Large-Scale Methamphetamine Manufacture

6.3 Discussion

This is an easy procedure to perform, allowing one to make 400ml of 70% nitric acid in one day. The basic idea is to vacuum distill over the nitric oxide created by the reaction of sulfuric acid with sodium nitrate, condense it into a liquid with dry ice, and then drop it into distilled water to capture and dilute the resulting acid. The final step is to boil off the excess water, leaving about 200ml of very clean acid from each batch. The tricks to making this reaction work are a controllable vacuum source and precision control of the heat source.
Set up the lab jack with the hotplate and pot resting on the top surface. Suspend the empty 2000ml RB flask above the pot with a tri-grip. Position it so the bottom of the flask is clear of the pot. Also make sure that the pot can be raised to a point where the flask will touch the bottom of the pot.
While the flask is bottomed out in the pot, add enough vegetable oil (Wesson Oil works) to reach about 1" from the top rim of the pot. Lower the lab jack, hotplate, and pot. Wipe the 2000ml flask clean with a paper towel and remove. Turn on the hotplate to a medium setting. We wish to heat the oil to 90-100°C and no hotter, so measure it with a candy thermometer and adjust the hotplate setting accordingly. We now have a precision heat source that can be applied and removed very rapidly by raising or lowering the lab jack.
We must now prepare our condenser. Seal off one nipple of the condenser with a short piece of plastic tubing that has been sealed on one end by melting the plastic together. Fill the condenser wall with isopropyl alcohol. Seal off the remaining nipple with another section of plastic tubing. Attach the vacuum takeoff and insert into the tubing. The top end should be positioned so the 24/40 joint is even with the top of the plastic tube. When positioned correctly, stuff a little pink insulation into the bottom opening and seal the bottom end of the tube with duct tape. The vacuum takeoff should be the only thing protruding. Attach the stillhead. Fill the tube with chips of dry ice and seal with a little pink insulation material. One will need to construct some custom supports for the tube-a couple of pieces of wood with "V"s cut into them works nicely, especially if mounted to a bottom plate for rigidity.
Next, pour 300ml of distilled water into the receiver flask and position it with a tri-grip and stand so it rests inside our small plastic bucket when attached to the vacuum takeoff. Add cold water to the bucket, then add crushed ice to keep the solution cool-much heat will be generated as the nitric oxide drips into the distilled water. Add a layer of rock salt on top of the ice to further reduce the temperature.
Add 365ml (685g) of sulfuric acid to the 2000ml RB flask. Then 600g of sodium nitrate is added in small portions while swirling the acid. Do this inside a fume cabinet. There will be no visible reaction. Mount well above the heat source. Assemble all of the glassware and attach the vacuum hose with the bleeder valve open so there is no vacuum. Slowly close the bleeder valve and bring the vacuum down to 25-26"Hg on the vacuum gauge.
One must be aware that excessive heat will cause foaming and the nitric oxide to come over too fast to condense. One should slowly raise the oil pot until it barely contacts the reaction vessel. Be prepared to quickly lower the pot if excessive boiling occurs. Watch the drip-tip of the vacuum takeoff; liquid nitric oxide should drip into the distilled water at a rate of 1 drop per second, maximum. Any faster than this will result in overheating the dilute acid and suck much nitric oxide into the vacuum system. It will take 2-3 hours to complete the reaction. During this time, one must replenish the dry ice supply in the tube. Use a flour scoop to carefully add to the tube. There should be 500-600ml of liquid in the receiver when done.
The next step is to remove the excess water from the acid solution in the receiver. This is done by simply boiling the liquid in a normal distillation setup. Distill over water until the temperature climbs to 118-120°C. What is left in the vessel is very pure, clear 70% nitric acid. Store in a cool dry place that is dark. It will keep for several years.
If one's nitric acid becomes discolored, simply distill it.