Sciencemadness Discussion Board - Preparation of Al(HSO4)3

Preparation of Al(HSO4)3

EvlRenne - 15-11-2018 at 13:56

Hello everyone,

guys, I've been searching on web, and can't find how can I make aluminum hydrogen sulfate? I want to try it as a catalyst for organic synthesis as a lot of reference says about its efficiency.

[Edited on 15-11-2018 by EvlRenne]

Metacelsus - 16-11-2018 at 01:15

You could try mixing aluminum sulfate (Al2(SO4)3) with sulfuric acid.

EvlRenne - 16-11-2018 at 04:03

Quote: Originally posted by Metacelsus

You could try mixing aluminum sulfate (Al2(SO4)3) with sulfuric acid.

And evaporate at 200+ C? I tried, did not work.
Only 1 mention I found from one of the article:
Preparation of aluminum hydrogen sulfate
Anhydrous aluminum chloride (33.4 g, 0.25 mol) was placed into a 500 mL suction flask equipped with a constant-pressure dropping funnel. The gas outlet was connected to a vacuum system through an adsorbing solution (water) and an alkali trap. Concentrated sulfuric acid (98%, 73.5 g, 0.75 mol) was added drop-wise over a period of 1 h at room temperature during which HCl was evolved. After completion of the addition, the mixture was stirred for 30 min, while the residual HCl was eliminated by suction. Finally, a pale-brown solid material was obtained (77.0 g).

I will not be able to do it, because I have no equipment to prepare AlCl3.
I hope that there is the other way to make it.

clearly_not_atara - 16-11-2018 at 12:18

I think the "simplest" version is to add aluminium metal to concentrated sulfuric acid... obviously this will cause a very vigorous reaction, but it obviates the need to dry the product. I'm not sure how to contain the reaction -- even adding small pieces of aluminium to an excess of H2SO4 rapidly stirred on an oil bath is likely to be too vigorous. It might be possible to dilute the sulfuric acid with a sufficiently inert solvent - the only thing that comes to mind are fluorinated solvents, maybe PCBTF.

EDIT: above is wrong, Al will reduce H2SO4 to SO2

Another possibility is to replace aluminium chloride with another salt which is easier to dry and where the conjugate acid can be distilled off easily. One interesting possibility is aluminium borate, AlBO3, which would react like this:

AlBO3 + 3 H2SO4 >> H3BO3 + Al(HSO4)3

Boric acid will not vaporize at normal pressures but it can be vacuum distilled and IIRC it is significantly more volatile than sulfuric acid.

Quote:

And evaporate at 200+ C? I tried, did not work.

Can you describe what happened? Did you get a lot of SO2 release?

[Edited on 16-11-2018 by clearly_not_atara]

Jackson - 16-11-2018 at 12:23

Just get a big stainless steel trashcan(if stainless steel doesnt react with sulfuric acid of course) put some sulfuric acid at the bottom and dump some aluminum into it, then run.

clearly_not_atara - 16-11-2018 at 12:30

See my edit above: Al will reduce conc. H2SO4, which makes the procedure inapplicable.

It would be nice to find another volatile acid which is not dehydrated or oxidized by H2SO4. Aluminium triacetate might be obtained by dissolving aluminium metal in anhydrous acetic acid, although the reaction might need a catalyst to get started. Then you could add Al(OAc)3 to H2SO4 and distill off AcOH. We know H2SO4 won't dehydrate AcOH.

EvlRenne - 16-11-2018 at 14:14

Quote: Originally posted by clearly_not_atara

Quote:

And evaporate at 200+ C? I tried, did not work.

Can you describe what happened? Did you get a lot of SO2 release?

[Edited on 16-11-2018 by clearly_not_atara]

It was a lot of Al2(SO4)3 as white crystals, SO2 was in moderate amount.

kmno4 - 16-11-2018 at 15:51

Quote:

It was a lot of Al2(SO4)3 as white crystals, SO2 was in moderate amount.

No wonder:

al.bmp - 67kB

Al(HSO4)3 exists only in Iranian, Indian... etc "publications" and its existence has nothing to do with reality.
Procedure (and results) for its preparation, given above (J. Chem. Sci. Vol. 128, No. 3, March 2016, pp. 429–439. by Iranian team) , is copied from earlier article (Bull. Chem. Soc. Jpn., 76, 1863–1864 (2003), by another Iranian team).

ps.

"Finally, a pale-brown solid material was obtained in 77
g. Al(HSO4)3 was characterized by the determination of its H+
content by titration with NaOH (Calcd 0.95%, Found 0.96%)
and SO4 by..... "
I wonder, how they obtained this result by simple HaOH titration ??
And 73,5 g of 98% H2SO4 is not 0.75 mol but 0,735 mol.

clearly_not_atara - 16-11-2018 at 21:18

I'm surprised that the Bulletin of the Chemical Society of Japan could be so deceived. I would have hoped that the peer reviewers would object to the paper's use of a nonexistent compound!

EvlRenne - 17-11-2018 at 10:29

Thank you all for answers, now I'm a little bit confused, what are they use then instead of Al(HSO4)3?
https://link.springer.com/article/10.1007%2Fs00706-003-0083-...
https://link.springer.com/article/10.1007%2Fs12039-016-1036-...
https://link.springer.com/article/10.1134%2FS107036321505030...
https://link.springer.com/article/10.1134%2FS107036321606028...

[Edited on 17-11-2018 by EvlRenne]

kmno4 - 18-11-2018 at 14:19

Iran, Iran, Iran and Iran

What is the catalyst ?
Who knows.... Reaction of AlCl3 and H2SO4 should be more investigated, with elemental analysis of the product.
It cannot be Al(HSO4)3 because it woud split into normal sulfate and H2SO4.
The procedure (and result) for "Al(HSO4)3" preparation is identical (with scaling) in each cited article - it is highly doubtful whether these articles have any scientific value.
Maybe islamic chemistry is different

الله أكبر

Melgar - 18-11-2018 at 18:27

Quote: Originally posted by kmno4

Maybe islamic chemistry is different

الله أكبر

Despite all the weird languages that spambots speak in, I think you may actually be the first to use Arabic script here. I see you are a human. Carry on.

Though, in Iran, I suppose it would actually be Farsi. But for the purposes of this discussion, it makes no difference.

Gearhead_Shem_Tov - 18-11-2018 at 21:06

Quote: Originally posted by kmno4

Iran, Iran, Iran and Iran

...
Maybe islamic chemistry is different

الله أكبر

A: "What have Islamic chemists ever given us!"

B: "Mineral acids?"

A: "What?"

B: "Strong mineral acid."

A: "Oh, yeah, yeah, they did give us that. That's true."

C: "And alcohol distillation."

D: "Oh, yeah, distillation. Remember, Reg, what drinks used to be like?"

A: "Yeah, alright, I'll grant you, mineral acids and alcohol are two things the Islamic chemists have done."

E: "And the alkalis."

A: "Yeah, well, obviously the alkalis. I mean, the alkalis go without saying, don't they? But apart from mineral acids, alcohol, and alkalis—"

B: "Alembics?"

C: "Aludels?"

D: "Athanors?"

B: "Water baths."

C: "Sand baths."

A: "Right, yeah, well, apart from ..."

[Edited on 19-11-2018 by Gearhead_Shem_Tov]

EvlRenne - 19-11-2018 at 03:41

Okey, guys, all jokes aside.
So that kind of catalyst isn't exists?
How come Russian/Japanese/German/Iranian/Chinees (https://www.sciencedirect.com/science/article/pii/S100184170...)/Brazilin (http://www.scielo.br/scielo.php?script=sci_arttext&pid=S...) chemistry journals mentioned it?
All of it have no value?

[Edited on 19-11-2018 by EvlRenne]

[Edited on 19-11-2018 by EvlRenne]

kmno4 - 19-11-2018 at 07:12

Quote: Originally posted by EvlRenne

How come Russian/Japanese/German/Iranian/Chinees (https://www.sciencedirect.com/science/article/pii/S100184170...)/Brazilin (http://www.scielo.br/scielo.php?script=sci_arttext&pid=S...) chemistry journals mentioned it?
All of it have no value?

These articles also are produced by.... Iranian teams.
Journal name is just only a name. Some journals are more reliable, other journals are not. I have seen too many fake procedures and sentences "we were unable to obtain any reliable results following procedure given by (name) in (journal)". When I see "simple, efficient, microwaves, solvent-free.....etc " it means that it may not work at all. Sometime is very clear (as in Al(HSO4)3 case) that it must be something wrong.
But - I do not say it does not work at all.
I say that it cannot be Al(HSO4)3. Besides, it is described as "non hygroscopic". Do you know any non-hygroscopic Al salt, with simple, not chelating anion ? I do not know such one.
So - what it is ? Something highly acidic, that is all I can deduce from these articles. I heard about sulfonated alumina (by chlorolufonic acid), but if it has something to do with it - I do not know.
As they say - experiment is king

clearly_not_atara - 19-11-2018 at 09:53

Is it possible that the rxn product of H2SO4 + AlCl3 is a useful catalyst? Sure. But is it "non-hygroscopic"? I can't believe that!

"Anhydrous aluminum chloride (3.34 g, 0.025 mol) was charged in the flask and concentrated sulfuric acid (98%, 7.35 g, 0.075 mol) was added dropwise over a period of 30 min at room temperature. HCl evolved immediately. After completion of the addition, the mixture was shaken for 30 min, while the residual HCl was eliminated by suction. Finally, a pale-brown solid material was obtained in 7.7 g."

NB. gas not characterized; weight not consistent with Al(HSO4)3; product not subject to elemental analysis. We expect 8 grams of aluminium bisulfate, we find 7.7. What else was lost? Water? From concentrated sulfuric acid under mere suction? Sure, you say, mechanical losses.

I have a question: why do the mechanical losses stay exactly the same when you make the system ten times larger? From EvilRenne's post, above:

"Anhydrous aluminum chloride (33.4 g, 0.25 mol) was placed into a 500 mL suction flask equipped with a constant-pressure dropping funnel. The gas outlet was connected to a vacuum system through an adsorbing solution (water) and an alkali trap. Concentrated sulfuric acid (98%, 73.5 g, 0.75 mol) was added drop-wise over a period of 1 h at room temperature during which HCl was evolved. After completion of the addition, the mixture was stirred for 30 min, while the residual HCl was eliminated by suction. Finally, a pale-brown solid material was obtained (77.0 g)"

That's right: precisely the same relative masses, within 1% error (i.e. amazing), just scaled up by a factor of ten. There are two possibilities:

- some mysterious aluminium-chloride-sulfate compound prepared with exquisite precision

- fakery and plagiarism

Guess what I'm betting on?

chornedsnorkack - 20-11-2018 at 12:21

This:
https://pubs.acs.org/doi/abs/10.1021/ja01172a002
lists a solid phase "Al2(SO4)3.3H2SO4.12H2O", which would rearrange as "Al(HSO4)3.6H2O"

kmno4 - 23-11-2018 at 02:24

I have seen this paper already.

Quote:

"Al2(SO4)3.3H2SO4.12H2O", which would rearrange as "Al(HSO4)3.6H2O"

Rearranging chemical symbols on paper/editor is rather poor kind of chemistry.
Why not H3[Al(SO4)3]•6H2O, Al2(SO4)(HSO4)4•H2SO4•12H2O, or whatever ?
Because exact molecular structure of this compound is not known, such a "rearrangement" is pure speculation.

In mentioned paper, there is a reference (from Monatshefte für Chemie) about similar compounds ,2Al(HSO4)3•7H2O , as suggested by author it is a complex, with aluminosulfate anion. There is also given preparation of it, from conc. H2SO4 and aluminium sulfate (but it is not clear, at least for me).

The last publication about Al2(SO4)3-H2SO4-H2O system, is article from the Journal of Chemical Society (DOI: 10.1039/JR9520004431). They use much more sophisticated methods of analysis than given in earlier publications. The compound Al2(SO4)3•3H2SO4•12H2O is NOT detected in their experiments and - according to the authors - it is possibly Al2(S04)3•H2S04•8H20. They also report several other acid sulfates.
The paper is worth reading but.... date of its publication is 1952 year. So, the system Al2(SO4)3-H2SO4-H2O awaits for modern reinvestigation.
Anyway, there is no (so far) reported anhydrous acid aluminium sulfates.

EverythingAl2O3 - 18-8-2021 at 20:11

Sorry to awaken an old thread no one cared about but I have come across a reaction that mentions using Al(HSO4)3 for preparing thioacetals which led me to this thread and I went down a spiral of digging. In their materials and methods it says "All reagents were purchased from Merck and Aldrich and used without further purification." but from my googling I can find no Merck Chemical Company as a stand alone entity (only a medical/biotech company was found). Merck and Aldrich just pulls up Sigma Aldrich which does not recognize this chemical name. It makes me wonder if this is just some
Al2(SO4)4 XH20 salt. I found a similar paper for Fe(HSO4)3. I'm not sure if this is similar because I cannot find this salt in any referenced chemical supplier "Chemicals were either prepared in our laboratories or purchased from Merck, Fluka and Aldrich Chemical Companies." Again only found Fe2(SO4)3 XH2O. I'd say if all these papers referenced are not frauds, they are using a strange synonym common to Iran but nowhere else seeing as so many different authors use the same ones and all authors in the papers referenced in this thread are from about 5 different Iranian universities. I have contacted one author through research gate about the preparation of Fe(HSO4)3 or potential synonyms. Will update if they respond.

Triflic Acid - 19-8-2021 at 05:57

Reading this, I can come to only one conclusion. Aluminum bisulfate is an Iranian conspiracy designed to destroy the experiments of American scientists(Death to America!).

Well, contacting the writer is always a good first step. It might be that the papers were initially written in Arabic, peer reviewed in Arabic, and then translated right before publication. There, sulfate may become bisulfate. Or it might be just an abbreviation that is more common in that country to mean a suspension of the respective metal sulfate in sulfuric acid. Will be interesting to see what the author says.

woelen - 22-8-2021 at 23:15

Another thing which would trigger suspicion for me is the color they mention. The compound is described as being brown. Aluminium ion and sulfate and bisulfate all are colorless and all other pure Al-salts are white (or the color of the anion). So, a salt, containing bisulfate ion (if such a thing exists) almost certainly would be white. Also a non-stoichiometrically ill-defined mixed salt, containing sulfate ion and bisulfate ion would be white (such a thing may be more likely to exist).

EverythingAl2O3 - 29-9-2021 at 16:48

Author directed me to this paper that mentions the preparation of Fe(HSO4)3 and might be the same for Al(HSO4)3
A 500 mL suction flask was equipped with a constant-pressure dropping funnel. A gas outlet was connected
to a vacuum system through an absorbing solution (water)
and an alkali trap. Anhydrous FeCl3 (0.25 mol) was charged
into the flask and concentrated sulfuric acid (98%, 73.5 g,
0.75 mol) was added dropwise over a period of 30 min at
room temperature. HCl gas was evolved immediately. After completion of the addition of the H2SO4, the mixture
was shaken for 30 min.; meanwhile, the residual HCl was
exhausted by suction. A pale brown solid material was thus
obtained.

Attachment: Fe(HSO4)3 preparation.pdf (436kB)
This file has been downloaded 263 times

EverythingAl2O3 - 1-10-2021 at 14:29

I found the procedure for Al(HSO4)3. It is the same.
A 50 mL suction flask was equipped with a constant-pressure dropping funnel. The gas outlet was connected to a vacuum system through an adsorbing solution (water) and an alkali trap. Anhydrous aluminum chloride (3.34 g, 0.025 mol) was charged in the flask and concentrated sulfuric acid (98%, 7.35 g, 0.075 mol) was added dropwise over a period of 30 min at room temperature. HCl evolved immediately. After completion of the addition, the mixture was shaken for 30 min, while the residual HCl was eliminated by suction. Finally, a pale-brown solid material was obtained in 7.7 g. Al(HSO4)3 was characterized according to the previously reported procedure. Al(HSO4)3 preparation I believe the pale brown color which is mentioned is due to the fact that AlCl3 commonly has iron impurities which would contribute to the abnormal coloration of an aluminum salt.
Though I find it hard to believe that Al(HSO4)3 was made with this. There is no reason that this would not just react to Al2(SO4)3 especially since Al(HSO4)3 is not commercially available and only chemists from Iran mention its existence.

[Edited on 1-10-2021 by EverythingAl2O3]

Amos - 2-10-2021 at 10:05

Quote: Originally posted by EvlRenne

Anhydrous aluminum chloride (33.4 g, 0.25 mol) was placed into a 500 mL suction flask equipped with a constant-pressure dropping funnel. The gas outlet was connected to a vacuum system through an adsorbing solution (water) and an alkali trap. Concentrated sulfuric acid (98%, 73.5 g, 0.75 mol) was added drop-wise over a period of 1 h at room temperature during which HCl was evolved. After completion of the addition, the mixture was stirred for 30 min, while the residual HCl was eliminated by suction. Finally, a pale-brown solid material was obtained (77.0 g).

So even if these papers are free of fraud and they correctly described the formula of their catalyst, if the material you are looking for is traditionally derived from anhydrous aluminium chloride, you will likely not be able to make it via aqueous chemistry. These transition metal lewis acid catalysts such as FeCl3, AlBr3, etc are covalent and have different structures than the ionic salts derived from aqueous chemistry. Acetalization is a very well-studied process and has been done with a wide variety of different catalysts, many of which are simple to obtain such as p-TsOH. In my opinion it's better to use something that has repeatedly been documented as working. I hope this helps.

EverythingAl2O3 - 6-10-2021 at 18:06

Quote:

This was less me trying to find a use for it and more about unraveling the mystery of what the heck it is and how to make it.