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Author: Subject: oleum & SO3
softbeard
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[*] posted on 29-9-2017 at 17:19


Quote: Originally posted by clearly_not_atara  
I don't think anything can actually reverse the damage metaphosphoric acid does to glass... you can remove the phosphate, at least, with alkali. In the future consider preparing your HPO3 in stainless steel...


Yes, I agree. I ruined a large quartz test tube trying to boil phosphoric acid. Nothing can repair the damage.

Also, I tried to boil down concentrated phosphoric acid to HPO3 in a stainless steel dish. The result was a bubbling green mass along with visible corrosion to the stainless dish.
You might be better off to try cast iron to boil & dehydrate your phosphoric acid acid accept some corrosion.
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clearly_not_atara
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[*] posted on 29-9-2017 at 17:39


My bad. Steel is attacked. I believe some varieties of stainless may be more chemically resistant than others but acid-resistant stainless may not be standard for consumer products.

I found a reference in which porcelain is used. Perhaps clay is the way to go?

http://anonym.to/http://www.science-chemistry.com/preparatio...
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[*] posted on 30-9-2017 at 15:56


What is the appeal of using phosphoric acid to prepare oleum rather than simply cracking sodium bisulfate at 500 C or so?



This is my YouTube channel: Extreme Red Cabbage. I don't have much posted, but I try to do nice writeups once in a while.
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Magpie
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[*] posted on 3-10-2017 at 17:46


I think the main advantage is that you can use lower temperature. Garage chemist says heating to 680-880°C is needed for NaHSO4. I have done this using my tube furnace. With phosphoric acid/H2SO4 a bunsen burner can be used at something around the bp of H2SO4.

Incidentally my %yield at the 4X scale was approx 47%. I made another batch yesterday at scale 6X having a %yield of 50.7%.

Again, I will post some pictures if I can get this #$%& ing computer to assist me.

Attachment: 6X oleum1.odt (2MB)
This file has been downloaded 81 times

[Edited on 4-10-2017 by Magpie]




The single most important condition for a successful synthesis is good mixing - Nicodem
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[*] posted on 3-10-2017 at 18:08


Melgar: while it is certainly interesting that you can buy tosyl chloride on Amazon we have a relatively large number of questions from people who cannot simply buy things on Amazon. For them, metaphosphoric-acid -> oleum -> chlorosulfonate -> tosyl chloride is the most OTC preparation of tosyl chloride, I think.

Quote: Originally posted by JJay  
What is the appeal of using phosphoric acid to prepare oleum rather than simply cracking sodium bisulfate at 500 C or so?


It's my understanding that if you combine metaphosphoric acid and concentrated sulfuric acid you can obtain a solution containing dissolved SO3 (as polysulfates) without ever handling SO3 gas. This is useful because of the considerable risks associated with accidental release of the latter. It may be possible to use oleum containing phosphoric acid in some applications of oleum, such as the decomposition of citric acid to acetonedicarboxylic acid, or similar.

I'm less clear on how much such a solution has to be heated in order to produce a stream of SO3 gas. However, I suspect it is much lower than the ~400 C decomposition temperature of Na2S2O7. Since SO3 is already hard to handle it is nice not to have to handle it at 400 C! Producing SO3 (g) at lower temperatures makes it much easier to do everything that isn't making oleum, such as the formation of Py*SO3 and other similar complexes, since these may be unstable/char at very high temperatures.
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[*] posted on 4-10-2017 at 09:20


Quote: Originally posted by clearly_not_atara  
Melgar: while it is certainly interesting that you can buy tosyl chloride on Amazon we have a relatively large number of questions from people who cannot simply buy things on Amazon. For them, metaphosphoric-acid -> oleum -> chlorosulfonate -> tosyl chloride is the most OTC preparation of tosyl chloride, I think.

Probably. I just thought it would be helpful to point that out in case anyone needed it for anything. I've known it was available for a while, but never could come up with a reason to buy it. All the reactions that I'm aware of it being used in, also require a bunch of other stuff that's inaccessible to me.




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[*] posted on 4-10-2017 at 15:10


I made oleum at 10X scale today, 60g as predicted. I have about 125g of oleum now at 50% SO3. Thie should be enough to make a nice batch of thionyl chloride.

Anyone else having trouble loading pictures with Windows 10?

[Edited on 5-10-2017 by Magpie]

Attachment: 6X oleum1.odt (2MB)
This file has been downloaded 61 times





The single most important condition for a successful synthesis is good mixing - Nicodem
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NEMO-Chemistry
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[*] posted on 8-10-2017 at 06:27


Quote: Originally posted by Magpie  
I made oleum at 10X scale today, 60g as predicted. I have about 125g of oleum now at 50% SO3. Thie should be enough to make a nice batch of thionyl chloride.

Anyone else having trouble loading pictures with Windows 10?

[Edited on 5-10-2017 by Magpie]

I upgraded to win 10, i have no end of problems including pic problems. I have no idea of the solution, in the end i simply downloaded VM ware and installed windows 8.1 on a virtual machine. I find I use that more than win 10 now.

Win 10 is said to be much better than win 8.1, but personally i just cant get on with win 10.

This is the one i use, its free. kind of defeats the point in some ways, but might help you out

https://www.virtualbox.org/

[Edited on 8-10-2017 by NEMO-Chemistry]
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[*] posted on 8-10-2017 at 11:02


Quote: Originally posted by Magpie  
I made oleum at 10X scale today, 60g as predicted. I have about 125g of oleum now at 50% SO3. Thie should be enough to make a nice batch of thionyl chloride.

Anyone else having trouble loading pictures with Windows 10?

[Edited on 5-10-2017 by Magpie]


About your procedure: You mentioned some serious joint leakage.
Were the joints assembled dry, or were they wetted with concentrated H2SO4?

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[*] posted on 8-10-2017 at 13:46


Quote: Originally posted by NEMO-Chemistry  
Quote: Originally posted by Magpie  
I made oleum at 10X scale today, 60g as predicted. I have about 125g of oleum now at 50% SO3. Thie should be enough to make a nice batch of thionyl chloride.

Anyone else having trouble loading pictures with Windows 10?

[Edited on 5-10-2017 by Magpie]

I upgraded to win 10, i have no end of problems including pic problems. I have no idea of the solution, in the end i simply downloaded VM ware and installed windows 8.1 on a virtual machine. I find I use that more than win 10 now.

Win 10 is said to be much better than win 8.1, but personally i just cant get on with win 10.

This is the one i use, its free. kind of defeats the point in some ways, but might help you out

https://www.virtualbox.org/

[Edited on 8-10-2017 by NEMO-Chemistry]


I am having the same problem with my IOS i-pad so conclude it is related to the formum software limit of 8MGB for picture uploads. Funny I never had this problem before. I will try again after I reduce the picture bytes.

Hi swim,

I use con H2SO4 for joint sealant for Oleum. Evenually it still leaks after it starts boiling. I will try Krytox next.

[Edited on 8-10-2017 by Magpie]




The single most important condition for a successful synthesis is good mixing - Nicodem
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[*] posted on 8-10-2017 at 14:25


@Magpie

Damn.

Well, I need to rig up some kind of fume hood anyway. (Yes, I've been looking at the appropriate threads for ideas and advice)

Thanks for mentioning that leakage problem.

I'm sure it has saved some of us an unpleasant surprise.
Certainly has in my case.
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[*] posted on 8-10-2017 at 16:04


picture test

reduced size for vulture.jpg - 24kB

This works! Used Paint to reduce size of a picture that wouldn't post before resizing.

[Edited on 9-10-2017 by Magpie]




The single most important condition for a successful synthesis is good mixing - Nicodem
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[*] posted on 8-10-2017 at 16:21


Quote: Originally posted by Magpie  
I made oleum at 10X scale today, 60g as predicted. I have about 125g of oleum now at 50% SO3. Thie should be enough to make a nice batch of thionyl chloride.

Anyone else having trouble loading pictures with Windows 10?

[Edited on 5-10-2017 by Magpie]


Here's the picture I wanted to show showing a large amount of H2SO4 mist (smoke) being formed due to uneven cooling. I would heat with a heat gun to clear the condenser of frozen SO3 then when not enough SO3 was condensing I would turn on the ice water. When I held the condenser water at 11°C this smoke was nearly eliminated.



6x oleum3.jpg - 1MB

When the system is balanced only mild heating is required with the bunsen burner. No insulation of the pot or still head is needed. Under this condition there is virtually no SO3 leakage at the joints. The smoke seen above is due to irregular heating/cooling in the condenser and is spewing out the vacuum adapter tublature.

[Edited on 9-10-2017 by Magpie]

[Edited on 9-10-2017 by Magpie]




The single most important condition for a successful synthesis is good mixing - Nicodem
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Magpie
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[*] posted on 10-10-2017 at 19:46


new confirm test





[Edited on 11-10-2017 by Magpie]

test3.jpg - 23kB




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[*] posted on 19-11-2017 at 15:03


Quote: Originally posted by Magpie  
I made oleum at 10X scale today, 60g as predicted. I have about 125g of oleum now at 50% SO3.


I am in the final reagent preparation stage for making thionyl chloride and chlorosulfonic acid. As I never had an assay of the oleum I made I was skeptical that it was actually 50%. So I set out to measure its boiling point. This I determined to be 63°C which confirms a concentration of about 70%. This was very pleasing but I was skeptical so determined its mp using a salt brine coolant. This result was also very pleasing at -2°C, which confirms about 70%. I was also considering doing a titration but this is not necessary now.





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[*] posted on 19-11-2017 at 15:21


Serious stuff Magpie.

Excellent work, yet again.

From a 1673 alchemy parchment, the words/pictures deciphered as: "With the vitriolic dragon, take care to not touch it, lest it bite"




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