Isopropanol (CAS # 67630) alternative 4

[tmusliah]

I am looking for an alternative for isopropanol. We are currently using this for its antifreeze properties, in the washer bottles of our vehicles.
I am looking for a cost effective alternative, which must have the following characteristics:
1)It must be water soluble
2)It must be clear
3)It must either be odourless, or have a pleasant odour
4)It must be non-toxic

The reason for not sticking with isopropanol, is a two fold one. The company we are purchasing this chemical from, is no longer keeping this on its product list, and we are using an expensive solvent as an anti freeze.

Any help will be greatly appreciated. (I'm a little out of my element when it comes to chemistry).

Regards

Trevor

 

[25362]

What was the freezing point depression you are after ?
How much % mass isopropyl alcohol have you used ?

 

[tmusliah]

The product should move the freeze point of the watertoa a temperature of -40 degrees celcius.
The current product is mixed 1 part isopropanol to 2 parts water. (33% solution)

 

[TrevorP]

The freezing point suppression is quite large, so I think that will limit your options somewhat (Good question 25362!). The more obvious ones are methanol, ethanol and ethylene (or propylene) glycol. Methanol and ethanol are cheaper, but has more H&S issues. The ethanol would, of course, need to be denatured.
The following website gives freezing points of all these mixtures in water:

http://www.ashchem.com/adc/chemicals/faq_answer.asp?typeID=3&is_header=N

 

[tmusliah]

Hi TrevorP,

Please can you explain what you mean by "H&S issues"? Are you refering to health and safety issues?
Thanks for the web link. It is very informative. I also see from the tables, that a concentration of 33% isopropanol will only suppress the freeze point to -15 degrees celcius.

Methanol although it does have a lower freezing point, has a flash point of 35 degrees celcius. Bad news for me, because the washer bottle, is in the engine compartment.
I will probably end up going with the ethalene glycol mixture.

Thanks

Trevor Musliah

 

[25362]

Trevor, please note that the pure solvents have about the same TCC flash points, although the flammability range for methanol is wider.

However, of the solutions that depress the water freezing point by 15^oC the IPA-water solutions have the lowest (!), simply because of the higher proportion of alcohol in the mix.

For -15^oC freezing point the alcohol-water solutions are:

IPA, 1:2 Fl Pt: 21^oC
Ethanol, 1:3 Fl Pt: 32^oC
Methanol, 1::4 Fl Pt: 45^oC

The subject of H&S, in particular toxicity and flammability, must always be taken into account whatever the alcohol one selects.
Compatibility of the solvents with rubbers or plastics should also be considered.

 

[btrueblood]

Ugh. Ethylene or propylene glycol in a windshield washer bottle? The idea of the low-MW alcohols is that they will also evaporate fairly quickly, leaving a clean windshield behind. The glycols won't, and instead will leave a sticky residue behind that will gather more grime/grit, which will adhere to the wiper blades and grind away at the windshield glass.

Adding ammonia to water will lower the freezing point quite a bit also, and is the formula used by most commercial glass/window cleaners.

 

[25362]

A pitty that no odor, or an aromatic one, is given as a constraint.

 

[mbeychok]

Tmusliah:

If you were happy with the use of isopropanol, why look for an alternative simply because your usual supplier no longer carries it? Isopropanol is a very common alcohol and you should be able to find an alternative supplier quite easily ... probably easier than finding an alternative anti-freeze.

Many drugstores (at least in the USA) sell isopropanol as a rubbing alcohol. Perhaps you could ask one of them who their supplier is. Or contact a chemical supply company listed in your local phone book's business section.

Milton Beychok
(Contact me at www.air-dispersion.com)

 

[btrueblood]

25362,

Yes, and a pity too that "non-toxicity" is listed. Of the earlier quoted candidate materials, only propylene glycol could be considered truly non-toxic, the rest are all systemic toxins. Of course, who'd want to drink windshield washer fluid? But then, that presumes common sense.

 

[IRstuff]

Note that in many locations EG is considered to be, and is, a hazardous material. As such, I don't think that it would be allowed to be used in any application that may allow it to enter the sewage system.

Note also, that the freezing point depression you're asking for usually requires a high (>50%) concentration EG or PG, compounding the EG hazardous material situation. Additionally, at -40ºC, both of these have increasing viscosity and your pump might not have enough oomph to move the liquid.

Since you appear to be satisfied with the existing solution and its associated FP depression, I wonder what the rationale is for requiring the additional FP depression?


TTFN

 

[25362]

A 30% mass EG solution (for a -15^oC freezing point) has a viscosity of just 2 cP at 20^oC.

It is not the anti-freeze effect, or the vaporization of the solvent, but the addition of some detergent to the washing solution that ensures the windshield cleaning effect with help from the wiper blades.

Even non-denatured ethyl alcohol, depending on its manufacturing and refining procedures, may contain some methanol, IPA, and benzene.

Thus, besides causing inebriation upon drinking them, ethyl alcohol windshield-cleaning solutions may be toxic indeed.

 

[StoneCold]

25362
You are on to something. Put wiskey in the windshield washer fluid bottle. Then if you break down some where you are able to just sit back, drink some windshield washer fluid and wait.

 

[IRstuff]

The additional of alcohol, as far as I know, does the following things:
> depressed freezing point allows the fluid to actually get to the windshield

> same effect allows the fluid to liquify the frozen ice already there

> same effect prevents the fluid itself from freezing onto the windshield.


From personal experience, I've learned not to use windshield wipre fluid that doesn't contain alcohol in subfreezing weather. Nothing worse than trying to remove a teensy layer of frost from the windshield and wind up with a big frozen mass of wiper fluid on the windshield.

TTFN

 

[unclesyd]

You can purchase the windshield washer fluid in drums if you desire. We used it in 55 gal polyethylene drums.