High-pressure kettle type propiolactone preparation and synthesis process

Abstract

The invention belongs to the field of propiolactone preparation, and particularly relates to a method for preparing propiolactone in an autoclave mode and synthesizing propiolactone by using a semi-porphyrin-like chromium-cobalt bimetallic complex as a catalyst. In the preparation process, the propiolactone (BPL) is synthesized by increasing the pressure of the reactant carbon monoxide so as to reduce the dosage of the catalyst, so that the technical bottleneck is broken through, and remarkable technical advantages are achieved.

Description

Technical Field

[0001] The invention belongs to the field of propiolactone synthesis, and specifically relates to a method for synthesizing propiolactone by using a semiporphyrin-like ligand, a metal chromium cation of a Lewis acid and an anion complex of cobalt tetracarbonyl as a catalyst through an autoclave. Background Art

[0002] BPL is an important raw material in pharmaceutical chemical industry, with annual global consumption of millions of tons and sales exceeding 10 billion US dollars. At present, the new catalytic technology developed by Novomer and Praxair is more advantageous in terms of synthesis technology. In this technology, a continuous process technology is adopted, CO2 is used as the starting material to obtain CO through the catalytic reduction system developed by Praxair, and then CO participates in the insertion reaction of ethylene oxide to generate the target product. The present invention mainly refers to Organic Letters (2006), 8 (17), 3709-3712. The reaction under normal pressure CO was reported by Professor Coates' research group in 2006. The references did not disclose the preparation of unsubstituted BPL by this route. The inventor found through research that the unsubstituted BPL prepared by this preparation method is prone to polymerization, and the catalyst content in the references is as high as 2 mol%.

[0003] Moreover, in the prior art, the mature industrial method for preparing propiolactone is a continuous high-pressure reaction technology. This high-pressure technology has very high requirements for continuous equipment and is currently not available in China, resulting in a blank state for the industrialized production of propiolactone. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a more efficient process for preparing propiolactone.

[0005] In the first aspect, ethylene oxide (EO) is reacted with carbon monoxide, wherein the catalyst is a semiporphyrin-like (also known as a Schiff base ligand) as a ligand, a complex of metal chromium as a Lewis acid cation and cobalt tetracarbonyl as an anion, and is added to an autoclave to react and prepare propiolactone:

[0006]

[0007] Wherein, the L group of the catalyst is tetrahydrofuran (THF), R 1-4 The group is alkyl, aryl or halogen.

[0008] Furthermore, the catalyst content is 1 mol%.

[0009] Among them, the pressure range of CO is 2~6Mpa.

[0010] More preferably, it is 2.5Mpa.

[0011] Wherein, the reaction solvent is dimethyl ether (DME).

[0012] Wherein, the reaction time is 72 hours and the reaction temperature is 60°C.

[0013] Autoclave refers to the equipment used in industry to carry out chemical reactions under high pressure, also called pressure kettle. The lid of the autoclave is equipped with a pressure gauge, bursting membrane safety device, vapor-liquid phase valve, temperature sensor, etc., which are convenient for understanding the reaction situation in the autoclave at any time, adjusting the medium ratio in the autoclave, and ensuring safe operation.

[0014] The CO pressure control of the present invention is implemented by an autoclave.

[0015] The catalyst can also be a complex of a semiporphyrin-like ligand (also known as a Schiff base ligand), a metal chromium cation of a Lewis acid and a corresponding anion. Preferably, the catalyst is a complex of a semiporphyrin-like ligand (also known as a Schiff base ligand) as a ligand, metal chromium as a Lewis acid cation and cobalt tetracarbonyl as an anion.

[0016] In another aspect, the present invention provides a process for synthesizing a catalyst:

[0017] Compound S-1 and compound S-2 react to prepare compound S-3,

[0018]

[0019] Wherein, the reaction solvent is methanol.

[0020] Wherein, the reaction time is 4 hours.

[0021] Compound S-3 is used to prepare compound S-4.

[0022]

[0023] Wherein, the reaction reagents are CrCl2 and oxygen,

[0024] Wherein, the reaction solvent is THF.

[0025] Wherein, the reaction time is 24 hours and the reaction temperature is room temperature.

[0026] Compound S-4 is used to prepare compound catalyst 1.

[0027]

[0028] Wherein, the reaction reagent is NaCo(CO)4.

[0029] Wherein, the reaction solvent is THF.

[0030] Wherein, the reaction temperature is room temperature.

[0031] The invention provides an efficient route for preparing propiolactone, and can produce a propiolactone product without a substituent. The method uses a highly efficient semiporphyrin-like (also called Schiff base ligand) as a ligand, metal chromium as a Lewis acid cation and cobalt tetracarbonyl as an anion complex catalyst to synthesize in an autoclave, appropriately increases the pressure of CO to reduce the amount of catalyst used to synthesize propiolactone (BPL), breaks through the technical bottleneck, and achieves significant technical advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is the product propiolactone in Example 1 of the present invention 1 H-NMR spectrum.

[0033] Figure 2 This is the infrared detection image of the product cat.-1 in Example 4 of the present invention. DETAILED DESCRIPTION

[0034] In order to further understand the present invention, the present invention is described in detail below in conjunction with the embodiments. It should be understood that these embodiments are only for further describing the features of the present invention in detail, and are not intended to limit the scope of the present invention or the scope of the claims of the present invention.

[0035] Embodiment 1:

[0036]

[0037] Under nitrogen protection, at 25°C (room temperature), cat.-1 (2.7 g, 3 mmol) was added to a 500 mL round-bottom bottle, and 20 mL of ultra-dry DME was added for standby use; the 3 L reactor was first quickly replaced with CO, and then EO (100 mL, 300 mmol, 3M / THF) and the DME solution of cat.-1 were added thereto, pressurized to 2.5.0 MPa, and reacted at 60°C for 72 h; the reaction was restored to 25°C (room temperature), vented, and the reactor was opened. The yield monitored by gas chromatography was 92%; the reaction solution was subjected to vacuum distillation to obtain pure propiolactone (note that the vacuum distillation temperature should not exceed 60 degrees Celsius, otherwise propiolactone is prone to polymerization to form polymers). 1 H-NMR (400MHz, CDCl3): δ4.27(t,J=6.0Hz,2H), 3.53(t,J=6.0Hz,2H), see Figure 1 .

[0038] Embodiment 2:

[0039]

[0040] At 25°C (room temperature), under N2 protection, S-1 (43.2 g, 400.0 mmol) and S-4 (200.4 g, 856.0 mmol) were added to a 2L three-necked round-bottom flask, and 1000 mL of barreled methanol was added. The system was then refluxed at 80°C overnight, and a yellow solid gradually precipitated from the clear and transparent system; the system was then restored to 25°C (room temperature), the suspension was filtered, and the filtrate was fully washed twice with ethanol to obtain a yellow solid, which was transferred to a 1L single-necked round-bottom flask and drained to obtain 210 g of yellow solid S-3 crude product with a yield of 97%. No purification was required for the next step of reaction;

[0041] Embodiment 3:

[0042]

[0043] At 25°C (room temperature), under N2 protection, S-3 (43.2 g, 100.0 mmol) and CrCl2 (13.5 g, 110.0 mmol) were added to a 2L three-necked round-bottom flask, and 1000 mL of ultra-dry THF was added, and the reaction was stirred for 6 h; then the stopper was opened and the reaction was left open overnight; at 25°C (room temperature), 200 ml of ether was added to the reaction system for dilution, and then the reaction system was washed three times with a saturated ammonium chloride solution and then washed three times with a saturated sodium chloride solution, the organic phase was collected, and anhydrous sodium sulfate was added to dry the mixture. The crude purple-black solid S-6 was placed in an 80°C oil bath, acetonitrile was added dropwise, and after complete dissolution, the system was taken out of the oil bath and cooled to 25°C (room temperature), and then placed in a refrigerator at -20°C overnight; the system was restored to room temperature, and finely crushed crystalline S-6 was found to be precipitated, which was filtered and the filter cake was washed three times with n-hexane. The obtained purple-black solid was transferred to a 500mL single-mouth bottle and dried to obtain 43.6g of pure purple-black solid product S-4 with a yield of 70%, and the next step of reaction was carried out.

[0044] Embodiment 4:

[0045]

[0046] In a glove box, at 25°C (room temperature), pure S-4 (20.0 g, 32 mmol) and a THF solution (about 150 mL) of NaCo(CO)4 (about 32 mmol) were added to a 1 L round-bottom bottle in sequence, followed by the addition of 400 mL of THF and stirring for 36 h; at 25°C (room temperature), 350 mL of the filtrate was removed in the glove box (a cold trap was connected to condense the THF to avoid damaging the pump); 600 mL of n-hexane was then added thereto for recrystallization at 25°C (room temperature), and the recrystallization was allowed to stand for 36 h at 25°C (room temperature); at 25°C (room temperature), in a glove box, the recrystallization system was filtered, the filter cake was washed three times with n-hexane and transferred to a 250 mL eggplant-shaped bottle, and then the solvent was drained to obtain 20.8 g of a purple-black solid product cat.-1 (23.0 mmol), with a total yield of 72%, and infrared detection showed Figure 2 .

[0047] Embodiment 5:

[0048]

[0049] At 25°C (room temperature), in a glove box, Co2(CO)8 (2.05 g, 6 mmol) and NaOH (1.92 g, 48 mmol) were added to a 100 mL three-necked round-bottom flask, and 60 mL of THF was added and stirred overnight until the solution turned into a rich purple (the system was a suspension); the suspension was then filtered to obtain a light yellow, clear and transparent NaCo(CO)4 THF solution, which was carried out in the next step without purification.

Claims

1. A method for preparing high-pressure autoclave propiolactone, comprising reacting ethylene oxide (EO) with carbon monoxide in the presence of a catalyst to obtain propiolactone. in, The catalyst is a complex of a semiporphyrin-like ligand, a metal chromium cation of a Lewis acid and a corresponding anion.

2. The preparation method according to claim 1, characterized in that: The catalyst is a semiporphyrin-like ligand, a metal chromium cation of a Lewis acid and an anion complex of tetracarbonyl cobalt.

3. A method for preparing high-pressure autoclave propiolactone, comprising reacting ethylene oxide (EO) with carbon monoxide in the presence of a catalyst to obtain propiolactone. in, The L group of the catalyst is tetrahydrofuran (THF), R 1-4 The group is alkyl, aryl or halogen.

4. The preparation method according to claim 1, 2 or 3, characterized in that: The pressure range of CO is 2~6Mpa.

5. The preparation method according to claim 1, 2 or 3, characterized in that: The catalyst content was 1 mol%.

6. The preparation method according to claim 1, 2 or 3, characterized in that: The reaction solvent is dimethyl ether (DME).

7. The preparation method according to claim 1, 2 or 3, characterized in that: The reaction time is 72 hours.

8. The preparation method according to claim 1, 2 or 3, characterized in that: The reaction temperature is 60°C.

9. The preparation method according to claim 4, characterized in that: The CO pressure was controlled by an autoclave.

10. The preparation method according to claim 1, 2 or 3, characterized in that: The preparation method of the catalyst comprises the steps of: Compound S-1 and compound S-2 react with methanol to prepare compound S-3, Compound S-3 reacts with CrCl2 and oxygen to prepare compound S-4, Compound S-4 and NaCo(CO)4 were used to prepare compound catalyst 1.

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