Acrolein hydration

Tsunoda, T. and Nomura, K. (2002) Process for producing 1,3-propanediol through acrolein hydration and hydrox-ypropanal hydrogenation and active hydration catalysts for use in the process. WO Patent 2002070447, PCX International Applications. 

By dialysis of the primary addition product, the following equilibrium can be forced to the right side yielding water-soluble, S02-free acrolein hydrate [79] ... 

Acrolein dimer may be easily hydrated to a-hydroxyadipaldehyde, [141-31-1] which may then be reduced to 1,2,6-hexanetriol [106-69-4]. 

Another synthesis of Lyral (51) consists of the reaction of myrcene with acrolein to give the myrac aldehyde [37677-14-8] (52). The aldehyde group, which is sensitive to acid hydration conditions with strong acids, has to be protected by formation of the morpholine enamine. The enamine is then hydrolyzed on workup after the acid-catalyzed hydration to produce Lyral (93—95). 

Biological. Microbes in site water converted acrolein to p hydroxypropionaldehyde (Kobayashi and Rittman, 1982). This product also forms when acrolein is hydrated in distilled water (Burczyk et al., 1968) which can revert to acrolein. This suggests water, not site microbes, is primarily responsible for the formation of the aldehyde. When 5 and 10 mg/L of acrolein were statically incubated in the dark at 25 °C with yeast extract and settled domestic wastewater inoculum, complete degradation was observed after 7 d (Tabak et al, 1981). Activated sludge was capable of degrading acrolein at concentrations of 2,300 ppm but no other information was provided (Wierzbicki and Wojcik, 1965). 

Acrolein (CHj=CHCHO, also known as 2-propenal) is a a,P-unsaturated aldehyde that can be transformed reducfively to saturated or unsaturated alcohols by reduction of the C = 0 or C = C double bonds (Claus 1998). In addition, a,P-unsaturated aldehydes may undergo hydration reactions in aqueous solutions. It was observed that, under acidic (pH12) conditions, acrolein is hydrated to 3-hydroxypropanal (Jensen and Hashtroudi 1976). In a natural subsurface environment, where pH may range from 6.5 to 8.5, the hydration rate of acrolein increases with the pH and its half-life decreases. Based on an experiment to analyze effects of iron on acrolein transformation, Oh et al. (2006) note that, under acidic conditions (e.g., pH = 4.4), acrolein disappears rapidly from solution in the presence of elemental iron (Fig. 16.1). Moreover, the formation of... 

Hong and co-workers have described a formal [3-t-3] cycloaddition of a,P-unsaturated aldehydes using L-proline as the catalyst (Scheme 72) [225], Although the precise mechanism of this reaction is unclear a plausible explanation involves both iminium ion and enamine activation of the substrates and was exploited in the asymmetric synthesis of (-)-isopulegol hydrate 180 and (-)-cubebaol 181. This strategy has also been extended to the trimerisation of acrolein in the synthesis of montiporyne F [226],... 

DIELS-ALDER REACTION USING ANHYDROUS AND HYDRATED Mg(II), 550 DBF-BOX-MEDIATED DIELS-ALDER REACTION, 551 DIELS-ALDER REACTIONS WITH SUBSTITUTED ACROLEINS, 552... 

A careful NMR study by the same group has shown that the 1-azaquinolizinium ion in neutral aqueous solution undergoes hydration to yield (241), but the equilibrium is shifted to the aromatic species (234) if the solution is made 0.1 M in acid (Scheme 118). Bicarbonate causes ring opening to afford j8-(2-pyridylamino)acrolein (242), which can be recyclized in acid. Deuteromethanol also adds to the 1-azaquinolizinium ring, in a transannular manner, and triethylamine converts the resulting salt (243) to 4-methoxy-l-aza-4 7-quinolizine (244). 

Girard-T derivatives of chloroacetaldehyde, crotonaldehyde, and acrolein were not stable. Alternative methods were developed based upon the derivative formed by reaction of crotonaldehyde with hydroxylamine, and the formation of the hydrate of chloroacetaldehyde. 

There is also an apparent trend in manufacturing operations toward simplification by direct processing. Examples of this include the oxidation of ethylene for direct manufacture of ethylene oxide the direct hydration of ethylene to produce ethyl alcohol production of chlorinated derivatives by direct halogenation in place of round-about syntheses and the manufacture of acrolein by olefin oxidation. The evolution of alternate sources, varying process routes, and competing end products has given the United States aliphatic chemical industry much of its vitality and ability to adjust to varying market conditions. 

Propanediol is produced either from the reductive hydration of acrolein (Degussa-DuPont process), or through reductive carbonylation of ethylene oxide (Shell process), or through fermentation of glucose via glycerol (DuPont-Genencor process). 

In ambient air, the primary removal mechanism for acrolein is predicted to be reaction with photochemically generated hydroxyl radicals (half-life 15-20 hours). Products of this reaction include carbon monoxide, formaldehyde, and glycolaldehyde. In the presence of nitrogen oxides, peroxynitrate and nitric acid are also formed. Small amounts of acrolein may also be removed from the atmosphere in precipitation. Insufficient data are available to predict the fate of acrolein in indoor air. In water, small amounts of acrolein may be removed by volatilization (half-life 23 hours from a model river 1 m deep), aerobic biodegradation, or reversible hydration to 0-hydroxypropionaldehyde, which subsequently biodegrades. Half-lives less than 1-3 days for small amounts of acrolein in surface water have been observed. When highly concentrated amounts of acrolein are released or spilled into water, this compound may polymerize by oxidation or hydration processes. In soil, acrolein is expected to be subject to the same removal processes as in water. 

Experimental data specifically pertaining to the degradation or transformation of acrolein in soil were not located. Results of studies in aquatic systems suggest that acrolein, at low concentrations, may be subject to aerobic biodegradation in soil or transformation via hydration followed by aerobic biodegradation of the hydrated product (see Section 5.3.2.2). Since acrolein is a very reactive compound, abiotic processes, such as oxidation, may be the most important degradation processes. 

Colloidal Ruthenium.—Ruthenium may be obtained in the colloidal condition by reduction of its salts in aqueous solution by hydrazine hydrate in the presence of gum acacia.5 Other reducing agents may be employed for the same purpose, such as acrolein.6... 

Osmium Hydrosol or Colloidal Osmium is readily prepared by reducing potassium osmate, K20s04, with hydrazine hydrate in the presence of some protective colloid such as gum acacia 2 or lysalbate (or protalbate) of sodium.3 The reduction may be effected with acrolein 4 if desired. 

Zeolites have also been successfully applied in the reverse reaction, i.e. the hydrolysis of ethers to alcohols. A relevant example is the splitting of bis(3-hydroxypropyl)ether. This compound is a by-product in 1,3-propanediol synthesis, which can be performed by hydration of acrolein and reduction of 3-hydroxypropanal (23). In the hydrolysis of bis(3-hydroxypropyl)ether, a 20 weight % aqueous solution of the ether is passed over a ZSM-5 catalyst at 240°C ... 

The Degussa process (now owned by Dupont) starts from acrolein, which is hydrated in the presence of an acidic ion exchanger into 3-hydroxypropanal (3HP, Fig. 8.8 a). The latter is subsequently extracted into isobutyl alcohol and hydrogenated over a Ni catalyst [53]. The overall yield does not exceed 85%, due to competing water addition at the 2-position and ether formation in the initial step. It has been announced that Degussa will supply up 10 kt a-1 to Dupont until the fermentative process of the latter company (see below) comes on stream [54]. 

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