Adam catalyst platinum

N-Methyl-2,3-dimethoxybenzylamine has been prepared by the reaction of 2,3-dimethoxybenzyl chloride with methylamine and by the catalytic reduction of a mixture of 2,3-dimethoxybenzal-dehyde and methylamine using Adams platinum catalyst. ... 

The metal-catalysed hydrogenation of the higher olefins exhibit general features which are similar to those observed with the n-butenes. Thus, for example, the hydrogenation of hex-1-ene over Adams platinum catalyst [144] is accompanied by very low amounts of double-bond migration the relative rates of isomerisation and hydrogenation are in the ratio 0.03 1. Similarly, in the liquid phase hydrogenation of the n-pentenes over platinum—charcoal and iridium—charcoal [145], little or no isomerisation... 

A mixture of 48 g (0.167 mole) of a,a-diphenyl-2-pyridinemethanol hydrochloride (Emraert et al., Ber. 72B, 1188 (1939) 74B, 714 (1940), 160 ml of ethanol, and 3 0.5 g of Adams platinum catalyst was shaken under an initial hydrogen pressure of 60 pounds. The theoretical amount of hydrogen was absorbed in 5 hours. The reaction mixture was refluxed, diluted with enough water to dissolve all the white solid, and filtered hot from the catalyst. The filtrate was cooled and filtered yield of 38 g of a,a-diphenyl-alpha-(2-piperidyl)methanol white product melting at 308-309°C with decomposition. 

Oxidations of hexofuranose derivatives have been performed over Adams platinum catalyst, and a protective effect of a primary p-tolylsulfonyloxy group against oxidation at an adjacent C-5 hydroxyl group has been demonstrated. 3-Deoxy-l,2-0-isopropylidene-6-0-p-... 

The Exchange of Deuterium with Methanol over Adams Platinum Catalyst and the Effect of Certain Nitro Compounds Upon the Rate of This Exchange... 

Deuterium gas exchanges rapidly with methanol over Adams platinum catalyst at 35 . The influence of catalyst weight and treatment and of deuterium pressure on this exchange have been studied, as well as the effects of several aromatic, aliphatic, and olefinic nitro and related compounds. All of these nitro compounds reduce the rate of the exchange reaction initially, and the magnitude of such reduction increases with increasing specific rate constant for the platinum catalyzed hydrogenation of these compounds. 

Although the exchange of the hydroxyl hydrogen in methanol with deuterium in various deuterium compounds such as deuterium oxide and deuterium sulfide has been reported 1-3) and the preparation of methanol-d (CH3OD) by the saponification of esters and decomposition of Grignard reagent with deuterium oxide has been described 4 6), the catalytic exchange of deuterium gas with methanol over Adams platinum catalyst has not been previously studied. 

The exchange of deuterium gas with acetic acid over Adams platinum catalyst and the effect of nitro compounds 7,8) on this exchange have been investigated and the effects of these nitro compounds on the exchange correlated with their respective hydrogenation kinetics (5). An extension of exchange studies to methanol and deuterium gas over Adams platinum catalyst was undertaken. 

Data on the exchange over Adams platinum catalyst are shown in Table I. It is seen that increasing the weight of catalyst above 2 mg. did not increase the rate of exchange. The rate of shaking of the reaction vessel in the range 300-500 c.p.m. appears to have no effect on the exchange. 

Table II shows the effect of catalyst weight upon the rate of exchange of deuterium with methanol over prereduced and washed Adams platinum catalyst. The rate of exchange at both 300 and 500 c.p.m. shaker rate is the same. Three washes of the pre-reduced catalyst with purified methanol gave...

On the basis of these data, 2.0 mg. of Adams platinum catalyst which had been pre-reduced and washed three times was adopted as the standard for the runs involving the nitro compounds. 

The Effect of Catalyst Weight upon the Rate of Exchange of Deuterium with Methanol over Pre-reduced and Washed Adams Platinum Catalyst... 

Reducing and washing the Adams platinum catalyst removes a basic sodium residue which is associated with a strong proton acceptor 11). This residue arises from thermal decomposition of the sodium nitrate melt in the preparation of the catalyst. In solvents which are acidic, such as acetic acid, the basic residue does not reduce the catalytic activity, but in neutral solvents, such as methanol, it must be removed to obtain a satisfactory catalyst. 

Methanol over. 0 mg. of Adams Platinum Catalyst, Pre-reduced and Washed ... 

Fig. 1. The effect of various nitro compounds upon the rate of exchange of deuterium with methanol over 2.0 mg. of Adams platinum catalyst, pre-reduced and washed. A, methyl ethyl ketoxime B, nitroethane C, nitromesitylene D, aniline E, befa-nitrostyrene F, nitrobenzene G, 2-nitro-l-butene.

In any of these systems, the methanol exchange and reduction of the nitro or unsaturated compound, as evidenced by absorption of deuterium, are competitive reactions. The kinetics of hydrogenation of these nitro compounds in ethanol over Adams platinum catalyst are similar, being zero order in acceptor and first order in hydrogen pressure (IS). The aromatic and conjugated olefinic nitro compounds have much higher specific rate... 

The results on the exchange reactions indicate a similar order of attraction for the catalyst surface in methanol over prereduced and washed Adams platinum catalyst ... 

The plateaus may be explained by sufficient adsorption of unreduced nitro compound or oxime at higher concentrations to displace the amine. In nitroethane and methyl ethyl ketoxime, the active hydrogen may exchange with deuterium. Nitroethane over Adams platinum catalyst in the absence of solvent, under conditions similar to these, showed 6 % exchange... 

Ignoring the secondary effect on the exchange reaction from products formed during the exchange, the faster the nitro compound hydrogenates, the more it decreases the rate of exchange. This parallels the results obtained earlier for the acetic acid-deuterium exchange over Adams platinum catalyst. 

Hydroxypteridine monohydrate hydrogenated 20 min. with 10%-Pd-on-carbon in 0.1 N NaOH until Hg-absorption ceases -> 3,4-dihydro-2-hydroxypteridine. Y 67%.—2-Hydroxypteridine resists hydrogenation in neutral or acidic soln. with Raney-Ni or Adams platinum catalyst. The above example represents the first successful reduction of the pyrimidine ring in a pteridine. Also 7,8-dihydro-2-hydroxypteridine, by synthesis, s. A. Albert and S. Matsuura, Soc. 1961, 5131. 

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