Aldehydes, Ketones, and Alcohols

Hydrogen bonding m carboxylic acids raises their melting points and boiling points above those of comparably constituted alkanes alcohols aldehydes and ketones... 

In the presence of base, di-Z f/-alkyl peroxides are stable, however primary and secondary diaLkyl peroxides undergo oxygen—oxygen bond cleavage, forming alcohols, aldehydes, and ketones (44,66) ... 

Most organic compounds are water-insoluble. Notable exceptions are the lower molecular weight alcohols, aldehydes, and ketones, all known to be "polar" molecules. This characteristic is of importance to firefighting because the specific gravity of the compound will then be a major determinant of the suitability of water for the suppression of fires involving the chemical. 

In general, the methods for protection and deprotection of carboxylic acids and esters are not as convenient as for alcohols, aldehydes, and ketones. It is therefore common to carry potential carboxylic acids through synthetic schemes in the form of protected primary alcohols or aldehydes. The carboxylic acid can then be formed at a late stage in the synthesis by an appropriate oxidation. This strategy allows one to utilize the wider variety of alcohol and aldehyde protective groups indirectly for carboxylic acid protection. 

Depending on the synthetic purpose, the 1,2,4-trioxolane can be transformed to alcohols, aldehydes (and ketones), or carboxylic acids. 

The formation of lipid components in an aqueous phase at temperatures from 370 to 620 K was studied by Rushdie and Simoneit (2001), who heated aqueous solutions of oxalic acid in a steel vessel for 2 days the yield of oxidized compounds reached a maximum (5.5% based on oxalic acid) between 420 and 520 K. A broad spectrum of compounds was obtained, from n-alkanes to the corresponding alcohols, aldehydes and ketones. At higher temperatures, i.e., above 520-570 K, cracking reactions competed with the synthetic reactions. 

The chemical structures of the majority of FMs that have been studied in wastewater treatment are given in Figs. 1-3. Figure 1 shows a variety of FM structures that include alcohols, aldehydes, and ketones, including benzyl acetate (phenylmethyl ester acetic acid), methyl salicylate (2-hydroxy-methyl ester benzoic acid), methyl dihydrojasmonate (3-oxo-2-pentyl-methyl ester cyclopentaneacetic acid), terpineol (4-trimethyl-3-cyclohexene-1-methanol), benzyl salicylate (2-hydroxy-phenylmethyl ester benzoic acid), isobornyl acetate... 

Catalysts suitable specifically for reduction of carbon-oxygen bonds are based on oxides of copper, zinc and chromium Adkins catalysts). The so-called copper chromite (which is not necessarily a stoichiometric compound) is prepared by thermal decomposition of ammonium chromate and copper nitrate [50]. Its activity and stability is improved if barium nitrate is added before the thermal decomposition [57]. Similarly prepared zinc chromite is suitable for reductions of unsaturated acids and esters to unsaturated alcohols [52]. These catalysts are used specifically for reduction of carbonyl- and carboxyl-containing compounds to alcohols. Aldehydes and ketones are reduced at 150-200° and 100-150 atm, whereas esters and acids require temperatures up to 300° and pressures up to 350 atm. Because such conditions require special equipment and because all reductions achievable with copper chromite catalysts can be accomplished by hydrides and complex hydrides the use of Adkins catalyst in the laboratory is very limited. 

Water freezes to ice at 0°C expands by about 10% on freezing boils at 100°C vapor pressure at 0°, 20°, 50°, and 100°C are 4.6, 17.5, 92.5, and 760 torr, respectively dielectric constant 80.2 at 20°C and 76.6 at 30°C dipole moment in benzene at 25°C 1.76 critical temperature 373.99°C critical pressure 217.8 atm critical density 0.322 g/cm viscosity 0.01002 poise at 20°C surface tension 73 dynes/cm at 20°C dissolves ionic substances miscible with mineral acids, alkalies low molecular weight alcohols, aldehydes and ketones forms an azeotrope with several solvents immiscible with nonpolar solvents such as carbon tetrachloride, hexane, chloroform, benzene, toluene, and carbon disulfide. 

The system [RuCl(dppp)j]Vaq. Oxone /CHjClj oxidised primary and secondary alcohols to aldehydes and ketones ([Ru(H30) PW (0)3, ] , RuClj and cis-RuCydmso) also catalysed the reaction) [933], while fra i-RuCl2(dppp)2 and [RuCl(ppy)J+/aq. Li(C10)/CH3Cl3, like c/x-RuC phen), oxidised octan-2-ol to octan-2-one [934], As [RuCKdppp) ] or [Rua(ppy)2] /PhlO/CH3Clj they epoxidised nor-bomene, styrene, stilbene, hex-l-ene and franx-hex-2-ene a number of by-products (alcohols, aldehydes and ketones) were also formed. Kinetic measurements and experiments using suggested the intermediacy of [Ru (0)Cl(dppp)J [932, 935],... 

The correlations involving 0-17 atoms concern dialkylethers, alcohols, aldehydes, and ketones. For the dialkylether oxygen atoms, the appropriate formula is... 

Fig. 7.3 Some aliphatic alcohols, aldehydes and ketones which are important flavour compounds in fruits and vegetables that mainly contribute with green and/or sweet notes...

Table 3. Properties of Selected Terpene Alcohols, Aldehydes, and Ketones...

Lower aliphatic amines are widely used as intermediates for the synthesis of herbicides, insecticides and drugs or can be applied as rubber accelerators, corrosion inhibitors, surface active agents etc. [l]. The most widespread method for the preparation of lower aliphatic amines involves the reaction of ammonia with an alcohol or a carbonyl compound in the presence of hydrogen. The most common catalysts used for reductive amination of alcohols, aldehydes and ketones contain nickel, platinum, palladium or copper as active component [ I — 3 ]. One of the most important issues in the reductive amination is the selectivity control as the product distribution, i.e. the ratio of primary to secondary or tertiary amines, is strongly affected by thermodynamics. 

Alkynes Alcohols Aldehydes and Ketones Acids and Derivatives... 

Wool, which is used as indoor floor covers, clothing and in many other consumer products, can emit a wide variety ofVOCs, many of which have strong odor. Lisovac and Shooter (2003) have shown that several VOCs can be detected in headspace sampling of wool and wool waxes. A number of these are odorous sulfur-containing compounds while the non-sulfur containing components include hydrocarbons, alcohols, aldehydes and ketones, the most prominent of which are 3-methylpen-tane, hexane, methylcylopentane, toluene, 2-methylpentane, ethanol, 1-butanol, pentanal, hexanal acetone, and 2-butanone. 

Organic chemicals that are susceptible to oxidation and are of concern from the perspective of contamination and environmental degradation include aliphatic and aromatic hydrocarbons, alcohols, aldehydes, and ketones phenols, polyphenols, and hydroquinones sulfides (thiols) and sulfoxides nitriles, amines, and diamines nitrogen and sulfur heterocyclic compounds mono- and di-halogenated aliphatics linear alkybenzene-sulfonate and nonylphenol polyethoxylate surfactants and thiophosphate esters. Table... 

Fig. 8.4 (a) shows the response of the oxygenate sensor-1 (Sn02 sensitized with Ti02) towards an alcohol (1-propanol), aldehyde (propanal), ketone (acetone), carbon monoxide (CO) and propane. The sensor is sensitive to the alcohol, aldehyde and ketone but not to CO and propane. Conversely, oxygenate sensor 2 (Sn02 sensitized with 13 wt% Si02/Al203) is less sensitive to the alcohol than aldehyde (Fig. 8.4b). Alcohol formation can thus be estimated from a comparison of the output signals of oxygenate sensors 1 and 2.

Alcohols are oxidized to give ketones or aldehydes, depending on the substitution pattern on the alcohol. Aldehydes and ketones are reduced to alcohols. Notice that, when going from an alcohol to an aldehyde or ketone, two hydrogen atoms (shown in blue in Figure 11.39) are removed, while, at the same time, the carbon-oxygen bond order increases from a single bond to a double bond. In reduction, the reverse is true. 

Effect of Phospholipids on Reaction Volatiles. As would be expected, the inclusion of phospholipids in the reaction mixtures produced many volatiles derived from lipid degradation these included hydrocarbons, alkylfurans, saturated and unsaturated alcohols, aldehydes and ketones. However, two other important observations were made. First, the concentrations of most of the hetero- cyclics, formed by the amino acid + ribose Maillard reaction, were reduced. For most of the major volatiles this reduction was of the order of 40 - 50%, but in the case of thiophenethiol and methyl- furanthiol the reduction was over 65%. This appears to support the findings that in meat and coconut, lipids exert a quenching effect on the amount of heterocyclic compounds formed in Maillard reactions during heat treatment (11,12). Second, and perhaps more important, the addition of phospholipid to the reaction mixtures resulted in the production of large amounts of compounds derived from the interaction of the lipid or its degradation products with Maillard reaction intermediates. 

Monoterpene hydrocarbons, alcohols, aldehydes and ketones are commercially available with sufficient purity. Thus, total syntheses are not required but only conversions of commercial product and synthetic derivatives. 

The aroma of mangosteen is contributed by 52 volatile compounds, 28 of which have been identified. In terms of quantity, the major compounds are (Z)-hex-3-en-l-ol (27%), octane (15%), hexyl acetate (8%) and a-copaene (7%). The main contributors to the mangosteen flavour are hexyl acetate, (Z)-hex-3-enyl-acetate (cis-hex-3-enyl-acetate) and (Z)-hex-3-en-l-ol (MacLeod and Pieris, 1982). The major groups of compounds found in mangosteen aril are alcohols, aldehydes and ketones, esters, hydrocarbons, terpenes, etc. The compounds present are given in Table 19.3. 

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