Opium lime methods

The lime method involves the addition of calcium hydroxide (lime) to opium in water. This completely extracts morphine and codeine and partially extracts thebaine and papaverine. Ammonium chloride, alcohol, and ether are added and the solution filtered. Morphine precipitates while thebaine and papaverine remain in the ether layer. The crude morphine is purified by refluxing in dilute sulfuric acid in the presence of charcoal. The final morphine base is precipitated as an off white material by addition of ammonium hydroxide. 

Chemistry The first step toward making heroin is extracting morphine from the opium plant extract. The lime method, introduced in Chapter 6, Section 6.3.3, and shown in Figure 6.8, is a common extraction protocol that yields morphine... 

Lime method A procedure used to extract morphine from opium using lime (calcium hydroxide) to make extract basic... 

Official lime methods depend upon the complete extraction of the opium by a single maceration with lime water and the quantitative precipitation of the morphine directly from the lime with ammonium chloride. Since some of the water used for extraction is retained by the marc it is never possible to examine the entire extract and so the morphine must be determined in an aliquot portion of it. In the case of the P.P. it is assumed that 52 ml will contain five-eighths of the morphine from the entire sample of opium, but this can only be an approximation since the increase in volume of the opium extract due to moisture and extractives from the opium will vary from sample to sample. Some methods, including that prescribed by the PA./., allow for these variations by determining extractive matter and moisture at the same time as morphine on a given sample of opium. 

Various modifications, notably by Van Pinxteren and Smeets, have improved the method. These authors modified the procedure so as to include a lime-manganous chloride extraction and by so doing were able to obtain a precipitate w hich gave a purity of 98 to 99 per cent on titration and which was relatively free from methoxyl groups, indicating a low contamination with other opium alkaloids. 

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