не, 20 мин мало, все что знаю скажу: ацетилироют до ДИацетилморфина долго и с избытком ангидрида
если передержишь то не испортишь, ну очень мало вероятно что испортишь
вообщем если есть силы на небольшой эксперимент, то вперед
если по молям высчитывать, то самого ангидрида надо вообще малое кол-во, но в реале хз как оно, тут тока если искать старательно методы, или побывать на подпольном заводе по изготовлению качевственного героина
ну что тут можно
из википедии(там чтото про 6 часов и 85градусов говорица, обльше разбирать лень):
Manufacturing
Heroin is produced for the black market through opium refinement process - first, morphine is isolated from opium. This crude morphine is then acetylated by heating with acetic anhydride. Purification of the obtained crude heroin as a hydrochloride salt provides a water-soluble salt form of white or yellowish powder.
Crude opium is carefully dissolved in hot water but the resulting hot soup is not boiled. Mechanical impurities - twigs - are scooped together with the foam. The mixture is then made alkaline by gradual addition of lime. Lime causes a number of unwelcome components present in opium to precipitate out of the solution. (The impurities include the useless alkaloids, resins, proteins). The precipitate is removed by filtration through a cloth, washed with additional water and discarded. The filtrates containing water-soluble calcium salt of morphine are then acidified by careful addition of ammonium chloride. This causes the morphine to precipitate. The morphine precipitate is collected by filtration and dried before the next step. The crude morphine (which makes only about 10% of the weight of the used opium) is then heated together with acetic anhydride at 85 °C (185 °F) for six hours. The reaction mixture is then cooled, diluted with water, alkalized with sodium carbonate and the precipitated crude heroin is filtered and washed with water. This crude water-insoluble free-base product (which by itself is usable, for smoking) is further purified and decolourised by dissolution in hot alcohol, filtration with activated charcoal and concentration of the filtrates. The concentrated solution is then acidified with hydrochloric acid, diluted with ether and the precipitated white hydrochloride salt of heroin is collected by filtration. This precipitate is the so-called "no. 4 heroin", the standard product exported to the Western markets. (Side-product residues from purification or the crude free base product are also available on the markets, as the "tar heroin" - a cheap substitute of inferior quality.)
The initial stage of opium refining - the isolation of morphine - is relatively easy to perform in rudimentary settings - even by substituting suitable fertilizers for pure chemical reagents. However, the later steps (acetylation, purification, precipitation as hydrochloride) are more involved - they use large quantities of dangerous chemicals and solvents and they require both skill and patience. The final step is particularly tricky as the highly flammable ether can easily ignite during the positive-pressure filtration (the explosion of vapor-air mixture can obliterate the refinery). If the heroin does ignite, the result is a catastrophic explosion.
:lol: 
