[gogiva]

Hi everyone,

I’m trying to reduce the evaporation of a pond I have in my garden with a mixture of fatty alcohols (cetyl and stearyl), and to facilitate the way of pouring it I previously dissolve them with warm ethanol in concentrations in which the mixture is completely homogeneous (molality 2.47 mol/kg). However, when pouring it on the water, some kind of jellyfish-like thing is formed which I suppose should be the fatty alcohols and remains floating with a very unpleasant appearance, in addition to reducing the effectiveness of fatty alcohols to reduce evaporation.

I have searched information in forums and books and I have also tried changing the concentration and temperature, but I have not been able to solve it.

My question is, how can I eliminate this effect? Is it related to the way I pour it into the water or is just a chemical effect?

Thank you in advance

PS: Sorry for my English, trying my best

[Borek]

I’m trying to reduce the evaporation of a pond I have in my garden with a mixture of fatty alcohols

To be honest I don't see how they can help, unless they will create a layer on the surface (which probably won't look good). Bute perhaps I am missing something, where did you got the idea from?

This jellyfish-like thing are most likely your alcohols dropping out of the solution when the water concentration becomes too high (ethanol gets diluted). If so, adding it very slowly (slowly as in dropwise) can help a bit.

[gogiva]

I came across this method a while ago, and it seems (at least in theory) that it works. It is explained a bit in wikipedia https://en.wikipedia.org/wiki/Evaporation_suppressing_monolayers. The results that I have obtained look pretty good but my only problem is this "thing" that I can't get rid of.

I will try to apply as drops with a syringe and see if it helps.

[zarhym]

You can try change alcohol to something not soluble in water, such as ether/EtOAc.

When the organic solvent is evaporated, your fatty acid will form a monolayer on the surface of the water, with the hydrophilic head submerges down into water while the hydrophobic tails point up to the air.

Alcohol is soluble in water, and difficult to evaporate. This often cause emulsion on the surface.