PS separator

Daniel S, Diaz AJ, Martinez KM, Bench BJ, Albertorio F, Cremer PS, Separation of membrane-bound compounds by solid-supported bilayer electrophoresis. J. Am. Chem. Soc. 2007 129 8072-8073. 

PS Separation cyclic versus linear PS. Lepoittevin B, Perrot X, tJ r... 

Non-functional PS separated from co-aldehyde PS and a, co-aldehyde PS as well as from CO-Acid PS and o,co-Acid PS. 

Non-functional PS separated Baran K, Laugier S, Cramail H from 00-aldehyde PS and a, [68]... 

Analysis of multicydic and grafted PS. Linear PS separated from grafted PS and from poly(chloromethylstyrene). 

Cyclic PS separated from linear Lee HC, I.ee H, I>ee W, Chang T, PS. Retention of cyclic PS in- Roovers J [84] creased with molar mass. 

CROSS SECTION VIEW OF PEERLESS PS SEPARATION ELEMENT... 

By plotting InCp po) against x the damping coefficient a is the gradient of the resulting straight line. To separate the elements oq and Ota in a it is possible to measure the backscattering acoustic wave pressure Ps. 

In many molecular dynamics simulations, equilibration is a separate step that precedes data collection. Equilibration is generally necessary lo avoid introducing artifacts during the healing step an d to en su re th at the trajectory is aciii ally sim u laiin g eq u i librium properties. The period required for equilibration depends on the property of Interest and the molecular system. It may take about 100 ps for the system to approach equilibrium, but some properties are fairly stable after 1 0-20 ps. Suggested tim es range from. 5 ps to nearly 100 ps for medium-si/ed proteins. 

Experiment 6. Fractional Distillation of a Mixture of Benzene and Toluene. Fractionally distil about 40 ml. of a mixture of equal volumes of benzene and toluene, using the type of fractionating column shown in Fig. ii(b), in which about 18-20 cm. of the column are actually filled with glass sections, but in which the cotton-wool lagging is not used. Distil very slowlyy so that the total distillation occupies about hours. Shield the apparatus very carefully from draughts. Collect the fractions having the b.ps (a) 80-85°, ( ) 85-107°, (c) 107-111°. A sharp separation should be obtained, e.g.y these fractions should have volumes of about 19, 2, and 17 ml. respectively. 

Dinitrobenzoylation. To 0 5 g. of powdered 3,5-dinitro benzoyl chloride (preparation, p. 240) in a dry test-tube, add 2 ml. of dry methanol and warm the mixture until a clear solution is obtained. Cool and filter off the solid ester which separates. Recrystallise from petroleum (b.p. 60-80 ), and take the m.p. (M.ps., pp. 536, 537.)... 

Many semicarbazones separate when the cold reaction-mixture is set aside for a short time. (M.ps., p. 539-540.)... 

A) Phenylhydrazones and 2,4-Dinitrophenylhydrazones (see 2 abo e). The latter are often to be preferred to phenylhydrazones because (a) the phenylhydrazones may separate as syrups, and also may decompose in hot solvents cf. p. 257), ( ) the 2,4 dinitrophenylhydrazones are often formed in the cold or with only brief warming, are much less soluble, and have higher m.ps. (p. 263). 

Example. Dissolve 0 3 g. of benzoic acid in a minimum of hot water (about 70 ml.) and add 5% aqueous sodium hydro.xide until the solution is just alkaline to methyl-orange, then add i drop of dilute hydrochloric acid. Pour this solution of the sodium salt into a solution of 0 5 g, of benzylthiouronium chloride in 5 ml. of water, and cool the stirred mixture in ice-water. Filter off the benzylthiouronium salt which has separated, and recrystallise from ethanol con taining 10% of water cream-coloured cr> stals, m.p. i66 . (M.ps., pp. 543 545.)... 

Some methiodides may separate inftially as sticky syrups in this case, redissolve a portion in ethanol and add to an ethanolic solution of prcric acid, when the yellow methopicrate is usually precipitated, and when filtered off and recrystallised, has often a sharp m.p. (M.ps., pp. 553-554.)... 

Benzylthiouronium salts. Add 0 5 g. of sulphanilic acid to 10 ml. of water and 5 ml. of 10% NaOH solution, zndgently warm the shaken mixture until a clear solution is obtained. Cool, add 1 drop of phenol-phthalein solution, and then add dilute HCl dropwise with shaking until the pink colour is just discharged. Now add very dilute NaOH solution until the pink colour yt/rZ returns. Cool and add with shaking a solution of 0-5 g. of benzylthiouronium chloride in 5 ml. of water. The thiouronium salt rapidly separates filter at the pump, wash with water, drain and recrystallise from ethanol. Colourless crystals, m.p. 185°. (M.ps., p. 548.)... 

A) Benzoyl Derivative. Since acetylation and benzoylation do not always proceed smoothly with nitrophenols, it is best to reduce them to the aminophenol as in (3) above. Add an excess of 20% aqueous sodium hydroxide to the reaction mixture after reduction, cool and then add a small excess of benzoyl chloride, and shake in the usual way. The dibenzoyl derivative wiU separate. Filter, wash with water and recrystalUse. (M.ps., p. 551.)... 

The above diamines can alternatively be identified as their diacetyl derivatives. Heat under reflux 0 5 g. of the diamine with 3 ml. of acetic acid—NaOH solution will cause the separation of the diacetyl derivative. Recrystallise from ethanol. M.ps. of the diacetyl derivatives of 0-, m-, and />-phenylene diamine are 185 , 191 , and 304 respectively (p. 551). 

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