Steam distillation

isky · Tue Apr 26, 2005 10:12 pm

Hi there, i'm glad to be here!

i'm tring to learn how steam distillation works and this is my first chemistry experience.

I was reading instructions about how to setup the glassware to make
it happend, but there are not images, just words about what to buy and how to connect the parts. Also, reading English is not easy for me...

So, after several days of web surfing i found this forum and a few
web stores where you can buy the glassware, after coping some images from those stores, i made a picture of what i think the setup should looks like.

Please, understand that this is the first time i see chemistry glassware and read about how to connect it...

You can find what i'm tring to do here:

designer-drugs.com/pte/12.162.180.114/dcd/chemistry/----.rp.html

There are a somethings that i don't understand:

1) In the instructions, the author says that you must use a two
liter, 2 neck round flat bottom flask, but i can't find flasks like
that, 2 neck flask are all round botton (at least in the web stores
that i found), that's why i used a round botton flask in the example,
also, i don't understand why a 2 neck flask is needed, cause he never
talk about using the second neck. Of course, may be he talks about it
but i just lost it...

2) About the steam distillation sloping splashhead, he says that you
may also use a sloping splashhead, i found one, and for what i saw,
the only difference is that the distillation one have a long tube
attached, and the other not, it's just the "head"

My problem is: If you use a simple sloping splashhead, where you
connect the hose? Cause there is not a "steam inlet" at least no in
the image that i saw.

I was thinking...If you use a "simple splashhead", you must connect
the hose to the second neck of the flask, and that
why he says a 2 neck flask is needed...Can that be right?

3) "Attach end of hose to release valve of pressure cooker that is
full of water", well i could not find any pressure
cooker in any of the web stores that i found. So, what is a pressure
cooker? How it works?

4) "Attach conderser to end of splashhead" In the image that i made
it's connected the way i think, by logic, should be
right. If it's wrong, please how to conecct it? And if it's right,
what to do whit the other two small inlets or outlets that the
conderser have?

Well, it's all for now, thanks a lot for reading this, and much much
thanks for helping out.

Cheers,
isky.

icecool · Insistent Chemist

I don't know that much about steam distillation,
but from what I've heard you don't need that splash thing.
And neither you need a steam inlet.
You can also use water with your product like sassafras bark.
And heat the water so the steam will evolve and so evaporate and condense threw your condenser and the oil (sassafras oil) with water will come over.
You can also do this with other stuff.
But this was the most likely example I could think off...
The condenser will have a slight slope stand, and not horizontal.
And the other 2 inlets are one for water in and one for water out.
Always connect the water like this, so the water will flow against the stream of distillate...
So from down to up...

Pressure cooker is just a pan with water which you heat and steam will evolve there is a outlet where you can attach a tube which leads to your setup.

And I think you don't need 2 necks.
It is preferable for other reactions you might need it once, it is more expensive to buy a 2 neck insted of a 1 neck though.

IndoleAmine · Dreamreader Deluxe

For steaming large amounts, additional sources of steam may be employed, but for simple operations it often is OK to directly heat the flask filled with water and substance to be steamed. The evolving steam will carry over some substance into the condenser, where both condense, separate and can be collected.

You can use a simple distillation setup with good condenser for steam distillation, just add some more H2O from time to time, to compensate for losses in volume.

And apply as much heat as you can!

isky · Tue Apr 26, 2005 11:54 pm

Thanks for reply Smile

for some reason the link i posted does not work, may be it's better if you know what exactly i want to learn. I say this cause the author says that "You will need these things, and no substitutions are allowed"

Try this link:

http://chemistry-images.freeservers.com/index.html

About the conderser, icecool says that the other 2 inlets are for water in and water
out. My questions are:

1) If i attach the conderser on top of the flask, i also need to attach a hose in the water-in inlet and a hose to the water-out inlet?

2) From where comes that water and where goes that water (the water in-out inlets)?

3) If i don't connect those water inlets, the conderser will not work right?

4) To catch the substance, i must put the jar under the end of conderser and not under the water inlets right?

5) Why this guy says that splash thing is needed? i mean, how that thing works? for what?

Sorry for asking that kind of questions, but i don't know nothing about chemistry...i'm tring to learn Smile

Cheers,

isky.

icecool · Insistent Chemist

1) If i attach the conderser on top of the flask, i also need to attach a hose in the water-in inlet and a hose to the water-out inlet?
Yes you do need to attach the water, and now the water will have to float from bottom to up, else there will be a waterfall which will not fill the full condenser with cold water.

2) From where comes that water and where goes that water (the water in-out inlets)?
Down to up, see question 1 explanation.

3) If i don't connect those water inlets, the conderser will not work right?
It will work, but less efficient, not everything will condense and thus go up in the air as a gas insted of as a liquid

4) To catch the substance, i must put the jar under the end of conderser and not under the water inlets right?
Yes you put the jar under the condenser (couldn't you think of this yourself?)

5) Why this guy says that splash thing is needed? i mean, how that thing works? for what?
If you are going to steam distill some oil or so then the oil can bump heavily or other liquids can bump so hard they fly directly into your receiver flask threw your condenser that is why this splash thing is for.

Now a question from me to anyone.
When steam distilling an Al sludge with alcohol you should basify it after all the alcohol is gone.
Well after almost all the alcohol is gone but the temperature hasn't risen yet.
There is a hard thick paste/cake of Al sludge inside the RBF.
SWIM SHOULD have added water but he added KOH solution.
So the Al would dissolve most likely now already together with the alcohol amine is already coming over right?
Since it isn't a lot of solvent it isn't that bad to waste this now SWIM will just have to extract the amine out of the water+solvent right?

isky · Wed Apr 27, 2005 3:33 am

Thanks icecool, what i wanted to ask in quetions 2 and 3 was:

2) The source from where that water comes, it's not the flask right? as the neck of the flask is already attached to the "main in" of the conderser, so you need to add another source like a water tap? Put a hose and attach it to the water in inlet, then the water will go from bottom to top, where is that water throw away after it comes out of the water out inlet?

3) That water that comes out of the water out inlet is NOT the sustance right? so a must put the jar at the end of the conderser and not at the end of the water out inlet right?

So, the splash thing is almost the same that a conderser, may be it better to do it like you say, just a conderser...

Cheers
isky

icecool · Insistent Chemist

The water outlet is on the condenser.
Not on the end of the condenser.
A condenser has a double walled glass tube.
So the water will float around the tube and threw the tube your product is going( the substance).

stratosphere · Sun May 22, 2005 2:39 pm

im a little confused about the theory of steam distillation. if your extracting a substance thats boiling point is well above that of water , like safrole for instance, then why does it come over with the steam?

also is there any rule of thumb as to how much water it wil take to extract X grams of substance?

IndoleAmine · Dreamreader Deluxe

Some high-boiling substances form azeotropes with water, meaning they have a stable mixture with a constant boiling point and defined composition, and these azeotropes behave like own substances when distilling...

EtOH + H2O is the most well-known azeotrope, it boils at 79.3°C and contains 96% ethanol and 4% H2O.

Therefore you can't get 100% EtOH from distillation, for example.

Another good example is benzaldehyde, it forms an azeotrope with water, containing 10-11% (from memory Smile

) of aldehyde and boiling at 96-97°C IIRC....
(but don't quote me on that)

Each azeotrope has its own composition, usually cosisting of more water and less substance, if substance X is higher boiling than water..

i_a

stratosphere · Mon May 23, 2005 5:07 pm

ahh, that clears it up a bit, now i know what the azeotrope tables ive seen in the crc handbook are good for.

Sektor · Wed May 25, 2005 10:13 am

when exactly does swim apply the steam distillation to the M*** FB? is it after the HI+RP reduction of pfed solution has been done/dilutted with equal DH20 and then NP washed? what does this accomplish?, what steps does it compensate for otherwise? (i:e A/B extract?)
many thanks

loki · guinea pig

i'm pretty sure a plain old distillation rig is perfectly good for steam dist, stainless or glass is ok, i don't think copper such a good idea. you can run the steam inlet in where the thermometer would have gone, glass rod is prolly easiest to get this right, i suppose a stanless steel tube would be more durable, one hole cork and hose attachment on an earlenmeyer with water as a steam source, or if u got a pressure cooker, attach to the vent.

it is my understanding that ---- actually steam distills without using steam hose gear, and doing it this way has the advantage of significantly separating from the ephedrine which does require the hotter steam to make it work. (it's not a 100% separation but more like 90% or so) so if the intended material is post reaction product, that's the way to do it. Should be able to just run it immediately after rxn, just dilute rxn mixture, filter, then basify strongly (pH 13ish) and distill it. I spose a defat on the rxn solution wouldn't hurt tho, sometimes the rxn lets sum of the gaks out of the rp and stuff, don't want to distill them across or make them polymerise and wrap the product in its polymer tentacles in strong hot base solution - neutralise the rxn fluid until it loses the red colour taint before doing that, red is from excess I2 usually.

hAzzBEEn · Wed May 25, 2005 10:38 pm

kwmi · Wed Jun 01, 2005 9:31 am

SWIM wants some sassafras oil but is afraid that the direct purchase of such a product may draw some unwanted attention . SWIM thinks to steam distil ssassafras root bark to obtain his oil and stay out of trouble. SWIM does not want to buy anymore glassware and was glad to hear IndoleAmine say that a simple distillation setup could effectively be used for steam distillations. Swim will talk a little because he has a good understanding of chemistry, but I hope anybody corrects SWIM if he is wrong.

Sassfras rootbark is dried and pulverized into a dust and added into a 2L 2-neck roundbottom flask. Water is added so that the total volume does not excede 666mL (SWIM thinks RBF should never be filled more than 1/3 of capacity). Ice water is pumped through the condensor and the roundbottom flask is placed in an oil bath and refluxed until the water begins distilling.

Now, Does the steam form an azeotrope with the oils from the bark that distills at or around the temperature that the steam is distilling at (not 100 C b/c vacuum may be used)?

The oil and water would not be miscible in the liquid state and the contents of hte collection flask can be placed in a sep funnel to isolate the oil.

Is this a legimate way to get sassafras oil? How many ml of oil will distill over 500 mL of dH2O? It seems like it may be time consuming and tedious.

loki · guinea pig

i'm not exactly sure how much distills but from seeing mint steam distilled in highschool chem i'd say it's probably 5-10% comes over as oil.

i believe that it is preferable not to fill a distillation flask over half way, but it is more about whether you might get superheating and bumps and choking or flooding the distillation rig, which is probably not so relevant with steam distillation.

i'm not absolutely certain sassy oil steam distills but it's quite possible that it does.