Acetic acid from ethanol

The balanced equation for production of acetic acid from ethanol is... 

The production of vinegar from ethanol, gluconic acid from glucose and many steroids are examples of currently used industrial-scale bioconversions. The production of acetic acid from ethanol is characteristic of Acetobacter or Gluconobacter species. One gram of ethanol theoretically produces 1.304 g acetic acid 34). Aspergillus,... 

Whole-cell based biocatalysis utilizes an entire microorganism for the production of the desired product. One of the oldest examples for industrial applications of whole-cell biocatalysis is the production of acetic acid from ethanol with an immobilized Acetobacter strain, which was developed nearly 200 yr ago. The key advantage of whole-cell biocatalysis is the ability to use cheap and abundant raw materials and catalyze multistep reactions. Recent advances in metabolic engineering have brought a renaissance to whole-cell biocatalysis. In the following sections, two novel industrial processes that utilize whole-cell biocatalysis are discussed with emphasis on the important role played by metabolic engineering. 

The acetic acid bacteria produce acetic acid from ethanol hy two enzyme-catalyzed reactions of memhrane-hound alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH). In addition, some acetic acid bacteria can oxidize various sugars and sugar alcohols. These reactions are all incomplete oxidations because the oxidation products are usually accumulated in large amounts in the bacterial beers. Both ADH and ALDH have pyrroloquinohne quinone (PQQ) bound as a prosthetic group and are linked to the respiratory chain in the cytoplasmic membrane (O Fig. 1.3). A second set of NAD(-P) -dependent ADHs and ALDHs is found in the cytoplasm of acetic add bacteria. These latter two enzymes have much lower specific activities than those of the PQQ-enzymes and are not involved in acetic add production (seeO Fig. 1.3). 

The strains of the genus Asaia were first found and isolated from flowers collected in Indonesia. In the beginning, the distribution of the Asaia strains was supposed to be restricted only to the tropical zone, that is, in Thailand, the Philippines, and Indonesia (Yamada and Yukphan 2008). However, the Asaia strains were isolated in the temperate zone, in Japan (Suzuki et al. 2010). The strains of the genus Asaia produced no or a very small amount of acetic acid from ethanol and did not grow in the presence of 0.35 % acetic acid (v/w). 

The production of acetic acid from butane is a complex process. Nonetheless, sufficient information on product sequences and rates has been obtained to permit development of a mathematical model of the system. The relationships of the intermediates throw significant light on LPO mechanisms in general (22). Surprisingly, ca 25% of the carbon in the consumed butane is converted to ethanol in the first reaction step. Most of the ethanol is consumed by subsequent reaction. 

Witt and Kopetschni report a melting point of 295-296° (dec.). This compound may be recrystallized from glacial acetic acid or ethanol. 

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. 

CO to generate acetic acid in aqueous conditions by means of several catalysts (Table 2.2).26 RhCl3 catalyzed the direct formation of methanol and acetic acid from methane, CO, and O2 in a mixture of perfluorobutyric acid and water with a turnover rate at approximately 2.9 h-1 based on Rh at 80-85°C.27 Under similar conditions, ethane was more active and gave ethanol, acetic acid, and methanol. 

Ethyl acetate is an oxygenated solvent widely used in the inks, pharmaceuticals and fragrance sectors. The current global capacity for ethyl acetate is 1.2 million tonnes per annum. BP Chemicals is the world s largest producer of ethyl acetate. Conventional methods for the production of ethyl acetate are either via the liquid phase esterification of acetic acid and ethanol or by the coupling of acetaldehyde also known as the Tischenko reaction. Both of these processes require environmentally unfriendly catalysts (e.g. p-toluenesulphonic acid for the esterification and metal chlorides and strong bases for the Tischenko route). In 1997 BP Chemicals disclosed a new route to produce ethyl acetate directly from the reaction of ethylene with acetic acid using supported heteropoly acids... 

In the presence of bis(acetylacetonato)nickel, a-dicarbonyl compounds readily add at the nitrile group of 4-R-substituted l,2,5-oxadiazole-3-carbonitriles 219 to form enaminofurazans 220. The adducts obtained from 4-amino-3-cyanofurazan underwent intramolecular cyclization upon heating with acetic acid in ethanol to give furazano[3,4- ]pyridine 221 derivatives in high yields (Scheme 51) <2001RCB1280>. 

Figure 3.10 XPS spectra in the range from 150 to 200 eV, showing the Zr 3d and Si 2s peaks of the 7.r02/Si02 catalysts after calcination at 700 °C. All XPS spectra have been corrected for electrical charging by positioning the Si 2s peak at 154 eV. The spectra labeled nitrate correspond to the catalysts prepared by incipient wetness impregnation with an aqueous solution of zirconium nitrate, and the spectrum labeled ethoxide to that prepared by contacting the support with a solution of zirconium ethoxide and acetic acid in ethanol. The latter preparation leads to a better Zr02 dispersion over the Si02 than the standard incipient wetness preparation does, as is evidenced by the high Zr 3d intensity of the bottom spectrum (adapted from Meijers et at, [33]).

Table 9.4 8 values for ethanols and acetic acids from various sources... 

Figure 18. Correlations between the solubility of cmchonidme and the reported empirical polarity (A) and dielectric constants (B) of 48 solvents [66]. Those solvents are indicated by the numbers in the figures 1 cyclohexane 2 n-pentane 3 n-hexane 4 triethylamine 5 carbon tetrachloride 6 carbon disulfide 7 toluene 8 benzene 9 ethyl ether 10 trichloroethylene 11 1,4-dioxane 12 chlorobenzene 13 tetrahydrofuran 14 ethyl acetate 15 chloroform 16 cyclohexanone 17 dichloromethane 18 ethyl formate 19 nitrobenzene 20 acetone 21 N,N-drmethyl formamide 22 dimethyl sulfoxide 23 acetonitrile 24 propylene carbonate 25 dioxane (90 wt%)-water 26 2-butanol 27 2-propanol 28 acetone (90 wt%)-water 29 1-butanol 30 dioxane (70 wt%)-water 31 ethyl lactate 32 acetic acid 33 ethanol 34 acetone (70 wt%)-water 35 dioxane (50 wt%)-water 36 N-methylformamide 37 acetone (50 wt%)-water 38 ethanol (50 wt%)-water 39 methanol 40 ethanol (40 wt%-water) 41 formamide 42 dioxane (30 wt%)-water 43 ethanol (30 wt%)-water 44 acetone (30 wt%)-water 45 methanol (50 wt%)-water 46 ethanol (20 wt%)-water 47 ethanol (10 wt%)-water 48 water. [Reproduced by permission of the American Chemical Society from Ma, Z. Zaera, F. J. Phys. Chem. B 2005, 109, 406-414.]...

Equations 2-27 and 2-33 and Fig. 2-2 describe the much greater difficulty of performing a successful polymerization compared to the analogous small-molecule reaction (such as the synthesis of ethyl acetate from acetic acid and ethanol). Consider the case where one needs to produce a polymer with a degree of polymerization of 100, which is achieved only at 99% reaction. Running the polymerization to a lower conversion such as 98%, an excellent conversion for a small-molecule synthesis, results in no polymer of the desired molecular weight. Further, one must almost double the reaction time (from 450 min to 850 min in Fig. 2-2) to achieve 99% reaction and the desired polymer molecular weight. For the small molecule reaction one would not expend that additional time to achieve only an additional 1 % conversion. For the polymerization one has no choice other than to go to 99% conversion. 

In this preparation the nitroso compound may be added in solution form to a solution to the amine at low temperature. The solvent may be a suitable mixture of acetic acid and ethanol as well as acetic acid alone. The product may also be extracted from a reaction mixture diluted with water by use of ether [32]. Purification of the final product may be carried out by chromatography on an alumina column. 

NNH2,CH3N303 mw 105.06 N 39.98% OB to C02 —7.61% colorl platelets (from ethanol plus eth) mp 158.4—.8° (decompn). Freely sol in acet, acetic acid and ethanol sol in hot w (forms cyanic acid and nitroamide) si sol in benz, chlf and petr eth. CA Registry No [556-89-8]. Prepn is by dehydration of Urea Nitrate with coned sulfuric acid. The compd can be detonated but is not sensitive to percussion or heating (Ref 7)... 

Extraction is an essential step when analyzing solid samples. In some cases homogenization with a solvent suffices, but in others the sample must first be coimninuted. Water, solutions of acetic acid or sodium chloride, or more complex saline solutions are used as solvents. Mixtures of water and methanol or water and ethanol are also employed. The choice of solvent depends on the degree of selectivity desired in the extraction and whether the extraction yield is intended for quantitative analysis. Optimization of the extraction procedure is required in all cases, to fit the nature of the sample to be analyzed and the range of molecular weights of the peptides to be separated. For example, water has been used as the extraction solvent for cheese (33) and legumes (34). Saline solutions have been utilized to extract peptides from meat (35-38) and flour (39,40). Benedito de Barber et al. (41) examined differences in the extractability of amino acids and short peptides in various solvents (1M acetic acid, 70% ethanol, and distilled water) they concluded that extraction with 1M acetic acid yielded the maximum amino acid and peptide contents. 

Fig. 6 RI chromatogram of standard solution. 1 = sucrose 2 = citric acid 3 = glucose 4 = fructose 5 = lactic acid 6 = acetic acid 7 = ethanol. (From Ref. 36.)...

The carbonylation of methanol, dimethyl ether and methyl acetate using as catalyst precursors [RuI2(CO)4] and [Ru(acac)3] (88) with Nal, HI or Mel as promoter has been reported.381 The major products were ethanol from methanol, methyl acetate from dimethyl ether, and acetic anhydride plus acetic acid from methyl acetate (equations 67-69). 

Orthoamide 123 cleanly reduced mercuric acetate in ethanol at 25°C to mercury or mercurous acetate. The organic product formed is guanidinium salt 129 lX= OAc). Similarly, iodine in methanolic potassium carbonate at 25°C oxidized orthoamide 123 to guanidinium iodide 129 (X= I). On the other hand, orthoamide 122 does not react with mercuric acetate even in boiling ethanol. Syn-elimination of mercury and acetic acid from complex 130 must be slow but anti-elimination from complex 131 (Y= l or HgX2) must occur readily. 

Allow a mixture of 0.5 g of the tertiary amine and 0.5 ml of colourless methyl iodide to stand for 5 minutes. If reaction has not occurred, warm under reflux for 5 minutes on a water bath and then cool in ice-water. The mixture will generally set solid if it does not, wash it with a little dry ether and scratch the sides of the tube with a glass rod. Recrystallise the solid product from absolute ethanol or methanol, ethyl acetate, glacial acetic acid or ethanol-ether. 

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