Sciencemadness Discussion Board

LiH Production Apparatus Design and Operation

5Qr25Pla - 18-2-2018 at 21:55

this crudely drawn apparatus is meant to produce hydrogen (from the left) and then cool the hydrogen and dry it then heat the hydrogen again and pass it over scored/cleaned lithium metal in a reaction vessel.

before the reaction takes place the vessel is purged with hydrogen.

clad.jpg - 100kB

part - 1 - Hydrogen

The hydrogen is produce from the reaction between water and aluminium and is catalyzed by NaOh. In trials, i was able to successfully produce hydrogen for up to 3 hours with no sign of slowing in a 1 litre reactor after 3 hours the hydrogen production began to slow significantly but i believe this is because of over-saturation of aluminium hydroxide in the water and not so much because of a decrease in catalytic activity from the NaOH.

part - 2 - Drying the Hydrogen

The reaction between the aluminium and the water is quite exothermic with higher quantities of NaOH especially (otherwise though, not enough h2 is produced) and because of this there is an exess of moisture in the vapors coming from the reaction vessel (not to mention very fine particles that are carried by this moisture/vapor). in order to dry the hydrogen and prepare it for reaction with the lithium (as moisture will react with the lithium) it is first directed through a vigreaux/air cooled collumn (to keep as much water in reactor as possible) and then through a distillation adapter and into a coil-type condenser that has been cooled by ice cold water. more moisture is condensed here and is collected in a water trap. after the water trap the vapors travel onwards out through a vaccuum adapter and into stainless steel tubing.

part - 3 - Further Drying the Hydrogen

the stainless steel tubing directs the hydrogen into a trap filled with (currently h2so4. but this is probably not a good idea as if it successfully traps h2o it should release SO2 ??) this is only a precautionary step though as the hydrogen seems to be dry enough already. This step needs to be improved. i need something to dry the h2 and preferably also remove any residual O2 if possible.

part - 4 - Heating the Hydrogen

in this step the tube that the hydrogen is in is heated just before a thermostat. the hydrogen is heated to 200C

part - 5 - Reaction

the hydrogen is reacted with lithium to produce lithium hydride (in a stainless steel reactor that has a top that has an inlet and an outlet and a bottom that comes off)

note: the lithium is scraped on the surface to expose fresh lithium just before reaction.

note 2: in the first experiment the hydrogen was not heated as i am worried about the moisture level of my hydrogen. The reaction was mostly a failure as the lithium was only barely scratched before the reaction but where it WAS scratched was covered with a powder that was easily distinguished from the oxide/nitride/etc layer that normally forms.

note 3: the lithium might need to be cleaned while covered by diethyl ether and then dried by the heated hydrogen for best reactivity. but i am hoping that this is not the case. any info on the reactivity of hydrogen and lithium would be appreciated. im sure its out there. but i havnt looked hard enough i suppose :( ill keep looking though.

Question: how can i dry my hydrogen.

Question 2: moisture seems to be the biggest danger in this experiment and i am confident that the moisture level is really low after the coil condenser already. this being said, would a more experienced person be brave enough to raise the temperature of the hydrogen to say 180C - 200C and attempt to react the hydrogen more quickly/efficiently?

if success happens: i plan to keep it in the reaction chamber (for only a few minutes) under hydrogen and then either attempt to dissolve it slowly in anhydrous ether mixed with aluminium chloride (for storage in the form of LAH) or dispose of it as i am truly afraid of chemicals that can ignite so easily. even if it's not likely.

in the future: if i am successful i hope to share my findings and experiment to find reliable methods for hydride production so that others may benefit.

coil condenser shown below
Graham condenser 2.image.jpg - 36kB

[Edited on 19-2-2018 by 5Qr25Pla]

[Edited on 19-2-2018 by 5Qr25Pla]

wg48 - 18-2-2018 at 23:06

I suggest you put a condenser (a different one than shown in the pic) on top of the flask and add a addition funnel to allow control the gas generation. Then you will not need the column or the first water trap.

Magpie - 19-2-2018 at 01:07

I highly recommend that you read the sections on making LiH in "Small-Scale Synthesis of Laboratory Reagents," a book by Leonid Lerner (known as Len1 to veteran forum members).

This is a valuable synthesis which could lead to LiAlH4, a very useful reductant. I wish you the best of success.

LearnedAmateur - 19-2-2018 at 08:15

An excellent pre-write up, good luck when it comes to carrying out the procedure, certainly not something I’m willing to try at this stage. For drying the hydrogen gas, pass it through a drying tube packed with desiccant: gas generator -> rubber tubing -> bung with glass tube -> drying tube -> reaction vessel (see image for example). From what I understand, hydrogen gas and concentrated sulphuric acid shouldn’t react so bubbling it through is a good way to remove moisture.

Just to clear up a misconception, NaOH doesn’t act as a catalyst as it is consumed by the reaction, producing sodium aluminate and hydrogen. 2 NaOH + 2 Al + 2 H2O -> 2 NaAlO2 + 3 H2.

D4BA4DE3-9B9C-4666-B124-22D084FD7FD9.jpeg - 351kB

5Qr25Pla - 19-2-2018 at 09:02

thank you, that image was very helpful. and knowing that the sodium is used up in the reaction makes me wonder if it would be better to put more sodium.

@wg48 already mentioned that an addition funnel for adding more liquid/naoh mixture would let me add more liquid over time without letting other gases in. so i added an addition funnel to the apparatus. this should clear up the problem of gas production slowing down.

i couldnt get my hands on a copy. :( is it in the library this site has by chance? or someone else's maybe?

My main concern here is how reactive/volatile/powerful the reaction between the lithium and hydrogen when i increase the heat. knowing what the worst case scenario is would be very helpful. the amount to be processed is 1 gram or less.

the apparatus will be purged by produced hydrogen before any lithium is introduced to the reaction vessel. this should eliminate all possibility of flashback if something goes bad. potential pockets of oxygen/nitrogen/etc... will be eliminated in final build of apparatus.

other info: the heat is supplied by NiCr coil + blower + potentiometer + thermostat at end of blower to ensure heat doesnt exceed 392F/200C (supposed autoignition temperature of Lithium Hydride according to

Magpie - 19-2-2018 at 09:57

Leonid Lerner's book is available through the CRC publishing company. It has many valuable syntheses. I used one for making CCl4 from chloroform with nearly 100% yield.

If you read the experimental section on making LiH you will see that it is not trivial.

LearnedAmateur - 19-2-2018 at 10:29

Quote: Originally posted by 5Qr25Pla  
... knowing that the sodium is used up in the reaction makes me wonder if it would be better to put more sodium.

Your best bet would be to calculate how many moles of aluminium and sodium hydroxide you’ll need from the equation I provided, and then add another 5-10% to account for losses and the initial purge, as well as the aluminium oxide layer which won’t produce hydrogen. You shouldn’t need to figure it out for the water though, that should be in excess anyway as the solvent for the NaOH.

Just out of curiosity, what will be your source of Al? Powder? Turnings? Foil? That will have to go into your considerations for H2 yield, as the larger the surface area, the higher the proportion of Al2O3.

Bert - 19-2-2018 at 10:42


moisture seems to be the only danger in this experiment and i am confident that the moisture level is really low after the coil condenser already. this being said, would a more experienced person be brave enough to raise the temperature of the hydrogen to say 180C - 200C and attempt to react the hydrogen more quickly/efficiently?

You have a bit more than moisture to worry about here. Hydrogen is an escape artist, with a wide range of explosive mixture in air.

Handling the ammount of Hydrogen required to synthesize a moderate quantity will quickly show just how good your planning and technique (particularly safety) are-

The strong base, strong acid and flammable reactive alkali metal/whatever product has formed may well come out and join the party too, after a Hydrogen explosion.

5Qr25Pla - 19-2-2018 at 13:54

my aluminum is in the form of whole melted but coarse on the ouside chunks. these were produced by melting aluminum from other sources and then heated extremely hot till brittle then poured into crude "ingots". these ingots float in my liquid well and produce a lot of hydrogen for quite a while (one ingot produces a flow of hydrogen for about an hour) the length of time of reactivity is adjusted by the surface condition of the aluminum and the density. smoother/denser aluminum "ingots" react slower at first due to the smooth edge and then react longer due to density. the much less dense aluminum chunks are very rough and react very quickly and vigorously. these react for the first 10-15-30 minutes while also making the water very warm. this purges the system and gradually as the water warms it activates the activity of the other, more dense chunks of aluminum which then carry the reaction to completion. (about 2-3.5 hours as prep-chem states that 2 hour residence time is more than is needed at 125C)

In the post titled: "lithium hydride synthesis" the user @JJay says that "Small Scale Synthesis of Laboratory Chemicals suggests heating.... 700C". Is heating lithium to 700C really necessary to ANY degree?. suggests that this exact reaction will proceed "at temperatures as low as 29C" with a 60% yield at 99C and an 85% yield at 125C. to me. it seems like no more than 150-250C is necessary.

the main factor contributing to difficulty of producing the hydride is the surface condition of the lithium. if this is the biggest problem to overcome couldn't one potientially just scratch the surface of the lithium while in a hydrogen/argon atmosphere and then start the reaction without ever letting oxygen/nitrogen into the picture?

Worst case scenario, the melting point of lithium is ~180C. The melting point of LiOH is 462C. This "could" be bad in certain circumstances where the lithium is protected by the N/O/x layer, keeping it from reacting. But wouldnt the lithium just melt away from the O/N/x layer and then the lithium would make LiH and the LiOH would make MINUTE amounts of H2O which would then partially react with the lithium again and partially would exit via the exhaust. Eventually the OH would be almost entirely removed, giving way to the purer/smoother production of LiH.

If there IS an explosion it should start at the lithium reaction chamber and vent through the exhaust possibly leaving a burning flame of hydrogen (which could be avoided by simply burning the exhaust anyway)

The explosion produced by 90% Hydrogen 10% Oxygen (worst case scenario. Less than 1% oxygen is expected) doesnt seem to produce much force. This sounds crazy. But in a glass bottle it did not burst the bottle upon ignition. I am wondering if ignition happened would maybe good glassware handle the ignition? Im thinking some probably could handle it easily. Once ignition happens the spare o2 would be used up immediately and the rest of the reaction could be considered "safe" (unless there are ungodly amounts of LiOH in the reaction chamber. But again, im only using 1 gram for analytical (and practical) purposes.

The exhaust port is larger than the intake port of the reaction chamber encouraging expansion in the direction of the exhaust.

The entire apparatus is completely sealed before start-up using vacuum grease for ground glass adapters and is placed outside of the lab to avoid hydrogen buildup. The reactor is also outside. all tubing/adapters are also sealed. the heat of the lithium reaction vessel is kept AWAY from the hydrogen production vessel and there is a spiral tube between the two vessels to create further friction and reduce momentum in the direction away from the lithium and towards the Al/Naoh/H2O mixture (so as to hopefully avoid bursting if explosions of any size happen)

the hydrogen production vessel is controlled and tended to by another "hobby technician" so that complete focus can be had on the subject of heating the hydrogen "safely" below its autoignition temperature of 500C and ensuring that Hydrogen leaks ARE NOT HAPPENING.

I am wondering what the likelyhood of autoignition of hydrogen is in a "pure" and sealed environment. i am thinking that if the apparatus is sealed properly the chance for autoignition is essentially 0% (but probably more realistically like 0-5% considering the possible ignition of pockets of produced H2O [from LiOH + LiH ---> Li + H2O?])

I am also wondering about how exothermic this reaction might be. is there a risk of it heating to above 250C on its own somehow?

[Edited on 19-2-2018 by 5Qr25Pla]

Bert - 19-2-2018 at 14:48


The explosion produced by 90% Hydrogen 10% Oxygen (worst case scenario. Less than 1% oxygen is expected) doesnt seem to produce much force. This sounds crazy. But in a glass bottle it did not burst the bottle upon ignition.

How did you come up with this as worst case? You are not using O2, but air for an environment.

20180219_161253.png - 116kB

5Qr25Pla - 19-2-2018 at 17:31

Quote: Originally posted by Bert  


The explosion produced by 90% Hydrogen 10% Oxygen (worst case scenario. Less than 1% oxygen is expected) doesnt seem to produce much force. This sounds crazy. But in a glass bottle it did not burst the bottle upon ignition.

How did you come up with this as worst case? You are not using O2, but air for an environment.

i dont think i have been clear enough :( i am sorry. let me clarify.

the ENTIRE apparatus (including lithium reaction chamber, exhuast and heating tube) is PURGED with hydrogen or argon (hydrogen in my current case) prior to initiation. when the apparatus has been purged with (roughly 3 litres @ 1atmosphere) enough hydrogen/argon then the lithium is placed in the reaction vessel with the hydrogen still running. when the lithium is in the reaction vessel another 0.5 - 1.0 litres of hydrogen are used to purge the (TINY) reaction vessel. once the lithium has been introduced and the hydrogen has purged the system, then and ONLY then is heating to begin. the heating is done by the hydrogen itself so as to avoid hotspots on the lithium and to increase the reactivity of the hydrogen.

the picture that you @Bert provided was useful to me though. if the vessels have been purged properly (and there are no air pockets available for other gases to dwell in) then there should be relatively no risk of fire/explosion during NORMAL operation (ASSUMING NO LiOH/Lixx is present. but. as there will almost for sure be LiOH/Lixx present there is still the very small chance that the reaction produced between the Li, Lixxx, LiH, H2, and any produced gases could create small, localized, explosions.

these "explosions" should be relatively harmless actually as long as the Lixx % is kept very low (preferably at < 0.05 grams total impurity or less) and the reaction is kept slow/low temp.

the reaction doesnt need to yield %100. and even at room temperature the yield should be "enough"

the added heating is PRIMARILY used to greatly reduce the reaction time (allowing the reaction to complete before the hydrogen stops being produced) but making the yield a higher percentage is also a very nice benefit. this will also help to keep the LiH from getting trapped in unreacted lithium.

i have ran the apparatus with very slight success. but with no heating. i am afraid that when the reaction really gets going it will be unstoppable due to the heat that it generates. a good example of a reaction that gets going and then heats itself and continues to heat itself is the reaction of methanol over a red-hot catalyst. the methanol goes over the catalyst and then reacts with minute levels of oxygen and produces formaldehyde. the reaction is so hot that it will sustain itself as long as the gases are pushed across the catalyst. if this happens with my LiH reaction that is fine. but i dont want my reaction to superheat itself to above about 200C. i want to stay as close to the bare minimum total energy as possible.

5Qr25Pla - 20-2-2018 at 08:53

in this post: the user @HNO3 states that the "lithium 'wets' the steel crucible" and that it "forms a hard, less reactive chunck that" he could not remove after melting. is there any reason my lithium should "weld" itself to my stainless steel to any unremovable degree? i expect some to be stuck to the bottom. but my guess is that the majority should come up quite easily. (just considering how soft lithium is)

... here's a pdf for anyone interested.

[Edited on 20-2-2018 by 5Qr25Pla]

Attachment: US2408748.pdf (844kB)
This file has been downloaded 275 times

5Qr25Pla - 20-2-2018 at 09:23

it is not required but mixing the hydrogen with inert gas such as helium or argon (i will use helium) will reduce the heat produced by the apparantly very exothermic reaction. this solves my problem of possible overheating of my reaction apparatus (stainless steel, but thin)

i will run the helium first through an inlet tube in my hydrogen production flask (so as to ensure homogeniety) and then heat my reaction chamber, then after it is heated to 180-220C i will gradually introduce higher and higher levels of hydrogen until the reaction is either self sustaining or "stable" enough to run to completion.

i am still looking for improvements though.

improvements to be made:

further (potentially unnessecary) drying of the hydrogen/helium gases

removal of very minute levels of air that could/will be released from the water/aluminum reaction liquid (not a huge concern either as the water can be pretreated to "remove/liberate" the air that has been dissolved in it before initiation"

this entire apparatus is actually quite simple and cheap. and so far, all things required are easy to aquire. i hope to keep it that way. eventually i hope to document the entire process in a very detailed manner so that others can produce hydrides. it is well understood that this process is dangerous and is not for everyone, but there are those (myself included) that would love to benefit from this that can and will exercise safety and caution.

Corrosive Joeseph - 22-2-2018 at 10:03

Quote: Originally posted by Magpie  
"Small-Scale Synthesis of Laboratory Reagents" by Leonid Lerner


[EDIT] - The link is now fixed. File too big for upload

[Edited on 22-2-2018 by Corrosive Joeseph]

Bert - 22-2-2018 at 10:32

Non functioning link.

Copyrighted work by a member.

Book costs about US $170 to buy.

happyfooddance - 22-2-2018 at 10:34

Everytime I see Magpie's sig, "The single most important condition for a successful synthesis is good mixing - Nicodem", I think of len1's disgraceful failure and the subsequent arrogant attacks on Pok, and others, in the potassium sticky thread... I know you miss him, Mag, but I don't. :)

Magpie - 22-2-2018 at 10:48

Yes, len1 really messed up there and got egg on his face. He owes Pok an apology. Nonetheless, his book is wonderful. There's nothing else like it for the home chemist. Also, his contributions to Prepublication are magnificent.

He can be quite testy, however.

happyfooddance - 22-2-2018 at 11:11

I agree, his contributions are more than most. But in the spirit of this forum I see YOU as a much more valuable contributor. Plus, he got what he wanted from this forum and still collects the royalties. Also, he got many eggs on his face, that was just the one that I am always reminded of when I see your sig.

He never got "experimenter of the year"!

Edit: Also, he did apologize to Pok, it went something like, "I am still right for making the assumption I made, and you were wrong for not giving enough clear, scientific data..." Even though pok clearly outlined his procedure and said, "Do it like this and see what happens..." When he followed Pok's procedure, Potassium.

[Edited on 2-22-2018 by happyfooddance]

[Edited on 2-22-2018 by happyfooddance]

S.C. Wack - 22-2-2018 at 14:18

He said here he got a flat fee and isn't worried about copyright that isn't his. The link works without the s on the http.

The lowest temperature reactions seem to be not simple and straightforward. The Chinese make an interesting statement about temperatures around the mp.: "The hydrogenation rate increased with the raise of temperature at the beginning and reached a peak value at about 190C. Then the rate decreased and almost no hydrogen absorption occurred in the range of 280-480C. The hydrogenation rate increased again when the temperature was higher than 500C and achieved a maximum at about 665C. It was found that the optimal temperature range for hydrogenation of lithium was between 665 to 700C and with the pressure ranged from 50 to 55 kPa."

What happens when one proceeds with Li dispersion in mineral oil under NaH synthesis conditions?

Corrosive Joeseph - 22-2-2018 at 14:21

Quote: Originally posted by Bert  
Non functioning link.

Copyrighted work by a member.

Book costs about US $170 to buy.

The link is now fixed.

I am a great fan of Len1's work, but as far as I am aware, he has NO rights to that book. They were all signed over to the publisher.

It was a labour of love and now we have it.
(And so we should, there are even a cluster of chapters in PrePub)

Also,there are a number of threads here about the book and there already is a link in References forum.




[EDIT] - Post above was posted while I was writing this

[EDIT2] - Stupid grammar

[Edited on 22-2-2018 by Corrosive Joeseph]

[Edited on 22-2-2018 by Corrosive Joeseph]

happyfooddance - 22-2-2018 at 17:19

I might just be really slow, but I have spent a good bit of time and still haven't been able to see even a single page of that book. I am sure it is good, because you say so!

happyfooddance - 22-2-2018 at 19:04

Quote: Originally posted by Corrosive Joeseph  

I am a great fan of Len1's work, but as far as I am aware, he has NO rights to that book. They were all signed over to the publisher.

It was a labour of love and now we have it.
(And so we should, there are even a cluster of chapters in PrePub)

Also,there are a number of threads here about the book and there already is a link in References forum.

I do appreciate len1's work. I have followed this forum for years, I learned chemistry from this forum! I didn't know that his book was accessible here, I had only seen it "advertised" here. I don't mean to deprecate a long-time and valuable member, my apologies.

Bert - 23-2-2018 at 14:42

Somehow I missed whatever controversy happened. Before I was a moderator?

happyfooddance - 23-2-2018 at 15:50

Quote: Originally posted by Bert  
Somehow I missed whatever controversy happened. Before I was a moderator?

I am sure I was making a mountain out of a mole-hill. Len1 (and2) was a great contributor and his book is indeed excellent.

Magpie - 23-2-2018 at 18:41

Quote: Originally posted by Bert  
Somehow I missed whatever controversy happened. Before I was a moderator?

Pok showed us how to make potassium from KOH and a tertiary alcohol, IIRC. Len1 claimed Pok's work was bogus, when it clearly was not: We were shown pictures of big balls of K. So, a protracted argument ensued. Pok, of course, was right. Len1 bowed out of the argument. Pathetic for a man of his accomplishments and high stature. I guess we all get one mistake. His fault was in not admitting this graciously.

5Qr25Pla - 24-2-2018 at 16:24

thank you for the ebook.

i am going to try to run the system again with the included adjustments. im not sure if that will be today/tomorrow or when yet but it will be soon. i need to get my hands on some pure helium. otherwise ill have to use argon. but i am hoping the gas supply business near me has pure enough helium.

5Qr25Pla - 3-3-2018 at 08:18

I have not abandoned this thread. i am still trying to gather materials. i need stainless steel and havnt had the opportunity to buy any yet. a quartz reactor would be nice too. but i highly doubt ill come across one in the near future. but that's okay. the stainless should do great.

my last reactor did not handle the heat. i ran the whole process (without the lithium but with everything else) and i heated my reactor and it could only stand a temperature of about 400C (nipples connecting to inlet and outlet hoses were too hot/melted rubber hoses)

my last reactor also relied on the seal of pressed metal. as the metal was heated/cooled, the seal expanded/contracted making tiny escape holes for hydrogen.

i tested various peices of stainless tubing that i had and found that if i heated the lower portion of a 200-300mm tube that the higher portion seemed to stay cool enough for my seal and hoses to remain intact. i just need to get better materials and i will try again.


5Qr25Pla - 22-4-2018 at 12:41

When I began this effort, I assumed I would be able to reliably produced enough hydrogen and dry it enough at the same time to use the hydrogen as it was being produced for the reaction. This quickly has proven to be a bad idea. The Hydrogen must first be produced using any means necessary as long as you only form hydrogen. And then it must be dried and compressed for use.

I will now detail the new method and improvements

Step One - Hydrogen Production (Aluminium/NaOH/H2O method)

a five gallon bucket with a bag of aluminium balls/foil/other sealed to the side of it was fitted with a lid that had a distill head and condenser sealed into it.

the condenser lead to a water trap and then was lead to an (optional) vertical coil condenser that was cooled with the coolest ice water (to remove more water. but this second condenser only catches a few drops or so.

after the final water trap there was a vacuum take-off adapter that was lead into the intake of a compressor and that compressor was set to fill at the rate of production. (a large heavy duty balloon or bag was used with a switch to do this)

the whole system including the bag of aluminum is purged with argon or hydrogen (hydrogen greatly preffered for purity)

Step Two - Drying the Hydrogen (sulfuric acid method)

the first compressor with the "wet" hydrogen was srayed through a very tall 1 liter graduated cylinder that was filled full with broken glass to break up bubbles.

these bubbles took up a lot of volume so the rate was rather slow. but the slow rate ensured that the acid could strip any moisture.

the acid used was very cold but was NOT allowed to absorb atmospheric moisture. the acid was cooled AFTER being charged into the cylinder.

the exhaust/dried hydrogen was then charged into a second compressor/tank

(there will be some contamination in the hydrogen after the first run due to the air that was already in the tanks. the first run should be used to purge the system. the second run can be consider pure IF there were no leaks and you were careful. but the first tanks with hydrogen will NOT be pure and WILL NOT be useful for this reaction)

this may sound like a lot of work. but i was able to run this reaction twice in one hour.

one run purged my compressors of old air and moisture. and another run gave me pure (mostly dry) hydrogen.

there will almost positively be a LITTLE moisture left in the second tank of hydrogen. that being said. it will be in anyone's best interest to dry the hydrogen AGAIN between the tank valve and lithium reaction zone.

if you only have one compressor/tank it is completely fine to use only one (assuming you are going to dry the hydrogen after the tank and before the lithium reaction zone)

being able to have a higher flow of hydrogen through your drying acid (or other drying agent) will be to your advantage. the lithium absorbs hydrogen fairly quickly and you dont want to risk it absorbing more hydrogen than you can provide. this might not be a problem. but then again. it might be. i wouldnt want to find out the hard way.

[Edited on 22-4-2018 by 5Qr25Pla]

5Qr25Pla - 22-4-2018 at 14:44

now the hydrogen is made. it has been dried. and is stored in a tank at whatever psi you like. mine is at ~120 psi and i have a 3-5 gallon tank (guessing by size. its an old air compressor and tank for cars)

next is to prepare a vessel for the reaction. these are the parts i used.

2 - 304/316 Stainless Steel Cap 1 inch
1 - 304/316 Stainless Steel Nipple 1 inch(d) x 8 - 12 inch long (i prefer longer for "safety")
2 - 304/316 Stainless Steel Nipple 1/4 inch x 6 inch
2 - 1/4 to 1/8 reducers
2 - 5 - 10 feet 1/8 stainless steel pipe/tubing
1 - 1/4 stainless steel threader (make sure its the right size for your nipples!!)
1 - 1/4 drillbit for drilling holes through one cap for nipples
(1x8 inch nipple and 1 stainless steel cap is all that has to be stainless. others dont have to be if you cant afford it)

(all of these items were ordered on the internet at the same website. and are easy to find anywhere and even are sold locally in most towns)

one of the caps had two holes drilled in it @ 1/4 inch diameter. these holes were tapped/threaded and fitted with the 2 - 1/4 x 6 nipples. these nipples were screwed in super tight to create a seal and will never be removed. if you can weld. weld them in to prevent leaks.

the 2 - 1/4 x 6 nipples were fitted with the reducers and then the 5 - 10 foot tubes were fitted in the reducers

these tubes are the inlet and outlet of our reactor this is screwed onto the 1inch by 8-12 inch nipple so tight that it seals and ruins the threads. again. weld this if you can. its so much better. but if you cant. just make sure there is ZERO leak. this is VERY difficult to do without welding. and traditional tape/dope wont work as it gets too hot.

the bottom is now left open. you are left with one cap. the apparatus looks like this.

1/8 tubing/inlet.............1/8 tubing/outlet
===========|| ||=================
..........................|||| - 1/4 x 6 nipples
.........................[ ] - cap
..........................| |
..........................| | - 1inch x 8-12 inch nipple/tube/chamber
..........................| |

the other cap is not yet on because it hasnt been charged yet. we will put the other cap on after the lithium is placed inside and then we will tighten that cap to seal it too.

[Edited on 22-4-2018 by 5Qr25Pla]

[Edited on 22-4-2018 by 5Qr25Pla]

The Verdict

5Qr25Pla - 22-4-2018 at 16:18

okay. the hydrogen is ready and waiting. and our (hopefully sealed very very well because if its not thats gonna be really bad) reactor is mostly assembled and ready to go. now on to the actual reaction.


before we begin we should be sure that we are ready to either store or dispose of the product. the product lithium hydride will be in lump metallic form. it will be stuck to the insides of the apparatus and it will be difficult to remove without a drill or mill or something. a hammer and chisel will work. but be aware that the product is dangerous and CAN ignite if care is not taken.

the hydride is mostly safe in the air and as long as one is careful it can be removed without any inert atmosphere or special solvents.

do NOT allow moisture to come into contact with the hydride.

the reaction has three main parts

1. the hydrogen is released from its storage tank
2. the hydrogen is dried over very cold sulfuric acid or better drying agent
3. the hydrogen is reacted with the lithium in the final reactor

the lithium reactor (1inch x 8-12 inch nipple/pipe) is filled with up to 10 grams of lithium (i used 3 grams and it seemed to be a small amount that was hard to get out as most of it coated the walls. more would likely pool up easier)

the other cap from before is placed on the end of the pipe and tighted to the extreme. (when you close up the exhaust and spray hydrogen in there should be ZERO leaks. ZERO)

leaks can fairly safely be found with a flame. if there is a dangerous amount of leakage a flame will be present. if there is a flame. just turn off the hydrogen. allow to cool. and tighten again.

once the reactor is sealed and the lithium is inside be sure that the drying cylinder and all connections are good. then purge the system with hydrogen to remove air.

after purging the system and you are sure there is no more air you may begin heating the lithium reactor.

heat the reactor slowly to between 700C and750C (the book by Len1 suggested 730C)

at this temperature the lithium AND the lithium hydride are both liquids and the reaction goes pretty easy. as long as the temperature is accurately measured and hydrogen flow is adequate about 4-8 grams per hour can be converted to the hydride.

the lithium hydride will form blobs on top of the lithium that will sink to the bottom and expose more lithium. eventually (rather quickly) all of the lithium is converted and hydrogen absorbtion stops.

once hydrogen absorbtion stops allow the reactor to cool completely while under hydrogen still (doesnt take long. few minutes tops)

once cooled you may disassemble your device and retrieve the hydride. unscrewing the bottom cap to get to the hydride was the route i took. but this was VERY difficult. its worthwhile. but if you want to make larger amounts i would recommend coming up with a method to quickly get the cap off. the lithium melts and "welds" to the inside of the cap and tube making removal of the cap very difficult and i even admit that i was tempted to just cut the end off. but i didnt. after much work i got the cap off.

lithium WILL eventually make its way through the metal and the threads on the cap. but this never happened to me. i wouldnt run this reaction for longer than an hour or two. just to be safe. another good idea would be to put the reactor in another steel tube just in case lithium leaks. but as long as you have good ventilation the leaking lithium shouldnt be too big of a worry. it will come out very slowly. just stop the reaction if it does.

about 4 hours of work and about 3 or 4 grams of lithium yielded about 3 grams of lithium hydride. there was more hydride stuck inside that i left there and couldnt easily remove.

any impurities from the oxidation/nitration of the lithium were negligable and did not seem to hurt the yield to any noticable degree.

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Ubya - 23-4-2018 at 05:09

nice setup, i just have a safety complain, to detect hydrogen leaks is enough some soapy water in a spray bottle, lighting any leaks could be dangerous if the system is not compleatly purged.
nice job for your system!
regarding the stuck bottom pipe cap after the completed reaction you could try to make a custom reaction chamber and using another way to close it,, like a pressure clamp or something else, threads can get filled with lithium hydride and as you experienced be a pain to separate

symboom - 23-4-2018 at 09:45

Nurdrage has a solution for that using a smoke detector
This can detect hydrogen gas
Detect Hydrogen with a Carbon Monoxide Detector

A c clamp to hold the appetatus closed also
Congradulations you are the first to make lithium hydride using home chemistry improvisation

[Edited on 23-4-2018 by symboom]

symboom - 17-8-2018 at 19:29

Video of synthesis of lithium hydride
Its a good use for a ballon

[Edited on 18-8-2018 by symboom]

[Edited on 18-8-2018 by symboom]