[RDSpecialist]

Hello everyone,

For our production and quality control unit at our factory, we need to test the quality of ethyl acetate, which we use as thinner to mix with paints in the printing process of wooden products. We simply saw that the quality of ethyl acetate is not good something and it doesn't dissolve in paints. SO we would like to test the quality when the product comes to the factory.

I thought I can use a hydrometer to test the purity but it seems like even a bad sample gives the same result roughly. My other option is to get a distillation set-up and try to determine the boiling point, but one of the possible impurity, which is, ethanol, has a similar boiling point.

Do you have any idea how to test the purity of ethyl acetate in a practical way? Do you have any other suggestions? Or What do you say about hydrometer, boiling point determination, TLC maybe or FTIR?

Thank you in advance,

Regards

[DrCMS]

I'd look to do run it through a GC to check the purity and also do a KF to check water content.

[RDSpecialist]

GC-like instruments sound expensive for the factory, but I will keep it in mind. And I think KF method woudl work fine..

Thank you very much for your reply and interest

Regards


Any other things you can come up with, friends??

[Arkcon]

Briefly, you need to know how good the ethyl acetate has to be.  That means you have to know how pure the ethyl acetate needs to be, and what impurities, at what level, are detrimental.  That means a gas chromatography run, to test for other solvents and water, or Karl Fisher analysis, to test for water, as DrCMS: mentioned above.  Maybe a pH titration, if you think acetic acid and water are impurities.  And multiple tests on your part to determine what levels are acceptable for your application or not.

You might get away with doing this once time, to determine what will and won't work, setting a level that's acceptable, and telling the vendor something like -- 98% ethyl acetate, no more than 100 ppm water (I'm guessing here), no detectable acid.  Warning: they will charge you extra for a standard of purity, even if 9 times out of 10, their stock will pass anyway.  Double warning: they may send you a certificate, but not bother to test at all, then it may fail, and then you will have to prove it, so you may want to get a contact with an analytical lab to test your raw material often, or every time, or you may want to purchase a GC, KF, autotitrator.  It really depends on the rigidness of your application, how your vendors treat you, and your bottom line.

ETA: Credit DrCMS: for a correct first answer

[RDSpecialist]

Thank you very much, it was a really clear and helpful reply.

Regards