A process for the preparation of propylene oxide and co-production of carboxylic acid by propene epoxidation

Abstract

The application discloses a method for preparing 1,2-epoxypropane from propylene, which comprises the following steps: adding ester solvent, catalyst and cocatalyst into propylene, and then introducing air with a pressure of 0.1-2 MPa, and reacting at 25-150 DEG C for 1-24 h to obtain epoxypropane and by-product carboxylic acid compound corresponding to the structure of the ester solvent; the technical scheme provided by the application has simple reaction conditions and is easy to realize, solves the problems of serious three-waste pollution in the traditional method for preparing 1,2-epoxypropane, and effectively improves the selectivity of the method for preparing 1,2-epoxypropane by using air as an oxidant; the by-product carboxylic acid product can be recycled, combined with olefins to return to the ester compound, and the raw material is fully utilized.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of industrial catalysis and petrochemical industry, and more particularly, to a method for preparing 1,2-epoxypropane from propylene. BACKGROUND

[0002] The epoxidation reaction of olefins is an important chemical reaction, especially the reaction for preparing 1,2-epoxypropane from propylene, and the product 1,2-epoxypropane is widely used in the fields of synthesis of petrochemical products, synthesis of pharmaceutical intermediates, etc. Its production process has undergone changes from chlorohydrination method, co-oxidation method and HPPO method (i.e. hydrogen peroxide oxidation method), and is constantly developing towards green production and clean production. The chlorohydrination method gradually withdraws from the production field due to environmental pollution, equipment corrosion and other problems. The use of co-oxidation method overcomes the defects of chlorohydrination method, but it consumes a large amount of co-oxidation raw materials, and the amount of co-products is large, so a complex process flow must be adopted, resulting in high energy consumption. The HPPO method has advantages in various aspects, but its safety problems and economic cost problems are the fundamental reasons hindering its further development.

[0003] In order to solve the above problems, a more green and optimized propylene epoxidation process is proposed by directly using oxygen in air, Chinese invention patent CN111495422A discloses a method and catalyst for preparing epoxypropane and acetic acid from ethane and propylene co-oxidation, the patent uses Ti-MCM-41 molecular sieve with multiple metals such as cerium, vanadium, molybdenum and niobium as catalyst, which effectively improves the selectivity of preparing epoxypropane from ethane and propylene co-oxidation, and fundamentally solves the problems of three wastes pollution, high cost, etc. of traditional method. Chinese invention patent CN104650008A discloses a process for preparing epoxypropane by directly oxidizing propylene with oxygen and hydrogen, which is energy-saving and environmentally friendly, can significantly improve the purity and yield of epoxypropane, and reduce the loss of epoxypropane. The above process uses dangerous compounds such as co-reducing agent ethane and hydrogen, which brings more safety uncertainty.

[0004] Therefore, it is of great application prospect to develop a high-efficiency conversion process which uses propylene as raw material, oxygen as oxidant, has a simple system, is easy to realize, does not introduce dangerous gas, and has high conversion rate. SUMMARY

[0005] In view of the above shortcomings, the purpose of the present application is to provide a method for preparing epoxypropane and carboxylic acid by propylene epoxidation, which uses propylene as raw material, oxygen as oxidant, has a simple system, is easy to realize, does not introduce dangerous gas, and has high conversion rate.

[0006] To this end, the technical solution provided by the present application is as follows:

[0007] A method for preparing propylene oxide and coproducing carboxylic acid by propylene epoxidation, which comprises adding ester solvent, catalyst and cocatalyst, and introducing air at 0.1-2 MPa, and reacting at 25-150℃ for 1-24 h to prepare propylene oxide and coproduce carboxylic acid compound corresponding to the structure of the ester solvent;

[0008] The catalyst is one or more of ferric chloride hexahydrate, ferrous chloride tetrahydrate, copper chloride dihydrate, manganese chloride tetrahydrate, bismuth chloride, nickel chloride hexahydrate, chlororuthenium triphenylphosphine, water and ruthenium chloride, cobalt chloride hexahydrate and metal halide;

[0009] The molar ratio of propylene, oxygen and ester compound is 1:(0.1-5):(5-50);

[0010] The molar ratio of propylene, catalyst and cocatalyst is 1:0.0001-0.01:0.001-0.1.

[0011] Further, in the above method for preparing propylene oxide and coproducing carboxylic acid by propylene epoxidation, the cocatalyst is one or more of 4,4'-di-tert-butyl-2,2'-bipyridine, 1,3-bis(2,6-diisopropylphenyl)imidazolium chloride, tetramethylethylenediamine, imidazole, 2-methylimidazole, 5,6-dimethylphenanthroline and ethylenediaminetetraacetic acid.

[0012] Further, in the above method for preparing propylene oxide and coproducing carboxylic acid by propylene epoxidation, the ester solvent is one or more of ethyl acetate, methyl acetate, ethyl formate, isopropyl acetate, butyl acetate, sec-butyl acetate, hexyl acetate, ethyl tert-pentanoate, ethyl benzoate, dimethyl carbonate and diethyl carbonate.

[0013] Further, in the above method for preparing propylene oxide and coproducing carboxylic acid by propylene epoxidation, the molar ratio of propylene, oxygen and ester compound is 1:(1-2):(10-25).

[0014] Further, in the above method for preparing propylene oxide and coproducing carboxylic acid by propylene epoxidation, the molar ratio of propylene, catalyst and cocatalyst is 1:0.0016:0.0125.

[0015] Further, in the above method for preparing propylene oxide and coproducing carboxylic acid by propylene epoxidation, the air is introduced at 0.5-2 MPa.

[0016] Further, in the above method for preparing propylene oxide and coproducing carboxylic acid by propylene epoxidation, the reaction time is 8-12 h.

[0017] Further, the above-mentioned method for preparing propylene oxide and carboxylic acid in propene epoxidation, the reaction temperature is 100-150℃.

[0018] Compared with the prior art, the present application has the following beneficial effects:

[0019] The present application uses propylene and ester compounds as raw materials, air as oxygen source, and does not need to add additional co-oxidation substrates. In a low-load catalytic system, high selective conversion of 1,2-epoxypropane can be realized by directly activating ester solvents, and carboxylic acid is co-produced. The co-produced carboxylic acid can be re-obtained by esterification reaction, Michael addition reaction, etc. No hydrogen, sodium borohydride, lithium tetrahydroaluminate, etc. are needed for reduction. The propylene epoxidation reaction realized by the method has a green raw material, good safety, simple operation, good selective conversion effect on propylene, and good industrial application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 The gas chromatography detection chart provided for Example 1 of the present application. DETAILED DESCRIPTION

[0021] The present application will be further described below in conjunction with examples, but the present application is not limited by these examples.

[0022] Example 1

[0023] In a 100mL stainless steel autoclave with a polytetrafluoroethylene liner, 20mL of ethyl acetate, 0.0038g (0.016mmol) of cobalt chloride hexahydrate, and 0.0292g (0.1mmol) of ethylenediaminetetraacetic acid were added, the autoclave was sealed, and then 0.33g (8mmol) of propylene was introduced by weighing. Then, 0.95g (32mmol) of air was introduced into the reaction system, and the reaction was carried out at 130℃ and a rotation speed of 400rpm for 12h. After cooling and pressure relief, 2mL of the reaction liquid was taken into a headspace bottle, and quantification was performed by gas chromatography, as shown in Figure 1 , the conversion rate of propylene was 31%, the selectivity of 1,2-epoxypropane was 90%, and the yield of acetic acid was 35%.

[0024] Example 2

[0025] In a 100 mL stainless steel autoclave with a polytetrafluoroethylene liner, sec-butyl acetate 20 mL, cobalt chloride hexahydrate 0.0038 g (0.016 mmol), ethylenediaminetetraacetic acid 0.0292 g (0.1 mmol) were added, the autoclave was sealed, then propylene 0.33 g (8 mmol) was introduced, the mass of propylene was weighed. After that, air 0.95 g (32 mmol) was introduced into the reaction system, the reaction was carried out at 130 °C, 400 rpm for 12 h, cooling, pressure relief, 2 mL of the reaction solution was taken into the headspace bottle, and quantified by gas chromatography, the conversion of propylene was 10%, the selectivity of 1,2-propylene oxide was 70%, and the yield of acetic acid was 12%.

[0026] Example 3

[0027] In a 100 mL stainless steel autoclave with a polytetrafluoroethylene liner, sec-butyl acetate 20 mL, cobalt chloride hexahydrate 0.0038 g (0.016 mmol), ethylenediaminetetraacetic acid 0.0292 g (0.1 mmol) were added, the autoclave was sealed, then propylene 0.33 g (8 mmol) was introduced, the mass of propylene was weighed. After that, air 0.95 g (32 mmol) was introduced into the reaction system, the reaction was carried out at 130 °C, 400 rpm for 12 h, cooling, pressure relief, 2 mL of the reaction solution was taken into the headspace bottle, and quantified by gas chromatography, the conversion of propylene was 10%, the selectivity of 1,2-propylene oxide was 70%, and the yield of acetic acid was 12%.

[0028] Example 4

[0029] In a 100 mL stainless steel autoclave with a polytetrafluoroethylene liner, sec-butyl acetate 20 mL, cobalt chloride hexahydrate 0.0038 g (0.016 mmol), ethylenediaminetetraacetic acid 0.0292 g (0.1 mmol) were added, the autoclave was sealed, then propylene 0.33 g (8 mmol) was introduced, the mass of propylene was weighed. After that, air 0.95 g (32 mmol) was introduced into the reaction system, the reaction was carried out at 130 °C, 400 rpm for 12 h, cooling, pressure relief, 2 mL of the reaction solution was taken into the headspace bottle, and quantified by gas chromatography, the conversion of propylene was 10%, the selectivity of 1,2-propylene oxide was 70%, and the yield of acetic acid was 12%.

[0030] Example 5

[0031] In a 100 mL stainless steel autoclave with a polytetrafluoroethylene liner, isobutyl isobutyrate 20 mL, cobalt chloride hexahydrate 0.0038 g (0.016 mmol), ethylenediaminetetraacetic acid 0.0292 g (0.1 mmol) were added, the autoclave was sealed, then propylene 0.33 g (8 mmol) was introduced, the mass of propylene was weighed. After that, air 0.95 g (32 mmol) was introduced into the reaction system, the reaction was carried out at 130 °C, 400 rpm for 12 h, cooled, pressure relief, 2 mL of the reaction liquid was taken into the headspace bottle, and the conversion rate of propylene was 38%, the selectivity of 1,2-propylene oxide was 80%, and the yield of isobutyric acid was 35% by gas chromatography quantification.

[0032] Example 6

[0033] In a 100 mL stainless steel autoclave with a polytetrafluoroethylene liner, isobutyl isobutyrate 20 mL, cobalt chloride hexahydrate 0.0038 g (0.016 mmol), ethylenediaminetetraacetic acid 0.0292 g (0.1 mmol) were added, the autoclave was sealed, then propylene 0.33 g (8 mmol) was introduced, the mass of propylene was weighed. After that, air 0.95 g (32 mmol) was introduced into the reaction system, the reaction was carried out at 130 °C, 400 rpm for 12 h, cooled, pressure relief, 2 mL of the reaction liquid was taken into the headspace bottle, and the conversion rate of propylene was 38%, the selectivity of 1,2-propylene oxide was 80%, and the yield of isobutyric acid was 35% by gas chromatography quantification.

[0034] Example 7

[0035] In a 100 mL stainless steel autoclave with a polytetrafluoroethylene liner, isobutyl isobutyrate 20 mL, cobalt chloride hexahydrate 0.0038 g (0.016 mmol), ethylenediaminetetraacetic acid 0.0292 g (0.1 mmol) were added, the autoclave was sealed, then propylene 0.33 g (8 mmol) was introduced, the mass of propylene was weighed. After that, air 0.95 g (32 mmol) was introduced into the reaction system, the reaction was carried out at 130 °C, 400 rpm for 12 h, cooled, pressure relief, 2 mL of the reaction liquid was taken into the headspace bottle, and the conversion rate of propylene was 38%, the selectivity of 1,2-propylene oxide was 80%, and the yield of isobutyric acid was 35% by gas chromatography quantification.

[0036] Example 8

[0037] In a 100 mL stainless steel autoclave with a polytetrafluoroethylene liner, butyl butyrate 20 mL, cobalt chloride hexahydrate 0.0038 g (0.016 mmol), ethylenediaminetetraacetic acid 0.0292 g (0.1 mmol) were added, the autoclave was sealed, then propylene 0.33 g (8 mmol) was introduced by weighing. After that, air 0.95 g (32 mmol) was introduced into the reaction system, the reaction was carried out at 140 °C, 400 rpm for 12 h, cooled, pressure relief, 2 mL of the reaction liquid was taken into the headspace bottle, and the conversion of propylene was 35%, the selectivity of 1,2- propylene oxide was 89%, and the yield of n-butyric acid was 38% by gas chromatography quantification.

[0038] Example 9

[0039] In a 100 mL stainless steel autoclave with a polytetrafluoroethylene liner, butyl butyrate 20 mL, cobalt chloride hexahydrate 0.0038 g (0.016 mmol), ethylenediaminetetraacetic acid 0.0292 g (0.1 mmol) were added, the autoclave was sealed, then propylene 0.33 g (8 mmol) was introduced by weighing. After that, air 0.95 g (32 mmol) was introduced into the reaction system, the reaction was carried out at 140 °C, 400 rpm for 12 h, cooled, pressure relief, 2 mL of the reaction liquid was taken into the headspace bottle, and the conversion of propylene was 35%, the selectivity of 1,2- propylene oxide was 89%, and the yield of n-butyric acid was 38% by gas chromatography quantification.

[0040] Example 10

[0041] In a 100 mL stainless steel autoclave with a polytetrafluoroethylene liner, butyl butyrate 20 mL, cobalt chloride hexahydrate 0.0038 g (0.016 mmol), ethylenediaminetetraacetic acid 0.0292 g (0.1 mmol) were added, the autoclave was sealed, then propylene 0.33 g (8 mmol) was introduced by weighing. After that, air 0.95 g (32 mmol) was introduced into the reaction system, the reaction was carried out at 140 °C, 400 rpm for 12 h, cooled, pressure relief, 2 mL of the reaction liquid was taken into the headspace bottle, and the conversion of propylene was 35%, the selectivity of 1,2- propylene oxide was 89%, and the yield of n-butyric acid was 38% by gas chromatography quantification.

[0042] Table 1

[0043]

Claims

1. A process for the propene epoxidation to produce propylene oxide coproduct carboxylic acid characterized by, Propylene is used as raw material, ester solvent, catalyst, co-catalyst, 0.1-2 MPa air is introduced, and the reaction is carried out at 100-150℃ for 1-24 h to produce propylene oxide and by-product carboxylic acid compound corresponding to the structure of the ester solvent; the catalyst is one or more of FeCl3.6H2O, FeCl2.4H2O, CuCl2.2H2O, MnCl2.4H2O, BiCl3, NiCl3.6H2O, PPh3RuCl3, H2O and RuCl3, CoCl3.6H2O metal halide; the molar ratio of propylene, oxygen and ester compound is 1:(0.1-5):(5-50); the molar ratio of propylene, catalyst and co-catalyst is 1:0.0001-0.01:0.001-0.1; the co-catalyst is one or more of 4,4'-di-tert-butyl-2,2'-bipyridine, 1,3-bis(2,6-diisopropylphenyl)imidazolium chloride, tetramethyl ethylenediamine, imidazole, 2-methylimidazole, 5,6-dimethylphenanthroline and ethylenediaminetetraacetic acid; the ester solvent is one or more of ethyl acetate, methyl acetate, ethyl formate, isopropyl acetate, butyl acetate, sec-butyl acetate, hexyl acetate, ethyl tert-pentanoate, ethyl benzoate, dimethyl carbonate and diethyl carbonate.

2. The process for the preparation of propylene oxide for the production of oxirane and carboxylic acid as a by-product according to claim 1, characterized in that, the molar ratio of propylene, oxygen and ester compound is 1:(1-2):(10-25).

3. The process for the preparation of propylene oxide for the production of oxirane and carboxylic acid as a by-product according to claim 1, characterized in that, the molar ratio of propylene, catalyst and co-catalyst is 1:0.0016:0.0125.

4. The process for the preparation of propylene oxide for the production of oxirane and carboxylic acid as a by-product according to claim 1, characterized in that, the air introduction amount is 0.5-2 MPa.

5. The process for the preparation of propylene oxide for the production of oxirane and carboxylic acid as a by-product according to claim 1, characterized in that, the reaction time is 8-12 h.

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