阅读说明：本技术 一种环氧丙烷的制备方法 (Preparation method of propylene oxide ) 是由 黄伟新 熊伟 张振华 于 2019-11-11 设计创作，主要内容包括：本发明提供了一种环氧丙烷的制备方法,包括以下步骤：将丙烯、氧气和氩气的混合反应气通入装有Cu<Sub>2</Sub>O催化剂的反应器中,进行反应,得到环氧丙烷；所述Cu<Sub>2</Sub>O催化剂具有规整的立方体形貌；所述Cu<Sub>2</Sub>O催化剂的尺寸为20～120nm。本发明使用小尺寸的具有立方体微观形貌的Cu<Sub>2</Sub>O作为催化剂,催化直接用分子氧气作为氧化剂的丙烯环氧化反应,具有高的环氧丙烷选择性,同时催化剂制备简单,催化反应条件温和。实验结果表明,本发明中的制备方法对目标产物环氧丙烷选择性高达80％左右。(The invention provides a preparation method of propylene oxide, which comprises the following steps: introducing mixed reaction gas of propylene, oxygen and argon into the reactor filled with Cu 2 Reacting in a reactor of an O catalyst to obtain propylene oxide; the Cu 2 The O catalyst has regular cubic morphology; the Cu 2 The size of the O catalyst is 20-120 nm. The present invention uses small-sized Cu with cubic micro-morphology 2 The O is used as a catalyst to catalyze the propylene epoxidation reaction directly using molecular oxygen as an oxidant, so that the catalyst has high propylene oxide selectivity, is simple to prepare and has mild catalytic reaction conditions. Experimental results show that the selectivity of the preparation method disclosed by the invention to a target product propylene oxide is as high as about 80%.)

1. A method for preparing propylene oxide comprises the following steps:

introducing mixed reaction gas of propylene, oxygen and argon into the reactor filled with Cu₂Reacting in a reactor of an O catalyst to obtain propylene oxide;

the Cu₂The O catalyst has regular cubic morphology; the Cu₂The size of the O catalyst is 20-120 nm.

2. The method of claim 1, wherein the Cu is₂The O catalyst is prepared according to the following steps:

mixing CuSO₄Adding the solution into ultrapure water, keeping the temperature of 25-30 ℃ for 5-10 min, then adding NaOH solution, keeping the temperature of 25-30 ℃ for 5-10 min, then adding ascorbic acid water solution, reacting the obtained mixed solution at the constant temperature of 25-30 ℃ for 30-60 min to obtain Cu₂And (3) an O catalyst.

3. The method of claim 2, wherein the ultrapure water is added with sodium citrate and then with CuSO₄A solution;

the mass of the sodium citrate and the CuSO₄CuSO in solution₄The amount ratio of (0.24 to 0.28) g: (1-1.2) mmol.

4. The method of claim 2, wherein the CuSO is applied to a substrate₄The concentration of the solution is 1-2 mol/L;

the concentration of the NaOH solution is 4-5 mol/L;

the concentration of the ascorbic acid aqueous solution is 1-2 mol/L.

5. The method of claim 4, wherein the CuSO is applied to a substrate₄The dosage relation of the solution, the NaOH solution, the ascorbic acid and the ultrapure water is as follows: (1-1.5) mL: (1-1.5) mL: (0.20-0.30 g, (400-600) mL.

6. The method of claim 1, wherein the Cu is₂The ratio of the mass of the O catalyst to the flow rate of propylene is (200 to 400) mg: (2-10) mL/min.

7. The preparation method according to claim 1, wherein the molar ratio of the propylene to the oxygen to the argon is (1-5): 1: (20-25).

8. The preparation method according to claim 1, wherein the reaction time is 30 to 50 min;

the reaction temperature is 90-150 ℃.

9. The method according to claim 1, wherein the flow rate of the mixed reaction gas is 50 to 200 mL/min.

Technical Field

The invention belongs to the technical field of nano catalysis, and particularly relates to a preparation method of propylene oxide.

Background

Propylene oxide is a high value-added commodity chemical used in the manufacture of various products. The main routes to commercial propylene oxide are the chlorohydrin process and the two variants of the hydroperoxide process, which produce tert-butanol or styrene monomer as by-products. These two variants use isobutylene and ethylbenzene as reactants, respectively. These methods have substantial drawbacks. The chlorohydrin process is the oldest and most traditional process, requires expensive oxidizing agents and produces a large amount of waste salts, is seriously polluted, is not green and environment-friendly, and has low atom utilization rate. Byproduct flows suffer from plant complexity and inefficient marketing/generation. The formation of by-products is particularly problematic because their price and capacity requirements may not match those of propylene oxide, making it difficult to optimize the process.

Direct utilization of O₂The selective catalytic partial oxidation of propylene to propylene oxide is an ideal green process. Many researchers have been working on achieving high selectivity to propylene oxide in propylene epoxidation reactions. Cu-based catalysts as a relatively inexpensive material in the direct use of O₂The catalytic performance of propylene oxide to propylene oxide is very good, so that it is considered as a promising catalyst for propylene epoxidation. Since propylene oxide formed during the reaction is readily isomerized to propenol at elevated temperatures and then further oxidized to acrolein or completely burned to CO₂Resulting in a decrease in propylene oxide selectivity, Cu-based catalysts catalyze the epoxidation of propylene to propylene oxide with generally low selectivity, most not exceeding 50%, at high temperatures.

Disclosure of Invention

The invention aims to provide a preparation method of propylene oxide, which has high selectivity, simple preparation of a catalyst and mild catalytic reaction conditions.

The invention provides a preparation method of propylene oxide, which comprises the following steps:

introducing mixed reaction gas of propylene, oxygen and argon into the reactor filled with Cu₂Reacting in a reactor of an O catalyst to obtain propylene oxide;

the Cu₂The O catalyst has regular cubic morphology; the Cu₂The size of the O catalyst is 20-120 nm.

Preferably, the Cu₂The O catalyst is prepared according to the following steps:

mixing CuSO₄Adding the solution into ultrapure water, keeping the temperature of 25-30 ℃ for 5-10 min, then adding NaOH solution, keeping the temperature of 25-30 ℃ for 5-10 min, then adding ascorbic acid water solution, and reacting the obtained mixed solution at the constant temperature of 25-30 DEG CReacting for 30-60 min to obtain Cu₂And (3) an O catalyst.

Preferably, after adding the sodium citrate into the ultrapure water, adding the CuSO₄A solution;

the mass of the sodium citrate and the CuSO₄CuSO in solution₄The amount ratio of (0.24 to 0.28) g: (1-1.2) mmol.

Preferably, the CuSO₄The concentration of the solution is 1-2 mol/L;

the concentration of the NaOH solution is 4-5 mol/L;

the concentration of the ascorbic acid aqueous solution is 1-2 mol/L.

Preferably, the CuSO₄The dosage relation of the solution, the NaOH solution, the ascorbic acid and the ultrapure water is as follows: (1-1.5) mL: (1-1.5) mL: (0.20-0.30 g): (400-600) mL.

Preferably, the Cu₂The ratio of the mass of the O catalyst to the flow rate of propylene is (200 to 400) mg: (2-10) mL/min.

Preferably, the molar ratio of the propylene to the oxygen to the argon is (1-5): 1: (20-25).

Preferably, the reaction time is 30-50 min;

the reaction temperature is 90-150 ℃.

Preferably, the flow rate of the mixed reaction gas is 50-200 mL/min.

The invention provides a preparation method of propylene oxide, which comprises the following steps: introducing mixed reaction gas of propylene, oxygen and argon into the reactor filled with Cu₂Reacting in a reactor of an O catalyst to obtain propylene oxide; the Cu₂The O catalyst has regular cubic morphology; the Cu₂The size of the O catalyst is 20-120 nm. The present invention uses small-sized Cu with cubic micro-morphology₂The O is used as a catalyst to catalyze the propylene epoxidation reaction directly using molecular oxygen as an oxidant, so that the catalyst has high propylene oxide selectivity, is simple to prepare and has mild catalytic reaction conditions. Experimental results show that the selectivity of the preparation method disclosed by the invention to a target product propylene oxide is as high as about 80%.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

FIG. 1 shows cubic Cu in example 1 of the present invention₂SEM image of O nanocrystal;

FIG. 2 shows cubic Cu in example 2 of the present invention₂SEM image of O nanocrystal;

FIG. 3 shows cubic Cu in example 3 of the present invention₂SEM image of O nanocrystal;

FIG. 4 is an XRD pattern of three sizes of cubic cuprous oxide nanocrystals prepared in examples 1-3 of the present invention;

FIG. 5 shows cubic Cu in example 1 of the present invention₂A catalytic performance diagram of the O nanocrystal in a propylene selective oxidation reaction directly taking oxygen as an oxidant;

FIG. 6 shows cubic Cu in example 2 of the present invention₂A catalytic performance diagram of the O nanocrystal in a propylene selective oxidation reaction directly taking oxygen as an oxidant;

FIG. 7 shows cubic Cu in example 3 of the present invention₂A catalytic performance diagram of the O nanocrystal in a propylene selective oxidation reaction directly taking oxygen as an oxidant;

FIG. 8 shows cubic Cu in examples 1 to 3 of the present invention₂A comparison graph of catalytic performance of O nanocrystals in propylene selective oxidation reactions directly using oxygen as the oxidant.

Detailed Description

The invention provides a preparation method of propylene oxide, which comprises the following steps:

introducing mixed reaction gas of propylene, oxygen and argon into the reactor filled with Cu₂Reacting in a reactor of an O catalyst to obtain propylene oxide;

the Cu₂The O catalyst has regular cubic morphology; the Cu₂The size of the O catalyst is 20-120 nm.

In the present invention, Cu is preferable₂And (3) filling the O catalyst into a reactor, detecting the reaction temperature by a thermocouple arranged in the middle of the catalyst bed, introducing mixed reaction gas of propylene, oxygen and argon into the reactor, and reacting to obtain the propylene oxide.

In the invention, the propylene, the oxygen and the argon are all commercial products, and the molar ratio of the propylene to the oxygen to the argon is (1-5): 1: (20 to 25), specifically, in the embodiment of the present invention, the ratio of 2:1: 22; the flow rate of the mixed reaction gas is preferably 50-200 mL/min, and more preferably 100-150 mL/min. The Cu₂The ratio of the mass of the O catalyst to the flow rate of propylene is preferably (200 to 400) mg: (2-10) mL/min, more preferably 200 mg: 4 mL/min.

The Cu₂The O catalyst has regular cubic morphology, and the Cu₂The size of the O catalyst is 20-120 nm, and more preferably 30-100 nm; in the present invention, the Cu₂The dimensions of the O catalyst refer to the side length of the cube.

In the present invention, Cu having a size of 20 to 50nm₂The O catalyst is preferably prepared according to the following steps:

mixing CuSO₄Adding the solution into ultrapure water, keeping the temperature of 25-30 ℃ for 5-10 min, then adding NaOH solution, keeping the temperature of 25-30 ℃ for 5-10 min, then adding ascorbic acid water solution, reacting the obtained mixed solution at 25-30 ℃ for 30-60 min to obtain Cu with the size of 20-50 nm₂And (3) an O catalyst.

In the present invention, the CuSO₄The dosage relation of the solution, the NaOH solution, the ascorbic acid and the ultrapure water is as follows: (1-1.5) mL: (1-1.5) mL: (0.20-0.30) g: (400-600) mL, specifically, in the embodiment of the present invention, the volume may be 1 mL: 1mL of: 0.21 g: 400 mL; the CuSO₄The concentration of the solution is preferably 1-2 mol/L, and more preferably 1.2-1.8 mol/L; the concentration of the NaOH solution is preferably 4-5 mol/L, and more preferably 4.5-4.8 mol/L; the concentration of the ascorbic acid is preferably1 to 2mol/L, more preferably 1.2 to 1.8 mol/L.

The Cu prepared by the preparation method is 20-50 nm in size₂O catalyst, Cu with the size of 80-120 nm₂Adding sodium citrate into ultrapure water, and then adding CuSO into the ultrapure water₄Solution, subsequent preparation steps and preparation of Cu with size of 20-50 nm as described above₂The O catalyst step is the same. And will not be described in detail herein.

In the invention, the mass of the sodium citrate is equal to that of CuSO₄CuSO in solution₄The amount ratio of (2) is preferably (0.24 to 0.28) g: (1-1.2) mmol, specifically, 0.2647 g: 1.2 mmol.

In the invention, the reaction time is preferably 30-50 min, more preferably 35-45 min, and most preferably 40 min; the reaction temperature is preferably 90-130 ℃, more preferably 100-120 ℃, and specifically, the reaction temperature can be 90 ℃, 110 ℃, 130 ℃ or 150 ℃.

The invention provides a preparation method of propylene oxide, which comprises the following steps: introducing mixed reaction gas of propylene, oxygen and argon into the reactor filled with Cu₂Reacting in a reactor of an O catalyst to obtain propylene oxide; the Cu₂The O catalyst has regular cubic morphology; the Cu₂The size of the O catalyst is 20-120 nm. The present invention uses small-sized Cu with cubic micro-morphology₂The O is used as a catalyst to catalyze the propylene epoxidation reaction directly using molecular oxygen as an oxidant, so that the catalyst has high propylene oxide selectivity, is simple to prepare and has mild catalytic reaction conditions. Experimental results show that the selectivity of the preparation method disclosed by the invention to a target product propylene oxide is as high as about 80%.

In order to further illustrate the present invention, the following examples are provided to describe the preparation method of propylene oxide of the present invention in detail, but should not be construed as limiting the scope of the present invention.