Overheating ethylene

In addition to these mechanical problems there are two aspects of the compression process which relate specifically to ethylene. Eirst, there is a tendency for small amounts of low molecular weight polymer to be formed and, second, the gas may decompose into carbon, hydrogen, and methane if it becomes overheated during compression. Cavities in which the gas can collect and form polymer, which hardens with time or in which the gas can become hot, need to be avoided. 

A mixture of the sulfide, ethylene glycol and hexane in a mantle-heated flask spontaneously overheated and exploded at an internal temperature of around 180°C. It had been intended to maintain the reaction temperature at 60°C, but since alcoholysis of the sulfide is exothermic, presence of the heating mantle prevented the dissipation of heat, and the reaction accelerated continuously until explosive decomposition occurred [1], An incident in similar circumstances involving interaction of the sulfide with 4-methyl-2-pentanol also led to violent eruption of the flask contents. 

B. 2,4-Dinitrobenzenesulfenyl chloride. Dry 2,4-dinitrophenyl benzyl sulfide (232 g., 0.80 mole) and 400 ml. of dry ethylene chloride are placed in a 2-1., one-necked, round-bottomed flask equipped with a stirrer (Note 3). Sulfuryl chloride (119 g., 0.88 mole) (Note 4) is added to the resulting suspension at room temperature. A mildly exothermic reaction causes the solid to dissolve quickly, usually within 1 to 2 minutes, with a temperature rise of 10-15° (Note 5). The resulting clear yellow solution is concentrated to an oil by heating under aspirator vacuum on a steam bath (Note 6). Caution Do not heat with gas or electricity because the product, like many nitro compounds, can explode if overheated.) The residual oil is cooled to 50-60°, and 3-4 volumes of dry petroleum ether (b.p. 30-60°) are added with vigorous handswirling. The oil quickly crystallizes. The mixture is cooled to room temperature and filtered to separate 2,4-dinitrobenzene-sulfenyl chloride as a yellow crystalline solid. The sulfenyl chloride is washed well with dry petroleum ether and dried at 60-80° (Note 7) weight 150-170 g. (80-90%) m.p. 95-96° (Notes 8, 9). 

Special consideration is required for exterior columns and auxiliaries that may contain unstable compounds (e.g., peroxides, nitro compounds, hydrocarbon oxides, acetylenic compounds, etc.). Here an external fire may cause overheating and polymerization, which in turn can lead to a runaway reaction and a decomposition explosion. These reactions will be related to the fire. Five major ethylene oxide column explosions caused by this sequence of events are cited in Ref. 209a. At least one involved a fatality, and in several the column was destroyed with column fragments travelling a long distance. 

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