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Nitrostarch

Formula
Weight
VoD
Drop Test Score

monomer: C6H7O2(ONO2)3 (trinitrate)

polymer: [C6H7(OH)x(ONO2)y]n where x + y = 3

monomer:

297.1334g/mol (trinitrate)

252.1358 g/mol (dinitrate)

207.1382 (mononitrate)

13.4% nitrogen = 6900m/s >86cm @ 150g

Nitrostarch is a bit useless now days, but it's still worth mentioning. It was quite a big part of history, as it was the filler of a majority of the grenades used in world war two. It is a powerful explosive when it reaches a high enough nitrogen content, but something like nitroglycerin is easier and more powerful. The final product can be any number of shades from white to brown, it just depends on how you treated it during purification. It's most often a tan colored powder however. It's made by the action of nitric acid on starch. Starch is a mixure of amylose, and amylopectin, however both amylose nitrate and amylopectin nitrate are the same. They have the same monomers, both nitrate and non-nitrate, but amylopectin is an unstructured polymer while amylose is a straight chain type polymer. Since it is a nitrated polymer, each monomer (one section of the polymer) can have a different degree of nitration done to it. Thus, nitrostarch can only be rated in percent of nitrogen. The highest percentage attainable would be a 14.14% nitrogen content, which is all monomers at the trinitrate. Unfortunately, if you have one dinitrate monomer, it would take 21 trinitrate monomers to keep you in the 14% range of nitrogen. If you have one mononitrate, you need 52 trinitrate monomers to keep you in the 14% nitrogen range. Obviously, the more nitrogen, the more powerful. The synthesis is calculated for the trinitrate, but obviously conditions will not allow that with mixed acids.

3HNO3 + C6H10O5 ----> C6H7O2(ONO2)3 + 3H2O

Materials
Equipment
Corn Starch 600ml beaker
70% Nitric Acid Icebath
>94% Sulfuric Acid Thermometer
Sodium Bicarbonate Hotplate
  Filtering equipment

 

 

The following synthesis requires patience. Proper nitrostarch can not be produced quickly, and you can't simply "whip up" some nitrostarch. The actual synthesis doesn't take a whole lot of energy, but purification and synthesis combined will take some time. Luckily, it can be made in great quantities, just multiply the values by 10, 20, even 100 if you're adventurous and have the precursors. Of course, you will notice quite a bit of water is used compared to the amount of produced produced during purification. When you scale up the synthesis, you do not need this much water. The general rule would be 4 times the total volume of acid, for total volumes less than 250ml. Use 2-3 times the total volume of acid for total volumes greater than 250ml.

Prepare an icebath, and place a 600ml beaker in it. Restrain it with any means neccessary. In a graduated cylinder, pour 15ml of the nitric acid. To this, add 30ml of sulfuric acid - some heat will be generated. Pour this into the 600ml beaker quickly but carefully (this is to ensure a homogenous nitration mixture). Weigh out 10grams of corn starch, or similar starch. Pour this through a fine screen into the nitration mixture. The screen can be any kind of food seive or strainer, just as long as you break up the lumps of cornstarch. It's okay to add it all at once, the reaction does not progress quickly or generate substantial heat. Begin stirring, while monitoring the temperature. If the temp of the reaction approaches 15C, stop stirring for a second. You wont get a runaway, but a better product forms at colder temperatures. Continue stirring for 15minutes total. At this point, you may walk away and do something else. Check back every 10 to 15 minutes to give it a good 1 minute long stir. After an hour and a half, to 2 hours, add distilled water to the 400ml mark on the 600ml beaker. This is to precipitate the nitrostarch and make it easier to remove the acids.The mixture will be quite cloudy as any disolved nitrostarch precipitates.

Let all the nitrostarch settle to the bottom, this shouldn't take longer than 10-20 minutes. You will be left with a slightly cloudy solution above a layer of white-yellow powder (your nitrostarch). Decant the liquid off into a waste container (or sink, it's not harmful for the environment if flushed with copious amounts of water). Add more distilled water, again bringing it to the 400ml mark. Let it settle once again, and like before, you'll be left with a cloudy solution atop a white-yellow powder. Decant the fluid off into waste container or sink. This is to remove the majority of any remaining acids. Once again, fill to the 400ml mark with distilled water. This time, begin heating it with a hotplate.

Add 2-5ml of nitric acid to this. Bring it to a boil and hold it there for 10 minutes. This will hydrolyze any sulfate isomers that formed from the sulfuric acid and produce an all around better product. After 10 minutes, remove it from the hot plate (carefully) and set it somewhere cool but not cold. Within 5 minutes, the nitrostarch should settle to the bottom and you'll be left with a clearer looking solution above it. It is imparative that you decant the solution while it is still clear, as this is the step that removes the vast majority of unreacted starch. Now, add distilled water to the 300ml line. Bring it to a boil, now check if acid is present with blue litmus paper. Add sodium bicarbonate until the blue litmus paper shows no acid. Don't continue adding sodium bicarbonate once there is no acid present, because it will keep reacting. Be sure to check the litmus paper, because as I said before, the bicarbonate will still react and produce foam even when the acid has been neutralized. Remove this from the hot plate and place it on a cool but not cold surface. Again, it should only take 5 minutes for the nitrostarch to settle to the bottom, at which point you can decant the fluid off.

Then add water to the 300ml mark and wait 10-15 minutes for the starch to settle to the bottom. Once it has, you may begin filter the product out. Use a wash bottle with distilled water to rinse all of the product into the filter. Flush once with distilled water, then press dry the product once it has stopped dripping. You may dry it under a heat lamp with no adverse affects. The theoretical yeild is 18.33g of nitrostarch. The yeild I got was 10.7grams, which is a 58.4% yeild. Obviously I'll be revisiting this to improve yeilds.

PICS

Nitrostarch yeild - Here is a picture of 10.7g of dry nitrostarch.