A third choice is also possible for

A third choice is also possible for use as a crystallization solvent.
This is mineral spirits available from hardware stores in the paint
department. Mineral spirits are roughly equivalent to the petroleum ether
or ligroin commonly seen in chem labs. Those brands which boast of low odor
are the best choice. Before using this material it is best to fractionally
distill it, and collect the lowest boiling point half of the product. This
speeds crystal drying. Since the choice of mineral spirits eliminates ether
from the supply loop, the clandestine operator may well go this route.
Toluene is also an acceptable solvent.

With the solvent of his choice, the chemist rinses the insides of the
condenser, vacuum adapter and 250 ml flask to get out the methamphetamine
clinging to the glass. This rinse is poured in with the product. Solvent is
added to each of the Erlenmeyer flasks until the volume of liquid is 300
ml. They are mixed by swirling.

A source of anhydrous hydrogen chloride gas is now needed. The chemist
will generate his own. The glassware is set up as in Figure 10. He will
have to bend another piece of glass tubing to the shape shown. It should
start out about 18 inches long. One end of it should be pushed through a
one-hole stopper. A 125 ml sep funnel is the best size. The stoppers and
joints must be tight, since pressure must develop inside this flask to
force the hydrogen chloride gas out through the tubing as it is generated.



Into the 1000 ml, three-necked flask is placed 200 grams of table salt.
Then 35% concentrated hydrochloric acid is added to this flask until it
reaches the level shown in the figure. The hydrochloric acid must be of
laboratory grade.

Some concentrated sulfuric acid (99-98%) is put into the sep funnel and
the spigot turned so that 1 ml of concentrated sulfuric acid flows into the
flask. It dehydrates the hydrochloric acid and produces hydrogen chloride
gas. This gas is then forced by pressure through the glass tubing.

One of the Erlenmeyer flasks containing methamphetamine in solvent is
placed so that the glass tubing extends into the methamphetamine, almost
reaching the bottom of the flask. Dripping in more sulfuric acid as needed
keeps the flow of gas going to the methamphetamine. If the flow of gas is
not maintained, the methamphetamine may solidify inside the glass tubing,
plugging it up.

Within a minute of bubbling, white crystals begin to appear in the
solution. More and more of them appear as the process continues. It is an
awe-inspiring sight. In a few minutes, the solution becomes as thick as
watery oatmeal.

It is now time to filter out the crystals, which is a two-man job. The
flask with the crystals in it is removed from the HC1 source and
temporarily set aside. The three-necked flask is swirled a little to spread
around the sulfuric acid and then the other Erlenmeyer flask is subjected
to a bubbling with HC1. While this flask is being buWled, the crystals
already in the other flask are filtered out.

The filtering flask and Buchner funnel are set up as shown in Figure
11. The drain stem of the Buchner funnel extends all the way through the
rubber stopper, because methamphetamine has a nasty tendency to dissolve
rubber stoppers. This would color the product black. A piece of filter
paper covers the flat bottom of the Buchner funnel. The vacuum is turned on
and the hose attached to the vacuum nipple. Then the crystals are poured
into the Buchner funnel. The solvent and the uncrystallized methamphetamine
pass through the filter paper and the crystals stay in the Buchner funnel
as a solid cake. About 15 ml of solvent is poured into the Erlenmeyer
flask. The top of the flask is covered with a palm and it is shaken to
suspend the crystals left clinging to the sides. This is also poured into
the Buchner funnel. Finally, another 15 ml of solvent is poured over the
top of the filter cake.

Now the vacuum hose is disconnected and the Buchner funnel, stopper and
all, is pulled from the filtering flask. All of the filtered solvent is
poured back into the Erlenmeyer flask it came from. It is returned to the
HC1 source for more bubbling. The Buchner funnel is put back into the top
of the filtering flask. It still contains the filter cake of
methamphetamine crystals. It will now be dried out a little bit. The vacuum
is turned back on, the vacuum hose is attached to the filtering flask, and
the top of the Buchner funnel is covered with the palm or a section of
latex rubber glove. The vacuum builds and removes most of the solvent from
the filter cake. This takes about 60 seconds. The filter cake can now be
dumped out onto a glass or China plate (not plastic) by tipping the Buchner
funnel upside-down and tapping it gently on the plate.



And so, the filtering process continues, one flask being filtered while
the other one is being bubbled with HC1. Solvent is added to the Erlenmeyer
flask to keep their v