Solvent collector

As evident from Fig. 3.1, continuous still systems essentially comprise of an upright arrangement which obviously takes up much less space as compared to the conventional-horizontal still set-up and a solvent-collector (collecting vessel) that is positioned strategically between the still-pot and the condenser. 

Ihe absorber has interstage solvent collectors and a mist eliminator downstream of the absorption section. The regenerator, which may be trayed or packed, is equipped with a... 

Although phosphine [7803-51-2] was discovered over 200 years ago ia 1783 by the French chemist Gingembre, derivatives of this toxic and pyrophoric gas were not manufactured on an industrial scale until the mid- to late 1970s. Commercial production was only possible after the development of practical, economic processes for phosphine manufacture which were patented in 1961 (1) and 1962 (2). This article describes both of these processes briefly but more focus is given to the preparation of a number of novel phosphine derivatives used in a wide variety of important commercial appHcations, for example, as flame retardants (qv), flotation collectors, biocides, solvent extraction reagents, phase-transfer catalysts, and uv photoinitiators. 

Solid particulates are captured as readily as hquids in fiber beds but can rapidly plug the bed if they are insoluble. Fiber beds have frequently been used for mixtures of liqmds and soluble sohds and with soluble solids in condensing situations. Sufficient solvent (usually water) is atomized into the gas stream entering the collector to irrigate the fiber elements and dissolve the collected particulate. Such nber beds have been used to collect fine fumes such as ammonium nitrate and ammonium chloride smokes, and oil mists from compressed air. 

Otner Collectors Tarry particulates and other difficult-to-handle hquids have been collected on a dry, expendable phenol formaldehyde-bonded glass-fiber mat (Goldfield, J. Air Pollut. Control A.SSOC., 20, 466 (1970)] in roll form which is advanced intermittently into a filter frame. Superficial gas velocities are 2.5 to 3.5 m/s (8.2 to 11.5 ft/s), and pressure drop is typically 41 to 46 cm (16 to 18 in) of water. CoUection efficiencies of 99 percent have been obtained on submicrometer particles. Brady [Chem. Eng. Prog., 73(8), 45 (1977)] has discussed a cleanable modification of this approach in which the gas is passed through a reticulated foam filter that is slowly rotated and solvent-cleaned. 

A small amount of collector (surfactant) or other appropriate additive in the liquid may greatly increase adsorption (Shah and Lemlich, op. cit.). Column performance can also be improved by skimming the surface of the liquid pool or, when possible, by removing adsorbed solute in even a tenuous foam overflow. Alternatively, an immiscible liquid can be floated on top. Then the concentration gradient in the tall pool of main hquid, plus the trapping action of the immiscible layer above it, will yield a combination of bubble fractionation and solvent sublation. 

Any type of fraction collector with a drop counter will do. When the solvent is volatile, attention has to be paid so that the solvent does not dry from the concentrated eluent at the tubing vent. 

A switching valve (low pressure) may be used to divert the eluent from the detector to the fraction collector as soon as the polymer is detected. Another switching valve can be used to select the polymer solution or the solvent for introduction into the pump. 

Figure 2, Block diagram of a liquid chromatograph. A, solvent reservoir B, filter C, pump D, pulse dampener (optional) E, pre-column (used only in liquid-liquid chromatography) F, pressure gauge G, infector H, column I, detector J, fraction collector K, recorder or oth readout device.

Fignre 27.3 shows a typical spectroelectrochemical cell for in sitn XRD on battery electrode materials. The interior of the cell has a construction similar to a coin cell. It consists of a thin Al203-coated LiCo02 cathode on an aluminum foil current collector, a lithium foil anode, a microporous polypropylene separator, and a nonaqueous electrolyte (IMLiPFg in a 1 1 ethylene carbonate/dimethylcarbonate solvent). The cell had Mylar windows, an aluminum housing, and was hermetically sealed in a glove box. 

Vacuum collectors of this type may not be suitable for sensitive substances, because the adsorbent containing the desired substance is in constant contact with a stream of air and oxidation may occur [6]. In this case, the scraped adsorbent can be placed manually in the empty tube and then extracted with solvent with the aid of vacuum. 

FIGURE 10.5 Elution profile on OH-B12 treated by microwave heating for 6 min during silica gel 60 column chromatography. Fifty milliliters of the treated OH-B12 solution (5 mmol/1) was evaporated to dryness and dissolved in a small amount of w-butanol/2-pro-panol/water (10 7 10, v/v) as a solvent. The concentrated solution was put on a column (1.4 X 15.0 cm) of silica gel 60 equilibrated with the same solvent and eluted with the same solvent in the dark. The eluate was collected at 4.0 ml with a fraction collector. Fractions I to V were pooled, evaporated to dryness, dissolved with a small amount of distilled water, and analyzed with silica gel TLC. Inset represents the mobile pattern of the OH-B12 degradation products of fractions I to V on the TLC plate. Data are typical, taken from one of five experiments. (Reprinted with permission from Watanabe, F. et al., J. Agric. Food Chem., 46, 5177-5180, 1998. Copyright (1998) American Chemical Society.)... 

In a typical generation-collection experiment, two barrels of the 0-pipette are filled with water [10,11]. If one of the barrels ( generator ) contains a cation, it can be transferred to the outer organic solvent by biasing this pipette at a sufficiently positive potential (Eg). A significant fraction of ejected cations reaches the negatively biased second pipette ( collector ) and gets transferred back into the aqueous phase [Fig. 5(a)]. When only one... 

Schematic representation of the experimental setup is shown in Fig 1.1. The electrochemical system is coupled on-line to a Quadrupole Mass Spectrometer (Balzers QMS 311 or QMG 112). Volatile substances diffusing through the PTFE membrane enter into a first chamber where a pressure between 10 1 and 10 2 mbar is maintained by means of a turbomolecular pump. In this chamber most of the gases entering in the MS (mainly solvent molecules) are eliminated, a minor part enters in a second chamber where the analyzer is placed. A second turbo molecular pump evacuates this chamber promptly and the pressure can be controlled by changing the aperture between both chambers. Depending on the type of detector used (see below) pressures in the range 10 4-10 5 mbar, (for Faraday Collector, FC), or 10 7-10 9 mbar (for Secondary Electrton Multiplier, SEM) may be established.

MCMB produced by Osaka Gas Co. has very good performance and is easily coated on the Li-Ion anode current collector (Cu). These materials are used widely throughout the world. The price is expensive, and cannot be reduced. This production process is inherently expensive due to the large volume of solvent required to be wash out and recover the beads from the pitch matrix. 

There is no question that the development and commercialization of lithium ion batteries in recent years is one of the most important successes of modem electrochemistiy. Recent commercial systems for power sources show high energy density, improved rate capabilities and extended cycle life. The major components in most of the commercial Li-ion batteries are graphite electrodes, LiCo02 cathodes and electrolyte solutions based on mixtures of alkyl carbonate solvents, and LiPF6 as the salt.1 The electrodes for these batteries always have a composite structure that includes a metallic current collector (usually copper or aluminum foil/grid for the anode and cathode, respectively), the active mass comprises micrometric size particles and a polymeric binder. 

For manufacturing of positive electrodes, pastes with the following ratio of the ingredients were applied Lithium cobaltate by Merck or by "Baltiyskaya Manufaktura" (Russia) - 42,5wt%, conductive additive (acethylene soot) - 3,5wt%, PVDF - 4wt%, solvent - the balance. Aluminium foil with the thickness of 0,02 mm was used as a current collector. 

The anodes of these two graphite samples were fabricated from a slurried mixture which contains 92 wt% of active graphite powder and 8wt% polyvinylidene difluoride (PVDF) polymer binder (Kureha 9130) and using 1 -methyl-2-pyrrolidinone (NMP) (Aldrich, >99%) as the solvent. After getting the homogenous slurry, the electrode laminates were coated on Cu current collector foil using a doctor blade in the laboratory-made laminate-coater. The laminates were then dried first at 75°C in air for 3 hrs and then the final heat treatment was carried out in a vacuum oven at 75 C for 10 hrs. Finally, the laminates were calendared to about 35% porosity in a dry room. 

In this type of study, one can correlate bands seen on HPLC and TLC. It should be noted that the reverse is easily accomplished as well. An HPLC equipped with a fraction collector can collect an impurity, evaporate off the solvent, and then evaluated on the HPTLC plate to determine if the two impurities are the same. 

The Pt current collector was first used to deposit short ( 2 pm) Pt nanoposts [37,73] into the template membrane (Fig. 21A). These Pt nanoposts anchor the alumina membrane to the Pt surface and will serve to make electrical contact to the LiMu204 nanotubes. After Pt deposition, the pores in the membrane were filled with an aqueous solution that was 0.5 M in LiNOs and 1 M in Mn(N03)2 (Fig. 21B). The excess solution was wiped from the membrane surface, and the solvent (water) was removed by heating (50°C) in vacuum for 1 hour. The assembly was then heated at 500°C in air for 5 hours. This burns away the plastic tape and also causes tubules of LiMu204 to form within the pores (Figs. 21C, 22). 

Fig. A.S Flow Chart for column Chromatography. The Central part Is the column from the sample and/or solvent is loaded at a controlled flow rate with a pump. The eluates from the column are collected in tubes of a fraction collector.

Gradient elution places special demands on solvent purity. Only carefully purified solvents should be used, and, it is recommended that prior to use they be passed over activated alumina or silica (7). The column acts as a collector of impurities which may elute as sharp peaks at a certain eluent composition and can be mistaken for sample components. It is therefore advisable to run the gradient first without injecting the sample in order to recognize the impurity peaks. 

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