Acetaldehyde from ethane

Give a sequence of reactions leading to the formation of acetaldehyde from ethane starting with the reaction of hydroxyl radical. 

Examples for necessary process improvements through catalyst research are the development of one-step processes for a number of bulk products like acetaldehyde and acetic acid (from ethane), phenol (from benzene), acrolein (from propane), or allyl alcohol (from acrolein). For example, allyl alcohol, a chemical which is used in the production of plasticizers, flame resistors and fungicides, can be manufactured via gas-phase acetoxylation of propene in the Hoechst [1] or Bayer process [2], isomerization of propene oxide (BASF-Wyandotte), or by technologies involving the alkaline hydrolysis of allyl chloride (Dow and Shell) thereby producing stoichiometric amounts of unavoidable by-products. However, if there is a catalyst... 

The most important reaction based on Pdn-catalysis is the Wacker oxidation [171], which is used industrially for the synthesis of acetaldehyde, starting from ethane. This process can be combined with a Heck reaction and has been used by Tietze and coworkers [172] for an efficient enantioselective synthesis of vitamin E (6/1-... 

Acetaldehyde or ethanal is the second member of the series and corresponds to ethyl alcohol from which it is made by oxidizing with chromic acid (potassium bichromate and sulphuric acid). 

Supported metal oxides are currently being used in a large number of industrial applications. The oxidation of alkanes is a very interesting field, however, only until recently very little attention has been paid to the oxidation of ethane, the second most abundant paraffin (1). The production of ethylene or acetaldehyde from this feed stock is a challenging option. Vanadium oxide is an important element in the formulation of catalysts for selective cataljdic reactions (e. g. oxidation of o-xylene, 1-3, butadiene, methanol, CO, ammoxidation of hydrocarbons, selective catalytic reduction of NO and the partial oxidation of methane) (2-4). Many of the reactions involving vanadium oxide focus on the selective oxidation of hydrocarbons, and some studies have also examined the oxidation of ethane over vanadium oxide based catalysts (5-7) or reviewed the activity of vanadium oxide for the oxidation of lower alkanes (1). Our work focuses on determining the relevance of the specific oxide support and of the surface vanadia coverage on the nature and activity of the supported vanadia species for the oxidation of ethane. 

The fact that ethane has been found to be so much more readily reacted upon by oxygen than methane to yield larger quantities of formaldehyde than is obtainable from methane, makes it seem that some of the high yields reported from methane may have in most part beeu due to ethane admixed in the hydrocarbon gas used, rather than the attainment of unusually productive operating conditions. This is true of data from experiments in which natural gas had been used for oxidation. The pressure oxidation process producing a mixture of methanol, formaldehyde, and acetaldehyde from natural gas utilizes the hydrocarbons higher than methane, and especially ethane. ... 

Batch Di (3-pentyl) Malate Process Acetaldehyde from Acetic Acid Ethylene by Oxidative Dehydrogenation of Ethane Butadiene to n-Butyraldehyde and n-Butanol Methacrylic Acid to Methylmethacrylate Coproduction of Ethylene and Acetic Acid from Ethane Methylmethacrylate from Propyne Mixed-C4 Byproduct Upgrade Hydrogen Peroxide Manufacture Di-tem fljy-butyl-peroxide Manufacture Vinyl Acetate Process PM Acetate Manufacture Propoxylated Ethylenediamine Petroleum Products Fuel Additives for Cleaner Emissions Gas Manufacture... 

As a consequence, an ESR reformed stream coming from a CR contains not only hydrogen but also CO2, CO and CH4, in addition to acetaldehyde, ethylene, ethane, etc. 

For the formation of ethanethiol and diethylsulphide from ethanol, hydrogen and gaseous sulphur the reaction mixture is assumed to contain the initial constituents as well as ethanethiol, diethylsulphide, hydrogen sulphide, diethylether, acetaldehyde, ethylene, ethane and water. The results of calculating the equimolar composition of the initial mixture (C2H50H H2 S2(g) = 1 1 i) at 80 atm pressure are also included in Tabic 5 for the above three types of mixtures (i-i, i-r, r-r) in the form of numbers of moles of individual constituents at the respective temperatures. 

The conjugate base derived from ethanal (acetaldehyde) is more stable than the conjugate base of ethane. Explain why. 

The conjugate base derived from ethanal (acetaldehyde) is more stable than the conjugate base of ethane. Explain why. Answer The conjugate base of ethanal is resonance stabilized, and the conjugate base of ethane is not. 

The photochemistry of the ethane and higher hydrocarbon oxidation in the atmosphere follows similar reaction paths as for methane, although reactions occur faster because of the higher reactivity of these molecules [33, 36]. In the case of ethane, there can be a net production of five ozone molecules per ethane molecule consumed, if sufficient NO is present in the atmosphere. The cycle of reactions, cycle C4, that produces ozone from ethane is shown in Box 5.3. The compound peroxyacetyl nitrate, CH3(C=0)02N02, which appears in C4 is a strong phytotoxicant and air pollutant, better known by the acronym PAN [37]. The compound, CH2O, is formaldehyde and CH3CHO is acetaldehyde. 

Acetaldehyde [75-07-0] (ethanal), CH CHO, was first prepared by Scheele ia 1774, by the action of manganese dioxide [1313-13-9] and sulfuric acid [7664-93-9] on ethanol [64-17-5]. The stmcture of acetaldehyde was estabhshed in 1835 by Liebig from a pure sample prepared by oxidising ethyl alcohol with chromic acid. Liebig named the compound "aldehyde" from the Latin words translated as al(cohol) dehyd(rogenated). The formation of acetaldehyde by the addition of water [7732-18-5] to acetylene [74-86-2] was observed by Kutscherow] in 1881. 

Acetaldehyde. Until the early 1970s, the maia use of iadustrial ethanol was for the production of acetaldehyde [75-07-0]. By 1977, the ethanol route to acetaldehyde had largely been phased out ia the United States as ethylene and ethane became the preferred feedstocks for acetaldehyde production (286—304). Acetaldehyde usage itself has also changed two primary derivatives of acetaldehyde, acetic acid, and butanol, are now produced from feedstocks other than acetaldehyde. Acetaldehyde is stiU produced from ethanol ia India. 

Some of these difficulties can be circumvented. In particular a cavity-type Stark effect spectrograph has been built which seems capable of yielding relative intensities of near-by lines to within two or three per cent.32 Barrier values for acetaldehyde and fluoro-ethane have been obtained which are in excellent agreement with those from the frequency method described below. From Eq. (1) it can be seen that the error in v is... 

Because hydrogen can easily be removed from a reaction stream, many dehydrogenations have been studied. These include dehydrogenation of methane to carbon,326 ethane to ethene,327,328 propane to propene,329 n-butane to butenes,330 isobutane to isobutene,331,332 cyclohexane to benzene,332-334 meth-ylcyclohexane to toluene 335 n-heptane to toluene,336 methanol to formaldehyde,330 and ethanol to acetaldehyde.337... 

Carbonyl group of the aldehyde decreases the BDE of the adjacent C—H bond. This is due to the stabilization of the formed acyl radical, resulting from the interaction of the formed free valence with Tr-electrons of the carbonyl group. For example, DC—H = 422kJmol 1 in ethane and D( n 373.8 kJ mol 1 in acetaldehyde. The values of Dc H in aldehydes of different structures are presented in Table 8.1. In addition, the values of the enthalpies of acylperoxyl radical reactions with aldehydes were calculated (D0 H= 387.1 kJ mol-1 in RC(0)00 H). 

We have delineated viable coordinated ligand reactions and their attendant intermediates for the stoichiometric conversion of CO ligands selectively to the C2 organics ethane, ethylene, methyl (or ethyl) acetate, and acetaldehyde. We now outline results from three lines of research (1) T -Alkoxymethyl iron complexes CpFe(C0)2CH20R (2) are available by reducing coordinated CO on CpFe(C0)3+ (1) [Cp = r -CsHs]. Compounds 2 then form t -alkoxyacetyl complexes via migratory-insertion (i,e. CO... 

A very high activity of mitochondrial aldehyde dehydrogenases (together with its low ensures very efficient oxidation in the liver so that the concentration of acetaldehyde in blood remains very low. Nonetheless, it is possible that some of the pathological effects of ethanol are due to acetaldehyde (ethanal). In contrast, a large proportion of the acetate escapes from the liver and is converted to acetyl-CoA by acetyl-CoA synthetase in other tissues ... 

Table 8.1 shows the stochastic model solution for the petrochemical system. The solution indicated the selection of 22 processes with a slightly different configuration and production capacities from the deterministic case, Table 4.2 in Chapter 4. For example, acetic acid was produced by direct oxidation of n-butylenes instead of the air oxidation of acetaldehyde. Furthermore, ethylene was produced by pyrolysis of ethane instead of steam cracking of ethane-propane (50-50 wt%). These changes, as well as the different production capacities obtained, illustrate the effect of the uncertainty in process yield, raw material and product prices, and lower product... 

Rb2Mo04 This catalyst was found to be much more active and selective than the divalent metal molybdates. As shown in Figure 2, very little decay was obsei ved in the conversion of ethane. In contrast with the previous catalysts, acetaldehyde was the main product of partial oxidation at 823 K it was fornied with a selectivity of 23-24%. The selectivity for ethylene was 10-13%. As it appears from Figure 2, the yield of acetaldehyde formation was about 5 times higher than on Mo03/Si02... 

Aldol condensation reaction may be either acid or base catalysed. However, base catalysis is more common. The product of this reaction is called an aldol, i.e. aid from aldehyde and ol from alcohol. The product is either a P-hydroxyaldehyde or P-hydroxyketone, depending on the starting material. For example, two acetaldehyde (ethanal) molecules condense together in the presence of an aqueous base (NaOH), to produce 3-hydroxybutanal (a P-hydroxyaldehyde). 

---