[quinn123]

Hi

I would like to emulsify mineral (paraffin) oil and water (O-in-W) to form a low viscosity transparent and non-irritable emulsification.  I have tried some surfactants but they all form a cloudy white emulsification.  Can you please recommend a surfactant I can use to achieve this transparent emulsification?  The ratio of water to oil in the formula will be 1:1 + surfactant. 

If you could think of a novel way to temporarily mix oil and water so it can be sprayed out of a bottle that would also solve the issue at hand.

Regards
Quinn

[Arkcon]

A quick Google for "mineral oil emulsifier" led me to two references, the first is a little bit more for novices, however, it does have references of its own:  http://www.livestrong.com/article/214112-mineral-oil-emulsion-ingredients/  Did you try any of those?  What did you get?  The second is more advanced:  http://pubs.acs.org/doi/abs/10.1021/ie50229a024  Maybe that has the answers you need?  What else can you tell us about your application?  What is this for, and what do you know about similar topics?

[Wastrel]

For the emulsion to be transparent the refractive index of the two phases should match.

[Enthalpy]

Or perhaps the droplets be much smaller than a half-wavelength, but they use to be much bigger.

Emulsions are translucid, not transparent - yes, because of the different refractive indices.

[quinn123]

Hi thank you for replies.  I have tried the following product: http://www.vicchem.com/product_detail.aspx?pn=16500.  It gave a good emulsion but was milky/cloudy, which is common with most O/W emulsions due to differences in reflective index of oil vs water and size of droplets in normal O/W emulsion, as has been implied by Enthalpy and Wastel.  It is for a product similar to horticultural sprays to apply a thin layer of mineral oil over any surface.  The emulsion does not have to be 100% transparent, a clear translucent liquid should suffice.

From my research a micro-emulsion or trying to match refractive indexes might be able to achieve the above.  One thing that is putting me off is the increased % of surfactant/co surfactant required to reach micro emulsion, which may be costly and make its use not viable.  I just thought being such common liquids used in emulsification this would have all been done before and there would be a surfactant that could achieve a transparent emulsion.  I suppose it just isn't going to happen because the refractive index's of oil and water are so different.  Maybe if there is another liquid that could be used in place of water to dilute/mix with mineral oil that is readily available at similar cost to water? 

Cheers

[Enthalpy]

Maybe egg yolk as a surfactant is cheap enough to reduce droplets size? Though, emulsions have the nasty habit of rotting (including the oil+water emulsion used for machining) and eggs shouldn't help.

[quinn123]

Hi I may experiment with egg yolk and see what happens but yeah I think rotting would be an issue.

I wonder if LAURIC DIETHA-NOLAMIDE could be possible surfactant.  I saw its only $17 for 5kg.  The below patent from 1965 says it forms a clear emulsion of mineral oil and water.  I wonder if the resulting emulsion will have low enough viscosity?  I assume its relatively benign being used in hair products.  What do you think worth a shot?

http://www.archpatent.com/patents/3175949

[bcoots]

Lauric Diethanolamide (aka Lauramide DEA), is now listed on Prop 65 in California, along with all other DEA amides.

Diisopropanolamide (DIPA) amides are alternatives; these function in the same was as DEA amides.

[quinn123]

Ok thank you Bcoots.

[Enthalpy]

Maybe some alcohols are enough efficient and cheap as a surfactant and are bactericides?
Isopropanol (the one that stinks in hospitals) makes micro-emulsions
1-butanol is also known for micro-emulsions and as a bactericide. Abundent chemical intermediate.

[opsomath]

The most important thing here is your micelle size, you want to get down to "colloid" level particle size. Perhaps ultrasonication could generate sub-micron micelles for you?

Why does it have to be 1:1? I have to say that I don't see that actually happening.