KR102622441B1 - New synthetic method of the sulfide-carbonyl (COS) in accordance with the amount of sulfur - Google Patents

Abstract

The present invention relates to a synthesis method and synthesis reaction apparatus for carbonyl sulfide (COS), which is used as a main raw material for pesticides, medicines, and various chemical products, and has recently attracted attention as a new etching gas material in the semiconductor manufacturing process.

Description

New synthetic method of the sulfide-carbonyl (COS) in accordance with the amount of sulfur}

The present invention relates to a synthesis method and synthesis reaction apparatus for carbonyl sulfide (COS), which is used as a main raw material for pesticides, medicines, and various chemical products, and has recently attracted attention as a new etching gas material in the semiconductor manufacturing process.

Specifically, in the synthesis of carbonyl sulfide by the gas-liquid contact method of sulfur and carbon monoxide gas in the reactor, the amount of sulfur supplied to the reactor is adjusted to produce carbonyl sulfide (COS) in a high yield of more than 90% without any other by-products. It relates to a method for synthesizing carbonyl sulfide (COS).

Carbonyl sulfide (COS) is a compound with a molecular structure of two double bonds and is used in various chemical products.

In particular, when etching is performed using CF-based gas and carbonyl sulfide (COS) together in the etching process of the semiconductor manufacturing process, the performance characteristics of the etching profile improvement and selectivity are excellent, and semiconductors such as DRAM and V-NAND are improved. The demand for carbonyl sulfide (COS) gas in processing is increasing.

Carbonyl sulfide (COS) is usually manufactured using carbon monoxide and sulfur as raw materials.

There are methods for synthesizing carbonyl sulfide using carbon monoxide and sulfur as raw materials, using catalysts.

For example, there are known methods of producing carbonyl sulfide in high yield through the gas phase reaction of carbon monoxide and sulfur using sulfur-containing metal compounds such as zinc sulfide, cadmium sulfide, lead sulfide, etc. as catalysts (US No. 2,983,580). .

However, when synthesizing carbonyl sulfide using this method, although the yield of carbonyl sulfide can be increased to over 90%, not only must the catalyst be periodically regenerated or replaced, but also side products due to impurities contained in the catalyst. There is a disadvantage in that the generation of unwanted by-products, such as hydrogen sulfide (H ₂ S), cannot be avoided.

Another method is to heat the supplied sulfur into a gas, mix the gaseous sulfur and carbon monoxide to create a mixed gas, and supply the mixed gas to a reactor to synthesize carbonyl sulfide (US No. 4,078,045). ).

This method proposes a technology for synthesizing carbonyl sulfide in high yield without using a catalyst, but includes a raw material mixing device for heating sulfur to form gas and mixing the sulfur gas with carbon monoxide gas, and the sulfur gas. A separate reaction device is required to receive and react the mixed gas of carbon monoxide and carbon monoxide, which is undesirable from an economic standpoint due to the equipment burden and the need for high energy to maintain the temperature of each separate device, and increases the manufacturing cost. becomes a factor.

In addition, when mixing carbon monoxide gas and gaseous sulfur to create a mixed gas, it is necessary to maintain a constant ratio of carbon monoxide and sulfur in order to obtain a high yield of carbonyl sulfide, but it is necessary to evaporate sulfur and mix it with carbon monoxide at a constant ratio. The technology poses significant practical challenges.

Another method is to produce carbonyl sulfide by bubbling carbon monoxide gas into liquid sulfur (KR 10-0938435), and in this method, there is no description of the amount of sulfur, the main raw material, used. Sulfur is the raw material that accounts for the most cost in the production of carbonyl sulfide.

In the above-described prior art, which does not limit the amount of sulfur used, the economic feasibility of the carbonyl sulfide process may be a problem due to the cost of a large amount of sulfur and the cost of liquefying a large amount of sulfur.

Therefore, there is a need for a new method that can produce carbonyl sulfide in large quantities economically and technically conveniently, whose importance is increasing with the development of the semiconductor industry.

Patent Document 1: US No. 2,983,580 Patent Document 2: US No. 4,078,045 Patent Document 3: KR No. 10-0938435

The present invention is intended to solve the problems of the prior art in synthesizing carbonyl sulfide using carbon monoxide and sulfur as raw materials and to provide a method for synthesizing carbonyl sulfide that is economical and technically convenient in terms of the process.

The purpose of the present invention is to provide a method for synthesizing carbonyl sulfide that is economical, simple, and efficient in the process through a non-catalytic reaction and a reaction between gaseous carbon monoxide and liquid sulfur.

Another object of the present invention is to provide a method for synthesizing carbonyl sulfide by supplying carbon monoxide gas into the interior of sulfur filled in a specific amount in a reactor to obtain a synthesis result containing only 90% or more of carbonyl sulfide and the remaining unreacted carbon monoxide. This is what I want to do.

According to this synthesis method, only unreacted carbon monoxide exists as a by-product, making it easy to purify the synthesized carbonyl sulfide, and the separated unreacted carbon monoxide can be reintroduced into the process. A method for synthesizing carbonyl sulfide and the same. The goal is to provide a reaction device.

The method for synthesizing carbonyl sulfide of the present invention to achieve this purpose is to first supply carbon monoxide gas to liquid sulfur stored inside a reactor capable of controlling pressure and temperature to react by a gas-liquid contact method.

By supplying carbon monoxide gas to such liquid sulfur and synthesizing carbonyl sulfide through a gas-liquid contact method, maintenance problems caused by regeneration and replacement of catalysts due to the use of catalysts in the prior art and generation of by-products due to impurities are prevented. did.

The temperature of the sulfur inside the reactor is maintained at 350-600°C by a heating means, and the amount of liquid sulfur filled inside the reactor is maintained at 10 to 40% by volume of the internal volume of the reactor to react carbon monoxide gas with the liquid sulfur. to synthesize carbonyl sulfide.

For gas-liquid contact by the liquid sulfur and carbon monoxide gas, carbon monoxide gas is supplied into the liquid sulfur.

The carbon monoxide gas is preferably supplied in a manner that it bubbles into the liquid sulfur.

Under the above conditions, after the synthesis of COS by the reaction of sulfur and carbon monoxide gas, the sulfur entrained with COS and vaporized by the boiling point is liquefied in a sulfur condenser kept cooled at 100°C to 200°C and introduced back into the reactor.

The carbonyl sulfide synthesis reaction device of the present invention as described above, which synthesizes carbonyl sulfide (COS) by reacting carbon monoxide (CO) gas with liquid sulfur (S),

A reactor (4) having an internal space to store liquid sulfur (S), equipped with a heating means, capable of controlling the temperature, and controlling the pressure if necessary;

Reactor heating means (4a) involved in controlling the temperature of the reactor;

A sulfur supply pipe (1) that supplies sulfur to the reactor;

A carbon monoxide gas supply pipe (3) installed to supply carbon monoxide (CO) gas into the liquid sulfur (S) stored in the internal space of the reactor;

A dip nozzle (3b) installed at the extreme end of the carbon monoxide gas supply pipe;

A nitrogen supply pipe (2) used to liquefy sulfur supplied to the reactor and/or remove impurities;

Heating means (3a) for preheating the gases when supplying the nitrogen and carbon monoxide gas;

After the carbonyl sulfide synthesis reaction in the reactor, a sulfur condenser (5) for controlling vaporized and entrained sulfur discharged together with the product carbonyl sulfide;

a sulfur cooler (5a) that lowers the temperature of the sulfur condenser;

Carbonyl sulfide discharge pipe (6) for discharging carbonyl sulfide synthesized in the reactor; and

It includes an internal temperature sensor (7) and an internal pressure sensor (8) to check the temperature and pressure inside the reactor.

According to the method of the present invention, the present invention has the feature of being able to continuously synthesize useful carbonyl sulfide gas economically and with high efficiency using a simple synthesis reaction device.

As described above, the method for synthesizing carbonyl sulfide according to the present invention, unlike previous technologies, does not use a catalyst, so it can suppress the decrease in catalyst activity or the production of by-products due to impurities contained in the catalyst, and can suppress the production of by-products due to impurities contained in the catalyst. Compared to the gas phase reaction where carbon monoxide reacts with gaseous sulfur, the reaction occurs at a significantly lower temperature, thus lowering the energy cost due to the high temperature reaction. By preventing decomposition of the reaction product, it is possible to produce carbonyl sulfide economically and in high yield. There is a characteristic.

In addition, when the amount of sulfur inside the reactor is between 10 and 40% by volume of the internal volume of the reactor, a high reaction efficiency of more than 90% is achieved. In particular, 90% of the reaction efficiency is all generated carbonyl sulfide, and the remaining 10% is carbonyl sulfide. As carbon monoxide reacts, no other side products are produced. Therefore, there is an advantage that the produced carbonyl sulfide can be easily purified.

In addition, the unreacted carbon monoxide separated by the purification of carbonyl sulfide can be reused in the carbonyl sulfide manufacturing process, thereby providing an economical effect in the process due to reduction of raw materials.

Regarding the manufacturing device, in the conventional technology for the reaction of gaseous carbon monoxide and sulfur, a mixing device for the two gases and a reactor in which the reaction occurs after mixing are essential, but in the present invention, the reaction is performed simply by supplying carbon monoxide gas to the liquid sulfur in the reactor. Since this is achieved, there is no need for manipulation to adjust the mixing ratio of the two raw materials, so the process is simple and has the advantage of being able to mass-produce through continuous operation.

In addition, it has the advantage of controlling the temperature of the reactor by supplying preheated nitrogen to liquefy the sulfur supplied to the reactor and/or remove impurities.

In addition, the sulfur accompanying vaporization and droplets discharged together with the produced carbonyl sulfide is controlled to a liquid state and reused in the reactor, thereby providing an economical effect in the process through reduction of raw materials.

Figure 1 schematically shows the production equipment used in the production process of carbonyl sulfide of the present invention.

Terms or words used in this specification and claims should not be construed as limited to their common or dictionary meanings, and the inventor may appropriately define the concept of terms in order to explain his or her invention in the best way. It must be interpreted with meaning and concept consistent with the technical idea of the present invention based on the principle that it is.

Accordingly, the embodiments described in this specification and the configurations shown in the drawings are only one of the most preferred embodiments of the present invention and do not represent the entire technical idea of the present invention, so at the time of filing this application, various alternatives are available to replace them. It should be understood that equivalents and variations may exist.

Hereinafter, the method and apparatus for synthesizing carbonyl sulfide of the present invention will be described in detail.

The method for synthesizing carbonyl sulfide of the present invention involves bubbling carbon monoxide gas supplied through a carbon monoxide gas supply pipe installed to be submerged in the sulfur liquid in a reactor containing liquid sulfur, thereby forming a gas-liquid relationship between sulfur and the supplied carbon monoxide gas in the sulfur liquid. The aim is to provide a new method for synthesizing carbonyl sulfide through contact without the need for a separate mixing device or catalyst.

The present invention has conducted research to develop a technology that can easily and economically produce carbonyl sulfide, which has expanded utility, with higher purity, and by adjusting the amount of liquid sulfur charged inside the reactor, at a pressure of 1 barg or more, especially The present invention was completed after discovering that carbonyl sulfide could be easily synthesized with a high yield of 90% or more even in a high-pressure reaction of 6 barg or more.

The method for synthesizing carbonyl sulfide according to the present invention is:

a) preparing liquid sulfur by dissolving solid sulfur and removing sulfur impurities;

b) a reaction step in which a gas-liquid reaction occurs by supplying and bubbling carbon monoxide gas to the liquid sulfur of process a).

Looking specifically at step a), the liquefaction of sulfur can be liquefied outside the reactor and then supplied to the reactor, or solid sulfur can be supplied to the reactor to proceed with liquefaction inside the reactor.

When liquefied outside the reactor and then supplied to the reactor, the reactor can be filled in a continuous or batch manner.

Solid sulfur supplied for liquefaction inside the reactor may be in a solid state such as powder, granule, or pellet.

When supplying the liquid and solid sulfur, it is preferable to use it after removing moisture in order to minimize by-products.

The solid sulfur supplied into the reactor can be liquefied using a heating means provided outside the reactor. At this time, nitrogen preheated from the outside can be supplied into the sulfur, and the preheated nitrogen contributes to the liquefaction of sulfur inside the sulfur and also serves to remove impurities contained in the sulfur.

Specifically, regarding the liquefaction of sulfur inside the reactor, powdered sulfur is charged into the reactor (4), where the temperature and pressure can be adjusted as needed, through the sulfur supply pipe (1), and then the reactor is heated to about 100-200°C. While maintaining heating, nitrogen is supplied through the nitrogen supply pipe (2) at 10 to 50 mL/min, preferably 30 mL/min, and the sulfur is melted using the reactor heating means (4a) to liquefy the sulfur inside the reactor. Fill with more than 10 and less than 40 (volume %) of the internal volume.

At this time, the nitrogen is preheated to 100-200°C, preferably 150°C, and supplied to the sulfur in the reactor through the dip nozzle (3b). The nitrogen is preheated using a heating means (3a).

The reactor temperature is maintained at 300-600°C, and a certain amount of sulfur inside the reactor is 10% to 40% of the internal volume of the reactor.

When liquid sulfur is prepared in the reactor of step a) as above, the synthesis of carbonyl sulfide proceeds as in step b) below.

Step b) is a step in which carbonyl sulfide is synthesized through a gas-liquid reaction of liquid sulfur and carbon monoxide gas.

The supply of nitrogen (N ₂ ) is stopped in the reactor (4) in which liquid sulfur is stored at a certain amount, that is, 10 to 40 (volume %) of the internal volume of the reactor, and carbon monoxide (CO) gas is supplied through the supply pipe (3). At this time, the temperature of the reactor 4 is 300 to 600°C, preferably 400 to 550°C, and more preferably 430 to 500°C.

Carbon monoxide gas supplied through the supply pipe 3 is supplied into liquid sulfur so that a gas-liquid contact reaction can occur.

At this time, if the range of liquid sulfur is less than 10% in the reactor, the reaction contact due to bubbles between liquid sulfur and carbon monoxide gas is lowered, lowering the production efficiency of carbonyl sulfide. Conversely, if it is more than 40%, the production of carbonyl sulfide in the reactor is reduced. As the partial pressure (space) for this decreases, the production efficiency of carbonyl sulfide also decreases (see Examples and FIG. 2).

The dip nozzle (3b), which is the end of the carbon monoxide gas supply pipe (3), may be at least 5 cm deep from the liquid sulfur interface (water surface) stored in the reactor (4).

If the immersion depth of the dip nozzle 3b is lower than the above 5 cm, sufficient contact does not occur between the carbon monoxide gas and liquid sulfur, which is not good because the amount of unreacted carbon monoxide increases.

At this time, the supply amount of carbon monoxide gas supplied to the liquid sulfur may be 0.7 L/min or less per 1 barg of reactor pressure.

Additionally, the supplied carbon monoxide gas may be preheated and supplied using the heating means 3a to a temperature lower than the reactor temperature below. The preheating temperature of the carbon monoxide gas may be 150 to 300°C, preferably 150 to 250°C, and more preferably 150 to 200°C.

The reaction temperature of the gas-liquid contact reaction between carbon monoxide and liquid sulfur is 350 to 600°C, preferably 400 to 550°C, and more preferably 430 to 500°C, as in the above reactor temperature.

The reaction pressure of the gas-liquid contact reaction between carbon monoxide and liquid sulfur is It can be more than 1 barg.

Under the conditions of the amount of sulfur in the reactor described above, carbon monoxide gas is supplied through the dip nozzle of the supply pipe submerged in liquid sulfur, making it possible to continuously produce carbonyl sulfide in high yield without a catalyst or a separate high-temperature gas phase reaction device. .

In order to increase gas-liquid contact efficiency, it is relatively more advantageous to use a vertical or column-type reactor rather than a horizontal type, but any type of reactor can be used as long as sufficient gas-liquid contact is achieved.

The reaction apparatus for synthesizing carbonyl sulfide of the present invention includes a reactor (4) in the form of a vertical cylinder as shown in Figure 1; Heating means (4a) for heating the reactor (4); A sulfur supply pipe (1) that supplies sulfur into the reactor (4); A nitrogen supply pipe (2) that supplies nitrogen into the reactor; A carbon monoxide gas supply pipe (3) that supplies carbon monoxide into the reactor (4); Heating means (3a) for preheating when supplying the nitrogen and carbon monoxide gases; A dip nozzle (3b) installed at the very end of the carbon monoxide gas supply pipe (3); A sulfur condenser (5) that condenses sulfur entrained in droplets together with the carbonyl sulfide synthesized by reaction in the reactor (4); A sulfur cooler (5a) that cools the sulfur condenser to 100-200°C, preferably 150°C; and a discharge pipe (6) for discharging the produced carbonyl sulfide.

The reactor (4) includes a water level gauge (not shown) capable of measuring the level of liquid sulfur; A temperature sensor (7) that measures the internal temperature; and a pressure sensor (8) that measures internal pressure.

The reaction pressure inside the reactor (4) is maintained constant by controlling the gas flow rate flowing out of the reactor (4) using a valve. That is, it is controlled using a valve installed in the discharge pipe (6) that discharges carbonyl sulfide.

The reactor 4, where carbonyl sulfide is synthesized from the sulfur and carbon monoxide gas, may be made of any material as long as it can withstand temperature and pressure, but copper-based metals should not be used as they are vulnerable to sulfur.

Since carbon steel or iron materials are easily oxidized and easily generate impurities such as rust, it is preferable to use stainless steel, nickel, or nickel alloy metal materials whenever possible.

Valves for controlling supply and discharge may be installed in the carbon monoxide gas supply pipe 3, the nitrogen supply pipe 2, the sulfur supply pipe 1, and the discharge pipe 6 for discharging carbonyl sulfide, respectively.

The heating means (3a, 4a) usually use electric heaters, and are involved in controlling the temperatures of nitrogen and carbon monoxide, and the temperature of the reactor, respectively.

The dip nozzle (3b) is installed at the end of the carbon monoxide supply pipe (the end of the pipe submerged in liquid), and can improve the gas-liquid contact effect and increase reaction efficiency by dispersing small bubbles of the supplied carbon monoxide. .

This dip nozzle 3b may be equipped with a bubbling device that helps disperse bubbles, such as a bubbler or sparger, or may be processed to facilitate bubble generation, and the pipe may be used as is. In other words, if the carbon monoxide supplied to the reactor is designed to be discharged within liquid sulfur, there are no restrictions on the shape of the pipe for supplying carbon monoxide gas.

In addition, a stirrer may be used to increase the contact efficiency between the supplied carbon monoxide gas and the sulfur liquid, but since high yields can be obtained without a separate stirrer, it may be advantageous to not have a stirrer in terms of economics and maintenance.

The sulfur condenser (5) is installed to control sulfur that is entrained in droplets along with vaporized sulfur discharged together with carbonyl sulfide after the carbonyl sulfide synthesis reaction, and the temperature is adjusted to 100°C to 200°C through the sulfur cooler (5a). It is preferably cooled to 150°C to liquefy the evaporated sulfur and the entrained sulfur and feed it back into the reactor, which serves to reduce the sulfur discharged.

The discharge pipe 6 is installed at the top of the reactor to discharge carbonyl sulfide produced through a synthesis reaction, and can also be used to analyze the yield of synthesized carbonyl sulfide.

In the following, the present invention will be described in more detail through examples.

The device used in the following examples is a 7L high-pressure reactor synthesis device (see Figure 1). The high-pressure reactor synthesis device includes a 7L reactor; Sulfur condenser; Supply pipes for supplying sulfur, carbon monoxide gas, and nitrogen in the reactor; 3 port type dip nozzle for supply of carbon monoxide gas and nitrogen; An electric furnace (Furance, corresponding to reference numeral 4a in FIG. 1) capable of controlling the temperature to maintain the reaction temperature of the reactor; etc., and the operating range of the reactor is 150°C to 600°C. In addition, in order to preheat the gas flow of the reactor, that is, when supplying carbon monoxide gas and nitrogen, the temperature of the tube through which carbon monoxide gas and nitrogen are supplied was maintained at 150 to 200°C using a heating jacket and heating band.

Sulfur accompanying the synthesized carbonyl sulfide is liquefied using a sulfur condenser located at the top of the reactor and reused in the reactor (4), so that only the synthesized carbonyl sulfide is in the discharge pipe (6). was allowed to be discharged. The yield of carbonyl sulfide was confirmed by sampling from the carbonyl sulfide outlet (6) using GC-TCD.

The carbon monoxide gas used was CO from Air Liquide.

Example

A 7L high-temperature high-pressure reactor equipped with a 10 cm dip nozzle (depth from the surface of liquid sulfur) for carbon monoxide gas supply was charged with solid sulfur to 5 to 55% of the internal volume of the high-pressure reactor, and then nitrogen was added at 50 mL/mL for 12 hr at about 150°C. min supply to remove the moisture inside the sulfur and change the solid sulfur into liquid sulfur. After removing moisture as described above, the reaction temperature of the reactor was increased to 450°C, and the carbon monoxide gas supply temperature was maintained at 170°C while the carbon monoxide flow rate was supplied at 4 L/min at a reaction pressure of 6 barg. It was measured using G.C., and the results are shown in Table 1 below.

Reactor charge (%) G.C. (%) C.O. _CO2 COS CS ₂ etc 5 16.43 - 83.57 - - 10 9.91 - 90.09 - - 15 8.05 - 91.95 - - 20 7.23 - 92.77 - - 25 6.23 - 93.77 - - 30 5.55 - 94.45 - - 35 4.10 - 95.90 - - 40 17.63 - 82.37 - - 45 27.48 - 72.52 - - 51 39.55 - 60.45 - - 55 42.70 - 57.30 - -

As shown in Table 1 of the above example, in the method for producing carbonyl sulfide of the present invention, the amount of sulfur in the reactor is set to 10 to 40 (volume %) of the internal volume of the reactor, and the synthesis of carbonyl sulfide is performed when reacting with carbon monoxide gas. It can be seen that the yield was over 90%, and the rest was all unreacted carbon monoxide gas.

The method for synthesizing carbonyl sulfide of the present invention can obtain carbonyl sulfide in a high yield of 90% or more even in a high pressure reaction of 1 barg or more, especially 6 barg or more, and contains only unreacted carbon monoxide gas as a by-product, thereby producing the above-described carbonyl sulfide. Carbonyl sulfide obtained by synthesis is easy to purify, which has the advantage of obtaining high purity carbonyl sulfide.

This high-purity carbonyl sulfide can be used in semiconductor manufacturing, so it has high industrial applicability.

Although the present invention has been described above using several preferred examples, these examples are illustrative and not limiting. As such, those of ordinary skill in the technical field to which the present invention pertains will understand that various changes and modifications can be made according to the theory of equivalents without departing from the spirit of the present invention and the scope of rights set forth in the appended claims.

1: Sulfur supply pipe
2: Nitrogen supply pipe
3: Carbon monoxide gas supply pipe
3a: Gas supply pipe heating means
4a: Reactor heating means
3b: Deep nozzle
4: reactor
5: Sulfur condenser
5a: sulfur cooler
6: Carbonyl sulfide discharge pipe
7: Reactor temperature sensor
8: Reactor pressure gauge

Claims (8)

Carbon monoxide gas is supplied while bubbling into liquid sulfur inside a reactor capable of controlling temperature and pressure, and carbonyl sulfide (COS) is synthesized through a gas-liquid contact reaction between carbon monoxide (CO) gas and liquid sulfur (S). As for how to do it,
The liquid sulfur inside the reactor is 10 to 40% of the internal volume of the reactor.
(volume %),
A method of synthesizing carbonyl sulfide, characterized in that the carbon monoxide (CO) gas supplied into the liquid sulfur inside the reactor is preheated to 100-200 ° C. The method of claim 1,
A method for synthesizing carbonyl sulfide, characterized in that the reaction temperature of the gas-liquid contact method of carbon monoxide (CO) gas and liquid sulfur (S) is 300 to 600 ° C. The method of claim 1,
The pressure of the reactor is 1 barg or more, and the supply of carbon monoxide (CO) gas is performed at a depth of 5 cm or more from the surface of the liquid sulfur inside the reactor. delete The method of claim 1,
A method for synthesizing carbonyl sulfide, characterized in that the liquid sulfur in the reactor is liquefied and impurities are removed by adding nitrogen while heating the solid sulfur supplied into the reactor. The method of claim 5,
A method for synthesizing carbonyl sulfide, characterized in that the nitrogen is supplied after being preheated to 100-200°C. delete delete