Emulsion Extraction apparatus

Note. (1) Batchwise extraction leads to the formation of stable emulsions which frequently take several days to break. When filling the continuous extraction apparatus, care should be taken to avoid forming an emulsion. 

An ethereal solution of 1 kg of cholesterol is added to 100 kg of a 10% aqueous-alcoholic horse extract. The resulting emulsion is stirred at 90°C for 1 hour, while the ether is distilled off. The water insoluble saponin-cholesterol precipitate is centrifuged and washed with cold water until the wash water is colorless. The precipitate is air-dried at room temperature. The resulting dust-fine powder is extracted with ether in a Soxhlet apparatus for 10 days. The residue is treated with 20 kg of methanol and the undissolved material is filtered off. The yellowish methanol solution is treated with activated charcoal until it is colorless. The methanol is distilled off in a vacuum, and the residue is dried over phosphorus pentoxide in a vacuum not exceeding 1 mm Hg. The yield of pure sodium escinate obtained thereby is about 0.8 kg (8%). 

Because of the formation of emulsions, the liquid-liquid extraction (LLE) of nonionic surfactants, e.g., APEO, is restricted to these less surface-active metabolites, i.e., APEO with one to three ethoxy units, APEC, and AP. Noncontinuous LLE of water samples with methylene chloride using a separatory funnel has been applied for NP and NPEO (one to three ethoxy units). In addition, an ultrasonic bath has been shown to be suitable for the LLE of APEOs and AEOs form water samples.Continuous LLE (percolation) has been successfully used for concentration of short-chained APEO and AP too. Steam distillation/solvent extraction using an apparatus designed by Veith and Kiwus " is a sophisticated method of concentrating steam-distillable AP and APEO (one to three ethoxy units) from water samples.AEOs have been efficiently extracted by combination of reflux hydrolysis with sulfuric acid and steam distillation with a Karlsruhe Apparatus. ... 

In a complex apparatus, Gimesch and Schneider [30, 119] studied the suspension polymerization of vinyl acetate. Their procedure involved equipment which automatically added tempered water to the reacting system as heat was evolved as a result of the polymerization process. Thus they maintained isothermal reaction conditions. The rate of reaction could be followed by recording the water uptake of the equipment with time. The heat of polymerization was also determined (found to be 23 kcal/mole which was considered a satisfactory check of the literature value which is scattered around 21.4 kcal/mole). From this work, a somewhat different mechanism of the suspension polymerization process emerges than the widely accepted concept of the water-cooled bulk polymerization of small particles. It was noted that with an increase in the initiator concentration, there was the expected increase in polymerization rate. With increasing stirring rate, the rate of polymerization decreased. Along with the suspension polymerization, there was always a certain amoimt of imdesirable emulsion polymerization. It was postulated that in the process, free radicals, formed in a monomer drop may be extracted into the aqueous phase where they may act on dissolved vinyl acetate by kinetic processes unique to this system and different from the conventional mechanism of suspension polymerization. 

Swelling of the emulsion usually does not react equilibrium. Due to the large difference between the osmotic pressures of the external and internal aqueous solutions, the swelling of extracting emulsions may be considerable. Therefore optimization of the residence time of the extracting emulsion in the apparatus to concentrate the target substance to the maximum extent is important. 

Monomer (and hydrophobe - in miniemulsion cases) was mixed with surfactant and AIBN, and the whole mixture was stirred at room temperature for 1 h. The amount of SDBS in emulsion polymerization without SWNTs is 6mM (5 cmc). After 1 hour of stirring, the flask was sonicated for 60 s and, immediately after sonication, the mixed solution was stirred at 65°C for 14 h. Water was evaporated and the solid polymer remaining was extracted with isopropanol using a Soxhlet apparatus to remove hexadecane and surfactant. The resulting product was then dried to remove isopropanol. The oil/water phase mass ratio is 10/90 in both types of reactions. In... 

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