Special Extraction Apparatus

An apparatus which allows for continuous extraction and removal of hash oil is depicted in figure 18. The oil is occasionally tapped from the lower container and from time to time the device must be cooled and the marijuana or hashish in the upper container changed. Many variations are possible several are noted in the following comments from the DEA. 

The following comments were made by the DEA (Drug Enforcement Administration) in 1973  

There are many ways to produce hashish oil, but the basic principle used by most clandestine operators is similar to that of percolating coffee. A basket filled with ground or chopped up marijuana 

One seizure revealed a veritable Rube Goldberg machine consisting of a boiler, a heat exchanger, a vacuum assembly and other components (with parts list, instructions and assembly methods) for a sophisticated hashish oil apparatus which was scheduled to be shipped to the Middle East. 

Hashish laboratories have been seized in the middle and western United States, Mexico, and South America. Hashish oil itself has been found in several parts of the United States, in Central and South America, and in Europe. Most of the hashish oil that has been confiscated originated in India or Afghanistan and was shipped via commercial freight directly to the United States or Canada for forwarding. Thus far the senders and laboratory operators have usually been U.S. citizens. 

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The mixture is transferred (Hood) (Note 5) while still hot to a a fluted filter paper in a 20-cm. glass funnel, leaving behind as much mercury as possible (Note 2). The funnel is made part of a special extraction apparatus as described in Org. Syn. 2, 49. The mercury diphenyl is extracted with 600 cc. of boiling benzene for about ten hours (Note 3). 

Separating funnels for batch extraction special glass apparatus for continuous extraction automatic shakers used for discontinuous counter-current distribution. 

In the Amoco process, p-xylene is oxidized at 200 °C under 15-20 atm in acetic acid and in the presence of a catalyst consisting of a mixture of cobalt acetate (5% weight of the solution), manganese acetate (1%) and ammonium bromide. Owing to the highly corrosive nature of the reaction mixture, special titanium reactor vessels are required. One of the main difficulties of this process is to remove the intermediate oxidation products such as p-toluic acid or p-carboxybenzal-dehyde which contaminate TPA obtained by precipitation from the reaction medium. A series of recrystallization and solvent extraction apparatus is required to obtain fiber grade TPA with 99.95% purity. The overall yield in TPA is ca. 90% for a 95% conversion of p-xylene. 

It is not-usually necessary to determine the carbon dioxide in beer, since the external characters of the latter generally indicate if the gas is present in sufficient quantity. When, however, the determination is necessary, loss of gas during the extraction of the beer must be avoided. To this end, the vessels may be well cooled before they are opened, or special automatic extraction apparatus may be employed by means of which the beer is transferred directly, without loss of carbon dioxide, from the cask or bottle to the flask used in the determination. 

To take away the mystery from the word supercritical, it should be recognized that a supercritical fluid can be used like any other solvent for maceration and percolation processes. The only restriction is that it must be handled under high pressure, a fact that requires a special and expensive design of the extraction apparatus. This obvious disadvantage however is compensated by many benefits as demonstrated below. Supercritical C02-extraction of botanical materials is today a well-developed and reliable procedure applied on an industrial scale for about 20 years. The equipment is available turn-key from various suppliers in multi-purpose design or tailor made for special applications. 

Different analytical techniques have been developed to extract and measure iodine concentration from the soil. The reduction of Ce (IV) by As (m) catalyzed by iodine can be used to determine the low concentration of iodine in plant and soil samples. The sample preparation requires a specialized combustion apparatus and trapping systems for iodine. For plant samples and biological materials, halogen extraction using TMAH under mild conditions has proved to be effective (Knapp et al., 1998). 

In the following, essential features of important designs of extraction apparatus are described in tabular form. Design considerations are included. For further detailed treatment and special design considerations of these extractors, literature is cited. 

Alternatively, polymer (5 g) is weighed into an extraction thimble, the diethylether (130 ml) is added, followed by extraction for 3 hours. The system is cooled to room temperature and the solvent is drained into a 250 ml flat bottom flask. The extraction thimble and extraction apparatus are rinsed with 25-30 ml of extraction solvent and drained into a 250 ml flask (a turbid solution due to the precipitation of extracted polyolefin may be seen upon cooling, however, this is not uncommon nor should any special precautions be taken). The extraction solvent is removed by evaporation to leave a dry residue. 

Another twelfth of dephlogisticated air was then added and a second explosion made, and so on for six explosions. Then another twelfth of dephlogisticated air was added and inflammable air allowed to enter again as far as it would. This time, owing to the heat of the globe and the accumulation of impurities, only five explosions could be made. In all, 137 explosions were made the globe was allowed to cool, and the gas extracted for subsequent examination by a special pneumatic apparatus adapted to the pump. The operation was then begun anew. 

Solvent extraction Solvent extraction (SE) is used as a means of sample pre-treatment or clean-up to separate analytes from matrix components that would interfere with their detection or quantitation (Topic A4). It is also used to pre-concentrate analytes present in samples at very low levels and which might otherwise be difficult or impossible to detect or quantify. Most extractions are carried out batchwise in a few minutes using separating funnels. However, the efficient extraction of solutes with very small distribution ratios (<1) can be achieved only by continuously exposing the sample solution to fresh solvent that is recycled by refluxing in a specially designed apparatus. 

By the addition of strong lOM sodium hydroxide, nitric acid, or sodium nitrate, adjust the solution so that a total aqueous voliune of 10 ml. will be 1 to 3N In hydrogen Ion and 2 to In nitrate Ion. For almost neutral solutions, 2 ml. of concentrated nitric acid will give the correct concentrations for a 10-ml. aqueous volume. Adjust the total volume to 10 ml. Up to 12 ml. of aqueous solution can be eheiken with 5 or 10 ml. of extractant In the apparatus without undue splashing. If the total aqueous volume Is greater than 12 ml. after adjusting the acidity and nitrate content, perform the extraction In a separatory funnel Instead of the special extraction vessel. 

It may be desirable to try to keep the sample exposed to fresh extracting solvent as much as possible during the extraction in order to maximize the transfer to the liquid phase. This may be accomplished by pouring off the filtrate and reintroducing fresh solvent periodically during the extraction and then combining the solvent extracts at the end. There is a special technique and apparatus, however, that have been developed, called the Soxhlet extraction, which accomplish this automatically (previously described... 

The enzyme urease was discovered in soybeans by Takeuchi in 1909 it catalyzed the conversion of urea to ammonium carbonate. Jack beans were another excellent source of the enzyme. Jack bean powder could be stored for considerable periods and very active, soluble, urease extracted. After the action of urease, the ammonia could be estimated colorimetrically by Nesslerisation or titrimetrically. The Conway diffusion apparatus was specially developed for the estimation of urea titrimetrically and remained in use into the 1950s. 

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