Explosive Theory

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Saturday, October 07, 2006

Sorbitol and Mannitol Hexanitrate!!!

4) Sorbitol Hexanitrate
This is very similar to Mannitol Hexanitrate (see below). Shock sensitive, small quantities burn rapidly if ignited. This procedure will produce a sticky liquid product, which is actually a mixture of nitrates. A solid product can be obtained by dissolving it in ethanol, and adding an equal volume of cold water to precipitate it. This will be pure Sorbitol Hexanitrate.
You will need:
5g of sorbitol,35mL of 70% nitric acid,70mL of 90% sulphuric acid,Distilled water,Sodium bicarbonate,Urea,Two 250mL beakers,A 500mL beaker,A thermometer,A hot water bath,A dropping pipette,An ice bath.
1) Put the sorbitol and nitric acid in a 250mL beaker, and cool it to 5*C in the ice bath.2) Stir it until all the sorbitol has dissolved.3) Slowly add the sulphuric acid, while stirring, making sure that the temperature does not rise above 10*C.4) After all the sulphuric acid has been added, dump the reaction into the 500mL beaker, containing 200mL of distilled water.5) Warm the water/acid/product mixture to 40*C to melt the Sorbitol Hexanitrate. It will settle to the bottom.6) Using the pipette, suck up the prodcut while still warm, and add it to the other 250mL beaker, containing 100mL of water and 10g of sodium bicarbonate.7) Warm it to 40*C, and stir it for 10 minutes.8) Add 5g of urea and stir it for a further 10 minutes.9) Suck up the Sorbitol Hexanitrate with the pipette, and let it dry in a warm place overnight.-=-=-=Mannitol Hexanitrate
"This is a different isomer of Sorbitol Hexanitrate, but this one is more widely used, as a base charge in blasting caps. This procedure produces a white powder, and yields seem to be higher. Lead block expansion for this explosive is a whopping 560 cm3, almost as high as Glyceryl Trinitrate! VoD is 7000 m/s, density is 1.60 g/cm3, relative brisance is 0.96 under these conditions.
To make it, use the procedure for Sorbitol Hexanitrate above, but use mannitol instead of sorbitol (duh...), use a mixture of 6mL of 70% nitric acid, 27g of potassium nitrate and 14mL of 98% sulphuric acid instead of the nitric acid, and use 30mL of 98% sulphuric acid. Omit the step in which the Sorbitol Hexanitrate is melted. Simply filter off the Mannitol Hexanitrate and recrystalise it from ethanol after washing and drying the crude product."------------------------However when 20 grams of mannitol which was ground very fine (beyond any crystalline make-up via ball mill) it was mixed into 130gr (72ml @ 93&) H2SO4 @ 20 C via magnetic stirrer until completely in solution. Material was stirred until transparent. Care was taken to prevent carbonization.The Mannitol-H2SO4 solution was then placed into a refrigerator to maintain temp of 15 C.A solid nitrate (KNO3) was mixed with H2SO4 in a separate beaker: 60gr KNO3 into 182 gr (100ml) H2SO4. This was prepared at 60C and stirred until clear solution was achieved. This solution of mixed acids was then placed in a refrigerator and both solutions brought to 15 C.The mixed acid solution was placed on a magnetic stirring device and into it was introduced the mannitol / H2SO4 solution in small portions (drop wise, 3 drops per second).The temp of 0-15 C was maintained for this addition & was achieved by using an ice and ethylene glycol ("anti-freeze") bath. During the addition the mixture became quite thick. At that juncture 50 ml of 70& HNO3 was added in two portions. The HNO3 being previously chilled to 15 C having been in a refrigerated environment. The solution continued to thicken and was withdrawn from the ice bath and stirring (total time 30 min, stirring) and placed covered in refrigerator. Allowed solution to remain in refrigerator at 15 C. After 2 hours solution solidified and appeared to have no mobility but appeared as a solid.
The nitration is reputed to proceed unevenly and due to the mass created by the forming crystals within the mixed acids this may certainly be true. That is a significant reason to add the liquid HNO3; to maintain the ability to stir the solution as well as add to the nitration level. Overall the nitration is slow but the initial reaction is such that a thick mass (of crystals) is created quite soon after the introduction of the mannitol / H2SO4. There will be both hexanitrate and pentanitrate within the initial nitration. It has been noted that the appearance of needle crystals as opposed to other shapes is indicative of hexanitrate and this should be the target of production after re-crystallization from alcohol. The re-crystallization if carried out a 2nd time will result in a granular formation which is ideal for utility usage and is not a reflection of pentanitrate formation at that time.
Random observations: After addition of mannitol / H2SO4 there appeared to be particulate matter forming in solution and would stick to side of beaker when tipped. At no time did solution appear clear. As soon as mannitol was introduced into mixed acids there appeared to be particulate matter in solution. NOx gas will evolve @100C after one hour. Solubility: Very sol in hot EtOh, MtOh, Acetone. Best is EtOh Acetone exhibits negative vapor pressure. Stability is achieved by addition of Na Salicylates. Also refer to US Patent 1751438 (Sorbitol Hexanitrate) regarding material's need for temp to maintain above a certain level to maintain solidity, etc.

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