Methanol hydrogenation, selectivity

Ergosterol (a triene) rapidly takes up 1 mole of hydrogen selectively to give 5a,6-dihydroergosterol, recrystallized from methanol-chloroform, mp 173-174°. 

Figure 2.16 Methanol conversion as a function of temperature hydrogen selectivity vs. methanol conversion for autothermal methanol reforming [39] (by courtesy of ACS).

The production of methanol via selective fermentation or direct hydrogenation of carbon monoxide. 

Degradation of dihydrostreptomycin in methanolic hydrogen chloride yielded methyl dihydrostreptobiosaminide, which formed a pentaacetyl derivative on acetylation. - - - Both anomers of this compound were isolated.The crystalline methyl pentaacetyldihydrostreptobio-saminfde was also obtained by selective hydrolysis of the non-glycosidic acetal group in methyl streptobiosaminide dimethyl acetal followed by catalytic hydrogenation and acetylation. 

In the presence of a BINAP-Ru complex (Structures 10 and 11), geraniol (7) or nerol (9) is hydrogenated selectively at the C(2)-C(3) double bond to give citronellol (8) quantitatively (Scheme 2) [19]. This hydrogenation is effected in methanol with a substrate catalyst ratio as high as 50000 1 to give either natural or unnatural compounds in up to 99 % enantiomeric purity. 

Recently Brinkmann et al. [2.295] reported a theoretical and experimental study of the oxidative dehydrogenation of methanol to CO2 and H2 by using a CMR with a Pt impregnated tubular alumina membrane. The authors studied the influence on reactor performance of the transmembrane pressure or the purge stream to feed ratio. Conversion increased as either one of these increased, the reactor conversion reaching as high as 84 %, while the hydrogen selectivity remained near 50 %. 

Although the hydrogenation rate of 1,5-cyclooctadiene is lower in ethanol and 1-propanol than in methanol, the selectivity is the same [43]. The PVPD-Pd catalyst is insoluble in ethyl acetate and tetrahydrofuran and shows low activity. The rate of 1,3- and 1,5-cyclooctadiene hydrogenation is expressed by the following equation ... 

On the base of work by Gordy and Stanford, the spectroscopic criterion, related to the extent of the shift to lower frequencies of the OD infrared absorption of deuterated methanol, was selected. It provides a measure of the hydrogen-bonding acceptor power of a sol-vent. The spectrum of a deuterated methanol solution in the test solution was compared with that of a solution in benzene and the hydrogen-bonding parameter was defined as... 

In the case of the sintered mixture of dendritic copper and Cu/ZnO catalyst powder [35] forming the reactor walls, the final reactor design included vaporization, CAR of methanol and selective CO oxidation for CO reduction in the presence of hydrogen (Figure 25.6). For the vaporization and selective CO oxidation, the sintered metal was additionally coated with platinum. The outlet flow of the reactor consisted of 40% hydrogen, 20% CO2, 0.1% CO and residues of 1.2% methanol (dry basis, balance N2) at a steam to carbon ratio of 1. 

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