A method for preparing 1,4-cyclohexanedimethanol from waste polyester as raw material

Abstract

The invention discloses a method for preparing 1,4-cyclohexanedimethanol from waste polyester as raw material, the method first hydrogenates the benzene ring under the catalytic action of a loaded noble metal catalyst to obtain an intermediate product poly-1,4-cyclohexanedicarboxylic acid dibasic ester, the product of the first stage hydrogenation reaction is not separated and purified, and the second stage hydrogenation is directly carried out, and under the action of a copper-based catalyst, the ester group is reduced to an alcohol group to generate 1,4-cyclohexanedimethanol. The two-stage hydrogenation process uses the same reaction solvent and can be recycled, the waste polyester conversion rate reaches 100%, and the 1,4-cyclohexanedimethanol yield is up to 98%. The method has the characteristics of short process, few by-products, no intermediate product refining process and low energy consumption, can form a circulating process loop, and is suitable for large-scale production of 1,4-cyclohexanedimethanol.

Description

Technical Field

[0001] The invention relates to a method for producing 1,4-cyclohexanedimethanol, and in particular to a method for recycling and efficiently utilizing high molecular weight polymer polyester, and using waste polyester as a raw material to synthesize 1,4-cyclohexanedimethanol by two-step catalytic hydrogenation. Background Art

[0002] 1,4-cyclohexanedimethanol has a wide range of applications in polyester chemical industry. It is often used in the industry to synthesize modified polyesters. For example, 1,4-cyclohexanedimethanol is used to partially or completely replace ethylene glycol to prepare high-performance polyethylene terephthalate cyclohexanedimethanol. The addition of 1,4-cyclohexanedimethanol is beneficial to reduce the crystallization rate of the generated copolymer and improve its mechanical properties. This is mainly because 1,4-cyclohexanedimethanol has a highly symmetrical structure and its primary alcohol group has no steric hindrance, which makes it easy to approach the cross-linking agent and obtain the polymer in a shorter time, making the chain arrangement of the prepared saturated polyester resin more compact and improving the hardness of the saturated polyester resin. Therefore, the resin modified with 1,4-cyclohexanedimethanol has better properties, such as high melting point, high hardness, good physical processability, and good hydrolysis stability. At present, 1,4-cyclohexanedimethanol has been widely used to replace ethylene glycol or other alcohols to synthesize high-performance polyesters with excellent properties such as high strength, high thermal stability and acid and alkali resistance, and is widely used in food, electrical appliances, daily chemicals and other industries. At present, the world's largest producer of 1,4-cyclohexanedimethanol is Eastman Company of the United States, but they monopolize the production technology of 1,4-cyclohexanedimethanol, and the 1,4-cyclohexanedimethanol they produce is mainly for self-use, and restricts external sales, which seriously hinders the development and innovation of my country's polyester new materials industry.

[0003] At present, there are six methods for preparing 1,4-cyclohexanedimethanol according to different raw materials: (1) dibasic terephthalate route. In industry, dimethyl terephthalate (DMT) is usually used as a raw material and is hydrogenated in two steps. First, a noble metal catalyst is used to hydrogenate its benzene ring to prepare dimethyl 1,4-cyclohexanedicarboxylate, and then a copper-based catalyst is used to hydrogenate its ester to generate 1,4-cyclohexanedimethanol, such as the technical methods disclosed in patents CN 1099744A, CN 1223631A, US 6187968B1, CN105688915B and CN 110437033A. In order to simplify the process, Kailing Chemical Company proposed in patent CN105688915B to use DMT as raw material, 10-60% (mass ratio) of copper oxide, 10-60% (mass ratio) of nickel oxide, 28-80% (mass ratio) of carrier and 0-2% of additive (ZnO or MnO 2) is used to prepare 1,4-cyclohexanedimethanol by a one-pot two-step hydrogenation method. The DMT conversion rate is as high as 99.9%, and the selectivity of 1,4-cyclohexanedimethanol is about 98%. Patent CN 113248346A proposes to use a physically mixed palladium-based and copper-based catalyst in a 1,4-dioxane solvent to catalyze the hydrogenation reaction of dimethyl terephthalate to prepare 1,4-cyclohexanedimethanol by a one-pot method. The conversion rate of DMT reaches 100%, and the CHDM yield reaches more than 91%. Patent CN 106518608A proposes to use dibutyl terephthalate as a raw material, and use a precious metal-supported catalyst and a transition metal oxide catalyst to carry out two-stage hydrogenation to prepare 1,4-cyclohexanedimethanol. Due to the high prices of DMT and dibutyl terephthalate raw materials, their large-scale production is limited. (2) Terephthalic acid route. Jiangsu Hengxiang Chemical Company uses terephthalic acid as raw material in patent CN 105237341A, and conducts a hydrogenation reaction in methanol solvent with Pd / C as catalyst. After the reaction is complete, the 1.4-cyclohexanedicarboxylic acid is obtained in a hydrogen atmosphere and heated to 400 ℃ in a Cu-Zn-Al- 2 O 3Under the action of the catalyst, a two-stage hydrogenation reaction occurs in a methanol solvent. After the reaction is complete, the 1,4-cyclohexanedimethanol is obtained through post-treatment. The yield of 1,4-cyclohexane reaches more than 85% and the purity reaches more than 99.9%. Patent CN104549494B proposes to use terephthalic acid as a raw material and a Pt-Ru-Sn / C catalyst as a co-catalyst to directly hydrogenate 1,4-cyclohexanedimethanol in a one-step method. The yield of 1,4-cyclohexanedimethanol is as high as 86%. Since terephthalic acid and cyclohexanedicarboxylic acid are acidic under high temperature conditions, the equipment requirements are relatively high. At the same time, the hydrogenation of carboxyl groups is relatively difficult. At present, this method is still in the laboratory development stage. (3) Cyclohexanedicarboxylic acid dibasic ester route. Patent CN114436770A uses cyclohexanedicarboxylic acid dibasic ester as raw material and a supported copper-based catalyst to carry out catalytic hydrogenation in a hydrogen atmosphere at 200-250°C to prepare a high proportion of cis-1,4-cyclohexanedimethanol. Patent CN 102381938B and Patent CN 105582961 B also use the same route. (4) 1,4-cyclohexanedicarboxylic acid route. Patent CN 114436772B proposes to hydrogenate 1,4-cyclohexanedicarboxylic acid over a Ru-Pd-Sn / C catalyst to obtain the product 1,4-cyclohexanedimethanol, with a 1,4-cyclohexanedicarboxylic acid conversion rate of more than 99.5%, and the yield of the product 1,4-cyclohexanedimethanol can be stabilized at more than 98.5%. CNPC has also applied for a series of related patents, such as CN 109305886B, CN 109304167B and CN 109304166B. (5) Biomass route. Wanhua Chemical proposed in patent CN 108083978A to use bio-based raw material muconic acid as raw material to prepare 1,4-cyclohexanedimethanol through esterification, Diels–Alder reaction and hydrogenation reaction. This route reduces the use of petrochemical resources and has a high reaction yield, but the operation is complicated. (6) Waste polyester route. Patent CN 115340445A proposes to firstly alcoholize waste polyesters, such as polyethylene terephthalate (PET), polypropylene terephthalate (PTT), polybutylene terephthalate (PBT), etc., in methanol solvent to generate dimethyl terephthalate, and then utilize the synergistic coupling of the active sites of ruthenium-based catalysts and copper-based catalysts to selectively hydrogenate the benzene rings at 30-60°C to generate 1,4-cyclohexane dimethyl ester, and finally heat to 180-220°C to hydrogenate the methyl formate functional group to generate the target product 1,4-cyclohexanedimethanol. The highest conversion rate of waste polyester substrate is 99%, and the highest yield of 1,4-cyclohexanedimethanol is 98%. This method has a high product yield, but the method is divided into three steps, the process is complicated, and the reaction pressure of the methanol alcoholysis process is high, which limits its industrial production.

[0004] Polyesters such as polyethylene terephthalate (PET), polypropylene terephthalate (PTT) and polybutylene terephthalate (PBT) are mainly used to prepare fibers, films, bottling materials, etc. In recent years, my country's PET production has grown steadily, reaching 50.69 million tons in 2018. However, due to the strong chemical inertness of waste polyester materials, they are not easily degraded by air or microorganisms in a short period of time, resulting in the production of a large amount of waste polyester, which has put tremendous pressure on the protection of the social ecological environment. Therefore, in recent years, the recycling and resource reuse of waste polyester has received more and more attention. Since polyesters such as PET, PTT, and PBT contain terephthalic acid structural units, they can be used as raw materials for the synthesis of high-value-added 1,4-cyclohexanedimethanol.

[0005] As mentioned above, there is no report on directly using waste polyester as raw material to produce 1,4-cyclohexanedimethanol by two-step hydrogenation. The present invention proposes to use waste polyester as raw material to carry out two-step catalytic hydrogenation to prepare high value-added product 1,4-cyclohexanedimethanol, and the intermediate product does not need to be separated, the steps are simple, the raw materials are cheap and easy to obtain, the atomic utilization rate is high, and the clean and efficient utilization of waste resources is effectively realized, which has important strategic significance for sustainable development, resource recycling and environmental protection, and has good industrial application prospects. Summary of the invention

[0006] The present invention provides a method for preparing 1,4-cyclohexanedimethanol using waste polyester as raw material. The waste polyester conversion rate is greater than 99%, and the yield of 1,4-cyclohexanedimethanol reaches 98%. The method has cheap and readily available raw materials, a simple process flow, is environmentally friendly, has high atomic utilization, avoids complex intermediate product separation steps, and has a high yield (98%) and high purity (99.9%) of 1,4-cyclohexanedimethanol, effectively realizing clean and efficient utilization of waste resources, and has good industrial application prospects.

[0007] The technical solution of the present invention is as follows:

[0008] A method for preparing 1,4-cyclohexanedimethanol using waste polyester as raw material, comprising the following steps:

[0009] (1) adding polyester, organic solvent and noble metal catalyst into a first stage hydrogenation reactor at the same time, carrying out liquid phase hydrogenation reaction under hydrogen atmosphere, and filtering and removing the noble metal catalyst after the reaction is completed to obtain an organic solution of poly(1,4-cyclohexanedicarboxylic acid diester);

[0010] (2) the organic solution of poly(1,4-cyclohexanedicarboxylic acid diol) obtained in step (1) is directly introduced into a second-stage hydrogenation reactor, and liquid-phase or gas-phase hydrogenation is performed in a hydrogen atmosphere under the action of a copper-based catalyst to generate an organic solution of 1,4-cyclohexanedimethanol;

[0011] (3) The organic solution of 1,4-cyclohexanedimethanol obtained in step (2) enters a distillation tower for separation to obtain an organic solvent and 1,4-cyclohexanedimethanol respectively. The organic solvent is recycled and then enters the first stage hydrogenation reactor.

[0012] The reaction equation involved in the present invention is as follows:

[0013]

[0014] The present invention uses waste polyester as raw material for the first time, and in the same organic solvent, respectively, under the action of a supported noble metal catalyst and a copper-based catalyst, sequentially undergoes two-stage hydrogenation to achieve efficient preparation of 1,4-cyclohexanedimethanol.

[0015] Preferably, in step (1), the waste polyester includes one or a mixture of two or more of polyethylene terephthalate (PET), polypropylene terephthalate (PBT), and polybutylene terephthalate (PTT).

[0016] Preferably, in step (1), the supported noble metal catalyst comprises a carrier and an active component supported on the carrier, wherein the active component is one or two or more of Pd, Ru, Rh and Pt, and the carrier is selected from SiO 2 、TiO 2 、Al 2 O 3 、MnO 2 As a further preferred embodiment, the active component is Ru and the carrier is Al 2 O 3 Or activated carbon.

[0017] Preferably, in step (1), based on the total weight of the supported noble metal catalyst, the content of the active component is 0.05 to 10% (mass percentage), preferably 0.3 to 5% (mass percentage).

[0018] Preferably, in step (1), during the first hydrogenation process, the mass concentration of the polyester in the organic solvent is 1wt% to 100wt%, preferably 5wt% to 50wt%, the mass ratio of the supported noble metal catalyst to the polyester is 1:50 to 1:1, preferably 1:20 to 1:1, the hydrogen partial pressure is 1.0 to 8.0 MPa, preferably 2.0 to 6.0 MPa, the reaction temperature is 140 to 240°C, preferably 150 to 240°C, and the reaction time is 0.5 to 24 hours, preferably 1 to 12 hours;

[0019] Preferably, in step (1), the organic solvent is one of isopropanol, butanol, pentanol, cyclohexane, ethyl acetate, octane, heptane, nonane, ethylene glycol dimethyl ether, 1,4-dioxane, decahydronaphthalene, or a mixture of two or more thereof.

[0020] Preferably, in step (2), the copper-based catalyst comprises a carrier and Cu and an additive supported on the carrier, wherein the additive is at least one of oxides of Co, Zn, Mn, Ni, and Cr, and the carrier is Al 2 O 3 、ZrO 2 ,MgO,TiO 2 、SiO 2 、CeO 2 As a further preference, the copper-based catalyst promoter is at least one of Zn, Mn or Ni oxides, and the carrier is Al 2 O 3 、CeO 2 Or at least one of MgO.

[0021] Preferably, in step (2), based on the total weight of the multi-component copper-based catalyst, the content of Cu in the catalyst is 10 to 55% by weight, the content of the additive in the catalyst is 5 to 75% by weight, and the content of the carrier in the catalyst is 0 to 60% by weight.

[0022] In step (2), when the second stage hydrogenation is gas phase hydrogenation, the reaction temperature is 200-300°C, preferably 210-280°C, the hydrogen partial pressure is 1.0-8.0 MPa, preferably 2.0-6.0 MPa, H 2 The molar ratio of the polyester (the amount of the substance calculated according to the repeating unit) is 2 to 200, preferably 5 to 100, and the feed mass space velocity of the polyethylene 1,4-cyclohexanedicarboxylate is 0.01 to 5.0 h -1 , preferably 0.05~2.0h -1 .

[0023] Preferably, in step (2), when the second stage hydrogenation adopts liquid phase hydrogenation, the reaction temperature is 200-300° C., preferably 210-280° C., the hydrogen partial pressure is 1.0-8.0 MPa, preferably 2.0-6.0 MPa, the mass concentration of the first stage hydrogenation product poly (1,4-cyclohexanedicarboxylic acid dibasic ester) in the organic solvent is 1-100wt%, the mass ratio of the copper-based catalyst to the polyester in the second stage hydrogenation is 1:50-3:1, and the reaction time is 0.5-24 hours.

[0024] Preferably, the separation is achieved by vacuum distillation with a vacuum degree of 1 to 100 KPa and a temperature of 50 to 300°C.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention adopts waste polyester as raw material for the first time, and performs two-step catalytic hydrogenation in the same organic solvent to prepare 1,4-cyclohexanedimethanol. The characteristics of noble metal catalyst catalyzing benzene ring hydrogenation and copper-based catalyst catalyzing ester group hydrogenation are respectively utilized to directly convert waste polyester into high value-added 1,4-cyclohexanedimethanol in the same organic solvent. Within the measured condition range, the conversion rate of waste polyester reaches 100%, and the yield of 1,4-cyclohexanedimethanol is up to 98%. The method is easy to operate, the process is simple, the raw materials are cheap and easy to obtain, the separation of intermediate products is avoided, the solvent can be recycled, the cost is low, the product 1,4-cyclohexanedimethanol has high added value, and the efficient utilization of waste polyester is realized. It has the prospect of large-scale application and has important strategic significance for environmental protection, efficient utilization of resources and sustainable social development. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0028] The following examples are used to illustrate the specific implementation of the present invention and further illustrate the present invention. Moreover, the present invention is not limited to the following examples. Without departing from the technical scope of the previous and subsequent embodiments, the variations are all included in the technical scope of the present invention.

[0029] Example 1.

[0030] 5%Ru / TiO 2 Catalyst preparation: Take 1.37g RuCl 3 and 200 mL of deionized water were placed in a 500 mL beaker and stirred until completely dissolved. Then 10 g of TiO 2 The two solutions were dispersed in 100 mL of deionized water, mixed, and stirred continuously at 60 ° C for 24 h. The solvent was evaporated and then dried in an oven at 90 ° C for 24 h. After that, the powder was calcined at 400 ° C for 4 h in a nitrogen atmosphere. After cooling, the powder was reduced at 250 ° C for 2 h in a tube furnace under a mixed atmosphere of hydrogen and nitrogen to obtain 5% Ru / TiO 2 catalyst.

[0031] Example 2.

[0032] 5%Ru / MnO 2 Preparation of catalyst: 10 g TiO 2 ” is replaced by “10gMnO 2 The rest of the operation is the same as in Example 1 to obtain 5%Ru / MnO 2catalyst.

[0033] Example 3.

[0034] 5%Ru / γ-Al 2 O 3 Preparation of catalyst: 10 g TiO 2 " is replaced by "10gγ-Al 2 O 3 The rest of the operation is the same as in Example 1 to obtain 5%Ru / γ-Al 2 O 3 catalyst.

[0035] Example 4.

[0036] 5%Ru / SiO 2 Preparation of catalyst: 10 g TiO 2 ” is replaced by “10gSiO 2 The rest of the operation is the same as in Example 1 to obtain 5%Ru / SiO 2 catalyst.

[0037] Example 5.

[0038] 7%Ru / γ-Al 2 O 3 Catalyst preparation: Take 1.95g RuCl 3 and 200mL of deionized water were placed in a 500mL beaker and stirred until completely dissolved. Then 10g of γ-Al 2 O 3 The two solutions were dispersed in 100 mL of deionized water, mixed, and stirred continuously at 60 ° C for 24 h, the solvent was evaporated, and then dried in an oven at 90 ° C for 24 h, calcined at 400 ° C for 4 h in an air atmosphere, and the powder obtained after cooling was reduced at 250 ° C for 2 h in a tube furnace under a mixed atmosphere of hydrogen and nitrogen to obtain 7% Ru / γ-Al 2 O 3 catalyst.

[0039] Example 6.

[0040] 10%Ru / γ-Al 2 O 3 Preparation of catalyst: 1.95 g RuCl 3 ” is replaced by “2.88gRuCl 3 The remaining operations were the same as in Example 5 to obtain 10% Ru / γ-Al 2 O 3 catalyst.

[0041] Example 7.

[0042] 3%Ru / γ-Al 2 O 3 Preparation of catalyst: 1.95 g RuCl 3 ” is replaced by “0.80gRuCl 3 The remaining operations were the same as in Example 5 to obtain 3%Ru / γ-Al 2 O 3 catalyst.

[0043] Example 8

[0044] 1%Ru / γ-Al 2 O 3 Preparation of catalyst: 1.95 g RuCl 3 ” is replaced by “0.30gRuCl 3 The remaining operations were the same as in Example 5 to obtain 1%Ru / γ-Al 2 O 3 catalyst.

[0045] Example 9

[0046] 18wt%Cu-71wt%Mn 3 O 4 -Al 2 O 3 Preparation of catalyst: Take 56.3g (0.3mol) Cu(NO 3 ) 2 、258.3g(0.9mol)Mn(NO 3 ) 2 6H 2 O and 75 g (0.2 mol) Al(NO 3 ) 3 9H 2 O was completely dissolved in 600 mL of water, recorded as solution I, 128.0 g (3.2 mol) of NaOH was completely dissolved in 600 mL of water, recorded as solution II, then solution I and solution II were added dropwise into a 2000 mL three-necked flask with constant stirring, aged at 60 ° C for 12 h, dried in an oven (90 ° C) for 24 h, calcined at 600 ° C in an air furnace for 5 h, and finally reduced at 300 ° C for 2 h in a hydrogen / nitrogen (80 / 20 vol%) atmosphere to obtain 18 wt% Cu-71 wt% Mn 3 O 4 -Al 2 O 3 catalyst.

[0047] Example 10

[0048] 18wt%Cu-50wt%Mn 3 O 4 -Al 2 O 3 Catalyst preparation: Take 16.9 g (0.09 mol) Cu(NO 3 ) 2 、57.4g(0.2mol)Mn(NO 3 ) 2 6H 2 O and 75 g (0.2 mol) Al(NO 3 ) 3 9H 2 O was completely dissolved in 600 mL of water, recorded as solution I, 60.0 g (1.5 mol) of NaOH was completely dissolved in 600 mL of water, recorded as solution II, and then solution I and solution II were added dropwise to a 2000 mL three-necked flask with continuous stirring, aged at 60 ° C for 12 h, dried in an oven (90 ° C) for 24 h, calcined at 600 ° C in an air furnace for 5 hours, and finally reduced at 300 ° C for 2 h in a hydrogen / nitrogen (80 / 20 vol%) atmosphere to obtain 18 wt% Cu-50 wt% Mn 3 O 4 -Al 2 O 3 catalyst.

[0049] Embodiment 11

[0050] 18wt%Cu-23wt%Mn 3 O 4 -Al 2 O 3 Preparation of catalyst: Take 9.3g (0.05mol) Cu(NO 3 ) 2 、14.4g (0.05mol) Mn(NO 3 ) 2 6H 2 O and 75 g (0.2 mol) Al(NO 3 ) 3 9H 2 O was completely dissolved in 600 mL of water, recorded as solution I, 40.0 g (1.0 mol) of NaOH was completely dissolved in 600 mL of water, recorded as solution II, and then solution I and solution II were added dropwise into a 2000 mL three-necked flask with continuous stirring, aged at 60 ° C for 12 h, dried in an oven (90 ° C) for 24 h, calcined at 600 ° C in an air furnace for 5 h, and finally reduced at 300 ° C for 2 h in a hydrogen / nitrogen (80 / 20 vol%) atmosphere to obtain 18 wt% Cu-23 wt% Mn 3 O4 -Al 2 O 3 catalyst.

[0051] Example 12

[0052] 52wt%Cu-22wt%ZnO-Al 2 O 3 Preparation of catalyst: Take 56.3g (0.3mol) Cu(NO 3 ) 2 、29.8g (0.1mol) Zn(NO 3 ) 2 6H 2 O and 75.0 g (0.2 mol) Al(NO 3 ) 3 9H 2 O was completely dissolved in 600 mL of water, recorded as solution I, 64.0 g (1.6 mol) of NaOH was completely dissolved in 600 mL of water, recorded as solution II, and then solution I and solution II were added dropwise into a 2000 mL three-necked flask with continuous stirring, aged at 60 ° C for 12 h, dried in an oven (90 ° C) for 24 h, calcined at 600 ° C in an air furnace for 5 h, and finally reduced at 300 ° C for 2 h in a hydrogen / nitrogen (80 / 20 vol%) atmosphere to obtain 52 wt% Cu-22 wt% ZnO-Al 2 O 3 catalyst.

[0053] Embodiment 13

[0054] 52wt%Cu-22wt%ZnO-CeO 2 Preparation of catalyst: Take 50.6g (0.27mol) Cu(NO 3 ) 2 、26.8g (0.09mol) Zn(NO 3 ) 2 6H 2 O and 21.7 g (0.05 mol) Ce (NO 3 ) 3 6H 2O was completely dissolved in 600 mL of water, recorded as solution I, 40.0 g (1.0 mol) of NaOH was completely dissolved in 600 mL of water, recorded as solution II, and then solution I and solution II were added dropwise into a 2000 mL three-necked flask with continuous stirring, aged at 60 ° C for 12 h, dried in an oven (90 ° C) for 24 h, calcined at 600 ° C in an air furnace for 5 h, and finally reduced at 300 ° C for 2 h in a hydrogen / nitrogen (80 / 20 vol%) atmosphere to obtain 52 wt% Cu-22 wt% ZnO-CeO 2 catalyst.

[0055] Embodiment 14

[0056] 52wt%Cu-22wt%ZnO-ZrO 2 Catalyst preparation: Take 36.6g (0.195mol) Cu(NO 3 ) 2 、20.8g (0.07mol) Zn(NO 3 ) 2 6H 2 O and 21.5 g (0.05 mol) Zr(NO 3 ) 4 ·5H 2 O was completely dissolved in 600 mL of water, recorded as solution I, 40.0 g (1.0 mol) of NaOH was completely dissolved in 600 mL of water, recorded as solution II, and then solution I and solution II were added dropwise into a 2000 mL three-necked flask with continuous stirring, aged at 60 ° C for 12 h, dried in an oven (90 ° C) for 24 h, calcined at 600 ° C in an air furnace for 5 h, and finally reduced at 300 ° C for 2 h in a hydrogen / nitrogen (80 / 20 vol%) atmosphere to obtain 52 wt% Cu-22 wt% ZnO-ZrO 2 catalyst.

[0057] Embodiment 15

[0058] Preparation of 29wt%Cu-34wt%NiO-MgO catalyst: 18.7g (0.1mol) Cu(NO 3 ) 2 、29.1g(0.1mol)Ni(NO 3 ) 2 6H 2 O and 51.2 g (0.2 mol) Mg(NO 3 ) 2 6H 2 O was completely dissolved in 600 mL of water, recorded as solution I, and 53.0 g (0.5 mol) of Na 2 CO 3All of them were dissolved in 600 mL of water, recorded as solution II, and then solution I and solution II were added dropwise into a 2000 mL three-necked flask with continuous stirring, aged at 60 ° C for 12 h, dried in an oven (90 ° C) for 24 h, calcined at 600 ° C in an air furnace for 5 hours, and finally reduced at 300 ° C for 2 h in a hydrogen / nitrogen (80 / 20 vol%) atmosphere to obtain a 29wt% Cu-34wt% NiO-MgO catalyst.

[0059] Example 16

[0060] 29wt%Cu-34%Cr 2 O 3 Preparation of -MgO catalyst: 18.7 g (0.1 mol) Cu(NO 3 ) 2 and 40.0 g (0.1 mol) Cr(NO 3 ) 3 9H 2 O was completely dissolved in 600 mL of water, recorded as solution I, 24.0 g (0.6 mol) of NaOH was completely dissolved in 600 mL of water, recorded as solution II, and then solution I and solution II were added dropwise to 200 mL of aqueous solution dispersed with 80 g (0.2 mol) of MgO and stirred continuously, aged at 60 ° C for 12 h, dried in an oven (90 ° C) for 24 h, calcined at 600 ° C in an air furnace for 5 h, and finally reduced at 300 ° C for 2 h in a hydrogen / nitrogen (80 / 20 vol%) atmosphere to obtain 29 wt% Cu-34% Cr 2 O 3 -MgO catalyst.

[0061] The catalysts prepared in Examples 1 to 16 are summarized in Table 1.

[0062] Table 1

[0063] Example 1 <![CDATA[5%Ru / TiO 2 ]]> Example 9 <![CDATA[18wt%Cu-71wt%Mn 3 A 4 Al 2 A 3 ]]> Example 2 <![CDATA[5%Ru / MnO 2 ]]> Example 10 <![CDATA[18wt%Cu-50wt%Mn 3 A 4 Al 2 A 3 <!-- 6 --> ]]> Example 3 <![CDATA[5%Ru / γ-Al 2 THE 3 ]]> Embodiment 11 <![CDATA[18wt%Cu-23wt%Mn 3 A 4 Al 2 A 3 ]]> Example 4 <![CDATA[5%Ru / SiO 2 ]]> Example 12 <![CDATA[52wt%Cu-22wt%ZnO-Al 2 THE 3 ]]> Example 5 <![CDATA[7%Ru / γ-Al 2 THE 3 ]]> Embodiment 13 <![CDATA[52wt%Cu-22wt%ZnO-CeO 2 ]]> Example 6 <![CDATA[10%Ru / γ-Al 2 THE 3 ]]> Embodiment 14 <![CDATA[52wt%Cu-22wt%ZnO-ZrO 2 ]]> Example 7 <![CDATA[3%Ru / γ-Al 2 THE 3 ]]> Embodiment 15 29wt%Cu-34wt%NiO-MgO Example 8 <![CDATA[1%Ru / γ-Al 2 THE 3 ]]> Example 16 <![CDATA[29wt%Cu-34wt%Cr 2 O 3 -MgO]]>

[0064] Application Example 1

[0065] Evaluation of the use of commercial 5% Pd / C catalyst and the catalyst prepared in Example 9 Waste polyethylene terephthalate (PET) was used as a raw material for hydrogenation to prepare 1,4-cyclohexanedimethanol. Specifically, 1 g of PET, 20 mL of isopropanol and 0.1 g of 5% Pd / C catalyst were placed in a 50 mL high-pressure reactor, replaced with high-purity hydrogen for 5 times, filled with hydrogen, and heating and stirring were started. The hydrogen partial pressure was maintained at 4.0 MPa, and the reaction was carried out at 140° C. for 8 h. After the reaction was completed, it was quickly cooled to room temperature, the catalyst was filtered, and the filtrate was taken and mixed with 0.2 g of 18 wt% Cu-71 wt% Mn 3 O 4 -Al2 O 3 The catalyst (prepared in Example 9) was put into a 50 mL reactor and reacted at 230° C. for 6 h under a hydrogen partial pressure of 4.0 MPa. After the reaction was completed, the mixture was cooled to room temperature, the catalyst was separated, and analyzed by gas chromatography. The experimental results are shown in Table 2.

[0066] Application Example 2

[0067] The "5% Pd / C catalyst" in Application Example 1 was replaced by "5% Pt / C catalyst", and the other operating conditions remained unchanged. The experimental results are shown in Table 2.

[0068] Application Example 3

[0069] The "5% Pd / C catalyst" in Application Example 1 was replaced by "5% Ru / C catalyst", and the other operating conditions remained unchanged. The experimental results are shown in Table 2.

[0070] Application Example 4

[0071] The "5% Pd / C catalyst" in Application Example 1 was replaced by "5% Rh / C catalyst", and the other operating conditions remained unchanged. The experimental results are shown in Table 1.

[0072] Application Example 5

[0073] The "5% Pd / C catalyst" in Application Example 1 was replaced with the "5% Ru / TiO 2 The other operating conditions remain unchanged. The experimental results are shown in Table 2.

[0074] Application Example 6

[0075] The "5% Pd / C catalyst" in Application Example 1 was replaced with the "5% Ru / MnO 2 The other operating conditions remain unchanged. The experimental results are shown in Table 2.

[0076] Application Example 7

[0077] The "5% Pd / C catalyst" in Application Example 1 was replaced with the "5% Ru / γ-Al 2 O 3 The other operating conditions remain unchanged. The experimental results are shown in Table 2.

[0078] Application Example 8

[0079] The "5% Pd / C catalyst" in Application Example 1 was replaced with the "5% Ru / SiO 2 The other operating conditions remain unchanged. The experimental results are shown in Table 2.

[0080] Application Example 9

[0081] The "5% Pd / C catalyst" in Application Example 1 was replaced with the "7% Ru / γ-Al 2 O 3 The other operating conditions remain unchanged. The experimental results are shown in Table 2.

[0082] Application Example 10

[0083] The "5% Pd / C catalyst" in Application Example 1 was replaced with the "10% Ru / γ-Al 2 O 3 The other operating conditions remain unchanged. The experimental results are shown in Table 2.

[0084] Application Example 11

[0085] The "5% Pd / C catalyst" in Application Example 1 was replaced with the "3% Ru / γ-Al 2 O 3 The other operating conditions remain unchanged. The experimental results are shown in Table 2.

[0086] Application Example 12

[0087] The "5% Pd / C catalyst" in Application Example 1 was replaced with the "1% Ru / γ-Al 2 O 3 The other operating conditions remain unchanged. The experimental results are shown in Table 2.

[0088] Table 2 Catalytic effects of different catalysts

[0089]

[0090] Application Example 13

[0091] The catalysts prepared in Examples 7 and 9 were used to evaluate the hydrogenation of PET to produce 1,4-cyclohexanedimethanol. Specifically, 5 g PET, 20 mL octane, 0.5 g 3% Ru / γ-Al 2 O 3 The catalyst (prepared in Example 7) was placed in a 50 mL autoclave, replaced with high-purity hydrogen for 5 times, filled with hydrogen, and heated and stirred. The hydrogen partial pressure was maintained at 3.0 MPa, and the reaction was carried out at 150° C. for 6 h. After the reaction was completed, the catalyst was quickly cooled to room temperature, the catalyst was filtered, and the filtrate was taken and mixed with 0.518 wt% Cu-71 wt% Mn 3 O 4 -Al 2 O 3The catalyst (prepared in Example 9) was put into a 50 mL reactor and reacted at 210° C. for 10 h under a hydrogen partial pressure of 3.0 MPa. After the reaction was completed, the mixture was cooled to room temperature, the catalyst was separated, and then analyzed by gas chromatography. The experimental results are shown in Table 3.

[0092] Application Example 14

[0093] The catalysts prepared in Examples 7 and 10 were used to evaluate the hydrogenation of PET to produce 1,4-cyclohexanedimethanol. 3 O 4 -Al 2 O 3 The catalyst was replaced with 18 wt% Cu-50 wt% Mn 3 O 4 -Al 2 O 3 The other operating conditions remain unchanged. The experimental results are shown in Table 3.

[0094] Application Example 15

[0095] The catalysts prepared in Examples 7 and 11 were used to evaluate the hydrogenation of PET to produce 1,4-cyclohexanedimethanol. 3 O 4 -Al 2 O 3 The catalyst was replaced with 18 wt% Cu-23 wt% Mn 3 O 4 -Al 2 O 3 The other operating conditions remain unchanged. The experimental results are shown in Table 3.

[0096] Application Example 16

[0097] The catalysts prepared in Examples 7 and 12 were used to evaluate the hydrogenation of PET to produce 1,4-cyclohexanedimethanol. Specifically, 3 g PET, 20 mL decahydronaphthalene, 1 g 3% Ru / γ-Al 2 O 3 The catalyst (prepared in Example 7) was placed in a 50 mL autoclave, replaced with high-purity hydrogen for 5 times, filled with hydrogen, and heated and stirred. The hydrogen partial pressure was maintained at 6.0 MPa. The reaction was carried out at 200°C for 3 h. After the reaction was completed, the reaction was rapidly cooled to room temperature. The catalyst was filtered and the filtrate was taken and mixed with 1 g 52 wt% Cu-22 wt% ZnO-Al 2 O 3The catalyst (prepared in Example 12) was put into a 50 mL reactor and reacted at 280° C. for 4 h under a hydrogen partial pressure of 6.0 MPa. After the reaction was completed, the mixture was cooled to room temperature, the catalyst was separated, and then analyzed by gas chromatography. The experimental results are shown in Table 3.

[0098] Application Example 17

[0099] The catalysts prepared in Examples 7 and 13 were used to evaluate the hydrogenation of PET to produce 1,4-cyclohexanedimethanol. 2 O 3 The catalyst was replaced with 52 wt% Cu-22 wt% ZnO-CeO prepared in Example 13. 2 The other operating conditions remain unchanged. The experimental results are shown in Table 3.

[0100] Application Example 18

[0101] The catalysts prepared in Examples 7 and 14 were used to evaluate the hydrogenation of PET to produce 1,4-cyclohexanedimethanol. 2 O 3 The catalyst was replaced with 52 wt% Cu-22 wt% ZnO-ZrO prepared in Example 14. 2 The other operating conditions remain unchanged. The experimental results are shown in Table 3.

[0102] Table 3

[0103]

[0104] Application Example 19 Experimental Study on Preparation of 1,4-Cyclohexanedimethanol by Catalytic Two-step Hydrogenation of Waste Polyester in Liquid Phase and Gas Phase

[0105] The catalyst prepared in Example 7 was used to evaluate the preparation of 1,4-cyclohexanedimethanol by two-step hydrogenation of PET in liquid phase and gas phase. Specifically, 5 g PET, 25 mL 1,4-dioxane, 0.5 g 3% Ru / γ-Al 2 O 3The catalyst was replaced with high-purity hydrogen for 5 times in a 50mL autoclave, and then filled with hydrogen. Heating and stirring were started, and the hydrogen partial pressure was maintained at 5.0MPa. The reaction was carried out at 240°C for 5h. After the reaction was completed, the catalyst was filtered and the filtrate was taken. 2g of 40-80 mesh 29wt% Cu-34wt% NiO-MgO catalyst (prepared in Example 15) was loaded into a fixed bed reactor. At 240°C and a hydrogen partial pressure of 5.0MPa, the above hydrogenation product (filtrate) was transported to the fixed bed by a pump. The molar ratio (hydrogen-ester ratio) of hydrogen to the initial raw material PET (calculated according to the PET repeating unit) was 30:1, and the mass space velocity of the feed was 0.3h -1 The reaction product was analyzed by gas chromatography, and the experimental results are shown in Table 4. Under the conditions of vacuum degree 5 KPa and temperature 170°C, the reaction product can be distilled to obtain 1,4-cyclohexanedimethanol with a purity of 99.9%.

[0106] Application Example 20 Experimental Study on Preparation of 1,4-cyclohexanedimethanol by Catalytic Two-step Hydrogenation of Waste Polyester in Liquid Phase and Gas Phase

[0107] The catalysts prepared in Examples 7 and 15 were used to evaluate the preparation of 1,4-cyclohexanedimethanol by two-step hydrogenation of PET in liquid phase and gas phase. Specifically, the molar ratio of hydrogen to the initial raw material PET (calculated according to the PET repeating unit) in Application Example 19 was 30:1, and the mass space velocity of the feed was 0.3h -1 ” is changed to “the molar ratio of hydrogen to the initial raw material PET (calculated according to the PET repeating unit) is 100:1, and the mass space velocity of the feed is 1.0h -1 ", the other operating conditions remain unchanged, and the experimental results are shown in Table 4. Under the conditions of vacuum degree 5KPa and temperature 170℃, the reaction product can be distilled to obtain 1,4-cyclohexanedimethanol with a purity of 99.7%.

[0108] Application Example 21 Experimental Study on Preparation of 1,4-cyclohexanedimethanol by Catalytic Two-step Hydrogenation of Waste Polyester in Liquid Phase and Gas Phase

[0109] The catalysts prepared in Example 7 and Example 15 were used to evaluate the preparation of 1,4-cyclohexanedimethanol by two-step hydrogenation of PET in liquid phase and gas phase. Specifically, the molar ratio of hydrogen to the initial raw material PET (calculated according to the PET repeating unit) in Application Example 19 was 30:1, and the mass space velocity of the feed was 0.3h -1 ” is changed to “the molar ratio of hydrogen to the initial raw material PET (calculated according to the PET repeating unit) is 10:1, and the mass space velocity of the feed is 0.1h -1 ", the other operating conditions remain unchanged, and the experimental results are shown in Table 4. Under the conditions of vacuum degree 5KPa and temperature 170℃, the reaction product can be distilled to obtain 1,4-cyclohexanedimethanol with a purity of 99.8%.

[0110] Application Example 22

[0111] The catalysts prepared in Example 7 and Example 16 were used to evaluate the preparation of 1,4-cyclohexanedimethanol by two-step hydrogenation of PET in liquid phase and gas phase. Specifically, the "29wt% Cu-34wt% NiO-MgO catalyst" in Application Example 19 was replaced with the "29wt% Cu-34wt% Cr 2 O 3 -MgO catalyst", and other operating conditions remain unchanged. The experimental results are shown in Table 4. Under the conditions of vacuum degree 5KPa and temperature 170℃, the reaction product can be distilled to obtain 1,4-cyclohexanedimethanol with a purity of 99.6%.

[0112] Application Example 23

[0113] The catalysts prepared in Example 7 and Example 15 were used to evaluate the preparation of 1,4-cyclohexanedimethanol by two-step hydrogenation of waste poly(trimethylene terephthalate) (PTT) in liquid phase and gas phase. Specifically, the raw material "5 g PET" in Application Example 19 was replaced with "5 g PTT", and the other operating conditions remained unchanged. The experimental results are shown in Table 4.

[0114] Application Example 24

[0115] The catalysts prepared in Example 7 and Example 15 were used to evaluate the preparation of 1,4-cyclohexanedimethanol by two-step hydrogenation of waste polybutylene terephthalate (PBT) in liquid phase and gas phase. Specifically, the raw material "5 g PET" in Application Example 19 was replaced with "5 g PBT", and the other operating conditions remained unchanged. The experimental results are shown in Table 4.

[0116] Application Example 25

[0117] The catalysts prepared in Example 7 and Example 15 were used to evaluate the preparation of 1,4-cyclohexanedimethanol by two-step hydrogenation of waste PET and PBT in liquid phase and gas phase. Specifically, the raw material "5 g PET" in Application Example 19 was replaced with "3 g PET and 2 g PBT", and the other operating conditions remained unchanged. The experimental results are shown in Table 4.

[0118] Table 4

[0119]

Claims

1. A method for preparing 1,4-cyclohexanedimethanol from waste polyester as raw material, characterized in that: Here are the steps: (1) adding polyester, organic solvent and noble metal catalyst into a first stage hydrogenation reactor at the same time, performing liquid phase hydrogenation reaction under hydrogen atmosphere, and filtering and removing the noble metal catalyst after the reaction is completed to obtain an organic solution of poly(1,4-cyclohexanedicarboxylic acid diester); (2) the organic solution of poly(1,4-cyclohexanedicarboxylic acid diol) obtained in step (1) is directly introduced into a second-stage hydrogenation reactor, and liquid-phase or gas-phase hydrogenation is performed in a hydrogen atmosphere under the action of a copper-based catalyst to generate an organic solution of 1,4-cyclohexanedimethanol; (3) The organic solution of 1,4-cyclohexanedimethanol obtained in step (2) enters a distillation tower for separation to obtain an organic solvent and 1,4-cyclohexanedimethanol, respectively, and the organic solvent enters the first stage hydrogenation reactor for recycling; In step (1), the mass concentration of the polyester in the organic solvent is 1 to 100 wt %, the mass ratio of the noble metal catalyst to the polyester is 1:50 to 1:1, the hydrogen partial pressure is 1.0 to 8.0 MPa, the reaction temperature is 140 to 240° C., and the reaction time is 0.5 to 24 hours; In step (1), the organic solvent is one or a mixture of isopropanol, butanol, pentanol, octane, heptane, nonane, 1,4-dioxane, and decahydronaphthalene; In step (1), the noble metal catalyst comprises a carrier and an active component supported on the carrier, the active component is one or both of Ru and Rh, and the carrier is selected from one or both of Al2O3 and activated carbon; In step (1), the content of the active component is 3 to 10 wt % based on the total weight of the noble metal catalyst; In step (2), the copper-based catalyst comprises a carrier and Cu and an additive loaded on the carrier, the additive is at least one of the oxides of Zn, Mn, and Ni, and the carrier is at least one of Al2O3, MgO, and CeO2.

2. The method for preparing 1,4-cyclohexanedimethanol from waste polyester as raw material according to claim 1, characterized in that: In step (1), the polyester is waste polyester, including one or a mixture of two or more of polyethylene terephthalate, polypropylene terephthalate, and polybutylene terephthalate.

3. The method for preparing 1,4-cyclohexanedimethanol from waste polyester as raw material according to claim 1, characterized in that: In step (2), based on the total weight of the copper-based catalyst, the content of Cu in the catalyst is 10-55%, the content of the auxiliary agent in the catalyst is 5-75%, and the content of the carrier in the catalyst is 0-60%.

4. The method for preparing 1,4-cyclohexanedimethanol from waste polyester as raw material according to claim 1, characterized in that: In step (2), when the second stage hydrogenation adopts gas phase hydrogenation, the reaction temperature is 200-300°C, the hydrogen partial pressure is 1.0-8.0 MPa, the molar ratio of H2 to polyester is 30-200:1, wherein the amount of the polyester is calculated according to the repeating unit; the mass space velocity of the poly-1,4-cyclohexanedicarboxylic acid dibasic ester feed is 0.01-5.0 h -1 .

5. The method for preparing 1,4-cyclohexanedimethanol from waste polyester as raw material according to claim 1, characterized in that: In step (2), when the second stage hydrogenation adopts liquid phase hydrogenation, the reaction temperature is 200-300° C., the hydrogen partial pressure is 1.0-8.0 MPa, the mass concentration of the poly 1,4-cyclohexanedicarboxylic acid dibasic ester is 1-100wt%, the mass ratio of the copper-based catalyst to the polyester is 1:50-3:1, and the reaction time is 0.5-24 hours.

6. The method for preparing 1,4-cyclohexanedimethanol from waste polyester as raw material according to claim 1, characterized in that: In step (3), the separation is achieved by vacuum distillation with a vacuum degree of 1 to 100 KPa and a temperature of 50 to 300°C.

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