Synthesis of PGDN
PGDN, an acronym for propylene glycol dinitrate, is an energetic derivative of glycerin with chemical, physical, and explosive properties similar to nitroglycerin. Propylene glycol, the main precursor to PGDN, is found in some anti-freezesit is the active ingredient in ecological brands because of its low toxicity to animals. PGDN is safer to handle than nitroglycerin by a factor of tenit sacrifices some explosive power, but the gain in stability more than offsets the loss of power. The increased stability of PGDN vs. nitroglycerin means it can be stored for long periods of time, and it is frozen only with difficulty. Frozen nitroglycerin can be especially dangerous. PGDN can gel guncotton for use in smokeless powders, like nitroglycerin, and all this without the nitro headaches.
- isopropylene nitrate
- methylglycol dinitrate
- methylnitroglycol
- NSC 62614
- 1,2-propanediol, 1,2-dinitrate
- 1,2-propanediol, dinitrate (8CI,9CI)
- propylene dinitrate
- 1,2-propylene glycol dinitrate
- propylene glycol dinitrate
- propylene nitrate (6CI,7CI)
Prepare an acid mixture of 16 mL of 96% sulfuric acid and 14 mL of 90% nitric acid in a 100-mL beaker. Place the beaker into a salt-ice bath and cool it to 10 °C. Once cool, slowly add 9.6 mL of propylene glycol dropwise, with a pipette or burette, while stirring. Regulate the rate of addition to keep the temperature between 10-15 °C. The addition should take about 30 minutes. Do not let any liquid splash onto the walls of the beaker, it can oxidize and cause dangerous decomposition, if any red fumes are observed, dump the contents of the beaker down the drain with plenty of cold water. If at any time the temperature rises suddenly, or the temperature climbs over 20 °C, immediately dump the reaction. Having a bucket of ice water to dump the beaker into is advisable. After the addition, continue stirring for an additional 10 minutes, and maintain the temperature. Pour the contents of the beaker into a separatory funnel and allow it to stand for 15 minutes. The lower layer should be acid waste, draw it off and keep for further extraction. Leave the upper layer in the funnel, add an equal volume of cold water and gently shake for 1 minute. Allow the mixture to separate, the lower layer will be PGDN. Draw off the lower layer into a beaker, and pour the wash layer into a separate beaker. Add the PGDN back into the separatory funnel and wash twice more, add each wash layer to the beaker containing the first wash. Next, wash the PGDN with 5% sodium carbonate solution in the separatory funnel, add each of the carbonate washes to the beaker of the previous water washes. Test each of the carbonate washes for its pH, keep washing with carbonate solution until the wash is alkaline. Once the carbonate wash is alkaline, wash the PGDN with more water until the washes are neutral. The PGDN after the final wash may be cloudy from water still in it. Pour the PGDN onto an evaporation dish and let it set for 3-6 hours, the water should evaporate.
To get more PGDN from the waste acid, add the acid to a separatory funnel and extract with several portions of chloroform. Combine all of the chloroform extractions and use it to extract the PGDN from the water and carbonate washes. Wash the chloroform until its pH is neutral. Allow the chloroform to evaporate, leaving behind PGDN which can be combined with the rest. 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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