Solvent continued

TABLE 7.29 Infrared Transmission Characteristics of Selected Solvents Continued)... 

TABLE 7.48 Solvent Positions of Residual Protons in Incompletely Deuterated Solvents (Continued)... 

While this reaction with solvent continues to provide free radicals, these may be less reactive species than the original initiator fragments. We shall have more to say about the transfer of free-radical functionality to solvent in Sec. 6.8. 

Vapor-phase catalytic oxidation of dutene is a mote direct route to the dianhydtide. Hbls in Europe apparently uses this route, which eliminates the need for a separate dehydration step and for handling of any oxidants or solvents. Continuous operation is faciHtated, corrosion is minimized, and product recovery is simplified. The vapor-phase oxidation of dutene is similar to that of o-xylene to phthaHc anhydtide, and phthaHc anhydtide units can be... 

According to the ion-evaporation model, the droplets become smaller until a point is reached at which the surface charge is sufficiently high for direct ion evaporation into the gas phase to occur. In the case of the charge-residue model, repeated Coulombic explosions take place until droplets are formed that contain a single ion. Evaporation of the solvent continues until an ion is formed in the vapour phase. 

The transport of dissolved species in a solvent occurs randomly through movement of the Brownian type. The particles of the dissolved substance and of the solvent continuously collide and thus move stochastically with various velocities in various directions. The relationship between the mobility of a particle, the observation time r and the mean shift (jc2) is given by the Einstein-Smoluchowski equation (in three-dimensional case)... 

Esterification of acetic acid by isopentanol in the presence of Amberlyst-15 [38], Reaction conditions hexane solvent, continuous-flow reactor. 

The vapour of the solvent is cooled in a condenser fixed on the reaction vessel in such a way that the evaporated solvent continuously flows back again. 

As the solvent begins to soak up the chromatography plate, it first dissolves the compounds in the spot that has been placed on the base line. The compounds present will then be carried up the chromatography plate as the solvent continues to move upwards. How fast the components of a mixture are carried up the plate is determined by (1) how soluble the component is in the solvent and (2) how much the component adheres to the stationary phase. An equilibrium is established in which the components partition themselves between the stationary phase and the mobile phase in a fixed ratio. 

Hardacre et al. report the Friedel-Crafts benzoylation of anisole with benzoic anhydride to yield 4-methoxybenzophenone with various ILs and zeolite catalysts (USY, HZSM-5, H-beta, and H-mordenite). The rates of reaction were found to be significantly higher using ionic liquids compared with organic solvents.Continuous-flow studies of successful ionic liquid systems indicate that the bulk of the catalysis is due to the formation of an acid via the ion exchange of the cation with the protons of the zeolite as shown in the following reaction. Scheme 8. 

H NMR Spectral Data of Flavonoids Recorded in Various Solvents — continued... 

Extraction thimble, 153 Extraction with solvents, continuous, of liquids, 152, 153, 223t, 224 Continuous, of solids, 153, 154, 222t, 223t... 

TABLE 4.5A Boiling Points for Common Organic Solvents ([Pg.472]

In paper dirtmiatography (shown on the right) a small portion of the sample to be separated is spotted onto paper. One end of the paper is then placed into a solvent. The solvent moves up the paper via capillary action and dissolves tire sample as it passes over it. As the solvent continues to move up the paper, the more polar components of the sample move more slowly because they are attracted to the polar paper, The less polar components are not attracted to the paper and move more quickly, The result is a series of colored dots representing the different, components of the sample with the most polar near the bottom and the least polar near the top, An Tffactor can be determined for each component of the separation by dividing the distance traveled by the component by the distance traveled by the solvent. Nonpolar components have an R, factor dose to one polar components have a lower R, factor. The Rf factor is always between 0 and 1. 

Residual Peaks Observed in the 1H NMR Spectra of Common Deuterated Organic Solvents (continued)... 

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