why does the FDA ban the use of lithium-6 deuteride for hydrogen powered vehicles?? thank you
Might it have something to do with safety: Lithium hydride - Wikipedia?
This is an example of a question that is “not even wrong”. You’re welcome.
Stranger
Lithium-6 deuteride is the primary fuel for a Hydrogen bomb. Even if it was possible to use for a Hydrogen-powered vehicle, it’s far too expensive. What advantage does heavy Hydrogen have in this use case?
To give an more complete answer:
- The FDA (Food and Drug Administration) doesn’t ban anything for use in hydrogen-powered vehicles. It regulates Food…and Drugs. I would imagine 6LID is regulated by either Nuclear Regulatory Commission or the Department of Energy. See #2 below.
- 6LID is (as @beowulff noted) the primary fusion fuel in a thermonuclear weapon. It is rare and expensive (and actually may not be available for general commercial purposes - frankly, I can’t imagine why it would be). It is also used as the primary “fuel” for the creation of tritium in nuclear breeder reactors.
- It reacts with water very energetically and releases a strong corrosive as a byproduct. The dust can also catch fire or explode rather easily. Not something you want in a vehicle.
- Finally, as noted by @Czarcasm in his linked article, it takes VERY high temperatures to release hydrogen from the hydrides (around 1300 F) which, again, is not something you really want happening in a vehicle.
What made you think its use was a possibility?
I’ve worked with LiH, and I think you’re mischaracterizing it here.
Lithium Hydride used to be used as a way to store hydrogen in things like emergency rescue balloons. All you had to add was water (unlike making hydrogen by mixing powdered metal with hydrochloric acid). They used it precisely because it wasn’t as reactive as using lithium or any alkali metal. When you mic lithium with water you generate hydrogen but also enough heat to ignite the hydrogen. (mixing sodium or potassium with water is even more violent, releasing a lot more heat and possibly exploding) Mixing lithium hydride with water doesn’t liberate anywhere near as much heat, so you don’t get flame.
As for the by-product, it’s lithium hydroxide, which is a base and corrosive, but if it’s mixed with enough water it’s merely annoying, not a hazard.
I once had a single crystal of Lithium Hydride grown for an experiment we were doing. It was a beautiful light blue. It was so light – in solid form it’s the least dense room-temperature substance, ignoring such structured things as aerogels – that it would float to the top of any oil used to protect it (it would readily rect with any moisture in the air if not immersed in oil). I had to construct a special “cap” to weigh it down under the oil. The kind of LiH they used for inflating balloons to hold aloft radio antennas on life rafts wasn’t so pretty – it was a grayish gritty substance that had to be stored in sealed pouches with dessicants.
Maybe they don’t want you eating it…while driving?
Then you should edit the Wikipedia article which states (under Safety):
LiH reacts violently with water to give hydrogen gas and LiOH, which is caustic.
I don’t know if someone’s been working on it yet, but the Wikipedia article on lithium hydride now has a less drastic description than your cite:
I’ll just point that the o.p. is not asking about just lithium hydroxide, but rather lithium-6 deuteride (6Li-D), which is a precursor for for tritium breeding. It will be left as an exercise for the reader to infer why the o.p. is concerned about the Food and Drug Administration purportedly “ban[ning] the use of lithium-6 deuteride for hydrogen powered vehicles”.
Stranger
Yeah, I know, but I have no experience with Lithium 6 deuteride, and don’t know why the OP is interested in it, either. But I’d expect it to react with water similarly to ordinary LiH.
For the record, here’s the reaction of lithium metal with water:
Here are other alkali metals with water:
Here’s powdered lithium metal with water:
Lots more surface area = faster reaction, and more heat and hydrogen. The comments say that you won’t see bulk lithium creating flame, but I’ve seen it do so. Maybe there was enough powder to cause the reaction, or something.
And for comparison, at about a minute in, here’s lithium hydride and water:
I don’t think the o.p. is interested in the chemical properties per se.
Stranger
Looks like the question is answered. Looks like the FDA didn’t do it because the FDA can’t do it.
You have to admit that a car that can run without gas AND breed tritium is a pretty damn cool car. Drive 10k miles and pay for the car by selling the tritium, you can’t lose!
And you would have to admit that it is neither a food nor is it a drug,
I’m actually the first person in this thread who explicitly pointed that out, so yes, I know.
And I say you don’t know until you try.
Damn.
You win.
And it has been nice knowin’ you. 