阅读说明：本技术 一种己二酸酯加氢生产1,6-己二醇的催化剂及其制备方法 (Catalyst for producing 1, 6-hexanediol by hydrogenation of adipate and preparation method thereof ) 是由 侯珂珂 谭伟 韩立霞 崔勇 于 2019-09-19 设计创作，主要内容包括：本发明涉及加氢催化合成领域,具体涉及一种己二酸酯加氢生产1,6-己二醇的催化剂及其制备方法,该1,6-己二醇催化剂以CuO为主活性组分,ZnO为助剂组分,碱土金属氧化物改性的Al<Sub>2</Sub>O<Sub>3</Sub>材料为载体,其中按重量份计,CuO为20-40份,ZnO为30-60份,碱土金属氧化物包含但不限于MgO、CaO、BaO中的一种或两种,为5-25份,Al<Sub>2</Sub>O<Sub>3</Sub>为5-20份。催化剂具有活性组分组成和含量可调变、活性位分布均匀,制备工艺简单的优势；同时,所述催化剂在相对较低的温度下,原料己二酸二甲酯转化率＞99.5％,产品1,6-己二醇选择性≥98％,为己二酸酯加氢生产1,6-己二醇提供极大的适用前景。(the invention relates to the field of hydrogenation catalytic synthesis, in particular to a catalyst for producing 1, 6-hexanediol by adipate hydrogenation and a preparation method thereof, wherein the 1, 6-hexanediol catalyst takes CuO as a main active component, ZnO as an auxiliary component and alkaline earth metal oxide modified Al 2 O 3 The material is a carrier, wherein, calculated by weight portion, CuO is 20-40 portions, ZnO is 30-60 portions, alkaline earth metal oxide comprises but is not limited to one or two of MgO, CaO and BaO,5 to 25 portions of Al 2 O 3 5-20 parts. The catalyst has the advantages of adjustable active component composition and content, uniform active site distribution and simple preparation process; meanwhile, the catalyst has the conversion rate of dimethyl adipate as a raw material of more than 99.5% and the selectivity of 1, 6-hexanediol as a product of more than or equal to 98% at a relatively low temperature, and provides a great application prospect for producing 1, 6-hexanediol by hydrogenation of adipate.)

1. a catalyst for the hydrogenation of adipate to produce 1, 6-hexanediol, characterized by: al modified by alkaline earth metal oxide and taking CuO as a main active component and ZnO as an auxiliary component₂O₃The material is a carrier;

wherein, the weight portion of CuO is 20 to 40 portions, the weight portion of ZnO is 30 to 60 portions, the weight portion of alkaline earth metal oxide is 5 to 25 portions, and Al is₂O₃5-20 parts;

wherein the alkaline earth metal oxide includes but is not limited to one or two of MgO, CaO, BaO.

2. The catalyst for the hydrogenation of adipate to produce 1, 6-hexanediol according to claim 1, characterized in that: the component substances are derived from pure substances or precursors thereof, and the precursors are respectively selected from:

Al₂O₃Can directly select Al₂O₃Powder or selected from aluminum hydroxide dry glue or pseudo-boehmite is used as a precursor;

the CuO, ZnO and alkaline earth metal oxide precursors adopt corresponding nitrates.

3. the process for preparing a catalyst for the hydrogenation of adipate to produce 1, 6-hexanediol according to claim 1, characterized in that: the method comprises the following specific steps:

(1)Al₂O₃Preparation of suspension

Weighing the formula amount of Al₂O₃adding water into the powder or the precursor corresponding to the powder to prepare suspension, stirring and uniformly dispersing the suspension;

(2) Preparation of solution A

Weighing precursors corresponding to CuO, ZnO and alkaline earth metal oxides in a formula amount, mixing the precursors with water, and uniformly stirring to obtain a solution A;

(3) Preparation of solution B

And weighing sodium carbonate and sodium hydroxide, mixing with water and uniformly stirring to obtain a solution B. Wherein the mass ratio of the sodium carbonate to the sodium hydroxide to the water is 3.5-8.0: 1: 25-40;

(4) preparation of the catalyst

Adding A, B solution into the suspension obtained in the step (1) under the condition of stirring, controlling the pH value in the whole precipitation process to be 7-8, controlling the precipitation time to be 1-3h, and after the precipitation process is finished; keeping stirring for 4-8h at 60-90 ℃ and carrying out an aging process; and finally, filtering, washing with water, drying, roasting, tabletting and forming the formed precipitate to obtain the catalyst for producing the 1, 6-hexanediol by hydrogenating the adipate.

4. The process for preparing a catalyst for the hydrogenation of adipate to produce 1, 6-hexanediol according to claim 3, characterized in that:

The water washing process requires that the filtrate be washed to neutrality or no Na is detected in the filtrate⁺as a benchmark; the drying temperature is selected from 80-the temperature is 120 ℃, and the time is 9-14 h; the temperature of the roasting process is raised to 450-500 ℃ at the temperature rising rate of 5-10 ℃/min, and then the roasting is carried out for 2-4 h.

Technical Field

The invention relates to the field of hydrogenation catalytic synthesis, and relates to a catalyst for producing 1, 6-hexanediol by adipate hydrogenation and a preparation method thereof.

Background

1, 6-hexanediol (1, 6-HDO) is a new fine chemical raw material with high added value polyester, has unique performance, can be mixed with organic chemicals in any proportion to derive a series of novel high-end fine chemicals, and is called as organic synthesis new basestones. 1, 6-hexanediol is an environment-friendly chemical raw material, has wide application range, has great application potential and commercial value in the application fields of high-performance polyurethane, UV coating, high-added-value polyester, environment-friendly coating, biodegradation, medicine, dye and the like, and the water resistance, the mechanical strength, the oxidation resistance and the environment friendliness of the resin, the coating and the like modified by the 1, 6-hexanediol are all improved. With the increasing of the domestic 1, 6-hexanediol production capacity and the improvement of the consumption level, the application range of the 1, 6-hexanediol is continuously expanded.

chinese patent CN1158234C discloses a catalyst for preparing 1, 6-hexanediol by hydrogenation of dimethyl adipate, the active component of the catalyst is preferably copper, cobalt or rhenium, the catalyst can be only composed of the active component or the active component is coated on a carrier, the carrier comprises Cr₂O₃、SiO₂ZrO, BaO and MgO or mixtures thereof. In the embodiment, the reaction pressure is 22-25MPa, the conditions are harsh, the pressure requirement on equipment is increased, the investment cost is increased, and the danger is increased.

Chinese patent CN1594252A discloses the preparation of dimethyl adipate from adipic acid through high pressure esterification and separation. Then dimethyl adipate is taken as a raw material, a composite oxide containing Ni, Cu and A1 is taken as a catalyst carrier, noble metals such as loaded Pt, Pd Ru and the like are taken as catalyst active components to prepare a solid supported catalyst, and the 1, 6-hexanediol is prepared by catalytic hydrogenation. The reaction was carried out at 210 ℃ under a pressure of 2.5MPa and at a space velocity of 0.56 h-1. The noble metal catalyst used is relatively costly. The three-component catalyst disclosed in Chinese patent CN101138726A, the four-component catalyst disclosed in CN1565729A and the five-component copper-based catalyst disclosed in CN109748778A are used for preparing 1, 6-hexanediol by hydrogenating dimethyl adipate, and the obvious problem of a catalytic system is that the activity or selectivity at low temperature is poor, wherein the five-component catalyst is complex in composition and difficult to prepare. The copper-zinc-aluminum catalysts disclosed in patents CN101113128, CN108607562A, etc. and their excessive gold or rare earth metal modified catalysts can achieve high yield of 1, 6-hexanediol under conditions of high space velocity (> 0.5h-1), low hydrogen ester ratio (< 150) or low pressure (< 5MPa), but a large number of documents and patent experiments prove that the copper-zinc-aluminum or its derived improved catalysts can hardly achieve the conversion rate of dimethyl adipate greater than 99% and the selectivity of 1, 6-hexanediol greater than 97% under conditions of low pressure, high space velocity and low hydrogen ester ratio.

patent 201710236004.3 discloses a catalyst for producing 1, 6-hexanediol by hydrogenation of dimethyl adipate, which uses SiO with multi-stage pores₂the molecular sieve is used as a carrier to load a copper-based catalyst, and the gasified adipic acid dimethyl ester and hydrogen are mixed and then enter a fixed bed reactor to react under certain conditions to obtain a liquid-phase product containing 1, 6-hexanediol. Within 0.6-1.5h^-1The reaction activity is still kept higher under the space velocity of 3MPa, which is compared with the copper-zinc-aluminum and the derivative modified catalyst (the space velocity is generally 0.5 h)^-1Below), there is a greater lift. But the product 1, 6-hexanediol selectivity was less than 90%. In addition, the carrier needs expensive template agent F127 and tetraethyl silicate as raw material in the preparation process, the preparation method is complex and the cost is high.

Therefore, a more suitable catalyst for producing 1, 6-hexanediol by hydrogenating adipate is urgently needed to fill the blank of the prior art.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a catalyst for producing 1, 6-hexanediol by hydrogenating adipate and a preparation method thereof, wherein the 1, 6-hexanediol catalyst takes CuO as CuOThe main active component, ZnO as the assistant component, and Al modified by alkaline earth metal oxide₂O₃The material is a carrier, wherein, calculated by weight portion, CuO is 20-40 portions, ZnO is 30-60 portions, alkaline earth metal oxide comprises one or two of MgO, CaO and BaO, but not limited to, 5-25 portions, Al₂O₃5-20 parts. The catalyst has the advantages of adjustable active component composition and content, uniform active site distribution and simple preparation process; meanwhile, the catalyst has the conversion rate of dimethyl adipate as a raw material of more than 99.5% and the selectivity of 1, 6-hexanediol as a product of more than or equal to 98% at a relatively low temperature, and provides a great application prospect for producing 1, 6-hexanediol by hydrogenation of adipate.

Aiming at the prior technical situation in the field, the inventor provides the following specific technical scheme:

a catalyst for preparing 1, 6-hexanediol by hydrogenating adipate contains CuO as main active component, ZnO as assistant component and Al modified by alkaline-earth metal oxide₂O₃the material is a carrier;

More concretely, the CuO accounts for 20-40 parts by weight, the ZnO accounts for 30-60 parts by weight, the alkaline earth metal oxide accounts for 5-25 parts by weight, and the Al accounts for₂O₃5-20 parts;

Wherein the alkaline earth metal oxide includes but is not limited to one or two of MgO, CaO, BaO;

In the above components, the alkaline earth metal oxide may be deposited on the carrier, i.e., Al, during the coprecipitation of the precursors of the components₂O₃The surface is covered with Al₂O₃a part of acid sites, thereby realizing the reaction on Al₂O₃And (4) modifying.

CuO, ZnO and Al in the present invention₂O₃The precursor is selected as a reactant according to CuO, ZnO and Al₂O₃The addition amount of the precursor is calculated within the dosage range; wherein aluminum hydroxide dry glue and pseudo-boehmite are adopted as precursors, and high-purity Al can also be directly adopted₂O₃Powder, and modifying it with alkaline earth metal oxideCompared with other existing catalysts, the catalyst has better low-temperature reaction performance, which is a great characteristic of the application;

The precursors of CuO, ZnO and alkaline earth metal oxides can adopt the corresponding nitrates;

Besides, the inventor also provides a preparation method of the catalyst for producing 1, 6-hexanediol by hydrogenating adipate, which comprises the following specific steps:

(1)Al₂O₃Preparation of suspension

Weighing the formula amount of Al₂O₃Adding water into the powder or the precursor corresponding to the powder to prepare suspension, stirring and uniformly dispersing the suspension;

(2) Preparation of solution A

Weighing precursors corresponding to CuO, ZnO and alkaline earth metal oxides in a formula amount, mixing the precursors with water, and uniformly stirring to obtain a solution A;

(3) Preparation of solution B

And weighing sodium carbonate and sodium hydroxide, mixing with water and uniformly stirring to obtain a solution B. Wherein the mass ratio of the sodium carbonate to the sodium hydroxide to the water is 3.5-8.0: 1: 25-40;

(4) Preparation of the catalyst

adding A, B solution into the suspension obtained in the step (1) under the condition of stirring, controlling the pH value in the whole precipitation process to be 7-8, controlling the precipitation time to be 1-3h, and after the precipitation process is finished; keeping stirring for 4-8h at 60-90 ℃ and carrying out an aging process; finally, the formed precipitate is subjected to the steps of filtering, water washing, drying, roasting, tabletting and forming to obtain the catalyst for producing the 1, 6-hexanediol by hydrogenating the adipate;

wherein the water washing process requires the filtrate to be washed to neutrality or no Na is detected in the filtrate⁺as a benchmark; the drying temperature is 80-120 ℃ and the drying time is 9-14 h; the temperature of the roasting process is raised to 450-500 ℃ at the temperature rising rate of 5-10 ℃/min, then the roasting is carried out for 2-4h,

The solution B adopted in the preparation method is used as a precipitator, the acidic metal salt solution in the system is mainly neutralized in the precipitation process, the pH value of the whole system is controlled to be kept between 7 and 8, and metal ions are uniformly precipitated. The mixed precipitant can disperse active components more uniformly, has high thermal stability, and avoids the reduction of activity caused by sintering of copper oxide grains in the processes of roasting, reduction and reaction.

the catalyst obtained by the whole preparation process adopts aluminum hydroxide dry glue, pseudo-boehmite or Al₂O₃The powder is used as a precursor of a carrier, and a metal soluble salt solution is precipitated on the carrier in a form of cocurrent coprecipitation, wherein an active component CuO is mainly precipitated on ZnO and alkaline-earth metal oxide, but not on Al₂O₃on the carrier, compared with the catalyst prepared by adopting aluminum nitrate as a carrier precursor in the prior patent, the catalyst has the advantages of higher dispersity and thermal stability, higher sintering resistance of an active center in the roasting, reducing and reacting processes and the like; with Al₂O₃The carrier is modified by alkaline earth metal to ensure that the carrier has proper acid-base property, so that the generation of side reactions such as cracking, ester exchange reaction, cyclization and the like can be inhibited in the reaction process, the selectivity of a target product is improved, the yield of the final product is improved, and the material consumption and the energy consumption are reduced.

After obtaining the catalyst, the inventor also provides a specific application method thereof, which comprises the following specific steps:

The catalyst is filled by adopting a fixed bed, and hydrogen-nitrogen mixed gas (the hydrogen content is 10-100%) is required to be reduced before use under the condition of 250-300 ℃ for 5-8 h; the process conditions for producing 1, 6-hexanediol by hydrogenating adipate are as follows: 1L of catalyst is filled, the reaction temperature is 150-200 ℃, the reaction pressure is 5.0-7.0MPa, and the feeding airspeed of the raw material dimethyl adipate is 0.2-0.5h^-1the molar ratio of hydrogen to ester is 150-200.

Detailed Description

The present invention is further illustrated below with reference to examples, which will enable those skilled in the art to more fully understand the present invention, but which are not intended to limit the invention in any way;