CN108623539B - Process for preparing propylene oxide - Google Patents
Process for preparing propylene oxide Download PDFInfo
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- CN108623539B CN108623539B CN201710166720.9A CN201710166720A CN108623539B CN 108623539 B CN108623539 B CN 108623539B CN 201710166720 A CN201710166720 A CN 201710166720A CN 108623539 B CN108623539 B CN 108623539B
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D301/00—Preparation of oxiranes
- C07D301/02—Synthesis of the oxirane ring
- C07D301/03—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds
- C07D301/04—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds with air or molecular oxygen
- C07D301/08—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds with air or molecular oxygen in the gaseous phase
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J29/00—Catalysts comprising molecular sieves
- B01J29/89—Silicates, aluminosilicates or borosilicates of titanium, zirconium or hafnium
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D303/00—Compounds containing three-membered rings having one oxygen atom as the only ring hetero atom
- C07D303/02—Compounds containing oxirane rings
- C07D303/04—Compounds containing oxirane rings containing only hydrogen and carbon atoms in addition to the ring oxygen atoms
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts
Abstract
The present invention relates to a process for the preparation of propylene oxide, which process comprises: in a fixed bed reactor, in the presence of a solvent, enabling a mixed gas containing hydrogen and oxygen to contact propylene and a catalyst for reaction, wherein the mixed gas enters the reactor from the end part of the reactor, the propylene enters the reactor from the middle part of the reactor, and the catalyst is a titanium silicalite molecular sieve catalyst containing noble metal. The method can obviously improve the conversion rate of propylene, the effective utilization rate of hydrogen and the selectivity of propylene oxide.
Description
Technical Field
The present invention relates to a process for the preparation of propylene oxide.
Background
Propylene Oxide (PO) is a bulk chemical raw material, the second largest organic chemical product of propylene derivatives with the second yield to polypropylene. The PO is very active in chemical property and wide in application because of having an oxygen-containing three-membered ring with very large tension, is mainly used for producing polyether, propylene glycol, isopropanolamine, allyl alcohol, non-polyether polyol and the like, can further produce unsaturated polyester resin, polyurethane, surfactants (an oil field demulsifier, a pesticide emulsifier and a wetting agent) and the like, is widely applied to the industries of chemical industry, light industry, medicine, food, textile and the like, and has profound influence on the development of chemical industry and national economy. With the expansion of PO application and the continuous increase of the dosage of downstream products, particularly the prosperity of industries such as automobiles, buildings, home furnishing and the like, the demand of polyurethane and nonionic surfactants is greatly increased, and the market demand of PO is vigorous.
At present, the chlorohydrin method and the co-oxidation method are mainly adopted for industrially producing the propylene oxide, the production capacity of the chlorohydrin method and the co-oxidation method accounts for more than 99 percent of the total production capacity of the world, and the yield accounts for half of the total production capacity of the world. The chlorohydrin process is earlier applied to production, uses toxic chlorine, is seriously corroded, generates a large amount of chlorine-containing wastewater polluting the environment, does not meet the requirements of green chemistry and clean production, and is finally eliminated along with the increasing requirement of environmental protection. The co-oxidation method indirectly oxidizes propylene to PO mainly using ethylbenzene peroxide or tert-butyl hydroperoxide as an oxygen source. The co-oxidation method overcomes the defects of environmental pollution, equipment corrosion and the like of the chlorohydrin method, and is a production process which is relatively cleaner than the chlorohydrin method. However, the method coproduces a large amount of cheap byproducts such as styrene or tert-butyl alcohol, the market of the byproducts is difficult to digest, and economic factors become main reasons for restricting the development of the byproducts due to the long process and large scale of capital investment.
The hydrogen peroxide is used as an oxidant, and the titanium silicalite molecular sieve can catalyze propylene epoxidation reaction to synthesize PO with high conversion rate and selectivity, so that a new way for PO synthesis is opened up. The process is simple, high in product conversion rate, good in selectivity and free of environmental pollution, is a very competitive propylene oxide production process, meets the requirements of modern green chemistry and atomic economic development concepts, and is considered as a green new process for producing PO. But due to H2O2Are extremely unstable, decompose when exposed to heat, light, rough surfaces, heavy metals and other impurities, are corrosive, and require special safety measures in packaging, storage and transportation. Preparation H2O2The need for separate equipment and recycle systems, high capital costs, high on-site production costs, cost and safety issues, and the process has certain economic barriers to industrialization before more stringent environmental regulations are released.
H2And O2Can directly synthesize H2O2By means of H2And O2To synthesize H in situ2O2The problem of directly utilizing H in the preparation of PO by reoxidizing propylene2O2The high cost of PO production. Since Pt, Pd, Au, Ag, etc. are H2And O2Synthesis of H2O2There are many reports in the literature that the active component is supported on a titanium silicon material to generate H in situ2O2Is used for the research of propylene gas-phase epoxidation reaction,for example, US6867312B1 and US 6884898B1, Meiers R. et al (J.Catal., 1998, 176: 376-2Low effective utilization rate and the like.
Disclosure of Invention
The invention aims to provide a method for preparing propylene oxide, which can obviously improve the conversion rate of propylene, the effective utilization rate of hydrogen and the selectivity of propylene oxide.
In order to achieve the above object, the present invention provides a method for preparing propylene oxide, comprising: in a fixed bed reactor, in the presence of a solvent, enabling a mixed gas containing hydrogen and oxygen to contact propylene and a catalyst for reaction, wherein the mixed gas enters the reactor from the end part of the reactor, the propylene enters the reactor from the middle part of the reactor, and the catalyst is a titanium silicalite molecular sieve catalyst containing noble metal.
Optionally, the end of the reactor is the top end and/or the bottom end of the reactor.
Alternatively, the molar ratio of propylene, oxygen, and hydrogen is 1: (0.1-10): (0.1-10), wherein the mass ratio of the solvent to the catalyst is (20-1000): 1, the mass ratio of the propylene to the catalyst is (0.1-50): 1.
optionally, the titanium silicalite molecular sieve is at least one selected from the group consisting of an MFI-type titanium silicalite molecular sieve, an MEL-type titanium silicalite molecular sieve, a BEA-type titanium silicalite molecular sieve, an MWW-type titanium silicalite molecular sieve, an MOR-type titanium silicalite molecular sieve, a TUN-type titanium silicalite molecular sieve, and a hexagonal structure titanium silicalite molecular sieve.
Optionally, the noble metal is at least one selected from Ru, Rh, Pd, Re, Os, Ir, Pt, Ag, and Au.
Optionally, the step of preparing the noble metal-containing titanium silicalite molecular sieve comprises:
(1) mixing a first part of silicon source, an optional first part of titanium source and a first part of alkaline template agent in the presence of an aqueous solvent, and then carrying out first crystallization to obtain a first mixture;
(2) mixing the first mixture, a second part of silicon source, a second part of titanium source, an optional second part of alkaline template and optional water, and then carrying out second crystallization to obtain a second mixture, and then recovering a solid product;
wherein step (1) and/or step (2) is carried out in the presence of a noble metal source;
the molar ratio of the silicon source, the titanium source, the alkaline template agent and the water in the second mixture is 100: (0.5-5): (10-50): (500-: the mole ratio of the silicon source is (0.1-10): 100, the silicon source is SiO2The titanium source is calculated as TiO2The alkali source template is counted as N when containing nitrogen element, and the alkali source template is counted as OH when not containing nitrogen element-The noble metal source is calculated by a metal simple substance.
Optionally, the molar ratio of silicon source, basic templating agent, and water in the first mixture is 50: (10-50): (500-; preferably, the molar ratio of the silicon source, the titanium source, the basic template agent and the water in the first mixture is 50: (0.25-1): (10-50): (500-: 1, the silicon source is SiO2The titanium source is calculated as TiO2The alkali source template is counted as N when containing nitrogen element, and the alkali source template is counted as OH when not containing nitrogen element-And (6) counting.
Optionally, the conditions of the first crystallization include: the temperature is 80-220 ℃, and the time is 12-96 h; the conditions of the second crystallization include: the temperature is 140 ℃ and 180 ℃, and the time is 6-24 h.
Optionally, the first crystallization is sequentially subjected to a stage (1), a stage (2) and a stage (3), wherein the stage (1) is crystallized at 80-120 ℃ for 6-30 hours; the temperature of the stage (2) is raised to 180 ℃ and 220 ℃ for crystallization for 0.5 to 8 hours; the temperature of the stage (3) is reduced to 140 ℃ and 180 ℃ for crystallization for 6-48 hours.
Optionally, the temperature difference between stage (3) and stage (2) is at least 20 ℃, preferably 25-60 ℃; the temperature rising rate from the room temperature to the stage (1) is 0.1-20 ℃/min, the temperature rising rate from the stage (1) to the stage (2) is 1-50 ℃/min, and the temperature falling rate from the stage (2) to the stage (3) is 1-20 ℃/min.
Optionally, the basic template is at least one selected from urea, quaternary ammonium base compounds, aliphatic amine compounds and aliphatic alcohol amine compounds;
the silicon source is inorganic silicon source and/or organic silicon source, the inorganic silicon source is at least one selected from silicate, silica sol and silica gel, the organic silicon source is at least one selected from silicon-containing compound shown in formula I, in the formula I, R is1、R2、R3And R4Each is C1-C4The alkyl group of (a) is,
the titanium source is inorganic titanium salt and/or organic titanate;
the noble metal source is at least one selected from the group consisting of an oxide of a noble metal, a halide of a noble metal, a carbonate of a noble metal, a nitrate of a noble metal, an ammonium nitrate salt of a noble metal, an ammonium chloride salt of a noble metal, a hydroxide of a noble metal, and a complex of a noble metal.
Optionally, the step of preparing the noble metal-containing titanium silicalite molecular sieve further comprises: step (1) and/or step (2) is carried out in the presence of a vanadium compound, wherein the molar ratio of the vanadium compound to the silicon source is (0.1-10): 100, the vanadium compound is calculated as V, and the silicon source is calculated as SiO2Counting;
preferably, step (1) is carried out in the presence of the vanadium compound;
the vanadium compound is at least one selected from the group consisting of an oxide of vanadium, a halide of vanadium, vanadic acid, a vanadate, a carbonate of vanadium, a nitrate of vanadium, a sulfate of vanadium, and a hydroxide of vanadium.
Alternatively, the solvent is at least one selected from the group consisting of water, methanol, ethanol, n-propanol, isopropanol, tert-butanol, isobutanol, acetone, butanone, and acetonitrile.
Optionally, the method further comprises: the reaction is carried out in the presence of a diluent gas, the molar ratio of the diluent gas to propylene being (1-100): 1, the diluent gas is at least one selected from the group consisting of nitrogen, argon, helium, neon, carbon dioxide, methane, ethane, and propane.
Optionally, the molar ratio of hydrogen to oxygen in the mixed gas is (0.5-2): 1.
optionally, the method further comprises: in the presence of a solvent, the mixed gas enters the reactor from the end part of the reactor to contact with a catalyst for a first reaction to obtain a first reactant, and then the propylene enters the reactor from the middle part of the reactor to continue to contact with the first reactant and the catalyst for a second reaction.
Optionally, the conditions of the first reaction are: the temperature is 0-80 ℃, the pressure is 0.1-30MPa, and the total liquid hourly space velocity is 0.02-20h-1(ii) a The conditions of the second reaction are as follows: the temperature is 0-80 ℃, the pressure is 0.1-30MPa, and the total liquid hourly space velocity is 0.02-20h-1。
According to the technical scheme, the method for preparing the propylene oxide is carried out in the fixed bed reactor, the mixed gas containing the hydrogen and the oxygen is introduced into the reactor from the end part, so that the retention time of the mixed gas in a catalyst bed layer can be prolonged, the mixed gas containing the hydrogen and the oxygen firstly reacts in the absence of the propylene to generate peroxide, the propylene enters the reactor from the middle part of the reactor and then reacts with the generated peroxide, meanwhile, the mixed gas containing the hydrogen and the oxygen can continuously react in the presence of the propylene to generate the peroxide, the peroxide can react while generating, and further the conversion rate of the propylene, the effective utilization rate of the hydrogen and the selectivity of the propylene oxide can be improved. Compared with the traditional method, the method provided by the invention solves the problems of low conversion rate of propylene and low effective utilization rate of hydrogen in a propylene gas-phase epoxidation reaction system to a certain extent, the whole preparation process is environment-friendly, and a better technical means is provided for industrial application of propylene oxide preparation by propylene epoxidation in the presence of hydrogen and oxygen.
Additional features and advantages of the invention will be set forth in the detailed description which follows.
Detailed Description
The following describes in detail specific embodiments of the present invention. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.
The present invention provides a process for producing propylene oxide, which comprises: in a fixed bed reactor, in the presence of a solvent, enabling a mixed gas containing hydrogen and oxygen to contact propylene and a catalyst for reaction, wherein the mixed gas enters the reactor from the end part of the reactor, the propylene enters the reactor from the middle part of the reactor, and the catalyst is a titanium silicalite molecular sieve catalyst containing noble metal. The mixed gas containing hydrogen and oxygen is introduced into the reactor from the end part, so that the residence time of the mixed gas in the catalyst bed layer can be increased, the mixed gas firstly reacts to generate peroxide, propylene enters the reactor from the middle part of the reactor and then reacts with the generated peroxide, meanwhile, the mixed gas containing hydrogen and oxygen can continuously react to generate peroxide in the presence of propylene, at the moment, the peroxide can be generated and reacted at the same time, and the conversion rate of the propylene, the effective utilization rate of the hydrogen and the selectivity of the propylene oxide can be further improved.
According to the invention, the end of the reactor may be the top end and/or the bottom end of the reactor. As can be understood by those skilled in the art, the mixed gas is a mixed gas containing hydrogen and oxygen in a specific ratio, and the mixed gas entering the reactor from the end of the fixed bed reactor means that the hydrogen and the oxygen are mixed in a specific ratio and then are introduced from the top end or the bottom end of the fixed bed reactor, or the hydrogen and the oxygen can be mixed in a specific ratio and then are introduced from the two ends of the reactor simultaneously in two parts, as long as the mixed gas is introduced into the reactor from the end of the fixed bed reactor to achieve the purpose of prolonging the residence time of the mixed gas in the catalyst bed layer.
In order to achieve the desired reaction effect, the molar ratio of the propylene to the oxygen to the hydrogen may be 1: (0.1-10): (0.1-10), preferably 1: (0.2-5): (0.2-5); the mass ratio of the solvent to the catalyst may be (20-1000): 1, preferably (20-500): 1; the mass ratio of propylene to catalyst may be (0.1-50): 1.
according to the present invention, the titanium silicalite molecular sieve is a common titanium silicalite molecular sieve, for example, the titanium silicalite molecular sieve can be an MFI type titanium silicalite molecular sieve (such as TS-1 molecular sieve), an MEL type titanium silicalite molecular sieve (such as TS-2 molecular sieve), a BEA type titanium silicalite molecular sieve (such as Ti-beta molecular sieve), an MWW type titanium silicalite molecular sieve (such as Ti-MCM-22 molecular sieve), an MOR type titanium silicalite molecular sieve (such as Ti-MOR molecular sieve), a TUN type titanium silicalite molecular sieve (such as Ti-TUN molecular sieve), a hexagonal structure titanium silicalite molecular sieve (such as Ti-MCM-41 molecular sieve, Ti-SBA-15 molecular sieve), and other structure titanium silicalite molecular sieves (such as Ti-ZSM-48 molecular sieve), etc. Preferably, the titanium silicalite molecular sieve is at least one selected from the group consisting of an MFI-type titanium silicalite molecular sieve, an MEL-type titanium silicalite molecular sieve and a BEA-type titanium silicalite molecular sieve. Further preferably, the titanium silicalite molecular sieve is an MFI-type titanium silicalite molecular sieve. Most preferably, the titanium silicalite molecular sieve is a TS-1 titanium silicalite molecular sieve. The above titanium silicalite molecular sieves are commercially available or can be produced, and the methods for producing the titanium silicalite molecular sieves are well known to those skilled in the art, such as the methods described in Zeolite, 1992, Vol.12, page 943-950, and the present invention is not described herein in detail.
According to the present invention, the noble metal may be a noble metal selected from group VIIB, VIII and IB, preferably at least one selected from Ru, Rh, Pd, Re, Os, Ir, Pt, Ag and Au
The noble metal-containing titanium silicalite molecular sieve catalyst can be prepared by a conventional method in the field. According to a preferred embodiment of the present invention, the preparation of the noble metal-containing titanium silicalite molecular sieve comprises:
(1) mixing a first part of silicon source, an optional first part of titanium source and a first part of alkaline template agent in the presence of an aqueous solvent, and then carrying out first crystallization to obtain a first mixture;
(2) mixing the first mixture, a second part of silicon source, a second part of titanium source, an optional second part of alkaline template and optional water, and then carrying out second crystallization to obtain a second mixture, and then recovering a solid product;
wherein step (1) and/or step (2) is carried out in the presence of a noble metal source;
the molar ratio of the silicon source, the titanium source, the alkaline template agent and the water in the second mixture is 100: (0.5-5): (10-50): (500-: the mole ratio of the silicon source is (0.1-10): 100, the silicon source is SiO2The titanium source is calculated as TiO2The alkali source template is counted as N when containing nitrogen element, and the alkali source template is counted as OH when not containing nitrogen element-The noble metal source is calculated by a metal simple substance. The titanium silicalite molecular sieve containing noble metal prepared by the preparation steps has higher catalytic activity, and can further improve the conversion rate of propylene, the effective utilization rate of hydrogen and the selectivity of propylene oxide.
In the preparation steps of the titanium silicalite molecular sieve containing noble metal, no special requirement is required on the conditions of the first crystallization and the second crystallization, and the conventional crystallization conditions can be used in the invention, and the conditions of the first crystallization and the second crystallization can be the same or different.
According to the present invention, preferably, the conditions of the first crystallization include: the temperature is 80-220 ℃, the time is 12-96h, and the conditions of the second crystallization comprise: the temperature is 140 ℃ and 180 ℃, and the time is 6-24 h.
According to a preferred embodiment of the invention, the first crystallization is successively subjected to a stage (1), a stage (2) and a stage (3), the stage (1) being crystallized at 80-120 ℃; stage (2) heating to 180-220 ℃ for crystallization; the temperature of the stage (3) is reduced to 140 ℃ and 180 ℃ for crystallization.
According to a preferred embodiment of the invention, the temperature difference between stage (3) and stage (2) is at least 20 ℃, preferably between 25 and 60 ℃; the temperature rising rate from the room temperature to the stage (1) is 0.1-20 ℃/min, preferably 2-10 ℃/min; the temperature rising rate from the stage (1) to the stage (2) is 1-50 ℃/min, preferably 15-20 ℃/min; the cooling rate of the stage (2) to the stage (3) is 1-20 ℃/min, preferably 10-20 ℃/min.
According to a preferred embodiment of the invention, the crystallization time of stage (1) is between 6 and 30 hours, preferably between 20 and 30 hours; the crystallization time of the stage (2) is 0.5 to 8 hours, preferably 4 to 6 hours; the crystallization time of stage (3) is 6 to 48 hours, preferably 30 to 48 hours.
According to a preferred embodiment of the present invention, the molar ratio of the silicon source, the basic templating agent and the water in the first mixture may be 50: (10-50): (500-; preferably, the molar ratio of the silicon source, the titanium source, the basic template agent and the water in the first mixture is 50: (0.25-1): (10-50): (500-5000). The molar ratio of the first part of silicon source to the second part of silicon source is (1-10): 1. wherein the silicon source is SiO2The titanium source is calculated as TiO2The alkali source template is counted as N when containing nitrogen element, and the alkali source template is counted as OH when not containing nitrogen element-And (6) counting.
According to the method of the present invention, the aqueous solvent is substantially water, and a cosolvent may be added as needed.
In the present invention, the silicon source may be an inorganic silicon source and/or an organic silicon source, and the first silicon source and the second silicon source may be the same or different.
Specifically, the organic silicon source may be, for example, at least one selected from silicon-containing compounds represented by formula I,
in the formula I, R1、R2、R3And R4Each is C1-C4Alkyl of (2) including C1-C4Straight chain alkyl of (2) and C3-C4Branched alkyl groups of (a), for example: r1、R2、R3And R4Each may be methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl or tert-butyl.
Specifically, the organic silicon source may be at least one of tetramethyl orthosilicate, tetraethyl orthosilicate, tetra-n-propyl orthosilicate, and tetra-n-butyl orthosilicate. Tetraethyl orthosilicate or tetra-n-propyl orthosilicate are used as examples in the specific embodiments of the present invention, but do not limit the scope of the present invention accordingly.
According to the method of the present invention, the optional range of the types of the inorganic silicon source is wide, and for the present invention, the inorganic silicon source is preferably one or more of silicate, silica sol and silica gel, and the silica gel or silica sol in the present invention may be silica gel or silica sol obtained by various production methods in various forms, and the silicate is sodium silicate, for example.
In the present invention, the basic template may be an organic base source and/or an inorganic base source commonly used in the art. Preferably, the basic template agent is an organic base, and the organic base is one or more of urea, a quaternary ammonium base compound, an aliphatic amine compound and an aliphatic alcohol amine compound.
In the invention, the quaternary ammonium base can be various organic quaternary ammonium bases, and the aliphatic amine can be various NH3In which at least one hydrogen is substituted with an aliphatic hydrocarbon group (preferably an alkyl group), which may be a variety of NH3Wherein at least one hydrogen is substituted with a hydroxyl-containing aliphatic hydrocarbon group (preferably an alkyl group).
Specifically, the quaternary ammonium base may be a quaternary ammonium base represented by formula II, the aliphatic amine may be an aliphatic amine represented by formula III, and the aliphatic alcohol amine may be an aliphatic alcohol amine represented by formula IV:
in the formula II, R5、R6、R7And R8Each is C1-C4Alkyl of (2) including C1-C4Straight chain alkyl of (2) and C3-C4Branched alkyl groups of (a), for example: r5、R6、R7And R8Each may be methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl or tert-butyl.
R9(NH2)n(formula III)
In the formula III, n is an integer of 1 or 2. When n is 1, R9Is C1-C6Alkyl of (2) including C1-C6Straight chain alkyl of (2) and C3-C6Such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, neopentyl, isopentyl, tert-pentyl and n-hexyl. When n is 2, R9Is C1-C6Alkylene of (2) including C1-C6Linear alkylene of (A) and (C)3-C6Such as methylene, ethylene, n-propylene, n-butylene, n-pentylene or n-hexylene. More preferably, the aliphatic amine compound is one or more of ethylamine, n-butylamine, butanediamine and hexamethylenediamine
(HOR10)mNH(3-m)(formula IV)
In the formula IV, m are R10Are the same or different and are each C1-C4Alkylene of (2) including C1-C4Linear alkylene of (A) and (C)3-C4Branched alkylene groups of (a), such as methylene, ethylene, n-propylene and n-butylene; m is 1, 2 or 3. More preferably, the aliphatic alcohol amine compound is one or more of monoethanolamine, diethanolamine and triethanolamine.
In the invention, the titanium source can be an inorganic titanium source and/or an organic titanate. The inorganic titanium salt is selected from a variety of hydrolysable titanium salts, such as may be selected from TiX4、TiOX2Or Ti (SO)4)2And the like, wherein X is halogen, preferably chlorine, wherein preferably the inorganic titanium salt is selected from TiCl4、Ti(SO4)2And TiOCl2One or more of (a). The organic titanate is preferably of the formula M4TiO4Wherein M is preferably an alkyl group having 1 to 6 carbon atoms, preferably an alkyl group having 2 to 4 carbon atoms, and 4M may be the same or different, preferably the organotitanate is selected from one or more of isopropyl titanate, n-propyl titanate, tetrabutyl titanate and tetraethyl titanate, tetrabutyl titanate being used in a specific embodiment of the present invention, but not limiting the scope of the present invention accordingly.
According to a preferred embodiment of the present invention, it is preferred that the noble metal source is at least one selected from the group consisting of an oxide of a noble metal, a halide of a noble metal, a carbonate of a noble metal, a nitrate of a noble metal, an ammonium nitrate salt of a noble metal, an ammonium chloride salt of a noble metal, a hydroxide of a noble metal, and a complex of a noble metal, and the noble metal is at least one selected from the group consisting of Ru, Rh, Pd, Re, Os, Ir, Pt, Ag, and Au.
According to a preferred embodiment of the present invention, the step of preparing the noble metal-containing titanium silicalite molecular sieve further comprises: step (1) and/or step (2) is carried out in the presence of a vanadium compound, the molar ratio of the vanadium compound to the silicon source being (0.1-10): 100, the vanadium compound is calculated as V, and the silicon source is calculated as SiO2Counting; more preferably, step (1) is carried out in the presence of a vanadium compound.
According to a preferred embodiment of the present invention, preferably said vanadium compound is selected from the group consisting of oxides of vanadium, halides of vanadium, vanadic acid (HVO)3) Orthovanadic acid (H)3VO4) Pyrovanadic acid (H)4V2O7、H3V3O9) Vanadate (corresponding salts of the aforementioned vanadic acid), carbonate of vanadium, nitrate of vanadium, sulfate of vanadium, and hydroxide of vanadium, including but not limited to sodium vanadate, ammonium metavanadate, vanadium pentoxide, vanadium oxytrichloride, potassium metavanadate, vanadyl sulfate, vanadium acetylacetonate, and the like.
In the method for preparing propylene oxide provided by the present invention, the solvent may be at least one selected from water, alcohols, ketones, and nitriles. The alcohol may be at least one selected from the group consisting of methanol, ethanol, n-propanol, isopropanol, tert-butanol and isobutanol, the ketone may be acetone and/or butanone, and the nitrile may be acetonitrile. Preferably, the solvent is methanol and/or water.
In order to further improve the conversion rate of the propylene, the effective utilization rate of the hydrogen and the selectivity of the propylene oxide, the method can further comprise the following steps: the reaction is carried out in the presence of a diluent gas, the molar ratio of the diluent gas to propylene being (1-100): 1, the diluent gas may be at least one selected from the group consisting of nitrogen, argon, helium, neon, carbon dioxide, methane, ethane, and propane.
In order to achieve the desired reaction effect, the molar ratio of hydrogen to oxygen in the mixed gas may be (0.5-2): 1, most preferably 1: 1.
in order to further improve the conversion rate of the propylene, the effective utilization rate of the hydrogen and the selectivity of the propylene oxide, the method can further comprise the following steps: in the presence of a solvent, the mixed gas enters the reactor from the end part of the reactor to contact with a catalyst for a first reaction to obtain a first reactant, and then the propylene enters the reactor from the middle part of the reactor to continue to contact with the first reactant and the catalyst for a second reaction. The mixed gas containing hydrogen and oxygen is firstly led into the reactor from the end part to carry out a first reaction for a period of time, so that the residence time of the mixed gas in the catalyst bed layer can be further increased, the mixed gas firstly reacts to generate peroxide, and after a period of time, propylene enters the reactor from the middle part of the reactor to carry out a second reaction with the generated peroxide, so that the conversion rate of the propylene, the effective utilization rate of the hydrogen and the selectivity of the propylene oxide can be further improved.
In the method for preparing propylene oxide provided by the invention, the reaction conditions can be as follows: the temperature is 0-80 ℃, the pressure is 0.1-30MPa, and the total liquid hourly space velocity can be 0.02-20h-1. When the above preferred embodiment is employed, the reaction temperature and pressure before and after the propylene is fed into the reaction system may be the same or different, and preferably, the conditions of the first reaction are: the temperature is 0-80 ℃, and the preferable temperature is 0-60 ℃; the pressure is 0.1-30MPa, and more preferably 0.3-20 MPa; the total liquid hourly space velocity is 0.02-20h-1More preferably 0.1 to 10 hours-1(ii) a The conditions of the second reaction are as follows: the temperature is 0-80 ℃, and the preferable temperature is 0-60 ℃; the pressure is 0.1-30MPa, and more preferably 0.3-20 MPa; the total liquid hourly space velocity is 0.02-20h-1More preferably 0.1 to 10 hours-1。
The invention will now be further illustrated by the following examples, without thereby being limited thereto.
The composition of the reaction product is analyzed by on-line gas chromatography, and the analysis result is quantified by a correction normalization method. Wherein, the chromatographic analysis conditions are as follows: agilent-6890 type chromatograph, PLOT/Q capillary chromatographic column, sample amount of 250 μ L, and sample inlet temperature of 280 deg.C. The column temperature was maintained at 40 ℃ for 2min, then ramped up to 200 ℃ at a rate of 15 ℃/min and maintained for 5 min. TCD detector, detector temperature 300 ℃.
In each of the examples and comparative examples:
propylene conversion (%) — the molar amount of propylene in the charge-the molar amount of unreacted propylene)/the molar amount of propylene in the charge × 100%;
effective hydrogen utilization ratio (%) ═ molar amount of propylene oxide and its derivatives/molar amount of total hydrogen consumed by the reaction × 100%;
propylene oxide selectivity (%) -, mol of propylene oxide in the product/mol of propylene total converted × 100%.
Example 1
The catalyst used in this example is a 1% Pd/TS-1 titanium silicalite catalyst, the pre-catalyst percentage represents the mass percentage of palladium, and the preparation method is as follows:
taking 10 g of titanium silicalite TS-1 (prepared by the method described in Zeolite, 1992, Vol.12, pages 943-950 in the prior art) and 15mL of water, adding 10mL of PdCl with the concentration of 0.01g/mL2Stirring the mixture in an aqueous solution at the temperature of 40 ℃ for 24 hours, sealing the mixture properly, and naturally drying the mixture at room temperature for 48 hours to obtain the catalyst (the catalyst needs to be subjected to reduction activation for 3 hours at the temperature of 300 ℃ in a nitrogen-hydrogen mixed atmosphere before the reaction for preparing the propylene oxide) for preparing the supported palladium/titanium silicalite (1% Pd/TS-1) catalyst by using the traditional titanium silicalite (TS-1) supported palladium.
In a fixed bed reactor, the catalyst is adopted, in the presence of a solvent methanol, mixed gas containing hydrogen and oxygen is introduced from the top end of the reactor, and propylene is introduced into the reactor from the middle part of the reactor for reaction. The molar ratio of propylene, oxygen and hydrogen is 1: 5: 5, the mass ratio of the methanol to the catalyst is 100: 1, the mass ratio of propylene to the catalyst is 4: 1. the total liquid hourly space velocity is 0.5h-1At a temperature of 40 deg.CThe reaction was carried out under a pressure of 2.0MPa for 2 hours, and the results of the analysis are shown in Table 1.
Example 2
The catalyst used in this example is a 1% Pd/TS-1 titanium silicalite catalyst, the pre-catalyst percentage represents the mass percentage of palladium, and the preparation method is as follows:
(1) adding 20 g of tetra-n-propyl orthosilicate serving as a first silicon source and palladium chloride serving as a noble metal source into n-butylamine aqueous solution serving as an alkaline template agent, uniformly stirring and mixing, placing the mixture into a stainless steel sealed reaction kettle, raising the temperature of the kettle to 80 ℃ from room temperature at a heating rate of 10 ℃/min, crystallizing for 30 hours at the temperature, raising the temperature of the kettle to 180 ℃ at a heating rate of 20 ℃/min, and crystallizing for 4 hours at the temperature; and then reducing the temperature of the kettle to 140 ℃ at a cooling rate of 10 ℃/min and crystallizing for 30 hours at the temperature to obtain a first mixture, wherein the molar ratio of the silicon source, the alkaline template and the water in the first mixture is 50: 35: 3000A;
(2) uniformly mixing the first mixture, a second part of silicon source tetraethyl orthosilicate and tetrabutyl titanate, and then carrying out second crystallization (at the temperature of 160 ℃ for 18 hours) to obtain a second mixture; the molar ratio of the first portion of silicon source to the second portion of silicon source is 1, the silicon source in the second mixture: noble metal sources: a titanium source: alkaline template agent: the molar ratio of the used water is 100: 1: 3: 35: 3000, finally, cooling to room temperature and depressurizing, filtering, washing, drying and roasting the product in the reaction kettle at 550 ℃ for 5 hours to obtain the supported palladium/titanium silicalite molecular sieve (1% Pd/TS-1) catalyst prepared by the preparation embodiment (reduction activation is needed in nitrogen and hydrogen mixed atmosphere at 300 ℃ for 3 hours before the reaction for preparing propylene oxide).
In a fixed bed reactor, the catalyst is adopted, in the presence of a solvent methanol, mixed gas containing hydrogen and oxygen is introduced from the top end of the reactor, and propylene is introduced into the reactor from the middle part of the reactor for reaction. The molar ratio of propylene, oxygen and hydrogen is 1: 5: 5, the mass ratio of the methanol to the catalyst is 100: 1, the mass ratio of propylene to the catalyst is 4: 1. the total liquid hourly space velocity is 0.5h-1At a temperature of 40 ℃ and a pressure of 2The reaction was carried out at 0MPa for 2 hours and the sample was analyzed, the results of which are shown in Table 1.
Example 3
Propylene oxide was prepared in the same manner as in example 2, except that in the preparation of the 1.0% Pd/TS-1 titanium silicalite catalyst used in this example, a vanadium compound was introduced in step (1), as follows;
adding 20 g of a first part of silicon source tetra-n-propyl orthosilicate, a noble metal source palladium chloride and ammonium metavanadate into an n-butylamine aqueous solution, stirring and mixing uniformly, placing the mixture into a stainless steel sealed reaction kettle for first crystallization, raising the kettle temperature to 80 ℃ at a heating rate of 10 ℃/min from room temperature, crystallizing for 30 hours at the temperature, raising the kettle temperature to 180 ℃ at a heating rate of 20 ℃/min, and crystallizing for 4 hours at the temperature; and then reducing the temperature of the kettle to 140 ℃ at a cooling rate of 10 ℃/min and crystallizing for 30 hours at the temperature to obtain a first mixture, wherein the molar ratio of the silicon source, the vanadium compound, the alkaline template and the water in the first mixture is 50: 2: 35: 3000A; the remaining steps and conditions were the same as in example 2.
The reaction results are listed in table 1.
Example 4
Propylene oxide was prepared in the same manner as in example 2, except that in the 1.0% Pd/TS-1 titanium silicalite catalyst used in this example, the first portion of the titanium source was introduced in step (1), as follows;
adding 20 g of a first part of silicon source tetra-n-propyl orthosilicate, a noble metal source palladium chloride and a first part of titanium source tetrabutyl titanate into n-butylamine aqueous solution, stirring and mixing uniformly, placing the mixture into a stainless steel sealed reaction kettle for first crystallization, raising the kettle temperature to 80 ℃ from room temperature at a heating rate of 10 ℃/min, crystallizing at the temperature for 30 hours, raising the kettle temperature to 180 ℃ at a heating rate of 20 ℃/min, and crystallizing at the temperature for 4 hours; and then reducing the temperature of the kettle to 140 ℃ at a cooling rate of 10 ℃/min, and crystallizing for 30 hours at the temperature to obtain a first mixture, wherein the molar ratio of a silicon source, a titanium source, an alkaline template and water in the first mixture is 50: 1: 35: 3000A; the remaining steps and conditions were the same as in example 2.
The reaction results are listed in table 1.
Example 5
Propylene oxide was prepared in the same manner as in example 2, except that in the 1.0% Pd/TS-1 titanium silicalite catalyst used in this example, a noble metal source was added in step (2), as follows;
(1) adding 20 g of tetra-n-propyl orthosilicate, a first part of which is a silicon source, into an n-butylamine aqueous solution, a basic template, stirring and mixing uniformly, placing the mixture into a stainless steel sealed reaction kettle, raising the temperature of the kettle to 80 ℃ from room temperature at a heating rate of 10 ℃/min, crystallizing for 30 hours at the temperature, raising the temperature of the kettle to 180 ℃ at a heating rate of 20 ℃/min, and crystallizing for 4 hours at the temperature; and then reducing the temperature of the kettle to 140 ℃ at a cooling rate of 10 ℃/min and crystallizing for 30 hours at the temperature to obtain a first mixture, wherein the molar ratio of the silicon source, the alkaline template and the water in the first mixture is 50: 35: 3000A;
(2) uniformly mixing the first mixture, a noble metal source palladium chloride, a second part of silicon source tetraethyl orthosilicate and tetrabutyl titanate, and then carrying out second crystallization (at the temperature of 160 ℃ for 18 hours) to obtain a second mixture; the molar ratio of the first portion of silicon source to the second portion of silicon source is 1, the silicon source in the second mixture: noble metal sources: a titanium source: alkaline template agent: the molar ratio of the used water is 100: 1: 3: 35: 3000, finally, cooling to room temperature and depressurizing, filtering, washing, drying and roasting the product in the reaction kettle at 550 ℃ for 5 hours to obtain the supported palladium/titanium silicalite molecular sieve (1% Pd/TS-1) catalyst prepared by the preparation embodiment (reduction activation is needed in nitrogen and hydrogen mixed atmosphere at 300 ℃ for 3 hours before the reaction for preparing propylene oxide).
The reaction results are listed in table 1.
Example 6
In a fixed bed reactor, the same 1% Pd/TS-1 titanium silicalite molecular sieve catalyst as in example 2 is adopted, in the presence of a solvent methanol, a mixed gas containing hydrogen and oxygen is introduced from the top end of the reactor, and propylene is introduced into the reactor from the middle part of the reactor for reaction. Propylene, oxygenThe molar ratio of gas to hydrogen is 1: 1: 1, the mass ratio of methanol to the catalyst is 60: 1, the mass ratio of propylene to the catalyst is 25: 1. the total liquid hourly space velocity is 2h-1The reaction was carried out at 40 ℃ and 2.0MPa for 2 hours, and the samples were taken and analyzed, and the results are shown in Table 1.
Example 7
In a fixed bed reactor, the same 1% Pd/TS-1 titanium silicalite molecular sieve catalyst as in example 2 is adopted, in the presence of a solvent methanol, a mixed gas containing hydrogen and oxygen is introduced from the top end of the reactor, and propylene is introduced into the reactor from the middle part of the reactor for reaction. The molar ratio of propylene, oxygen and hydrogen is 1: 2: 2, the mass ratio of the methanol to the catalyst is 200: 1, the mass ratio of propylene to the catalyst is 10: 1. the total liquid hourly space velocity is 1h-1The reaction was carried out at 40 ℃ and 2.0MPa for 2 hours, and the samples were taken and analyzed, and the results are shown in Table 1.
Example 8
In a fixed bed reactor, the same 1% Pd/TS-1 titanium silicalite molecular sieve catalyst as in example 2 is adopted, in the presence of solvent ethanol, mixed gas containing hydrogen and oxygen is introduced from the top of the reactor, and propylene is introduced into the reactor from the middle of the reactor for reaction. The molar ratio of propylene, oxygen and hydrogen is 1: 0.15: 0.1, the mass ratio of the ethanol to the catalyst is 600: 1, the mass ratio of propylene to the catalyst is 50: 1. the total liquid hourly space velocity is 0.05h-1The reaction was carried out at 70 ℃ and 0.2MPa for 2 hours, and the samples were taken and analyzed, the results of which are shown in Table 1.
Example 9
In a fixed bed reactor, the same 1% Pd/TS-1 titanium silicalite molecular sieve catalyst as in example 2 is adopted, in the presence of solvent acetone, mixed gas containing hydrogen and oxygen is introduced from the top of the reactor, and propylene is introduced into the reactor from the middle of the reactor for reaction. The molar ratio of propylene, oxygen and hydrogen is 1: 8: 10, the mass ratio of the acetone to the catalyst is 1000: 1, the mass ratio of propylene to the catalyst is 0.1: 1. the total liquid hourly space velocity is 1h-1The reaction was carried out at 40 ℃ and 2.0MPa for 2 hours, and the samples were taken and analyzed, and the results are shown in Table 1.
Example 10
In a fixed bed reactor, the same 1% Pd/TS-1 titanium silicalite molecular sieve catalyst as in example 2 is adopted, in the presence of a solvent methanol, a mixed gas containing hydrogen and oxygen is firstly introduced from the top end of the reactor, a first reaction is carried out under the conditions of the temperature of 40 ℃ and the pressure of 2.0MPa, and after 1 hour, propylene is introduced into the reactor from the middle part of the reactor, and a second reaction is continuously carried out under the conditions of the temperature of 40 ℃ and the pressure of 2.0 MPa. The molar ratio of propylene, oxygen and hydrogen is 1: 5: 5, the mass ratio of the methanol to the catalyst is 100: 1, the mass ratio of propylene to the catalyst is 4: 1, total liquid hourly space velocity of 0.5h-1After the second reaction was carried out for 1 hour, a sample was taken and analyzed, and the analysis results are shown in Table 1.
Example 11
In a fixed bed reactor, the same 1% Pd/TS-1 titanium silicalite molecular sieve catalyst as in example 2 is adopted, in the presence of a solvent methanol, a mixed gas containing hydrogen and oxygen is firstly introduced from the top end of the reactor, a first reaction is carried out under the conditions of the temperature of 60 ℃ and the pressure of 5.0MPa, propylene is introduced into the reactor from the middle part of the reactor after 0.2 hour, the temperature is adjusted to 25 ℃, and a second reaction is carried out under the condition of the pressure of 5.0 MPa. The molar ratio of propylene, oxygen and hydrogen is 1: 2: 3, the mass ratio of the methanol to the catalyst is 300: 1, the mass ratio of propylene to the catalyst is 0.5: 1, total liquid hourly space velocity of 0.5h-1After the second reaction was carried out for 2 hours, a sample was taken and analyzed, and the analysis results are shown in Table 1.
Example 12
In a fixed bed reactor, the same 1% Pd/TS-1 titanium silicalite molecular sieve catalyst as in example 2 is adopted, in the presence of a mixed solvent of water and methanol, a mixed gas containing hydrogen and oxygen is firstly introduced from the top end of the reactor, a first reaction is carried out under the conditions of the temperature of 30 ℃ and the pressure of 5.0MPa, and propylene is introduced into the reactor from the middle part of the reactor after 2 hours to continuously carry out a second reaction under the conditions of the temperature of 30 ℃ and the pressure of 5.0 MPa. Water in the mixed solvent: the mass ratio of methanol is 1: and 6, the molar ratio of the propylene to the oxygen to the hydrogen is 1: 0.2: 0.4, the mass ratio of the acetone to the catalyst is 70: 1, propylene and catalystThe mass ratio of (A) to (B) is 2: 1, total liquid hourly space velocity of 0.5h-1And after the second reaction is carried out for 0.5h, a sample is taken for analysis, and the analysis results are shown in Table 1.
Example 13
In a fixed bed reactor, the same 1% Pd/TS-1 titanium silicalite molecular sieve catalyst as in example 2 is adopted, in the presence of a solvent methanol, mixed gas containing hydrogen and oxygen is introduced from the top end of the reactor, diluent gas nitrogen is introduced from the top end of the reactor, and propylene is introduced into the reactor from the middle part of the reactor for reaction. The molar ratio of propylene, oxygen, hydrogen and diluent gas is 1: 5: 5: 10, the mass ratio of the methanol to the catalyst is 100: 1, the mass ratio of propylene to the catalyst is 4: 1. the total liquid hourly space velocity is 0.5h-1The reaction was carried out at 40 ℃ and 2.0MPa for 2 hours, and the samples were taken and analyzed, and the results are shown in Table 1.
Example 14
Propylene oxide was prepared by the same method as in example 2, except that the catalyst used in this example was a 3% Rh/TS-1 titanium silicalite catalyst, the pre-catalyst percentage represents the mass percent of rhodium, and the preparation method was as follows:
(1) adding 20 g of a first part of silicon source tetraethyl orthosilicate and noble metal source rhodium nitrate into an alkaline template n-butylamine aqueous solution, uniformly stirring and mixing, placing the mixture into a stainless steel sealed reaction kettle, raising the kettle temperature to 100 ℃ at a heating rate of 5 ℃/min from room temperature, crystallizing for 20 hours at the temperature, raising the kettle temperature to 200 ℃ at a heating rate of 15 ℃/min, and crystallizing for 6 hours at the temperature; and then reducing the temperature of the kettle to 160 ℃ at a cooling rate of 15 ℃/min and crystallizing for 40 hours at the temperature to obtain a first mixture, wherein the molar ratio of the silicon source to the alkaline template to the water in the first mixture is 50: 50: 4500;
(2) uniformly mixing the first mixture, a second part of silicon source tetraethyl orthosilicate and tetrabutyl titanate, and then carrying out second crystallization (the temperature is 180 ℃, and the time is 12 hours) to obtain a second mixture; the molar ratio of the first portion of silicon source to the second portion of silicon source is 1, the silicon source in the second mixture: noble metal sources: a titanium source: alkaline template agent: the molar ratio of the used water is 100: 3: 5: 50: 4500, cooling to room temperature and releasing pressure, filtering, washing, drying and roasting the product in the reaction kettle at 550 ℃ for 5 hours to obtain the supported rhodium/titanium silicalite molecular sieve (3% Rh/TS-1) catalyst (which needs to be subjected to reduction activation for 3 hours at 300 ℃ in a nitrogen-hydrogen mixed atmosphere before the reaction for preparing propylene oxide).
The reaction results are listed in table 1.
Example 15
Propylene oxide was prepared by the same method as in example 2, except that the catalyst used in this example was a 5% Ru/TS-1 titanium silicalite catalyst, the pre-catalyst percentage represents the mass percent of ruthenium, and the preparation method was as follows:
(1) adding 20 g of a first part of silicon source tetra-n-propyl orthosilicate, noble metal source rhodium oxide, ammonium metavanadate and a first part of titanium source tetrabutyl titanate into an alkaline template n-butylamine aqueous solution, uniformly stirring and mixing, placing the mixture into a stainless steel sealed reaction kettle, raising the temperature of the kettle to 120 ℃ from room temperature at a heating rate of 5 ℃/min, crystallizing for 25 hours at the temperature, raising the temperature of the kettle to 220 ℃ at a heating rate of 15 ℃/min, and crystallizing for 8 hours at the temperature; and then reducing the temperature of the kettle to 180 ℃ at a cooling rate of 20 ℃/min and crystallizing for 48 hours at the temperature to obtain a first mixture, wherein the molar ratio of a silicon source, a titanium source, a vanadium compound, an alkaline template and water in the first mixture is 50: 0.5: 5: 20: 1000, parts by weight;
(2) uniformly mixing the first mixture, a second part of silicon source tetra-n-propyl orthosilicate and a second part of tetrabutyl titanate, and then carrying out second crystallization (at the temperature of 140 ℃ for 10 hours) to obtain a second mixture; the molar ratio of the first portion of silicon source to the second portion of silicon source is 1, the silicon source in the second mixture: noble metal sources: a titanium source: alkaline template agent: the molar ratio of the used water is 100: 5: 1: 20: 1000, finally, cooling to room temperature and releasing pressure, filtering, washing, drying and roasting the product in the reaction kettle at 550 ℃ for 5 hours to obtain the supported ruthenium/titanium silicalite molecular sieve (5% Ru/TS-1) catalyst (which needs to be subjected to reduction activation for 3 hours at 300 ℃ in a nitrogen-hydrogen mixed atmosphere before the reaction for preparing the propylene oxide) prepared by the preparation embodiment.
The reaction results are listed in table 1.
Example 16
Propylene oxide was prepared in the same manner as in example 2, except that the catalyst used in this example was a 10% Pt/TS-1 titanium silicalite catalyst, the pre-catalyst percentage represents the mass percent of platinum, and the preparation method was as follows:
(1) adding 20 g of tetra-n-propyl orthosilicate serving as a first silicon source and platinum hydroxide serving as a noble metal source into n-butylamine aqueous solution serving as an alkaline template agent, uniformly stirring and mixing, placing the mixture into a stainless steel sealed reaction kettle, raising the temperature of the kettle to 100 ℃ from room temperature at a heating rate of 15 ℃/min, crystallizing at the temperature for 6 hours, raising the temperature of the kettle to 190 ℃ at a heating rate of 10 ℃/min, and crystallizing at the temperature for 8 hours; and then reducing the temperature of the kettle to 180 ℃ at a cooling rate of 5 ℃/min and crystallizing for 15 hours at the temperature to obtain a first mixture, wherein the molar ratio of the silicon source to the alkaline template to the water in the first mixture is 50: 10: 500, a step of;
(2) uniformly mixing the first mixture, a second part of silicon source tetraethyl orthosilicate and tetrabutyl titanate, and then carrying out second crystallization (the temperature is 180 ℃, and the time is 12 hours) to obtain a second mixture; the molar ratio of the first portion of silicon source to the second portion of silicon source is 1, the silicon source in the second mixture: noble metal sources: a titanium source: alkaline template agent: the molar ratio of the used water is 100: 10: 0.5: 10: and 500, finally, cooling to room temperature and relieving pressure, filtering, washing, drying and roasting the product in the reaction kettle at 550 ℃ for 5 hours to obtain the supported platinum/titanium silicalite molecular sieve (10% Pt/TS-1) catalyst (which needs to be subjected to reduction activation for 3 hours at 300 ℃ in a nitrogen-hydrogen mixed atmosphere before the reaction for preparing the propylene oxide) prepared by the preparation embodiment.
The reaction results are listed in table 1.
Example 17
Propylene oxide was prepared in the same manner as in example 16, except that in the preparation method using the 10% Pt/TS-1 titanium silicalite catalyst of this example, the first crystallization was not subjected to stage (1), stage (2) and stage (3), as follows:
adding 20 g of a first part of silicon source tetra-n-propyl orthosilicate and noble metal source platinum hydroxide into an alkaline template n-butylamine aqueous solution, uniformly stirring and mixing, placing the mixture into a stainless steel sealed reaction kettle, raising the kettle temperature to 180 ℃ from room temperature at a heating rate of 15 ℃/min, and crystallizing for 30 hours at the temperature to obtain a first mixture, wherein the molar ratio of the silicon source to the alkaline template to water in the first mixture is 50: 10: 500.
the reaction results are listed in table 1.
Example 18
In a fixed bed reactor, the same 5% Ru/TS-1 titanium silicalite molecular sieve catalyst as in example 15 is adopted, in the presence of a solvent methanol, a mixed gas containing hydrogen and oxygen is firstly introduced from the top end of the reactor, a diluent gas nitrogen is introduced from the top end of the reactor, a first reaction is carried out under the conditions that the temperature is 40 ℃ and the pressure is 2.0MPa, and after 1 hour, propylene is introduced into the reactor from the middle part of the reactor to continuously carry out a second reaction under the conditions that the temperature is 40 ℃ and the pressure is 2.0 MPa. The molar ratio of propylene, oxygen, hydrogen and diluent gas is 1: 5: 5: 10, the mass ratio of the methanol to the catalyst is 100: 1, the mass ratio of propylene to the catalyst is 4: 1. the total liquid hourly space velocity is 0.5h-1The reaction was carried out at 40 ℃ and 2.0MPa for 2 hours, and the samples were taken and analyzed, and the results are shown in Table 1.
Comparative example 1
This comparative example differs from example 1 in that hydrogen, oxygen and propylene were simultaneously fed into the reactor from the middle of the reactor to carry out the reaction.
Comparative example 2
The comparative example differs from example 1 in that the catalyst used was a TS-1 titanium silicalite catalyst with no palladium loading.
TABLE 1
| Numbering | Propylene conversion/% | Effective utilization of hydrogen/%) | Propylene oxide selectivity/%) |
| Example 1 | 2.8 | 43 | 82 |
| Example 2 | 7.6 | 62 | 90 |
| Example 3 | 9.2 | 73 | 93 |
| Example 4 | 8.9 | 69 | 92 |
| Example 5 | 8.0 | 66 | 91 |
| Example 6 | 7.8 | 64 | 90 |
| Example 7 | 8.2 | 65 | 91 |
| Example 8 | 6.5 | 58 | 87 |
| Example 9 | 6.0 | 59 | 86 |
| Example 10 | 10.6 | 85 | 95 |
| Example 11 | 10.1 | 82 | 94 |
| Example 12 | 9.8 | 79 | 93 |
| Example 13 | 9.3 | 74 | 92 |
| Example 14 | 8.5 | 75 | 91 |
| Example 15 | 11.2 | 87 | 97 |
| Example 16 | 6.4 | 58 | 86 |
| Example 17 | 6.0 | 57 | 87 |
| Example 18 | 12.3 | 90 | 99 |
| Comparative example 1 | 1.7 | 31 | 78 |
| Comparative example 2 | 0 | 0 | 0 |
As can be seen from the results in Table 1, the propylene oxide prepared by the method of the present invention can significantly improve the conversion rate of propylene, the effective utilization rate of hydrogen, and the selectivity of propylene oxide.
The preferred embodiments of the present invention have been described in detail, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention.
It should be noted that the various technical features described in the above embodiments can be combined in any suitable manner without contradiction, and the invention is not described in any way for the possible combinations in order to avoid unnecessary repetition.
In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the disclosure of the present invention as long as it does not depart from the spirit of the present invention.
Claims (20)
1. A process for the production of propylene oxide, the process comprising: in a fixed bed reactor, in the presence of a solvent, enabling a mixed gas containing hydrogen and oxygen to contact propylene and a catalyst for reaction, wherein the mixed gas enters the reactor from the end part of the reactor, the propylene enters the reactor from the middle part of the reactor, and the catalyst is a titanium silicalite molecular sieve catalyst containing noble metal;
the preparation steps of the titanium silicalite molecular sieve containing noble metal comprise: (1) mixing a first part of silicon source, an optional first part of titanium source and a first part of alkaline template agent in the presence of an aqueous solvent, and then carrying out first crystallization to obtain a first mixture; (2) mixing the first mixture, a second part of silicon source, a second part of titanium source, an optional second part of alkaline template and optional water, and then carrying out second crystallization to obtain a second mixture, and then recovering a solid product; wherein step (1) and/or step (2) is carried out in the presence of a noble metal source;
the preparation steps of the titanium silicalite molecular sieve containing noble metal further comprise: step (1) and/or step (2) is/are carried out in the presence of a vanadium compound.
2. The process of claim 1, wherein the end of the reactor is the top end and/or the bottom end of the reactor.
3. The process of claim 1, wherein the molar ratio of propylene, oxygen, and hydrogen is 1: (0.1-10): (0.1-10), wherein the mass ratio of the solvent to the catalyst is (20-1000): 1, the mass ratio of the propylene to the catalyst is (0.1-50): 1.
4. the process of claim 1, wherein the titanium silicalite molecular sieve is at least one selected from the group consisting of an MFI-type titanium silicalite molecular sieve, an MEL-type titanium silicalite molecular sieve, a BEA-type titanium silicalite molecular sieve, an MWW-type titanium silicalite molecular sieve, an MOR-type titanium silicalite molecular sieve, a TUN-type titanium silicalite molecular sieve, and a hexagonal structure titanium silicalite molecular sieve.
5. The method according to claim 1, wherein the noble metal is at least one selected from the group consisting of Ru, Rh, Pd, Re, Os, Ir, Pt, Ag, and Au.
6. The method of any one of claims 1-5, wherein the molar ratio of the silicon source, the titanium source, the basic templating agent, and the water in the second mixture is 100: (0.5-5): (10-50): (500-: the mole ratio of the silicon source is (0.1-10): 100, the silicon source is SiO2The titanium source is calculated as TiO2The alkali source template is counted as N when containing nitrogen element, and the alkali source template is counted as OH when not containing nitrogen element-The noble metal source is calculated by a metal simple substance.
7. The method of claim 6, wherein the molar ratio of silicon source, basic templating agent, and water in the first mixture is 50: (10-50): (500-; the molar ratio of the first part of silicon source to the second part of silicon source is (1-10): 1, the silicon source is SiO2The titanium source is calculated as TiO2The alkali source template is counted as N when containing nitrogen element, and the alkali source template is counted as OH when not containing nitrogen element-And (6) counting.
8. The method of claim 7, wherein the molar ratio of the silicon source, the titanium source, the basic templating agent, and the water in the first mixture is 50: (0.25-1): (10-50): (500-5000).
9. The method of claim 6, wherein the conditions of the first crystallization comprise: the temperature is 80-220 ℃, and the time is 12-96 h; the conditions of the second crystallization include: the temperature is 140 ℃ and 180 ℃, and the time is 6-24 h.
10. The method of claim 9, wherein the first crystallization is sequentially subjected to stage (1), stage (2) and stage (3), the stage (1) being crystallized at 80-120 ℃ for 6-30 hours; the temperature of the stage (2) is raised to 180 ℃ and 220 ℃ for crystallization for 0.5 to 8 hours; the temperature of the stage (3) is reduced to 140 ℃ and 180 ℃ for crystallization for 6-48 hours.
11. The method of claim 10, wherein the temperature difference between stage (3) and stage (2) is at least 20 ℃; the temperature rising rate from the room temperature to the stage (1) is 0.1-20 ℃/min, the temperature rising rate from the stage (1) to the stage (2) is 1-50 ℃/min, and the temperature falling rate from the stage (2) to the stage (3) is 1-20 ℃/min.
12. The method according to claim 11, wherein the temperature difference between the stages (3) and (2) is 25-60 ℃.
13. The method of claim 6, wherein the basic templating agent is at least one selected from the group consisting of urea, quaternary ammonium base compounds, aliphatic amine compounds, and aliphatic alcohol amine compounds;
the silicon source is inorganic silicon source and/or organic silicon source, the inorganic silicon source is at least one selected from silicate, silica sol and silica gel, the organic silicon source is at least one selected from silicon-containing compound shown in formula I, in the formula I, R is1、R2、R3And R4Each is C1-C4Alkyl of (2)The base group is a group of a compound,
the titanium source is inorganic titanium salt and/or organic titanate;
the noble metal source is at least one selected from the group consisting of an oxide of a noble metal, a halide of a noble metal, a carbonate of a noble metal, a nitrate of a noble metal, an ammonium nitrate salt of a noble metal, an ammonium chloride salt of a noble metal, a hydroxide of a noble metal, and a complex of a noble metal.
14. The process according to claim 1, wherein the molar ratio of the vanadium compound to the silicon source is (0.1-10): 100, the vanadium compound is calculated as V, and the silicon source is calculated as SiO2Counting;
the vanadium compound is at least one selected from the group consisting of an oxide of vanadium, a halide of vanadium, vanadic acid, a vanadate, a carbonate of vanadium, a nitrate of vanadium, a sulfate of vanadium, and a hydroxide of vanadium.
15. The process of claim 14, wherein step (1) is carried out in the presence of the vanadium compound.
16. The method according to claim 1, wherein the solvent is at least one selected from the group consisting of water, methanol, ethanol, n-propanol, isopropanol, tert-butanol, isobutanol, acetone, butanone, and acetonitrile.
17. The method of claim 1, wherein the method further comprises: the reaction is carried out in the presence of a diluent gas, the molar ratio of the diluent gas to propylene being (1-100): 1, the diluent gas is at least one selected from the group consisting of nitrogen, argon, helium, neon, carbon dioxide, methane, ethane, and propane.
18. The method of claim 1, wherein the molar ratio of hydrogen to oxygen in the mixed gas is (0.5-2): 1.
19. the method of claim 1, wherein the method further comprises: in the presence of a solvent, the mixed gas enters the reactor from the end part of the reactor to contact with a catalyst for a first reaction to obtain a first reactant, and then the propylene enters the reactor from the middle part of the reactor to continue to contact with the first reactant and the catalyst for a second reaction.
20. The method of claim 19, wherein the conditions of the first reaction are: the temperature is 0-80 ℃, the pressure is 0.1-30MPa, and the total liquid hourly space velocity is 0.02-20h-1(ii) a The conditions of the second reaction are as follows: the temperature is 0-80 ℃, the pressure is 0.1-30MPa, and the total liquid hourly space velocity is 0.02-20h-1。
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| CN101619048A (en) * | 2008-06-30 | 2010-01-06 | 中国石油化工股份有限公司 | Method for synthesizing propylene oxide |
| CN101683984A (en) * | 2008-09-27 | 2010-03-31 | 中国石油化工股份有限公司 | Method for synthesizing titanium silicon materials containing noble metal |
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| CN101619048A (en) * | 2008-06-30 | 2010-01-06 | 中国石油化工股份有限公司 | Method for synthesizing propylene oxide |
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