Acetone cracking

Acetone cracks to ketene, and may then be converted to anhydride by reaction with acetic acid. This process consumes somewhat less energy and is a popular subject for chemical engineering problems (24,25). The cost of acetone works against widespread appHcation of this process, however. 

Here is our MATLAB program, specialized for acetone cracking, but easily adaptable for other chemico-physical processes. 

Figure / Acetone cracking. Conversion versus space-time diagram at 750°C (from Froment, era/. [5.6]).

Figure 2 Acetone cracking. Short-cut method for estimation of activation energy from Froment, et al. (5,6]). 

Acetone cracking. Temperature profiles for calculation of equivalent reactor volume. From Froment et al. [1961a, b]. 

Figure 14.8a shows a simplified flowsheet for the manufacture of acetic anhydride as presented by Jeffries. Acetone feed is cracked in a furnace to ketene and the byproduct methane. The methane is used as furnace fuel. A second reactor forms acetic anhydride by the reaction between ketene from the first reaction and acetic acid. 

The chemist now gives her knuckles a crack and begins. An appropriate sized flask or PP container is placed in a tray of water on the stirplate. Into the flask is dumped 800mL acetone, 25mL... 

Acetone cyanohydrin is used for methacrylate manufacture. Sulfuric acid is added in greater than an equimolar amount, and by thermal cracking the acetone cyanohydrin is converted to methacrylamide sulfate [29194-31-8]. 

Used at temperatures up to 140°C, polysulfone has good resistance to aqueous solutions of acids and alkalis it is satisfactory with aliphatic solvents but is swollen by aromatics and stress cracked by several organic solvents, including acetone, ethyl acetate, trichlorethylene and carbon tetrachloride. 

Many engineering thermoplastics (e.g., polysulfone, polycarbonate, etc.) have limited utility in applications that require exposure to chemical environments. Environmental stress cracking [13] occurs when a stressed polymer is exposed to solvents. Poly(aryl ether phenylquin-oxalines) [27] and poly(aryl ether benzoxazoles) [60] show poor resistance to environmental stress cracking in the presence of acetone, chloroform, etc. This is expected because these structures are amorphous, and there is no crystallinity or liquid crystalline type structure to give solvent resistance. Thus, these materials may have limited utility in processes or applications that require multiple solvent coatings or exposures, whereas acetylene terminated polyaryl ethers [13] exhibit excellent processability, high adhesive properties, and good resistance to hydraulic fluid. 

Figure 2 Electron microphotographs of crack surface (a) and (b) and upper surface (c) and (d) of PVAc latex film. Acetone extraction (a) and (c) before, (b) and (d) after.

Fig. 2-54 Tensile test bars of two different plastics under the same stress were sprayed with acetone. The top one cracked quickly, but the other did not fail.

The condensation of acetone can also occur over acidic sites as shown by a number of authors [1,9], Generally, when this occurs other products are formed such as isobutene and acetic acid, by the cracking of DAA. Additionally mesitylene can be formed by the internal 2,7-aldol condensation of 4,6-dimethylhepta-3,5-dien-2-one which is in turn obtained by the aldol condensation of MO with a deprotonated acetone molecule [7, 8], As these species are not observed we can concluded that any acidic sites on the silica support are playing no significant role in the condensation of acetone. 

Ketene can be generated conveniently by pyrolysis of acetone in a hot tube or over a hot wire in a ketene lamp, or by pyrolysis of diketene in a hot tube. Other methods of preparation have been summarized. It has been shown that diketene cracks quite cleanly to ketene, although some allene and carbon dioxide are formed at the same time. ... 

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