Author Topic: first encouraging ketenelamp experiment  (Read 5113 times)

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foxy2

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Re: first encouraging ketenelamp experiment
« Reply #20 on: February 27, 2002, 02:47:00 PM »
Here is some good information on purification

Patent US5264087


Patent US4737318


This is ok

Patent US4107002



here is a brute force method for acetic and propionic anhydrides

Patent US2872481


Patent US2160842



An interesting thought from above patents.
You could make acetic anhydride by refluxing GAA in a pressurized system while passing the reflux stream over a bed of silica gel.  You just need to design a pressureized refluxer(easier said than done), this would give you easy small batches of acetic anhydride. 
 
Other stuff

Patent US1915573


Patent US1815802



This could give you some ideas

http://www.chemeng.ed.ac.uk/~neilm/new/azeotope/AA.html


Who knows if acetic anhydride forms azeotropes

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hypo

  • Guest
Re: first encouraging ketenelamp experiment
« Reply #21 on: February 27, 2002, 03:39:00 PM »
thanks a lot! that's interesting reading material.

i especially like the fact that you probably can separate AA/GAA using a toluene/water system. let's see...

i'm also pretty much convinced that the volume increase came mainly from acetone vapors that were carried with the ketene.

MMM

  • Guest
Re: first encouraging ketenelamp experiment
« Reply #22 on: March 01, 2002, 04:41:00 AM »
? Toluene/water system, if you are thinking of extracting AA into Toluene and the acetic acid into the water.  Consider the solubility of water in Toluene and the reaction of water with AA :(   Sorry.

Toluene forms azeotrope with water, BP 85C, 20%H2O

Swim had good recovery of AA by using refractionating column, initial distillation mixed with Acetic, then temp rose to proper 140C, the AA was then reused in next iteration with no problems.

MMM

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foxy2

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Re: first encouraging ketenelamp experiment
« Reply #23 on: March 01, 2002, 05:36:00 AM »
MMM
Read those patents

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hypo

  • Guest
Re: first encouraging ketenelamp experiment
« Reply #24 on: March 01, 2002, 12:24:00 PM »

Consider the solubility of water in Toluene and the reaction of water with AA :(   Sorry.




yep, i had the same considerations. but apparently AA reacts only slowly with water when cold. unfortunately fractionating is not a possibility right now.

btw:

- the acetone trap proved very useful (the collected acetone is really dirty (dark brown/red), what's that??).
- also it was noted that fast ketene bubbling is the way to go. this way you increase the keten/acetone ratio and the reaction is nicely exothermic (and you're finished sooner, of course). you probably can even notice 100% conversion, when the reaction is no longer exothermic.
- burning the excess ketene/CH4 worked good by piping the ketene in the flame of a camping cooker. good ventilation was still needed.


Osmium

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Re: first encouraging ketenelamp experiment
« Reply #25 on: March 01, 2002, 01:00:00 PM »
hypo, can you please measure the wire diameter and guesstimate the needed current?

I'm not fat just horizontally disproportionate.

hypo

  • Guest
Re: first encouraging ketenelamp experiment
« Reply #26 on: March 01, 2002, 07:18:00 PM »
this data comes from the producer of the wire:

diameter: 0.5mm
resistance: 5.6ohm/m

another wire will be tested in the course of the weekend.

the variac was going at about 40%-45% of it's power on a 230V socket. i have no idea what that means and no ohm- or amperemeter is available

hypo

  • Guest
Re: first encouraging ketenelamp experiment
« Reply #27 on: March 02, 2002, 10:21:00 AM »
every wire does not work  :(

the cheap one made it for about 3 seconds before disintegration.

uemura

  • Guest
Re: first encouraging ketenelamp experiment
« Reply #28 on: March 02, 2002, 10:33:00 AM »
Hi hypo,

thanks for the pic you PM-ed Uemura. If you want, Uemura could upload it to have it available to all Hive bees.
Successful weekend!


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uemura

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Re: first encouraging ketenelamp experiment
« Reply #29 on: March 03, 2002, 10:06:00 AM »
On request by hypo Uemura loaded this one up.
every wire does not work    But this one does: (Copyright Hypo)


Carpe Diem

Chromic

  • Guest
Re: first encouraging ketenelamp experiment
« Reply #30 on: March 03, 2002, 07:29:00 PM »
>can someone describe the smell of AA?

IIRC, smells similar to GAA but I've never really taken a close whiff of it.

>the resulting mixture was distilled. unfortunately the experimentator was
>not able to get clean fractions, so he took 3 broad fractions

Fractionally distilled? What length of a column did you use?

>the gas will then be piped directly into a flame. it contains methane, so
>burning should be pretty complete.

This could be dangerous and doesn't help the need for ventilllation. I suggest you run a length of tubing to out of your residence if you don't have a fumehood.

Btw, I love the simplicity of this. I read your post on version 2 a number of times, but for the life of me can't understand how the apparatus is arranged differently. I think I get version 1: you had a flask on a water bath connected to a claisen that has a wire running down in the centered hole then a water condenser on the offset hole using an gas adapter on the top piped to say a filter flask with GAA then the tubing vented out the window?

The cool thing is you could use a 600W dimmer and any 30 ohm length of nichrome wire (V=IR, P=IV... R=V^2/P, R=(120)^2/500W, R=28.8 ohm)... and everything is easy to find/adapt and OTC, well, except the wire... anyways, very cool.

hypo

  • Guest
Re: first encouraging ketenelamp experiment
« Reply #31 on: March 03, 2002, 08:17:00 PM »

> IIRC, smells similar to GAA but I've never really taken a
> close whiff of it.

yes, it produces the same "stench" in the nose, but the "smell" is quite different. strangely sweetish. otoh, this could be some impurities?

> Fractionally distilled? What length of a column did you
> use?

no column was used. but the real problem was that the yield sucked. the second try, with less GAA, acetone trap and vivid bubbling gave a nice AA fraction at 138-140° even without column, a fraction from 119-138° (for reuse) and a somewhat mysterious yellow forerun in the range of 80-90° (trashed).



> This could be dangerous and doesn't help the need for
> ventilllation.

well, it worked. i think there is no great danger, as there is no oxygen in the aparatus. the problem with piping the excess ketene outside of your house is that better nobody catch you doing it! clandestine chemistry is one thing, producing a gas as toxic as a wargas another.

> I read your post on version 2 a number of times, but
> for the life of me can't understand how the apparatus is
> arranged differently.

you described the first one very well. now instead of piping the gas directly through GAA, it is piped into the top of another condensor, which sits in the center hole of another claisen which again sits on a rb flask, preferably sitting in an ice bath. the second arm of this claisen is connected to a gas adapter, which is connected via tubing to the washing bottle with GAA. this is necessary to catch the acetone that gets carried with the ketene/CH4 mixture and which is a bitch to get out. i don't know if stacking 2 condensors is as effective, but i know that this setup worked very well.

> and OTC, well, except the wire

the wire was bought in a big (european) electronics place. can't get more OTC than that.

Chromic

  • Guest
Re: first encouraging ketenelamp experiment
« Reply #32 on: March 04, 2002, 12:00:00 AM »
I'm an OTC nut and this sounds like fun. I'd love to try this project someday, thank you for the explanations!

lugh

  • Guest
Re: first encouraging ketenelamp experiment
« Reply #33 on: March 04, 2002, 12:53:00 AM »
This may bee helpful if it can bee found  :)

The whole book (135 pages) is devoted to a worked example of how to design an entire plant for the production of Acetic Anhydride by thermal cracking of Acetone, and it includes Acetone Distillation Unit.

The manufacture of Acetic Acid, published by The Institution of Chemical Engineers, London. It was published in September 1961.

MMM

  • Guest
Re: first encouraging ketenelamp experiment
« Reply #34 on: March 11, 2002, 05:51:00 PM »
I knew I had come across a calculator for nichrome wire sometime.  :)  Hehe, UTFSE by all means, but dont forget the everyday engines either, www.google.com is great.

http://www.wiretron.com/free.html



Nearly forgot, you'll need this too

http://www.wiretron.com/nicrdat.html



HTH somebee's experiments, MMM



When the day is bad,and life's a curse
CHEER UP!!! Tomorrow may be Worse!!
('HAGAR' Comic)

Mountain_Girl

  • Guest
Re: first encouraging ketenelamp experiment
« Reply #35 on: March 12, 2002, 07:27:00 AM »
Hypo:

I echo Chromic's admiration for this project.

A bit of info on industrial AA distillation (from rctn of ketene with GAA) which may or may not be useful:

"Pure Anhydride Distillation

The raw anhydride can be distilled either continuously or discontinuously. In discontinuous distillation, three fractions are obtained:

Forerun (1 %) is about 40 % acetic acid; the rest consists of volatile liquids, particularly methyl acetate and acetone.
Middle run (about 10 %). Depending on the quality of the column, it contains 30 – 60 % acetic anhydride; the rest is acetic acid.
Pure Anhydride. Using discontinuous distillation at normal pressures, the purity of the anhydride cannot exceed 99 % (the remainder is acetic acid) because, at the still temperature required, a certain amount of decomposition occurs. These difficulties can be overcome by operating under reduced pressure.

For continuous distillation, two or three columns are used, depending on the required number of fractions (forerun and middle run are separated). The middle run portion is returned to the reactor as reagent acid. The residue of the distillation contains small amounts of tarry products and is worked up continuously in a Sambay evaporator."


Acetyl

  • Guest
second encouraging ketene lamp experiment
« Reply #36 on: April 12, 2002, 07:47:00 AM »
I would like to say thanks to "hypo" for realizing that building a ketene lamp is easy, "rhodium" for making this place possible, and "chromic" for the idea of using a dimmer, "uemura" for posting the picture from hypo and Organic Synthesis for mentioning this method.



The production of heroin requires acetic anhydride and getting my hands on it has always seemed either too risky or nearly impossible until that message (not that I would ever make it, but that a FOAF is interested). So I went out and got:

- nichrome wire from a hobby store ($2) (~1.2m?, ~32swg?)
- multimeter from the automotive section in a department store ($10)
- 600W dimmer from a hardware store ($4)
- detachable "bullet" connectors from electronics store ($4)
- #5 rubber stopper, four screws, piece of wood, one two wire extension cord, one three wire extension cord, some glass / heating equipment / clamps.

I tested the wire with the multimeter, 26 ohms. That looked fine to me. Two screws were put through the #5 stopper. The screw tips are attached to the ends of the nichrome wire that was formed into a spiralling loop by carefully wrapping it around a glass rod. The ends of the screws are attached to the two-wire extension cord. The ends of that cord are crimped with the connectors, as are all the other connections. This is done so the whole thing can be easily taken apart, updated or whatever. One side is attached to a dimmer, the other to the 3-wire extension cord. The other contact of the dimmer is attached to the extension cord. The ground of the dimmer is attached to the ground of the extension cord. The dimmer is screwed onto the hunk of wood. This completes the pyrolysis thingy.

Everything else is set up like hypo described. Acetone is boiling in a flask on a water bath. Pyrolysis thingy in the central neck of a Claisen. Condenser on the other neck. Gas outlet adapter to some tubing going into the solvent, the excess fumes going out the window.

I learned the following:

1) it really was TRULY a COMPLETELY UNNERVING EXPERIENCE turning on the power to pyrolyze the acetone. But it lit up no problem and ran smoothly. I was FREAKING OUT for no reason.

2) The gas generation is easily controlled by the dimmer.

3) for the test run I was just bubbling it through water for a few minutes... well, disconnecting it I noticed two scents, one was of acetic acid the other was of something burning. The apparatus works, which is awesome. Not so awesome is that the black rubber laboratory stopper was starting to crack and there's sort of a brownish-black tar area on the claisen adapter just below the stopper that built up as the ketene lamp ran.

For reasons of safety, I might never pursue this. It was unnerving, but the method sure does work.




improving the bowel movements of cats & dogs everywhere...

foxy2

  • Guest
fire risk
« Reply #37 on: April 12, 2002, 09:32:00 AM »
So how much fire/explosion risk is there?
Is that why hypo has not been posting lately? :o

Or is it because the synth worked so well and he's too high? :)


Those who give up essential liberties for temporary safety deserve neither liberty nor safety

LaBTop

  • Guest
Umm,
« Reply #38 on: April 12, 2002, 11:49:00 PM »
Hypo, please insert a safety device in front of that burning flame.
Simple, make a glasstube completely filled with very fine RED copper turnings or wire, this will directly extinguish any sucked back flame! This could happen when you have a pressure drop inside. LT/

WISDOMwillWIN

hypo

  • Guest
nice!
« Reply #39 on: April 13, 2002, 11:05:00 AM »
acetyl:

very cool! - i like the fact that 36swg seems to work too (which is considerably thinner than the 0.5mm (about 24swg) used by my experimenter). more choice is allways good. some endurance test would be very interesting. i'll try and push my experimenter to get 2 multimeters. also i'd really like to know how current, length of wire and strength of wire relate to the amount of ketene produced. is there any easy way to measure that?

i figure that this was a proof of concept - if you want to pursue your way to AA, don't forget to add an acetone trap, i think no standard lab condenser is able to condense all of the acetone out of the hot ketene / ch4 mixture. also seal the rubber stopper with a good deal of PTFE tape _and_ use good ventillation.

the thing with the stopper is strange - the grey rubber stopper you see in the picture some posts above did not suffer at all even after 5 hours of operation. the plastic connectors on the outside melted and the bottom of the stopper got brown, but this was more linked to the agressive atmosphere than to heat. maybe because the Cu wires are longer or better a removing heat? or the quality of the grey stopper is simply better?

the smell - i think you simply smelled the ketene. the AA will smell that way too. (the experimenter is distilling the AA through the same condensor he uses to condense the acetone vapours, maybe he shouldnt do that...)

foxy:

there seems to be no great danger once all air is replaced by acetone vapors inside the lamp. and you know how easy it is to reflux acetone - 5 minutes on oil bath and you can start. also overheating seems to be no problem. once the experimenter accidentially turned the knob of the variac to the far right and the wire simply disintegrated, but otherwise nothing happened.

labtop:

i promise that the next time there will be a U shape drying tube (the only one available) with copper turnings between flame and apparatus. suckback never happened once, because fast bubbling seems like the way to go. only the current going off could be a problem. wouldn't a washing bottle filled with water do the trick too?