Nitric acid and hydrogen peroxide - storage in freezing temperatures

[orvi]

Hi guys
I tried to find the info myself, but Googling did not bring any meaningful info about my dilemma. And in the tables/books, I also did not found any info.

I have two HDPE canisters, one with 65% nitric, second with 30-35% hydrogen peroxide. I store them in a building that is protected from elements, but has no heating. I am afraid that when winter hits, and temperatures drop below -25 °C (could be in my location), they will freeze. I wouldn´t mind that, because like 99% of all substances act predictably and have higher densities as solids, than as liquids. But I want to be sure that any accidental freezing won´t rupture the canisters. I have them placed inside another cut canisters, acting like a catchpan, just in case... But

Question is - do anybody know how would 65 % nitric and 30% hydrogen peroxide act upon freezing ? Do they increase density as solids, or act as water (which expands upon freezing).

All I could find is that as pure substances, both act regularly and increase density upon freezing. But I cannot find any data regarding water solutions. All I know that nitric will likely freeze partially at like -18 to -26 °C, and hydrogen peroxide at -25 °C.
Placing them somewhere else would be difficult at the moment, but if the situation require action, I will need to deal with it. However, if there is nothing to worry about, I would be glad to hear it

Thank you for your input
orvi

 

[Ultrax]

See a diagram for the HNO3*H20 state. Sorry, Russian language only. I hope translation shouldn't be a problem

 

[Ultrax]

Extrapolate the expansion of solutions based on the volume fraction of water.

 

[Ultrax]

Diagram of the state of the hydrogen peroxide (H2O2) - water (H2O)system.

 

[4metals]

With a boiling point of around 83°C and a freezing point of -42°C, Nitric Acid 65% is suitable for a range of laboratory and industrial applications.

Alliance Chemical

Refrigerating or freezing hydrogen peroxide is a way of preserving hydrogen peroxide.

It is not possible for a 35% food-grade hydrogen peroxide to freeze in a normal freezer. This is because it freezes at -34°C, whereas the range of the average home freezer is between 0°C and -17.78°C.

Refining in an unheated building has many challenges! Apparently freezing of your nitric and peroxide are not one of them.

Bulkperoxide.com

 

[orvi]

Thank you guys. I thought about it and maybe I am just overly concerned. I looked these freezing diagrams beforehand, but they did not provide any info about density difference when phase change happens.
But well, it simply may not happen at all, as inside the building, it usually isn´t as cold as outside (concrete floor transfer some heat from the ground).

With a boiling point of around 83°C and a freezing point of -42°C, Nitric Acid 65% is suitable for a range of laboratory and industrial applications.

Alliance Chemical

Refrigerating or freezing hydrogen peroxide is a way of preserving hydrogen peroxide.

It is not possible for a 35% food-grade hydrogen peroxide to freeze in a normal freezer. This is because it freezes at -34°C, whereas the range of the average home freezer is between 0°C and -17.78°C.

Refining in an unheated building has many challenges! Apparently freezing of your nitric and peroxide are not one of them.

Bulkperoxide.com

I do not refine there, I just have my stuff stored, because my refining is now halted for more than half a year after my partner passed away. As organic chemist, I know that freezing chemicals is usually best way of preserving them, but I just have some doubts about this specific case.
Maybe I try some small experiment in a lab to determine if I would be able to crack a glass vial filled with nitric or peroxide, if I freeze them with liquid nitrogen

 

[Ultrax]

I looked these freezing diagrams beforehand, but they did not provide any info about density difference when phase change happens.
But well, it simply may not happen at all, as inside the building, it usually isn´t as cold as outside (concrete floor transfer some heat from the ground).

This happens precisely at the solid water points on each diagram. Extrapolate the expansion of solutions based on the volume fraction of water. The density of water is 1.00, the density of ice in solution is 0.91. After freezing, the volume of water in the solution increases by 9%.

Peroxide and nitric acid molecules do not expand when frozen. They compress (and very little), so this can be neglected in volume measuring for HDPE vessels.

Just recalculate the mass fraction of frozen water and linearly change the total volume.

Or simply leave 10% of the volume of each filled vessel empty for any concentration.

 

[orvi]

This happens precisely at the solid water points on each diagram. Extrapolate the expansion of solutions based on the volume fraction of water. The density of water is 1.00, the density of ice in solution is 0.91. After freezing, the volume of water in the solution increases by 9%.

Peroxide and nitric acid molecules do not expand when frozen. They compress (and very little), so this can be neglected in volume measuring for HDPE vessels.

Just recalculate the mass fraction of frozen water and linearly change the total volume.

Or simply leave 10% of the volume of each filled vessel empty for any concentration.

This is an interesting approach to solve this, however I do not feel this assumption would work there because of formation of distinct hydrate species, stated in literature (HNO3.H2O and HNO3.3H2O).

Usually, when distinct hydrate or solvate can form in the system, it forms and thus remove the precise ratio of the components to the solid phase. What is left is the key But most of the times, onset of the freezing is depicted on the freezing point curve, and further freezing can occur at this temperature, or at lower temperatures - due to the fact that fast-freezing hydrate crystallize out first.

I have the vessels only like 70% full (both) so I do not feel worried by this lack of space inside. But I experienced some ruptures of canisters which weren´t even half full. The biggest issue here is that water freeze at 0 °C - meaning plastics like PP or HDPE are relatively flexible even at this temperature. But when we slowly come down to like -20 °C and start some expansion in these canisters, they are much less flexible and rupture is more likely.

 

[orvi]

Eureka
I was finally able to find something relevant. Two distinct hydrates of nitric acid are known - mono and trihydrate. And I was able to find articles where guys issued their crystal structure. When you have X-ray, you have density

So, nitric acid monohydrate (78 wt% nitric, freezing point -37,6 °C) has density of 1,779 g/ml at -48 °C.
And nitric acid trihydrate (58,8 wt% nitric, freezing point -18,5 °C) has density of 1,621 g/ml at -188 °C.

Latter value is not very informative since from -188 °C to -18,5 °C, solid would expand, and the actual density at freezing point of this mixture would be higher... But at least I now know, that aqueous nitric in issued concentrations isn´t behaving like water, and contract upon freezing, like any other decent chemical

 

[orvi]

With 30-35 % hydrogen peroxide, it is less favourable "freezing situation", since distinct hydrates do not form until it reach like -52 °C and freezing seems (according to limited information I was able to source) to be equilibrium process, when solid ice precipitates from the solution, leaving enriched peroxide in it to the temperature of like -52 °C, when it completely solidify. One distinct hydrate, H2O2.2H2O is reported to exist, which has density of 1,36 g/ml at -190 °C (also not very informative number for our purposes).

Good thing to know is that ice formation from actual onset of freezing is gradual and not sudden. Meaning that regular 30 % stuff will start to freeze somewhere around -25 °C and continue to freeze to the -52 °C, when it all completely solidify. I doubt it would be linear, but -25 °C in my scenario is unlikely, and even if it gets below -25 in the winter, gradual freezing is not that problematic regarding solidified fraction is minor to the overall volume of leftover liquid.

 

[Ultrax]

This is an interesting approach to solve this, however I do not feel this assumption would work there because of formation of distinct hydrate species, stated in literature (HNO3.H2O and HNO3.3H2O).

This is not an assumption.
Hydrates, clathrates, suspensions, emulsions, true solutions containing water - everything corresponds to these calculations when water molecules pass into the solid phase.
This is due to the fact that water molecules are practically incompressible in any liquid system.

You can easily verify this experimentally in a couple of hours

As for ruptures of HDPE vessels filled to 70%, the problem is much more often associated with the quality of processing of their internal surface and insufficient wall thickness.

 

[Ultrax]

"Crystals were grown by cooling equimolar aqueous solutions of nitric acid sealed in glass capillaries
(m.p. -36.0°C). The intensities and cell dimensions were measured with a Stoe-Philips semi-automatic
two-circle diffractometer (Cu K~, Ni-filtered, moving crystal-moving detector scan technique) modified for low-temperature studies. Measurements were obtained at 85 and 225 K from two cylindrical crystals (diameter 0.10 mm, length 0"30 mm) mounted about a and c respectively. "
--------------------------
It seems to me that this data from the both .pdf articles mentioned above concerns only microcrystalline systems and is not entirely relevant in the case of the conditions indicated by you initially.

 

[orvi]

This is not an assumption.
Hydrates, clathrates, suspensions, emulsions, true solutions containing water - everything corresponds to these calculations when water molecules pass into the solid phase.
This is due to the fact that water molecules are practically incompressible in any liquid system.

You can easily verify this experimentally in a couple of hours

As for ruptures of HDPE vessels filled to 70%, the problem is much more often associated with the quality of processing of their internal surface and insufficient wall thickness.

Yeah, I see that it generally apply well in many scenarios, and also, it is evident with that nitric hydrate or trihydrate, where trihydrate will apparently have lower contraction upon freezing than monohydrate.

But it isn´t linear, and I do not like to rely on that kind of assumption (I had several accidents, unrelated to this toppic, where I assumed something would follow some pattern - and it simply doesn´t). Of course, it does work in many cases, but water solutions are unique due to variety of different possibilities of hydrogen bonding. Plain water vs. some other chemicals, which are better electron donors/acceptors, can make stronger H-bonds in between water+whatever chemical, which persist even in solid phase, compact the lattice and change the outcome. And some does the opposite, like many fluorine containing molecules.

It is also nicely seen by formation of various azeotropes of water with polar water soluble substances like HCl, nitric or others. Change of boiling point vs. temperature or content of the other chemical isn´t linear due to unique possibilities of hydrogen bonding in the liquid. That is why azeotropic 68% nitric boils at around 120 °C - ratio of nitric/water molecules in this mixture is just right to form tightest hydrogen bonding patterns that "interlock" both chemicals and higher the ammount of energy needed to free them into vapor phase.
It isn´t the exact thing as freezing something, obviously, but many of the same principles apply also for freezing.

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Yup, I completely agree with this. Also, prolonged storage of nitric can deteriorate the HDPE and make it brittle in relatively short time. That is why I also added "catchpans" for these containers. Just in case

We will see after the winter, how it held but I am assured now that any risks are very low.

 

[orvi]

"Crystals were grown by cooling equimolar aqueous solutions of nitric acid sealed in glass capillaries
(m.p. -36.0°C). The intensities and cell dimensions were measured with a Stoe-Philips semi-automatic
two-circle diffractometer (Cu K~, Ni-filtered, moving crystal-moving detector scan technique) modified for low-temperature studies. Measurements were obtained at 85 and 225 K from two cylindrical crystals (diameter 0.10 mm, length 0"30 mm) mounted about a and c respectively. "
--------------------------
It seems to me that this data from the both .pdf articles mentioned above concerns only microcrystalline systems and is not entirely relevant in the case of the conditions indicated by you initially.

X-ray diffraction need single crystals to work properly, there must not be any dislocations or disorders in the structure, otherwise, diffraction pattern could not be resolved. At least, it was this way in the times when these folks were doing this Now we have better equipment which could deal with some minor disorders or interlocked areas of some other phases, that is for sure.
In order to prepare monocrystals this small, you need to go very slow and grow them very slowly and steadily - which would be also the case of possible freezing of my canisters.

But when it comes to my original goal - to see if there could possibly be any dangerous increase in density upon freezing - I am pretty confident there wouldn´t be any in the case of nitric acid. All crystal phases that could emerge upon freezing of the nitric have higher density than original liquid (if we say the measurements in articles are correct). For 65% nitric, first phase emerging as solid is trihydrate, since it has highest melting point = freezing first. Ice formation do not appear in phase diagrams, indicating that formation of trihydrate is preferred at this concentration window. It would deplete the solution of water, enriching the concentration of nitric in the mother liquor down to monohydrate, which will be then sole constituent of liquid phase. If there aren´t any other and special phases emerging, this is how the system should behave. Crystallization would be very slow, since the volume is big and heat transfer through double HDPE layer is relatively bad - equilibrium should be maintained fairly well.

Contrary with peroxide issue, there is indicated ice formation at the start of the process, since only distinct phase forming with peroxide is the dihydrate, and 30% stuff is below the concentration needed for preferrential crystallization of dihydrate (which have mp of around -52 °C) - so ice will appear first, only then followed by freezing the whole rest of the mother liquor as predominantly dihydrate.
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You can indeed use these physical properties to your benefit in some special cases, for example purification and drying (to some extent) of DMSO by partial freezing (fp for DMSO is 19 °C).

 

[Ultrax]

I read the articles more carefully, perhaps you are right about the nature of the change in density in a mixture of high-purity nitric acid and distilled water without additional impurities that prevent the formation of hydrates, but when we store technical nitric acid 56% (with unknown impurities) in winter (about -25C) in an unheated warehouse, the cork from the bottle of acid has been pushed out, which means that the volume has increased.

 

[Ultrax]

P. S. What I can say for sure is that nitric acid slowly dissolves dyes from HDPE containers (we tested this from our own experience). Therefore, we do not store it in such containers for a long time, also assuming that such containers are not very reliable for storing nitric acid.

 

[Ultrax]

I found a reference diagram for HNO3 density. (Unfortunately, I don't have an English version of this diagram)