Propionaldehyde, reaction with

Reactions with Alcohols. The addition of alcohols to acrolein may be catalyzed by acids or bases. By the judicious choice of reaction conditions the regioselectivity of the addition maybe controlled and alkoxy propionaldehydes, acrolein acetals, or alkoxypropionaldehyde acetals produced in high yields (66). 

Nearly quantitative generation of l,3-bis(methylthio)allyllithium was proved, as this solution yielded l,3-bis(methyIthio)propene (88-89%) and l,3-bis(methylthio)-l-butene (89%) by reaction with methanol and methyl iodide, respectively. The checkers found that lithium diisopropylamide can be replaced by w-butyllithium without any trouble for the generation of l,3-bis(methylthio)allyllithium, simplifying the procedure considerably at least in this particular case. Subsequent reaction with propionaldehyde gave l,3-bis(methylthio)-l-hexen-4-ol in 85% yield, and no appreciable amount of by-product, such as the addition product of w-hutyllithium with propionaldehyde or with the intermediate 1.3-bis(methylthio)propene, was formed. 

At high pressures the presence of the H02 radical also contributes via HCO + H02 — H202 + CO, but H02 is the least effective of OH, O, and H, as the rate constants in Appendix C will confirm. The formyl radical reacts very rapidly with the OH, O, and H radicals. However, radical concentrations are much lower than those of stable reactants and intermediates, and thus formyl reactions with these radicals are considered insignificant relative to the other formyl reactions. As will be seen when the oxidation of large hydrocarbon molecules is discussed (Section H), R is most likely a methyl radical, and the highest-order aldehydes to arise in high-temperature combustion are acetaldehyde and propionaldehyde. The acetaldehyde is the dominant form. Essentially, then, the sequence above was developed with the consideration that R was a methyl group. 

BASF led the development of a route based on ethylene and synthesis gas. Its four step process begins with the production of propionaldehyde from ethylene, CO, and H2 using a proprietary catalyst mixture that they aren t telling anything about. Reaction with formaldehyde gives methacrolein. The last two steps are the same as above—oxidation with air yields the MAA subsequent reaction with methanol yields MMA. 

Various nitro compounds have been condensed with carbonyl compounds in reactions catalyzed by alkaline earth metal oxides and hydroxides 145). It was found that the reactivities of the nitro compounds were in the order nitro-ethane > nitromethane > 2-nitropropane, and those of carbonyl compounds were propionaldehyde > isobutyraldehyde > pivalaldehyde > acetone > benzaldehyde > methyl propionate. Among the catalysts examined, MgO, CaO, Ba(OH)2, and Sr(OH)2, exhibited high activity for nitroaldol reaction of nitromethane with propionaldehyde. In reactions with these catalysts, the yields were between 60% (for MgO) and 26% (for Sr(OH)2) at 313 K after 1 h in a batch reactor. On Mg(OH)2, Ca(OH)2, and BaO, the yields were in the range of 3.8% (for BaO) and 17.5% (for Mg(OH)2). Investigation of the influence of the pre-treatment... 

The oxidation of 2-ethylhexan-l-ol to 2-ethyl-hexanal by the Oppenauer oxidation with aliphatic aldehydes such as acetaldehyde, propionaldehyde, and isobutyr-aldehyde has been investigated with gas-phase reactants and MgO as the catalyst (196). Reaction with propionaldehyde was found to be an effective synthetic route for 2-ethylhexanal preparation, whereas with acetaldehyde and isobutyraldehyde a gradual catalyst deactivation in a flow reactor was observed. 

Butenes were subjected to photosensitized reaction with molecular oxygen in methanol. 1-Butene proved unreactive. A single hydroperoxide, l-butene-3-hydroperoxide, was produced from 2-butene and isolated by preparative gas chromatography, Thermal and catalyzed decomposition of pure hydroperoxide in benzene and other solvents did not result in formation of any acetaldehyde or propionaldehyde. The absence of these aldehydes suggests that they arise by an addition mechanism in the autoxidation of butenes where they are important products. l-Butene-3-hydroperoxide in the absence of catalyst is converted predominantly to methyl vinyl ketone and a smaller quantity of methyl vinyl carbinol —volatile products usually not detected in important quantities in the autoxidation of butene. 

Acrolein is a highly reactive compound because both the double bond and aldehydic moieties partidpate in a variety of reactions, including oxidation, reduction, reactions with alcohols yielding alkoxy propionaldehydes,... 

Addition to formaldehyde [378] and other aldehydes [379,380] proceeds with high absolute stereoselectivity for the (5f )-configurated products (configurational reference changes for any substrate larger than formaldehyde ). In contrast, no or only a low level of relative acceptor diastereoselectivity at the chiral C-6 was determined in the reactions with acetaldehyde (6S/6R 1 1) [379] and propionaldehyde (130/131 = 1 2.4) [380] as the stereochemical probes. 

AW-Dimethyl-Ot-isocyanoacetamide 10 is the substrate of choice in the reaction with acetaldehyde (98.6% ee) or primary aldehydes such as propionaldehyde (96.3% ee) or isovaler-aldehyde (97.3% ee) (Scheme 8B1.5, Table 8B1.5) [19]. The oxazolinecarboxamides 11 thus prepared can be converted to P-hydroxy-a-amino acids by acidic hydrolysis. The aldol reaction... 

S)-Proline also catalyzed the Mannich-type reactions of unmodified aldehydes and N-PMP-protected imines to afford the corresponding enantiomerically enriched / -aminoaldehydes at 4 °C (Table 2.13) [71b]. The products were isolated after reduction with NaBH4, though oxidation to the / -amino acid is also possible. These reactions also provided the syn-isomer as the major diastereomer with high enantioselectivities, and proceeded well in other solvents (e.g., dioxane, THF, Et20). In the reaction of propionaldehyde and the N-PMP-imine of 4-nitrobenzaldehyde in DMF, the addition of water (up to 20%, v/v) did not affect the enantioselectivity. Similar results were obtained for the (S)-proline-catalyzed Mannich-type reactions with the glyoxylate imine where water did not reduce enantioselectivity [71b]. However, the enantioselectivity of the reaction of propionaldehyde and the N-PMP-imine of benzaldehyde in DMF was decreased by the addition of water or MeOH [71b]. 

Additions of various organic iodides to propionaldehyde /V-acylhydrazone 3a were examined in order to evaluate the scope of the reaction with respect to the radical component. In the presence of ZnCL, radical additions proved successful with secondary and tertiary iodides in moderate yields (Table 3, entries 1-4), while primary and allylic radicals were ineffective under these conditions (entries 5 and 6). Ethyl radicals generated from triethylborane can compete for the radical acceptor and, as a result, the separable ethyl radical adduct 12a (Scheme 2) was observed (<10% yield) in all cases. 

McDowell and Sharpie 2 studied the photooxidation at 23 °C. using 3130 A. radiation. They found that propionaldehyde was very similar in its behavior to acetaldehyde. The main product was perpro-pionic acid produced in a chain reaction with a quantum yield proportional to the square root of the absorbed intensity and of the order of 50 for medium intensity (10-9 einstein l.-1s ec.-1). This was in-... 

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. 

A very dangerous fire hazard when exposed to heat or flame can react with oxidizing materials. Explosive in the form of vapor when exposed to heat or flame. The monomer may undergo spontaneous, explosive polymerization. Reacts in air to form a heat-sensitive explosive product (explodes on evaporation at 60°C). May ignite on contact with benzoyl peroxide. Potentially violent reaction with the polymerization initiators azoisobutyronitrile, dibenzoyl peroxide, di-tert-butyl peroxide, propionaldehyde. To fight fire, use foam, CO2, dry chemical. When heated to decomposition it emits acrid smoke and irritating fumes. See also ESTERS. 

The reduction of a carboxyl group to an aldehyde group can be effected by a reductive desulfurization of the thiol ester with Raney nickel. The thiol esters are prepared by the reaction of the acyl chloride with an excess of ethyl mercaptan in pyridine or by reaction with lead mercaptide in dry ether. The hydrogenolysis is then carried out by refluxing an ethanol ic solution of the thiol ester with Raney nickel for 6 hours. By this new synthesis, propionaldehyde and benzaldehyde have been prepared in 73% and 62% yields, respectively. ... 

Fig. 29. Variation of the maximum rate of propionaldehyde oxidation with temperature using boric acid coated reaction vessels. (From ref. 22 by permission.)...

Taylor and Martin (1019, 1020) have described a new procedure for the direct introduction of alkenyl substituents into the pyrazine nucleus 2-chloropyrazine (63) with methylenetriphenylphosphorane (a Wittig reagent) (64, R = H) (from methyltriphenylphosphonium bromide and butyllithium) in 1,2-dimethoxyethane and subsequent treatment with benzaldehyde gave 2-styrylpyrazine (67, R = H). A similar reaction with propionaldehyde gave 2-(but-l -enyl)pyrazine (1020). 

Reaction with aldehydes.1 The reagent (1) reacts with propionaldehyde to form one diastereoisomeric form of a cyclic saturated oxyphosphorane structure with the 1,3-dioxaphospholane ring system (2). The product is hydrolyzed by water in benzene solution to give an erythro-a,/8-dihydroxy ketone (3). Compare 1,1233. 

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