Patent Description:
Monoalkyl ethers are useful for a number of applications such as solvents, surfactants, and chemical intermediates, for instance. There is continued focus in the industry on developing new and improved materials and/or methods that may be utilized for making monoalkyl ethers.

<CIT> discloses a catalyst which is an inorganic solid acid containing a Group <NUM> metal element, preferably a crystalline metallosilicate, for producing (poly)alkylene glycol monoalkyl ether, which has a long catalyst life even if it is regenerated, and a method for using the catalyst.

<CIT> discloses a process for producing a (poly)alkylene glycol monoalkyl ether with high selectivity and high yield, in which the (poly)alkylene glycol monoalkyl ether is produced by reacting an olefin and a (poly)alkylene glycol in the presence of a catalyst, wherein either: <NUM>. a crystalline metallosilicate is used as the catalyst, at least a portion of the used catalyst is regenerated, and the regenerated catalyst is recycled as the catalyst for the reaction; or <NUM>. the reaction between the olefin and the (poly)alkylene glycol is carried out in the presence of either or both of a (poly)alkylene glycol dialkyl ether and an alcohol.

<CIT> discloses a process for making glycerol di-tert-butyl ethers, in which glycerol and isobutylene are reacted in the presence of a beta-zeolite having a silicon to aluminium ratio greater than <NUM>, and/or in which the etherification is performed in the presence of a beta-zeolite and added tert-butyl alcohol. The processes provide glycerol di-tert-butyl ethers while reducing the generation of isobutylene dimers and trimers.

<CIT> discloses a process of making <NUM>-alkoxy-<NUM>-methyl-<NUM>-butanol using at least one specific zeolite catalyst selected from beta-zeolite and Y-zeolite when reacting IPEA (<NUM>-methyl-<NUM>-buten-<NUM>-ol) or PNA (<NUM>-methyl-<NUM>-buten-<NUM>-ol) with a primary alcohol having <NUM> to <NUM> carbon atoms.

<CIT> discloses a process for preparing polyol alkyl ethers by reacting compounds having at least three hydroxyl functionalities with olefins in the presence of acidic catalysts at a pressure of from <NUM> to <NUM> bar and a temperature of from <NUM> to <NUM> such that at least one of the hydroxyl functionalities is not reacted but the rest are replaced by an alkoxyl moiety.

The present disclosure provides methods of etherification, the methods including modifying a zeolite catalyst with phosphorus to provide a phosphorus modified zeolite catalyst having an atomic ratio of phosphorus to aluminum from <NUM>:<NUM> to <NUM>:<NUM> and a phosphorus loading from <NUM> to <NUM> weight percent based upon a total weight of the phosphorus modified zeolite catalyst; and contacting the phosphorus modified zeolite catalyst with an olefin and an alcohol to produce a monoalkyl ether, wherein the zeolite catalyst is a zeolite beta catalyst, and wherein the alcohol is a (poly)alkylene glycol.

In several places throughout the application, guidance is provided through lists of examples.

Methods of etherification are disclosed herein. The methods include modifying a zeolite catalyst with phosphorus to provide a phosphorus modified zeolite catalyst and contacting the phosphorus modified zeolite catalyst with an olefin and an alcohol to produce a monoalkyl ether, wherein the zeolite catalyst is a zeolite beta catalyst, and wherein the alcohol is a (poly)alkylene glycol.

Advantageously, the methods of etherification disclosed herein can provide an improved, i.e. greater, monoalkyl ether yield, as compared to etherifications that do not utilize the phosphorus modified zeolite catalyst, as discussed further herein. Improved monoalkyl ether yield, can be desirable for a number of applications, such as providing chemical intermediates. As an example, the monoalkyl ethers may be utilized as chemical intermediates in a surfactant production by ethoxylation process, making a greater monoalkyl ether yield desirable.

Additionally, the methods of etherification disclosed herein can provide an improved, i.e. greater, monoalkyl ether production rate, as compared to etherifications that do not utilize the phosphorus modified zeolite catalyst, as discussed further herein. Improved monoalkyl ether production rates can be desirable for a number of applications to provide desirable products with reduced production times and/or associated costs, for instance.

Zeolite catalysts are crystalline metallosilicates, e.g., aluminosilicates, constructed of repeating TO<NUM> tetrahedral units where T may be Si, Al or P (or combinations of tetrahedral units), for example. These units are linked together to form frameworks having regular intra-crystalline cavities and/or channels of molecular dimensions, e.g., micropores.

Embodiments of the present disclosure provide that the zeolite catalyst is a synthetic zeolite catalyst. Synthetic zeolite catalysts can be made by a known process of crystallization of a silica-alumina gel in the presence of alkalis and templates, for instance. Examples of synthetic zeolite catalysts include zeolite beta catalysts (BEA), Linde Type A (LTA), Linde Types X and Y (Al-rich and Si-rich FAU), Silicalite-<NUM>, ZSM-<NUM> (MFI), Linde Type B (zeolite P), Linde Type F (EDI), Linde Type L (LTL), Linde Type W (MER), and SSZ-<NUM> (MTT) as described using IUPAC codes in accordance with nomenclature by the Structure Commission of the International Zeolite Association. IUPAC codes describing Crystal structures as delineated by the Structure Commission of the International Zeolite Association refer to the most recent designation as of the priority date of this document unless otherwise indicated.

The present invention provides that the zeolite catalyst is a zeolite beta (BEA) catalyst. One or more embodiments provide that the zeolite catalyst includes a number of Bronsted acid sites, i.e., sites that donate protons.

The zeolite catalyst can have a SiO<NUM>/Al<NUM>O<NUM> mole ratio from <NUM>:<NUM> to <NUM>:<NUM> as measured using Neutron Activation Analysis. All individual values and subranges from <NUM>:<NUM> to <NUM>:<NUM> are included; for example, the zeolite catalyst can have a SiO<NUM>/Al<NUM>O<NUM> mole ratio from a lower limit of <NUM>:<NUM>, <NUM>:<NUM>, <NUM>:<NUM>, or <NUM>:<NUM> to an upper limit of <NUM>: <NUM>, <NUM>:<NUM>, <NUM>:<NUM>, or <NUM>:<NUM>.

The zeolite catalyst can have a mean pore diameter from <NUM> to <NUM> angstroms. All individual values and subranges from <NUM> to <NUM> angstroms are included; for example, the zeolite catalyst can have a mean pore diameter from a lower limit of <NUM> or <NUM> angstroms to an upper limit of <NUM> or <NUM> angstroms.

The zeolite catalyst can have surface area from <NUM> to <NUM><NUM>/g. All individual values and subranges from <NUM> to <NUM><NUM>/g are included; for example, the zeolite catalyst can have a surface area from a lower limit of <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM><NUM>/g to an upper limit of <NUM>, <NUM>, or <NUM><NUM>/g. Surface area is measured according to ASTM D4365 - <NUM>.

As mentioned, the zeolite catalyst can be made by a process that utilizes a template, which may also be referred to as an organic template. Templates may also be referred to as templating agents and/or structure-directing agents (SDAs). The template can be added to the reaction mixture for making the zeolite catalyst to guide, e.g., direct, the molecular shape and/or pattern of the zeolite catalyst's framework. When the zeolite catalyst making process is completed, the zeolite catalyst includes templates, e.g., templates located in the micropores of the zeolite catalyst. Templates are utilized in the formation of the zeolite catalyst. One or more embodiments provides that the template comprises ammonium ions. Zeolite catalyst that include templates can be made by known processes. Zeolite catalyst that include templates can be obtained commercially. Examples of suitable commercially available metallosilicate catalysts include CP814E, CP814C, CP811C-<NUM>, CBV <NUM>, CBV <NUM>, CBV <NUM>, CBV <NUM>, CBV 10A from ZEOLYST INTERNATIONAL™ of Conshohocken, PA.

Various templates that may be utilized for making zeolite catalysts are known. Examples of templates include tetraethylammonium hydroxide; N,N,N-trimethyl-<NUM>-adamante-ammonium hydroxide; hexamethyleneimine; and dibenzylmethylammonium; among others.

The present invention provides modifying a zeolite catalyst with phosphorus to provide a phosphorus modified zeolite catalyst. The phosphorus modification, e.g., phosphatation, may comprise impregnation. Impregnation may be referred to as incipient wetness impregnation or wet impregnation. Modifying the zeolite catalyst with phosphorus may utilize known conditions, e.g., known phosphorous impregnation conditions, and may utilize know equipment and known components. For instance, the zeolite catalyst may be contacted with an aqueous solution including a phosphorous compound. Examples of the phosphorous compound include, but are not limited to, phosphoric acid, monoammonium phosphate, diammonium phosphate, sodium phosphate, disodium phosphate, and combinations thereof.

Modifying a zeolite catalyst with phosphorus can include contacting the zeolite catalyst with a solution including a phosphorous compound. The solution may include water. Various amounts of phosphorous compound and/or water may be utilized for different applications.

The zeolite catalyst may be contacted with the aqueous solution including the phosphorous compound at temperature from <NUM> to <NUM>. All individual values and subranges from <NUM> to <NUM> are included; for example, the zeolite catalyst may be contacted with the aqueous solution including the phosphorous compound at temperature from a lower limit of <NUM>, <NUM>, or <NUM> to an upper limit of <NUM>, <NUM>, or <NUM>. The zeolite catalyst may be contacted with the aqueous solution including the phosphorous compound for various times for different applications.

The present invention provides that the phosphorus modified zeolite catalyst has an atomic ratio of phosphorus to aluminum from <NUM>:<NUM> to <NUM>:<NUM>. All individual values and subranges from <NUM>:<NUM> to <NUM>:<NUM> are included; for example, the phosphorus modified zeolite catalyst can have an atomic ratio of phosphorus to aluminum from a lower limit of <NUM>:<NUM>, <NUM>:<NUM> , <NUM>:<NUM> or to an upper limit of <NUM>:<NUM>, <NUM>:<NUM>, or <NUM>:<NUM>. The atomic ratio of phosphorus to aluminum is determined by a known process. The atomic ratio of phosphorus to aluminum is calculated based upon components utilized to make the phosphorus modified zeolite catalyst. For instance, known amounts of phosphorus and aluminum of the zeolite catalyst, e.g., based upon a structure of the zeolite catalyst, and a known amount of phosphorus utilized to make the phosphorus modified zeolite catalyst are utilized to calculate the atomic ratio of phosphorus to aluminum of the phosphorus modified zeolite catalyst.

The present invention provides that the phosphorus modified zeolite catalyst has a phosphorus loading, e.g., phosphorous provided via the phosphorus modification discussed herein, from <NUM> to <NUM> weight percent based upon a total weight of the phosphorus modified zeolite catalyst. All individual values and subranges from <NUM> to <NUM> weight percent are included; for example, the phosphorus modified zeolite catalyst can have a phosphorus loading from a lower limit of <NUM>, <NUM>, or <NUM> weight percent to an upper limit of <NUM>, <NUM>, or <NUM> weight percent based upon a total weight of the phosphorus modified zeolite catalyst. Phosphorus loading may be determined by a known process. For instance, phosphorus loading, e.g., nominal phosphorus loading, may be calculated based upon components utilized to make the phosphorus modified zeolite catalyst.

One or more embodiments of the present disclosure provide that following the modification with phosphorous, the phosphorus modified zeolite catalyst can be calcined. The phosphorus modified zeolite catalyst can be calcined at a temperature from <NUM> to <NUM>. All individual values and subranges from <NUM> to <NUM> are included; for example, the phosphorus modified zeolite catalyst may be calcined at from a lower limit of <NUM>, <NUM>, or <NUM> to an upper limit of <NUM>, <NUM>, or <NUM>.

The phosphorus modified zeolite catalyst can be calcined in a number of known calcination environments. For instance, the phosphorus modified zeolite catalyst can be calcined in an air environment.

The phosphorus modified zeolite catalyst can be calcined, i.e., exposed to a temperature from <NUM> to <NUM> in a calcination environment, from <NUM> hour to <NUM> hours. All individual values and subranges from <NUM> hour to <NUM> hours are included; for example, the phosphorus modified zeolite catalyst may be calcined at from a lower limit of <NUM> hour, <NUM> hours, or <NUM> hours to an upper limit of <NUM> hours, <NUM> hours, or <NUM> hours.

One or more embodiments provide that the methods disclosed herein include reducing e.g., removing, templates of the zeolite catalyst prior to the phosphorus modifying as discussed herein. Embodiments of the present disclosure provide that templates of the zeolite catalyst can be reduced by calcination.

To reduce templates, the zeolite catalyst may be calcined at temperature from <NUM> to <NUM>. All individual values and subranges from <NUM> to <NUM> are included; for example, the zeolite catalyst may be calcined at from a lower limit of <NUM>, <NUM>, or <NUM> to an upper limit of <NUM>, <NUM>, or <NUM> to reduce templates.

To reduce templates, the zeolite catalyst may be calcined in a number of known calcination environments. For instance, the zeolite catalyst may be calcined in an air environment.

To reduce templates, the zeolite catalyst may be calcined, i.e., exposed to a temperature from <NUM> to <NUM> in a calcination environment, from <NUM> hour to <NUM> hours. All individual values and subranges from <NUM> hour to <NUM> hours are included; for example, the zeolite catalyst may be calcined at from a lower limit of <NUM> hour, <NUM> hours, or <NUM> hours to an upper limit of <NUM> hours, <NUM> hours, or <NUM> hours.

The present invention is directed to methods of etherification. Etherification refers to a chemical process, e.g., chemical reaction, that produces ethers. The methods disclosed herein include contacting the phosphorus modified zeolite catalyst with an olefin and an alcohol to produce a monoalkyl ether.

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 includes from <NUM> to <NUM> carbon atoms. All individual values and subranges from <NUM> to <NUM> carbon atoms are included; for example, the olefin can include a lower limit of <NUM>, <NUM>, or <NUM> carbons to an upper limit of <NUM>, <NUM>, or <NUM> carbons.

The olefin may include alkenes such as alpha (α) olefins, internal disubstituted olefins, or cyclic structures (e.g., C<NUM>-C<NUM> cycloalkene). Alpha olefins include an unsaturated bond in the α-position of the olefin. Suitable α olefins may be selected from the group consisting of propylene, <NUM>-butene, <NUM>-hexene, <NUM>-methyl-<NUM>-pentene, <NUM>-heptene, <NUM>-octene, <NUM>-decene, <NUM>-dodecene, <NUM>-tetradecene, <NUM>-hexadecene, <NUM>-octadecene, <NUM>-icosene, <NUM>-docosene and combinations thereof. Internal disubstituted olefins include an unsaturated bond not in a terminal location on the olefin. Internal olefins may be selected from the group consisting of <NUM>-butene, <NUM>-pentene, <NUM>-hexene, <NUM>-hexene, <NUM>-heptene, <NUM>-heptene, <NUM>-octene, <NUM>-octene, <NUM>-octene, <NUM>-nonene, <NUM>-nonene, <NUM>-nonene, <NUM>-decene, <NUM>-decene, <NUM>-decene, <NUM>-decene and combinations thereof. Other exemplary olefins may include butadiene and styrene.

Examples of suitable commercially available olefins include NEODENE™ <NUM>-XHP, NEODENE™ <NUM>, NEODENE™ <NUM>, NEODENE™ <NUM>, NEODENE™ <NUM>, NEODENE™ <NUM>, NEODENE™ <NUM>, NEODENE™ <NUM>, NEODENE™ <NUM> from Shell, The Hague, Netherlands.

Embodiments of the present disclosure provide that the alcohol may comprise two hydroxyl groups, i.e., a glycol. The alcohol may include <NUM> carbons or greater, or <NUM> carbons or greater, or <NUM> carbons or greater, or <NUM> carbons or greater, or <NUM> carbons or greater, or <NUM> carbons or greater, or <NUM> carbons or greater, or <NUM> carbons or greater, while at the same time, <NUM> carbons or less, or <NUM> carbons or less, or <NUM> carbons or less, or <NUM> carbons or less, or <NUM> carbons or less, or <NUM> carbons or less, or <NUM> carbons or less, or <NUM> carbons or less. The alcohol may be selected from the group consisting of monoethylene glycol, diethylene glycol, propylene glycol, triethylene glycol, polyethylene glycol, monopropylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, <NUM>,<NUM>-propanediol, <NUM>,<NUM>-butanediol, <NUM>,<NUM>-butanediol, <NUM>,<NUM>-butanediol, <NUM>,<NUM>-hexanediol, <NUM>,<NUM>-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. The present invention provides 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, <NUM>,<NUM>-propane diol, <NUM>,<NUM>-butane diol, <NUM>,<NUM>-butane diol, <NUM>,<NUM>-butane diol, <NUM>,<NUM>-hexane diol, paraxylene glycol, glycerol, and <NUM>,<NUM>-cyclohexane methane diol. One or more embodiments provide that the (poly)alkylene glycol is monoethylene glycol.

Embodiments of the present disclosure provide that the alcohol and the olefin are reacted at a molar ratio of <NUM>:<NUM> to <NUM>:<NUM> moles of alcohol to moles of olefin. All individual values and subranges from <NUM>:<NUM> to <NUM>:<NUM> are included; for example, the alcohol and the olefin can be reacted at lower limit of <NUM>:<NUM>, <NUM>:<NUM>, or <NUM>:<NUM> to an upper limit of <NUM>:<NUM>, <NUM>:<NUM>, or <NUM>:<NUM> moles of alcohol to moles of olefin.

As mentioned, methods disclosed herein include contacting the phosphorus modified zeolite catalyst with an olefin and an alcohol to produce a monoalkyl ether. The olefin and the alcohol may contact the phosphorus modified zeolite catalyst under known etherification conditions and may utilize know reaction equipment and known reaction components. For instance, the olefin and the alcohol may contact the phosphorus modified zeolite catalyst in a slurry reactor, a fixed-bed reactor, or a fluidized-bed reactor. The reactor may operate in batch mode or continuous mode.

The phosphorus modified zeolite catalyst may be utilized in an amount such that the phosphorus modified zeolite catalyst is from <NUM>% to <NUM>% by weight based upon a total weight of the olefin, for instance. All individual values and subranges from <NUM>% to <NUM>% by weight are included; for example, the(phosphorus modified zeolite catalyst can be from a lower limit of <NUM>%, <NUM>%, or <NUM>% to an upper limit of <NUM>%, <NUM>%, or <NUM>% by weight based upon a total weight of the olefin.

The olefin and the alcohol may contact the phosphorus modified zeolite catalyst at a reaction temperature from <NUM> to <NUM>. All individual values and subranges from <NUM> to <NUM> are included; for example, the olefin and the alcohol may contact the phosphorus modified zeolite catalyst from a lower limit of <NUM>, <NUM>, or <NUM> to an upper limit of <NUM>, <NUM>, or <NUM>.

The reaction pressure may vary for different applications. For instance, the reaction pressure may be a reduced pressure, an atmospheric pressure, or an increased pressure.

Contacting the phosphorus modified zeolite catalyst with the olefin and the alcohol produces a monoalkyl ether. Various monoalkyl ethers may be produced for different applications, e.g., by varying which olefin is utilized and/or by varying which alcohol is utilized. Advantageously, the methods of etherification disclosed herein can provide an improved, i.e. greater, monoalkyl ether yield, as compared to etherifications that do not utilize the phosphorus modified zeolite catalyst as described herein.

Additionally, the methods of etherification disclosed herein can provide an improved, i.e. greater, monoalkyl ether production rate, as compared to etherifications that do not utilize the phosphorus modified zeolite catalyst as described herein.

In the Examples, various terms and designations for materials are used including, for instance, the following:.

Example <NUM> was performed as follows. Zeolite beta catalyst (CP 806EL) was calcined at <NUM> in an air environment for <NUM> hours to remove the templates from the zeolite beta catalyst. Then, the zeolite beta catalyst having the templates removed by calcination was modified with phosphorous as follows. The zeolite beta catalyst (<NUM> grams) and an aqueous phosphoric acid solution (<NUM> grams phosphoric acid; <NUM> grams deionized water) were added to a container with constant stirring for approximately <NUM> minutes at room temperature to provide a phosphorus modified zeolite catalyst. The phosphorus modified zeolite catalyst was dried in a box oven at <NUM> for <NUM> hour, and then calcined at <NUM> in an air environment for <NUM> hours. The phosphorus modified zeolite catalyst was calculated to have a nominal phosphorus content of <NUM> weight percent based upon a total weight of the phosphorus modified zeolite catalyst, and a phosphorus/aluminum atomic ratio of <NUM>:<NUM>.

Etherification was performed as follows. The phosphorus modified zeolite catalyst (<NUM> grams) was added to a vial reactor (<NUM>) with rare earth magnetic stir bars (Part #: VP 772FN-<NUM>-<NUM>-<NUM>, V&P Scientific, Inc. ); <NUM>-dodecene (<NUM> grams) and monoethylene glycol (<NUM> grams) were added to the vial reactor; the contents of the vial reactor were heated to <NUM> and stirred for <NUM> hours for the etherification. Then the contents of the vial reactor were analyzed by gas chromatography. The gas chromatography samples were prepared by adding contents of the vial reactor (<NUM>µL) to <NUM> of internal standard solution (<NUM> of hexadecane dissolved in <NUM> of ethyl acetate) and were then analyzed offline with an Agilent GC (<NUM>). For the analysis, dioxane, <NUM>-dodecene (<NUM>-C<NUM>) and isomers thereof (C<NUM>), <NUM>-dodecanol, diethylene glycol, monoalkyl ether and isomers thereof, and dialkyl ether and isomers thereof were included for product quantification such that the weight percent of species of interests were obtained.

Monoalkyl ether production rate (grams/hour/grams zeolite beta catalyst) was determined as follows: [net change of C<NUM> conversion x g of <NUM>-C<NUM> loaded x ME selectivity / <NUM> x <NUM> / g of catalyst / reaction time in h].

Dodecene derived species were monoether, diether, and <NUM>-dodecanol.

Total amount of dodecene derived species = monoether moles + 2x diether moles + <NUM>-dodecanol.

Total amount of dodecene, which includes <NUM>-dodecene and all non <NUM>-dodecene other C<NUM> isomers.

Dodecyl-monoether (ME) selectivity (%) was determined as: [total amount of ME]/[total amount of C<NUM> derived species] x <NUM>%.

Dodecyl-diether (DE) selectivity (%) was determined as: 2x[total amount of DE/[total amount of C<NUM> derived species] x <NUM>%.

Olefin conversion (%) was determined as: [total amount of C<NUM> derived species]/[total amount of C<NUM> derived species + total amount of dodecene] x <NUM>%.

Dodecyl-monoether (ME) yield (%) was determined as: C<NUM> conversion x dodecyl-monoether selectivity.

The results are reported in Table <NUM>.

Example <NUM> was performed the same as Example <NUM> with the change that the aqueous phosphoric acid solution included <NUM> grams phosphoric acid and <NUM> grams of deionized water.

Comparative Example A was performed the same as Example <NUM> with the change that <NUM> grams of the zeolite beta catalyst in which the templates were removed by calcination was utilized, and the aqueous phosphoric acid solution included <NUM> grams phosphoric acid and <NUM> grams of deionized water.

Comparative Example B was performed the same as Example <NUM> the change that the zeolite beta catalyst was not modified with phosphorus, i.e., no aqueous phosphoric acid solution was utilized.

The data of Table <NUM> illustrate that each of Examples <NUM>-<NUM> had an improved, i.e. greater, monoalkyl ether yield as compared to each of Comparative Examples A-B.

The data of Table <NUM> illustrate that each of Examples <NUM>-<NUM> had an improved, i.e. greater, monoalkyl ether production rate as compared to each of Comparative Examples A-B.

Example <NUM> was performed as follows. Zeolite beta catalyst (CP 814E) was calcined at <NUM> in an air environment for <NUM> hours to convert the catalyst from NH<NUM> form to H form; then the catalyst was modified with phosphorous as follows. Zeolite beta catalyst (<NUM> grams) and an aqueous phosphoric acid solution (<NUM> grams phosphoric acid; <NUM> grams deionized water) were added to a container and stirred for approximately <NUM> minutes at room temperature to provide a phosphorus modified zeolite catalyst. The phosphorus modified zeolite catalyst was dried in a box oven at <NUM> for <NUM> hour, and then calcined at <NUM> in an air environment for <NUM> hours. The phosphorus modified zeolite catalyst was calculated to have a nominal phosphorus content of <NUM> weight percent based upon a total weight of the phosphorus modified zeolite catalyst, and a phosphorus/aluminum atomic ratio of <NUM>:<NUM>. Etherification was performed as previously discussed with the change that the contents of the vial reactor were heated to <NUM> rather than <NUM> for the etherification and the etherification was for <NUM> hours; etherification results were determined as previously discussed.

Example <NUM> was performed as Example <NUM> with the change that the aqueous phosphoric acid solution included <NUM> grams phosphoric acid and <NUM> grams of deionized water.

Comparative Example C was performed as Example <NUM> with the change that <NUM> grams of zeolite beta catalyst (H form) was utilized, and the aqueous phosphoric acid solution included <NUM> grams phosphoric acid and <NUM> grams of deionized water.

Comparative Example D was performed as Example <NUM> with the change that the zeolite beta catalyst was not modified with phosphorus, i.e., no aqueous phosphoric acid solution was utilized.

The data of Table <NUM> illustrate that each of Examples <NUM>-<NUM> had an improved, i.e. greater, monoalkyl ether yield as compared to each of Comparative Examples C-D.

The data of Table <NUM> illustrate that each of Examples <NUM>-<NUM> had an improved, i.e. greater, monoalkyl ether production rate as compared to each of Comparative Examples C-D.

Example <NUM> was performed as Example <NUM> with the change that <NUM> grams of zeolite beta catalyst (H form) was utilized, the aqueous phosphoric acid solution included <NUM> grams phosphoric acid and <NUM> grams of deionized water; and for the etherification, the contents of the vial reactor were heated to <NUM> rather than <NUM> and the reaction was for <NUM> hour.

Comparative Example E was performed as Example <NUM> with the change that <NUM> grams of zeolite beta catalyst (H form) was utilized, the aqueous phosphoric acid solution included <NUM> grams phosphoric acid and <NUM> grams of deionized water; and for the etherification, the contents of the vial reactor were heated to <NUM> rather than <NUM> and the reaction was for <NUM> hour.

Comparative Example F was performed as Example <NUM> with the change that the zeolite beta catalyst was not modified with phosphorus, i.e., no aqueous phosphoric acid solution was utilized; and for the etherification, the contents of the vial reactor were heated to <NUM> rather than <NUM> and the reaction was for <NUM> hour.

The data of Table <NUM> illustrate that each of Examples <NUM>-<NUM> had an improved, i.e. greater, monoalkyl ether yield as compared to each of Comparative Examples E-F.

Claim 1:
A method of etherification, the method comprising:
modifying a zeolite catalyst with phosphorus to provide a phosphorus modified zeolite catalyst having an atomic ratio of phosphorus to aluminum from <NUM>:<NUM> to <NUM>:<NUM> and a phosphorus loading from <NUM> to <NUM> weight percent based upon a total weight of the phosphorus modified zeolite catalyst; and
contacting the phosphorus modified zeolite catalyst with an olefin and an alcohol to produce a monoalkyl ether;
wherein the zeolite catalyst is a zeolite beta catalyst, and wherein the alcohol is a (poly)alkylene glycol.