Platinum Metal Catalysts Research Articles

Carbon-supported platinum metal catalysts for hydrogenation reactions. Mass transport effects in liquid phase hydrogenation over Pd/C

Carbon-supported platinum metal catalysts for hydrogenation reactions. Mass transport effects in liquid phase hydrogenation over Pd/C

Carbon‐supported platinum metal catalysts for hydrogenation reactions. Mass transport effects in liquid phase hydrogenation over Pd/C

AbstractThe efficient use of palladium charcoal catalysts in liquid phase hydrogenation processes is shown to depend on hydrogen transport limitations from the bulk liquid phase to catalyst particles, and on the diffusion of hydrogen through the porous structure of the support to the active metal crystallites. These processes impose a strict limitation on the maximum rate of hydrogenation, and can effect the selectivity of reaction processes. The factors which control the output of a reactor in terms of operating conditions, and catalyst design are examined.

Hydrogenation and Hydrogenolysis. XIII. The Hydrogenation of Ethyl 4-Methyl-1-cyclohexenyl Ether over Platinum Metal Catalysts

Abstract The hydrogenation and hydrogenolysis of ethyl 4-methyl-1-cyclohexenyl ether (I) have been investigated with six unsupported platinum metals as catalysts at 25°C under atmospheric pressure of hydrogen. The hydrogenation of I in ethanol was accompanied by the formation of 4-methylcyclohexanone diethyl acetal (II), the extent of which depended on the nature of the catalyst metals. The ratio of the acetal formation to hydrogenation increased with respect to the catalyst metals in the sequence Os<Ru<Ir<<Rh<Pd<Pt. The amount of the hydrogenolysis to give methylcyclohexane increased in the order Pd≅Ru<<Os<Rh<Ir<<Pt at an initial stage of the hydrogenation in ethanol. This order in hydrogenolysis was explained in terms of the action of the ionized hydrogen on the catalyst surface and the olefin isomerization activity of the catalyst metals. The stereochemistry of the hydrogenation of I was also studied and the results were interpreted on the basis of the proposed mechanism. I was also hydro-genated in t-butyl alcohol and isopropyl ether as solvents and, except in a few cases, the proportion of hydrogenolysis decreased with solvent in the order ethanol>t-butyl alcohol>isopropyl ether. The stereoselectivity in ether formation did not differ much among the solvents except over palladium.

The Structure of Supported Platinum Catalysts

Modern techniques are steadily increasing our knowledge of the structure and properties of the supported platinum metal catalysts so widely used in chemical processing. The main function of the support, such as charcoal, alumina or silica, is to increase the surface area of the platinum metal and so to enhance catalyst performance, and methods for studying the dispersion of the platinum are therefore of considerable importance. This article describes the application of electron microscopy to the problem and compares the results given by this and other methods.

Reactions of cycloalkanones in the presence of platinum-metal catalysts and hydrogen

Reactions of cycloalkanones in the presence of platinum-metal catalysts and hydrogen

Hydrogenation and Hydrogenolysis. IX. The Hydrogenation of Benzyl Alcohol with Platinum Metal Catalysts

Abstract The rate of the hydrogenation of benzyl alcohol with a rhodium catalyst decreases markedly in the course of the reaction, accompanied by the formation of an increasing amount of cyclohexanecarboxaldehyde with the conversion of the alcohol. The decrease in the rate is only slight with a platinum catalyst, however, and the formation of the aldehyde is much less than with the rhodium catalyst. It has been shown that cyclohexanecarboxaldehyde is an effective catalyst poison in the hydrogenation of benzyl alcohol, but that cyclohexylcarbinol is not. 1-Cyclohexenylcarbinol, an intermediate of the hydrogenation, isomerizes to cyclohexanecarboxaldehyde during the hydrogenation on rhodium and 7 : 3 rhodium-platinum catalysts to a greater extent than on the platinum catalyst. Cyclohexanecarboxaldehyde is hydrogenated only very slowly, but the rate with the platinum catalyst is about four times greater than that with the rhodium catalyst. These results may account for the different behaviors of the rhodium or 7 : 3 rhodium-platinum catalyst and the platinum catalyst observed in the hydrogenation of benzyl alcohol.

Supported Platinum Metal Catalysts

Supported Platinum Metal Catalysts

Catalytic hydrogenation—I: The reaction of platinum metal salts with sodium borohydride—new active platinum metal catalysts for hydrogenation

The treatment of Pt metal salt solutions with sodium borohydride results in the formation of finely divided black precipitates. Certain of these precipitates ar active catalysts for the hydrolysis of sodium borohydride. SomePt, Pd and Rhare active catalysts for the hydrogenation of olefins. If the precipitation is carried out in the presence of high surface area supports such as activated carbon, these materials show even greater activity. The Pt catalyst is remarkably active as a catalyst for the hydrogenation of a large variety of olefins; Pd, on the other hand, shows a marked sensitivity toward olefin structure. Rates of reaction were followed in a novel way, using a standard solution of sodium borohydride added to acid to supply pure hydrogen as required to maintain the pressure.

Supported Platinum Metal Catalysts

Supported Platinum Metal Catalysts

Hydrogenation of Aniline to Cyclohexylamine with Platinum Metal Catalysts

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHydrogenation of Aniline to Cyclohexylamine with Platinum Metal CatalystsHarold GreenfieldCite this: J. Org. Chem. 1964, 29, 10, 3082–3084Publication Date (Print):October 1, 1964Publication History Published online1 May 2002Published inissue 1 October 1964https://doi.org/10.1021/jo01033a512RIGHTS & PERMISSIONSArticle Views488Altmetric-Citations53LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (400 KB) Get e-Alerts Get e-Alerts

Hydrogenation of Nitroaromatics in the Presence of the New Platinum Metal and Carbon-Supported Platinum Metal Catalysts

<b>Hydrogenation of Nitroaromatics in the Presence of the New Platinum Metal and Carbon-Supported Platinum Metal Catalysts</b>

A Simple Preparation of Highly Active Platinum Metal Catalysts for Catalytic Hydrogenation

<b>A Simple Preparation of Highly Active Platinum Metal Catalysts for Catalytic Hydrogenation</b>

Low Pressure Hydrogenation of Ketones with Platinum Metal Catalysts

Low Pressure Hydrogenation of Ketones with Platinum Metal Catalysts

584. Hydrogenation of oximes with platinum metal catalysts

584. Hydrogenation of oximes with platinum metal catalysts

The Manufacture of Hydrocyanic Acid by the Andrussow Process

The manufacture of hydrocyanic acid by the catalytic combination of methane, ammonia and air has increased remarkably in recent years. Some of the features of this process, particularly the variety of platinum metal catalysts employed in it, are surveyed in this article.

The platinum metal catalysts are now used for...

RETURN TO ISSUEPREVAdvertisementNEXTThe platinum metal catalysts are now used for...Cite this: Chem. Eng. News 1952, 30, 10, 971Publication Date (Print):March 10, 1952Publication History Published online5 November 2010Published inissue 10 March 1952https://doi.org/10.1021/cen-v030n010.p971Copyright © 1952 AMERICAN CHEMICAL SOCIETYArticle Views4Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (677 KB) SUBJECTS:Catalysts,Platinum,Metals Get e-Alerts