Formic acid catalytic hydrogenation

PCSs obtained by dehydrochlorination of poly(2-dilorovinyl methyl ketones) catalyze the processes of oxidation and dehydrogenation of alcohols, and the toluene oxidation207. The products of the thermal transformation of PAN are also catalysts for the decomposition of nitrous oxide, for the dehydrogenation of alcohols and cyclohexene274, and for the cis-tnms isomerization of olefins275. Catalytic activity in the decomposition reactions of hydrazine, formic acid, and hydrogen peroxide is also manifested by the products of FVC dehydrochlorination... 

Gordon used a household microwave oven for the transfer hydrogenation of benz-aldehyde with (carbonyl)-chlorohydridotris-(triphenylphosphine)ruthenium(II) as catalyst and formic acid as hydrogen donor (Eq. 11.43) [61]. An improvement in the average catalytic activity from 280 to 6700 turnovers h-1 was achieved when the traditional reflux conditions were replaced by microwave heating. 

Uses and Reactions. Dihydromyrcene is used primarily for manufacture of dihydromyrcenol (25), but there are no known uses for the pseudocitronellene. Dihydromyrcene can be catalytically hydrated to dihydromyrcenol by a variety of methods (103). Reaction takes place at the more reactive tri-substituted double bond. Reaction of dihydromyrcene with formic acid gives a mixture of the alcohol and the formate ester and hydrolysis of the mixture with base yields dihydromyrcenol (104). The mixture of the alcohol and its formate ester is also a commercially available product known as Dimyrcetol. Sulfuric acid is reported to have advantages over formic acid and hydrogen chloride in that it is less complicated and gives a higher yield of dihydromyrcenol (105). 

Jessop and co-workers have pointed out that homogeneous catalysis in supercritical fluids can offer high rates, improved selectivity, and elimination of mass-transfer problems.169 They have used a ruthenium phosphine catalyst to reduce supercritical carbon dioxide to formic acid using hydrogen.170 The reaction might be used to recycle waste carbon dioxide from combustion. It also avoids the use of poisonous carbon monoxide to make formic acid and its derivatives. There is no need for the usual solvent for such a reaction, because the excess carbon dioxide is the solvent. If the reaction is run in the presence of dimethy-lamine, dimethylformamide is obtained with 100% selectivity at 92-94% conversion.171 In this example, the ruthenium phosphine catalyst was supported on silica. Asymmetric catalytic hydrogenation of dehydroaminoacid derivatives (8.16) can be performed in carbon dioxide using ruthenium chiral phosphine catalysts.172... 

The catalytic activity of certain polymers derived from 5,5 -methylenebis-(salicylaldehyde) for the decomposition of hydrazine (II, 41), isopropanol (//), formic acid (11), hydrogen peroxide (42), and the oxidation of cumene to its hydroperoxide (40) has been studied. 

The catalytic activity of some of these polymers for the decomposition of hydrazine (19, 59), isopropanol (19), formic acid (19), hydrogen peroxide (60) and for the oxidation of cumene to its hydroperoxide has been studied (55). 2,5-Dihydroxybenzoquinone selectively precipitates thorium and zirconium in the presence of other rare earths (55). Analysis of beryllium by spectro-photometric studies of its complexes with naphthazarin and/or alkannin has been developed into a rapid, sensitive, and accurate method (134). The synthesis of many of the polymers in Table IX.2 (pp. 274-279) for use as dyes was performed in 1912 (48). 

Hydrogen can be generated from formic acid-amine adducts at room temperature, and used directly in fuel cells [126,127]. Ruthenium metal carbonyl and hydrido carbonyl complexes exhibit a catalytic activity in the decarboxylation of formic acid. Hence, [Ru4(CO)i2H4] prepared from RUCI3 and formic acid can decompose formic acid to hydrogen and carbon dioxide [126]. 

Other potential processes for production of formic acid that have been patented but not yet commerciali2ed include Hquid-phase oxidation (31) of methanol to methyl formate, and hydrogenation of carbon dioxide (32). The catalytic dehydrogenation of methanol to methyl formate (33) has not yet been adapted for formic acid production. 

Oxidation. Maleic and fumaric acids are oxidized in aqueous solution by ozone [10028-15-6] (qv) (85). Products of the reaction include glyoxyhc acid [298-12-4], oxalic acid [144-62-7], and formic acid [64-18-6], Catalytic oxidation of aqueous maleic acid occurs with hydrogen peroxide [7722-84-1] in the presence of sodium tungstate(VI) [13472-45-2] (86) and sodium molybdate(VI) [7631-95-0] (87). Both catalyst systems avoid formation of tartaric acid [133-37-9] and produce i j -epoxysuccinic acid [16533-72-5] at pH values above 5. The reaction of maleic anhydride and hydrogen peroxide in an inert solvent (methylene chloride [75-09-2]) gives permaleic acid [4565-24-6], HOOC—CH=CH—CO H (88) which is useful in Baeyer-ViUiger reactions. Both maleate and fumarate [142-42-7] are hydroxylated to tartaric acid using an osmium tetroxide [20816-12-0]/io 2LX.e [15454-31 -6] catalyst system (89). 

The reduction of the double bond of an enamine is normally carried out either by catalytic hydrogenation (MS) or by reduction with formic acid (see Section V.H) or sodium borohydride 146,147), both of which involve initial protonation to form the iminium ion followed by hydride addition. Lithium aluminum hydride reduces iminium salts (see Chapter 5), but it does not react with free enamines except when unusual enamines are involved 148). 

As early as 1923 Hinshelwood and Topley (27) noted the exceptionally erratic behavior of palladium foil catalyst in the formic acid decomposition reaction within 140-200°C. The initially very high catalytic activity decreased 102 times during the exposure of palladium to hydrogen, which is a product of the reaction. Though the interpretation does not concern the /3-hydride formation, the authors observation deserves mentioning. 

Formic acid at 98% had to be used as a solvent during a catalytic hydrogenation by using the palladium/carbon system. When the solvent came into contact with the catalyst there was a release of hydrogen. Does this accident result from the acid decomposition catalysed by palladium In this case the decomposition... 

In addition to standard catalytic hydrogenolysis, methods for transfer hydrogenolysis using hydrogen donors such as ammonium formate or formic acid with Pd-C catalyst are available.216 The Cbz group also can be removed by a combination of a Lewis acid and a nucleophile for example, boron trifluoride in conjunction with dimethyl sulfide or ethyl sulfide.217... 

The synthesis of the /m-benzo-separated analogue 380 of the broad spectrum antibiotic fervenulin was reported (81JOC1699) in five steps from 7-chloro-2,4(l//,3//)quinazolinedione 374. Nitration of 374 gave 375, whose methylation gave 376. Pursuant to the synthesis of 380, 376 was converted into 377 with hydrazine and then formylated with formic acid to give 378 or converted to the ethoxymethylene derivative 379. Catalytic hydrogenation of 378 or preferably 379 gave 380. 

An interesting catalytic ruthenium system, Ru(7/5-C5Ar4OH)(CO)2H based on substituted cyclopentadienyl ligands was discovered by Shvo and coworkers [95— 98]. This operates in a similar fashion to the Noyori system of Scheme 3.12, but transfers hydride from the ruthenium and proton from the hydroxyl group on the ring in an outer-sphere hydrogenation mechanism. The source of hydrogen can be H2 or formic acid. Casey and coworkers have recently shown, on the basis of kinetic isotope effects, that the transfer of H+ and TT equivalents to the ketone for the Shvo system and the Noyori system (Scheme 3.12) is a concerted process [99, 100]. 

Other mechanisms for the synthesis of alkylformates, not via formic acid esterification, are possible. Hydrogenation of C02 to CO, followed by catalytic car-bonylation of alcohol, would produce alkyl formate. This mechanism seems more likely for the anionic metal carbonyls because they are known catalysts for alcohol carbonylation. However, Darensbourg and colleagues [64, 74, 85] showed... 

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