Centrifugal molecular still

Figure 13.30. Molecular distillation and related kinds of equipment, (a) Principle of the operation of the falling film still (Chemical Engineers Handbook, McGraw-Hill, New York, 1973). (b) Thin-layer evaporator with rigid wiper blades (Luwa Co., Switzerland), (c) The Liprotherm rotating thin film evaporator, for performance intermediate to those of film evaporators and molecular stills (Sibtec Co., Stockholm), (d) Centrifugal molecular still [Hickman, Ind. Eng. Chem. 39, 686 (1947)].

Fig. 1-41. Centrifugal molecular still. [Consolidated Electrodynamics Corp.)...

We purify litre quantities of DHDECMP by vacuum distillation using a centrifugal molecular still. The fraction distilling at 0.5 Pa and 120°C is 86% pure DHDECMP and can be used without further treatment for actinide extraction and stripping studies. Impurities present in this product appear to be innocuous. For the sake of simplicity in making volume percent DHDECMP-solvent dilutions, the stock DHDECMP (86%) was considered to be pure. 

These pilot-plant tests require large quantities of good quality solvent. We had 50L of distilled DHDECMP prepared by Bray Oil Company (1925 N. Mariana Avenue, Los Angeles, Calif., 90032) starting with Wateree Chemical Company crude DHDECMP. Bray used their CVC Pilot-15 centrifugal molecular still for the distillation. Bray has just recently produced 200L of distilled DHDECMP from a batch of crude that they manufactured. This is the first time we have been able to purchase DHDECMP that is ready for extraction use. 

Figure 7-9. Schematic section of a Hickmam style centrifugal molecular still.

To a distillation flask were added 107 g l,8-dibromo-3,7-dimethyl-9-(2,6,6-trimethyl-l-cyclohexen-l-yl)-2,6-nonadien-4-yne, 100 mL toluene, and 83 g triethyl phosphite. The resulting mixture was heated at 145°C for 4 h. Upon removal of the solvent, the residue was distilled through a centrifugal molecular still to give 80.9 g 3,7-dimethyl-9-(2,5,6-trimethyl-l-cyclohexen-l-yl)-2,6,8-nonatrien-4-yn-l-ylphosphonic acid diethyl ester, in a yield of 70%, m.p. 28°C. 

F mre 9.55 Schematic section, centrifugal molecular still of Hickman [19]. 

This indicated clearly that hydroxylapatite crystallites are associated intimately with elastin fibers. In the hope of tracing this assocnation to the molecular level the fibers were dissolved by the action of elastase. Brief treatment of elastic fibers with this enzyme yields a soluble, non-dialyzable protein (Partridge et al., 1955) and it was found that after elastase treatment followed by centrifugation to remove particulate matter the soluble protein produced still contained calcium and still displayed... 

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