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Article: Borax Project

  1. #1
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    Borax Project

    My Borax Project
    Borax is useful in many ways. Some of us worry about the purity of the commonly and cheaply available 20 Mule Team Borax. There is another concern in cases where accuracy of weight is important. Borax has 2 possible states of hydration, decahydrate and pentahydrate. If a 100 gram sample of pure borax has pentahydrate and decahydrate mixed, the assay will show a greater weight than 100 grams. If 5 grams of a 100 gram sample are the pentahydrate and the rest the decahydrate, no matter how purely the saple is composed only of sodium tetraborate and water of hydration, the assay will show 101.5 grams of the decahydrate. There is no way you can tell at time of collecting a sample from a large batch of pure mixture how much of each hydrate you are getting.
    A common solution to both problems is literally a solution. A saturated solution of borax at a given temperature contains a known weight of borax expressed as the decahydrate, whether the solid used to make the solution was penta- or decahydrate. If the solution was made saturated and separated from the solid at a low temperature, it will have a constant weight of borax per unit weight of solution at any (reasonable) higher temperature. The weight per unit volume will stay constant enough for most uses.
    A simple way to purify a large quantity of borax at the expense of a smaller amount is to make a concentrated solution in boiling water, allow it to crystallize at a temperature below that desirable for keeping, and decant the clear liquid and discard it or use it for cleaning. The soluble impurities in the original borax are presumed to be uniformly distributed in the liquid, so that if, say, 90% of the liquid is removable by decantation and/or fitering, the remaining impurities will be reduced by 90%.
    656 grams of borax decahydrate are soluble in a liter of solution at 100 C. If the temperature is reduced to, say, 15 C, there will remain only 37.9 gram in the discarded solution. The remaining 618 grams of borax has been cleansed of about 90% of its original soluble impurities and is sufficient to make 16 liters of borax solution.
    When I first proposed this approach it was considered by certain of our resident chemists to be a complicated alternative to paying the money for analytical reagent grade of borax and weighing it to the milligram, even though it is well known among other chemists and for the same reason I stated above that such a degree of precision is not warranted by the uncertainty of the state of hydration of borax. Then, to top it off, I had a senior moment and recommended the use of 10 times more of my borax solution than was proper for D-76. That was seen as proof that I knew not whereof I spoke. Furthermore I made the assertion that 10 times too much borax was not as bad as it might seem. In the process of defending my assertion, I found a variation of D-76 that I may (or may not) call "serendipitol". Serendipity is exemplified by the fellow who accidentally walked barefoot through a certain kind of animal excrement and discovered it to be an excellent cure of athlete's foot. I seem to remember that the animal was of the male bovine type.
    I made 3 liters of D-76, two with 10 times the prescribed amount of borax in the form of 425 ml of a 4.71% solution. To one of these were added 20 grams of boric acid crystals. The third liter was made as old-fashioned D-76, using 42.5 ml of the 4.71% borax solution. The rule of this game was to pretend I didn't know about the extra borax and treat it the same as store-bought. I shot 36 exposures of HP5+, bracketing plus and minus 1/2 stop. Any consecutive 4 frames had all three exposures. As it turned out, the nominal exposure was quite good in all three cases.
    I have three cases to show. Each one shows a low resolution scan of an 8x10 print to show its chiaroscuro and a high resolution scan of a portion of that print to show resolution and granularity. The one labeled "D-76" is Metol, 2 grams, hydroquinone,5 grams, 42.5 ml of 4.7 % purified borax solution, and demineralized water to make 1 liter. "D-76 B+" is Gadget's mistake with 425 ml of the borax solution. As cure of the resulting high contrast, I took a cue from more recent D-76 and added 20 grams of boric acid crystals per liter of the mistake and called it "D-76 BB". I used VC paper. I had the contrast turned all the way down for the D-76 B+ negative and no filtration for the other two. I set printing exposure for each print to make the whitest part of the fuzzy stuff in front of my great granddaughter's teddy bear the same.
    I got the expected high contrast from Gadget's Mistake, but grain and resolution were not seriously affected. Adding boric acid to make D-76 BB brought contrast back to near normal.
    Would there be a technical reason for making D-76 BB? Its pH is lower initially than that of traditional D-76 but its activity is nearly the same, at least on short strips. Its buffering capacity should be greater, both locally and overall, which should make a difference in the effect that different types of agitation make on gradations, but the effect may not be what one is looking for. In any case, it is another possible pictorial control.
    Gadget Gainer

  2. #81
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    Quote Originally Posted by Kirk Keyes View Post
    Why??
    I guess you could try it and see for yourself. All you need do is put a couple of grams of Metol in 100 ml of glycerol and see how long it takes to dissolve at room temperature. All we really want is a solution containing 2.5 grams Metol and 4 grams ascorbic acid in 100 or so ml that is in turn soluble in propylene glycol. Water doesn't work. Glycerol does.
    Gadget Gainer

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    Dissolving 10g ascorbic acid in 180ml glycerol far exceeds the solublity 1g/100ml found by searching 'ascorbic acid solubility glycerol'.
    It appears that 10g/180ml is a supersaturated solution ,that some kind of complex is formed,or that 1g/100ml is not correct.

  4. #83
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    Quote Originally Posted by Alan Johnson View Post
    Dissolving 10g ascorbic acid in 180ml glycerol far exceeds the solublity 1g/100ml found by searching 'ascorbic acid solubility glycerol'.
    It appears that 10g/180ml is a supersaturated solution ,that some kind of complex is formed,or that 1g/100ml is not correct.
    I'm pretty sure you would find that 10 grams of Metol also should not dissolve in 180 ml glycerol, but it did when heated and stayed in solution after cooling. I have not had any luck so far finding any such data. I'll try your entry. Was that in Google?
    Gadget Gainer

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    The figure Alan gives is widely cited and appears to be correct. Maybe you are forming another mystery ester!

    PE

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    I have found that propylene glycol can be formed by heating glycerol to 302 F in the presence of a catalyst, which may be either an ion exchange resin or a small amount of sulfuric acid. In the process of heating Metol in glycerol, the sulfuric acid attached to the Metol was detached and served as a catalyst, and what I may have is Metol base in propylene glycol. As to what becomes of the sulfuric acid, perhaps it winds up as a sulfate of either the glycerol or the propylene glycol. Comments please.
    Gadget Gainer

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    PS: I have dissolved quite a lot of ascorbic acid in propylene glycol, in PC-Glycol. It appears the mystery may have departed from my ester. Shucks.
    Gadget Gainer

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    Quote Originally Posted by gainer View Post
    I have found that propylene glycol can be formed by heating glycerol to 302 F in the presence of a catalyst, which may be either an ion exchange resin or a small amount of sulfuric acid. In the process of heating Metol in glycerol, the sulfuric acid attached to the Metol was detached and served as a catalyst, and what I may have is Metol base in propylene glycol. As to what becomes of the sulfuric acid, perhaps it winds up as a sulfate of either the glycerol or the propylene glycol. Comments please.
    Only the very skilled in the art could figure out where was found what is claimed in the first sentence.Could you give a reference?

  9. #88
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    Quote Originally Posted by Alan Johnson View Post
    Only the very skilled in the art could figure out where was found what is claimed in the first sentence.Could you give a reference?
    I did a Google on glycerol alone and found this on WIKIPedia among the uses of glycerol. It's quite interesting. There is an abundance of raw glycerol. Now that I look back on what I did, I'm quite certain I now have propylene glycol with C and Metol base. The viscosity is very much lower than that of the glycerol I started with, and I added no thinners of any kind.

    I don't think I could have gotten the same result starting with the glycol unless, perhaps, I had heated the mixture more than I usually do. Now I'm out of glycerol and glycol. I was wrong when I said I could get gycerol at any drugstore. The local Rite Aid drug store didn't have any and the clerks didn't even know it existed. Their pharmacy may have it but is closed on Sundays. If your local store has Leader brand, there's a good chance they will have the glycerol. I'd have to go more than 50 miles to try walmart, etc.
    Gadget Gainer

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    I bet your local druggist has some glycerine suppositories you could use. Just engineer a way to remove the impurities and you're set!
    Kirk

    For up from the ashes, up from the ashes, grow the roses of success!

  11. #90
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    There are lots of places like The Chemistry Store who can supply it. Look for soap making supplies. Then you can also make a soap to clean up after the suppositories.
    Gadget Gainer

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