The reaction I'm undergoing is esterification for the synthesis of biolubricants. After the reaction, I can't seem to find a good way to remove the acid catalyst. Journals suggest water-washing (hot and cold have been suggested and tried) and some using small amounts of sodium bicarbonate for neutralization.
It just seems that the pH doesn't go down very much. Any other suggestions? Appreciate your responses. Thank you.
Washing with low concentrated solution of sodium bicarbonate is good solution, if there is not a salt formulation of your main product during the process.
You would get more answers if you mention your catalyst and solvent (reactand)
One of the way to recover a homogeneous catalyst is an extraction of product by organic solvent with low boiling temperature. The aqueous solution can be reused as a catalytic mixture.
I agree with Jürgen here. If you would be more specific, we could help you better. Another way to remove ( i.e. not recover) your catalyst is flash chromatography with diatomaceous earth, silica, alumina or equivalent, assuming that your acid catalyst is very polar and you product isn't.
Be specific about the nature of the catalyst. In a typical homogeneous reaction, your catalyst will also be in organic medium and separation, when reaction is performed in large scale, involve various separation methods. If you are not interested in its recovery (bit difficult), simply filter the reaction mixture through activated silica or alumina or diat0maceous earth as suggested by Luc and that should help. One has to be very specific while posting a question.
Best
Balakrishna
For those asking what type of catalyst I'm using, Luc Alders , Jürgen Wintner .
I'm using concentrated sulphuric acid.
And in response to some of your suggestions and comments,
Thank you
how to remove catalyst (AlCl3-NaCl molten salt) from polymeric carbon materials? these materials are usually black in color and to use for electrode materials in battery. after completion of reaction i need to remove the catalyst from reaction product. its a more specific question. please share your knowledge.
Mr. Brandon Ng,
As reported in most of the publications, ice cold water should satisfy your's requirement. But in some cases may not happen. In such cases low molar base solutions of sat NaHCO3 or NaOH may fulfil your's deed. If face any stability related issues, you may also try with sat NH4Cl solution. Your's product may be extracted into organic solvent.
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