Lens Cleaning

[mshchem]

Ammonia-Free Glass Cleaners - Sprayway Cleaners

Tackle any glass surface with Sprayway Glass Cleaner. It won't drip, run or streak and it's ammonia free. It's the World's Best Glass Cleaner for a reason.

spraywayretail.com

 

[mshchem]

Last IPA I got was from Costco - a 4 pack of 500ml bottles of 99% IPA. I also use it to mix solutions of 1% Benzotriazole for film and paper

Benzotriazole is a bugger to dissolve even in alcohol. I'm going to need to mix up some soon.

 

[gordrob]

I have never had an issue dissolving Benzotriazole in IPA. Trying to get a decent solution in water is difficult. Warming the IPA/ Benzotriazole solution will help it to dissolve quicker.

 

[warden]

The Windex folks took the 2-ethoxy-ethanol and ammonium hydroxide out of Windex, now it's main power is Suggestion!

You just shook the foundations of my world.

 

[Petrochemist]

Not quite. I assume by "alcohol" you mean ethanol. This is an excellent solvent for fats and oils, as is propan-2-ol (isopropanol).
Isopropanol is actually slightly LESS polar than ethanol which makes is slightly better at dissolving non-polar fats/oils.
The main reason isopropanol is preferred is because it is more volatile and evaporates faster, making it less prone to leaving streaks or other residues - important for cleaning lenses.

I doubt anyone is using pure ethanol for cleaning. Absolute alcohol is hard to get hold off & due to taxation VERY expensive, more than 10 times the cost of iso-propanol in the UK. Last time I ordered them for work 2.5litres of iso-propanol was under £10, 1 litre of 'absolute' alcohol was over £100 (and needed special customs & excise paperwork).

The nearest most people get is denatured alcohol which usually contains significant methanol making it somewhat toxic. Bitrex or pyridine are often added to make it unpalatable to try & stop people drinking it & going blind
This denatured alcohol is typically only about 90% ethanol. Without a denaturant it's impossible to distil ethanol from a more dilute aqueous solution & get over about 40% ethanol. Removing the denaturant is difficult too.

Yes iso-propanol is less polar than ethanol (& much less than methanol) but it's not more volatile.
Ethanol boils at 78 C while iso-propanol boils at 82.5 C not significantly different but slightly less volatile.

IPA is prefered because of it's better solvency, cheaper price & the lack of heavy trace components which could be left on the glass.

FWIW Ethanol is not fully miscible with all hydrocarbons, something that has caused minor difficulties in blending high ethanol gasoline products.