Carbon monoxide-induced decomposition

Decomposition. Acetaldehyde decomposes at temperatures above 400°C, forming principally methane and carbon monoxide [630-08-0]. The activation energy of the pyrolysis reaction is 97.7 kj/mol (408.8 kcal/mol) (27). There have been many investigations of the photolytic and radical-induced decomposition of acetaldehyde and deuterated acetaldehyde (28—30). 

Because di-/ fZ-alkyl peroxides are less susceptible to radical-induced decompositions, they are safer and more efficient radical generators than primary or secondary dialkyl peroxides. They are the preferred dialkyl peroxides for generating free radicals for commercial appHcations. Without reactive substrates present, di-/ fZ-alkyl peroxides decompose to generate alcohols, ketones, hydrocarbons, and minor amounts of ethers, epoxides, and carbon monoxide. Photolysis of di-/ fZ-butyl peroxide generates / fZ-butoxy radicals at low temperatures (75), whereas thermolysis at high temperatures generates methyl radicals by P-scission (44). 

Thermal or photo-induced decompositions of dialkyl peroxides in the presence of suitable substrates yield various products. For example, with nitric oxides, alkyl nitrites or nitrates are formed and, with carbon monoxide, Z fZ-alkyl esters are obtained (44) ... 

No information was found on the transformation of diisopropyl methylphosphonate in the atmosphere. Based on the results of environmental fate studies of diisopropyl methylphosphonate in distilled water and natural water, photolysis (either direct or indirect) is not important in the transformation of diisopropyl methylphosphonate in aquatic systems (Spanggord et al. 1979). The ultraviolet and infrared laser-induced photodegradation of diisopropyl methylphosphonate in both the vapor or liquid phase has been demonstrated (Radziemski 1981). Light hydrocarbon gases were the principal decomposition products. Hydrogen, carbon monoxide (CO), carbon dioxide (C02), and water were also detected. 

During the vacuum fractional distillation of bulked residues (7.2 t containing 30-40% of the bis(hydroxyethyl) derivative, and up to 900 ppm of iron) at 210-225°C/445-55 mbar in a mild steel still, a runaway decomposition set in and accelerated to explosion. Laboratory work on the material charged showed that exothermic decomposition on the large scale would be expected to set in around 210-230°C, and that the induction time at 215°C of 12-19 h fell to 6-9 h in presence of mild steel. Quantitative work in sealed tubes showed a maximum rate of pressure rise of 45 bar/s, to a maximum developed pressure of 200 bar. The thermally induced decomposition produced primary amine, hydrogen chloride, ethylene, methane, carbon monoxide and carbon dioxide. 

Z-Eburnamonine (XXXVI) has been produced by other reactions of vincamine. Oxidation of vincaminic acid (XL R = H) by means of ammoniacal silver nitrate was one way, and periodic acid fission of vincaminol was another (16). A different group of workers, who had probably attempted to prepare vincaminol by lithium aluminum hydride reduction of vincamine, obtained instead Z-ebumamonine in excellent yield (18). This has been rationalized as illustrated (partial formulas) by analogy with the base-induced decomposition of formic esters to carbon monoxide and alkoxide ion ... 

Other less general methods that have been reported include the extrusion of carbon monoxide from cyclobutenediones (equation 29) and the photolytic or Ag20-induced decomposition of a, a -bisdiazodibenzyl ketone . Diphenylcyclopropenone has been... 

The ruby laser-induced decomposition of 1,4-dloxane has been reported (199) to lead to ethylene, carbon monoxide, and hydrogen... 

The continuous-wave COj laser-induced decomposition of hexafluoropropanone, sensitized with SF, gave COF 3, perfluorinated hydrocarbons, carbon monoxide, and trifluoroethanoyl fluoride [1641] ... 

Two examples in which adsorptive or catalytic properties have been affected by radiation-induced desorption or decomposition are the destruction of catalytic centers on copper and nickel (55, 60) already described (Section III,A,3,c) and the effect of radiolysis of surface water on adsorption of carbon monoxide by zinc oxide (153). 

Studies of the mercury-photosensitised decomposition of 2-azetidinone and 4,4-dimethyl-2-azetidinone have been described the major products in the latter case were carbon monoxide, 2-methylpropene and 2,2-dimethylaziridine. Examples of photo-chemically induced N-dealkylation have again been reported. 

The dehydrogenation of ethanol over copper catalysts is not complete at 300° C. when moderate times of contact are used but if the temperature is raised to 350° C. or higher, secondary reactions become more and more evident. At temperatures above 350° C., copper catalysts begin to activate the decomposition of acetaldehyde to methane and carbon monoxide, to induce polymerization of the aldehyde, to cause dehydration processes to set in, to cause hydrogenation of the ethylene, and, in general, to promote secondary decompositions and condensations which complicate the product and destroy the activity of the catalyst. Hence, for the production of aldehydes and ketones it is desirable to use moderate temperatures of about 300° C. and to obtain maximum yields from the decomposition rather than maximum decomposition of alcohol per pass over the catalyst. 

Cavallo and coworkers [56] have explored the decomposition of the second-generation ruthenium methylidene and benzylidene catalysts induced by the coordination of % acids. Carbon monoxide (CO) was used as a model it-acid ligand in these computations, although it is not normaUy added during metathesis. The DFT calculations indicated that the coordination of CO trans to the Ru-alkylidene bond was highly exothermic and promoted a cascade of reactions with very low energy barriers (Scheme 7.11) [57]. The coordination of the % acid reduced the electron density on the alkylidene and thus promoted the... 

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