Sciencemadness Discussion Board - prep of HCl in isoOH?

prep of HCl in isoOH?

zig - 19-2-2014 at 22:46

I'm going to dissolve 37% HCL in 99% isopropyl alcohol, the resulting acidic isoOH will be dried with MgSO4 and used to crystallise a basic organic as the salt. (Conditions must be anhydrous).

What's the highest possible molarity of HCl in isoOH? Is this a good method of xtal precipitation, as opposed to treatment of the freebase with HCL gas? The former seems advantageous in that the amount of HCL to be used can be exactly calculated and prepared, eliminating the both the risk of over gassing and (the simply delightful) HCL gas exposure.

[Edited on 20-2-2014 by zig]

Oscilllator - 19-2-2014 at 23:22

1: What on earth is an xtal?
2: That wont work. MgSO4 only really works for drying small amounts of water, way less than what will result from mixing 37% HCl and isopropyl alcohol.
3: Correct me is I'm wrong, but this smells of cookery. Please dispel this notion by telling us precisely what you are trying to do.

DraconicAcid - 19-2-2014 at 23:33

Quote: Originally posted by Oscilllator

1: What on earth is an xtal?

Shorthand for crystal, in the same way that xmas is short for Christmas.

zig - 20-2-2014 at 01:56

Quote: Originally posted by Oscilllator

Correct me if I'm wrong, but this smells of cookery. Please dispel this notion by telling us precisely what you are trying to do.

Smells of cookery, huh? What part of my post offended your electronic nostrils? I posted in general terms because I'm after general information regarding amine salts, NOT just the world's best method of salting out a specific amine. (I happen to be working with phenethylamine, since ya asked)

Nonetheless I appreciate your response. Since MgSO4 is off the table due to it's hydration capacity, might Na2CO3 work better?

I guess another option less reliant on drying agents would be: bubble HCL gas through a large quantity of anhydrous isoOH to saturation, MgSO4 to remove any traces of H20 from HCL generator, and use acidic solution as needed. Still I'm curious as to what the HCL conc. in saturated isoOH would be.

[Edited on 20-2-2014 by zig]

Oscilllator - 20-2-2014 at 03:00

Uh, drying an acid solution with Na2CO3? Either I'm not understanding what you mean or that is a really dumb suggestion.
Bubbling HCl through an isopropanol solution is a much better way of getting it saturated, but if you are going to use it to crystallise an organic salt and you are going to be working with gaseous HCl anyway, why not just use the HCl gas directly?
As for the actual solubility data of HCl in isopropanol, I'm afraid I cant help.

zig - 20-2-2014 at 04:07

Quote: Originally posted by Oscilllator

Uh, drying an acid solution with Na2CO3? Either I'm not understanding what you mean or that is a really dumb suggestion.

Damn it now I look like an idiot! Sorry, I meant to suggest the use of CaO not Na2CO3.. that's what happens when I try to multitask. Anyway CaO is kosher with alcohols, I don't know about acid soln's though.

Quote:

Bubbling HCl through an isopropanol solution is a much better way of getting it saturated, but if you are going to use it to crystallise an organic salt and you are going to be working with gaseous HCl anyway, why not just use the HCl gas directly?

It is my intent in this lifetime to (when possible), avoid HCL work like the plague, that's why!

Having a liter or gallon or 6 of preprepared, quantified, anhydrous HCL in isoOH will make future xtallizations much safer, more time-efficient, and ideally more successful (for me anyway; I got problems with overgassing).

I bet isoOH picks up HCL(g) like it's going outta style. Saturation via gassing would probably occur pretty rapidly and without too many stray vapors to ruin metallic belongings and/or various bodily membranes. One way to find out for sure though!

[Edited on 20-2-2014 by zig]

blogfast25 - 20-2-2014 at 06:14

Quote: Originally posted by zig

I'm going to dissolve 37% HCL in 99% isopropyl alcohol, the resulting acidic isoOH will be dried with MgSO4 and used to crystallise a basic organic as the salt. (Conditions must be anhydrous).

[Edited on 20-2-2014 by zig]

I doubt if that's going to work, I think there will be too much water for the MgSO4 to cope with. I think you'll need to lead anhydrous HCl into anhydrous IPA and see where it gets you.

zig - 20-2-2014 at 06:36

Quote: Originally posted by blogfast25

I think you'll need to lead anhydrous HCl into anhydrous IPA and see where it gets you.

Yep, new plan. On the subject of dehydrating agents, can H2SO4 be used to dry HCL gas if it's not at 'fuming' concentration? I think mine is 93%..

turd - 20-2-2014 at 07:36

Been there - done that and it really didn't work out too well. HCl/IPA does not keep forever and some amine salts have quite a solubility in IPA! I'm back to "gassing" from toluene. Could it be that your "overgassing" is due to two things: impurities that act as a pH indicator and wet HCl gas that redissolves some of your product?

NaCl and H2SO4 are dirt cheap and a gassing apparatus with a H2SO4 washing bottle is setup as quickly as a distillation apparatus.

Nicodem - 20-2-2014 at 07:52

Ask yourself why do you even need anhydrous HCl in isopropanol? If your goal is to only make an amine hydrochloride, then all you need is conc. hydrochloric acid, isopropanol, acetone or other suitable solvent, and a rotavapor (or any other apparatus for evaporation).

Quote: Originally posted by zig

Such comical replies might be funny, but if you want others to take you seriously I suggest you to learn the chemical symbols. The symbol for chlorine is "Cl", not "CL". Likewise, making up stupid acronyms like "isoOH" indicates you have no basic knowledge in organic chemistry, which might deter members from helping you (it only attracts replies like "this smells of cookery"). You can call it isopropanol although this is not correct by IUPAC nomenclature, because isopropane does not exist. The most acceptable name is 2-propanol and the correct shorthand abbreviation is i-PrOH or ⁱPrOH. The only acronym I ever saw used is "IPA". Not making appear yourself as someone who does not care about chemistry can help a lot to receive helpful replies (this has been proven over and over again on this forum).

[Edited on 20/2/2014 by Nicodem]

zig - 20-2-2014 at 08:10

Quote: Originally posted by turd

Could it be that your "overgassing" is due to two things: impurities that act as a pH indicator and wet HCl gas that redissolves some of your product?

Two very real possibilites, yep. Since my last failed trial, I've taken the time to fractionally distill the freebase, giving a much prettier looking/smelling oil than before.
HCL gas was generated by dripping c.H2SO4 in c.HCL+NaCl; all dehydration agents tried have been ineffective (solid salts mostly) Consensus seems to say that bubbling through c.H2SO4 is the way to go.. which would be really convenient if 93% is strong enough to dehydrate effectively. I got tons of the stuff.

Quote:

NaCl and H2SO4 are dirt cheap and a gassing apparatus with a H2SO4 washing bottle is setup as quickly as a distillation apparatus.

Oh that's right, still gotta check that out. Sounds a bit more managable than the daisytrain of 5 erlenmeyers I've been utilizing.

zig - 20-2-2014 at 08:59

Quote: Originally posted by Nicodem

Ask yourself why do you even need anhydrous HCl in isopropanol? If your goal is to only make an amine hydrochloride, then all you need is conc. hydrochloric acid, isopropanol, acetone or other suitable solvent, and a rotavapor (or any other apparatus for evaporation).

I may try again now that I'm working with purified phenethylamine freebase, but previous attempts at this method produced oily xtal-ish lumps suspended in a light brown oil. H2O contamination was assumed to be the issue.

Quote:

Jesus, who spit in your coffee? I wasn't trying to be comical- I feel even more foolish realizing I CONSISTENTLY botched Cl in the OP. That's not something I'd have ever done whilst in school, and back then I'd blast someone for such idiocy the same as you.
Apologies for that stupid, stupid acronym- it was laziness that made me do it! The use of iso-OH was informally taught alongside i-PrOH when I took chemistry. Crummy education? Maybe. Thank god the posters of sciencemadness are intelligent enough to figure it out. And I really DO appreciate you correcting me if my acronym is "incorrect" and yours "correct", but c'mon. Isn't isopropanol common enough nomenclature? Are you the IUPAC secret service?

My chemistry is rusty, no doubt, but I've lost no respect for the hobby. I really appreciate the posters willing to offer information and look past all of my grievous shortcomings in dictation.

turd - 20-2-2014 at 09:58

Quote: Originally posted by zig

HCL gas was generated by dripping c.H2SO4 in c.HCL+NaCl; all dehydration agents tried have been ineffective (solid salts mostly)

That seems irrational to me - why would you add water into the system with conc. HCl? Given how incredibly cheap H2SO4 and NaCl are I wouldn't bother with this. You could also try NH4Cl as a chloride source.

PS: It seems you still haven't understood that you can't dry an acid with a base.
Formally: CaO + 2HCl -> CaCl2 + H2O.

[Edited on 20-2-2014 by turd]

bfesser - 20-2-2014 at 11:54

Quote: Originally posted by Nicodem

You can call it isopropanol although this is not correct by IUPAC nomenclature, because isopropane does not exist. The most acceptable name is 2-propanol and the correct shorthand abbreviation is i-PrOH or ⁱPrOH.

So you disfavor isopropanol but you're preffered abbreviation is i-PrOH? Surely you can see how that's contradictory, though, as i is short for iso-. (Yes, I'm aware that this is IUPAC's current preference—but that's committees for you…) I use 2-propanol (IUPAC preferred) or propan-2-ol, personally—less dicking around with italics and no ambiguity or room for misinterpretation (Pr is also the symbol for praseodymium).

zig, "isoOH" is entirely wrong. Either your memory is flawed, or your professor picked up a bad habit in industry. Try to unlearn that habit. Isopropanol is fine, "IPA" is acceptable if you define it first (as you should with most acronyms).

Nicodem - 20-2-2014 at 12:43

Quote:

Then, you are most likely you are not doing it right.

Quote: Originally posted by bfesser

So you disfavor isopropanol but you're preffered abbreviation is i-PrOH? Surely you can see how that's contradictory, though, as i is short for iso-.

It is not contradictory at all. On the contrary it is perfectly logical and complies with IUPAC regulations. That is because it is not an abbreviation, but an accepted shorthand formulae: ⁱPr is shorthand for isopropyl (the Me₂CH- group) and not for for the nonexisting "isopropane". The problem with the "isopropanol" nomenclature is in that isopropanol cannot exist because propane has no isomers. The first isoalcohol that can exist is isobutanol. But the isopropyl group does exist because propane has two nonequivalent substitution sites. I hope I explained it clearly enough.
Otherwise, I just call it isopropanol. It is just fine and sounds better than 2-propanol.

zig - 20-2-2014 at 13:01

Quote: Originally posted by turd

That seems irrational to me - why would you add water into the system with conc. HCl? Given how incredibly cheap H2SO4 and NaCl are I wouldn't bother with this.

I've read that omitting the HCl causes gas generation to be less responsive to addition rate, making it difficult to control as well as suckback issues. I'd rather not deal with two or three suckback flasks. Have you experience with using H2SO4+NaCl? If it's not so bad I'd love to omit the HCl/H2O.

Quote: Originally posted by bfesser

zig, "isoOH" is entirely wrong. Either your memory is flawed, or your professor picked up a bad habit in industry. Try to unlearn that habit.

Duly noted. It was mostly used in lab sections, generally taught by grad students. i-PrOH was the notation commonly used in lecture.

zig - 20-2-2014 at 13:28

Quote: Originally posted by Nicodem

Then, you are most likely you are not doing it right.

Hahaha it's all so clear now!! Why didn't I notice it before!!

thanks Nic!

Quote:

Otherwise, I just call it isopropanol. It is just fine and sounds better than 2-propanol.

Hey we got somethin' in common!

Turd, I'm trusting you! This evening I will connect the necessary safety flasks and give it a whirl sans HCl. Think happy thoughts!

[Edited on 20-2-2014 by zig]

[Edited on 20-2-2014 by zig]

bfesser - 20-2-2014 at 13:44

Nicodem, thank you for elaborating. Your explanation is clear and I concede your point.

[Edited on 26.2.14 by bfesser]

GoldGuy - 20-2-2014 at 15:44

Hey zig

If you want HCl in 99% Isopropanol just put two containers in a larger sealable container. Fill one container with 31.25 Hcl and the other with 99% IPA. Seal and leave for a week not more than 10 days.

http://www.youtube.com/watch?v=jv1Ms6Subg4
Dry IPA with anhydrous MgSO4

[Edited on 20-2-2014 by GoldGuy]

zig - 20-2-2014 at 15:58

And another swing and a miss!

93% H2SO4 was dripped into a layer of non iodized NaCl. HCl gas was bubbled through 93% H2SO4 into a cool soln of 16mL phenethylamine in ~30mL fresh, dry Et2O. Gas was passed through the solution until it took on a cloudy appearance, and HCl fumes were noticeably increased.
At this point the total volume had decreased from ~46mL to ~31mL, presumably due to ethers exothermic acidification traits.
Ether was stripped off, yielding 18mL of a homogenous cloudy oil with a color indistinguishable from the starting freebase. It smelled of spice, with hints of ether.

I don't even know. The product is being chilled to see if it behaves as phenethylamine freebase does at low temp. The 2mL total increase in volume is likely due to not-anhydrous gas..water may also be giving it the cloudy look?

After checking its properties cold, I'll test the pH of the soln. If this is in fact the freebase, untouched, how the hell does that happen?? Something related to the use of ether perhaps? Its the only nonpolar I've got at the moment, shopping day is coming up.

[Edited on 21-2-2014 by zig]

zig - 20-2-2014 at 16:09

Quote: Originally posted by GoldGuy

Hey zig

If you want HCl in 99% Isopropanol just put two containers in a larger sealable container. Fill one container with 31.25 Hcl and the other with 99% IPA. Seal and leave for a week not more than 10 days.

http://www.youtube.com/watch?v=jv1Ms6Subg4
Dry IPA with anhydrous MgSO4

[Edited on 20-2-2014 by GoldGuy]

GoldGuy coming through!! :cool:

That's awesome, simplicity and efficiency at their finest! I'll give this a go next week. Using 12M HCl, I wonder if the alcohol will saturate before reaching 6M.

turd - 20-2-2014 at 23:57

Quote: Originally posted by Nicodem

The problem with the "isopropanol" nomenclature is in that isopropanol cannot exist because propane has no isomers. The first isoalcohol that can exist is isobutanol. But the isopropyl group does exist because propane has two nonequivalent substitution sites.

It may not be IUPAC but to me it was always clear that isopropanol is to be read as iso(propanol) and not (isopropan)ol.

And besides, few things make you appear as noobish as slavishly preferring IUPAC over trivial names. "Ethanoic acid"

zig: for gassing try toluene. And are you positive that you have significant amounts of base? Is it (very) basic to wet universal indicator paper? Because from all you posted it sounds like you have more trash than anything.

[topic restored]

bfesser - 26-2-2014 at 05:29

Further discussion of nomenclature is too far off-topic; I have split it into another thread:
<a href="viewthread.php?tid=29183">Nomenclature Discussion from "prep of HCl in isoOH?"</a>
for those who are interested. Discussion of the chemistry (HCl + i-PrOH) may resume here.

As always, if you have any concerns, please feel free to U2U me.