Aromatic and Aliphatic Alcohols

The rate of oxidation of various diols, dicarboxylic acids, and a-hydroxycar-boxylic acids by silver(II) has been investigated in aqueous perchlorate media. Reactions in the presence of excess substrate (S) were found to be first order in [Ag(II)], the rate law showing pathways attributable to Ag and AgOH as oxidants. However for S = 1,2-ethanediol and 1,3-propanediol, marked curvature in the kinetics profiles is consistent with prior complex formation. The Cr(V) chelate, bis(2-ethyl-2-hydroxybutanato)oxochromate(V), oxidizes the arenediols hydroquinone and 2,3-dihydroxybenzoic acid to form the related quinone and 

Cr(III) species. Both reactions are catalyzed by Cr(V) and proceed via the semiquin-one radical, for which the Cr(IV) and Cr(V) complexes compete.  

The oxidation of n-propanol by aquomanganese(III) ions in perchlorate media is reported to proceed through the formation of alcohol complexes of the type [Mn(C3H70H)] and [Mn(C3H70)]. A complex rate law was proposed which involves terms including association constants and redox rates. This is given in equation (64), from which it was determined that the Mn(OH) acts as the primary 

Various oxoruthenium(IV) complexes have been utilized in the direct and catalytic oxidation of alcohols to aldehydes and ketones. The complex [L5Ru(IV)=0] (L = PPh3,PEt3) reacts with a number of primary alcohols to give the corresponding aldehydes. Rate constants, in H2O, ranging from 0.17 s for MeOH to 170 M s for allyl alcohol, provide a linear correlation 

Carboxylic Acids, Carboxylates, Carbon Dioxide, and Carbon Monoxide 

The biosynthesis of fatty acids produced during alcoholic fermentation is initiated in the yeast cell by the formation of acetylcoenzyme A, which reacts with malonylcoenzyme A to form mainly saturated straight-chained fatty acids with an even number of four to 18 carbon atoms the appearance of relatively low levels of fatty acids with odd numbers of carbon atoms as well as unsaturated fatty acids depends on the fermentation conditions [6]. The volatile fatty acids contribute to the flavour of fermented beverages like wine or beer and their concentration usually lies between 100 and 250 mg 0.1 L p.e. In distilled spirits the concentration of free fatty acids is significantly lower owing to the esterification 

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KU-2 and SG-50 Simple vinyl esters of aliphatic and aromatic alcohols 31... 

Generally, primary aliphatic alcohols are oxidized to their respective aldehydes, secondary aliphatic and aromatic alcohols to the corresponding ketones, and allyl and benzyl alcohols to their carboxylic acid or carboxylate ions. For instance, 2-propanol, acetaldehyde, and methyl-benzoate ions are oxidized quantitatively to acetone, acetate, and terephtalate ion respectively, while toluene is converted into benzoate ion with an 86% yield. Controlling the number of coulombs passed through the solution allows oxidation in good yield of benzyl alcohol to its aldehyde. For diols,502 some excellent selectivity has been reached by changing the experimental conditions such as pH, number of coulombs, and temperature. 

The alcohol dehydrogenases are zinc metalloenzymes of broad specificity. They oxidize a wide range of aliphatic and aromatic alcohols to their corresponding aldehydes and ketones, using NAD+ as a coenzyme (see equation 16.1). The two most studied enzymes are those from yeast and horse liver. The crystal structures... 

In the oxidation of mono-alcohols, in particular aliphatic and aromatic alcohols, Au/ metal oxides have attracted more attention than Au NPs supported on activated carbon (AC) owing to the relatively higher catalytic activity and because of the... 

There are two principal classes of alkylzinc compounds containing a zinc-oxygen bond, that is, those derived from aliphatic and aromatic alcohols (commonly called alkylzinc... 

UV and fluorescent spectroscopy can be employed down to 190 nm because there is no solvent interference. Mass spectrometry is easy because the water provides good ionization. Flame ionization detection (FID) is of particular interest because potentially it offers a sensitive and universal detector. A number of different interfaces have been used, including heated capillaries, which have been examined by Miller and Hawthorne [62], Ingelse et al. [63], and others [64, 65], who separated a range of analytes including alcohols, amino acids, and phenols. An alternative method employing a cold nebuliza-tion of the eluent has been introduced by Bone et al. [66]. They were able to detect both aliphatic and aromatic alcohols, polymers, carbohydrates, parabens, and steroids. 

The Oppienauer reaction has been applied in the conversion of aliphatic and aromatic alcohols. The alcohol, a high-boiling aldehyde (such as cinnamaldehyde), and aluminum alkoxide catalyst are heated, and the volatile aldehyde is removed as it is formed. 

The use of aliphatic and aromatic alcohols, amines, and carboxylic acids as proton donor molecules with DTBN reveals that whereas the X-H protons are shifted to low frequency by the radical the C-H protons, other than X-H, are moved to high frequency (223) (Table X). These high frequency shifts are shown to be characteristic of protic molecules and demonstrate conformational or geometrical dependences. Thus, protons lying on a zig-zag path from the -OH or -NH... 

Other thermophilic enzymes from archaea may be used for analytical and preparative purposes. For instance, the glucose dehydrogenase from S. solfataricus [70] may serve as a suitable tool for glucose determination, whereas the relatively broad substrate spectrum of the esterase from S. acidocaldarius (catalyzes the acyl transfer to various alcohols and amines [71]) or of the alcohol dehydrogenase from S. solfataricus (oxidizes various aliphatic and aromatic alcohols [72]) makes these enzymes rather attractive for... 

Hexaamminecobalt(Ill) ion exhibits two absorption maxima at 475 and 340 nm with extinction coefficients of 58 and 49, respectively. The solubility of the chloride form in water at 20° is 0.26 moles/L. The solubility of the acetate salt is about 1.9 moles/L at 20°. In addition, it has fair solubility in aliphatic and aromatic alcohols. 

Both aliphatic and aromatic alcohols, as well a s unsaturated alcohols, are oxidized in the liquid phase with argentic oxide in nitric or acetic acid at temperatures from -10 through 60 °C [5S6]. 

Other oxidants of hexavalent chromium are chromyl chloride and di-/er/-butyl chromate. Chromyl chloride adsorbed on alumina-silica gel from its solution in dichloromethane oxidizes aliphatic and aromatic alcohols at room temperature within hours in 77-100% yields [675]. Di-tert-butyl chromate, prepared in situ from chromyl chloride in tert-butyl alcohol at -70 °C, gives comparable results under similar conditions [674. Di-tert-butyl chromate, prepared from chromium trioxide and tert-butyl alcohol, oxidizes primary aliphatic and aromatic alcohols to the corresponding aldehydes even at low temperatures (1-2 °C) [677, 678]. 

Another approach to designing shape-selective heterogeneous oxidation catalysts was to use redox metal oxides as the pillaring agents in the preparation of pillared clays. These redox pillared clays have been used for a number of selective oxidations. Chromium pillared montmorillonite (Cr-PILC) is an effective catalyst for the selective oxidation of alcohols with tert-butyl hydroperoxide. 7 Primary aliphatic and aromatic alcohols are oxidized to the aldehydes in very good yields. Secondary alcohols are selectively oxidized in the presence of a primary hydroxy group of a diol to give keto alcohols in excellent yields (Eqn. 21.12). 2... 

Depending on the catalyst system and the chosen reaction conditions, aliphatic and aromatic alcohols can in general act as substrates for oxidative carbonylations. In principle this reaction type can occur in the presence of metal ions which are able to oxidize CO in the presence of an alcohol function. As already mentioned above, it is also here necessary to carry out the reaction in the presence of a suitable reoxidant in order to establish a catalytic cycle process. Preferably that may be another metal salt, for example CuCU- Typical products and side products which are observed in the oxidative carbonylation of alcohols are alkyl and aryl carbonates, oxalates, formates, haloformates, acetals, and carbon dioxide. 

The strategy of derivatisation is illustrated by the example in Fig. 6.14, which shows the separation of the enantiomers of aliphatic and aromatic alcohols on tri-benzoylcellulose as a CSP [95]. 

Davydov et al. [46] used IGC to determine several adsorption thermodynamic properties (equilibrium constants and adsorption heats) for the adsorption of organic compounds on C q crystals, and compared them with those obtained for graphitized carbon black. The adsorption potential of the surface of fiillerene crystals was much lower than that of a carbon black surface. The dispersive interaction of organic molecules with C q is much weaker than with carbon black. The adsorption equilibrium constant for alkanes and aromatic compounds is therefore lower in the case of fullerenes. Aliphatic and aromatic alcohols as well as electron-donor compounds such as ketones, nitriles and amines were adsorbed more efficiently on the surface of fiillerene crystals. This was taken as proof that fiillerene molecules have electron-donor and electron-acceptor properties, which is in agreement with the results of Abraham et al. [44]... 

These catalysts were screened with a range of aliphatic and aromatic alcohols, namely 1, 2 3-pentanol, geraniol, benzyl alcohol, 2 4-hydroxybenyl alcohol, 2-thiophene methanol and sec-phenethyl alcohol. Selected catalysts from the range were also used in the larger scale autoclave test programme. 

A novel glycoside, taxicatin (280) was isolated from the leaves of T.baccata (215-218). The glycosides of aliphatic and aromatic alcohols, as well as of monoterpene alcohols and eugenol have been detected in Taxaceae (219). Recently we have isolated betuloside (283) from T. baccata, reported its absolute stereochemistry and have found it to possess hepatoprotective activity (220). Table 9 lists various glycosides and other sugar derivatives isolated from the genus Taxus. 

A second copper-enzyme which has demonstrated large potential in the catalytic oxidation of alcohols is laccase (15). This blue-copper, one-electron transfer, enzyme requires mediators to extend its catalytic action. Significant progress in its use has been made in the last five years and an overview thereof will be given as well. Finally the class of dinuclear-copper oxidases, catechol oxidases and tyrosinases, and mimics thereof, have shown to be of limited use in the oxidation of aliphatic and aromatic alcohols. Their potential lies in the oxidation of ort/io-diphenols to the corresponding... 

Various aliphatic and aromatic alcohols were oxidized with excellent yields, ranging from 82 to 99%, using this procedure and the results are shown in Table XV. 

Trimellitates are the esters of trimellitic anhydride (1,2,4-benzenetricarboxy-lic acid anhydride) and are noted for their low volatility. The most frequently used are trioctyl trimellitate (TOTM) and tri-isononyl trimellitate (TINTM). They are included in plastics which have to function at high temperatures for long periods and for PVC cable insulation in combination with phthalates. Phosphorous oxychloride reacts with various aliphatic and aromatic alcohols and phenols (triphenylphosphate) to produce triesters. Tricresyl phosphate was patented as a plasticizer for PVC in 1933, but was later found to be highly toxic and replaced. In addition to their role as plasticizers, phosphate esters, particularly triphenyl phosphate, function as flame retardants. 

Partial Oxidation Reactions. Oxidation is used in industry for producing aliphatic and aromatic alcohols, aldehydes, ketones and acids. Generally, oxidation involves splitting of C-C or C-H bonds and formation of C-0 bonds. For example, the partial oxidation of hydrocarbons by molecular oxygen, to form oxygenates that are used as building blocks in the manufacturing of plastics and synthetic fibers, is an important process in the chemical industry. 

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