Hydrogenation method for preparing 1, 4-cyclohexane dicarboxylic acid diisooctyl ester from dioctyl terephthalate

Abstract

The invention relates to a hydrogenation method for preparing diisooctyl 1, 4-cyclohexanedicarboxylate from dioctyl terephthalate, which comprises the following steps: a dioctyl terephthalate solution is contacted with a selective hydrogenation catalyst for reaction to obtain a diisooctyl 1, 4-cyclohexanedicarboxylate product, the selective hydrogenation catalyst comprises a carrier, an active component and an auxiliary agent, the carrier is selected from one or more of MCM-41, SBA-15 and MCM-48, the active component is ruthenium, and the auxiliary agent is selected from one or more of cerium, lanthanum and titanium. According to the selective hydrogenation method provided by the invention, the conversion rate of the dioctyl terephthalate is high, and the selectivity of the obtained 1, 4-cyclohexane dicarboxylic acid diisooctyl ester is high.

Description

Technical Field

[0001] The invention relates to a method for preparing diisooctyl 1,4-cyclohexanedicarboxylate, in particular to a hydrogenation method for preparing diisooctyl 1,4-cyclohexanedicarboxylate from dioctyl terephthalate. Background Art

[0002] Dioctyl terephthalate (DOTP) is a phthalate plasticizer with excellent performance, mainly used in polyvinyl chloride plastic products. However, due to the presence of benzene rings, it is carcinogenic. A large number of animal experiments have also shown that long-term exposure to phthalate compounds can induce tumors. Therefore, phthalate plasticizers are gradually restricted or banned in many countries. Diisooctyl cyclohexanedicarboxylate prepared by hydrogenation reduction of DOTP is a low-toxic plasticizer with good thermal stability and antioxidant properties. It is widely used in plasticizers, cosmetics, advanced lubricants, etc. For example, it can be used as a valuable raw material for the preparation of jet engine advanced lubricants and lubricating esters. In addition, it is also used in chemical fiber oils. It has broad application prospects.

[0003] In the selective hydrogenation reaction of benzene ring, rhodium (Rh) has the best performance, but due to the high price of Rh, it will inevitably increase the cost of large-scale application. In contrast, ruthenium (Ru) has excellent performance in benzene ring hydrogenation and is cheaper than Rh, making it more suitable for large-scale application. Summary of the invention

[0004] The purpose of the present invention is to provide a hydrogenation method for preparing diisooctyl 1,4-cyclohexanedicarboxylate from dioctyl terephthalate on the basis of the prior art, so as to solve the problems of low conversion rate of dioctyl terephthalate and poor selectivity of diisooctyl 1,4-cyclohexanedicarboxylate in the prior art.

[0005] The method for preparing 1,4-cyclohexanedicarboxylic acid diisooctyl ester by selective hydrogenation of dioctyl terephthalate provided by the present invention comprises: in the presence of hydrogen, a dioctyl terephthalate solution is contacted with a selective hydrogenation catalyst under selective hydrogenation reaction conditions to react, and the reaction effluent is separated to obtain a 1,4-cyclohexanedicarboxylic acid diisooctyl ester product, wherein the solvent of the dioctyl terephthalate solution is isooctyl ester, and the mass concentration of the dioctyl terephthalate solution is 10% to 80%;

[0006] The selective hydrogenation catalyst comprises a carrier, an active component and an auxiliary agent, wherein the carrier is one or more selected from MCM-41, SBA-15, and MCM-48, the active component is ruthenium, and the auxiliary agent is one or more selected from cerium, lanthanum, and titanium. Based on the overall selective hydrogenation catalyst, the active component content is 0.1-10% by mass, and the auxiliary agent content is 0.5-15% by mass.

[0007] The dioctyl terephthalate (DOTP) of the present invention has the molecular formula: 24 H 38 O4, molecular weight: 390.5. The 1,4-cyclohexanedicarboxylic acid diisooctyl ester (DEHCH), its molecular formula: C 24 H 44 O4, molecular weight: 396.6.

[0008] In one embodiment of the present invention, in the selective hydrogenation catalyst, based on the whole selective hydrogenation catalyst, the content of active components is 0.2-9% by mass, and the content of auxiliary agents is 0.6-14% by mass.

[0009] In one embodiment of the present invention, in the selective hydrogenation catalyst, based on the whole selective hydrogenation catalyst, the content of active components is 0.2-5% by mass, and the content of auxiliary agents is 0.6-12% by mass.

[0010] More preferably, in the selective hydrogenation catalyst, based on the entire selective hydrogenation catalyst, the active component content is 0.2-4% by mass, and the auxiliary agent content is 0.6-10% by mass.

[0011] In one embodiment of the present invention, the selective hydrogenation reaction conditions are: reaction temperature 130-200°C, pressure 0.5-10.0 MPa, liquid hourly mass space velocity of DOTP 0.5-3.0 h -1 , gas-liquid ratio 200~900:1.

[0012] In one embodiment of the present invention, the selective hydrogenation catalyst is reduced before use, and the reduction reaction conditions are: the reduction temperature is 240-300° C., the reducing gas comprises at least hydrogen and nitrogen, the hydrogen content is 30%-99% by volume, and the gas hourly space velocity of the reducing gas is 3000-6000 mL / g cat / h.

[0013] In one embodiment of the present invention, the selective hydrogenation catalyst is prepared by the following preparation method:

[0014] (1) Carrier modification: the carrier is immersed in a solution containing an additive salt, and then dried and calcined to obtain an additive-modified carrier;

[0015] (2) loading active metals, placing the additive-modified carrier into a solution containing an active component salt for immersion to load the active component, and obtaining a selective hydrogenation catalyst after drying and calcination;

[0016] The ratio between the volume of the solution containing the auxiliary salt and the volume of water absorbed by the carrier is 1.0 to 1.5, and the ratio between the volume of the solution containing the active ingredient salt and the volume of water absorbed by the carrier is 1.0 to 1.5;

[0017] The mass concentration of the solution containing the active component salt is 0.3% to 7% based on the active component element, and the mass concentration of the solution containing the auxiliary agent salt is 2.4% to 50% based on the auxiliary agent element.

[0018] The active component salt is one or more selected from ruthenium chloride and ruthenium nitrosyl nitrate, the auxiliary salt is one or more selected from nitrate and chloride, the solvent of the solution containing the active component salt is deionized water, and the solvent of the solution containing the auxiliary salt is deionized water.

[0019] In one embodiment of the present invention, in step (1), the impregnation temperature is 20-60°C, the impregnation time is 0.1-2h, the drying temperature is 110-130°C, the drying time is 2-6h, the roasting temperature is 300-600°C, and the roasting time is 2-6h.

[0020] In one embodiment of the present invention, in step (2), the impregnation temperature is 20-60°C, the impregnation time is 0.1-2h, the drying temperature is 110-130°C, the drying time is 2-6h, the roasting temperature is 300-600°C, and the roasting time is 2-6h.

[0021] In one embodiment of the present invention, in step (1), a surfactant is added to a solution containing an auxiliary salt, and the surfactant is selected from one or more of polyvinyl pyrrolidone (PVP), hexadecyltrimethylammonium bromide (CTAB), and polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer (P123).

[0022] In one embodiment of the present invention, the amount of surfactant added is 0.1% to 1% based on the mass of deionized water in the solution containing the auxiliary salt.

[0023] The invention is characterized in that, by adopting the selective hydrogenation method provided by the invention, the conversion rate of dioctyl terephthalate is high, and the selectivity of the obtained diisooctyl 1,4-cyclohexanedicarboxylate is high. In addition, the selective hydrogenation catalyst of the invention uses metal ruthenium as the main active component, and cerium, lanthanum and titanium as auxiliary agents to modify the carrier. The preparation process of the prepared selective hydrogenation catalyst is simple, the production cost is low, and it is suitable for large-scale production. DETAILED DESCRIPTION

[0024] The following examples will further illustrate the present invention, but should not be construed as limiting the present invention.

[0025] In the embodiments and comparative examples, the calculation formulas for conversion and selectivity are as follows:

[0026]

[0027]

[0028] Where: A DOTP is the peak area of ​​the unreacted di(2-ethylhexyl)terephthalate (DOTP) component, mm 2 ; A DEHCH is the peak area of ​​the target product diisooctanol cyclohexanedicarboxylate (DEHCH), mm 2 ;∑A j is the sum of the peak areas of the by-product components, mm 2 .

[0029] In the catalyst preparation example, the carrier used is shown in Table 1.

[0030] Table 1

[0031]

[0032] The carriers used were all purchased from the catalyst factory of Nankai University. Except for the AlMCM-41 carrier containing a small amount of Al, the other carriers were all-silicon molecular sieves.

[0033] Catalyst Preparation Example 1

[0034] (1) Carrier modification

[0035] 2.56g of cerium nitrate hexahydrate was dissolved in 7.52g of deionized water, and 0.4g of CTAB was added. After stirring evenly, 10.0g of SBA-15 carrier was added. After impregnation at 55°C for 0.3h, solid-liquid separation was performed. The solid phase material was dried at 120°C for 6h and calcined at 350°C for 2h to obtain a carrier modified with the additive Ce.

[0036] (2) Impregnation of active metals

[0037] 7.2 g of deionized water was added to 2.11 g of ruthenium nitrate solution (Ru content 4.8% wt), and after stirring evenly, 10 g of the support modified by the additive Ce obtained in step (1) was added. After impregnation at 30° C. for 0.4 h, solid-liquid separation was performed. The solid phase material was dried at 120° C. for 6 h and calcined at 350° C. for 2 h to obtain a selective hydrogenation catalyst, named 1Ru7.5Ce / SBA-15. For details, please see Table 2.

[0038] Catalyst Preparation Example 2-4

[0039] The same preparation method as in Catalyst Preparation Example 1 was used, except that a different carrier was used. Please see Table 2 for details.

[0040] Catalyst Preparation Example 5

[0041] (1) Carrier modification

[0042] 2.56g of cerium nitrate hexahydrate was dissolved in 7.52g of deionized water, and 0.4g of CTAB was added. After stirring evenly, 10.0g of SBA-15 carrier was added. After impregnation at 55°C for 0.3h, solid-liquid separation was performed. The solid phase material was dried at 120°C for 6h and calcined at 350°C for 2h to obtain a carrier modified with the additive Ce.

[0043] (2) Impregnation of active metals

[0044] 1.06 g of ruthenium nitrate solution (Ru content 4.8% wt) was added with 7.2 g of deionized water. After stirring evenly, 10 g of the support modified with the auxiliary agent Ce obtained in step (1) was added. After impregnation at 30° C. for 0.4 h, solid-liquid separation was performed. The solid phase material was dried at 120° C. for 6 h and calcined at 350° C. for 2 h to obtain a selective hydrogenation catalyst named 0.5Ru7.5Ce / SBA-15. For details, please see Table 2.

[0045] Catalyst Preparation Example 6

[0046] (1) Carrier modification

[0047] 2.56g of cerium nitrate hexahydrate was dissolved in 7.52g of deionized water, and 0.4g of CTAB was added. After stirring evenly, 10.0g of SBA-15 carrier was added. After impregnation at 55°C for 0.3h, solid-liquid separation was performed. The solid phase material was dried at 120°C for 6h and calcined at 350°C for 2h to obtain a carrier modified with the additive Ce.

[0048] (2) Impregnation of active metals

[0049] 7.2 g of deionized water was added to 3.17 g of ruthenium nitrate solution (Ru content 4.8% wt), and after stirring evenly, 10 g of the support modified by the auxiliary agent Ce obtained in step (1) was added. After impregnation at 30° C. for 0.4 h, solid-liquid separation was performed. The solid phase material was dried at 120° C. for 6 h and calcined at 350° C. for 2 h to obtain a selective hydrogenation catalyst named 1.5Ru7.5Ce / SBA-15. For details, please see Table 2.

[0050] Catalyst Preparation Example 7

[0051] (1) Carrier modification

[0052] 2.22g of lanthanum nitrate hexahydrate was dissolved in 7.52g of deionized water, and 0.4g of P123 was added. After stirring evenly, 10.0g of SBA-15 carrier was added. After soaking at 50°C for 0.3h, solid-liquid separation was performed. The solid phase material was dried at 120°C for 6h and calcined at 350°C for 2h to obtain the carrier modified with the additive La.

[0053] (2) Impregnation of active metals

[0054] 7.2 g of deionized water was added to 2.11 g of ruthenium nitrosyl nitrate solution (Ru content 4.8% wt), and after stirring evenly, 10 g of the carrier modified with the auxiliary agent La obtained in step (1) was added. After impregnation at 25° C. for 0.5 h, solid-liquid separation was performed. The solid phase material was dried at 120° C. for 6 h and calcined at 350° C. for 2 h to obtain a selective hydrogenation catalyst, named 1Ru7.5La / SBA-15. For details, please see Table 2.

[0055] Catalyst Preparation Example 8

[0056] (1) Carrier modification

[0057] 3.41g titanium tetrachloride was dissolved in 8.16g deionized water, 0.4g PVP was added, and after stirring evenly, 10.0g SBA-15 carrier was added. After immersion at 30°C for 0.3h, solid-liquid separation was performed. The solid phase material was dried at 120°C for 6h and calcined at 350°C for 2h to obtain a carrier modified with additive Ti.

[0058] (2) Impregnation of active metals

[0059] 7.2 g of deionized water was added to 2.11 g of ruthenium nitrosyl nitrate solution (Ru content 4.8% wt), and after stirring evenly, 10 g of the carrier modified with the auxiliary agent Ti obtained in step (1) was added. After impregnation at 20° C. for 1 h, solid-liquid separation was performed. The solid phase material was dried at 120° C. for 6 h and calcined at 350° C. for 2 h to obtain a selective hydrogenation catalyst named 1Ru7.5Ti / SBA-15. For details, please see Table 2.

[0060] Catalyst Comparative Example 1

[0061] 2.56g of cerium nitrate hexahydrate was dissolved in 7.52g of deionized water, and 0.4g of CTAB was added. After stirring evenly, 10.0g of γ-Al2O3 carrier was added into the impregnation solution. After impregnation at 55°C for 0.3h, solid-liquid separation was carried out. The solid phase material was dried at 120°C for 6h and calcined at 350°C for 2h to obtain the support modified by the additive Ce.

[0062] 7.2 g of deionized water was added to 2.11 g of ruthenium nitrate solution (Ru content 4.8% wt). After stirring evenly, 10.0 g of γ-Al2O3 carrier modified with Ce was added. After impregnation at 30°C for 0.4 h, solid-liquid separation was performed. The solid phase material was dried at 120°C for 6 h and calcined at 350°C for 2 h to obtain a selective hydrogenation catalyst named 1Ru7.5Ce / Al2O3. For details, please see Table 2.

[0063] Catalyst Comparative Example 2

[0064] 7.2 g of deionized water was added to 2.11 g of ruthenium nitrosyl nitrate solution (Ru content 4.8% wt). After stirring evenly, 10.0 g of SBA-15 carrier was added. After impregnation at 30 ° C for 0.4 h, solid-liquid separation was performed. The solid phase material was dried at 120 ° C for 6 h and calcined at 350 ° C for 2 h to obtain a selective hydrogenation catalyst containing the active component Ru and no additives, named 1Ru / SBA-15. For details, please see Table 2.

[0065] Table 2

[0066]

[0067] Examples 1-8, Comparative Examples 1-2

[0068] 2 mL of the catalyst prepared above was placed in a fixed bed for DOTP hydrogenation experiment. Before the reaction, the catalyst was first reduced at 240° C. for 2 h in a hydrogen atmosphere.

[0069] The mass concentration of the dioctyl terephthalate solution used was 20wt% (the solvent was isooctyl alcohol). The dioctyl terephthalate solution was contacted with the selective hydrogenation catalyst obtained in the catalyst preparation example in the presence of hydrogen under selective hydrogenation reaction conditions to react. After 6 hours of reaction, the product at steady state was taken for chromatographic analysis. The calculated results after analysis are shown in Table 3.

[0070] Selective hydrogenation reaction conditions: temperature 150°C, pressure 4.0 MPa, liquid hourly mass space velocity of the reaction raw material DOTP 1.0 h -1 , gas-liquid ratio 600:1.

[0071] Table 3

[0072]

[0073] From the reaction results in Table 3, it can be seen that the carrier of the selective hydrogenation catalyst used in Comparative Example 1 is γ-alumina, and the carrier of the selective hydrogenation catalyst used in Example 1 is a mesoporous molecular sieve. The DOTP conversion rate and the selectivity of the target product DEHCH in Example 1 are significantly higher than those in Comparative Example 1. The carrier of the selective hydrogenation catalyst in Comparative Example 2 is not modified with an additive, while the selective hydrogenation catalysts of Examples 1-8 are modified with additives such as Ce, La or Ti, and their DOTP conversion rates and DEHCH selectivities are higher than those in Comparative Example 2.

[0074] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A hydrogenation method for preparing diisooctyl 1,4-cyclohexanedicarboxylate from dioctyl terephthalate, characterized in that: The dioctyl terephthalate solution is contacted with a selective hydrogenation catalyst under the condition of selective hydrogenation in the presence of hydrogen to react, and the reaction effluent is separated to obtain a diisooctyl 1,4-cyclohexanedicarboxylate product, wherein the solvent of the dioctyl terephthalate solution is isooctyl alcohol, and the mass concentration of the dioctyl terephthalate solution is 10% to 80%; The selective hydrogenation catalyst comprises a carrier, an active component and an auxiliary agent, wherein the carrier is one or more selected from MCM-41, SBA-15, and MCM-48, the active component is ruthenium, and the auxiliary agent is one or more selected from cerium, lanthanum, and titanium. Based on the overall selective hydrogenation catalyst, the active component content is 0.1-10% by mass, and the auxiliary agent content is 0.5-15% by mass.

2. The method according to claim 1, characterized in that In the selective hydrogenation catalyst, based on the whole selective hydrogenation catalyst, the content of active components is 0.2-9% by mass, and the content of auxiliary agents is 0.6-14% by mass.

3. The method according to claim 1, characterized in that In the selective hydrogenation catalyst, based on the whole selective hydrogenation catalyst, the active component content is 0.2-5% by mass, and the auxiliary agent content is 0.6-12% by mass; Preferably, in the selective hydrogenation catalyst, based on the entire selective hydrogenation catalyst, the active component content is 0.2-4% by mass, and the auxiliary agent content is 0.6-10% by mass.

4. The method according to claim 1, characterized in that: The selective hydrogenation reaction conditions are: reaction temperature 130-200°C, pressure 0.5-10.0 MPa, liquid hourly mass space velocity of DOTP 0.5-3.0 h -1 , gas-liquid ratio 200~900:

1.

5. The method according to claim 1, characterized in that The selective hydrogenation catalyst is reduced before use. The reduction reaction conditions are: the reduction temperature is 240-300°C, the reducing gas includes at least hydrogen and nitrogen, the hydrogen content is 30%-99% by volume, and the gas hourly space velocity of the reducing gas is 3000-6000 mL / g cat / h.

6. The method according to claim 1, characterized in that The selective hydrogenation catalyst is prepared by the following preparation method: (1) Carrier modification: the carrier is immersed in a solution containing an additive salt, and then dried and calcined to obtain an additive-modified carrier; (2) loading active metals, placing the additive-modified carrier into a solution containing an active component salt for immersion to load the active component, and obtaining a selective hydrogenation catalyst after drying and calcination; The ratio between the volume of the solution containing the auxiliary salt and the volume of water absorbed by the carrier is 1.0 to 1.5, and the ratio between the volume of the solution containing the active ingredient salt and the volume of water absorbed by the carrier is 1.0 to 1.5; The mass concentration of the solution containing the active component salt is 0.3% to 7% based on the active component element, and the mass concentration of the solution containing the auxiliary agent salt is 2.4% to 50% based on the auxiliary agent element. The active component salt is one or more selected from ruthenium chloride and ruthenium nitrosyl nitrate, the auxiliary salt is one or more selected from nitrate and chloride, the solvent of the solution containing the active component salt is deionized water, and the solvent of the solution containing the auxiliary salt is deionized water.

7. The method according to claim 6, characterized in that In step (1), the impregnation temperature is 20-60°C, the impregnation time is 0.1-2h, the drying temperature is 110-130°C, the drying time is 2-6h, the roasting temperature is 300-600°C, and the roasting time is 2-6h.

8. The method according to claim 6, characterized in that In step (2), the impregnation temperature is 20-60°C, the impregnation time is 0.1-2h, the drying temperature is 110-130°C, the drying time is 2-6h, the roasting temperature is 300-600°C, and the roasting time is 2-6h.

9. The method according to claim 6, characterized in that In step (1), a surfactant is added to a solution containing an auxiliary salt, wherein the surfactant is selected from one or more of polyvinyl pyrrolidone, hexadecyltrimethylammonium bromide, and a polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer.

10. The method according to claim 9, characterized in that Based on the mass of deionized water in the solution containing the auxiliary salt, the added amount of the surfactant is 0.1% to 1%.

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