From melts

Repeat the boiling point determination with the following pure liquids (a) carbon tetrachloride, A.R. (77°) (6) ethylene dibromide (132°) or chlorobenzene (132°) (c) aniline, A.R. (184-6°) and (d) nitrobenzene, A.R. (211°). An air condenser should be used for (c) and (d). Correct the observed boiling points for any appreciable deviation from the normal pressure of 760 mm. Compare the observed boiling points with the values given in parentheses and construct a calibration curve for the thermometer. Compare the latter with the curve obtained from melting point determinations (Section 111,1). 

Product from melt or suspension treatment is obtained directly as emmb or powder. Polymer recovered from solution treatment is obtained by precipitative cooling or spray drying. Polymer with now stable end groups may be washed and dried to remove impurities, especially acids or their precursors, prior to finishing operations. 

Semibatch Reactors. Semibatch reactors are the most versatile of reactor types. Thermoplastic injection molds are semibatch reactors in which shaped plastic articles are produced from melts. In mol ding thermoplastics, large clamping forces of up to 5000 metric tons are needed to keep molds together, while highly viscous polymers are forced into their cavities. Heat transfer is critical. If the molds are too cold, polymers soHdify before filling is completed if they are too hot, the time required for cooling delays production. 

Anatase and mtile are produced commercially, whereas brookite has been produced by heating amorphous titanium dioxide, which is prepared from an alkyl titanate or sodium titanate [12034-34-3] with sodium or potassium hydroxide in. an autoclave at 200—600°C for several days. Only mtile has been synthesized from melts in the form of large single crystals. More recentiy (57), a new polymorph of titanium dioxide, Ti02(B), has been demonstrated, which is formed by hydrolysis of K Ti O to form 20, followed by subsequent calcination/dehydration at 500°C. The relatively open stmcture... 

Rotating-drum-type and belt-type heat-transfer equipment forms granular products directly from fluid pastes and melts without intermediate preforms. These processes are described in Sec. 5 as examples of indirect heat transfer to and from the solid phase. When solidification results from melt freezing, the operation is known as flaking. If evaporation occurs, solidification is by diying. 

During melting, the air curtain should efficiently direct fume towards the exhaust off-take without allowing recirculation within the enclosure. The air curtain design should therefore also consider the fume trajectory when a lower updraft velocity from melting is experienced. 

Raman spectra, indicative of [M-M] + ions, are produced by the yellow glass obtained from the melt of Zn in ZnCl2 and also by the colourless, very moisture sensitive crystals of Cd2Al2Cls obtained from melts of Cd in CdCl2 and AICI3. X-ray studies show that the latter contains ethane-like [Cd2Cl6] groups with Cd-Cd reported as 257.6 pm and 256.1 pm " (cf 302 pm in the metal itself). The Cd nmr... 

Schmelz-verfahren, n. melting process, fusion process smelting process, -warme, /. heat of fusion, -wasser, n. water from melting ice or snow, -werk, n. smeltery foundry enameled work. 

Additional confirmation of the above process can be found in the fact that some iodine separation is observed from melts containing more than 0.1 mol fraction KI [359, 360]. Chernov [361] noted a similar phenomenon of iodine separation when investigating the molten system K2ZrF6 - KI. 

The scheme of the interaction mechanism (Equation 88) testifies to an electro-affinity of MeFe" ions. In addition, MeFe" ions have a lower negative charge, smaller size and higher mobility compared to MeF6X(n+1> ions. The above arguments lead to the assumption that the reduction to metal form of niobium or tantalum from melts, both by electrolysis [368] and by alkali metals, most probably occurs due to interaction with MeF6 ions. The kinetics of the reduction processes are defined by flowing equilibriums between hexa-and heptacoordinated complexes. 

Many authors studying the formation of ECC from melts and solutions suggested that preliminary unfolding and extension of macromolecules occurs. Keller and Maehin25 have shown that in all known cases (including such extreme variants as the crystallization of natural rubber under extension and a polyethylene melt under flow) the same initial process of linear nucleation occurs and fibrillar structures is formed by the macromolecu-lar chains oriented parallel to the fibrillar axes27. ... 

We carried out thermodynamic studies on the crystallization from melts of flexible-chain polymers uniaxially stretched at various degrees of molecular orientation in the melt and studied the effect of the stretching stress on thermodynamic parameters such as degree of... 

The central role of imperfections in mechanistic interpretations of decompositions of solids needs emphasizing. Apart from melting (which requires redistribution of all crystal-bonding forces, by a mechanism which has not yet been fully established) the decompositions of most solids involve the participation of atypical lattice constituents, structural distortions and/or surfaces. Such participants have, in particular instances, been identified with some certainty (e.g. excitons are important in the decompositions of some azides, dislocations are sites of nucleation in dissociations of a number of hydrates and carbonates). However, the... 

Boiling Point. Such points/ranges are distinguished from melting points and ranges by the presence of a pressure in millimeters of mercury (mmHg) after the temperature for example, 97-98/0.5. 

The crystal growth of metal borides by gas-phase methods permits preparation of products at moderate T (1000-1500°C). This is an important advantage since most borides melt at high T (ca. 3000°C), which makes their crystal growth from melts difficult. In addition, the gas-phase methods lead to the formation of single crystals and solid films of incongruently melting borides. 

Fig. 5.—The partial degradation of decamethylene adipate polyester with small percentages of decamethylene glycol (experiments 8, 13, and 17), or with lauryl alcohol (experiment 19), at 109°C, catalyzed with 0.1 equivalent percent of p-toluenesulfonic acid. The fraction of added glycol, or alcohol, unassimilated has been calculated indirectly from melt viscosity measurements and is plotted on the logarithmic ordinate scale.2 ...

Table XXXIV.—Heats of Fusion and Energy of Interaction Constants as Obtained from Melting Point Measurements on Mixtures of Cellulose Tributyrate with Diluents s...

Clinker-less binder Slag from melting of oxidized nickel ores [1474]... 

T. K. Rakhmamllin, F. A. Agzamov, V. V. Ivanov, N. Kh. Karimov, M. A. Tankibaev, and N. V. Trenkenshu. Clinker-less binder composition—contains mixture of slag from melting of oxidised nickel ores and tails from enrichment of phosphorite ores. Patent SU 1777617-A, 1992. 

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