CN112920012A - Novel preparation method of electronic grade CHF3 - Google Patents
Novel preparation method of electronic grade CHF3 Download PDFInfo
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- CN112920012A CN112920012A CN202110126949.6A CN202110126949A CN112920012A CN 112920012 A CN112920012 A CN 112920012A CN 202110126949 A CN202110126949 A CN 202110126949A CN 112920012 A CN112920012 A CN 112920012A
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- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C17/00—Preparation of halogenated hydrocarbons
- C07C17/093—Preparation of halogenated hydrocarbons by replacement by halogens
- C07C17/20—Preparation of halogenated hydrocarbons by replacement by halogens of halogen atoms by other halogen atoms
- C07C17/202—Preparation of halogenated hydrocarbons by replacement by halogens of halogen atoms by other halogen atoms two or more compounds being involved in the reaction
- C07C17/206—Preparation of halogenated hydrocarbons by replacement by halogens of halogen atoms by other halogen atoms two or more compounds being involved in the reaction the other compound being HX
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- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
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- C07C17/38—Separation; Purification; Stabilisation; Use of additives
- C07C17/383—Separation; Purification; Stabilisation; Use of additives by distillation
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Abstract
The invention relates to the technical field of CHF3 preparation, in particular to a novel preparation method of electronic grade CHF3, which comprises preheating activation, catalytic synthesis, nitrogen temperature control and fractional rectification; the rectifying tower comprises a tower kettle, a reaction pipeline, a sealing diaphragm and a controller; because the boiling points of the compounds and the simple substances in the prepared trifluoromethane are relatively close to each other, the concentration of the trifluoromethane purified by rectification can hardly meet the requirement of electronic grade purity required by the semiconductor industry; therefore, the invention uses the reaction pipeline arranged in the rectifying tower and the fractionating conduit communicated and installed in the tower kettle, so that the trifluoromethane primary product prepared by the reaction pipeline after preheating and activation is directly and sequentially transmitted to the fractionating conduit under different temperature and pressure states through the fractionating conduit, and an adjustable independent cavity is formed in the tower kettle by using the sealing diaphragm and is adapted to the rectifying conditions required by the purification of the trifluoromethane under different purity states, thereby improving the operation effect of the novel preparation method of the electronic grade CHF 3.
Description
Technical Field
The invention relates to the technical field of CHF3 preparation, in particular to a novel preparation method of electronic grade CHF 3.
Background
The trifluoromethane CHF3 is a colorless, slightly odorous and non-conductive gas, wherein electronic-grade trifluoromethane is one of plasma etching gases widely applied in the microelectronic industry, particularly etching a silicon dioxide film, and has the advantages of high etching speed and good selectivity, the demand of the electronic-grade CHF3 is gradually increased along with the development of the semiconductor industry, the purity of the electronic-grade trifluoromethane is generally 99.9999%, and the electronic-grade CHF3 relates to a deep removal technology of various impurities.
At present, the prepared trifluoromethane contains a plurality of trace elements such as fluoride, simple substances and the like, and the impurities in the trifluoromethane are removed sequentially by adopting an intermittent rectification mode, wherein the boiling points of the compounds and the simple substances are relatively close to that of the trifluoromethane, so that the concentration of the rectified and purified trifluoromethane cannot meet the requirement of the electronic grade purity required by the semiconductor industry.
Some technical solutions related to the preparation method of electronic grade CHF3 also appear in the prior art, for example, a chinese patent with application number CN201410159290.4 discloses a trifluoromethane purification device and a purification method, the device includes a rectification device and an adsorption device connected with the rectification device, the rectification device includes a first-stage rectification device, a second-stage rectification device and a third-stage rectification device which are connected in sequence, the adsorption device includes a low-temperature adsorption device and a filling device which are connected in sequence, and the low-temperature adsorption device of the adsorption device is connected with the rectification device; compared with the prior art, the technical scheme has the advantages that the purity of the purified trifluoromethane is higher, the device is simple to operate, the purification process is complete and reliable, and the repeatability is strong. The removal of conventional impurities is considered, carbon dioxide, chlorodifluoromethane, pentafluoroethane, water and granularity which are difficult to remove are removed to a qualified range, the product purity is 99.999 percent, and the use requirement of the semiconductor industry is met; however, the technical scheme does not consider the similar boiling point parameters among all impurities in the purification process of the trifluoromethane, so that the effect of purifying the trifluoromethane is reduced.
In view of this, the present invention provides a novel method for preparing electronic grade CHF3, which solves the above technical problems.
Disclosure of Invention
In order to make up for the defects of the prior art, the invention provides a novel preparation method of electronic-grade CHF3, a trifluoromethane primary product prepared by preheating and activating a reaction pipeline is directly and sequentially transmitted to fractionation ducts under different temperature and pressure states through the fractionation duct arranged in a fractionation tower and a fractionation duct communicated and installed in a tower kettle, an adjustable independent cavity is formed in the tower kettle by utilizing a sealing diaphragm and is adapted to the fractionation conditions required by the purification of trifluoromethane under different purity states, and thus the operation effect of the novel preparation method of the electronic-grade CHF3 is improved.
The invention relates to a novel preparation method of electronic grade CHF3, which comprises the following steps:
s1, preheating and activating; introducing nitrogen into a reaction pipeline of the rectifying tower for circulating purging, heating the reaction pipeline to 180-fold-plus-210 ℃ for more than 30min, then introducing hydrogen fluoride gas into the circulating purged reaction pipeline for fluorination, controlling the amount of the supplemented hydrogen fluoride gas to account for 30-45% of the internal volume of the reaction pipeline, completing filling of the hydrogen fluoride gas within 7-11min, maintaining the temperature of the reaction pipeline at 175-fold-plus-205 ℃ for 20min, and completing activation of the reaction pipeline;
s2, catalytic synthesis: introducing monochlorodifluoromethane gas into the reaction pipeline of S1 to make the monochlorodifluoromethane gas occupy 25-35% of the volume of the reaction pipeline, synthesizing by matching with catalyst particles preset in the reaction pipeline, respectively heating the upper and lower sides of the reaction pipeline to make the temperature of the upper side of the reaction pipeline at 205-; by adding the insufficient amount of the chlorodifluoromethane gas, the hydrogen fluoride gas is prevented from being partially dissolved in the water formed by the reaction between the hydrogen fluoride gas and the chlorodifluoromethane gas to lose the activity of the hydrogen fluoride gas;
s3, controlling the temperature of nitrogen: after heating the upper side and the lower side of the reaction pipeline in S2, preparing a trifluoromethane initial product, continuously introducing nitrogen into the reaction pipeline, replacing the gas which does not participate in synthesis in the reaction pipeline, heating the reaction pipeline to 390 ℃ at 360-90 ℃, and keeping the stable temperature for 80-110min after controlling the temperature per liter to be 60-90 ℃ in the heating process;
s4, fractional rectification: reducing the temperature of the reaction pipeline part in the S3 to 200-215 ℃ through a rectifying tower, exhausting gas to ensure that the interior of the rectifying tower is in a negative pressure state of 0.75-0.85Mpa, gradually reducing the temperature of a tower kettle in the rectifying tower from the inlet to the outlet of the reaction pipeline to 160-175 ℃ at the end of the rectifying process, and rectifying to obtain a required trifluoromethane product;
the rectifying tower comprises a tower kettle, a reaction pipeline, a sealing diaphragm and a controller, wherein the rectifying tower in S1-S4; a reaction pipeline is arranged in the bottom area of the tower kettle, the radial direction of the reaction pipeline is coincided with the axial direction of the tower kettle, and two ends of the reaction pipeline respectively extend to the outside of the tower kettle; the inlet of the reaction pipeline is communicated with the bottom surface of the tower kettle, and the outlet of the reaction pipeline is communicated with the top surface of the tower kettle; a fractionating pipe communicated with the outlet of the reaction pipeline is arranged between the reaction pipeline and the outlet of the reaction pipeline, the fractionating pipe is overlapped with the axial direction of the tower kettle, and intermittently distributed fractionating guide pipes are also arranged on the pipeline of the fractionating pipe; the fractionating conduit is made of elastic rubber materials, and the section of a pipeline of the fractionating conduit is in a petal shape and is spirally communicated with the fractionating conduit; the tower still is also provided with a sealing diaphragm, the sealing diaphragm is parallel to the end surface of the tower still, and the sealing diaphragm is arranged on the inner wall of the tower still through a ring plate arranged on the circumferential direction of the sealing diaphragm; the inside of the tower kettle where the fractionating guide pipe is positioned is divided into independent cavities by the sealing diaphragm, and a circulating pipe is also arranged on the side wall of the tower kettle between the sealing diaphragms; the circulating pipes are respectively communicated with the temperature control tanks outside the tower kettle, and circulating gas is introduced into independent cavities inside the tower kettle; the controller is used for adjusting the operation of the rectifying tower;
in the prior art, the prepared trifluoromethane contains a plurality of trace elements such as fluoride, simple substances and the like, and all impurities in the trifluoromethane are removed in sequence by adopting an intermittent rectification mode, wherein the boiling points of all compounds and simple substances are relatively close to that of the trifluoromethane, so that the concentration of the trifluoromethane purified by rectification cannot meet the requirement of electronic grade purity required by the semiconductor industry;
therefore, after a primary product of the trifluoromethane is prepared in the reaction pipeline arranged at the bottom of the tower kettle, the circulating heating gas parameters in the temperature control tank are adjusted by the controller, so that the cavities separated by the sealing diaphragm in the tower kettle are in different temperature states, the volume between the independent cavities is changed by the annular plate, and the pressure change in the tower kettle is acted on the fractionating guide pipe by matching with the temperature change of the fractionating guide pipe, so that the fractionating guide pipe made of the elastic rubber material is driven to generate corresponding deformation under the action of the pressure difference between the inside and the outside of the fractionating guide pipe, the state of the fractionating gas is changed, different trace impurities mixed in the trifluoromethane gas are caused to reduce the flow speed in the spiral pipeline of the fractionating guide pipe, and the temperature and the pressure difference between the fractionating guide pipes are separated and attached to the petal-shaped inner wall of the fractionating guide pipe; according to the invention, a reaction pipeline arranged in the rectifying tower is utilized, and the fractionating guide pipes communicated and installed in the tower kettle are matched, so that a trifluoromethane primary product prepared by the reaction pipeline after preheating and activation is directly and sequentially transmitted to the fractionating guide pipes under different temperature and pressure states through the fractionating guide pipes, an adjustable independent cavity is formed in the tower kettle by utilizing the sealing diaphragm, and the independent cavity is adapted to the rectifying conditions required by purification of trifluoromethane under different purity states, and thus the operation effect of the novel preparation method of the electronic grade CHF3 is improved.
Preferably, the center of the sealing diaphragm is provided with an expansion hole, and the sealing diaphragm is in sliding contact with the fractionating pipe through the expansion hole; an annular expansion bag is further mounted in the expansion hole, the interior of the expansion bag is divided into an upper layer and a lower layer which are independent, and through holes are further formed in the two sides of the expansion bag facing the sealing partition plate respectively; when the device is used, the annular plate on the inner wall of the tower kettle is used for adjusting the position of the sealing diaphragm so as to change the pressure of the cavity where the fractionating conduit is located, and the sealing diaphragm deforms under the state of different pressures on the two sides of the sealing diaphragm; through setting up the hole of expanding at sealed diaphragm center, the bloated bag of cooperation installation, receive pressure at sealed diaphragm and when leading to deformation, the change of laminating area between hole and the fractionating tube is compensated to the inflation extrusion through bloated bag, ensure the isolation of sealed diaphragm to the pressure differential state of its both sides cavity, the opening that the bag set up in sealed diaphragm both sides simultaneously expands, the upper and lower both sides that make bloated bag are in under the expansion contraction state of difference, the displacement process of sealed diaphragm under the loop bar drive has been reduced, receive the resistance of the fractionating tube of laminating mutually, thereby the operation effect of electronic grade CHF 3's novel preparation method has been promoted.
Preferably, the outer wall of the fractionating pipe is also provided with spiral raised lines, and grooves formed among the raised lines enable the expansion bags to be clamped in the grooves; the surface of the sealing diaphragm is also provided with inclined raised arc blocks which are distributed along the center of the sealing diaphragm in a surrounding way; when in use, the circulating pipe introduces gases with different temperature parameters into the tower kettle and the adjusted volume of the sealing diaphragm therein to control the state of the cavity of the fractionating conduit; through the burr of setting up the spiral on the fractionating tube outer wall, make sealed diaphragm produce the rotation at the inside lift in-process of tower cauldron to the arc piece through its surface drives the gaseous formation that sealed diaphragm goes out and flows around, the cooperation is through the gaseous temperature variation in the tower cauldron, promotes the gaseous flow in sealed diaphragm formation independent cavity, the thermal convection effect that reinforcing fractionation pipe received, and then strengthened the control by temperature change precision to the fractionation pipe, thereby the operation effect of electronic level CHF 3's novel preparation method has been promoted.
Preferably, the distance between the ends of the fractionating tubes is gradually reduced along the direction towards the outlet, and the pitch of the fractionating guide pipe between the fractionating tubes is also gradually reduced; when in use, the prepared trifluoromethane primary product in the reaction pipeline is purified by a fractionating conduit between fractionating pipes; through setting the fractionating conduit to different screw pitches, the cooperation is installed on the fractionating tube between different distances, makes the pipeline of fractionating conduit change gradually towards the ascending inclination of export orientation along the fractionating tube, is convenient for carry out the speed reduction in stage to the gas mixture that rises in the reaction tube way, and the rectification separation parameter of different materials in the cooperation trifluoromethane avoids weakening the fractionation effect of column bottom top fractionating conduit, and has reduced the backward flow of fraction impurity gas by a wide margin to electronic grade CHF 3's novel preparation method's operational effect has been promoted.
Preferably, the tube wall of the fractionation conduit is also provided with a pressing strip, and the pressing strip is positioned at the petal-shaped corner of the fractionation conduit; the pressure strips are deflected under the action of pressure difference between the inner side and the outer side of the fractionating conduit and respectively protrude out of the inner wall and the outer wall of the fractionating conduit; when the device is used, the separation efficiency of impurity gas mixed in trifluoromethane in a fractionating guide pipe is limited by the heat conducted by the temperature of the pipe wall of the fractionating guide pipe; the pressure strip arranged on the fractionation conduit is enabled to protrude out of the inner wall of the fractionation conduit in the temperature rising process of the fractionation conduit, so that the heat conduction effect of the trifluoromethane primary product gas is increased, the pressure strip protrudes out of the outer wall of the fractionation conduit under the action of negative pressure in the temperature lowering process of the fractionation end section, the heat of the fractionation conduit is conveniently dissipated into a cavity of a tower kettle, and meanwhile, the structural strength of the fractionation conduit in a pressure difference deformation state is enhanced by the pressure strip, so that the operation effect of the novel preparation method of the electronic grade CHF3 is improved.
Preferably, the axial direction of the pressing bar is also provided with a section, and the section protrudes out of the surface of the pressing bar and faces to the inner side of the fractionation conduit; when in use, the inner wall of the fractionating conduit is attached with impurities fractionated from trifluoromethane in the deviation process of the pressing bar; the surface area of the inner wall of the fractionating conduit is further increased by arranging the section protruding from the surface of the pressing strip, and when the pressing strip is deviated and protrudes out of the outer wall of the fractionating conduit, the petal-shaped edges and corners of the fractionating conduit press the surface of the section along with the deflection generated by the pressing strip, so that the impurities attached to the pressing strip and fractionated are extruded and sealed by the section and the inner wall of the fractionating conduit, the falling of the attached impurities caused by the vibration in the deviation process of the pressing strip is avoided, and the operation effect of the novel preparation method of the electronic grade CHF3 is improved.
The invention has the following beneficial effects:
1. according to the invention, through a reaction pipeline arranged in the rectifying tower and a fractionating conduit communicated and installed in a tower kettle, a trifluoromethane primary product prepared by the reaction pipeline after preheating and activation is directly and sequentially transmitted to the fractionating conduit under different temperature and pressure states through the fractionating conduit, and an adjustable independent cavity is formed in the tower kettle by utilizing a sealing diaphragm and is adapted to the rectifying conditions required by the purification of trifluoromethane under different purity states.
2. The invention ensures the isolation of the sealing diaphragm from the pressure difference state of the cavities at the two sides of the sealing diaphragm through the expansion hole arranged at the center of the sealing diaphragm and the matched installation of the expansion bag; the spiral convex patterns are arranged on the outer wall of the fractionating pipe, so that the arc blocks on the surface of the sealing diaphragm drive gas discharged from the sealing diaphragm to form a circumferential flow, and the thermal convection effect on the fractionating pipe is enhanced; the inclination angle of the pipeline of the fractionating conduit along the fractionating pipe in the outlet direction is gradually changed, the fractionating effect of the fractionating conduit at the top of the tower kettle is prevented from being weakened, and the reflux of the fractionated impurity gas is greatly reduced.
3. According to the invention, the layering arranged on the fractionation guide pipe is convenient for heat of the fractionation guide pipe to be dissipated into the cavity of the tower kettle, and meanwhile, the layering also enhances the structural strength of the fractionation guide pipe in a pressure difference deformation state; the section is arranged on the surface of the pressing bar in a protruding mode, so that impurities attached to the pressing bar and fractionated out are extruded and sealed by the section and the inner wall of the fractionation guide pipe, and the phenomenon that the attached impurities fall off due to vibration in the deviation process of the pressing bar is avoided.
Drawings
The invention is further described with reference to the following figures and embodiments.
FIG. 1 is a flow chart of a novel method of making electronic grade CHF3 according to the present invention;
FIG. 2 is a perspective view of a rectifying column in the present invention;
FIG. 3 is a perspective view of a fractionation conduit assembly of the present invention;
FIG. 4 is an enlarged view of a portion of FIG. 2 at A;
in the figure: the device comprises a tower kettle 1, a circulating pipe 11, a temperature control tank 12, a reaction pipeline 2, an inlet 21, an outlet 22, a sealing diaphragm 3, a ring plate 31, an expansion hole 32, an expansion bag 33, a port 331, an arc block 34, a fractionating pipe 4, a convex pattern 41, a fractionating conduit 5, a pressing strip 51 and a section 52.
Detailed Description
In order to make the technical means, the creation characteristics, the achievement purposes and the effects of the invention easy to understand, the invention is further described with the specific embodiments.
As shown in fig. 1 to 4, the novel method for preparing electronic grade CHF3 according to the present invention comprises the following steps:
s1, preheating and activating; introducing nitrogen into the reaction pipeline 2 for circulating purging, heating the reaction pipeline 2 to 180-fold-plus-210 ℃ for more than 30min, then introducing hydrogen fluoride gas into the circulating-purged reaction pipeline 2 for fluorination, controlling the amount of the supplemented hydrogen fluoride gas to account for 30-45% of the internal volume of the reaction pipeline 2, completing filling of the hydrogen fluoride gas within 7-11min, keeping the temperature of the reaction pipeline 2 at 175-fold-plus-205 ℃ for 20min, and completing activation of the reaction pipeline 2;
s2, catalytic synthesis: introducing monochlorodifluoromethane gas into the reaction pipeline 2 of S1 to make the monochlorodifluoromethane gas occupy 25-35% of the volume of the reaction pipeline 2, synthesizing by matching with the catalyst particles preset in the reaction pipeline 2, respectively heating the upper and lower sides of the reaction pipeline 2 to make the temperature of the upper side of the reaction pipeline 2 be 205-225 ℃, the temperature of the lower side of the reaction pipeline 2 be 220-235 ℃, and maintaining for 70-130S; by adding the insufficient amount of the chlorodifluoromethane gas, the hydrogen fluoride gas is prevented from being partially dissolved in the water formed by the reaction between the hydrogen fluoride gas and the chlorodifluoromethane gas to lose the activity of the hydrogen fluoride gas;
s3, controlling the temperature of nitrogen: after the heating of the upper side and the lower side of the reaction pipeline 2 is finished in S2, preparing a primary product of trifluoromethane, continuously introducing nitrogen into the reaction pipeline 2, replacing the gas which does not participate in synthesis in the reaction pipeline 2, heating the reaction pipeline 2 to the temperature of 360-390 ℃, controlling the temperature per liter to be 60-90 ℃ in the heating process, and then keeping the stable temperature for 80-110 min;
s4, fractional rectification: reducing the temperature of the reaction pipeline 2 part in the S3 to 200-215 ℃ through the rectifying tower, exhausting gas to ensure that the interior of the rectifying tower is in a negative pressure state of 0.75-0.85Mpa, gradually reducing the temperature of the tower bottom 1 in the rectifying tower from the inlet 21 to the outlet 22 of the reaction pipeline 2 to 160-175 ℃ at the end of the rectifying process, and rectifying to obtain the required trifluoromethane product;
the rectifying tower in the S4 comprises a tower kettle 1, a reaction pipeline 2, a sealing diaphragm 3 and a controller; a reaction pipeline 2 is arranged in the bottom area of the tower kettle 1, the radial direction of the reaction pipeline 2 is coincided with the axial direction of the tower kettle 1, and two ends of the reaction pipeline 2 respectively extend to the outside of the tower kettle 1; an inlet 21 of the reaction pipeline 2 penetrates through the bottom surface of the tower kettle 1, and an outlet 22 of the reaction pipeline 2 penetrates through the top surface of the tower kettle 1; a fractionating pipe 4 communicated with the reaction pipeline 2 and an outlet 22 of the reaction pipeline is arranged between the reaction pipeline 2 and the tower kettle 1, the fractionating pipe 4 is overlapped with the axial direction of the tower kettle 1, and intermittently distributed fractionating guide pipes 5 are also arranged on a pipeline of the fractionating pipe 4; the fractionating conduit 5 is made of elastic rubber materials, and the section of the pipeline of the fractionating conduit 5 is in a petal shape and is spirally communicated with the fractionating pipe 4; the tower kettle 1 is also provided with a sealing diaphragm 3, the sealing diaphragm 3 is parallel to the end surface of the tower kettle 1, and the sealing diaphragm 3 is arranged on the inner wall of the tower kettle 1 through a ring plate 31 arranged on the circumferential direction of the sealing diaphragm; the inside of the tower kettle 1 where the fractionating conduit 5 is positioned is divided into independent cavities by the sealing diaphragms 3, and a circulating pipe 11 is also arranged on the side wall of the tower kettle 1 between the sealing diaphragms 3; the circulating pipes 11 are respectively communicated with a temperature control tank 12 on the outer side of the tower kettle 1, and circulating gas is introduced into independent cavities in the tower kettle 1; the controller is used for adjusting the operation of the rectifying tower;
in the prior art, the prepared trifluoromethane contains a plurality of trace elements such as fluoride, simple substances and the like, and all impurities in the trifluoromethane are removed in sequence by adopting an intermittent rectification mode, wherein the boiling points of all compounds and simple substances are relatively close to that of the trifluoromethane, so that the concentration of the trifluoromethane purified by rectification cannot meet the requirement of electronic grade purity required by the semiconductor industry;
therefore, the invention, through the reaction pipeline 2 arranged at the bottom of the tower kettle 1, after the primary product of the trifluoromethane is prepared, the parameters of the circulating heating gas in the temperature control tank 12 are adjusted by the controller, so that the cavity body separated by the sealing diaphragm 3 in the tower kettle 1 is in different temperature states, the volume between the independent cavities is changed through the annular plate 31, the pressure change in the tower kettle 1 is acted on the fractionating guide pipe 5 by matching with the temperature change of the fractionating guide pipe 5, the fractionating guide pipe 5 made of the elastic rubber material is driven to generate corresponding deformation under the action of the pressure difference between the inside and the outside of the fractionating guide pipe, the state of the fractionating gas is changed, and different trace impurities are mixed in the trifluoromethane gas, the flow speed of the fractionation guide pipe 5 is reduced in the spiral pipeline, so that the fractionation guide pipe 5 is separated out under the action of temperature and pressure difference and attached to the petal-shaped inner wall of the fractionation guide pipe; according to the invention, the reaction pipeline 2 arranged in the rectifying tower is utilized, and the fractionating guide pipe 5 communicated and installed in the tower kettle 1 is matched, so that the trifluoromethane primary product prepared by preheating and activating the reaction pipeline 2 is directly and sequentially transmitted to the fractionating guide pipes 5 under different temperature and pressure states through the fractionating pipe 4, an adjustable independent cavity is formed in the tower kettle 1 by utilizing the sealing diaphragm 3, and the rectifying condition required by purification of trifluoromethane under different purity states is adapted, and thus the operation effect of the novel preparation method of the electronic grade CHF3 is improved.
As an embodiment of the present invention, an expansion hole 32 is opened at the center of the sealing membrane 3, and the sealing membrane 3 is in sliding contact with the fractionating pipe 4 through the expansion hole 32; an annular expansion bag 33 is further installed in the expansion hole 32, the interior of the expansion bag 33 is divided into an upper layer and a lower layer which are independent, and through holes 331 are further formed in the two sides, facing the sealing partition plate, of the expansion bag 33 respectively; when the device is used, the annular plate 31 on the inner wall of the tower kettle 1 is used for adjusting the position of the sealing diaphragm 3 so as to change the pressure of the cavity where the fractionating conduit 5 is located, and the sealing diaphragm 3 deforms under the state of the different pressures on the two sides; through setting up the hole 32 that expands at sealed diaphragm 3 center, the bloated bag 33 of cooperation installation, when sealed diaphragm 3 received pressure and lead to deformation, the change of laminating area between hole 32 and fractionating tube 4 is compensated through the inflation extrusion of bloating bag 33, ensure sealed diaphragm 3 to the isolation of the pressure differential state of its both sides cavity, the bag 33 that expands simultaneously is at the opening 331 that sealed diaphragm 3 both sides set up, make the upper and lower both sides of bloating bag 33 be in under the inflation contraction state of difference, the displacement process of sealed diaphragm 3 under the drive of crown plate 31 has been reduced, receive the resistance of the fractionating tube 4 of laminating mutually, thereby the operational effect of the novel preparation method of electronic grade CHF3 has been promoted.
In one embodiment of the present invention, the outer wall of the fractionating tube 4 is further provided with spiral ridges 41, and grooves formed between the ridges 41 allow the ballooning 33 to be inserted therein; the surface of the sealing diaphragm 3 is also provided with inclined convex arc blocks 34, and the arc blocks 34 are distributed around the center of the sealing diaphragm 3; when in use, the circulating pipe 11 feeds gases with different temperature parameters into the tower kettle 1, and the adjusted volume of the sealing diaphragm 3 in the circulating pipe controls the state of the cavity of the fractionating guide pipe 5; through setting up the burr 41 of spiral on the 4 outer walls of fractionating tube, make sealed diaphragm 3 produce the rotation at the inside lift in-process of tower cauldron 1, and the arc block 34 through its surface drives the gaseous formation that sealed diaphragm 3 goes out and flows around, the cooperation is through the gaseous temperature variation in tower cauldron 1, promote the gaseous flow in sealed diaphragm 3 formation independent cavity, the thermal convection effect that reinforcing fractionating pipe 5 received, and then strengthened the control by temperature change precision to fractionating pipe 5, thereby the operation effect of the novel preparation method of electron level CHF3 has been promoted.
In one embodiment of the present invention, the distance between the ends of the fractionation tubes 4 is gradually reduced in the direction toward the outlet 22, and the pitch of the fractionation conduit 5 between the fractionation tubes 4 is also gradually reduced; when in use, the prepared trifluoromethane primary product in the reaction pipeline 2 is purified by the fractionating conduit 5 between the fractionating pipes 4; through setting the fractionating guide pipe 5 into different screw pitches, the matching is installed on the fractionating pipe 4 among different distances, the pipeline of the fractionating guide pipe 5 gradually changes towards the ascending inclination angle of the outlet 22 direction along the fractionating pipe 4, the speed reduction of stages is conveniently carried out on the mixed gas rising in the reaction pipeline 2, the rectification separation parameters of different substances in the trifluoromethane are matched, the fractionation effect of the fractionating guide pipe 5 at the top of the tower kettle 1 is avoided being weakened, the reflux of the fractionated impurity gas is greatly reduced, and the operation effect of the novel preparation method of the electronic grade CHF3 is improved.
As an embodiment of the present invention, a batten 51 is further disposed on the tube wall of the fractionation conduit 5, and the batten 51 is located at the petal-shaped corner of the fractionation conduit 5; the pressure strips 51 are deflected under the action of the pressure difference between the inner side and the outer side of the fractionating conduit 5 and respectively protrude out of the inner wall and the outer wall of the fractionating conduit 5; when in use, the separation efficiency of the impurity gas mixed in the trifluoromethane in the fractionating conduit 5 is limited by the heat conducted by the temperature of the tube wall; the pressure strip 51 arranged on the fractionating conduit 5 protrudes out of the inner wall of the fractionating conduit 5 in the temperature rising process of the fractionating conduit 5, so that the heat conduction effect of the primary trifluoromethane gas is increased, and in the temperature lowering process of the final stage of the fractional distillation, the pressure strip 51 protrudes out of the outer wall of the fractionating conduit 5 under the negative pressure effect, so that the heat of the fractionating conduit 5 is conveniently dissipated into the cavity of the tower kettle 1, meanwhile, the pressure strip 51 also enhances the structural strength of the fractionating conduit 5 in the pressure difference deformation state, and the operation effect of the novel preparation method of the electronic grade CHF3 is improved.
As an embodiment of the present invention, the bead 51 is further provided with a cut-off piece 52 in the axial direction, and the cut-off piece 52 protrudes from the surface of the bead 51 and faces the inner side of the fractionation conduit 5; when in use, the inner wall of the fractionating conduit 5 is attached with impurities fractionated from trifluoromethane during the shifting process of the pressure bar 51; the surface area of the inner wall of the fractionating conduit 5 is further increased by arranging the section 52 protruding from the surface of the pressing strip 51, and when the pressing strip 51 protrudes out of the outer wall of the fractionating conduit 5 in a deviating manner, the petal-shaped edges of the fractionating conduit 5 press the surface of the section 52 along with the deflection generated by the pressing strip 51, so that the impurities attached to the pressing strip 51 and fractionated are extruded and sealed by the section 52 and the inner wall of the fractionating conduit 5, the phenomenon that the attached impurities fall off due to vibration in the process of deviating the pressing strip 51 is avoided, and the operation effect of the novel preparation method of the electronic grade CHF3 is improved.
When in use, after a primary product of the trifluoromethane is prepared in the reaction pipeline 2 arranged at the bottom of the tower kettle 1, the parameters of the circulating heating gas in the temperature control tank 12 are adjusted by the controller, so that the cavity body separated by the sealing diaphragm 3 in the tower kettle 1 is in different temperature states, the volume between the independent cavities is changed through the annular plate 31, the pressure change in the tower kettle 1 is acted on the fractionating guide pipe 5 by matching with the temperature change of the fractionating guide pipe 5, the fractionating guide pipe 5 made of the elastic rubber material is driven to generate corresponding deformation under the action of the pressure difference between the inside and the outside of the fractionating guide pipe, the state of the fractionating gas is changed, and different trace impurities are mixed in the trifluoromethane gas, the flow speed of the fractionation guide pipe 5 is reduced in the spiral pipeline, so that the fractionation guide pipe 5 is separated out under the action of temperature and pressure difference and attached to the petal-shaped inner wall of the fractionation guide pipe; the expansion hole 32 arranged in the center of the sealing diaphragm 3 is matched with the expansion bag 33, when the sealing diaphragm 3 deforms under pressure, the change of the joint area between the expansion hole 32 and the fractionating tube 4 is compensated through the expansion extrusion of the expansion bag 33, the isolation of the sealing diaphragm 3 to the pressure difference state of the cavities on the two sides of the sealing diaphragm is ensured, meanwhile, the expansion bag 33 is provided with the through holes 331 on the two sides of the sealing diaphragm 3, so that the upper side and the lower side of the expansion bag 33 are in different expansion and contraction states, the displacement process of the sealing diaphragm 3 driven by the ring plate 31 is reduced, and the sealing diaphragm is subjected to the resistance of the jointed fractionating tube 4; the spiral convex pattern 41 is arranged on the outer wall of the fractionating pipe 4, so that the sealing diaphragm 3 rotates in the lifting process of the inner part of the tower kettle 1, the arc block 34 on the surface of the sealing diaphragm drives the gas out of the sealing diaphragm 3 to form a circumfluence, and the gas flowing in an independent cavity formed by the sealing diaphragm 3 is promoted by matching the temperature change of the gas in the tower kettle 1, the thermal convection effect on the fractionating conduit 5 is enhanced, and the temperature control precision on the fractionating conduit 5 is further enhanced; the fractionating guide pipes 5 are arranged into different screw pitches and are matched with the fractionating pipes 4 arranged among different distances, so that the inclination angles of the pipelines of the fractionating guide pipes 5 along the fractionating pipes 4 in the direction towards the outlet 22 are gradually changed, the rising mixed gas in the reaction pipeline 2 is conveniently decelerated in stages, the fractionating effect of the fractionating guide pipes 5 on the top of the tower kettle 1 is prevented from being weakened by matching with the rectification separation parameters of different substances in the trifluoromethane, and the reflux of the fractionated impurity gas is greatly reduced; the pressure strip 51 arranged on the fractionating conduit 5 is enabled to protrude out of the inner wall of the fractionating conduit 5 in the temperature rising process of the fractionating conduit 5, so that the heat conduction effect of the trifluoromethane primary product gas is increased, and the pressure strip 51 protrudes out of the outer wall of the fractionating conduit 5 under the negative pressure effect in the temperature lowering process of the final stage of the fractional distillation, so that the heat of the fractionating conduit 5 is conveniently dissipated into the cavity of the tower kettle 1, and meanwhile, the pressure strip 51 also enhances the structural strength of the fractionating conduit 5 in the pressure difference deformation state; the section 52 which is arranged on the surface of the pressing strip 51 and protrudes out further increases the surface area of the inner wall of the fractionating conduit 5, and when the pressing strip 51 protrudes out of the outer wall of the fractionating conduit 5 in a deviating way, the petal-shaped edges of the fractionating conduit 5 press the surface of the section 52 along with the deflection generated by the pressing strip 51, so that the impurities which are attached to the pressing strip 51 and distilled off are extruded and sealed by the section 52 and the inner wall of the fractionating conduit 5, and the dropping of the attached impurities caused by the vibration in the deviating process of the pressing strip 51 is avoided.
The foregoing illustrates and describes the principles, general features, and advantages of the present invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (6)
1. A novel preparation method of electronic grade CHF3 is characterized in that: the method comprises the following steps:
s1, preheating and activating; introducing nitrogen into the reaction pipeline (2) for circulating purging, heating the reaction pipeline (2) to 180-class 210 ℃ for more than 30min, then introducing hydrogen fluoride gas into the circulating purged reaction pipeline (2) for fluorination, controlling the amount of supplemented hydrogen fluoride gas to account for 30-45% of the internal volume of the reaction pipeline (2), completing filling of the hydrogen fluoride gas within 7-11min, keeping the temperature of the reaction pipeline (2) at 175-class 205 ℃ for 20min, and completing activation of the reaction pipeline (2);
s2, catalytic synthesis: introducing monochlorodifluoromethane gas into the reaction pipeline (2) of S1 to make the monochlorodifluoromethane gas occupy 25-35% of the volume of the reaction pipeline (2), synthesizing by matching with catalyst particles preset in the reaction pipeline (2), respectively heating the two sides of the upper part and the lower part of the reaction pipeline (2), respectively making the temperature of the upper part of the reaction pipeline (2) at 205-;
s3, controlling the temperature of nitrogen: after heating the upper side and the lower side of the reaction pipeline (2) in S2, preparing a primary product of trifluoromethane, continuously introducing nitrogen into the reaction pipeline (2), replacing the participated gas which does not participate in synthesis in the reaction pipeline (2), heating the reaction pipeline (2) to the temperature of 360-390 ℃, controlling the temperature per liter to be 60-90 ℃ in the heating process, and then keeping the stable temperature for 80-110 min;
s4, fractional rectification: reducing the temperature of the reaction pipeline (2) part in the S3 to 200-215 ℃ through a rectifying tower, exhausting gas to ensure that the interior of the rectifying tower is in a negative pressure state of 0.75-0.85Mpa, gradually reducing the temperature of a tower bottom (1) in the rectifying tower from an inlet (21) to an outlet (22) of the reaction pipeline (2) to 160-175 ℃ at the tail stage of the rectifying process, and rectifying to obtain a required trifluoromethane product;
the rectifying tower comprises a tower kettle (1), a reaction pipeline (2), a sealing diaphragm (3) and a controller, wherein the rectifying tower is from S1 to S4; a reaction pipeline (2) is arranged in the bottom area of the tower kettle (1), the radial direction of the reaction pipeline (2) is coincident with the axial direction of the tower kettle (1), and two ends of the reaction pipeline (2) respectively extend to the outside of the tower kettle (1); an inlet (21) of the reaction pipeline (2) penetrates through the bottom surface of the tower kettle (1), and an outlet (22) of the reaction pipeline (2) penetrates through the top surface of the tower kettle (1); a fractionating pipe (4) communicated with the reaction pipeline (2) and an outlet (22) of the reaction pipeline is arranged between the reaction pipeline and the tower kettle, the fractionating pipe (4) is overlapped with the axial direction of the tower kettle (1), and the pipeline of the fractionating pipe (4) is also provided with intermittently arranged fractionating guide pipes (5); the fractionating guide pipe (5) is made of elastic rubber materials, the section of the pipeline of the fractionating guide pipe (5) is in a petal shape and is spirally communicated with the fractionating pipe (4); the tower kettle (1) is also internally provided with a sealing diaphragm (3), the sealing diaphragm (3) is parallel to the end surface of the tower kettle (1), and the sealing diaphragm (3) is arranged on the inner wall of the tower kettle (1) through a ring plate (31) arranged on the circumferential direction of the sealing diaphragm; the inside of the tower kettle (1) where the fractionating guide pipe (5) is positioned is divided into independent cavities by the sealing diaphragms (3), and a circulating pipe (11) is also arranged on the side wall of the tower kettle (1) between the sealing diaphragms (3); the circulating pipes (11) are respectively communicated with a temperature control tank (12) on the outer side of the tower kettle (1), and circulating gas is introduced into independent cavities in the tower kettle (1); the controller is used for adjusting the operation of the rectifying tower.
2. A novel method of making electronic grade CHF3, according to claim 1, wherein: an expansion hole (32) is formed in the center of the sealing diaphragm (3), and the sealing diaphragm (3) is in sliding contact with the fractionating pipe (4) through the expansion hole (32); an annular expansion bag (33) is further installed in the expansion hole (32), the interior of the expansion bag (33) is divided into an upper layer and a lower layer which are independent, and through holes (331) are further formed in the two sides, facing the sealing partition plate, of the expansion bag (33) respectively.
3. A novel method of manufacturing electronic grade CHF3, according to claim 2, wherein: the outer wall of the fractionating pipe (4) is also provided with spiral wales (41), and grooves formed among the wales (41) enable the expansion bags (33) to be clamped in the grooves; the surface of the sealing diaphragm (3) is also provided with inclined convex arc blocks (34), and the arc blocks (34) are distributed around the center of the sealing diaphragm (3).
4. A novel method of manufacturing electronic grade CHF3, according to claim 3, wherein: the distance between the ends of the fractionating pipes (4) is gradually reduced along the direction towards the outlet (22), and the pitch of the fractionating guide pipe (5) between the fractionating pipes (4) is also gradually reduced.
5. A novel method of making electronic grade CHF3, according to claim 4, wherein: the tube wall of the fractionating guide tube (5) is also provided with a pressing strip (51), and the pressing strip (51) is positioned at the petal-shaped corner of the fractionating guide tube (5); the pressure strips (51) are deflected under the action of pressure difference between the inner side and the outer side of the fractionating guide pipe (5) and respectively protrude out of the inner wall and the outer wall of the fractionating guide pipe (5).
6. A novel method of making electronic grade CHF3, according to claim 5, wherein: the axial direction of the pressing strip (51) is also provided with a section (52), and the section (52) protrudes out of the surface of the pressing strip (51) and faces the inner side of the fractionating conduit (5).
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| CN114133314A (en) * | 2021-11-02 | 2022-03-04 | 山东东岳化工有限公司 | Purification device and purification process for electronic-grade trifluoromethane |
| CN114995131A (en) * | 2022-05-25 | 2022-09-02 | 福建德尔科技股份有限公司 | Rectification control system for preparing electronic-grade trifluoromethane and control method thereof |
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