Drops, extraction from

The effects of interfacial monolayers on the extraction from drops are particularly striking. Early work showed that traces of either impurity or surface-active additives can drastically reduce extraction rates even plasticiser, in subanalytical quantities dissolved from plastic tubing by benzene, reduces the mass-transfer rate by about ten times by retarding... 

Solving the problem on the interaction of a solid particle, drop, or bubble with the surrounding continuous phase underlies the design and analysis of many technological processes. The industrial applications of such interaction include classification of suspensions in hydrocyclones, sedimentation of colloids, pneumatic conveyers, fluidization, heterogeneous catalysis in suspension, dissolving solid particles, extraction from drops, absorption, and evaporation into bubbles [69, 107, 111, 122,137,478,505],... 

The analysis of many technological processes involving dissolution, extraction, vaporization, combustion, chemical transformations in dispersions, sedimentation of colloids, etc. are based on the solution of the problem of mass exchange between particles, drops, or bubbles and the ambient medium. For example, in industry one often deals with processes of extraction from drops or bubbles or with heterogeneous transformations on the surface of catalyst particles suspended in a fluid. The rate of extraction and the intensity of a catalytic process to a large extent are determined by the value of the total diffusion flux of a reactant to the surface of particles of the disperse phase, which, in turn, depends on the character of flow and the particle shape, the influence of neighboring particles, the kinetics of the surface chemical reaction, and some other factors. 

Drop Diameter. In extraction equipment, drops are initially formed at distributor no22les in some types of plate column the drops are repeatedly formed at the perforations on each plate. Under such conditions, the diameter is determined primarily by the balance between interfacial forces and buoyancy forces at the orifice or perforation. For an ideal drop detaching as a hemisphere from a circular orifice of diameter and then becoming spherical ... 

SG sols were synthesized by hydrolysis of tetraethyloxysilane in the presence of polyelectrolyte and surfactant. Poly (vinylsulfonic acid) (PVSA) or poly (styrenesulfonic acid) (PSSA) were used as cation exchangers, Tween-20 or Triton X-100 were used as non- ionic surfactants. Obtained sol was dropped onto the surface of glass slide and dried over night. Template extraction from the composite film was performed in water- ethanol medium. The ion-exchange properties of the films were studied spectrophotometrically using adsorption of cationic dye Rhodamine 6G or Fe(Phen) and potentiometrically by sorption of protons. 

Drugs and metabolites can be extracted from cultures and urine by adding 2 drops of concentrated HCI to 1 ml of urine for a pH of 1-2. Extract with three 1-ml volumes of diethyl ether (top layer) or methylene chloride (bottom layer). Combine extractions and evaporate with clean, dry nitrogen. Adjust to a pH of 8-10 by adding 250 /zl of 60% KOH to 1 ml of urine. Extract... 

The tip current depends on the rate of the interfacial IT reaction, which can be extracted from the tip current vs. distance curves. One should notice that the interface between the top and the bottom layers is nonpolarizable, and the potential drop is determined by the ratio of concentrations of the common ion (i.e., M ) in two phases. Probing kinetics of IT at a nonpolarized ITIES under steady-state conditions should minimize resistive potential drop and double-layer charging effects, which greatly complicate vol-tammetric studies of IT kinetics. 

When the brine has given its heat to the heat pump it is a few degrees colder on the way back to the rock. The heat extraction from the borehole lowers the ground temperature, but after a few years this temperature drop will reach to a point, a steady state, where it will be restored during the summers. 

The tryptophane is extracted from the aqueous solution by repeatedly shaking in a separatory funnel with 25-cc. quantities of ra-butyl alcohol water is added from time to time to keep the volume approximately constant (Note n). The butyl alcohol extract is distilled under reduced pressure. After the water present has distilled over, the tryptophane precipitates in the distilling flask and may cause bumping. When all water has been removed, as is indicated by non-formation of drops on the side of the condenser, the distillation is stopped, and, after cooling, the tryptophane is filtered off and washed with a little fresh butyl alcohol. Such extractions ami distillations are con-... 

Mishra and Gode developed a direct current polarographic method for the quantitative determination of niclosamide in tablets using individually three different buffer systems, namely Mcllraine s buffers (pH 2.20 8.00), borate buffers (pH 7.80—10.00), and Britton Robinson s buffers (pH 2.00—12.00) as well as 0.2 M sodium hydroxide. The drug was extracted from the sample with methanol, appropriate buffer was added to an aliquot and the solution then polarographed at the dropping-mercury electrode versus saturated calomel electrode at 25°C [36], The resultant two-step reduction waves observed were irreversible and diffusion-controlled. For the quantitative determination, the method of standard addition was used. Niclosamide can be determined up to a level of 5—10 pg/mL. 

Thiophenol.—Benzene sulphochloride (8 g.) is allowed to run in small portions from a dropping funnel into a round-bottomed flask containing 20 g. of finely granulated tin and 50 c.c. of concentrated hydrochloric acid. During the addition of the sulphochloride and until most of the tin has dissolved, the flask, which is fitted with a double neck attachment carrying a reflux condenser, is heated on the boiling water bath. The mercaptan produced is distilled with steam and extracted from the distillate with ether. The ethereal solution is dried over sodium sulphate, the ether is removed by distillation, and the thiophenol which forms the residue is likewise distilled. It passes over as an almost colourless liquid at 173°. 

Handlos, A. E. and Baron, T. A.I.Ch.E.Jl. 3 (1957) 127. Mass and heat transfer from drops in liquid-liquid extraction. 

NMR analysis, the PHA was extracted from freeze-dried cells. For this purpose, 1.0 g freeze-dried cells were stirred in 200 mL of chloroform for 24 hours at 30°C. The extract was filtered to remove cells debris, and the chloroform was concentrated to a volume of about 15 ruL using rotary evaporator. The concentrated solution was then added drop-wise to 150 luL of rapidly stirred methanol to precipitate the dissolved PHA.The precipitated PHA was then recovered by filtration using a 0.45 pm PTFE membrane and dried overnight at room temperature. The purified PHA was dissolved in deuterated chlorofonn (CDCl ) and subjected to H and NMR analyses. 

Provided a sample of DNA can be obtained, a restriction analysis can be carried ont. A match between the restriction fragments from a sample of DNA left at the scene of a crime and that of a snspect is a valnable tool in forensic science. The usefulness of this techniqne is increased enormously by combining it with the polymerase chain reaction, since the amount of DNA extracted from a very small amount of tissue can be increased enormonsly, providing enough for a restriction analysis. Tissne samples as small as a single cell, a hair, a drop of sahva, a piece of dandruff or a smear of semen are snfflcient to prodnce enough DNA. It has produced a revolution in forensic science. However, caution must be applied to interpretation of the results for... 

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