Hydrocarbons, atmosphere oxygenated

One consequence of the shift from grassland to shrubland is the potential for significant increases in volatile hydrocarbons added to the atmosphere. The leaves of creosotebush, Larrea tridentata, yielded 0.1 to 0.2 percent of a complex mixture of volatile compounds. That mixture contains several hundred compounds of which 100 accounted for more than 90% of the total volatiles (23). The volatiles that were identified included four monoterpene hydrocarbons, four oxygenated monoterpenes, six sesquiterpene hydrocarbons, eight aromatics like benzyl acetate and ethyl benzoate, plus... 

The extreme hazards involved in handling this highly reactive material are stressed. Freshly distilled material rapidly polymerises at ambient temperature to produce a gel and then a hard resin. These products can neither be distilled nor manipulated without explosions ranging from rapid decomposition to violent detonation. The hydrocarbon should be stored in the mixture with catalyst used to prepare it, and distilled out as required [1], The dangerously explosive gel is a peroxidic species not formed in absence of air, when some l,2-di(3-buten-l-ynyl)cyclobutane is produced by polymerisation [2], The dienyne reacts readily with atmospheric oxygen, forming an explosively unstable polymeric peroxide. Equipment used with it should be rinsed with a dilute solution of a polymerisation inhibitor to prevent formation of unstable residual films. Adequate shielding of operations is essential [3],... 

Snyder and Rapoport photolysed phylloquinone (vitamin K-l, 82) in cyclohexane solution with the surface exposed to atmospheric oxygen and moisture. This system was adopted on the assumption that the in vivo photo-oxidation would occur with the hydrocarbon side-chain dissolved in a lipid layer, but the polar naphthoquinone moiety would be in contact with water. Under the... 

Kuchta, J.M., Furno, A.L., Bartkowiak, A., and Martindill, G.H. Effect of pressure and temperature on flanunability limits of chlorinated hydrocarbons in oxygen-nitrogen and nitrogen tetroxide-nitrogen atmospheres. J. Chem. Eng. Data, 13(3) 421-428, 1968. 

Monopropellant drops have been shown to be capable of detonating in a manner similar to liquid hydrocarbon fuels (Ref 11). With monopropellant explosives, energy release per unit volume of explosive is not limited by atmospheric oxygen however, energy release per unit weight is smaller than for fuels using atmospheric oxygen... 

The oxidation of hydrocarbons by atmospheric oxygen to give hydroperoxides is called autoxidation ... 

Ethers are susceptible to attack by halogen atoms and radicals, and for this reason they are not good solvents for radical reactions. In fact, ethers are potentially hazardous chemicals, because in the presence of atmospheric oxygen radical-chain formation of peroxides occurs, and peroxides are unstable, explosion-prone compounds. This process is called autoxidation and occurs not only with ethers but with many aldehydes and hydrocarbons. The reaction may be generalized in terms of the following steps involving initiation... 

The polysulfide and elemental sulfur were unstable to autoclaving. This fact necessitated the use of a membrane to achieve sterility in those cases. The surfactant not only provided greater surface area but also minimized the amount of sulfide in contact with atmospheric oxygen since the sulfide was generally dispersed throughout the medium. The fate of the non-sulfur-containing hydrocarbons, while of real interest, is beyond the scope of this present work. 

Another type of chain reaction is sometimes observed when electrochemical oxidation of unsaturated hydrocarbons is carried out in the presence of atmospheric oxygen, which may result in the formation of dioxetanes exemplified by the oxidation of biada-mantylidene [Eq. (53)] and related compounds [121-123]. Similar behavior has been observed for other alkenes [124]. 

One effect of introducing hydrocarbons, therefore, is accelerated oxidation of nitric oxide to N02, which in turns reacts in the light to produce more ozone. Atmospheric oxygen is the source of oxidation capacity for both this reaction and the transformation of propene to more oxidized compounds. Although the ultimate fate of the hydrocarbon is oxidation to carbon dioxide,... 

Properties High tensile strength relatively low permanent set insensitive to temperature changes. Attacked by heat, atmospheric oxygen, ozone, hydrocarbons, and unsaturated fats and oils. Insoluble in acetone. Permeable to gases supports combustion abrasion resistance poor unless compounded with carbon black dissipates vibration shock high electrical resistivity. 

Each solid molecule of TATP dissociates directly into 4 gas-phase molecules. It is held together by three weak 0-0 bonds in a ring formation with three H2C and three CH2 molecules. Dissociation may be initiated by heat, pressure, or impact. The first dissociation creates enough pressure to cause surrounding TATP molecules to dissociate. The heat created by friction may initiate a reaction between atmospheric oxygen, the resultant ozone molecule, and the three hydrocarbon molecules. 

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