CN110614093A - Preparation method of low-content gold and ruthenium bimetallic catalyst for acetylene hydrochlorination - Google Patents

Abstract

The invention aims to solve the technical problem of providing a preparation method and a use method of a low-content gold-ruthenium bimetallic catalyst for acetylene hydrochlorination, wherein HAuCl is used₄•4H₂O and RuCl₃Preparing a certain amount of mixed solution, dropwise adding the prepared mixed solution into the activated carbon while stirring, performing ultrasonic treatment at 45 ℃ for 35 min on a sample obtained after the dropwise adding of the mixed solution is completed, soaking at 25 ℃ for 12 h, and finally drying at 90 ℃ for 12 h to prepare the vinyl chloride-gold-ruthenium bimetallic catalyst prepared by hydrochlorination of acetylene, and applying the catalyst to a fixed bed reactor; the preparation method of the catalyst has simple process; the cost is low; the prepared catalyst has better catalytic activity and stability when applied to the reaction of preparing vinyl chloride by hydrochlorinating acetylene, the conversion rate of acetylene is 95.7 percent, and the selectivity of vinyl chloride is 99.0 percent.

Description

Preparation method of low-content gold and ruthenium bimetallic catalyst for acetylene hydrochlorination

Technical Field

The invention relates to a preparation method of a bimetallic catalyst with low content of aurum and ruthenium for acetylene hydrochlorination, in particular to a catalyst for preparing vinyl chloride by acetylene hydrochlorination, which has good acetylene conversion rate and vinyl chloride selectivity.

Background

Polyvinyl chloride (abbreviated as PVC) is one of five engineering plastics worldwide, and is generally polymerized from vinyl chloride (abbreviated as VCM) monomer. At present, the production process of synthesizing vinyl chloride is mainly divided into three processes, namely an ethane oxychlorination process using ethane as a raw material, an ethylene process using ethylene as a raw material and an acetylene hydrochlorination process using acetylene as a raw material. The hydrochlorination of acetylene, in which acetylene is the starting material, is the main process for the production of vinyl chloride. However, this method uses HgCl₂the/AC catalyst causes serious mercury loss in the reaction process, causes serious pollution to the environment and also causes great harm to human bodies. Therefore, research and development of a mercury-free and environment-friendly acetylene hydrochlorination catalyst are one of the main problems which are urgently needed to be solved by the majority of technologists.

In recent years, researchers have increasingly studied nonmetallic catalysts for hydrochlorination of acetylene. However, most of the non-metallic catalytic materials reported at present have the same disadvantages, namely unstable performance and short service life, which makes the non-metallic catalytic materials unable to meet the requirements for the performance of the catalytic materials in the industrial production of vinyl chloride. In addition, the price of the non-noble metal catalyst is far lower than that of the noble metal catalyst, but the non-noble metal catalyst generally has the defects of low acetylene conversion rate and poor stability, and the industrial application of the non-noble metal catalyst in acetylene hydrochlorination is also limited.

The development of gold-based catalysts as catalysts for the hydrochlorination of acetylene is limited mainly by two reasons for the supported gold-based catalysts in noble metal catalysts, the first being the addition reaction of the catalysts at temperatures in the range of 60 ℃ to 100 ℃ between acetylene and hydrogen chlorideIn which carbon deposition occurs, resulting in the deactivation of the catalyst during the reaction. The second reason is that the active species Au is generated in the reaction temperature range of 120 ℃ to 180 DEG C³⁺Is very easy to be reduced into Au⁰Resulting in easy deactivation of the catalyst during the reaction. So that the gold catalyst is deactivated quickly and can not meet the industrial requirements. However, the gold content of the gold catalysts reported in the literature is high, mostly 1wt%, and gold is expensive and has poor stability, and these disadvantages severely restrict the development of gold-based catalysts. The ruthenium-based catalyst has certain acetylene hydrochlorination catalytic activity due to the low price compared with the gold-based catalyst, and has the problems of low activity and poor stability. Thus, a relatively inexpensive RuCl was selected₃With AuCl₃The bimetallic metal with low content of gold and ruthenium is prepared to effectively improve the activity and stability of the single gold catalyst or the single ruthenium catalyst. Therefore, the patent provides a preparation method of the bimetallic catalyst for preparing vinyl chloride from acetylene through hydrochlorination and low-content aurum and ruthenium. At normal pressure, reaction temperature of 150 ℃ and acetylene space velocity of 570 h^-1Total airspeed 1224 h^-1，V（HCl）/V(C₂H₂) The acetylene hydrochlorination test is carried out under the reaction condition of =1.15, and the result shows that the catalyst has excellent catalytic performance.

Disclosure of Invention

The invention aims to solve the technical problem of providing a preparation method of a low-content gold and ruthenium bimetallic catalyst for acetylene hydrochlorination. The catalyst is applied to the reaction of preparing chloroethylene by hydrochlorinating acetylene, and has higher acetylene conversion rate and chloroethylene selectivity.

The preparation method of the catalyst adopts an isometric impregnation method, and the carrier pretreatment comprises the following steps: firstly, HNO with the concentration of 65 percent is added₃Diluting with deionized water at a ratio of 1:5, adding coconut shell activated carbon into the diluted nitric acid solution, stirring and washing at 25 deg.C for 3 h to obtain suspension, filtering and washing with deionized water until pH is neutral, and drying the obtained activated carbon at 90 deg.C for 2-15 h to serve as a carrier, and marking as AC.

Adding HAuCl₄•4H₂Preparing Au ethanol solution with Au content of 0.478% by using O (assay: 47.8%),adding RuCl₃(assoy: 47.0%) to prepare a ruthenium ethanol solution with the Ru content of 0.470% for later use, respectively weighing AC according to the molar ratio of AC to Au to Ru =1 to 0.000457 to 0.000297, and weighing the gold ethanol solution and the ruthenium ethanol solution. Adding a certain amount of HAuCl into a beaker according to the mass percent of gold accounting for 0.75 percent of the active carbon carrier₄•4H₂O absolute ethyl alcohol solution, then adding a certain amount of RuCl according to the mass percent of ruthenium content accounting for 0.25 percent of the active carbon carrier₃And uniformly mixing the absolute ethyl alcohol solution, continuously adding a certain amount of absolute ethyl alcohol to form an impregnation solution, then dropwise adding the impregnation solution on activated carbon while stirring, performing ultrasonic treatment on the obtained sample at 45 ℃ for 35 min, soaking the sample at 25 ℃ for 12 h, and drying the sample at 90 ℃ for 12 h to obtain the chloroethylene gold ruthenium bimetallic catalyst sample 1 prepared by acetylene hydrochlorination. A gold catalyst sample 2 (comparative sample 2) having a gold content of 1% by mass of the activated carbon carrier was prepared in the above-described manner at a molar ratio of AC: Au =1:0.000609, and a ruthenium catalyst sample 3 (comparative sample 3) having a ruthenium content of 1% by mass of the activated carbon carrier was prepared in the above-described manner at a molar ratio of AC: Ru =1: 0.00119.

The catalyst of the invention obtains better catalytic effect in the reaction of preparing vinyl chloride by hydrochlorinating acetylene. The main acetylene hydrochlorination conditions were as follows: at normal pressure, reaction temperature of 150 ℃ and acetylene space velocity of 570 h^-1Total airspeed 1224 h^-1，V（HCl）/V(C₂H₂) Under the reaction conditions of =1.15, the acetylene hydrochlorination catalytic performance was evaluated. The catalytic performance adopts acetylene (X)_A) Conversion rate of (2) and conversion rate to VCM (S)_VC) The selectivity of (A) was calculated as an evaluation criterion using the following formula: x_A = (φ_A0-φ_Al)/ φ_A0 X 100% and S_VC = φ_VC / (φ_A0-φ_Al) X 100%. Wherein phi_A0，φ_AlAnd phi_VCThe volume fraction of acetylene, the volume fraction of the remaining acetylene and the volume fraction of VCM in the raw material gas are respectively expressed.

Compared with the prior art, the invention has the following advantages:

(1) the prepared bimetallic catalyst for preparing vinyl chloride from acetylene by hydrochlorination and low-content aurum and ruthenium has better catalytic activity and service life, and the preparation method of the catalyst is simple.

(2) The low-content gold and ruthenium bimetallic catalyst prepared by an isometric impregnation method has the advantages that the activity and the stability of the catalyst are improved by adding ruthenium, the content of Au and Ru is reduced to be below 1%, and the price of ruthenium is about half of that of gold, so that the preparation cost of the catalyst is effectively reduced.

Drawings

FIG. 1 shows the acetylene conversion in the catalyst for the preparation of vinyl chloride by hydrochlorination of acetylene.

FIG. 2 shows the selectivity of vinyl chloride in the catalyst for preparing vinyl chloride by hydrochlorinating acetylene.

Detailed Description

The features of the present invention will be further illustrated by the following examples, which are not intended to limit the invention thereto.

Example 1: the preparation method of the catalyst adopts an isometric impregnation method, and firstly HNO with the concentration of 65 percent is added₃Diluted with deionized water at a ratio of 1:5, then 3 g of coconut shell activated carbon was added to the diluted nitric acid solution, washed with stirring at room temperature for 1-3 h, the resulting suspension was filtered and washed with deionized water until the pH was neutral, and the resulting activated carbon was dried at 90 ℃ for 2-15 h to serve as a support, labeled AC. 1 g of HAuCl₄•4H₂Dissolving O (assay: 47.8%) in anhydrous ethanol to obtain a gold ethanol solution with Au content of 0.478%, and adding 1 g RuCl₃(assoy: 47.0%) was dissolved in absolute ethanol to prepare a ruthenium ethanol solution having a Ru content of 0.470%, and 4.7 ml of HAuCl was measured₄•4H₂Oethanol solution and 1.6ml of RuCl prepared as described above₃Mixing ethanol solutions, continuously adding absolute ethanol to form 10 ml of impregnation liquid, dropwise adding the impregnation liquid into 3 g of activated carbon while stirring, performing ultrasonic treatment at 45 ℃ for 35 min, impregnating at 25 ℃ for 12 h, and drying at 90 ℃ for 12 h to obtain a vinyl chloride gold ruthenium bimetallic catalyst sample 1 prepared by hydrochlorinating acetylene, wherein the label is Au0.75% Ru0.25%/AC, gold in the catalyst sample accounts for 0.75% of an activated carbon carrier, and ruthenium in the activated carbon carrier0.25% of. At normal pressure, reaction temperature of 150 ℃ and acetylene space velocity of 570 h^-1Total airspeed 1224 h^-1，V（HCl）/V(C₂H₂) Under the reaction condition of =1.15, acetylene hydrochlorination test is carried out, and the test result shows that the acetylene conversion rate reaches 95.7% and the selectivity of vinyl chloride reaches 99.0%.

Example 2: the preparation method of the catalyst adopts an isometric impregnation method, and firstly HNO with the concentration of 65 percent is added₃Diluted with deionized water at a ratio of 1:5, then 3 g of coconut shell activated carbon was added to the diluted nitric acid solution, washed with stirring at room temperature for 1-3 h, the resulting suspension was filtered and washed with deionized water until the pH was neutral, and the resulting activated carbon was dried at 90 ℃ for 2-15 h to serve as a support, labeled AC. 1 g of HAuCl₄•4H₂Dissolving O (assay: 47.8%) in anhydrous ethanol to obtain gold ethanol solution containing Au 0.478%, and collecting 6.3 ml HAuCl₄•4H₂Adding absolute ethanol into the O ethanol solution to form 10 ml of impregnation liquid, dropwise adding the impregnation liquid into 3 g of activated carbon while stirring, dropwise adding the impregnation liquid while stirring, performing ultrasonic treatment on the obtained sample at 45 ℃ for 35 min, impregnating the sample at 25 ℃ for 12 h, and drying the sample at 90 ℃ for 12 h. And obtaining a catalyst sample 2 for preparing gold vinyl chloride by hydrochlorinating acetylene, wherein the label is Au1%/AC, and the gold in the catalyst sample accounts for 1% of the activated carbon carrier.

Example 3: the preparation method of the catalyst adopts an isometric impregnation method, and firstly HNO with the concentration of 65 percent is added₃Diluted with deionized water at a ratio of 1:5, then 3 g of coconut shell activated carbon was added to the diluted nitric acid solution, washed with stirring at room temperature for 1-3 h, the resulting suspension was filtered and washed with deionized water until the PH was neutral, and the resulting activated carbon was dried at 90 ℃ for 2-15 h to serve as a support, labeled AC. 1 g of RuCl₃(assoy: 47.0%) is dissolved in absolute ethyl alcohol to prepare ruthenium ethyl alcohol solution with Ru content of 0.470%, and the prepared 6.4 ml RuCl is taken₃Adding anhydrous ethanol into ethanol solution to obtain 10 ml of maceration extract, adding dropwise the maceration extract into 3 g of activated carbon under stirring, subjecting the obtained sample to ultrasonic treatment at 45 deg.C for 35 min, soaking at 25 deg.C for 12 h, and soaking at 90 deg.CDrying for 12 h gave ruthenium vinyl chloride catalyst sample 3, labeled Ru1%/AC, from hydrochlorination of acetylene. Wherein ruthenium in the catalyst sample accounted for 1% of the activated carbon support.

Claims (1)

1. A preparation method of a bimetallic catalyst with low content of gold and ruthenium for acetylene hydrochlorination adopts an isometric impregnation method, and is characterized in that the carrier pretreatment: firstly, HNO with the concentration of 65 percent is added₃Diluting with deionized water at a ratio of 1:5, adding coconut shell activated carbon into the diluted nitric acid solution, stirring and washing at 25 ℃ for 3 h to obtain a suspension, filtering and washing with deionized water until the pH value is neutral, and drying the obtained activated carbon at 90 ℃ for 2-15 h to serve as a carrier, wherein the label is AC; adding HAuCl₄•4H₂Preparing Au ethanol solution with Au content of 0.478% by using O (assay: 47.8%), and mixing RuCl₃(assoy: 47.0%) to prepare a ruthenium ethanol solution with Ru content of 0.470% for standby, respectively weighing AC according to the molar ratio of AC to Au to Ru =1 to 0.000457 to 0.000297, weighing a gold ethanol solution and a ruthenium ethanol solution, and adding a certain amount of HAuCl into a beaker according to the mass percentage of gold accounting for 0.75% of the activated carbon carrier₄•4H₂O absolute ethyl alcohol solution, then adding a certain amount of RuCl according to the mass percent of ruthenium content accounting for 0.25 percent of the active carbon carrier₃Uniformly mixing the absolute ethyl alcohol solution, continuously adding a certain amount of absolute ethyl alcohol to form an impregnation solution, then dropwise adding the impregnation solution on activated carbon, stirring and dropwise adding, performing ultrasonic treatment on the obtained sample at 45 ℃ for 35 min, soaking at 25 ℃ for 12 h, and drying at 90 ℃ for 12 h to obtain a vinyl chloride-ruthenium bimetallic catalyst sample 1 prepared by hydrochlorination of acetylene; a gold catalyst sample 2 (comparative sample 2) having a gold content of 1 mass% of the activated carbon support was prepared in the above-described manner at a molar ratio of AC: Au =1: 0.000609; a ruthenium catalyst sample 3 (comparative sample 3) having a ruthenium content of 1 mass% based on the activated carbon carrier was prepared in the above-described manner at a molar ratio of AC: Ru =1: 0.00119.