WO2018136218A1

WO2018136218A1 - Catalysts and methods for converting methyl ethyl ketone to butene

Info

Publication number: WO2018136218A1
Application number: PCT/US2017/068882
Authority: WO
Inventors: Zahraa ALAUDA; Keith HOHN
Original assignee: Higher Committee For Education Development; Kansas State University
Current assignee: Higher Committee For Education Development; Kansas State University
Priority date: 2017-01-19
Filing date: 2017-12-29
Publication date: 2018-07-26
Anticipated expiration: 2019-07-19

Abstract

Catalysts and methods are provided for producing high yields of butene. The inventive catalysts are bifunctional catalysts having both hydrogenation and dehydration functionalities. Preferred catalysts generally comprise elemental copper or a copper-containing compound supported on a sodium-modified aluminosilicate zeolite. The catalysts are useful in methods of reacting methyl ethyl ketone and hydrogen to produce high yields of butene. The present invention provides a simplified, renewable route to butene, with a number of practical applications.

Description

CATALYSTS AND METHODS FOR CONVERTING

METHYL ETHYL KETONE TO BUTENE

GOVERNMENT LICENSE RIGHTS

This invention was made with government support under Navy SBIR Contract #NG8335-13-C-0174 awarded by the Department of Defense. The government has certain rights in the invention

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention is generally directed to bifunctional metal catalysts and methods for producing high yields of butene.

Description of the Prior Art

Conventional methods of producing butene rely on petrochemicals, as butene is a side-product of petroleum refining. Renewable routes to butene have been explored. One method includes the catalytic reaction of acetic acid and propionic acid in the presence of hydrogen in order to produce a mixture of olefins, including butene. This method includes fermentation to produce the feedstocks but requires the use of two separate fermentations to produce acetic acid and propionic acid. Another method involves a multi-step process for producing butanol from 2,3-butanediol and requires an additional catalytic step to further dehydrate the butanol to butene. The present invention is directed to simplified methods of producing high yields of butene and to catalytic compositions for use in such methods.

SUMMARY OF THE INVENTION

In one embodiment, there is provided a method of producing butenes. The method comprises reacting a reaction mixture comprising methyl ethyl ketone and hydrogen with a bifunctional copper-containing catalyst having hydrogenation and dehydration functionalities. In another embodiment, there is provided a bifunctional catalyst composition having hydrogenation and dehydration functionalities. The catalyst comprises elemental copper or a copper-containing compound supported on sodium aluminosilicate zeolite and is capable of converting methyl ethyl ketone and hydrogen to butene.

DETAILED DESCRIPTION OF THE PREFERRED EMB ODEVIENT

Embodiments of the present invention are directed to catalysts and methods for converting methyl ethyl ketone (MEK) to butene with a high yield.

Catalysts for use in embodiments of the present invention generally comprise bifunctional catalyst compositions. As used herein, the term "bifunctional" refers to catalysts having both hydrogenation and dehydration functionalities. In certain preferred embodiments, the bifunctional catalyst composition is a copper-containing bifunctional catalyst composition. However, in certain other embodiments, other non-copper bifunctional metals may be used. The catalyst compositions comprise a metal compound (e.g., elemental copper or a copper-containing compound) supported on a catalyst support material. In certain embodiments, the metal compound is loaded on the support material at about 5% to about 30% by weight, preferably about 10% to about 25% by weight, and more preferably about 15% to about 20% by weight, based on the total weight of the composition taken as 100% by weight. In certain embodiments, the catalyst support material is γ-alumina or aluminosilicate zeolite. In preferred embodiments, the support material is a sodium modified zeolite, such as sodium-modified Y zeolite or sodium- modified mordenite zeolite. Without being bound by any theory, it is believed that inclusion of sodium in the support material creates basic sites that reduce (or eliminate) butane formation and improve selectivity to butene. In such embodiments, the catalyst support material is preferably a sodium modified zeolite having a silica-to-alumina ratio of greater than about 3, although zeolites having other silica-to-alumina ratios are within the scope of the present invention. In certain embodiments, the catalyst support material or catalyst composition is a porous material having an average pore diameter of about 1 nm to about 100 nm, preferably about 2 nm to about 50 nm (i.e., mesoporous). Copper-containing catalysts of the present invention can be used to produce high yields of butene from MEK. Accordingly, a method of producing butenes is provided. The method comprises reacting a reaction mixture comprising MEK and hydrogen with the bifunctional copper-containing catalyst. In certain embodiments, the reaction is carried out at a temperature of about 150 °C to about 300 °C, preferably about 175 °C to about 250 °C, and more preferably about 190 °C to about 225 °C. In particularly preferred embodiments, the reaction is carried out at a temperature of about 200 °C.

The primary product of the reaction described above is butene. For example, in certain embodiments, the reaction achieves at least about 85%, preferably at least about 95% molar selectivity to butene. These high selectivities can be achieved even when high conversion of MEK are achieved. For example, conversions in excess of at least about 85%) can be achieved while selectivity to butene is greater than about 95%>. Butene has several isomeric forms, and the embodiments of the present invention generally produce a mixture of butenes composed of 1 -butene and 2-butene (cis and trans). In certain preferred embodiments, a higher yield of 1 -butene is selectively produced. For example, in certain embodiments, the present invention achieves at least about 10%>, preferably at least about 15%), and more preferably at least about 17%> selectivity to 1 -butene production. In certain preferred embodiments, the reaction achieves high selectivity to butene while producing little or no butane. In such embodiments, the reaction produces less than about 20 mol%>, preferably less than about 15 mol%> butane, more preferably less than about 10 mol%> butane, and even more preferably less than about 5 mol%> butane. In other such embodiments, the reaction produces about 0 mol%> butane.

Methods in accordance with the present invention may further comprise additional process steps or reactions. For example, the methods may comprise additional steps to produce the MEK to be used in the reaction described above. Fermentation of biomass- derived sugars to 2,3-butanediol is known in the art, and it has also been shown that 2,3- butanediol can be dehydrated to MEK with high yield. Therefore, methods in accordance with embodiments of the present invention may further comprise fermentation of biomass- derived sugars to 2,3-butanediol and dehydration of 2,3-butanediol to MEK. In certain embodiments, the biomass-derived sugars are supplied by a feedstock selected from the group consisting of corn, grains, sugar cane, beet sugar, grasses, woody biomass, and mixtures thereof. These steps provide a high yield of MEK, which can be used as the reactant for the catalytic conversion to butene described above. This combination provides an efficient path for converting biomass-derived sugars to butene.

Embodiments of the present invention have a number of applications, due to the variety of industrial uses for butene. For example, 1 -butene can be dimerized and oligomerized to produce fuel. It can also be reacted with branched alkanes such as isobutene to produce a mixture of highly branched paraffins, which have excellent antiknock properties. In other applications, 1 -butene can be incorporated into low-density polyethylene, making the resultant material more flexible. In chemical plants, butene can be dehydrogenated to produce butadiene, an important commodity chemical for making synthetic rubber and other polymers. Additionally, butene can be converted to other four- carbon-containing chemicals, such as maleic anhydride. This is a non-exhaustive list of advantages and applications for the present invention, and various other advantages and applications will be apparent from the preceding description and the following examples.

EXAMPLES

The following examples set forth experiments for evaluating butene selectivity using various catalysts. It is to be understood, however, that these examples are provided by way of illustration and nothing therein should be taken as a limitation upon the overall scope of the invention.

EXAMPLE I

In this experiment, alternate routes for butene production were evaluated. Conversion of 2,3-BDO to butene can be achieved with good yields. However, this experiment was aimed at evaluating whether separating the 2,3-BDO dehydration and methyl ethyl ketone (MEK) conversion to butene steps into two separate processes would lead to higher process efficiency (higher butene yield). As is well known in the literature, MEK can be produced at high yields by dehydration of 2,3-BDO. Thus, catalysts were tested and compared for their ability to convert MEK to butene, preferentially 1 -butene, via hydrogenation of MEK to butanol and then dehydration of butanol to butene.

In this experiment, the butene selectivity of three different catalysts was tested and compared. Cu/NaY Zeolite, Cu/Na Mordenite Zeoltie, and Cu/y-AhCb catalysts were each used to catalyze butene formation from a reaction of methyl ethyl ketone with hydrogen. These results were obtained for a reaction temperature of 270°C, catalyst mass of 1 gram, total H₂ and N₂ flow rate of 85 mL/min, MEK flow rate of 1 mL/h, and an H₂/MEK ratio of 5. Table 1 shows the MEK conversion and selectivities to major products for the three catalysts. As shown in Table 1, both Na Y and Na Mordenite catalyst provide butene selectivities in excess of 95% at MEK conversion greater than 84%.

Table 1. Comparison of three copper catalysts for conversion of methyl ethyl ketone to butene.

al gm of the catalyst with 2gm of quartz sand, ZYNa is zeolite Y sodium and ZMNa is zeolite mordenite sodium.

bl gm of the catalyst alone.

EXAMPLE II

In this experiment, the performances of 20% Cu/NaY was evaluated for a range of reaction temperatures. Table 2 shows the results for four reaction temperatures. For all four temperatures, data were taken after two hours of operation. As shown in Table 2, both MEK conversion and butene selectivity increase with temperature up until a point. Beyond 270°C, both drop. Without being bound by any theory, it is believed this is due to faster rates of deactivation of the catalyst at 290°C that causes lower MEK conversion and butene selectivity after two hours than lower temperature.

Table 2. MEK Mix- 1- Trans- Cis- Butane

Temp.

Conv. Butene Butene Butene Butene Sel.

°C

(mole %) Sel. (%) Sel. (%) Sel. (%) Sel. (%) (%)

290 86.68 86.2 17.64 38.08 30.48 0

270 97.05 97.26 19 43.66 34.6 0

250 91.2 95.27 17.52 42.01 35.74 0

230 64.52 55.59 9.68 22.75 23.16 0

EXAMPLE III

In this experiment, the effect of copper loading was studied. Cu/NaY catalysts with copper weight loadings between 8 and 20% were synthesized and compared. Reaction conditions were the same as described in Example I, and all data were taken after the catalysts were used for two hours. Table 3 shows the results for the four catalysts. As shown in this table, increasing copper loading generally increases both MEK conversion and butene selectivity, although increasing the copper weight loading from 20 to 26% leads to a decrease in both conversion and selectivity.

Table 3.

Claims

Claims :

1. A method of producing butenes comprising reacting a reaction mixture comprising methyl ethyl ketone and hydrogen with a bifunctional catalyst having hydrogenation and dehydration functionalities.

2. The method of claim 1, wherein the bifunctional catalyst comprises elemental copper or a copper-containing compound loaded on a support material.

3. The method of claim 2, wherein the bifunctional catalyst comprises about 5 to about 30 weight % of said elemental copper or said copper-containing compound.

4. The method of claim 1, wherein the bifunctional catalyst is supported on γ-alumina or aluminosilicate zeolite.

5. The method of claim 4, wherein the bifunctional catalyst is supported on sodium-modified aluminosilicate zeolite.

6. The method of claim 1, wherein the reacting occurs at a temperature of about 150 °C to about 300 °C.

7. The method of claim 1, further comprising:

fermenting biomass-derived sugars to 2,3-butanediol; and

dehydrating the 2,3-butanediol to the methyl ethyl ketone of the reaction mixture.

8. The method of claim 7, wherein said biomass-derived sugars are supplied by a feedstock selected from the group consisting of corn, grains, sugar cane, beet sugar, grasses, woody biomass, and mixtures thereof.

9. The method of any of claims 1-8, wherein the reacting achieves at least about 85% molar conversion of the methyl ethyl ketone.

10. The method of any of claims 1-9, wherein the reacting has a butene selectivity of at least about 95 mol%.

11. The method of any of claims 1-10, wherein the reacting produces less than about 20 mol% of butane.

12. The method of claim 11, wherein the reacting produces about 0 mol% of butane.