Chemical Forums
Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: jfergua on February 01, 2018, 11:52:28 AM
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What is the technology of choice at industrial scale to separate m-xylene from the mixture of isomers?
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Did you try googling "separation of xylenes?" I got several papers such as these
http://pubs.acs.org/doi/abs/10.1021/ie50542a028
http://pubs.rsc.org/en/content/articlelanding/2015/cc/c4cc05329j#!divAbstract
The basis for them seems to be you find something that will solidify with only meta or para xylenes , then you can fractionally distill off the other from the ortho xylene because have 5°C BP seperation.
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Thanks for your reply. Yes, we have googled the subject and apparently it is common practice to separate the ortho isomer from the m and p mixture by fractional distillation. Then the m + p mixture is subjected to fractional crystallization at very low temperatures in the presence of eutectic modifiers to separate the m isomer. Yet we were hoping there was an easier economic way not requiring huge scales.
Can separation be accomplished via derivatization as, for example, after partial oxidation of the mix?
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It is common at industrial scale to increase the pressure during the fractional distillation. By doing so, 5°C BP seperation at 1 atm can be much higher at increased pressure. On the other hand, this technique needs specialized equipments/facilities.
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These patents (same inventor) recommend azeotropic distillation to separate the meta from para (1K difference):
https://www.google.com/patents/US5039380
https://www.google.com/patents/US5445715
https://www.google.de/patents/US5466345
It could be cheaper than cold.
Could that distillation be an application for my thingy there? Just a way to put more plates in the same volume
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