Chemistry: electrical and wave energy – Processes and products – Processes of treating materials by wave energy
Reexamination Certificate
1998-12-28
2001-04-03
Wong, Edna (Department: 1741)
Chemistry: electrical and wave energy
Processes and products
Processes of treating materials by wave energy
Reexamination Certificate
active
06210538
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for triggering and/or carrying out chemical reactions by irradiating starting materials and, in particular, liquid, or mixtures of liquid and solid, starting materials with short-wave electromagnetic radiation emitted from at least one substance sending out short-wave electromagnetic radiation upon irradiation and excitation with long-wave electromagnetic radiation under operating conditions, as well as a device for triggering and/or carrying out chemical reactions by irradiating with short-wave electromagnetic radiation starting materials and, in particular liquid, or liquid and solid, starting materials received in a receptacle, comprising a generator for generating long-wave electromagnetic radiation as well as a vessel for receiving at least one substance emitting short-wave electromagnetic radiation upon irradation and excitation with long-wave electromagnetic radiation under operating conditions.
2. Prior Art
The realization of chemical reactions or processes by irradiation has been known for long with the most diverse effects being obtainable as a function of the substances used and the radiations applied. In this context, it is known to initiate or promote chemical processes by irradiation with long-wave electromagnetic waves such as, for instance, microwaves or with short-wave electromagnetic waves such as ultraviolet waves. Thus, it is known that it is possible by means of ultraviolet radiation to kill germs in food and luxury food or in biologic materials, thereby sterilizing such materials without having to apply elevated temperatures. Moreover, it is feasible to start, or keep going, specific reactions by excitation with electromagnetic waves in the UV range, whereas the use of microwaves is of particular advantage in chemistry if reactions or processes are to occur at elevated temperatures.
In many cases, however, it is particularly the combination of both long-wave and short-wave electromagnetic waves which yields particularly rapid and good results such that EP-A 0 429 814 has already proposed both a process and a device for triggering and/or promoting chemical processes, in which both long-wave electromagnetic waves, namely microwaves, and short-wave electromagnetic waves, namely ultraviolet rays, have been employed. In that process and the pertinent arrangement, it is proceeded in a manner that a receptacle for the starting materials to be treated and a gas reaction tube are arranged in a microwave oven, wherein the waves emitted from the microwave oven impinge on the gas reaction tube containing substances capable of being excited by microwaves and sending out UV rays upon excitation. The UV rays sent out by that gas reaction tube subsequently are directed onto the reaction vessel contained in the gas reaction tube or surrounded by the same and containing the substances or starting materials to be reacted. That known configuration involves the drawback that, in particular, a large-volume gas reaction tube having large dimensions suitable for surrounding an accordingly large reaction vessel must be provided and that, in particular, no uniform radiation density can be readily safeguarded over the total volume of the reaction vessel and particularly in its center at an accordingly large dimension of the reaction vessel. Another disadvantage of a gas reaction tube enclosing the reaction vessel resides in that exclusively materials that are transparent to short-wave electromagnetic radiation can be used for the reaction vessel. This constitutes a considerable limitation to the use of, in particular, pressure reaction vessels.
SUMMARY OF THE INVENTION
The present invention aims at providing a process and a device, by which it is feasible to afford directly in the reaction mixture to be reacted, or in the starting materials, as high a density of short-wave UV radiation as possible in order to be able to provide both a specific excitation and an accordingly augmented yield of reaction products.
To solve this object, the process according to the invention, departing from the initially defined prior art, is essentially characterized in that the short-wave electromagnetic radiation is generated in a closed vessel arranged within the starting materials and containing a short-wave electromagnetic radiation emitting substance. By emitting short-wave electromagnetic waves in a closed vessel arranged within the starting materials and containing the UV radiation emitting substances, an intensified UV irradiation of the reaction mixture or starting materials is feasible, thereby both improving and augmenting the reaction yields of the reaction excited by the electromagnetic radiation and offering the opportunity to carry out by the process according to the invention reactions that can only be excited by electromagnetic radiation of a specific wavelength.
In a preferred manner, and in order to provide an electromagnetic radiation of a specific wavelength, the process according to the invention is carried out such that a low pressure or negative-pressure gas is used as the short-wave electromagnetic radiation emitting substance. In order to ensure the safe ignition of the short-wave electromagnetic wave emitting gas, the process according to the invention preferably is conducted in a manner that ignition of the low pressure gas is caused by effecting an additional irradiation and excitation of a solid electrode and, in particular, a metallic electrode in the vessel receiving the low pressure gas. By providing an electrode and, in particular, a metallic electrode in the vessel receiving the low pressure gas or gas under subatmospheric pressure, an ignition spark is formed on the solid and, in particular, metallic electrode by the long-wave electromagnetic radiation, which ignition spark will safely ignite the low pressure gas contained in the vessel such that short-wave electromagnetic radiation will be continuously provided by the gas discharge of the low pressure gas.
In a preferred manner, the process according to the invention is conducted such that noble gases, methane, CO
2
and, in particular, gases emitting carbon bands at 193 and 247 nm are used for the low pressure gas in order to generate the short-wave electromagnetic radiation. By using noble gases, such as argon, methane or CO
2
, as well as gases emitting carbon bands at 193 and 247 nm, a specific excitation of selected substances may be effected and a concerted reaction control may be ensured.
For as broad a scattering as possible, of the short-wave electromagnetic radiation to be emitted, the process according to the invention is further developed such that metals or metal-like substances which, under operating conditions, form volatile substances sending out short-wave electromagnetic radiation upon irradiation and excitation with long-wave electromagnetic radiation are used as the short-wave electromagnetic radiation emitting substance, wherein As, Bi, Cd, Cs, Ge, Hg, P, Pb, Rb, Sb, Se, Sn, Te, Tl or Zn, in particular, are used as metals or metal-like substances. By providing metals or metal-like substances which, under operating conditions, form volatile substances acting as a short-wave electromagnetic radiation emitting substance, it is feasible to send out the most diverse excitation energies and the most diverse wavelengths of short-wave electromagnetic radiation such that a plurality of chemical reactions may be carried out by the process according to the invention.
By said short-wave electromagnetic radiation emitting substances being contained in a vessel arranged within the reaction mixture, an intensive irradiation of the reaction mixture or starting materials is, moreover, safeguarded such that not only a plurality of reactions may be carried by the process according to the invention, but also elevated yields of reaction products may be guaranteed.
In order to be able to simultaneously emit a plurality of different wavelengths of short-wave electromagnetic radiations, the process according to the invent
Knapp Gunter
Platzer Bernhard
Zischka Michael
Jacobson Price Holman & Stern PLLC
Knapp Günter
Wong Edna
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