Acetaldehyde from acetic acid

Chemical Uses. In Europe, products such as ethylene, acetaldehyde, acetic acid, acetone, butadiene, and isoprene have been manufactured from acetylene at one time. Wartime shortages or raw material restrictions were the basis for the choice of process. Coking coal was readily available in Europe and acetylene was easily accessible via calcium carbide. 

Sorbic acid is oxidized rapidly in the presence of molecular oxygen or peroxide compounds. The decomposition products indicate that the double bond farthest from the carboxyl group is oxidized (11). More complete oxidation leads to acetaldehyde, acetic acid, fumaraldehyde, fumaric acid, and polymeric products. Sorbic acid undergoes Diels-Alder reactions with many dienophiles and undergoes self-dimerization, which leads to eight possible isomeric Diels-Alder stmctures (12). 

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. 

Most diaziridines are not sensitive towards alkali. As an exception, diaziridines derived from 2-hydroxyketones are quickly decomposed by heating with aqueous alkali. Acetaldehyde, acetic acid and ammonia are formed from (162). This reaction is not a simple N—N cleavage effected intramolecularly by a deprotonated hydroxy group, since highly purified hydroxydiaziridine (162) is quite stable towards alkali. Addition of small amounts of hydroxybutanone results in fast decomposition. An assumed reaction path — Grob fragmentation of a hydroxyketone-diaziridine adduct (163) — is in accord with these observations (B-67MI50800). 

Acetic acid is also produced hy the oxidation of acetaldehyde and the oxidation of n-hutane. However, acetic acid from the carhonylation route has an advantage over the other commercial processes because both methanol and carbon monoxide come from synthesis gas, and the process conditions are quite mild. 

Important Chemicals from Acetaldehyde Acetic Acid... 

Wood chips can also be utilized as such to produce bioethanol. The cellulose and hemicellulose material is hydrolyzed in the presence of acids (H2SO4, HCl, or HCOOH) or enzymes to yield glucose and other monosaccharides [16]. Lignin is separated by filtration as a solid residue and the monosaccharides are fermented to ethanol, which, in turn, is separated from water and catalyst by distillation. Ethanol can be used not only as energy source but also as a platform component to make various chemicals, such as ethene and polyethene. Today green acetaldehyde and acetic acid from wood-derived bioethanol is manufactured by SEKAB Ab, at the Ornskoldsvik Biorefinery of the Future industrial park. 

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 conversion of ethyl alcohol by way of acetaldehyde into acetic acid is the chemical expression equivalent to acetic fermentation. In this process the acetic bacteria utilise atmospheric oxygen in order to bind the hydrogen. That the hydrogen which has to be removed is activated, and not the oxygen (as was formerly thought), is shown by experiments in which oxygen is eaxluded and replaced by quinone the bacteria produce acetic acid from alcohol as before and the quinone is reduced to hydroquinone. 

The cyclohexanone postulated in this scheme should also be photoactive. The series of reactions necessary to produce the acetic acid observed [11] is indeed long but currently the only reasonable explanation of this product. Previous investigators [20, 21] had not reported acetic acid from the photolysis of PET even though they isolated acetaldehyde, although Day and Wiles [25] did report it. Thus, one may reasonably assume that the presence of 1,4-cyclohexandimethanol most likely is required to produce acetic acid, at least in significant amounts. 

Catalysts used to convert ethylene to vinyl acetate are closely related to those used to produce acetaldehyde from ethylene. Acetaldehyde was first produced industrially by the hydration of acetylene, but novel catalytic systems developed cooperatively by Farbwerke Hoechst and Wacker-Chemie have been used successfully to oxidize ethylene to acetaldehyde, and this process is now well established (7). However, since the largest use for acetaldehyde is as an intermediate in the production of acetic acid, the recent announcement of new processes for producing acetic acid from methanol and carbon monoxide leads one to speculate as to whether ethylene will continue to be the preferred raw material for acetaldehyde (and acetic acid). 

Commercially, these acids are produced in several ways (I) oxidation of relevant alcohol—e.g.. acetic acid from ethyl alcohol (2) oxidation of relevant aldehyde—e g. acetic acid from acetaldehyde (3) bacterial... 

The recent dramatic increase in the price of petroleum feedstocks has made the search for high selectivities more urgent. Several new processes based on carbon monoxide sources are currently competing with older oxidation processes.103,104 The more straightforward synthesis of acetic acid from methanol carbonylation (Monsanto process) has made the Wacker process obsolete for the manufacture of acetaldehyde, which used to be one of the main acetic acid precursors. Several new methods for the synthesis of ethylene glycol have also recently emerged and will compete with the epoxidation of ethylene, which is not sufficiently selective. The direct synthesis of ethylene... 

As many as 70 products were at one time produced commercially from ethanol. Some of these downstream products are butanol, 2-ethyl hexanol, crotonaldehyde, butyraldehyde, acetaldehyde, acetic acid, butadiene, sorbic acid, 2-ethylbutanol, ethyl ether, many esters, ethanol-glycol ethers, acetic anhydride, vinyl acetate, ethyl vinyl ether, even ethylene gas. Many of these products are now more economically made from other feedstocks such as ethylene for acetaldehyde and methanol-carbon monoxide for acetic acid. Time will tell when a revival of biologically-oriented processes will offer lower-cost routes to at least the simpler products. 

The incorporation of [2-14C]pyruvate and [l-14C]acetate into sugars 17 and 18 was investigated.27 Oxidation of the methyl glycosides of sugar 17 with periodate yielded acetaldehyde from the 1-hydroxyethyl branch. The acetaldehyde (2,4-dinitrophenyl)hydrazone was further oxidized by Kuhn-Roth oxidation to acetic acid, which was degraded by the Schmidt reaction to methylamine and carbon dioxide. Periodate oxidation of the methyl glycosides of sugar 18 produced acetic acid from the C-acetyl branch. The acetic acid was isolated, and purified as 1-acetamidonaphthalene. 

C. A. McDowell and J. B. Farmer, Fifth Symposium (International) on Combustion, p. 453, op. ciL, have shown the formation of peracetic acid as the principal initial product in the photosensitized and thermal oxidation of acetaldehyde. (See also earlier papers of McDowell and Farmer.) J. Grumcr, ibid, p. 447, also showed that, at low O2 content, C2H4, C He, CO, CH4, CH,OH, CHsCHO, and CH,CH2CHO were important products from propane pyrolysis in the range 350 to 475 C. He also found considerable amounts of acetic acid from the oxidation of CHaCHO in mixtures at 130 to 450 C having about 3 per cent O2. Such I0W-O2 mixtures are, of course, ideal for observing sensitized pyrolysis reactions. 

From the mass spectrometric data and Eqs. (27) and (28), it is possible to calculate the relative current due to the formation of caibon dioxide, acetaldehyde and finally acetic acid from the ethanol oxidation reaction. These partial currents are shown in Fig. 36 for Pt/C, PtRu/C and PtsSn/C catalysts. " This figure clearly presents the efficiency of the three different catalysts towards the formation of reaction products resulting from the electro-oxidation of ethanol. This quantitative analysis allows us to evaluate the total number of exchanged electrons during the oxidation reaction and the global current efficiency (Aq) and product yield (Wq) of the reaction calculated from the total charge involved for each partial current (Table 4). 

An aqueous solution containing ethyl alcohol in water is fermented to produce dilute acetic acid. The feed mixture (the ethanol solution and the bacteria that make the fermentation occur) and a>r are fed at a temperature Tq. The product solution contains ethanol, acetaldehyde (CH CHO), acetic acid, and water. All liquid and gaseous effluents are at temperature T. The variables involved in the process are n (mol feed solution), x (mol eihanol/mol feed solution), n i (mol air fed). (percent excess air),nah, (gram-moles of ethanol, acetaldehyde, acetic acid, and water, respectively, in the product mixture), Hox, n (gram-moles of oxygen and nitrogen, respectively, emerging from the reactor), 7 , 7, and 0(kJ heat transferred . 

The direct production of acetic acid from synthesis gas [80] instead of methanol as feedstock has demonstrated selectivities up to 80% using rhodium fixed-bed catalysts with Group IIIA-VIIIA promoters and alkaline metals. Other C2 compounds were also formed (acetaldehyde, ethanol, and ethyl acetate) [129],... 

Krampitz and Hardebeck (48) and Hardebeck et al. (19) have found that thermal polyamino acids accelerate the decarboxylation of pyruvic acid. Carbon dioxide (from C-1 of p5n uvate) and acetic acid (from C-2 and C-3 of pyruvate) were the main products. Small amounts of acetaldehyde and acetoin were also detected. The finding of acetic acid as a main product indicates, as the authors pointed out, that an oxidation as well as a decarboxylation must occur. The process is thus somewhat similar to that observed by Fox and Krampitz (46) with... 

Ethanol is used in a variety of fuel, solvent, and chemical applications in industry. Chemical applications have dropped sharply in the last 20 years as more direct routes to products, such as acetaldehyde, acetic acid, ethyl acetate, and ethyl chloride, which were formerly made from ethanol, came on stream. The automotive fuel component, as a component to improve octane rating, is anticipated to have the highest potential for growth. 

Figure 6. Change in product distribution at different levels of ethanol by Candida utilis. Ethanol (A), ethyl acetate (x), acetaldehyde ( ), acetic acid (T). (Reproduced with permission from Ref. 22. Copyright 1984, Science and Technology Letters.)...

Synthetic Acetic Acid.—During the war large quantities of acetic acid have been manufactured synthetically the process being the same as that described under synthetic alcohol in this x>lume, as far as the production of acetalde-hyde. This substance is converted into acetic acid by ox>-gen obtained by the fractional distillation of hquid air in the presence of a catalyst. According to the Drefus patents [e.g. French Patent, No. 479656/1916, and British Patent, No. 105064/1917), which have been operated in the production of acetaldehyde and acetic acid from acetylene, the gas is passed with water a) into solvents in wliicli mercury is soluble, e.g. sulphuric, phosphoric, and acetic acids or (i) into solvents in which acetylene is soluble, e.g. acetone. In the former case, one or more of the following conditions are observed —... 

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