DrMario
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Inverting sucrose, removing acid
I was looking into inverting some sucrose. I have some requirements from the process: 100% inversion and no residual acid, after the process.
My plan is to use phosphoric acid to catalyze the hydrolysis. The reason I opted for H3PO4 is that I can/could (you tell me if the plan is stupid) use
fine zinc powder to treat the inverted solution. Zinc phosphate is insoluble, and I could remove it with filtration.
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Metacelsus
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If you're planning to use this for food purposes, make sure you know exactly what you're putting in there. I recommend using calcium hydroxide instead
of zinc. Calcium phosphate is insoluble, and zinc can contain arsenic and/or cadmium.
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Amos
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I agree with calcium hydroxide or carbonate, provided the phosphate formed is the dicalcium or tricalcium one, as monocalcium phosphate is fairly
soluble. Out of curiosity, would this generate equal parts glucose and fructose, then?
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DrMario
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Quote: Originally posted by Cheddite Cheese  | | If you're planning to use this for food purposes, make sure you know exactly what you're putting in there. I recommend using calcium hydroxide instead
of zinc. Calcium phosphate is insoluble, and zinc can contain arsenic and/or cadmium. |
I have zinc powder "for analysis". No idea how many N that is 
I don't have calcium (metal, hydroxide or carbonate) with me. I thought zinc is rather innocuous, but you are right, cadmium does seem to be a common
impurity.
However, since I am not planning to eat the stuff, I guess I should be fine.
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DrMario
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| Quote: Originally posted by No Tears Only Dreams Now | | I agree with calcium hydroxide or carbonate, provided the phosphate formed is the dicalcium or tricalcium one, as monocalcium phosphate is fairly
soluble. Out of curiosity, would this generate equal parts glucose and fructose, then? |
Yes, it would.
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zed
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Not gonna eat it? Too bad. It makes the most delicious bonbon fillings.
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Ozone
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Get some strong acid cation resin (sulfonated styrene-divinylbenzene). It's quite cheap and most companies (Purolite, Rohm and Haas, etc.) will send
free samples.
Pack this wet into a jacketed column (a big condenser with a wad of glass wool at the bottom will do). Using a heating bath, heat the jacket to 85°C
(or so). Pump a solution of sucrose through this. An equimolar mixture of glucose and fructose should result (some tweaking of flow rate, e.g.
residence time may be required).
If done this way, the catalyst stays in the column. There is no need to remove it. If you use pure sucrose, the pH going out should be around 4. This
isn't so bad because there is nil for buffering capacity. Avoid salt in your feed that may displace H+.
This is how invert is made commercially. Of course, you can just toss some in a flask (it doesn't take much, maybe 0.1-0.5% sugar), reflux, and filter
it out.
Cheers,
O3
[Edited on 25-10-2014 by Ozone]
-Anyone who never made a mistake never tried anything new.
--Albert Einstein
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DrMario
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Hey Ozone, thank you - unfortunately, I didn't notice this thread had other replies so I didn't see your method before I did the inversion last night.
I got my hands on some calcium hydroxide. Inverted the sucrose using phosphoric acid as catalyst, and then added Ca(OH)2. The amount of Ca(OH)2 was
sufficient to produce dicalcium phosphate. First to form is calcium monophosphate, which is fairly soluble. But because there is excess Ca(OH)2, I
figured that eventually dicalcium phosphate will be formed. Dicalcium phosphate is poorly soluble, and I decanted it at the end.
I did a nice blue bottle experiment with the inverted sugar, just to entertain myself.
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DrMario
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Hahah, you are right, it does taste good 
I couldn't resist but to taste a small sample of it. Great stuff - almost exactly like honey, sans the random phytochemicals.
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