Isopropyl Alcohol

[Tiamat]

Originally posted by: Babbles

Originally posted by: Tiamat

Originally posted by: Eli

Originally posted by: Tiamat
Yup, IPA strikes a great compromise for its cleaning strength while leaving no impurities on the surface. Acetone is a stronger cleaner, but leaves impurities on the surface of what was cleaned.

An experiment that I did during undergrad that I thought was cool was to freeze IPA in LN2. As the IPA approaches it's freezing point in LN2, the mixture turns into a very viscous liquid that is as thick as honey/molasses.

I think you're mistaken. Acetone should evaporate clean away, as long as the acetone is pure in the first place.

Xylene leaves impurities though.

I am not mistaken, and Xylene/Toluene are stronger solvents and do leave impurities. My experience is with silicon wafer degreasing and cleaning in preparation for ultra high vacuum (10E-11 torr) environments.

Generally for mild degreasing, it is good enough to start with acetone, then IPA, then EtOH, then methanol, then degassed DI 18Mohm water. This process allows for better than PPB surface impurity count which is necessary for ultra-high vacuum to be obtained in a timely fashion (hours instead of days).

In the presence of high flowing dry nitrogen, it is possible that acetone alone may not leave significant residue, however, for all intents and purposes, the multi-step graduated cleaning method is generally accepted by all surface scientists and surface chemists.


Looks like silverpig does exactly as I mentioned! I only had to use TCE once, and that was done with the silicon as received from the vender (and following RCA clean). Any other relatively clean manipulation of the substrate only required acetone as the lead solvent.

Stronger solvent is all relative. Xylenes and Toluene are aromatic and non-polar. As such they would be better solvents for cleaning aliphatic and aromatic messes . . . typical fuels and/or oils. Things like IPA or acetone are slightly polar and as such are better solvents for more polar compounds.

Of course it is all relative. I mentioned in my previous post response that my experience is with the degreasing of silicon wafers in preparation for UHV environments.

 

[440sixpack]

Originally posted by: Eli

Originally posted by: silverpig

Originally posted by: Eli

Originally posted by: Tiamat
Yup, IPA strikes a great compromise for its cleaning strength while leaving no impurities on the surface. Acetone is a stronger cleaner, but leaves impurities on the surface of what was cleaned.

An experiment that I did during undergrad that I thought was cool was to freeze IPA in LN2. As the IPA approaches it's freezing point in LN2, the mixture turns into a very viscous liquid that is as thick as honey/molasses.

I think you're mistaken. Acetone should evaporate clean away, as long as the acetone is pure in the first place.

Xylene leaves impurities though.

Acetone DEFINITELY leaves a residue, and I get the CMOS grade stuff. If you put a wafer in acetone then let it evaporate it gets a film of crap all over it. Generally we clean in trichloroethylene, then acetone, then either IPA or methanol to get rid of the acetone residue. This is just for easily soluble organics. There are better cleans which can get the stuff that TCE and acetone can't get.

Hmmm..

Everything I've ever read says that pure acetone evaporates clean away. Are you sure the impurities you're seeing aren't introduced later?

I've gotta run some errands, but will come back to this with more googling.

I can confirm that acetone does not leave any heavy metal impurities, to the ppm range anyway. In my lab we use it to remove paints and surface coatings for lead testing, and we've verified that acetone does not contribute any significant lead or other heavy metals to the samples.

 

[SagaLore]

Originally posted by: TridenTBoy3555
Um, the Iso Alcohol sucks for cleaning really sticky stuff. It will not get that stuff off. WD40 works well though. Just spray some of that on, wait a few seconds... Wipe. All sticky stuff gone. O_O It worked good for getting the sticker residue off my mothers laptop. (Laptop still workz!) Isopropyl alcohol didn't do the job there.

Uh...

um...

 

[silverpig]

Originally posted by: zinfamous

Originally posted by: MegaVovaN
You can get 99% in same places as 91% and 70%...
BTW I do not think 99.9% is stable, it will absorb water from air and become less. Probably same applies to 99% and even 91%?

Another danger is that (reportedly) isopropyl tastes exactly like ethyl (regular), so you won't even notice that you are drinking poison.

same with all types of alcohol.

We regularly order 100% EtOH, but you must assume that as soon as you open the bottle, it's actually closer to 95%, as the absorption is so high.

as such, 100% is best aliquoted into 50mL conicals to reduce the absorption of your stock.

I'm not sure if isopropyl poisoning is the same as with methanol, but the interesting thing is that if you do ingest methyl, the first and best response is to ingest ethyl.

In fact, they'll hook you up to an ethanol IV in the emergency room. This is b/c ethanol is more readily metabolized by the body and as such will allow the methanol to pass through.

I heard a story from one of the medical physics people saying that a couple of homeless guys went into the emergency room one night because they bought a bottle of methanol at the hardware store thinking they could get drunk. The doctors gave them a bottle of vodka and told them to drink it because the EtOH would block the MeOH from doing damage.

The next night the two guys showed up with methanol poisoning again...

 

[zinfamous]

Originally posted by: silverpig

Originally posted by: zinfamous

Originally posted by: MegaVovaN
You can get 99% in same places as 91% and 70%...
BTW I do not think 99.9% is stable, it will absorb water from air and become less. Probably same applies to 99% and even 91%?

Another danger is that (reportedly) isopropyl tastes exactly like ethyl (regular), so you won't even notice that you are drinking poison.

same with all types of alcohol.

We regularly order 100% EtOH, but you must assume that as soon as you open the bottle, it's actually closer to 95%, as the absorption is so high.

as such, 100% is best aliquoted into 50mL conicals to reduce the absorption of your stock.

I'm not sure if isopropyl poisoning is the same as with methanol, but the interesting thing is that if you do ingest methyl, the first and best response is to ingest ethyl.

In fact, they'll hook you up to an ethanol IV in the emergency room. This is b/c ethanol is more readily metabolized by the body and as such will allow the methanol to pass through.

I heard a story from one of the medical physics people saying that a couple of homeless guys went into the emergency room one night because they bought a bottle of methanol at the hardware store thinking they could get drunk. The doctors gave them a bottle of vodka and told them to drink it because the EtOH would block the MeOH from doing damage.

The next night the two guys showed up with methanol poisoning again...

LoL. Enterprising fellas, those.

 

[nismotigerwvu]

Originally posted by: Eli

Originally posted by: Mrvile
I never use 70% because there is too much other "junk" in it. I always have a bottle of 91 lying around, I don't know where you guys are getting 99...

The other "junk" in 70% is distilled water.

Maybe even deionized water.

 

[Demon-Xanth]

I picked up some 70% and some 99% from the local supermarket, the latter was more expensive for a smaller quantity, but I can use it when the weaker stuff just isn't cutting it.

 

[eplebnista]

Originally posted by: MrPickins

Originally posted by: TridenTBoy3555
Um, the Iso Alcohol sucks for cleaning really sticky stuff. It will not get that stuff off. WD40 works well though. Just spray some of that on, wait a few seconds... Wipe. All sticky stuff gone. O_O It worked good for getting the sticker residue off my mothers laptop. (Laptop still workz!) Isopropyl alcohol didn't do the job there.

I like Goo Gone for sticky residue, but we also keep a bottle of 91% Isopropyl around for cleaning up oily things.

Walgreens sells 91%, but I haven't ever seen 99% outside of a chemistry supply catalog.

I use lighter fluid to remove sticky residue left behind by stickers.

 

[ZzZGuy]

Back in say... grade 8 during a science class, a girl went and drank a bottle of some sort of alcohol thinking that "alcohol = drunk", teacher grabbed her (by the neck I believe), bent her over, put a finger down her throat to make her vomit it all back up and sent her to the hospital.

Anyone who is fully mature that thinks drinking Isopropyl Alcohol is a cheap way to get drunk should by all means go ahead and give it a try, make sure you get a big bottle.

 

[TheBloodguard]

Originally posted by: QurazyQuisp
It's amazing.

I'm pretty sure it's the best cleaner there is. It literally cleans everything off of anything. Not to mention, there is no easier way to get drunk off of a dollar. (I've never tried it, I hear it has an amazing hang over, normally followed by death)

/rant

Damn, this thread just cost me $100.