3
$\begingroup$

Sodium acetate trihydrate can be converted to sodium acetate anhydrous easily with an oven. I've been told to quickly store sodium acetate anhydrous in a sealed container because it takes water from the air and turns back into the trihydrate form. It's also non-toxic, and is even sometimes used as a food additive. For these reasons, would sodium acetate anhydrous be viable as a desiccant? Perhaps as a less-toxic replacement for silica gel?

$\endgroup$
  • 2
    $\begingroup$ Many salts can be (and indeed are sometimes) used as dessicants, but what's wrong about silica gel, really? That it is not edible? Why would it be? Your computer is not edible either, so what? $\endgroup$ – Ivan Neretin Jun 18 '16 at 23:31
  • $\begingroup$ @IvanNeretin For lab use, silica gel and other common desiccants would certainly be better, but I figured that something non-toxic (edible, even) would be better for use in, for example, beef jerky packages. $\endgroup$ – Daffy Aug 20 '16 at 2:03
  • $\begingroup$ Now that makes sense. Well, $\ce{CaCl2}$ is another lab dessicant which is more or less edible, but it might be too strong to use on food... Wait, why would beef jerky need a dessicant in the first place? Isn't it usually vacuum-packed? $\endgroup$ – Ivan Neretin Aug 20 '16 at 7:11
  • $\begingroup$ @IvanNeretin I'd imagine it would be for when you open and reseal the package. You'd let moisture from the air inside the bag. $\endgroup$ – Daffy Aug 20 '16 at 8:31
3
$\begingroup$

No, not in most applications. While it may act as a dessicant, it is fairly volatile, so you'll get acetic acid evolving from it in the presence of water. Generally, you don't want to expose what ever you're keeping dry to acid. The two obvious issues when it comes to food uses (ie toxicity concerns) is smell (and taste) and acceleration of spoilage (although in the cases of acidic foods, it might not be an issue). You don't generally want your dessicant mixed into the product so keeping them separate is optimal but with the volatile acetic acid it could be a problem. If you wanted to use its acidity to enhance stability or taste (mixed into the food), then you'd have problems with changes in consistency as water was absorbed.

$\endgroup$
0
$\begingroup$

A quick look at Wikipedia says that the specific surface area of silica gel is 800 m$^{2}$ /g as it has a nanoporous structure. I don't know the figure for sodium acetate but I would think that it does not have such a nanoporous structure and therefore would not have as much capacity to absorb water (note that technically silica gel adsorbs water onto the surfaces inside its pores, rather than acting like a sponge).

Also, silica gel itself is not toxic per se, rather it is the coloured indicators that are added that are not good to eat (cobalt (II) chloride is used, of which the anhydrous form is blue and the hexahydrate purple).

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.