Cooling halogen-containing

Salts are purified by recrystallization and this procedure can be applied for ILs also. The recrystallization is performed by solving the compound in a small amount of acetonitrile and by adding a small amount of toluene to the solution. The solution was cooled in a freezer (-18°C). White crystals of the IL were formed. After filtration, the crystals were washed with an ice-cold toluene and the remaining solvent was removed by evaporation on a rotavap under reduced pressure [39]. This method is not universal as many ILs are oily liquids at room temperature or even at temperatures well below room temperature and are quite difficult to crystallize. There is of course always a loss of IL due fo the washing of the samples. It is always necessary to avoid using environmentally unfriendly solvents, especially halogen-containing ones that are not suitable for industrial applications. 

So the concerns about water intrusion with cold cleaning solvents are different and significantly less than the same with halogenated cleaning solvents. Finally, per the specifications noted in Footnote 78 and their outcomes as noted in Table 1.14, the undiluted solvent fumes emanating above the cooling coils contain no more solvent than 25% of the LEL and so can t be ignited. 

Push one end of a length of 20 cm. of stout copper wire into a cork (this wUl serve as a holder) at the other end make two or three turns about a thin glass rod. Heat the coil in the outer mantle of a Bunsen dame until it ceases to impart any colour to the dame. Allow the wire to cool somewhat and, while still warm, dip the coil into a small portion of the substance to be tested and heat again in the non-luminous dame. If the compound contains a halogen element, a green or bluish-green dame will be observed (usually after the initial smoky dame has disappeared). Before using the wire for another compound, heat it until the material from the previous test has been destroyed and the dame is not coloured. 

Ethylene oxide is produced in large, multitubular reactors cooled by pressurized boiling Hquids, eg, kerosene and water. Up to 100 metric tons of catalyst may be used in a plant. Typical feed stream contains about 30% ethylene, 7—9% oxygen, 5—7% carbon dioxide the balance is diluent plus 2—5 ppmw of a halogenated moderator. Typical reactor temperatures are in the range 230—300°C. Most producers use newer versions of the Shell cesium-promoted silver on alumina catalyst developed in the mid-1970s. 

The per pass ethylene conversion in the primary reactors is maintained at 20—30% in order to ensure catalyst selectivities of 70—80%. Vapor-phase oxidation inhibitors such as ethylene dichloride or vinyl chloride or other halogenated compounds are added to the inlet of the reactors in ppm concentrations to retard carbon dioxide formation (107,120,121). The process stream exiting the reactor may contain 1—3 mol % ethylene oxide. This hot effluent gas is then cooled ia a shell-and-tube heat exchanger to around 35—40°C by usiag the cold recycle reactor feed stream gas from the primary absorber. The cooled cmde product gas is then compressed ia a centrifugal blower before entering the primary absorber. 

In vacuum setups containing Avater, oil, or halogens, the cathode of the electronic valve is destroyed hopelessly after several hours of operation. To prevent this, ionization manometers are usually connected to a system of consecutively cooled traps. 

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