Boiling points solvent properties

High-boiling-point solvents such as xylene can be used as a nonreactive diluent however, this is not normally done because of the high vapor pressure of the solvent and the probability that solvent remaining after cure would degrade the physical properties and... 

Solvent volatility is also an important factor in determining the properties of fibrous structures produced by electrospinning. In the electrospinning process, solvent evaporation occurs while the jet travels from the tip of the syringe to the collector. If all of the solvent evaporates on the way, fibers can be formed and deposited on the collector. However, if some solvent remains on the pol5mier, instead of dry fibers, wet fibers or thin films can be produced. Solvent volatility might play a role on the formation of pores in the fibers. A decrease in the solvent volatility resulted in a smoother fiber surface. Low-boiling-point solvents are desirable because evaporation of the solvent is enhanced and deposition of the fibers becomes easier. A rapid evaporation rate of the solvent can cause the fibers to form as ribbons with various cross sections. 

Boiling and freezing points are two basic properties of solvents often included in specifications. Based on their boiling points, solvents can be divided to low (below 100 C), medium (100-150 C) and high boiling solvents (above 150 C). 

The analysis of solids by ion chromatography requires either the transfer of the whole sample, or at least the ions of interest, into an aqueous phase. This can be carried out in different ways, depending on the solubility of the analyzed substance and the ionic content to be determined. Dissolution of the sample or extraction of the ions to be determined is normally carried out at room temperature, but can also be accelerated by gentle warming or by heating the solvent up to the boiling point. Solvent extraction which employs, basically, the principles of traditional solvent extraction, but with a higher temperature and pressure, shows better extraction properties. 

Tetrachloroethane is a good solvent for many compounds which dissolve only slightly in the common solvents it is, however, inferior in solvent power to nitrobenzene, but, on the other hand, it does not possess oxidising properties at the boiling point. 

Separations based upon differences in the physical properties of the components. When procedures (1) or (2) are unsatisfactory for the separation of a mixture of organic compounds, purely physical methods may be employed. Thus a mixture of volatile liquids may be fractionally distilled (compare Sections 11,15 and 11,17) the degree of separation may be determined by the range of boiling points and/or the refractive indices and densities of the different fractions that are collected. A mixture of non-volatile sohds may frequently be separated by making use of the differences in solubilities in inert solvents the separation is usually controlled by m.p. determinations. Sometimes one of the components of the mixture is volatile and can be separated by sublimation (see Section 11,45). 

In general, the peilluoioepoxides have boiling points that are quite similar to those of the corresponding fluoroalkenes. They can be distinguished easily from the olefins by it spectroscopy, specifically by the lack of olefinic absorption and the presence of a characteristic band between 1440 and 1550 cm . The nmr spectra of most of the epoxides have been recorded. Litde physical property data concerning these compounds have been pubhshed (Table 1). The stmcture of HFPO by electron diffraction (13) as well as its solubility and heats of solution in some organic solvents have been measured (14,15). 

Other than fuel, the largest volume appHcation for hexane is in extraction of oil from seeds, eg, soybeans, cottonseed, safflower seed, peanuts, rapeseed, etc. Hexane has been found ideal for these appHcations because of its high solvency for oil, low boiling point, and low cost. Its narrow boiling range minimises losses, and its low benzene content minimises toxicity. These same properties also make hexane a desirable solvent and reaction medium in the manufacture of polyolefins, synthetic mbbers, and some pharmaceuticals. The solvent serves as catalyst carrier and, in some systems, assists in molecular weight regulation by precipitation of the polymer as it reaches a certain molecular size. However, most solution polymerization processes are fairly old it is likely that those processes will be replaced by more efficient nonsolvent processes in time. 

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