DE19726151B4 - Use of monolithic sorbents for simulated moving bed separation processes - Google Patents

Abstract

Process for the separation of at least two substances according to the "simulated moving bed" process using monolithic sorbents, characterized in that
a) monolithic sorbents derivatized with separation effectors in the form of porous shaped bodies of SiO ₂ are used, which have interconnected macropores and mesopores in the walls of the macropores, the diameter of the macropores having a median greater than 0.1 μm and the diameter of the mesopores has a median value between 2 and 100 nm,
and where
b) the entire column bed is subdivided into individual columns arranged cyclically one behind the other, so that the total number of columns is a multiple of 4, and between the individual columns there are 4 two-way valves which connect to the 4 supply and discharge lines,
and that for separation
c) through repeated switching of the valves after a defined time by one column unit in the direction of the fluid movement each column of columns successively passes through all four zones until the supply and outlet lines ...

Description

The Invention relates to the use of monolithic sorbents, especially those containing separation effectors for preparative Separations, in particular for "Simulated Moving Bed "separation process.

For the economy from preparative Separations are the achievement of high flow rates, short elution times and compliance with moderate operating pressures are key factors. at preparative Separation of matter has gained importance in countercurrent processes. Since it is technically very difficult, an actual Movement of a stationary Phase, the movement of the stationary phase is simulated. This is the entire column bed divided into cyclically connected individual columns. The total number the columns is typically a multiple of four, since such a system has four chromatographic zones. After a defined time the lines are switched, causing a movement of the column bed is simulated in the opposite direction. For the continuous Procedure of "simulated moving bed "chromatography (SMB chromatography) are usually particulate as separating materials Used sorbents. The column packs used do not leave any optimal flow rates, because the operating pressure is very high for particulate carriers. Also is the mechanical stability the particular Sorbs beds are not very good. Furthermore, it is necessary for SMB chromatography a series of chromatographic columns (typically up to 24) with as possible to provide the same properties. This is with particulate sorbent beds only with big Effort when packing the columns and feasible in the selection of packed columns.

Out US 4,426,232 A For example, a method of separating at least two substances is known, which is carried out according to the simulated moving bed method and in which the substance separation takes place using monolithic carbon sorbents. The sorbents used consist of shaped particle aggregates which have repeating monomer units which are composed at least of carbon and hydrogen. The shaped particle aggregates are prepared by treating an inorganic shaped support with a precursor for a so-called "pyropolymer" and then treating at elevated temperature in the range of 400 to 1200 ° C. In this way, at least one monolayer of a carbon-containing pyrolyzed polymer having repeating units of carbon and hydrogen is formed on the inorganic shaped support. In EP 0 103 406 A2 For example, these sorbents are used to selectively separate sucrose from aqueous solutions containing betaines, salts and molasses.

task The invention is chromatographic preparative separation processes, in particular for the SMB procedures to provide high flow rates at moderate operating pressure exhibit.

It It was found that monolithic sorbents for high resolution flow rates can be used; thus, a higher Throughput per unit time can be achieved.

object The invention relates to processes for preparative chromatographic Separation of at least two substances, in particular according to the SMB method, being considered stationary Phase a monolithic sorbent is used.

• a) mit Separationseffektoren derivatisierte monolithischen Sorbentien in Form von porösen Formkörpern aus SiO₂ verwendet werden, welche untereinander verbundene Makroporen sowie Mesoporen in den Wänden der Makroporen aufweisen, wobei der Durchmesser der Makroporen einen Medianwert größer als 0,1 μm aufweist und der Durchmesser der Mesoporen einen Medianwert zwischen 2 und 100 nm aufweist, und wobei
• b) das gesamte Säulenbett in zyklisch hintereinandergeschaltete Einzelsäulen unterteilt ist, sodass die Gesamtzahl der Säulen ein Vielfaches von 4 ist, und sich zwischen den Einzelsäulen je 4 Zweiwegeventile befinden, die eine Verbindung zu den je 4 Zufuhr- und Auslassleitungen darstellen, und dass zur Trennung
• c) durch wiederholtes Weiterschalten der Ventile nach einer definierten Zeit um eine Säuleneinheit in Richtung der Fließmittelbewegung jede Einzelsäule nacheinander alle vier Zonen durchläuft, bis die Zufuhrund Auslassleitungen wieder ihre ursprüngliche Position einnehmen, sodass sich bei geeigneter Wahl der Fließgeschwindigkeit und Taktzeit der Ventilschaltungen nach mehreren Zyklen ein stationärer Zustand einstellt und dass
• d) die getrennten Produkte in reiner Form als Extrakt- und Raffinatströme abgenommen werden können.

In particular, the object of the present invention is achieved by a new method for separating at least two substances according to the simulated moving bed method using monolithic sorbents, which is characterized in that

• a) monolithic sorbents derivatized with separation effectors in the form of porous shaped bodies of SiO ₂ are used, which have interconnected macropores and mesopores in the walls of the macropores, the diameter of the macropores having a median greater than 0.1 μm and the diameter of the mesopores has a median value between 2 and 100 nm, and wherein
• b) the entire column bed is subdivided into cyclically single columns, so that the total number of columns is a multiple of 4, and between the individual columns are 4 two-way valves that connect to each 4 supply and discharge lines, and that for separation
• c) by repeatedly switching the valves after a defined time by one column unit in the direction of the fluid movement, each individual column successively passes through all four zones until the supply and discharge lines return to their original position, so that with a suitable choice of the flow rate and cycle time of the valve circuits after several cycles sets a steady state and that
• d) the separated products can be removed in pure form as extract and Raffinatströme.

to execution the process becomes the flow rate in a column from 25 mm diameter to a value higher than 40 ml / min.

1 shows a schematic representation of the method of countercurrent chromatography, which is the basis of the simulated moving bed (SMB) chromatography.

2 shows a preparative separation of a test mixture of toluene, 2-nitroacetanilide and 3-nitroacetanilide at different mobile phase flow rates ( 2a : 40 ml / min; 2 B : 130 ml / min; 2c : 200 ml / min). Experimental details are described in Example 1.

3 shows the separation of dimethyl phthalate / dibutyl phthalate on a C ₁₈ RP phase. Experimental details are described in Example 2.

Monolithic sorbents are known in principle from the literature; These include, in particular, porous ceramic shaped bodies, as they are in WO 94/19 687 and in WO 95/03 256 are disclosed. The term monolithic sorbents broadly encompasses molded articles made of polymers, as described by F. Svec and JM Frechet (1992) Anal. Chem. 64, pp. 820-822, and by S. Hjerten et al. (1989) J. Chromatogr. 473, pages 273-275. Particular preference is given to monolithic sorbents based on porous shaped bodies which have interconnected macropores and mesopores in the walls of the macropores, the diameter of the macropores having a median value greater than 0.1 μm, and the diameter of the mesopores having a median value of 2 and 100 nm.

Monolithic sorbents thus consist of materials, as they are for particulate sorbents in use. In many cases (eg, SiO ₂ ), these sorbents can be readily used for chromatographic separations. More often, however, the base supports are derivatized to improve release properties; In doing so, additional groupings are introduced, which are grouped under the name of separation effectors.

• a) Die Derivatisierung mit Silanderivaten der Formel I SiX_nR¹ _(3-n)R² I worin X Methoxy, Ethoxy oder Halogen, R¹ C₁-C₅-Alkyl, n 1, 2 oder 3 bedeuten und R² eine der im folgenden angegebene Bedeutungen besitzt: a1) unsubstituiertes oder substituiertes Alkyl oder Aryl, wie z. B. n-Octadecyl, n-Octyl, Benzyl- oder Cyanopropyl; a2) anionische oder saure Reste, wie z. B. Carboxypropyl; a3) kationische oder basische Reste, wie z. B. Aminopropyl, Diethylaminopropyl oder Triethylammoniumpropyl; a4) hydrophile Reste, wie z. B. (2,3-Dihydroxypropyl)-oxypropyl; a5) bindungsfähige aktivierte Reste, wie z. B. (2,3-Epoxypropyl)-oxypropyl.
• b) Die Adsorption oder chemische Bindung von Polymeren wie Polybutadien, Siloxanen, Polymeren auf der Grundlage von Styrol/Divinylbenzol, von (Meth)acrylsäurederivaten oder von anderen Vinylverbindungen, sowie von Peptiden, Proteinen, Polysacchariden und Polysaccharidderivaten an dem Basisträger;
• c) Die chemische Bindung von unter b) genannten Polymeren über die unter a) genannten Derivate; dazu gehören Pfropfpolymerisate von Poly(meth)acrylsäurederivaten auf diolmodifiziertem Kieselgel nach EP-B-0 337 144 .
• d) Die Adsorption oder chemische Bindung von chiralen Phasen, wie z. B. von Aminosäurederivaten, Peptiden oder Proteinen, oder von Cyclodextrinen, Polysacchariden oder Polysaccharidderivaten.

Separation effectors and methods for their introduction into the base carrier are known in principle to the person skilled in the art. Examples of reactions with which separation effectors can be introduced are:

• a) The derivatization with silane derivatives of the formula I. SiX _n R ¹ _(3-n) R ² I wherein X is methoxy, ethoxy or halogen, R ^{1 is} C ₁ -C ₅ -alkyl, n is 1, 2 or 3 and R ^{2 has} one of the meanings given below: a1) unsubstituted or substituted alkyl or aryl, such as. N-octadecyl, n-octyl, benzyl or cyanopropyl; a2) anionic or acidic radicals, such as. For example, carboxypropyl; a3) cationic or basic radicals, such as. Aminopropyl, diethylaminopropyl or triethylammoniumpropyl; a4) hydrophilic radicals, such as. B. (2,3-dihydroxypropyl) -oxypropyl; a5) bondable activated radicals, such as. B. (2,3-epoxypropyl) -oxypropyl.
• b) the adsorption or chemical bonding of polymers such as polybutadiene, siloxanes, polymers based on styrene / divinylbenzene, of (meth) acrylic acid derivatives or of other vinyl compounds, and of peptides, proteins, polysaccharides and polysaccharide derivatives on the base support;
• c) The chemical bonding of polymers mentioned under b) via the derivatives mentioned under a); These include graft polymers of poly (meth) acrylic acid derivatives on diol-modified silica gel EP-B-0 337 144 ,
• d) The adsorption or chemical bonding of chiral phases, such as. As of amino acid derivatives, peptides or proteins, or of cyclodextrins, polysaccharides or polysaccharide derivatives.

Further common derivatization and derivatization methods are known in the art and in common manuals such as Unger, K.K. (ed) Porous Silica, Elsevier Scientific Publishing Company (1979) or Unger, K.K. Packings and Stationary Phases in Chromatographic Techniques, Marcel Dekker (1990).

• a) Aus DE 38 11 042 sind unter anderem Monomere bekannt, die zur Herstellung von Ionenaustauschern geeignet sind; dazu gehören beispielsweise Acrylsäure, N-(Sulfoethyl)-acrylamid, 2-Acrylamido-2-methylpropansulfonsäure, N,N-Dimethylaminoethyl-acrylamid, N,N-Diethylaminoethyl-acrylamid, sowie Trimethylammoniumethyl-acrylamid.

Further examples of different separation effectors and of methods for introducing separation effectors into monolithic sorbents are mentioned in the following publications:

• a) Off DE 38 11 042 Among others, monomers are known which are suitable for the production of ion exchangers; these include, for example, acrylic acid, N- (sulfoethyl) -acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, N, N-dimethylaminoethyl-acrylamide, N, N-diethylaminoethyl-acrylamide, and trimethylammoniumethyl-acrylamide.

• b) Aus DE 43 10 964 sind Monomere bekannt, die einen Oxiranring, einen Azlactonring oder eine Gruppierung enthalten, die in einen Azlactonring umgesetzt werden kann. Polymere, die derartige Monomere enthalten, sind besonders gut für die Bindung von Affinitätsliganden oder von Enzymen geeignet. Affinitätsliganden sind beispielhaft in DE 43 10 964 offenbart.

Other monomers mentioned in this document allow the binding of affinity ligands or of enzymes, or are suitable for reversed phase chromatography: these include, for example, acrylic acid, acrylamide, allylamine or acrylonitrile.

• b) Off DE 43 10 964 For example, monomers are known which contain an oxirane ring, an azlactone ring, or a moiety that can be converted to an azlactone ring. Polymers containing such monomers are particularly well suited for the binding of affinity ligands or enzymes. Affinity ligands are exemplary in DE 43 10 964 disclosed.

Farther can the epoxide groups in such polymers in an advantageous manner be further reacted, whereby ion exchangers, thiophilic sorbents or sorbents for provided the metal chelate or hydrophobic chromatography become. For example, phosphoric acid, diethylamine, trimethylamine, sulphurous acid or complexing agents such as iminodiacetic acid added to the oxirane ring.

The production of thiophilic sorbents and sorbents for metal chelate chromatography is described in DE 43 10 964 disclosed.

In DE 43 33 674 and in DE 43 33 821 Such reactions, with the aid of which ion exchangers can be provided, are disclosed.

In DE 43 23 913 describe sorbents for hydrophobic interaction chromatography.

chiral Separating materials for the separation of enantiomers are in the art in large numbers known. These are only particulate separation materials. The known chiral separation materials consist of either chiral compound itself (for example cellulose triacetate) or but a chiral separation effector is mounted on a support or chemically to a carrier bound. Furthermore Is it possible, chiral separation effectors with a stationary phase to interact, to add in the eluent (dynamic Occupancy).

• a) Aminosäuren und ihre Derivate, z. B. L-Phenylalanin, oder D-Phenylalanin, Ester oder Amide von Aminosäuren oder acylierte Aminosäuren oder Oligopeptide;
• b) natürliche und synthetische Polymere mit einer Asymmetrie oder Dissymmetrie in der Hauptkette; dazu gehören Proteine (z. B. saures α₁-Glycoprotein, Rinderserumalbumin, Cellulase; siehe J. Chrom. 264, Seiten 63–68 (1983), J. Chrom. 269, Seiten 71–80 (1983), WO 91/12 221 ), Cellulose und Cellulosederivate, sowie andere Polysaccharide und deren Derivate (z. B. Cellulosetribenzoat, Cellulosetribenzylether, Cellulose-trisphenylcarbamat, Cellulose-tris-3-chlorobenzoat, Amylosetris-(3,5-dimethylphenylcarbamat), Cellulose-tris-(3,5-dimethylbenzoat), Cellulose-tris-(3,5-dimethylphenylcarbamat); siehe EP 0 147 804 , EP 0 155 637 , EP 0 718 625 );
• c) Cyclodextrine und seine Derivate (z. B. J. High Resol. Chrom. & Chromat. Comm. 3, Seiten 147–148 (1984); EP 0 407 412 ; EP 0445604 );
• d) Polymere mit Asymmetriezentren in der Seitenkette (z. B. EP 0 249 078 ; EP 0 282 770 ; EP 0 448 823 ).

Chiral separation effectors are known in large numbers; the most important groups of known chiral separation effectors are:

• a) amino acids and their derivatives, eg. L-phenylalanine, or D-phenylalanine, esters or amides of amino acids or acylated amino acids or oligopeptides;
• b) natural and synthetic polymers with asymmetry or dissymmetry in the main chain; these include proteins (eg, acid α ₁ -glycoprotein, bovine serum albumin, cellulase, see J. Chrom., 264, pp. 63-68 (1983), J. Chrom., 269, pp. 71-80 (1983), WO 91/12221 ), Cellulose and cellulose derivatives, as well as other polysaccharides and their derivatives (for example cellulose tribenzoate, cellulose tribenzyl ether, cellulose tris-phenylcarbamate, cellulose tris-3-chlorobenzoate, amylosetris (3,5-dimethylphenylcarbamate), cellulose tris- (3, 5-dimethylbenzoate), cellulose tris- (3,5-dimethylphenylcarbamate); EP 0 147 804 . EP 0 155 637 . EP 0 718 625 );
• c) cyclodextrins and its derivatives (e.g., J. Biol. Resol., Chrom. & Chrom., Comm., 3, pp. 147-148 (1984); EP 0 407 412 ; EP 0445604 );
• d) polymers with asymmetric centers in the side chain (eg. EP 0 249 078 ; EP 0 282 770 ; EP 0 448 823 ).

details the production of the various sorbents and their use can taken from the above publications; the relevant disclosure This document is by reference in the present application introduced.

The monolithic sorbents mentioned above may be included in material separation devices which can be handled essentially like chromatographic columns.

In 1 the process of countercurrent chromatography, which is the basis of simulated moving bed (SMB) chromatography, is shown schematically. Therein (1) signifies the stream of the sorbent. In the SMB process, the physically difficult to be realized current of the sorbent is simulated by cyclic switching of multi-way valves, which connect several connected to a cycle columns.

The Experimental realization of the separation was carried out on an SMB plant, the as explained below Four-zone model is working. Also according to the invention SMB systems used in other models, eg. B. the Three-zone model work. Suitable process variants are those skilled in the art from the Literature known.

By the countercurrent principle is the SMB for the separation of binary mixtures (eg, the two enantiomers of a racemate) in an ideal manner suitable. But also for Other chromatographic separation methods are known SMB methods. Thus, in J. Chromatogr. 719, pages 267-274 (1996) the application of a SMB method described on the purification of monoclonal antibodies. Also for the separation of multicomponent mixtures can be used with SMB processes. Such a separation is for example in Biosci. Biotech. Biochem. 56, pages 801-802 (1992). Process parameters for other separations may be the Determine professional by optimization.

Separations according to the SMB method are explained below by way of example for separations of two substances:
The continuous mode of operation of the SMB process, as shown schematically by way of example in FIG. 1, permits the setting of a steady-state state in the continuous eluent ( 3 ), as well as a solution of the binary mixture to be separated (Feed; 4 )) fed to the system and also continuously the two separate components (raffinate ( 6 ) and extract ( 5 )) can be led out of the system. The feeding in and out of said streams is carried out by means of 4 pumps (not shown). The main stream of the eluent ( 2 ) is recirculated with another pump (recycling pump, not shown). Since therefore only a smaller amount of fresh eluent must be supplied to the system (feed + eluent _(new) = raffinate + extract), the solvent consumption per unit of product in the SMB is significantly lower than in the case of batch chromatography. The column bed of a stationary phase is divided into 4 zones (one adsorption and desorption zone for the two components to be separated), which are defined relative to the feed and outlet points in the SMB:
Zone I - between eluent and extract line
Zone II - between extract and feed line
Zone III - between feed and raffinate pipe
Zone IV - between raffinate and eluent pipe

in the Case of the separation of binary mixtures can now conditions, d. H. flow rates in zones I-IV, in which the weaker ones retarded Component with the mobile phase and the more retained component with the stationary Phase moves. The separated components can then be in pure form with the extract-wise raffinate stream.

It is technically very difficult, an actual Movement of a stationary Phase (1) to realize. Therefore, this movement becomes the stationary phase simulated. For this purpose, the entire column bed is connected in cyclic succession Single column divided. The total number of columns is a multiple of the number 4, since the system, as mentioned above, 4 chromatographic Owns zones. Between the individual columns there are 4 two-way valves each, which represent a connection to the 4 supply and discharge lines. by virtue of these valves, so every point between the columns can be any Function (eluent, feed or raffinate or extract outlet). At a given time, the location defines the 4 supply and discharge lines the 4 chromatographic zones. Now the position of the 4 lines after a defined time around a column unit in the direction of Superplasticizer movement switched on, this corresponds to a movement of the column bed in the opposite direction. By switching the feed points at defined intervals goes through so every single column successively all 4 zones, until the supply and outlet lines again their original one Take position and thus a cycle is completed.

After this several cycles were completed, it turns a stationary state It is a suitable choice of flow rates in the system and appropriate cycle time for allows the valve circuits remove the separated products in pure form as extract and raffinate streams.

It was found that at Using these preferred sorbents, the flow rate over a wide range can be varied without the release properties be worsened. Taking advantage of this property is it possible, the river speed to adapt to the elution profile without reducing the separation efficiency becomes. As a result, the time required for separation can be greatly reduced. Especially for preparative Separations thus result in great advantages. For the application The SMB method is also the low pressure drop at high flow rate relevant, since in this method a number of columns connected in series become.

The usual flow rate a pillar the dimension 25 mm in diameter, with particulate particles is packed 40 ml / min. As Example 1 shows in detail, let the non-particulate carrier I a much higher Operating speed too. This makes the separation task much more economical solved become.

By Injection of increasing concentrations of components (e.g. 100, 300, 600 μl per component) and evaluation by ECP method (Flution by characteristic points) as in Guiochon, Shirazi, Katti, Fundamentals of Preparative and Nonlinear Chromatography, Academic Press, Boston, 1994, page 83 f described, can the adsorption isotherms of the components are determined.

For example (see Example 2), the following modified Langmuir isotherms were found for components A (dimethyl phthalate) and B (dibutyl phthalate):

From the determined isotherms can be prepared according to the in RM Nicoud, F. Charton, J. Chromatogr. 702 (1995) 97 et seq., For example with the help of the simulation software HELP, the separation conditions for a suitable SMB system are determined: Column dimension [mm] 93 × 25 Number of columns 8th Flow rate feed [ml / min] 1.9 Feed concentration [g / l] 320 + 320 Flow rate recycling [ml / min] 44.1 Flow rate of raffinate [ml / min] 2.9 Flow rate of extract [ml / min] 21.8 Cycle switching time [min] 2.24 Concentration of raffinate [g / l] 209.7 Concentration extract [g / l] 27.89 Purity raffinate / extract > 99.9

Examples:

The the following examples illustrate the invention; they mean no restriction of the inventive concept.

Example 1: Separation of toluene, 2-nitroacetanilide and 3-nitroacetanilide at different flow rates

A sample containing toluene, 2-nitroacetanilide and 3-nitroacetanilide is separated at different mobile phase flow rates: Conditions: sorbent: monolithic sorbent (SiO ₂ ; 93 x 25 mm) mobile phase: n-heptane / dioxane (90/10; v / v) Sample volume: 40 μl detection: UV 254 nm Flow rate: 40, 130, 200 ml / min Fig. 2a Fig. 2b Fig. 2c Flow rate [ml / min] 40 130 200 Number of plates [N] 2-nitroacetanilide 503 524 495 Number of plates [N] 3-nitroacetanilide 465 465 445 Pressure [bar] 9 35 55

The results are in the 2a - 2c summarized. The usual flow rate of a 25 mm diameter column packed with particulate particles is 40 ml / min. The non-particulate carriers thus allow a much higher operating speed, resulting in significantly improved economics of separation tasks.

Example 2: Determination of the process parameters for one SMB separation of dimethyl phthalate and dibutyl phthalate

Dimethyl phthalate and dibutyl phthalate are applied and separated in different amounts: Conditions: sorbent: monolithic sorbent (C ₁₈ RP derivatized SiO ₂ ; 93 x 25 mm) mobile phase: Methanol / water (80/20; v / v) Sample volume: 50, 100-300, 600 μl detection: UV 300 nm Flow rate: 40 ml / min

For the components A (dimethyl phthalate) and B (dibutyl phthalate), the following modified Langmuir isotherms were found:

From the determined isotherms were prepared according to the in RM Nicoud, F. Charton, J. Chromatogr. 702 (1995) 97 using the simulation software HELP determines the separation conditions for the SMB separation: Column dimension [mm] 93 × 25 Number of columns 8th Flow rate feed [ml / min] 1.9 Feed concentration [g / l] 320 + 320 Flow rate recycling [ml / min] 44.1 Flow rate of raffinate [ml / min] 2.9 Flow rate of extract [ml / min] 21.8 Cycle switching time [min] 2.24 Concentration of raffinate [g / l] 209.7 Concentration extract [g / l] 27.89 Purity raffinate / extract > 99.9

Claims (2)

Process for the separation of at least two substances according to the "simulated moving bed" process using monolithic sorbents, characterized in that a) monolithic sorbents derivatized with separation effectors in the form of porous shaped bodies of SiO ₂ are used, which interconnected macropores and mesopores in the Have walls of the macropores, wherein the diameter of the macropores has a median value greater than 0.1 microns and the diameter of the mesopores has a median value between 2 and 100 nm, and b) the entire column bed is divided into cyclically connected individual columns, so that the total number of the columns is a multiple of 4, and between the individual columns are each 4 two-way valves, which represent a connection to the 4 each supply and discharge lines, and that for separation c) by repeatedly switching the valves after a defined time by one column unit in Direction of the fluid movement each individual column successively through all four zones until the supply and discharge lines return to their original position, so that with a suitable choice of the flow rate and cycle time of the valve circuits after several cycles a stationary state sets and d) the separated products in pure form can be removed as extract and Raffinatströme. Method according to claim 1, characterized in that that the flow rate in a column from 25 mm diameter to a value higher than 40 ml / min.