Crystallizers column

A 2 x 2 KI crystal column filling a (10,10) SWNT. (a) Cutaway structural representation of composite model used in the simulation calculations, (b) End-on view of the model, showing an increased lattice spacing of 0.4 nm across the capillary in two directions (assuming a symmetrical distortion), (c) HRTEM image, (d) Simulated Image. Courtesy of Professor M. L. H. Green. 

Selective etching of groups of crystal columns in alkaline solutions... 

You are probably familiar with the ionic crystals in caves. Stalagmites and stalactites are crystal columns that form when water, containing dissolved lime, drips very slowly from the ceiling of a cave onto the floor below. How do these ionic crystals grow ... 

How can you build a crystal column on your laboratory bench ... 

If the solution drips slowly enough, a tall crystal column will form. 

Raise the burette as high as it will go. Place it on the lab bench where you intend to grow your crystal column. 

Observe the crystal for 10 min. Record your observations about the crystal column or your apparatus. Continue to make observations every 10 min. 

Slurry drawn from the crystallizing columns is filtered in rotary vacuum filters where the NaHC03 crystals are water-washed. The filtered liquor then flows to the distillation unit for recovery of ammonia. The crude bicarbonate filter cake contains 3 percent... 

Figure 4. Effect on the separation of isomers on a liquid crystal column (20 m cholesteryl cinnamate) when increasing column temperature to mesophase transition temperature and beyond (left), and then gradually cooling (right) below mesophase transition. Peaks represent, in increasing retention time, hexadecane, heptadecane, (Z)-, and (E)-9-tetradecen-l-ol acetate.

Figure 2 Dependence of the retention of isomeric trans-dodecenes on the position of double bond on a liquid crystal column ...

Harju, M. Haglund, P, Comprehensive two-dimensional gas chromatography (GC x GC) of atropisomeric PCBs, combining a narrow bore 8-cyclodextrin column and a liquid crystal column J. Microcol. Sep. 2001, 13, 300-305. 

FIGURE 23.26 Continuous fluid bed crystallizer/column dryer for polyester. 

One type of suspension processes using a scraped crystallizer to create the feed suspension is the Phillips process (see McKay 1967). The crystallizer consists of a vessel with filters in the wall of the upper section. There is a heater at the bottom to remelt the crystals. Some of the melt is taken as product, some is used as reflux. The reflux serves mainly as washing liquid for the crystals which are forced downward by a reciprocating piston, or with pulses from a pulsator pump. The Phillips crystallizer column is shown in Figure 7.14. 

Figure 7.14 Phillips crystallizer column. (Reproduced with permission of Rittner and Steiner 1985.)...

Table 8. SOC schemes for (a) [Rh(thpy)2(bpy)]+ (for [Rh(thpy)(phpy)(bpy)]+ the scheme is similar),and (b) [Rh(phpy)(thpy)(bpy)]+,substitutionaUy doped into the [Rh(phpy)2(bpy)]PF host crystal. Columns 4 and 5 show the d-orbitals generated upon operation of Hsoc on the orbitals given in the top row ...

Pre-exponential factor in temperature dependence of K Half width of zeolite crystal Column length parameter defined by Eq. 11 Fractional approach to equilibrium in an uptake experiment Partial pressure Total pressure... 

One can see from Fig, 3 that conductivity in the direction parallel to the crystal columns is nearly temperature independent being not far from the temperature dependence of conductivity found for meta-lic CT complexes. The conductivity in perpendicular direction has considerably higher activation energy because it is limited by the conductivity of the polymer matrix which separates crystal columns. These results also show that the anisotropy of conductivity of the samples obtained is temperature dependent. 

For achiral molecules that, when coupling with a chiral molecule (mostly alkaloids, such as brucine, cinchonidine, and sparteine), form a pair of diastereomers with different physical properties that can be separated by the methods of fractional crystallization, column chromatography, etc., resulting in the enantiomeric resolution. No actual mechanism is necessary for this reaction. 

FIGURE 47.14 Continuous fluid-bed crystallizer/column dryer for polyester. (Courtesy of Rosin Engineering/Rosin Americas Ltd.)... 

Continuous fractionation is carried out in countercurrent flow. For the continuous fractionation of a solution containing two dissolved substances, a split column is used (Fig. 7-30). In the upper column section, the crystallization column, the less soluble component crystallizes during the counter-current contact of the mother liquor and the crystal. In the lower section, the concentrating or enrichment column, the more soluble component is favorably extracted from... 

CC Crystallization column ES Enrichment section EC Evaporator crystallizer FI Filter UR Upper reflux LR Lower reflux... 

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