Introduction
The key chemical used in the acetylation of morphine to form heroin is acetic anhydride, a colorless, highly combustible liquid with a strong pickle-like odor. Though internationally controlled as a heroin precursor, acetic anhydride also used to synthesize aspirin and chemicals for leather tanning and photography.
Morphine conversion to heroin base
1. Morphine hydrochloride or morphine base is mixed with acetic anhydride (Ac2O) at about three-times the mass of the former in a glass, stainless steel or enamel pot.
2. The pot lid is tied or clamped on with a damp towel for a gasket (a makeshift reflux apparatus), and the mixture is heated at 85 °C (185 °F), avoiding boiling.
Note: you can use glass reactor with reflux condenser.
3. The reaction is heated for about 5 h until all the morphine has dissolved.
4. The pot is opened, and the mixture is a solution of water, acetic acid, and diacetylmorphine (heroin), is cooled to a room temperature.
5. Water is added to the mixture at three-times the volume of acetic anhydride, and the mixture is stirred.
6. A small amount of chloroform is added. The mixture is allowed to stand for 20 min. The chloroform dissolves colored impurities and settles to the bottom of the pot as a red, greasy liquid, and the water layer is carefully poured off.
7. Activated charcoal is added to the mixture (chloroform solution), absorbing solid impurities, which are filtered out repeatedly until the solution is clear.
8. Approximately 2.2 kg of sodium carbonate (soda ash) per kg of morphine are dissolved in hot water, added slowly to the mixture until effervescence stops, precipitating solid heroin base.
9. Heroin base is dried. The heroin base should be a granular, white powder at this point. If still colored (beige or light brown), the base may be re-dissolved in dilute hydrochloric or citric acid, treated with charcoal again, re-precipitated and dried.
10. Alternatively, in some manufacturing regions, the incompletely purified base may be packed and transported for sale (a practice probably typical in Southwest Asia). About 700 g of heroin base will be produced from each kg of morphine.
Additional purification
Optionally, skilled heroin chemists may further purify the base by dissolving it in twice its mass of boiling ethyl alcohol, filtering the solution through a heated funnel into a heated flask. This removes traces of sodium carbonate remaining in the base. The flask is submerged in an ice bath, where it is transformed into a thick white cream. The substance is placed in a pan in a refrigerator with a fan set to blow across the pan to slowly evaporate the alcohol. The paste crystallizes after several hours and is then vacuum filtered. The product, referred to as alcohol morphine base, is re-crystallized heroin base.
Conversion of heroin base to heroin hydrochloride
1. For each kilogram of heroin base (or re-crystallized heroin base), 6.6 L of of ethyl alcohol, 6.6 L of diethyl ether, and 225 mL of concentrated hydrochloric acid are measured out. The base is dissolved by heating with one-third of the alcohol and one half of the acid.
2. Another one-third of the acid is stirred in. Next, the remaining acid is added slowly, dropwise, until the product is completely converted to the hydrochloride salt. This result may be confirmed either by observing that a drop of solution evaporates on a glass plate leaving no cloudy residue or by placing a drop of solution on Congo red paper, observing it turn the paper blue.
3. Once the conversion is complete, the remaining alcohol is stirred in. Then half of the ether is added, and the mixture is allowed to stand for 15 min.
4. As soon as crystals begin to form in the solution, the remaining ether is added at once, stirred, and the the vessel is covered. The mixture becomes nearly solid after an hour.
5. It is then filtered, and the solids are collected on clean filter paper. Wrapped in the paper, the solid is dried on a wooden tray, usually over lime rock, and dried in a desiccator (optionally). The fully dried product, heroin hydrochloride, is a fine white powder, ready for packing and shipping.
