Method for preparing a silicotitanium molecular sieve

Abstract

The application relates to the field of molecular sieve preparation and discloses a preparation method of a titanium-silicon molecular sieve. The method comprises the following steps: 1) mixing an organic silicon source, a titanium source, an alkaline template agent and water to obtain a mixture; 2) performing alcohol removal treatment on the mixture obtained in the step 1) to obtain an alcohol removal treatment product; 3) performing crystallization treatment on the alcohol removal treatment product obtained in the step 2) to obtain a crystallization treatment product; 4) performing solid-liquid separation on the crystallization treatment product obtained in the step 3) to obtain a solid phase and a liquid phase; 5) performing washing, drying and first calcination on the solid phase obtained in the step 4) to obtain the titanium-silicon molecular sieve; and 6) contacting the liquid phase obtained in the step 3) and / or the washing liquid obtained in the step 4) with a porous material, wherein the specific surface area and the pore size of the porous material are larger than those of the titanium-silicon molecular sieve. According to the method, the COD value in the generated waste liquid can be greatly reduced in the preparation process.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of molecular sieve preparation, in particular to a preparation method of titanium silicalite molecular sieve. BACKGROUND

[0002] Titanium silicalite molecular sieve is a commonly used catalyst in chemical production, especially in the field of petroleum refining and petrochemical industry. TS-1 molecular sieve is a new type of titanium silicalite molecular sieve with excellent catalytic selectivity oxidation performance, which is formed by introducing transition metal element titanium into the molecular sieve framework with ZSM-5 structure. TS-1 not only has the catalytic oxidation of titanium, but also has the shape selection and excellent stability of ZSM-5 molecular sieve, and successfully realizes industrial application in the process of preparing cyclohexanone oxime by catalytic ammonia oxidation of cyclohexanone.

[0003] However, in the production process of titanium silicalite molecular sieve, a large amount of waste liquid containing organic amine, alcohol and the like is generated, the COD value of the waste liquid can be as high as 120000 mg / L, which has strong toxic effect on the ecological environment and cannot be directly discharged. However, there is no effective and low-cost treatment method found at present. SUMMARY

[0004] The purpose of the present application is to overcome the problem of difficult treatment of high COD value waste liquid in the preparation process of titanium silicalite molecular sieve in the prior art, and to provide a preparation method of titanium silicalite molecular sieve. The titanium silicalite molecular sieve obtained by the method has excellent catalytic performance, and can greatly reduce the COD value of the waste liquid generated in the preparation process.

[0005] In order to achieve the above purpose, the present application provides a preparation method of titanium silicalite molecular sieve, which comprises the following steps: 1) mixing an organic silicon source, a titanium source, an alkaline template agent and water to obtain a mixture;

[0006] 2) performing alcohol removal treatment on the mixture obtained in step 1) to obtain an alcohol removal treatment product;

[0007] 3) performing crystallization treatment on the alcohol removal treatment product obtained in step 2) to obtain a crystallization treatment product;

[0008] 4) performing solid-liquid separation on the crystallization treatment product obtained in step 3) to obtain a solid phase and a liquid phase;

[0009] 5) performing washing, drying and first calcination on the solid phase obtained in step 4) to obtain titanium silicalite molecular sieve;

[0010] 6) contacting the liquid phase obtained in step 3) and / or the washing liquid obtained in step 4) with a porous material,

[0011] wherein the specific surface area and pore size of the porous material are larger than those of the titanium silicalite molecular sieve.

[0012] Preferably, in step 6), the porous material is one or more of Y-type molecular sieve, β-type molecular sieve and mesoporous molecular sieve.

[0013] Preferably, the Y-type molecular sieve is one or more of NaY molecular sieve, NH4Y molecular sieve, HY molecular sieve, PHY, USY molecular sieve and ReY molecular sieve.

[0014] Preferably, the β-type molecular sieve is Naβ molecular sieve and / or Hβ molecular sieve.

[0015] Preferably, the mesoporous molecular sieve is one or more of SBA-15 mesoporous molecular sieve, SBA-1 mesoporous molecular sieve and M41S, MCM-22 molecular sieve and MCM-68 molecular sieve mesoporous molecular sieve.

[0016] More preferably, the porous material is HY molecular sieve and / or SBA-15 mesoporous molecular sieve.

[0017] Preferably, in step 6), the mass ratio of the liquid phase obtained in step 3) and / or the washing liquid obtained in step 4) to the porous material is 1-500:1.

[0018] More preferably, when the contacting is performed, the mass ratio of the liquid phase obtained in step 3) and / or the washing liquid obtained in step 4) to the porous material is 1-50:1.

[0019] Further preferably, when the contacting is performed, the mass ratio of the liquid phase obtained in step 3) and / or the washing liquid obtained in step 4) to the porous material is 1-10:1.

[0020] Preferably, the conditions of the contacting include that the contacting temperature is 5-100℃ and the contacting time is 3h or less.

[0021] More preferably, the conditions of the contacting include that the contacting temperature is 20-80℃ and the contacting time is 1-60min.

[0022] Further preferably, the conditions of the contacting include that the contacting temperature is 20-45℃ and the contacting time is 20-50min.

[0023] Preferably, in step 1), the organic silicon source is selected from one or more of tetramethyl orthosilicate, tetraethyl orthosilicate, tetra-n-propyl orthosilicate and tetra-n-butyl orthosilicate.

[0024] More preferably, the organic silicon source is tetraethyl orthosilicate.

[0025] Preferably, in step 1), the titanium source is an organic titanium source and / or an inorganic titanium source.

[0026] Preferably, the inorganic titanium source is selected from one or more of TiCl4, Ti(SO4)2, TiOCl2, titanium hydroxide, titanium oxide, titanium nitrate and titanium phosphate.

[0027] Preferably, the organic titanium source is selected from titanium fatty alcoholate and / or organic titanate.

[0028] Preferably, the titanium fatty alcoholate is selected from one or more of titanium isopropoxide, titanium n-propoxide, titanium n-butoxide and titanium isobutoxide.

[0029] Preferably, the organic titanate has a general formula of M4TiO4, wherein M is an alkyl group having 1-4 carbon atoms.

[0030] Preferably, the organic titanate is selected from one or more of titanium tetrapropoxide, titanium tetrabutoxide and titanium tetraethoxide.

[0031] Preferably, in step 1), the base template agent is an organic base template agent and / or an inorganic base template agent.

[0032] Preferably, the inorganic base template agent is selected from one or more of aqueous ammonia, sodium hydroxide, potassium hydroxide and barium hydroxide.

[0033] Preferably, the organic base template agent is selected from one or more of urea, quaternary ammonium base compound, fatty amine compound and alcohol amine compound.

[0034] Preferably, the quaternary ammonium base compound has a general formula of (R 1 )4NOH, wherein R 1 is an alkyl group having 1-4 carbon atoms.

[0035] Preferably, the quaternary ammonium base compound is tetrapropylammonium hydroxide.

[0036] Preferably, the fatty amine compound has a general formula of R 2 (NH2) n , wherein R 2 is an alkyl group having 1-6 carbon atoms or an alkylene group having 1-6 carbon atoms, and n is 1 or 2.

[0037] Preferably, the fatty amine compound is selected from one or more of ethylamine, n-butylamine, butanediamine and hexanediamine.

[0038] Preferably, the alcohol amine compound has a general formula of (HOR 3 ) m NH (3-m) , wherein R 3 is an alkyl group having 1-4 carbon atoms, and m is 1, 2 or 3.

[0039] Preferably, the alcohol amine compound is selected from one or more of monoethanolamine, diethanolamine and triethanolamine.

[0040] Preferably, in step 1), the mass ratio of the organosilicon source, the titanium source, the alkaline template agent and water is 100:(0.2-5):(1-20):(250-2500).

[0041] Preferably, the mass ratio of the organosilicon source, the titanium source, the alkaline template agent and water is 100:(1-3):(5-15):(300-1000).

[0042] Preferably, in step 2), the conditions of the alcohol removal treatment include: temperature of 60-99℃, time of 2-48h.

[0043] More preferably, the conditions of the alcohol removal treatment include: temperature of 80-95℃, time of 3-24h.

[0044] Preferably, in step 3), the conditions of the crystallization treatment include: temperature of 140-200℃, time of 12-96h.

[0045] More preferably, in step 3), the conditions of the crystallization treatment include: temperature of 150-180℃, time of 24-72h.

[0046] Preferably, in step 5), the conditions of the first calcination include: temperature of 300-800℃, time of 0.5-12h.

[0047] Preferably, the conditions of the first calcination include: temperature of 400-600℃, time of 1-5h.

[0048] Preferably, the method further comprises a step of second calcination of the porous material after the contacting in step 6).

[0049] Preferably, the conditions of the second calcination include: temperature of 500-800℃, time of 1-5h.

[0050] More preferably, the conditions of the second calcination include: temperature of 500-600℃, time of 2-3h.

[0051] Through the above technical solution, the titanium silicalite molecular sieve prepared as a catalyst has excellent catalytic performance and service life when participating in a catalytic reaction.

[0052] In addition, through the technical solution in the present application, the impurities in the waste liquid generated in the production process of the titanium silicalite molecular sieve can be adsorbed by the porous material, thereby greatly reducing the COD value of the waste liquid generated in the production process of the titanium silicalite molecular sieve.

[0053] The COD value in the waste liquid can be reduced to below 50 mg / L, so that direct discharge can be achieved.

[0054] In addition, when the porous material after contacting the waste liquid is calcined, the COD substance can be converted into carbon dioxide and water at high temperature, achieving harmless treatment, and the calcined porous material can be reused, greatly reducing the treatment cost of the titanium silicalite waste liquid.

[0055] Other features and advantages of the present application will be described in detail in the following specific embodiments. DETAILED DESCRIPTION

[0056] The endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The endpoints of the ranges and any values are understood to be approximate values. The exact numerical values of the endpoints of the ranges and the separate numerical values are not to be construed as limiting, but rather as approximations. Any numerical value, however, can include fractions of the value, ranges tailored to the exact number of significant digits in the value, and other increments that can not be expressly addressed or described below. The endpoints of the ranges and any values are not limited to the same unit or units in which that value is expressed.

[0057] The present application provides a preparation method of titanium silicalite, which comprises:

[0058] 1) mixing an organic silicon source, a titanium source, an alkaline template agent and water to obtain a mixture;

[0059] 2) performing alcohol removal treatment on the mixture obtained in step 1) to obtain an alcohol removal treatment product;

[0060] 3) performing crystallization treatment on the alcohol removal treatment product obtained in step 2) to obtain a crystallization treatment product;

[0061] 4) performing solid-liquid separation on the crystallization treatment product obtained in step 3) to obtain a solid phase and a liquid phase;

[0062] 5) performing washing, drying and first calcination on the solid phase obtained in step 4) to obtain titanium silicalite;

[0063] 6) contacting the liquid phase obtained in step 3) and / or the washing liquid obtained in step 4) with a porous material,

[0064] The specific surface area and the pore size of the porous material are greater than those of the titanium silicalite.

[0065] According to the present application, the waste liquid generated in the preparation process of the titanium silicalite is contacted with the porous material having a specific surface area and a pore size greater than those of the titanium silicalite, so that the COD value of the waste liquid can be greatly reduced in a short time.

[0066] In the present application, the waste liquid refers to mother liquor and / or washing liquid generated in the preparation process of titanium silicalite molecular sieve. The mother liquor is the liquid phase obtained after the solid-liquid separation of the crystallization product in the method of the present application, and the washing liquid is the washing liquid generated after the washing of the solid phase obtained after the solid-liquid separation of the crystallization product in the method of the present application.

[0067] In step 1) of the present application, the organic silicon source, the titanium source, the alkaline template agent and water are mixed to obtain a mixture, and the method and order of mixing are not particularly limited, and can be carried out according to the conventional mixing method and order in the art, as long as the purpose of mixing the substances is achieved.

[0068] According to the present application, the mass ratio of the organic silicon source, the titanium source, the alkaline template agent and water is not particularly limited, and can be selected conventionally in the art. Preferably, in step 1), the mass ratio of the organic silicon source, the titanium source, the alkaline template agent and water is 100:(0.2-5):(1-20):(250-2500), more preferably, the mass ratio of the organic silicon source, the titanium source, the alkaline template agent and water is 100:(1-3):(5-15):(300-1000). By controlling the mass ratio of the substances in the range, the performance of the titanium silicalite molecular sieve prepared can be further improved.

[0069] In the present application, the organic silicon source can be various organic silicon sources conventionally used in the art, and is not particularly limited. Preferably, the organic silicon source is selected from one or more of tetramethyl orthosilicate, tetraethyl orthosilicate, tetra-n-propyl orthosilicate and tetra-n-butyl orthosilicate; more preferably, the organic silicon source is tetraethyl orthosilicate.

[0070] In the present application, the titanium source can be various organic titanium sources and / or inorganic titanium sources conventionally used in the art, and is not particularly limited.

[0071] The organic titanium source can be selected from titanium fatty alcohol and / or organic titanate. As the titanium fatty alcohol, for example, one or more of titanium isopropoxide, titanium n-propoxide, titanium n-butoxide and titanium isobutoxide can be selected, and titanium isopropoxide is preferred.

[0072] As the organic titanate, the organic titanate of general formula M4TiO4 is preferred, wherein M is preferably an alkyl group having 1-4 carbon atoms, and the 4 M can be the same or different; more preferably, the organic titanate is selected from one or more of tetrapropyl titanate (including various isomers of tetrapropyl titanate, such as tetraisopropyl titanate and tetra-n-propyl titanate), tetrabutyl titanate (various isomers of tetrabutyl titanate, such as tetra-n-butyl titanate) and tetraethyl titanate.

[0073] In the present application, the inorganic titanium source can be selected from one or more of TiCl4, Ti(SO4)2, TiOCl2, titanium hydroxide, titanium oxide, titanium nitrate and titanium phosphate, and preferably is TiCl4.

[0074] In the present application, the base template agent can be various organic base template agents and / or inorganic base template agents commonly used in the art.

[0075] As the organic base template agent, one or more of urea, quaternary ammonium base compound, fatty amine compound and alcohol amine compound can be selected.

[0076] The quaternary ammonium base compound can be various organic quaternary ammonium bases commonly used in the art, and the general formula of the quaternary ammonium base compound can be (R 1 )4NOH, wherein R 1 is an alkyl group having 1-4 carbon atoms, for example, R 1 may be methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, and t-butyl, etc.

[0077] Preferably, the quaternary ammonium base compound is tetrapropylammonium hydroxide, thereby further ensuring the performance of the titanium silicalite molecular sieve prepared.

[0078] In the present application, the fatty amine compound can be various fatty amine compounds commonly used in the art without particular limitation, and the fatty amine compound can be a compound formed by replacing at least one hydrogen in NH3 with an aliphatic hydrocarbon group (preferably an alkyl group).

[0079] The general formula of the fatty amine compound can be R 2 (NH2) n , wherein R 2 is an alkyl group having 1-6 carbon atoms or an alkylene group having 1-6 carbon atoms, and n is 1 or 2.

[0080] When n is 1, R 2 is an alkyl group having 1-6 carbon atoms, and at this time, R 2 may be a linear alkyl group of C1-C6 or a branched alkyl group of C3-C6, and specifically, R 2 may be methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, t-butyl, n-pentyl, neopentyl, iso-pentyl, t-pentyl or n-hexyl, etc.

[0081] When n is 2, R 2 is an alkylene group having 1-6 carbon atoms, and at this time, R 2 may be a linear alkylene group of C1-C6 or a branched alkylene group of C3-C6, and specifically, R 2It can be methylene, ethylene, n-propylene, n-butylene, n-pentylene or n-hexylene, etc.

[0082] Preferably, the fatty amine compound is selected from one or more of ethylamine, n-butylamine, butanediamine and hexanediamine.

[0083] The alcohol amine compound can be various alcohol amine compounds commonly used in the art, which can be a compound formed by replacing at least one hydrogen in NH3 with a hydroxyl-containing aliphatic hydrocarbon group (preferably an alkyl group).

[0084] The general formula of the alcohol amine compound can be (HOR 3 ) m NH (3-m) , wherein R 3 is an alkyl group having 1-4 carbon atoms, and m is 1, 2 or 3. Specifically, for example, R 4 may be methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, and tert-butyl, etc.

[0085] Preferably, the alcohol amine compound is selected from one or more of monoethanolamine, diethanolamine and triethanolamine.

[0086] According to the present application, the inorganic base template agent can be selected from various inorganic base template agents commonly used in the art, for example, it can be selected from ammonia, an alkali or alkaline earth metal cation base, etc., specifically, the inorganic base template agent can be selected from sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, potassium carbonate and barium hydroxide, etc.

[0087] Preferably, the inorganic base template agent is one or more of ammonia, sodium hydroxide, potassium hydroxide and barium hydroxide.

[0088] According to the present application, after mixing the organosilicon source, titanium source, base template agent and water, the obtained mixture will undergo a hydrolysis reaction, in order to promote the progress of the hydrolysis reaction, the mixture is subjected to alcohol chasing treatment.

[0089] The alcohol chasing treatment conditions include a temperature of 60-99°C and a time of 2-48h; preferably, the alcohol chasing treatment conditions include a temperature of 80-95°C and a time of 3-24h. By performing alcohol chasing treatment within the above-mentioned condition range, the mixture can more efficiently achieve hydrolysis, and thus a titanium silicalite with better performance can be prepared, which can significantly improve the catalyst performance and service life of the prepared titanium silicalite.

[0090] In addition, in the present application, through the alcohol chasing treatment, part of the alcohol substances that will exist in the waste liquid in the subsequent process can be removed in advance, thereby reducing the COD value of the waste liquid generated in the preparation of titanium silicalite.

[0091] According to the present application, after the alcohol removal treatment, the obtained alcohol removal treatment product is subjected to a crystallization treatment, and the method of the crystallization treatment is not particularly limited in the present application, and a crystallization treatment method commonly used in the art can be used. Preferably, the crystallization treatment is carried out in a closed environment, and stirring is carried out during the crystallization treatment, thereby promoting the progress of the crystallization reaction and improving the performance of the prepared titanium silicalite molecular sieve.

[0092] In the present application, the conditions of the crystallization treatment are not particularly limited, for example, the conditions of the crystallization treatment can include a temperature of 140-200°C and a time of 12-96h; preferably, the conditions of the crystallization treatment include a temperature of 150-180°C and a time of 24-72h. By carrying out the crystallization treatment under the above conditions, the effect of the crystallization treatment can be further ensured, and the performance of the obtained titanium silicalite molecular sieve can be improved.

[0093] According to the present application, after the crystallization treatment, the crystallization product is subjected to solid-liquid separation to obtain a solid phase and a liquid phase.

[0094] In the present application, the method of the solid-liquid separation is not particularly limited, and various methods of solid-liquid separation commonly used in the art can be used. For example, various methods such as plate and frame filtration, tank washing, inorganic ceramic membrane filtration, and belt filter filtration can be used, as long as the product obtained by the crystallization treatment can be subjected to solid-liquid separation, which will not be described here.

[0095] According to the present application, the solid phase obtained by the solid-liquid separation is further subjected to washing, drying, and first calcination, thereby obtaining a titanium silicalite molecular sieve.

[0096] In the present application, the washing is a conventional operation in the art, and the method thereof is not particularly limited, which will not be described here.

[0097] In the present application, in order to remove the residual water after washing, the obtained solid phase is further subjected to drying, and the conditions of the drying are not particularly limited, for example, the temperature of the drying can be 80-150°C, and the time of the drying can be 0.5-24h; preferably, the temperature of the drying is 110-130°C, and the time of the drying is 1-8h.

[0098] Then, the dried product is subjected to first calcination, and the conditions of the first calcination are not particularly limited, the temperature of the first calcination can be 300-800°C, and the time can be 0.5-12h; preferably, the conditions of the first calcination include a temperature of 400-600°C and a time of 1-5h. By carrying out the first calcination under the above conditions, the quality of the obtained titanium silicalite molecular sieve can be ensured, and its catalytic performance and service life can be improved.

[0099] The various substances remaining in the liquid phase obtained by the solid-liquid separation and / or the washing liquid obtained by the washing described above make the waste liquid have a relatively high COD value, and thus cannot be directly discharged.

[0100] According to the present application, the liquid phase obtained by the solid-liquid separation and / or the washing liquid obtained by the washing described above is contacted with a porous material, so that the COD in the waste liquid is removed, and the obtained waste liquid meets the discharge standard. The specific surface area and pore size of the porous material are required to be greater than those of the prepared titanium-silicon molecular sieve.

[0101] According to the present application, preferably, the specific surface area of the porous material is 30-300% greater than that of the titanium-silicon molecular sieve, and more preferably, the specific surface area of the porous material is 40-80% greater than that of the titanium-silicon molecular sieve.

[0102] Preferably, the pore size of the porous material is 30-2000% greater than that of the titanium-silicon molecular sieve, and more preferably, 30-1100%.

[0103] In the present application, the porous material can be one or more of Y-type molecular sieves, β-type molecular sieves and mesoporous molecular sieves having a specific surface area and pore size greater than those of the prepared titanium-silicon molecular sieve.

[0104] As the Y-type molecular sieve, for example, one or more of NaY molecular sieve, NH4Y molecular sieve, HY molecular sieve, PHY molecular sieve, USY molecular sieve and ReY molecular sieve can be selected, and preferably, HY molecular sieve and / or PHY molecular sieve.

[0105] As the β-type molecular sieve, for example, Naβ molecular sieve and / or Hβ molecular sieve can be selected, and preferably, Hβ molecular sieve.

[0106] As the mesoporous molecular sieve, for example, one or more of SBA-15 mesoporous molecular sieve, SBA-1 mesoporous molecular sieve, M41S mesoporous molecular sieve, MCM-22 molecular sieve and MCM-68 molecular sieve can be selected, and preferably, SBA-15 mesoporous molecular sieve.

[0107] In the present application, preferably, the porous material is one or more of HY molecular sieve, Hβ molecular sieve and SBA-15 mesoporous molecular sieve; and more preferably, HY molecular sieve and / or SBA-15 mesoporous molecular sieve.

[0108] The porous material described above can strongly adsorb impurities in the waste liquid, so as to greatly reduce the COD value in the waste liquid.

[0109] According to the present application, the mass ratio of the liquid phase and / or the washing liquid to the porous material can be in a range of 1-500:1, preferably 1-50:1.

[0110] According to the present application, the mass ratio of the liquid phase and / or the washing liquid to the porous material can be in a range of 1-500:1, preferably 1-50:1.

[0111] In addition, in the present application, the contacting conditions include a contacting temperature of 5-100°C and a contacting time of 3h or less, preferably a contacting temperature of 20-80°C and a contacting time of 1-60min. Under the above conditions, the liquid phase and / or the washing liquid can be contacted with the porous material to reduce the COD value in the waste liquid to a greater extent.

[0112] According to the present application, if the COD value in the obtained waste liquid is high or the amount of waste liquid to be treated is large, preferably, a multi-stage contacting is adopted.

[0113] In the present application, the multi-stage contacting refers to that the waste liquid is contacted with the porous material once, and then the waste liquid after the first contacting is contacted with the porous material again for the second time, the third time, etc., until the emission standard is met.

[0114] In addition, in the present application, after the contacting, the porous material adsorbs various impurities such as organic matters, and then can be subjected to a second calcination for harmless treatment and recycling.

[0115] Specifically, the porous material after the contacting with the waste liquid in step 6) can be first dried, and the drying is not particularly limited, for example, flash drying can be adopted. Then, the porous material is subjected to a second calcination, so that the impurities adsorbed therein are converted into carbon dioxide and water by high-temperature calcination, realizing the harmless treatment and recovering the adsorption capacity of the porous material.

[0116] According to the present application, the second calcination conditions can be a second calcination temperature of 500-800°C and a second calcination time of 1-5h, preferably a second calcination temperature of 500-600°C and a second calcination time of 2-3h. Thus, the impurities in the porous material can be removed by the second calcination, and the porous material after the second calcination can be further contacted with the waste liquid to remove the COD in the waste liquid, thereby realizing recycling.

[0117] The present application will be described in detail below by way of examples and comparative examples.

[0118] In the following examples and comparative examples, the raw materials used are all commercially available unless otherwise specified.

[0119] Comparative Example 1

[0120] Prepared according to the method described in Zeolites, 1992, Vol. 12, pp. 943-950, by the following procedure:

[0121] 1) At 20°C, 22.5 g of tetraethyl orthosilicate was mixed with 7.0 g of tetrapropylammonium hydroxide as a template agent, and 59.8 g of distilled water was added. After stirring the mixture, hydrolysis was carried out at 60°C for 1 h to obtain a hydrolysis solution of tetraethyl orthosilicate;

[0122] 2) A solution composed of 1.1 g of tetrabutyl titanate and 5.0 g of anhydrous isopropanol was slowly added to the hydrolysis solution under vigorous stirring, and the resulting mixture was stirred at 75°C for 3 h to obtain a clear transparent colloid;

[0123] 3) The colloid was placed in a stainless steel sealed autoclave, and was kept at a temperature of 170°C for 36 h to obtain a mixture of crystallization products;

[0124] 4) The resulting mixture was filtered, and the obtained solid phase and liquid phase were collected separately;

[0125] 5) The solid phase material was washed with water and then dried at 110°C for 1 h, followed by calcination at 500°C for 6 h to obtain titanium silicalite D1. The X-ray diffraction spectrum (XRD pattern) of D1 was determined, and it was determined that D1 was a titanium silicalite with MFI structure;

[0126] 6) The COD value of the liquid phase obtained by filtration was determined, and the results are shown in Table 1.

[0127] Example 1

[0128] 1) Tetraethyl orthosilicate, titanium isopropoxide, tetrapropylammonium hydroxide and water were mixed in a mass ratio of 100:2:10:500 to obtain a mixture;

[0129] 2) The mixture was subjected to alcohol removal treatment at 90°C for 12 h to obtain an alcohol removal treatment product;

[0130] 3) The alcohol removal treatment product was transferred to a stainless steel sealed autoclave, and was subjected to crystallization treatment at 170°C for 48 h to obtain a crystallization treatment product;

[0131] 4) The crystallization treatment product was filtered to obtain a solid phase and a liquid phase;

[0132] 5) After washing and drying the solid phase at 110°C for 1 h, calcining at 550°C for 3 h, a titanium silicalite S1 was obtained, which had a specific surface area of 415 m2 / g, a pore size of 0.55 nm, and an X-ray diffraction spectrum characteristic of a titanium silicalite with MFI structure; 2

[0133] 6) The liquid phase of step 4) was contacted with SBA-15 mesoporous molecular sieves (with a specific surface area of 730 m 2 / g and a pore size of 6.4 nm) at a mass ratio of liquid phase to SBA-15 mesoporous molecular sieves of 1:1, for 30 min at 60°C.

[0134] The COD value in the liquid phase after contact with SBA-15 mesoporous molecular sieves is shown in Table 1.

[0135] Example 2

[0136] The procedure of Example 1 was followed, except that:

[0137] In step 6), the liquid phase was contacted with HY molecular sieves (with a specific surface area of 600 m 2 / g and a pore size of 0.75 nm) under the same conditions.

[0138] The COD value in the liquid phase after contact with HY molecular sieves is shown in Table 1.

[0139] Example 3

[0140] The procedure of Example 1 was followed, except that:

[0141] In step 6), the contact time was 30 min and the contact temperature was 20°C.

[0142] The COD value in the liquid phase after contact with SBA-15 mesoporous molecular sieves is shown in Table 1.

[0143] Example 4

[0144] The procedure of Example 1 was followed, except that:

[0145] In step 6), the mass ratio of liquid phase to SBA-15 mesoporous molecular sieves was 2:1.

[0146] The COD value in the liquid phase after contact with SBA-15 mesoporous molecular sieves is shown in Table 1.

[0147] Example 5

[0148] The procedure of Example 1 was followed, except that:

[0149] ​In step 6), the mass ratio of the liquid phase to the SBA-15 mesoporous molecular sieve is 50:1.

[0150] The COD value in the liquid phase after contacting with the SBA-15 mesoporous molecular sieve is shown in Table 1.

[0151] Example 6

[0152] The method of Example 1 is followed, except that,

[0153] In step 6), the liquid phase is contacted with Hβ molecular sieve (specific surface area of 650 m 2 / g, pore size of 0.7 nm) under the same conditions.

[0154] The COD value in the liquid phase after contacting with the Hβ molecular sieve is shown in Table 1.

[0155] Example 7

[0156] The method of Example 1 is followed, except that,

[0157] In step 6), the liquid phase is contacted with NaY molecular sieve (specific surface area of 580 m 2 / g, pore size of 0.76 nm) under the same conditions.

[0158] The COD value in the liquid phase after contacting with the NaY molecular sieve is shown in Table 1.

[0159] Comparative Example 2

[0160] The method of Example 1 is followed, except that,

[0161] The liquid phase is not subjected to the contacting treatment in step 6).

[0162] The COD value in the liquid phase is shown in Table 1.

[0163] Table 1

[0164]

[0165] As can be seen from the results in Table 1, using the technical solution of the present application, the COD value in the titanium silicalite waste liquid after contacting with the porous material is significantly reduced.

[0166] Test Example

[0167] This test example is used to test the application of the titanium silicalite molecular sieve prepared in Example 1 and Comparative Example 1 as a catalyst in the ammoximation reaction.

[0168] The reaction is carried out in a 150 ml reactor volume, using magnetic stirring, oil bath heating, and continuous feeding of raw materials and reaction products into the reactor, and the titanium silicalite catalyst is intercepted in the reactor.

[0169] The process parameters are as follows: H2O2: cyclohexanone (molar ratio) = 1.1:1, ammonia: cyclohexanone (molar ratio) = 1.5:1, t-butyl alcohol: cyclohexanone (molar ratio) = 3.3:1, catalyst concentration is 2% by weight, average residence time of the material is 70 min, reaction temperature is 76°C, and reaction pressure is normal pressure.

[0170] The reaction products are quantitatively analyzed by gas chromatography, and on this basis, the cyclohexanone conversion rate and cyclohexanone oxime selectivity are calculated using the following formula:

[0171] Cyclohexanone conversion rate (%) = [(molar amount of cyclohexanone added - molar amount of unreacted cyclohexanone) / molar amount of cyclohexanone added] x 100%.

[0172] Cyclohexanone oxime selectivity (%) = [molar amount of cyclohexanone oxime produced / (molar amount of cyclohexanone added - molar amount of unreacted cyclohexanone)] x 100%.

[0173] The reaction results are shown in Table 2, wherein the stable operation time of the catalyst is calculated based on the single-pass operation time when the cyclohexanone conversion rate is >95%.

[0174] Table 2

[0175] No. Average conversion of cyclohexanone, % Average selectivity of cyclohexanone oxime, % Stable operation time of catalyst, h Comparative Example 1 95.1 93.5 26 Example 1 98.9 99.8 97

[0176] As can be seen from Table 2, the titanium silicalite prepared by the method of the present application has a much better catalytic effect than the titanium silicalite prepared in Comparative Example 1 when used as a catalyst, and the stable operation time of the titanium silicalite prepared in Example 1 of the present application is significantly increased.

[0177] The above describes preferred embodiments of the present application, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including combining various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the present application and fall within the protection scope of the present application.

Claims

1. A process for the preparation of a titanium silicalite molecular sieve, characterized by, The method comprises: 1) mixing an organic silicon source, a titanium source, an alkali template agent and water to obtain a mixture; 2) performing alcohol removal treatment on the mixture obtained in step 1) to obtain an alcohol removal treatment product; 3) performing crystallization treatment on the alcohol removal treatment product obtained in step 2) to obtain a crystallization treatment product; 4) performing solid-liquid separation on the crystallization treatment product obtained in step 3) to obtain a solid phase and a liquid phase; 5) performing washing, drying and first calcination on the solid phase obtained in step 4) to obtain a titanium silicalite molecular sieve; 6) contacting the liquid phase obtained in step 4) and / or the washing liquid obtained in step 5) with a porous material, wherein the specific surface area and pore size of the porous material are larger than those of the titanium silicalite molecular sieve, and the porous material is SBA-15 mesoporous molecular sieve, in step 6), when the contacting is performed, the mass ratio of the liquid phase obtained in step 4) and / or the washing liquid obtained in step 5) to the porous material is 1-10:

1.

2. The production method according to claim 1, wherein The conditions of the contacting include that the contacting temperature is 5-100℃, and the contacting time is 3h or less.

3. The production method according to claim 2, wherein The conditions of the contacting include that the contacting temperature is 20-80℃, and the contacting time is 1-60min.

4. The production method according to claim 3, wherein The conditions of the contacting include that the contacting temperature is 20-45℃, and the contacting time is 20-50min.

5. The production process according to any one of claims 1 to 4, wherein In step 1), the organic silicon source is selected from one or more of tetramethyl orthosilicate, tetraethyl orthosilicate, tetra-n-propyl orthosilicate and tetra-n-butyl orthosilicate.

6. The production method according to any one of claims 1 to 4, wherein In step 1), the titanium source is an organic titanium source and / or an inorganic titanium source; the organic titanium source is selected from a fatty alcohol titanium and / or an organic titanate; the general formula of the organic titanate is M4TiO4, wherein M is an alkyl group with 1-4 carbon atoms.

7. The production method according to claim 6, wherein In step 1), the inorganic titanium source is selected from one or more of TiCl4, Ti(SO4)2, TiOCl2, titanium hydroxide, titanium oxide, titanium nitrate and titanium phosphate; the fatty alcohol titanium is selected from one or more of titanium isopropoxide, titanium n-propoxide, titanium n-butoxide and titanium isobutoxide; the organic titanate is selected from one or more of titanium tetrapropoxide, titanium tetrabutoxide and titanium tetraethoxide.

8. The production method according to any one of claims 1 to 4, wherein In step 1), the alkali template agent is an organic alkali template agent and / or an inorganic alkali template agent; the organic alkali template agent is selected from one or more of urea, a quaternary ammonium base compound, a fatty amine compound and an alcohol amine compound; The general formula of the quaternary ammonium base compound is (R 1 )4NOH, wherein R 1 is an alkyl group having 1-4 carbon atoms; The general formula of the fatty amine compound is R 2 (NH2) n wherein R 2 is an alkyl group having 1-6 carbon atoms or an alkylene group having 1-6 carbon atoms, and n is 1 or 2. The general formula of the alcohol amine compound is (HOR 3 ) m NH (3-m) , wherein R 3 is an alkyl group with 1-4 carbon atoms, and m is 1, 2 or 3.

9. The production method according to claim 8, wherein In step 1), the inorganic alkali template agent is selected from one or more of aqueous ammonia, sodium hydroxide, potassium hydroxide and barium hydroxide; the quaternary ammonium base compound is tetrapropylammonium hydroxide; the fatty amine compound is selected from one or more of ethylamine, n-butylamine, butanediamine and hexanediamine; the alcohol amine compound is selected from one or more of monoethanolamine, diethanolamine and triethanolamine.

10. The method of making according to any one of claims 1-4, wherein, In step 1), the mass ratio of the organic silicon source, the titanium source, the alkali template agent and water is 100:(0.2-5):(1-20):(250-2500).

11. The production method according to claim 10, wherein The mass ratio of the organic silicon source, the titanium source, the alkali template agent and water is 100:(1-3):(5-15):(300-1000).

12. The method of making according to any one of claims 1-4, wherein, In step 2), the conditions of the alcohol removal treatment include that the temperature is 60-99℃, and the time is 2-48h; In step 3), the conditions of the crystallization treatment include: temperature of 140-200°C, time of 12-96h.

13. The method of making according to claim 12, wherein, In step 2), the conditions of the alcohol removal treatment include: temperature of 80-95°C, time of 3-24h; In step 3), the conditions of the crystallization treatment include: temperature of 150-180°C, time of 24-72h.

14. The method of making according to any one of claims 1-4, wherein, In step 5), the conditions of the first calcination include: temperature of 300-800°C, time of 0.5-12h.

15. The method of making according to claim 14, wherein, The conditions of the first calcination include: temperature of 400-600°C, time of 1-5h.

16. The method of making according to any one of claims 1-4, wherein, The method further includes a step of subjecting the porous material after the contacting in step 6) to a second calcination; The conditions of the second calcination include: temperature of 500-800°C, time of 1-5h.

17. The method of making according to claim 16, wherein, The conditions of the second calcination include: temperature of 500-600°C, time of 2-3h.

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