Technically, yes. But as others have noted, the short answer is no.
I've produced about 10 pounds of VG (and animal glycerine, exactly the same chemical formula) just as a byproduct this year. In my case, I didn't separate it--I wanted it in the final product.
Some soap makers do separate it for one reason or another. Raw VG/AG is brown and filled with impurities. It can be purified, but it's time consuming. Basic distillation is easy, but getting it up to pharmaceutical grade is difficult and expensive.
All things considered, and given the (cheap) price of the stuff, just
buy it.