Plate sublimation

Nitrate, C5H N.HN03, hygroscopic plates, sublimes (10 mm) 75. mp 110. Freely sol in water, alcohol, ether-Absorption spectrum Harper. Maebach, J. Chem. Soc. 107, 91 (1915). 

Fig. 3.7 A setup for plate sublimation. The temperature is somewhat lower than T2, so that the sublimate precipitates onto the upper wall and can grow into a single crystal if the process is carried out sufficiently slowly. After [3].

Fig. 3.8 A large anthracene crystal, prepared by plate sublimation under an inert gas atmosphere, 60 x 60 mm in size and with a thickness of 0.4 mm. From [3]. Compare the coloured plates in the Appendix and on the cover.

A simple apparatus for sublimation in a stream of air or of inert gas is shown in Fig. II, 45, 3.. d is a two-necked flask equipped with a narrow inlet tube B with stopcock and a wide tube C 12-15 inm. in diameter. The latter is fitted to a sintered glass crucible and the usual adapter and suction flask E. A well-fitting filter paper is placed on the sintered glass filter plate to collect any sublimate carried by the gas stream. 

M ass Transfer. Mass transfer in a fluidized bed can occur in several ways. Bed-to-surface mass transfer is important in plating appHcations. Transfer from the soHd surface to the gas phase is important in drying, sublimation, and desorption processes. Mass transfer can be the limiting step in a chemical reaction system. In most instances, gas from bubbles, gas voids, or the conveying gas reacts with a soHd reactant or catalyst. In catalytic systems, the surface area of a catalyst can be enormous. Eor Group A particles, surface areas of 5 to over 1000 m /g are possible. 

Acenaphtbalene [208-96-8] M 152.2, m 92-93 . Dissolved in warm redistd MeOH, filtered through a sintered glass funnel and cooled to -78° to ppte the material as yellow plates [Dainton, Ivin and Walmsley Trans Faraday Soc 56 1784 I960], Alternatively can be sublimed in vacuo. 

N-tert-Butyl urea [1118-12-3] M 116.2, m 182°, 185°(dec). Possible impurity is A,A -di-rcr/-butyl urea which is quite insol in H2O. Recrystd from hot H2O, filter off insol material, and cool to 0° to -5° with stirring. Dry in vac at room temp over KOH or H2SO4. If dried at higher temperatures it sublimes slowly. It can be recrystd from EtOH as long white needles or from 95% aq EtOH as plates. During melting point determination the bath temp has to be raised rapidly as the urea sublimes slowly above 100° at 760mm. [Org Synth Coll Vol III 151 1955.]... 

Physical properties of Fullerene C q. It does not melt below 360°, and starts to sublime at 300° in vacuo. It is a mustard coloured solid that appears brown or black with increasing film thickness. It is soluble in common organic solvents, particularly aromatic hydrocarbons which give a beautiful magenta colour. Toluene solutions are purple in colour. Sol in (5mg/mL), but dissolves slowly. Crysts of C o are both needles and plates. 

Purified by repeated crystn from MeOH. It can also be purified by sublimation under vacuum. Purity can be checked by TLC using a mixed solvent (pet ether, diethyl ether, EtOH 10 10 1) on a silica gel plate. 

Iron ennecarbonyl (di-iron nonacarbonyl) [15321-51-4] M 363.7, m 100 (dec). Wash with EtOH and Et20 and dry in air. Sublimes at 35° at high vacuum. Dark yellow plates stable for several days when kept in small amounts. Large amounts, especially when placed in a desiccator spontaneously ignite in a period of one day. It decomposes in moist air. It is insoluble in hydrocarbon solvents but forms complexes with several organic compounds. [J Am Chem Soc 72 1107 7950 Chem Ber 60 1424 1927. ]... 

Sublime in high vacuum at 120°. Yellow crystals which can be recrystallised from CCI4 as transparent plates. [J Am Chem Soc 74 6146 1952]. 

Phenan th reneq uinone (9,10-Dioxo phenan threnedihydride-9,10). Mw 208.2 orange needles mp 209°, sublimes above 360° to give orange-red plates. Obtd from phenanthrene by chromic acid oxidn in acetic acid (Ref 1)... 

In one of the first attempts to produce a systematic procedure for the identification of compounds based upon crystal morphology, Shead proposed to use profile angles as the analytical parameter [6,7]. This method was based on the use of sublimation to obtain thin crystal plates of simple geometrical forms. 

Schellenz et al. [ 1.133] confirmed that the assumption of an infinite plate in Eq. (12) is a reasonable approximation, even for drying of products in vials. They show by the measurement of temperature profiles and by X-ray photos during drying of a 5 % mannitol solution, 23 mm filling height, that the sublimation front retreats mostly from the top parallel to the bottom. The heat transfer from glass vials deforms the flat surface only to some extent close to the wall. 

In this operation some ice sublimes from the condenser to the LN2-cooled surface. However, the surfaces of the LN2 plate can be controlled between -80 °C and -100 °C, that corresponds to a water vapor pressure of approx. 5 10-4 to 2 1 () " mbar. 

The various fractions are combined, washed with 20 ml. of cold ether, and dried. Recrystallization from methylene chloride-ether (Note 7) gives 6.0-6.6 g. (62-69%) of 2-hydroxy-3-methyl-isocarbostyril as light orange plates, m.p. 175-180°. Sublimation of this material at 100-110° (0.5 mm.) gives a white product, m.p. 182-184°, with softening at 174° (Note 7). 

EC and HEEC appbcations, 5 461t electrographic, 14 329 on food packaging, 18 45-46 ink jet, 14 327 microcontact, 15 192-193 silica in, 22 376-377 steel-plate, 14 329 sublimation thermal-transfer, 9 338 textile, 9 213-222 24 621-622 of wool, 26 397-399 Printing alloys, 14 771, 772t Printing industry, electroless deposition in, 9 701-702... 

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