Isopropyl vs Isoproponol?

[djos]

G'day all, just curious as to what folks think (not starting a religious war I hope), I've always referred to my favorite cleaning alcohol as "isopropyl alcohol" but I've noticed recently that some folks (including Dave) refer to it as "Isoproponol alcohol".

I assume we are all referring to the same stuff, just wondering what preference others have when referring to it?

[IanB]

There are different names for the same thing. The common name is "isopropyl alcohol", while a more formal chemical name is "isopropanol" (not isopropanol alcohol), and a really precise chemical name is "propan-2-ol" (but nobody calls it that in real life).

Either isopropyl alcohol or isopropanol are fine, just pick whichever one is easier for you to say.

[rob77]

Wikipedia

Isopropyl alcohol, also called isopropanol or dimethyl carbinol, is a compound with the chemical formula C?H?O or C?H?OH or CH?CHOHCH?. It is a colorless, flammable chemical compound with a strong odor.

[djos]

There are different names for the same thing. The common name is "isopropyl alcohol", while a more formal chemical name is "isopropanol" (not isopropanol alcohol), and a really precise chemical name is "propan-2-ol" (but nobody calls it that in real life).

Either isopropyl alcohol or isopropanol are fine, just pick whichever one is easier for you to say.

Cheers, great explanation.

[stj]

engineers just call it IPA.
more importantly, make sure it's atleast 99% pure.
stuff sold for medical use is often 70% or less, the rest is distilled water.

[Macbeth]

Jesus H Christ, don't get me started on Di-hydrogen monoxide. As deadly as it is...

[Fsck]

There are different names for the same thing. The common name is "isopropyl alcohol", while a more formal chemical name is "isopropanol" (not isopropanol alcohol), and a really precise chemical name is "propan-2-ol" (but nobody calls it that in real life).

Either isopropyl alcohol or isopropanol are fine, just pick whichever one is easier for you to say.

Cheers, great explanation.

it can also be 2-propanol.

[2N3055]

Jesus H Christ, don't get me started on Di-hydrogen monoxide. As deadly as it is...

LOL... There was even a satirical web site preaching dangers of it... 

[djos]

engineers just call it IPA.
more importantly, make sure it's atleast 99% pure.
stuff sold for medical use is often 70% or less, the rest is distilled water.

Good point, IPA is what I used to call back in the 90's as a HW Tech talking to other tech's, now I refer to it as Isopropyl Alcohol when telling my mates what to use to clean up their old 80's/90's computer PCB's if they've had a battery leak.

[lwatts666]

While on a business trip to central India, we followed a tanker truck with a hand painted contents safety sign on the back. It stated that the contents on the tanker was "ISO_PAPAL_ALCOHOL".

[stj]

you clean a pcb battery leak with vinegar.

[stj]

While on a business trip to central India, we followed a tanker truck with a hand painted contents safety sign on the back. It stated that the contents on the tanker was "ISO_PAPAL_ALCOHOL".

it was blessed by god! 

[djos]

you clean a pcb battery leak with vinegar.

I've heard of people using lemon juice as well, personally I use a proper PCB cleaner that is based on IPA but has some solvents in it too.

[Fsck]

you clean a pcb battery leak with vinegar.

I've heard of people using lemon juice as well, personally I use a proper PCB cleaner that is based on IPA but has some solvents in it too.

using lemon juice just sounds really icky because I envision biological residue.
Why not just use bulk citric acid in that case? If you buy 20-50lbs at once, it's pretty cheap stuff and often used for descaling.

[stj]

any mild acid works, your destroying the alkaline with it.

[djos]

you clean a pcb battery leak with vinegar.

I've heard of people using lemon juice as well, personally I use a proper PCB cleaner that is based on IPA but has some solvents in it too.

using lemon juice just sounds really icky because I envision biological residue.
Why not just use bulk citric acid in that case? If you buy 20-50lbs at once, it's pretty cheap stuff and often used for descaling.

Yeah vinegar certainly sound preferable to me too.

[helius]

There are two main ways that chemical names are formed. The older method is called "radicofunctional" and names a radical + a functional group. Alcohol is a functional group (the -OH moiety), and isopropyl is the name of the isopropyl radical. So it is written radical + function, isopropyl alcohol.
The newer method which is recommended by chemical societies is the "substitutive" method. This method is more general and can describe many chemicals that have no precise name under the radicofunctional system. The name consists of a base molecule (usually an alkane) and then is decorated with affixes according to the positions at which H atoms are substituted by other residues. There is a long list of rules about how exactly the substitutions are recorded, but in principle it provides a single, unambiguous name for any compound.
The base molecule is propane, and it has one of its H atoms substituted by OH at the 2 position. So it is named Propan-2-ol. The rules fill an entire book, but you can get the gist of it by browsing http://www.acdlabs.com/iupac/nomenclature/

"isopropanol" is completely nonstandard and fails to follow either set of rules.

[kxenos]

The common name is "isopropyl alcohol"

Shouldn't it be Isopropylic Alcohol?

[IanB]

Shouldn't it be Isopropylic Alcohol?

No, that's not correct in English.

[SL4P]

BUT CAN YOU DRINK IT ?

[IanB]

BUT CAN YOU DRINK IT ?

You can drink anything. Should you drink it is another matter.

[djos]

BUT CAN YOU DRINK IT ?

You can however you likely won't survive the experience.

[wraper]

BUT CAN YOU DRINK IT ?

Yes you can. The question is: can you do this more than one time?

[djos]

There are two main ways that chemical names are formed. The older method is called "radicofunctional" and names a radical + a functional group. Alcohol is a functional group (the -OH moiety), and isopropyl is the name of the isopropyl radical. So it is written radical + function, isopropyl alcohol.
The newer method which is recommended by chemical societies is the "substitutive" method. This method is more general and can describe many chemicals that have no precise name under the radicofunctional system. The name consists of a base molecule (usually an alkane) and then is decorated with affixes according to the positions at which H atoms are substituted by other residues. There is a long list of rules about how exactly the substitutions are recorded, but in principle it provides a single, unambiguous name for any compound.
The base molecule is propane, and it has one of its H atoms substituted by OH at the 2 position. So it is named Propan-2-ol. The rules fill an entire book, but you can get the gist of it by browsing http://www.acdlabs.com/iupac/nomenclature/

"isopropanol" is completely nonstandard and fails to follow either set of rules.

Nice one, now some brave soul just needs to tell Dave to say isopropyl properly in future videos!

[imidis]

Hmm, I don't believe I would dare try. I generally go with Isopropyl.

[rs20]

engineers just call it IPA.
more importantly, make sure it's atleast 99% pure.
stuff sold for medical use is often 70% or less, the rest is distilled water.

Ah, the old fallacy that stronger is always better. Water is an excellent solvent cleaning agent, so the team of 30% water, 70% IPA can be a better cleaner than 100% IPA. The latter is only preferable in situations where water is unacceptable, or if you're using the IPA specifically to speed up drying.

[stj]

water is unacceptable when cleaning flux, it hardens it and makes IPA less effective.

[IanB]

water is unacceptable when cleaning flux, it hardens it and makes IPA less effective.

Unless it is water soluble flux. Or if in the case above, you are cleaning leaked battery residues. It all depends on the specifics of what you are cleaning. There is no single universal solvent.

[Cubdriver]

water is unacceptable when cleaning flux, it hardens it and makes IPA less effective.

Unless it is water soluble flux. Or if in the case above, you are cleaning leaked battery residues. It all depends on the specifics of what you are cleaning. There is no single universal solvent.

Exactly.  Horses for courses.  I try to keep all manner of stuff around - IPA at 91 & 99%, denatured alcohol, acetone, lacquer thinner, mineral spirits, MEK, naphtha, distilled water, various commercial products like Windex, Goof Off, Fantastic and whatnot - as different situations call for different cleaning solvents.

-Pat

[magetoo]

IPA has slightly lower LD50 than ethanol, so there is no reason why it can't be used as a drink.
In fact, even methanol is used (as a byproduct of natural brewing process), along with IPA and n-butanol (natural or artificial) as flavor enhancement agents in alcohol spirits.

Interesting.  I suspected that isopropanol wouldn't be very harmful, given that it's so widely used for things like hand sanitizer in hospitals.  (If it were acceptable to leave containers of instant liquid death unsupervised in places the public have access to, surely there would be cheaper options.)

[macboy]

BUT CAN YOU DRINK IT ?

IPA has slightly lower LD50 than ethanol, so there is no reason why it can't be used as a drink.
In fact, even methanol is used (as a byproduct of natural brewing process), along with IPA and n-butanol (natural or artificial) as flavor enhancement agents in alcohol spirits.

Really, "no reason" at all? That's rather dangerous advice.
Isopropyl alcohol will cause blindness at best, at worst you will die. Methanol is as bad or worse.
Now, I don't deny that there may be a little bit of each in ethanol based spirits. The trick is that the other alcohols are far less dangerous to the body when there is also a large quantity of ethanol present. In fact, one treatment used for poisoning by methanol is to administer a large quantity of ethanol as an antidote which prevents formation of toxic metabolites. They literally keep the patient drunk until their body can remove the dangerous alcohols. If you drink either methanol or isopropanol on their own, you are done for.

[N2IXK]

I drink IPA fairly often.

Lagunitas and Dogfish Head make quite good varieties of the stuff....

[coppice]

"isopropanol" is completely nonstandard and fails to follow either set of rules.

Isopropanol was a "standardised" name for a while, as the world migrated from isopropyl alcohol, through a series of not quite making its mind up steps, to propan-2-ol (with or with the - and -, which also seemed to go through a period of flux).

Our first high school chemistry text book said isoproyl alcohol. Our later ones said isopropanol. Our teacher said propan-2-ol by the end of our schooling.

[SeanB]

any mild acid works, your destroying the alkaline with it.

I use ascorbic acid, and it works well to clean aluminium heat exchangers internally of scale.

BUT CAN YOU DRINK IT ?

IPA has slightly lower LD50 than ethanol, so there is no reason why it can't be used as a drink.
In fact, even methanol is used (as a byproduct of natural brewing process), along with IPA and n-butanol (natural or artificial) as flavor enhancement agents in alcohol spirits.

Benzyl alcohol is not good to clean with, it is really good at dissolving many plastics. However methanol is a great cleaner, and is available as a very pure chemical and is very cheap, sold as racing fuel.

[rs20]

However methanol is a great cleaner, and is available as a very pure chemical and is very cheap, sold as racing fuel.

Just be aware that it burns with an invisible flame, which is slightly scary. Also it ostensibly makes you blind if you somehow ingest (and hold down) 5mL of it.

[BradC]

However methanol is a great cleaner, and is available as a very pure chemical and is very cheap, sold as racing fuel.

Just be aware that it burns with an invisible flame, which is slightly scary. Also it ostensibly makes you blind if you somehow ingest (and hold down) 5mL of it.

From memory it metabolises to formaldehyde and blocks capillaries in the retina. Not a particularly nice thing to happen.

[Macbeth]

What a pile of big girls blouses - it takes Big Clive

to swig some proper meths.   

[Nerull]

However methanol is a great cleaner, and is available as a very pure chemical and is very cheap, sold as racing fuel.

Just be aware that it burns with an invisible flame, which is slightly scary. Also it ostensibly makes you blind if you somehow ingest (and hold down) 5mL of it.

Not just ingest - methanol will absorb through skin. So wear gloves.

I knew a guy who got methanol poisoning from a torn glove in a cleaning tank.

[Nerull]

What a pile of big girls blouses - it takes Big Clive

to swig some proper meths.   

Of course, if you paid attention to at least the first 10 seconds of the video, you'd know that methylated spirits is another name for denatured alcohol - which is 99% ethanol. And even only 1% methanol present, he makes sure to point out several times that he is absolutely not swallowing any.

[magetoo]

Really, "no reason" at all? That's rather dangerous advice.
Isopropyl alcohol will cause blindness at best, at worst you will die.

Blindness is specific to methanol, because as you mention further down, it breaks down into formaldehyde and other nasty stuff that messes up your eyes by some mechanism I'm too lazy to look up.

From what I can tell, isopropanol is treated as toxic everywhere I've looked it up, but the effects seem to be much more similar to overdosing on ethanol than anything else.  My bottle of 99.5% IPA doesn't even have the skull symbol on it.

It might be more potent or harder for the body to get rid of compared to ethanol, or harmful in some other way though, I'm not about to try it.

[BradC]

Of course, if you paid attention to at least the first 10 seconds of the video, you'd know that methylated spirits is another name for denatured alcohol - which is 99% ethanol. And even only 1% methanol present, he makes sure to point out several times that he is absolutely not swallowing any.

The denaturant in Metho is pretty region and manufacturer specific. There are a couple of brands in Oz that don't have _any_ methanol in them. They use another approved denaturant and a bittering agent to make it taste foul. Again, the bittering agent is manufacturer specific.

[helius]

The most common denaturing agent (by far) is denatonium (Bitrex), which is a lidocaine derivative.
The reason that methanol (and not just bitterant) is added to denature alcohol is to discourage its use as an untaxed source of drinkable ethanol through filtration or distillation.

There are a range of specific formulas approved for specialized uses, which may not use the same denaturants as methylated spirits. These are designated "SD[number]" for Special Denatured: for instance, SD alcohol 40 which is found in cosmetics and shaving creams.

[grifftech]

Jesus H Christ, don't get me started on Di-hydrogen monoxide. As deadly as it is...

  water

[tooki]

BUT CAN YOU DRINK IT ?

IPA has slightly lower LD50 than ethanol, so there is no reason why it can't be used as a drink.
In fact, even methanol is used (as a byproduct of natural brewing process), along with IPA and n-butanol (natural or artificial) as flavor enhancement agents in alcohol spirits.

Given that I've seen isopropyl alcohol used as a denaturing agent for ethanol, I'm pretty sure it's not considered safe to consume.

[SeanB]

However methanol is a great cleaner, and is available as a very pure chemical and is very cheap, sold as racing fuel.

Just be aware that it burns with an invisible flame, which is slightly scary. Also it ostensibly makes you blind if you somehow ingest (and hold down) 5mL of it.

From memory it metabolises to formaldehyde and blocks capillaries in the retina. Not a particularly nice thing to happen.

Yes, i know, and still remember the burn. But i have healed with almost no scarring, thanks to liberal application of spray skin immediately after cooling in the pool water.

AFAIK the remedy for methanol ingestion is to drink Vodka, till you get to well over the legal limit, and keep on drinking for 2 days till all the methanol is excreted via the kidneys. Ethanol is a preferred reagent in that chemical pathway so putting enough in saturates the chemistry and then the methanol is going to be filtered out by the kidneys, so you just have to provide a diuretic ( Which is the ethanol in any case) and enough water so the kidneys are driven into keeping your blood thick enough. You lose liver function, quite a few brain cells and some renal function, but there is enough redundancy there to survive with.

[Macbeth]

AFAIK the remedy for methanol ingestion is to drink Vodka, till you get to well over the legal limit, and keep on drinking for 2 days till all the methanol is excreted via the kidneys. Ethanol is a preferred reagent in that chemical pathway so putting enough in saturates the chemistry and then the methanol is going to be filtered out by the kidneys, so you just have to provide a diuretic ( Which is the ethanol in any case) and enough water so the kidneys are driven into keeping your blood thick enough. You lose liver function, quite a few brain cells and some renal function, but there is enough redundancy there to survive with.

Yes, the antidote to methanol is drinking (or having a blood infusion) of pure ethanol.

When you think about it the addition of "wood alcohol" methanol which is far more expensive to produce than ethanol and so used merely as an adjunct is criminal - it is there purely to blind or kill people who don't want to pay the state taxes on their preferred substance of abuse. The disgusting taste should be enough to protect the Chancer of the exchequers purse - not killing poor and mentally ill people just because they tried avoiding HMRC alcohol duty.

[jpanhalt]

@MacBeth  If you are implying that denatured ethanol today is denatured with methanol, that is not correct.  There are several denaturing concoctions (17 at my last count) that are approved for consumer use.  NONE are intentionally poisonous in the sense of methanol.  Most are either terrible tasting or cause nausea.  At least it is that way in the US.

John

[Cerebus]

I'm sorry to disappoint all the folks who are making isopropanol out to be deadly, but it's an approved food additive in most of the world. It's used is as a carrier solvent for flavourings and the European ADI (Acceptable Daily Intake) is set at 2.4 mg/kg body weight*. By comparison, a tentative ADI for Ethanol was proposed at 100 mg/kg (NIH) and I could find nobody who had set an ADI for methanol.

The EU and US occupational exposure limits (PEL TWA) for isopropanol , ethanol and methanol are 400ppm, 1000 ppm, and 200 ppm respectively.

The primary metabolic route for all these simple alcohols is dehydrogenation by, unsurprisingly, the enzyme Alcohol-Dehydrogenase and it is this that turns methanol into formaldehyde. Ethanol gives you acetaldehyde, and isopropanol gives you acetone, both readily dealt with by other enzymes whereas formaldehyde (from methanol) is not. My copy of the classic "Biochemical Pathways" wall chart is stuck in a box somewhere or I'd scan the relevant section and upload it.

*The EFSA Journal (2005)202, 1-10

[Macbeth]

Of course, if you paid attention to at least the first 10 seconds of the video, you'd know that methylated spirits is another name for denatured alcohol - which is 99% ethanol. And even only 1% methanol present, he makes sure to point out several times that he is absolutely not swallowing any.

Cool story Bro!  I've no idea why you point out all this obvious stuff which I haven't disputed, quite the opposite??

[Macbeth]

@MacBeth  If you are implying that denatured ethanol today is denatured with methanol, that is not correct.  There are several denaturing concoctions (17 at my last count) that are approved for consumer use.  NONE are intentionally poisonous in the sense of methanol.  Most are either terrible tasting or cause nausea.  At least it is that way in the US.

John

That's good to hear, I am pretty damn sure that old fashioned "meths" was absolutely denatured with methanol in the UK (5% IIRC). Perhaps they now rely on the purple colour and disgusting taste instead which at least allows winos to not die or go blind when living it up partying on the streets.

There is also a lot of nonsense about distilling which is illegal in most of the world, and "first runnings" - which would contain the <0.05% methanol in a fermentation bin. Home distilling (which is legal in NZ) on a small scale like a 5 gallon wash could not possibly produce enough methanol to do any damage. However, it's simple enough to deal with the first thimble full before the liter or so of ethanol comes spurting forth.

[IanB]

@MacBeth  If you are implying that denatured ethanol today is denatured with methanol, that is not correct.  There are several denaturing concoctions (17 at my last count) that are approved for consumer use.  NONE are intentionally poisonous in the sense of methanol.  Most are either terrible tasting or cause nausea.  At least it is that way in the US.

John

That's good to hear, I am pretty damn sure that old fashioned "meths" was absolutely denatured with methanol in the UK (5% IIRC). Perhaps they now rely on the purple colour and disgusting taste instead which at least allows winos to not die or go blind when living it up partying on the streets.

Don't worry, jpanhalt is quite mistaken. One of the main brands of denatured alcohol available all over the USA contains up to 5% methanol as its primary denaturant. I have a can of it in my garage.

The same is true of many formulations sold in the UK.

I suspect that 5% methanol is chosen so that consumption is unpleasant without immediately killing you.

[jpanhalt]

@Ian B
I stand corrected.  Thank you for pointing that out.
 
The basis for my original comment goes back at least 10 years when I had noticed some denatured alcohol was surprisingly aggressive on a plastic I was using.   Upon looking up the formulations, I found it did not contain methanol and was surprised with the large number of possibilities.  On further research today, there appear to be at least 3 formulations of approved SDA (specially denatured alcohol) in the USA that have methanol (excluding those with gasoline).   Number 3A and number 30 have only methanol, which is what I will be looking for.
Here's a link to thelist: http://www.ecfr.gov/cgi-bin/retrieveECFR?gp=&SID=43a9d82d6f4233f9ef9cfda85850516b&mc=true&n=pt27.1.21&r=PART&ty=HTML

None of the five formulations of completely denatured alcohol (CDA) contain methanol.

According to Wikipedia, the EU in 2013 proposed eliminating the formulations with methanol as has New Zealand.

EDIT: Here's a link to the government definitions of SDA and CDA: https://www.ttb.gov/industrial/sda.shtml   Apparently SDA is more for industry; however, the gallon of Klean-Strip I have from a big box is an SDA with methanol and methyl isobutyl ketone in it.   

John

[Kjelt]

Perhaps they now rely on the purple colour and disgusting taste

In the Netherlands it is blue and called "spiritus" . You can remove the blue colour by passing the fluid through a coffeefilter with some activated carbon. Try it on the purple stuff, maybe it is better carbonfilter resistant. The reason to clean it is when you use it as a cleaning fluid after it evaporates the colour leaves a visible mark, not cool.

[Psi]

Just to complicate IPA even further 

[Kjelt]

Wouldn't drink that 

[Psi]

Sam is smart.
Sam discovered he could get 5L if India Pale Ale for super cheap from the local chemical supplier
Sam is now dead.
Don't be like Sam

[TheAmmoniacal]

The chemophobia is strong on this one! Apart from being about twice as effective of a CNS depressant as ethanol, isopropanol is completely harmless (or as harmless as you would consider ethanol). 

[jpanhalt]

Diethyl ether is also pretty good and was used as intoxicant for several years.  Its one advantage is that you can recover sobriety more quickly.

John

[TheAmmoniacal]

Diethyl ether is also pretty good and was used as intoxicant for several years.  Its one advantage is that you can recover sobriety more quickly.

John

Fun fact. You can get relatively pure diethyl ether in most hardware stores as a motor start(er) spray, usually 30% diethyl ether in LPG (butane and propane). If you just puncture the can (with a normal can opener) the gases escape leaving you ~1/3rd of the can with diethyl ether!

[N2IXK]

Any decent ether starting spray also contains lubricating oil to protect the cylinder walls.

Drinking ether would likely result in highly flammable burps, given the boiling point below normal human body temp. Best not be smoking a cigarette while indulging...

[wkb]

Perhaps they now rely on the purple colour and disgusting taste

In the Netherlands it is blue and called "spiritus" . You can remove the blue colour by passing the fluid through a coffeefilter with some activated carbon. Try it on the purple stuff, maybe it is better carbonfilter resistant. The reason to clean it is when you use it as a cleaning fluid after it evaporates the colour leaves a visible mark, not cool.

Right, for that reason I use "bio-ethanol" as found in every "Action" shop.  No color added to that, and it smells a heck of a lot more pleasant than 'spiritus'.
And it is cheap (i.e. it is denatured ethanol of course so no 'accijns'/tax levied).

[BradC]

Fun fact. You can get relatively pure diethyl ether in most hardware stores as a motor start(er) spray, usually 30% diethyl ether in LPG (butane and propane). If you just puncture the can (with a normal can opener) the gases escape leaving you ~1/3rd of the can with diethyl ether!

Unfortunately over here most of them are dimethyl ether. Significantly lower boiling point and not at all as much fun Also an obnoxiously low octane that has been known to cause severe damage to high compression engines when inappropriately used.

[SeanB]

There are can openers that are not motorised, most are commonly known around the world as a "church key", and just puncture the can.

Best to do this hole at the high end of the can though, and outdoors, away from naked flame, smokers and well away from flammable materials like buildings, trees and people.

I generally depressurise the empty cans using an old screwdriver, to get the remaining gas out, and to be able to crush the can down to fit in the scrap pile, plus to get the 2 glass marbles to add to the fish tank. Marbles are easier to clean than gravel, and can ones are free after using the can, plus I get money for the scrap subgrade steel as well.

[Bryan]

Jesus H Christ, don't get me started on Di-hydrogen monoxide. As deadly as it is...

LOL... There was even a satirical web site preaching dangers of it... 

Apparently they are poisoning the masses by using it to make beer.<g>.

[richard.cs]

In the UK I am pretty sure one brand I use has ingredients listed and was 11% methanol. Standard formulations are listed here: http://www.legislation.gov.uk/uksi/2005/1524/schedule/made

The dual aim is to both make it undrinkable and to add things hard to remove by distillation that will show up in chemical tests.

[TheAmmoniacal]

There are can openers that are not motorised, most are commonly known around the world as a "church key", and just puncture the can.

Best to do this hole at the high end of the can though, and outdoors, away from naked flame, smokers and well away from flammable materials like buildings, trees and people.

I generally depressurise the empty cans using an old screwdriver, to get the remaining gas out, and to be able to crush the can down to fit in the scrap pile, plus to get the 2 glass marbles to add to the fish tank. Marbles are easier to clean than gravel, and can ones are free after using the can, plus I get money for the scrap subgrade steel as well.

This is the type of can opener I was thinking of, and the one I use. Simply pressing the cutting wheel into the can punctures it.

[SeanB]

Provided the can is not being opened at 50C or over, it will not have any explosive disassembly. The can walls and seams are designed to survive with the can at 50C and full indefinitely, and  failure there typically is the nozzle venting the fill gas as it is the safety device.

Piercing the can with a sharp point will not cause it to tear at room temperature, but using a can opener can result in the pressurised contents foaming, so first make a small hole or slit, just by using the opener to pierce the can, then only open fully after the pressure has vented.

[Gyro]

Couldn't you just invert the can to bleed off the gas?  Seems rather easier.