Butanone, hydrogenation

Butanol, reaction over reduced nickel oxide catalysts, 35 357-359 effect of ammonia, 35 343 effect of hydrogen, 35 345 effect of pyridine, 35 344 effect of sodium, 35 342, 351 effect of temperature, 35 339 over nickel-Kieselguhr, 35 348 over supported nickel catalysts, 35 350 Butanone, hydrogenation of, 25 103 Butene, 33 22, 104-128, 131, 135 adsorption on zinc oxide, 22 42-45 by butyl alcohol dehydration, 41 348 chemisorption, 27 285 dehydrogenation, 27 191 isomerization, 27 124, 31 122-123, 32 305-308, 311-313, 41 187, 188 isomerization of, 22 45, 46 isomers... 

The detailed features of the experimental results suggest that at low temperature the reaction is kinetically controlled, while at higher temperatures the reaction appears to be thermodynamically controlled. The equilibrium between butanone/hydrogen and butanol is temperature dependent and it would seem reasonable that as the reaction temperature increased the position of equilibrium would shift to favour butanone. Given that the specification for butanone in ethyl ethanoate is typically 50ppm, the maximum butanone content of the reactor product was fixed at 17ppm, a stiff target. 

This adds compounds with active hydrogen such as water, alcohols, and carboxyUc acids (63), to give l,4-dihydroxy-2-butanone or its derivatives. 

Methyl Isopropyl Ketone. Methyl isopropyl ketone [563-80-4] (3-methyl-2-butanone) is a colorless Hquid with a characteristic odor of lower ketones. It can be produced by hydrating isoprene over an acidic catalyst at 200—300°C (150,151) or by acid-catalyzed condensation of methyl ethyl ketone and formaldehyde to 2-methyl-l-buten-3-one, foUowed by hydrogenation to the product (152). Other patented preparations are known (155,156). Methyl isopropyl ketone is used as an intermediate in the production of pharmaceuticals and fragrances (see Perfumes), and as a solvent (157). It is domestically available from Eastman (Longview, Texas) (47). 

The most recent, and probably most elegant, process for the asymmetric synthesis of (+)-estrone appHes a tandem Claisen rearrangement and intramolecular ene-reaction (Eig. 23). StereochemicaHy pure (185) is synthesized from (2R)-l,2-0-isopropyhdene-3-butanone in an overall yield of 86% in four chemical steps. Heating a toluene solution of (185), enol ether (187), and 2,6-dimethylphenol to 180°C in a sealed tube for 60 h produces (190) in 76% yield after purification. Ozonolysis of (190) followed by base-catalyzed epimerization of the C8a-hydrogen to a C8P-hydrogen (again similar to conversion of (175) to (176)) produces (184) in 46% yield from (190). Aldehyde (184) was converted to 9,11-dehydroestrone methyl ether (177) as discussed above. The overall yield of 9,11-dehydroestrone methyl ether (177) was 17% in five steps from 6-methoxy-l-tetralone (186) and (185) (201). 

Aldol reaction of the campholenic aldehyde with 2-butanone gives the intermediate ketones from condensation at both the methyl group and methylene group of 2-butanone (Fig. 6). Hydrogenation results in only one of the two products formed as having a typical sandalwood odor (160). 

Fig. 6. Campholenic aldehyde (81) reacts with 2-butanone to produce ketones that are hydrogenated to alcohols having the odors indicated.

This type of amination by an oxaziridine is assumed to be the key step of a novel process for hydrazine manufacture, in the course of which butanone in solution with ammonia is reacted with hydrogen peroxide and acetonitrile. The smooth formation of oxaziridines from Schiff bases and hydrogen peroxide-nitrile mixtures is as well known as NH transfer from an oxaziridine like (300), suggesting the intermediacy of (300) as the N—N forming agent (72TL633). 

The initial reaction between a ketene and an enamine is apparently a 1,2 cycloaddition to form an aminocyclobutanone adduct (58) (68-76a). This reaction probably occurs by way of an ionic zwitterion intermediate (75). The thermal stability of this adduct depends upon the nature of substituents Rj, R2, R3, and R. The enolic forms of 58 can exist only if Rj and/or R4 are hydrogens. If the enamine involved in the reaction is an aldehydic enamine with no 3 hydrogens and the ketene involved is di-substituted (i.e., R, R2, R3, and R4 are not hydrogens), then the cyclo-butanone adduct is thermally stable. For example, the reaction of dimethyl-ketene (61) with N,N-dimethylaminoisobutene (10) in isopropyl acetate... 

A mixture of 26 g (0.1 mol) of 0 -(4-pyridyl)-benzhydrol, 1.5 g of platinum oxide, and 250 ml of glacial acetic acid is shaken at 50°-60°C under hydrogen at a pressure of 40-50 Ib/in. The hydrogenation is complete in 2 to 3 hours. The solution is filtered and the filtrate evap-rated under reduced pressure. The residue is dissolved in a mixture of equal parts of methanol and butanone and 0.1 mol of concentrated hydrochloric acid is added. The mixture is cooled and filtered to give about 30 g of 0 -(4-piperldyl)-benzhydrol hydrochloride, MP 283°-285°C, as a white, crystalline substance. 

The acid extracts (after washing with 50 ml ether) were made alkaline with aqueous 5 N sodium hydroxide solution, the liberated base was extracted into ether (4 x 50 ml) and the ether extracts were dried (MgS04). Treatment of the extracts with hydrogen chloride gave the hydrochloride (11 grams, 70%), which was obtained as rectangular plates, MP 164° to 166°C, after several crystallizations from butanone. 

The hydrochloride salt was precipitated as an oil from an ethereal solution of the base with ethereal hydrogen chloride. It was crystallized from butanone MP 170° to 171.5°C. 

This hydrochloride, on being dissolved in water and hydrogenated with hydrogen and a nickel catalyst, gave a good yield of hydrochloride of hydroxy-4 -phenyl-1-amino-2-ethanol melting, after crystallization from a mixture of ethyl alcohol and butanone-2, at from 177° to 179°C with decomposition. 

Guo et al. [70,71,73] recently attempted to hydrogenate NBR in emulsion form using Ru-PCy complexes. However, successful hydrogenation can only be obtained when the emulsion is dissolved in a ketone solvent (2-butanone). A variety of Ru-phosphine complexes have been studied. Crosslinking of the polymer could not be avoided during the reaction. The use of carboxylic acids or first row transition metal salts as additives minimized the gel formation. The reactions under these conditions require a very high catalyst concentration for a desirable rate of hydrogenation. 

Closely related to the concept of chirality, and particularly important in biological chemistry, is the notion of prochirality. A molecule is said to be prochiral if can be converted from achiral to chiral in a single chemical step. For instance, an unsymmetrical ketone like 2-butanone is prochiral because it can be converted to the chiral alcohol 2-butanol by addition of hydrogen, as we ll see in Section 17.4. 

Mechanisms for chain transfer depend on the particular solvent or reagent. Many solvents have abstraetable hydrogens (e.g. acetone, butanone, toluene) and may react by loss of those hydrogens (Scheme 6.11). 

Fluorenylamine, 40,5 Formaldehyde, reaction with diethyl malonate to form diethyl bis-(hydroxymethyl)malonate, 40,27 Formamide, condensation with 4,4-dimethoxy-2-butanone to give 4-methylpyrimidine, 43, 77 Formic acid, and hydrogen peroxide, with indcne, 41, 53... 

S.2 Hydrogen Source for Coenzyine Regeneration 195 NADPH 2-Butanone... 

Reaction between Two Molecules of the Same Ketone. In this case, the equilibrium lies well to the left and the reaction is feasible only if the equilibrium can be shifted. This can often be done by allowing the reaction to proceed in a Soxhiet extractor (e.g., see OS I, 199). Two molecules of the same ketone can also be condensed without a Soxhiet extractor, by treatment with basic Al203. Unsymmetrical ketones condense on the side that has more hydrogens. (An exception is butanone, which reacts at the CH2 group with acid catalysts, though with basic catalysts, it too reacts at the CH3 group.)... 

These peroxidations affect the aldehydic hydrogen atom, but also hydrocarbon positions in position a of the ketonic carbonyl as already seen (see alcohol group on p.253). Butanone is one of the key compounds that are involved in accidents of this type. The peroxidation is slow, but it seems that when other compounds that can also be moderately peroxidised are present the process is aggravated by their combination. We have already seen an example of such an interaction between 2-butanol and 2-butanone. 

The effect of the nitric acid/hydrogen peroxide mixture on acetone when it is hot gives rise to an explosive oxidation, especially when the medium is confined. This situation also applies to a large number of ketones, and in particular, cyclic ketones. Cyclic di- and triperoxides form compounds that detonate, if there is no strict and very delicate thermal control. Accidents have been reported with butanone, 3-pentanone, cyclopentanone, cyclohexanone and methylcyclo-hexanones. 

Scheme 6 Complementary regioselectivities in direct aldol couplings of 2-butanone and corresponding hydrogen-mediated reductive aldol couplings of MVK...

Transfer hydrogenation in the alcohol-ketone system on metal catalysts was investigated by Patterson et al. In particular, by studying the reaction between 2-propanol and butanone on Cu they concluded that it must be a direct surface reaction (11), the mechanism being essentially a proton transfer in the adsorbed phase (Scheme 2). 

Figure 1 Time-dependent composition data is shown for the hydrogenation of aqueous 3-buten-2-ol for both (a) ultrasound irradiated and (b) magnetically stirred systems. The symbols correspond to experimental measurements (3-buten-2-ol 3BEN20L-solid circles 3-buten-2-one 3BEN20NE-open hourglass 2-butanone 2BONE-open triangles 2-butanol 2BOL-crossed squares). The lines in the ultrasound experiment simply connect the data points, whereas for the stirred experiment the lines correspond to a modeled fit (see text).

Secondary alcohols are readily autoxidised in contact with oxygen or air, forming ketones and hydrogen peroxide [1], A partly full bottle of 2-propanol exposed to sunlight for a long period became 0.36 M in peroxide and potentially explosive [2], See 2-Propanol 2-Butanone... 

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