Aerosol internal pressure using 50%oxygen + 50% nitrogen as propellant

Dear all,
I facing some query here, about how much pressure I should set in an aerosol using a mixture of propellant (50% oxygen + 50% nitrogen).
The product contain is just mineral water. I got 2 different size, 75gm & 175gm.
Anyone had done this before? Seeking your kind advice..
thanks

Comments

  • Bill_TogeBill_Toge Member, Professional Chemist
    at room temperature, an enormous amount pressure is required to liquefy oxygen and nitrogen, which is why they are not used as aerosol propellants

    dimethyl ether is the most widely used propellant for water-based products


    UK based formulation chemist. Strongest subjects: hair styling, hair bleaches, hair dyes (oxidative and non-oxidative) I know some stuff about: EU regulations, emulsions (O/W and W/O), toothpaste, mouthwash, shampoos, other toiletries
  • The nitrogen gas is compressed air type, not vapor pressure type of propellant. nitrogen & oxygen soluble very little in water, thus I not know how to calculate the pressure I need in the can.
    my supplier here tell me just using 140 -180psi is enough, but my boss here want to know how to calculate to get that figure..
  • johnbjohnb Member, Professional Chemist
    edited November 2016
    What effect are you hoping to achieve by doing this? It will not be a fizzy drink.

    The mass of the gas(es) loadable into a device of this type is extremely low, such that one inadvertant press of the operating button can result in sudden total loss of propellant and a useless product.

    Pressures in excess of 140PSIG are too high for a general use aerosol (have you ever looked at the thickness of the metal on an aerosol container? Even small changes in temperature can result in large changes in internal pressure - together with a rapid increase in the potential for catastrophic failure of the container.

    50/50 O2/N2 mixtures are dangerously flammable and products containing this mixture must be labelled as such. There is also the increased potential for accelerated rust (corrosion) on the metal components and oxidation sensitive ingredients in your product.
  • Bill_TogeBill_Toge Member, Professional Chemist
    edited November 2016
    @johnb plus, a product that highly pressurised will come out of the valve at about Mach II, with a real chance of injuring someone!

    as I said, these are just a few of the reasons why nobody uses oxygen or nitrogen as propellants
    UK based formulation chemist. Strongest subjects: hair styling, hair bleaches, hair dyes (oxidative and non-oxidative) I know some stuff about: EU regulations, emulsions (O/W and W/O), toothpaste, mouthwash, shampoos, other toiletries
  • BobzchemistBobzchemist Member, PCF student
    Are you using BOV (Bag-on-Valve) technology, or just a standard aerosol? The pressure numbers and propellants your supplier is giving you are typical for BOV systems, where the propellant is completely separated from the product by a flexible bag.

    If you are, then no calculations are possible, since there are way too many variables.
    Robert Zonis, Sr. Formulation Chemist, Beaumont Products "All opinions and comments expressed are my own, have no relation to Beaumont Products, are fully copyrighted, and may not be used without written permission."
  • Thanks for all the advice. 
    Bob, I'm just using standard aerosol can.
  • BobzchemistBobzchemist Member, PCF student
    I don't think that there are any aerosols made here in the US with that method, because it's so hard to get a consistent spray, and because oxygen is so corrosive. You might want to try getting a consultant who works with aerosols - try looking here: https://www.spraytm.com/ 
    Robert Zonis, Sr. Formulation Chemist, Beaumont Products "All opinions and comments expressed are my own, have no relation to Beaumont Products, are fully copyrighted, and may not be used without written permission."
  • What I can remember from working with aerosols we used only Nitrogen @ a few bars when producing water spray.

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