Solid catalyst for preparing propylene carbonate and preparation method thereof

Abstract

The invention relates to the technical field of preparation of propylene carbonate, and discloses a solid catalyst for preparing propylene carbonate and a preparation method of the solid catalyst. 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. The method comprises the following steps: (1) dipping a titanium silicalite molecular sieve in a solution containing an active component precursor and an optional metal oxide precursor, standing in a dark place, drying, optionally roasting, and then reducing to obtain a catalyst intermediate; and (2) loading a halogen-containing compound on the catalyst intermediate to obtain the solid catalyst. By adopting the solid catalyst disclosed 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 solid catalyst for preparing propylene carbonate and a preparation method thereof. Background Art

[0002] Propylene carbonate is an important cyclic organic carbonate product in the field of new energy. 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 to produce high-end chemical products such as dimethyl carbonate and propylene glycol. With the urgent demand for special electronic chemicals in my country's electric vehicle industry and the rapid development of the biodegradable materials industry, the new output value of propylene carbonate and its derivatives will reach nearly 100 billion yuan in the next five years.

[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 2The 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 purpose of the present invention is to provide a solid catalyst for preparing propylene carbonate and a preparation method thereof. The solid catalyst of the present invention can make 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; one-step direct synthesis, the entire process process conditions are the same, avoiding the process condition switching problem caused by different two-step process conditions; and the solid catalyst 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 first aspect of the present invention provides a solid catalyst for preparing propylene carbonate, the solid catalyst comprising a titanium silicalite and an active component and a halogen-containing compound supported on the titanium silicalite, wherein the active component is gold.

[0010] Preferably, 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.

[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, 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] The second aspect of the present invention provides a method for preparing the above-mentioned solid catalyst, the method comprising:

[0017] (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 it, optionally calcining it, and then reducing it to obtain a catalyst intermediate;

[0018] (2) Loading a halogen-containing compound on the catalyst intermediate to obtain the solid catalyst.

[0019] Preferably, the titanium silicate molecular sieve is TS-1 titanium silicate molecular sieve.

[0020] Preferably, the active component precursor is at least one of chloroauric acid, gold chloride and gold acetate.

[0021] Preferably, the metal oxide precursor is at least one of zinc nitrate, zinc chloride, zinc bromide, magnesium nitrate, magnesium chloride and magnesium bromide.

[0022] Preferably, when the halogen-containing compound is butylammonium bromide and / or propylammonium bromide, the process of loading the halogen-containing compound on the catalyst intermediate comprises: reacting the catalyst intermediate, 3-(aminopropyl)triethoxysilane and n-butyl bromide and / or n-propyl bromide under reflux conditions in the presence of an organic solvent, and collecting, washing and drying the solid after the reaction is completed.

[0023] Preferably, when the halogen-containing compound is ZnBr 2 When at least one of KBr and KI is present, the process of loading the halogen-containing compound on the catalyst intermediate comprises: placing the catalyst intermediate in an aqueous solution of the halogen-containing compound, stirring, filtering, washing and drying.

[0024] According to the technical solution of the present invention, the solid catalyst of the present invention can be used to make propylene, H 2 , O 2 With CO 2 Propylene carbonate is directly and continuously synthesized through a one-step reaction, and the selectivity of propylene carbonate is high; moreover, propylene carbonate can be directly synthesized in one reactor by using the solid catalyst of the present invention, while the prior art generally requires two-step reactions, and the two-step reactions use different catalysts and different reaction conditions, and need to switch between different reaction conditions; furthermore, compared with the traditional two-step method for synthesizing propylene carbonate, the solid catalyst of the present invention for synthesizing propylene carbonate significantly simplifies the process, eliminates the steps of separation and purification of propylene oxide and storage and transportation, significantly reduces process energy consumption, and improves the economy of the whole process; in addition, the solid catalyst of the present invention is easy to separate and reuse, and the overall cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic diagram of a system for preparing propylene carbonate.

[0026] Description of Reference Numerals

[0027] 1. Gas mixing unit; 2. Fixed bed reactor; 3. Gas-liquid separation unit; 4. Raw gas circulation unit. DETAILED DESCRIPTION

[0028] 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.

[0029] 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.

[0030] The solid catalyst for preparing propylene carbonate of the present invention comprises titanium silicon molecular sieve and active components and halogen-containing compounds loaded on the titanium silicon molecular sieve, wherein the active component is gold.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] In the present invention, the metal oxide is preferably zinc oxide and / or magnesium oxide.

[0038] The present invention also provides a method for preparing the solid catalyst, which comprises:

[0039] (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 it, optionally calcining it, and then reducing it to obtain a catalyst intermediate;

[0040] (2) Loading a halogen-containing compound on the catalyst intermediate to obtain the solid catalyst.

[0041] In the method of 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.

[0042] In the method of the present invention, the active component precursor is a water-soluble metal compound for providing a gold component. In a preferred embodiment, the active component precursor is at least one of chloroauric acid, gold chloride and gold acetate.

[0043] In the method of the present invention, the metal oxide precursor may be at least one of zinc nitrate, zinc chloride, zinc bromide, magnesium nitrate, magnesium chloride and magnesium bromide.

[0044] In the method described in the present invention, in step (1), the process of standing in the dark is carried out at room temperature, and the time of standing in the dark can be 5-48 hours.

[0045] In the method of the present invention, in step (1), the drying temperature can be 60-100°C.

[0046] In the method of the present invention, in step (1), when the prepared solid catalyst does not contain metal oxide, no metal oxide precursor is added in step (1), and no calcination operation is performed after drying; when the prepared solid catalyst contains metal oxide, a metal oxide precursor is added in step (1), and calcination operation is required after drying. In the case where calcination operation is required, the calcination conditions may include: temperature of 350-450°C and time of 1-10h.

[0047] In the method of the present invention, in step (1), the reduction is carried out in an atmosphere containing hydrogen. The hydrogen-containing atmosphere can be a hydrogen-nitrogen mixed gas, and the content of hydrogen in the hydrogen-nitrogen mixed gas is 5 volume % or more, preferably 8-20 volume %. The reduction conditions may include: a temperature of 250-350° C. and a time of 1-10 hours.

[0048] In the method of the present invention, in the solid catalyst finally prepared, the halogen-containing compound can be butylammonium bromide, propylammonium bromide, ZnBr 2 , KBr and KI.

[0049] In some embodiments, when the halogen-containing compound is butylammonium bromide and / or propylammonium bromide, the process of loading the halogen-containing compound on the catalyst intermediate in step (2) includes: reacting the catalyst intermediate, 3-(aminopropyl)triethoxysilane and n-butyl bromide and / or n-propyl bromide under reflux conditions in the presence of an organic solvent, and collecting, washing and drying the solid after the reaction is completed.

[0050] In other embodiments, when the halogen-containing compound is ZnBr 2 When at least one of KBr and KI is present, the process of loading the halogen-containing compound on the catalyst intermediate in step (2) comprises: placing the catalyst intermediate in an aqueous solution of the halogen-containing compound, stirring, filtering, washing and drying.

[0051] In the method described in the present invention, the amounts of the titanium silicon molecular sieve, the active component precursor, the metal oxide precursor and the raw material for providing the halogen-containing compound are such that in the prepared 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 carrier; 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; the content of the metal oxide is 0.1-5 parts by weight, preferably 0.5-4 parts by weight.

[0052] The process of preparing propylene carbonate using the solid catalyst of the present invention can be carried out in Figure 1 The system shown is implemented in the embodiment, specifically, the system includes:

[0053] The raw gas supply unit is used to supply propylene and H 2 , O 2 and CO 2 ;

[0054] 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;

[0055] 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 is the solid catalyst described in the present invention;

[0056] A gas-liquid separation unit 3, used for performing gas-liquid separation on the reaction product of the fixed bed reactor;

[0057] 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.

[0058] In the system, 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.

[0059] In the system, the gas mixing unit 1 may be a gas static mixer.

[0060] In the system, 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.

[0061] In the system, 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.

[0062] In the system, 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.

[0063] Preferably, each device in the system is made of 316L stainless steel.

[0064] In a specific embodiment, the process for preparing propylene carbonate in the above system comprises:

[0065] 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 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);

[0066] Passing the mixed gas from the gas mixing unit 1 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 is the solid catalyst described in the present invention;

[0067] 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;

[0068] 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.

[0069] The solid catalyst for preparing propylene carbonate and the preparation method thereof according to the present invention are further illustrated by examples. The examples are implemented on the premise of the technical solution of the present invention, and detailed implementation methods and specific operation processes are given, but the protection scope of the present invention is not limited to the following examples.

[0070] 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.

[0071] Example 1

[0072] (1) Preparation of solid catalyst

[0073] 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.

[0074] 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.

[0075] (2) Synthesis of Propylene Carbonate

[0076] 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.

[0077] 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%.

[0078] Example 2

[0079] (1) Preparation of solid catalyst

[0080] 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.

[0081] (2) Synthesis of Propylene Carbonate

[0082] 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.

[0083] 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%.

[0084] Example 3

[0085] (1) Preparation of solid catalyst

[0086] 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.

[0087] (2) Synthesis of Propylene Carbonate

[0088] 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 / 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.

[0089] 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%.

[0090] Example 4

[0091] (1) Preparation of solid catalyst

[0092] 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.

[0093] (2) Synthesis of Propylene Carbonate

[0094] 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 / 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.

[0095] 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%.

[0096] Example 5

[0097] (1) Preparation of solid catalyst

[0098] 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.

[0099] 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.

[0100] (2) Synthesis of Propylene Carbonate

[0101] 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-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.

[0102] 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%.

[0103] Example 6

[0104] (1) Preparation of solid catalyst

[0105] The 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 amounts of raw materials were adjusted so that in the prepared solid catalyst Cat-6, based on 100 parts by weight of TS-1 titanium silicalite molecular sieve, the gold content was 3.4 parts by weight, the zinc oxide content was 0.8 parts by weight, and the content of butylammonium bromide in terms of bromine element was 1.3 parts by weight.

[0106] (2) Synthesis of propylene carbonate

[0107] This example was carried out in the Figure 1 system shown. Specifically, propylene, H 2 , O 2 and CO 2 were continuously introduced into the gas mixing unit in a certain ratio and mixed evenly. Among them, the molar ratio of propylene / H 2 / O 2 / CO 2 was 3 / 3 / 3 / 16, and the pressure of the gas mixing unit was 0.5 MPa; the mixed raw material gas was pressured into the downflow fixed-bed reactor filled with solid catalyst Cat-6 by self-pressure. The outlet pressure of the fixed-bed reactor was 0.1 MPa, the raw material space velocity was 4000 mL / (g cat ·h), and the reaction temperature was 200 °C; after the reaction product came out of the downflow fixed-bed reactor, it entered the gas-liquid separation tank for separation. The gas-phase components (unreacted propylene, H 2 , O 2 and CO 2 ) were sampled and analyzed, and the rest were pumped into the gas mixing unit for recycling. The liquid-phase components (crude propylene carbonate) were taken out from the bottom of the gas-liquid separation tank for analysis.

[0108] By quantitative analysis and calculation using gas chromatography (equipped with an HP-1 chromatographic column), it was found that the single-pass conversion rate of propylene was 9.5%, and the selectivity of propylene carbonate was 93.6%.

[0109] Example 7

[0110] (1) Preparation of solid catalyst

[0111] The solid catalyst was prepared according to the method of Example 5, except that n-propyl bromide was used instead of n-butyl bromide, and the amounts of raw materials were adjusted so that in the prepared solid catalyst Cat-7, based on 100 parts by weight of TS-1 titanium silicalite molecular sieve, the gold content was 1.7 parts by weight, the zinc oxide content was 1.2 parts by weight, and the content of propylammonium bromide in terms of bromine element was 2.6 parts by weight.

[0112] (2) Synthesis of propylene carbonate

[0113] This example was carried out in the Figure 1In 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.

[0114] 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%.

[0115] Example 8

[0116] (1) Preparation of solid catalyst

[0117] A solid catalyst was prepared according to the method of Example 5, except that the same molar amount of gold chloride was used instead of chloroauric acid, and the same molar amount of magnesium chloride was used instead of magnesium nitrate, to obtain a solid catalyst Cat-8.

[0118] (2) Synthesis of Propylene Carbonate

[0119] Propylene carbonate was synthesized according to the method of Example 5, except that the solid catalyst loaded in the fixed bed reactor was solid catalyst Cat-8.

[0120] 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 92.7%.

[0121] Example 9

[0122] (1) Preparation of solid catalyst

[0123] A solid catalyst was prepared according to the method of Example 5, except that the same molar amount of gold acetate was used instead of chloroauric acid, and the same molar amount of zinc bromide was used instead of magnesium nitrate, to obtain a solid catalyst Cat-9.

[0124] (2) Synthesis of Propylene Carbonate

[0125] Propylene carbonate was synthesized according to the method of Example 5, except that the solid catalyst loaded in the fixed bed reactor was solid catalyst Cat-9.

[0126] 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 91.8%.

[0127] Example 10

[0128] (1) Preparation of solid catalyst

[0129] The catalyst intermediate was prepared according to the method of Example 5.

[0130] 2.0 g of the catalyst intermediate was weighed and placed in 300 mL of 0.8 mol / L potassium bromide aqueous solution and stirred for 4 h. The mixture was filtered and washed three times, and then dried at 70 ° C for 12 h to obtain a solid catalyst Cat-10, wherein the inductively coupled plasma emission spectrometer and ion chromatography tests showed that, relative to 100 parts by weight of TS-1 titanium silicon molecular sieve, the gold content was 2.8 parts by weight, the magnesium oxide content was 0.6 parts by weight, and the potassium bromide content was 2.1 parts by weight in terms of bromine element.

[0131] (2) Synthesis of Propylene Carbonate

[0132] Propylene carbonate was synthesized according to the method of Example 5, except that the solid catalyst loaded in the fixed bed reactor was solid catalyst Cat-10.

[0133] Quantitative analysis and calculation by gas chromatography (equipped with HP-1 chromatographic column) revealed that the single-pass conversion of propylene was 7.8% and the selectivity of propylene carbonate was 89.4%.

[0134] Comparative Example 1

[0135] 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.

[0136] 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%.

[0137] Comparative Example 2

[0138] 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.

[0139] Quantitative analysis and calculation by gas chromatography (equipped with HP-1 chromatographic column) revealed that the single-pass conversion rate of propylene was 0%.

[0140] Comparative Example 3

[0141] 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.

[0142] 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%.

[0143] Comparative Example 4

[0144] 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.

[0145] 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%.

[0146] Comparative Example 5

[0147] 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.

[0148] 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%.

[0149] It can be seen from the results of the above examples and comparative examples that the solid catalyst of the present invention can be used to realize the continuous synthesis process 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.

[0150] 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 solid catalyst for preparing propylene carbonate, It is characterized in that 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 solid catalyst according to claim 1, It is characterized in that Relative to 100 parts by weight of the titanium silicalite 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 solid catalyst 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 solid catalyst 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. A solid catalyst according to any one of claims 1 to 4, It is characterized in that 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. A method for preparing the solid catalyst according to claim 1, It is characterized in that The method includes: (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 it, optionally calcining it, and then reducing it to obtain a catalyst intermediate; (2) Loading a halogen-containing compound on the catalyst intermediate to obtain the solid catalyst.

7. The method according to claim 6, It is characterized in that The titanium silicate molecular sieve is TS-1 titanium silicate molecular sieve.

8. The method according to claim 6, It is characterized in that The active component precursor is at least one of chloroauric acid, gold chloride and gold acetate.

9. The method according to claim 6, It is characterized in that The metal oxide precursor is at least one of zinc nitrate, zinc chloride, zinc bromide, magnesium nitrate, magnesium chloride and magnesium bromide.

10. The method according to any one of claims 6 to 9, It is characterized in that When the halogen-containing compound is butylammonium bromide and / or propylammonium bromide, the process of loading the halogen-containing compound on the catalyst intermediate comprises: reacting the catalyst intermediate, 3-(aminopropyl)triethoxysilane and n-butyl bromide and / or n-propyl bromide under reflux conditions in the presence of an organic solvent, and collecting, washing and drying the solid after the reaction is completed.

11. The method according to any one of claims 6 to 9, It is characterized in that When the halogen-containing compound is ZnBr 2 When at least one of KBr and KI is present, the process of loading the halogen-containing compound on the catalyst intermediate comprises: placing the catalyst intermediate in an aqueous solution of the halogen-containing compound, stirring, filtering, washing and drying.

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