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International Hazard
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Registered: 7-5-2010
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Oxidation of simple sugars to tetrahydroxyhexanedioic acids
I have seen a recipe where ammonium salt of tetrahydroxyhexanedioic acids (for example saccharic and mucic acids) is heated in glycerol to produce
pyrrole. But first thing I need to make are these acids.
I would start with saccharic acid, since glucose is more easily available than lactose. Now I have found a recipe with glucose and nitric acid online:
http://archive.org/stream/classbookoforgan030530mbp/classboo...
But as nitric acid is somewhat hard to obtain, I would like to know alternative methods of oxidation. I suspect that Benedict's solution oxidizes only
one part of glucose, while leaving the other end intact. So that is worthless.
Which alternative methods of oxidation of glucose to saccharic acid could be more efficient and clean than nitric acid one? (without toxic gasses,
etc..)
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Boffis
International Hazard
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Registered: 1-5-2011
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Has anyone ever actually tried the preparation of saccharic and mucic acid (galactaric acid) by oxidizing lactose or just mucic acid by oxidising
galactose? I tried this recently and I initially got excellant results with the raw mucic acid being simply filtered off and washed.
According to the instructions in Vogel the raw material is simply dissolved in a minimum of dilute sodium hydroxide, filtered and precipitated with
hydrochloric acid. The problem I am having is how dilute is "dilute"; it appears that the sodium salt is pretty sparingly soluble too, less soluble in
fact than the monosodium salt so that with 1M NaOH solution you reach a point when it stops dissolving and start precipitating again (as the sodium
salt?) inspite of the fact that theoretically I still haven't added enough. I diluted the reaction mixture but the mucic acid or its sodium salt still
didn't dissolve, infact it appeared that more material was precipitating. Anyone got actual experience of this purification?
I oxidizes 70g of the galactose so I have about 50-60g of mucic acid to purify. I am trying to prepare 2-furoic acid and 2,5-furandicarboxylic acids
so I can probably use the crude material. It is pure white and crystalline direct from the filter.
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