KR20060077996A - Method of separating 1,3-propanediol or glycerol, or a mixture thereof from a biological mixture - Google Patents

Abstract

The present invention relates to a method for separating 1,3-propanediol, glycerol or a mixture of 1,3-propanediol and glycerol from a biological mixture, more specifically 1,3- from a biological mixture using molecular sieves. A method for separating propanediol, glycerol or a mixture of 1,3-propanediol and glycerol. This method is particularly useful in terms of product recovery and energy consumption, and in particular, it is possible to eliminate feedback inhibition by increasing the concentration of 1,3-propanediol and increase the total production rate of 1,3-propanediol High capital productivity and high reaction yield can be achieved.

1,3-propanediol, glycerol, molecular sieve, zeolite

Description

Method for Separating 1,3-propanediol or Glycerol, or a Mixture Thereof from a Biological Mixture             

1 illustrates adsorption of 1,3-propanediol from cell-free fermentation broth and desorption using an ethanol / water aqueous solution on a zeolite-filled column.

2 shows the elution of 1,3-propanediol from the larger scale zeolite column.

The present invention relates to a process for separating 1,3-propanediol, glycerol or a mixture of 1,3-propanediol and glycerol from a biological mixture.

1,3-propanediol is a monomer of potential utility in the production of polyester fibers and in the production of polyurethanes and cyclic compounds.

Methods for preparing 1,3-propanediol can be broadly classified into chemical and biological methods. Typical chemical production methods include, for example, ethylene oxide reduced after catalytic liquid phase hydration of acrolein with a catalyst in the presence of phosphine, water, carbon monoxide, hydrogen and acid, or hydrocarbons such as glycerol, It can be converted to 1,3-propanediol by reaction in the presence of a catalyst, carbon monoxide and hydrogen. Although 1,3-propanediol can be produced by this method, this method generates a waste stream containing expensive and environmental pollutants.

It is known to ferment glycerol by microorganisms to biologically produce 1,3-propanediol. 1,3 bacterial strain capable of producing a gloss-propanediol is a tree Stadium (Clostridium), Enterobacter bakteo (Enterobacter), one Rio bakteo (Illyobacter), keurep when Ella (Klesiella), Lactobacillus bacteria (Lactobacillus), Tupelo bakteo ( Pelobacter ), Citrobacter group. Glycerol is converted to 1,3-propanediol through a two-step enzymatic catalysis, which no longer metabolizes, resulting in high concentration in the medium.

Both methods of synthesizing 1,3-propanediol involve impurity that must be removed prior to polymerization. In the case of the acrolein pathway, such impurities include water, acrolein, and other organic compounds, and biological pathways from glucose can include impurities such as water, glucose, organic acids, salts, glycerol and other compounds. Due to the high boiling point and hydrophilicity of 1,3-propanediol, it is difficult to separate 1,3-propanediol from the impurities and reaction byproducts and / or reaction coproducts by standard methods.                         

Known methods of purifying 1,3-propanediol have serious problems. Aqueous 1,3-propanediol liquid-liquid extraction (Malinowski, Biotech. Prog. 13 (2), 127-30 (1999)) has been described as "not good enough to effect simple extraction". Other liquid-liquid extractions (DE 86-3632397) use cyclohexane to extract dimeric acrolein from 1,3-propanediol, but this method takes more than an hour and is very useful for removing impurities other than acrolein. Not. HPLC separation of 1,3-propanediol using ion-exclusion or reversed-phase methods (Mao, J. Liq. Chromatogr. 17 (8), 1811-9 (1994)) is well known, but the cost of chromatography media and high pressure processes Therefore it can only be used on a small scale. One standard technique for purifying 1,3-propanediol is distillation followed by evaporation, both of which require large amounts of heat injection and can be expensive.

In addition, there is a feedback suppression problem in the method of preparing 1,3-propanediol, i.e., in the case of biological pathways, the production of high concentrations of 1,3-propanediol further reduces the 1,3-propanediol production or cell growth rate. It is well known that it can. (Cameron et al., Biotech. Prog. 14, 116-25 (1998)). Thus, separation methods usable in the same reactor during 1,3-propanediol preparation will be of additional value.

Optional adsorbents, such as carbon and zeolites, have also been proposed for 1,3-propanediol separation. Zeolites can generally be described as aluminosilicates, which are complexes characterized by a three-dimensional framework structure surrounding a cavity filled with ionic and water molecules. In the case of commercially useful zeolites, water molecules can be removed from or substituted in the skeleton without destroying the structure. Formula _{M 2 / n O · Al 2} O 3 · xSiO 2 · yH 2 O (M is n is the cation; x is at least 2;. Y is a number which is determined according to the degree of porosity and hydration of the zeolite, generally from 0 to 8) It can be represented as. In the case of naturally occurring zeolites, M is generally represented by the ratios Na, Ca, K, Mg and Ba, which generally reflect approximate geochemical abundances. The cation M is loosely bound to the structure and can be fully or partially substituted with other cations by conventional ion exchange. The zeolite structure consists of a corner-connected tetrahedron with Al or Si atoms in the center of the tetrahedron and oxygen atoms at the corners. Such tetrahedra are combined with well defined repeating structures comprising various combinations of 4-, 6-, 8-, 10- and 12-membered rings.

Molecular sieves, a subgroup of zeolites, have recently been considered for 1,3-propanediol purification. Since the zeolites used for 1,3-propanediol tablets are not in proton form, they tend to contaminate the mixture or adsorbate through leaching of cations. Guenzel et al. (Chem.-Ing.-Tech. 62 (9), 748-50 (1990)) tested dealuminated NaY and silicalite for separation of 1,3-propanediol / aqueous solution. A maximum load of 0.12 g of 1,3-propanediol / 1 g of zeolite was obtained. However, they did not investigate glycerol selectivity. Schlieker et al. (Chem.-Ing.-Tech. 64 (8), 727-8 (1992)) used activated carbon, but experienced a fairly nonspecific adsorption of glycerol, an expensive intermediate, only 2.5. A 1,3-propanediol fermentation productivity of g / L hr was achieved. Schellner et al. (J. Prakt. Chem. 336 (5), 404-7 (1994)) tested two X, two Y and Na-ZSM-5 zeolites. Although it has been found that Na-ZSM-5 is superior to X and Y zeolites, salts can be leached back into the mixture or adsorbate stream. Recovery of 1,3-propanediol from zeolites has not been discussed.

Improvements in the process for purifying 1,3-propanediol, glycerol, or mixtures of 1,3-propanediol and glycerol from fermentation broths are particularly necessary in terms of product recovery, energy consumption and feedback inhibition.

The present invention relates to a method for efficiently separating 1,3-propanediol, glycerol, or a mixture of 1,3-propanediol and glycerol from a biological mixture using molecular sieves. After adhering the mixture components to molecular sieves such as zeolites, each component is separated with high efficiency through an appropriate elution solution.

The present invention provides a novel technique for separating 1,3-propanediol, glycerol, or a mixture of 1,3-propanediol and glycerol from a biological mixture using molecular sieves. The method of the present invention uses a relatively simple device and is easy to maintain compared to other available methods. It also solves the major problems of high cost and product variability of currently available adsorbents.

The cell-free reaction solution according to the present invention is sufficient to remove impurities associated with the reaction solution and to concentrate 1,3-propanediol at a temperature and flow rate suitable for adsorption with a zeolite-adsorbent selected from the group of molecular sieves. By contacting for a time, the concentrated product is optionally provided. If a product in which 1,3-propanediol is concentrated is desired, the present invention also includes a method of desorbing adsorbed 1,3-propanediol to thereby provide a concentrated product.

The method, based on adsorption / desorption, is particularly useful for high recovery of products with lower distillation costs by recovering the product in ethanol instead of water.

One group of zeolite species used in the process of the invention is (Na, TPA) n [Al _n Si ₉₆ -n O ₁₉₂ ]-16 H ₂ 0 for ZSM-5 and (Na, _{TBA) n [Al n Si 96} -nO 192] ~ 16 H 2 0 - an intermediate of the synthesis in such a way that it can be described by the formula - a pore synthetic zeolite. The structure and synthesis of such synthetic zeolites are well known in the art. Such zeolites can then be converted to the hydrogen form by standard procedures well known in the art (Donald W. Breck; Zeolite Molecular Sieves; supra). When the equilibrium cation in the zeolite is H +, the backbone is a solid acid that can have form-selective catalytic or adsorptive properties due to the closure of acidic protons in the zeolite pore structure. The average pore size of H-ZSM-5 is 5.5 mm 3.

The present invention uses H-ZSM-5 to separate 1,3-propanediol from the reaction solution. Ethanol / water is also used to desorb 1,3-propanediol from ZSM-5 zeolite. Adsorbed 1,3-propanediol was replaced by ethanol / water mixture. In addition, the yield of 1,3-propanediol was increased by increasing the concentration of ethanol, indicating that elution with an ethanol-rich mixture of 1,3-propanediol is preferred. The total recovery of the 1,3-propanediol product was calculated to be as high as 96.1%. Although the present invention uses ethanol to elute the adsorbed 1,3-propanediol, any C ₁ -C ₄ alcohol can be used. 1,3-propanediol desorption is preferably a temperature of between 80 ℃ at room temperature.

In one other embodiment, two stage programmed desorption is accomplished by injecting increasing concentrations of ethanol into the column. The first low concentration eluted unwanted compounds, while the second high concentration eluted mainly 1,3-propanediol. This method reduced the level of contamination by other components of 1,3-propanediol.

In another embodiment, 1,3-propanediol and glycerol are simultaneously removed from fermentation broth by using H-ZSM-5 zeolite (Si / Al = 500) or H-ZSM-5 zeolite (Si / Al = 15) together. Each has a high total load and the 1,3-propanediol: glycerol selectivity is about the same. The resulting 1,3-propanediol / glycerol mixture is then separated using a gradient eluent as described above. The mixture may be further purified using conventional separation methods such as distillation.

In another embodiment, the 1,3-propanediol is removed from the fermentation broth using a molecular sieve having a high selectivity to 1,3-propanediol / glycerol as described above, and then the fermentation broth is subjected to the high load molecule of glycerol. Sequential treatment with sieves (eg H-ZSM-5 zeolite, Si / Al = 15) removes useful glycerol components.

Combinations of the above methods for recovering 1,3-propanediol, glycerol or a mixture of 1,3-propanediol and glycerol continuously or in parallel are within the scope of the present invention.

It has been found that using any of the molecular sieves mentioned above in the separation step and using ethanol in the elution step achieves yields in excess of 90%. H-ZSM-5 (specific form of MFI) is selected as such purification means, but various forms of zeolites can be used. Other zeolites for the purposes of the present invention can be selected from the group consisting of MFI, MEL, BEA, MOR, FAU, LTL, GME, FER, MAZ, OFF, AFI, AEL and AET and materials having the same form as those particular zeolites. Can be. Preferred structures include FAU, MFI, MEL and BEA. Such molecular sieves are well known in the art and are described by Atlas of Zeolite Structure Types. Examples of such molecular sieves include, but are not limited to, those of high Si / Al ratios (eg, 5 or more) that exhibit the acidity, hydrophobicity, pore size, and other properties of a particular zeolite backbone. Selectivity can be further improved by physical treatments such as drying and / or chemical treatments such as coating and altering molecular sieves.

In summary, the present invention selectively separates 1,3-propanediol, glycerol, or a mixture of 1,3-propanediol and glycerol from a mixture of contaminants, by-products, and co-product compounds using specific molecular sieves. . The present invention also concentrates it using specific desorbents during separation. The present invention also minimizes the subsequent distillation or purification costs.

Identification and concentration measurement of 1,3-propanediol and glycerol separated in the present invention was analyzed using gas chromatography, the analysis conditions are shown in the table below.

* Gas chromatography analysis condition

The invention is further defined in the following examples.

Example 1

Selective concentration of 1,3-propanediol via adsorption / desorption column                     

A 23 g extrudate (0.32 cm in diameter) of H-ZSM-5 (~ 75% H ⁺ , 25% Na ⁺ cation balance, Si: Al = 25, 70% zeolite, 30% aluminum binder) was added to Amicon. Fill into a column (40 ml column volume, ˜1 ”ID) and pump the reaction solution (47 g / L 1,3-propanediol) at 0.8 ml / min through the column. The 1,3-propane diol column This flow was continued until exiting was observed At t = 120 minutes, 50:50 (v: v) ethanol: H ₂ 0 was pumped through the column to 0.8 ml / min to adsorb 1,3 The propanediol product was eluted The mass of adsorbed 1,3-propanediol was 2.10 g, the mass of desorbed 1,3-propanediol was 2.02 g, and the calculated recovery of the product was 96.1%.

Example 2

Programmed Solvent Desorption of Adsorbed 1,3-propanediol

A column (1 L volume, 1.875 "ID) filled with H-ZSM-5 zeolite (see Example 1) was first subjected to 1,3-propanediol, glycerol, glucose and other ingredients (feed concentration: 8.0 g / L 1,3 Contact with a mixture of propanediol / 29.7 g / L glycerol) by injecting 5% EtOH / 95% H ₂ 0 and 50% EtOH / 50% H ₂ 0 in this column (10 ml / min) in order. Step programmed desorption was attempted: 5% EtOH / 95% H ₂ 0 eluted the undesirable glycerol, while 50% EtOH / 50% H ₂ 0 eluted mainly 1,3-propanediol. The 5% EtOH / 95% H ₂ 0 step (t <23 min) yielded a fraction consisting of 5.8 g of glycerol and 1.8 g of 1,3-propanediol (mass ratio glycerol: 1,3-propanediol = 3.17) The 50% EtOH / 50% H ₂ 0 step (t> 23 min) yielded a fraction consisting of 9.29 g of glycerol and 13.5 g of 1,3-propanediol (mass ratio 1,3-propanediol: glycerol = 1.46). Therefore, 50% EtOH / 50% H The 20 step significantly increased the ratio of 1,3-propanediol: glycerol compared to the feed (mass ratio 1,3-propanediol: glycerol = 0.27), and the 1 of 50% EtOH: 50% H ₂ 0. The, 3-propanediol elution required less heat injection due to lower latent heat of ethanol compared to water, therefore, the programmed elution performed in two steps in this example is a glycerol rich fraction and 1,3-propanediol Abundant fractions resulted, otherwise they would elute together (FIG. 2).

Improvements in the process for purifying 1,3-propanediol, glycerol or a mixture of 1,3-propanediol and glycerol from the reaction solution are particularly necessary in terms of product recovery, energy consumption and feedback suppression. Techniques for selectively removing 1,3-propanediol during fermentation reactions would be very useful. This technique is expected to eliminate feedback inhibition and increase the total production rate of 1,3-propanediol by reducing the available 1,3-propanediol concentration. As a result, higher capital productivity and potentially higher reaction yields will be achieved.

Claims (2)

 (1) Biological mixtures containing 1,3-propanediol, glycerol or a mixture of 1,3-propanediol and glycerol may be prepared by MFI, MEL, BEA, MOR, FAU, LTL, GME, FER, MAZ, OFF, AFI. Contacting with a sufficient amount of one or more zeolites selected from the group consisting of AEL and AET and materials of the same type as such zeolites, (2) contacting the zeolite of step (1) with a desorbent selected from the group consisting of ethanol: aqueous solution or any C ₁ -C ₄ alcohol: aqueous solution, (3) collecting 1,3-propanediol, glycerol, or a mixture of 1,3-propane diol and glycerol eluted from the molecular sieve in step (2), and (4) A process for separating 1,3-propanediol, glycerol or a mixture of 1,3-propanediol and glycerol, optionally comprising repeating one or more times from steps (1) to (3). The process according to claim 1, wherein the first zeolite is selected in step (1) to selectively adsorb a mixture of 1,3-propanediol and glycerol from the biological mixture, and a series of steps (2), (3) and optionally (4). After doing (5) selectively adsorbing 1,3-propanediol or glycerol from the mixture of 1,3-propanediol and glycerol by contacting the mixture of 1,3-propanediol and glycerol with a second zeolite, (6) contacting the zeolite of step (5) with a desorbent such as ethanol: aqueous solution or any C ₁ -C ₄ alcohol: aqueous solution, (7) collecting 1,3-propanediol or glycerol eluted from zeolite in step (6), (8) optionally repeating one or more times from a series of steps (5) to (7) to obtain purified 1,3-propanediol or glycerol.

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