After organic synthesis of a new compounds, how does one determine a suitable method that can help to efficiently isolate your desire compound from the reaction mixture?
There are a couple of reasonable answers, which is right depends upon the chemist and the reaction.
1. Find the most similar compound in the literature (SciFinder "similarity search" works well for this) and work up your reaction the same way. For the vast majority of compounds, synthetic procedures exist, and you will not need to reinvent the wheel. However, for those that do not, odds are that there is a very similar compound, whose work up and purification conditions will work very well.
2. The second approach is for the more advanced researcher, with a few solid years of experience. In this approach, you use the same general scheme as approach 1, but use your chemical intuition to adjust the procedure to be more appropriate to your compound. For example, if a work up calls for extraction with diethyl ether, and your compound is insoluble in ether (or you expect it to be poorly soluble) use dichloromethane, chloroform, or toluene. Having a chemical intuition is necessary because if you don't your compound could be lost or decomposed during work up, so the key is to think carefully about what can (and will) go wrong.
Once you've worked up a few hundred reactions, you will have seen and solved essentially every work up challenge, and from there you just need to apply different lessons to a new situation.
There are a couple of reasonable answers, which is right depends upon the chemist and the reaction.
1. Find the most similar compound in the literature (SciFinder "similarity search" works well for this) and work up your reaction the same way. For the vast majority of compounds, synthetic procedures exist, and you will not need to reinvent the wheel. However, for those that do not, odds are that there is a very similar compound, whose work up and purification conditions will work very well.
2. The second approach is for the more advanced researcher, with a few solid years of experience. In this approach, you use the same general scheme as approach 1, but use your chemical intuition to adjust the procedure to be more appropriate to your compound. For example, if a work up calls for extraction with diethyl ether, and your compound is insoluble in ether (or you expect it to be poorly soluble) use dichloromethane, chloroform, or toluene. Having a chemical intuition is necessary because if you don't your compound could be lost or decomposed during work up, so the key is to think carefully about what can (and will) go wrong.
Once you've worked up a few hundred reactions, you will have seen and solved essentially every work up challenge, and from there you just need to apply different lessons to a new situation.
As Jason said. Resuming, the Synthetic Chemist, generally have some expertise ot knownledge about the chemical "nature", or the chemical general properties of new compound to be isolated.
example, if your new desired compound is a ketone, it can be isolated by extraction from their aqueous mixture with a organic solvent, as ethylacetate.
If the compound appears to contain an carboxylic acid group it may be isolated as potassium salt.
In a very overall approach, generally, organic compounds, when solid and insoluble in water, are isolated by quenching the reaction mixture, addint it do ice.
For liquids, water soluble compounds, even for some compounds soluble in organic solvents etc...
the solvent of the reaction is removed partially or totally, in vacuo, with the aid of a rotary evaporator, and the residue, if solid is recrystallized, and if liquid, or oily, extracted with other suitable solvent as hexane, alcohol, ethyl acetate, ether etc...
after drying the organic layer with magnesium or sodium sulfate, another evaporation in vacuo, leeds to isolate the compound.
Some general procedures are collected at this link.
http://www.ecompound.com/Reaction%20reference/Lab%20rat%20procedures.htm
Please thanks for the interest you showed for my question.
http://www.scripps.edu/shenvi/Education_files/work%20up%20tips.pdf
This link is a pretty good primer in this area.
You can try
Vogel's Textbook of Practical Organic Chemistry 5th edition
Book by Arthur Israel Vogel
In addition to this great particular, you may also check other books still written by Vogel.
use this link to get the book
http://books.pakchem.net/vogels-textbook-of-practical-organic-chemistry.html
You can referer standard books for reaction mixture separation i)Text book of practical organic chemistry by A.I.Vogel ii) Practical Oranic Chemistry by Mann & Sounders iii)A Hand book of Prac tical Organic Chemistry by H.T.Clarkes
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