阅读说明：本技术 八氟环丁烷的提纯方法 (Purification method of octafluorocyclobutane ) 是由 张红敏 潘海涛 尚杨 贾磊磊 孙猛 金向华 于 2021-09-06 设计创作，主要内容包括：本发明公开了一种八氟环丁烷的提纯方法,包括对八氟环丁烷原料气进行吸附、氧化、精馏,氧化为将经过吸附后的原料气再行通过氧化柱进行氧化,氧化柱包括负载有氧化剂的载体,载体形成有多孔结构,并且载体在原料气流动方向形成有供原料气流通的通路。本发明方案可以得到纯度大于99.999％的产品,具有安全性高、设备投入少、耗能少、成本低、工艺操作简单、产品纯度高等优点。(The invention discloses a method for purifying octafluorocyclobutane, which comprises the steps of adsorbing, oxidizing and rectifying octafluorocyclobutane raw material gas, oxidizing the adsorbed raw material gas into a raw material gas, and oxidizing the raw material gas by an oxidation column, wherein the oxidation column comprises a carrier loaded with an oxidant, the carrier is provided with a porous structure, and a passage for the raw material gas to flow is formed in the flowing direction of the raw material gas. The scheme of the invention can obtain the product with the purity of more than 99.999 percent, and has the advantages of high safety, less equipment investment, less energy consumption, low cost, simple process operation, high product purity and the like.)

1. A method for purifying octafluorocyclobutane comprises the steps of adsorbing and rectifying octafluorocyclobutane raw material gas, and is characterized by further comprising the step of oxidizing the raw material gas after adsorption, wherein the oxidation step comprises oxidizing the raw material gas after adsorption by passing the raw material gas through an oxidation column, the oxidation column comprises a carrier loaded with an oxidant, the oxidant is loaded on the surface of the carrier and obtained by spraying an aqueous solution, the carrier forms a porous structure, and a passage for the raw material gas to flow is formed in the flowing direction of the raw material gas, the carrier is pretreated, the pretreatment of the carrier is to place 4.5-5 kg of newly ground graphite micropowder with the particle size of 1-10 microns into a reactor, hydrofluoric acid, nitric acid and hydrochloric acid which are 2.0-2.5 wt% of the graphite, 0.2-0.32 wt% of the graphite, 0.20-0.24 wt% of the graphite micropowder and then to mix the mixture, add pure water with the volume of 5-10 and fully stir the mixture, and raising the temperature of the reactor to 86-90 ℃, reacting for 3-4 hours, stirring every 1 hour in the reaction process, stirring for 4-6 min each time, immersing the carrier in the reactor, pressurizing to 1-3MPa with carbon dioxide under the condition of heat preservation, infiltrating for 2-3 hours, and taking out and drying.

2. The process for purifying octafluorocyclobutane according to claim 1, wherein the oxidation conditions are: the temperature is 20-60 ℃, and the pressure is 0.05-0.3 MPa.

3. The method of purifying octafluorocyclobutane according to claim 1 or 2, wherein the oxidizing agent comprises potassium permanganate or potassium dichromate.

4. The process for purifying octafluorocyclobutane according to claim 3, wherein the oxidizing agent is supported on the surface of the porous structure of the carrier.

5. The method of purifying octafluorocyclobutane according to claim 3, wherein the depth of adhesion of the oxidizing agent to the surface of the support is not more than 0.8 mm.

6. The method of purifying octafluorocyclobutane according to claim 1, wherein the carrier is zeolite or porous alumina or porous magnesia or porous ceramic.

7. The process for purifying octafluorocyclobutane according to claim 1, wherein the specific surface area of the carrier is 1 to 5m²/g。

8. The method for purifying octafluorocyclobutane according to claim 1, wherein the carrier has a mesh form formed of a woven fabric.

9. The method of purifying octafluorocyclobutane according to claim 8, wherein the woven body has a porous structure having micropores at least on the surface thereof.

Technical Field

The invention relates to the technical field of gas in fluorine chemical industry and electronic industry, in particular to a method for purifying octafluorocyclobutane.

Background

Octafluorocyclobutane has stable properties, is non-toxic, has zero Ozone Depletion Potential (ODP), has good insulation properties, and the like, and is widely used in the technical fields of high-voltage insulation, cleaning and etching, plasma treatment, and the like in recent years. High purity octafluorocyclobutane (not less than 5N) is mainly used as etchant and cleaning agent for large scale integrated circuit, and even very small amount of impurities in the application of integrated circuit etchant may increase the defect rate of high density integrated circuit; with the trend of higher performance, smaller size, higher winding density and finer circuit patterns of electronic or electrical equipment, high-precision circuit patterns are obtained, and the requirement on purity of octafluorocyclobutane is higher and higher.

The prior purification method of octafluorocyclobutane mainly comprises rectification and adsorption. There are many kinds of impurities in octafluorocyclobutane, and impurities, isomers and the like having a boiling point close to or azeotropic with octafluorocyclobutane often exist, and it is difficult to remove the impurities by a rectification method; the molecular sieve, the active carbon and the carbon molecular sieve which are commonly used in the adsorption method have small adsorption capacity on some impurities in the octafluorocyclobutane, the purification requirement is difficult to achieve, and the fluorocarbon impurities in the octafluorocyclobutane are difficult to remove by rectification and adsorption, so that the product with the purity of 99.999 percent or more is obtained.

The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

Disclosure of Invention

The invention aims to provide a method for purifying octafluorocyclobutane, which is used for obtaining a product with the purity of more than 99.999 percent by adopting a method combining adsorption, oxidation and rectification and has the advantages of high safety, low equipment investment, low energy consumption, low cost, simple process operation, high product purity and the like.

In order to achieve the above object, an embodiment of the present invention provides a method for purifying octafluorocyclobutane, which includes adsorbing, oxidizing, rectifying, and oxidizing the octafluorocyclobutane raw material gas into a raw material gas after the adsorption, and passing the raw material gas through an oxidation column for oxidation, wherein the oxidation column includes a carrier loaded with an oxidant, the carrier is formed with a porous structure, and the carrier is formed with a passage for the raw material gas to flow through in the raw material gas flow direction. The flow direction here refers to the feasible flow path from an upstream point to a downstream point in the flow path.

In one or more embodiments of the invention, in order to enhance the oxidation activity in the oxidation process and fully exert the activity and efficiency of oxygen radicals, the carrier is fully activated and pretreated, wherein the pretreatment comprises the steps of putting 4.5-5 kg of newly ground graphite micropowder with the particle size of 1-10 microns into a reactor, sequentially adding hydrofluoric acid accounting for 2.0-2.5 wt% of graphite, 0.2-0.32% of nitric acid and 0.20-0.24% of hydrochloric acid, mixing, adding 5-10 volume times of pure water, fully stirring, raising the temperature of the reactor to 86-90 ℃, reacting for 3-4 hours, stirring once every 1 hour in the reaction process, stirring for 4-6 min each time, immersing the carrier in the reactor, pressurizing to 1-3MPa with carbon dioxide under the condition of heat preservation, infiltrating for 2-3 hours, and then taking out and drying. Here, the high dissociation "H" provided by the hydrochloric acid⁺"Environment, providing appropriate" H "for activation of the support⁺And in an acidic environment, hydrofluoric acid and nitric acid are used as media under proper concentration, and the carrier is activated under the form of low-concentration active slurry. Meanwhile, the hydrofluoric acid which is slightly existed also slightly corrodes the surface of the carrier, so that more active centers are further provided, and the graphite microstructure after activation and adsorption can also become a new central point.

In one or more embodiments of the invention, the conditions of the oxidation are: the temperature is 20-60 ℃, and the pressure is 0.05-0.3 MPa.

In one or more embodiments of the invention, the oxidizing agent comprises potassium permanganate or potassium dichromate.

In one or more embodiments of the invention, the oxidizing agent is supported on the surface of the porous structure of the support.

In one or more embodiments of the invention, the depth of attachment of the oxidizing agent to the surface of the support is no greater than 0.8 mm.

In one or more embodiments of the present invention, the loading amount of the oxidizing agent on the surface of the support is obtained by spraying an aqueous oxidizing agent solution. The concentration of the oxidant aqueous solution is 0.0001-0.0005 g/ml. When the device works, the volume ratio of the spraying amount of the oxidant aqueous solution to the air input amount of the raw material gas is 1 (5-10).

In one or more embodiments of the invention, the support is a zeolite or porous alumina or porous magnesia or porous ceramic.

In one or more embodiments of the invention, the support has a specific surface area of 1 to 5m²(ii) in terms of/g. The micropores formed by the traditional porous structure in the scheme are more present for providing active centers, the adsorption or airflow of the main oxidant is not needed, one or more active centers are formed at the edge positions of the micropores with probability, and higher activation energy is provided, so that the pretreatment process can realize the purpose.

In one or more embodiments of the invention, the carrier has a mesh morphology formed by a braid.

In one or more embodiments of the present invention, the woven body has a porous structure having micropores at least on the surface thereof.

Compared with the prior art, the method according to the embodiment of the invention adopts adsorption to remove most of components such as water, oxygen, carbon dioxide and the like;

the method adopts oxidation, and the oxidation basically and completely removes fluorocarbon olefin impurities which are difficult to remove in the octafluorocyclobutane, thereby greatly reducing the cold and heat of the subsequent rectification, and having less energy consumption and good economical efficiency;

the method removes light components with low boiling point and heavy components with high boiling point, especially fluorocarbon impurities, through two-stage rectification, improves the purity of the product, and obtains an octafluorocyclobutane product with the purity of more than 99.999 percent;

the method adopts a combined process method of adsorption-oxidation-rectification, removes fluorocarbon impurities which are difficult to remove and greatly reduces the cold quantity and heat quantity required in the purification process by selecting an adsorbent with high selectivity, an oxidant with proper oxidation capacity and optimal rectification parameters, and has the advantages of simple process operation, high yield, large production capacity, less equipment investment, simple structure, suitability for industrial production and purity of more than 99.999 percent.

Drawings

FIG. 1 is a flow diagram according to an embodiment of the present invention;

FIG. 2 is a schematic view of a partial form of a carrier according to an embodiment of the present invention;

FIG. 3 is an enlarged partial view of a carrier according to an embodiment of the present invention;

fig. 4 is a further enlarged partial view of a carrier according to an embodiment of the present invention.

Detailed Description

The following detailed description of the present invention is provided in conjunction with the accompanying drawings, but it should be understood that the scope of the present invention is not limited to the specific embodiments.

Throughout the specification and claims, unless explicitly stated otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element or component but not the exclusion of any other element or component.

As shown in fig. 1 to 4, a method for purifying octafluorocyclobutane according to a preferred embodiment of the present invention.

Example 1

The purification method of the octafluorocyclobutane comprises the steps of adsorbing, oxidizing, rectifying and oxidizing octafluorocyclobutane raw material gas, wherein the raw material gas after adsorption is oxidized by an oxidation column at the temperature of 20 ℃ and the pressure of 0.05MPa, the oxidation column comprises a carrier loaded with an oxidant, namely potassium permanganate, and the specific surface area of the carrier is 1m²A porous ceramic carrier, and the carrier is formed with a passage through which a raw material gas flows in a flow direction of the raw material gas. Wherein the loading of the oxidizing agent on the carrier is effected in the form of a spray of an oxidizing agent solution, oxygenThe concentration of the oxidant aqueous solution is 0.0001g/ml, and the volume ratio of the spraying amount of the oxidant aqueous solution to the air input amount of the raw material gas is 1: 5.

As shown in fig. 2 to 4, the carrier 01 has a mesh form formed by the braid 011 (the formed mesh 010 is a raw material gas flow path), and the braid has a porous structure having micropores at least on the surface. In this case, a small groove structure 012 as shown in fig. 3 may be distributed on the surface of the braid, and the depth of the groove structure 012 defines the depth of the oxidant, and the depth is 0.5 mm.

The sample obtained in this example was sampled 10ml intermittently for purity detection, and the samples were sampled 10 times continuously at 1 hour intervals, and the average value was taken to obtain a purified product with a purity of 99.999% or more.

Example 2

The purification method of the octafluorocyclobutane comprises the steps of adsorbing, oxidizing, rectifying and oxidizing octafluorocyclobutane raw material gas, wherein the raw material gas after adsorption is oxidized by an oxidation column at the temperature of 30 ℃ and the pressure of 0.1MPa, the oxidation column comprises a carrier loaded with an oxidant, namely potassium permanganate, and the specific surface area of the carrier is 2m²A zeolite per gram, and the carrier is formed with a passage in the flow direction of the raw material gas through which the raw material gas flows. Wherein the loading of the oxidant on the carrier is realized in the form of oxidant solution spraying, the concentration of the oxidant aqueous solution is 0.0002g/ml, and the volume ratio of the spraying amount of the oxidant aqueous solution to the air input amount of the raw material gas is 1: 6.

The sample obtained in this example was sampled 10ml intermittently for purity detection, and the samples were sampled 10 times continuously at 1 hour intervals, and the average value was taken to obtain a purified product with a purity of 99.999% or more.

Example 3

The purification method of the octafluorocyclobutane comprises the steps of adsorbing, oxidizing, rectifying and oxidizing octafluorocyclobutane raw material gas, wherein the raw material gas after adsorption is oxidized by an oxidation column at the temperature of 40 ℃ and the pressure of 0.15MPa, the oxidation column comprises a carrier loaded with an oxidant, namely potassium permanganate, and the specific surface area of the carrier is 3m²A porous alumina in a volume of one gram and a support formed with a feed material in the direction of feed gas flowA path for the circulation of air. Wherein the loading of the oxidant on the carrier is realized in the form of oxidant solution spraying, the concentration of the oxidant aqueous solution is 0.0003g/ml, and the volume ratio of the spraying amount of the oxidant aqueous solution to the air input amount of the raw material gas is 1: 7.

As shown in fig. 2 to 4, the carrier 01 has a mesh form formed by the braid 011 (the formed mesh 010 is a raw material gas flow path), and the braid has a porous structure having micropores at least on the surface. In this case, as shown in fig. 4, the surface of the knitted fabric may be provided with small protrusions 014 and gaps 013 spaced from each other, and the difference in height between the small protrusions 014 and the gaps 013 defines the depth of adhesion of the oxidizing agent, and the difference in height between the small protrusions 014 and the gaps 013 is 0.8 mm.

The sample obtained in this example was sampled 10ml intermittently for purity detection, and the samples were sampled 10 times continuously at 1 hour intervals, and the average value was taken to obtain a purified product with a purity of 99.999% or more.

Example 4

The purification method of the octafluorocyclobutane comprises the steps of adsorbing, oxidizing, rectifying and oxidizing octafluorocyclobutane raw material gas, wherein the raw material gas after adsorption is oxidized by an oxidation column at the temperature of 50 ℃ and the pressure of 0.2MPa, the oxidation column comprises a carrier loaded with an oxidant potassium dichromate, and the specific surface area of the carrier is 4m²A porous magnesia in a volume of one gram per gram, and the carrier is formed with passages in the flow direction of the raw material gas through which the raw material gas flows. Wherein the loading of the oxidant on the carrier is realized in the form of oxidant solution spraying, the concentration of the oxidant aqueous solution is 0.0004g/ml, and the volume ratio of the spraying amount of the oxidant aqueous solution to the air input amount of the raw material gas is 1: 9.

The carrier is formed by stacking particles with the particle size of 3-5 mm.

The sample obtained in this example was sampled 10ml intermittently for purity detection, and the samples were sampled 10 times continuously at 1 hour intervals, and the average value was taken to obtain a purified product with a purity of 99.999% or more.

Example 5

The purification method of octafluorocyclobutane comprises the steps of adsorbing, oxidizing, rectifying and oxidizing octafluorocyclobutane raw material gas into the raw material gas after adsorptionThen passing through an oxidation column at 60 deg.C and 0.3MPa, wherein the oxidation column comprises a carrier loaded with potassium dichromate as oxidant and has a specific surface area of 5m²A porous ceramic carrier, and the carrier is formed with a passage through which a raw material gas flows in a flow direction of the raw material gas. Wherein the loading of the oxidant on the carrier is realized in the form of oxidant solution spraying, the concentration of the oxidant aqueous solution is 0.0005g/ml, and the volume ratio of the spraying amount of the oxidant aqueous solution to the air input amount of the raw material gas is 1: 10.

The carrier is formed by stacking columns of 3-5 cm.

The sample obtained in this example was sampled 10ml intermittently for purity detection, and the samples were sampled 10 times continuously at 1 hour intervals, and the average value was taken to obtain a purified product with a purity of 99.999% or more.

Example 6

The purification method of the octafluorocyclobutane comprises the steps of adsorbing, oxidizing, rectifying and oxidizing octafluorocyclobutane raw material gas, wherein the raw material gas after adsorption is oxidized by an oxidation column at the temperature of 20 ℃ and the pressure of 0.05MPa, the oxidation column comprises a carrier loaded with an oxidant, namely potassium permanganate, and the specific surface area of the carrier is 1m²A porous ceramic carrier, and the carrier is formed with a passage through which a raw material gas flows in a flow direction of the raw material gas. Wherein the loading of the oxidant on the carrier is realized in the form of oxidant solution spraying, the concentration of the oxidant aqueous solution is 0.0001g/ml, and the volume ratio of the spraying amount of the oxidant aqueous solution to the air input amount of the raw material gas is 1: 5.

As shown in fig. 2 to 4, the carrier 01 has a mesh form formed by the braid 011 (the formed mesh 010 is a raw material gas flow path), and the braid has a porous structure having micropores at least on the surface. In this case, a small groove structure 012 as shown in fig. 3 may be distributed on the surface of the braid, and the depth of the groove structure 012 defines the depth of the oxidant, and the depth is 0.5mm, and is pre-treated.

The pretreatment of the carrier can be to take 4.5kg of newly ground graphite micro powder with the particle size of 10 microns and put into a reactor, sequentially add hydrofluoric acid, nitric acid and hydrochloric acid which account for 2.0 percent, 0.3 percent and 0.20 percent of the weight percent of the graphite, then mix and add pure water with the volume of 8 times of the volume of the mixture and fully stir, then raise the temperature of the reactor to 86 ℃ and react for 4 hours, stir every 1 hour in the reaction process, stir for 4 minutes every time, then immerse the carrier in the reactor, pressurize to 3MPa under the heat preservation condition and soak for 2 hours, and then take out and dry.

The sample obtained in this example is subjected to intermittent sampling for 10ml to detect the purity, the sampling is continuously performed for 10 times at intervals of 1 hour, and the product with the purity of more than 99.99999% after purification is obtained by taking the average value.

Example 7

The purification method of the octafluorocyclobutane comprises the steps of adsorbing, oxidizing, rectifying and oxidizing octafluorocyclobutane raw material gas, wherein the raw material gas after adsorption is oxidized by an oxidation column at the temperature of 30 ℃ and the pressure of 0.1MPa, the oxidation column comprises a carrier loaded with an oxidant, namely potassium permanganate, and the specific surface area of the carrier is 2m²A zeolite per gram, and the carrier is formed with a passage in the flow direction of the raw material gas through which the raw material gas flows. Wherein the loading of the oxidant on the carrier is realized in the form of oxidant solution spraying, the concentration of the oxidant aqueous solution is 0.0002g/ml, and the volume ratio of the spraying amount of the oxidant aqueous solution to the air input amount of the raw material gas is 1: 6.

The pretreatment of the carrier can be to take 5kg of newly ground graphite micro powder with the particle size of 1 micron to be placed into a reactor, sequentially add hydrofluoric acid, nitric acid and hydrochloric acid which account for 2.5 percent, 0.32 percent and 0.22 percent of the weight percent of the graphite, mix and then add pure water with the volume 10 times of the volume of the mixture to be fully stirred, then raise the temperature of the reactor to 88 ℃ to react for 3.4 hours, stir every 1 hour in the reaction process, stir for 5min every time, then immerse the carrier in the reactor, pressurize to 2MPa under the heat preservation condition to soak for 3 hours, and then take out and dry.

The sample obtained in this example was sampled 10ml intermittently for purity detection, and the samples were sampled 10 times continuously at 1 hour intervals, and the average value was taken to obtain a product with a purity of 99.99996% or higher after purification.

Example 8

The purification method of octafluorocyclobutaneComprises the steps of adsorbing, oxidizing and rectifying octafluorocyclobutane raw material gas, oxidizing the adsorbed raw material gas by an oxidation column at the temperature of 0 ℃ and the pressure of 0.15MPa, wherein the oxidation column comprises a carrier loaded with an oxidant potassium permanganate and has the specific surface area of 3m²The porous alumina, and the carrier is provided with a passage for the raw material gas to flow through in the flowing direction of the raw material gas. Wherein the loading of the oxidant on the carrier is realized in the form of oxidant solution spraying, the concentration of the oxidant aqueous solution is 0.0003/ml, and the volume ratio of the spraying amount of the oxidant aqueous solution to the air input amount of the raw material gas is 1: 7.

As shown in fig. 2 to 4, the carrier 01 has a mesh form formed by the braid 011 (the formed mesh 010 is a raw material gas flow path), and the braid has a porous structure having micropores at least on the surface. In this case, as shown in fig. 4, a structure in which the small protrusions 014 and the gaps 013 are spaced apart from each other may be distributed on the surface of the braid, and the difference in height between the small protrusions 014 and the gaps 013, which defines the depth of adhesion of the oxidizing agent, is 0.8mm, and is pre-treated.

The pretreatment of the carrier can be to take 4.75kg of newly ground graphite micro powder with the particle size of 5 microns and put into a reactor, sequentially add hydrofluoric acid, nitric acid and hydrochloric acid which account for 2.25 percent, 0.2 percent and 0.24 percent of the weight percent of the graphite, then mix and add pure water with 5 volume times of the volume of the mixture and fully stir, then raise the temperature of the reactor to 90 ℃ and react for 3 hours, stir every 1 hour in the reaction process, stir for 6 minutes every time, then immerse the carrier in the reactor, pressurize to 1MPa under the heat preservation condition and soak for 2.5 hours by carbon dioxide, and then take out and dry.

The sample obtained in this example is subjected to intermittent sampling for 10ml to detect the purity, the sampling is continuously performed for 10 times at intervals of 1 hour, and the product with the purity of more than 99.99999% after purification is obtained by taking the average value.

In operation, in addition to the oxidation process, other modifications may be made as is conventional in the art, including but not limited to the following: as shown in fig. 1, a raw material crude product octafluorocyclobutane (raw material gas) enters an adsorption column (an adsorbent is one or a combination of more than one of molecular sieve, activated carbon, silica gel and alumina) in a gas form through a heat exchanger, the temperature is 20-60 ℃, the pressure is 0.05-0.3MPa, most of components such as water, oxygen, carbon dioxide and the like are removed by adsorption, the raw material crude product octafluorocyclobutane is directly discharged into the oxidation column (an oxidant is potassium permanganate, a carrier is porous alumina) after gas phase adsorption, the temperature is 20-60 ℃, the pressure is 0.05-0.3MPa, olefin impurities in fluorocarbon impurities are removed by oxidation, the oxidized octafluorocyclobutane gas enters a rectifying tower, namely a light-removing tower T01 for light-removing treatment, the bottom temperature is 15-50 ℃, the pressure is 0.1-0.6 MPa, the top temperature is 10-45 ℃ lower than the bottom, the pressure is 0.08-0.6 MPa, low-boiling point substances discharged from the top of the tower directly enter a low-boiling point impurity tank, the tower bottom material enters a de-weighting tower T02 for de-weighting treatment; the temperature of the bottom of the de-heavy tower T02 is 5-45 ℃, the pressure is 0.08-0.5 MPa, the temperature of the top is 0-40 ℃ lower than that of the bottom, the pressure is 0.05-0.45 MPa, high boiling point substances discharged from the bottom of the tower directly enter a high boiling point impurity tank, and the product with the purity of more than 99.999 percent is obtained after the tower top is rectified.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. It is not intended to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and its practical application to enable one skilled in the art to make and use various exemplary embodiments of the invention and various alternatives and modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims and their equivalents.