CN102580732A - Catalyst for preparing 1, 4-cyclohexanedimethanol by catalyzing dimethyl terephthalate through one-step hydrogenation and preparation method of catalyst - Google Patents

Abstract

The invention discloses a catalyst for catalyzing the one-step hydrogenation of dimethyl terephthalate to prepare 1,4-cyclohexanedimethanol and a preparation method thereof, belonging to the technical field of catalyst preparation. The catalyst is a supported catalyst, and the active component is supported on the carrier Al ₂ O ₃ ; the active component is composed of three metals: ruthenium, platinum and tin. The preparation of the catalyst adopts co-impregnation method. The present invention only adopts a hydrogenation catalyst and a single reaction solvent to realize the preparation of 1,4-cyclohexanedimethanol through one-step hydrogenation of dimethyl terephthalate, and obtain a higher product yield, avoiding the The separation of intermediate products and the consumption of solvents reduce the consumption of energy resources in traditional processes.

Description

A catalyst for catalyzing the one-step hydrogenation of dimethyl terephthalate to prepare 1,4-cyclohexanedimethanol and its preparation method

technical field

The invention belongs to the technical field of catalyst preparation, in particular to a catalyst for catalyzing the one-step hydrogenation of dimethyl terephthalate to prepare 1,4-cyclohexanedimethanol and a preparation method thereof. the

Background technique

1,4-Cyclohexanedimethanol is a raw material monomer for the manufacture of polyester materials with excellent thermal stability and insulation, and has high industrial value. The current industrial production method of 1,4-cyclohexanedimethanol mainly uses dimethyl terephthalate as raw material to prepare 1,4-cyclohexane by hydrogenation of benzene ring and hydrogenation of ester group with two catalysts. dimethanol. Its disadvantage is that the process route is complex and requires a variety of reactors and reaction solvents, which is not conducive to reducing the consumption of energy resources. the

Contents of the invention

The present invention aims at the present situation of the current two-step production process of 1,4-cyclohexanedimethanol (using two kinds of hydrogenation catalysts respectively), and provides a method for catalyzing the one-step hydrogenation of dimethyl terephthalate to prepare 1,4-cyclohexanedimethanol. Catalyst for hexanedimethanol and process for its preparation. The invention only adopts one hydrogenation catalyst and a single reaction solvent to realize the one-step hydrogenation of dimethyl terephthalate to prepare 1,4-cyclohexanedimethanol, and obtain a higher product yield. the

The catalyst used to catalyze the one-step hydrogenation of dimethyl terephthalate to prepare 1,4-cyclohexanedimethanol described in _the present invention is a supported catalyst, and the active component is supported on the carrier _Al2O3 ; the active component Composed of three metals: ruthenium, platinum and tin; the mass percentage of ruthenium in the catalyst is 1-10%, preferably 3-8%, the mass percentage of platinum is 1-10%, preferably 2-8%, tin The mass percent content of the catalyst is 3-15%, preferably 4-12%; the particle size of the catalyst is 40-80 mesh.

The preparation of the above catalyst adopts co-impregnation method, and its specific operation process is: 0.025-0.20g of RuCl ₃ 3H ₂ O, 0.020-0.20g of H ₂ PtCl ₆ 6H ₂ O and 0.045-0.25g of SnCl ₂ . Dissolve 2H ₂ O in 1-4ml of deionized water, add 0.1-0.5ml of hydrochloric acid with a mass concentration of 20-35% to make a mixed solution, and then add 0.2-1.0g of carrier Al ₂ O ₃ with a particle size of 40-80 mesh Stir evenly in the above mixed solution, aging at room temperature for 10-20h; then vacuum-dry at 50-70°C for 8-15h; after drying, bake in air at 300-600°C for 4-10h, preferably 400-500°C; then add 10 - 40ml of water, and add sodium borohydride 0.1-0.5 times the mass of the roasted product for reduction, the reduction time is 1-3h; finally dry at 40-80°C for 8-12h in a nitrogen atmosphere for later use.

The above catalyst is applied to the one-step hydrogenation of dimethyl terephthalate to prepare 1,4-cyclohexanedimethanol, and the specific reaction conditions are: the reaction solvent is tetrahydrofuran, ethyl acetate or 1,4-epoxyhexane; The mass ratio of dimethyl terephthalate to the reaction solvent is 1: (15-40), preferably 1: (20-30); the above-mentioned catalyst consumption is 0.02-2.0% of the total mass of the reaction system, preferably 0.05-1.0 %; the reaction is carried out in a hydrogen atmosphere; the reaction process is divided into two stages, one stage reaction conditions: the reaction temperature is 120-200 ℃, preferably 140-190 ℃; the reaction pressure is 3-7MPa, preferably 4-6.5MPa; the reaction time is 1.0 -3.0h, preferably 1.5-3.5h; two-stage reaction conditions: the reaction temperature is 230-280°C, preferably 240-270°C; the reaction pressure is 7-9MPa, preferably 7.5-9MPa; the reaction time is 3.0-10.0h, preferably 5.0 -9.0h. the

The PuPtSn/Al ₂ O ₃ supported catalyst prepared by the invention realizes the one-step hydrogenation of dimethyl terephthalate as a raw material to prepare 1,4-cyclohexanedimethanol. The present invention only adopts a hydrogenation catalyst and a single reaction solvent to realize dimethyl terephthalate to prepare 1,4-cyclohexanedimethanol through one-step hydrogenation, and obtain a higher product yield, avoiding the The separation of intermediate products and the consumption of solvents reduce the consumption of energy resources in traditional processes.

Detailed ways:

【Implementation Example 1】

Dissolve 0.13g RuCl ₃ 3H ₂ O, 0.22g SnCl ₂ 2H ₂ O and 0.096g H ₂ PtCl ₆ 6H ₂ O in 2ml of deionized water, add 0.2ml of 35% hydrochloric acid until completely dissolved, Then add 1g of Al ₂ O ₃ with a particle size of 60-80 mesh, age at room temperature for 20 hours, dry at 60°C in vacuum for 12 hours, and then roast at 450°C in air for 8 hours; then add 20ml of water, add 0.5g of sodium borohydride for reduction, and after 2 hours Until no obvious bubbles are released; finally, dry it in a nitrogen atmosphere at 70°C for 10 hours for later use.

The active components of the prepared catalyst, ruthenium, tin and platinum, are loaded on _the carrier _Al2O3 , wherein the mass percentage of ruthenium is 5%, the mass percentage of platinum is 3.2%, and the mass percentage of tin is 11.7% %; Catalyst particle size is 60-80 mesh.

【Implementation Example 2】

Dissolve 0.13g RuCl ₃ 3H ₂ O, 0.22g SnCl ₂ 2H ₂ O and 0.13g H ₂ PtCl ₆ 6H ₂ O in 2ml of deionized water, add 0.2ml of 35% hydrochloric acid until completely dissolved, Then add 1g of Al ₂ O ₃ with a particle size of 40-60 mesh, age at room temperature for 20h, dry at 60°C for 12h in vacuum, and then roast at 450°C in air for 8h; then add 20ml of water, add 0.5g of sodium borohydride for reduction, and after 2h Until no obvious bubbles are released; finally, dry it in a nitrogen atmosphere at 70°C for 10 hours for later use.

The active components of the prepared catalyst, ruthenium, tin and platinum, are loaded on _the carrier _Al2O3 , wherein the mass percentage of ruthenium is 5%, the mass percentage of platinum is 4.8%, and the mass percentage of tin is 11.7% %; Catalyst particle size is 40-60 mesh.

【Implementation Example 3】

Dissolve 0.13g RuCl ₃ 3H ₂ O, 0.22g SnCl ₂ 2H ₂ O and 0.19g H ₂ PtCl ₆ 6H ₂ O in 2ml of deionized water, add 0.2ml of 35% hydrochloric acid until completely dissolved , then add 1g of Al ₂ O ₃ with a particle size of 40-80 mesh, aging at room temperature for 20h, drying in vacuum at 60°C for 12h, and then roasting in air at 450°C for 8h; then add 20ml of water, add 0.5g of sodium borohydride for reduction, 2h Finally, until no obvious bubbles are released; finally, dry it in a nitrogen atmosphere at 70°C for 10 hours for later use.

The active components of the prepared catalyst, ruthenium, tin and platinum, are loaded on _the carrier _Al2O3 , wherein the mass percentage of ruthenium is 5%, the mass percentage of platinum is 7.2%, and the mass percentage of tin is 11.7% %; Catalyst particle size is 40-80 mesh.

The catalyst prepared by the above-mentioned examples 1, 2, and 3 is applied to the reaction of preparing 1,4-cyclohexanedimethanol by one-step hydrogenation of dimethyl terephthalate, and the specific reaction conditions are: 45g tetrahydrofuran is used as solvent and 1g p-benzene Dimethyl diformate is placed in a 250ml autoclave, and 0.3g of the catalyst prepared in Example 1, 2 or 3 is added. After the autoclave is closed, the air is replaced three times with nitrogen, and then the nitrogen is replaced three times with hydrogen; start heating at a hydrogen pressure of 3MPa Stir until the reaction temperature is 180°C, then adjust the reaction pressure to 6MPa, raise the temperature to 260°C after two hours, adjust the pressure to 8.5MPa, react under these conditions for 8 hours, and stop the reaction. The reaction result is as follows:

Using the catalyst prepared in Example 1 to carry out the conversion rate of hydrogenation reaction is 97.1%, and the yield of target product 1,4-cyclohexanedimethanol is 53.2%;

Using the catalyst prepared in Example 2 to carry out the conversion rate of hydrogenation reaction is 98.2%, and the yield of target product 1,4-cyclohexanedimethanol is 75.1%;

The conversion rate of the hydrogenation reaction using the catalyst prepared in Example 3 was 98.2%, and the yield of the target product 1,4-cyclohexanedimethanol was 64.6%. the

Claims (7)

1. A catalyst for preparing 1,4-cyclohexanedimethanol by catalyzing the one-step hydrogenation of dimethyl terephthalate, characterized in that the catalyst is a supported catalyst, and the active component is loaded on a carrier Al ₂ O _3. The active component is composed of three metals, ruthenium, platinum and tin; the mass percentage of ruthenium in the catalyst is 1-10%, the mass percentage of platinum is 1-10%, and the mass percentage of tin is 3-15%; the particle size of the catalyst is 40-80 mesh. 2. catalyzer according to claim 1 is characterized in that, the mass percent composition of ruthenium is 3-8% in the catalyzer, and the mass percent composition of platinum is 2-8%, and the mass percent composition of tin is 4-8%. 12%. 3. The method for preparing the catalyst as claimed in claim 1 or 2, characterized in that, it is prepared by a co-impregnation method, and its specific operation process is: 0.025-0.20g of RuCl ₃ 3H ₂ O, 0.020-0.20g of RuCl 3 . Dissolve H ₂ PtCl ₆ ·6H ₂ O and 0.045-0.25g of SnCl ₂ ·2H ₂ O in 1-4ml of deionized water, add 0.1-0.5ml of hydrochloric acid with a mass concentration of 20-35% to form a mixed solution, and then Add 0.2-1.0g carrier Al ₂ O ₃ with a particle size of 40-80 mesh into the above mixed solution and stir evenly, aging at room temperature for 10-20h; then vacuum-drying at 50-70°C for 8-15h; Roast at 600°C for 4-10h, preferably 400-500°C; then add 10-40ml of water, and add 0.1-0.5 times the mass of the roasted product with sodium borohydride for reduction, the reduction time is 1-3h; finally at 40-80 ℃ dry in nitrogen atmosphere for 6-12h for later use. 4. according to the application of claim 1 or 2 described catalysts, it is characterized in that, it is applied to dimethyl terephthalate one-step hydrogenation and prepares 1,4-cyclohexanedimethanol reaction, and concrete reaction condition is: The reaction solvent is tetrahydrofuran, ethyl acetate or 1,4-epoxyhexane; the mass ratio of dimethyl terephthalate and the reaction solvent is 1: (15-40); the consumption of the catalyst described in claim 1 or 2 It is 0.02-2.0% of the total mass of the reaction system; the reaction is carried out in a hydrogen atmosphere; the reaction process is divided into two stages, and the reaction conditions of one stage: the reaction temperature is 120-200°C, the reaction pressure is 3-7MPa, and the reaction time is 1.0-3.0h , Two-stage reaction conditions: the reaction temperature is 230-280°C, the reaction pressure is 7-9MPa, and the reaction time is 3.0-10.0h. 5. the application of catalyst according to claim 4, is characterized in that, the mass ratio of described dimethyl terephthalate and reaction solvent is 1: (20-30). 6. The application of the catalyst according to claim 4, characterized in that, the first-stage reaction conditions: the reaction temperature is 140-190°C, the reaction pressure is 4-6.5MPa, and the reaction time is 1.5-3.5h; the second-stage reaction Conditions: the reaction temperature is 240-270°C, the reaction pressure is 7.5-9MPa, and the reaction time is 5.0-9.0h. 7. The application of the catalyst according to claim 4, characterized in that the amount of the catalyst according to claim 1 or 2 is 0.05-1.0% of the total mass of the reaction system.