阅读说明：本技术 一种氮化硼负载铑镓锡液态合金催化剂及其制备方法和应用 (Boron nitride-loaded rhodium-gallium-tin liquid alloy catalyst and preparation method and application thereof ) 是由 李嵘嵘 韩得满 于 2020-04-23 设计创作，主要内容包括：本发明提供了一种氮化硼负载铑镓锡液态合金催化剂及其制备方法和应用,属于催化剂技术领域。本发明提供的氮化硼负载铑镓锡液态合金催化剂,包括氮化硼和负载在所述氮化硼表面的活性组分；所述活性组分包括铑镓锡液态合金。本发明以铑、镓和锡作为活性组分,以氮化硼作为载体,铑原子、镓原子和锡原子之间形成三金属的液态稳定结构,使铑、镓和锡不会发生团聚,分散性好；铑、镓和锡与氮化硼载体的结合力强,催化剂稳定性高；而且与负载贵金属(Pd、Ag、Au)相比催化剂的成本大大降低。(The invention provides a boron nitride loaded rhodium-gallium-tin liquid alloy catalyst, and a preparation method and application thereof, and belongs to the technical field of catalysts. The boron nitride loaded rhodium-gallium-tin liquid alloy catalyst provided by the invention comprises boron nitride and an active component loaded on the surface of the boron nitride; the active component includes a rhodium gallium tin liquid alloy. The invention takes rhodium, gallium and tin as active components, takes boron nitride as a carrier, and forms a liquid stable structure of three metals among rhodium atoms, gallium atoms and tin atoms, so that the rhodium, the gallium and the tin cannot be agglomerated and have good dispersibility; the bonding force of rhodium, gallium and tin with the boron nitride carrier is strong, and the stability of the catalyst is high; and compared with the catalyst loaded with noble metals (Pd, Ag and Au), the cost of the catalyst is greatly reduced.)

1. A boron nitride supported rhodium-gallium-tin liquid alloy catalyst comprises boron nitride and an active component supported on the surface of the boron nitride; the active component includes a rhodium gallium tin liquid alloy.

2. The boron nitride supported rhodium-gallium-tin liquid alloy catalyst according to claim 1, wherein the content of active components in the boron nitride supported rhodium-gallium-tin liquid alloy catalyst is 0.8-8.5 wt%.

3. A method for preparing the boron nitride supported rhodium-gallium-tin liquid alloy catalyst as claimed in claim 1 or 2, characterized by comprising the following steps:

mixing a water-soluble rhodium source, a water-soluble gallium source, a water-soluble tin source and water, mixing the obtained mixed solution with boron nitride, standing, dipping and drying to obtain a catalyst precursor;

and sequentially carrying out calcination and reduction reaction on the catalyst precursor to obtain the boron nitride loaded rhodium-gallium-tin liquid alloy catalyst.

4. The preparation method according to claim 3, wherein the mass of the water-soluble rhodium source, the mass of the water-soluble gallium source and the mass of the water-soluble tin source are calculated according to the mass of rhodium, gallium and tin respectively, and the mass ratio of the water-soluble rhodium source to the water-soluble gallium source to the water-soluble tin source to boron nitride is 0.002-0.015: 0.003 to 0.04: 0.003 to 0.04: 1.

5. a method of manufacture as claimed in claim 3 or claim 4 wherein the water soluble source of rhodium comprises rhodium chloride, rhodium nitrate, ammonium chlororhodate, rhodium sulphate, potassium hexachlororhodium (III) or rhodium (III) triacetylacetonate.

6. The production method according to claim 3 or 4, characterized in that the water-soluble gallium source comprises gallium nitrate, gallium chloride, gallium ethoxide, gallium isopropoxide, gallium acetylacetonate or gallium triethylate.

7. The method of claim 3 or 4, wherein the water-soluble tin source comprises stannous chloride dihydrate, stannic chloride, sodium stannate, tetraphenyltin, stannic acetylacetonate chloride, stannous sulfate, or stannic acetate.

8. The preparation method according to claim 3, wherein the calcination is carried out at a temperature of 500 to 1000 ℃ for 2 to 6 hours.

9. The preparation method according to claim 3, wherein the reducing gas used in the reduction reaction comprises one or more of hydrogen, methane, hydrogen sulfide and ammonia;

the temperature of the reduction reaction is 200-600 ℃, and the time is 1-5 h.

10. Use of the boron nitride supported rhodium-gallium-tin liquid alloy catalyst according to any one of claims 1 to 2 or the boron nitride supported rhodium-gallium-tin liquid alloy catalyst prepared by the preparation method according to any one of claims 3 to 9 in removing acetylene from ethylene by catalytic hydrogenation.

Technical Field

The invention relates to the technical field of catalysts, in particular to a boron nitride loaded rhodium-gallium-tin liquid alloy catalyst and a preparation method and application thereof.

Background

Petroleum cracking is a process for producing ethylene that is commonly used in industry, but the ethylene obtained usually contains traces of acetylene. The content of acetylene seriously affects the ethylene polymerization reaction, so that the quality of polyethylene is obviously reduced, and therefore, acetylene removal is urgently needed in the industry to reduce the content of acetylene to be less than 5ppm, which is a hot point of research in recent years.

At present, the common methods for removing trace acetylene from ethylene are a partial oxidation steam conversion method and a catalytic hydrogenation reaction method. The catalytic hydrogenation reaction is a main method for industrially removing trace acetylene due to mild reaction conditions, low energy consumption and convenient operation. The choice of catalyst during the hydrogenation reaction is an important factor affecting the reaction result.

Because Pd has good adsorptivity for acetylene and can activate acetylene to promote the conversion of acetylene, the supported Pd catalyst is widely used in industry. However, Pd metal is expensive, and the activity and reaction selectivity for acetylene are still insufficient, and in order to improve the catalytic performance of Pd catalysts, Pd is often mixed with other metals such as Ag or Au, or Pd is supported on a carrier such as silica or alumina. However, the catalytic activity of the supported Pd catalyst is low.

Disclosure of Invention

The invention aims to provide a boron nitride loaded rhodium-gallium-tin liquid alloy catalyst, and a preparation method and application thereof.

In order to achieve the above object, the present invention provides the following technical solutions:

the invention provides a boron nitride loaded rhodium-gallium-tin liquid alloy catalyst, which comprises boron nitride and an active component loaded on the surface of the boron nitride; the active component includes a rhodium gallium tin liquid alloy.

Preferably, the content of the active component in the boron nitride supported rhodium-gallium-tin liquid alloy catalyst is 0.8-8.5 wt%.

The invention provides a preparation method of a boron nitride loaded rhodium-gallium-tin liquid alloy catalyst in the technical scheme, which comprises the following steps:

mixing a water-soluble rhodium source, a water-soluble gallium source, a water-soluble tin source and water, mixing the obtained mixed solution with boron nitride, standing, dipping and drying to obtain a catalyst precursor;

and sequentially carrying out calcination and reduction reaction on the catalyst precursor to obtain the boron nitride loaded rhodium-gallium-tin liquid alloy catalyst.

Preferably, the mass ratios of the water-soluble rhodium source, the water-soluble gallium source, the water-soluble tin source and the boron nitride are respectively 0.002-0.015: 0.003 to 0.04: 0.003 to 0.04: 1.

preferably, the water-soluble rhodium source comprises rhodium chloride, rhodium nitrate, ammonium chlororhodate, rhodium sulfate, potassium hexachlororhodium (III) or rhodium (III) triacetylacetonate.

Preferably, the water-soluble gallium source comprises gallium nitrate, gallium chloride, gallium ethoxide, gallium isopropoxide, gallium acetylacetonate or gallium triethylate.

Preferably, the water-soluble tin source comprises stannous chloride dihydrate, stannic chloride, sodium stannate, tetraphenyltin, acetylacetonatostannic chloride, stannous sulfate or stannic acetate.

Preferably, the calcining temperature is 500-1000 ℃, and the time is 2-6 h.

Preferably, the reducing gas used in the reduction reaction comprises one or more of hydrogen, methane, hydrogen sulfide and ammonia gas;

the temperature of the reduction reaction is 200-600 ℃, and the time is 1-5 h.

The invention also provides the application of the boron nitride supported rhodium-gallium-tin liquid alloy catalyst prepared by the preparation method in the technical scheme in removing acetylene in ethylene by catalytic hydrogenation.

The invention provides a boron nitride loaded rhodium-gallium-tin liquid alloy catalyst, which comprises boron nitride and an active component loaded on the surface of the boron nitride; the active component includes a rhodium gallium tin liquid alloy. The invention takes rhodium, gallium and tin as active components, and strong metal bonds are formed among rhodium atoms, gallium atoms and tin atoms, so that the stability is high, the bonding force with a boron nitride carrier is strong, rhodium, gallium and tin can not agglomerate, uniform active centers can be obtained, and the catalytic activity of the catalyst can be improved; and the cost is greatly reduced compared with the cost of noble metals (Pd, Ag and Au). The invention takes boron nitride as a carrier, can improve the dispersibility of rhodium, gallium and tin in the catalyst and the binding force with the rhodium, the gallium and the tin, and is beneficial to increasing the catalytic activity and the stability of the catalyst. The boron nitride loaded rhodium-gallium-tin liquid alloy catalyst provided by the invention forms a self-protection oxide layer liquid film in the process of removing acetylene in ethylene through catalytic hydrogenation, and can avoid secondary reaction of ethylene on the surface of the catalyst, so that the formation of ethane by-products through deep hydrogenation of acetylene is inhibited, and the catalytic activity on acetylene is high.

The invention provides a preparation method of the boron nitride loaded rhodium-gallium-tin liquid alloy catalyst, which is simple to operate, low in raw material cost, free of secondary pollution and suitable for industrial production.

Drawings

FIG. 1 is a TEM image of a boron nitride supported rhodium gallium tin liquid alloy catalyst prepared in example 1;

FIG. 2 is a graph showing the catalytic effect of the boron nitride supported rhodium-gallium-tin liquid alloy catalyst prepared in example 1 on the hydrogenation of acetylene;

FIG. 3 is a graph showing the catalytic effect of the boron nitride supported rhodium-gallium-tin liquid alloy catalyst prepared in example 2 on the hydrogenation of acetylene;

FIG. 4 is a graph showing the catalytic effect of the boron nitride supported rhodium-gallium-tin liquid alloy catalyst prepared in example 3 on the hydrogenation of acetylene;

FIG. 5 is a graph showing the catalytic effect of the boron nitride supported rhodium-gallium-tin liquid alloy catalyst prepared in example 4 on the hydrogenation of acetylene;

FIG. 6 is a graph showing the catalytic effect of the boron nitride supported rhodium-gallium-tin liquid alloy catalyst prepared in example 5 on the hydrogenation of acetylene;

FIG. 7 is a graph showing the catalytic effect of the boron nitride supported rhodium-gallium-tin liquid alloy catalyst prepared in comparative example 1 on acetylene hydrogenation;

fig. 8 is a graph showing the catalytic effect of the boron nitride supported rhodium-gallium-tin liquid alloy catalyst prepared in comparative example 2 on acetylene hydrogenation.

Detailed Description

The invention provides a boron nitride loaded rhodium-gallium-tin liquid alloy catalyst, which comprises boron nitride and an active component loaded on the surface of the boron nitride; the active component includes a rhodium gallium tin liquid alloy.

In the invention, the content of the active component in the boron nitride supported rhodium-gallium-tin liquid alloy catalyst is preferably 0.8-8.5 wt%, more preferably 1-8 wt%, and most preferably 2-7 wt%. In the invention, in the boron nitride supported rhodium-gallium-tin liquid alloy catalyst, the content of rhodium is preferably 0.2-1.5 wt%, more preferably 0.3-1.2 wt%, and most preferably 0.5-1 wt%; the content of gallium is preferably 0.3 to 4 wt%, more preferably 1 to 3 wt%, most preferably 1.5 to 2.5 wt%; the tin content is preferably 0.3 to 4 wt%, more preferably 1 to 3 wt%, most preferably 1.5 to 2.5 wt%. In the invention, a stable structure of the trimetal liquid alloy is formed among rhodium atoms in a rhodium elementary substance, gallium atoms in a gallium elementary substance and tin atoms in a tin elementary substance in the rhodium-gallium-tin liquid alloy, so that rhodium, gallium and tin are not aggregated, the bonding effect with a boron nitride carrier is strong, uniform active centers can be obtained, and the catalytic activity of the catalyst can be improved; and the cost is greatly reduced compared with the cost of noble metals (Pd, Ag and Au).

The invention provides a preparation method of a boron nitride loaded rhodium-gallium-tin liquid alloy catalyst in the technical scheme, which comprises the following steps:

mixing a water-soluble rhodium source, a water-soluble gallium source, a water-soluble tin source and water, mixing the obtained mixed solution with boron nitride, standing, dipping and drying to obtain a catalyst precursor;

and sequentially carrying out calcination and reduction reaction on the catalyst precursor to obtain the boron nitride loaded rhodium-gallium-tin liquid alloy catalyst.

In the present invention, all the raw material components are commercially available products well known to those skilled in the art unless otherwise specified.

The method comprises the steps of mixing a water-soluble rhodium source, a water-soluble gallium source, a water-soluble tin source and water, mixing the obtained mixed solution with boron nitride, standing, dipping and drying to obtain a catalyst precursor.

In the present invention, the water-soluble rhodium source preferably includes rhodium chloride, rhodium nitrate, ammonium chlororhodate, rhodium sulfate, potassium hexachlororhodium (III) or rhodium (III) triacetylacetonate, and more preferably is rhodium chloride. In the present invention, the water-soluble gallium source preferably includes gallium nitrate, gallium chloride, gallium ethoxide, gallium isopropoxide, gallium acetylacetonate or gallium triethylate, and more preferably gallium chloride. In the present invention, the water-soluble tin source preferably includes stannous chloride dihydrate, stannic chloride, sodium stannate, tetraphenyltin, acetylacetonatostannic chloride, stannous sulfate or stannic ethoxide, more preferably stannous chloride dihydrate.

In the invention, the mass of the water-soluble rhodium source, the mass of the water-soluble gallium source and the mass of the water-soluble tin source are respectively calculated according to the mass of rhodium, gallium and tin, and the mass ratio of the water-soluble rhodium source, the water-soluble gallium source, the water-soluble tin source and boron nitride is preferably 0.002-0.015: 0.003 to 0.04: 0.003 to 0.04: 1, more preferably 0.003 to 0.012: 0.01-0.03: 0.01-0.03: 1, most preferably 0.005 to 0.01: 0.015 to 0.025: 0.015 to 0.025: 1.

in the invention, the mixing of the water-soluble rhodium source, the water-soluble gallium source, the water-soluble tin source and the water preferably comprises the steps of firstly mixing the water-soluble rhodium source and the first part of water to obtain a rhodium source solution; secondly, mixing the water-soluble gallium source with second part of water to obtain a gallium source solution; thirdly mixing the water-soluble tin source with the third part of water to obtain a tin source solution; and fourthly, mixing the rhodium source solution, the gallium source solution, the tin source solution and the residual water to obtain a mixed solution. The dosage of the first part of water, the second part of water and the third part of water is not particularly limited, and the concentrations of the rhodium source solution, the gallium source solution and the tin source solution can be ensured to be 5-15 mg/mL independently, more preferably 8-12 mg/mL, and even more preferably 10 mg/mL. The using amount of the residual water is not particularly limited, and the mass volume ratio of the boron nitride to the mixed solution is ensured to be 1 g: 20 mL. In the present invention, the first mixing, the second mixing, the third mixing and the fourth mixing are all preferably stirring mixing, and the speed of the stirring mixing is not particularly limited in the present invention, and the raw materials may be uniformly mixed. In the present invention, the time for the first mixing, the second mixing, and the third mixing is not particularly limited, and the water-soluble rhodium source, the water-soluble gallium source, or the water-soluble tin source may be dissolved in water. In the invention, the time for the fourth mixing is preferably 0.5-1 h.

In the present invention, when gallium chloride (GaCl) is used₃) In the case of a water-soluble gallium source, the GaCl is preferably used₃Dissolving in strong acid, and then mixing with the second part of water to obtain chloropalladate solution; the strong acid preferably comprises hydrochloric acid, nitric acid or sulfuric acid; the concentration of the strong acid is preferably 10-12 mol/L, and more preferably 12 mol/L; the mass-to-volume ratio of the palladium chloride to the strong acid is preferably 1 g: 1-3 mL, more preferably 1 g: 3 mL. The invention firstly prepares GaCl₃Dissolving in concentrated hydrochloric acid to make trivalent gallium ion form Ga^{3 +}The form exists.

In the invention, when the stannous chloride dihydrate is used as the water-soluble tin source, the stannous chloride dihydrate is preferably dissolved in strong acid and then mixed with the third part of water to obtain the acid solution of the stannous chloride; the strong acid preferably comprises hydrochloric acid, nitric acid or sulfuric acid; the concentration of the strong acid is 10-12 mol/L, and more preferably 12 mol/L; the mass volume ratio of the stannous chloride to the strong acid is preferably 1 g: 1-3 mL, more preferably 1 g: 3mL, can avoid the stannous chloride dihydrate to decompose in neutral aqueous solution to generate precipitate.

In the present invention, the mixing of the mixed solution and boron nitride is preferably performed by stirring, and the stirring and mixing speed is not particularly limited, and the raw materials may be uniformly mixed. In the invention, the mixing time is preferably 0.5-1 h.

In the invention, the standing impregnation is preferably carried out under a standing condition, and the standing time is preferably 6-12 hours, and more preferably 8-10 hours. In the invention, in the standing dipping process, the water-soluble rhodium source, the water-soluble gallium source and the water-soluble tin source are loaded on the surface of the boron nitride.

In the invention, the drying is preferably vacuum drying, and the temperature of the vacuum drying is preferably 70-100 ℃, and more preferably 80 ℃; the vacuum drying time is preferably 6-15 hours, and more preferably 8-12 hours.

After the catalyst precursor is obtained, the catalyst precursor is sequentially subjected to calcination and reduction reaction to obtain the boron nitride loaded rhodium-gallium-tin liquid alloy catalyst.

In the invention, the calcining temperature is preferably 500-1000 ℃, and more preferably 600-800 ℃; the calcination time is preferably 2-6 h, and more preferably 3-5 h. In the present invention, the calcination is preferably carried out in a protective atmosphere, which is preferably nitrogen or argon. In the calcining process, the water-soluble rhodium source, the water-soluble gallium source and the water-soluble tin source are subjected to in-situ thermal decomposition on the surface of boron nitride to respectively obtain rhodium oxide, gallium oxide and tin oxide.

In the present invention, the reducing gas used in the reduction reaction preferably includes one or more of hydrogen, methane, hydrogen sulfide and ammonia gas, more preferably includes hydrogen, methane, hydrogen sulfide or ammonia gas, and most preferably hydrogen. When the reducing gases used in the present invention are two or more, the ratio of the reducing gases used in the present invention is not particularly limited, and may be any ratio. In the present invention, the ratio of the flow rate of the calcined product to the reducing gas is preferably 0.5 g: 30-50 mL/min, more preferably 0.5 g: 40 mL/min.

In the invention, the temperature of the reduction reaction is preferably 200-600 ℃, and more preferably 300-500 ℃; the time of the reduction reaction is preferably 1-5 h, and more preferably 2-4 h. In the invention, in the reduction reaction process, rhodium oxide, gallium oxide and tin oxide are respectively reduced into elementary rhodium, elementary gallium and elementary tin, and simultaneously, active components rhodium, gallium and tin interact to form a liquid stable structure of three metals, so that rhodium, gallium and tin cannot agglomerate, and the combination effect of rhodium, gallium and tin with a boron nitride carrier is strong, thereby being beneficial to increasing the catalytic activity and stability of the catalyst.

The preparation method provided by the invention is simple to operate, low in raw material cost, free of secondary pollution due to the fact that water is used as a solvent, and suitable for industrial production.

The invention also provides the application of the boron nitride supported rhodium-gallium-tin liquid alloy catalyst prepared by the preparation method in the technical scheme in removing acetylene in ethylene by catalytic hydrogenation.

In the invention, the boron nitride loaded rhodium-gallium-tin liquid alloy catalyst is preferably subjected to activation treatment before application. In the invention, the activation treatment is preferably reduction activation of the boron nitride supported rhodium-gallium-tin liquid alloy catalyst by using hydrogen; the ratio of the mass of the boron nitride-loaded rhodium-gallium-tin liquid alloy catalyst to the volume of hydrogen is preferably 1 g: (200-6000) mL, more preferably 1 g: (1000-3000) mL; the temperature of the activation treatment is preferably 100-300 ℃, and is preferably 150-250 ℃; the time of the activation treatment is preferably 0.5-2 h, and more preferably 1 h.

In the invention, the reaction conditions of the boron nitride supported rhodium-gallium-tin liquid alloy catalyst for removing acetylene in ethylene by catalytic hydrogenation preferably comprise: the reaction gas is preferably C₂H₂/H₂/C₂H₄Mixing the gas; c in the reaction gas₂H₂、H₂And C₂H₄Is preferably 1: 2-10: 60-100, more preferably 1: 3-8: 70-90, most preferably 1: 4-6: 70-80, and the volume space velocity of the reaction gas is 1000-36000 h^-1More preferably 1100 to 10000h^-1More preferably 1200 to 5000 hours^-1(ii) a The ratio of the mass of the boron nitride supported rhodium-gallium-tin liquid alloy catalyst to the reaction gas pressure is preferably 0.2g (0.05-0.2) MPa, and more preferably 0.2g (0.05-0.1) MPa; the reaction temperature is preferably 30-210 ℃, more preferably 50-180 ℃, and most preferably 80-120 ℃; the reaction time is preferably 30 to 60 hours, and more preferably 40 to 50 hours.

In the invention, the preparation of ethylene by acetylene hydrogenation is preferably carried out in a fixed bed reactor, more preferably a fixed bed microreactor; the fixed bed micro-reactor has a fixed bed cavity inner diameter of preferably 2cm and a constant temperature heating zone length of preferably 10 cm.

In the embodiment of the invention, the catalytic effect of the boron nitride supported rhodium-gallium-tin liquid alloy catalyst is preferably analyzed by using a gas chromatograph of a FID detector, wherein the sampling interval time is preferably 0.5 h.

The boron nitride-loaded rhodium-gallium-tin liquid alloy catalyst forms a self-protection oxide layer liquid film in the process of preparing ethylene by catalyzing acetylene hydrogenation, and can avoid secondary reaction of ethylene on the surface of the catalyst, so that the formation of ethane byproducts by deep hydrogenation of acetylene is inhibited, and the catalyst has high selectivity and catalytic activity on ethylene.

The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.