Iron-based catalyst for efficient synthesis of carbonyl sulfide and preparation method thereof

Abstract

The application discloses an iron-based catalyst for efficiently synthesizing carbonyl sulfur and a preparation method thereof. The iron-based catalyst is obtained by mixing inorganic iron salt, inorganic nickel salt, a template agent and urea, using a hydrothermal synthesis method and high-temperature calcination. In the process of calcination, the organic molecules in the precursor are decomposed at high temperature and discharged into the environment in the form of gas, promoting the formation of a pore structure of the catalyst. The synthesis method has simple synthesis conditions, rapid reaction, short time consumption, and the obtained catalyst has a carbonyl sulfur conversion rate as high as 100% at 450 DEG C, and is suitable for efficient production of carbonyl sulfur gas.

Description

Technical Field

[0001] This invention belongs to the field of inorganic material preparation, specifically relating to an iron-based catalyst for the efficient synthesis of carbonyl sulfide and its preparation method. Background Technology

[0002] Carbonyl sulfide can be used in carbonylation reactions. Carbonylation is a reaction that converts compounds such as alcohols, acids, aldehydes, and ketones into carbonyl compounds such as esters, acid anhydrides, and amides. Carbonyl sulfide can act as a catalyst in carbonylation reactions, promoting the reaction. Carbonyl sulfide-catalyzed carbonylation reactions have advantages such as mild reaction conditions, fast reaction rates, and high yields.

[0003] Carbonyl sulfide can be used in carbonyl addition reactions. A carbonyl addition reaction is a reaction in which a carbonyl compound reacts with a nucleophile (such as an alcohol, amine, or thiol) to form a new compound. Carbonyl sulfide can act as a reagent in carbonyl addition reactions, reacting with nucleophiles to form carbonyl thioesters, thioesters, and other compounds. Carbonyl thioesters and thioesters exhibit high reactivity and can further participate in other organic synthesis reactions.

[0004] Carbonyl sulfide can be used in carbonyl reduction reactions. A carbonyl reduction reaction is a reaction that reduces carbonyl compounds such as ketones and aldehydes to their corresponding alcohols. Carbonyl sulfide can act as a reducing agent in carbonyl reduction reactions, reducing carbonyl compounds to their corresponding alcohols. The reduction of carbonyl sulfide has advantages such as mild reaction conditions and high reduction efficiency.

[0005] Carbonyl sulfide can also be used in carbonyl activation reactions. Carbonyl activation reactions are reactions that convert carbonyl compounds into reactive intermediates. Carbonyl sulfide can act as a reagent in carbonyl activation reactions, converting carbonyl compounds into thiocarbonyl compounds. Thiocarbonyl compounds exhibit high reactivity and can further participate in other organic synthesis reactions.

[0006] Moreover, in recent years, electronic-grade carbonyl sulfur specialty gases have been widely used in semiconductor manufacturing processes, such as line detailing and etching, and are important auxiliary raw material gases in semiconductor manufacturing processes such as integrated circuits and chip manufacturing.

[0007] However, in the existing dry process for producing carbonyl sulfide, the high reaction temperature easily leads to many side reactions, resulting in low purity of the final carbonyl sulfide gas. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to provide a novel method for synthesizing iron-based catalysts. The synthesized iron-based catalysts have a carbonyl sulfide conversion rate of up to 100% at 450°C, which is suitable for the efficient production of carbonyl sulfide gas and can solve the problem of low carbonyl sulfide production capacity at present.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] An iron-based catalyst for the efficient synthesis of carbonyl sulfide is prepared by adding inorganic iron salt, inorganic nickel salt, template agent and urea into a polytetrafluoroethylene-lined reactor and stirring. Then, an alkaline liquid is added dropwise to adjust the pH value and stirring is continued until homogeneous. The mixture is then transferred to an oven for hydrothermal reaction. The reaction product is filtered and calcined to obtain the iron-based catalyst.

[0011] Furthermore, the inorganic iron salt is ferric sulfate pentahydrate, ferric nitrate nonahydrate, or ferric chloride hexahydrate.

[0012] Furthermore, the inorganic nickel salt is nickel sulfate hexahydrate, nickel nitrate hexahydrate, or nickel chloride hexahydrate.

[0013] Furthermore, the template agent is hexadecyltrimethylammonium bromide (CTAB).

[0014] Furthermore, the molar percentage ratio of the inorganic iron salt to the inorganic nickel salt used is 100:0-80:20.

[0015] Furthermore, based on the total molar amount of inorganic iron salt and inorganic nickel salt, 0-2 g of template agent and 0-1 g of urea are used per 10 mmol.

[0016] Furthermore, the alkaline liquid is ammonia water or NaOH solution.

[0017] Furthermore, the adjusted pH value is 8-11.

[0018] Furthermore, the hydrothermal reaction is carried out at a temperature of 80~180 ℃ for a time of 6~24 h.

[0019] Furthermore, the calcination temperature is 400~700 ℃, and the time is 1~10 h.

[0020] The obtained iron-based catalyst can be used for the efficient synthesis of carbonyl sulfide. Specifically, carbon monoxide and elemental sulfur vapor are used as raw material gases, and the iron-based catalyst is used for catalysis to achieve the synthesis of carbonyl sulfide.

[0021] Furthermore, the flow rate of both raw material gases was 50 mL / min, and the reaction temperature was 450~600 ℃.

[0022] The significant advantages of this invention are:

[0023] (1) The present invention uses a hydrothermal synthesis method, in which CTAB and urea are added to the system as template agents and pore-forming agents to form abundant mesopores; while the added base can be used to adjust the pH to control the type of interaction between the metal species and the template agent, thereby controlling the structural properties of the product (such as porous structure, crystal phase, morphology, etc.).

[0024] (2) The synthesis conditions of the method of the present invention are simple, the reaction is rapid, and the time consumption is short. Attached Figure Description

[0025] Figure 1 The XRD patterns of the iron-based catalysts prepared in Examples 1-4 and the comparative examples are shown below.

[0026] Figure 2 N2 adsorption-desorption curves (A) and pore size distribution diagrams (B) of the iron-based catalysts prepared in Examples 1-4 and comparative examples;

[0027] Figure 3 The image shows a SEM image of the iron-based catalyst prepared in Example 3. Detailed Implementation

[0028] An iron-based catalyst for the efficient synthesis of carbonyl sulfide is prepared by weighing inorganic iron salt and inorganic nickel salt in a molar percentage ratio of 100:0-80:20, and weighing out 0-2 g of template agent and 0-1 g of urea per 10 mmol of total metal salt. The mixture is added to a polytetrafluoroethylene-lined reactor and stirred. Then, an alkaline liquid is added dropwise to adjust the pH to 8-11, and stirring is continued until homogeneous. The mixture is then transferred to an oven and subjected to hydrothermal reaction at 80-180 °C for 6-24 h. The reaction product is filtered and calcined at 400-700 °C for 1-10 h to obtain a nickel-doped iron oxide catalyst.

[0029] The inorganic iron salt is ferric sulfate pentahydrate, ferric nitrate nonahydrate, or ferric chloride hexahydrate. The inorganic nickel salt is nickel sulfate hexahydrate, nickel nitrate hexahydrate, or nickel chloride hexahydrate. The template agent is hexadecyltrimethylammonium bromide (CTAB). The alkaline liquid is ammonia or NaOH solution.

[0030] To make the content of this invention easier to understand, the technical solution of this invention will be further described below with reference to specific embodiments, but this invention is not limited thereto.

[0031] Example 1:

[0032] 3.636 g (9 mmol) of ferric nitrate nonahydrate, 0.291 g (1 mmol) of nickel nitrate hexahydrate, 0.4 g of CTAB, and 0.1 g of urea were weighed and added to 100 mL of water. After mixing thoroughly, the pH was adjusted to 8 with ammonia, and stirring was continued. The mixture was then subjected to a hydrothermal reaction at 100 °C for 24 h. After the reaction was completed and cooled to room temperature, the mixture was filtered until neutral to obtain the initial product. The initial product was then calcined in a muffle furnace at 400 °C for 2 h. After natural cooling, a 10% nickel-doped iron oxide catalyst for the synthesis of carbonyl sulfide was obtained, denoted as catalyst A.

[0033] Example 2:

[0034] 3.920 g (8 mmol) of ferric sulfate pentahydrate, 0.526 g (2 mmol) of nickel sulfate hexahydrate, 1 g of CTAB, and 1 g of urea were weighed and added to 100 mL of water. After mixing thoroughly, the pH was adjusted to 11 with ammonia, and stirring was continued. The mixture was then subjected to a hydrothermal reaction at 140 °C for 16 h. After the reaction was completed and cooled to room temperature, the mixture was filtered until neutral to obtain the initial product. The initial product was then calcined in a muffle furnace at 600 °C for 6 h. After natural cooling, a 20% nickel-doped iron oxide catalyst for the synthesis of carbonyl sulfide was obtained, denoted as catalyst B.

[0035] Example 3:

[0036] 4.655 g (9.5 mmol) of ferric sulfate pentahydrate, 0.013 g (0.5 mmol) of nickel sulfate hexahydrate, 2 g of CTAB, and 0.5 g of urea were weighed and added to 100 mL of water. After mixing thoroughly, the pH was adjusted to 10 with ammonia, and stirring was continued. The mixture was then subjected to a hydrothermal reaction at 180 °C for 12 h. After the reaction was completed and cooled to room temperature, the mixture was filtered until neutral to obtain the initial product. The initial product was then calcined in a muffle furnace at 700 °C for 4 h. After natural cooling, a 5% nickel-doped iron oxide catalyst for the synthesis of carbonyl sulfide was obtained, denoted as catalyst C.

[0037] Example 4:

[0038] 2.433 g (9.9 mmol) of ferric chloride hexahydrate, 0.024 g (0.1 mmol) of nickel chloride hexahydrate, 1.5 g of CTAB, and 0.1 g of urea were weighed and added to 100 mL of water. After mixing thoroughly, the pH was adjusted to 9 with ammonia, and stirring was continued. The mixture was then subjected to a hydrothermal reaction at 180 °C for 12 h. After the reaction was completed and cooled to room temperature, the mixture was filtered until neutral to obtain the initial product. The initial product was then calcined in a muffle furnace at 550 °C for 8 h. After natural cooling, a 1% nickel-doped iron oxide catalyst for the synthesis of carbonyl sulfide was obtained, denoted as catalyst D.

[0039] Comparative example:

[0040] 4.04 g (10 mmol) of ferric nitrate nonahydrate, 1 g of CTAB, and 0.1 g of urea were weighed and added to 100 mL of water. After mixing thoroughly, the pH was adjusted to 8 with ammonia, and stirring was continued. The mixture was then subjected to a hydrothermal reaction at 80 °C for 6 h. After the reaction was completed and cooled to room temperature, the mixture was filtered until neutral to obtain the initial product. The initial product was then calcined in a muffle furnace at 600 °C for 5 h. After natural cooling, the iron oxide catalyst was obtained, denoted as catalyst E.

[0041] The obtained catalyst was analyzed and tested accordingly:

[0042] Figure 1 The XRD patterns of the iron-based catalysts prepared in Examples 1-4 and the comparative examples are shown in the figures. As can be seen from the figures, all five samples showed characteristic derived peaks of iron oxide at 24.2°, 33.2°, 35.7°, 40.9°, 49.5°, 54.1°, 62.5°, and 64.0°, indicating that nickel doping did not affect the crystal structure of α-Fe2O3.

[0043] Figure 2 The N2 physical adsorption-desorption isotherm (A) and pore size distribution diagram (B) of the catalyst prepared in Example 3 at liquid nitrogen temperature are shown. As can be seen from the figure, catalyst C contains not only a large number of mesopores, but also a certain amount of micropores.

[0044] Figure 3 The image shows a SEM image of the iron-based catalyst prepared in Example 3. As can be seen from the image, the synthesized nickel-doped iron oxide is composed of nanoparticles with uniform particle size, which is more conducive to gas adsorption and catalysis during the reaction.

[0045] The catalyst activity was expressed as carbonyl sulfide conversion and carbonyl sulfide selectivity, and the carbonyl sulfide concentration was tested using online chromatography. The test conditions were as follows: the activity test for synthesizing carbonyl sulfide was conducted in a fixed-bed quartz reactor. The catalyst loading was 0.2 g, with a height of approximately 1 cm and a particle size of 40–60 mesh. The reaction temperature was 450–600 °C. Samples were taken and measured after 1 h at each reaction temperature. The heating rate was 3 °C / min, and the temperature intervals were 20 °C. The reaction tube was a quartz tube with an inner diameter of 5 mm, and the flow rate of the feed gas (carbon monoxide and elemental sulfur vapor) was 50 mL / min. The test results are shown in Tables 1 and 2.

[0046] Table 1. Carbonyl sulfide conversion rates of different catalysts

[0047]

[0048] Table 2. Carbonyl sulfide selectivity of different catalysts

[0049]

[0050] As can be seen from Table 1, among the catalysts with different nickel doping amounts, catalyst C has significantly higher activity than A, B, and D. It has already achieved 100% carbonyl sulfide conversion at 450 °C, while the other catalysts can only achieve 100% conversion at reaction temperatures of 540 °C or higher. The undoped catalyst E has never achieved 100% conversion in the test temperature range.

[0051] As shown in Table 2, catalysts A, B, C, and D can all achieve 100% selectivity at 450 °C. However, as shown in Table 1, only catalyst C can achieve 100% conversion at this temperature, indicating that only the gaseous products of catalyst C have 100% purity. As the temperature continues to rise, all catalysts exhibit a decrease in selectivity.

[0052] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.

Claims

1. Use of an iron-based catalyst for the efficient synthesis of carbonyl sulphur, characterised in that: Carbon monoxide and elemental sulfur vapor are used as raw gas, and the iron-based catalyst is used for catalysis to realize synthesis of carbonyl sulfide; The iron-based catalyst is prepared by mixing inorganic iron salt, inorganic nickel salt, template agent and urea, then adding alkaline liquid to adjust pH value, and then stirring, followed by hydrothermal reaction, filtering and calcination; The molar percentage ratio of the inorganic iron salt to the inorganic nickel salt is 99:1-80:20; the template agent is CTAB; 0.4-2 g of template agent and 0.1-1 g of urea are used per 10 mmol of the total molar amount of the inorganic iron salt and the inorganic nickel salt; The adjusted pH value is 8-11; The temperature of the hydrothermal reaction is 80-180 ℃, and the time is 6-24 h; The temperature of the calcination is 400-700 ℃, and the time is 1-10 h.

2. Use according to claim 1, characterized in that: The inorganic iron salt is iron sulfate pentahydrate, iron nitrate nonahydrate or iron chloride hexahydrate; the inorganic nickel salt is nickel sulfate hexahydrate, nickel nitrate hexahydrate or nickel chloride hexahydrate.

3. Use according to claim 1, characterized in that: The alkaline liquid is ammonia water or NaOH solution.

4. Use according to claim 1, characterized in that: The flow rate of the two kinds of raw gas is 50 mL / min, and the reaction temperature is 450-600 ℃.

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