Search

CN-122006772-A - Catalyst for synthesizing cyclohexanedimethanol by catalytic hydrogenation of crude terephthalic acid and preparation method thereof

CN122006772ACN 122006772 ACN122006772 ACN 122006772ACN-122006772-A

Abstract

The invention belongs to the field of chemical synthesis, and in particular relates to a catalyst for synthesizing cyclohexanedimethanol by catalytic hydrogenation of crude terephthalic acid and a preparation method thereof. The catalyst of the invention takes active carbon as a carrier to prepare the supported molybdenum nitride (MoN-AC) with high specific surface area. And then loading the metal active component on the surface of the catalyst, and activating to obtain the M/MoN-AC catalyst. Crude PTA containing p-carboxybenzaldehyde is used as a raw material, the prepared M/MoN-AC is used as a catalyst, and hydrogenation reaction is carried out in a proper solvent under proper temperature and hydrogen pressure, so that CHDM is synthesized efficiently. The CuRu/MoN-AC catalyst prepared by the invention has synergistic catalysis effect with MoN, and N element in MoN has dispersion and stabilization effects on CuRu active components, so that the catalyst has high catalysis effect and better stability, and is very beneficial to industrial application.

Inventors

  • HAN ZHAOXI
  • SHAN YUHUA
  • LIU PING
  • JIN LIUJUN
  • SU YICHUN

Assignees

  • 常州大学

Dates

Publication Date
20260512
Application Date
20260106

Claims (10)

  1. 1. A preparation method of the M/MoN-AC catalyst is characterized in that activated carbon is used as a carrier to prepare the supported molybdenum nitride MoN-AC with high specific surface area, then a metal active component is supported on the surface of the supported molybdenum nitride MoN-AC, and the metal active component is activated to obtain the M/MoN-AC catalyst.
  2. 2. The method for preparing the M/MoN-AC catalyst according to claim 1, wherein the preparation method of the supported molybdenum nitride MoN-AC comprises the steps of dissolving ammonium molybdate [ (NH 4 ) 6 Mo 7 O 24 ·4H 2 O ] in hot water to obtain an aqueous solution of ammonium molybdate, immersing AC, drying at 120 ℃ and 12: 12 h to obtain a precursor, then placing the precursor in a high-temperature furnace, and performing high-temperature treatment in an NH 3 atmosphere to obtain the MoN-AC with high specific surface area.
  3. 3. The preparation method of the M/MoN-AC catalyst according to claim 2, wherein the ammonium molybdate is used in an amount such that the mass ratio of Mo simple substance to AC in MoN-AC is 15-30..100, the weight ratio of water to AC is 3-5:1, the dissolution temperature and the impregnation temperature of ammonium molybdate in water are 60-90 ℃ and the impregnation time is 8-12 h.
  4. 4. The method for preparing the M/MoN-AC catalyst according to claim 2, wherein the precursor is placed in a high temperature furnace, and the high temperature treatment is performed in an NH 3 atmosphere at a temperature rising speed of 1-5 ℃ per minute to 650-750 ℃ for 3-6 hours.
  5. 5. The method for preparing the M/MoN-AC catalyst according to claim 1, wherein the method for preparing the M/MoN-AC catalyst is that the MoN-AC is impregnated with an aqueous solution of nitrate or acetate of Cu and Ru, then dried at 120 ℃ and 12 h, and subjected to high-temperature reduction and activation by hydrogen to obtain the catalyst CuRu/MoN-AC.
  6. 6. The method for preparing the M/MoN-AC catalyst according to claim 5, wherein the mass ratio of water used for impregnating MoN-AC to AC is 2 to 4..1, the weight ratio of the total weight of elemental cu and elemental Ru to AC is 10 to 16..100, and the weight ratio of elemental cu and elemental Ru is 1.0 to 2.0..1.0.
  7. 7. The method for preparing the M/MoN-AC catalyst according to claim 5, wherein the impregnation is carried out at room temperature for 6-12 hours, the method for high-temperature reduction and activation by hydrogen is carried out by heating to 250-400 ℃ at a heating rate of 2-5 ℃ per minute by using H 2 、N 2 mixed gas with a volume ratio of 1-4..10, and reducing for 2-5 hours.
  8. 8. An M/MoN-AC catalyst prepared according to the method of any one of claims 1-7.
  9. 9. Use of an M/MoN-AC catalyst prepared according to the process of any one of claims 1 to 7, characterized in that the M/MoN-AC catalyst is used for the catalytic hydrogenation of crude terephthalic acid in a solvent to cyclohexanedimethanol.
  10. 10. The application of the M/MoN-AC catalyst according to claim 9, wherein the solvent is methanol, ethanol, isopropanol or ethylene glycol methyl ether, ethylene glycol ethyl ether or ethylene glycol dimethyl ether, the mass ratio of the solvent to the crude PTA is 4-8..1, the mass ratio of the catalyst CuRu/MoN-AC to the crude PTA is 5-15:100, and the hydrogenation condition is 220-260 ℃ and 6.0-10.0 MPa H 2 .

Description

Catalyst for synthesizing cyclohexanedimethanol by catalytic hydrogenation of crude terephthalic acid and preparation method thereof Technical Field The invention belongs to the field of chemical synthesis, and in particular relates to a catalyst for synthesizing cyclohexanedimethanol by catalytic hydrogenation of crude terephthalic acid and a preparation method thereof. Background 1, 4-Cyclohexanedimethanol (CHDM) is an important chemical raw material, is a key monomer for producing high-melting-point, high-quality and high-impact-resistance polyester products, and is also an intermediate of paint, ink, adhesive, insulating materials and some unsaturated polyesters with special purposes, so the CHDM has great market requirements. The main preparation method of the CHDM comprises the following steps: 1. In the catalytic hydrogenation method of terephthalic acid ester, a two-stage catalytic hydrogenation technology is proposed in CN116444343, the first stage uses Ru/TiO 2 to catalyze PET hydrogenation to generate ethylene glycol cyclohexanedicarboxylate, and the second stage uses Cu/Mn 3O4-Al2O3 to catalyze hydrogenation to further generate CHDM, and the yield is 100%. In CN120571586, niCu/SiO 2 is used for catalyzing dimethyl terephthalate to synthesize CHDM through hydrogenation in one step, and the yield is 93%. 2. The catalytic hydrogenation method of commodity terephthalic acid (refined PTA) is proposed in CN117816154, and the commodity PTA is converted into CHDM by utilizing RuPd/C and CuZn/C composite catalysts to carry out two-stage hydrogenation at 2.5 MPa H 2, 170 ℃ and 230 ℃ and 8.0 MPa H 2 respectively, and the yield is 93.2%. WO 2015156582 also proposes the hydrogenation of commercial PTA with Pd/C and RuSnPt/C catalysts at 230℃and 8.0. 8.0 MPa H 2 to give CHDM in 85% yield. 3. In the catalytic hydrogenation method of terephthalyl alcohol, CN103878003 is proposed to catalyze terephthalyl alcohol by PdPt/NiMoP, and CHDM is obtained by hydrogenation under a mild condition of 100 ℃ and 1.5 MPa H 2, and the yield is 96.1%. 4. In the catalytic hydrogenation method of terephthalaldehyde, raney Ni is used as a catalyst in EP1099475, and under the conditions of 60 ℃ and 4.0 MPa H 2, the catalytic hydrogenation of terephthalaldehyde is carried out to obtain CHDM, and the yield is 89%. CHDM is a bulk chemical and has a market demand of millions of tons and is therefore sensitive to raw material costs. The 1 st, 3 rd and 4 th methods have high raw material cost, so that the product cost is high and the method has no competitiveness. The 2 nd method uses commercial PTA as raw material, the cost is relatively low, but the requirement on the catalyst is high, the catalyst depends on noble metal catalysis, and the operation condition is harsh. The main production technology of commodity PTA is that paraxylene is used as raw material, co-Mn-Br is used as catalyst, air or oxygen is used as oxidant, and oxidation reaction is carried out in acetic acid medium. The oxidized product is centrifugally separated to obtain solid crude PTA, and the crude PTA is subjected to Pd/C hydrofining, 5-level crystallization and water washing to obtain refined PTA. Crude PTA was about 99.5% pure, with p-carboxybenzaldehyde (4-CBA) as the major impurity. In order to remove about 0.3-0.4% of 4-CBA, the crude PTA is dissolved in pure water under the conditions of 286 ℃ and 7.6 MPa in engineering, pd/C catalytic hydrogenation is used to convert the 4-CBA into p-methylbenzoic acid (shown in formula 1), and then 5-level crystallization, press filtration and water washing are carried out to remove the p-methylbenzoic acid, so that refined PTA (commodity) with the purity of 99.98% is obtained. From the above-mentioned refining process, the crude PTA refining process is a process that is complicated in one process, high in energy consumption, generates a large amount of wastewater, consumes a noble metal catalyst, and is high in operation cost. Formula 1. Disclosure of Invention The invention aims to provide a novel catalytic technology, which directly uses crude PTA containing 4-CBA as a raw material, and the crude PTA is subjected to catalytic hydrogenation and is completely converted into a target product CHDM, so that the CHDM is produced at low cost. The reaction process is shown in formula 2. 2, 2 In order to achieve the aim, the invention adopts the technical scheme that coconut shell Activated Carbon (AC) is used as a carrier to prepare the load type molybdenum nitride (MoN-AC) with high specific surface area. And then loading the metal active component (M) on the surface of the catalyst, and activating to obtain the M/MoN-AC catalyst. Then, crude PTA containing 4-CBA is used as a raw material, and the prepared M/MoN-AC is used as a catalyst, and hydrogenation reaction is carried out in a proper solvent under proper temperature and hydrogen pressure control, so that CHDM is synthesized with high efficiency. The preparation method o