500ml round bottom flask. The 1L flask will fit comfortably in a 1.5Qt stainless steel bowl (clamped in of course, not actually touching the bowl), and adding about 20fl. oz. of peanut oil will submerge the flask about 3/4 of the way. Put this on your hot plate/stirrer and you've got an excellent compact oil bath which is perfect for distilling whatever you need. Don't forget to get an egg-shaped stir bar!
A watched pot will indeed boil.
(Stranger)
06-11-02 07:27
No 319706
I have actually decided on the contrary, and I am going to just go with the round bottom, and heating mantle, because I plan on doing a bunch of vacuum distillation. Now my question is how do you get the stirring mechanism into the picture since they aren't built in with the mantle? Or am I just not knowledgeable enough yet to understand that I don't even need to worry about that. Thanks for your time.
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(Old P2P Cook)
06-11-02 07:45
No 319713
You use the magnetic stirrer functionality of a stirrer/hot plate. You place the soft shell heating mantle on the stirrer/hot plate and stir through the shell.
(Hive Bee)
06-11-02 11:41
No 319781
They also make stirrers without hot plates that are alot cheaper. But if you buy the stirrer\hot plate when your mantle quits youll have the hot plate as a backup.
I think i like it!
(Hive Bee)
06-11-02 17:13
No 319831
Nomad -
You need to do a lot more reading. Do you have the Zubrick book? Read what he says and look at the pictures. I think the reason you want to go with FBF is because you want to be able to let the flask sit on the hotplate/mantle, and you have no idea about stands, clamps, oil baths, etc.
Here's the best advice you'll ever get. Wait. Read. Save money and buy the proper equipment: Hotplate/stirrer combo, Round bottom flasks, vacuum pump (a good one, and not an aspirator).
It's ok for chemists to use doityourself equipment, because they know what they are doing. For self taught bees like us, having the best equipment means less screwups and no second guessing. Believe me, that's important.
"No...why would I need a fire extinguisher?"
(Stranger)
06-11-02 19:46
No 319864
I am in the process of doing more research, and am learning more each day. I will check out the Zubrick book. Thanks
We need to be more nomadic. I nomad at you...you nomad at me.
(Hive Bee)
06-12-02 03:09
No 319992
Without reading the Zubrick...
some of the stuff attempted here can kill you and at the least cause a REALLY BIG fire...
read the Zubrik..swip2112 has had two implosions...
With an ASPIRATOR!
"If they make me dig up roots, I'm going postal.."
(Stranger)
06-13-02 02:59
No 320516
What's the boiling point of the peanut oil? I am realizing that the hot plate with oil bath is the way to go. Thanks
We need to be more nomadic. I nomad at you...you nomad at me.
(Stranger)
06-13-02 03:11
No 320521
Would you suggest any particular edition, or would you say that only the most recent would be the way to go?
We need to be more nomadic. I nomad at you...you nomad at me.
(Chief Bee)
06-13-02 05:27
No 320568
The editions are very similar, go for the cheapest one.
(Stranger)
06-14-02 07:26
No 321055
Exellent refs indeed starlight:
Post 89079 (bliss: "flat versus round bottom flasks", Chemicals & Equipment)
and for <$50 at :http://www.amazon.com/exec/obidos/ASIN/0
you get - The Organic Chemistry Lab Survival Manual: A Student Guide to Techniques <- recommended by everyone,
finally IMO, and near-nonexistant experiance @ Rb IS...that thet automatic sritting thing that gets to go on there - very very cool esp under refluxing
AND mantle + thermometer makes more icing on the cake that is legally allowed in some countriried
RB + (1-3 neck) w/ ,mantle, thermometer, varisc controller and condendsor sre probsably 5 pieses of glasswhere you'll never regret investing in
(shoppings SO much fun!- enjoy!)
I am jacks addiction - jack gets me drugs - I keep jack happy
(Stranger)
06-14-02 19:18
No 321286
Thanks, and in case anyone want's to know, there are some for sale if you do a search under google....used books. I found some for under $10.
We need to be more nomadic. I nomad at you...you nomad at me.