Methods of etherification

Abstract

To provide methods of etherification.SOLUTION: Embodiments of the present disclosure are directed towards methods of etherification including modifying a zeolite catalyst with silica to provide a silica modified zeolite catalyst; and contacting the silica modified zeolite catalyst with an olefin and an alcohol to produce a monoalkyl ether.SELECTED DRAWING: None

Description

[Technical field]

[0001] Embodiments of the present disclosure relate to a process for etherification, and more specifically, the embodiments relate to a process for etherification that includes modifying a zeolite catalyst with silica to provide a silica-modified zeolite catalyst, and producing a mono-alkyl ether by contacting the silica-modified zeolite catalyst with an olefin and an alcohol. [Background technology]

[0002] Monoalkyl ethers are useful in many applications, such as, for example, solvents, surfactants, and chemical intermediates. There continues to be a focus in industry to develop new and improved materials and / or methods that can be utilized to produce monoalkyl ethers. Summary of the Invention

[0003] The present disclosure provides a method for etherification, the method including modifying a zeolite catalyst with silica to provide a silica-modified zeolite catalyst having a silica loading of 15 to 50 weight percent based on the total weight of the silica-modified zeolite catalyst, and producing a mono-alkyl ether by contacting the silica-modified zeolite catalyst with an olefin and an alcohol.

[0004] The above summary of the present disclosure is not intended to describe each disclosed embodiment or every implementation of the present disclosure. More specifically, the present specification illustrates exemplary embodiments. In several places throughout the application, guidance is provided through lists of examples, which examples can be used in various combinations. In each instance, the recited list serves only as a representative group and should not be interpreted as an exclusive list. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0005] Disclosed herein is a method for etherification that includes modifying a zeolite catalyst with silica to provide a silica-modified zeolite catalyst, and producing a mono-alkyl ether by contacting the silica-modified zeolite catalyst with an olefin and an alcohol.

[0006] Advantageously, the etherification method disclosed herein can provide improved, i.e., higher, mono-alkyl ether selectivity compared to etherification that does not utilize a silica-modified zeolite catalyst, as further discussed herein. Improved mono-alkyl ether selectivity may be desirable for many applications, such as providing chemical intermediates. As an example, mono-alkyl ethers can be utilized in the production of surfactants by ethoxylation processes, where mono-alkyl ethers can have a desirable effect on the surfactant properties, compared to, for example, di-alkyl ethers, which may have an undesirable effect on the surfactant properties.

[0007] Additionally, the etherification methods disclosed herein can provide improved, i.e., less dialkyl ether selectivity, as compared to etherification that does not utilize a silica-modified zeolite catalyst, as further discussed herein. Improved dialkyl ether selectivity can be desirable for many applications, such as the production of surfactants by ethoxylation processes, where dialkyl ethers can have undesirable effects on surfactant properties, as compared to, for example, monoalkyl ethers.

[0008] Zeolite catalysts are crystalline metallosilicates, e.g., aluminosilicates, composed of repeating tetrahedral units of, e.g., TO4, where T can be Si, Al, or P (or a combination of tetrahedral units). These units link together to form a framework with regular intracrystalline cavities and / or channels of molecular dimensions, e.g., micropores.

[0009] The embodiment of the present disclosure provides that the zeolite catalyst is a synthetic zeolite catalyst. The synthetic zeolite catalyst can be produced, for example, by the known process of crystallization of silica-alumina gel in the presence of an alkali and a template. Examples include zeolite beta catalyst (BEA), Linde type A (LTA), Linde type X and Y (Al-rich and Si-rich FAU), silicalite-1, ZSM-5 (MFI), Linde type B (zeolite P), Linde type F (EDI), Linde type L (LTL), Linde type W (MER), and SSZ-32 (MTT), which are described using IUPAC codes according to the nomenclature by the Structure Committee of the International Zeolite Association. The IUPAC codes describing the crystal structures depicted by the Structure Committee of the International Zeolite Association refer to the latest designations as of the priority date of this document, unless otherwise indicated.

[0010] One or more embodiments provide a zeolite catalyst, a zeolite beta (BEA) catalyst. One or more embodiments provide that the zeolite catalyst contains many Bronsted acid sites, i.e., sites that donate protons.

[0011] The zeolite catalyst can have a SiO2 / Al2O3 molar ratio of 5:1 to 1500:1 as measured using neutron activation analysis, including all individual values ​​and subranges from 5:1 to 1500:1, for example, the zeolite catalyst can have a SiO2 / Al2O3 molar ratio from a lower limit of 5:1, 10:1, 15:1, or 20:1 to an upper limit of 1500:1, 750:1, 300:1, or 100:1.

[0012] The zeolite catalyst can have an average pore diameter of 5 to 12 angstroms, including all individual values ​​and subranges between 5 and 12 angstroms, for example, the zeolite catalyst can have an average pore diameter from a lower limit of 5 or 7 angstroms to an upper limit of 11 or 12 angstroms.

[0013] Zeolite catalyst is 130~1000m 2 / g surface area of ​​130 to 1000 m 2 All individual values ​​and subranges of / g are included, for example, zeolite catalysts may have lower limits of 130, 150, 175, 300, 400 or 500 m / g. 2 / g~upper limit 1000, 900 or 800m 2 The surface area is measured according to ASTM D4365-19.

[0014] As mentioned above, the zeolite catalyst can be produced by a process that utilizes a template, which may also be referred to as an organic template. The template may also be referred to as a templating agent and / or structure directing agent (SDA). The template may be added to a reaction mixture for producing the zeolite catalyst to, for example, induce, e.g., direct, the molecular shape and / or pattern of the framework of the zeolite catalyst. Upon completion of the zeolite catalyst production process, the zeolite catalyst comprises a template, e.g., a template located in the micropores of the zeolite catalyst. The template is utilized in the formation of the zeolite catalyst. One or more embodiments provide that the template comprises ammonium ions. The template-containing zeolite catalyst can be produced by known processes. The template-containing zeolite catalyst can be commercially available. Examples of suitable commercially available metallosilicate catalysts include CP814E, CP814C, CP811C-300, CBV712, CBV720, CBV760, CBV2314, CBV10A from ZEOLYST INTERNATIONAL™ of Conshohocken, PA.

[0015] A variety of templates are known that can be utilized to prepare zeolite catalysts. Examples of templates include tetraethylammonium hydroxide, N,N,N-trimethyl-1-adamante-ammonium hydroxide, hexamethyleneimine, and dibenzylmethylammonium, among others.

[0016] The embodiments of the present disclosure provide for modifying a zeolite catalyst with silica to provide a silica-modified zeolite catalyst. The modification of the zeolite catalyst can be carried out through many known processes, such as, for example, impregnation or solution processes, followed by calcination. The modification of the zeolite catalyst with silica can utilize known conditions and can utilize known equipment and known ingredients. For example, the zeolite catalyst can be contacted with an organic solvent and / or aqueous solution containing a silicon compound. Examples of organic solvents include, but are not limited to, hexane, toluene, and combinations thereof. Examples of silicon compounds include, but are not limited to, tetramethyl orthosilicate, tetraethyl orthosilicate, and combinations thereof. The modification of the zeolite catalyst provides for the zeolite catalyst to be loaded with silica from the silicon compound.

[0017] The modification of the zeolite catalyst with silica may include contacting the zeolite catalyst with a solution containing a silicon compound, followed by calcination. The solution may include water and / or an organic solvent. Different amounts of silicon compounds and / or water and / or organic solvents may be utilized for different applications.

[0018] The zeolite catalyst can be contacted with the solution containing the silica compound at a temperature of, for example, 5° C. to 90° C. All individual values ​​and subranges between 5° C. and 90° C. are included, for example, the zeolite catalyst can be contacted with the solution containing the silica compound at a temperature from a lower limit of 5, 10, or 15° C. to an upper limit of 90, 85, or 80° C.

[0019] The zeolite catalyst can be contacted with the solution containing the silica compound for, for example, 0.5 hours to 96 hours, including all individual values ​​and subranges from 0.5 hours to 96 hours, for example, the zeolite catalyst can be contacted with the solution containing the silica compound for a lower limit of 0.5, 0.8, or 1 hour to an upper limit of 96, 72, 48, 24, or 12 hours.

[0020] One or more embodiments of the present disclosure provide that, as discussed above, many steps of modifying a zeolite catalyst can be repeated. For example, a zeolite catalyst can be contacted with a solution containing a silica compound multiple times. When a step of modifying a zeolite catalyst is repeated, the next step can utilize the same conditions and / or ingredients as the previous step. When a step of modifying a zeolite catalyst is repeated, the next step can utilize different conditions and / or ingredients than the previous step.

[0021] The silica modified zeolite catalyst has a silica loading of 15 to 50 weight percent based on the total weight of the silica modified zeolite catalyst. In other words, silica is added to the silica modified zeolite catalyst by modifying the zeolite catalyst with a silicon compound followed by calcination. All individual values ​​and subranges from 15 to 50 weight percent are included, for example, the zeolite catalyst can have a silica loading of a lower limit of 15, 20, 20.5, 21 or 21.5 weight percent to an upper limit of 50, 45, 40, 39 or 38 weight percent based on the total weight of the silica modified zeolite catalyst. The silica loading is determined by known processes. The silica loading is calculated based on the components utilized to produce the silica modified zeolite catalyst. For example, the silicon and aluminum loading of the silica modified zeolite beta catalyst is determined by elemental analysis (neutron activation analysis), for example, utilizing a known amount of aluminum of the zeolite catalyst based on the structure of the zeolite catalyst, and then calculating the silica loading of the silica modified zeolite catalyst.

[0022] One or more embodiments of the present disclosure provide that after contacting the zeolite catalyst with a silicon compound, the zeolite catalyst can be calcined to provide a silica-modified zeolite catalyst. The zeolite catalyst can be calcined at a temperature between 350°C and 700°C to provide a silica-modified zeolite catalyst. All individual values ​​and subranges between 350°C and 700°C are included, for example, the zeolite catalyst can be calcined at a lower limit of 350°C, 400°C, or 450°C to an upper limit of 700°C, 650°C, or 600°C.

[0023] The zeolite catalyst can be calcined in a number of known calcination environments, for example, the zeolite catalyst can be calcined in an air environment.

[0024] The zeolite catalyst may be calcined, i.e., exposed to a temperature of 350° C. to 700° C. in a calcination environment for a period of 1 hour to 24 hours. All individual values ​​and subranges from 1 hour to 24 hours are included, for example, the zeolite catalyst may be calcined from a lower limit of 1 hour, 3 hours, or 6 hours to an upper limit of 24 hours, 18 hours, or 12 hours.

[0025] One or more embodiments provide that the methods disclosed herein include reducing, e.g., removing, the template of the zeolite catalyst prior to modifying the zeolite catalyst with silica as discussed herein. An embodiment of the present disclosure provides that the template of the zeolite catalyst can be reduced by calcination.

[0026] To reduce the template, the zeolite catalyst can be calcined at a temperature between 550° C. and 750° C. All individual values ​​and subranges between 550° C. and 750° C. are included, for example, the zeolite catalyst can be calcined at a lower limit of 550° C., 560° C., or 575° C. to an upper limit of 750° C., 700° C., or 650° C. to reduce the template.

[0027] To reduce the template, the zeolite catalyst can be calcined in a number of known calcination environments, for example, the zeolite catalyst can be calcined in an air environment.

[0028] To reduce the template, the zeolite catalyst can be calcined, i.e., exposed to a temperature of 550° C. to 750° C. in a calcination environment for 1 hour to 24 hours. All individual values ​​and subranges from 1 hour to 24 hours are included, for example, the zeolite catalyst can be calcined from a lower limit of 1 hour, 3 hours, or 6 hours to an upper limit of 24 hours, 18 hours, or 12 hours.

[0029] The present disclosure relates to a method of etherification, which refers to a chemical process, e.g., a chemical reaction, that produces ethers. The method disclosed herein includes producing mono-alkyl ethers by contacting a silica-modified zeolite catalyst with an olefin and an alcohol.

[0030] As used herein, "olefin" refers to a compound that is a hydrocarbon having one or more carbon-carbon double bonds. Embodiments of the present disclosure provide that the olefin comprises 6 to 30 carbon atoms. All individual values ​​and subranges from 6 to 30 carbon atoms are included, for example, the olefin can have a lower limit of 6, 8, or 10 carbon atoms to an upper limit of 30, 20, or 14 carbon atoms.

[0031] The olefin may be an alpha (α) olefin, an internally disubstituted olefin, or a cyclic structure (e.g., C3-C 12 The olefins may include alkenes such as cycloalkene. Alpha olefins contain unsaturated bonds at the alpha position of the olefin. Suitable alpha olefins may be selected from the group consisting of propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-icosene, 1-docosene, and combinations thereof. Internal disubstituted olefins contain unsaturated bonds that are not at the terminal position of the olefin. The internal olefins may be selected from the group consisting of 2-butene, 2-pentene, 2-hexene, 3-hexene, 2-heptene, 3-heptene, 2-octene, 3-octene, 4-octene, 2-nonene, 3-nonene, 4-nonene, 2-decene, 3-decene, 4-decene, 5-decene, and combinations thereof. Other exemplary olefins may include butadiene and styrene.

[0032] Examples of suitable commercially available olefins include NEODENE™ 6-XHP, NEODENE™ 8, NEODENE™ 10, NEODENE™ 12, NEODENE™ 14, NEODENE™ 16, NEODENE™ 1214, NEODENE™ 1416, NEODENE™ 16148 from Shell, The Hague, Netherland.

[0033] The embodiments of the present disclosure provide that the alcohol may contain a single hydroxyl group, or may contain two hydroxyl groups, i.e., glycol, or may contain three hydroxyl groups. The alcohol may contain 1 or more carbons, or 2 or more, or 3 or more, or 4 or more, or 5 or more, or 6 or more, or 7 or more, or 8 or more, or 9 or more carbons, but at the same time may contain 10 or less carbons, or 9 or less, or 8 or less, or 7 or less, or 6 or less, or 5 or less, or 4 or less, or 3 or less, or 2 or less carbons. The alcohol may be selected from the group consisting of methanol, ethanol, monoethylene glycol, diethylene glycol, propylene glycol, triethylene glycol, polyethylene glycol, monopropylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, 1,3-propanediol, 1,2-butanediol, 2,3-butanediol, 1,4-butanediol, 1,6-hexanediol, 1,4-cyclohexanemethanediol, glycerol, and combinations thereof. One or more embodiments provide that the alcohol is selected from the group consisting of monoethylene glycol, diethylene glycol, glycerol, and combinations thereof. One or more embodiments provide that the alcohol is a (poly)alkylene glycol, such as monoethylene glycol, diethylene glycol, propylene glycol, or triethylene glycol. Examples of (poly)alkylene glycols include monoethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, monopropylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, 1,3-propanediol, 1,2-butanediol, 2,3-butanediol, 1,4-butanediol, 1,6-hexanediol, paraxylene glycol, glycerol, and 1,4-cyclohexanemethanediol. One or more embodiments provide that the (poly)alkylene glycol is monoethylene glycol.

[0034] An embodiment of the present disclosure provides reacting an alcohol with an olefin, e.g., contacting the alcohol with a silica-modified zeolite catalyst, at a molar ratio of the alcohol to the olefin of from 0.05:1 to 20:1, including all individual values ​​and subranges from 0.05:1 to 20:1, e.g., the alcohol and olefin can be reacted at a molar ratio of the alcohol to the olefin of from a lower limit of 0.05:1, 0.075:1, or 0.1:1 to an upper limit of 20:1, 18:1, or 15:1.

[0035] As previously mentioned, the method disclosed herein includes contacting a silica-modified zeolite catalyst with an olefin and an alcohol to produce a monoalkyl ether. The olefin and alcohol can be contacted with the silica-modified zeolite catalyst under known etherification conditions and can utilize known reactor equipment and known reaction components. For example, the olefin and alcohol can be contacted with the reduced template zeolite catalyst in a slurry reactor, a fixed bed reactor, or a fluidized bed reactor. The reactor can be operated in batch or continuous mode.

[0036] The silica-modified zeolite catalyst can be utilized in an amount, for example, from 1 wt. % to 50 wt. % of the silica-modified zeolite catalyst based on the total weight of the olefin, including all individual values ​​and subranges between 1 wt. % and 50 wt. %, for example, the silica-modified zeolite catalyst can be at a lower limit of 1 wt. %, 3 wt. % or 5 wt. % to an upper limit of 50 wt. %, 40 wt. % or 30 wt. % based on the total weight of the olefin.

[0037] The olefin and alcohol can be contacted with the silica-modified zeolite catalyst at a reaction temperature between 80° C. and 200° C. All individual values ​​and subranges between 80° C. and 200° C. are included, for example, the olefin and alcohol can be contacted with the silica-modified zeolite catalyst at a lower limit of 80° C., 90° C., or 100° C. to an upper limit of 200° C., 175° C., or 150° C.

[0038] The reaction pressure may vary for different applications, for example, the reaction pressure may be reduced, atmospheric, or elevated.

[0039] When the silica-modified zeolite catalyst is contacted with an olefin and an alcohol, a mono-alkyl ether is produced. A variety of mono-alkyl ethers can be produced for different applications, for example, by varying which olefin is utilized and / or by varying which alcohol is utilized. Advantageously, the etherification method disclosed herein can provide improved, i.e., higher, mono-alkyl ether selectivity compared to etherification that does not utilize a silica-modified zeolite catalyst, as described herein.

[0040] Additionally, the etherification methods disclosed herein can provide improved, i.e., less dialkyl ether selectivity, as compared to etherification that does not utilize a silica-modified zeolite catalyst as described herein. EXAMPLES

[0041] In the present examples, various terms and names for materials are used, including, for example:

[0042] Zeolite beta catalyst (CP 814E, CAS number 1318-02-1, SiO2 / Al2O3 molar ratio of 25:1, average pore size 6.7 Å, surface area 680 m 2 / g, all organic templates removed by commercial supplier prior to receipt, obtained from Zeolyst International); Zeolite Beta catalyst (CP 806EL, CAS number 1318-02-1, SiO2 / Al2O3 molar ratio of 25:1, average pore size in Angstroms, surface area of ​​177 m 2 / g, containing the resulting organic template, obtained from Zeolyst International).

[0043] Example 1 was carried out as follows. Zeolite beta catalyst was modified with silica as follows. Zeolite beta catalyst (CP 806EL, 60 grams) was added to hexane (800 mL) in a vessel (1 L). Tetraethyl orthosilicate (40 mL) was added to the contents of the vessel with stirring, and then the contents of the vessel were stirred at ambient conditions for 96 hours. The solvent was then removed by rotary evaporation, and the dried zeolite beta catalyst was calcined at 550° C. in an air environment for 8 hours. The resulting material was then added to hexane (800 mL) in a vessel (1 L). Tetraethyl orthosilicate (40 mL) was added to the contents of the vessel with stirring, and then the contents of the vessel were stirred at ambient conditions for 24 hours. The solvent was then removed by rotary evaporation, and the dried zeolite beta catalyst was calcined at 550° C. in an air environment for 8 hours, to obtain a silica-modified zeolite beta catalyst. The silicon and aluminum loadings of the silica modified zeolite beta catalyst were determined by elemental analysis (neutron activation analysis) and the silica modified zeolite beta catalyst had an additional silica loading of 37.5% based on the total weight of the silica modified zeolite beta catalyst.

[0044] Etherification was carried out as follows: Silica modified zeolite beta catalyst (0.75 grams) was added to a vial reactor (40 mL) equipped with a rare earth magnetic stir bar (part number: VP 772FN-13-13-150, V&P Scientific, Inc.), 1-dodecene (6.2 grams) and monoethylene glycol (6.7 grams) were added to the vial reactor, and the contents of the vial reactor were heated to 150° C. and stirred for 3 hours for etherification. The contents of the vial reactor were then analyzed by gas chromatography. Gas chromatography samples were prepared by adding the contents of the vial reactor (100 μL) to 10 mL of an internal standard solution (1 mL of hexadecane dissolved in 1 L of ethyl acetate) and then analyzed offline using an Agilent GC (7890). For analysis, dioxane, 1-dodecene (1-C 12 ) and its isomers (C 12), 2-dodecanol, diethylene glycol, monoalkyl ethers and their isomers, and dialkyl ethers and their isomers were included for product quantification to provide weight percentages of species of interest.

[0045] The dodecene-derived species were dodecyl-monoether (ME), dodecyl-diether (DE), and 2-dodacanol.

[0046] The total amount of dodecene includes 1-dodecene and all other C of non-1-dodecene. 12 isomers were included.

[0047] Total amount of dodecene derived species = moles monoether + 2 × moles diether + 2-dodecanol.

[0048] Dodecyl monoether (ME) selectivity (%) was calculated by dividing [total amount of ME] by [C 12 The percentage was determined as [total amount of species of origin] × 100%.

[0049] Dodecyl diether (DE) selectivity (%) was calculated as 2 × [total amount of DE] / [C 12 The percentage was determined as [total amount of species of origin] × 100%.

[0050] The olefin conversion rate (%) was calculated by [C 12 Total amount of seeds from origin] / [C 12 The total amount of dodecene derived from each species was determined as [total amount of species derived from each species + total amount of dodecene] × 100%.

[0051] The results are reported in Table 1.

[0052] Comparative Example A was carried out similarly to Example 1 with the modifications that the zeolite beta catalyst (CP 806EL) was not modified with silica, 0.35 grams of catalyst was utilized instead of 0.75 grams, and the etherification reaction was run for 1.5 hours instead of 3 hours. The catalyst loading and / or the etherification reaction time were adjusted so that Example 1 and Comparative Example A had similar olefin conversions. The results are reported in Table 1. [Table 1]

[0053] The data in Table 1 show that Example 1 had improved, ie, greater, monoalkyl ether selectivity compared to Comparative Example A.

[0054] The data in Table 1 show that Example 1 had improved, ie, less dialkyl ether selectivity, compared to Comparative Example A.

[0055] Example 2 was carried out as follows: Zeolite beta catalyst (CP 814E) was calcined at 550°C for 12 hours in air environment to convert the catalyst from NH4 form to H form, and then the catalyst was modified with silica as follows: Zeolite beta catalyst (41 grams) was impregnated with a solution containing hexane (80 mL) and tetraethyl orthosilicate (20 mL), and the components were stirred at 20°C for 5 minutes. The catalyst was then dried at 200°C for 1 hour in a box oven. The catalyst was then calcined at 550°C for 4 hours in air environment to obtain a silica-modified zeolite beta catalyst.

[0056] Etherification was carried out as follows: Silica-modified zeolite beta catalyst (0.75 grams) was added to a vial reactor (40 mL) equipped with a rare earth magnetic stir bar (part number: VP 772FN-13-13-150, V&P Scientific, Inc.), 1-dodecene (6.2 grams) and monoethylene glycol (6.7 grams) were added to the vial reactor, and the contents of the vial reactor were heated to 150° C. and stirred for 3 hours for etherification. The results are reported in Table 2.

[0057] Comparative Example B was carried out similarly to Example 2, except that the zeolite beta catalyst (CP 814E) was not modified with silica. The results are reported in Table 2. [Table 2]

[0058] The data in Table 2 show that Example 2 had improved, ie, greater, monoalkyl ether selectivity compared to Comparative Example B.

[0059] The data in Table 2 show that Example 1 had improved, ie, less dialkyl ether selectivity, compared to Comparative Example B.

[0060] Example 3 was carried out as follows: Zeolite beta catalyst (CP 814E) was calcined at 550°C for 12 hours in air environment to convert the catalyst from NH4 form to H form, and then the catalyst was modified with silica as follows: Zeolite beta catalyst (10 grams) and hexane (100 mL) were added to a vessel, then tetraethyl orthosilicate (16.5 grams) was added to the vessel, and the contents of the vessel were stirred at 20°C for 60 hours. The contents of the vessel were then centrifuged to obtain a solid, which was calcined at 550°C for 8 hours in air environment to obtain a silica-modified zeolite beta catalyst.

[0061] Etherification was carried out as follows: Silica-modified zeolite beta catalyst (0.75 grams) was added to a vial reactor (40 mL) equipped with a rare earth magnetic stir bar (part number: VP 772FN-13-13-150, V&P Scientific, Inc.), 1-dodecene (6.2 grams) and monoethylene glycol (6.7 grams) were added to the vial reactor, and the contents of the vial reactor were heated to 150° C. and stirred for 1 hour for etherification. The results are reported in Table 3.

[0062] Comparative Example C was carried out similarly to Example 3 with the changes that the zeolite beta catalyst (CP 814E) was not modified with silica, 0.35 grams of catalyst was utilized instead of 0.75 grams, and the etherification reaction was for 1 hour. The catalyst loading was adjusted so that Example 3 and Comparative Example C had similar olefin conversions (%). The results are reported in Table 3. [Table 3]

[0063] The data in Table 3 show that Example 3 had improved, ie, greater, monoalkyl ether selectivity compared to Comparative Example C.

[0064] The data in Table 3 show that Example 3 had improved, ie, less dialkyl ether selectivity, compared to Comparative Example C.

Claims

1. 1. A process for etherification, said process comprising: modifying the zeolite catalyst with silica to provide a silica-modified zeolite catalyst having a silica loading of 15 to 50 weight percent, based on the total weight of the silica-modified zeolite catalyst; and producing a monoalkyl ether by contacting the silica-modified zeolite catalyst with an olefin and an alcohol.

2. 2. The method of claim 1, wherein the zeolite catalyst is a zeolite beta catalyst.

3. A method according to any one of claims 1 to 3, comprising reducing the template of the zeolite catalyst before the modification.

4. 4. The method of claim 3, wherein the reduced template of the zeolite catalyst comprises calcining the zeolite catalyst.

5. 5. The process of claim 1, wherein the olefin contains from 6 to 30 carbon atoms.

6. The olefin is １２ -C １４ The method according to any one of claims 1 to 5, wherein the copolymer is an olefin.

7. The method of any one of claims 1 to 6, wherein the alcohol is selected from the group consisting of monoethylene glycol, diethylene glycol, glycerol, and combinations thereof.

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