[ABA2015]

hi
I have tried to do saponification experiment, but in the first stage I could not achieve the pasty mass after heating oil, sodium hydroxide and ethanol. I don't know why 
I achieved a dry powder instead of pasty mass.

[Arkcon]

That does sound strange.  What fat did you start with?  Was it an oil, and what type of oil was it -- olive, etc.  It wasn't a saponifiable solid fat, was it?  Anyway, even when salting the completed soap out, you get curds, not a dry powder.  I assuming you used a strong solution of sodium hydroxide, with a little alcohol to help it mix before soap began to form, and helped it the rest of the way.  You didn't just mix some NaOH pellets, alcohol and vegetable oil, right?

[ABA2015]

That does sound strange.  What fat did you start with?  Was it an oil, and what type of oil was it -- olive, etc.  It wasn't a saponifiable solid fat, was it?  Anyway, even when salting the completed soap out, you get curds, not a dry powder.  I assuming you used a strong solution of sodium hydroxide, with a little alcohol to help it mix before soap began to form, and helped it the rest of the way.  You didn't just mix some NaOH pellets, alcohol and vegetable oil, right?

thanks for your attention dear Arkcon, yes it was an oil, unfortunately I'm not sure about which kind of oil it was , I heated 2.5 gr oil with 10mL ethanol and 2.5gr sodium hydroxide (which I tried to dissolve in mentioned ethanol) and I stirred to achieve pasty mass but it gave me dry powder, by the way I continued the reaction with that powder, and I prepared soap although I couldn't achieve that viscose saponification solution at the end for shaping the soap but it had foam
 

[Arkcon]

Nope.  Not enough NaOH will dissolve in order for that to work.  You will have to dissolve the NaOH in water, then add it to oil (a saponifiable one -- olivie oil will, mineral oil won't,) ethanol to mix, and as soap forms the rest of the water solution of NaOH will mix with the oil. 

Now, for an analytical test for saponifiable substances, I can use methanol saturated with KOH.  But in that case, I'm not trying to make soap.  I'm trying to make sure I can't make soap, or at least I can only make a little bit.

[ABA2015]

thank you very much Arkcon    I will try again