Ummm.... Y'know, it was never intended to boil the mixtr, especially if you use eqiumolar amts of acid and alcohol. That is a certain way to get some ether - in fact, that's how it's industrially made
.
The whole point of heating it is pretty unclear to SWIM
, but he did it anyway, because that's what the proc on Rh's said - guess it speeds up the initial rxn, till it reaches equilibrium. Another point is that Na2SO4 won't bind water at higher than 32 C, so if you add it while hot and shake it as it is cooling to this temp, you will prevent caking, which is pretty necessary, i believe - the less Na2SO4 you use, the better.
I also want to note that SWIM's xperience suggests that it is often necessary to let the rxn proceed for some time - like, leave it overnight - to allow complete conversion. I really wish that someone w/TLC could look at the dynamics of this rxn, it's really confusing all the way.
I also wish very much that Foxy2 supply us all the additional details of that article on HEtSO4 preparation, esp. the time and proportion of alcohol 2 acid.
Another notion - i believe that when performing neutralization in alcohol, the degree of convertion of H2SO4 can't bee judged by the final SO4-- percentage, since alcohol undoubtedly reacts w/H2SO4 formed in hydrolysis.
What i'm trying to say, i'm not really sure as to what time, Na2SO4 quantity etc. are needed for optimal results, and this procedure needs very much to bee optimized - unfortunately, SWIM has neither money, nor equipment for doing this.
As for the test - it is based on the simple fact that CaSO4 is only very slightly soluble in water (200 mg per 100 ml), while CaAlkSO4 is well soluble. So what you do is make a conc. soln. of CaCl2, a conc. soln. of a weighed amt (somewhat less than CaCl2) of your salt, mix it, filter the precipitate, wash it w/aq., dry it well - roughly speaking, the weight of it will equal the weight of Na2SO4 in your salt (that is, if you dried the NaEtSO4 at above 32 C!).
This test is probably very imperfect, cause CaSO4 is still pretty soluble in water, more than that, presence of inorganic cations fucken increases its solubility - have no idea how much, does anyone?
Well, that's about all i can say thus far, but - an important notion - bee sure to fuse your nitrite bee4 the rxn, it seems to bee important, and it's usually quite wet (very hydroscopic).
Good luck,
Antoncho