Sciencemadness Discussion Board

Arsenic and TCCA

6dthjd1 - 24-9-2022 at 11:34

Hello


If I let a "rock" of elemental Arsenic sit in TCCA for weeks will I likely get a very small yield of the AsCl3?

SplendidAcylation - 26-9-2022 at 02:33

Do you mean to let it sit in powdered TCCA, or a solution?

Either way, it seems like a crazy idea to me, why not just use the TCCA to generate chlorine gas, dry it, and pass it over the arsenic?
Sounds a lot more straight forward!

Boffis - 26-9-2022 at 07:58

I replied to this once before but my response seems to have been lost, so here again:

Native arsenic dissolves in sodium hypochlorite solution so in the presence of water it may well dissolve and in the presence of alkali I am sure it will dissolve giving arsenate ions. In the absence of water I suspect nothing will happen until you warm it; and then it may react rather violently. If you want to make arsenic trichloride generate the chlorine from the TCCA in a separate vessel, dry it by bubbling through conc. sulphuric acid and pass into a suspension of ground arsenic in say chloroform.

It may be possible to generate arsenic trichloride in conc. hydrochloric acid by suspending the arsenic in it, adding TCCA slowly to it and then extracting the chloride with a suitable solvent (DCM or chloroform possibly) and then separate the final product by fractional distillation, but this is only conjecture. Arsenic trichloride is hydrolysed in aqueous solution to arsenic trioxide and hydrochloric acid in water.

6dthjd1 - 26-9-2022 at 09:55

Quote: Originally posted by SplendidAcylation  
Do you mean to let it sit in powdered TCCA, or a solution?

Either way, it seems like a crazy idea to me, why not just use the TCCA to generate chlorine gas, dry it, and pass it over the arsenic?
Sounds a lot more straight forward!



yes to let it sit on the TCCA

Lionel Spanner - 26-9-2022 at 11:39

The easiest way to make arsenic trichloride from elemental arsenic is combining it with chlorine at 80-85 °C.
Source - https://onlinelibrary.wiley.com/doi/10.1002/14356007.a03_113...

If you try running the reaction at room temperature with hardly any free chlorine, it's likely to be extremely slow, assuming it occurs at all.

[Edited on 26-9-2022 by Lionel Spanner]

6dthjd1 - 27-9-2022 at 00:44

Quote: Originally posted by Lionel Spanner  
The easiest way to make arsenic trichloride from elemental arsenic is combining it with chlorine at 80-85 °C.
Source - https://onlinelibrary.wiley.com/doi/10.1002/14356007.a03_113...

If you try running the reaction at room temperature with hardly any free chlorine, it's likely to be extremely slow, assuming it occurs at all.

[Edited on 26-9-2022 by Lionel Spanner]


I hope Arsenic isn't heavily soluble in AsCl3.

The other easier way I found several years ago was an in situ reaction that was based on a 17th century reaction by a German apothecary. it was in a chemical prep book writen either in the late 19th or early 20th century.


it involved combining an excess of sulfuric acid with sodium chloride and arsenic trioxide combined.

it's important to have an excess of H2SO4 to keep H2O sequestered.

This can be done in a retort. As you can imagine the AsCL3 will likely be contaminated with HCL. This isn't the easiest to rid of it seems.



woelen - 27-9-2022 at 03:52

Are you really considering doing this? In your recent posts I see a strange pattern, I see a particular interest in extremely toxic chemicals, and I have the impression that this interest is not purely theoretical :o

Discussion and experimenting at this level is not wrong in itself, but we absolutely do not want to read about someone killing himself, due to abuse of intensely toxic chemicals, generated in his own backyard. In the past we had a person, who killed himself in the process of making COCl2, despite being warned several times by other members.

6dthjd1 - 21-10-2022 at 12:33

Quote: Originally posted by woelen  
Are you really considering doing this? In your recent posts I see a strange pattern, I see a particular interest in extremely toxic chemicals, and I have the impression that this interest is not purely theoretical :o

Discussion and experimenting at this level is not wrong in itself, but we absolutely do not want to read about someone killing himself, due to abuse of intensely toxic chemicals, generated in his own backyard. In the past we had a person, who killed himself in the process of making COCl2, despite being warned several times by other members.




Considering Glauber did not die in making AsCl3 and that the chemical was made many times since then gives considerable weight to the idea that it's toxicity is not commensurate to chemcials like COCl2.



Texium - 21-10-2022 at 16:09

Quote: Originally posted by 6dthjd1  
Considering Glauber did not die in making AsCl3 and that the chemical was made many times since then gives considerable weight to the idea that it's toxicity is not commensurate to chemcials like COCl2.
Considering you are not Glauber, and are clearly inexperienced with chemistry in general, gives considerable weight to the idea that your rationalization is ill-founded.

Many people have made phosgene without dying too. Probably many more than those who have made arsenic trichloride, considering phosgene is far more useful. That doesn’t mean either compound is safe to make. Especially not the way you’re hoping to do it.

j_sum1 - 21-10-2022 at 16:25

Maybe I am getting old and cranky and more risk-averse. But there seems to be a proliferation of sub-sensible ideas at the moment.
There are some chemicals that are just serious and not to be trifled with. Phosgene is definitely one. Anything with arsenic is another.

Boffis - 22-10-2022 at 05:13

Back to the OP's question. I noticed recently something I had almost forgotten about. The old method of analysis for As3+ was to solvent extract the AsCl3 from strong hydrochloric acid, there is an optimal HCl concentration if I recall correctly. I will track the details down if anyone is interested. The arsenic was usually isolated as some insoluble compound but you could probably fractionally distil the solution to obtain the AsCl. I think that the direct chlorine route in say carbon tetrachloride or chloroform would give the best yield and quality. To some extent it depends on what you want to do with it.

By the way the reaction between AsCl3 and water to As2O3 and hydrochloric acid is reversible and therefore an equilibrium reaction.

6dthjd1 - 15-11-2022 at 05:22

Quote: Originally posted by Texium  
Quote: Originally posted by 6dthjd1  
Considering Glauber did not die in making AsCl3 and that the chemical was made many times since then gives considerable weight to the idea that it's toxicity is not commensurate to chemcials like COCl2.
Considering you are not Glauber, and are clearly inexperienced with chemistry in general, gives considerable weight to the idea that your rationalization is ill-founded.

Many people have made phosgene without dying too. Probably many more than those who have made arsenic trichloride, considering phosgene is far more useful. That doesn’t mean either compound is safe to make. Especially not the way you’re hoping to do it.



Glauber had good glassware. But Glauber did not have what we have.

Glauber used soda-lime glass. That glass shatters more easily than borosilicate.

Glauber used naked flames.


Glauber did not go outside. If he vented his venting is inferior to our methods of venting.

If you can read any latin you are welcome to refute me. (I can moderately)

woelen - 15-11-2022 at 07:57

Those were different times. Glauber did not know of carcinogenic properties of As-compounds. Het did not think of long-term effects. He was not killed, but what long-term effects did he suffer from. Many of these old-time scientists had illnesses, which we do not know of. Many illnesses were just accepted, they were part of life, and some people were lucky, and others were less lucky. There were no explanations, simply because of lack of knowledge.

Now we know better, we know the risks. Only if you can safely manage those risks you should do the experiments. It is your choice, and your assessment, but you do not give me the feeling that you really have a good idea of the risks. I myself have done a lot of experimenting and feel quite comfortable, working with e.g. Br2, Cl2, toxic metal salts and many more, but using and/or producing volatile As-compounds for me is one step too far, I value my health too much. I also accept the limitations of home science, I have no professional lab, although I have quite a few very nice chemicals and glassware.

A good amateur scientist is capable of going beyond the basic home experiments, but also knows his/her limitations!

B(a)P - 15-11-2022 at 11:45

Due to his poor practices Glauber was poisoned many times during his work. As a result he became seriously ill at the ripe old age of 56.