Method and system for preparing propylene carbonate

Abstract

The invention relates to the technical field of preparation of propylene carbonate, and discloses a method and a system for preparing propylene carbonate. The method comprises the following steps: in the presence of a solid catalyst, propylene, H2, O2 and CO2 are subjected to a reaction, the molar ratio of propylene to H2 to O2 to CO2 is 1: (0.8-5): (0.8-5): (3-20), the solid catalyst comprises a titanium silicalite molecular sieve, an active component and a halogen-containing compound, the active component and the halogen-containing compound are loaded on the titanium silicalite molecular sieve, and the active component is gold. According to the method provided by the invention, propylene, H2, O2 and CO2 can be converted into propylene carbonate in one step by adopting a continuous synthesis process, and the selectivity of propylene carbonate is relatively high.

Description

Technical Field

[0001] The invention relates to the technical field of propylene carbonate preparation, and in particular to a method and system for preparing propylene carbonate. Background Art

[0002] Propylene carbonate is an important cyclic organic carbonate product in the new energy field. It has the advantages of low toxicity, high boiling point and good stability. It is widely used in key industries such as special environmentally friendly battery fluids and biodegradable materials. It is also used in the production of high-end chemical products such as dimethyl carbonate and propylene glycol.

[0003] At present, my country's propylene carbonate synthesis process faces the following technical difficulties: (1) The phosgene method is accompanied by the generation of a large amount of HCl, which seriously corrodes the equipment and has been eliminated; (2) The traditional urea alcoholysis method uses expensive propylene glycol as raw material, and low-temperature synthesis is limited by thermodynamics, while high-temperature conditions have high energy consumption; (3) CO 2 -The propylene oxide cycloaddition method is the most widely used, but the raw material propylene oxide is expensive and toxic, and its separation, purification, storage and transportation costs are also high. How to reduce the energy consumption and pollution of propylene carbonate synthesis and improve the process economy and environmental protection are major problems that the industry needs to solve urgently. In view of the above technical difficulties, it is urgent to develop a new generation of low-energy, high-efficiency and environmentally friendly propylene carbonate synthesis technology to improve my country's global competitiveness in the field of high-end chemical materials.

[0004] Starting from propylene and H 2 , O 2 , CO 2 The direct synthesis of propylene carbonate continuous reaction process belongs to the new generation of propylene carbonate synthesis technology. This technical route adopts a one-step continuous reaction process, which significantly simplifies the process, eliminates the peroxide oxidant, propylene oxide separation and purification and storage and transportation links, significantly reduces process energy consumption, and improves the economic efficiency of the whole process. In addition, the whole process generates nearly zero waste. After propylene epoxidation to generate propylene oxide, it reacts in situ with CO 2 The cycloaddition reaction to produce propylene carbonate solves the problems of poor selectivity and high separation cost in propylene oxide synthesis, as well as the high energy consumption of urea alcoholysis, poor intrinsic safety of epoxidation and cycloaddition reactions, and complex processes.

[0005] Patent application CN105348248B discloses a method of 2 A method for directly preparing propylene carbonate from propylene, comprising: reacting propylene, oxygen and CO 2 The reaction kettle containing metal porphyrin, composite surfactant and trimethylbenzene is introduced to react and prepare propylene carbonate. This method adopts an intermittent reaction process, and the production efficiency is low; the metal porphyrin catalyst used is an expensive homogeneous catalyst, which has high cost and is difficult to separate in the subsequent sequence, which limits the promotion of this technology.

[0006] Patent application CN106966862B discloses a method for simultaneously preparing propylene glycol and propylene carbonate. The method is divided into two steps: first, propylene is oxidized to propylene oxide under epoxidation conditions, and then the obtained propylene oxide, water, CO 2 The method also uses an intermittent reaction process and is divided into two steps. The process conditions need to be switched, which is time-consuming and laborious. Although there is no need to separate and purify propylene oxide, the process is still complicated. Two types of catalysts are required, the catalytic system is complicated, and the catalyst recycling is difficult.

[0007] Patent application CN112480058A discloses a production system for directly preparing cyclic carbonate from olefins and its application, the system comprises CO 2 The method uses a homogeneous catalytic system composed of a metal porphyrin complex and a co-catalyst. The method uses a bubbling tower as a reaction device, operates intermittently, and has low production efficiency. The reaction device is equipped with two distillation towers. Combined with the embodiment, the production system is more suitable for the reaction of high-boiling olefins such as styrene with CO 2 The cyclic carbonate is directly synthesized; and the expensive porphyrin complex homogeneous catalyst is used to carry out the reaction in an intermittent tower device, and the catalyst cost is relatively high. Summary of the invention

[0008] The object of the present invention is to provide a method and system for preparing propylene carbonate, in which propylene, H 2 , O 2 With CO 2 The direct continuous reaction to synthesize propylene carbonate significantly simplifies the process, eliminates the peroxide oxidant, propylene oxide separation and purification and storage and transportation links, and continuous production improves production efficiency; significantly reduces process energy consumption and improves the economy of the entire process; direct synthesis in one step, with the same process conditions throughout the process, avoids the problem of switching process conditions caused by different process conditions in the two-step method; and the solid catalyst used in the reaction process is easy to separate, solving the limitations of difficult separation and high cost of homogeneous catalysts; the preparation system is simple, which significantly reduces equipment investment.

[0009] In order to achieve the above object, the present invention provides a method for preparing propylene carbonate, which comprises: in the presence of a solid catalyst, propylene, H 2 , O 2 and CO 2 The reaction is carried out, wherein propylene, H 2 , O 2 and CO 2The molar ratio is 1:(0.8-5):(0.8-5):(3-20), the solid catalyst comprises a titanium silicon molecular sieve and an active component and a halogen-containing compound supported on the titanium silicon molecular sieve, wherein the active component is gold.

[0010] Preferably, in the solid catalyst, the content of the active component is 0.1-5 parts by weight, preferably 0.5-4 parts by weight, relative to 100 parts by weight of the titanium silicon molecular sieve; the content of the halogen-containing compound in terms of halogen element is 0.1-5 parts by weight, preferably 0.5-4 parts by weight.

[0011] Preferably, the titanium silicate molecular sieve is TS-1 titanium silicate molecular sieve.

[0012] Preferably, the halogen-containing compound is butylammonium bromide, propylammonium bromide, ZnBr 2 , KBr and KI.

[0013] Preferably, in the solid catalyst, the titanium silicon molecular sieve is also loaded with metal oxides.

[0014] Preferably, the content of the metal oxide is 0.1-5 parts by weight, preferably 0.5-4 parts by weight, relative to 100 parts by weight of the titanium silicon molecular sieve.

[0015] Preferably, the metal oxide is zinc oxide and / or magnesium oxide.

[0016] Preferably, the reaction temperature is 160-250°C.

[0017] Preferably, the reaction is carried out in a fixed bed reactor.

[0018] Preferably, the outlet pressure of the fixed bed reactor is 0.1-1 MPa, and the feed space velocity is 2000-12000 mL / (g cat h).

[0019] Preferably, propylene, H 2 , O 2 and CO 2 After being mixed in the gas mixing unit, the gases enter the fixed bed reactor for reaction.

[0020] Preferably, the method further comprises: performing gas-liquid separation on the reaction product of the fixed bed reactor, and returning the separated gas phase component to the gas mixing unit and / or the fixed bed reactor for recycling.

[0021] A second aspect of the present invention provides a system for preparing propylene carbonate, the system comprising:

[0022] The raw gas supply unit is used to supply propylene and H 2 , O 2 and CO 2 ;

[0023] A gas mixing unit for mixing propylene and H from the raw gas supply unit 2 , O 2 and CO 2 Mixing is performed;

[0024] A fixed bed reactor filled with a solid catalyst, through which the mixed gas from the gas mixing unit is reacted, wherein the solid catalyst comprises a titanium silicon molecular sieve and an active component and a halogen-containing compound supported on the titanium silicon molecular sieve;

[0025] A gas-liquid separation unit, used for performing gas-liquid separation on the reaction product of the fixed bed reactor;

[0026] The raw gas circulation unit is used to return the gas phase components separated in the gas-liquid separation unit to the gas mixing unit and / or the fixed bed reactor for recycling.

[0027] Compared with the prior art, the method and system for preparing propylene carbonate of the present invention have the following advantages:

[0028] (1) The present invention adopts a continuous synthesis process to synthesize propylene and H 2 , O 2 With CO 2 One-step conversion to propylene carbonate with high selectivity for propylene carbonate;

[0029] (2) The solid catalyst used in the present invention is easy to separate and reuse, and the overall cost is low;

[0030] (3) In the present invention, propylene carbonate can be directly synthesized in one reactor, while in the prior art, the reaction generally needs to be carried out in two steps, and the two steps use different catalysts and different reaction conditions, and different reaction conditions need to be switched;

[0031] (4) Compared with the traditional two-step method for synthesizing propylene carbonate, the method of the present invention significantly simplifies the process, eliminates the steps of separation, purification, storage and transportation of propylene oxide, significantly reduces process energy consumption, and improves the economy of the entire process. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of a system for preparing propylene carbonate provided by the present invention.

[0033] Description of Reference Numerals

[0034] 1. Gas mixing unit; 2. Fixed bed reactor; 3. Gas-liquid separation unit; 4. Raw gas circulation unit. DETAILED DESCRIPTION

[0035] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0036] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0037] The method for preparing propylene carbonate of the present invention comprises: in the presence of a solid catalyst, propylene, H 2 , O 2 and CO 2 to react.

[0038] In the method described in the present invention, propylene, H 2 , O 2 and CO 2 The molar ratio is 1: (0.8-5): (0.8-5): (3-20), preferably 1: (0.9-2): (0.9-2): (4-10).

[0039] In the method described in the present invention, the solid catalyst comprises titanium silicon molecular sieve and active components and halogen-containing compounds supported on the titanium silicon molecular sieve, wherein the active component is gold.

[0040] In the solid catalyst, the content of the active component can be 0.1-5 parts by weight, preferably 0.5-4 parts by weight, relative to 100 parts by weight of the titanium silicon molecular sieve, and specifically can be, for example, 0.5 parts by weight, 0.8 parts by weight, 1 part by weight, 1.3 parts by weight, 1.5 parts by weight, 1.8 parts by weight, 2 parts by weight, 2.3 parts by weight, 2.5 parts by weight, 2.8 parts by weight, 3 parts by weight, 3.2 parts by weight, 3.5 parts by weight, 3.7 parts by weight or 4 parts by weight.

[0041] In the solid catalyst, the content of the halogen-containing compound is calculated as halogen content. Relative to 100 parts by weight of the titanium silicon molecular sieve, the content of the halogen-containing compound in terms of halogen element can be 0.1-5 parts by weight, preferably 0.5-4 parts by weight, and specifically, for example, can be 0.5 parts by weight, 0.8 parts by weight, 1 part by weight, 1.3 parts by weight, 1.5 parts by weight, 1.8 parts by weight, 2 parts by weight, 2.3 parts by weight, 2.5 parts by weight, 2.8 parts by weight, 3 parts by weight, 3.2 parts by weight, 3.5 parts by weight, 3.7 parts by weight or 4 parts by weight.

[0042] In the present invention, the titanium silicalite molecular sieve may be a titanium silicalite molecular sieve having a multi-level pore structure (such as micropores and mesopores). In a preferred embodiment, in order to obtain a higher selectivity for propylene carbonate, the titanium silicalite molecular sieve is a TS-1 titanium silicalite molecular sieve.

[0043] In the present invention, the halogen-containing compound may be butylammonium bromide, propylammonium bromide, ZnBr 2 In a preferred embodiment, the halogen-containing compound is butylammonium bromide and / or propylammonium bromide.

[0044] In a more preferred embodiment, in the solid catalyst, the titanium silicon molecular sieve is also loaded with a metal oxide. According to this preferred embodiment, in the reaction process of preparing propylene carbonate, the metal oxide can synergize with the halogen-containing compound, thereby further improving the selectivity of the target product.

[0045] When the solid catalyst also contains metal oxide, the content of the metal oxide is 0.1-5 parts by weight, preferably 0.5-4 parts by weight, relative to 100 parts by weight of the titanium silicon molecular sieve. Specifically, it can be 0.5 parts by weight, 0.8 parts by weight, 1 part by weight, 1.3 parts by weight, 1.5 parts by weight, 1.8 parts by weight, 2 parts by weight, 2.3 parts by weight, 2.5 parts by weight, 2.8 parts by weight, 3 parts by weight, 3.2 parts by weight, 3.5 parts by weight, 3.7 parts by weight or 4 parts by weight.

[0046] In the present invention, the metal oxide is preferably zinc oxide and / or magnesium oxide.

[0047] In the present invention, the preparation method of the solid catalyst may include: (1) immersing the titanium silicon molecular sieve in a solution containing an active component precursor and an optional metal oxide precursor, keeping it still in the dark, drying, optionally calcining, and then reducing to obtain a catalyst intermediate; (2) loading a halogen-containing compound on the catalyst intermediate to obtain the solid catalyst.

[0048] In some embodiments, when the solid catalyst includes a titanium silicalite and an active component and a halogen-containing compound loaded on the titanium silicalite, the halogen-containing compound is butylammonium bromide and / or propylammonium bromide, and no metal oxide is loaded on the titanium silicalite, the preparation process of the solid catalyst includes: immersing the titanium silicalite in a solution containing an active component precursor (such as chloroauric acid), and then standing in a dark place, drying and reducing in sequence to obtain a catalyst intermediate; in the presence of an organic solvent (such as toluene), reacting the catalyst intermediate, 3-(aminopropyl)triethoxysilane and n-butyl bromide and / or n-propyl bromide under reflux conditions, collecting the solid after the reaction, washing, and drying to obtain the solid catalyst.

[0049] In other embodiments, when the solid catalyst includes titanium silicon molecular sieve and active components, metal oxides and halogen-containing compounds loaded on the titanium silicon molecular sieve, and the halogen-containing compound is butyl ammonium bromide and / or propyl ammonium bromide, the preparation process of the solid catalyst includes: immersing the titanium silicon molecular sieve in a solution containing an active component precursor (such as chloroauric acid) and a metal oxide precursor (such as zinc nitrate, magnesium nitrate, etc.), and then standing in the dark, drying, calcining and reducing in sequence to obtain a catalyst intermediate; in the presence of an organic solvent (such as toluene), reacting the catalyst intermediate, 3-(aminopropyl)triethoxysilane and n-butyl bromide and / or n-propyl bromide under reflux conditions, and after the reaction, collecting the solid, washing and drying to obtain the solid catalyst.

[0050] In the method described in the present invention, propylene, H 2 , O 2 and CO 2 The reaction temperature for preparing propylene carbonate is preferably 160-250°C, more preferably 180-220°C.

[0051] In the method described in the present invention, propylene, H 2 , O 2 and CO 2 The reaction process for preparing propylene carbonate is preferably carried out in a fixed bed reactor. In this case, the solid catalyst is loaded in the fixed bed reactor as a catalyst bed. In the actual operation, propylene, H 2 , O 2 and CO 2 The mixed gas passes through the catalyst bed in the fixed bed reactor from top to bottom.

[0052] When the reaction is carried out in a fixed bed reactor, the outlet pressure of the fixed bed reactor may be 0.1-1 MPa, and the feed space velocity may be 2000-12000 mL / (g cath). In the present invention, pressure refers to absolute pressure.

[0053] In the method of the present invention, in a preferred case, propylene, H 2 , O 2 and CO 2 After being mixed in the gas mixing unit, the gases enter the fixed bed reactor for reaction.

[0054] In the present invention, in a preferred case, the method for preparing propylene carbonate further comprises: performing gas-liquid separation on the reaction product of the fixed bed reactor, and returning the separated gas phase component to the gas mixing unit and / or the fixed bed reactor for recycling. The gas-liquid separation process can be implemented in a gas-liquid separation tank, and the pressure in the gas-liquid separation tank is preferably 1 atmosphere during gas-liquid separation. More preferably, a defoamer is provided at the upper 1 / 5 of the gas-liquid separation tank to prevent the gas phase material from carrying liquid when the gas velocity is too fast.

[0055] In some specific embodiments, the method for preparing propylene carbonate comprises:

[0056] (1) Propylene, H 2 , O 2 and CO 2 Mix in the gas mixing unit to obtain propylene, H 2 , O 2 and CO 2 A mixed gas of propylene, H 2 , O 2 and CO 2 The molar ratio is 1: (0.8-5): (0.8-5): (3-20);

[0057] (2) introducing the mixed gas into a fixed bed reactor to react at 160-250° C., wherein the fixed bed reactor is loaded with a solid catalyst as a catalyst bed, and the solid catalyst comprises a titanium silicon molecular sieve and an active component, a halogen-containing compound and an optional metal oxide supported on the titanium silicon molecular sieve, wherein the active component is gold;

[0058] (3) separating the reaction product of the fixed bed reactor into gas and liquid, and returning the separated gas phase component to the gas mixing unit and / or the fixed bed reactor for recycling.

[0059] In other specific embodiments, the method for preparing propylene carbonate comprises:

[0060] (1) Propylene, H 2 , O 2 and CO 2 Mix in the gas mixing unit to obtain propylene, H2 , O 2 and CO 2 A mixed gas of propylene, H 2 , O 2 and CO 2 The molar ratio is 1:(0.9-2):(0.9-2):(4-10);

[0061] (2) The mixed gas is introduced into a fixed bed reactor and reacted at 180-220° C. The outlet pressure of the fixed bed reactor is 0.1-1 MPa, and the raw material space velocity is 2000-12000 mL / (g cat h), wherein the fixed bed reactor is loaded with a solid catalyst as a catalyst bed, wherein the solid catalyst comprises a titanium silicon molecular sieve and an active component supported on the titanium silicon molecular sieve, a halogen-containing compound and an optional metal oxide, wherein the active component is gold, and the halogen-containing compound is tetrabutylammonium bromide, tetrapropylammonium bromide, ZnBr 2 , at least one of KBr and KI, wherein the metal oxide is zinc oxide and / or magnesium oxide;

[0062] (3) separating the reaction product of the fixed bed reactor into gas and liquid, and returning the separated gas phase component to the gas mixing unit and / or the fixed bed reactor for recycling.

[0063] like Figure 1 As shown, the system for preparing propylene carbonate of the present invention comprises:

[0064] The raw gas supply unit is used to supply propylene and H 2 , O 2 and CO 2 ;

[0065] A gas mixing unit 1 is used to mix propylene and H from the raw gas supply unit. 2 , O 2 and CO 2 Mixing is performed;

[0066] A fixed bed reactor 2, which is filled with a solid catalyst, through which the mixed gas from the gas mixing unit is reacted, wherein the solid catalyst comprises a titanium silicon molecular sieve and an active component and a halogen-containing compound supported on the titanium silicon molecular sieve;

[0067] A gas-liquid separation unit 3, used for performing gas-liquid separation on the reaction product of the fixed bed reactor;

[0068] The raw gas circulation unit 4 is used to return the gas phase components separated in the gas-liquid separation unit to the gas mixing unit and / or the fixed bed reactor for recycling.

[0069] In the system of the present invention, the raw gas supply unit can deliver raw gas, specifically, propylene and H2, to the gas mixing unit 1 through two feed pipelines. 2 The mixed gas is fed through a pipeline, O 2 and CO 2 The mixed gas is fed through another pipeline.

[0070] In the system described in the present invention, the gas mixing unit 1 may be a gas static mixer.

[0071] In the system described in the present invention, the fixed bed reactor 2 is a downward fixed bed reactor. The gas mixing unit 1 is connected to the fixed bed reactor 2 through a pipeline, and the mixed gas from the gas mixing unit 1 enters the downward fixed bed reactor by self-pressure, and passes through the catalyst bed in the fixed bed reactor from top to bottom. Preferably, a one-way valve is provided on the connecting pipeline between the gas mixing unit 1 and the fixed bed reactor 2 to prevent the material in the fixed bed reactor from being reversed.

[0072] In the system described in the present invention, the gas-liquid separation unit 3 can be a gas-liquid separation tank. The top and bottom of the gas-liquid separation tank are respectively provided with a discharge port, and the gas phase material is produced from the top discharge port, and the liquid phase material is produced from the bottom discharge port. Preferably, a defoamer is provided at the upper 1 / 5 of the gas-liquid separation tank to prevent the gas phase material from carrying liquid when the gas velocity is too fast.

[0073] In the system described in the present invention, the raw gas circulation unit 4 can be a high-pressure pump, which is used to inject the gaseous material extracted from the top outlet of the gas-liquid separation tank into the gas mixing unit and / or the fixed bed reactor to achieve the recycling of unreacted materials.

[0074] In the present invention, preferably, each device in the system is made of 316L stainless steel.

[0075] In some specific embodiments, the method for preparing propylene carbonate described above is implemented in the above system. Specifically, the method includes:

[0076] Propylene, H 2 , O 2 and CO 2 The raw material is respectively transported to the gas mixing unit 1 through the raw material supply unit for mixing to obtain propylene, H 2 , O 2 and CO 2A mixed gas of propylene, H 2 , O 2 and CO 2 The molar ratio is 1: (0.8-5): (0.8-5): (3-20);

[0077] The mixed gas from the gas mixing unit 1 is introduced into the fixed bed reactor 2 to react at 160-250° C., wherein the fixed bed reactor is filled with a solid catalyst as a catalyst bed, and the solid catalyst includes a titanium silicon molecular sieve and an active component, a halogen-containing compound and an optional metal oxide supported on the titanium silicon molecular sieve, wherein the active component is gold, and the halogen-containing compound is tetrabutylammonium bromide, tetrapropylammonium bromide, ZnBr 2 , at least one of KBr and KI, wherein the metal oxide is zinc oxide and / or magnesium oxide;

[0078] The reaction product of the fixed bed reactor 2 is transported to the gas-liquid separation unit 3 for gas-liquid separation, and a crude propylene carbonate product (i.e., a crude PC product) is obtained from the separated liquid phase;

[0079] The gas phase components separated from the gas-liquid separation unit 3 are returned to the gas mixing unit and / or the fixed bed reactor through the raw gas circulation unit 4 for recycling.

[0080] The following examples further illustrate the method and system for preparing propylene carbonate of the present invention. The examples are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes, but the protection scope of the present invention is not limited to the following examples.

[0081] The experimental methods in the following examples, unless otherwise specified, are all conventional methods in the art. The experimental materials used in the following examples, unless otherwise specified, are all commercially available.

[0082] Example 1

[0083] (1) Preparation of solid catalyst

[0084] Weigh 0.5g of chloroauric acid (III) hydrate and dissolve it in 10mL of water for later use, weigh 5g of TS-1 titanium silicon molecular sieve and place it in a 20mL brown glass bottle, use a pipette to take 5mL of chloroauric acid aqueous solution and disperse it on the TS-1 titanium silicon molecular sieve in the brown bottle, cover the bottle cap, keep it at room temperature away from light for 12h, and then place it in a 70℃ oven to dry. The obtained sample was reduced in a hydrogen-nitrogen mixed gas (hydrogen content of 10 volume%) at 300℃ for 5h to obtain a catalyst intermediate.

[0085] Weigh 2.0 g of the catalyst intermediate and place it in a 200 ml round-bottom flask. Add 50 ml of toluene and 1.2 g of 3-(Aminopropyl)triethoxysilane; a reflux condenser is inserted into the middle opening of a three-necked flask, one of the side openings is plugged with a stopper, and the other opening is plugged with a rubber stopper with an air guide tube, and nitrogen is introduced into the air guide tube to replace the air in the three-necked flask and the reflux condenser; the three-necked flask is heated in an oil bath, and the temperature is raised to 110°C and then refluxed at a constant temperature for 12 hours; 2.01g of n-butyl bromide is added to the three-necked flask, and refluxed at a constant temperature of 110°C for 24 hours; after the reaction is completed, the solid is collected, washed three times with dichloromethane and anhydrous ethanol in sequence, and dried at 70°C for 12 hours to obtain a solid catalyst Cat-1, wherein, according to the tests by inductively coupled plasma emission spectrometry and ion chromatography, the gold content is 2.8 parts by weight, and the butyl ammonium bromide content is 2.0 parts by weight in terms of bromine element relative to 100 parts by weight of TS-1 titanium silicalite molecular sieve.

[0086] (2) Synthesis of Propylene Carbonate

[0087] This embodiment Figure 1 In the system shown in FIG. 1 , propylene, H 2 , O 2 and CO 2 The gas is continuously introduced into the gas mixing unit according to a certain ratio to mix them evenly, wherein propylene / H 2 / O 2 / CO 2 The molar ratio is 3 / 3 / 3 / 16, and the pressure of the gas mixing unit is 0.5MPa. The mixed raw material gas is pressed into the descending fixed bed reactor filled with solid catalyst Cat-1 by self-pressure. The outlet pressure of the fixed bed reactor is 0.1MPa, and the raw material space velocity is 8000mL / (g cat h), reaction temperature 200°C; the reaction products come out of the downward fixed bed reactor and enter the gas-liquid separation tank for separation, and the gas phase components (unreacted propylene, H 2 , O 2 and CO 2 ) are sampled and analyzed, and the rest are pumped into the gas mixing unit for recycling. The liquid component (crude propylene carbonate) is taken from the bottom of the gas-liquid separation tank for analysis.

[0088] Quantitative analysis and calculation by gas chromatography (equipped with HP-1 chromatographic column) revealed that the single-pass conversion of propylene was 8.3% and the selectivity of propylene carbonate was 86.5%.

[0089] Example 2

[0090] (1) Preparation of solid catalyst

[0091] A solid catalyst was prepared according to the method of Example 1, except that the amount of raw materials was adjusted so that in the prepared solid catalyst Cat-2, the gold content was 3.2 parts by weight relative to 100 parts by weight of TS-1 titanium silicalite molecular sieve, and the content of butylammonium bromide in terms of bromine element was 1.2 parts by weight.

[0092] (2) Synthesis of Propylene Carbonate

[0093] This embodiment Figure 1 In the system shown in FIG. 1 , propylene, H 2 , O 2 and CO 2 The gas is continuously introduced into the gas mixing unit according to a certain ratio to mix them evenly, wherein propylene / H 2 / O 2 / CO 2 The molar ratio is 1 / 1 / 1 / 7, and the pressure of the gas mixing unit is 0.5MPa; the mixed raw material gas is pressed into the descending fixed bed reactor filled with solid catalyst Cat-2 by self-pressure, the outlet pressure of the fixed bed reactor is 0.3MPa, and the raw material space velocity is 8000mL / (g cat h), reaction temperature 200°C; the reaction products come out of the downward fixed bed reactor and enter the gas-liquid separation tank for separation, and the gas phase components (unreacted propylene, H 2 , O 2 and CO 2 ) are sampled and analyzed, and the rest are pumped into the gas mixing unit for recycling. The liquid component (crude propylene carbonate) is taken from the bottom of the gas-liquid separation tank for analysis.

[0094] Quantitative analysis and calculation by gas chromatography (equipped with HP-1 chromatographic column) revealed that the single-pass conversion of propylene was 9.1% and the selectivity of propylene carbonate was 85.2%.

[0095] Example 3

[0096] (1) Preparation of solid catalyst

[0097] A solid catalyst was prepared according to the method of Example 1, except that the amount of raw materials was adjusted so that in the prepared solid catalyst Cat-3, the gold content was 1.8 parts by weight relative to 100 parts by weight of TS-1 titanium silicalite molecular sieve, and the content of butylammonium bromide in terms of bromine element was 2.7 parts by weight.

[0098] (2) Synthesis of Propylene Carbonate

[0099] This embodiment Figure 1 In the system shown in FIG. 1 , propylene, H 2 , O 2 and CO 2The gas is continuously introduced into the gas mixing unit according to a certain ratio to mix them evenly, wherein propylene / H 2 / O 2 / CO 2 The molar ratio is 1 / 1 / 1 / 6, and the pressure of the gas mixing unit is 0.5MPa. The mixed raw material gas is pressed into the descending fixed bed reactor filled with solid catalyst Cat-3 by self-pressure. The outlet pressure of the fixed bed reactor is 0.4MPa, and the raw material space velocity is 8000mL / (g cat h), reaction temperature 200°C; the reaction products come out of the downward fixed bed reactor and enter the gas-liquid separation tank for separation, and the gas phase components (unreacted propylene, H 2 , O 2 and CO 2 ) are sampled and analyzed, and the rest are pumped into the gas mixing unit for recycling. The liquid component (crude propylene carbonate) is taken from the bottom of the gas-liquid separation tank for analysis.

[0100] Quantitative analysis and calculation by gas chromatography (equipped with HP-1 chromatographic column) revealed that the single-pass conversion of propylene was 8.5% and the selectivity of propylene carbonate was 87.1%.

[0101] Example 4

[0102] (1) Preparation of solid catalyst

[0103] A solid catalyst was prepared according to the method of Example 1, except that 1.80 g of n-propane bromide was used instead of n-butane bromide to obtain a solid catalyst Cat-4, wherein the gold content was 2.8 parts by weight relative to 100 parts by weight of TS-1 titanium silicalite molecular sieve, and the content of propylammonium bromide in terms of bromine element was 2.0 parts by weight.

[0104] (2) Synthesis of Propylene Carbonate

[0105] This embodiment Figure 1 In the system shown in FIG. 1 , propylene, H 2 , O 2 and CO 2 The gas is continuously introduced into the gas mixing unit according to a certain ratio to mix them evenly, wherein propylene / H 2 / O 2 / CO 2 The molar ratio is 1 / 1 / 1 / 5, and the pressure of the gas mixing unit is 0.5MPa. The mixed raw material gas is pressed into a descending fixed bed reactor filled with solid catalyst Cat-4 by self-pressure. The outlet pressure of the fixed bed reactor is 0.2MPa, and the raw material space velocity is 8000mL / (g cat h), reaction temperature 180°C; the reaction products come out of the downward fixed bed reactor and enter the gas-liquid separation tank for separation, and the gas phase components (unreacted propylene, H 2, O 2 and CO 2 ) are sampled and analyzed, and the rest are pumped into the gas mixing unit for recycling. The liquid component (crude propylene carbonate) is taken from the bottom of the gas-liquid separation tank for analysis.

[0106] Quantitative analysis and calculation by gas chromatography (equipped with HP-1 chromatographic column) revealed that the single-pass conversion of propylene was 8.1% and the selectivity of propylene carbonate was 88.2%.

[0107] Example 5

[0108] (1) Preparation of solid catalyst

[0109] Weigh 0.5g of chloroauric acid (III) hydrate and 0.38g of magnesium nitrate hexahydrate and dissolve them in 10mL of water for later use, weigh 5g of TS-1 titanium silicon molecular sieve and place it in a 20mL brown glass bottle, use a pipette to take 5mL of chloroauric acid and magnesium nitrate aqueous solution and disperse and drop them on the TS-1 titanium silicon molecular sieve in the brown bottle, cover the bottle cap, stand at room temperature in the dark for 12h, and then place it in a 70℃ oven to dry. The obtained sample was calcined at 400℃ in air atmosphere for 5h, and then the obtained sample was reduced at 300℃ in hydrogen and nitrogen mixed gas (hydrogen content is 10 volume%) for 5h to obtain a catalyst intermediate.

[0110] Weigh 2.0 g of the catalyst intermediate and place it in a 200 ml round-bottom flask. Add 50 ml of toluene and 1.2 g of 3-(Aminopropyl)triethoxysilane; a reflux condenser is inserted into the middle opening of a three-necked flask, one of the side openings is plugged with a stopper, and the other opening is plugged with a rubber stopper with an air guide tube, and nitrogen is introduced into the air guide tube to replace the air in the three-necked flask and the reflux condenser; the three-necked flask is heated in an oil bath, and the temperature is raised to 110°C and then refluxed at a constant temperature for 12 hours; 2.01g of n-butyl bromide is added to the three-necked flask, and refluxed at a constant temperature of 110°C for 24 hours; after the reaction is completed, the solid is collected, washed three times with dichloromethane and anhydrous ethanol in sequence, and dried at 70°C for 12 hours to obtain a solid catalyst Cat-5, wherein, according to the tests by inductively coupled plasma emission spectrometer and ion chromatography, the content of gold is 2.8 parts by weight, the content of magnesium oxide is 0.6 parts by weight, and the content of butyl ammonium bromide in terms of bromine element is 2.0 parts by weight relative to 100 parts by weight of TS-1 titanium silicon molecular sieve.

[0111] (2) Synthesis of Propylene Carbonate

[0112] This embodiment Figure 1 In the system shown in FIG. 1 , propylene, H 2 , O 2 and CO 2 The gas is continuously introduced into the gas mixing unit according to a certain ratio to mix them evenly, wherein propylene / H2 / O 2 / CO 2 The molar ratio is 3 / 3 / 3 / 16, and the pressure of the gas mixing unit is 0.5MPa. The mixed raw material gas is pressed into the descending fixed bed reactor filled with solid catalyst Cat-5 by self-pressure. The outlet pressure of the fixed bed reactor is 0.1MPa, and the raw material space velocity is 12000mL / (g cat h), reaction temperature 220°C; the reaction products come out of the downward fixed bed reactor and enter the gas-liquid separation tank for separation, and the gas phase components (unreacted propylene, H 2 , O 2 and CO 2 ) are sampled and analyzed, and the rest are pumped into the gas mixing unit for recycling. The liquid component (crude propylene carbonate) is taken from the bottom of the gas-liquid separation tank for analysis.

[0113] Quantitative analysis and calculation by gas chromatography (equipped with HP-1 chromatographic column) revealed that the single-pass conversion of propylene was 8.3% and the selectivity of propylene carbonate was 91.5%.

[0114] Example 6

[0115] (1) Preparation of solid catalyst

[0116] A solid catalyst was prepared according to the method of Example 5, except that zinc nitrate hexahydrate was used instead of magnesium nitrate hexahydrate, and the amount of raw materials was adjusted so that in the prepared solid catalyst Cat-6, relative to 100 parts by weight of TS-1 titanium silicon molecular sieve, the content of gold was 3.4 parts by weight, the content of zinc oxide was 0.8 parts by weight, and the content of butyl ammonium bromide in terms of bromine element was 1.3 parts by weight.

[0117] (2) Synthesis of Propylene Carbonate

[0118] This embodiment Figure 1 In the system shown in FIG. 1 , propylene, H 2 , O 2 and CO 2 The gas is continuously introduced into the gas mixing unit according to a certain ratio to mix them evenly, wherein propylene / H 2 / O 2 / CO 2 The molar ratio is 3 / 3 / 3 / 16, and the pressure of the gas mixing unit is 0.5MPa. The mixed raw material gas is pressed into the descending fixed bed reactor filled with solid catalyst Cat-6 by self-pressure. The outlet pressure of the fixed bed reactor is 0.1MPa, and the raw material space velocity is 4000mL / (g cat h), reaction temperature 200°C; the reaction products come out of the downward fixed bed reactor and enter the gas-liquid separation tank for separation, and the gas phase components (unreacted propylene, H 2 , O2 and CO 2 ) are sampled and analyzed, and the rest are pumped into the gas mixing unit for recycling. The liquid component (crude propylene carbonate) is taken from the bottom of the gas-liquid separation tank for analysis.

[0119] Quantitative analysis and calculation by gas chromatography (equipped with HP-1 chromatographic column) revealed that the single-pass conversion of propylene was 9.5% and the selectivity of propylene carbonate was 93.6%.

[0120] Example 7

[0121] (1) Preparation of solid catalyst

[0122] A solid catalyst was prepared according to the method of Example 5, except that n-propane bromide was used instead of n-butane bromide, and the amount of raw materials was adjusted so that in the prepared solid catalyst Cat-7, the gold content was 1.7 parts by weight, the zinc oxide content was 1.2 parts by weight, and the propylammonium bromide content in terms of bromine element was 2.6 parts by weight, relative to 100 parts by weight of TS-1 titanium silicalite molecular sieve.

[0123] (2) Synthesis of Propylene Carbonate

[0124] This embodiment Figure 1 In the system shown in FIG. 1 , propylene, H 2 , O 2 and CO 2 The gas is continuously introduced into the gas mixing unit according to a certain ratio to mix them evenly, wherein propylene / H 2 / O 2 / CO 2 The molar ratio is 3 / 3 / 3 / 16, and the pressure of the gas mixing unit is 0.5MPa. The mixed raw material gas is pressed into the descending fixed bed reactor filled with solid catalyst Cat-7 by self-pressure. The outlet pressure of the fixed bed reactor is 0.1MPa, and the raw material space velocity is 8000mL / (g cat h), reaction temperature 200°C; the reaction products come out of the downward fixed bed reactor and enter the gas-liquid separation tank for separation, and the gas phase components (unreacted propylene, H 2 , O 2 and CO 2 ) are sampled and analyzed, and the rest are pumped into the gas mixing unit for recycling. The liquid component (crude propylene carbonate) is taken from the bottom of the gas-liquid separation tank for analysis.

[0125] Quantitative analysis and calculation by gas chromatography (equipped with HP-1 chromatographic column) revealed that the single-pass conversion of propylene was 7.9% and the selectivity of propylene carbonate was 92.1%.

[0126] Comparative Example 1

[0127] Propylene carbonate was synthesized according to the method of Example 1, except that the same molar amount of N 2 Replacement of CO 2 .

[0128] Quantitative analysis and calculation by gas chromatography (equipped with HP-1 chromatographic column) revealed that the single-pass conversion of propylene was 7.1% and the selectivity of propylene carbonate was 0%.

[0129] Comparative Example 2

[0130] The solid catalyst was prepared and propylene carbonate was synthesized according to the method of Example 1, except that the catalyst intermediate prepared in Example 1 was directly used as the solid catalyst D1 (that is, the solid catalyst was not loaded with a halogen-containing compound); and in the process of synthesizing propylene carbonate, the solid catalyst loaded in the fixed bed reactor was the solid catalyst D1.

[0131] Quantitative analysis and calculation by gas chromatography (equipped with HP-1 chromatographic column) revealed that the single-pass conversion of propylene was 7.2% and the selectivity of propylene carbonate was 6.3%.

[0132] Comparative Example 3

[0133] Propylene carbonate was synthesized according to the method of Example 1, except that the solid catalyst loaded in the fixed bed reactor was zinc bromide.

[0134] Quantitative analysis and calculation by gas chromatography (equipped with HP-1 chromatographic column) revealed that the single-pass conversion rate of propylene was 0%.

[0135] Comparative Example 4

[0136] Propylene carbonate was synthesized according to the method of Example 1, except that propylene, H 2 , O 2 and CO 2 Input according to the molar ratio of 1 / 1 / 1 / 2.

[0137] Quantitative analysis and calculation by gas chromatography (equipped with HP-1 chromatographic column) revealed that a slight deflagration occurred in the fixed bed reactor.

[0138] Comparative Example 5

[0139] Propylene carbonate was synthesized according to the method of Example 1, except that H 2 .

[0140] Quantitative analysis and calculation by gas chromatography (equipped with HP-1 chromatographic column) revealed that the single-pass conversion of propylene was 0.8% and the selectivity of propylene carbonate was 0%.

[0141] Comparative Example 6

[0142] Propylene carbonate was synthesized according to the method of Example 1, except that O 2 .

[0143] Quantitative analysis and calculation by gas chromatography (equipped with HP-1 chromatographic column) revealed that the single-pass conversion of propylene was 0.3% and the selectivity of propylene carbonate was 0%.

[0144] Comparative Example 7

[0145] The solid catalyst was prepared and propylene carbonate was synthesized according to the method of Example 5, except that the catalyst intermediate prepared in Example 5 was directly used as the solid catalyst D2 (that is, the solid catalyst was not loaded with halogen-containing compounds); and in the process of synthesizing propylene carbonate, the solid catalyst loaded in the fixed bed reactor was the solid catalyst D2.

[0146] Quantitative analysis and calculation by gas chromatography (equipped with HP-1 chromatographic column) revealed that the single-pass conversion of propylene was 7.3% and the selectivity of propylene carbonate was 13.2%.

[0147] Comparative Example 8

[0148] The solid catalyst was prepared and propylene carbonate was synthesized according to the method of Example 5, except that, in the process of preparing the solid catalyst, chloroauric acid (III) hydrate was not added to obtain solid catalyst D3 (that is, no gold was loaded in the solid catalyst); and, in the process of synthesizing propylene carbonate, the solid catalyst loaded in the fixed bed reactor was solid catalyst D3.

[0149] Quantitative analysis and calculation by gas chromatography (equipped with HP-1 chromatographic column) revealed that the single-pass conversion of propylene was 0.4% and the selectivity of propylene carbonate was 0%.

[0150] Comparative Example 9

[0151] The solid catalyst was prepared and propylene carbonate was synthesized according to the method of Example 5, except that, in the process of preparing the solid catalyst, S-1 pure silicon molecular sieve was used instead of TS-1 titanium silicon molecular sieve to obtain solid catalyst D4; and, in the process of synthesizing propylene carbonate, the solid catalyst loaded in the fixed bed reactor was solid catalyst D4.

[0152] Quantitative analysis and calculation by gas chromatography (equipped with HP-1 chromatographic column) revealed that the single-pass conversion of propylene was 4.3% and the selectivity of propylene carbonate was 3.1%.

[0153] It can be seen from the results of the above examples and comparative examples that the method according to the present invention achieves the use of a continuous synthesis process for the synthesis of propylene, H 2 , O 2 With CO 2It is converted into propylene carbonate in one step, and the selectivity of propylene carbonate is high.

[0154] 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 method for preparing propylene carbonate, It is characterized in that The method comprises: in the presence of a solid catalyst, propylene, H 2 , O 2 and CO 2 The reaction is carried out, wherein propylene, H 2 , O 2 and CO 2 The molar ratio is 1:(0.8-5):(0.8-5):(3-20), the solid catalyst comprises a titanium silicon molecular sieve and an active component and a halogen-containing compound supported on the titanium silicon molecular sieve, wherein the active component is gold.

2. The method according to claim 1, It is characterized in that In the solid catalyst, relative to 100 parts by weight of the titanium silicon molecular sieve, the content of the active component is 0.1-5 parts by weight, preferably 0.5-4 parts by weight; the content of the halogen-containing compound in terms of halogen element is 0.1-5 parts by weight, preferably 0.5-4 parts by weight.

3. The method according to claim 1 or 2, It is characterized in that The titanium silicate molecular sieve is TS-1 titanium silicate molecular sieve.

4. The method according to claim 1 or 2, It is characterized in that The halogen-containing compound is butylammonium bromide, propylammonium bromide, ZnBr 2 , KBr and KI.

5. The method according to any one of claims 1 to 4, It is characterized in that In the solid catalyst, the titanium silicon molecular sieve is also loaded with metal oxides; Preferably, relative to 100 parts by weight of the titanium silicon molecular sieve, the content of the metal oxide is 0.1-5 parts by weight, preferably 0.5-4 parts by weight; Preferably, the metal oxide is zinc oxide and / or magnesium oxide.

6. The method according to any one of claims 1 to 5, It is characterized in that The reaction temperature is 160-250°C.

7. The method according to any one of claims 1 to 6, It is characterized in that The reaction is carried out in a fixed bed reactor.

8. The method according to claim 7, It is characterized in that The outlet pressure of the fixed bed reactor is 0.1-1 MPa, and the raw material space velocity is 2000-12000 mL / (g cat h).

9. The method according to claim 7 or 8, It is characterized in that Propylene, H 2 , O 2 and CO 2 After being mixed in the gas mixing unit, the gases enter the fixed bed reactor for reaction.

10. The method according to claim 9, It is characterized in that The method further comprises: performing gas-liquid separation on the reaction product of the fixed bed reactor, and returning the separated gas phase component to the gas mixing unit and / or the fixed bed reactor for recycling.

11. A system for preparing propylene carbonate, It is characterized in that The system includes: The raw gas supply unit is used to supply propylene and H 2 , O 2 and CO 2 ; A gas mixing unit for mixing propylene and H from the raw gas supply unit 2 , O 2 and CO 2 Mixing is performed; A fixed bed reactor filled with a solid catalyst, through which the mixed gas from the gas mixing unit is reacted, wherein the solid catalyst comprises a titanium silicon molecular sieve and an active component and a halogen-containing compound supported on the titanium silicon molecular sieve; A gas-liquid separation unit, used for performing gas-liquid separation on the reaction product of the fixed bed reactor; The raw gas circulation unit is used to return the gas phase components separated in the gas-liquid separation unit to the gas mixing unit and / or the fixed bed reactor for recycling.

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