2-Propanol catalytic oxidation

In the chemical industry, simple aldehydes and ketones are produced in large quantities for use as solvents and as starting materials to prepare a host of other compounds. For example, more than 1.9 million tons per year of formaldehyde, H2C=0, is produced in the United States for use in building insulation materials and in the adhesive resins that bind particle hoard and plywood. Acetone, (CH.3)2C"0, is widely used as an industrial solvent approximately 1.2 million tons per year is produced in the United States. Formaldehyde is synthesized industrial ) by catalytic oxidation of methanol, and one method of acetone preparation involves oxidation of 2-propanol. 

Fig. 2. Left catalytic oxidation of C3 organic compounds over MgCr204. Conversion of propane A acetone X acrolein propene. Right catalytic oxidation of 2-propanol over MgCr204. conversion of 2-propanol selectivities to acetone A propene X COx-...

A similar mechanism was formulated for the catalytic oxidation of hydrocarbons and for the photo-sensitized oxidation of 2-propanol. (2) A pure dehydrogenation can be depicted in which the platinum cleaves the hydrogen from the substrate alcohol. 

System Preheating. - The thermal efficiency of a catalytic oxidation system may be enhanced by preheating the feed gas in air prior to catalytic combustion. Tichenor and Palazzolo [5] have determined the relative contribution of the pre-heater to the overall efficiency. A mixture of iso-propanol, methyl ethyl ketone, ethyl acetate, benzene and n-hexane was combusted at a space velocity of 50,000h" in the temperature range 300-450°C over a bi-metallic Pt-Pd catalyst supported on a ceramic monolith. The results are shown in figure 1. 

Ru(teipy)(bipy)OH2f + can be prepared by treatment of [RuCl(terpy)(bipy)] with Ag" in water, or by aquation of [Ru(03SCF3Xterpy)(bipy)]. A range of substitution products of [Ru(terpy)(bipy)OH2] has been prepared." Oxidation to [Ru" (OH)(terpy)(bipy)p and [Ru (0)(terpy)(bipy)] + has been achieved electrochemically in solution and on surface film (equation jjyg system has been used for the catalytic oxidation of 2-propanol,... 

Several examples of cyclizations through intramolecular C-N bond formation catalyzed by hypervalent iodine species have been reported. Antonchick and coworkers developed an efficient organocatalytic method for the preparation of carbazoles through catalytic oxidative C-N bond formation [48]. The best yields of products were obtained in hexafluoro-2-propanol using 2,2 -diiodo-4,4, 6,6 -tetramethylbiphenyl (42) as the catalyst and peracetic acid as the oxidant, as illustrated by a representative example shown in Scheme 4.23. 

Mazzarino I, Santos A, Baldi G. Catalytic oxidation of n-propanol in a multiphase upflow reactor surface tension effects. Chem. Eng. ScL 1994 49 5699. 

Recently, Chu and Shul [128] have applied combinatorial chemistry to the screening of 66 PtRuSn-anode arrays for investigation of methanol, ethanol, and 2-propanol oxidation. The screening was performed by employing quinine as indicator of the catalytic activity, which allowed for selection of the optimum composition of electrocatalysts for DAFCs (Direct Alcohol Fuel Cells). PtRuSn (80 20 0), PtRuSn (50 0 50), and PtRuSn (50 30 20) furnished the lowest onset potential for methanol, ethanol, and 2-propanol electro-oxidation according to the CV results, respectively. The active area/composition for ethanol electro-oxidation is represented in Figure 15.8 as adapted from Ref. [128]. 

This effect is even more evident for the larger molecule, 2-propanol, which yielded an active Pt atom ratio of 0.1, even for 400 nm X 3 p,m/Pt. These results clearly indicate an effect of molecular size for the honeycomh/Pt electrodes for the catalytic oxidation of alcohols. The electrocatalytic activities of the Pt-modified nanohoneycomh films were found to he dependent on the structural parameters of the honeycomb pores and the molecular sizes of the alcohols, indicating that the selectivity of the electrodes can be controlled by variation of the pore dimensions. 

Isopropyl Alcohol. Propylene may be easily hydrolyzed to isopropyl alcohol. Eady commercial processes involved the use of sulfuric acid in an indirect process (100). The disadvantage was the need to reconcentrate the sulfuric acid after hydrolysis. Direct catalytic hydration of propylene to 2-propanol followed commercialization of the sulfuric acid process and eliniinated the need for acid reconcentration, thus reducing corrosion problems, energy use, and air pollution by SO2 and organic sulfur compounds. Gas-phase hydration takes place over supported oxides of tungsten at 540 K and 25... 

Hydrogenation. Gas-phase catalytic hydrogenation of succinic anhydride yields y-butyrolactone [96-48-0] (GBL), tetrahydrofiiran [109-99-9] (THF), 1,4-butanediol (BDO), or a mixture of these products, depending on the experimental conditions. Catalysts mentioned in the Hterature include copper chromites with various additives (72), copper—zinc oxides with promoters (73—75), and mthenium (76). The same products are obtained by hquid-phase hydrogenation catalysts used include Pd with various modifiers on various carriers (77—80), Ru on C (81) or Ru complexes (82,83), Rh on C (79), Cu—Co—Mn oxides (84), Co—Ni—Re oxides (85), Cu—Ti oxides (86), Ca—Mo—Ni on diatomaceous earth (87), and Mo—Ba—Re oxides (88). Chemical reduction of succinic anhydride to GBL or THF can be performed with 2-propanol in the presence of Zr02 catalyst (89,90). 

The most common catalysts for the Meerwein-Ponndorf-Verley reduction and Oppenauer oxidation are Alm and Lnm isopropoxides, often in combination with 2-propanol as hydride donor and solvent. These alkoxide ligands are readily exchanged under formation of 2-propanol and the metal complexes of the substrate (Scheme 20.5). Therefore, the catalytic species is in fact a mixture of metal alkoxides. 

Another common application of IR is to characterize reaction intermediates on the catalytic surfaces, often in situ during the course of the reaction [76,78,88,89], Figure 1.12 provides an example in the form of a set of transmission IR spectra obtained as a function of temperature during the oxidation of 2-propanol on Ni/Al203 [90], A clear dehydrogenation reaction is identified in these data above 440 Kby the appearance of new acetone absorption bands around 1378,1472, and 1590 cm L... 

A mixed-valent polymolybdate on active carbon was prepared from molybdenum metal and H202, followed by the addition of active carbon to the aqueous solution [114,115], This catalyzed the epoxidation of several alkenes in 2-propanol using H202 as an oxidant, while the efficiency of H202 utilization was very low (< 25%). The epoxidation likely proceeded mainly on the surface of the catalyst because the recovered catalyst showed almost similar catalytic activity. 

Recently, the influence of the preparation method of various MgO samples on their catalytic activity in the MPV reaction of cyclohexanone with 2-propanol has been reported 202). The oxides were prepared by various synthetic procedures including calcination of commercially available magnesium hydroxide and magnesium carbonate calcination of magnesium hydroxides obtained from magnesium nitrate and magnesium sulfate sol-gel synthesis and precipitation by decomposition of urea. It was concluded that the efficiency of the catalytic hydrogen transfer process was directly related to the number of basic sites in the solid. Thus, the MgO (MgO-2 sample in Table IV) prepared by hydration and subsequent calcination of a MgO sample that had been obtained from commercially available Mg(OH)2 was the most basic and the most active for the MPV process, and the MgO samples with similar populations of basic sites exhibited similar activities (Table IV). 

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