PRODUCTION
SAFETY FORUM Explosive Decomposition O f Propylene D u r i n g compression under extrernely intense conditions propylene has b e e n found suddenly t o decompose to carbon and. a gaseous mixture calculated to c o n sist of hydrogen and methane, according to F . R. Russell and R. H . Mueller, process division, Esso Laboratories, Standard Oil Development C o . , Linden, N . J. By explosive decomposition is meant the sudden, more or less spontaneous decomposition into carbon, hydrogen, and possibly some methane, causing a sudden, violent rise in pressure and temperature. N o combustion is involved since no oxygen is present, T h e phenomenon experienced at the Esso Laboratories was a sudden and unexpected explosion of ci», grade ( 9 9 % pure) propylene w h i l e undergoing compression t o a very high pressure. T h e propylene had b e e n charged at a pressure of 9 5 5 atmospheres to a one-liter reactor maintained at 3 2 7 ° C . Reactor pressure w a s measured in the fluid in a cold section of the reactor piping. By means of a n intensifier, pressure was increased at a rate of several hundred atmospheres per minute until suddenly., at a pressure of 4S60 atmospheres, it jumped to some unknown value; the fluid on the l o w pressure side of the intensifier also rose sharply in pressure. T h e instnrment for following reactor pressure could not keep u p w i t h the rise. W h e n it did catch u p , about 15 seconds later, the pressure w a s 7S00 atmospheres and falling. About four minutes later at 6 7 0 0 atmospheres o n e of the hollow stems serving as a closure at o n e end of the reactor failed and a fog of carbon filled the room. Since t h e equipment had previously been up to pressure exceeding 10,000 atmospheres the peak pressure probably exceeded this value, according to Russell a n d Mueller. Calculations based on p u b lished compressibility factor charts indicated that considerable methane or other paraffin hydrocarbon must have b e e n formed to account for pressure much over SO00 atmospheres; hydrogen and carbon alone would not, even if none of the heat o f the reaction were absorbed b y the vessel. Explosions of ethylene in which the products were recovered and analyzed s h o w e d carbon, hydrogen, and methane as t h e principal products. Similar products for propylene might b e expected, surm i s e d the reporters. Similar explosive decompositions of ethylene h a v e b e e n reported in the literature at m u c h lower pressures ( 5 4 atmospheres at 4 6 0 ° C . to 254 atmospheres a t S31° O ) . Acetylene decomposes with e v e n less provocation. Also, cyclopentaT m s report was taken from a p a p e r presented, before the fuel, gas, and petroleum chemistry section of the 12th International Congress of P u r e and Applied Chemistry held in New York from Sept. 9 to 1 3 , 1 9 5 1 .
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diene and cyclonexadiene have been d e composed explosively. T h e ease w i t h which these unsaturated gases can b e explosively decomposed varies in the same relative order as their thermodynamic instability. The heat effect of decomposition t o t h e elements is exothermic only for acetylene and its homologs, dienes, a f e w aromatics. a n d the t w o lightest olefins, ethylene a n d propylene. Butènes and higher olefins could decompose exothermaily only b y forming methane or some other paraffin hydrocarbon. T h e ease with which acetylene, ethylene, and propylene can b e made to decompose explosively is in the same relative order as their instability as measured b y heats of formation. T h e fact that heat .of reaction is some measure of instability suggests that the rate of heat dissipation and heat release may have some effect o n conditions required for explosive decomposition. According to previously reported experiments, rate of pressure application helps to determine whether an explosion will occur; dilution with paraffin hydrocarbons or water vapor helps to prevent an explosive decomposition: and materials constituting the reactor wall have s o m e effect o n the conditions required for an explosion. These factors all suggest that the explosive decomposition m a y b e an exothermic reaction (possibly e v e n a polymerization) which rapidly accelerates and generates a hot spot capable of detonating the mixture.
Fiommabilify of Clothing Seen C o r e of H u m a n Burns Problem T h e menace of flammable clothing lies at t h e heart of t h e problem of human b u m s , Leonard Colebrook, former director of the Medical Research Council Burns Unit, Birmingham, England, asserted in an address delivered before the N e w York Academy of Medicine. It is the rapid burning of clothes which leads to extensive burning of the human body, Dr. Colebrook declared. H e said that often two or three seconds* contact with flames is sufficient t o ignite clothing, and that flames then travel rapidly over a large part of the garment. Flammable apparel is sold in every store, some materials being more dangerous than others. Wool, silk, and some kinds of nylon do not ignite, but glow and then g o out after a f e w seconds. Flannelette or viscose rayon b u m s rapidly. Dr. Colebrook proposed a three-point program to eliminate fabrics of dangerous hazards: collect data as to the kinds of fabrics which are most commonly associated with burning accidents; agree on a carefully standardized method of assessing the degree of flammability of textiles; and having decided w h i c h materials are dangerous, limit the use of these materials for clothing.
MARCH
2 4,
1952
New Text PRODUCTS Floridin products have b e e n adapted by c o n t i n u o u s research, for the m o s t a d v a n c e d t e c h n i c a l uses. O n a n y p r o b l e m o f adsorption—dehydration—catalysis—decoloration, you m a y find a n answer i n these prepared f o r m s o f Fullers Earth and B a u x i t e based A d s o r b e n t s . Y o u r i n q u i r y w i l l be g i v e n careful a t t e n t i o n .
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