Nitrostarch Synthesis
The synthesis for nitrostarch is quite similar to the one for nitrocellulose. Cellulose and starch are actually similar to each other in that they are both made of monomers of glucose, except with monomers in starch being connected by alpha-1,4 (and some alpha-1,6) glycosidic bonds and the monomers in cellulose being connected by beta-1,4 glycosidic bonds. Being comparable to the synthesis for nitrocellulose, it is a farily easy nitration and not too much trouble to follow through. Again, one must always take the necessary precautions when dealing with dangerous chemicals.
The materials required are the same as for nitrocellulose, except cellulose is replaced with starch. When preparing this I used 30 ml H2SO4, 20 grams NH4NO3, and 4 grams of starch (theoretically you should be able to use over 8 grams of starch here, but I just used 4). The temperature of the acid goes up as the NH4NO3 dissolves and so I allowed it to cool down to about 10 Celsius before adding the starch. This was done in the fresh fallen snow outside.
Once it was cooled, the starch was added with stirring while keeping the temperature at around 10 Celsius. This was stirred for a bit more and then allowed to sit for about 2 hours with stirring every once in a while. After 2 hours it should be ready and so it's time to clean it up. Cold water was added to the mixture, stirred, allowed time for the nitrostarch to settle, and then decanted. This was was done a few times. It was then washed with a sodium bicarbonate solution to neutralize remaining acids. The nitrostarch was then allowed to dry after being filtered. Here is a picture of it in the filter.
The nitrostarch can be purified to remove any impurities. To do this, the nitrostarch is dissolved in acetone. You can then remove any impurities like starch that wasn't nitrated. To recover the nitrostarch, simply crash with cold water and let precipitate. What forms is a sort of goo-like material that is the nitrostarch. Just filter it and let it dry. You now have nitrostarch that is ready for use.
I only got about 2 grams after all was said and done but quite a bit was lost in some various steps, so it was probably closer to 3 grams. It burned relatively slowly with a tall tower of flame. I'm not too fond of this but it was something to make. I'll try again sometime using KNO3 and see if that makes any difference since using alkali nitrates gives better reactions in other syntheses.
