Acetone decomposition products

Some unsaturated ketones derived from acetone can undergo base- or acid-catalyzed exothermic thermal decomposition at temperatures under 200°C. Experiments conducted under adiabatic conditions (2) indicate that mesityl oxide decomposes at 96°C in the presence of 5 wt % of aqueous sodium hydroxide (20%), and that phorone undergoes decomposition at 180°C in the presence of 1000 ppm iron. The decomposition products from these reactions are endothermic hydrolysis and cleavage back to acetone, and exothermic aldol reactions to heavy residues. 

Commercial lecithin is insoluble but infinitely dispersible in water. Treatment with water dissolves small amounts of its decomposition products and adsorbed or coacervated substances, eg, carbohydrates and salts, especially in the presence of ethanol. However, a small percentage of water dissolves or disperses in melted lecithin to form an imbibition. Lecithin forms imbibitions or absorbates with other solvents, eg, alcohols, glycols, esters, ketones, ethers, solutions of almost any organic and inorganic substance, and acetone. It is remarkable that the classic precipitant for phosphoHpids, eg, acetone, dissolves in melted lecithin readily to form a thin, uniform imbibition. Imbibition often is used to bring a reactant in intimate contact with lecithin in the preparation of lecithin derivatives. 

Allowing [VO(acen)] to react with SOCl2, [VCl2(acen)] was isolated,749 which is soluble in acetone, DMSO and CH2C12. This is less stable as a solid than [VCl2(salen)] but its decomposition product from reaction with air is not [VO(acen)]. 

However, if the photochemical reaction is run in the presence of oxygen, then of course, the methyl radicals are oxidized, and one obtains instead methanol, formaldehyde, and their decomposition products. Now, if the vessel is pumped out after a photo-oxidation and once again a normal photolysis of acetone is run, the products in the first 10 or 15 minutes are still oxidation products rather than hydrocarbon products. It takes from 15 to 30 minutes to remove whatever it is that is attached to the wall before the normal photochemical decomposition of pure acetone products are produced. These results should remind us that oxidation system do produce species, some of which are not known or understood. 

In the case of highly cross-linked material, water is not released until above 400°C, and decomposition starts above 500°C as confirmed using differential thermal analysis (DTA).55 The amount of char depends on the structure of phenol, initial cross-links, and tendency to cross-link during decomposition. The main decomposition products may include methane, acetone, CO, propanol, and propane. 

The presence of methane in the decomposition products together with the fifty per cent of carbon monoxide indicates a reaction more complicated than (1) or (4) and favors reaction (2) or (5). Rice and Herzfeld32 have proposed a series of chain reactions for the thermal decomposition of acetone which would give both methane and ethane. The recombination of CH3 and CH3CO according to (2) might account for the low quantum yield. 

Triphenyl Telluronium Fluoride1, h 3.3 g (8.6 mmol) of triphenyl telluronium chloride, 1.0 g (4.3 mmol) of silver oxide and distilled water are stirred for 2 h at 20°, the mixture is filtered, and the filtrate is neutralized with hydrofluoric acid. The resultant solution is evaporated under vacuum at 20° and the residue is recrystallized from dry acetone the product melts at 203° with decomposition beginning at 190° m.p. ISO02. 

Other workers [358] carried out the acylation of estrogens in acetone and reported the following conditions as optimal for the preparation of tris-HFB-estriol 0.1—0.3 jul of acetone per 1 jug of the substrate and 0.05 ml of HFB anhydride at room temperature for 10 min. The use of a larger amount of another solvent (benzene, methylene chloride, dimethyl sulphoxide, diethyl ether, dioxane) was said to result in the formation of a number of by-products. Poole and Morgan [359], however, stated that the HFB derivatives of some steroids are not thermally stable and that only the decomposition product is detected, e.g., cholesta-3,5-diene is produced from cholesterol. This leads to a considerably lower ECD response, so that the detection limit, which under favourable circumstances can be as low as 0.005 ng, is usually not achieved. As steroids that form unstable HFB derivatives they reported cholesterol, lumisterol, ergosterol, estradiol, pregnanetriol and others. 

Cool the reactor to —196° and remove the noncondensable materials by pumping. Allow the reactor to warm to 0° and remove the excess trifluorosilane, tetracarbonyl(trifluorosilyl)-cobalt, and any cobalt carbonyl hydride formed by pumping the volatile products through a — 78° (Dry Ice-acetone mixture) trap into a —196° trap. A dark residue will remain in the reactor consisting of unreacted dicobalt octacarbonyl and decomposition products. Unreacted trifluorosilane will be in the —196° trap. 

Divide the combined ether fractions into two equal portions, evaporate each portion to dryness Mid retain one of the residues. Treat the other ether residue witii about 200 Ll1 of an ethereal solution of diazomethane, allow to stand at room temperatme for 30 minutes, and then evaporate to dryness. Dissolve this residue and the previously retained residue, separately, in 25 jiil of ethyl acetate or hexane (do not use ethanol or acetone which can react with the decomposition products of substituted ureas). Examine the underivatised and methylated extracts by gas chromatography using tiie procedure described below. 

The bromide is prepared in the same way as the chloride, is insoluble in organic solvents, and melts at 251 C, It reacts "with alkaline sodium stannite solution, yielding a brick-red compound I., which turns brown on exposure to iightl This decomposition product when extracted with hot benzene gives II., the corresponding mercuric compound to I. It melts at 190° C., is insoluble in water, alkalies, dilute acids, or acetone, readily soluble in benzene or toluene, and is decomposed by concentrated liydrochloric acid. With mercuric chloride or picric acid it gives precipitates, but remains unchanged when boiled with potassium hydroxide, cyanide, or iodide. 

The second difference among the surfaces is the fact that, except H2O, the other three decomposition products, H2, acetone, and propene, were evolved at the same temperature on the two polar surfaces, but H2 was evolved at a lower temperature on the nonpolar surface. It is interesting to compare these results with the observations by Koga et al. who studied the decomposition of 2-propanol at 100 C on ZnO powder (13) They found that if the gas phase 2-propanol was suddenly removed from the gas phase, the evolution of hydrogen continued, but the evolution of acetone stopped. The evolution of acetone resumed after readmission of 2-propanol. This behavior can be explained by the fact that the major exposed face of their ZnO powder sample was the nonpolar plane. It is only on this surface that H2 can be evolved without concurrent evolution of acetone in the absence of gaseous propanol. 

Alternative sources of acidic species during the oxidation of isotactic polypropylene have been suggested from mass-spectrometric analysis of thermal-decomposition products from polymer hydroperoxides (Commerce et al, 1997). Acetone, acetic acid and methanol comprised 70% of the decomposition products, suggesting either a high extent of oxidation involving secondary hydroperoxides or direct reactions of hydroxyl radicals with ketones (derived through reactions discussed in the next section). 

Procedure Amines, 10-1000 jug, were acetylated by treatment with 10-20 All of redistilled acetic anhydride and 10-20 /rl of pyridine (distilled over potassium hydroxide). Excess reagents were removed in a vacuum desiccator. Methyl esters of amine acids were prepared by refluxing in methanolic hydrogen chloride. iV-Acetylation of these esters was by treatment with acetic anhydride and pyridine. Esterification of other acids was carried out with diazomethane in ether. The products were dissolved in ethyl acetate, and volumes of 0.1 to 2 ju.1 were injected into the gas chromatograph. Amounts of sample injected were about 0.1 jitg for rapidly eluted compounds and 1 p,g for those with long retention times. In some cases, acetone condensation products of the primary amines were chromatographed. Catecholamines, however, underwent decomposition under these conditions. 

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