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    公开号:NL2014073A
    申请号:NL2014073
    申请日:2014-12-30
    公开日:2015-07-01
    发明作者:Nicoleta Cristina Nenu
    申请人:Shell Int Research；
    IPC主号:
    专利说明:

    TS2801-NL-NP IMPROVEMENTS RELATING TO EPOXIDATION CATALYSTS Field of the Invention
    This invention relates to a process for preparing a titanium-based catalyst active in epoxidation reactions, a titanium-based catalyst obtainable by this process, and a process for preparing an epoxide in which the titanium-based catalyst is used.
    BACKGROUND OF THE INVENTION
    Titanium-based catalysts are known to be useful in the preparation of epoxides from olefins using a hydroperoxide. Methods for preparing titanium-based catalysts active in epoxidation reactions are also known; titanium sites on silica surfaces are generally created by gas phase impregnation or by impregnation using organic solvents. EP 0345856 A discloses a process for making a titanium catalyst suitable for epoxidizing olefins using a hydroperoxide, wherein a solid silica and / or an inorganic silicate is impregnated with gaseous titanium tetrachloride. WO 2004/050233 A1 describes a method for preparing an epoxidation catalyst, which method comprises impregnating a silicon-containing support with a gas stream consisting of titanium halide.
    Other existing methods of preparing epoxidation catalysts include dissolving a titanium compound in an organic solvent for placement on a support. Such a process is described in, for example, US 6,187,934, which describes the use of alcohols, ketones, ethers or esters as a solvent, and US 6,011,162, which describes the use of non-oxygenated hydrocarbon solvents such as heptane.
    Both gas phase impregnation and impregnation using organic solvents have disadvantages.
    Both methods are difficult to implement on a large scale. Furthermore, titanium placement via gas-phase impregnation requires very expensive installations (due to inherent corrosion problems), while titanium placement via organic impregnation also involves burning away excess solvent, which can get the temperature out of control and releasing large amounts of CO2. These problems make the titanium placement step expensive and environmentally unfriendly. US 3,829,392 A discloses that the efficiency of olefin epoxidation catalysts comprising an inorganic oxygen compound of silicon in chemical combination with certain metal oxides or hydroxides is improved when such catalysts are treated before use by contacting them with an organic silylating agent at elevated temperatures to bring.
    One catalyst preparation method described in U.S. Pat. No. 3,829,392 A in column 2, line 70, column 3, line 4, is said to be impregnation of a silicon-containing support with a suitable metallic solution followed by heating, coking of the metal hydroxide and silica and by annealing together at elevated temperatures of a mixture of inorganic silica-containing solid and metal oxides. However, US 3,829,392 A points out that the catalyst preparation method for the functioning or effectiveness of the invention described therein is not essential.
    Example III in US 3,829,392 A describes the preparation of a silylated catalyst from silica gel and an aqueous solution of titanium tetrachloride and oxalic acid. After impregnation, the silica gel was dried and then annealed at 800 ° C to form a titania / silica product, which product was then subjected to silylation. EP 1,005,907 A1 describes a catalyst for the epoxidation of unsaturated hydrocarbons, said catalyst comprising finely divided gold particles immobilized on a titanium-containing oxide and subjected to silylation or a hydrophobizing treatment.
    Example 2 in EP 1,005,907 A1 discloses immersing silica in an aqueous solution of titanium bis-ammonium lactate dihydroxide. After distillation of excess water, the residue was dried and then calcined at 900 ° C to form a titanium / silica composite oxide (a titania silica product). Said titania silica product was then treated with an aqueous solution of chloro gold acid to produce after processing a catalyst comprising a titanium-containing oxide with ultrafine gold particles supported thereon.
    It will be appreciated that since the products produced in the aforementioned examples of US 3,829,329 A and EP 1,005,907 A1 are titania-silica products, the titanium therein exists in a fully octahedral geometry (coordination number 6).
    It is an object of the invention to provide an alternative process for preparing a titanium-based catalyst that exhibits good efficacy in epoxidation reactions and which has an answer to some or all of the above issues. It is particularly preferred to be able to provide such a catalyst that exhibits favorable performance even if there is a reduced titanium loading therein.
    Propositions of the invention
    According to a first aspect of the present invention, a method for preparing a titanium-based catalyst active in epoxidation reactions is provided, which method comprises the steps of: (a) impregnating a silica support with a liquid solution of a titanium compound in an inorganic solvent system under formation of an impregnated silica support carrying the solution of the titanium compound; (b) drying the impregnated silica support obtained in step (a); (c) annealing the product obtained in step (b) at a temperature of at most 750 ° C; and (d) silylating the product obtained in step (c) to form a titanium-based catalyst active in epoxidation reactions.
    This method provides a simple way to place titanium on a silica support by impregnation of soluble titanium compounds on the basis of an inorganic solvent (for example, water-based), which results in a rapid and efficient preparation method of a titanium-based catalyst active in epoxidation (hereinafter) also called a titanium-based catalyst, a titanium catalyst or an epoxidation catalyst) and wherein the catalyst thus obtained stores favorable titanium geometries, i.e., a substantial amount of tetrahedral Ti compound.
    The method according to the first aspect of the invention can be particularly suitable for rapidly producing a charge of epoxidation catalyst in an emergency, for example if a problem arises during the production of epoxidation catalyst via a more complicated gas-based method, because the new method can be used without the necessity installations intended for the purpose are used in a standard manufacturing system.
    The method according to the invention can be more environmentally friendly than the known methods; the inorganic solvent system ensures that no organic solvents need to be burned, which would result in the release of CO2. Furthermore, combustion of organic solvents can get the temperature out of control, which can damage the catalyst or even cause explosions or other safety problems.
    Step (a) involves impregnating a silica support with a liquid solution of a titanium compound in an inorganic solvent system to form an impregnated silica support carrying the solution of the titanium compound.
    The inorganic solvent system is inorganic in the sense that it comprises or consists of one or more inorganic solvents. Inorganic solvents are solvents that do not contain carbon.
    In one embodiment, the inorganic solvent system comprises water, sulfuric acid, ammonia or a combination thereof.
    In one embodiment, the inorganic solvent system comprises water, which means that the liquid solution is an aqueous solution. In one embodiment, the inorganic solvent system comprises water, optionally combined with sulfuric acid or ammonia. In one embodiment, water or an aqueous solution comprising sulfuric acid or ammonia forms at least 90% by weight, suitably at least 99% by weight, of the inorganic solvent system. In one embodiment, the inorganic solvent system consists of water, optionally combined with sulfuric acid or ammonia. In one embodiment, the inorganic solvent system comprises or consists of water and sulfuric acid.
    In one embodiment, the inorganic solvent system comprises at least 50% by weight of water, in particular at least 70% by weight of water.
    The titanium compound can in principle be any titanium compound that is soluble in the relevant inorganic solvent system. Suitably, it may, for example, be a water-soluble titanium compound.
    In one embodiment, the titanium compound is a titanium (IV) compound.
    In one embodiment, the titanium compound is a titanium complex that comprises one or more organic ligands. Examples of such ligands are, for example, a lactate or an oxalate ligand. In one embodiment, the titanium complex is in the form of a salt that can dissociate in water. The titanium complex can advantageously be in the form of an ammonium salt. In one embodiment, the titanium compound is titanium (IV) bis (ammonium lactate) dihydroxide.
    In a preferred embodiment, the titanium compound is titanium (IV) oxysulfate.
    The solution can be acidic, basic or neutral. Especially since the titanium compound can take various forms, a series of pH values can be used.
    In one embodiment, the solution is acidic. Acid solutions can have a number of advantages, such as improved solubility of the titanium compound, especially when the titanium compound is titanium (IV) oxysulfate. Furthermore, to improve titanium deposition on silica, silica can be treated with acidic solutions, which can remove impurities from the silica support so that side reactions during catalyst preparation or a subsequent epoxidation reaction are minimized. Impregnating a titanium compound using an acid solution (e.g., an acidic aqueous solution) can have a similar effect without the need for a prior acid treatment step, which can limit the required manufacturing steps while maintaining the qualities of the catalyst thus obtained. Thus, in one embodiment, the method excludes such a separate pre-treatment step.
    In one embodiment, the solution of the titanium compound has a pH of less than 5, less than 4, less than 3 or less than 2. In one embodiment, the solution of the titanium compound has a pH of 1-5, 1-4, 1- 3, or 1-2, especially when the titanium compound is titanium (IV) oxysulfate.
    In one embodiment, the solution of the titanium compound has a pH of 6-9, for example 6-8, 7-9, or 7-8, particularly when the titanium compound is a titanium complex comprising one or more organic ligands, such as, for example, titanium (IV) bis (ammonium lactate) dihydroxide.
    The amount of titanium required in the solution of the titanium compound can be calculated by those skilled in the art using routine laboratory techniques depending on the desired weight percentage of titanium in the final catalyst (see Examples 1 and 2).
    In one embodiment, the weight percentage of titanium in the solution of the titanium compound is 0.1-10% by weight, for example 1-5% by weight.
    The silica support may essentially consist of (optionally water-containing) silica. However, there may also be limited amounts of further compounds, e.g., impurities, which may affect the performance of the final catalyst. In one embodiment, the silica carrier used in the present invention comprises at most 1200 ppm sodium or at most 1000 ppm sodium. In one embodiment, the silica support comprises at most 500 ppm aluminum, at most 500 ppm calcium, at most 200 ppm potassium, at most 100 ppm magnesium and / or at most 100 ppm iron. The amounts are based on the amount of carrier.
    In one embodiment, the silica support is a silica gel. The silica gel carrier can be any carrier derived from a silicon-containing gel. In general, silica gels are a solid, amorphous form of hydrous silica that are distinguished from other hydrous silicas by their microporosity and hydroxylated surface. Silica gels usually contain three-dimensional networks of aggregated silica particles with colloidal dimensions. They are usually prepared by acidifying an aqueous sodium silicate solution by combining it with a strong mineral acid. The acidification causes the formation of monosilicic acid (Si (OH) 4), which polymerizes into particles with internal siloxane couplings and external silanol groups. The polymer particles therefore aggregate and form chains and ultimately gel networks. Silicate concentration, temperature, pH and addition of coagulants influence the gel time and the final gel characteristics such as density, strength, hardness, surface area (SA) and pore volume (PV). The hydrogel thus obtained is usually stripped of electrolytes, dried and activated by washing. Examples of suitable silica gel carriers are the silica carriers available under the trade names "V432" and "DAVICAT P-732" from Grace Davison.
    In one embodiment, the silica support may be a shaped extrudate of silica powder, for example as described in WO 01/97967. Formed silica powder extrudates differ from silica gel carriers in their manufacturing method and their physical properties. The high mechanical energy required for the formation of the extrudate gives the extrudate a high breaking strength and density, but can lower the pore volume. A drawback of extrudates is that several steps are required to obtain extrudates of suitable strength.
    In one embodiment, the silica support has a weight average particle size of at most 2.5 mm, at most 2.3 mm, at most 2.0 mm, at most 1.8 mm, at most 1.6 mm or at most 1.4 mm. In one embodiment, the weight average particle size is at least 0.2 mm, at least 0.4 mm, or at least 0.6 mm. In one embodiment, the weight average particle size is 0.2-2.5 mm, 0.4-2.5 mm, 0.6-2.5 mm, 0.2-2.3 mm, 0.4-2.3 mm, 0.6-2.3 mm, 0.2-2.0 mm, 0.4-2.0 mm, 0.6-2.0 mm, 0.2-1.8 mm, 0.4 -1.8 mm, 0.6-1.8 mm, 0.2-1.6 mm, 0.4-1.6 mm, 0.6-1.6 mm, 0.2-1.4 mm , 0.4-1.4 mm, or 0.6-1.4 mm. In one embodiment, the weight average particle size is approximately 1.3 mm.
    In one embodiment, the silica support has a surface area (SA) of at least 190 m2 / g, at least 200 m2 / g, at least 250 m2 / g, or at least 300 m2 / g. In one embodiment, the silica support has a surface area of at most 1000 m2 / g, at most 800 m2 / g or at most 500 m2 / g. In one embodiment, the surface area is 190-1000 m2 / g, 200-1000 m2 / g, 250-1000 m2 / g, 300-1000 m2 / g, 190-800 m2 / g, 200-800 m2 / g, 250- 800 m2 / g, 300-800 m2 / g, 190-500 m2 / g, 200-500 m2 / g, 250-500 m2 / g or 300-500 m2 / g. In one embodiment, the surface area is approximately 330 m2 / g.
    In one embodiment, the silica support has a pore volume (PV) of 0.8-1.3 cm 3 / g. In one embodiment, the silica support has a pore volume (PV) of 0.9-1.3 cm 3 / g, 1.0-1.3 cm 3 / g, 1.1-1.3 cm 3 / g, 0.8-1 , 2 cm 3 / g, 0.9-1.2 cm 3 / g, 1.0-1.2 cm 3 / g or 1.1-1.2 cm 3 / g. In one embodiment, the pore volume is approximately 1.15 cm 3 / g.
    In one embodiment, step (a) is performed using pore volume impregnation methods. These impregnation methods include adding solution to a dry support in an amount based on the pore volume of the support. Examples of these types of impregnation methods include pore volume impregnation, dry impregnation, incipient wetness impregnation and capillary impregnation. The techniques are known and are based on dissolving the active ingredient or its precursor in a solution and adding this solution to a carrier, the capillary action of which draws the solution into the pores of the carrier. The amount of the added solution is lower or at most equal to the pore volume of the support. Further information can be found in "MANUAL OF METHODS AND PROCEDURES FOR CATALYST CHARACTERIZATION" by J. HABER, J.H. BLOCK and B. DELMON, Pure & Appl. Chem. Vol. 67, Nos. 8/9, pp. 1257-1306, 1995 (IUPAC).
    The use of pore volume impregnation helps to ensure efficient use of titanium since only the amount of titanium that is desired to be present on the final catalyst needs to be dissolved in the appropriate amount of solvent, after which the entire solution obtained is impregnated onto the silica support. This is illustrated in Examples 1 and 2.
    In one embodiment, step (a) is carried out using methods of the dynamic impregnation type, such as, for example, circulating solution impregnation. This method involves the circulation of a solution through a carrier bed.
    In one embodiment, the method according to the first aspect of the invention comprises a further step prior to step (a), wherein the silica carrier is dried. In one embodiment, the drying method comprises subjecting the silica support to a temperature of 100-400 ° C, such as, for example, 200-400 ° C. In one embodiment, drying is carried out for 1-8 hours. In one embodiment, drying is carried out in the presence of an inert gas such as nitrogen.
    Step (b) involves drying of the impregnated silica carrier obtained in step (a). In one embodiment, step (b) comprises subjecting the impregnated silica support obtained in step (a) to a temperature of 100-400 ° C, such as, for example, 200-400 ° C, 100-300 ° C, 200-300 ° C , 100-300 ° C or 100-200 ° C.
    Step (c) involves annealing of the product obtained in step (b). The annealing step can fix the titanium on the surface of the silica support and can destroy any non-titanium components of the titanium compound present on the support.
    In one embodiment, annealing of the impregnated support in step (c) is performed by subjecting the product obtained in step (b) to a temperature of at least 500 ° C, at least 550 ° C, at least 600 ° C, at at least 650 ° C or at least 700 ° C.
    In preferred embodiments, the annealing is carried out at a temperature of at most 600 ° C, at most 650 ° C or at most 700 ° C.
    In one embodiment, the annealing is performed at a temperature of 500-750 ° C, 550-750 ° C, 600-750 C, 650-750 C, 700-750 ° C, 500-700 ° C, 550-700 ° C, 600-700 ° C, 650-700 ° C, 500-650 ° C, 550-650 ° C, 600-650 ° C or 500-600 ° C.
    In one embodiment, annealing is carried out at a temperature of about 550 ° C, especially when the titanium compound is a titanium complex comprising one or more organic ligands, such as titanium (IV) bis (ammonium lactate) dihydroxide.
    In one embodiment, the annealing is performed at a temperature of about 750 ° C, especially when the titanium compound is titanium (IV) oxysulfate.
    Step (d) involves silylation of the product obtained in step (c) to form a titanium-based catalyst active in epoxidation reactions. This can be done by contacting the product obtained in step (c) with a silylating agent.
    In one embodiment, contacting the product obtained in step (c) with a silylating agent can be carried out at elevated temperature, for example at least 100 ° C or at least 150 ° C, for example at a temperature of 100-500 ° C, 100 ° C 450 ° C, 100-400 ° C, 100-350 ° C, 100-300 ° C, 100-250 ° C, 100-200 ° C, 150-500 ° C, 150-450 ° C, 150-400 ° C, 150-350 ° C, 150-300 ° C, 150-250 ° C or 150-2000C. In one embodiment, it is approximately 185 ° C.
    Examples of silylating agents that can be used in step (d) include organosilanes, such as, for example, tetra-substituted silanes with C 1 -C 3 hydrocarbyl substituents. In one embodiment, the silylating agent is hexamethyldisilazane (HMDS). Examples of specific, suitable silylation methods and agents are described in, for example, US 3,829,392 A and US 3,923,843 A.
    According to a second aspect of the present invention, a titanium-based catalyst active in epoxidation is provided which can be obtained by the process according to the first aspect of the invention.
    The catalyst produced by the process according to the first aspect of the invention differs in structure from known titanium-based catalysts, as evidenced by observed differences in properties (see Tables 2 and 3 in the Example section).
    In one embodiment, the weight percentage of titanium present in the catalyst (based on total catalyst weight) is in the range of 0.1-10% by weight, for example 0.1-5% by weight, 0.1-4% by weight , 0.1-3% by weight, 1-10% by weight, 1-5% by weight, 1-4% by weight, 1-3% by weight, 1.5-10% by weight, 1.5 -5% by weight, 1.5-4% by weight, 1.5-3% by weight, 2-10% by weight, 2-5% by weight, 2-4% by weight, 2-3% by weight. %, 3-10% by weight, 3-5% by weight or 3-4% by weight.
    In one embodiment, titanium is the only metal present in the catalyst.
    In one embodiment, the weight percentage of titanium in the catalyst is about 4% by weight, especially when the catalyst is obtained using titanium (IV) bis (ammonium lactate) dihydroxide as a titanium compound in the method according to the first aspect of the invention.
    In one embodiment, the weight percentage of titanium in the catalyst is 2-3% by weight, especially when the catalyst is obtained using titanium (IV) oxysulphate as the titanium compound in the method according to the first aspect of the invention.
    In a preferred embodiment of the present invention, when the catalyst is obtained using titanium (IV) oxysulphate as the titanium compound by the method according to the first aspect of the invention, the weight percentage of titanium in the final catalyst is about 2% by weight.
    According to a third aspect of the present invention, there is provided a method for preparing an epoxide, which method comprises contacting a hydroperoxide and an olefin with a titanium-based catalyst prepared in accordance with the method according to the first aspect of the invention, and withdrawing a product stream comprising an epoxide and an alcohol and / or water.
    As mentioned above, the production of epoxides by epoxidation of the corresponding olefin using a hydroperoxide as a source of oxygen is known in the art.
    In one embodiment, the olefin is propylene and the epoxide formed is propylene oxide.
    The hydroperoxide can be, for example, hydrogen peroxide or an organic hydroperoxide. In one embodiment, the hydroperoxide is ethylbenzene hydroperoxide, tert-butyl hydroperoxide or cumene hydroperoxide.
    In one embodiment, the hydroperoxide is ethylbenzene hydroperoxide and the alcohol formed is 1-phenylethanol.
    In one embodiment, the method further comprises dehydrating 1-phenylethanol to form styrene.
    In one embodiment, the hydroperoxide is tert-butyl hydroperoxide, which forms tert-butanol. In one embodiment, in the process according to the third aspect of the invention, tert-butyl hydroperoxide is reacted with propylene to form tert-butanol and propylene oxide. In one embodiment, tert-butanol is then etherified to methyl tert-butyl ether (MTBE).
    In one embodiment, the hydroperoxide is cumene hydroperoxide, which can optionally be formed by reacting cumene with oxygen or air. In one embodiment, in the process according to the third aspect of the invention, cumene hydroperoxide is reacted with propylene to form 2-phenylpropanol and propylene oxide.
    The conditions for the method for preparing an epoxide according to the third aspect of the present invention are those conventionally used. For propylene epoxidation reactions using ethylbenzene hydroperoxide, typical reaction conditions include temperatures of 50-140 ° C, for example 70-120 ° C, and pressure values of up to 80 bar, the reaction medium being in the liquid phase.
    The invention is further illustrated by the following Examples.
    Examples
    Experimental Methods Pore Volume and Surface
    Pore volume is measured together with surface area, using the same method, namely ASTM D4567-03 (2008): Standard Test Method for Single-Point Determination or Specific Surface Area or Catalysts and Catalyst Carriers Using Nitrogen Adsorption by Continuous Flow Method.
    Particle size
    The particle size distributions were determined using the Camsizer (Retsche technology Laser Optik Systeme, Germany). Accordingly, all of the particle sizes mentioned herein are particle sizes based on volume, such as obtained by dynamic image analysis.
    Example 1 - Synthesis of Catalyst A
    A reference silica carrier (Grace P543 silica beads with nominal properties as listed in Table 1, below) was loaded with 4% by weight of Ti using titanium (IV) bis (ammonium lactate) dihydroxide as the titanium source.
    The impregnation solution was obtained by starting from a commercially available starting solution of titanium (IV) bis (ammonium lactate) dihydroxide in water. This starting solution was analyzed with ICP (Inductively Coupled Plasma Spectroscopy) and was found to contain 7.6% by weight of titanium.
    To obtain an impregnation solution, the starting solution was diluted with an appropriate amount of water. To impregnate 150 grams of support, the impregnation solution was obtained by starting from 78.98 grams of the starting solution of titanium (IV) bis (ammonium lactate) dihydroxide containing 6 grams of titanium, and adding water to a total volume of 180 ml.
    The entire clear solution obtained was then impregnated by pore volume impregnation on 150 grams of freshly dried support.
    The support was rolled for about 1 hour and the next step was to dry the impregnated support with a dryer at 120 ° C for 1 hour under atmospheric pressure.
    Annealing of the material thus obtained was done at 550 ° C for 105 minutes.
    Gas phase silylation of the resulting product was performed in an automated test stand unit. Preheated hexamethyldisilazane gas (HMDS gas) was passed through a purge stream of 1.4 Nl / h nitrogen gas over 75 grams of the product obtained from the annealing step at 185 ° C. The boiling point of HMDS is 126 ° C. HMDS was dosed at a rate of 18 g / h. The exothermic silylation reaction was monitored with four thermocouples placed at different heights in the catalyst bed. A temperature rise of 25 ° C was then observed for all thermocouples within 30 minutes. The HMDS dose was discontinued after 2 hours. Excess HMDS was stripped for 3 hours at 3 Nl / hr at 185 ° C. Excess HMDS and ammonia as a by-product were vented with the nitrogen stream and the ammonia was neutralized in a NaOH scrubber. After cooling to room temperature, 78.2 grams of Catalyst A was obtained.
    Table 1. Nominal Properties of the Reference Silicadraqer, Grace P543 Silica
    Area (SA) 330 m2 / g
    Pore volume (PV) 1.15 cm 3 / g
    Particle size Distribution: 0.6-2.0 mm
    Average particle size: 1.3 mm Porosity such as 68.6% measured with Hg intrusion
    Impurities none
    Example 2 - Synthesis of Catalyst B
    The same silica support as the one used in Example 1 was loaded with 2 wt% Ti using titanium oxysulfate as the titanium source.
    The impregnation solution was obtained by starting from a commercially available starting solution of titanium oxysulphate in dilute sulfuric acid. This starting solution was analyzed with ICP and was found to contain 4.6% by weight of titanium.
    To obtain an impregnation solution, the starting solution was diluted with the appropriate amount of water. For impregnation of 150 g of support, the impregnation solution was obtained by starting from 22.78 g of titanium oxysulphate as the starting solution, containing 3 g of titanium, and adding water to a total volume of 180 ml.
    The entire clear solution obtained was then impregnated by pore volume impregnation on 150 grams of freshly dried support.
    The support was rolled for about 1 hour and the next step was to dry the impregnated support with a dryer at 120 ° C for 1 hour under atmospheric pressure.
    Annealing of the material thus obtained was done at 750 ° C for 2 hours.
    Gas phase silylation was carried out on 75 grams of the product obtained in the same manner as described in Example 1, yielding 78.2 grams of Catalyst B.
    Example 3 (for comparison) - Synthesis of Comparison catalyst C
    Comparative catalyst C was prepared by loading the same 5j-ica support as used in Examples 1 and 2 with 4 wt% Ti, according to the known general teachings of EP 0345856 A using gas phase impregnation of titanium tetrachloride on a silica support, followed by annealing at 600 ° C and hydrolysis.
    This was followed by gas phase silylation in the same manner as described in Examples 1 and 2 of 75 grams of the product obtained.
    Example 4 - Comparison of Catalysts A, B and C in the epoxidation of 1-octene
    In the 1-octene loading test, 50 ml of a mixture containing 7.5% by weight of ethylbenzene hydroperoxide (EBHP) and 36% by weight of 1-octene in ethylbenzene (EB) was reacted with 1 g of epoxidation catalyst at 40 ° C with thorough mixing.
    After 1 hour, the flask with the reaction mixture was cooled in ice / water to terminate the reaction and the reaction product was analyzed by titration, spectroscopically or by GC. The titration was performed shortly after the end of the test, because the reaction continues at a slower pace.
    As can be seen from Table 2 below, Catalysts A and B produced in accordance with the invention have an acceptable level of selectivity with respect to Comparative Catalyst C, which was produced using gas phase impregnation.
    Table 2. Performance data of various Ti-based catalysts active in epoxidation reactions
    Ti Efficacy OO / EBHP content per Ti selectivity (wt%) site (mole (%) EBHP / mole Ti)
    Catalyst A 4 1.07 83.44
    Catalyst B 2 2.62 86.40
    Comparison 4 3.51 93.8
    catalyst C
    Catalyst B (which contained 2 wt.% Ti and was prepared using titanium oxysulphate) is particularly advantageous because it allows placement of up to 50% lower Ti loads (e.g., 2 wt% instead of 4 wt%) while acceptable selectivity is maintained, which can further reduce the release of harmful gases such as SO 2 and lower the required volumes of acid solutions of Ti salts. Compared to comparative catalyst C, which was produced using gas phase impregnation of titanium tetrachloride, this also eliminates formation of corrosive HCl gases, which are highly corrosive, especially in combination with high temperature.
    Example 5 - Comparison of Catalysts A, B and C for epoxidation of propylene
    The epoxidation reaction of propylene was carried out with EBHP / EB as feed and propylene at a pressure of 40 bar. The experiment is performed at a WHSV of 16.0 g / gh. About 0.4 g of milled and sieved catalyst was charged into the reactor tube. The reaction temperature was kept constant at 70 DEG C. for 222 hours.
    As can be seen from Table 3 below, Catalysts A and B produced in accordance with the invention also have an acceptable level of selectivity with respect to Comparative Catalyst C, which was produced using gas phase impregnation.
    Table 3. Performance data of various Ti-based catalysts active in epoxidation reactions
    Ti content Efficacy PO / EBHP- (wt%) per Ti-site selectivity (mol EBHP / mol (%)
    Ti)
    Catalyst A 4 1.84
    Unsilylated
    Catalyst B 2 3.84 98.0
    Comparison 4 6.24 99.0
    catalyst C
    As can also be seen in Example 4, in Example 5, Catalyst B (which contains 2% by weight of Ti and is prepared using titanium oxysulphate) is again particularly advantageous because it allows placement of up to 50% lower Ti loads ( for example 2% by weight instead of 4% by weight) while maintaining acceptable selectivity, which can further reduce the release of harmful gases such as SO 2 and lower the required volumes of acid solutions of Ti salts. Compared to comparative catalyst C, which was produced using gas phase impregnation of titanium tetrachloride, this also eliminates formation of corrosive HCl gases, which are highly corrosive, especially in combination with high temperature.
    Example 6 - Structure comparison of Catalyst precursors
    Unsilylated catalyst precursors D and E were prepared according to the general procedures of Example 2 and Comparative Example 3, respectively, but without the final silylation step.
    UV-VlS spectra were recorded for each of the unsilylated catalyst precursors. These spectra can provide information about the geometries of the Ti centers present on the catalyst. Ti centers in tetrahedral geometry in particular result in a band around 210 nm, while Ti centers in octahedral geometry result in a band around 235 nm.
    For each of the unsilylated catalyst precursors, the relative intensity of the bands at these wavelengths was measured to get an indication of the proportion of the different Ti geometries present in these catalyst precursors.
    This data is presented in Table 4 below in the form of the ratios between the band intensity at 210 and 235 nm.
    Table 4.
    Catalyst precursor Ratio 210/235 nm D (in accordance with Ex. 2) 0.21 E (in accordance with Comp. Ex. 3) 0.73
    As can be seen from these data, catalyst precursor D (prepared according to the general procedures of Example 2 of the invention) has a lower 210 nm: 235 nm ratio, i.e., relatively fewer tetrahedral Ti centers and relatively more octahedral Ti centers , then catalyst precursor E (prepared according to Comparative Example 3).
    Catalyst precursor E is made by a chemical vapor deposition method which, by its nature, yields a high number of tetrahedral Ti sites.
    While Catalyst Precursor D has a lower number of tetrahedral Ti sites than Catalyst Precursor E, which is produced by gas phase impregnation of titanium tetrachloride on a silica support, as opposed to the titania silica catalysts prepared in US 3,829,329 A and EP 1,005,907 A1. however, it is clear that the manufacturing procedure of the present invention allows significant retention of highly effective tetrahedral compounds.
    权利要求:
    Claims (15)
    [1]
    A process for preparing a titanium-based catalyst active in epoxidation reactions, the process comprising the steps of: (a) impregnating a silica support with a liquid solution of a titanium compound in an inorganic solvent system to form an impregnated silica support comprising the solution of carries the titanium compound; (b) drying the impregnated silica support obtained in step (a); (c) annealing the product obtained in step (b) at a temperature of at most 750 ° C; and (d) silylating the product obtained in step (c) to form a titanium-based catalyst active in epoxidation reactions.
    [2]
    The method of claim 1, wherein the inorganic solvent system comprises water.
    [3]
    The method of claim 2, wherein the inorganic solvent system comprises water combined with sulfuric acid or ammonia.
    [4]
    The method of any one of the preceding claims, wherein the titanium compound is a titanium (IV) compound.
    [5]
    The method of any one of the preceding claims, wherein the titanium compound is a titanium complex comprising one or more organic ligands.
    [6]
    The method of claim 5, wherein the titanium compound is titanium (IV) bis (ammonium lactate) dihydroxide.
    [7]
    The method of any one of claims 1-4, wherein the titanium compound is titanium (IV) oxysulfate.
    [8]
    The method of any one of claims 1-6, wherein the solution of the titanium compound has a pH of 6-9.
    [9]
    The method of any one of claims 1-4 or 7, wherein the solution of the titanium compound has a pH of less than 5.
    [10]
    The method of any one of the preceding claims, wherein step (a) is performed by pore volume impregnation.
    [11]
    A titanium-based catalyst effective in epoxidation which can be obtained with the process according to any one of the preceding claims.
    [12]
    A process for preparing an epoxide, which process comprises contacting a hydroperoxide and an olefin with a titanium-based catalyst prepared in accordance with the process of any one of claims 1-10, and withdrawing a product stream comprising an epoxide and an alcohol and / or water.
    [13]
    The method of claim 12, wherein the olefin is propylene and the epoxide is propylene oxide.
    [14]
    The method according to claim 12 or 13, wherein the hydroperoxide is ethylbenzene hydroperoxide and the alcohol is 1-phenylethanol.
    [15]
    The method of claim 14, wherein the method further comprises dehydrating 1-phenylethanol to form styrene.
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    同族专利:
    公开号 | 公开日
    NL2014073B1|2016-08-31|
    US20150182959A1|2015-07-02|
    CN104741150A|2015-07-01|
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    法律状态:
    2018-08-08| MM| Lapsed because of non-payment of the annual fee|Effective date: 20180101 |
    优先权:
    申请号 | 申请日 | 专利标题
    EP13199854|2013-12-30|
    EP13199854|2013-12-30|
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