JP2015510885A - Preparation of alpha, beta-unsaturated carboxylic acids and esters thereof - Google Patents

Abstract

The L-type zeolite, the modified L-type zeolite, or any combination thereof includes a dehydroxylation reaction and optionally an α, β-unsaturated carboxylic acid and / or ester thereof through a reaction pathway that may include an esterification reaction. Useful for preparation via catalysis. In certain reaction pathways, the dehydroxylation reaction and the esterification reaction may be performed sequentially or simultaneously.

Description

(Cross-reference of related applications)
This application is filed on US Provisional Patent Application No. 61 / 608,053 filed on March 7, 2012; US Provisional Patent Application Number 61 / 740,230 filed on December 20, 2012; and February 26, 2013. Claims the benefit of US Patent Application No. 13 / 819,035.

(Field of Invention)
The present invention relates to a process for producing an α, β-unsaturated carboxylic acid and / or ester thereof using a catalyst.

  Acrylic acid and its ester derivatives are important commercial chemicals used in the production of polyacrylic acid esters, elastomers, superabsorbent polymers, floor polishes, adhesives, paints and the like. Acrylic acid has historically been produced by hydroxycarboxylation of acetylene. This method utilizes nickel carbonyl and high pressure carbon monoxide, both of which are expensive and are considered environmentally unfriendly. Other methods, such as those utilizing ethenone and ethylene cyanohydrin, generally have similar unexpected disadvantages.

  In particular, in an attempt to reduce the impact on the environment, lactic acid can be derived from biological resources such as renewable sugarcane, so dehydroxylation of lactic acid has been studied as a route to produce acrylic acid. . Solid catalysts have been investigated primarily for use in both the liquid and gas phase dehydroxylation reactions that convert lactic acid to acrylic acid. Specific solid catalysts that have been investigated include sodium phosphate and aluminosilicates supported on silica or weak acids supported on silica. It becomes clear that the dehydroxylation reaction performed with some of these catalysts proceeds only at a high temperature exceeding 350 ° C. If it is scaled up, it is necessary to add a considerable energy cost. Furthermore, many solid catalysts, including those described above, have poor selectivity for acrylic acid (ie, there are multiple by-products that need to be removed, which leads to increased manufacturing costs. ), The overall yield of the reaction was found to be low. Therefore, the cost of producing acrylic acid by dehydroxylating lactic acid is still very high.

  The present invention relates to a process for preparing α, β-unsaturated carboxylic acids and / or esters thereof using a catalyst.

  One embodiment of the present invention includes α-hydroxycarboxylic acid, α-hydroxycarboxylic acid ester, β-hydroxycarboxylic acid, β-hydroxycarboxylic acid ester, α-alkoxycarboxylic acid, α-alkoxycarboxylic acid ester, β- Providing a composition comprising a reactant selected from the group consisting of an alkoxy carboxylic acid, a β-alkoxy carboxylic ester, a lactide, and any combination thereof; and contacting the composition with a dehydroxylation catalyst A dehydroxylation reaction to produce a product comprising an α, β-unsaturated carboxylic acid and / or an ester thereof, wherein the dehydroxylation catalyst is an L-type zeolite, a modified L-type zeolite, and Including at least one selected from the group consisting of any combination thereof. A method characterized in that.

  Another embodiment of the present invention includes α-hydroxycarboxylic acid, α-hydroxycarboxylic acid ester, β-hydroxycarboxylic acid, β-hydroxycarboxylic acid ester, α-alkoxycarboxylic acid, α-alkoxycarboxylic acid ester, β- Providing a composition comprising a reactant selected from the group consisting of an alkoxycarboxylic acid, a β-alkoxycarboxylic acid ester, a lactide, and any combination thereof; and contacting the composition with an alcohol and a catalyst; Performing an esterification reaction and a dehydroxylation reaction simultaneously, thereby producing a product comprising an α, β-unsaturated carboxylic acid ester, wherein the catalyst is an L-type zeolite, a modified L-type zeolite, and any of them Including at least one selected from the group consisting of To provide a method for the butterflies.

  Yet another embodiment of the present invention is a reactant selected from the group consisting of α-hydroxy carboxylic acid, β-hydroxy carboxylic acid, α-alkoxy carboxylic acid, β-alkoxy carboxylic acid, and any combination thereof. An esterification reaction is performed by contacting the composition with an esterification catalyst and an alcohol, thereby producing an intermediate containing an ester of the reactant; Performing a dehydroxylation reaction by contacting with a hydroxylation catalyst, thereby producing a product comprising an α, β-unsaturated carboxylic acid ester, wherein the dehydroxylation catalyst is an L-type zeolite, a modified L-type A method comprising at least one selected from the group consisting of zeolite and any combination thereof Subjected to.

  Another aspect of the invention includes a reactant selected from the group consisting of α-hydroxy carboxylic acid, β-hydroxy carboxylic acid, α-alkoxy carboxylic acid, β-alkoxy carboxylic acid, and any combination thereof. Providing the composition; contacting the composition with an alcohol to effect an esterification reaction, thereby producing an intermediate comprising an ester of the reactant, wherein the esterification reaction is carried out using an external catalyst. Then performing a dehydroxylation reaction by contacting the intermediate with a dehydroxylation catalyst, thereby producing a product comprising an α, β-unsaturated carboxylic acid ester, the dehydroxylation The catalyst comprises at least one selected from the group consisting of L-type zeolite, modified L-type zeolite, and any combination thereof. A method characterized by.

  Another embodiment of the present invention includes α-hydroxycarboxylic acid, α-hydroxycarboxylic acid ester, β-hydroxycarboxylic acid, β-hydroxycarboxylic acid ester, α-alkoxycarboxylic acid, α-alkoxycarboxylic acid ester, β- Providing a composition comprising a reactant selected from the group consisting of an alkoxy carboxylic acid, a β-alkoxy carboxylic ester, a lactide, any combination thereof; and dehydroxylating the composition in the presence of a carrier gas Performing a dehydroxylation reaction by contacting with a catalyst, thereby producing a product comprising an α, β-unsaturated carboxylic acid and / or an ester thereof, wherein the carrier gas comprises from about 90% carbon dioxide Providing a method characterized in that it contains more.

  Another embodiment of the present invention comprises producing acrylic acid or an acrylate ester from a reactant derived through a fermentation process that includes a biological catalyst and a biological source, the biological supply The source comprises at least one of glucose, sucrose, glycerol and any combination thereof and the reactants are α-hydroxycarboxylic acid, α-hydroxycarboxylic acid ester, β-hydroxycarboxylic acid, β-hydroxycarboxylic acid Comprising one selected from the group consisting of an ester, an α-alkoxycarboxylic acid, an α-alkoxycarboxylic acid ester, a β-alkoxycarboxylic acid, a β-alkoxycarboxylic acid ester, a lactide, and any combination thereof. To provide a method.

  Yet another embodiment of the present invention comprises producing acrylic acid or an acrylate ester from a reactant derived through a chemical process that includes a chemical catalyst and a biological source, the biological source Comprises at least one of glucose, sucrose, glycerol and any combination thereof and the reactant is α-hydroxycarboxylic acid, α-hydroxycarboxylic acid ester, β-hydroxycarboxylic acid, β-hydroxycarboxylic acid ester , Α-alkoxycarboxylic acid, α-alkoxycarboxylic acid ester, β-alkoxycarboxylic acid, β-alkoxycarboxylic acid ester, lactide, and any combination thereof. Provide a way to do it.

  The features and advantages of the present invention will be apparent to those skilled in the art from the following description of the preferred embodiment.

  The following drawings are used to illustrate particular embodiments of the invention and are not meant to be exclusive embodiments. The content of the disclosure may be subject to considerable modifications, changes, combinations and equivalents in form and function as would occur to one of ordinary skill in the art and to those who would benefit from this disclosure.

Non-limiting examples of several different reaction pathways described herein are given.

FIG. 4 shows an exemplary systematic diagram used to prepare α, β-unsaturated carboxylic acids and / or esters thereof according to at least some embodiments of the present invention.

1 shows a chemical pathway for converting triglycerides to acrylic acid using a chemical catalyst.

1 shows a chemical pathway for converting glucose to acrylic acid using a chemical catalyst.

FIG. 4 shows the conversion and selectivity of a reaction performed using L-type zeolite according to at least some embodiments of the present invention.

FIG. 4 shows the conversion and selectivity of reactions performed using L-type zeolite and regenerated L-type zeolite according to at least some embodiments of the present invention.

FIG. 4 shows the conversion and selectivity of a reaction performed using L-type zeolite according to at least some embodiments of the present invention.

  The present invention relates to a process for preparing α, β-unsaturated carboxylic acids and / or esters thereof using a catalyst.

  The present invention, in at least some embodiments, utilizes an L-type zeolite catalyst to effectively (ie, high conversion) and selectively α, β-unsaturated carboxylic acids (eg, acrylic acid) and / or Alternatively, a reaction route for producing the ester from a reactant such as lactic acid is provided. As further described herein, surprisingly, the L-type catalyst is more effective and selective in certain embodiments, such as an α, β-unsaturated carboxylic acid (eg, acrylic acid) and / or It has been clarified that the ester is produced from a reactant such as lactic acid. As a result, the reaction pathways and catalysts described herein can provide, in certain embodiments, cost-effective and environmentally friendly production of environmentally friendly acrylic acid from lactic acid.

  Where “about” is used herein at the beginning of a listed number, “about” modifies each number of the listed number. When enumerating numbers to indicate a range, in some cases it may be greater than the enumerated upper limit if there is an enumerated lower limit. One skilled in the art will appreciate that in the selected subset, the upper limit needs to be selected beyond the selected lower limit.

  As used herein, the term “reaction pathway” refers to a reaction or series of reactions that converts a reactant to a product comprising an α, β-unsaturated carboxylic acid or ester thereof, which reaction or series of reactions. If desired, intermediates may be formed in the reaction. In certain embodiments, the reaction pathway of the present invention may comprise a dehydroxylation reaction utilizing a dehydroxylation catalyst comprising L-type zeolite. In certain embodiments, the reaction pathway of the present invention may further comprise an esterification reaction.

  As used herein, the term “dehydroxylation reaction” refers to the removal of water from a reactant. The term “dehydroxylation reaction” is also known in the art as a dehydration reaction.

  FIG. 1 shows non-limiting examples of several different reaction pathways of the present invention. For example, in one embodiment (starting with a starting composition containing the reactants) as shown in Reaction Pathway 1 of FIG. 1, the reaction route of the present invention is an esterification that produces an intermediate that includes an ester of the reactant. Reaction (1A) may be followed by a dehydroxylation reaction (1B) that produces a product comprising an ester of an α, β-unsaturated carboxylic acid. In another embodiment shown in Reaction Pathway 2 of FIG. 1 (starting with a starting composition containing the reactants), the reaction path of the present invention is a reaction that produces an intermediate comprising an α, β-unsaturated carboxylic acid. The hydroxylation reaction (2A) may be followed by an esterification reaction (2B) that produces a product containing an ester of an α, β-unsaturated carboxylic acid. In yet another embodiment (starting with a starting composition containing reactants) as shown in Reaction Pathway 3 of FIG. 1, the reaction path of the present invention comprises a product comprising an α, β-unsaturated carboxylic acid. The resulting dehydroxylation reaction (3) may be included. In another embodiment shown in Reaction Path 4 of FIG. 1 (starting with a starting composition containing reactants), the reaction path of the present invention produces a product comprising an ester of an α, β-unsaturated carboxylic acid. Simultaneous dehydroxylation and esterification (4) may be included.

Suitable reactants for use in connection with the reaction pathway of the present invention include, but are not limited to, α-hydroxy carboxylic acid, α-hydroxy carboxylic acid ester, β-hydroxy carboxylic acid, β-hydroxy carboxylic acid ester, α -Alkoxy carboxylic acid, (alpha) -alkoxy carboxylic acid ester, (beta) -alkoxy carboxylic acid, (beta) -alkoxy carboxylic acid ester, etc., and those combinations are mentioned. Suitable esters described above _may be a C 1 _{-C 10} alkyl esters. Specific examples of reactants include, but are not limited to, lactic acid, lactic acid salts (eg, calcium, ammonium, magnesium, sodium and potassium salts thereof), lactic acid alkyl esters, lactide, methyl lactate, butyl lactate, 3 -Hydroxypropionic acid, 3-hydroxypropionic acid alkyl ester, methyl 3-hydroxypropionate, butyl 3-hydroxypropionate, lactamide, and any combination thereof. In certain embodiments, the reactant may be in the form of a solid, liquid, solution or gas. Furthermore, the reactant is a substantially pure chiral reactant or a racemic mixture of chiral reactants, such as D (-) lactic acid, L (+) lactic acid, DD lactide, LL lactide, D / L racemic mixture of lactic acid, Alternatively, it may be a D / L racemic mixture of lactide.

  Reactants suitable for use in connection with the reaction pathways of the present invention may be prepared by any known means. In certain embodiments, the reactants may be biologically derived, chemically derived, or a combination thereof. Examples of biologically derived reactants are described in international patent application PCT / US11 / 50707 (invention title “Catalytic Dehydroxylation of Lactic Acid and Lactic Acid Esters”), the contents of which are incorporated herein by reference in their entirety. Indicated). By way of example and not limitation, lactic acid is produced from microorganisms (eg, acid-resistant homolactic bacteria) (microorganisms utilizing and / or metabolizing sucrose, glucose, etc. derived from sugar cane, beet, whey, etc.). It may be derived from lactate (eg, ammonium lactate) present in the fermentation broth.

  In certain embodiments, the α-hydroxy carboxylic acids described herein (eg, lactic acid and its derivatives) may be obtained from a fermentation broth. In certain embodiments, the fermentation broth described herein is a bacterial species, including Escherichia coli and Bacillus coagulans, selected to produce lactic acid on a commercial scale. It may be derived from the culture medium. In certain embodiments, the fermentation broth described herein may be derived from a culture of a filamentous fungal species selected for lactic acid production. In certain embodiments, the fermentation broth described herein may be derived from a yeast species known to produce lactic acid on an industrial scale. Microorganisms suitable for the production of lactic acid on a commercial scale include, in certain embodiments, Escherichia coli, Bacillus coagulans, Lactobacillus delbrucci, El Bulgaricus, El Thermophilus, El Lakemanni, El Cathay, El Fermenti, Streptococcus thermophilus, S. lactis, S. faecalis, Pediococcus sp., Leuconostoc sp., Bifidobacterium sp., Rhizopus oryzae and a variety of industrially used yeast species. Those skilled in the art from the disclosure herein should understand any suitable combination of the bacteria described above.

  The fermentation process that produces lactic acid, such as α-hydroxy carboxylic acid, in certain embodiments may be a batch process, a continuous process, or a hybrid thereof. A wide variety of carbohydrate materials derived from natural resources can be used as feedstock in conjunction with the fermentative production of α-hydroxy carboxylic acids described herein. For example, sucrose from sugar cane and beet, glucose, lactose-containing whey, maltose and dextrose from hydrolyzed starch, glycerol from the biodiesel industry, and combinations thereof are described herein as α-hydroxy carboxylic acids Suitable for fermentation production. Alternatively, pentose derived from hydrolysis of cellulosic biomass may be used to produce the microorganism described above, which has the ability to produce α-hydroxycarboxylic acid. In certain embodiments, a microorganism that can simultaneously utilize both a 6-carbon containing sugar, such as glucose, and a 5-carbon containing sugar, such as xylose, to produce lactic acid is a preferred biocatalyst in the fermentation production of lactic acid. It is. In certain embodiments, the hydrolyzate derived from an inexpensive cellulosic material has sugars that contain both C-5 and C-6 carbons, and C-5 and C-6 in the production of lactic acid. Biocatalysts having the ability to simultaneously utilize carbon-containing sugars are highly preferred because they are suitable for converting lactic acid to acrylic acid and acrylate esters at low cost.

  In certain embodiments, fermentation broths for the production of lactic acid include those of acid resistant homolactic bacteria. The term “homolactic acid” means that the strain produces substantially only lactic acid as a fermentation product. Acid-tolerant homolactic bacteria are typically isolated from grain soaking in commercial grain grinders. In certain embodiments, acid resistant microorganisms that can grow at high temperatures are preferred. In certain preferred embodiments, microorganisms capable of producing at least 4 g of lactic acid per liter of fermentation fluid (more preferably 50 g of lactic acid per liter of fermentation fluid) are utilized in the fermentation operations described herein. May be.

  In certain embodiments, the fermentation broth is subjected to various unit operations such as filtration, acidification, polishing, concentration, etc. at various points in production, or multiple times of the unit operations described above. May be used later. In certain embodiments, if the fermentation broth contains about 6 to about 20% lactic acid based on weight / weight (w / w), the lactic acid may be recovered in a concentrated form. Recovery from the fermentation broth in concentrated form of lactic acid can be accomplished by multiple methods known in the art and / or combinations of methods known in the art.

During the fermentation process described herein, at least one alkaline material (eg, NaOH, CaCO ₃ , (NH ₄ ) ₂ CO ₃ , NH ₄ HCO is used to maintain the pH of the growth medium near neutral. ₃ , NH ₄ OH, KOH, or any combination thereof). The addition of alkaline material to the fermentation broth sometimes results in accumulation in the form of an inorganic salt of lactic acid. In certain embodiments, ammonium hydroxide is a preferred alkaline material for maintaining a neutral pH of the fermentation broth. Even if ammonium hydroxide is added to the fermentation medium, ammonium lactate may accumulate in the fermentation broth. Since aqueous solutions of ammonium lactate are highly soluble, they may be present at high concentrations in the fermentation broth. As one method for obtaining lactic acid from fermentation broth containing ammonium lactate, the fermentation broth is subjected to microfiltration and ultrafiltration, followed by continuous ion exchange (CIX), simulated moving bed chromatography (SMB), electrodialysis. Subsequent to bipolar membrane (EDBM), fixed bed ion exchange, or liquid-liquid extraction. In certain embodiments, the sample effluxed by fixed bed ion exchange may then be subjected to bipolar electrodialysis to obtain lactic acid in the form of concentrated free acid.

  In certain embodiments, the reactants (eg, lactic acid and lactate esters) are biologically fed through one or more chemical processes (process using a chemical catalyst) regardless of any fermentation process (process using a biocatalyst). It may be derived from a source (eg glucose, sucrose and glycerol). For example, lactic acid and lactic acid esters derived from biological sources may be substantially subjected to dehydroxylation and esterification reactions as described above to obtain acrylic acid and acrylate esters.

  In other examples, glycerol may be used as a starting material to produce lactic acid, and then a chemical process may be used to produce acrylic acid independent of any fermentation process (eg, FIG. 3). The production of biodiesel by transesterification of fatty acid esters derived from vegetable oil has increased several times globally over the past decade, and in part has replaced the use of fossil-derived diesel fuel. Glycerol, a byproduct of the biodiesel industry, is a preferred or, in some embodiments, a preferred starting material for producing acrylic acid and acrylate esters according to the process described in the present invention.

  For example, one method of producing lactic acid from glycerol is a thermochemical conversion that converts glycerol to lactic acid through intermediate compounds such as glyceraldehyde, 2-hydroxypropenal and pyruvaldehyde at temperatures above about 550 ° C. A method may be used. However, thermochemical conversion methods cause significant degradation of pyruvaldehyde and lactic acid at this high temperature, thereby reducing the selectivity of lactic acid production. In some cases, the use of a chemical catalyst that mediates the dehydrogenation reaction involved in the production of lactic acid allows for a decrease in temperature, thereby improving selectivity and reducing degradation. In some cases, heterogeneous catalysts are preferred because they can be recovered and reused many times, do not need to be buffered, and operate in a continuous flow process mode instead of a batch process mode. Because it can be easily modified to increase throughput and turnover time. These benefits may result in a significant reduction in operating costs and waste disposal.

  Suitable heterogeneous catalysts for the conversion of glycerol to lactic acid may include metals, including but not limited to nickel, cobalt, copper, platinum, palladium, ruthenium, rhodium, any combination thereof. In certain embodiments, the heterogeneous catalyst may optionally be supported on a support including, but not limited to, carbon, silica, alumina, titania, zirconia, zeolite, and the like. In certain embodiments, the reaction mixture may further comprise additional hydrogen or oxygen. In certain embodiments, the catalyst selected may be used without additional hydrogen or oxygen.

  In certain embodiments, the heterogeneous catalyst comprising a metal is used in the presence of an alkaline component including, but not limited to, alkali metals, alkaline earth metal hydroxides, solid bases, and any combination thereof. May be. In certain preferred embodiments, the conversion of glycerol to lactic acid uses a copper-based catalyst with a base promoter, but may be utilized in a single pot reaction without the use of a reducing or oxidizing agent.

  In certain embodiments, acrylic acid may be made from sucrose. In some cases, sucrose may be hydrolyzed to produce glucose and fructose. In some cases, it is observed that fructose is then converted directly to lactic acid in a near stoichiometric yield using a chemical catalyst, while the conversion of glucose to lactic acid is obtained in about 64% yield. It was. Some embodiments themselves hydrolyze sucrose to produce glucose and fructose; isomerize the glucose to obtain fructose; and convert the combined fructose to lactic acid using a chemical catalyst You may include that. Similarly, in certain embodiments, the method may include hydrolyzing starch to produce glucose; isomerizing the glucose to obtain fructose; and converting fructose to lactic acid using a chemical catalyst.

  The chemical-catalyzed conversion of fructose (fructose together or from individual sources) to lactic acid involves the retro-aldol reaction of fructose, as shown in FIG. 4, and includes dihydroxyacetone (DHA) and glycerol. Ceraldehyde (GLY) may be produced and then they may be converted together to pyruvaldehyde (PAL) by dehydration and rearrangement. PAL may be further converted to the desired alkyl lactate or lactic acid under the action of a Lewis acid in an alcoholic solvent or water. Then, in some cases, lactic acid and alkyl lactate may be converted to acrylic acid and acrylate esters using a zeolite catalyst at about 330 ° C.

  Lewis acidic zeolites, such as Sn-Beta, showed surprisingly high activity and selectivity for the conversion of sucrose, glucose and fructose to lactic acid esters. In some embodiments, the solid Lewis acidic catalyst may include a zeotype material, which in certain preferred embodiments is further incorporated into a framework of a zeotype material, such as a tetravalent metal, such as Sn, Pb, Ge, Ti. , Zr, and / or Hf. For example, the solid Lewis acidic catalyst may comprise a zeotype material and tetravalent Sn and / or tetravalent Ti.

  Examples of suitable zeotype materials include, but are not limited to, structural BEAs such as zeolite beta, MFI, MEL, MTW, MOR, LTL, or FAU, and ZSM-5. Another example of a suitable zeotype material is TS-1. These various examples of zeotype materials are Lewis acidic mesoporous amorphous materials, and in some cases, preferably have a structural type of MCM-41 or SBA-15.

  The reaction to produce lactic acid from sucrose, glucose and fructose is most likely in batch mode or in a flow reactor at a temperature in the range of about 50 ° C to about 300 ° C, preferably about 100 ° C to about 220 ° C. Preferably, it may be carried out at a temperature in the range of about 140 ° C to about 200 ° C.

  Referring back to the reaction pathway of the present invention, in certain embodiments, the starting compositions described herein may include reactants and solvents. Suitable solvents for use in connection with the reactants described herein include, but are not limited to, water, alcohols (eg, methanol, ethanol, propanol, isopropanol, n-propanol, butanol, isobutanol, n- Butanol, 2-ethylhexanol, isononanol, isodecyl alcohol or 3-propylheptanol), tetrahydrofuran, methylene chloride, toluene, xylene, and any combination thereof. In certain embodiments, the solvent may be in a supercritical state.

  In certain embodiments, the starting composition described herein comprises reactants at a lower limit from about 5%, 10%, 15%, 25% or 50% based on the weight of the starting composition, and an upper limit at the starting composition. May be included at a concentration ranging from about 95%, 90%, 85%, 75% or 50% based on the weight of the composition, provided that the concentration is in the range from any lower limit to any upper limit. Often it includes any subset in between. In certain embodiments, the starting composition described herein has a solvent lower limit of about 5%, 10%, 15%, 25% or 50% based on the weight of the starting composition, and an upper limit of the starting composition. May be included at concentrations ranging from about 95%, 90%, 85%, 75% or 50% by weight, wherein the concentration ranges from any lower limit to any upper limit, during which Any subset in may be included.

  In certain embodiments, when the reactant comprises an ester (eg, an ester of lactic acid), the starting composition described herein has a moisture content at a lower limit of about 1%, 2%, based on the weight of the starting composition, The upper limit may range from 3%, or 4% up to about 10%, 9%, 8%, 7%, 6%, or 5% based on the weight of the starting composition, where the moisture content is Any subset in the range from any lower limit to any upper limit and between them may be included. By way of example, but not limitation, the starting composition may comprise methyl lactate, butanol and water, the amount of water being from about 1% to about 5% based on the weight of the starting composition.

  In certain embodiments, the starting compositions described herein may be subjected to one or more additional process steps prior to initiating the reaction pathway of the present invention. Examples of additional process steps include, but are not limited to, filtration, acidification, crystallization, pervaporation, electrodialysis, ion exchange, liquid-liquid extraction, and simulated moving bed chromatography. By way of example and not limitation, additional process steps may be used to increase the lactic acid content and remove impurities from the fermentation broth that produces lactic acid.

  Some of the reactions described herein (eg, dehydroxylation reactions and / or esterification reactions) involve contacting the reactants and / or intermediates with a catalyst. In some embodiments, contacting is within the system (eg, introducing the starting composition into the reactor containing the catalyst) and outside the system (eg, mixing the catalyst with the starting composition before introducing the catalyst into the reactor). , And any combination thereof. Systems and processes are described in further detail herein.

  In certain embodiments, a dehydroxylation reaction useful in the reaction pathways of the present invention may include contacting the reactants and / or intermediates with a dehydroxylation catalyst described herein. In certain embodiments, the dehydroxylation catalyst described herein may be a liquid, a solid, or a combination thereof. In certain embodiments, the reactants and / or intermediates may be in the gas phase and / or liquid phase. By way of example, and not limitation, in one embodiment, the dehydroxylation reaction useful in the reaction pathway of the present invention involves contacting the reactants and / or intermediates in the gas phase with a solid dehydroxylation catalyst. You may include that.

Suitable dehydroxylation catalysts for use in connection with the present invention include, but are not limited to, zeolites, modified zeolites, acid catalysts, weak acid catalysts, strong acid catalysts, neutral catalysts, base catalysts, ions, in certain embodiments. Exchange catalysts, zeolites, solid oxides, etc., and any combination thereof may be included. In certain embodiments, preferred dehydroxylation catalysts may include, but are not limited to, L-type zeolites and / or modified zeolites. As used herein, zeolite refers to a series of microporous solid aluminosilicate membranes known as “Molecular Sieves”. Zeolite is represented by the general molecular formula: M _{x / n} [(ALO ₂ ) _x (SiO ₂ ) _y ] zH ₂ O, where n is the charge of the metal cation (M), where M is usually Na ⁺ , K ⁺ Or Ca ²⁺ and z is the number of moles of highly variable hydration water. An example of a zeolite of the _formula: Natororaito represented by _{Na 2 Al 2 Si 3 O 10} · 2H 2 O (Natrolite). As used herein, the term “modified zeolite” refers to a zeolite that has been modified by (1) impregnation with inorganic salts and / or oxides, and / or (2) ion exchange.

  Zeolites are thought to contain channels (also known as gaps or pores) that are occupied by cations and water molecules. Without being bound by theory, it is believed that the dehydroxylation reaction performed in the presence of zeolite preferentially occurs in the zeolite channel. Thus, it is believed that the dimensions of the channel affect, among other things, the diffusion rate of chemicals through it, thereby affecting the selectivity and conversion efficiency of the dehydroxylation reaction. In certain embodiments, the diameter of the channel of the zeolite catalyst suitable for use in conjunction with the dehydroxylation reaction disclosed herein ranges from about 1 to about 20 mm, more preferably from about 5 to about 10 mm, Any subset in between may be included.

  Zeolites suitable for use as the dehydroxylation catalyst described herein may be derived from natural materials and / or may be chemically synthesized. Furthermore, zeolites suitable for use as the dehydroxylation catalyst described herein, in certain embodiments, have a crystal structure equal to L-type zeolite, Y-type zeolite, X-type zeolite, and any combination thereof. You may have. Different types of zeolites such as A, X, Y and L differ from each other in terms of their composition, pore volume, and / or channel structure. A-type and X-type zeolites have a Si / Al molar ratio of about 1 and have an aluminosilicate tetrahedral framework. Y-type zeolite has a Si / Al molar ratio of about 1.5 to about 3.0 and has a topological framework similar to that of X-type zeolite. L-type zeolite has a Si / Al molar ratio of about 3.0, and has a one-dimensional pore size of about 0.71 nm corresponding to a cavity of about 0.48 nm x 1.24 nm x 1.07 nm. Have.

In certain embodiments, the modified zeolite may be produced by subjecting the zeolite to ion exchange. In certain embodiments, a modified zeolite suitable for use as a dehydroxylation catalyst described herein is associated with, but is not limited to, H ⁺ , Li ⁺ , Na ⁺ , K ⁺ , Cs ⁺ , Mg ²⁺ , Ca ²⁺ , La ²⁺ , La ³⁺ , Ce ²⁺ , Ce ³⁺ , Ce ⁴⁺ , Sm ²⁺ , Sm ³⁺ , Eu ²⁺ , Eu ^{3+ and the} like, and any combination thereof may have ions . As used herein, “[ion-bonded]-[crystal structure] type zeolite” is used to simplify certain zeolites and / or modified zeolites. For example, what has a potassium ion couple | bonded with the L-type zeolite is simply described as a KL type zeolite. As another example, those having potassium and sodium ions combined with zeolite X are simply described as Na / K-X zeolite. In certain embodiments, the L-type zeolite may be modified by techniques such as calcination, ion exchange, initial wet impregnation, hydrotreatment with steam, any hybrid thereof, and any combination thereof.

  In certain embodiments, a modified zeolite suitable for use as a dehydroxylation catalyst described herein may have more than one cation associated therewith. In certain embodiments, a modified zeolite suitable for use as a dehydroxylation catalyst described herein may comprise a first cation and a second cation, wherein the molar ratio of the first cation to the second cation is about 1: From the lower limit of 1000, 1: 500, 1: 100, 1:50, 1:10, 1: 5, 1: 3, 1: 2, or 1: 1 to about 1000: 1, 500: 1, 100: 1 , 50: 1, 10: 1, 5: 1, 3: 1, 2: 1 or 1: 1, where the molar ratio ranges from any lower limit to any upper limit. , Any subset in between may be included. By way of example, and not limitation, modified zeolites suitable for use as the dehydroxylation catalyst described herein include H / Na-L type zeolites, Li / Na-X type zeolites, in certain embodiments, Na / KY-type zeolite and any combination thereof may be used. As another example, but not by way of limitation, modified zeolites suitable for use as the dehydroxylation catalyst described herein are, in some embodiments, Na / KL type zeolites, Na / KY types. Zeolite and / or Na / K-X type zeolite may be used, and the ratio of sodium ion to potassium ion is about 1:10 or more.

Without being bound by theory, it is believed that in embodiments where at least some H ⁺ ions on the zeolite are exchanged, the catalytic acidity of the resulting modified zeolite will be reduced. The magnitude of the decrease in acidity can be measured with a suitable test. For example, the acidity of the modified zeolite may be measured using ASTM (American Society for Testing and Materials) D4824. Briefly, this test uses the chemisorption of ammonia to measure the acidity of the modified zeolite, where a volumetric system is used to obtain the amount of chemisorbed ammonia.

In some embodiments, the modified zeolite may be one in which the zeolite is impregnated with an inorganic salt and / or oxide thereof. Inorganic salts suitable for use in producing the modified zeolites described herein include, but are not limited to, cations of calcium, sodium, magnesium, aluminum, potassium, etc., and any combination thereof in certain embodiments. And phosphates, sulfates, molybdates, tungstates, stannates, antimonates, and the like, and any combination thereof. By way of example and not limitation, in one embodiment, the modified zeolite comprises a sodium phosphate compound (eg, monosodium phosphate (NaH ₂ PO ₄ ), disodium phosphate (Na ₂ HPO ₄ ), and phosphorus Produced with trisodium acid (Na ₃ PO ₄ )), potassium phosphate compounds, sodium aluminum phosphate compounds (eg, Na ₈ Al ₂ (OH) ₂ (PO ₄ ) ₄ ), and any combination thereof Also good.

  In certain embodiments, a modified zeolite suitable for use as a dehydroxylation catalyst described herein is an inorganic salt and / or its oxide, with a lower limit of about 0.1 millimoles, 0.2 millimoles per gram of modified zeolite. Alternatively, it may be impregnated at a concentration of 0.4 millimoles with an upper limit of about 1.0 millimoles, 0.8 millimoles or 0.6 millimoles per gram of modified zeolite, wherein the concentration is from any lower limit. Any subset in the range up to any upper limit and between them may be included. By way of example and not limitation, an impregnable L-type zeolite suitable for use in conjunction with the dehydroxylation reaction described herein is a Na / KL type zeolite impregnated with a sodium phosphate compound. And the ratio of sodium ions / potassium ions is about 1:10 or more.

  One skilled in the art will appreciate further steps to prepare the modified zeolite by ion exchange and / or impregnation. For example, among other things, drying and / or calcination is required to remove water from the pores and / or convert the salt to its oxide. Moreover, inter alia, proper storage is required to prevent the modified zeolite from being at least partially deactivated during storage. As used herein, the term “calcination” refers to a process in which a zeolite catalyst is subjected to a heat treatment step in the presence of air to remove volatile fractions.

  Suitable acid catalysts for use as the dehydroxylation catalyst described herein may be liquid, solid, or a combination thereof. Examples of liquid acid catalysts suitable for use as the dehydroxylation catalyst described herein include, but are not limited to, sulfuric acid, hydrofluoric acid, phosphoric acid, paratoluenesulfonic acid, and the like, and any of them Combinations are listed.

  In one embodiment, the solid acid catalyst contacts a hydroxide or hydrated hydroxide of a metal belonging to Group IV of the periodic table with a solution containing a sulfur component, and the mixture is about 350 ° C. to about 800 ° C. It can be obtained by calcining between ° C. The solid acid catalyst may have an acidity higher than that of 100% sulfuric acid in certain embodiments. In certain embodiments, the solid acid catalyst has the advantage that, inter alia, it is more catalytic and less corrosive than a liquid acid catalyst, while having the advantage of being easy to remove after the reaction is complete. A catalyst is preferred.

Suitable weak acid catalysts for use as the dehydroxylation catalyst described herein include, but are not limited to, titania catalysts, SiO ₂ / H ₃ PO ₄ catalysts, fluorinated Al ₂ O ₃ (eg, Al ₂ O ₃ HF catalyst), Nb ₂ O ₃ / SO ₄ ^-2 catalyst, Nb ₂ O ₅ H ₂ O catalyst, phosphotungstic acid catalyst, phosphomolybdic acid catalyst, silicomolybdic acid catalyst, silicotungstic acid catalyst, acidic polyvinylpyridine hydrochloride catalyst (Eg, PVPH ⁺ Cl ⁻ (registered trademark) (available from Reilly), hydrated acidic silica catalyst (eg, ECS-3® (available from Engelhard), etc., and any combination thereof. It is done.

Suitable base catalysts for use as the dehydroxylation catalyst described herein include, but are not limited to, ammonia, polyvinyl pyridine, metal hydroxide, Zr (OH) ₄ , general formula: NR ¹ R ² R ³ Wherein R ¹ , R ² and R ³ are independently, but not limited to, hydrogen, hydrocarbons containing 1-20 carbon atoms, alkyls containing 1-20 carbon atoms And / or amines selected from the group of side chains or functional groups, including aryl groups, and the like, and any combination thereof. In one embodiment, ammonium lactate is advantageously used as a reactant for the production of acrylic acid, as ammonium lactate decomposes to release ammonia (base catalyst) and lactic acid when subjected to high temperature treatment. May be.

Solid oxides suitable for use as the dehydroxylation catalyst described herein include, but are not limited to, TiO ₂ (eg, Ti-0720® (available from Engelhard), ZrO ₂ , Al _2. O ₃ , SiO ₂ , ZnO ₂ , SnO ₂ , WO ₃ , MnO ₂ , Fe ₂ O ₃ , V ₂ O ₅ , SiO ₂ / Al ₂ O ₃ , ZrO ₂ / WO ₃ , ZrO ₂ / Fe ₂ O ₃ , ZrO ₂ / MnO ₂ etc., and any combination thereof, notably, the above description relating to ion exchange and impregnation in relation to L-type zeolite should be applied to solid oxide as it is. It is.

A solid dehydroxylation catalyst suitable for use as the dehydroxylation catalyst described herein has, in one embodiment, a large surface area. In certain embodiments, a solid dehydroxylation catalyst suitable for use as a dehydroxylation catalyst described herein may have a surface area of about 100 m ² / g or more. In certain embodiments, a solid dehydroxylation catalyst suitable for use as a dehydroxylation catalyst described herein has a lower limit from about 100 m ² / g, 125 m ² / g, 150 m ² / g or 200 m ² / g. The upper limit may have a surface area in the range of about 500 m ² / g, 400 m ² / g, 300 m ² / g or 250 m ² / g, wherein the surface area is from any lower limit to any upper limit. Any subset in between and in between may be included.

  In certain embodiments, the dehydroxylation catalyst described herein is present in the dehydroxylation reaction described herein in a molar ratio of catalyst to reactant / intermediate of about 1: 1000 or greater. May be. In certain embodiments, the dehydroxylation catalyst described herein has a molar ratio of catalyst to reactant / intermediate of about 1: 1000, 1: 500, in the dehydroxylation reaction described herein. Or may exist in a range from a lower limit of 1: 250 to an upper limit of about 1: 1, 1:10, or 1: 100, wherein the molar ratio is from any lower limit to any upper limit. Any subset in between and in between may be included.

  In certain embodiments, the dehydroxylation reaction may utilize multiple types of dehydroxylation catalysts described herein. In certain embodiments, the weight ratio of the two dehydroxylation catalysts may be about 1:10 or more. In certain embodiments, the weight ratio of the two dehydroxylation catalysts is from a lower limit of about 1:10, 1: 5, 1: 3, or 1: 1 to about 10: 1, 5: 1, 3: 1, or The range is up to an upper limit of 1: 1, where the weight ratio ranges from any lower limit to any upper limit and may include any subset in between. Those skilled in the art from the disclosure herein should recognize that such weight ratios can be extended to three or more dehydroxylation catalysts as described herein.

  In certain embodiments, dehydroxylation reactions useful in the reaction pathways of the present invention range from a lower limit of about 100 ° C, 150 ° C, or 200 ° C to an upper limit of about 500 ° C, 400 ° C, or 350 ° C. It may be made at a temperature, where the temperature ranges from any lower limit to any upper limit and may encompass any subset in between.

  Polymerization inhibitors are utilized in conjunction with the dehydroxylation reactions described herein to prevent polymerization of α, β-unsaturated carboxylic acids or esters formed during the reaction pathway. Also good. In certain embodiments, the polymerization inhibitor is in the reaction pathway of the present invention, for example, in the starting composition, during the dehydroxylation reaction, during the esterification reaction, and any combination thereof. May be introduced. Examples of the polymerization inhibitor include, but are not limited to, 4-methoxyphenol, 2,6-di-tert-butyl-4-methylphenol, sterically hindered phenol, and the like.

  In certain embodiments, the dehydroxylation reaction of the present invention is in the absence of any of the dehydroxylation catalysts described herein, such as glass, ceramic, porcelain, or metallic materials in the reactor. This can be done in the presence of only an inert solid support. In certain embodiments, supercritical solvents are useful for subjecting the starting composition to the dehydroxylation reaction in the absence of the dehydroxylation catalyst described herein.

  In certain embodiments, esterification reactions useful in the reaction pathways of the present invention involve contacting the reactants and / or intermediates with an alcohol (as a reactant and / or solvent) and an esterification catalyst as described herein. Including.

In certain embodiments, the esterification reaction may be performed in the presence of an alcohol as a solvent and / or reactant. In certain embodiments, examples of suitable alcohols include, but are not limited to, alkyl alcohols (eg, C ₁ -C ₂₀ alcohols) (eg, methanol, ethanol, propanol, isopropanol, n-propanol, butanol, isobutanol, n-butanol, 2-ethylhexanol, isononanol, isodecyl alcohol, or 3-propylheptanol), aryl alcohol (eg, benzyl alcohol, etc.), cyclic alcohol (eg, cyclohexanol, cyclopentanol, etc.), and their Any combination is mentioned.

  In certain embodiments, a fermentation broth described herein containing a salt of an α-hydroxycarboxylic acid described herein (eg, ammonium lactate) may be used as a reactant for an esterification reaction. Good. The use of such salts may require, for example, a two-stage esterification reaction consisting of decomposing ammonium lactate into ammonia and lactic acid, and then reacting the lactic acid with the alcohols described herein. Since both steps of this esterification reaction are reversible and may reach equilibrium, in certain embodiments, excess amounts of reactants may be used and / or the reverse reaction is minimized and overall yield is achieved. The product may be removed continuously to increase the

In certain embodiments, the esterification reactions described herein may be performed, inter alia, in a batch process or a reactive distillation process. An esterification catalyst may be used to improve the efficiency of the esterification process in the esterification reactions described herein, including the processes described above. In certain embodiments, the catalyst may be a homogeneous catalyst or a heterogeneous catalyst. Homogeneous catalysts suitable for improving the rate of the esterification process of the present invention include, in certain embodiments, but are not limited to strong mineral acids, strong organic acids, and any combination thereof. In certain preferred embodiments, the homogeneous catalyst for use in conjunction with the esterification reactions described herein may be hydrochloric acid. Heterogeneous catalysts suitable for improving the rate of the esterification process of the present invention include, but are not limited to, cationic resin catalysts such as AMBERLYST-15 (cross-linked styrene available from Rohm and Haas, in some embodiments). Strong acid, sulfonic acid, macroethicular polymer resins) based on divinylbenzene copolymers. In certain embodiments, the esterification catalyst described herein may comprise a mixture of a tin salt and an aluminate, wherein the tin salt is capable of reacting with an aluminum salt to form tin aluminate. And / or tin ions may be provided. In certain embodiments, the esterification catalyst described herein may comprise a mixture of tin salt, aluminate, and refined sand. In certain embodiments, the esterification catalyst described herein may comprise CO ₂ gas.

  The rate of the esterification reaction may be varied by a variety of different methods. For example, increased catalyst concentration, increased alcohol / lactic acid ratio, and / or increased temperature may be used to increase the esterification rate. Those skilled in the art who have benefited from the disclosure herein will recognize that consideration should be given to changing the rate of the esterification reaction, e.g. increasing the temperature may cause volatile reactants such as certain alcohols to be While evaporating, this can be improved, for example, using a cooler.

  In certain embodiments, the pressure of the esterification reaction described herein may range from about 1 atmosphere to about 10 atmospheres. For example, such pressure is sufficient to maintain the ammonium lactate and alcohol in the reaction mixture in a liquid phase.

  In certain embodiments using an ammonium lactate reactant, the molar ratio of alcohol: ammonium lactate in the esterification reaction is about 1: 1 to about 10: 1, more preferably about 1: 1 to about 5: 1. , Any subset in between may be included.

In certain embodiments, the efficiency of the esterification reaction may be affected by the amount of water present. In certain embodiments, a desiccant may be used in the esterification reactions described herein to reduce the water content. In certain embodiments, a desiccant may be used to extract water from the gas phase during alcohol recovery. In certain embodiments, the desiccant may act to adsorb and absorb water on the desiccant. Preferred desiccants do not absorb alcohol, especially the alcohol used in the esterification reaction. In certain embodiments, the desiccant may be an inert porous material. Examples of desiccants include, but are not limited to, diatomaceous earth, molecular sieves, zeolites, etc., and any combination thereof. Commercially available materials with surface areas between approximately 12 cm ² / g and ²⁰ cm ² / g are also suitable for use as desiccants in certain embodiments.

  Adjustment of the moisture content during the esterification reaction may also be achieved and / or enhanced by using a hydrophilic pervaporation membrane. The use of pervaporation membranes during the esterification reaction is advantageously, but not limited to, helping to adjust the moisture content, minimizing the reverse reaction, and helping to separate the lactate esters by distillation. A plurality of functions can be provided.

  Adjusting the water content during the esterification reaction may be achieved and / or enhanced by using an azeotropic agent, such as benzene.

  In certain embodiments, the items described above may be combined and used to adjust the moisture content during the esterification reactions described herein.

  In certain embodiments utilizing an ammonium lactate reactant, ammonia may be released during the esterification reaction. In certain embodiments, the esterification reaction may be performed at an elevated temperature with reflux, and an inert gas may be used to remove ammonia from the cooler. In certain embodiments, the ammonia released during downstream processing of the fermentation broth containing ammonium lactate is condensed, compressed, and recycled to the fermentation vessel as an alkaline source to maintain the pH of the microbial growth medium. obtain.

  On an expanded scale, in one embodiment, reactive distillation over a resin esterification catalyst was used to minimize the reverse reaction of the esterification reaction described above, thereby increasing the theoretical yield close to 100%. Purity esters can be produced. In certain embodiments, lactic acid is dissolved (or dispersed) in alcohol and then passed through the reaction zone of the packed bed of esterification catalyst. The product stream from the outlet of the reaction zone (containing excess alcohol and the desired end product) can then be fed to a distillation column to separate and purify the ester formed. Good. High boiling lactic acid esters can in some embodiments be separated from the alcohol by fractional distillation.

  In certain embodiments, the esterification catalyst described herein may be a liquid, a solid, or a combination thereof. In certain embodiments, the reactants and / or intermediates may be in the gas phase and / or liquid phase. In certain embodiments, esterification catalysts suitable for use in conjunction with the reaction pathways of the present invention include, but are not limited to, ion exchange resins, aluminum silicate compounds (eg, zeolites and / or modifications described herein). Zeolite) and the like, and any combination thereof.

  Under certain circumstances, the esterification reaction may be performed without an external catalyst. An esterification reaction without an external catalyst is preferred. As used herein, the term “external catalyst” is added to the chemical reaction from an external source to reduce the activation energy required for the chemical reaction and improve the overall rate of the chemical reaction. Chemical substance. The term “external catalyst” is used to distinguish a situation in which some of the substrates of a chemical reaction may act as a catalyst. The esterification reaction is, in one embodiment, in International Patent Application No. PCT / US11 / 50707 (Title of Invention, “Catalytic Dehydration of Lactic Acid and Lactic Acid Esters”, which is incorporated herein by reference in its entirety). It may be carried out without adding any external catalyst as described in detail. For example, in certain embodiments, the fermentation broth may be heated to about 100 ° C. in the presence of a suitable alcohol, without the addition of any external catalyst, to achieve lactate ester formation.

  Examples of ion exchange resins suitable for use in conjunction with the esterification reactions described herein include, in some embodiments, but not limited to, AMBERLYST® products, such as AMBERLYST® 70 (Strong acid ion exchange resin available from Rohm and Haas and Dow Chemicals).

  In certain embodiments, the esterification reactant and the dehydroxylation reactant may be used in the same reaction vessel to enable the simultaneous reaction pathway of the present invention (eg, reaction pathway 4 in FIG. 1).

  In certain embodiments, the esterification reactant and dehydroxylation reactant may be used in a series of two different reaction vessels to perform the sequential reaction pathway of the present invention (eg, reaction pathway 1 or 2 in FIG. 1). . Also, the dehydroxylation reaction and the esterification reaction can be performed sequentially in the same reactor. For example, the reaction may be such that the top of the reactor chamber contains an esterification catalyst, the bottom of the reactor chamber contains a dehydroxylation catalyst, and the two catalysts are separated by a central inert material. Path 1 may be implemented. The reactants may be introduced together with a suitable alcohol, in some embodiments, to the top of the reactor chamber. As the reactants pass through the esterification catalyst, the reactants are esterified, and the ester so formed passes through the inert material and reaches the bottom of the reactor chamber, where a dehydroxylation reaction takes place and α An ester of .beta.-unsaturated carboxylic acid, such as a lactic acid reactant, leads to the formation of an acrylate ester.

  In certain embodiments, the dehydroxylation catalyst may occupy the upper portion of the reaction vessel and the esterification catalyst may occupy the lower portion of the reaction vessel, during which there are inert materials that are useful for carrying out reaction pathway 2. For example, reactants are fed to the top of the reactor, and then the α, β-unsaturated carboxylic acid produced at the top of the reaction vessel passes through the inert material and enters the bottom of the reaction vessel, where α, β -Contact with an esterification catalyst and an alcohol to produce an ester of an unsaturated carboxylic acid, and the produced ester may be collected at the bottom of the reactor. In certain embodiments, the alcohol may be in the gas phase. In embodiments where the dehydroxylation catalyst and esterification catalyst are the same, it is optional to load the catalyst in both the top and bottom of the reactor and place an inert material therebetween.

  In certain embodiments, the esterification reaction and dehydroxylation reaction may occur simultaneously in the same reaction vessel as described in Reaction Path 4. In some embodiments, to achieve a simultaneous reaction, a reactant containing the desired alcohol may be introduced at the top of the reaction vessel and the corresponding ester of the α, β-unsaturated carboxylic acid collected at the bottom of the reaction vessel. Good.

  In certain embodiments, aluminum silicate compounds (eg, zeolites and / or modified zeolites) may function as both esterification and dehydroxylation catalysts. In certain embodiments, a catalyst that functions as both an esterification and dehydroxylation catalyst is a sequential reaction pathway of the present invention (eg, Reaction Paths 1 and 2 in FIG. 1) or a simultaneous reaction pathway of the present invention (eg, FIG. 1). May be used in the reaction route 4).

  In certain embodiments, esterification reactions useful in the reaction pathways of the present invention may range from a lower limit of about 50 ° C, 100 ° C, 150 ° C, or 200 ° C to an upper limit of about 500 ° C, 400 ° C, or 350 ° C. It may be performed at a temperature in the range, where the temperature ranges from any lower limit to any upper limit and may encompass any subset in between.

  In certain embodiments, the reaction pathways of the present invention may be used to produce α, β-unsaturated carboxylic acids or esters thereof. Examples of α, β-unsaturated carboxylic acids or esters thereof include, but are not limited to, acrylic acid, alkyl esters of acrylic acid (eg, methyl acrylate and butyl acrylate), and any combination thereof. Can be mentioned.

  Surprisingly, the use of butyl lactate in the starting composition reduces the formation of undesirable by-products that are observed with the use of other alkyl lactates such as methyl lactate, with butyl lactate preferentially over butyl acrylate. It was found to be converted to acrylic acid.

  In certain embodiments, the reaction pathway of the present invention may produce an aldehyde (eg, acetaldehyde). Thus, the reaction pathway may further include an oxidation reaction if desired to convert acetaldehyde to acetic acid.

  In certain embodiments, the reaction pathways of the present invention may be about 40% or more, in some embodiments about 50% or more, in some embodiments about 55% or more, in some embodiments about 60% or more, certain implementations. In some embodiments, greater than or equal to about 65%, in certain embodiments greater than or equal to about 70%, in certain embodiments greater than or equal to about 75%, in certain embodiments greater than or equal to about 80%, and in certain embodiments greater than or equal to about 85%. It may have a conversion efficiency of about 90% or more in embodiments, in some embodiments about 95% or more, in some embodiments about 98% or more, or in some embodiments about 99% or more.

  In some embodiments, the selectivity of the reaction pathway of the present invention is 40 mol% or more of the product, in some embodiments 50 mol% or more, in some embodiments 55 mol% or more of the product. At least 60 mol% of the product, in some embodiments at least 65 mol% of the product, in some embodiments at least 70 mol% of the product, in some embodiments at least 75 mol% of the product In embodiments, more than 80 mol% of the product, in some embodiments more than 85 mol% of the product, in some embodiments more than 90 mol% of the product, in some embodiments more than 95 mol% of the product. An α, β-unsaturated carboxylic acid and / or an amount thereof in an embodiment of 98 mol% or more of the product and in some embodiments 99 mol% or more of the product. May result in the formation of esters.

  The conversion efficiency and / or selectivity of the reaction path can be determined, inter alia, by controlling the temperature at which the catalyst is calcined, the composition of the dehydroxylation and / or esterification catalyst, the concentration of reactants and / or intermediates, It should be appreciated that and / or depending on the contact time of the reactants and / or intermediates with the dehydroxylation and / or esterification catalyst.

  In certain embodiments, it has been observed that reactor smelting techniques can adversely affect acrylic acid selectivity in lactic acid dehydroxylation reactions. Without being bound by theory, it is believed that the supply of lactic acid causes corrosion of the reactor wall and leaching of metal components from the reactor wall. For example, when a stainless steel reactor is used for the dehydroxylation reaction, metal components such as nickel, chromium, iron, etc. leach into the product stream and / or accumulate on the dehydroxylation catalyst, That can be detected using, for example, inductively coupled plasma (ICP) analysis. The leached metal may act as a catalyst with the ability to form by-products. For example, nickel released from a stainless steel reactor wall may act as a hydrogenation catalyst and form propionic acid from acrylic acid. Similarly, iron released from stainless steel reactor walls may function as a decarboxylation catalyst, leading to the formation of acetaldehyde. Also, some of the components leached from the reactor wall may result in a polymerisation of lactic acid and acrylic acid. Thus, in certain embodiments, the reactor material may be selected to be resistant to corrosion by either feedstock or products formed through catalytic dehydroxylation reactions. Examples of suitable reactor materials that reduce undesirable catalysis include, but are not limited to, titanium, silane-treated stainless steel, quartz, and the like. Such reactors with low levels of corrosive action can provide high selectivity for acrylic acid and low byproduct formation ability.

  By way of example, and not by way of limitation, as with reaction pathways 2 and 3 shown in FIG. 1, certain embodiments may employ a starting composition described herein with a dehydroxylation catalyst comprising an L-type zeolite. It may include first performing a dehydroxylation reaction by contacting, thus producing an α, β-unsaturated carboxylic acid and / or ester thereof. Once the α, β-unsaturated carboxylic acid is produced, one embodiment performs an esterification reaction by contacting the α, β-unsaturated carboxylic acid with an esterification catalyst and an alcohol, and thus α, β -May further comprise producing an unsaturated carboxylic acid ester. Specifically, in certain embodiments, the starting composition may include lactic acid, and then the product of the dehydroxylation reaction may include acrylic acid, and if so, the product of the esterification reaction is acrylic. An acid ester may be included.

  As another example, but not by way of limitation, as with Reaction Path 1 shown in FIG. 1, certain embodiments may be employed to produce a starting composition comprising a carboxylic acid derivative as described herein as an esterification catalyst and an alcohol. The esterification reaction is first carried out by contacting with an ester, thereby producing an ester derivative; the dehydroxylation reaction is then carried out by contacting the ester derivative with a deesterification catalyst comprising L-type zeolite, whereby α , Β-unsaturated carboxylic acid esters may be generated. Specifically, in certain embodiments, the starting composition may include lactic acid, then the product of the esterification reaction may include a lactic acid ester, and the product of the subsequent dehydroxylation reaction may include an acrylate ester. May be included.

  By way of further example, but not by way of limitation, as with reaction pathway 4 shown in FIG. 1, certain embodiments may be used to form a starting composition comprising a carboxylic acid derivative as described herein in alcohol and L-form. It may include simultaneously performing a dehydroxylation reaction and an esterification reaction by contacting with a catalyst containing a zeolite, thereby producing an α, β-unsaturated carboxylic acid ester. Specifically, in certain embodiments, the starting composition may include lactic acid, and the product of the reaction that then undergoes dehydroxylation and esterification simultaneously may include an acrylate ester.

  Any suitable system may be used in conjunction with the implementation of the reaction pathway of the present invention. In certain embodiments, a system suitable for use in conjunction with carrying out the reaction pathway of the present invention includes a reactor and optionally contains at least one preheater (eg, starting composition, solvent, reactant, etc.). A preheater for preheating), pumps, heat exchangers, coolers, material handling devices, etc., and any combination thereof. Examples of suitable reactors include, but are not limited to, batch reactors, plug flow reactors, continuous stirred tank reactors, packed bed reactors, slurry reactors, fixed bed reactors, fluidized bed reactors. Etc. The reactor may be either single-stage or multi-stage in certain embodiments. Furthermore, the reaction pathways of the present invention may be carried out in certain embodiments, batchwise, semi-continuously, continuously, or combinations thereof.

  As described above, the reaction pathway may be carried out in the liquid phase and / or the gas phase. Accordingly, a carrier gas (eg, argon, nitrogen, carbon dioxide, etc.) may be utilized in conjunction with the reaction pathways and / or systems described herein. In certain embodiments, the reaction pathway or a portion thereof may be performed in the liquid phase and the gas phase, and in certain embodiments, it may be a substantially single inert gas (eg, the carrier gas is a single Carrier gas accounts for more than about 90%) or a mixture of a plurality of inert gases. In certain embodiments, the reaction pathway or a portion thereof may be performed in liquid and gas phases, and in certain embodiments, it is substantially carbon dioxide (eg, the carrier gas is about 90% carbon dioxide). May account for more).

  In certain embodiments, the reaction pathways of the present invention may have a weight space velocity (“WHSV”) of about 0.2 / hour to about 1.5 / hour, more preferably about 0.5 / hour to about 1.2 / hour. ).

  In certain embodiments, the products of the reaction pathways of the present invention include α, β-unsaturated carboxylic acids and / or esters thereof and other components (eg, solvents, polymerization inhibitors, byproducts, unreacted products). Reactants, dehydroxylation catalysts, and / or esterification catalysts). Accordingly, the product of the reaction pathway of the present invention may be divided into product components (including product mixtures) and / or purified. In certain embodiments, the solvent may be separated from the product of the reaction pathway of the present invention and recycled for reuse. Solvent recycling may advantageously reduce waste production and reduce the cost of producing α, β-unsaturated carboxylic acids and / or esters thereof.

  Suitable methods for separation and / or purification include, but are not limited to, distillation, extraction, reactive extraction, adsorption, absorption, stripping, crystallization, evaporation, sublimation, diffusion separation, adsorptive bubble separation, membrane separation, fluid Particle separation and the like, and any combination thereof.

  One of ordinary skill in the art having benefit from this disclosure should further recognize that at least some of the various dehydroxylation and / or esterification catalysts described herein can be produced either in situ or ex situ. It is. For example, in certain embodiments, the zeolite and / or modified zeolite may be regenerated at an elevated temperature in the presence of oxygen (eg, oxygen diluted in air or an inert gas).

  In order to facilitate a further understanding of the invention, preferred or representative embodiments are shown in the following examples. The following examples should not be construed as limiting or limiting the scope of the invention in any way.

Example I.1. Abbreviations and Formulas Table 1 provides several formulas used throughout the examples.

II. Catalysts Several catalysts were prepared in the following manner. The catalysts used in the examples presented herein were obtained from either WR Grace Company, USA or TOSOH USA, Inc. and subjected to appropriate chemical modifications as needed.

“HY type zeolite” was prepared as 1/16 inch pellets with a SiO ₂ : Al ₂ O ₃ ratio of 6: 1 and a Na ₂ O content of 0.28 wt%. The H-Y zeolite was calcined at 500 ° C. for 3 hours and held in a sealed vial in a desiccator until use.

The "Na-Y-type _zeolite", SiO 2: _Al 2 _{O 3} is 5: 1 ratio, the content of Na ₂ O is 13 wt%, were prepared as extrudates of 1/16-inch. Na-Y zeolite was calcined and stored as described for H-Y zeolite.

“K ⁴ / Na—Y type zeolite” was prepared by converting Na—Y type zeolite four times with KCl aqueous solution. Na-Y type zeolite (ground and sieved to a particle size of 20-60 mesh) (30 g) is slowly added to a 2M solution of KCl (150 mL) and the suspension is added to a Rotavapor on a 60 Stir for 2 hours at ° C. The flask was removed and the supernatant was replaced with another replacement fresh KCl solution. The same operation was repeated twice more. The resulting sample was washed several times until Cl ⁻ was exhausted, initially dried at 30 ° C. and 60 ° C. at 2-3 mmHg for 2 hours. The catalyst was then transferred to a vacuum oven, held at 110 ° C. overnight, calcined at 500 ° C. for 3 hours, and stored in a desiccator until use.

A “KL type zeolite” was prepared such that the ratio of SiO ₂ : Al ₂ O ₃ was 7: 9 and contained 14.4% K ₂ O on a dry basis. The KL type zeolite was ground and sieved through a 20-60 mesh diameter. The zeolitic material was calcined as described for the HY type zeolite above.

“Li / KL type zeolite” was prepared by subjecting KL type zeolite (15 g) to a single treatment with LiCl 1M solution (150 mL) at 30 ° C. overnight. The sample obtained was washed several times until Cl ⁻ was eliminated, then dried at 30 ° C. and 60 ° C. at 2-3 mmHg for 4 hours. In addition, the catalyst was dried in a vacuum oven at 110 ° C. overnight and finally calcined at 450 ° C. for 3 hours.

“Na / KL type zeolite” was prepared by slowly adding KL type zeolite (15 g) to a 1M aqueous solution of NaCl (200 mL). The suspension was stirred at 30 ° C. for 6 hours. After removing the supernatant, the solid was washed several times until Cl ⁻ disappeared. After drying under reduced pressure, the catalyst was calcined at 450 ° C. for 3 hours as described above for HY type zeolite.

A “Na ² / KL type zeolite” was prepared in the same way as the Na / KL type zeolite, except that after the first exchange, the zeolite was treated with a fresh NaCl solution of the second part. .

“Na ³ / KL type zeolite” is prepared in the same way as the Na ² / KL type zeolite except that after the second exchange, the zeolite is treated with a fresh NaCl solution of the third part. did.

“Na ⁴ / KL type zeolite” is prepared in the same way as the Na ³ / KL type zeolite, except that after the third exchange, the zeolite is treated with a fresh NaCl solution of Part 4. did.

“(7.1% Na ₂ HPO ₄ ) / KL type zeolite” was prepared by an initial wet method using KL type zeolite. According to this method, Na ₂ HPO ₄ 7H ₂ O (solution in deionized water (13 mL) in Na ₂ HPO ₄ (2.164 g)) was slowly added to KL zeolite (13 g). The resulting slurry was held in a sealed beaker for 2 hours. The impregnated solid was then transferred to a normal oven and dried overnight at 120 ° C.

“(7.1% Na ₂ HPO ₄ ) / Na ³ / KL type zeolite” was converted into (7.1% Na ₂ HPO ₄ ) / KL type using Na ³ / KL type zeolite. Prepared by the same operation as zeolite.

“(2.13% Na ₂ HPO ₄ ) / KL zeolite” was used in the same manner as (7.1% Na ₂ HPO ₄ ) / KL zeolite using a smaller amount of Na ₂ HPO _4. It was prepared by.

“(3.55% Na ₂ HPO ₄ ) / KL type zeolite” was operated in the same manner as (7.1% Na ₂ HPO ₄ ) / KL type zeolite with a smaller amount of Na ₂ HPO _4. It was prepared by.

“(2.13% Na ₂ HPO ₄ ) / KL type zeolite” was operated in the same manner as (7.1% Na ₂ HPO ₄ ) / KL type zeolite using a larger amount of Na ₂ HPO _4. It was prepared by.

III. Reaction protocol Reaction protocol I (continuous gas phase dehydroxylation of methyl lactate)
The reaction is described in detail in a fixed bed reactor system in which the starting composition (described in detail in the following examples) is a solid catalyst in the gas phase (described in the following examples). ) Was carried out by passing over. A detailed schematic diagram of the reactor system is shown in FIG. 2 and is further described herein. The reactor was made of ½ inch × 12 inch stainless steel tubing and held three 10 μm stainless steel filters in the bottom section serving as a support for the catalyst bed. The middle section of the reactor was packed with 10.5 mL of catalyst using a GC column packed vibrator. The top section of the reactor has space to accommodate four identical suction filters, thereby providing a porous stainless steel contact area (8 mL) for pre-evaporation and / or gas-liquid mixing Is done. The reactor tube was placed in a column heater (Flatron CH 30) incorporating a high power heating tape (Omega, 470W, Part # STH051-060). The temperature of the reactor was monitored with a thermoelectric thermometer attached near the outer wall of the reactor tube and controlled with a temperature controller (model M 260, J-KEM Scientific). The liquid hourly space velocity ("LHSV") is between about 0.50 / hour and about 1.10 / hour (based on a catalyst volume of 10.5 mL and a liquid flow rate of about 0.1 to about 0.2 mL / min). It fluctuated. The nitrogen flow rate varied between 4.4 and 5.6 mL / min.

Reaction protocol II (continuous gas phase dehydroxylation of butyl lactate)
The reaction was carried out with the same procedure and system as described above for methyl lactate dehydroxylation. The liquid hourly space velocity (“LHSV”) remained constant at 1.2 / hour (based on 5 mL catalyst volume and 0.1 mL / min liquid flow rate). The nitrogen flow rate was also kept constant at 5.0 mL / min.

Reaction protocol III (continuous gas phase dehydroxylation of lactic acid)
The reaction was carried out with the same procedure and system as described above for methyl lactate dehydroxylation. The reactor was made of 5/16 "x 6" stainless steel tubing and the catalyst was held between two plugs of silica sand (50-70 mesh particle size). In this series of experiments, the liquid hourly space velocity ("LHSV") is based on about 0.48 / hour to about 2.4 / hour (0.04 cc / min flow rate and catalyst capacity in the range of about 1 cc to about 7 cc). ). Specific reaction parameters are listed herein in each additional example.

Fixed Bed Reactor System With reference to FIG. 2, the system is treated as consisting of four separate sections AD. Section A is a gas control section that includes two individual channels for alternative gas and purge gas. The alternative gas channel provides pre-catalyst gases, such as ammonia and carbon dioxide, while the purge gas channel provides a nitrogen flow in the range of 2-30 mL / min. As shown in Section A, the purge gas channel and the alternate gas channel each have two-way on / off valves 2-1 and 2-2 individually and mass flow controllers 1 and 2, respectively. Further, the purge gas channel includes a three-way valve 3-1.

  Section B provides liquid phase handling and consists of two circuits. The first circuit is used to introduce liquid reactants into the system and includes a transfer flask 4-1 and a reactant reservoir 4-2. The reactants in the transfer flask 4-1 can be transferred to the reactant flask 4-2 by the positive pressure of the inert gas. In this system, the reservoirs are all pressurized to 8 psi with nitrogen, allowing smooth operation of the pump 5. Furthermore, the reactant flask 4-2 was placed on a balance, and the added reactant was subjected to continuous monitor observation over time. The second circuit is used to introduce liquid solvent into the system and includes a solvent flask 4-3. Reactants and / or solvents are transferred to pump 5 via 3-way selective valve 3-2. Liquid reactant and / or solvent is then directed to either reactor 7 or reactant reservoir 4-2 by three-way valves 3-3 and 3-4, respectively. This setup allows the solvent used to purge the various transfer lines or deliver the reactants to the reactor 7.

  Section C is a reactor 7 as described above with a column heater that controls the temperature. Another thermoelectric thermometer may be attached to the reactor to accurately monitor the temperature of the reactor.

  Section D consists of a spring-loaded back pressure regulator 8, an in-line cooler 9, and a collection flask 11 (in this system a jacketed glass flask). The collection flask 11 temperature was maintained at 4 ° C. in order to effectively retain all low boiling products. A dry eye strap 12 was placed after the collection flask 11 to quench all low boiling products.

IV. Experimental Hydroxylation of Lactic Acid in Aqueous Solvent The starting composition of 40% lactic acid / 60% water was reacted in the gas phase with various catalysts listed in Table 2 (KL zeolite for 2 hours at 320 ° C). The reaction was carried out at 320 ° C. for 4 hours according to the reaction protocol III described above. In this section, reaction time refers to the time for the starting composition to pass over and / or through the catalyst particle bed, as opposed to a static starting material and a sample of catalyst particles. Furthermore, the conversion and selectivity measurements are based on a sample of one product collected over the reaction time described above, as opposed to all products collected over the entire reaction time.

As shown in Table 2, Y-type zeolite exhibits high lactic acid conversion with very low acrylic acid selectivity of less than 13%. In contrast, both KL type zeolite and Na ³ / KL type zeolite show good lactic acid conversion of about 65% and high acrylic acid selectivity of about 50%. Li / KL type zeolite increased lactic acid conversion but produced acetaldehyde more significantly. On the other hand, impregnated zeolite, ie 7.1% Na ₂ HPO ₄ / KL type zeolite, increased lactic acid conversion and reduced acetaldehyde product compared to the parent KL type zeolite.

Dehydroxylation of lactic acid in aqueous solvent The starting composition of 40% D, L-lactic acid / 60% water and 100 ppm of the polymerization inhibitor 4-methoxyphenol is listed in Table 3 in the gas phase. The reaction was carried out at 320 ° C. for 4 hours according to the above reaction protocol III. As can be seen from the results shown in Table 3, among the catalysts tested in this experiment, HSZ-500® KOD1S, an L-type zeolite catalyst, had a low conversion level, but acrylic acid had a high selectivity. Had.

Dehydroxylation of lactic acid in aqueous solvent The starting composition of 40% D, L-lactic acid / 60% water and 100 ppm of the polymerization inhibitor 4-methoxyphenol is listed in Table 4 in the gas phase. The reaction was carried out at 320 ° C. for 4 hours according to the above reaction protocol III.

As shown in Table 4, zeolites modified with smaller cations have high conversion but the selectivity for acrylic acid appears to be adversely affected by large and small cations. Thus, in some embodiments, zeolites modified with sodium ions are preferred.

Dehydroxylation of lactic acid in aqueous solvent-impregnation amount (1)
A starting composition of 40% by weight lactic acid in water was reacted at 330 ° C. in the gas phase using the various catalysts listed in Table 5 according to reaction protocol III described above.

As shown in Table 5, a gradual increase in the amount of Na ₂ HPO ₄ supported on the base KL zeolite system improves both conversion and selectivity, while acetaldehyde is a good propionic acid. The by-product of was reduced. In this catalyst system, it is considered that a load of 7.1% is an optimum range for the amount of impregnation of Na ₂ HPO ₄ .

Dehydroxylation of lactic acid in aqueous solvent-impregnation amount (2)
A starting composition of 40 wt% D, L-lactic acid in water was reacted at 340 ° C. in the gas phase using the various catalysts listed in Table 6 according to reaction protocol III described above.

As shown in Table 6, impregnation appears to result in a highly conversion catalyst system. However, the amount of Na ₂ HPO ₄ supported on the base Na ³ / KL zeolite system appears to have an effect on conversion and selectivity while significantly reducing the by-product acetaldehyde. . In this catalyst system, it is considered that a load of 7.1% is an optimum range for the amount of impregnation of Na ₂ HPO ₄ .

Dehydroxylation of lactic acid in aqueous solvent-catalyst stability A starting composition of 40% lactic acid / 60% water was prepared in the gas phase using the various catalysts listed in Table 7 above, reaction protocol III described above. And reacted at 340 ° C. for 4 hours. As an indication of the tendency of each catalyst to lose activity over time, the product was analyzed over time in a 4 hour reaction.

As shown in Table 7, both KL zeolite and Na ³ / KL type zeolite gradually decrease in activity and selectivity over time, but not so much with Na ³ / KL type zeolite. is not. In contrast, impregnation with Na ₂ HPO _{4 as shown} in 7.1% Na ₂ HPO ₄ / KL zeolite and 7.1% Na ₂ HPO ₄ / Na ³ / KL zeolite catalyst It seems to stabilize both conversion and selectivity. Partial Na exchange and Na ₂ HPO ₄ impregnation (ie, 7.1% Na ₂ HPO ₄ / Na ³ / KL type zeolite) together, with high and stable conversion, against acrylic acid It appears to show a synergistic effect that results in high and stable selectivity.

Dehydroxylation of lactic acid in aqueous solvent-temperature effect Starting compositions of various concentrations of lactic acid ("LA") in water listed in Table 8 and 100 ppm 4-methoxyphenol in the gas phase Then, 7.1% Na ₂ HPO ₄ / Na ³ / KL type zeolite was reacted for 4 hours at various temperatures listed in Table 8 according to the above reaction protocol III.

As shown in Table 8, for the 40% lactic acid starting composition, increasing the temperature resulted in an increase in both conversion and selectivity. Conversely, for 30% and 20% lactic acid starting compositions, increasing the temperature increases the conversion, but decreases the selectivity for acrylic acid, and for samples with a starting lactic acid concentration of 20%, the temperature is increased to 340 When raised to ° C, the decrease in selectivity was really dramatic.

Dehydroxylation of Lactic Acid in Aqueous Solvent—Lactic Acid Concentration Effect Starting compositions with starting concentrations of 50% and 60% lactic acid (“LA”) shown in Table 9 were prepared in the gas phase (7.1% The reaction was carried out using Na ₂ HPO ₄ ) / Na ³ / KL type zeolite according to reaction protocol III described above for 5 hours at various temperatures listed in Table 9.

As shown in Table 9, increasing the temperature resulted in an increase in conversion, but the selectivity did not change much with increasing temperature. Furthermore, increasing the starting lactic acid concentration had at least minimal effects at these concentrations on conversion and selectivity at the corresponding temperature.

Dehydroxylation in water solvent of lactic acid - the starting composition of the flow velocity effect of 40% lactic / 60% water of the reactants, in the vapor phase, and Na 3 / ^K-L zeolite, according to the reaction protocol III as described above, The reaction was allowed to proceed at 320 ° C. for 3 hours, whereupon the liquid flow rate of the starting composition was varied to constitute the weight hourly space velocity (“WHSV”) listed in Table 10.

As shown in Table 10, increasing the lactic acid space velocity (ie, increasing the reactant flow rate) results in a decrease in conversion and a significant improvement in acrylic acid selectivity.

Dehydroxylation in water solvent of lactic acid - the starting composition of the flow velocity effect of 40% lactic / 60% water of the carrier gas, in the gas phase, and Na 3 / ^K-L zeolite, according to the reaction protocol III as described above, The reaction was conducted at 320 ° C. for 4 hours, where the argon carrier gas flow rate was varied as listed in Table 11.

As shown in Table 11, increasing the carrier gas flow rate appears to decrease the formation of acetaldehyde and propionic acid while maintaining acrylic acid selectivity.

Dehydroxylation of lactic acid in solvent-Solvent effect The starting composition listed in Table 12 was prepared at 340 ° C according to reaction protocol III described above using Na ³ / KL zeolite in the gas phase. Reacted for hours.

As shown in Table 12, Na ³ / KL type zeolite catalyzes the esterification reaction. Furthermore, while the addition of alcohol to the starting composition has a small effect on conversion, the selectivity to acrylic acid appears to be significantly reduced.

Dehydroxylation of lactic acid in aqueous solvent-effect of catalyst capacity A starting composition of 20% lactic acid / 80% water was combined with 7.1% Na ₂ HPO ₄ / Na ³ / KL type zeolite in the gas phase. The reaction was carried out at 330 ° C. for 4 hours according to reaction protocol III described above, where the capacity of the catalyst in the reactor was varied as listed in Table 13.

As shown in Table 13, increasing the amount of catalyst appears to increase the conversion. However, excess catalyst appears to reduce selectivity.

Dehydroxylation in water solvent of lactic acid - the starting composition of 20% decrease of lactic acid / 80% water of the catalytic activity, in the gas _{phase, 7.1% Na 2 HPO 4 /} Na 3 / K-L -type on zeolite The reaction was carried out at 330 ° C. for 96 hours according to the reaction protocol III described above (FIG. 5). In order to determine the tendency of the catalyst to lose activity over time, the products were each analyzed periodically through a 96 hour reaction.

As shown in FIG. 5, 7.1% Na ₂ HPO ₄ / Na ³ / KL type zeolite has consistent lactic acid conversion and acrylic acid selectivity of about 70% or more over 50 hours.

Dehydroxylation of lactic acid in aqueous solvent-Lactic acid source A starting composition with a lactic acid concentration of 20% or 30% is applied on a 7.1% Na ₂ HPO ₄ / Na ³ / KL type zeolite in the gas phase. The reaction was carried out at 330 ° C. for 4 hours according to the above reaction protocol III. Lactic acid was from two sources (1) synthetic lactic acid (available from Sigma-Aldrich, TCI or Alfa Aesar) and (2) biologically derived lactic acid (available from ADM Corporation). Biological lactic acid was derived by biological fermentation of sugar. Biological lactic acid of two grades (USP-US Pharmacopoeia; FCC-official food chemical collection) was used in this experiment (Table 14).

Dehydroxylation of Butyl Lactate in Butanol-Water Solvent-Catalytic Effect The starting composition of 50% butyl lactate / 45% butanol / 5% water is listed in Table 15 in the gas phase according to reaction protocol II described above. The reaction was carried out at 300 ° C. for 4 hours on various catalysts.

As shown in Table 15, when the amount of Na ⁺ bound to the catalyst increases (that is, when the amount of Na ⁺ exchange increases), the selectivity to acrylic acid, which is an effect also observed with the Li ⁺ exchange catalyst, increases. To increase.

Dehydroxylation of Butyl Lactate in Butanol-Water Solvent—Action of Water The starting composition listed in Table 16 was prepared in the gas phase according to the reaction protocol II described above on Na ³ / KL zeolite over 300 The reaction was carried out at 4 ° C. for 4 hours.

As shown in Table 16, the selectivity of acrylic acid increases with increasing water content in a solvent system containing water. Thus, for these reaction parameters, the optimal range of water content is approximately from about 5 to about 10%, which results in a stable catalytic activity at the test temperature.

Dehydroxylation of Butyl Lactate in Butanol-Water Solvent—Temperature Effect The starting composition of 50% butyl lactate / 45% butanol / 5% water was prepared as described above on the Na ³ / KL type zeolite in the gas phase. The reaction was carried out for 4 hours at the temperatures listed in Table 17 according to the reaction protocol II.

As shown in Table 17, increasing the temperature above 280 ° C seems to increase the conversion of butyl lactate and the selectivity of acrylic acid.

Dehydroxylation of Butyl Lactate in Butanol-Water Solvent-Flow Rate Effect of Reactant A starting composition of 50% butyl lactate / 45% butanol / 5% water is applied in the gas phase over Na ³ / KL type zeolite. Then, the reaction was performed at 300 ° C. for 4 hours according to the reaction protocol II described above. The flow rate of the starting composition was adjusted to give the LHSV listed in Table 18.

As shown in Table 18, increasing LHSV appeared to have a small effect on the selectivity of acrylic acid, but the conversion of butyl lactate decreased. Nevertheless, the optimum LHSV for acrylic acid selectivity appears to be about 2 / hour to about 3 / hour.

Dehydroxylation of lactic acid in aqueous solvent-catalytic activity after regeneration 20% lactic acid / 80% water starting composition was converted into 7.1% Na ₂ HPO ₄ / Na ³ / KL type zeolite in the gas phase Above, the reaction was carried out at 330 ° C. for 96 hours according to reaction protocol III described above (FIG. 6) and regenerated with air at 330 ° C. for 3 hours. The product was analyzed periodically over a 72 hour reaction to measure the catalyst trend for post-regeneration activity. As shown in FIG. 6, steady state conversions of over 70% were successfully regained. However, the selectivity of steady-state acrylic acid has been reduced to about 50% or more because the temperature used for regeneration is lower than that required to burn the coke that is discarded.

Dehydroxylation of Butyl Lactate in Methanol-Water Solvent The starting composition listed in Table 19 was prepared on a Na ³ / KL type zeolite in the gas phase at 300 ° C. according to reaction protocol I described above. Reacted for hours.

As shown in Table 19, the selectivity of acrylic acid increases at high water concentrations. Also, methoxypropionic acid, a by-product, decreased with increasing water concentration.

Dehydroxylation of lactic acid in aqueous solvent-catalytic activity with binders Starting compositions with a lactic acid concentration of 20% were described above in the gas phase on calcined or non-calcined catalysts listed in Table 20. The reaction was carried out at 330 ° C. for 5 hours according to reaction protocol III. The catalyst HSZ-500 (registered trademark) KOD1C (L-type zeolite, available from TOSOH USA, Inc.) was used as such or calcined at 450 ° C. Clay A was used as a binder in this experiment. The clay A binder used in this experiment is different from the silica binder used in any other experiment described herein.

The results shown in Table 20 show that the calcination catalyst compared to the non-calcin catalyst and mixed with Clay A may reduce the selectivity of acrylic acid, although the effect on conversion may be minimal. , Indicates that it can act to increase the by-product acetaldehyde. This may be due to modification of acidic or basic sites on the catalyst during the calcination process.

Dehydroxylation of Lactic Acid in Aqueous Solvent—Effect of Carrier Gas Composition A starting composition containing 20% concentration of lactic acid was prepared in the gas phase using the carrier gas listed in Table 21 in various ways listed in Table 21. The catalyst was reacted for 5 hours at 330 ° C. according to reaction protocol III described above.

The results shown in Table 21 show that the use of carbon dioxide as the carrier gas improved the stable conversion and acrylic acid selectivity with both modified L-type zeolite catalysts tested, especially 7.1% Na ₂ HPO. ₄ / Na-3 ^rd Ex KL suggests that byproduct aldehyde formation is reduced. FIG. 7 shows that for 7.1% Na ₂ HPO ₄ / Na-3 ^rd Ex KL, CO ₂ and argon or as carrier gases for 20% aqueous lactic acid conversion and acrylic acid selectivity over a 100 hour test. Comparative data using nitrogen is shown.

Measurement of stainless steel reactor wall corrosion In this experiment, the degree of corrosion of stainless steel reactor wall by lactic acid was monitored during continuous operation of the stainless steel catalytic reactor L-type zeolite catalyst for 4 days. Observed. An aqueous lactic acid solution (20% w / v) was used as the feed. The reactor was maintained at a temperature of 330 ° C. and nitrogen was used as the carrier gas. The reactor was operated in continuous mode and acrylic acid was collected daily. At the end of the fourth day, the daily collected acrylic acid fraction, lactic acid feed, fresh catalyst, spent catalyst were analyzed for the level of each metal present in each of these samples shown in Table 22. The results show that the L-type zeolite catalyst retains a significant concentration of metal that exudes from the stainless steel reactor in the dehydroxylation reaction.

In this lactic acid dehydroxylation experiment, acetaldehyde and propionic acid were also detected as by-products, and their molar selectivity was also measured during the 4 day experiment. As suggested by the results shown in Table 23, the molar selectivity of acetaldehyde and propionic acid increased during the 4-day experiment, thereby reducing the selectivity for acrylic acid.

  The above examples suggest that multiple catalysts based on L-type zeolites and modified zeolites can be used to produce α, β-unsaturated carboxylic acids and / or their esters.

  Accordingly, the present invention is well adapted to obtain the objects and advantages mentioned as well as those inherent to the present invention. The specific embodiments described above are exemplary only, and the invention may be modified and implemented in an equivalent manner, although it will be apparent to those skilled in the art who would benefit from the techniques disclosed herein. Furthermore, except as set forth in the appended claims, it is not intended to limit the construction or design shown herein to the details thereof. It is therefore evident that the particular specific embodiments described above may be altered, combined and modified and all such variations are considered within the scope and spirit of the invention. The invention disclosed herein by way of example may be in the absence of any element specifically disclosed herein and / or any element disclosed herein. Can be done appropriately. Although the compositions and methods are described in terms of “comprising”, “containing” or “including” various components or steps, the compositions and methods are essentially “from” the various components or steps. It can also be “consisting of” or “consisting of”. The numbers or ranges disclosed above may vary slightly. Whenever a numerical range is disclosed as a lower limit and an upper limit, any number falling within the range and any range falling within the range is specifically disclosed. In particular, all ranges of numerical values disclosed herein (such as “about a to about b”, “about a to b”, etc., “about ab”) It should be understood to refer to any number and range. Also, the terms set forth in the claims have their clear and general meaning unless clearly defined by the patentee. Moreover, the indefinite article “a” or “an” as used in the claims is defined herein to mean one or more of the elements incorporated into this invention. Definitions consistent with the description herein if there is any discrepancy in the use of a word or term in this specification and one or more patents or other literature words or terms incorporated herein in its entirety Should be selected.

Claims (73)

α-hydroxycarboxylic acid, α-hydroxycarboxylic acid ester, β-hydroxycarboxylic acid, β-hydroxycarboxylic acid ester, α-alkoxycarboxylic acid, α-alkoxycarboxylic acid ester, β-alkoxycarboxylic acid, β-alkoxycarboxylic acid Providing a composition comprising a reactant selected from the group consisting of an ester, a lactide, and any combination thereof; and performing the dehydroxylation reaction by contacting the composition with a dehydroxylation catalyst; Producing a product comprising an α, β-unsaturated carboxylic acid and / or its ester by
The method wherein the dehydroxylation catalyst comprises at least one selected from the group consisting of L-type zeolite, modified L-type zeolite, and any combination thereof.   The method of claim 1, further comprising conducting an esterification reaction by contacting the product with an esterification catalyst and an alcohol, thereby producing a second product comprising an α, β-unsaturated carboxylic acid ester. Method.   The process of claim 2 wherein the dehydroxylation catalyst and the esterification catalyst are the same.   The method according to claim 2 or 3, wherein the dehydroxylation reaction and the esterification reaction are performed simultaneously.   The method according to claim 2 or 3, wherein the dehydroxylation reaction and the esterification reaction are carried out in succession.   The process according to any one of claims 2 to 5, wherein the dehydroxylation reaction and the esterification reaction are carried out in a single reaction vessel.   The esterification reaction is performed in a reaction vessel comprising at least one reactor material selected from the group consisting of titanium, silanized stainless steel, quartz, and any combination thereof. 6. The method according to any one of 5 above. Alcohol, C ₁ -C ₂₀ alcohol, aryl alcohol, at least one alcohol selected from the group consisting of cyclic alcohols, and any combination thereof, according to any one of claims 2 to 7 Method.   Alcohol is methanol, ethanol, propanol, isopropanol, n-propanol, butanol, isobutanol, n-butanol, 2-ethylhexanol, isononanol, isodecyl alcohol, 3-propylheptanol, benzyl alcohol, cyclohexanol, cyclopentanol And at least one alcohol selected from the group consisting of any combination thereof.   10. A process according to any one of claims 2 to 9 wherein the esterification reaction occurs in the presence of a carrier gas containing greater than about 90% carbon dioxide.   The dehydroxylation reaction is performed in a reaction vessel comprising at least one reactor material selected from the group consisting of titanium, silanized stainless steel, quartz, and any combination thereof. The method as described in any one of -5 or 8-10.   7. The method of claim 6, wherein the single reaction vessel comprises at least one reactor material selected from the group consisting of titanium, silanized stainless steel, quartz, and any combination thereof.   13. The method according to any one of claims 1 to 12, wherein the dehydroxylation reaction occurs in the presence of a carrier gas comprising greater than about 90% carbon dioxide.   14. A process according to any one of the preceding claims, wherein the reactant is in the gas phase and the dehydroxylation catalyst is in the solid phase.   The dehydroxylation catalyst is at least one selected from the group consisting of solid oxides, zeolites other than L-type zeolites, acid catalysts, weak acid catalysts, strong acid catalysts, neutral catalysts, base catalysts, and any combination thereof. The method according to claim 1, further comprising:   The modified L-type zeolite contains at least one inorganic salt and / or oxide thereof, and the inorganic salt and / or oxide thereof is phosphate, sulfate, molybdate, tungstate, stannate, antimonic acid 16. The method according to any one of claims 1 to 15, comprising at least one selected from the group consisting of a salt and any combination thereof.   The process according to claim 16, wherein the inorganic salt and / or oxide thereof is present in the modified L-type zeolite at a concentration of about 0.1 millimoles to about 1.0 millimoles per gram of modified zeolite.   The inorganic salt comprises at least one salt selected from the group consisting of monosodium phosphate, disodium phosphate and trisodium phosphate, potassium phosphate, sodium aluminum phosphate, and any combination thereof. Item 18. The method according to Item 16 or 17.   The method according to any one of claims 1 to 18, wherein the modified L-type zeolite has undergone ion exchange at least once. The modified L-type zeolite is H ⁺ , Li ⁺ , Na ⁺ , K ⁺ , Cs ⁺ , Mg ²⁺ , Ca ²⁺ , La ²⁺ , La ³⁺ , Ce ²⁺ , Ce ³⁺ , Ce ⁴⁺ , Sm ²⁺ , Sm ³⁺ , Eu ^2+. 20. The method of any one of claims 1-19, wherein the method is associated with at least one selected from the group consisting of Eu ³⁺ , and any combination thereof.   21. A process according to any one of the preceding claims, wherein the modified L-type zeolite is a Na / KL type zeolite and the ratio of sodium ions: potassium ions is about 1:10 or greater.   The method according to any one of claims 1 to 21, wherein the conversion efficiency is about 75% or more.   23. The method according to any one of claims 1 to 22, wherein the conversion efficiency is about 90% or more.   24. A process according to any one of claims 1 to 23, wherein the product comprises about 60 mol% or more of an [alpha], [beta] -unsaturated carboxylic acid and / or ester thereof.   25. A method according to any one of claims 1 to 24, wherein the reactant is lactide.   26. The method according to any one of claims 1 to 25, wherein the reactant is derived from an organism.   The method according to any one of claims 1 to 26, wherein the dehydroxylation reaction is carried out in the presence of a polymerization inhibitor.   28. A method according to any one of claims 1 to 27, wherein the composition further comprises a solvent.   30. The method of claim 28, further comprising recycling the solvent after the dehydroxylation reaction. providing a composition comprising a reactant selected from the group consisting of α-hydroxycarboxylic acid, β-hydroxycarboxylic acid, α-alkoxycarboxylic acid, β-alkoxycarboxylic acid, and any combination thereof;
Contacting the composition with an esterification catalyst and an alcohol to effect an esterification reaction, thereby producing an intermediate comprising an ester of the reactant; and then contacting the intermediate with a dehydroxylation catalyst Carrying out a dehydroxylation reaction on to produce a product comprising an α, β-unsaturated carboxylic acid ester,
The method wherein the dehydroxylation catalyst comprises at least one selected from the group consisting of L-type zeolite, modified L-type zeolite, and any combination thereof.   The process according to claim 30, wherein the dehydroxylation reaction and / or the esterification reaction takes place in the presence of a carrier gas substantially comprising carbon dioxide.   A reactor comprising a reactor material wherein the dehydroxylation reaction and / or esterification reaction comprises at least one selected from the group consisting of titanium, silanized stainless steel, quartz, and any combination thereof 32. A method according to claim 30 or 31 performed in.   33. A process according to any one of claims 30 to 32, wherein the dehydroxylation catalyst and the esterification catalyst are the same. Alcohol, C ₁ -C ₂₀ alcohols, aryl alcohols, cyclic alcohols, and at least one selected from the group consisting of any combination thereof, The method according to any one of claims 30 to 33 .   Alcohol is methanol, ethanol, propanol, isopropanol, n-propanol, butanol, isobutanol, n-butanol, 2-ethylhexanol, isononanol, isodecyl alcohol, 3-propylheptanol, benzyl alcohol, cyclohexanol, cyclopentanol 35. The method according to any one of claims 30 to 34, wherein the method is at least one selected from the group consisting of: and any combination thereof.   The modified L-type zeolite contains at least one inorganic salt and / or oxide thereof, and the inorganic salt and / or oxide thereof is phosphate, sulfate, molybdate, tungstate, stannate, antimonic acid 36. The method according to any one of claims 30 to 35, comprising at least one selected from the group consisting of a salt, and any combination thereof.   37. The inorganic salt and / or its oxide is present in the modified L-type zeolite at a concentration of about 0.1 millimoles to about 1.0 millimoles per gram of modified zeolite. Method.   The inorganic salt comprises at least one salt selected from the group consisting of monosodium phosphate, disodium phosphate and trisodium phosphate, potassium phosphate, sodium aluminum phosphate, and any combination thereof. Item 38. The method according to any one of Items 30 to 37.   The process according to any one of claims 30 to 38, wherein the modified L-type zeolite has undergone ion exchange at least once. The modified L-type zeolite is H ⁺ , Li ⁺ , Na ⁺ , K ⁺ , Cs ⁺ , Mg ²⁺ , Ca ²⁺ , La ²⁺ , La ³⁺ , Ce ²⁺ , Ce ³⁺ , Ce ⁴⁺ , Sm ²⁺ , Sm ³⁺ , Eu ^2+. 40. The method of any one of claims 30 to 39, wherein the method is associated with at least one ion selected from the group consisting of Eu ³⁺ , and any combination thereof.   41. A process according to any one of claims 30 to 40, wherein the modified L-type zeolite is a Na / KL type zeolite and the ratio of sodium ions: potassium ions is about 1:10 or greater.   42. The method according to any one of claims 30 to 41, wherein the conversion efficiency is about 75% or more.   43. A method according to any one of claims 30 to 42, wherein the conversion efficiency is about 90% or more.   44. A process according to any one of claims 30 to 43, wherein the product comprises about 60 mol% or more of an [alpha], [beta] -unsaturated carboxylic acid ester.   45. The method according to any one of claims 30 to 44, wherein the dehydroxylation reaction is performed in the presence of a polymerization inhibitor.   46. A method according to any one of claims 30 to 45, wherein the reactant is derived from an organism.   47. The method according to any one of claims 30 to 46, wherein the composition further comprises a solvent.   48. The method of claim 47, further comprising recycling the solvent after the dehydroxylation reaction. α-hydroxycarboxylic acid, α-hydroxycarboxylic acid ester, β-hydroxycarboxylic acid, β-hydroxycarboxylic acid ester, α-alkoxycarboxylic acid, α-alkoxycarboxylic acid ester, β-alkoxycarboxylic acid, β-alkoxycarboxylic acid Providing a composition comprising a reactant selected from the group consisting of an ester, a lactide, and any combination thereof; and dehydroxylation in the presence of a carrier gas by contacting the composition with a dehydroxylation catalyst A product comprising an α, β-unsaturated carboxylic acid and / or an ester thereof,
A method wherein the carrier gas comprises greater than about 90% carbon dioxide.   50. The method of claim 49, further comprising performing an esterification reaction by contacting the composition with an esterification catalyst and an alcohol, thereby producing a second product comprising an α, β-unsaturated carboxylic acid ester. Method.   51. The method of claim 50, wherein the esterification reaction occurs in the presence of a carrier gas. A method for producing acrylic acid or acrylic ester from sugar,
(A) catalytically converting sugar to lactic acid or alkyl lactate; and (b) catalytically converting lactic acid or alkyl lactate from step (a) to acrylic acid or an acrylate ester.   53. The method of claim 52, further comprising purifying the acrylic acid or acrylate ester from step (b).   54. The method of claim 52 or 53, wherein the catalytic conversion of sugar is effected by a first chemical catalyst.   55. The method of claim 54, wherein the first chemical catalyst is a dehydroxylation catalyst.   56. The method of claim 55, wherein the dehydroxylation catalyst comprises at least one selected from the group consisting of L-type zeolite, modified L-type zeolite, and any combination thereof.   The modified L-type zeolite contains at least one inorganic salt and / or oxide thereof, and the inorganic salt and / or oxide thereof is phosphate, sulfate, molybdate, tungstate, stannate, antimonic acid 57. The method of claim 56, comprising at least one selected from the group consisting of a salt, and any combination thereof.   58. A process according to claim 56 or 57, wherein the modified L-type zeolite has undergone at least one ion exchange. The modified L-type zeolite is H ⁺ , Li ⁺ , Na ⁺ , K ⁺ , Cs ⁺ , Mg ²⁺ , Ca ²⁺ , La ²⁺ , La ³⁺ , Ce ²⁺ , Ce ³⁺ , Ce ⁴⁺ , Sm ²⁺ , Sm ³⁺ , Eu ^2+. 59. The method of any one of claims 56 to 58, wherein the method is associated with at least one ion selected from the group consisting of Eu ³⁺ , and any combination thereof.   The dehydroxylation catalyst is at least one selected from the group consisting of solid oxides, zeolites other than L-type zeolites, acid catalysts, weak acid catalysts, strong acid catalysts, neutral catalysts, base catalysts, and any combination thereof. 60. The method of any one of claims 55 to 59, further comprising:   61. The method of any one of claims 52-60, wherein the catalytic conversion of lactic acid or alkyl lactate is effected by a second chemical catalyst.   62. The method of claim 61, wherein the second chemical catalyst is an esterification catalyst. A method for producing acrylic acid or an acrylic ester from glycerol,
(A) catalytically converting glycerol to lactic acid or alkyl lactate; and (b) catalytically converting lactic acid or alkyl lactate from step (a) to acrylic acid or an acrylate ester.   64. The method of claim 63, further comprising purifying the acrylic acid / acrylic ester from step (b).   65. A process according to claim 63 or 64, wherein the catalytic conversion of glycerol is effected by a first chemical catalyst.   66. The method of claim 65, wherein the first chemical catalyst is a dehydroxylation catalyst.   68. The method of claim 66, wherein the dehydroxylation catalyst comprises at least one selected from the group consisting of L-type zeolite, modified L-type zeolite, and any combination thereof.   The modified L-type zeolite contains at least one inorganic salt and / or oxide thereof, and the inorganic salt and / or oxide thereof is phosphate, sulfate, molybdate, tungstate, stannate, antimonic acid 68. The method of claim 67, comprising at least one selected from the group consisting of a salt, and any combination thereof.   69. The method of claim 67 or 68, wherein the modified L-type zeolite has undergone at least one ion exchange. The modified L-type zeolite is H ⁺ , Li ⁺ , Na ⁺ , K ⁺ , Cs ⁺ , Mg ²⁺ , Ca ²⁺ , La ²⁺ , La ³⁺ , Ce ²⁺ , Ce ³⁺ , Ce ⁴⁺ , Sm ²⁺ , Sm ³⁺ , Eu ^2+. 70. The method of any one of claims 67 to 69, wherein the method is associated with at least one ion selected from the group consisting of Eu ³⁺ , and any combination thereof.   The dehydroxylation catalyst is at least one selected from the group consisting of solid oxides, zeolites other than L-type zeolites, acid catalysts, weak acid catalysts, strong acid catalysts, neutral catalysts, base catalysts, and any combination thereof. 71. The method according to any one of claims 66 to 70, further comprising:   72. A process according to any one of claims 63 to 71, wherein the catalytic conversion of lactic acid or alkyl lactate is effected by a second chemical catalyst.   73. The method of claim 72, wherein the chemical catalyst is an esterification catalyst.

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