|petrin acrylate||molecular mass
Petrin acrylate is the smaller version of pentaerythritol trinitroacrylate, or trinitroxypentaerythritol acrylate. Another name is pentaerythritol trinitrate monoacrylate. This substance is primarily used as a rocket propellent, so I guess it is not really an explosive at all. This will burn very well and will probably explode under the proper conditions, still, it seems to me that PETRIN, the main precursor, would make a more valuable explosive instead of acrylating it. Of course, one may need a suitable rocket propellent. This substance also acts as a very effective binder, a double plus for solid rocket fuels.
|acrylic acid||Erlenmeyer flask|
|acrylyl chloride||graduated cylinder|
Prepare a mixture of a small quantity of trifluoroacetic anhydride and glacial acrylic acid into an Erlenmeyer flask of suitable volume. Cool the mixture to 10-15 °C, then slowly add a small amount of pentaerythritol trinitrate (Petrin), with a pipet or buret, while maintaining the temperature. Although I have no data for exact volumes, I suggest using equal volumes of all chemicals. After 1 hour, drown the mixture with water to precipitate the product. Filter the product to collect the crystals of petrin acrylate. Dissolve the crystals in methyl alcohol, the product is then allowed to crystallized over a period of 16 hours at 0 °C, then washed with water to remove any trace of acidity. The final pure product is dried under vacuum to remove traces of solvent. The yield should be about 74%, an alternative process using N,N-dimethylaniline and acrylyl chloride instead of trifluoroacetic anhydride and acrylic acid with yields of 46% is possible. The high cost and difficulty using trifluoroacetic anhydride justifies the lower yield. You will need a graduated cylinder for measuring liquids, and a thermometer to monitor the temperature.
Although petrin acrylate can be used as a propellent alone, the addition of an oxidizer can make it more powerful. A typical propellent composition consists of: 34.3% petrin acrylate as a binder, 11.8% triethylene glycol trinitrate as a plasticizer, 2.9% glycol diacrylate as a crosslinker, 51.0% ammonium perchlorate as an oxidizer, and 0.014% hydroquinone as a polymerization inhibitor. This composition is reported to have a specific impulse of 238 lb-sec/lb at a density of 1.3 g/mL. Plain petrin acrylate has a specific impulse of 214 lb-sec/lb and a burning rate of 0.2 inch/sec.
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