Device and method for producing high vacuum system with ultrawoman
(57) Abstract:The device includes a metal camera that can allocate gas on its surface, which comprises coating superimposed on at least the greater part of the surface of the metal wall that defines the chamber. The coating contains at least one layer constituting uncorrectable heteros, deposited on the surface of metal and the layer hetaera caused at least one thin layer of at least one catalyst selected from the group of ruthenium and/or rhodium and/or palladium, and/or osmium and/or iridium and/or platinum, and/or an alloy containing at least one of these metals. The method of obtaining high vacuum system with ultrawoman using the catalyst in the chamber defined by a metal wall, are known to produce gas on its surface: impose at least one thin layer is not evaporated hetaera on at least the greater part of the surface of the chamber wall, then put at least one thin layer of at least one catalyst for the specified layer hetaera, with the specified catalyst is chosen from the group of ruthenium and/or rhodium and/or palladium, and/iliut the chamber with the vacuum system and create a vacuum pumping system pumping. The use of this group of inventions can reduce the degree of degassing on the surface of the chamber walls and to increase the efficiency of pumping. 2 C. and 7 C.p. f-crystals. The present invention concerns improvements made to increase the vacuum in the system with ultrawoman, the construction of which provides for the presence of a camera, capable of degassing on its surface, consisting of coatings on at least the greatest part of the surface of the metal wall that defines the chamber.In a metal drainage system, which must be created ultraviscous [i.e., the vacuum is not less than 10-10Torr (10-8PA)] and even the order of 10-13-10-14Topp (10-11-10-12PA), the metal wall of the vacuum chamber is an inexhaustible source of gas. The hydrogen contained in the structural material (e.g. stainless steel, copper, aluminum alloys), is distributed freely on its thickness and weakens its distribution closer to the boundary surface consisting of a coating applied on at least the greatest part of the surface of the metal wall that defines the chamber. In addition, when the walls of wakeskates particles, there is a selection of even heavier molecules such as CO, CO2CH4formed on the surfaces of the walls after decomposition of hydrocarbons, carbides and oxides.Therefore, the depth of the vacuum obtained in the cell is determined by a dynamic equilibrium between the release of gases on the surface of the walls of the chamber and the pumping speed of the air used by the pumps. Getting high vacuum implies both a high surface purity of the camera, reducing the emission of gases and increased pumping speed. For vacuum systems, particle accelerators, which are usually small cross-section, the pumps should be located in close proximity to each other or must be provided by the constant pumping to overcome the limitations of conductivity.In these conditions, to obtain the highest possible vacuum it is necessary to increase the depth of the resulting vacuum, the obtained mechanical (pumps), using additional pumping, in particular, by using a hetaera, which is capable of producing chemically stable compounds, reacting with gases in the vacuum chamber (in particular with H2O2, CO, CO2, NLASS="ptx2">Therefore, regardless of the method of performing mechanical pumping and despite the effectiveness of separate pumping, allowing the use of Neispravan hetaera, the depth of the vacuum, which can be obtained in the chamber depends on the dynamic equilibrium between the pumping speed (regardless of the money involved and the degree of degassing of the metal surface of the camera (regardless of reason), in other words, at the present rate of pumping of the depth of the vacuum depends on the degree of degassing in the chamber.To increase the depth of ultracool in the chamber should, if possible, to reduce the degree of degassing on the metal surface of the camera and simultaneously increase the efficiency of pumping. As the closest analogue to the claimed group of inventions accepted source of information, known from the patent 03247776, With 23 28/00, 1991.Thus, the present of the invention is to reduce the degree of degassing on the surface of the chamber walls, as well as significantly increase the efficiency of money involved pumping, which would allow to obtain ultrahigh vacuum or ultracool [for example, of the order of 10-10-1013Topp (10-8-10-11notowanie device, to increase the depth of ultracool in a metal chamber that can reduce the release of gases on the surface of the camera and representing a coating on at least the greatest part of the metal surface that defines a chamber, according to the invention, the coating contains at least one layer Neispravan hetaera deposited on a metal surface of the chamber, and the layer is deposited, at least one thin layer, at least one catalyst selected from the group of ruthenium and/or rhodium and/or palladium, and /or osmium, and/or iridium and/or platinum, and/or an alloy containing at least one of the specified elements.In such a device the main advantage used in this invention catalysts is their low oxidation: when these catalysts are exposed to air, they almost do not interact with oxygen on its surface and therefore there is no need to stage activation by heating, which is intended to remove pestiviruses layer.There is also another advantage of using the proposed catalysts lies in their durability, as the absorption of gases the two is that slow degassing of the metal walls of the chamber and does not cause in turn, formation of gases. In addition, in the cells of particle accelerators this layer is exposed to caused by nearby particles, or the impact of synchrotron radiation, and which, forming screen, it prevents the release of molecules that can contaminate the vacuum in the chamber. Therefore, the catalyst bed is by preventing substantially degassing in the chamber, regardless of the cause.Finally, the above catalysts are able to create the effect of pumping at least some of the molecules on the surface of the camera.In this regard, the most interesting results were obtained with alloys based on palladium, in particular with an alloy of palladium-silver.Applying a layer of catalyst on the metal surface of the camera may be any known in the art and effective in this technical context, by the way, in particular by electrolytic deposition or by cathode sputtering, as will be set forth below.However, it should be noted that the catalyst has a number of disadvantages, one of which is that unlike Neispravan hetaera the catalyst of the example of H2and, but not always, such as, for example, N2and CO2. However, such selectivity in the most commonly encountered in practice applications (vacuum chamber of a particle accelerator) cannot be considered a disadvantage, because the molecules H2and are the majority.In addition, it should be noted that the catalysts have the effect of pumping hydrogen, which of course takes place, but which is limited at low pressure. However, lowering the temperature can increase the number of pumped hydrogen, with only one faction of the molecular layer at ambient temperature of about 20oWith; this number increases at lower temperatures. For example, when using palladium, which currently is the best catalyst, and this is confirmed by the results obtained at ambient temperature pressure equilibrium monolayer of hydrogen absorbed on the surface is 10-7Torr (10-5PA), and when the boiling point of liquid nitrogen (77 K), it can generally not be taken into account.It is to improve the pumping ability of the catalyst with respect to certain molecules, such as H2and e is the camera.Therefore, the above-mentioned molecules, such as, for example, hydrogen and its isotopes are transferred from the surface exposed to vacuum through the catalyst layer in the layer Neispravan hetaera or slowly at ambient temperature, or quickly, but when heated to about 50 to 70oC. Thus, if the ambient temperature of about 20oWith a layer of palladium saturated with hydrogen allows vacuum to a depth of 10-7Torr (10-5PA), then heated to a temperature of 70oWith the same catalyst allows to obtain a vacuum of the order of 10-13Torr (10-11PA). The total pumping is the volume of the layer Neispravan hetaera.As for the layer Neispravan hetaera, the selection of the components constituting the layer, and method of its application, it is possible to use any known in the art solution that can satisfy the requirements of the present invention. However, preference should be given to the technology described in the patent application France FR-a-2 750 248, filed on behalf of the present applicant, which discloses the technology in detail.It should be noted that neispravimyi eterny material (NGM) must, in particular, have a high absorption methods for the hydride phase; it should also be pressure dissociation (decomposition) hydride phase is less than 10-13Torr (10-11PA) at a temperature of about 20oC. Courtesans must have as well as can lower activation temperature that is compatible with temperatures dry vacuum systems (of the order of 400oWith cameras stainless steel, 200-250oWith cameras of copper and aluminum alloys), to be stable in contact with air at a temperature of about 20oC; under these conditions, typically the activation temperature should not exceed 400oWith and should not be below 150oC.In accordance with the present invention a thin layer Neispravan hetaera according to the invention is made of titanium and/or zirconium and/or hafnium and/or vanadium and/or scandium, the limit of solubility for oxygen at ambient temperature exceeds 2%, may represent a relevant neopreme hetaera for applying a thin layer in accordance with this invention. Of course you can use any alloy or compound of these metals, or any alloy or compound of one or more of these metals with other materials and thus to achieve the desired effect, and even for the following:
- to apply, at least one thin layer Neispravan hetaera on at least the greater part of the surface of the camera;
- then on the specified layer hetaera is applied, at least one thin layer of a catalyst selected from the group of ruthenium and/or rhodium and/or palladium, and/or osmium and/or iridium and/or platinum and/or alloy with at least one of these metals;
- the camera is connected with a vacuum system and creates a vacuum by pumping.The catalyst may be applied by cathode sputtering on a layer Neispravan hetaera, the layer Neispravan hetaera previously applied by cathodic sputtering without contact with the ambient atmosphere between the two applications.If preference is given to coating using the dual cathode sputtering, in the first stage, applying a layer of the above Neispravan hetaera is carried out using at least one first electrode adapted for cathode sputtering hetaera, as disclosed in the patent application France FR-A-2 750 248. Then after spraying the first electrode is removed from the camera and before you begin the second phase, replace sauvetage, when replacing the first electrode layer hetaera interacts with the environment, it is necessary before you can proceed to the application stage catalyst layer using cathode sputtering, to produce pumping, and then activated by heating the layer hetaera.An example of practical implementation of this method may consist of the following stages:
- clean the camera, set the device for applying a thin layer of a hetaera on the surface of the chamber walls; creating a relative vacuum in the chamber; dry the camera for maximum removal of her water vapor; a thin layer of hetaera on as a greater part of the surface of the chamber walls;
- create in the chamber to atmospheric pressure; remove from the camera device for applying a thin layer of a hetaera; set device for applying a catalyst on the surface of the chamber walls;
- create a relative vacuum in the chamber; dry installation at the required temperature, while the temperature in the chamber is kept lower than the activation temperature hetaera;
- finish the drying installation with simultaneous increase of the temperature in the chamber to the activation temperature hetaera, which is supported by the completion of this operation, the surface of a thin layer hetaera is clean and its thermal degassing significantly reduced;
- put at least one layer of the catalyst layer Neispravan hetaera.In order to avoid the negative consequences that arise when replacing electrodes (mainly the harmful effects of the environment on the layer hetaera), you can include the installation of double electrode, which contains two material (neispravimyi heteros and catalyst) and which is activated in such a way that are applied consistently first layer hetaera, then a layer of catalyst without intermediate processing of the hetaera. In order to achieve the deposition of a uniform layer over the entire surface of the camera can be applied to the rotating electrode.After the system generates the final vacuum the surface of the catalyst layer in the vacuum chamber is covered by several monolayers of water vapor, which then must be removed by pumping. Removal is much quicker, if simultaneously with the pumping carry out drying in the vacuum system, if possible, by heating at a temperature lying in the range from about 120 to about 300oC.The catalyst used in the above layer, is applied along the entire length of the surface of the camera and stores, sledovatel oedema the invention, practically does not change the volume of the chamber, which makes its use is preferred because it creates the effect of pumping even at zero volume of occupied space. This enables you to use it even in those cases where the geometrical laws do not allow the use of suction material in the form of a tape. 1. The device receiving the high vacuum system with ultrawoman containing metal camera that can allocate gas on its surface, which comprises coating superimposed on at least the greater part of the surface of the metal wall that defines the chamber, characterized in that the coating contains at least one layer constituting neispravimyi heteros, deposited on the surface of the specified metal walls defining the chamber, and on this layer hetaera caused at least one thin layer of at least one catalyst selected from the group of ruthenium and/or rhodium and/or palladium, and/or osmium and/or iridium and/or platinum, and/or an alloy containing at least one of these metals, so that its surface is almost not oxidized by contact with air, the layer of the catalyst is not filled with oxygen is existing in the chamber, some molecules, such as H2and its isotopes, move through this layer catalyst layer Neispravan hetaera, and the total amount of pumping is the volume of the pumping layer Neispravan hetaera.2. The device under item 1, characterized in that a thin layer of catalyst is a layer of an alloy of palladium.3. The device according to p. 2, characterized in that the catalyst is an alloy of palladium and silver.4. Device according to any one of paragraphs. 1-3, characterized in that the non vaporizing heteros is chosen from the group titanium and/or zirconium and/or hafnium and/or vanadium and/or scandium, or an alloy or compound containing at least one of these metals.5. Device according to one of paragraphs. 1-4, characterized in that the coating is heated to about 50 - 70oWith, so the exhaust gas is accelerated.6. A method of obtaining a high vacuum system with ultrawoman using the catalyst in the chamber defined by a metal wall, are known to produce gas on its surface, characterized in that impose at least one thin layer Neispravan hetaera on at least the greater part of the surface of the walls of the chamber, this specified catalyst is chosen from the group of ruthenium, and/or rhodium and/or palladium, and/or osmium and/or iridium and/or platinum, and/or an alloy containing at least one of these metals, connect the chamber with the vacuum system and create a vacuum pumping system pumping.7. The method according to p. 6, characterized in that the catalyst is applied by cathode sputtering on a layer Neispravan hetaera, who also previously applied by cathode sputtering, when heteros is not in contact with the surrounding atmosphere between the two applications.8. The method according to p. 6, characterized in that the layer Neispravan hetaera, deposited by cathodic sputtering and exposed to ambient air, pumped and activate by heating before application to him catalyst layer by cathodic sputtering.9. The method according to p. 6, characterized in that simultaneously with the creation of a vacuum pumping system pumping carry out drying in the vacuum system by means of its heating up to at least 120oC.
FIELD: industrial organic synthesis.
SUBSTANCE: invention provides catalyst for production of methyl ethyl ketone via oxidation of n-butenes by oxygen and/or oxygen-containing gas, which catalyst is composed of aqueous solution of molybdeno-vanado-phosphoric heteropolyacid or mixture of the latter with its salt and 5·10-4 to 1·10-2 M palladium stabilized by phthalocyanine ligand at palladium-to-phthalocyanine molar ratio 0.5-2. Mo-V-phosphoric heteropolyacid is depicted by formula H19P3Mo18V7O84. concentration of vanadium being 0.4 to 2.2 g-atom/L. Oxidation of n-butenes is carried out continuously in two steps at temperature 15 to 90оС. Catalyst is regenerated in contact with oxygen or oxygen-containing gas at 140-190оС and oxygen pressure 1-10 gauge atm.
EFFECT: enhanced process efficiency due to increased stability of catalyst components.
7 cl, 1 dwg, 6 tbl, 7 ex