Acetone, by dehydrogenation

Production of acetone by dehydrogenation of isopropyl alcohol began in the early 1920s and remained the dominant production method through the 1960s. In the mid-1960s virtually all United States acetone was produced from propylene. A process for direct oxidation of propylene to acetone was developed by Wacker Chemie (12), but is not beheved to have been used in the United States. However, by the mid-1970s 60% of United States acetone capacity was based on cumene hydroperoxide [80-15-9], which accounted for about 65% of the acetone produced. 

Production of a-methylstyrene (AMS) from cumene by dehydrogenation was practiced commercially by Dow until 1977. It is now produced as a by-product in the production of phenol and acetone from cumene. Cumene is manufactured by alkylation of benzene with propylene. In the phenol—acetone process, cumene is oxidized in the Hquid phase thermally to cumene hydroperoxide. The hydroperoxide is spHt into phenol and acetone by a cleavage reaction catalyzed by sulfur dioxide. Up to 2% of the cumene is converted to a-methylstyrene. Phenol and acetone are large-volume chemicals and the supply of the by-product a-methylstyrene is weU in excess of its demand. Producers are forced to hydrogenate it back to cumene for recycle to the phenol—acetone plant. Estimated plant capacities of the U.S. producers of a-methylstyrene are Hsted in Table 13 (80). 

Squalane [111-01-3] (fully saturated squalene) is produced synthetically by the coupling of two molecules of geranyl acetone with diacetylene, followed by dehydration and complete hydrogenation (205). Squalane can also be made by dimerization of dehydroneroHdol, followed by dehydrogenation and hydrogenation (206). 

A variant on this structure, dioxyline, has much the same activity as the natural product but shows a better therapeutic ratio. Reduction of the oxime (113) from 3,4-dimethoxyphenyl-acetone (112) affords the veratrylamine homolog bearing a methyl group on the amine carbon atom (114). Acylation of this with 4-ethoxy-3-methoxyphenyl acetyl chloride gives the corresponding amide (115). Cyclization by means of phosphorus oxychloride followed by dehydrogenation over palladium yields dioxyline (116). ... 

Approximately 95% of the cumene is used to make phenol and acetone. A small amount is used to make a-methylstyrene by dehydrogenation. This material is used in small amounts during the polymerization of styrene to vary the properties of the resulting copolymer. 

In the minor route isopropyl alcohol, obtained from the hydrolysis of propylene, is converted into acetone by either dehydrogenation (preferred) or air oxidation. These are catalytic processes at 500°C and 40-50 psi. The acetone is purified by distillation, bp 56°C. The conversion per pass is 70-85% and the yield is over 90%. 

The resulting tertiary alcohol is then dehydrated and the ketone at 11 reduced to an alcohol by means of lithium aluminium hydride to give the intermediate (22-1). The acetal is next removed by exchange with acetone in the presence of a dilute acid. The requisite 1,4-diene functionality is then put in place by dehydrogenation... 

Most acetone is manufactured today in the United States by thermochemical cumene oxidation. It is a co-product with phenol. Acetone is also manufactured by dehydrogenation of 2-propanol, which is made by hydration of propylene. Most 1-butanol is manufactured today by hydrogenation of n-butyraldehyde, which is obtained by the hydroformylation of propylene (0x0 reaction). It is also manufactured by hydrogenation of crotonaldehyde, which is obtained by the... 

Desulfurization of petroleum feedstock (FBR), catalytic cracking (MBR or FI BR), hydrodewaxing (FBR), steam reforming of methane or naphtha (FBR), water-gas shift (CO conversion) reaction (FBR-A), ammonia synthesis (FBR-A), methanol from synthesis gas (FBR), oxidation of sulfur dioxide (FBR-A), isomerization of xylenes (FBR-A), catalytic reforming of naphtha (FBR-A), reduction of nitrobenzene to aniline (FBR), butadiene from n-butanes (FBR-A), ethylbenzene by alkylation of benzene (FBR), dehydrogenation of ethylbenzene to styrene (FBR), methyl ethyl ketone from sec-butyl alcohol (by dehydrogenation) (FBR), formaldehyde from methanol (FBR), disproportionation of toluene (FBR-A), dehydration of ethanol (FBR-A), dimethylaniline from aniline and methanol (FBR), vinyl chloride from acetone (FBR), vinyl acetate from acetylene and acetic acid (FBR), phosgene from carbon monoxide (FBR), dichloroethane by oxichlorination of ethylene (FBR), oxidation of ethylene to ethylene oxide (FBR), oxidation of benzene to maleic anhydride (FBR), oxidation of toluene to benzaldehyde (FBR), phthalic anhydride from o-xylene (FBR), furane from butadiene (FBR), acrylonitrile by ammoxidation of propylene (FI BR)... 

Table 10.6 provides figures on investments and consumption, concerning the production of acetone by the dehydrogenation of isopropanoi in the liquid and vapor phases, and also by the direct oxidation of propylene. 

Acetone is prepared by fission of cumene hydroperoxide (a,a-dimethyl-benzyl hydroperoxide) or by dehydrogenation of 2-propanol. Since acetone does not form an azeotrope with water, the water content of the industrial material is less than 0.4%. Organic impurities such as acetaldehyde and methanol amount to less than 1%. 

In the petrochemical industry the introduction of unsaturations in hydrocarbons is mainly obtained by dehydrogenation. This kind of reaction is less suitable for the functionalization of fine chemicals, because the high temperature necessary for the endothermic reaction can lead to the decomposition of thermally unstable compounds. An alternative reaction consists in the oxidative dehydrogenation, that can be carried out at lower temperatiu es. An example of this kind of reaction is constituted by the synthesis of methacrylic add (MAA, intermediate of methylmethacrylate production) via the oxidative dehydrogenation of isobutyric add (IBA), itself obtained from isobutyraldehyde (by-product of the oxo synthesis of nbutyraldehyde from propylene). This process constitutes one of the economically most interesting routes, alternative to the acetone-cyanohydrin process, which nowadays is the predominant process for the MAA production. 

Reaction of Methanol with Carbonyl Compounds. - Similar to the reaction of methanol with carboxylic acid, esters, or nitriles shown in Sections 5.2 and 6.2, attempts were made to use the HCHO which is formed by dehydrogenation of methanol. Ueda et al. performed the reaction of methanol with acetone over various transition metal catalysts supported on MgO using an acetone/methanol molar ratio of 1/10. The best performances are obtained with a catalyst containing 3.1 wt% of Fe. The main products are methyl vinyl ketone, methyl ethyl ketone, and 2-propanol. The yields are 7.1, 2.8, and 2.8 mol%, respectively, based on the charged acetone at the conversion of 20.1% selec-tivities are 34.8, 13.9, and 13.9 mol%, respectively, based on acetone. The yield of methyl vinyl ketone is much lower than that achieved in the reaction with HCHO. Unfortunately, there is no information about the reaction of methanol that exists in the feed ten times greater than acetone. It is considered that methyl ethyl ketone and 2-propanol are formed by hydrogenation of methyl vinyl ketone and acetone, respectively, with methanol. 

Myrcene is also accessible from isoprene, which derives from the steamcracker s C5-cracking fraction by dehydrogenation. In contrast, construction of its carhon skeleton, for example from acetylene and acetone or hy metathesis of isobutene and hut-2-ene, are declining in importance. [125] The sodium-catalysed dimerisation in the presence of diisopropylamine leads to myrcene. 

Some 95% of the U.S. market for acetone (2-propanone) is now supplied by the cumene-phenol process (section 12.11.2), with the remainder produced mainly by dehydrogenation of isopropanol (over a copper or zinc oxide catalyst). In Europe, co-product acetone from HP s naphtha oxidation supplements that from cumene-phenol and isopropanol. 

Probably the most intensively studied derivative of styrene with regard to its polymerization behavior is a-methylstyrene. It is produced commercially by the dehydrogenation of isopropyl-benzene (cumene) and also as a by-product in the production of phenol and acetone by the cumene oxidation process. The polymerization characteristics of ot-methylstyrene are considerably dilferent from those of styrene. Whereas radical polymerization of the pure monomer proceeds very slowly and is therefore not a practical technique [196], both ionic and coordination-type polymerization can be used to prepare poly(a-methylstyrene) (PMS). 

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