Crystalline Dripping

The next day comes and the hung-over chemist wakens to see a dark red solution stirring away. In some cases where the chemist had made an enormous batch of this stuff, there may be seen a small mass of crystalline precipitate at the bottom of the flask. This is no big deal and will go away in the next step. If the chemist had made this in a flat-bottomed flask (which she really should have for convenience) then the ice tray is removed, the flask returned to the stir plate, a distillation setup attached, and the acetone is vacuum distilled from the flask. After all the acetone has come over the chemist can proceed in two different ways. One way is to just keep on distilling the solution until all of the formic acid has been removed. The chemist knows that just about all the formic has been removed when there is about 300mL of thick black liquid remaining in the reaction flask and hardly any clear formic acid is dripping over into the collection flask. If one were to swirl the reaction flask, the liquid will appear syrupy and kind of coat the sides of the flask. This is more evident when the flask cools. A quick sniff of the flask may indicate that some formic is still in there, but it should be too minimal to be of any concern. 

Into the reaction flask is added 912g crystalline guaiacol and 1500g regular 48% HBr which is then slowly heated to reflux. The tepid water condenser is there to allow the bro-momethane that is formed to leave the reaction flask but is still cold enough to keep the other reactants in the reaction flask. The noxious bro-moethane condenses in the cold water condenser and drips into the chilled methanol in the collection flask. This will keep this bromoethane trapped so that the chemist will not die... 

The drip rate should be adjusted so that the dropping funnel is not plugged by crystalline cyclopentadienylsodium. 

Highly crystalline opals can be obtained 1 sedimentation, filtration, evaporation, and drip methods as demonstrated by the SEM images shown in Fig. 2. 

Poly(chloral), which is predominately isotactic, has a 4 helical conformation in the crystalline state. It is insoluble in all solvents, and thus can only be worked under restraint (by sawing or drilling). Alternatively, molded shapes can be prepared by the monomer molding technique. Poly(chloral) is stable to fuming nitric acid. It does not melt or drip, although above 200°C it decomposes into inflammable monomers. The polymer itself has a LOI of 100. The mechanical properties of the unipolymer, or the copolymer with a little isocyanate, approximate those of PMMA or PS. 

Polyethylene ignites readily and melts and drips as it bums, leaving little or no residual char. The incorporation of flame retardants into polyethylene is made difficult by the crystallinity of the polymer, which impedes homogeneous distribution of the flame retardant and reduces its effectiveness. 

The use of infusion pimips is strongly recommended. Without such pumps it is very difficult and time-consuming for the nursing staff to watch and adjust the drip rates. We use a syringe pump to inject about 60 ml 207> Intralipid in 24 hours, while a peristaltic pump (Braun Infusomat) delivers the 250 - 500 ml per 24 hours of the crystalline solution. 

Polyethylene is one of the very few crystalline plastics that will float on water. The specific gravity ranges from 0.91 to 0.96. It burns quickly with a blue flame with a yellow tip. Polyethylene drips while it burns and gives off a paraffin odor similar to a burning candle. Polyethylene is impervious to most common solvents. However, it can be dissolved in hot toluene or hot benzene. Infrared spectroscopy is used to confirm the identity of polyethylene. 

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