Continuous process for the production of nano-scale metal particles

Abstract

A continuous process for producing nano-scale metal particles includes feeding at least one decomposable moiety selected from the group consisting of organometallic compounds, metal complexes, metal coordination compounds and mixtures thereof into a reactor vessel; exposing the decomposable moiety to a source of energy sufficient to decompose the moiety and produce nano-scale metal particles; and depositing or collecting the nano-scale metal particles.

Description

TECHNICAL FIELD [0001] The present invention relates to a continuous process for the production of nano-scale metal particles useful for catalysis and other applications. By the practice of the present invention, nano-scale metal particles can be produced and collected with greater speed, precision and flexibility than can be accomplished with conventional processing. Thus, the invention provides a practical and cost-effective method for preparing such nano-scale metal particles. BACKGROUND OF THE INVENTION [0002] Catalysts are becoming ubiquitous in modern chemical processing. Catalysts are used in the production of materials such as fuels, lubricants, refrigerants, polymers, drugs, etc., as well as playing a role in water and air pollution mediation processes. Indeed, catalysts have been ascribed as having a role in fully one third of the material gross national product of the United States, as discussed by Alexis T. Bell in “The Impact of Nanoscience on Heterogeneous Catalysis” (...

AI Technical Summary

Benefits of technology

[0018] The reactor vessel can be formed of any material which can withstand the conditions under which the decomposition of the moiety occurs. Generally, where the reactor vessel is a closed system, that is, where it is not an open ended vessel permitting reactants to flow into and out of the vessel, the vessel can be under subatmospheric pressure, by which is meant pressures as low as about 250 millimeters (mm). Indeed, the use of subatmospheric pressures, as low as about 1 mm of pressure, can accelerate decomposition of the decomposable moiety and provide smaller nano-scale particles. However, one advantage of the inventive process is the ability to produce nano-scale particles at generally atmospheric pressure, i.e., about 760 mm. Alternatively, there may be advantage in cycling the pressure, such as from sub-atmospheric to generally atmospheric or above, to encourage nano-deposits within the structure of the support. Of course, even in a so-called “closed system,” there needs to be a valve or like system for relieving pressure build-up caused, for instance, by the generation of carbon monoxide (CO) or other by-products. Accordingly, the use of the expression “closed system” is meant to distinguish the system from a flow-through type of system as discussed hereinbelow.

[0038] It is yet another object of the present invention to provide a continuous process for preparing nano-scale metal particles which can be collected for further use or treatment.

Problems solved by technology

One major drawback to the preparation of catalyst materials through loading on a carrier particle is in the amount of time the loading reactions take, which can be measured in hours in some cases.

Thus, these processes are difficult and expensive to operate and also operate in a line-of-sight manner, precluding full use of the support.

Even if technically feasible, however, the Bert and Bianchini methods require high temperatures (on the order of 300° C. to 800° C.)

, and require several hours. A

ccordingly, these processes are of limited value.

However, more significant uses of metal carbonyls are in the production and / or deposition of the metals present in the carbonyl, since metal carbonyls are generally viewed as easily decomposed and volatile resulting in deposition of the metal and carbon monoxide.

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