Oxidation of 2-butanol

Subbaraman and Santappa found that with de-aerated solutions the rate equation for the oxidation of 2-butanol is the same as that found by Ball et al. for the oxidation of 2-propanol in the absence of oxygen, i.e. equation (19). 

Measurements in the temperature range 55-70 °C show that the rate coefficient is expressed by 

The mechanism is considered to be the same as that proposed by Ball et al., i.e. reactions (20)-(23). For the silver ion-catalysed oxidation, Subbaraman and Santappa found the rate equation to be 

However, Venkatasubramanian and Sabesan report that the rate is zero order with respect to the substrate, as in most silver ion-catalysed oxidations by peroxo-disulphate. 

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Rohan and Hodnett (52) showed that V supported on Ti02 with H2O2 catalyzes the oxidation of 2-butanol to give methyl ethyl ketone, but the activity is largely attributed to dissolved V. 

A ketone (methyl ethyl ketone) is produced by the oxidation of 2 - butanol. The molar mass of the ketone is ... 

In the case of a secondary alcohol such as 2-butanol or butan-2-ol, the product of oxidation would be a ketone (Figure 4.24). In this case, the oxidation of 2-butanol produces 2-butanone or butan-2-one. 

Chew et al. (1998) observed 2-butanone in a yield of (79 9%) following the NOs-radical-initiated oxidation of 2-butanol. 

Now let s draw the forward scheme. Ethyl bromide is converted into ethyl magnesium bromide, which is then treated with acetaldehyde (to give a Grignard reaction), followed by water work-up, to give 2-butanol. Oxidation of 2-butanol with chromic acid gives 2-butanone, which can then be converted into a cyanohydrin upon treatment with KCN and HCl. And finally, hydrolysis of the cyano group gives the desired product ... 

Direct oxidation yields biacetyl (2,3-butanedione), a flavorant, or methyl ethyl ketone peroxide, an initiator used in polyester production. Ma.nufa.cture. MEK is predominandy produced by the dehydrogenation of 2-butanol. The reaction mechanism (11—13) and reaction equihbtium (14) have been reported, and the process is in many ways analogous to the production of acetone (qv) from isopropyl alcohol. 

The dehydrogenation of 2-butanol is conducted in a multitube vapor-phase reactor over a zinc oxide (20—23), copper (24—27), or brass (28) catalyst, at temperatures of 250—400°C, and pressures slightly above atmospheric. The reaction is endothermic and heat is suppHed from a heat-transfer fluid on the shell side of the reactor. A typical process flow sheet is shown in Figure 1 (29). Catalyst life is three to five years operating in three to six month cycles between oxidative reactivations (30). Catalyst life is impaired by exposure to water, butene oligomers, and di-j -butyl ether (27). 

The oxidation of primary and secondary alcohols in the presence of 1-naphthylamine, 2-naphthylamine, or phenyl-1-naphthylamine is characterized by the high values of the inhibition coefficient / > 10 [1-7], Alkylperoxyl, a-ketoperoxyl radicals, and (3-hydroxyperoxyl radicals, like the peroxyl radicals derived from tertiary alcohols, appeared to be incapable of reducing the aminyl radicals formed from aromatic amines. For example, when the oxidation of tert-butanol is inhibited by 1-naphthylamine, the coefficient /is equal to 2, which coincides with the value found in the inhibited oxidation of alkanes [3], However, the addition of hydrogen peroxide to the tert-butanol getting oxidized helps to perform the cyclic chain termination mechanism (1-naphthylamine as the inhibitor, T = 393 K, cumyl peroxide as initiator, p02 = 98 kPa [8]). This is due to the participation of the formed hydroperoxyl radical in the chain termination ... 

Because the direct electrochemical oxidation of NAD(P)H has to take place at an anode potential of + 900 mV vs NHE or more, only rather oxidation-stable substrates can be transformed without loss of selectivity—thus limiting the applicability of this method. The electron transfer between NADH and the anode may be accellerated by the use of a mediator. At the same time, electrode fouling which is often observed in the anodic oxidation of NADH can be prevented. Synthetic applications have been described for the oxidation of 2-hexene-l-ol and 2-butanol to 2-hexenal and 2-butanone catalyzed by yeast alcohol dehydrogenase (YADH) and the alcohol dehydrogenase from Thermoanaerobium brockii (TBADH) repectively with indirect electrochemical... 

Fig. 6. Schematic representation for the ADH-catalyzed electroenzymatic oxidation of 2-hexene-l-ol and 2-butanol with indirect electrochemical NAD+ regeneration using (3,4,7,8-tetramethyl-l.lO-phenanthroline) iron(II/III) [Fe(tmphen)3] as redox catalyst...

The primary products obtained from 2-butanol are of mechanistic. significance and may be compared with other eliminations in the sec-butyl system 87). The direction of elimination does not follow the Hofmann rule 88) nor is it governed by statistical factors. The latter would predict 60% 1-butene and 40% 2-butene. The greater amount of 2-alkene and especially the unusual predominance of the cis-olefin over the trans isomer rules out a concerted cis elimination, in which steric factors invariably hinder the formation of cis-olefin. For example, the following ratios oicisjtrans 2-butene are obtained on pyrolysis of 2-butyl compounds acetate, 0.53 89, 90) xanthate, 0.45 (S7) and amine oxide, 0.57 86) whereas dehydration of 2-butanol over the alkali-free alumina (P) gave a cisjtrans ratio of 4.3 (Fig. 3). 

Taylor and Flood could show that polystyrene-bound phenylselenic acid in the presence of TBHP can catalyze the oxidation of benzylic alcohols to ketones or aldehydes in a biphasic system (polymer-TBHP/alcohol in CCI4) in good yields (69-100%) (Scheme 117) °. No overoxidation of aldehydes to carboxylic acids was observed and unactivated allylic alcohols or aliphatic alcohols were unreactive under these conditions. In 1999, Berkessel and Sklorz presented a manganese-catalyzed method for the oxidation of primary and secondary alcohols to the corresponding carboxylic acids and ketones (Scheme 118). The authors employed the Mn-tmtacn complex (Mn/168a) in the presence of sodium ascorbate as very efficient cocatalyst and 30% H2O2 as oxidant to oxidize 1-butanol to butyric acid and 2-pentanol to 2-pentanone in yields of 90% and 97%, respectively. This catalytic system shows very good catalytic activity, as can be seen from the fact that for the oxidation of 2-pentanol as little as 0.03% of the catalyst is necessary to obtain the ketone in excellent yield. 

Given this restriction, an area of uncertainty still remains. In case of the reaction of (Z)-2-butene with diisopinocampheylborane (l)6, it appears sensible to proceed as follows. If the primary diastereoisomeric boranes 2a, b are characterized, either by isolation or spectroscopy, the reaction can be classed as distereoselective but if, without characterization, oxidation to 2-butanol is performed, the reaction has to be classed as enantioselective. 

Acute pyridine treatment (single intraperitoneal dose of 200 mg/kg bw) increased the metabolism of 2-butanol twofold in Sprague-Dawley rat liver microsomes and threefold in rabbit (New Zealand White) liver microsomes (Page Carlson, 1993). In liver microsomes from pyridine-treated (one intraperitoneal injection of 100 mg/kg bw, daily for four days) male Sprague-Dawley rats, increased oxidative biotransformation of the chlorofluorocarbon l,2-dichloro-l,l,2-trifluoroethane was found the day after the last injection (Dekant et al, 1995). 

This approach is used in the oxidation of 2-hexene-l-ol and 2-butanol in the presence of either yeast ADH (YADH) or ADH from T. brockii with in situ regeneration of NAD(P)+ by indirect electrolysis with tris(3,4,7,8-tetramethyl-1,10-phenanthroline) iron (II/III) complex at an anode potential of 630 mV vs NHE (Fig. 15) [91]. 

Fig. 15 Electrochemically driven oxidation of 2-hexen-l-ol and 2-butanol to 2-hexenal and 2-butanone, respectively, catalyzed by ADH from Thermoanaerobacter brockii. tmphen 3,4,7,8-tetramethy 1-1,10-phenanthroline...

Titanium-pillared montmorillonites (Ti-PILC) modified with tartrates were described as heterogeneous Sharpless epoxidation catalysts [33] as well as for the oxidation of aromatic sulfides [34]. Metal oxides modified with histamine showed modest efficiencies for the kinetic resolution of activated amino acid esters (kj /k5 2) [35]. Silica or alumina treated with diethylaluminium chloride and menthol catalyzed the Diels-Alder reaction between cylopentadiene and methacrolein with modest enantioselectivities of up to 31% ee [36]. ZeoHte HY, modified with chiral sulfoxides had remarkable selectivities for the kinetic resolution of 2-butanol (k /kj =39) but unfortunately the catalyst is not very stable... 

The values of G for methanol and other primary alcohols are listed in Tables 2 and 3. Radiation-induced oxidation of rc-butanol was studied by Komarov et al. [66,67] over a wide temperature range. 

Yield of 2-butanol and reaction selectivity over various oxide catalysts... 

Kus, S Taniewski, M. The effect of some impurities on the basicity of MgO tested by the transformation of 2-butanol and on its catalytic performance in oxidative coupling of methane. Fuel Processing Technology, 2002 76, 41-49. 

Lopez, T Gomez. R Llanos. ME Lopez-Salinas, E. Acidic-base properties of silica-magnesia sol-gel mixed oxides use of 2-butanol as test reaction. Materials Letters, 1999 38, 283-288. 

Dichloro-7-methoxy acridine may be prepared by the oxidation of 2,4-dichloro toluene and treating the resulting acid with 4-amino anisole at 220°C in the presence of KOH and w-butanol the additional compound when reaeted with either POCI3 or SOCI2 undergoes cyclization. One mole each of the side chain and the acridine residue get eondensed to yield the mepacrine base which on treatment with hydrochloric acid gives the offieial eompound. 

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