Process and device for preparing ultra-high purity carbonyl sulfide from industrial carbonyl sulfide

Abstract

The application discloses a process and device for preparing super-high-purity carbonyl sulfide from industrial carbonyl sulfide, wherein metal ions and water are removed through pretreatment, then light and heavy components are removed through multi-stage rectification, and then low-content oxygen and water impurities are removed through post-treatment to improve purity. In addition, at the end of the multi-stage rectification process, light components are obtained to avoid the difficulty in removing metal ions caused by the rectification tower itself, so that the defects of low product purity and incomplete rectification effect in the prior art are effectively solved, and the industrial preparation process of super-high-purity carbonyl sulfide is promoted.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ultra-high purity carbonyl sulfide preparation, in particular to a process and device for preparing ultra-high purity carbonyl sulfide from industrial carbonyl sulfide. BACKGROUND

[0002] With the rapid development of semiconductor very large scale integrated circuits and memory chips, high-purity carbonyl sulfide is widely used in the etching process of line miniaturization in the technical field of 12-inch integrated circuit semiconductors. It has very obvious etching effect in dry etching, and replaces fluorinated etching gas which is difficult to degrade and has greenhouse effect. In the semiconductor industry, it is an important precursor for preparing CdS, Cr2S3, MnS and other thin films by chemical vapor deposition method, and a side wall protection gas in dry etching process.

[0003] Ultra-high purity electronic-grade carbonyl sulfide generally has a purity of at least 99.99% (4N grade) or above,

[0004] The purity of ultra-high purity carbonyl sulfide used in the above-mentioned manufacturing process is required to be higher and higher, and the content of impurities such as total hydrocarbon, moisture and metal ions should be as low as possible. In the ACL (amorphous carbon layer) etching, a small amount of metal particle impurities will be embedded in the carbon layer lattice during the etching process, affecting the conductivity of the substrate and the performance of the silicon dioxide insulating layer. Therefore, efficient and stable carbonyl sulfide purification technology has always been the focus of research in the field of purification of electronic special gases.

[0005] Chinese patent document CN198786665A discloses a method for manufacturing high-purity carbonyl sulfide. After carbonyl sulfide is synthesized by using a sulfur melting device and a reactor, it is purified by entering a condenser and a separation cold trap, and finally high-purity carbonyl sulfide is obtained in a product collector. The separation process is relatively simple, and only one step of condensation method is used to remove light component impurities (non-condensable gas) in carbonyl sulfide, while there is no any purification process for heavy component impurities (such as metal ions and moisture) in carbonyl sulfide component, resulting in low product purity, only 99.5%.

[0006] Chinese patent document CN109231207A discloses a method for preparing high-purity carbonyl sulfide. Carbon monoxide and sulfur are reacted under the condition of using a metal sulfide as a catalyst, and 99.99% high-purity carbonyl sulfide is obtained by low-temperature condensation, low-temperature heavy component removal and light component removal rectification. In the purification process, ultra-low temperature is used, so liquid nitrogen is used as a refrigerant, and the equipment and valves have high requirements for low temperature resistance. At the same time, the product material is collected from the tower kettle after the light component is removed, and the content of metal impurities and moisture impurities is high, which cannot meet the use requirements of the semiconductor industry.

[0007] Chinese patent document CN110862087A discloses a method for synthesizing carbonyl sulfide by using a mixture of toluene, 2-mercapto-6-chlorobenzoxazole and DMF, and preparing high-purity carbonyl sulfide by using compression and single-stage rectification. The single-stage condensation and single-stage rectification method used in the method cannot completely remove the light (such as HCl) and heavy (such as organic matter) impurities entrained in the synthesis material, and the purity of the product prepared is not high, only 99.9%.

[0008] In the prior art industrial carbonyl sulfide synthesis process, ferrous sulfide (FeS) and ferrous sulfide (FeS2) are used as catalysts, and the industrial-grade carbonyl sulfide obtained contains about 200 ppm of Fe ions, which cannot be reduced to ppt level by normal rectification method, and the product cannot meet the requirements of advanced semiconductor processes for ultra-high purity carbonyl sulfide.

[0009] Chinese patent document CN208667111U discloses a purification device for carbonyl sulfide, which uses a simple raw material bottle group, a cooler and an adsorber to purify the crude product. The process only uses simple evaporation, single-stage adsorption and condensation process, which cannot effectively remove the light and heavy impurities in the carbonyl sulfide raw material. At the same time, due to the use of only one adsorbent, the selective adsorption capacity of the adsorbent for impurities is limited, and various impurities in the raw material cannot be completely adsorbed, resulting in low product purity.

[0010] Therefore, it is necessary to propose a preparation process of ultra-high purity carbonyl sulfide to solve the technical problems of low product purity and incomplete rectification effect in the carbonyl sulfide purification process. SUMMARY

[0011] The present application provides a process and device for preparing ultra-high purity carbonyl sulfide from industrial carbonyl sulfide, which solves the technical problems of low product purity and incomplete rectification effect in the prior art.

[0012] To achieve the above-mentioned purpose, the scheme of the present application is as follows:

[0013] A process for preparing ultra-high purity carbonyl sulfide from industrial carbonyl sulfide, comprising the following steps:

[0014] S1. Removing metal ions and water impurities from the industrial carbonyl sulfide after vaporization;

[0015] S2. Carrying out several times of rectification on the impurity-removed carbonyl sulfide; the rectification process comprises at least one step of removing heavy components and at least one step of removing light components;

[0016] S3. Obtaining ultra-high purity carbonyl sulfide by removing water and oxygen impurities from the rectified carbonyl sulfide.

[0017] Further, the light components obtained at the end of the rectification process in step S2 enter step S3.

[0018] Further, the rectification process in step S2 includes three times, and the processes are as follows:

[0019] In the first time of rectification, the heavy component is removed, and the light component is subjected to the second time of rectification;

[0020] In the second time of rectification, the light component is removed, and the heavy component is subjected to the third time of rectification;

[0021] In the third time of rectification, the heavy component is removed, and the light component is obtained.

[0022] Preferably, in the rectification process in step S2: in the first time of rectification, the operating pressure is 0.8-1.8 MPa, the overhead temperature is 12-42℃, and the bottom temperature is 13-45℃; in the second time of rectification, the operating pressure is 0.7-1.7 MPa, the overhead temperature is 10-39℃, and the bottom temperature is 12-42℃; in the third time of rectification, the operating pressure is 0.4-1.5 MPa, the overhead temperature is -9-34℃, and the bottom temperature is -7-32℃.

[0023] Further, in step S1, the impurity removal process reduces the iron ion impurity to below 100 ppb and reduces the moisture impurity to below 10 ppm; in step S3, the impurity removal process reduces the water and oxygen impurities to below 10 ppb, respectively.

[0024] Further, the process for preparing ultra-high-purity carbonyl sulfide further comprises a step of recovering carbonyl sulfide by-product: the heavy component and the light component removed in the rectification process are compressed and condensed to obtain the recovered carbonyl sulfide by-product.

[0025] Another object of the present application is to provide a device for preparing ultra-high-purity carbonyl sulfide from industrial carbonyl sulfide, comprising a pretreatment unit, a rectification unit and a post-treatment unit connected in sequence.

[0026] The pretreatment unit is used for removing metal ion and moisture impurities.

[0027] The rectification unit comprises a plurality of rectification columns connected in sequence, which are used for removing the heavy component at least once and removing the light component at least once.

[0028] The post-treatment unit is used for removing water and oxygen impurities.

[0029] Further, the rectification unit comprises a first rectification column, a second rectification column and a third rectification column connected in sequence; the overhead of the first rectification column is connected to the second rectification column, the bottom of the second rectification column is connected to the third rectification column, and the overhead of the third rectification column is connected to the post-treatment unit.

[0030] Preferably, the device further comprises a by-product recovery unit comprising a compressor, a condenser and a storage tank connected in sequence; the input end of the compressor is connected with the column bottom of the first and second rectifying columns and the column top of the second rectifying column respectively, and the output end of the compressor is connected with the condenser.

[0031] Further, the pre-treatment unit comprises a resin adsorber and a molecular sieve adsorber connected in sequence; and the post-treatment unit comprises a purifier filled with rare earth metal compounds.

[0032] Compared with the prior art, the beneficial effects of the present application include but are not limited to:

[0033] The method for preparing ultra-high purity carbonyl sulfide provided by the present application can effectively solve the defects of the prior art, such as low product purity and incomplete rectification effect, by removing metal ions and water in the pre-treatment, then removing low-content oxygen and water impurities in the post-treatment after light and heavy components are removed through multi-stage rectification.

[0034] In the method for preparing ultra-high purity carbonyl sulfide provided by the present application, three-stage rectification is adopted in the rectification process, and the last stage of rectification can avoid the problem of affecting the product purity caused by the metal impurities brought into the rectifying column itself by obtaining light components, and has strong reliability.

[0035] The method for preparing ultra-high purity carbonyl sulfide provided by the present application fully utilizes the by-products in the rectification process, and the carbonyl sulfide by-products can be obtained through simple collection and treatment, promoting circular economy and being suitable for industrialization. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 The figure is a product path schematic diagram of the device for preparing ultra-high purity carbonyl sulfide.

[0037] Figure 2 The figure is a by-product path schematic diagram of the device for preparing ultra-high purity carbonyl sulfide.

[0038] The marks in the figure are as follows: 1, vaporizer; 2, resin adsorber; 3, molecular sieve adsorber; 4, first rectifying column; 5, second rectifying column; 6, first condenser; 7, third rectifying column; 8, purifier; 9, compressor; 10, second condenser; 11, storage tank; 41, first extraction pipe; 62, second extraction pipe; 71, third extraction pipe. DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0040] It should be understood that the terms "upper", "lower", "top", "bottom", "inner", "outer" and the like indicate an orientation or positional relationship based on the orientation or position shown in the drawings, and are used only for the purpose of facilitating the description and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0041] It should also be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing", "setting" and the like should be broadly understood, for example, it can be fixed connection, or detachable connection, or integral; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two components or the interaction relationship between two components. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0042] Based on the prior art industrial carbonyl sulfur (purity above 95%) synthesis process, ferrous sulfide (FeS) and ferrous sulfide (FeS2) are used as catalysts, and thus the industrial grade carbonyl sulfur obtained contains about 200 ppm of Fe ion, which cannot be reduced to ppb level by normal rectification method, and the product cannot meet the requirements of advanced semiconductor process for ultra-pure carbonyl sulfur. In addition, the carbonyl sulfur in the above process has heavy components (water, carbon disulfide, metal sulfide) and light components (N2, O2, Ar, CO, CO2, CH4) which are difficult to separate, affecting the improvement of carbonyl sulfur purity. In order to solve the problem of low purity of carbonyl sulfur purified by the prior art and the difficulty of purifying industrial carbonyl sulfur containing the above impurities, the present application provides the following scheme:

[0043] In one embodiment, a process for preparing ultra-pure carbonyl sulfur from industrial carbonyl sulfur is provided, comprising the following steps:

[0044] S1. Removing metal ions and water impurities from industrial carbonyl sulfur after vaporization;

[0045] S2. Rectifying the impurity-removed carbonyl sulfur several times; the rectification process includes at least one step of removing heavy components and at least one step of removing light components;

[0046] S3. Obtaining ultra-pure carbonyl sulfur by removing water and oxygen impurities from the rectified carbonyl sulfur.

[0047] The method for preparing ultra-pure carbonyl sulfur removes metal iron ions and water by pretreatment, then removes light and heavy components by multi-stage rectification, and finally removes low content of oxygen and water impurities by post-treatment to obtain ultra-pure carbonyl sulfur, which can effectively solve the defects of low product purity and incomplete rectification effect in the prior art.

[0048] In a preferred embodiment, the light ends in step S2 are taken into step S3. The last stage of rectification can avoid the problem of the rectification column itself bringing in metal impurities affecting the purity of the product, and is highly reliable.

[0049] In a preferred embodiment, the rectification process in step S2 includes three times, and the process is as follows:

[0050] In the first rectification, the heavy components are removed, and the light components are subjected to a second rectification;

[0051] In the second rectification, the light components are removed, and the heavy components are subjected to a third rectification;

[0052] In the third rectification, the heavy components are removed, and the light components are taken.

[0053] The operating conditions and parameters of the above three rectification processes are designed according to the ultra-high purity carbonyl sulfide standard, and are specifically designed according to the impurity content of the light components and the heavy components, so as to achieve the requirement that the impurity content of the light components and the heavy components is lower than the standard.

[0054] In a more preferred embodiment, in the rectification process in step S2: in the first rectification, the operating pressure is 0.8-1.8 MPa, the overhead temperature is 12-42℃, and the column bottom temperature is 13-45℃, which is used to remove each heavy component impurity to below 5-10 ppm; in the second rectification, the operating pressure is 0.7-1.7 MPa, the overhead temperature is 10-39℃, and the column bottom temperature is 12-42℃, which is used to remove the light component impurity to below 1-2 ppm; in the third rectification, the operating pressure is 0.4-1.5 MPa, the overhead temperature is -9-32℃, and the column bottom temperature is -7-34℃. This process further removes the heavy component impurity to below 1-2 ppm. The above pressures are all absolute pressures, and the same applies below.

[0055] In a preferred embodiment, in the process for preparing ultra-high purity carbonyl sulfide, the impurity removal process in step S1 reduces the iron ion impurity to below 100 ppb and the water impurity to below 10 ppm; and the impurity removal process in step S3 reduces the water and oxygen impurities to below 10 ppb, respectively, so that the purity of the finally obtained ultra-high purity carbonyl sulfide product is above 99.999% (5N).

[0056] In a preferred embodiment, the process for preparing ultra-high purity carbonyl sulfide further includes a step of recovering carbonyl sulfide by-products: the heavy components and the light components removed in the rectification process are compressed and condensed to obtain the recovered carbonyl sulfide by-products. The carbonyl sulfide by-products can be obtained by simple collection and treatment, promote circular economy, and are suitable for industrialization.

[0057] In another embodiment, as Figure 1As shown, a device for preparing ultra-high purity carbonyl sulfide from industrial carbonyl sulfide is provided, which comprises a vaporizer 1, a resin adsorber 2, a molecular sieve adsorber 3, a multi-stage rectification tower and a purifier 8 connected in sequence; the multi-stage rectification tower comprises a first rectification tower 4, a second rectification tower 5 and a third rectification tower 7 connected in sequence; the top of the first rectification tower 4 is connected to the second rectification tower 5, the bottom of the second rectification tower 5 is connected to the third rectification tower 7, and the top of the third rectification tower 7 is connected to the purifier 8.

[0058] In the above device, the resin adsorber 2 is filled with a mixture of new ultra-high cross-linked polystyrene macroporous adsorption resin and complex adsorption resin, which is used to adsorb metal iron ions; the molecular sieve adsorber 3 is filled with modified molecular sieve, such as 3A zeolite molecular sieve, which is used to adsorb water. The purifier 8 is filled with rare earth metal compounds, such as small-pore silicon-aluminum-silicate, which is used to remove oxygen and water.

[0059] In the preferred embodiment, the mass ratio of macroporous adsorption resin to complex adsorption resin is 1: (0.5-1.5), the macroporous adsorption resin has a single molecular weight of 40,000-60,000, and the complex adsorption resin has a molecular weight of 85,000-110,000. The iron metal ions can be effectively removed to below 100 ppb.

[0060] In the preferred embodiment, the bottom of the first rectification tower 4 is provided with a first outlet pipe 41; the top of the second rectification tower 5 is provided with a first condenser 6, the top of the second rectification tower 5 is connected to the feed end of the first condenser 6 through a top outlet pipe 61, and the discharge end of the first condenser 6 is connected to the top of the second rectification tower 5 through a top reflux pipe 63 to form reflux. The condensation temperature of the first condenser 6 is set to be slightly lower than the boiling point temperature of carbonyl sulfide, so that the light components form non-condensable gas. The discharge end of the first condenser 6 is also provided with a second outlet pipe 62; the bottom of the third rectification tower 7 is provided with a third outlet pipe 71. The first outlet pipe 41 and the third outlet pipe 71 respectively extract the heavy components from the bottom, and the second outlet pipe 62 is used to extract the light components from the top.

[0061] In another embodiment, as shown in Figure 2 the first outlet pipe 41, the second outlet pipe 62 and the third outlet pipe 71 in the above embodiment are respectively connected to the input end of a compressor 9, the output end of the compressor 9 is connected to a second condenser 10, and the second condenser 10 is connected to a storage tank 11, which is used to recover and produce industrial carbonyl sulfide by-products from the crude carbonyl sulfide containing heavy components or light components in the first outlet pipe 41, the second outlet pipe 62 and the third outlet pipe 71.

[0062] As a conventional design in the art, the above-mentioned device for preparing or recovering ultrahigh-purity carbonyl sulfide further comprises necessary valves for pipeline control and instruments for display. The refrigerant for cooling or condensation can be low-temperature water, low-temperature oil or directly using low-temperature freon, etc. The heating medium for vaporization or rectification can be steam, hot water, hot oil, electric heater, etc.

[0063] In operation, the industrial carbonyl sulfide is delivered to the vaporizer 1 through a pipeline, vaporized to form a gaseous state at 1.0-2.0 MPa, and then delivered to the resin adsorber 2 to remove iron ions to a content of less than 100 ppb, and then delivered to the molecular sieve adsorber 3 to remove water to a content of less than 10 ppm. The pretreated carbonyl sulfide enters the rectification stage, and in the rectification process, the first rectification column 4, the second rectification column 5 and the third rectification column 7 are set at the pressure and temperature intervals as described in the preparation process embodiment. When the carbonyl sulfide enters the first rectification column 4 for the first time, the heavy components (water, carbon disulfide, metal sulfides) contained in the carbonyl sulfide in the column bottom are delivered to the compressor 9 through the first take-off pipe 41, and the overhead is delivered to the second rectification column 5. The overhead of the second rectification column 5 is condensed into a liquid state by the first condenser 6 and then returned to the column, and another part is taken out through the second take-off pipe 62 and delivered to the compressor 9. In this process, due to the effect of the condenser, the remaining non-condensable gas carries the light component impurities (N2, O2, Ar, CO, CO2, CH4) into the second take-off pipe 62. The material after extraction of the light components by the first rectification column 4 and extraction of the heavy components by the second rectification column 5 enters the third rectification column 7 for the third rectification and extraction of light components, and the heavy components produced in the column bottom are taken out through the third take-off pipe 71 and delivered to the compressor 9, and the light components produced in the column top enter the purifier 8, and after the water and oxygen impurities are reduced to 10 ppb by the purifier, the high-purity carbonyl sulfide (5N) product is delivered. The carbonyl sulfide crude product containing light component or heavy component impurities taken out through the first take-off pipe 41, the second take-off pipe 62 and the third take-off pipe 71 is pressurized to 1.3-2.0 MPa by the compressor and then enters the second condenser 10 for liquefaction, and the liquefied material is then delivered to the storage tank 11 as a low-grade industrial carbonyl sulfide byproduct for sale or reuse in the upstream section.

[0064] Although the embodiments of the present application have been shown and described, it is to be understood that various changes, modifications, substitutions and variations can be made in these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A process for the preparation of ultra-high purity carbonyl sulfide from technical carbonyl sulfide, characterized in that the steps The application relates to a method for preparing ultra-high purity carbonyl sulphur. The method comprises the following steps: S1. removing metal ions and moisture impurities from industrial carbonyl sulphur after vaporization; S2. performing several times of rectification on the carbonyl sulphur after the impurities are removed; the rectification process comprises at least one step of removing heavy components and at least one step of removing light components; S3. obtaining ultra-high purity carbonyl sulphur after removing water and oxygen impurities from the carbonyl sulphur after the rectification; In step S1, the metal ion removal process uses a mixture of hyper-crosslinked polystyrene macroporous adsorption resin and complex adsorption resin, and the moisture removal process uses a molecular sieve; 2. The process according to claim 1, characterized in that, In step S4, the water and oxygen impurity removal process uses a small-pore-size silicon-aluminum-silicate.

3. The process of claim 1, wherein, In step S2, the light components obtained at the end of the rectification process enter step S3. In step S2, the rectification process comprises three times, and the process is as follows: In the first rectification, heavy components are removed, and the light components are subjected to the second rectification; In the second rectification, light components are removed, and the heavy components are subjected to the third rectification; 4. The process of claim 3, wherein, In the third rectification, heavy components are removed, and the light components are obtained.

5. The process of claim 1, wherein, In step S2, in the rectification process: in the first rectification, the operating pressure is 0.8-1.8 MPa, the top temperature is 12-42 DEG C, and the bottom temperature is 13-45 DEG C; in the second rectification, the operating pressure is 0.7-1.7 MPa, the top temperature is 10-39 DEG C, and the bottom temperature is 12-42 DEG C; in the third rectification, the operating pressure is 0.4-1.5 MPa, the top temperature is -9-34 DEG C, and the bottom temperature is -7-32 DEG C.

6. The process of claim 1, wherein, In step S1, the impurity removal process reduces the iron ion impurities to below 100 ppb and reduces the moisture impurities to below 10 ppm; in step S3, the impurity removal process reduces the water and oxygen impurities to below 10 ppb respectively.

7. An apparatus for preparing ultra-high purity carbonyl sulfide from technical carbonyl sulfide, characterized by, The application also comprises a step of recovering the by-product carbonyl sulphur: the heavy components and the light components removed in the rectification process are compressed and condensed to obtain the recovered by-product carbonyl sulphur. The method comprises a pretreatment unit, a rectification unit and a post-treatment unit which are sequentially connected; The pretreatment unit is used for removing metal ions and moisture impurities; The rectification unit comprises several rectification towers which are sequentially connected and are used for removing heavy components at least once and removing light components at least once; The post-treatment unit is used for removing water and oxygen impurities; 8. The apparatus of claim 7, wherein, The pretreatment unit comprises a resin adsorber and a molecular sieve adsorber which are connected; the post-treatment unit comprises a purifier which is filled with small-pore-size silicon-aluminum-silicate; the resin adsorber is filled with a mixture of hyper-crosslinked polystyrene macroporous adsorption resin and complex adsorption resin.

9. The apparatus of claim 8, wherein, The rectification unit comprises a first rectification tower, a second rectification tower and a third rectification tower which are sequentially connected; the top of the first rectification tower is connected with the second rectification tower, the bottom of the second rectification tower is connected with the third rectification tower, and the top of the third rectification tower is connected with the post-treatment unit. The application also comprises a by-product recovery unit which comprises a compressor, a condenser and a storage tank which are sequentially connected; the input end of the compressor is connected with the bottom of the first rectification tower, the bottom of the second rectification tower and the top of the second rectification tower respectively, and the output end of the compressor is connected with the condenser.

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