Concentration of hydrochloric acid for acid-base extraction

[RedHat]

I was reading over this tutorial that covers acid-base extraction of H #3, and it details the use of 28% concentrated hydrochloric acid, and I was wondering.. Does anyone know if theres a reason that you cant use a higher % of the HCl? Or does it need to be exactly 28%? Would a 36% to 38% mix not yield the same results?

 

[Jekyl Anhydride]

If you noticed in the article it said:

FYI, hydrochloric acid can be purchased in gallon jugs at hardware stores under the name Muriatic acid, 28%.

Muriatic acid is cheap and widely available. I prefer ACS lab grade myself but if you can work out the stoichiometry/ math or titrate properly then any percentage is fine. Just have a very tiny pipette for the fuming highly concentrated stuff if 28% isn't your thing.

 

[RedHat]

If you noticed in the article it said:

FYI, hydrochloric acid can be purchased in gallon jugs at hardware stores under the name Muriatic acid, 28%.

Muriatic acid is cheap and widely available...

Thanks for the reply. And I did see that line about Muriatic acid, and even though all the similar articles specify to use 28% concentrated HCl, none of them specify why it needs to be 28%, leading one to believe that maybe the 28% was specified simply because thats the concentration that Muriatic acid comes in, as opposed to it being specified because the acid-base extraction process requires exactly that concentration, and not a higher concentration (such as 36% to 38%)

... I prefer ACS lab grade myself ...

As do I.

 

[RedHat]

Whew, I'm glad I decided to search these forums a little bit more. I found this thread created by the user abcdefgh123, in which his problem ended up being his use of 35% concentrated HCl, instead of 28%.

 

[Jekyl Anhydride]

That was because his math was off, the right quantity of 35% will work just fine. If it calls for 4-5 drops of muriatic and you use 4-5 drops of 35%, of course it's going to take a ton of carbonate to neutralize. At that point he would have been better off with NaOH.
Actually it said:

Now mix up a solution of 5ml 28% hydrochloric acid and 5ml distilled water

If he would have done the math it should have been like 3.9ml of HCl, not 5ml of 35%. Thank god it wasn't something like a birch reduction or he might have blown himself up.

 

[RedHat]

That was because his math was off, the right quantity of 35% will work just fine. If it calls for 4-5 drops of muriatic and you use 4-5 drops of 35%, of course it's going to take a ton of carbonate to neutralize. At that point he would have been better off with NaOH.
Actually it said:


If he would have done the math it should have been like 3.9ml of HCl, not 5ml of 35%. Thank god it wasn't something like a birch reduction or he might have blown himself up.

Mind explaining how you got to 3.9ml of HCl? (Im sure thats a noob question, but I'm a programmer, not a chemist)
If I just kept an eye on the pH level, would the concentration of HCl being added really matter that much?

 

[Jekyl Anhydride]

That was just my poor math on the fly, but what I meant was that if it called for 5ml of 28% muriatic/ HCl ,then somewhere around 3.9ml of 35% HCl should be in the same ballpark. If you were making a drink with exactly 0.4oz of EtOH and you had a bottle of 80 proof and a bottle of 151 proof, you would use approx 1/2 a shot of 151 or a full shot of 80 and end up at the same place.

Same holds true for pH and other titrations, if the stoichiometry is known then it's foolproof. Not sure why this is so frustrating to me, it's not you, I guess it's just been a long day at work. Apologies if I came across as hostile.

To answer your question though:
Yes, if you have a quick read pH pen or take your time with papers/ reagents then the acid concentration shouldn't matter. When some of these recipes call for the water in muriatic to thoroughly wet the sample then it's more problematic I suppose.

 

[RedHat]

That was just my poor math on the fly, but what I meant was that if it called for 5ml of 28% muriatic/ HCl ,then somewhere around 3.9ml of 35% HCl should be in the same ballpark. If you were making a drink with exactly 0.4oz of EtOH and you had a bottle of 80 proof and a bottle of 151 proof, you would use approx 1/2 a shot of 151 or a full shot of 80 and end up at the same place.

I figured this is what you meant, but I wanted to confirm.

Not sure why this is so frustrating to me, it's not you, I guess it's just been a long day at work. Apologies if I came across as hostile.

I know the feeling. But no worries, I've got some thick skin.

I ordered a pH meter from Amazon, so I can do some "experimenting" and keep track of the pH levels.

 

[Jekyl Anhydride]

Thanks RH. Report back on how it goes and if you have any issues with the #3 sticking to the sensor bulb on the pH meter before it fully dissolves into a salt. I've heard a couple people mention this though I don't imagine it's a problem once a good portion of the H dissolves.

 

[RandomClean3]

Multiply 0,28 times the density and divide by the molar mass of HCl, that will tell you the molarity (moles per liter). Apply -log to that number and you'll get the pH. However the tutorial isn't very precise, a lot of eyeballing so ...eyeball it. I disagree with leaving the salt in the final product, it may be hiding impurities and inyecting salt??? No thanks. I would recomend dissolving the product in ethanol, a generous amount, about 10 times the mass of your product, and some more, you'll know you're done when the salt is in the bottom, then filter and let it dry. Heroin is about 1 in 12 soluble in ethanol, salt is less than 1 in 200.

PS: Sorry if it's all nonsense, I took way too much tapentadol and clonazepam and I'm nodding off.

 

[Jekyl Anhydride]

^ That sounds much more Merck Index approved, but by salt I was referring to Heroin Hydrochloride vs the freebase or buffering with NaHCO3 after say going to far in the acidic range and ending up with actual NaCL as a byproduct. There's also other options like the citrate, the tartrate, crashing it out of acetone, dichloromethane/water/acid and a separatory funnel or the classical method that avoids water altogether to prevent partial conversion back to morphine as per Le_Chatelier's_principle which states that acetylation is a reversible reaction and water will hydrolyze H in a time /temperature dependent manner where as an acetic acid solution will keep it acetylated far longer.

Conversion of heroin base to heroin hydrochloride:

For each kilogram of heroin base (or re-crystallized heroin base), 6.6 liters of of ethyl alcohol, 6.6 liters of ether, and 225 milliliters of concentrated hydrochloric acid are measured out. The base is dissolved by heating with one-third of the alcohol and one half of the acid. Another one-third of the acid is stirred in. Next, the remaining acid is added slowly, dropwise, until the product is completely converted to the hydrochloride salt. This result may be confirmed either by observing that a drop of solution evaporates on a glass plate leaving no cloudy residue or by placing a drop of solution on Congo red paper, observing it turn the paper blue. Once the conversion is complete, the remaining alcohol is stirred in. Then half of the ether is added, and the mixture is allowed to stand for 15 minutes. As soon as crystals begin to form in the solution, the remaining ether is added at once, stirred, and the the vessel is covered. The mixture becomes nearly solid after an hour. It is then filtered, and the solids are collected on clean filter paper. Wrapped in the paper, the solid is dried on a wooden tray, usually over lime rock, and dried in the sun. The fully dried product, heroin hydrochloride, is a fine white powder, ready for packing and shipping.

Obviously this was written up for the big boys converting quite a bit at once. But again math can save the day. For small amounts in a hobbyist fashion a quick conversion with water and HCl should do nicely. Just presenting the alternatives as some food for thought.

 

[RedHat]

Thanks RH. Report back on how it goes and if you have any issues with the #3 sticking to the sensor bulb on the pH meter before it fully dissolves into a salt. I've heard a couple people mention this though I don't imagine it's a problem once a good portion of the H dissolves.

Will do. This is the meter that I purchased. Then just to be able to compare it to something, I also purchased this pH test paper dispenser. I think the wide range should work fine (as opposed to a set of dispensers that only test the short ranges)

I disagree with leaving the salt in the final product, it may be hiding impurities and inyecting salt??? No thanks. I would recomend dissolving the product in ethanol, a generous amount, about 10 times the mass of your product, and some more, you'll know you're done when the salt is in the bottom, then filter and let it dry. Heroin is about 1 in 12 soluble in ethanol, salt is less than 1 in 200.

I totally agree about injecting salt... That just seemed silly to me, and potentially painful if you were to miss (at least I would think so, maybe im wrong). Would you recommend this method instead? It suggests monitoring the pH levels instead of just eye-balling it (which I was going to monitor anyways, but using the other method). That article is pretty similar to this one, except that it's a little more percise and uses different substances, but both use some form of acid-base extraction.