Steady acetone

The acid chloride obtained as described above was dissolved in dry acetone (10 ml) and added in a steady stream to a stirred solution of 6-aminopenicillanic acid (1.08 g, 5 mmol) in a mixture of N sodium bicarbonate (15 ml) and acetone (5 ml). After the initial reaction the reaction mixture was stirred at room temperature for 45 minutes, then washed with ether (3 X 25 ml). Acidification of the aqueous solution with N hydrochloric acid (11 ml) to pH 2 and extraction with ether (3 x 15 ml) gave an ethereal extract which was decolorized with a mixture of activated charcoal and magnesium sulfate for 5 minutes. 

The values of x = 0.5 and = 1 for the kinetic orders in acetone [1] and aldehyde [2] are not trae kinetic orders for this reaction. Rather, these values represent the power-law compromise for a catalytic reaction with a more complex catalytic rate law that corresponds to the proposed steady-state catalytic cycle shown in Scheme 50.3. In the generally accepted mechanism for the intermolecular direct aldol reaction, proline reacts with the ketone substrate to form an enamine, which then attacks the aldehyde substrate." A reaction exhibiting saturation kinetics in [1] and rate-limiting addition of [2] can show apparent power law kinetics with both x and y exhibiting orders between zero and one. 

These facts suggest that variable recoveries of parathion from the evaporation procedure, as used routinely, should be expected. In general, however, the recovery data did not demonstrate a clear-cut distinction between acetone and benzene for the purpose at hand. A slow steady loss of parathion in proportion to the volume of either solvent evaporated (1) was not noted, which would indicate that the rate of evaporation is also important. The final decision as to solvent was determined by certain incidental properties of the parathion. 

The aldol condensation reaction of acetone was performed over CsOH/Si02 at a range of reaction temperatures between 373 and 673 K (a typical product distribution is shown in Figure 2). Table 1 displays the conversion of acetone along with the selectivities for the products produced once steady state conditions were achieved. Figure 3 presents the effect of temperature on the yield of the products. The activation energy for acetone conversion was calculated to be 24 kJ. mol 1. 

The MS analysis shows that the C02 profile led that of the PO profile (results not shown). The step switch results further confirm that C02 formation is faster than PO formation and that both reactions take place in parallel. GC analysis of the steady state effluent stream from the reactor revealed that propylene conversion was 10.5% at 250 °C product formation rates were determined to be 1.33, 0.12, and 34.3 pmol/min, respectively, for acetone, PO,... 

The elution curves, reported in Fig. 9.2, clearly indicate the effects of the two solvents. Acetone shows a peak of shorter retention time than toluene and this means a high extraction power for most of the active sites. However, after 6mL, the recovery reaches a steady state. Toluene gives a poor recovery when used first, and the average retention is higher. However, it turns out to be very useful in recovering the last traces. 

Dibenzotellurophene Tellurium powder (6 g, 47 mmol) and dibenzothiophene S.S -diox-ide (8 g, 37 mmol) are mixed thoroughly, the mixture is carefully heated under an atmosphere of carbon dioxide until evolution of sulphur dioxide commences, and the temperature is then regulated to achieve a steady evolution of sulphur dioxide. From time to time the sublimed dibenzothiophene dioxide is melted and allowed to flow back into the reaction mixture. After 36 h, the mixture is cooled to 20°C and extracted with boiling acetone. The extract is evaporated to dryness, the solid residue is washed several times with cold ethanol, and the washings are collected and evaporated. The residue is steam distilled and the product is recrystallized from light petroleum ether. Yield 1.0 g (10%) m.p. 93°C. 

Chemically pure reagents were used. Cadmium was added as its sulfate salt in concentrations of about 50 ppm. Lanthanides were added as nitrates. For the experiments with other metal ions so-called "black acid from a Nissan-H process was used. In this acid a large number of metal ions were present. To achieve calcium sulfate precipitation two solutions, one consisting of calcium phosphate in phosphoric acid and the other of a phosphoric acid/sulfuric acid mixture, were fed simultaneously in the 1 liter MSMPR crystallizer. The power input by the turbine stirrer was 1 kW/m. The solid content was about 10%. Each experiment was conducted for at least 8 residence times to obtain a steady state. During the experiments lic iid and solid samples were taken for analysis by ICP (Inductively Coupled Plasma spectrometry, based on atomic emission) and/or INAA (Instrumental Neutron Activation Analysis). The solid samples were washed with saturated gypsum solution (3x) and with acetone (3x), and subsequently dried at 30 C. The details of the continuous crystallization experiments are given in ref. [5]. 

Presently there are two processes that make acetone in large quantities. The feedstock for these is either isopropyl alcohol or cumene. In the last few years there has been a steady trend away from isopropyl alcohol and toward cumene, but isopropyl alcohol should continue as a precursor since manufacture of acetone from only cumene would require a balancing of the market with the co-product phenol from this process. 

CH2 is isopropyl alcohol, CH- the acetone ketyl radical, SH- the benzo-phenone ketyl radical, and AH- the camphorquinone ketyl radical. Solution of the rather complex steady state kinetics gives... 

Figure 6 shows the variation of peroxide concentration in methyl ethyl ketone slow combustion, and similar results, but with no peracid formed, have been found for acetone and diethyl ketone. The concentrations of the organic peroxy compounds run parallel to the rate of reaction, but the hydrogen peroxide concentration increases to a steady value. There thus seems little doubt that the degenerate branching intermediates at low temperatures are the alkyl hydroperoxides, and with methyl ethyl ketone, peracetic acid also. The tvfo types of cool flames given by methyl ethyl ketone may arise from the twin branching intermediates (1) observed in its combustion. 

Steady-state kinetic analysis of a competition experiment led to the conclusion that the siloxolane is formed by reaction of a vinylsilirane intermediate with acetone, and that the vinylsilirane arises from addition of the free silylene to butadiene. Since silylenes are known to react more rapidly with acetone than with butadiene, the kinetic analysis further suggested that the carbonyl sila-ylide dissociates more rapidly than it rearranges to the silyl enol ether shown in equation 64140. 

A study of oxidation of HMSA was done relative to pinacol to estimate the absolute rate of oxidation of HMSA with OH radicals in solution. Pinacol was oxidized to acetone in Fenton s oxidation. Anbar and Neta (1967) reported reaction rates of OH radicals with pinacol and acetone of 3.2 x 108 Mr1 s 1 and 4.3 x 107 Mr1 s, respectively. Table 6.1 presents the oxidation rates of pinacol (10-2 M) and pinacol-HMSA (10-2 M each). The concentrations of the reactants were Fe2+ = 104 M, H202 = 0.1 M, and pH 2. Oxidation rates for each molecule were different in separated and mixed reactions, as the steady-state concentration of free radicals depends on the chemistry of organic substrates in solution. HMSA is more reactive than pinacol by a factor of 3.9 0.8. If the absolute rate of reaction of pinacol with OH radicals was calculated to be 3.2 x 108 M 1 s, then ... 

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