[Pablo]

Dear friends,
I need some help of you.
I am doing a catalyst made from La Co Ni. I use hydrated nitrates of this elements combined with citric acid and ethylenglycol in the method to obtain a gel. This gel produces a exothermic reaction when I put it on the oven at 110C overnight, and I lose all the material because this kind of explosion removes the material being drying from its recipient. Could you tell me Why it phenomenon occurs?. Is it kind of explosion due to the La, Ni or Co, which I use in the synthesis?.
Best Regards
Pablo.

[discodermolide]

Dear friends,
I need some help of you.
I am doing a catalyst made from La Co Ni. I use hydrated nitrates of this elements combined with citric acid and ethylenglycol in the method to obtain a gel. This gel produces a exothermic reaction when I put it on the oven at 110C overnight, and I lose all the material because this kind of explosion removes the material being drying from its recipient. Could you tell me Why it phenomenon occurs?. Is it kind of explosion due to the La, Ni or Co, which I use in the synthesis?.
Best Regards
Pablo.

Just a thought are you nitrating the ethylene glycol? Thus producing an explosive compound at 110°C.
Try the drying at a much lower temperature, 30°C and apply high vacuum.
Also I would run a DSC of your mixture to see exactly where the exothermic decomposition starts.

[Arkcon]

It would really depend on the specific reference to give you the correct procedure.  But as a knee jerk reaction, you should probably use a vacuum oven, or a chamber purged with an inert gas, if your starting materials are nitrates.

[Borek]

In general heating nitrates with organic compounds sounds like a disaster waiting to happen.

[Pablo]

Thanks a lot my friends for your replays.

Even I don't use ethylen glycol, which means that starter materials are La Co Ni nitrates and citric acid, the material go away from its recipient when I put it inner the muffle, at 1C/min, until 500C. So I have become to believe that it phenomenon is due to hydration during its storage, which is about 5 days. Why do you think?, Is it correct?. Can you tell me some reference to learn more about it problem?
Best Regards.
Pablo

[discodermolide]

Thanks a lot my friends for your replays.

Even I don't use ethylen glycol, which means that starter materials are La Co Ni nitrates and citric acid, the material go away from its recipient when I put it inner the muffle, at 1C/min, until 500C. So I have become to believe that it phenomenon is due to hydration during its storage, which is about 5 days. Why do you think?, Is it correct?. Can you tell me some reference to learn more about it problem?
Best Regards.
Pablo

As I said above run a DSC then you will see the decomposition profile. Heating nitrates is not a good idea, lots of nitrates cause things to "go away".

[Pablo]

Dear discodermolide
Thanks for you answer. I am new at doing this kind of work. Please, Could you tell me some references which explain more about the explosions from nitrates?. I don't know if it would be a good idea to run a DSC  in air atmosphere of my material, because I think It would cause some damage in the thermal analysis equipment due to the exothermic reaction, even I use about 3 mg of my material, don't it?. Or Are you suggesting me to run the DSC using inert atmosphere?. Using inert atmosphere, Would I get the material decomposition profile?
Best Regards
Pablo. 

[Arkcon]

I did a little Googling and I found a similar reference shortly after your original post.  From this reference:  http://www.ipcbee.com/vol25/23-ICNB2011_Q30012.pdf  I found a step by step protocol for building nano powders from nitrate salts that are previously made into a sol-gel with citric acid and ethylene glycol.  The reference also provides thermogravimetric data.  Does the reference you're working from provide a similar sort of protocol?

The nitrates were dissolved with 100 ml of de-ionized water to get a clear solution. water to get a clear solution. Aqueous solution of citric acid was mixed with the nitrate solution. The solution was evaporated on a hot plate at 60˚C for 4 h. Then ethylene glycol was added at 80˚C. The solution was slowly evaporated until a highly viscous residue was formed and then the viscous residue was heated at 180˚C for 4h. With continuous heating on the hot plate, the gel ablated and bubbled up as temperature
increased.  The gel started to swell with the evolution of a large amount of gases and was finally burnt with
glowing flints. Finally the brown-colored powders were calcined at 1270˚C for 4 h.

[Pablo]

Dear Arkon,
Thanks for your replay.
There is no thermal analysis made from the work I use as a reference. This work was a master's thesis made from a friend of mine and He explained to me He didn't have this problem, maybe because He worked with Mn and Sr against Co and Ni.  Are there books which explain the explosion from chelates made from ethylene glycol, citric acid and metal nitrates as precursors?. Would be a good idea to decompose the gel with inert atmosphere against with air atmosphere at 500C?
Best Regards
Pablo.