Process for stereoselective hydrogenation of phthalic acid esters
By adding Pt/TiO2 catalyst to the phthalate and controlling the reaction conditions, efficient stereoselective hydrogenation is achieved, and the problem of insufficient optical purity and yield of the product in the prior art is solved, and the catalyst has good cycling performance.
Patent Information
- Application Number
- CN202411787120.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-12-08
- Filing Date
- 2024-12-06
- Publication Date
- 2025-06-10
AI Technical Summary
The prior art is difficult to achieve stereoselective hydrogenation of phthalate, resulting in insufficient optical purity and yield of the product.
The reaction mixture is reacted and converted to a specific compound by adding a Pt/TiO2 catalyst to the pre-loaded phthalate and feeding hydrogen under specific conditions. The method includes controlling the amount of catalyst added, the feed pressure of hydrogen gas, and the reaction temperature.
A yield of 96% and an optical purity of 99:1 were achieved, significantly improving the efficiency of stereoselective hydrogenation. The catalyst can be reused, and the cycle times exceeds four times and remains efficient.
Smart Images
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Abstract
Description
Field of the Invention
[0001] The present invention relates to a method for the stereoselective hydrogenation of phthalates, a hydrogenation catalyst, and a hydrogenated phthalate. Summary of the Invention
[0002] An object of the present invention is to provide a method for the stereoselective hydrogenation of phthalates.
[0003] This object is achieved by the method according to claim 1.
[0004] A method, comprising the following method steps:
[0005] a) Preloading a phthalate according to formula (I):
[0006]
[0007] wherein n and m are each independently integers from 0 to 12;
[0008] b) Adding Pt / TiO 2 ;
[0009] c) Feeding in H 2 ;
[0010] d) Reacting the reaction mixture from a) to c), wherein the phthalate is converted into a compound according to formula (II):
[0011]
[0012] In one variant of the method, n and m are the same number.
[0013] In one variant of the method, n and m are numbers from 4 to 8.
[0014] In one variant of the method, the phthalate has structure (1):
[0015]
[0016] In one variant of the method, the addition amount of Pt / TiO 2 is 0.1 mol% Pt to 5 mol% Pt (based on the phthalate).
[0017] In one variant of the method, the feeding in of H 2 is carried out under a pressure of 0.5 MPa (5 bar) to 10 MPa (100 bar).
[0018] In one variant of the method, the reaction of the reaction mixture is carried out at a temperature of 20 °C to 120 °C.
[0019] In a variant of the method, the reaction of the reaction mixture is carried out at a temperature of 20 °C to 100 °C.
[0020] In a variant of the method, the method comprises an additional method step c'):
[0021] c') adding a solvent.
[0022] In a variant of the method, the solvent is cyclohexane.
[0023] In addition to the said method, the resulting product is also claimed.
[0024] Compound having structure (1):
[0025]
[0026] Furthermore, the use of the catalyst used in the corresponding reaction is also claimed.
[0027] Pt / TiO 2 Use of the catalyst for the stereoselective hydrogenation of aromatic compounds.
[0028] In one embodiment, the aromatic compound is a phthalate. Detailed Description of the Invention
[0029] The present invention will be described in more detail below with reference to the examples.
[0030] Experimental description
[0031] Preparation of the Catalyst
[0032] A supported Pt catalyst with a Pt loading of 6 wt% was synthesized according to the wet impregnation method. For a typical catalyst preparation (0.5 g), an aqueous solution of hexachloroplatinic acid (7.5 mg Pt ml -1 , AlfaAesar) was diluted with deionized water to 16 ml and heated to 60 °C in an oil bath with vigorous stirring (800 rpm) for 15 minutes, and then TiO 2 support (P25, Sigma-Aldrich) was added. The temperature was maintained at 60 °C for 16 hours. After cooling, the water was removed by rotary evaporation. Then the formed material was placed in a furnace at 110 °C overnight. The sample was thoroughly ground and then calcined at 450 °C at a heating rate of 10 °C min -1 for 4 hours. Finally, the sample was placed in a flow-through tubular furnace and reduced at 250 °C at a heating rate of 5 °C min 2 under a constant flow of 5% H -1 for 1 h.
[0033] Stereoselective Hydrogenation of Di-n-octyl Phthalate
[0034] a) By 0.5 mol% Pt / TiO 2 Reaction
[0035]
[0036] 0.5 mol% of Pt / TiO 2 (6 wt%) was added to a 4 ml screw-cap reaction vessel equipped with a magnetic stirrer and a septum cap, along with the substrate (195.3 mg, 0.5 mmol) and cyclohexane (2 ml). Then a needle was inserted through the septum, allowing H 2 to permeate into the vial. The vial was inserted into an alloy plate and placed in a 300 ml steel Parr autoclave. The autoclave was purged three times with H 2 at 10 bar and finally pressurized to 10 bar. It was then placed in an aluminum block and maintained at 25 °C for 16 h. Finally, the sample was removed from the autoclave by adding ethyl acetate to the crude mixture, followed by filtration to separate the solid catalyst using a C salt pad. The product was separated using silica gel column chromatography (ethyl acetate / pentane = 1 / 4).
[0037] Yield: 96%.
[0038] Optical purity: 99:1
[0039] b) By 10 g Pt / TiO 2 Reaction
[0040] 10 g of Pt / TiO 2 catalyst (6 wt% Pt) and 250 ml of the substrate were added to a 450 ml stainless steel autoclave from Parr Instruments. The autoclave was purged three times with 5 bar of hydrogen. 40 bar of hydrogen was introduced into the autoclave and the reaction was carried out under mechanical stirring. The reaction temperature was 80 °C and the H 2 pressure was 40 bar. The reaction time was 24 h. After the gas consumption ended, the reactor was cooled to room temperature and the pressure was released.
[0041] After the reaction, the solid catalyst and the product were separated by filtration.
[0042] Yield: >98%.
[0043] c) Recycling of the catalyst
[0044] The catalyst was washed with cyclohexane and then dried in an oven at 80 °C for 2 hours. Subsequently, the catalyst was collected and thoroughly crushed, and then placed in a vacuum device overnight to completely remove the adsorbed substances. The recycled catalyst can be directly used for the next round without further regeneration. Four cycles were carried out. More than 98% of the desired product was obtained in each round.
[0045] The experimental results show that the object is achieved by the method of the present invention.
Claims
1. A method comprising the following steps: a) Pre-loading with a phthalate ester according to formula (I): wherein n and m are each independently an integer from 0 to 12; b) Adding Pt / TiO2; c) supplying H2; d) reacting the reaction mixture from a) to c), wherein the phthalic acid ester is converted into a compound according to formula (II):
2. The method according to claim 1, Where n and m are the same number.
3. The method according to any one of claims 1 or 2, Wherein n and m are numbers from 4 to 8.
4. The method according to any one of claims 1 to 3, The phthalate ester has the structure (1):
5. The method according to any one of claims 1 to 4, The added amount of Pt / TiO2 is 0.1 mol % Pt to 5 mol % Pt (based on the phthalate).
6. The method according to any one of claims 1 to 5, The H2 is fed in at a pressure of 0.5 MPa (5 bar) to 10 MPa (100 bar).
7. The method according to any one of claims 1 to 6, The reaction of the reaction mixture is carried out at a temperature of 20°C to 120°C.
8. The method according to any one of claims 1 to 7, It comprises the additional method step c'): c') Adding solvent.
9. The method according to claim 8, The solvent is cyclohexane.
10. A compound having the structure (1):
11. Use of Pt / TiO2 catalyst for catalyzing stereoselective hydrogenation of aromatic compounds.
12. The use according to claim 11, The aromatic compound is a phthalate.