Butyraldehyde, reaction with hydrogen

Reaction of various aldehydes with hydrogen sulfide leads to substituted thiophenes, dihydrothiophenes, dithiolanes and trithiolane, as well as to six-membered ring thiopyran derivatives and dithiins. Ledl (33) obtained 2,4-dimethylthiophene (1, R Me) as a product of the reaction of propionaldehyde with hydrogen sulfide in the presence of ammonia. Sultan (29) reported the formation of 2,4-diethylthiophene (1, R - Et), 2,4-dibutyl-thiophene (1, R - Bu), and their dehydro derivatives from the reaction of ammonium sulfide with butyraldehyde and caproaldehyde (hexanal), respectively. The mechanism suggested for their formation is depicted in Scheme 1. Space limitations do not allow us to discuss the mechanism here in detail (for additional information, see ref. 29). 

A powerful oxidizer. Explosive reaction with acetaldehyde, acetic acid + heat, acetic anhydride + heat, benzaldehyde, benzene, benzylthylaniUne, butyraldehyde, 1,3-dimethylhexahydropyrimidone, diethyl ether, ethylacetate, isopropylacetate, methyl dioxane, pelargonic acid, pentyl acetate, phosphoms + heat, propionaldehyde, and other organic materials or solvents. Forms a friction- and heat-sensitive explosive mixture with potassium hexacyanoferrate. Ignites on contact with alcohols, acetic anhydride + tetrahydronaphthalene, acetone, butanol, chromium(II) sulfide, cyclohexanol, dimethyl formamide, ethanol, ethylene glycol, methanol, 2-propanol, pyridine. Violent reaction with acetic anhydride + 3-methylphenol (above 75°C), acetylene, bromine pentafluoride, glycerol, hexamethylphosphoramide, peroxyformic acid, selenium, sodium amide. Incandescent reaction with alkali metals (e.g., sodium, potassium), ammonia, arsenic, butyric acid (above 100°C), chlorine trifluoride, hydrogen sulfide + heat, sodium + heat, and sulfur. Incompatible with N,N-dimethylformamide. 

The results of 3-methyl butanal photolysis in paraffinic solution - as well as in the vapour phase , also seem to indicate that the primary processes are the same as in the photolysis of -butyraldehyde. Isovaleraldehyde has six y-hydrogen atoms accordingly, the importance of primary process III is greater here than in the photolysis of n-butyraldehyde. The nature of the secondary reactions with isovaleraldehyde (and with n-valeraldehyde ) is analogous to that for n-butyr-aldehyde. 

Hydrogen cyanide adds to hydrazones in a similar reaction.248 Moreover, it adds analogously to oximes, for Hurd and Longfellow250 found that propionaldehyde or butyraldehyde react with hydroxylamine hydrochloride, sodium cyanide, and sodium dihydrogen phosphate in aqueous solution to afford... 

Marko and coworkers found that hydrogenation of ketones (acetone, acetophenone, cyclohexanone, etc.) or aldehydes (benzaldehyde, n-butyraldehyde) were catalytically hydrogenated by Cr, Mo or W carbonyl complexes in methanol under 100bar H2 [34]. Their experiments used M(CO)6 as the catalyst precursor, with NaOCHs added under these conditions (COlsMH and [( x-H)M2(CO)ior are formed, so these reactions are similar to those discussed above. Most of their experiments were carried out at 100-160 °C, but with the Mo complex hydrogenations could be carried out at temperatures as low as 70 °C. 

DL-Isoleucine is synthesized in about 56% over-all yield by the method of Hamlin and Hartung (366). o-Oximino- -methyl-w-valeric acid (A) is prepared in 70% yield from ethyl sec.-bulyl acetoacetate, butyl nitrite and sulfuric acid. DL-Isoleucine is prepared in 80% yield by the reduction of (A) with hydrogen, palladium chloride and ethanol. This method is essentially the same as that originated by Bouveault and Locquin (117, 118, 525). By the comparable procedure of Feofilaktov (264, 265) the phenylhydrazone of methyl ethyl pyruvic acid, prepared from sec.-butyl acetoacetate and phenyldiazonium chloride (aniline and NaN02) in 68% yield, is reduced by means of rinc and alcoholic HCl to nearly the theoretical yield of a mixture of DL-isoleucine and DL-allo-isoleucine. Ehrlich (235) synthesized a mixture of isoleucine and allo-isoleucine from 2-methyl-n-butyraldehyde by the Strecker reaction. 

Manufacture of thiophene on the commercial scale involves reactions of the two component method type wherein a 4-carbon chain molecule reacts with a source of sulfur over a catalyst which also effects cyclization and aromatization. A range of suitable feedstocks has included butane, / -butanol, -butyraldehyde, crotonaldehyde, and furan the source of sulfur has included sulfur itself, hydrogen sulfide, and carbon disulfide (29—32). 

The principal commercial source of 1-butanol is -butyraldehyde [123-72-8] obtained from the Oxo reaction of propylene. A mixture of n- and isobutyraldehyde [78-84-2] is obtained in this process this mixture is either separated initially and the individual aldehyde isomers hydrogenated, or the mixture of isomeric aldehydes is hydrogenated direcdy and the n- and isobutyl alcohol product mix separated by distillation. Typically, the hydrogenation is carried out in the vapor phase over a heterogeneous catalyst. For example, passing a mixture of n- and isobutyraldehyde with 60 40 H2 N2 over a CuO—ZnO—NiO catalyst at 25—196°C and 0.7 MPa proceeds in 99.95% efficiency to the corresponding alcohols at 98.6% conversion (7,8) (see Butyraldehydes Oxo process). 

Garbonylation of Olefins. The carbonylation of olefins is a process of immense industrial importance. The process includes hydroformylation and hydrosdylation of an olefin. The hydroformylation reaction, or oxo process (qv), leads to the formation of aldehydes (qv) from olefins, carbon monoxide, hydrogen, and a transition-metal carbonyl. The hydro sdylation reaction involves addition of a sdane to an olefin (126,127). One of the most important processes in the carbonylation of olefins uses Co2(CO)g or its derivatives with phosphoms ligands as a catalyst. Propionaldehyde (128) and butyraldehyde (qv) (129) are synthesized industrially according to the following equation ... 

The n-butyraldehyde is treated with a 2 per cent w/w aqueous sodium hydroxide and undergoes an aldol condensation at a conversion efficiency of 90 per cent. The product of this reaction, 2-ethylhexanal, is separated and then reduced to 2-ethylhexanol by hydrogen in the presence of a Raney nickel catalyst with a 99 per cent conversion rate. In subsequent stages of the process (details of which are not required), 99.8 per cent of the 2-ethylhexanol is recovered at a purity of 99 per cent by weight. 

The order of activity per unit surface area was equal to that in the case of selfcondensation of acetone and in agreement with the order of basicity of the solids, namely, SrO > CaO > MgO. However, the authors found that the rate-determining step for aldol condensation of n-butyraldehyde is the a-hydrogen abstraction by the active sites, which are the surface ions. The differences in rate-determining step and active sites in the condensation of butyraldehyde and aldol condensation of the acetone were attributed to differences in acidity of the a-hydrogen in the two molecules. CaO was slightly more active than MgO at 273 K after a reaction time of 1 h, maximum conversions of 41% were observed with selectivities to 2-ethyl-3-hydroxy-hexanal and to the corresponding Tishchenko reaction product (2-ethyl-3-hydroxy- -hexyl butyrate) of 39.8 and 56.9%, respectively. 

The hydroformylation reaction, also known as the oxo reaction, is used extensively in commercial processes for the preparation of aldehydes by the reaction of one mole of an olefin with one mole each of hydrogen and carbon monoxide. The most extensive use of the reaction is in the preparation of normal- and iso-butyraldehyde from propylene. The ratio of the amount of the normal aldehyde product to the amount of the iso aldehyde product typically is referred to as the normal to iso (N I) or the normal to branched (N B) ratio. In the case of propylene, the normal- and iso-butyraldehydes obtained from propylene are in turn converted into many commercially-valuable chemical products such as n-butanol, 2-ethyl-hexanol, trimethylol propane, polyvinylbutyral, n-butyric acid, iso-butanol, neo-pentyl glycol,... 

Saponification of this diester. In 1943 Kulpinski Nord (Ref 3 4) prepd 2-ethyl-1,3-hexanediol by hydrolyzing its monoburyrate, which was previously obtd by the reaction of butyraldehyde with magnesium aluminum butox-ide. Carbide Carbon Co produced it commer-cially by the hydrogenation of butyraldol (Ref 4 p 286)... 

Five- and Six-Membered Ring Heterocycles with One, Two, or Three Sulfur Atoms. A summary of the various sulfur heterocycles formed from aldehydes in the presence of hydrogen sulfide and the corresponding analytical data are presented in Table I. Examples of aldehydes used in this reaction include propionaldehyde, butyraldehyde and caproaldehyde. 

Ethylhexanol is usually produced by subsequent aldolization of butyraldehyde produced in the oxo reaction followed by hydrogenation of the intermediate unsaturated aldehyde.89 In Esso s Aldox process, however, in situ aldol condensation is effected by suitable promoters.11 Magnesium ethoxide and soluble zinc compounds are recommended to promote controlled aldolization during the oxo reaction. The Shell variant uses potassium hydroxide. Serious disadvantages (mixed aldolization with the branched aldehyde, problems associated with recycling of the additives), however, prevented wider use of the Aldox process. 

It was discovered by Roelen in 1938 and is the oldest and largest volume catalytic reaction of alkenes, with the conversion of propylene to butyraldehyde being the mosi important. About 5 million tons of aldehydes and aldehyde derivatives (mostly alcohols) are produced annually making the process the most important industrial synthesis using a metal carbonyl complex as a catalyst. The name hydroformylation arises from the fact that in a formal sense a hydrogen atom and. formyl group are added across a double bond. The net result of the process is extension of (he carbon chain by one and introduction of oxygen into the molecule. 

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