Hi All,
I've been reading about chemistry alot lately as it was a subject a school I really enjoyed and now I am thinking of going back in to further education and I'm looking at all my old lessons etc. I understand distillation perfectly although what if this scenario comes up? A mixture solution of chem A, B, & C where you want to obtain pure chem B. Chem A has a BP of 70deg, B80deg and C 90deg. Now I would say that you would heat the solution at 70-72deg for so long until no more evaporates then discard the content of the the receiving flask then heat solution up to 80-82 to get the desired one. Is this correct of is there a much simpler one step approach to this?
I've been reading about chemistry alot lately as it was a subject a school I really enjoyed and now I am thinking of going back in to further education and I'm looking at all my old lessons etc. I understand distillation perfectly although what if this scenario comes up? A mixture solution of chem A, B, & C where you want to obtain pure chem B. Chem A has a BP of 70deg, B80deg and C 90deg. Now I would say that you would heat the solution at 70-72deg for so long until no more evaporates then discard the content of the the receiving flask then heat solution up to 80-82 to get the desired one. Is this correct of is there a much simpler one step approach to this?
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In theory you could separate the chemicals that way but in practice you would probably find that those boiling points are too similar for them to be separated by distillation with a reasonable level of purity. For example I think it's impossible to get more than 90% pure alcohol from an aqueous solution by distillation as the boiling points of ethanol and water are similar.
Use of a fractionating column can help to condense any less volatile substances so that they are returned to the flask and try to make sure that only those at the correct temperature are extracted. However, this is not perfect. I believe that you can have a combined fractional distillation where there are several levels and chemicals of different boiling points are extracted separately and simultaneously. I think that they use this for fractional distillation of crude oil.
Use of a fractionating column can help to condense any less volatile substances so that they are returned to the flask and try to make sure that only those at the correct temperature are extracted. However, this is not perfect. I believe that you can have a combined fractional distillation where there are several levels and chemicals of different boiling points are extracted separately and simultaneously. I think that they use this for fractional distillation of crude oil.
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O