I am trying to determine how to analyze a product I made from PLA polymerization. However, the Lactic acid I used are ones that was made using an unorthodox method of producing Lactic acid (we are testing how efficient it is) and therefore, I don't know anything more than some compounds inside the solution, which are: Lactic acid, Acetic acid, and Glucose.
When I tried to polymerize it using polycondensation (using catalyst), I was able to get a sticky liquid (but not solid) that I am quite certain is not PLA (at most, oligomer), but I am not sure how to determine with certainty that it is not.
I tried dissolving it in Water, Chloroform, THF and Acetone; it only dissolve in the first one. At first I thought using NMR might work, but then I'll be getting data with a lot of noises because of all the impurities. So I tried to purify it, but now I don't know how to pick which solvent to use for a precipitation process.
10mL Lactic A. + 3drops H2SO4 @110oCx30min -> PLA
I suggest you getting familiar with the main components, then you'll like to press your yield by something and using Le Chatellieur, after you have tiny or minor amounts of unwanted sub-product then is easy to separate. For a complex mixture being separated you need to know all components and then design a specific step by step process, for that is useful getting familiar with the original components, or those present at mixture. Sometimes a tiny data from each component suffices to reach separation(search properties for all participants)
You may try alcohol to dissolve and precipitate it in ethyl acetate, petroleum ether and many other solvents. If only soluble in water precipitate in chilled alcohol, THF. You can make a mixed solvent combination (Water/alcohol or THF; Water ratio lowest possible) and dissolve. Keep it in freezer, crystal or solid may come out
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