Drying agents table

Drying agents. Table 1 shows the drying power of a number of substances commonly used in desiccators and in gas-drying trains. It gives the partial pressure of water... 

Magnesium sulphate is a useful drying agent as can be seen from the following table of equUibrium vapour pressures of the various possible tems at 25° ... 

The common drying agents that are suitable for various classes of organic compounds are listed in Table II, 39. 

M. Shepherd, "Relative Efficiencies of Drying Agents," International Critical Tables, Vol. 3, McGraw-HiU, Inc., New York, 1928. 

For convenience, many of the above drying agents are listed in Table 18 under the classes of organic compounds for which they are commonly used. 

TABLE 12.4. Common Drying Agents and their Characteristics... 

The physical constants of several other imines prepared by a similar procedure are shown in Table X. The aldimines listed in the Table can be obtained only if certain precautions are strictly observed [4b]. The method of Emerson, Hess, and Uhle [4c] could not be extended satisfactorily and the method described in Preparation 2-2 is a modification of the one described by Chancel [4d] for propylidenepropylamine. The reaction is best carried out by adding the aldehyde to the amine, without a solvent, at 0°C. When the order of addition is reversed, the yields are much lower. Potassium hydroxide is added at the end in order to remove the water formed during the reaction. The use of other drying agents such as potassium carbonate or magnesium sulfate failed to yield aldimines on distillation. The aldimines should always be distilled from fresh potassium hydroxide to yield water-white products. The aldimines are unstable and should be used within a few hours after their distillation otherwise polymeric products are obtained. 

Dry substances containing water of crystallization in desiccators over a drying agent and see that the water vapour pressure over it (Table 2) corresponds to the water vapour pressure over the crystal-lohydrate being dried. 

TABLE 11. Class DRYING AGENTS FOR CLASSES OF COMPOUNDS Dried with... 

Table II, 39. Common Drying Agents for Organic Compounds...

Table 8. Effect of nature of drying agent on polymerization of acetaldehyde by...

Table 18.1 Drying Agents for Nonaqueous Solvents Used in Electrochemistry...

Table 6.2 lists the ultraviolet cutoff for a variety of solvents commonly used in UV-VIS spectroscopy. The solvent chosen must dissolve the sample, yet be relatively transparent in the spectral region of interest. Typically, very low concentrations of sample will be present in the solvent. It is therefore important to avoid solvents that have even weak absorptions near the solute s bands of interest. Methanol and ethanol are two of the most commonly used solvents. Care must be exercised when using the latter that no benzene (an azeotropic drying agent) is present as this will alter the solvent s transparency. Normally, this will not be a problem in spectral grade solvents. 

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