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Author: Subject: My Chloral Hydrate Synth
XeonTheMGPony
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[*] posted on 1-3-2021 at 08:35
My Chloral Hydrate Synth


Hello, after reading up on all the threads here, and online I finally did a run for chloral hydrate with DDT as an end point goal for some of it

There are a good number of write ups but non with graphics or procedural write up, so I will try and fix this.

Pre-notes:

You will notice I did not go by the conventional method of adding HCL solution to my ethanol, and I'm not strong on the math, so others feel free to correct where required

Step 1:
Ethanol. Several bottles of acetone free nail polish remover where purchased, these where then care fully fractionally distilled to isolate the ethyl Acetate, This was then again fractionally distilled, discarding 10ml of the for run and post run to ensure good isolation.

This is then hydrolyzed with a slight excess of sodium hydroxide to yield Dry Ethanol, this is further worked up to purify it further by reacting with magnesium and refluxing, then distilling and swirling over cool sulfuric acid, then potassium hydroxide for a final distillation to a 500ml 3 necked flask (I meant to place a link to the PDF on the chemical purification step, I have misplaced this)

Assembly of reactor

The 3 necked flask is placed in an ice bath with a bubbler tube set in the farthest neck, reflux condenser on the center one and a thermo adapter on the last side neck and a stir bar, stirring is started in both the ice bath and flask.

Total volume of dry pure ethanol is 150ml (118.38grams (2.57mole))

assembly 1.jpg - 300kB

Next assemble the chlorine Generator while the above system cools.

here is where things get messy, I started off using Calcium Hypochlorite powder and HCL, 200 grams of this was used in the beginning with less than ideal results, assuming it had nearly the rated potency I should have gotten at least 160+ grams of Chlorine gas!

chlorine generator.jpg - 140kB

I charged the generating flask with 100grams of the Ca(ClO2)2 to react with 250ml of HCL, but found all had reacted befor the HCl aliquot was used up, so second charge used 150 grams, same amount HCl

I then reassessed my method and switched to the TCCA method (TriChloro IsoCyanuric Acid) Which proved to be superior clean and smooth running Chlorine generator! 8 pucks where used, each puck weighing out at 50grams @ 232.41grams per mole, for one mole 3 mole of HCl is required, so 0.250L of HCl @ 6mol/l HCl = ? (I suck at the math side, just kept adding till the chlorine stopped coming over, 250ml seemed fairly dead on though)

So with that mess out of the way under ice cold conditions the first stage of chlorination begins, this point I did not bother with a wash bottle of the HCl as the small amounts of moisture was not a concern and any droplets would be captured as it ran through the addition funnels vent.

chlorination starting.jpg - 81kB lowtemp chlorination start.jpg - 100kB 20210221_124058.jpg - 86kB

An exotherm was noted and ice recharged to the bath as this stage ran the Alcohol developed a bi layer and took on a green color at first little to no off gassing occurred.

This stage was allowed to run till no new exotherm was noted and gas absorption slowed.

Ice was then allowed to melt, and then temp was raised at this point heavy HCl off gassing began the second it got much over 0c.

60c stage.jpg - 383kB 60c stage 2.jpg - 382kB

how ever the evidence of the 2 layers ceased and it became oily like texture, as the chlorine bubbled in it was rapidly absorbed and inside the apparatus appeared clear and the off gas tube a steady stream of HCl was emitted. After some time the bubbles of the Chlorine appeared to grow larger, at this point I started to increase the temp to the 90c stage, yet even more HCl was emitted (There is a great deal of it generated!). The reaction mass become thicker and more oil like, the HCl off gas now had an additional scent of apples to it (Aldahyde).


90c stage.jpg - 287kB 90c stage 2.jpg - 277kB 90c stage 3.jpg - 106kB

It is interesting to note the bluish tinge seen inside the reflux column!

Once a density of 1.4 is reached chlorine addition ceased. System was allowed to cool, one cool the unit was purged with air to vent out the HCL/Chlorine/Aldahyde Vaporous.

After cooling an equal volume of distilled sulfuric acid is added and thoroughly stirred in then allowed to settle, As this happens the chlorine generator, reflux column and other glass adapters are disassembled and cleaned. More HCl will be released! So keep the fume extractor on!

Once all the reaction glass wear has been cleaned and dried, the 500ml 3 neck flask is set up for simple distillation, the Chloral is then distilled off over the sulfuric acid to a clean receiver flask filled with an access mass of calcium carbonate sourced from white chalk.
Chalk reciever.jpg - 159kB

After every thing was distilled over @ 94 to 97c distillation was stopped (For my Altitude 2c must be subtracted from boiling points listed!)

From the chalk it is again Distilled carefully, Any thing below 95 was discarded (Some either was made during the acid distillation, so be mind full of ignition sources during the whole procedure)

This was distilled to dryness. Here we get our first signs of solid success!

A good sign.jpg - 291kB A good sign 2.jpg - 80kB

The condenser is rinsed with distilled water into the now distilled chloral (The Chloral will get very hot!) an excess of further distilled water is added to it, it is then charged into a 250ml round bottom flask and placed into a heating mantle, a Vigreux column is added and insulated, and a simple distillation head and Leibig condenser placed on to a receiver beaker. Heat is very slowly raised to the point for every 1 drip at the receiver, we get 8 drips reflux

It took 6h to distill 125ml slower is purer! so do not start if you do not have a long time to watch it!

last stage.jpg - 227kB last stage 2.jpg - 248kB

At this point we have done an acid distillation, a base distillation, and a water distillation! with very careful minding of temps and going painfully tediously slow (Remember, the slower the distillation the finer the resolution of the substance!)

So our reward and yield?

125ml of very clean Chloral hydrate!
done 2.jpg - 167kB done.jpg - 147kB

That is a smaller fraction I wanted to test crystallize, it takes a while for it to dry enough. As seen it will eventually and has a very pleasant odor.

Post Notes:
It took a long time to chlorinate, it was spread out over a couple days due to first poor results with the calcium hypochlorite, and the fact I ran out of it, TCCA is superior bang for the buck in terms of chlorine.

Stages where a bit hard to isolate, but doesn't seem to picky for the start of the temp phases so long as you ensure through chlorination in the cold stage, I didn't get much oxidation as I kept free air out of my apparatus (HCl Atmosphere) till the final point just befor disassembly.

I hope this helps others int heir quest.
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Benignium
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[*] posted on 1-3-2021 at 14:24


Awesome write up and an interesting synthesis! I've been wanting to do this myself for a long time.

Could you determine a melting point?

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Syn the Sizer
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[*] posted on 1-3-2021 at 21:36


Very cool, I was thinking of doing a chloral hydrate synth for the hell of it.

Syn'
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Metacelsus
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[*] posted on 2-3-2021 at 03:39


Very nice writeup!

If you're going for DDT, I think keeping the product as anhydrous chloral might be better, since that's the form that's needed for DDT synthesis.




As below, so above.
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XeonTheMGPony
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[*] posted on 2-3-2021 at 06:03


Quote: Originally posted by Metacelsus  
Very nice writeup!

If you're going for DDT, I think keeping the product as anhydrous chloral might be better, since that's the form that's needed for DDT synthesis.


Dam, well seems my melting point is way off, so think I still have too much Aldahyde in there, so may need to do more chlorinating, waiting to test Density and Sp (Specific gravity)

If I do I'll keep that in mind!
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XeonTheMGPony
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[*] posted on 5-4-2021 at 03:47


Ok so I re chlorinated it, Sp, Bp, are all in spec, I now have some over chlorinated heavy stuff smells totally different to the fraction that came off at expected temps via fractional distillation.

But now here is the frustrating part, neither will crystallize! I distilled this time as Chloral Hydrate, now this is sort of my first venture into organics, I have not yet looked into it as of yet, but could any one steer me into the direction as to looking about recovering the over Chlorinated fraction?
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Dr.Bob
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[*] posted on 5-4-2021 at 16:22


Very nice experimental. I have smelled choral before and does have an oddly nice smell. I need to try that one day, as the DDT might be handy for something. I only wish chlordane was as easy to make (we have termites here in NC that will eat everything if left alone for a short time). It might be well worth saving the choral as the aldehyde, but it may oxidize quickly if left alone, so I would use it quickly then. The hydrate should be stable for years, the sample I saw years ago was ancient.
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