Illumination – Light fiber – rod – or pipe – With gas or liquid container
Reexamination Certificate
1999-12-06
2001-05-29
Husar, Stephen (Department: 2875)
Illumination
Light fiber, rod, or pipe
With gas or liquid container
C362S556000, C522S001000
Reexamination Certificate
active
06238078
ABSTRACT:
FIELD OF THE INVENTION
My present invention relates to a method of promoting or enhancing chemical reactions and to a reactor or apparatus for carrying out such light-promoted or light-enhanced reactions.
BACKGROUND OF THE INVENTION
The use of light to promote chemical reactions has long been known and, in the art of photochemistry, it is known to utilize actinic radiation, for example, to promote polymerization reactions. It is also known to utilize selected frequencies of light to induce chemical decompositions or chemical exchange, substitution or replacement reactions.
For the present application, terms such as “promotion,”“catalytic activation” and “enhancement” insofar as they are intended to connote the activation of a chemical species so as to induce, maintain or facilitate chemical reaction are intended to be equivalent and to signify that the reaction may be in part or entirely initiated by the photons of light energy which are supplied, that the photons maintain the reaction after it has been initiated by light catalysis or otherwise, or that the photons provide some other effect which allows a chemical reaction to proceed.
In the past, it has been recognized that many chemical reactions involve the specific “opening” of a given chemical bond in one or more molecules to allow the recombination of such molecules into new compounds. Often such reactions are facilitated by carrying out the reactions on catalytic substrates, typically transition metals or their oxides, and particularly metals of the platinum group. The intermediating action of these substrates is believed to provide the activation of target electron orbitals to allow the reactions, without the substrate actually participating in the reaction. Such catalytic reactions are often subject to poisoning by impurities in that the active sites on the substrate become permanently bonded to, or otherwise affected by the “poisoning” species. Optically enhanced chemical reactions can be considered to be reactions catalyzed via the intermediate activation of orbital electrons or the outright ionization of molecular species. While optical radiation for enhancing chemical reaction rates is not wide-spread in industry, one could classify many polymerization processes as optically enhanced catalytic processes. The use of light in the enhancement of chemical reactions is therefore well known.
One of the problems encountered in the application of light to the enhancement of chemical reactions is due to the fact that if the light source contains wavelengths that are indeed beneficial to a given reaction, it is because the light at these wavelengths is absorbed by the reactants by the interaction with orbital electrons, or by the ionization of the molecules, or by selective breaking of chemical bonds between radicals attached to various host compounds or polymer backbones. This limits the use of such optical activation type processes to relatively thin films, and it has not been possible, to date to carry out such optically activated chemical reactions or optically enhance catalytic reactions in the bulk.
OBJECTS OF THE INVENTION
It is, therefore, the principal object of the present invention to provide an improved method of optically enhancing chemical reactions.
Another object is to provide a reactor which is capable of enhancing chemical reactions.
Still another object of the invention is to overcome the drawbacks of earlier photochemical reaction systems and particularly their limitations to thin-film applications so as to be able to effect photocatalytically-promoted or enhanced reactions in the body of a reactant rather than exclusively in a thin film thereof.
Still another object of this invention is to overcome drawbacks of prior art reaction systems and methods.
SUMMARY OF THE INVENTION
I have now discovered that certain principles developed in my copending application Ser. No. 08/724,069 filed Sep. 30, 1996 and entitled, “High efficiency Compound Parabolic Concentrators and Optical Fiber Powered Spot Luminaire”, now U.S. Pat. No. 5,727,108, and in my recent U.S. Pat. No. 5,222,795 entitled, “Controlled Light Extraction from Light Guides and Fibers” can be used with considerable advantage in the promotion and enhancement of chemical reactions to overcome the drawbacks of prior art techniques. More particularly the method of the invention comprises the steps of:
(a) providing a body of at least one chemical reactant in a reaction vessel in contact with at least one light extractor having an emission surface elongated in at least one direction and capable of emitting light over a length of the light extractor;
(b) generating light at a location outside the vessel and including light of at least one light frequency capable of promoting a chemical reaction with the reactant; and
(c) modifying the generated light to deliver to the light extractor the light of the light frequency.
The apparatus can be a reactor for effecting a chemical reaction which comprises:
a vessel receiving a body of at least one chemical reactant;
at least one light extractor at the vessel having an emission surface elongated in at least one direction and capable of emitting light over a length of the light extractor, the body of the chemical reactant being in contact with the surface;
means outside the vessel for generating light and including light of at least one light frequency capable of promoting a chemical reaction with the reactant; and
means between the means for generating and the light extractor for modifying the generated light to deliver the light of the frequency to the light extractor.
According to the invention, the light extractors which are compatible with the reactants and from which light is extracted over a length thereof can have the configuration described in U.S. Pat. No. 5,222,795. The spacing of the light extractors is selected to optimize photon flux utilization and both the design of the light extractors and the frequency of the light emitted therefrom and the spacing are optimized based upon the absorption spectra of the reactants.
It should be mentioned that while in the prior art, some optically activated reactions have been taught, particularly the UV assisted polymerization of various polymers, these optically assisted reactions have been limited to relatively thin layers that can be easily penetrated by the activating radiation and at a great loss of light resources. The losses in light resources are due to the fact that it is extremely difficult to provide from a point light source a large area of constant light flux. Furthermore, because of the difficulties in delivering efficiently and in a controlled manner activating radiation resources to reactants, the art of optically controlling chemical reaction rates of reactants by tuning the activating radiation or light to excitation potentials of specific molecules involved or to specific chemical bonds of the reactants, has not been practiced to the best of our knowledge. Furthermore, using selective excitation of reacting species enable reactions heretofore difficult to carry out or completely inaccessible to the prior art, in essence providing means for catalytic reactions without the use of any catalytic substrate.
While in the preferred embodiment of the instant invention, an extraction fiber, or optical wave guide as described in U.S. Pat. No. 5,222,795 is employed, it should be clear that the use of other light extractors, while not as efficient, is feasible as well. Such other light extractors have been described by Mori (U.S. Pat. Nos. 4,460,940, 4,471,412 and 4,822,123) and Cheslak (U.S. Pat. No. 4,765,701).
According to a feature of the invention, when two chemical reactants are reacted in a chemical reaction permitted by light of the light frequency resulting from modification of the generated light, at least one and preferably both of the reactants are passed along the light emissive surface and hence along the light extractor or light extractors. The light from the light generator and the light modifier may be delivered to the light extractors at leas
Dubno Herbert
Gate Technologies International, Inc.
Husar Stephen
LandOfFree
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