Drowning

Naphthalenol. 2-Naphthol or p-naphthol or 2-hydroxynaphthalene/7i3 -/5 -i7 melts at 122°C and boils at 295°C, and forms colorless crystals of characteristic, phenoHc odor which darken on exposure to air or light. 2-Naphthol [135-19-3] is manufactured by fusion of sodium 2-naphthalenesulfonate with sodium hydroxide at ca 325°C, acidification of the drowned fusion mass which is quenched ia water, isolation and water-washing of the 2-naphthalenol, and vacuum distillation and flaking of the product. A continuous process of this type has been patented (69). The high sulfate content ia the primary effluent from 2-naphthol production is greatiy reduced ia modem production plants by the recovery of sodium sulfate. 

Based on differences in melting points and Hquid-phase solubilities four modes of operation possible drown-out, isothermal evaporation, adiabatic evaporation, and cooling (choice depends on stream characteristics). 

Order of preference adiabatic evaporation > isothermal evaporation > cooling >drown-out. 

Eor drown-out, look for MSA in which the component to be crystallised has low solubihty, while other components have high solubihty (MSA should be completely miscible with feed mixture). 

Fig. 11.8. Aluminium alloy quickly necks when it is drown out.

Fig. 11.9. Polythene forms o stable neck when it is drown out drown polythene is very strong.

V H COOCH3y Amorphous. (-C,H,NO-) Partly crystalline when drown. 

Fig. 23.10. Cold-drawing of o linear polymer the molecules ore drown out and aligned giving, after o draw ratio of about 4, o material which is much stronger in the draw direction than it was before.

On the completion of nitration the batch is dropped from the reaction vessel into a centrifuge and the acid mixture spun off and recovered. The nitrated linters, which still contain appreciable quantities of acid, are then plunged into a drowning tank, where the nitric acid is diluted with a large volume of water. The resultant ester is then pumped, as a slurry, into storage vats which may hold the products of several nitrations. 

The concept of programmed operation can also be applied to other types of batch crystallization e.g. precipitation via drowning-out with miscible solvents (Jones and Teodossiev, 1988). 

Figure 9.3 Potassium sulphate crystals formed by. a) cooling, (h) drowning-out with acetone Jones etai, 1987)...

The presenee of the seeond solvent during drowning-out erystallization has a marked effeet on the erystallization kineties and eonsequent partiele... 

Berry, D.A., Dye, S.R. and Ng, K.M., 1997. Synthesis of drowning-out based crystallization separations. American Institute of Chemical Engineers Journal, 43, 91. 

The loss of the Titanic in 1912 has been the subject of many books. The loss of another luxury ship, the Ville du Havre, off the Newfoundland coast in 1873, as the result of a collision, is less well known. The lifeboats were difficult to detach, as the ship was newly painted and everything was stuck fast many could not be detached in time. The life preservers, along the sides of the deck, w ere also stuck fast. Fifty-seven people were rescued, but 226 drowned. On chemical plants, painters have been known to paint everything in sight [12j. 

Altliough ail accurate assessment could not be tnade itnmediately, tlie Ashland spill look a heavy toll on tlie wildlife of the Ohio River Valley. More tluiii 5000 waterfowl were killed when their feathers became contaminated witli oil. Birds tliat e. perience oil conlaminalion lose tlieir natural insulation and buoyancy and cither drown or freeze to death. In addition, a massive fish kill was e. pectcd in the spring when the ri cr entered a new cycle. 

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