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gainer

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Well, then, let me ask another question about glycerol. Is Metol soluble in glycerol? I would expect to find the Metol base to be soluble as it is in propylene glycol, but the H2SO4 is a problem. However, I find what appears to be solution of Metol in glycerol when temperature is raised to about 250 F, and remain dissolved as temperature returns to 20 C. I am guessing that a glycerol sulfate is formed that is soluble in excess glycerol.

BTW, when I am raising these temperatures, I do it a bit at a time. There appears to be a threshold above which solution occurs. I can dissolve 10 grams of Metol in 6 fl. oz. of nearly anhydrous medicinal grade glycerol and still have room for 10 grams of ascorbic acid.
 

Kirk Keyes

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I guess you guys in West Virginia cook your roasts a little different how I prefer mine.

I'd hate to have to choke down a roast that was cooked to 250F - I think it would be overly well done, perhaps burnt. I prefer my roasts to be done to a nice medium-rare, about 135-140F. My chicken about 170F. If it gets to 190F, I find it's way to dry for me.

My oven is certainly going to be 250F (except for that medium-rare roast - I love slow cooking.) It will even be as high as 500F for some things, but I make every effort to avoid touching the oven. And I would avoid having to heat chemicals that hot too.

Not keep in mind that professionally, I've cooked stuff to well over that for doing certain chemical analyses. One in particular was when I used to do fuel testing. I had to do distillation ranges on gasoline and diesel. to do that, you put some in a boiling flask, attach a thermometer and a condenser, and distill 100 mls of fuel over into a graduated cylinder. You recorded the temp for the first drop over, the first 10%, the 50% volume, the last 10%, and the last drop over. I seem to remember that diesels would go up to about 600F for that last drop. Pretty damn hot.

But all that was done using lab equipment, in a fume hood, and with experience doing lab work. I do not recommend the home darkroom people really play with doing stuff like this at home. At least not without proper equipment.
 

Kirk Keyes

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I once worked with a guy that was cooking his turkey for Thanksgiving. He took it out of the oven, and the turkey shifted in the pan, causing him to spill the turkey juice/grease onto his feet. Even though the over was 350F or so, the boiling juice/grease in the bottom of the pan was probably not much more than 212F. Even at that temp, he ended up getting 2nd degree burns on his feet. Not a fun thing to do, especially on Thanksgiving.

It's stuff like that that dissuades me from heating stuff up that hot at home.
 
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gainer

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Kirk Keyes said:
Why??
Click to expand...

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.
 

Alan Johnson

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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.
 
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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?
 

Photo Engineer

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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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gainer

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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.
 
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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.
 

Alan Johnson

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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?
 
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Alan Johnson said:
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?
Click to expand...

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.
 

Kirk Keyes

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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!
 
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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.
 

Kirk Keyes

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I already have soap. I don't need to make it. I get it at the grocery store.
 
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But are you sure it's chemically pure?
 

Kirk Keyes

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Guys, I buy Ivory Soap. It's 99 and 44/100% pure, you know!
 
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