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Topic: an accelerator for calsium oxalate formation  (Read 12694 times)

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Offline alex00

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an accelerator for calsium oxalate formation
« on: December 28, 2012, 06:21:33 AM »
Hi
Do you know any accelerator agent for this reaction ?

H2C2O4 + 2CaCO3 →CaC2O4 + CO2 + H2O

I need this reaction take place fast and completely.
Thanks

Offline Schrödinger

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Re: an accelerator for calsium oxalate formation
« Reply #1 on: December 28, 2012, 08:02:47 AM »
What do want from this reaction? Because if water is only a byproduct, maybe you can try to remove water by some easy and fast method. That should speed up the process. Similarly with CO2 and CaC2O4
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Offline alex00

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Re: an accelerator for calsium oxalate formation
« Reply #2 on: December 28, 2012, 08:09:04 AM »
hi
I am looking for a chemical agent that cause speed

Offline curiouscat

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Re: an accelerator for calsium oxalate formation
« Reply #3 on: December 30, 2012, 09:09:26 AM »
hi
I am looking for a chemical agent that cause speed

i.e. Catalyst?

How fast does it currently happen?

Offline curiouscat

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Re: an accelerator for calsium oxalate formation
« Reply #4 on: December 30, 2012, 09:10:04 AM »
H2C2O4 + 2CaCO3 →CaC2O4 + CO2 + H2O

What form is your CaCO3 in?

Offline stewie griffin

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Re: an accelerator for calsium oxalate formation
« Reply #5 on: December 30, 2012, 04:17:50 PM »
If you use calcium carbonate then I'd heat the reaction mixture >60°C.
What size is your calcium carbonate? Can you mill it finer so it reacts better?
Why not use the more reactive calcium oxide (or Ca(OH)2) instead of the carbonate?

Your slow reaction is probably due to the fact that you've got an insoluble carbonate base, and you are forming an insoluble product. So you may end up with some calcium carbonate occluded in your precipitated calcium oxalate. Unfortunately calcium oxide is also insoluble so you run into similar problems.
I'd try a metathesis between sodium oxalate and calcium chloride. Both salts should be water soluble, so you could have two solutions made up (one of Na2C2O4, and one of CaCl2) and then do a co-addition into a reaction vessel. The mother liquor with have NaCl and you can just isolate your calcium oxalate via filtration/washings. 

Offline alex00

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Re: an accelerator for calsium oxalate formation
« Reply #6 on: January 07, 2013, 01:18:02 PM »
CaCO3 is Stone and I want react it with stone so I can not change it. I need a compound of oxalic acid that react with CaCO3. I need a bright crystall of calcium oxalate
I need a catalyst.

Offline Borek

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Re: an accelerator for calsium oxalate formation
« Reply #7 on: January 07, 2013, 01:49:40 PM »
If what you need is a crystal of calcium oxalate you can dissolve the oxalic acid in water, add calcium carbonate till it dissolves, and the dry the solution out.

You may call water the catalyst if you like.
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Offline Schrödinger

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Re: an accelerator for calsium oxalate formation
« Reply #8 on: January 08, 2013, 04:30:21 AM »
Guys, if oxalic acid and calcium oxalate are used both in their solid forms, is the reaction even possible without a solvent like water?
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Offline alex00

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Re: an accelerator for calsium oxalate formation
« Reply #9 on: January 09, 2013, 12:43:44 AM »
CaCO3 and Oxalic acid are solid. I need a glassy material that obtain from CaCO3 like Calcium oxalate with property 1.glassy 2.shiny 3.crystall 4.high hardness
do you know any other composition like it? I need a reaction that occur fast with the base of CaCO3 and a solid acid like oxalic acid or a salt of acid like potassium oxalate. Is there any other reactions?

Offline Borek

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Re: an accelerator for calsium oxalate formation
« Reply #10 on: January 09, 2013, 03:52:01 AM »
There will be no fast reactions between solid CaCO3 and other solids. Solids in general react very slowly, as the reaction rate is limited by the diffusion. You can speed it up by heating, but - in the presence of calcium carbonate and oxalates - you will see them decomposing, not reacting.
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Offline alex00

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Re: an accelerator for calsium oxalate formation
« Reply #11 on: January 09, 2013, 05:46:06 AM »
I mean in the water. the solid acid or their salts dissolving in the water and then react with the solid CaCO3

Offline curiouscat

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Re: an accelerator for calsium oxalate formation
« Reply #12 on: January 09, 2013, 06:07:05 AM »
What's your purpose?

Offline Arkcon

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Re: an accelerator for calsium oxalate formation
« Reply #13 on: January 09, 2013, 10:09:38 AM »
rasool083:, I'm going to try to pull together what you've been saying, without the guesses you've forced everyone else to make, and see if we can get a clearer picture of what you want.

Hi
Do you know any accelerator agent for this reaction ?

H2C2O4 + 2CaCO3 →CaC2O4 + CO2 + H2O

I need this reaction take place fast and completely.
Thanks

I don't know what an "accelerator" means in this context.  That's not a chemistry term, really.  That makes it hard to understand the question.  If you mean catalyst, you should say "catalyst".  But you only mean "catalyst" if you can use the definition of the word catalyst in a chemical sense -- something that speeds a reaction by lowering activation energy.  The reaction of a carbonate and an acid is generally rapid enough, so we're still confused.

hi I am looking for a chemical agent that cause speed

Hi.  That statement is nonsense.  You restated the original question, using even less chemical knowledge, using even worse terminology.  Like its been said a few times, this reaction should be fast enough.

CaCO3 is Stone and I want react it with stone so I can not change it. I need a compound of oxalic acid that react with CaCO3. I need a bright crystall of calcium oxalate
I need a catalyst.

OK, there are a few things wrong right here.  Clearly you can't take the advice that grinding the solid will improve reaction time.  OK  But you want to react it with a compound of oxalic acid.  But the oxalic acid isn't the problem, so how will that help?  Also, a compound of oxalic acid won't react like oxalic acid.  So you need a catalyst, but why, if you're changing the reactants?

CaCO3 and Oxalic acid are solid. I need a glassy material that obtain from CaCO3 like Calcium oxalate with property 1.glassy 2.shiny 3.crystall 4.high hardness
do you know any other composition like it? I need a reaction that occur fast with the base of CaCO3 and a solid acid like oxalic acid or a salt of acid like potassium oxalate. Is there any other reactions?

OK, clearly (well, as clear as it gets for me), you need a perfect crystal of calcium oxalate, and not a dry powder gradually formed from the reaction of a carbonate and oxalic acid.  Turns out, that's a little bit easier to arrange.  You can grow clear crystals of insoluble salts, you just start with soluble salts, and mix them, slowly diffusing them together.  A good way to achieve this is to use gel media to control the diffusion.  You want the following textbook -- Crystal Growth in Gel Media here's the Amazon link: http://www.amazon.com/Crystal-Growth-Gels-Heinz-Henisch/dp/0486689158  Briefly, you'd prepare a gel, say of sodium silicate or maybe you can use an organic gel like agar or gelatin, in something like a U-shaped tube, and put reservoirs of calcium chloride and oxalic acid solutions in each side, and they'll diffuse gradually together, forming crystals where they meet ... sloooowly.  Because if you want a crystal, you have to grow it slowly.  If you speed up crystal formation, which you keep asking for, you get powder instead.  The textbook above also explains that concept well.  We all know that, so its hard to understand your purpose, when you keep asking for things that will ruin your results.
Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

Offline alex00

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Re: an accelerator for calsium oxalate formation
« Reply #14 on: January 09, 2013, 12:32:40 PM »
excuse me, perhaps I must described the problem first. I want to recrystallization the marble. marble contain CaCO3 and the it`s recrystallization occur in present of Oxalic acid due to Calcium oxalate formation.
in the stone factories they using some brick that rubbing on the stone in present of water.the bricks contain oxalic acid and Al2O3.
The problem:
1. when the factory speed up their line speed the surface quality of the stone will decrease. so I think perhaps there is a agent that could act as an catalyst.
2. in some where in the surface of stone there are some dark zone I think it is for low amount of CaCO3. so it must have some other composition. I am looking for a reaction like above that have good crystals and glassy.
Thanks

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