Evaporation of HCl ?

[Jees]

Several tec's use the property of HCl (muriatic acid) to evaporate when dried out.

1) 100 ml dist. water + 3 drops HCl (for analisis, Merck), pH was around 2.5, double boiler evaped, left a few hairs of dry rest, almost nothing.

Trowing 50 ml dist water on top, checking ph = next to 7
So we can say yes the HCl was evaped.


2) 100 ml dist. water + 3 drops HCl (for analisis, Merck), pH was around 2.5 again, now trow in 2 grams of rice flour and mix, double boiler evaped till all BONE dry, had to mortar and pestle the flakes to go back to powder.

Trowing 50 ml dist water on top, mixing, checking ph = next to 2.7 :shock:
So we can say the HCl was NOT fully evaped because of in this case presence of rice-flour.


Now this 2nd test is enough for me to question the HCl evap-tecs, no?
So I am confused about this HCl evap phenomena and it's implications if any.

 

[Mr.Peabody]

Most of the HCl evaporates off. I suspect what's left after the evap is likely stuck to whatever container it was held in, and is then released when you added water to it again. I'm no chemist, but that's my best guess.

The thing about using HCL is, as long as there are no harmful impurities, it's fairly safe. Obviously one wouldn't want to have a ton, but a little won't hurt. After all, it's the same acid in your stomach!

 

[Jees]

Thx.
It was not on the container for sure, I checked that.

 

[Poekus]

Be careful with evapping HCl in your oven. I fucked up a rust free steel one a couple of years back by doing this (it rusted ). Also if it's an electrical it can mess up your electronics.

 

[Jees]

Noted, thank you.

 

[Mr.Peabody]

Thx.
... but how do I know where the safe distinguishes from unsafe?

It really just depends on the amount you use in the first place. When using HCL in the defatting step of an extraction, I would then use NaOH to basify. These two are very good to use together, as the product of the two is harmless water and table salt (H20 and NaCl). So when you basify, you are actually removing any traces of the HCl and are left with just the base NaOH.

On the salting out step of an extraction, I also use HCL. This would cancel out any (supposedly, but not likely) NaOH that made its way into the NP solvent. Finally, the amount of HCL used is only about 5 drops or so per 150 ml of water. While I obviously wouldn't ingest these five drops straight (which would cause burns), diluted in my stomach these drops would be inconsequential.

Here's the math:

33% HCl (a common strength of HCl) is about 10 molar (this is mols/liter, a mole is an amount of molecules)


Lets say five drops is about 0.5 ml (which five drops is probably far less than this)

That means that .5 ml of 33% HCl has (10 mol/liter)*(.0005 liter)= 0.005 mols of HCl.


The stomach has on average a concentration of 0.16 molar. If there was as little as 150 ml of fluid in the stomach at this concentration, the stomach would already have (0.16 mol/liter)*(.15 liter) = 0.025 mols of HCl

So, adding in that 0.005 mols from the HCl, the final stomach concentration would be (0.005 mol + 0.025 mol)/(0.15 liter)= .2 molar

0.2 molar is only 25% more concentrated, and likely the stomach fluctuates this high or higher naturally.

It's not high enough to cause damage, and all one would need to do is take a tums!

These were all overly conservative guesses, and maybe not all of the HCL evaporates, a sizable portion does, you can smell it (do not recommend doing this much). So, HCl is relatively safe to work with.

 

[Jees]

Thanks for this practically perspective :thumb_up:

 

[Infundibulum]

2) 100 ml dist. water + 3 drops HCl (for analisis, Merck), pH was around 2.5 again, now trow in 2 grams of rice flour and mix, double boiler evaped till all BONE dry, had to mortar and pestle the flakes to go back to powder.

Trowing 50 ml dist water on top, mixing, checking ph = next to 2.7 :shock:
So we can say the HCl was NOT fully evaped because of in this case presence of rice-flour

That would be one interpretation. Another interpretation would be that your HCl solution changed the rice flour in a way that it now behaves as an acid.

But generally, the missing measurements here are:

1. pH of water just with the rice flower
2. the pH of your HCl solution after the addition of the rice flour.

Also this:

Trowing 50 ml dist water on top, checking ph = next to 7
So we can say yes the HCl was evaped.

The pH you checked is 7? don't you find that odd? What is the pH of your distilled water, before the addition of any acid? Most often distilled water is not at pH=7, because it readily absorbs CO2 from the atmosphere which dissolves as carbonic acid. the pH of distilled water is closer to 4-5 than 7.

Overall, you got quite a few methodological errors in your experiments and I really applaud the initiative (as well as the thinking behind them)! Still though they do not tell us much.

 

[Jees]

Lets say five drops is about 0.5 ml (which five drops is probably far less than this)

I checked and came out at around 0.9 - 1 ml for 5 drops of my bottle.

* * *

...Methodological errors...

it was not supposed a scientific paper, just a determination of rough pH levels and I welcome someone proving my resume-findings to be wrong by use of professional equipment and without methodological errors. That would be an eye opener for me.

...What is the pH of your distilled water, before the addition of any acid?...

okay, I should have said it was demineralized water which can have another pH range (6 - 7.5) at delivery depending on how well the process was executed in the ion exchange resin beds, seems nothing in big industry is ideal. Checked it seemed 5.9 for this particular jar .

...interpretation...HCl solution changed the rice flour...behaves as an acid.

possible, but in the thread I posted likewise experiment with mimo and gave same outcome, so it was actually a double outcome in same direction.

* * *

I applaud the aspiration of this site to yearn scientifical correctness, and where not possible to make at least notion of it. For that sake I remade the experiment:

* with a calibrated pH pen (it was not in first because I was looking for rough pH levels and pH-change);
* giving the pH reading much more time to stabilize;
* taking important inbetween pH reading;
* using more HCl to magnify it's appeareance.

* * *

1) 100 ml demi-water (pH 5.9) plus 5 drops HCl made ph = 2.15.
After evaping in double boiler, adding 50 ml water, stirr, pH = 6.4
I have no idea or explanation for this 0.5 pH rise.

2) 100 ml demi-water (pH 5.9) plus 5 drops HCl made again pH = 2.15
Adding rise flour, let it soak for 1 hour, pH unchanged at 2.15 <-- important
After evaping in double boiler, grounding the flakes, adding 50 ml of same demi-water, stirr, pH = 2.00
Adding another 50 ml of same demi-water, pH = 2.20 :shock:

* * *

...Still though they do not tell us much...

Depend on what one finds worth knowing, but enough and important for me to realize that it is a false idea that when one evaps HCl on a substrate, it is gone. Enough for me to debunk this "belief".
Therefore to be bound to what Mr.Peabody said, to monitor wisely the added amount in the first place as the measure for safety, and not relying on the evap-belief for the sake of that.

Using the stated amounts of HCl in the tecs would not lead to injury or this must have shown long time before. So my "being wary" for HCl might have been a non-concern, but still I find it nice to just realize that evaping HCl carrying substrates do NOT become miraculous non-acid by the act.
Only that.
.

 

[Infundibulum]

Thanks for looking further into it!

Depend on what one finds worth knowing, but enough and important for me to realize that it is a false idea that when one evaps HCl on a substrate, it is gone. Enough for me to debunk this "belief".
Therefore to be bound to what Mr.Peabody said, to monitor wisely the added amount in the first place as the measure for safety, and not relying on the evap-belief for the sake of that.

The only problem with this is that HCl is a gas and it does evap cleanly, as you have previously demonstrated. And to state here that in the presence of another material (i.e. rice flour in your case) HCl stays back contradicts what we generally know about HCl, that's why you should bring more rigorous support to your assertion...

My one concern that has not been addressed is that in the presence of acid and heat, rice flour changes to something that now behaves like an acid. This latter remark unfortunately makes sense biochemically and could very well explain your observations... Pretty much all I am saying here is that in your experiments you assumed that your final acidity (after rehydrating the rice flour) is coming from HCl, but you really do not know that. On the contrary, take a look at this excerpt:

2) 100 ml demi-water (pH 5.9) plus 5 drops HCl made again pH = 2.15
Adding rise flour, let it soak for 1 hour, pH unchanged at 2.15 <-- important
After evaping in double boiler, grounding the flakes, adding 50 ml of same demi-water, stirr, pH = 2.00
Adding another 50 ml of same demi-water, pH = 2.20 Shocked

As you remark, isn't it weird that your final pH measurement is 2.20? This means that (assuming that is coming from residual HCl and that your rice flour is indeed an inert material), pretty much nothing of the HCl evaporated in the presence of rice flour! I find it an extraordinary claim indeed!

I think you might need to repeat your experiment, maybe a more inert biochemically material like gluten-free flour? sodium chloride? styrofoam pellets? pieces of paper? cotton? so that you get a feeling of how your observations on rice and HCl reflect in other systems.

 

[Jees]

...So I am confused about this HCl evap phenomena...

Still floating in that boat, thanks for motivating me to do more tests with various stuff, to be continued...

 

[Jees]

Low priority so this drips in slow.

Test with kitchen salt:

100 ml demin-H2O (pH 6.12) + 5 gr NaCL = pH 6.74
add 5 drops HCL = pH 1.87

total evaporation

add 100 ml demin-H2O (pH of this water was now 6.35, so the pen drifts a bit)
and dissolve all the salt = pH 3.14

I refrain to say it was surviving HCL, just see an acid effect remaining.
Next test will be done with little lab boiling stones, that's quite inert enough I guess.

 

[Infundibulum]

Low priority so this drips in slow.

Test with kitchen salt:

100 ml demin-H2O (pH 6.12) + 5 gr NaCL = pH 6.74
add 5 drops HCL = pH 1.87

total evaporation

add 100 ml demin-H2O (pH of this water was now 6.35, so the pen drifts a bit)
and dissolve all the salt = pH 3.14

I refrain to say it was surviving HCL, just see an acid effect remaining.
Next test will be done with little lab boiling stones, that's quite inert enough I guess.

:shock:

That is indeed quite confusing. I am amped to see more tests!

 

[Mr.Peabody]

So, how about just adding the HCl to nothing but a glass dish, letting it evaporate, and then adding the same amount of distilled water (that had been tested for pH before hand) and seeing if there is a noticeable change in acidity?

Also, the point of using HCl is to attract the alkaloids (basic substances). So, if there was no evaporation of HCl, one could still assume at least some neutralization from the presence of the alkaloid content.

My last idea,
When I use HCl to pull mescaline, I often dry off the water in a large pyrex dish in my oven, set at it's lowest temperature. Perhaps the presence of heat as a drying aid (which is common) would further help to drive off any excess HCl.

My thought is that because the HCl is being dried from various substances, perhaps it takes much longer for it all to evaporate. In the case of the rice, it may be stuck in the pores of the rice, and absorbed in to it, only to be released when rehydrated. For the table salt, perhaps the ionic nature of the salt interacted with the HCl, which would also ionize, thus keeping a certain amount behind and not evaporating.

This is pretty fun! We need to get to the bottom of this! When I get more time, if this is not solved by then, I'll do some tests of my own.

 

[Jees]

...My thought is that because the HCl is being dried from various substances, perhaps it takes much longer for it all to evaporate...

Have been sort of my thoughts too, that ideally DRY is quite impossible when there is still humidity in the air. Any tiny bit of non-100%-dry could perhaps still carry acid. Perhaps I think stuff is dry, looks dry, and still not 100%. Just guessing.

Pic is my evap setup, a pot with simmering water, a little pan on top as a lid, in that pan a teflon (in my eyes inert, yes, no?) anti sticking baking foil. I have not tried other setups so far, so possible systematic error(s) are not eliminated. Few tests done by others might help.

 

[Infundibulum]

Why don't you just try evaporating it in a pyrex dish, in the oven? glass and dry heat is guaranteed to make your system inherently inert and you also get to evaporate all the moisture.

 

[The Traveler]

Why don't you just try evaporating it in a pyrex dish, in the oven? glass and dry heat is guaranteed to make your system inherently inert and you also get to evaporate all the moisture.

I would not do that in an oven since Hcl is very corrosive and will even rust stainless steel within the blink of an eye.

So in effect evapping Hcl in an oven is a good way to quickly ruin that oven.


Kind regards,

The Traveler

 

[Jees]

It was setup like used for real purposes which was initially my only concern.
To re-find logic by deduction, indeed different methods must and will be sued, slowly, also making more dudes extremely welcome to confirm/object my results.

 

[Jagube]

Test with kitchen salt:

100 ml demin-H2O (pH 6.12) + 5 gr NaCL = pH 6.74
add 5 drops HCL = pH 1.87

total evaporation

add 100 ml demin-H2O (pH of this water was now 6.35, so the pen drifts a bit)
and dissolve all the salt = pH 3.14

Maybe some HCl got trapped in the NaCl crystals as they formed?

Did you try repeating the same test on the pH 3.14 salt solution? If there was HCl trapped in the salt crystals, after repeating the test the pH should have increased further.

 

[Jees]

Sorry Jugabe, I remember that I powdered glass boiling stones (lab stuff) to repeat the experiment with, but I never did it actually. I suppose it was available time management making me drop the issue. An unfinished story