Process for producing molybdenum dioxide dichloride

Abstract

The present invention relates to a process for producing molybdenum dioxide dichloride, which is a very efficient process that does not use hazardous chlorine gas and high reaction temperatures and enables the production of molybdenum dioxide dichloride in high yield without solvent.

Description

Technical Field

[0001] The present invention relates to a method for producing molybdenum dioxide dichloride (MoO2Cl2). More specifically, the present invention relates to a method for synthesizing molybdenum dioxide dichloride in an anhydrous and solvent-free form. Background Art

[0002] Molybdenum dioxide dichloride (MoO2Cl2) is a well-known molybdenum inorganic compound.

[0003] Recently, molybdenum dioxide dichloride (MoO2Cl2) has attracted much attention as a precursor for depositing metallic molybdenum films using vacuum deposition techniques (CVD or ALD) in the semiconductor industry.

[0004] Molybdenum films deposited using molybdenum dioxide dichloride (MoO2Cl2) generally exhibit better properties than those deposited using organometallic molybdenum precursors. This is because molybdenum dioxide dichloride (MoO2Cl2) does not contain nitrogen and carbon atoms, so the final film is purer.

[0005] Meanwhile, two common methods for synthesizing molybdenum dioxide dichloride (MoO2Cl2) are chlorination of molybdenum dioxide (MoO2) and molybdenum trioxide (MoO3), as shown in the following reaction formulas 1 and 2.

[0006] MoO2 + Cl2 → MoO2Cl2 (Reaction 1)

[0007] 2MoO3 + 2Cl2 → 2MoO2Cl2 + O2 (Equation 2)

[0008] The two methods of reaction formulas 1 and 2 are methods in which excess chlorine gas is passed through the solid oxide layers of molybdenum dioxide (MoO2) and molybdenum trioxide (MoO3) in reaction formulas 1 and 2 at high temperatures. The passage of chlorine gas is performed at a temperature above 200°C for the molybdenum dioxide layer and at a temperature above 900°C for the molybdenum trioxide layer.

[0009] Molybdenum dioxide dichloride (MoO 2 Cl 2 ) produced by the passage of chlorine gas in Reaction Formulas 1 and 2 is separated and obtained by sublimation.

[0010] However, the above two production methods according to Reaction Formulas 1 and 2 have problems as follows:

[0011] i) Excess chlorine used in the production process must be removed, and

[0012] ii) Molybdenum dioxide dichloride (MoO2Cl2) obtained by sublimation sublimes into a very light and fluffy solid which takes up collection space and has a high probability of clogging the exhaust line.

[0013] In order to solve the above problems, another method for producing molybdenum dioxide dichloride (MoO2Cl2) is proposed, as shown in the following reaction formulas 3-1 and 3-2.

[0014] Na2MoO4 + 4Me3SiCl(in dme) → MoO2Cl2(dme) + 2NaCl + 2(Me3Si)2O (Reaction 3-1)

[0015] (NH4)2Mo2O7 + 6Me3SiCl(in dme) → 2MoO2Cl2(dme) + 2NH4Cl + 3(Me3Si)2O (Reaction 3-2)

[0016] The production method according to reaction formulas 3-1 and 3-2 is to produce molybdenum dioxide dichloride solvate adduct (MoO2Cl2(dme)), which is a 1,2-dimethoxyethane (dme) solvated form of molybdenum dioxide dichloride, by reacting sodium molybdenum dioxide dichloride (Na2MoO4) and ammonium molybdate ((NH4)2Mo2O7) with chlorotrimethylsilanedimethoxyethane (Me3SiCl (in dme)).

[0017] The above two methods according to reaction formulas 3-1 and 3-2 can obtain pure molybdenum dioxide dimethoxyethane dichloride (MoO2Cl2(dme)) in high yield, and this product is widely used as an intermediate for synthesizing various molybdenum compounds.

[0018] It is known that the solvent of the above-mentioned solvated adduct can be removed by general techniques (such as heating in vacuum), but when the above-mentioned molybdenum dioxide dichloride dimethoxyethane (MoO2Cl2(dme)) is heated above its melting point, the molybdenum dioxide dichloride decomposes, making it impossible to obtain pure solvent-free molybdenum dioxide dichloride.

[0019] Another method for producing molybdenum dioxide dichloride (MoO2Cl2) is shown in Scheme 4 below.

[0020] MoOCl4 + (Me3Si)2O → MoO2Cl2 + 2Me3SiCl (Equation 4)

[0021] The fully chlorinated form of molybdenum oxytetrachloride (MoOCl4) is converted into the desired molybdenum dioxide dichloride (MoO2Cl2) in high yield by reaction with hexamethyldisiloxane. However, the starting material molybdenum oxytetrachloride (MoOCl4) in reaction formula 4 is not easy to obtain.

[0022] As described above, there are many problems in the production of molybdenum dioxide dichloride (MoO2Cl2), and it is urgent to develop a new method for producing molybdenum dioxide dichloride (MoO2Cl2) to improve these problems.

[0023] Public content

[0024] Technical issues

[0025] The present invention aims to provide a process for producing molybdenum dioxide dichloride (MoO2Cl2) which offers various advantages while overcoming the above-mentioned disadvantages of conventionally known production processes.

[0026] The present invention is also intended to achieve other objects, which can be easily obtained by those skilled in the art from the above-identified objects and the overall technology of this specification.

[0027] Technical Solution

[0028] The method for producing molybdenum dioxide dichloride (MoO2Cl2) according to the present invention can be expressed as shown in Reaction Formula 5.

[0029] MoO3 + SOCl2 → MoO2Cl2 + 2SO2 (Reaction 5)

[0030] Specifically, the method for producing molybdenum dioxide dichloride (MoO2Cl2) according to the present invention comprises:

[0031] i) a step of producing a mixture by mixing anhydrous molybdenum trioxide and thionyl chloride in a solvent under an inert gas (a first step of producing a mixture);

[0032] ii) a step of producing a solid product by precipitating the produced mixture by refluxing and stirring at an elevated temperature under an inert gas (a second step of producing a solid product); and

[0033] iii) a step of separating and purifying molybdenum dioxide dichloride (MoO2Cl2) from the produced solid product (the third step of separating and purifying molybdenum dioxide dichloride (MoO2Cl2)).

[0034] The details of the above steps are as follows:

[0035] In the first step of producing the mixture, molybdenum trioxide and thionyl chloride may be used in a ratio (by mole) of 1:0.5 to 1:2.0.

[0036] The solvent in the first step of producing the mixture must be a non-coordinating solvent that should not react or coordinate with the product molybdenum dioxide dichloride (MoO2Cl2).

[0037] Specifically, the non-coordinating solvent may be an aliphatic or aromatic solvent containing a halogen element and having 2 or more carbon atoms.

[0038] The solvent may have a boiling point of 50°C to 200°C.

[0039] The inert gas in the reaction vessels in the first step of producing a mixture and the second step of producing a solid product may be at least one gas selected from the group consisting of nitrogen (N2), argon (Ar) and helium (He).

[0040] In the second step of producing a solid product, the elevated temperature for reflux stirring may be 50°C to 200°C.

[0041] In the third step of separating and purifying molybdenum dioxide dichloride (MoO2Cl2), the separation is a step of filtering the produced solid product, washing it with the solvent of the first step of producing the mixture, and drying it in a vacuum to obtain molybdenum dioxide dichloride (MoO2Cl2).

[0042] The purification is carried out by subliming the dried molybdenum dioxide dichloride (MoO2Cl2).

[0043] Beneficial effects

[0044] As described above, the method for producing molybdenum dioxide dichloride (MoO2Cl2) according to the present invention is different from conventionally known technologies, has the advantages of being able to avoid dangerous chlorine gas and high reaction temperature, and obtains molybdenum dioxide dichloride (MoO2Cl2) in high yield without a solvent.

[0045] Furthermore, the method for producing molybdenum dioxide dichloride (MoO 2 Cl 2 ) according to the present invention has a safety advantage since it does not use dangerous chlorine gas and high reaction temperature, and thus is capable of both large-scale and small-scale production.

[0046] In addition, since readily available and inexpensive molybdenum trioxide (MoO3) and thionyl chloride (SOCl2) are used as reactants, there is an economic advantage in producing molybdenum dioxide dichloride (MoO2Cl2). BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 2 is a graph showing TGA (thermogravimetric analyzer) analysis results on purified molybdenum dioxide dichloride (MoO 2 Cl 2 ) obtained according to the first embodiment of the present invention (Embodiment 1) and molybdenum dioxide dichloride (MoO 2 Cl 2 ) purchased from Sigma Aldrich (reference).

[0048] Figure 21 is a graph showing the analysis results of ICP-MS (Inductively Coupled Plasma Mass Spectrometry) of sublimed molybdenum dioxide dichloride (MoO 2 Cl 2 ) according to the present invention.

[0049] Best Mode for Carrying Out the Invention

[0050] Hereinafter, the present invention will be described in detail.

[0051] The following description is merely an example of a specific embodiment. Since the present invention can be modified in various ways and can have various forms, the present invention is not limited to the specific embodiments described. It should be understood that the present invention includes all modifications, equivalents, or substitutes included in the spirit and technical scope of the present invention.

[0052] Furthermore, many specific details are described in the following description, such as specific components, but these are provided only to help provide a more general understanding of the present invention, and it is obvious to one skilled in the art that the present invention can be practiced without these specific details.

[0053] Furthermore, in the description of the present invention, if it is determined that a detailed description of related known functions or components may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted.

[0054] In addition, the terms used herein are only used to describe specific embodiments and are not intended to limit the present invention. Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention belongs. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and unless clearly defined in this application, shall not be interpreted in an idealized or overly formal sense.

[0055] In this specification, unless the context clearly indicates otherwise, a singular expression also includes a plural expression.

[0056] In this specification, the terms used to describe various components are not intended to limit the components. These terms are only used to distinguish one component from another.

[0057] In this specification, the terms "comprising", "including", "having" and the like are intended to specify the presence of the features, elements (or components) described herein, and do not mean that one or more other features or elements do not exist or cannot be added.

[0058] Hereinafter, the present invention will be described in detail.

[0059] The method for producing molybdenum dioxide dichloride (MoO2Cl2) according to the present invention can be expressed as shown in Reaction Formula 5.

[0060] MoO3 + SOCl2 → MoO2Cl2 + 2SO2 (Reaction 5)

[0061] Specifically, the method for producing molybdenum dioxide dichloride (MoO2Cl2) according to the present invention comprises:

[0062] i) a step of producing a mixture by mixing anhydrous molybdenum trioxide and thionyl chloride in a solvent under an inert gas (a first step of producing a mixture);

[0063] ii) a step of producing a solid product by precipitating the produced mixture by refluxing and stirring at an elevated temperature under an inert gas (a second step of producing a solid product); and

[0064] iii) a step of separating and purifying molybdenum dioxide dichloride (MoO2Cl2) from the produced solid product (the third step of separating and purifying molybdenum dioxide dichloride (MoO2Cl2)).

[0065] The details of the above steps are as follows:

[0066] In the first step of producing the mixture, molybdenum trioxide and thionyl chloride may be used in a ratio (by mole) of 1:0.5 to 1:2.0, preferably 1:0.8 to 1:1.5, and more preferably 1:1.

[0067] The solvent in the first step of producing the mixture must be a non-coordinating solvent that should not react or coordinate with the product molybdenum dioxide dichloride (MoO2Cl2).

[0068] Specifically, the non-coordinating solvent may be an aliphatic or aromatic solvent containing a halogen element and having 2 or more carbon atoms.

[0069] The solvent may have a boiling point of 50°C to 200°C, preferably 70°C to 120°C, and most preferably 80°C to 100°C.

[0070] Specifically, the solvent may be at least one solvent selected from the group consisting of tetrachloromethane (CCl4), 1,2-dichloroethane (C2H4Cl2), 1,1,1-trichloroethane, 1,1,2-trichloroethane (C2H3Cl3) and chlorobenzene (C6H5Cl).

[0071] The inert gas in the reaction vessels in the first step of producing a mixture and the second step of producing a solid product may be at least one gas selected from the group consisting of nitrogen (N2), argon (Ar) and helium (He).

[0072] In the second step of producing a solid product, the temperature increase for reflux stirring may be 50 to 200° C., preferably 70 to 120° C., more preferably 80 to 100° C. The reaction time for reflux stirring may be 16 to 72 hours.

[0073] In the third step of separating and purifying molybdenum dioxide dichloride (MoO2Cl2), the separation is a step of filtering the produced solid product, washing it with the solvent of the first step of producing the mixture, and drying it in a vacuum to obtain molybdenum dioxide dichloride (MoO2Cl2).

[0074] The purification is carried out by subliming the molybdenum dioxide dichloride (MoO2Cl2) obtained by drying.

[0075] Modes for Carrying Out the Invention

[0076] The present invention will be described more specifically by way of the embodiments given below.

[0077] <Implementation Plan 1>

[0078] Under an inert gas atmosphere, 100 g (0.68 mol) of anhydrous molybdenum trioxide was added to a 1 L 4-necked flask equipped with a magnetic stirrer. 500 ml of anhydrous 1,2-dichloroethane was added, and then 82 g (0.68 mol) of thionyl chloride was slowly added at room temperature to produce a mixture (MoO3:SOCl2 = 1:1 molar ratio).

[0079] The resulting mixture was stirred using a magnetic stirrer to form a white suspension. The suspension was stirred at reflux under an inert gas atmosphere for 24 hours while the temperature was increased. During this time, a clear change in the formation of a precipitate occurred.

[0080] The resulting yellow-brown mixture was filtered to obtain a yellow-brown solid product, which was washed with anhydrous 1,2-dichloroethane and dried under vacuum at room temperature to obtain 127 g of molybdenum dioxide dichloride (MoO 2 Cl 2 ) (yield 97%).

[0081] The obtained product (MoO2Cl2) was purified by sublimation (90°C / 180 mtorr) to obtain 121 g of light yellow solid product (yield 87%).

[0082] The yellow solid product (MoO2Cl2) was analyzed by TGA analysis. The TGA analysis results were consistent with the analysis results of molybdenum dioxide dichloride (MoO2Cl2, CAS No. 13637-68-8) purchased from SigmaAldrich. The results showed that the compound produced by the method for producing molybdenum dioxide dichloride according to the present invention was molybdenum dioxide dichloride (see Figure 1 ).

[0083] TGA analysis was performed using a Mettler Toledo TGA / DSC 3+. The test material was heated to 500°C at a rate of 10°C / min.

[0084] In addition, the yellow solid product (MoO2Cl2) obtained was shown to have a purity of more than 99.999% by ICP-MS analysis. Figure 2 ).

[0085] ICP-MS analysis was performed using a Thermo Scientific XSeries 2.

[0086] <Implementation Plan 2>

[0087] Except using 10 g (0.068 mol) of anhydrous molybdenum trioxide, 50 ml of anhydrous 1,2-dichloroethane and 7.4 g (0.063 mol) of thionyl chloride (MoO3:SOCl2 molar ratio = 1:0.9), 12 g of molybdenum dioxide dichloride (MoO2Cl2) (yield 87%) was obtained. The obtained molybdenum dioxide dichloride (MoO2Cl2) was purified by sublimation in the same manner as in Embodiment 1 to obtain 11 g of a light yellow solid product (MoO2Cl2) (yield 79%).

[0088] <Implementation Plan 3>

[0089] Except using 10 g (0.068 mol) of anhydrous molybdenum trioxide, 50 ml of anhydrous 1,2-dichloroethane and 9.9 g (0.083 mol) of thionyl chloride (MoO3:SOCl2 molar ratio = 1:1.2), 11 g of molybdenum dioxide dichloride (MoO2Cl2) (yield 82%) was obtained. The obtained molybdenum dioxide dichloride (MoO2Cl2) was purified by sublimation in the same manner as in Embodiment 1 to obtain 9 g of a light yellow solid product (MoO2Cl2) (yield 69%).

[0090] <Implementation Plan 4>

[0091] Synthesis was performed using the same method as in Example 1, using 10 g (0.068 mol) of anhydrous molybdenum trioxide, 50 ml of anhydrous 1,2-dichloroethane, and 8.2 g (0.069 mol) of thionyl chloride, stirred under reflux for 16 hours. (MoO3:SOCl2 = 1:1) 10 g of molybdenum dioxide dichloride was obtained with a yield of 72% before purification, and 9 g of a pale yellow solid product was obtained with a yield of 68% after purification.

[0092] <Implementation Plan 5>

[0093] The synthesis was carried out using the same method as in Embodiment 1, using 10 g (0.068 mol) of anhydrous molybdenum trioxide, 50 ml of anhydrous 1,2-dichloroethane, and 8.2 g (0.069 mol) of thionyl chloride, stirred at 60° C. for 24 hours. (MoO 3 : SOCl 2 = 1:1) 10 g of molybdenum dioxide dichloride was obtained with a yield of 76% before purification, and 7 g of a light yellow solid product was obtained with a yield of 49% after purification.

[0094] <Comparative Example 1>

[0095] The synthesis was carried out in the same manner as in Example 1, using 10 g (0.068 mol) of anhydrous molybdenum trioxide, 50 ml of anhydrous heptane, and 8.2 g (0.069 mol) of thionyl chloride, and stirring under reflux for 24 hours. However, the desired molybdenum dioxide dichloride was not obtained.

[0096] <Comparative Example 2>

[0097] The synthesis was carried out in the same manner as in Example 1, using 10 g (0.068 mol) of anhydrous molybdenum trioxide, 50 ml of anhydrous dichloromethane, and 8.2 g (0.069 mol) of thionyl chloride, and stirring under reflux for 24 hours. However, the desired molybdenum dioxide dichloride was not obtained.

[0098] <Comparative Example 3>

[0099] The synthesis was carried out in the same manner as in Example 1, using 10 g (0.068 mol) of anhydrous molybdenum trioxide, 50 ml of anhydrous toluene, and 8.2 g (0.069 mol) of thionyl chloride, and stirring under reflux for 24 hours. However, the desired molybdenum dioxide dichloride was not obtained.

[0100] <Comparative Example 4>

[0101] Synthesis was performed using the same method as in Example 1, using 10 g (0.068 mol) of anhydrous molybdenum trioxide, 50 ml of anhydrous 1,2-dichloroethane, and 16.4 g (0.136 mol) of thionyl chloride (MoO3:SOCl2 = 1:2 molar ratio) under reflux and stirring for 24 hours. However, the desired molybdenum dioxide dichloride was not obtained.

[0102] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above specific embodiments, and those skilled in the art can make various modifications without departing from the subject matter of the present invention. Therefore, the scope of the present invention should not be interpreted as being limited to the above embodiments, but should be determined not only by the claims given below, but also by the equivalents of the claims.

[0103] Industrial Applicability

[0104] As described above, the method for producing molybdenum dioxide dichloride (MoO2Cl2) according to the present invention is safe because chlorine gas and high reaction temperature are not used, and thus it can be produced not only on a small scale but also on a large scale, making it very useful industrially.

Claims

1. A method for producing molybdenum dioxide dichloride (MoO2Cl2), comprising: i) a step of producing a mixture by mixing anhydrous molybdenum trioxide and thionyl chloride in a non-coordinating solvent under an inert gas (a first step of producing a mixture); ii) a step of producing a solid product by precipitating the produced mixture by refluxing and stirring at an elevated temperature under an inert gas (a second step of producing a solid product); and iii) a step of separating and purifying molybdenum dioxide dichloride (MoO2Cl2) from the produced solid product (the third step of separating and purifying molybdenum dioxide dichloride (MoO2Cl2)), The solvent is an aliphatic or aromatic solvent having 2 or more carbon atoms and containing a halogen element and having a boiling point of 50° C. to 200° C.

2. The method according to claim 1, wherein the non-coordinating solvent is at least one non-coordinating solvent selected from the group consisting of tetrachloromethane (CCl4), 1,2-dichloroethane (C2H4Cl2), 1,1,1-trichloroethane, 1,1,2-trichloroethane (C2H3Cl3) and chlorobenzene (C6H5Cl).

3. The method according to claim 1, wherein in the first step of producing the mixture, molybdenum trioxide and thionyl chloride are used in a ratio (by mole) of 1:0.5 to 1:2.

0.

4. The method according to claim 1, wherein in the first step of producing the mixture, molybdenum trioxide and thionyl chloride are used in a ratio (by mole) of 1:0.8 to 1:1.

5.

5. The method according to claim 1, wherein in the first step of producing the mixture, molybdenum trioxide and thionyl chloride are used in a ratio (by mole) of 1:

1.

6. The method according to claim 1, wherein in the second step of producing a solid product, reflux stirring is performed at a temperature of 50°C to 200°C.

7. The method according to claim 1, wherein in the second step of producing a solid product, reflux stirring is performed at a temperature of 70°C to 120°C.

8. The method according to claim 1, wherein in the second step of producing a solid product, reflux stirring is performed at a temperature of 80 to 100°C.

9. The method according to claim 1, wherein the inert gas in the reaction vessels in the first step of producing a mixture and the second step of producing a solid product is at least one gas selected from the group consisting of nitrogen (N2), argon (Ar) and helium (He).

10. The method according to claim 1, wherein the reaction time of reflux stirring is 16 hours to 72 hours.

11. The method according to claim 1, wherein in the third step of separating and purifying molybdenum dioxide dichloride (MoO2Cl2), the purification is a sublimation method.

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