megalomania
June 19th, 2003, 10:45 PM
John456
Frequent Poster
Posts: 105
From:
Registered: MAR 2001
posted 05-30-2001 05:28 PM
--------------------------------------------------------------------------------
Hey,
Decided to buy some jointed glassware anyway since i wont have to deal with stoppers and can use it for vacuum distillation. The stuff i bought has 24/40 joints and looks like this:
I am thinking of buying an oil vacuum pump so i can make high concentration nitric acid among other things, and have a few questions before i do. Number one, can i just hook the pump directly up to the vacuum adapter, or would i need something to prevent gas and liquid from going into the pump? Also, does anyone have a web page or can provide any info on which model pumps are suitable for distillation, pricing, etc? On a related note, would i need any sort of special clamps to hold the joints together and prevent leaks, or will grease work fine?
Thanks! -John
[This message has been edited by John456 (edited May 30, 2001).]
PYRO500
Moderator
Posts: 1465
From: somewhere in florida
Registered: SEP 2000
posted 05-30-2001 06:24 PM
--------------------------------------------------------------------------------
I would get a bubbler just to make sure the nitric acid reminant vapors dont ruin the pump
10fingers
Frequent Poster
Posts: 411
From: USA
Registered: SEP 2000
posted 05-30-2001 07:17 PM
--------------------------------------------------------------------------------
Did you get this from U.G.T? I have one that looks identical to it. You do need a trap to keep acid vapors from going into the pump.
I have a refrigeration type vacuum pump. There is a aspirator type pump that hooks up to your faucet. There about $10.00 at Pyrotek. With them you would not need any type of trap for vapors but I have never tried one so I do not know if they would supply enough vacuum for what you want to do.
I have been able to obtain a high vacuum without using any kind of joint grease.
John456
Frequent Poster
Posts: 105
From:
Registered: MAR 2001
posted 05-30-2001 07:37 PM
--------------------------------------------------------------------------------
Yes, it was from UGT Damn, how much does a trap run and where can i get one? I already have an aspirator and the vacuum is not even worth using. What would be the purpose of the bubbler Pyro? Recycling the vapors back into the liquid?
Edit: A trap is a sort of condensor cooled by liquid Nitrogen or solid CO2 right? If so i can probably make one, but i dont know if i want to risk it since vacuum pumps are quite expensive. Also, when people say "X Inches of Mercury" what does that measure? Would 23" of Hg be suitable for distillation?
[This message has been edited by John456 (edited May 30, 2001).]
PYRO500
Moderator
Posts: 1465
From: somewhere in florida
Registered: SEP 2000
posted 05-30-2001 09:11 PM
--------------------------------------------------------------------------------
b trap we mean somethign to keep the vapors away form the pump, It dosent have to use cold temps, That is a cold trap. what I was taloking about is something like this:
glassware ======|| ||===========vacuume pump tubes || || -^^^^^^^^- | ! ! | | ! | Water |--------| | ! o oo | | ! o o | ----------
the water absorbs harmful vapors from reaching the pump.
this U.G.T do they have a page on the web?
there I fixed it
[This message has been edited by PYRO500 (edited May 30, 2001).]
John456
Frequent Poster
Posts: 105
From:
Registered: MAR 2001
posted 05-30-2001 09:23 PM
--------------------------------------------------------------------------------
The picture kinda got messed up in the posting but i think i see what it was supposed to look like. Sort of like a bottle of water between the vacuum and the glassware , right? this seems like it could be easily made. UGT's page is www.unitedglasstech.com , but check out their auctions on ebay, they have the same stuff they are selling their for a lot less.
John456
Frequent Poster
Posts: 105
From:
Registered: MAR 2001
posted 05-30-2001 10:43 PM
--------------------------------------------------------------------------------
Ahh, i see. That can be easily made. My next question is: Will a vacuum pump that can pull 23" of mercury be good for distillation?
PYRO500
Moderator
Posts: 1465
From: somewhere in florida
Registered: SEP 2000
posted 05-30-2001 10:56 PM
--------------------------------------------------------------------------------
can you list the part numbers of the stuff you ordered? I am also looking into setting up a general purpose distillation rig for making nitric acid with amonnium nirtate and H2SO4. their prices at u.g.t are pretty good too.
10fingers
Frequent Poster
Posts: 411
From: USA
Registered: SEP 2000
posted 05-30-2001 11:31 PM
--------------------------------------------------------------------------------
I was having the same problems with acid vapors getting into my pump and ruining the oil. I tried a water trap but the water readily evaporates at low pressure and that gets into your oil. I am now using 2 in.x 8 in.piece of pvc pipe with hose fittings on each end. The pipe is filled with baking soda. There are several layers of filter paper in the pipe to prevent the baking soda from being sucked into the pump. I have only used this two times and it seems to be working. The soda would have to be replaced periodically.
The pump I have is a refrigeration type which I picked up at a pawn shop for $30.00, it is capable of pulling 30 in. of vacuum, but It seems the whole system works better at around 15 or 20 in. At high vacuum there is a tendency for the mixture to erupt and spill over into the condenser.
PYRO500
Moderator
Posts: 1465
From: somewhere in florida
Registered: SEP 2000
posted 05-30-2001 11:48 PM
--------------------------------------------------------------------------------
I was thinking of using one of those nitro fuel pumps (for use in nitrus oxide car systems) it can presurize fuel to 100 psi, I was thinking of using one in a water aspirator? do you think it would work?
nbk2000
Moderator
Posts: 1096
From: Guess
Registered: SEP 2000
posted 05-31-2001 12:44 AM
--------------------------------------------------------------------------------
You can't use a water trap in a high vacuum system because the water boils off at room temperature or less. It's been ages since I last dealt with such things so I don't know what you could use to catch the nitric vapors besides a cold trap.
But, I can tell you that grease and pure nitric equals bad! If the grease is silicon, than that should be OK. Wrap the joints with several layers of teflon tape to prevent acid vapors leaking out, and clips aren't needed if your support clamps are properly set up.
Since you'll be using vacuum, be sure all exposed glassware, especially the flasks, are checked for cracks and scratchs, and wrapped with tape and emplaced in a sturdy container that will contain the glass and acid in case of implosion, which is a common occurance during vacuum work.
PYRO500
Moderator
Posts: 1465
From: somewhere in florida
Registered: SEP 2000
posted 05-31-2001 01:16 AM
--------------------------------------------------------------------------------
what about a commercial vapor drying and netrulizing trap tube avalible from chromatagraphy supply companys
-A-
Frequent Poster
Posts: 100
From:
Registered: JAN 2001
posted 05-31-2001 01:50 AM
--------------------------------------------------------------------------------
John456, that's almost the same setup I am waiting for...no money yet, you are a lucky guy. A trap bottle is just that, generally a bottle filled with water, a stopper with two holes and a tube in each hole. I suggest that you put the trap bottle in a mix of ice and salt to keep the water cool and prevent boiling. A good vacuum pump costs a lot, too much for me. A water aspirator can be used instead. Make sure you are using thick tubing. Oh, and from the picture I can't see what's the volume of the flasks, but I advise against using anything bigger than 250ml as an implosion can occur.
c0deblue
Frequent Poster
Posts: 229
From:
Registered: JAN 2001
posted 05-31-2001 03:34 AM
--------------------------------------------------------------------------------
A quite respectable vacuum pump can be improvised from an old refrigerator compressor. Just be sure to get everything with it you need when removing it from the junked unit, and cut the tubing long enough so you'll have something to work with. These are pretty efficient, and most can draw down to almost 30" Hg - a LOT stronger than needed for HNO3 distillation.
Does anyone know whether teflon sleeves for rubber stoppers (or rubber-filled teflon stoppers) are available anywhere?
John456
Frequent Poster
Posts: 105
From:
Registered: MAR 2001
posted 05-31-2001 01:38 PM
--------------------------------------------------------------------------------
I decided to pick up the 23" Hg vacuum, since it was cheap, working, and wont have quite a big risk of implosion. Pyro, i didnt order the kits in parts, i got the whole thing from one of UGT's ebay auctions for $125 USD. Hmm, thats bad, my flasks are 250mL, 500mL, and 1000mL (i usually use the 500 and 250 for distilling) Guess ill have to order another 250mL. How common are implosions, and should i wrap every piece in tape?
C0de: i improvised some teflon sleeves with wideteflon tape, but acid vapors got under it and condensed there, eating the rubber.
Also, forgot to mention, its an oil-less pump. I dont know if that would mean i dont have to worry about a trap, because there would be no oil the vapors would contaminate?
[This message has been edited by John456 (edited May 31, 2001).]
no_name_available
New Member
Posts: 25
From: germany (?)
Registered: JAN 2001
posted 05-31-2001 07:35 PM
--------------------------------------------------------------------------------
if you dont use such strong pumps so that water wouldnīt evaporate at room temperature you should think about what will happen if pressure raise at the pumpīs site of the water trap...
PYRO500
Moderator
Posts: 1465
From: somewhere in florida
Registered: SEP 2000
posted 05-31-2001 07:43 PM
--------------------------------------------------------------------------------
uh, then you dont havve a vaccume anymore and water gets blown into the still.
John456
Frequent Poster
Posts: 105
From:
Registered: MAR 2001
posted 05-31-2001 09:38 PM
--------------------------------------------------------------------------------
Oh yeah, one last question to tack on to the huge list Would using flat bottomed flasks instead of round bottomed ones increase the risk of implosion?
10fingers
Frequent Poster
Posts: 411
From: USA
Registered: SEP 2000
posted 05-31-2001 10:02 PM
--------------------------------------------------------------------------------
Holy Shit! The flasks you have are not going to implode. This system is designed for vacuum distillations. If you don't want to listen to this advice then you can e-mail the manufacturer and ask them, I already did. Neither do you have to wrap the joints with teflon tape or put grease on them. If you were to rig up some type of vapor trap using glass then you would have to take precautions against implosions.
Teck
Frequent Poster
Posts: 146
From:
Registered: JAN 2001
posted 06-01-2001 02:58 AM
--------------------------------------------------------------------------------
John how much did you pay for the setup?
I want to make soe RDX and this is the only thing stopping me from doing it.
wantsomfet
Frequent Poster
Posts: 236
From: EU
Registered: JAN 2001
posted 06-01-2001 07:47 AM
--------------------------------------------------------------------------------
I learned to NEVER use flat bottomed flasks etc. with reduced pressure. Look in any good chemistry book. The pressure about 1000g/cm2 in a "normal" aspirator vacuum...
------------------
for best catfood visit:
kangaroooo.cjb.net
Bitter
Frequent Poster
Posts: 290
From: 11 Downing Street, London, England
Registered: SEP 2000
posted 06-01-2001 09:40 AM
--------------------------------------------------------------------------------
Will a really powerful vacuum cleaner be a sufficient alternative ? By how much (%) of one atmosphere does the pressure need to be reduced by ? I have searched for this information, but nothing had turned up so far. It think it would help everyone if this value was known.
Plus, isn't there any danger of evaporating the nitric acid ? Surely the nitric boils at a higher pressure than water...
frostfire
Frequent Poster
Posts: 266
From:
Registered: SEP 2000
posted 06-01-2001 09:51 AM
--------------------------------------------------------------------------------
how exactly in the process do you start the vacuu pump; just as the mixture start boiling or throughout the whole process..?
What I mean is if the pressure inside the apparatus goes far below 1 atm then is it possible the glass won't hold anymore and break (implosion) ???
wantsomfet
Frequent Poster
Posts: 236
From: EU
Registered: JAN 2001
posted 06-01-2001 10:03 AM
--------------------------------------------------------------------------------
First evacuate the apparature, adjust the vacuum and then start heating.
After the distillation is finished, remove the heat source, let the apparature cool down a bit and then slowly release the vacuum.
SEE ATTACHED IMAGE or go to http://internettrash.com/users/altreal/img65.gif
------------------
for best catfood visit:
kangaroooo.cjb.net
frostfire
Frequent Poster
Posts: 266
From:
Registered: SEP 2000
posted 06-01-2001 02:10 PM
--------------------------------------------------------------------------------
thx a million
I believe d&e are the vacuum parts (what're they?)
and how does it work at e&f (the cold trap; prevent acid vapor get to the pump????)
Anthony
Moderator
Posts: 2306
From: England
Registered: SEP 2000
posted 06-01-2001 09:31 PM
--------------------------------------------------------------------------------
Just a little add-on, if you switch the vaccum on as the contents of the retort starts to boil then it will flash boil and shoot through your apparatus
Teck
Frequent Poster
Posts: 146
From:
Registered: JAN 2001
posted 06-01-2001 09:47 PM
--------------------------------------------------------------------------------
Whats the yeild in nitric acid when using a vaccum and when your not using a vaccum?
Lagen
Frequent Poster
Posts: 174
From:
Registered: MAY 2001
posted 06-01-2001 09:49 PM
--------------------------------------------------------------------------------
IMHO using any type of grease on the joints not only does not help anything but is downright dangerous with high conc. HNO3.
John456
Frequent Poster
Posts: 105
From:
Registered: MAR 2001
posted 06-01-2001 09:53 PM
--------------------------------------------------------------------------------
I got 62mL nitric acid using 100g H2SO4 and 105g KNO3 yesterday without a vacuum. I think thats a bad yield though. Im hoping to try it under a vacuum tomorrow.
Teck: I payed $125 for the whole set which included: 500mL round-bottom flask, 1000mL round-bottom flask, 3-way distilling adapter, thermometer adapter with o-ring and bushing, 200mm Liebig condenser, and vacuum adapter.
Lagen: Silicon grease wont react with HNO3 and it does help reduce leaks.
Frequent Poster
Posts: 105
From:
Registered: MAR 2001
posted 05-30-2001 05:28 PM
--------------------------------------------------------------------------------
Hey,
Decided to buy some jointed glassware anyway since i wont have to deal with stoppers and can use it for vacuum distillation. The stuff i bought has 24/40 joints and looks like this:
I am thinking of buying an oil vacuum pump so i can make high concentration nitric acid among other things, and have a few questions before i do. Number one, can i just hook the pump directly up to the vacuum adapter, or would i need something to prevent gas and liquid from going into the pump? Also, does anyone have a web page or can provide any info on which model pumps are suitable for distillation, pricing, etc? On a related note, would i need any sort of special clamps to hold the joints together and prevent leaks, or will grease work fine?
Thanks! -John
[This message has been edited by John456 (edited May 30, 2001).]
PYRO500
Moderator
Posts: 1465
From: somewhere in florida
Registered: SEP 2000
posted 05-30-2001 06:24 PM
--------------------------------------------------------------------------------
I would get a bubbler just to make sure the nitric acid reminant vapors dont ruin the pump
10fingers
Frequent Poster
Posts: 411
From: USA
Registered: SEP 2000
posted 05-30-2001 07:17 PM
--------------------------------------------------------------------------------
Did you get this from U.G.T? I have one that looks identical to it. You do need a trap to keep acid vapors from going into the pump.
I have a refrigeration type vacuum pump. There is a aspirator type pump that hooks up to your faucet. There about $10.00 at Pyrotek. With them you would not need any type of trap for vapors but I have never tried one so I do not know if they would supply enough vacuum for what you want to do.
I have been able to obtain a high vacuum without using any kind of joint grease.
John456
Frequent Poster
Posts: 105
From:
Registered: MAR 2001
posted 05-30-2001 07:37 PM
--------------------------------------------------------------------------------
Yes, it was from UGT Damn, how much does a trap run and where can i get one? I already have an aspirator and the vacuum is not even worth using. What would be the purpose of the bubbler Pyro? Recycling the vapors back into the liquid?
Edit: A trap is a sort of condensor cooled by liquid Nitrogen or solid CO2 right? If so i can probably make one, but i dont know if i want to risk it since vacuum pumps are quite expensive. Also, when people say "X Inches of Mercury" what does that measure? Would 23" of Hg be suitable for distillation?
[This message has been edited by John456 (edited May 30, 2001).]
PYRO500
Moderator
Posts: 1465
From: somewhere in florida
Registered: SEP 2000
posted 05-30-2001 09:11 PM
--------------------------------------------------------------------------------
b trap we mean somethign to keep the vapors away form the pump, It dosent have to use cold temps, That is a cold trap. what I was taloking about is something like this:
glassware ======|| ||===========vacuume pump tubes || || -^^^^^^^^- | ! ! | | ! | Water |--------| | ! o oo | | ! o o | ----------
the water absorbs harmful vapors from reaching the pump.
this U.G.T do they have a page on the web?
there I fixed it
[This message has been edited by PYRO500 (edited May 30, 2001).]
John456
Frequent Poster
Posts: 105
From:
Registered: MAR 2001
posted 05-30-2001 09:23 PM
--------------------------------------------------------------------------------
The picture kinda got messed up in the posting but i think i see what it was supposed to look like. Sort of like a bottle of water between the vacuum and the glassware , right? this seems like it could be easily made. UGT's page is www.unitedglasstech.com , but check out their auctions on ebay, they have the same stuff they are selling their for a lot less.
John456
Frequent Poster
Posts: 105
From:
Registered: MAR 2001
posted 05-30-2001 10:43 PM
--------------------------------------------------------------------------------
Ahh, i see. That can be easily made. My next question is: Will a vacuum pump that can pull 23" of mercury be good for distillation?
PYRO500
Moderator
Posts: 1465
From: somewhere in florida
Registered: SEP 2000
posted 05-30-2001 10:56 PM
--------------------------------------------------------------------------------
can you list the part numbers of the stuff you ordered? I am also looking into setting up a general purpose distillation rig for making nitric acid with amonnium nirtate and H2SO4. their prices at u.g.t are pretty good too.
10fingers
Frequent Poster
Posts: 411
From: USA
Registered: SEP 2000
posted 05-30-2001 11:31 PM
--------------------------------------------------------------------------------
I was having the same problems with acid vapors getting into my pump and ruining the oil. I tried a water trap but the water readily evaporates at low pressure and that gets into your oil. I am now using 2 in.x 8 in.piece of pvc pipe with hose fittings on each end. The pipe is filled with baking soda. There are several layers of filter paper in the pipe to prevent the baking soda from being sucked into the pump. I have only used this two times and it seems to be working. The soda would have to be replaced periodically.
The pump I have is a refrigeration type which I picked up at a pawn shop for $30.00, it is capable of pulling 30 in. of vacuum, but It seems the whole system works better at around 15 or 20 in. At high vacuum there is a tendency for the mixture to erupt and spill over into the condenser.
PYRO500
Moderator
Posts: 1465
From: somewhere in florida
Registered: SEP 2000
posted 05-30-2001 11:48 PM
--------------------------------------------------------------------------------
I was thinking of using one of those nitro fuel pumps (for use in nitrus oxide car systems) it can presurize fuel to 100 psi, I was thinking of using one in a water aspirator? do you think it would work?
nbk2000
Moderator
Posts: 1096
From: Guess
Registered: SEP 2000
posted 05-31-2001 12:44 AM
--------------------------------------------------------------------------------
You can't use a water trap in a high vacuum system because the water boils off at room temperature or less. It's been ages since I last dealt with such things so I don't know what you could use to catch the nitric vapors besides a cold trap.
But, I can tell you that grease and pure nitric equals bad! If the grease is silicon, than that should be OK. Wrap the joints with several layers of teflon tape to prevent acid vapors leaking out, and clips aren't needed if your support clamps are properly set up.
Since you'll be using vacuum, be sure all exposed glassware, especially the flasks, are checked for cracks and scratchs, and wrapped with tape and emplaced in a sturdy container that will contain the glass and acid in case of implosion, which is a common occurance during vacuum work.
PYRO500
Moderator
Posts: 1465
From: somewhere in florida
Registered: SEP 2000
posted 05-31-2001 01:16 AM
--------------------------------------------------------------------------------
what about a commercial vapor drying and netrulizing trap tube avalible from chromatagraphy supply companys
-A-
Frequent Poster
Posts: 100
From:
Registered: JAN 2001
posted 05-31-2001 01:50 AM
--------------------------------------------------------------------------------
John456, that's almost the same setup I am waiting for...no money yet, you are a lucky guy. A trap bottle is just that, generally a bottle filled with water, a stopper with two holes and a tube in each hole. I suggest that you put the trap bottle in a mix of ice and salt to keep the water cool and prevent boiling. A good vacuum pump costs a lot, too much for me. A water aspirator can be used instead. Make sure you are using thick tubing. Oh, and from the picture I can't see what's the volume of the flasks, but I advise against using anything bigger than 250ml as an implosion can occur.
c0deblue
Frequent Poster
Posts: 229
From:
Registered: JAN 2001
posted 05-31-2001 03:34 AM
--------------------------------------------------------------------------------
A quite respectable vacuum pump can be improvised from an old refrigerator compressor. Just be sure to get everything with it you need when removing it from the junked unit, and cut the tubing long enough so you'll have something to work with. These are pretty efficient, and most can draw down to almost 30" Hg - a LOT stronger than needed for HNO3 distillation.
Does anyone know whether teflon sleeves for rubber stoppers (or rubber-filled teflon stoppers) are available anywhere?
John456
Frequent Poster
Posts: 105
From:
Registered: MAR 2001
posted 05-31-2001 01:38 PM
--------------------------------------------------------------------------------
I decided to pick up the 23" Hg vacuum, since it was cheap, working, and wont have quite a big risk of implosion. Pyro, i didnt order the kits in parts, i got the whole thing from one of UGT's ebay auctions for $125 USD. Hmm, thats bad, my flasks are 250mL, 500mL, and 1000mL (i usually use the 500 and 250 for distilling) Guess ill have to order another 250mL. How common are implosions, and should i wrap every piece in tape?
C0de: i improvised some teflon sleeves with wideteflon tape, but acid vapors got under it and condensed there, eating the rubber.
Also, forgot to mention, its an oil-less pump. I dont know if that would mean i dont have to worry about a trap, because there would be no oil the vapors would contaminate?
[This message has been edited by John456 (edited May 31, 2001).]
no_name_available
New Member
Posts: 25
From: germany (?)
Registered: JAN 2001
posted 05-31-2001 07:35 PM
--------------------------------------------------------------------------------
if you dont use such strong pumps so that water wouldnīt evaporate at room temperature you should think about what will happen if pressure raise at the pumpīs site of the water trap...
PYRO500
Moderator
Posts: 1465
From: somewhere in florida
Registered: SEP 2000
posted 05-31-2001 07:43 PM
--------------------------------------------------------------------------------
uh, then you dont havve a vaccume anymore and water gets blown into the still.
John456
Frequent Poster
Posts: 105
From:
Registered: MAR 2001
posted 05-31-2001 09:38 PM
--------------------------------------------------------------------------------
Oh yeah, one last question to tack on to the huge list Would using flat bottomed flasks instead of round bottomed ones increase the risk of implosion?
10fingers
Frequent Poster
Posts: 411
From: USA
Registered: SEP 2000
posted 05-31-2001 10:02 PM
--------------------------------------------------------------------------------
Holy Shit! The flasks you have are not going to implode. This system is designed for vacuum distillations. If you don't want to listen to this advice then you can e-mail the manufacturer and ask them, I already did. Neither do you have to wrap the joints with teflon tape or put grease on them. If you were to rig up some type of vapor trap using glass then you would have to take precautions against implosions.
Teck
Frequent Poster
Posts: 146
From:
Registered: JAN 2001
posted 06-01-2001 02:58 AM
--------------------------------------------------------------------------------
John how much did you pay for the setup?
I want to make soe RDX and this is the only thing stopping me from doing it.
wantsomfet
Frequent Poster
Posts: 236
From: EU
Registered: JAN 2001
posted 06-01-2001 07:47 AM
--------------------------------------------------------------------------------
I learned to NEVER use flat bottomed flasks etc. with reduced pressure. Look in any good chemistry book. The pressure about 1000g/cm2 in a "normal" aspirator vacuum...
------------------
for best catfood visit:
kangaroooo.cjb.net
Bitter
Frequent Poster
Posts: 290
From: 11 Downing Street, London, England
Registered: SEP 2000
posted 06-01-2001 09:40 AM
--------------------------------------------------------------------------------
Will a really powerful vacuum cleaner be a sufficient alternative ? By how much (%) of one atmosphere does the pressure need to be reduced by ? I have searched for this information, but nothing had turned up so far. It think it would help everyone if this value was known.
Plus, isn't there any danger of evaporating the nitric acid ? Surely the nitric boils at a higher pressure than water...
frostfire
Frequent Poster
Posts: 266
From:
Registered: SEP 2000
posted 06-01-2001 09:51 AM
--------------------------------------------------------------------------------
how exactly in the process do you start the vacuu pump; just as the mixture start boiling or throughout the whole process..?
What I mean is if the pressure inside the apparatus goes far below 1 atm then is it possible the glass won't hold anymore and break (implosion) ???
wantsomfet
Frequent Poster
Posts: 236
From: EU
Registered: JAN 2001
posted 06-01-2001 10:03 AM
--------------------------------------------------------------------------------
First evacuate the apparature, adjust the vacuum and then start heating.
After the distillation is finished, remove the heat source, let the apparature cool down a bit and then slowly release the vacuum.
SEE ATTACHED IMAGE or go to http://internettrash.com/users/altreal/img65.gif
------------------
for best catfood visit:
kangaroooo.cjb.net
frostfire
Frequent Poster
Posts: 266
From:
Registered: SEP 2000
posted 06-01-2001 02:10 PM
--------------------------------------------------------------------------------
thx a million
I believe d&e are the vacuum parts (what're they?)
and how does it work at e&f (the cold trap; prevent acid vapor get to the pump????)
Anthony
Moderator
Posts: 2306
From: England
Registered: SEP 2000
posted 06-01-2001 09:31 PM
--------------------------------------------------------------------------------
Just a little add-on, if you switch the vaccum on as the contents of the retort starts to boil then it will flash boil and shoot through your apparatus
Teck
Frequent Poster
Posts: 146
From:
Registered: JAN 2001
posted 06-01-2001 09:47 PM
--------------------------------------------------------------------------------
Whats the yeild in nitric acid when using a vaccum and when your not using a vaccum?
Lagen
Frequent Poster
Posts: 174
From:
Registered: MAY 2001
posted 06-01-2001 09:49 PM
--------------------------------------------------------------------------------
IMHO using any type of grease on the joints not only does not help anything but is downright dangerous with high conc. HNO3.
John456
Frequent Poster
Posts: 105
From:
Registered: MAR 2001
posted 06-01-2001 09:53 PM
--------------------------------------------------------------------------------
I got 62mL nitric acid using 100g H2SO4 and 105g KNO3 yesterday without a vacuum. I think thats a bad yield though. Im hoping to try it under a vacuum tomorrow.
Teck: I payed $125 for the whole set which included: 500mL round-bottom flask, 1000mL round-bottom flask, 3-way distilling adapter, thermometer adapter with o-ring and bushing, 200mm Liebig condenser, and vacuum adapter.
Lagen: Silicon grease wont react with HNO3 and it does help reduce leaks.