Acrolein reactions

C Primary kinetic isotope effects for the concerted reaction of butadiene with ethylene, for the stepwise reaction of butadiene with ethylene and for the concerted reaction of butadiene with acrolein, have also been calculated207. The experimental values of 1.0438 and 1.0474 found recently196 in the reaction of 2,3-dimethylbutadiene with [1-14C]- and [2-14C]-l-nitro-2-phenylethylene, respectively, similar at both reacting termini, are in accord with the calculated value of 1.046 for knc/ki4c (373.15 K) in a synchronous concerted reaction of butadiene with ethylene. The 14C KIE values predicted for the asynchronous acrolein reaction are 1.015 and 1.045 for the T and 2 isotopomer, respectively207. 

Mechanism of action Cyclophosphamide [sye kloe FOSS fa mide] is the most commonly used alkylating agent. Both cyclophosphamide and ifosfamide [eye FOSS fa mide] are first biotransformed to hydroxylated intermediates by the cytochrome P-450 system (Figure 38.13). The hydroxylated intermediates undergo breakdown to form the active compounds, phospho-ramide mustard and acrolein. Reaction of the phosphoramide mustard with DNA is considered to be the cytotoxic step. [Note The therapeutic effect of these drugs is independent of the level of activity of the cytochrome P-450 system.]... 

We already know that the important interaction in the methoxybutadiene/ acrolein reaction will be that between the HOMO of the diene and the LUMO of the dienophile (Er — Es = 8-5 eV), not the other way round (Er — Es =... 

A new process for the synthesis of glycerine is based on this direct oxidation process for acrolein. Reaction of acrolein with isopropanol gives allyl alcohol and acetone as products. Hydroxylation of allyl alcohol by reaction with hydrogen peroxide, obtained from liquid-phase oxidation of isopropanol, is made to yield glycerine as a product. ... 

Conna A, Huber GW, Sauvanaud L, O Connor P. Biomass to chemicals catalytic conversion of glycerol/ water mixtures into acrolein, reaction network. J Catal 2008 257 163-71. 

Figure IV-E-1. Arrhenius plot for the rate coefficients for the NO3 -F acrolein reaction.

When exposed to sunlight, it is converted to a white insoluble resin, disacryl. Oxidized by air to propenoic acid small amounts of hy-droquinone will inhibit this. Bromine forms a dibromide which is converted by barium hydroxide into DL-fructose. The acrid odour of burning fats is due to traces of propenal. It is used in the production of methionine and in controlled polymerization reactions to give acrolein polymers. ... 

When a mixture of aniline, nitrobenzene, glycerol and concentrated sulphuric acid is heated, a vigorous reaction occurs with the formation of quinoline. It is probable that the sulphuric acid first dehydrates the glycerol giving acrolein or acraldehyde (A), which then condenses at its double bond with the amino group of the aniline to give acrolein-aniline (B), The latter in its enol... 

Reaction of triethylsilane with a, /3-unsaturated aldehydes catalyzed by Pd on carbon gives a /raff5-l,4-adduct as the main product. Reaction of acrolein gave the adduct in 86% yield, in which the 1,4-adduct 48 was 97% and the 1,2-adduct was 3%[44]. 

Acrolein (H2C=CHCH=0) reacts with sodium azide (NaNj) in aqueous acetic acid to form a compound C3H5N3O in 71% yield Propanal (CH3CH2CH=0) when subjected to the same reaction conditions is recovered unchanged Suggest a structure for the product formed from acrolein and offer an explanation for the difference in reactivity between acrolein and propanal... 

The simplest a 3 unsaturated aldehyde acrolein is prepared by heating glycerol with an acid catalyst Suggest a mechanism for this reaction... 

The base-catalyzed reaction of acetaldehyde with excess formaldehyde [50-00-0] is the commercial route to pentaerythritol [115-77-5]. The aldol condensation of three moles of formaldehyde with one mole of acetaldehyde is foUowed by a crossed Cannizzaro reaction between pentaerythrose, the intermediate product, and formaldehyde to give pentaerythritol (57). The process proceeds to completion without isolation of the intermediate. Pentaerythrose [3818-32-4] has also been made by condensing acetaldehyde and formaldehyde at 45°C using magnesium oxide as a catalyst (58). The vapor-phase reaction of acetaldehyde and formaldehyde at 475°C over a catalyst composed of lanthanum oxide on siHca gel gives acrolein [107-02-8] (59). 

Unsaturated aldehydes undergo a similar reaction in the presence of strongly acid ion-exchange resins to produce alkenyUdene diacetates. Thus acrolein [107-02-8] or methacrolein [78-85-3] react with equimolar amounts of anhydride at —10°C to give high yields of the -diacetates from acetic anhydride, useful for soap fragrances. 

Vinyl ethers and a,P unsaturated carbonyl compounds cyclize in a hetero-Diels-Alder reaction when heated together in an autoclave with small amounts of hydroquinone added to inhibit polymerisation. Acrolein gives 3,4-dihydro-2-methoxy-2JT-pyran (234,235), which can easily be hydrolysed to glutaraldehyde (236) or hydrogenated to 1,5-pentanediol (237). With 2-meth5lene-l,3-dicarbonyl compounds the reaction is nearly quantitative (238). 

The Reaction. Acrolein has been produced commercially since 1938. The first commercial processes were based on the vapor-phase condensation of acetaldehyde and formaldehyde (1). In the 1940s a series of catalyst developments based on cuprous oxide and cupric selenites led to a vapor-phase propylene oxidation route to acrolein (7,8). In 1959 Shell was the first to commercialize this propylene oxidation to acrolein process. These early propylene oxidation catalysts were capable of only low per pass propylene conversions (ca 15%) and therefore required significant recycle of unreacted propylene (9—11). 

The reaction is very exothermic. The heat of reaction of propylene oxidation to acrolein is 340.8 kJ /mol (81.5 kcal/mol) the overall reactions generate approximately 837 kJ/mol (200 kcal/mol). The principal side reactions produce acryUc acid, acetaldehyde, acetic acid, carbon monoxide, and carbon dioxide. A variety of other aldehydes and acids are also formed in small amounts. Proprietary processes for acrolein manufacture have been described (25,26). 

The significance of industrial acrolein production may be clearer if one considers the two major uses of acrolein—direct oxidation to acryUc acid and reaction to produce methionine via 3-methyhnercaptopropionaldehyde. In acryUc acid production, acrolein is not isolated from the intermediate production stream. The 1990 acryUc acid production demand in the United States alone accounted for more than 450,000 t/yr (28), with worldwide capacity approaching 1,470,000 t/yr (29). Approximately 0.75 kg of acrolein is required to produce one kilogram of acryUc acid. The methionine production process involves the reaction of acrolein with methyl mercaptan. Worldwide methionine production was estimated at about 170,000 t/yr in 1990 (30). (See Acrylic ACID AND DERIVATIVES AmINO ACIDS, SURVEY.)... 

Acrolein is a highly reactive compound because both the double bond and aldehydic moieties participate in a variety of reactions. 

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). 

Reactions of acrolein with alcohols producing high yields of alkoxypropionaldehyde acetals are also known. Examples of these are displayed in Table 7 (70). The alkoxypropionaldehyde acetals may be useful as solvents or as intermediates in the synthesis of other useful compounds. 

Methyl mercaptan adds to acrolein in neatly quantitative yields in the presence of a variety of basic catalysts (72,73). Other aLkylmercaptopropionaldehydes produced by the reaction of acrolein with a mercaptan are known. Table 8 Hsts a variety of these and their boiling points (74). 

Reaction with Ammonia. Although the Hquid-phase reaction of acrolein with ammonia produces polymers of Htde interest, the vapor-phase reaction, in the presence of a dehydration catalyst, produces high yields of [ -picoline [108-99-6] and pyridine [110-86-4] n.2L mXio of approximately 2/1. 

Diels-Alder Reactions. Acrolein may participate in Diels-Alder reactions as the dieneophile or as the diene (84—89). 

Acrolein a.s Dienophile. The participation of acrolein as the dienophile in Diels-Alder reactions is, in general, an exothermic process. Dienes such as cyclopentadiene and l-dieth5laniino-l,3-butadiene react rapidly with acrolein at room temperature. 

Several Diels-Alder reactions in which acrolein participates as the dienophile are of industrial significance. These reactions involve butadiene or substituted butadienes and yield the corresponding 1,2,5,6-tetrahydroben2aldehyde derivative (THBA) examples are given in Table 9 (90). These products have found use in the epoxy and perfume/fragrance industries. 

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