Sciencemadness Discussion Board

Solubility of calcium nitrate in methanol

C6(NO2)5CH2CH(CH3)N(NO2)2 - 7-3-2019 at 15:39

This source was linked from wikipedia:
http://chemister.ru/Database/properties-en.php?dbid=1&id...

I found this online:
https://onlinelibrary.wiley.com/doi/abs/10.1002/%28SICI%2910...
Quote:
Fibroin dissolves in 75% w/v Ca(NO3)2/MeOH solution at a temperature of 67°C


So can 100gm of methanol really dissolve 134 or more gm of Ca(NO3)2?

If it's for real, you could use it to extract calcium nitrate from just about anything, or possibly use it as a propellant or explosive (the ratio of methanol to oxidizer is better than methanol in air at the flammable limit, and a 3:1 mixture would be only slightly fuel rich) or else you could soak e.g. a string in calcium nitrate-methanol solution and (if it doesn't absorb too much humidity) you have a fuse.

So, has anyone really tried to make a saturated solution of calcium nitrate (not the ammonium double salt, pure Ca(NO3)2)? was it really so soluble?

Thanks.

RogueRose - 7-3-2019 at 17:13

Yes, it does dissolve very close to those amounts of Cal nitrate. I have about 1L of the solution which I tested to see if it would work some time ago. The solution ends up being a slightly yellowish solution even though the same nitrate makes a clear solution in water.

I've never extracted the methanol from the solution. My plan was to do this and try to purify the nitrate to see if there was anything else in it besides the stated pure Ca(NO3)2.

TheMrbunGee - 8-3-2019 at 05:14

Quote: Originally posted by C6(NO2)5CH2CH(CH3)N(NO2)2  

So can 100gm of methanol really dissolve 134 or more gm of Ca(NO3)2?

If it's for real, you could use it to extract calcium nitrate from just about anything, or possibly use it as a propellant or explosive (the ratio of methanol to oxidizer is better than methanol in air at the flammable limit, and a 3:1 mixture would be only slightly fuel rich) or else you could soak e.g. a string in calcium nitrate-methanol solution and (if it doesn't absorb too much humidity) you have a fuse.

So, has anyone really tried to make a saturated solution of calcium nitrate (not the ammonium double salt, pure Ca(NO3)2)? was it really so soluble?

Thanks.



I believe the reference is for anhydrous Ca(NO3)2, solubility will change for tetrahydrate. Being crystal hydrate, for pyrotechnic purposes it will not work well, It is also quite hygroscopic. Your fuse theory might not work, the fuses might never dry (in normal room temp. and humidity), and might be hard to light and unreliable. But, it is easy to do, so worth giving a shot!

As a propellant or explosive? You mean solution of salt in the meOH? If so - there will be problems with low BP of meOH and high decomposition t° of nitrate. ( 65°C vs 500+°C)

C6(NO2)5CH2CH(CH3)N(NO2)2 - 21-3-2019 at 13:19

Thanks for the replies. Sorry I couldn't get back on here sooner. I am amazed that calcium nitrate really does have such a high solubility in methanol.

As far as using it as a propellant or explosive, I don't know if that would work as well as I was imagining. Besides the fact that methanol would evaporate before it would react with calcium nitrate (something which wouldn't happen if it were initiated with heat and violent shock simultaneously e.g. with a blasting cap), a mixture of 43% methanol to 57% calcium nitrate (by weight) is going to be very fuel rich. According to one source, a mixture of 35% tetranitromethane and 65% methyl alcohol is just barely detonatable.
https://link.springer.com/article/10.1134/S0010508212030148
A kilogram of such a mixture would contain 1.785mol of TNM, capable of fully oxidizing 3.57mol of methyl alcohol within the mixture. Also, a mol of TNM decomposing creates CO2, and almost as much energy as a mol of methyl alcohol burning. So the total energy release in a kilogram of the mixture should be akin to 5.36mol of methyl alcohol burning.

570 grams of calcium nitrate (dissolved in 430 grams methyl alcohol) would have enough oxygen to burn 5.79 mol of methyl alcohol. But it takes energy to decompose calcium nitrate, as opposed to tetranitromethane which is an explosive in and of itself. Also, whereas all of the decomposition products of the TNM mixture (including fuel rich compounds like CH2O, H2, CO, etc) are gaseous or at least volatile, some of the decomposition products of the calcium mixture would be nonvolatile solids like Ca(OH)2. So I think chances are that a saturated solution of calcium nitrate in methanol at room temperature could not be detonated, or else would be very hard to detonate. I guess that's good news for RogueRose, seeing how he has a liter of it in his lab.

The 3:1 solution might still work, but there is very little use in an explosive which only says mixed when heated to its boiling point. That would be really inconvenient and generally unsafe. Soaking fuses in it and then drying might still work, but it does absorb humidity. If/when I get some Ca(NO3)2, I will try it. Again, thanks for all your great replies.

[Edited on 21-3-2019 by C6(NO2)5CH2CH(CH3)N(NO2)2]

happyfooddance - 21-3-2019 at 13:29

Not really that important but I think you would get CaO + H2O as the initial decomposition product, which is an extra mol of gas at those temps.

C6(NO2)5CH2CH(CH3)N(NO2)2 - 21-3-2019 at 13:48

Excellent point. Still a fair bit of dead weight, with ~20% of the reaction product's mass being solid in that case.

Anan'in et.al. used a booster of TNT 6cm in diameter and an unspecified length (probably longer than wide). But there is still a chance it would work in a large enough charge. Stranger things have happened.

happyfooddance - 21-3-2019 at 14:43

Quote: Originally posted by C6(NO2)5CH2CH(CH3)N(NO2)2  
Excellent point. Still a fair bit of dead weight, with ~20% of the reaction product's mass being solid in that case.


Yeah, but a detonation is a detonation. Have you ever seen CuO+Al thermite go off? What about those reaction products? So I would just be concerned about whether it would detonate at all, not whether I lose one eye or two... Just my 2 cents!

Deathunter88 - 21-3-2019 at 17:08

Quote: Originally posted by happyfooddance  
Quote: Originally posted by C6(NO2)5CH2CH(CH3)N(NO2)2  
Excellent point. Still a fair bit of dead weight, with ~20% of the reaction product's mass being solid in that case.


Yeah, but a detonation is a detonation. Have you ever seen CuO+Al thermite go off? What about those reaction products? So I would just be concerned about whether it would detonate at all, not whether I lose one eye or two... Just my 2 cents!


I don't think think the reaction between CuO and Al can be considered a detonation though, as there is no supersonic shockwave propagated through the material.

happyfooddance - 21-3-2019 at 19:35

Quote: Originally posted by Deathunter88  
Quote: Originally posted by happyfooddance  
Quote: Originally posted by C6(NO2)5CH2CH(CH3)N(NO2)2  
Excellent point. Still a fair bit of dead weight, with ~20% of the reaction product's mass being solid in that case.


Yeah, but a detonation is a detonation. Have you ever seen CuO+Al thermite go off? What about those reaction products? So I would just be concerned about whether it would detonate at all, not whether I lose one eye or two... Just my 2 cents!


I don't think think the reaction between CuO and Al can be considered a detonation though, as there is no supersonic shockwave propagated through the material.


Exactly, that's a part of the point I was trying to make. If a non-detonation with solid end products can be so energetic, I wouldn't be worried about whether a mixture that detonates has 20 vs any other percentage of solid end products.