Acetone production

The selective oxidation of propene to acetone can be effected by two entirely different types of catalysts metal oxide combinations, which contain Mo03 as the essential component, and catalysts based on palladium. 

It is characteristic that the specific action of these binary oxides appears 

The characteristic reaction conditions and the special role of acidic sites in acetone formation accord very well with what is known about the mechanism. The first step in this process is the reversible uptake of a proton by the propene molecule, as evidenced by the D20 experiments carried out with a Sn02—Mo03 catalyst by Buiten [63,64], viz. 

The proton originates from acidic OH-groups of the catalyst surface. The importance of acidic sites is stressed by several authors [11,141,312] of whom Takita et al. [312] have demonstrated a linear relationship between activity and the concentration of acidic sites in the case of a Sn—Mo—O catalyst. Regarding the attachment of oxygen to the carbon formed, Moro-oka et al. proved by the use of H2180 together with 1602 that the introduced oxygen mainly stems from water. (It is noted that acrolein, formed as a by-product, did not contain ]80.) On this basis, the mechanism proposed by Buiten is 

It must be additionally assumed that the acidic OH-group is regenerated by water from the gas phase, while the remaining protons react on a different site with oxygen anions and desorb as water. A significant isotope effect for the hydrogen at the second carbon atom, observed by Buiten, may indicate that the second step in the above scheme is rate-controlling. 

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Dehydrogenation of isopropyl alcohol accounts for most of the acetone production not obtained from cumene. The vapor is passed over a brass, copper, or other catalyst at 400—500°C, and a yield of about 95% is achieved (1.09 unit weight of alcohol per unit of acetone) (13). 

Table 5. World Acetone Production Data by Regions Other Than the United States, 1987 ...

A cmde acetone product is recovered by distillation from the reaction mass. One or two additional distillation columns may be required to obtain the desired purity. If two columns are used, the first tower removes impurities such as acetaldehyde and propionaldehyde. The second tower removes undesired heavies, the major component being water. 

The economics of acetone production and its consequent market position are unusual. Traditional laws of supply and demand cannot be appHed because supply depends on the production of phenol and demand is controUed by the uses of acetone. Therefore, coproduct acetone from the cumene to phenol process will continue to dominate market supply. DeHberate production of acetone from isopropyl alcohol accommodates demand in excess of that suppHed by the phenol process. More than 75% of world and 90% of U.S. production comes from the cumene to phenol process. 

The recovery area of the plant employs fractionation to recover and purify the phenol and acetone products. Also in this section the alpha-methylstyrene is recovered and may be hydrogenated back to cumene or recovered as AMS product. The hydrogenated AMS is recycled as feedstock to the reaction area. The overall yield for the cumene process is 96 mol %. Figure 1 is a simplified process diagram. 

Propylene could be used as an alkylating agent for aromatics. An important reaction with great commercial use is the alkylation of benzene to cumene for phenol and acetone production. The reaction is discussed in Chapter 10. 

Forty-seven grams (0.5 mol) of phenol, 80 mL of 37 wt % aqueous formaldehyde (1.0 mol), and 100 mol of 4 A NaOH were charged to a flask equipped with a reflux condenser and mechanical stirrer. The reaction mixture was stirred at room temperature for 16 h, then heated on a steam bath for 1 h. The mixture was cooled and the pH adjusted to 7.0. The aqueous layer was decanted from the viscous brown liquid product, the wet organic phase was taken up in 500 mL of acetone and dried over anhydrous MgSCL, then over molecular sieves. The dried acetone product solution was filtered and evaporated to yield a water-free light brown syrup. 

Unit 4, First column. The fraction of alcohol in the overheads would be fixed by the amount allowed in the acetone product specification. Assume 1 per cent loss to the acetone is acceptable, which will give less than 1 per cent alcohol in the product fraction in the bottoms 99 per cent, 0 541 = 0.99. 

Table 4.16 Flowrate and vapor-liquid acetone production. equilibrium data for...

Uses, U.S. acetone production is used primarily in two basically different ways, 70% of it as a chemical intermediate and 20% as a solvent. As an intermediate, acetone is used to produce MIBK, methyl methacrylate (used... 

Weizmann discovered a process to produce butyl alcohol and acetone from the bacterium Clostridium acetobutylicum in 1914. With England s urgent demand for acetone, Winston Churchill (1874-1965) enlisted Weizmann to develop the Weizmann process for acetone production on an industrial scale. Large industrial plants were established in Canada, India, and the United States to provide the allies with acetone for munitions. Weizmann, who is considered the father of industrial fermentation, obtained significant status from his war contributions and used this to further his political mission of establishing a Jewish homeland. Weizmann was a leader of the Zionist movement and campaigned aggressively until the nation of Israel was established in 1948. He was the first president of Israel. 

Fermentation and distillation techniques for acetone production were replaced starting in the 1950s with the cumene oxidation process (Figure 2.1). In this process, cumene is oxidized to cumene hydroperoxide, which is then decomposed using acid to acetone and phenol. This is the primary method used to produce phenol, and acetone is produced as a co-product in the process, with a yield of about 0.6 1 of acetone to phenol. 

The kinetics of the acetone production have not been studied in detail. Fractional orders with respect to both propene and oxygen are found by Moro-oka et al. for a Co/Mo = 9/1 catalyst, which agrees with the fact that the first reaction step is certainly not rate-controlling. It is commonly reported that oxygen increases the activity, but lowers the selectivity, which is consistent with the idea of Mos+ active centres. 

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. 

Secondary hydroxyl groups also react if sufficient amount of rm-butylchlorodi-phenylsilane — imidazole — DMF reagent is used. The less hindered OH-2 of 1,4-anhydro-5,6-0-isopropylidene-D-glucitol was silylated in more than 78% yield [447]. Of the two secondary hydroxyl groups of the 4, 6 -0-isopropylidene-a-D-glucopyra-nosyl part of a kinetic acetonation product of maltose, that one at C-3 was selectively protected [448]. 

Hydrolysis proceeds with decarboxylation to give the disubstituted acetone product. 

Most important is the cumene process with an 80-85% share worldwide cumene (isopropylbenzene obtained from alkylation of benzene with propylene) is oxidized to the corresponding hydroperoxide which is decomposed to a mixture of phenol and acetone. In Japan the second most important process for acetone production is the direct oxidation of propylene with a 12% share. 

Unit 4. Some water will appear in the acetone product as for the alcohol this will be fixed by the acetone product specification. Putting q 544 = 0.99 will give less than 1 per cent water in the product. 

The conversion of the benzohydroxamic acid (191) into the amide (192) is the result of nitrogen-oxygen bond homolysis.Photodecomposition of aminophenazone (193) in aqueous solution gave N-acetyl-N-methyl-N -phenylhydrazine (194), whereas on irradiation in acetone products arising by... 

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