Question for you chemical engineers...

[003]

All right... I've got a question for you chemistry gurus. Consider the following compounds:
2-Ethylhexanoic acid, sodium hydroxide, sodium nitrate and sodium tolytriazole.

Does anybody know if it would be safe to expose acrylic to these compounds?

[iandh]

sodium hydroxide, nitrate are OK from personal experience, but will eventually discolor. Other stuff, dunno.

[Clue69Less]

Do you know how concentrated they are? Concentrated NaOH is pretty nasty stuff and it will etch acrylic. 2-Ethylhexanoic acid may plasticize acrylic if it's concentrated enough.

[sirheck]

Do you know how concentrated they are? Concentrated NaOH is pretty nasty stuff and it will etch acrylic. 2-Ethylhexanoic acid may plasticize acrylic if it's concentrated enough.

So in other words he should be careful.?

[003]

Chemical Ingredients (% by Weight)

Ingredient CAS Number Percent Weight

2-ETHYLHEXANOIC ACID 149-57-5 4% - 5%
SODIUM HYDROXIDE 1310-73-2 1% - 2%
SODIUM NITRITE 7632-00-0 0.5% - 1%
SODIUM TOLYTRIAZOLE 64665-57-2 0.1% - 0.5%


For every quart of distilled water, an ounce of the above solution will be added. The rest of the above mixture is just water.

[Soulwind]

I don't have enough chemistry to answer your inquiry but I've got one of my own.

Why are you putting that stuff into your loop?

[F1ZZY]

Why are you putting that stuff into your loop?

Damn good question!!

[003]

Surfactant/pH balancer/corrosion inhibitor.

Anybody know? I have listed the concentrations.

[F1ZZY]

What's the actual stuff (tradename or link) you are putting in? Is it recommended for wc?

I don't think adding cationic sodium salts to distilled water is the best idea personally. Surely it will render it electrically conductive (leak risk). So does PT_nuke though I imagine.

Maybe just add a simple anti-algae (that does not contain metallic salts if poss) and only a few drops. You loading seems a bit high.

[kinghong1970]

this thread makes my head hurt...







baaaaaad...



:D

[Clue69Less]

Chemical Ingredients (% by Weight)

Ingredient CAS Number Percent Weight

2-ETHYLHEXANOIC ACID 149-57-5 4% - 5%
SODIUM HYDROXIDE 1310-73-2 1% - 2%
SODIUM NITRITE 7632-00-0 0.5% - 1%
SODIUM TOLYTRIAZOLE 64665-57-2 0.1% - 0.5%


For every quart of distilled water, an ounce of the above solution will be added. The rest of the above mixture is just water.

At one ounce to a quart, the acid will be at about 0.2% and the NaOH will be less than 0.1%. That should result in a fairly neutral pH because EHA is a weak organic acid and NaOH is a very strong base. The bottom line of all that your plastic should be OK. If it's a commercial part, email them and ask if they use a silicone hardcoat.

[003]

At one ounce to a quart, the acid will be at about 0.2% and the NaOH will be less than 0.1%. That should result in a fairly neutral pH because EHA is a weak organic acid and NaOH is a very strong base. The bottom line of all that your plastic should be OK. If it's a commercial part, email them and ask if they use a silicone hardcoat.

Thank you for the info. The product these compounds are in is Hy-Per Lube Super Coolant.

I ask because I know a lot of ethyls react badly with acrylic. There won't be any reaction between that acid stuff and the acrylic in my loop? I will ask about a silicone hardcoat. Just out of curiosity, what is that and why would I be asking?

[Clue69Less]

Thank you for the info. The product these compounds are in is Hy-Per Lube Super Coolant.

I ask because I know a lot of ethyls react badly with acrylic. There won't be any reaction between that acid stuff and the acrylic in my loop? I will ask about a silicone hardcoat. Just out of curiosity, what is that and why would I be asking?

I wouldn't be surprised if the NaOH is added to raise the pH so that you don't get acid hydrolysis. But that coupled with the low concentration means that it shouldn't be aggressive. WRT the silicone hardcoat, it is a surface treatment common to acrylics to make them resistant to abrasion and also oxidation. So polymers that are succeptible to hazing or crazing after exposure to intense sunlight or acid rain will weather better. Still, within 10 years, you'll see haze at the least if not cracks. By then, hopefully you will have moved on to better toys.


http://www.sae.org/technical/papers/910285

http://www.freepatentsonline.com/5411807.html

http://www.finishing.com/1000-1199/1195.shtml

[003]

Ohhhh.... I get it. You were referring to the acrylic parts having the silicone hardcoat, not the compounds. The parts I have that are made of acrylic are a Swiftech MCRES-Micro and a DangerDen MPC-Universal chipset block, which has an acrylic top.

If it turns out they do not have a silicone hardcoat, would it still be safe to use the hy-per lube in my loop?

Oh, I am assuming the sodium based compounds are dissolved solids. Do I need to worry about any dissolved solids precipitating out of the solution in my loop over time?

[Gunslinger]

My experience with surfactants is when pumped and agitated (waterblock channels) they tend to foam.

[Clue69Less]

My experience with surfactants is when pumped and agitated (waterblock channels) they tend to foam.

For sure surfactants can foam. With a good res and a bubble-free loop, there won't be any air available to make foam in the block. I don't see anything in the OP's components list that looks like a defoamer but triazoles (fungicides) are often packaged with defoamer.

[003]

Ok... so I think I should be all right. If the acrylic parts do not have a silicone hardcoat on the wetted surfaces, will this compound still be safe to use in the aforementioned concentration?

Also would I need to worry about dissolved solids precipitating out of the solution in the loop?

[Waterlogged]

I would worry about the chemical bond holding the acrylic together before the acrylic itself. They're usually pickier than the material itself.

[003]

Well, the only part where that would be an issue is my MCRES-Micro. The MPC-Universal just has a solid acrylic top. I have a spare MCRES-Micro that I could test it in.

[MomijiTMO]

I'm not a chem eng student. I'm well on the way with organic chem though =p.

Anyhoo quick thing to notice is weak acid and strong base so what's the point? You would be screaming fork if something precipitates. The triazole won't react with plexiglass but if you are using something else let us know [Click reactions are called so because they are fast].

[003]

Thanks. Sorry if I'm dense but what do you mean I would be screaming fork if something precipitates?

[Gunslinger]

The chemical reaction between the acid and base will generate heat. Screaming fork, is saying you will be dropping the f-bomb if something happens to your equipment.

[MomijiTMO]

Solid bits in your loop would be like sand blasting your blocks.

[003]

Darn... maybe I will just stick with pure distilled water. It seems like all useful additives use dissolved solids in them, which is not something I want in my loop.