Razzer
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Polydimethylsiloxane
I want to convert polydimethylsiloxane, emulsified in water , to sodium silicate. Does anyone have any ideas or experience of this by any method?
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deltaH
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The Si-C bond is not easily cleaved AFAIK. Speculatively speaking, you could burn it to produce fumed silica (good luck capturing the fumes  ), then dissolved the fumed silica into conc. NaOH.
Fumed silica looks like fluffy white smoke but you should not inhale the particles, they are hazardous to your lungs.
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Praxichys
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Siloxanes are prone to hydrolysis by strong acids or bases.
http://www.astm.org/DIGITAL_LIBRARY/MNL/PAGES/MNL12194M.htm
You might try hydrolyzing it with a strong, hot, well-agitated solution of sodium hydroxide. I assume you are starting with silicone oil?
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Etaoin Shrdlu
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You can make sodium silicate from silica gel and sodium hydroxide. If you're keen on starting with PDMS that's all good just thought I'd mention.
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Dan Vizine
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Quote: Originally posted by Etaoin Shrdlu  | | You can make sodium silicate from silica gel and sodium hydroxide. If you're keen on starting with PDMS that's all good just thought I'd mention.
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That's freaking amazing to watch, pour a beaker half full of silica gel, add concentrated NaOH with stirring and in minutes you have sodium silicate
as a water-white (and pretty damned hot) clear solution. Remember that the Na/Si ratio determines final properties. Keep that ratio as low as feasible
to get better "water glass" as they called it when I was a miniature chemist making H2S and Cl in the kitchen with "The golden book of chemistry" as
my guide. Do you older guys even remember the chemicals we could buy back then? Even in drugstores? That book is the literary equivalent to the
"Necronomicon" today, and our children today should apparently be happy to grow crystals and STFU.
Everyone's heard this, but it's truer by the day...
Q. What do you call 50,000 lawyers on the floor of the ocean?
A. A good start.
"But, what if a child loses an eye somewhere ?", the parents ask. It's a good trade if 5,000 children learn some real science from the same source.
Sucks for him, but life is not without risks. Period.
As to PMDS, I'm not sanguine. Notice the sentence "Strong acids or bases, in particular at elevated temperatures, can cause depolymerization of the
siloxane backbone". That's not the same as forming sodium silicate. The C-Si bonds will not be easily attacked, just as previously mentioned.
BTW, silica gel can be costly. Isn't Celite (like for swimming pools) primarily SiO2? It should work nicely. Dirt cheap.
[Edited on 24-1-2015 by Dan Vizine]
"All Your Children Are Poor Unfortunate Victims of Lies You Believe, a Plague Upon Your Ignorance that Keeps the Youth from the Truth They
Deserve"...F. Zappa
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gdflp
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| Quote: Originally posted by Dan Vizine |
BTW, silica gel can be costly. Isn't Celite (like for swimming pools) primarily SiO2? It should work nicely. Dirt cheap.
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Yes, a wash with dilute HCl might be nice to get rid of any aluminum and iron oxides, but I don't think that those will interfere.
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Megatron
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Some kitty litter is silica gel.
[Edited on 25-1-2015 by Megatron]
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Dan Vizine
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Probably much better than Celite. It's kinda' clearish? Bound to give a less hazy product.
"All Your Children Are Poor Unfortunate Victims of Lies You Believe, a Plague Upon Your Ignorance that Keeps the Youth from the Truth They
Deserve"...F. Zappa
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