Crystallizer sublimator

The green hexagonal crystals sublime above 1000°C. Iron(III) fluoride is slightly soluble ia water, freely soluble ia dilute HF, and nearly iasoluble ia alcohol, ether, and benzene. It is used as a catalyst ia organic reactions. 

Adamantyl bromide [768-90-1] M 215.1, m 117-119", 118", 119.5-120". If coloured, dissolve in CCI4, wash with H2O, treat with charcoal, dry (CaCl2), filter, evap to dryness. Dissolve in a small volume of MeOH and cool in a C02/trichloroethylene bath and collect the crystals. Sublime at 90-100°/water pump vacuum. [Chem Ber 92 1629 1959 J Am Chem Soc 83 2700 1961.]... 

Sublimation (diffusion) printing is a textile process in which color patterns in dry die crystals are transferred from a release film to the fabric under high heat and pressure. The process has been adapted to plastics. The equipment used is very similar to that used for hot stamping. Under heat and pressure, the dye crystals sublime (go directly to the vapor phase from the solid phase without melting) and the vapor penetrates the plastic product. As a result, the decoration is very durable and wear resistant. It is also cost competitive against other processes such as two-step injection molding or silk screening. 

The packing energy of an organic crystal can be easily calculated by a lattice sum over pairwise interactions. The potential parameters for these calculations are summarized in Table 15. The packing energy is usually a quite accurate estimate of the crystal sublimation energy. 

Silicon disulfide Al2S3+Si02 at 1200°C J >Si Fibrous crystals. Sublimes without melting. Attacked by water ... 

The usual procedures of fractional, azeotropic, or extractive distillation under inert gases, crystallization, sublimation, and column chromatography, must be carried out very carefully. For liquid, water-insoluble monomers (e.g., styrene, Example 3-1), it is recommended that phenols or amines which may be present as stabilizers, should first be removed by shaking with dilute alkali or acid, respectively the relatively high volatility of many of these kinds of stabilizers often makes it difficult to achieve their complete removal by distillation. Gaseous monomers (e.g., lower olefins, butadiene, ethylene oxide) can be purified and stored over molecular sieves in order to remove, for example, water or CO2. 

White monoclinic crystal sublimes at 317°C melts at 432°C at 33 atm (triple point) critical temperature 452.5°C critical pressure 53.49 atm critical volume 314 cm /mol hydrolyzes in water. 

White tetragonal crystal sublimes under vacuum at 0°C decomposes slowly at 25°C density 3.24 g/cm reacts with water vapor pressure 30 torr at 0°C slightly soluble in liquid fluorine. 

Most ot the enthalpies associated with steps in the cycle can be estimated, to a greater or less accuracy, by experimental methods. The lattice energy, however, is almost always obtained theoretically rather than from experimental measurement. It might be supposed that the "enthalpy of dissociation of a lattice coukl be measured in the same way as the enthalpy of atomization of the metal and nonmctal, that is, by heating the crystal and determining how much energy is necessary to dissociate it into ions. Unfortunately, this is experimentally very difficult When a crystal sublimes (AHj), the result is not isolated gaseous ions but ion pairs and other clusters. For this reason it is necessary to use Eq. 4.13 or some more accurate version of It. Wc can then use the Bom-Haber cycle to check the accuracy of our predictions if we can obtain accurate data on every other step in the cycle Values computed from the Bom-Haber cycle are compared with those predicted by Eq. 4.13 and its modifications in Table 4.3. 

Sublimation (or Primary Drying). For the sublimation phase of the process, the frozen material usually is subjected to a vacuum of about 4.6 millimeters of mercury. The ice-crystal sublimation process can be regarded as comprised of two basic processes (l)Heal transfer, and (2) mass transfer. In essence, heat is furnished to the ice crystals to sublime them he generated waler vapor resulting is transferred out of the sublimation interface. Thus, it is evident thal sublimation will be rare-limited by both resistances to heat and mass transfer as they occur within the material. 

Orthorhombic, highly refractive crystals sublimes at room temperature decomposes at 130°C explodes at 210°C.1... 

Lustrous crystals sublimes at 331C mp25, 437°C extremely hygroscopic.1... 

Appearance Fine white powdery crystals (sublimed) or heavy, prismatic crystals properties of the two forms are the same. 

On the other hand, if the cell suspensions are too low in concentration, the cell viability might be lowered through lack of the protective effects generated by mutual contact of the cells. Furthermore, in the process of drying, the cells will be dispersed by the stream of water vapor formed during ice crystal sublimation because they lack effective networks. As a result, many cells will be lost in the process. 

Sodium amalgam acts on (Me2ClSi)2CH2 to produce greenish-yellow crystals, sublimable in vacuo at 100°C without decomposition, comprised of eight-membered rings (I) with linear Si—Hg—Si bonds ... 

Properties White crystals. Sublimes at approximately 1250C, d 2.882. Slightly soluble in water insoluble in most organic solvents. 

Properties Yellowish or reddish crystals, sublimes easily, sweettaste. Mp 173C-174C. Slightly soluble in water, alcohol, and ether. 

Properties Black crystals. Sublimes at 29.6C, polymerizes on exposure to light. 

CAS 578-94-9. C6H4(AsCl)(NH)C6H4. Properties Canary-yellow crystals. Sublimes readily, d 1.65, mp 195C, bp 410C (decomposes). Insoluble in water soluble in benzene, xylene, carbon tetrachloride. 

Properties Crystals. Sublimes partly at 100C, mp 142C. 

Properties Gray, amorphous powder (can be prepared as crystals). Sublimes at 1900C, d 3.44, bulk d 70-75 lb/cu ft depending on mesh, Mohs hardness 9+, thermal conductivity 10.83 Btu/in/sq ft/hr/F (400-2400F). Resistant to oxidation, various corrosive media, molten aluminum, zinc, lead, and tin soluble in hydrogen fluoride. 

CAS 670-54-2. (CN)2C C(CN)2. The first member of a class of compounds called cyanocarbons. Properties Colorless crystals. Sublimes above 120C, mp 198-200C, bp 223C, high thermal stability. Bums in oxygen with a hotter flame than acetylene. 

Properties Colorless, volatile crystals. Sublimes, triple point 64.0C (1134 mm Hg), mp 64.5C (2 atm), d 5.06 (25C). Soluble in liquid bromine, chlorine, carbon tetrachloride, sym-tetrachloroethane, and fluorocarbons. Reacts vigorously with water, alcohol, ether, and most metals. Vapor behaves as nearly perfect gas. 

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