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Author: Subject: Dioxane Synthesis Using Phosphoric Acid
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[*] posted on 30-7-2018 at 17:41
Dioxane Synthesis Using Phosphoric Acid


DIOXANE SYNTHESIS WITH PHOSPHORIC ACID REPORT.

So, first of all, everyone knows that you can make dioxane with ethylene glycol and sulfuric acid as NurdRage exposed in video (https://www.youtube.com/watch?v=9Zzrn-61XAY). But where I live (Argentina) it is impossible to obtain sulfuric acid, i can make it myself, but using it to then make dioxane does not convince me in the work involved. So I have tried to make Dioxane using another acid that is not strong but somewhat dehydrating and accessible to me. Phosphoric acid. So I did it and here is what I found. The Yield is on Dioxane Azeotrope.

BEST EXPERIMENT:

In a simple distillation apparatus, I mix 200ml of commercial grade Ethyelene Glycol (which is actually quite good!) And 30ml of commercial grade 85% phosphoric acid, with a stir bar and a HotPlate to put and distill, The distillate came over at a range of temperature between 80-120 degrees Celsius. Distillation takes time, but it is not slow. I recommend not isolating the equipment with aluminum foil because it distills more ethylene glycol, just let it work. I got a total of 200 ml of what I call First distillate (Yes ... Name everything: v) Okey to these I added 10 g of sodium bisulfate monohydrate and fractionated the mixture. I collected 19 ml at a temperature below 87 degrees. 94 ml at 87 degrees and a residue of 97 ml wass in the distillation flask. Yield of Dioxan Azeotrope is 53%.

NOTES

Here are some things i found experimentally.
_ Isolation of the apparatus to increase distillation rate is BAD, More Ethylene Glycol comes over.
_ More Phosphoric acid or less, is does not Improve yeild.
_ Adding 10ml of Water per 100ml of Fist Distilate helps a bit.
_ Big apparatus are detrimental to the reaction, as the distillation requires more temperature and these produces more Side-Products

OTHER EXPERIMENTS AND CHEMICAL NOTES

I tried using 50 ml of phosphoric acid and 200 ml of Ethylene Glycol Yield: 25,99%
Using 20 ml of phosphoric acid and 200 ml of ethylene glycol Yield 38,42%
200 ml Ethyelene Glycol 30 ml Phosphoric acid and Big aparatus (To heat the reaction to higer temps) Yield 24,86% with a lot of products boiling at T below 87 Degrees in Fractionation
Ethylene Glycol was Tech Grade, i distill it found it was very pure ! with very little water.
Phosphoric acid was 85% Food Grade. Crystal clear.
Apparatus was all Glass with Ground glass joints.

Hope these Helps anyone :)

[Edited on 31-7-2018 by Chem Science]

[Edited on 31-7-2018 by Chem Science]
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XeonTheMGPony
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[*] posted on 30-7-2018 at 17:51


Try using anhydrous Iron sulfate, this can be don in a continuous flow system (add more as it is reacted via addition funnel)
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[*] posted on 30-7-2018 at 18:06


Hey ! thanks for the Data :D Xeon TheMGPoney xD
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[*] posted on 30-7-2018 at 18:26


What about doing this on a larger scale by refluxing bisulfate or phosphoric acid with PEG?



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[*] posted on 30-7-2018 at 18:42


I too have been playing with dioxane synthesis. I actually have less phosphoric acid than sulfuric. I have had ok results with using sodium bisulfate and intend to pursue that route a bit further.

@Xeon
What is the rationale behind the iron sulfate? And why anhydrous? Is the aim to mop up the water as it is produced? How are you adding this with an addition funnel?
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[*] posted on 30-7-2018 at 18:57


Well, it happens that Sodium Bisulfate is a lot more expensive than Phosphoric acid here. That was my motivation for doing these. I will give it a try on the PEG and Phosphoric reaction at some time.
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[*] posted on 31-7-2018 at 07:45


Food-grade ethylene glycol? Who would make that? EG is toxic and not to be used in food.
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[*] posted on 31-7-2018 at 08:24


O MY GOD ... Sorry for that, yeah i know it's toxic. I Changed it :) Thanks xD
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[*] posted on 31-7-2018 at 09:40


Quote: Originally posted by XeonTheMGPony  
Try using anhydrous Iron sulfate, this can be don in a continuous flow system (add more as it is reacted via addition funnel)


Got a reference for that? I think its been mentioned on SM but I could not find it and failed to find it with google




[Edited on 31-7-2018 by wg48]




Borosilicate glass:
Good temperature resistance and good thermal shock resistance but finite.
For normal, standard service typically 200-230°C, for short-term (minutes) service max 400°C
Maximum thermal shock resistance is 160°C
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[*] posted on 31-7-2018 at 16:40


Quote: Originally posted by j_sum1  
I too have been playing with dioxane synthesis. I actually have less phosphoric acid than sulfuric. I have had ok results with using sodium bisulfate and intend to pursue that route a bit further.

@Xeon
What is the rationale behind the iron sulfate? And why anhydrous? Is the aim to mop up the water as it is produced? How are you adding this with an addition funnel?


it is the glycol you add as it is consumed via addition funnel, the iron sulfate is the catylest, Anhydrous is that what is specified in the paper in the other Dioxane threads.




Attachment: Dioxane excerpt from Elderfield's Heterocyclic Compounds volume 6.pdf (3.1MB)
This file has been downloaded 52 times

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[*] posted on 1-8-2018 at 02:43


Quote: Originally posted by XeonTheMGPony  


it is the glycol you add as it is consumed via addition funnel, the iron sulfate is the catylest, Anhydrous is that what is specified in the paper in the other Dioxane threads.


it is the glycol you add as it is consumed via addition funnel, the iron sulfate is the catylest, Anhydrous is that what is specified in the paper in the other Dioxane threads.

Attachment: Dioxane excerpt from Elderfield's Heterocyclic Compounds volume 6.pdf (3.1MB)

Thanks Xeon.

This is the ref. from that paper for the iron sulphate method: van alphen, Rec. trav, chim., 49, 1040 (1930)
I tried searching for it but found nothing relevant. Can anyone parse that reference in to a book or journal name and any additional information I may need to find it. Thanks in advance.





Borosilicate glass:
Good temperature resistance and good thermal shock resistance but finite.
For normal, standard service typically 200-230°C, for short-term (minutes) service max 400°C
Maximum thermal shock resistance is 160°C
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