阅读说明：本技术 一种铜掺杂复合催化剂及其制备方法和应用 (Copper-doped composite catalyst and preparation method and application thereof ) 是由 魏天荣 孙苏红 陈坤 於国伟 薛耘芸 张小元 李善华 于 2020-04-13 设计创作，主要内容包括：本发明公开了一种铜掺杂复合催化剂及其制备方法和应用,该催化剂的活性组分包括第一活性组分和/或第二活性组分,第一活性组分为ZrO<Sub>2</Sub>或MoO<Sub>3</Sub>,第二活性组分为CuO,第一活性组分和载体的质量比为(5-30)：(95-70),第二活性组分质量分数为5-20wt%。制备方法为用硝酸将活性组分氧化锆或氧化钼与载体混合均匀,然后成型,在30-150℃干燥1-10h,再在200-700℃下焙烧1-24h,然后浸渍在铜的盐溶液中1-48h,在70-120℃干燥1-10h,再在200-600℃下焙烧1-24h,得到歧化反应制备碳酸二苯酯用新型催化剂。该催化剂对甲基苯基碳酸酯歧化反应制备碳酸二苯酯具有较高的活性和选择性,甲基苯基碳酸酯转化率可达60%以上,产物选择性大于99%。(The invention discloses a copper-doped composite catalyst and a preparation method and application thereof, wherein the active component of the catalyst comprises a first active component and/or a second active component, and the first active component is ZrO 2 Or MoO 3 A second active ingredientThe CuO is adopted, and the mass ratio of the first active component to the carrier is (5-30): (95-70), and the mass fraction of the second active component is 5-20 wt%. The preparation method comprises the steps of uniformly mixing zirconium oxide or molybdenum oxide serving as an active component with a carrier by nitric acid, then forming, drying at 30-150 ℃ for 1-10h, roasting at 200-700 ℃ for 1-24h, then soaking in a copper salt solution for 1-48h, drying at 70-120 ℃ for 1-10h, and roasting at 200-600 ℃ for 1-24h to obtain the novel catalyst for preparing the diphenyl carbonate by the disproportionation reaction. The catalyst has higher activity and selectivity for preparing diphenyl carbonate by disproportionation reaction of methyl phenyl carbonate, the conversion rate of the methyl phenyl carbonate can reach more than 60 percent, and the product selectivity is more than 99 percent.)

1. A copper-doped composite catalyst characterized by: the active component of the catalyst comprises a first active component and/or a second active component, wherein the first active component is ZrO₂Or MoO₃The second active component is CuO, and the mass ratio of the first active component to the carrier is (5-30): (95-70), and the mass fraction of the second active component is 5-20 wt%.

2. The copper-doped composite catalyst according to claim 1, characterized in that: the carrier is HZSM-5 molecular sieve.

3. A method for preparing the copper-doped composite catalyst according to any one of claims 1 to 2, characterized in that: the preparation method comprises the following steps:

1) uniformly mixing the first active component and the carrier by using nitric acid, and then forming to obtain a catalyst intermediate A;

2) drying the catalyst intermediate A at 30-150 ℃ for 1-10h, and then roasting at 200-700 ℃ for 1-24h to obtain a catalyst intermediate B, namely a catalyst with an active component as a first active component;

3) the catalyst intermediate B is soaked in a copper salt solution for 1-48h, dried at 70-120 ℃ for 1-10h and then roasted at 200-600 ℃ for 1-24h to obtain the copper-doped composite catalyst, namely the catalyst with the active component comprising a first active component and a second active component.

4. The method of claim 3, wherein: the concentration of the nitric acid in the step 1) is 5-30 wt%.

5. The method of claim 3, wherein: the salt solution of copper in the step 3) is copper nitrate, copper acetate and copper sulfate.

6. The method of claim 3, wherein: when the catalyst in the step 1) is molded, the catalyst is made into a strip shape, the length of the strip shape is 0.5-1.5cm, and the diameter of the strip shape is 1-3 mm.

7. The catalyst of any one of claims 1 to 2 or the catalyst prepared by the method of any one of claims 3 to 6 is used for the disproportionation of methyl phenyl carbonate to prepare diphenyl carbonate.

8. Use according to claim 7, characterized in that: during the disproportionation reaction, the pressure is 100-760mmHg, the catalyst dosage is 0.01-0.1wt%, the reaction time is 1-8h, and the reaction temperature is 140-220 ℃.

Technical Field

The invention belongs to the technical field of catalyst preparation and application, and relates to a copper-doped composite catalyst and a preparation method and application thereof.

Background

Diphenyl carbonate is an important organic intermediate, can synthesize a plurality of important organic compounds and high molecular materials, and can replace phosgene to react with bisphenol A to synthesize polycarbonate with excellent performance. At present, the most studied method for synthesizing diphenyl carbonate is the ester exchange method, including the ester exchange method of dimethyl carbonate and phenol, the ester exchange method of dimethyl oxalate and phenol, and the ester exchange method of carboxylic ester and dimethyl carbonate, wherein the method for synthesizing diphenyl carbonate by dimethyl carbonate and phenol is the main method.

In the disproportionation reaction stage, the catalyst for synthesizing diphenyl carbonate from methyl phenyl carbonate mainly comprises an organic titanium catalyst, an organic tin catalyst, a metal oxide composite catalyst and the like. In CN101491761A introduces a Pb-Cu composite oxide catalyst for disproportionation of methyl phenyl carbonate, which is prepared by a solution mixing method and a mechanical method, the highest yield of diphenyl carbonate exceeds 80 percent, the catalyst has poor mechanical strength, an active component lead is easy to run off, and the catalyst activity is reduced by repeated use. CN106140133B discloses a PbO/ZrO₂The catalyst has the problems that the conversion rate of methyl phenyl carbonate reaches 76.6 percent, the yield of diphenyl carbonate reaches 76.1 percent, and active components are easy to lose. In "diphenyl carbonate synthesized by disproportionation of methylphenyl carbonate catalyzed by organotin compound" and "research on disproportionation of methylphenyl carbonate catalyzed by organotitanium compound", Wangselin et al studied organotin and organotitanium catalysts, respectively, wherein BuSnO (OH) catalyst in organotin has the best effect, the conversion rate of methylphenyl carbonate is up to 89.7%, and the selectivity and yield of diphenyl carbonate are 99.3% and 89.1%, respectively. In the organic titanium catalyst, tetraisopropyl titanate is used as a catalyst, the conversion rate of methyl phenyl carbonate reaches 90.3%, and the selectivity of diphenyl carbonate reaches 99.9%. "research on diphenyl carbonate and methyl phenyl carbonate synthesized by transesterification" in Xiyuanhong et al adopts Mg-Al hydrotalcite and isopropyl titanate as catalyst, and under the condition of reduced pressure of 600mmHg, the conversion rate of methyl phenyl carbonate is 63%, and the catalyst has the problem of poor repeatability.

Disclosure of Invention

The invention provides a copper-doped composite catalyst, a preparation method and application thereof, which can solve the problems of difficult separation, easy loss and difficult regeneration of the existing catalyst and have the advantages of high stability, easy separation and regeneration.

The technical scheme adopted by the invention is as follows:

the active component of the copper-doped composite catalyst comprises a first active component and/or a second active component, wherein the first active component is ZrO₂Or MoO₃The second active component is CuO, and the mass ratio of the first active component to the carrier is (5-30): (95-70), and the mass fraction of the second active component is 5-20 wt%.

Preferably, the support is an HZSM-5 molecular sieve.

The preparation method of the copper-doped composite catalyst comprises the following steps:

1) uniformly mixing the first active component and the carrier by using nitric acid, and then forming to obtain a catalyst intermediate A;

2) drying the catalyst intermediate A at 30-150 ℃ for 1-10h, and then roasting at 200-700 ℃ for 1-24h to obtain a catalyst intermediate B, namely a catalyst with an active component as a first active component;

3) the catalyst intermediate B is soaked in a copper salt solution for 1-48h, dried at 70-120 ℃ for 1-10h and then roasted at 200-600 ℃ for 1-24h to obtain the copper-doped composite catalyst, namely the catalyst with the active component comprising a first active component and a second active component.

Preferably, the concentration of the nitric acid of the step 1) is 5 to 30 wt%.

Preferably, the salt solution of copper in step 3) is copper nitrate, copper acetate or copper sulfate.

Preferably, when the catalyst in the step 1) is molded, the catalyst is made into a strip shape, the length of the strip shape is 0.5-1.5cm, and the diameter of the strip shape is 1-3 mm.

The catalyst or the catalyst prepared by the method is used for carrying out a methyl phenyl carbonate disproportionation reaction to prepare diphenyl carbonate.

Preferably, the pressure is 100-760mmHg, the catalyst is used in 0.01-0.1wt%, the reaction time is 1-8h, and the reaction temperature is 140-220 ℃ during the disproportionation reaction.

The diphenyl carbonate and dimethyl carbonate are generated by the disproportionation reaction of methyl phenyl carbonate, the yield of the diphenyl carbonate is directly influenced by the disproportionation reaction rate of the methyl phenyl carbonate, the method for improving the yield of the diphenyl carbonate breaks the reaction balance, removes the dimethyl carbonate and reduces the probability of reverse reaction on one hand, and the method for improving the yield of the diphenyl carbonate adds a feasible catalyst on the other hand, accelerates the reaction rate, reduces the reaction time and reduces the generation of byproducts.

The invention has the following beneficial effects:

1. the disproportionation reaction process of methyl phenyl carbonate needs a catalyst with a weak acid center, the HZSM-5 molecular sieve as a carrier has weak acid, medium strong acid and strong acid centers, molybdenum oxide contains the weak acid center, and copper oxide and zirconium oxide are amphoteric oxides and have both an acid center and a basic center, wherein the basic center can weaken the strong acid center of the molecular sieve carrier, so that the generation of byproducts caused by the over-strong acidity of the catalyst is avoided.

2. Copper is doped in the catalyst, so that on one hand, zirconium oxide and molybdenum oxide can be activated, and the catalytic activity of the catalyst is improved; on the other hand, the first active component can be dispersed by adopting a copper salt solution impregnation method, the dispersion degree of copper on the surface of the catalyst can be increased, the surface ion agglomeration is hindered, the dispersion degree and the catalytic circulation stability of the active component in the catalyst are improved, the sintering and agglomeration phenomena of the catalyst are effectively inhibited, and the catalytic activity of the catalyst is further improved.

3. The copper is doped in the catalyst, so that the synergistic effect of the molybdenum-copper or zirconium-copper serving as an active component can be increased, the specific surface area of the catalyst can be increased through the synergistic effect, and the pore structure of the catalyst can be changed, so that the catalytic activity of the catalyst is improved.

4. Nitric acid is added in the preparation of the catalyst to be used as a binder, so that the catalyst is molded, the strength of the catalyst is increased, and the loss of active components is avoided.

5. The catalyst molding can avoid the catalyst and the product from being mixed together, the later separation can be simpler, and the problems that the catalyst and the product are difficult to separate and regenerate are solved.

6. The method for preparing the catalyst has the advantages of simple operation, low cost and easy industrialization.

Detailed Description

The invention will be further elucidated with reference to the following examples.