To Alcohols and Alkanes

Chemical Properties. Like neopentanoic acid, neodecanoic acid, C2QH2QO2, undergoes reactions typical of carboxyHc acids. For example, neodecanoic acid is used to prepare acid chlorides, amides (76), and esters (7,11,77,78), and, like neopentanoic acid, is reduced to give alcohols and alkanes (21,24). One area of reaction chemistry that is different from the acids is the preparation of metal salts. Both neopentanoic acid and neodecanoic acid, like all carboxyHc acids, can form metal salts. However, in commercial appHcations, metal salt formation is much more important for neodecanoic acid than it is for neopentanoic acid. 

One of the exciting results to come out of heterogeneous catalysis research since the early 1980s is the discovery and development of catalysts that employ hydrogen peroxide to selectively oxidize organic compounds at low temperatures in the liquid phase. These catalysts are based on titanium, and the important discovery was a way to isolate titanium in framework locations of the inner cavities of zeolites (molecular sieves). Thus, mild oxidations may be run in water or water-soluble solvents. Practicing organic chemists now have a way to catalytically oxidize benzene to phenols alkanes to alcohols and ketones primary alcohols to aldehydes, acids, esters, and acetals secondary alcohols to ketones primary amines to oximes secondary amines to hydroxyl-amines and tertiary amines to amine oxides. 

Alkanes are oxidized first to alcohols and then to ketones6,34,45,51 52 as shown in Fig. 6.6. The order of reactivity is tertiary C—H > secondary C—H > primary C-H. In many cases oxidation of primary C—H bonds is below detection.52... 

Spectra of the greasy wool are more complicated than in the previous study. In negative ion mode, different fatty acids, fatty alcohols and alkanes are detected, whereas the positive ion mode shows mainly the presence of cholesterol and the cholesterol oxidation product (Figure 15.6). These ions are attributed to the presence of wool wax on the surface of raw wool. 

However, (Ph3P)2Rh(CO)Cl on alumina or activated carbon were effective hydroformylation catalysts under more severe conditions 108). At 148°C and a pressure of 49 atm (CO 37.5 mol%, H2 37.5, propylene 25), good activity was found. The propylene conversion was 30% at a contact time of 0.92 cm3 of reactor void space/cm3 of feed per minute. Isomer ratios of 1.3 to 1.9 1 n iso were realized. By-product formation was low, with <1% conversion to alcohols plus alkanes and 2.2% high-boiling materials. This system was stable for a 300 hour operating time, with no detectable loss of activity or selectivity. 

Alkanes (e.g. adamantane, cyclohexane, toluene) were oxidised to alcohols and cyclohexanol to cyclohexanone by stoich. franx-Ba[Ru(OH)3(0)3]/AcOH, a reaction... 

In our previous review, we attempted to establish some simple relationships among peroxides, ethers, alcohols and alkanes using a limited peroxide data set and a sometimes less than adequate data set for the comparison classes of compounds. The analysis is extended in this volume. The formal reactions, equations 2-5 and 6-9, that illustrate some typical comparisons are shown in Schemes 1 and 2. 

Union Carbide invented the industrial use of highly active ligand-modified rhodium complexes.90-93 [RhH(CO)(PPh3)3], the most widely used catalyst, operates under mild reaction conditions (90-120°C, 10-50 atm). This process, therefore, is also called low-pressure oxo process. Important features of the rhodium-catalyzed hydroformylation are the high selectivity to n-aldehydes (about 92%) and the formation of very low amounts of alcohols and alkanes. Purification of the reactants, however, is necessary because of low catalyst concentrations. 

Fig. 4. Conversion after 2 hours of vigorous stirring of C5 to CIO n-alkanes to alcohols and ketones, carried out at 298 K and 0.1 MPa in a microreactor of 3 ml with 2.4 mmol t.BHP, and 6 mmol paraffin. 8.10 mmol FePc was used in 1.5 ml dichloromethane and 0.1 g FePcY in 1.5 ml acetone.

Exercise 15-24 It is possible to prepare amides from tertiary alcohols and alkane-nitriles, RCN, in concentrated sulfuric acid as the catalyst (Ritter reaction), as illustrated in the equation for the synthesis of W-fe/f-butylethanamide ... 

Alkanes are oxidized to alcohols and ketones. Linear alkanes are oxidized to secondary alcohols and ketones, with good selectivity based on hydrocarbons and H202 (Table IX). 

In a subsequent report, in 2005 [55], the same group described the preparation of imprinted polymer capable of oxidising alcohols and alkanes with 2,6-dichlor-opyridine /V-oxide (86) without mineral acid activation. The polymer was imprinted with a ruthenium porphyrin complex (87) using the diphenylmethana-mine (88) as pseudo-substrate template in order to achieve a shape of the cavity complementary to the substrates, diphenylmethane (89) and diphenylmethanol (84). The reaction, carried out with the imprinted polymer on the diphenylmethanol as substrate, showed a rate enhancement 2.5 higher than with the non-imprinted polymer. In the same conditions, but with diphenylmethane and... 

Selective oxidation of alkanes and benzene derivatives to alcohols and phenols, respectively, are among the most difficult reactions in oxidation catalysis. Therefore, the stoichiometric hydroxylation of alkenes and aromatics performed by a-oxygen at room temperature has aroused great interest as a potential way for developing new steady state catalytic processes for the preparation of these valuable products, similar to the hydroxylation of benzene to phenol. 

In summary, the oxidation of alkanes with iron-based catalysts remains a challenging task. Much progress has been made but the field is still far from mature. Higher efficiencies in the transformation ofhydrocarbons to alcohols and ketones are desirable. 

Much of the work on model systems was stimulated by the observation of Udenfriend and co-workers in 19546S4a,b that a mixture of Fe(II), EDTA, ascorbic acid, and molecular oxygen could hydroxylate arenes to phenols under mild conditions. Udenfriend s reagent also hydroxylates alkanes to alcohols and epoxidizes olefins.670 6 74 The EDTA in Udenfriend s reagent probably reduces the redox potential of the Fe(II)/Fe(III) couple. The ascorbic acid functions as an electron donor, analogous to the cofactor in monooxygenases, and can be replaced by other enediols.672... 

The Udenfiiend system of 1954 was perhaps the first to be specifically presented as a model of a biological process. In this system, Fe(II) is the catalyst, EDTA the ligand, air is the primary oxidant and ascorbic acid provides the reducing equivalents called for in this monooxygenase system. Arenes can be hydroxylated to phenols, alkanes to alcohols, and alkenes to epoxides, although with modest efficiency. The NIH shift was not observed in the model, however. 

The oxidation of alkanes with HjO, to alcohols and ketones has received much attention, as it is usually difficult to realize good selectivities at appreciable conversions [179]. Over TS-1 the process is highly selective (up to 90% selectivity based on the consumption of H O, [181]). At present, it is unresolved whether the reaction proceeds via consecutive one electron steps or via a single two electron step [163]. It is remarkable that an apolar substance such as n-hexane can be oxidized in the presence of polar solvents such... 

H abstractions from ethers, alcohols, and alkanes, are of radical type as evident from the constancy of d. The higher d values for abstractions influenced by phenyl groups can be assigned to lower n values due to electron withdrawing effects, or to underestimation of the group additivity parameters of the radical centres bonded to phenyl groups. 

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