Acetone decomposition

Aluminum nitrate is available commercially as aluminum nitrate nonahydrate [7784-27-2], A1(N02)3 9H20. It is a white, crystalline material with a melting point of 73.5°C that is soluble in cold water, alcohols, and acetone. Decomposition to nitric acid [7699-37-2], HNO, and basic aluminum nitrates [13473-90-0], A1(0H) (N03) where x + = 3, begins at 130°C, and dissociation to aluminum oxide and oxides of nitrogen occurs above 500°C. 

Example The quantum efficiency after the decomposition of uranyl oxalate in an experiment was found to be 0.570 at 300 nm. When light was passed through an empty cell, decomposition of 6.201 10-3 mole of the oxalate took place in 2 hours. When the cell contained acetone and irradiation continued for 10 hours, 1.4 10-3 mole of acetone were decomposed and light not absorbed by acetone decomposed 2.631 10-2 mole of the oxalate. What is the Quantum efficiency for the acetone decomposition ... 

Therefore the rate of acetone decomposition can be followed by measuring the conversion of acetone to ethane in the reaction mixture. Preliminary measurements showed that the composition of the system was essentially uniform, indicating good mixing in the reservoir (Fig. 12-1) and a recycle rate high enough that the conversion per pass through the reactor was very small. 

Experimental Procedure. As gold does not catalyse acetone decomposition, it was used to fabricate crucibles (1 cm diam., 1 cm high) for the containment of oxide specimens and as support wires for the 20/25/Nb specimens. The oxide sample weight used was 50 mg. The specimens were exposed in silica reaction vessels. 

TABLE VII - Influence of Continuous Addition of Thiophene to the Gas Phase upon Carbon Deposition from Acetone Decomposition on Fe O at 600°C... 

After 24 h subsequently in acetone alone the carbon content of the reaction product had increased to 46.7% of the original Fe304 sample weight. The extent of deposition was lower by a factor of 1.4 x 10- than that which would have been anticipated on Fe304. The low (100-125 ppm) sulphur uptake during the initial exposure to thiophene, was unlikely to have been the sole cause of this inhibition as it is not conceivable how it could have provided greater protection to acetone decomposition than the more extensive prior sulphiding (compare with Table IV). 

With Cr203 the addition of thiophene, at pressures of either 1000 iatm or 0.1 atm, did not influence either the kinetics or extent of acetone decomposition at 600°C (Fig. 1 and Table V). The sulphur uptakes for similar exposure conditions increased with thiophene partial pressure (Table V). 

Metal acetyl acetonate decomposition on alumina goes along with the formation of carbonaceous surface compounds Pt particles which were deposited in N2 are masked by adsorbed CO. Furthermore, detectable amounts of carbon are deposited on the catalyst surface when decomposing the adsorbed metal acetyl acetonate in N2 [4, 5]. The contaminations are removable by an additional air treatment of the samples as applied in catalyst preparation (see above). 

Surface properties of the support material influence the adsorption states of Pt(acac)2, Cr(acac)3 and V(acac)3 as well as the decomposition pathways of the adsorbates and finally the dispersion of the catalytic compound. The deposited particles are more mobile on silica and hence, more capable to agglomerate. Alumina-supported Pt may be stabilized by coordinativdy unsaturated Al " " surface ions similar arguments may apply for the stabilization of amorphous Cr203 on alumina. Because the metal acetyl acetonate decomposition is accompanied by deposition of carbonaceous compounds an additional air treatment of the samples is required. Finally, the fluidized-bed technique has been proven to be applicable for preparation of catalyst particles of uniform dispersion of the catalytic compound throughout the whole bed of particles. 

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