[Blu3]

Hello to all, I am a student in my first year and I have been assigned to use specific chemicals and inorganic salts to create a de-icing fluid.

I have purchased Methanol and I have also got Sodium chloride - this salt is the same salt that we use in our own foods I guess if I am not mistaken. Now I am not sure how to combine these two correctly, and I am looking to create it in a 500ml plastic HDPE bottle. If anyone could help me out and tell me whether I should add water just a bit or not at all and in % tell me how much I should use for each product, would appreciate all the help I can get. Thanks in advanced

Note: I also have blue color in powdered form which I will use to give it a strong blue color.

[Hunter2]

If you want to use it for de-icing the windshield of cars, both is not a good idea. Methanol is poisson and sodiumchlorid is corrosive. Better is to use a mixture of 60% v.v. isopropanole with water.

If not then you can mix the methanole with simmilar amount of water and also dissolving some of the salt.

[Blu3]

Hello Hunter2, first thank you very much for replying, as for the sodium chloride I can use a non corrosive salt that you would recommend but for the Methanol I might have to stick to that for now. Also how much salt would I need to put in this mixture, thank you again.

[naitsabes]

Unfortunately all inorganic salts promote corrosion. So sodium chloride is the best you can take, because it's cheap. I would not use such a solution on my car. Not sure, because in the winter lots of salt is spread on the streets, so much lands on the car anyway. But still..

Methanol really is a bad choice because it is quite toxic. If you want to use it anyway, make sure to use it with care. That means, don't pour it over your hands, make sure that you do not inhale too much (use a bottle which doesn't spray a very fine aerosol) and keep it away from children.

Like hunter said, isopropanol would be better. I would also add some glycerol (not too much).

[Blu3]

naitsabes thank you for replying, would using sodium nitrite instead be a better choice and how much of the salt in gr should I be using for 500ml total capacity?

[Arkcon]

naitsabes thank you for replying, would using sodium nitrite instead be a better choice and how much of the salt in gr should I be using for 500ml total capacity?

Ok Blu:, I'd like to welcome you to the Chemical forums, but since this is an assignment for a class, and not a DIY of your own, we'd like to see son work on your part.  That's all in the forum rules, posted in red at the top of every page.

You have some planning of your own to do. What's a deicer?  What I it supposed to do?  And have you learned any formulas that can relate the chemistry to what you want to achieve?

[naitsabes]

would using sodium nitrite instead be a better choice

Sodium nitrite.. you have a soft spot for using toxic chemicals although it isn't necessary, right? You said you were assigned to use inorganic salts? I wouldn't advise that, for the reason hunter said, but if you "have to" use it, sodium chloride is the best. Simply because it's cheap, readily available and safe. They all do pretty much the same regarding freezing and promoting corrosion.

I don't like to say that, because I am also a newbie here - but Arkcon is right when he says you should do some research on your own. That things are really easy to find on the internet.

[Blu3]

Hi to all, I have been assigned to make a windshield washer fluid and I have made a more cost effective but toxic formula.
The formula for the total capacity of 600L:

I.

• 450L - water
• Methanol 118kg
• Blue coloring 3gr
• Aroma 4ml

I have a misco refractometer and when testing the freezing point I am getting only -15C and this has 25% methanol in it which I believe should give me a much lower freezing point something like -17C or -18C at the least. The methanol I have is 99.9% pure. Out of 600L i take away 25% which leaves me with 450L then those 150L of methanol I convert into kg which sum up to 117.9 but I use an even 118kg but the result is not as I expect any suggestions please. Also I am aware of methanol being toxic but its all I can use.

L = Liters
C = Celsius

[Arkcon]

OK, you've got some numbers, but they're all over the place.  Can you convert them for yourself, and use them in one of the formulas for freezing point depression, as found here: https://en.wikipedia.org/wiki/Freezing-point_depression#Calculation

[Blu3]

Dear Arkon,

I have absolutely no idea how to convert based on that wiki page, thank you for replying. Basically I am just confused as to why my products freezing point is not lower. With methanol being 25% shouldn't my product be -20 at least?. A chemist friend told me that methanol is 1 - 1 so 1% methanol is -1, 10% methanol is -10 and so on.

[Arkcon]

No,  I meant use undergraduate knowledge to convert units, and use the converted values in the Wikipedia page formulas.

Ok, you've got an easier formula: Every 1% is -10.  I don't know if that's true, but you're not trying to put the windshield washer people out of business.  To do son undergraduate work, can you convert weight of methanol, in you volume of water, and get an accurate percent?

[Blu3]

Yep I have done that converted 150L methanol to 118kg based on its weight. Which in turn means 25% methanol in the product. And I meant 1% methanol is -1C, and 10% methanol is -10C not 1% methanol = -10C. In the end with the product having 25% methanol in it what should its freezing point be exactly?. Based on my refractometer:

25% methanol = -16C
20% methanol = -12C

I just wanted to confirm with you experts whether these results are as they should be expected or am I making a mistake somewhere?. Thanks again to all for your help.

[DrCMS]

Blu3 - you have been repeatedly told do some work of your own and come back with a better question than "please do my homework for me, please"

You need to look up:

• methanol/water volume change on mixing
• the difference between %w/w and %v/v and % w/v

You need to find: 

• either an accurate freezing point equation
  
• or probably easier a graph to describe the expect freezing points of methanol/water mixtures
  

Ignore your friends very very rough guide which is nowhere near accurate enough for the work you are doing.

Based on what you have done I think your freezing point results are correct but your description of the % strengths leaves too much out.
 

[Blu3]

Dear DrCMS, I apologize for being a bit naggy, but yes you are right rather than listening to people I should do more research on my own. I was just hoping for a bit of clarification thats all. Thank you for your help.

[naitsabes]

I am just curious, but you didn't really mix 600 liters of this stuff, right?