Boiling point as a function

The material is substantially constant-boiling as a result of its having been produced by a sequence of fractionating processes involving high-efficiency distillation. Therefore, examination of the boiling point as a function of the percentage of the sample vaporized or condensed will be of little or no value in this connection. 

Molal boiling-point elevation constant a constant characteristic of a particular solvent that gives the change in boiling point as a function of solution molality used in molecular weight determinations. (17.5)... 

An alternative method of representing the behaviour of a system of this kind is to consider it under conditions of constant pressure, (fig. 13.7) we then obtain curve I, the boiling point as a function of liquid... 

Boiling Point As a Function of Alkene Branching and Molecule Size... 

Enthalpy-concentration data. An enthalpy-concentration diagram for a binary vapor-liquid mixture of A and B takes into account latent heats, heats of solution or mixing, and sensible heats of the components of the mixture. The following data are needed to construct such a diagram at a constant pressure (1) heat capacity of the liquid as a function of temperature, composition, and pressure (2) heat of solution as a function of temperature and composition (3) latent heats of vaporization as a function of composition and pressure or temperature and (4) boiling point as a function of pressure, composition, and temperature. 

DCPD decomposes rapidly at its normal boiling point to two molecules of cyclopentadiene. Purification of DCPD by distillation must be conducted imder vacuum conditions. Figure 1 depicts the lowering of the boiling point as a function of pressure. The dimer is the form in which CPD is sold commercially. 

Fig.1 Reactivities of different sulfur compounds and their boiling points as a function of diesel sulfur species [8] (catalyst C0M0/AI2O3 T = 350 °C P 100 atm)...

If the applied pressure is the atmospheric pressure, the temperature corresponds to the boiling point. In Fig. 7.5 curve I is the boiling point as a function of the mole fraction xa the boiling points of the two components A and B are Ta and Tq respectively. Curve II shows the composition of the vapor at each boiling temperature. If a mixture with composition corresponding to the... 

Fiq. 5-4. Relationship between molal, volumetric, and other average boiling points as a function of ASTM slope. Ind. Eng. Chem.)... 

If the pressure above the liquid is maintained at a fixed value (say by having the bulb containing the liquid open to the atmosphere), then the liquid may be heated up to a temperature at which the vapor pressure is equal to the external pressure. At this point vaporization will occur by the formation of bubbles in the interior of the liquid as well as at the surface this is the boiling point of the liquid at the specified external pressure. Clearly the temperature of the boiling point is a function of the external pressure in fact, about a given T, p point, the variation of the boiling point with external pressure is the inverse of the variation of the vapor pressure with temperature. 

Properties of pure compounds that exist as two phases in equilibrium are functions of one independent variable. Either temperature or pressure may be chosen as the independent variable. If one of the phases is condensed (solid or liquid) and the other phase is gas (vapor) and temperature is the independent variable, the pressure is the vapor pressure. The vapor pressure is a function only of temperature, and it is independent of the volume of the system or of the amounts of phases present. If pressure is the independent variable, the temperature is the boiling point. Therefore, the boiling point is a function only of pressure applied to the system and is independent of the total volume or of the amounts of the two phases present... 

Boiling Diagram The boiling line and dew line are plotted at constant pressure. The boiling line d(x) connects the bubble points at boiling temperature as a function of the composition of the liquid mixture. The dew line I O ) shows the eondensation temperature of the saturated vapor mixture as a function of its composition in the vapor. 

The diagram refers to the enthalpy relationships of a completely miscible binary system at a constant pressure of 1 atm. The mole fraction of component B is plotted horizontally from left to right and the enthalpy of the mixture, relative to the pure components in chosen reference states, is plotted vertically. Curve CD represents the enthalpy of the liquid phase, at its boiling-point, as a fimction of composition. Curve EF represents the enthalpy of the vapour above the boiling liquid as a function of its own composition. (Thus CE and DF are the enthalpies of vaporization of A and B respectively.) OH and IJ are typical tie-lines, i.e. a boiling liquid of composition ( is in equilibrium with vapour of composition H,... 

The simulated distillation method uses gas phase chromatography in conjunction with an apolar column, that is, a column where the elution of components is a function of their boiling points. The column temperature is increased at reproducible rate (programed temperature) and the area of the chromatogram is recorded as a function of elution time. 

The result is a distillation curve showing the temperature as a function of the per cent volume distilled (initial point, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90 and 95% distilled volume, and final boiling point). 

Distillation simulated by gas chromatography is a reproducible method for analyzing a petroleum cut it is appiicabie for mixtures whose end point is less than 500°C and the boiling range is greater than 50°C. The results of this test are presented in the form of a curve showing temperature as a function of the weight per cent distilled equivalent to an atmospheric TBP. 

Petroleum solvents are relatively light petroleum cuts, in the C4 to C14 range, and have numerous applications in industry and agriculture. Their use is often related to their tendency to evaporate consequently, they are classified as a function of their boiling points. 

Volatility is generally characterized by a distillation curve (the quantity distilled as a function of temperature). Often, only the initial and final boiling points are taken into account along with, possibly, a few intermediary points. 

On nonpolar columns, the compounds of a homologous series separate as a function of their boiling points, and linear relationships have been established between the logarithms of the retention volumes and the number of carbon atoms in the 2-, 4-, and 5-positions (see Fig. III-l). 

Table 4 2 lists the boiling points of some representative alkyl halides and alcohols When comparing the boiling points of related compounds as a function of the alkyl group we find that the boiling point increases with the number of carbon atoms as it does with alkanes... 

Fig. 2. Distribution of compounds as a function of cmde oil boiling point (a) sulfur where A, B, and C represent high (>2%), medium (ca 1.5%), and low (<0.1%) sulfur, respectively, and (b) nitrogen, where A and B represent high (ca 0.5%) andlow (<0.1%) nitrogen, respectively.

Fig. 3. Cumulative volume distilled as a function of boiling point from A, light B, intermediate and C, heavy cmde oils (not including condensates).

Fig. 4. Distribution of compound classes in cmde oils as a function of boiling point. Region A represents normal paraffins B, isoparaffins C, naphthenes ...

Tempera.ture Effect. Near the boiling point of water, the solubiUty—temperature relationship undergoes an abmpt inversion. Over a narrow temperature range, solutions become cloudy and the polymer precipitates the polymer caimot dissolve in water above this precipitation temperature. In Figure 4, this limit or cloud point is shown as a function of polymer concentration for poly(ethylene oxide) of 2 x 10 molecular weight. 

The viscosity of sulfuric acid solutions is plotted in Figure 7 (55) other viscosity data may be found in References 54—60. Surface tension of sulfuric acid solutions is presented in Figure 8 (61). Surface tension of selected concentrations of sulfuric acid as a function of temperature up to the boiling point is given in Reference 62 other data are also available (58,59,63—65). 

FIGURE 8.37 A temperature-composition diagram for benzene and toluene. The lower, blue curve shows the boiling point of the mixture as a function of composition. The upper, orange curve shows the composition of the vapor in equilibrium with the liquid at each boiling point. Thus, point B shows the vapor composition for a mixture that boils at point A. 

---