decomposes at 130 °C
Petrin is an acronym for pentaerythritol trinitrate. One of the biggest uses for Petrin is to make petrin acrylate, a good propellant and binder in one, out of it. Petrin is also used as an intermediate in a number of other explosive nitrate esters. It has been used as a component of propellent binders, a plasticizer for slow burning propellents, a binder for cloud-seeding pyrotechnics, a gelling agent for nitrocellulose, and even in medicine as a vasodilator. There is not a lot of explosive data on Petrin because most scientists seem more concerned with what they can make from it instead of using it as is. What data there is comes from the original German patent for its synthesis back in 1937, back when the Germans were happy, simple country folk with religious issues and a Christian superiority complex.
|methylene chloride||crystallization dish|
|nitric acid||graduated cylinder|
|sulfuric acid||stirrer/stirring rod|
There are many different methods concerning the synthesis of Petrin, but perhaps the best is an anonymous publication from 1971. This reaction creates both Petrin and PETN. Prepare a mixture of pentaerythritol and 100% nitric acid in a beaker chilled to 0 °C in a salt-ice bath. Add to this mixture some methylene chloride solvent and mix well. Now add 2 mL of 100% sulfuric acid for every 8 mL of nitric acid added. The temperature must stay at 0 °C throughout the reaction. I do not have data concerning exact volumes, I suggest using several times the volume of mixed acid to the volume of pentaerythritol. After the sulfuric acid has been added, remove the methylene chloride by decanting it off the top with a pipet. Add more fresh methylene chloride and remove it after a few minutes of mixing. Continue the solvent addition and removal several times during the reaction. Combine all of the solvent extracts and neutralize them with ammonium carbonate until neutral to litmus paper. The neutralized methylene chloride can be distilled to concentrate the volume of Petrin solution while recollecting the methylene chloride. The remaining Petrin residue can then placed in a crystallization dish to evaporate the rest of the way. You could also use vacuum drying to speed the process along. Adding water to the remaining acid mix should precipitate the PETN that formed, further purification instructions can be found on that page. You will need a graduated cylinder for measuring liquids, a stirring rod or magnetic stirrer for mixing, and a thermometer to monitor the temperature.
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