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  1. #21
    Join Date
    May 2013
    Location
    Chardon, Ohio
    Posts
    413

    Default Re: OAV with a fogger

    Quote Originally Posted by msl View Post
    Richard, what in the mineral would cause the death of the hive, Not challenging the statement, wanting to understand the mechanism of action given its history as a mite treatment

    allan- mineral oil will not dissolve OA, its the wrong type of solvent...ie polar vs nonpolar. in a nutshell if it will not mix with water, it will not dissolve OA
    Fogging a mineral oil suspension of oxalic is going to result in no oxalic getting in the hive. At the temps foggers run at you are even too hot to turn the oxalic acid into formic acid. You will make things like carbon monoxide which is probably too low a concentration to do any permanent damage. The fogged mineral oil is well proven to not kill mites in any meaningful number so you have accomplished nothing about killing mites and the mites will probably kill the hive in a year or so if you do not take effective steps to kill them. I suppose there is some faint chance you might be able to fog a water solution of oxalic acid and be effective. Water has such a high heat of vaporization and low boiling point you just might keep the temps low enough to allow the oxalic acid to survive or get converted to formic acid. But, people have been asking about fogging oxalic acid for years now and no one reports any good results supported by mite counts so I have my doubts if it is an effective application method.

  2. #22
    Join Date
    Sep 2016
    Location
    denver colorado
    Posts
    193

    Default Re: OAV with a fogger

    respectfully, formic is caused by a glycerin/oa mix I haven't seen anything saying a FGMO/OA mix will create it, and certainly not water/oa mix, if it did, given the OA we use is a dihydrate to start with and already has water in it you would get formic from the current vaporizers

    I now under your point was the hive would die from mites (as would be expected if FGMO was the only treatment), I had read it as the FGMO would slowly kill the hive thanks for the clarification

    I don't see OA fogging ever becoming an effective treatment, too many things against it

  3. #23
    Join Date
    Jul 2013
    Location
    Geneva, Alabama, USA
    Posts
    192

    Default Re: OAV with a fogger

    ok thanks

  4. #24
    Join Date
    May 2013
    Location
    Chardon, Ohio
    Posts
    413

    Default Re: OAV with a fogger

    Quote Originally Posted by msl View Post
    respectfully, formic is caused by a glycerin/oa mix I haven't seen anything saying a FGMO/OA mix will create it, and certainly not water/oa mix, if it did, given the OA we use is a dihydrate to start with and already has water in it you would get formic from the current vaporizers

    I now under your point was the hive would die from mites (as would be expected if FGMO was the only treatment), I had read it as the FGMO would slowly kill the hive thanks for the clarification

    I don't see OA fogging ever becoming an effective treatment, too many things against it
    What you get from heating oxalic acid depends on several things. If it is just oxalic acid dihydrate and you heat it a bit too hot above the sublimation temperature the oxalic can decarboxylate and give you some formic acid. A bit hotter and you get carbon monoxide. So, the temp window to get formic is pretty narrow. It is also mediated by the metal ions present as many metal ions catalyze these thermal degradation reactions.

    The situation in glycerin is entirely different and has little relation to what happens to straight oxalic acid. In glycerin you first make the ester glycerin monooxalate. This stuff decarboxylates quantitatively starting at just about 100 deg C. You now have the ester glycerin monoformate. If there is enough water present, and in general there will be from both the dihydrate and from the one water made when you esterified, the glycerin monoformate will hydrolyze at temps above about 120 deg C and be driven off as fast as it forms. This is an ancient way to make small amounts of formic acid in the lab.

    Formic acid is unstable starting at temps around 300 deg C. This instability is highly mediated by a variety of catalysts such as acids or metals. Depending on conditions you can make carbon dioxide, carbon monoxide, water and hydrogen. You are going to hit those kinds of temps in a fogger using glycerin solutions and you are going to have free metal ions on the surfaces in the fogger.

    So, it would be surprising if you got any significant oxalic acid or formic acid in the output of the fogger if the oxalic carrier was either glycerin or mineral oil simply due to the high temps. On the other hand a water solution might keep things cool enough to allow oxalic acid to survive, particularly if you used a fairly dilute solution and a pretty high feed rate. Say 5% oxalic acid or less and a feed rate fast enough to hold the exit gas temp below 150 deg C or maybe a bit less. I am not so sure I am wild about pumping exit gas that hot into my hives. Sounds like a good way to cook some bees.

    Like I said, I have been hearing back yard inventors talk about this kind of treatment for years now, but none seem to report good results. So, perhaps it is not such a great idea?

  5. #25
    Join Date
    May 2013
    Location
    Chardon, Ohio
    Posts
    413

    Default Re: OAV with a fogger

    I should add I would not use a fogger for this without wearing a Scott Air Pack for safety. I do not think a normal respirator is enough protection with all the volume coming from a fogger.. And, as a chemist I am hardly chemophobic. I have worked with things so toxic they make cyanide pretty safe.

  6. #26
    Join Date
    Sep 2016
    Location
    denver colorado
    Posts
    193

    Default Re: OAV with a fogger

    very inlightinging. I was able to find and under stand the glyerin/oa reaction and formic break down, but noting good for OA thermal decomp, thank you for taking the time to write it (at my level)

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