Salts slush bath

After leaving the reactant zone, the product stream enters a 0.5 in diameter FEP tube cooled by either a salt-ice bath or acetone-carbon dioxide slush bath [16]. The gas mixture was scrubbed in a soda-Hme tower. Hydrogen fluoride was trapped by adding sodium fluoride to the reaction mixture or simply adding water. Then, the product solution was extracted with dichloromethane, washed with aqueous... 

A 1-L, 3-necked, round-bottomed flask was equipped with magnetic stirrer, pressure-equalizing addition funnel with N2 inlet, low temperature thermometer, and a Friedrich condenser with N, outlet. The outlet was attached to two traps in series. The first was cooled in a Dewar of salt/ice water (- 15 C) and the second in a Dewar of dry ice/i-PrOH (— 78 C). 2-Bromo-3,3,3-trifluoropropene (50 g, 0.286 mol) and hexane (250 mL) were added to the flask. 1.6 M BuLi in hexane (190 mL, 0.304 mol, commercial) was added to the addition funnel. The flask was cooled with a hexane slush bath by addition of liquid N2 until the temperature of the solution inside the flask was - 85 °C. Then the BuLi soln was added over a period of 25 min at such a rate that the temperature remained below - 80 C. The slightly cloudy, yellowish solution was allowed to stir for an additional 10 min. Then, the hexane slush was removed, Upon reaching - 30 C, a gelatinous precipitate formed and the temperature rapidly rose to 28 "C. The volatile product was removed from solution by heating the mixture at reflux for 30 min with a slow flow of N2 through the system. The product was obtained from the dry ice trap yield 21 g (97%). 

As already mentioned, there are two general approaches to cooling the cell, immersion in the coolant and pumping coolant through the cell jacket. The simplest approach [21,27] for immersion is to use standard slush baths or salt-ice mixtures that are available for temperatures down to -160°C [28]. Crude but effective control of temperature can be achieved by cooling the cell in liquid nitrogen followed by slow warm-up in the vapor above the boiling liquid [5]. 

Generally it is better (and safer) to cool the liquid in thermometer than it is to heat it. First, try to cool the thermometer with a (table) salt-and-ice slush bath. This method should bring the liquid into the contraction chamber or bulb. Once the liquid is in the chamber or bulb, it should rejoin, leaving the air bubble on top. If there is not a clean separation of the air bubble, it may be necessary to softly tap the end of the thermometer. This tapping should be done on a soft surface such as a rubber mat, stopper, or even a pad of paper. Alternatively, you may try swinging the thermometer in an arc (such as a nurse does before placing it in your mouth)." Once joined, the liquid in the thermometer can slowly be reheated. 

Salts, such as NaCl, can be used to prepare a slush bath, a mixture used to cool or freeze something. One example is the mixture of ice and NaCl(s) used to freeze ice cream in a home ice-cream maker. Because the slush bath is at a temperature well below 0 °C, it is easy to freeze the sugar-and-milk mixture that makes up the ice cream. NaCl is also useful for deicing roads. It is effective in melting ice at temperatures as low as —21 °C (-6 °F). This is the lowest freezing point of a NaCl(aq) solution. 

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