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I will really need your help. I am chemist working in the oil buisness and I am interesting is it possible to analyze propane (Liquefied petroleum gas). We are analyzing propane with GC method but we need structural analysis as a proof for submitting our dossier for registration of product. with regards! Silvija! |
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Silvija, It's hard to tell from your message if you wish to analyze propane as a liquid or a gas (or perhaps a solid ;). Let's assume for the moment that you wish to to analyze it as a liquid. You will need to put the liquid propane into a high pressure NMR sample tube. These can be commercially purchased. For example perform a search on high pressure NMR tube. You might also look into this Wilmad High Pressure Technical Note for more good ideas. You'll need to prepare some sort of suitable sample handling and loading manifold since it's not really convenient to pour liquid propane into a sample tube under atmospheric conditions. You'll also need to include a deuterated solvent for field/frequency locking purposes. The choice might require a bit of experimentation but I suspect that deutero-acetone in a 50%/50% (V/V) mix with your liquid propane is a good place to start. Once again, you might perform a search on NMR of liquid propane to see how others may have handled the same situation. If you wish to perform 13C spectroscopy on the sample don't be surprised to find a fairly long T1. The sample concentration is high so it should be a reasonable experiment. Maybe you want to perform another search to see what has been already done... You'll need to think hard about limits of detection in all these experiments but you already knew that. ;) Let's not think about gaseous or solid propane NMR experiments unless you're really feeling adventurous. Best regards, We want to analyze propane as a liquid. This is very very helpful. Best regards, Silvija. - Silvija (Apr 20 '10 at 05:10) |
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Silvija, Your questions was pointed out to me by the administrator of this website while at a trade meeting for NMR users. The company I represent sells equipment for high pressure and high temperature NMR experiments. We also offer high pressure syringe pumps that were originally designed for delivering high pressure liquid ethane. We have two versions of our NMR cells, one has an integrated needle valve for storing pressurized samples for extended periods. The tube is 5 mm I.D. x 3.6 mm O.D. and can be used up to 1,000 bar. This would be well above the liquefaction pressure of propane. The other version of the cell requires constant connection to a pressure source but can be used up to 2,500 bar and is meant more for experiments where multiple pressure points are to be collected. The tube dimensions for this tube are 5 mm O.D. x 3 mm I.D. More information can be obtained at www.daedalusinnovations.com. Let me know if we can be of help. -Ron |
Hi Silvija, maybe you could clarify - what exactly you mean by the need to analyze propane? Do you need to detect it in the mixture, determine concentration, confirm purity? - Evgeny Fadeev (Apr 20 '10 at 02:25)
also - I've edited title of your question - does it sound right? - Evgeny Fadeev (Apr 20 '10 at 02:30)
We need to confirm purity. The question sound right, long working hours,what can I say thnx:) - Silvija (Apr 20 '10 at 05:02)