KR19990064154A - Heat-Treatment Separation and Dewatering Methods for Recovering Acid Products - Google Patents

Abstract

The present invention relates to a preferred method for separating the desired chemical product from other compounds in solution using heat-treatment chromatography on a solid adsorbent. The process of the present invention involves the chromatographic principle promoted by varying the operating temperature in the separation and eluting phases. Also described are methods of treating acid aqueous solutions for dehydrating and recovering acids in organic solvents such as alcohols.

Description

Heat-Treatment Separation and Dehydration Methods to Recover Acid Products

As prior art, research has long been underway in pursuit of their efficient and cost effective production route for the recovery and purification of acidic compounds such as carboxylic acids and other useful chemical products. For example, carboxylic acids such as citric acid and lactic acid are widely produced by large scale fermentation. Such fermentation methods provide the fermentation broth with the desired acid recovered and purified from these fermentation broths. In the case of high-volume manufacturing, it is not necessary to stress again that it is important to keep the unit cost at a minimum.

Recent recovery process studies have focused on using solid polymer adsorbent materials to recover carboxylic acids from fermentation broth. In this method, the fermentation broth is passed over an adsorbent adsorbing the carboxylic acid, and the carboxylic acid product is desorbed in a certain manner to provide the product. In general, various adsorbents and adsorption / desorption routes have been proposed.

For example, Kawabata et al. Describe a process for recovering carboxylic acids using US Pat. No. 4,323,702, a material whose main component is a polymeric adsorbent having a structure crosslinked with a pyridine backbone structure. The carboxylic acid is adsorbed to the adsorbent and then desorbed using a polar organic material such as an aliphatic alcohol, ketone or ester.

Kulprathipanja et al., US Pat. Nos. 4,720,579, 4,851,573 and 4,851,574, are neutral, nonionic, macroreticular, water-insoluble crosslinked styrene-poly (vinyl) benzenes, tertiary amine functional groups or pyridine Crosslinked acrylic or styrene resin matrices with functional groups attached, crosslinked acrylic or styrene resin matrices with aliphatic quaternary amine functional groups are taught. In their study, Kulpratipanya described "pulse tests" performed under isothermal conditions, which use acetone / water, sulfuric acid and water as desorbents.

South African Patent Application No. 855155, filed Jul. 9, 1985, describes a process for recovering product acids from their aqueous solutions. In the adsorption step, the acid-containing solution was subjected to vinylimidazole / methylene-bis-acrylamide polymer, vinylpyridine / tripetylolpropane tri-methacrylate / vinyltrimethylsilane polymer, vinylimidazole / N-vinyl-N Methylacetamide / methylene-bis-acrylamide polymer, Amberlite IRA 35 (Rohm & Hass-acrylate / divinylbenzene base-polymer containing dimethylamino group), or Amberlite IRA 93 SP (Rohm) & Hass) or Dowex MWA-1 or WRG-2 (Dow Chemical) (the last three of which are mentioned are styrene / divinylbenzene base-polymers containing dimethylamino groups) Let's do it. To desorb the acid, it is usually passed through a column at 90 ° C. However, the single-pass elution process described does not use thermal energy inefficiently and does not substantially maximize the resin's ability to highly concentrate the desorption solution. In addition, the resins used in this South African patent application are relatively thermally unstable and thus substantially decompose during the desorption process using hot water.

International Patent Application PCT / US92 / 02107 filed March 12, 1992 (published October 1, 1992, WO 92/16534) and PCT / US92 / 01986 filed March 12, 1992 (10 1992) Published January 1, WO 92/16490 (both filed by Reilly Industries, Inc.) describes the desorption of lactic acid and citric acid using steam or hot water from divinylbenzene-crosslinked vinylpyridine or other resins, respectively. Doing. The resin used has advantageous adsorption / desorption capacity and is very thermally stable under the hydrothermal desorption process described. Nevertheless, there is a need for an improved method of providing a desorption solution that is more efficient in using resins and the heat applied in desorption and has a higher concentration of product.

Another acid product recovery process has been proposed. For example, US Pat. No. 5,412,126 describes a process in which citric acid is adsorbed onto raw paper and then stripped using alkylamine. The material is then dehydrated and heat is removed to recover the free acid. US Pat. No. 5,032,686 describes a process for separating citric acid from sugars using acid resins, while US Pat. No. 5,382,681 first treats citric acid solutions containing other compounds with base to convert citric acid to trisodium citrate. After conversion, the basic medium is passed over the base resin to separate other compounds.

In light of these and other prior art in the art, there remains a need for an improved and effective method for purifying and recovering carboxylic acids and other useful products. The present invention has been carried out to meet these needs.

The present invention generally relates to techniques for recovering useful chemical products. More particularly, the present invention involves novel heat-enhanced chromatography techniques and relates to a very efficient and economical method for the selective recovery of the desired product from the liquid medium contained with other compounds.

1A and 1B are polyvinylpyridine polymers crosslinked under cold feed / elute (FIG. 1A) and heat feed / elute (FIG. 1B) REILLEX: for aqueous solutions of chromatographic citric acid / glucose mixtures chromatographed on HP. It is a figure which shows an elution profile.

FIG. 2 is a diagram showing the elution profile for an aqueous solution of a citric acid / glucose mixture chromatographed on REILLEX® HP, a polyvinylpyridine polymer crosslinked under cold feed and heat elution conditions.

3A and 3B show elution profiles for aqueous solutions of citric acid / glucose mixtures chromatographed on IRA-93 resin under cold feed / elute (3A) and heat feed / elute (3B) conditions.

4A and 4B are elution profiles for an aqueous solution of an acetic acid / glucose mixture chromatographed on REILLEX®, a polyvinylpyridine polymer crosslinked under cold feed / elute (4A) and heat feed / elute (4B) conditions. It is a figure which shows.

Figures 5A and 5B show the elution of an aqueous solution of the ascorbic acid / glucose mixture chromatographed on REILLEX® trademark HP under cold feed / elute (5A) and heat supply / elute (5B) conditions. It is a figure which shows a profile.

6A and 6B are elution profiles for an aqueous solution of a lactic acid / glucose mixture chromatographed on REILLEX®, a polyvinylpyridine polymer crosslinked under cold feed / elute (6A) and heat feed / elute (6B) conditions. It is a figure which shows.

Figures 7A and 7B are glucose / citric acid mixtures chromatographed with butanol as eluent on REILLEX® trademark HP, a crosslinked polyvinylpyridine polymer under cold feed / elute (7A) and heat feed / elute (7B) conditions. It is a figure which shows the elution profile with respect to the aqueous solution of.

FIG. 8 is a diagram showing the elution profile for an aqueous solution of a glucose / citric acid mixture chromatographed using ethanol as eluent on the crosslinked polyvinylpyridine polymer REILLEX® trademark HP.

FIG. 9 shows the elution profile for an aqueous solution of a glucose / phenol mixture chromatographed on REILLEX® HP, a polyvinylpyridine polymer crosslinked under cold feed and heat elution conditions.

10 is a side view showing a partial cross section of a continuous contact device that may be used in the present invention.

11 is a schematic diagram illustrating the port arrangement for the continuous contact device used in Example 12 below.

12 is a schematic diagram illustrating the port arrangement for the continuous contact device used in Example 13 below.

FIG. 13 is a schematic diagram illustrating a fork arrangement for a continuous contact device used in Example 14 below.

FIG. 14 is a diagram showing the elution profile for the aqueous solution of lactic acid chromatographed on REILLEX® HP, a polyvinylpyridine polymer crosslinked under isothermal conditions using methanol as eluent.

In order to improve understanding of the principles of the present invention, specific aspects and specific language of the present invention will now be described with reference. It is not intended to thereby limit the scope of the invention, but it should be noted that variations, modifications and applications of the principles of the invention as described herein are conventional to those skilled in the art of the invention.

As indicated above, one of the preferred embodiments of the present invention provides a heat-treatment chromatography separation method for separating the product from other compounds on the adsorbent resin and recovering the product. A feature of the process of the present invention is that it utilizes the traditional phenomena associated with the adsorption / thermal desorption process in adsorbent resin and chromatographic separations. Thus, in order to separate the acid product from the at least one other compound in the solution, a contact containing an adsorbent having a higher affinity for the acid than the at least one other compound and having an increased affinity for the acid as the heat is reduced Is to use a stand. A first solution containing an acid and another compound is introduced into the contact zone. In order to establish a high process capability and to utilize the adsorbent for chromatographic separation more effectively, it is preferred that the solution contains acid at a high concentration, for example optionally at a level substantially exceeding the acid adsorption capacity of the adsorbent. After introducing the acid / other compound containing solution, the second solution, for example, water, an aqueous solution containing acid but little other compound, or an organic solvent at a first temperature and at least one other compound Pass through the contact under conditions effective to establish the forward point of the acid separated from the contact. The advance point of the acid is then eluted from the contact using a liquid medium at a second temperature that is higher than the first temperature, for example 10 ° C., preferably at least 20 ° C., higher than the first temperature. In this process, the affinity of the adsorbent to the acid during the separation step is maintained at a relatively high level-to facilitate separation of the acid and one or more other compounds-and during the elution step, other compounds are separated from the acid advance point. The "heat-treatment" chromatography method then maintains the affinity of the adsorbent for the acid at a relatively low level to facilitate the recovery or elution of the acid from the contact zone, thereby increasing the amount of acid eluted over a given period of time. Is established. Thus, such preferred methods of the present invention can be based on the traditional adsorption / thermal desorption phenomena in chromatographic methods for effectively purifying acid products from one or more other compounds to recover highly concentrated product fractions. .

Generally, liquid-solid separation methods for recovering useful chemical products are known, and various adsorbent resins and suitable liquid eluents have been identified. Thus, those skilled in the art can readily select and use suitable adsorbent resins and eluent media in accordance with the present invention.

Generally speaking, the adsorbents used have the ability to adsorb the desired product and are stable under the processing conditions used as described below (ie, do not cause substantial degradation). Any adsorbent may be used as long as it can adsorb the desired product (including activated carbon, zeolite, etc.), but the preferred adsorbent for use in the present invention is a crosslinked polymeric adsorbent resin which is thermally and mechanically stable. And to provide an advantageous physical form. Bead-type adsorbent resins are preferred, particularly those having a particle size of about 20 to about 200 mesh, more particularly about 40 to about 120 mesh.

Various suitable polymeric adsorbents have been reported for the recovery of the desired adsorption product, such as carboxylic acids or other acids, and can be used as stationary phase in the heat-treated chromatography recovery process of the present invention. These polymeric adsorbents are typically formed through polymerization of one or more monomers, including crosslinking-monomers. The polymerization is carried out to give resin beads in a gel or macroreticular form. In addition, these resin beads can be chemically modified by adding ionic groups such as, for example, quaternary or acid salt groups to the resin. The resulting resin can thus be anionic, cationic or nonionic and has various physicochemical properties.

For example, resins that are reported to be suitable include basic polymeric materials such as neutral, nonionic, macroreticular, water-insoluble crosslinked styrene-poly (vinyl) benzenes, crosslinked pyridine-containing polymers, such as vinyl Pyridine polymers, crosslinked acrylic or styrene resin matrices with attached tertiary amine functionalities or pyridine functional groups, crosslinked acrylic or styrene resin matrices with attached aliphatic quaternary amine functionalities, and the like. See Kawabata and Kulprathipanja et al. al, patents mentioned in the background of the invention). These and numerous other polymers known in the art for use as adsorbents, such as base or acid ion exchange resins comprising styrene, acrylics, epoxy amines, styrene polyamines, and phenol formaldehyde, or nonionic adsorption resins Although suitable for use in the temperature conversion adsorption / desorption process according to the invention, crosslinked base polymers, such as crosslinked polymers containing N-aliphatic or N-heterocyclic tertiary amine functionalities, for example Preference is given to polymers containing dialkylamino or pyridine functional groups.

Particularly preferred pyridine-containing polymers are polyvinylpyridine polymers such as poly 2- and poly 4-vinylpyridine gels or macroreticular resins exhibiting bead form. These resins are preferably crosslinked at least about 2% with a suitable crosslinker such as divinylbenzene. More preferred resins are beaded vinylpyridine polymers, for example 2 to 50% crosslinked, for example poly 2- and poly 4-vinylpyridine polymers.

For example, more preferred resins are poly 2- and poly 4-vinylpyridine resins available from REillyEX® polymer series from Reilly Industries, Inc. (Indianapolis, Indiana). These REILLEX® trademarked polymers are generally crosslinked by at least 2% and exhibit good thermal stability and adsorption and desorption and other desirable properties as described herein. For example, preferred resins of this type exhibit at least about 200 mg citric acid desorption capacity per gram of polymer. Other preferred resins are available from the same source as the REILLEX® HP polymer series. These REILLEX® trademark HP polymers also exhibit advantageous capabilities and are highly recyclable. For more detailed information on these REILLEX® trademarked polymers, reference may be made to literature in the form of REILLEX® trademark reports 1,2 and 3, available from Reilly Industries, Inc.

Other resins such as AMBERLYST A-21, AMBERLITE IRA 68, or AMBERLITE IRA 93 resins from Rohm and Haas (Philadelphia, Pennsylvania), or DOWEX MWA-1 resins from Dow Chemical may also be used in the present invention. have. Among these resins, A-21 is crosslinked by divinylbenzene (at least 2%) and contains aliphatic tertiary amine functional groups (in particular, attached dialkylamino (dimethylamino) groups); IRA68 resin contains aliphatic tertiary amine groups, divinylbenzene-crosslinked acrylic matrix, and exhibits a gel form; IRA 93 and MWA-1 resins are based on divinylbenzene-crosslinked styrene matrices containing aliphatic tertiary amine groups and exhibiting macroreticulars. For further information regarding these and other similar resins that may be used in the present invention, reference may be made to literature available from the manufacturer.

The heat-treatment process of the present invention provides the particular advantage that the equilibrium concentration between the product of interest and the adsorbent changes as the temperature changes, for example to adsorb or inhibit the desired acid product at relatively low temperatures compared to high temperatures. This provides the advantage that the capacity of the adsorbent is substantially greater (i.e., 5% or more based on milliequivalents per gram of anhydrous adsorbent). Preferred products to be recovered in accordance with the invention are acids, especially acids having a pKa value in the range of about 2.0 to about 4.5. More generally, acids having a pKa range of about 2.0 to about 6.0 are suitable, with preferred groups having a pKa range of about 3.0 to about 5.0. Examples of acids that can be used in the present invention include aromatic acids such as phenol, salicylic acid, ortho-phthalic acid, meta-phthalic acid, benzoic acid, 3-chlorobenzoic acid; Alpha-hydroxy acids such as citric acid, lactic acid, dilactic acid, malic acid, mandelic acid, benzic acid, glyoxylic acid, glycolic acid, tartaric acid, formic acid, glutaric acid, fumaric acid, acetylacetic acid, acetic acid, succinic acid, itaconic acid; Pyridinecarboxylic acids such as nicotinic acid or isnicotinic acid; Piperidinecarboxylic acids such as isonifecotic acid; Inorganic acids such as phosphoric acid, sulfonic acid, tungstic acid, molybdate, gallium (III) ions, and mercury (II) ions. For further acids suitable for use in the present invention, reference is made to the acids identified in US Pat. Nos. 4,552,905, 4,323,702 and 5,412,126. In their recovery process according to the invention, these acids are for example other sugar-acidic compounds, including, for example, sugars, amino acids, amides (eg, on the separation of carboxylic acids from the corresponding amides), or natural or industrial processing. It can be separated from other similar compounds such as acids that occur in the middle.

Of particular interest in the present invention are the recovery of organic acids, in particular carboxylic acids such as aliphatic carboxylic acids, from the media produced by fermentation, ie fermentation of suitable carbon sources by microorganisms.

For example, substantial general purpose production of organic carboxylic acids such as citric acid and lactic acid is carried out by fermentation. In the case of citric acid, a carbon source such as corn sugar or molasses can be fermented using a suitable citric acid-producing bacterium or other microorganisms such as Aspergillus Niger to obtain broth. Lactic acid is produced using bacteria or other microorganisms that can form lactic acid upon carbon assimilation. Typically, other microorganisms can be used, such as fungi, but bacteria of the Lactobacillaceae family are used. For example, as generally taught in International Patent Application No. PCT / US 92/09938 filed on September 14, 1992 by Reilly Industries, Inc., published April 1, 1993, WO 93/06226. Likewise, fungi of the Rizopus family such as Rizopus oryzae NRRL 395 (United States Department of Agriculture, Peria, Illinois) can be used to produce substantially pure L + lactic acid. The selection and use of fermentation microorganisms suitable for producing fermentation broths containing organic acids, such as carboxylic acids, which can be treated in accordance with the present invention to recover acids are within the scope of the ability of those skilled in the art.

If carboxylic acid-containing fermentation medium is involved, it usually contains water, product acids, salts, amino acids, sugars, and other small amounts of various components. The fermentation medium as described above may be filtered to remove suspended solids prior to the adsorption step. In addition, according to the invention, the carboxylic acid-containing fermentation medium can be recovered from the ongoing carboxylic acid production fermentation, for example by WO 93/06226 published September 14, 1992, filed April 1, 1993. As described for lactic acid in PCT / US92 / 07738, the recovery step of the acid can be coupled to its fermentative production. In such a coupled method, the feed to the separation process may be part of the fermentation medium, preferably part of the fermentation medium after filtration or other processing steps suitable for the preparation of the feed for passing through the separation process of the present invention. Can be. The carboxylic acid may be recovered by a separation process as described herein, and the "waste" eluent stream deficient in carboxylic acid from the separation process may be recycled to the fermentor to recycle fermentation nutrients. Such a method can effectively reduce feedback inhibition of acid-producing cells by acid products, as is known to occur in, for example, lactic acid fermentation.

Various liquid eluents can be used in the present invention. Examples of these eluents include alcohols (eg, C ₁ -C ₅ alcohols such as methanol, ethanol, propanol, isopropanol, butanol and methylisobutyl carbinol), aromatic solvents such as ketones and esters or organic solvents such as polar organic solvents. , As well as an aqueous medium such as water (ie substantially pure water without added solute), an aqueous solution of an acid or base, such as an aqueous hydrochloric acid, sulfuric acid or sodium hydroxide solution, or a water / organic co-solvent such as a water / alcohol mixture There is a medium. Some preferred methods of the present invention provide a desorbent medium that is free of unnecessary solutes or co-solvents that can complicate the recovery of the desired product using water. Another preferred method of the invention uses organic solvents such as alcohols in such a way that the acid product is dehydrated and the acid product in the organic solvent is recovered. When alcohol is used in such a process, the product can be recovered in alcohol with a minimum amount of water (less than 20% by weight, preferably less than 10% by weight), for example for carboxylic acids (e.g. citric acid). The recovered product medium can then be reacted in an esterification process to yield the corresponding carboxylic acid ester or partial ester.

In general, the eluting step of the heat-treatment process of the present invention uses elevated temperatures relative to the separated acid, which is sufficient to effectively elute the product from the adsorbent resin. The specific elution temperature used depends on several factors such as the acid product of interest, the eluent used and the like. Temperatures below the boiling point of the eluent or above the boiling point are suitable. The elution temperature in a preferred method is generally about 50 ° C. or higher, more typically about 70 ° C. or higher, and typically about 90 ° C. or higher. In recovering a carboxylic acid such as citric acid or lactic acid, the desorption temperature is preferably about 90 ° C. or higher.

In preferred heat-treatment chromatography methods of the present invention, concentrated product feeds containing products at high levels, in some methods, product levels substantially exceeding the capacity of the adsorbent, for example, 20% or more of adsorption capacity. Using product concentrations in excess of 100%, as the feed passes through the column, it establishes a separator with more product present in the separator than the adsorbent can adsorb to the separator. On the other hand, the adsorption capacity of the product that is the target of the adsorbent can be expressed in a known form. It can be measured by luter analysis. It is to be understood that the specific product feed concentration used can be selected based on a variety of factors, for example to maximize the use of the resin and at the same time obtain a product stream with the necessary purity.

By using the concentrated feed as described above, the resin can be used more effectively for separation, and a significantly higher process capability can be achieved than in the method using the adsorption capacity of the adsorbent or the product loading below the adsorption capacity. For example, in the specific examples presented hereafter, in the process performed and described in connection with FIG. 12, using 50% citric acid (concentrations in excess of the resin's ability to be at least 200%), per gram of adsorbent (anhydrous) Achieve process capability in excess of 3 milliliters of citric acid. Using the adsorbent at such a high level reduces the adsorbent inventory requirements and increases the yield. These are obvious advantages that can be used in large scale separation processes.

Thus, in a more preferred method for separating citric acid from impurities such as sugars, a product feed is provided with a concentrated solution of citric acid, for example, a solution having a concentration above about 25%, more preferably above 30%. Use as. For example, a concentrated feed of citric acid can be obtained by initially concentrating citric acid-containing aqueous medium having a level of citric acid less than about 20% from fermentation. The concentration step can be carried out in an acceptable manner, for example by evaporating water from the medium. The concentrated medium with elevated citric acid concentration is then used as feed in the method of the present invention.

Other features of the present invention include relatively weak acids, such as lactic acid or acetic acid, as well as under the isothermal chromatography conditions as well as simultaneously discussed above while simultaneously dehydrating weak carboxylic acids having a pKa of at least 3.5, such as 3.6 to 6.0. Advantageous elution profiles can be obtained under the same heat-treatment conditions. Thus, as described in Example 13 below, an aqueous solution of weak acid can be added to the color separator through which a polar organic solvent, such as alcohol, is passed as eluent. Adsorbents in the separation band, preferably adsorbents containing tertiary amino groups, such as pyridinyl groups, have a higher affinity for acids than for water and yield eluates containing acids in alcohol solutions that are substantially free of water. The separation step is carried out in a manner. In this regard, as used herein, “substantially free” means that the alcohol solution containing the recovered acid product contains up to about 20% by weight of water. More preferably, the recovered alcohol solution contains less than about 10 weight percent water, most preferably less than about 5 weight percent water. Also, in a preferred method, the recovered alcohol solution contains the acid product at a high concentration relative to the injected concentration. For example, in a preferred method, the acid concentration in the recovered alcohol eluate is at least about 50%, more preferably at least about 75% in the acid aqueous feed.

A more preferred thermally managed dehydration process of the present invention feeds the feed of eluate medium containing the product to the separation step of the process. Such product-containing eluents, for example, products prior to the elution process to recover the product, can be used to effectively assist in the separation of other compounds from the acid product, while the presence of the product in the eluate can result in product in the final product stream. To increase the concentration. Thus, in a preferred process, a portion of the product eluent stream from the continuous recovery process is sent to a washing step to increase the concentration of product in the product stream.

Another aspect of the present invention relates to a process for treating a salt solution formed, which allows the weak acid and base to be recovered separately by interaction of the weak acid and base. Using a suitable eluent such as water, the solution is chromatographed at the contact object containing a polymer having a tertiary amine functional group, preferably a pyridine functional group, in an eluent separated from the contact zone from the advance point of the base in the eluent. Establish the forward point of weak acid. The eluent is passed through continuously (under isothermal conditions or heat-treatment conditions as generally described herein) to elute the advancing point of the weak acid and the advancing point of the base separately from the contact zone. This method can be used for the recovery of weak acids, such as lactic acid, produced by fermentation and neutralized with fermentation as the fermentation progresses or after fermentation. For example, in the case of lactic acid, the microorganisms used for its production are inhibited in the presence of low pH and lactic acid, so it would be advantageous to neutralize lactic acid with, for example, ammonia, calcium hydroxide (lime) or sodium hydroxide as it is formed during fermentation. Can be. Accordingly, lactate salts (eg, ammonium, calcium or sodium lactate) are included in the medium, which can be treated according to the method of the present invention to recover free lactic acid.

Advantageous methods of the invention are carried out using a Continuous Contacting Apparatus ("CCA"). For example, a continuous contact device useful in the present invention may be such as an ISEP or CSEP continuous contactor available from Advanced Separations Technology, Inc. (AST, Inc.), Lakeland, FL. US Patent 4,764,276, issued May 16, 4,808,317, issued February 28, 1989, and 4,522,726, issued June 11, 1985. A brief description of such CCA devices as described in these patents is given below. For further details regarding the design and operation of CCAs suitable for use in the present invention, refer to the aforementioned U.S. patents as well as documents available from AST, Inc., including "The ISEP ^™ Principle of Continuous Adsorption."

Preferred CCAs for use in the present invention are liquid-solid contact devices which include a plurality of chambers adapted to receive solid adsorbent material and which may provide together or separately contacting contacts for the method of the present invention. The chamber has a respective inlet and outlet, and a rotation is installed around the central axis such that a supply and outlet that operates with the inlet and outlet is passed through the chamber. In particular, liquid is individually supplied to the inlets of the top of these chambers through conduits connected to the valve assemblies of the top of the chamber, the valve assembly providing a number of supplies that work with the inlets of the chamber as it progresses. Similarly, the conduit connects the outlet at the lower end of each chamber to the valve assembly at the bottom of the chamber, which provides an outlet that works with the outlet as the chamber progresses. The valve assembly includes a movable plate having a slot that covers and does not cover the inlet as the plate is rotated into a carousel. By varying the size of the slot in the plate and the position of the slot, the flow from the supply conduit to the chamber and from the chamber to the exhaust pipe can be adjusted in a set manner. The movement of another plate on the plate may be a continuous or directed movement. The time for liquid to flow into and out of the chamber is a function of the chamber rotational speed around the central axis.

More specifically, preferred contact devices for use in the present invention are generally shown in FIG. The device comprises a rectangular frame 11 which supports the vertical drive shaft 12. The carousel 13 is mounted on the drive shaft for rotation. The carousel is processed on the shaft and the shaft is driven by a motor 14 mounted on the frame 11. A number of cylindrical chambers 15 (eg 30 chambers) are mounted vertically on the carousel 13. The chambers are preferably arranged in a twisted relationship around the carousel. Each chamber is filled with a resin or other suitable solid adsorbent material depending on the particular process to be performed. As shown on the left side of the fragment in FIG. 10, it is desirable to fill solid adsorbent material 16 at least about half the height of chamber 15. An arrangement is provided on each chamber 15 to insert and remove solid material through the top of the container. Pipe fixtures 17 and 18 are provided in the inlet and outlet openings on the top and bottom of each chamber 15. The upper valve body 19 and the lower valve body 20 are mounted on the drive shaft 12. Valve bodies 19 and 20 provide supply and discharge portions (eg 20 respectively). Each conduit 21 and 22 connects valve bodies 19 and 20 to respective upper and lower pipe fixtures 17 and 18 such that the supply and discharge of valve bodies 19 and 20 work with the inlet and outlet of chamber 15. Feed conduit 23 (also capable of discharge) is mounted on top of frame 11 and extends up from valve body 19. Similarly, discharge conduit 24 (also available) extends downward from lower body 19 to frame 11. In this way, as the carousel rotates and chamber 15 proceeds, the inlet and outlet of chamber 15 work in conjunction with the supply and discharge of valve bodies 19 and 20 to provide an advantageous means for rotating the liquid through chamber 15. do.

In accordance with an aspect of the present invention, it is preferred that the device of FIG. 10 be arranged to include a separation and elution zone. The separator may be operated normally such that the material of interest, for example citric acid, is separated from other compounds on the adsorbent resin contained in chamber 15 from the feed solution. In general, a feed solution containing citric acid or other product is passed countercurrently through the chamber 15 onto the resin. It should be noted that numerous parts of the CCA, marked as separation and elution, can be changed and determined to maximize the overall process economy. It should also be noted that the advantages of using the product stream in the separator as discussed above can be achieved by conveying the product fraction from the eluate to the separator. A detailed description of such an arrangement is discussed below in connection with FIGS. 11 and 12.

Accordingly, one of the preferred embodiments of the present invention is to provide a method for separating acids from one or more other compounds, which includes heat-treatment chromatography separation and elution steps. Thus, a preferred method of separating the acid from a mixture with other compounds is provided, which chromatographically separates the acid from the other compound on the adsorbent resin at a first temperature and then at least 10 ° C. higher than the first temperature from the adsorbent resin. The acid product is eluted at the second temperature. More preferred methods use a contacting zone containing an adsorbent which has a higher affinity for acids than one or more other compounds and which increases affinity for acids with decreasing temperature. A first solution containing an acid and another compound is introduced into the contact zone. In order to establish a high operating capacity, the solution may contain acid at a level substantially exceeding the acid absorption capacity of the adsorbent. Pass the second solution (eluent) through the contact. The second solution is passed under conditions effective to establish the advance point of the acid that is separated at the contact zone from the advance point of the one or more other compounds at the first temperature. The advance point of the acid is then eluted from the contact zone using a liquid at a second temperature, for example 10 ° C. or 20 ° C. higher than the first temperature. For this process, during the separation step, the adsorbent's affinity for the acid is maintained at a relatively high level, which retards the acid and facilitates separation of the acid from one or more other compounds, while during the elution step, the adsorbent The acid affinity of is maintained at a relatively low level, increasing the amount of acid eluted over a given period of time. Thus, a preferred method of the present invention may utilize the traditional adsorption / thermal desorption phenomenon in chromatographic separations to effectively purify acid products from one or more compounds and recover highly concentrated product fractions.

Particularly preferred methods of the invention use a continuous contact device comprising a plurality of resin-filled contact zones (eg, resin columns). A chromatographic separator is established that includes a plurality of contacting bands that together contain an amount of adsorbent sufficient to substantially separate the acid from other compounds. The chromatography separator is operated at a relatively low, first temperature. The elution zone establishes an elution zone that elutes the product acid once substantially separated from the other compound. The elution zone is operated at a second temperature that is higher than the first temperature. After the elution zone, it is desirable to cool the resin-filled contact zone (which is now virtually product free) to achieve the optimum temperature for the separator in the next cycle in a continuous contact device. The preferred cooling step is to pass the liquid medium at a lower temperature than the resin through the contact zone. The continuous contact device may be suitably valved to allow the contact stage to undergo a series of separation, heating, elution, and cooling steps and to perform the heat-treatment chromatographic separation process of the present invention.

According to another aspect of the present invention, a heat-treatment chromatographic separation process establishes a process for continuously processing a plurality of contact zones containing an adsorbent, wherein the processing exceeds the ability of the adsorbent to product. Is passed through a liquid medium, and the acid product is separated chromatographically from the other compound at a first temperature, followed by eluting the product at a second temperature at least 10 ° C. above the first temperature. In this and other aspects of the invention, first, the product-containing medium fraction from the processed contact zone can be included in the eluent used during the chromatographic separation step.

Another preferred aspect of the present invention provides a method for dehydrating and recovering an organic acid product from an aqueous solution, which provides a water-miscible solvent such as alcohol as a mobile phase under conditions in which the acid product is eluted into an alcohol solution that is substantially free of water. To chromatographically treat an aqueous solution of the acid product on the adsorbent resin. Such a method is advantageously carried out by providing a contacting zone containing an adsorbent having a higher affinity for acid than water and introducing an aqueous solution of acid into the contacting zone. The liquid alcohol is passed through the contacting zone under conditions effective to establish the forwarding point of the organic acid separated from the contacting zone from the forwarding point of water, and the elution solution containing the organic acid in the solution is eluted by eluting the forwarding point of the organic acid from the contacting zone. Wherein the eluate is substantially free of water (ie contains no more than about 15% by weight of water).

Another preferred chromatographic method for dehydrating organic acid products is

(a) providing a plurality of contact zones containing an adsorbent having a higher affinity for acid products than affinity for water,

(b) continuously processing the contact zone through a chromatographic separator, which performs a chromatographic process in which an acid eluent and an aqueous solution containing an acid are passed together through a contact zone to separate an acid from water, and

(c) After step (b), a contacting stage is passed through the elution stage so that an acid product is eluted from the at least one contacting zone in a solution of alcohol substantially free of water.

Another aspect of the invention relates to the discovery that a solution of salts of weak acids and bases such as ammonium lactate can be chromatographically treated on weak base resins to elute and recover the weak acids and bases separately. The present invention therefore also provides a chromatographic method for recovering weak acids and bases separately from salts of weak acids and bases. The method of the present invention provides a contacting zone containing a polymer having a tertiary amine functional group, introducing a salt solution into the contacting zone, and establishing an advance point of the weak acid in which the eluent is separated at the contacting point from the advancement point of the base. Passing through the contact under effective conditions. Continue to pass the eluent so that the forward point of the weak acid and the forward point of the base are eluted separately from the contact zone. This method is particularly useful for recovering weak acids that are produced fermentatively and neutralized so that fermentation actually continues. For example, in the case of lactic acid, the microorganisms used for its production are typically inhibited at low pH and in the presence of free lactic acid to neutralize the lactic acid formed during fermentation with ammonia. The ammonium lactate is thus contained in the medium, which can be treated according to the method of the present invention to recover free lactic acid.

The heat-treatment method of the present invention allows the product to be recovered in concentrated liquid medium, allows efficient use of thermal energy during recovery, and also operates in an arrangement that provides high performance and reduces the requirements of the adsorbent invention. do. The present invention also provides a process that is easy to work with and that can be used to recover various desired products in a concentrated solution. Further preferred embodiments, features and advantages of the invention will be apparent from the following description.

Examples 1-11

Common way:

For these examples, a series of pulse tests are performed to demonstrate applicability to various acids of heat-treated chromatography using different tertiary amine-containing polymers. A column 60 cm in length and 2.54 cm in diameter provides respective feed lines for the eluent and the acid product feed. The column is then unjacketed or jacketed with a thermostat, as shown in the description of the particular embodiment. While the eluent feed line includes a heat exchanger to control the temperature of the eluent feed to the column, as shown, the aqueous acid product / glucose mixture solution is fed at room temperature. Unless otherwise indicated, the acid product is present at 50% by weight, the glucose at 2% by weight, and 100 g pulses of product / glucose feed are provided to the column and the loading on the column is per g of resin, unless otherwise indicated. 3 million equivalents of acid. For column preparation, the slurry is loaded with a suitable resin and pre-washed with water to remove air bubbles. Equilibrate the system by fixing the thermostat and recycling the eluent through the bed. The feed mixture is pumped onto the bed and the eluent is pumped immediately. Samples eluting from the column are collected, typically in 1/10 bed volume (BV) for the first three BVs, and then 1/2 BV samples for the remainder of the collection period. Samples are analyzed using HPLC and appropriate standards. In each run, the resin volume is 350 ml.

Examples 1A and 1B

The citric acid / glucose product aqueous solution feed is treated using water as eluent in a non-jacketed column at a flow rate of 20.3 ml / min on REILLEX® HP resin (30-60 mesh). For Example 1A, the temperature of the feed and the eluent is 25 ° C. For Example 1B, the temperatures of the feed and the eluent are 75 ° C. and 86 ° C., respectively. The results are shown in FIGS. 1A and 1B, respectively. As shown in FIG. 1A, good separation of glucose and citric acid was achieved at relatively low temperatures, but the peak concentration of citric acid was only about 3%, which was substantially trace. On the other hand, as shown in Fig. 1B, at a relatively high temperature, the peak concentration of citric acid was much higher but the separation from glucose was relatively poor. Thus, the present invention has particular advantages and can be applied to the separation, whereby both good citric acid separation and elution profile can be obtained using low temperature and high temperature applied to shift the citric acid advance point after the substantial separation has been carried out during the separation. have.

Example 2

The citric acid / glucose product feed is treated with water as eluent at a flow rate of 20.8 mL / minute in an unjacketed column on REILLEX® HP resin (30-60 mesh). The acid product feed temperature is 25 ° C., and the subsequent small amount of water feed is 25 ° C. The eluent (water) is then fed at 86 ° C. In this way, relatively low temperatures are maintained on the product / glucose advance point during its migration through the column in the separation phase, while relatively high temperatures are in the region of the citric acid advance point during elution. Specific results are shown in FIG. 2, which shows both an improved citric acid elution profile for FIG. 1A and an improved separation for FIG. 2B. Thus, the advantages of separation and product recovery are provided by thermal management of the column during the separation and elution steps.

Examples 3A and 3B

The citric acid / glucose product feed is treated on IRA-93 resin at a flow rate of about 21 ml / min in a jacketed column using water as eluent. For Example 3A, the temperature of the feed and the eluent is 25 ° C. For Example 3B, the temperatures of the feed and the eluent are 85 ° C. and 86 ° C., respectively. The results are shown in Figures 3A and 3B, respectively. In general, as shown in Figures 1A and 1B, better separation occurs under cold feed / eluent conditions, while elution profile of citric acid occurs more preferably under higher temperature feed / eluent conditions. It has also been demonstrated that heat-treatment chromatography can be used as in the present invention to provide advantages in separation.

Examples 4A and 4B

The 15% acetic acid / 1% glucose product feed is treated on REILLEX® HP resins (30-60 mesh) using water as eluent in a jacketed column. 60.5 g of the feed is placed on a column and the loading of the resinous phase is 2 milliequivalents of acetic acid per gram of resin. For Example 4A, the flow rate is 20.6 ml / min and the temperature of the feed and the eluent is 25 ° C. For Example 4B, the flow rate is 22.0 ml / min and the temperature of the feed and the eluent is 85 ° C. and 86 ° C., respectively. The results are shown in Figures 4A and 4B, respectively, which represent dissolution profiles illustrating the applicability of the present invention to separation.

Examples 5A and 5B

The 10% ascorbic acid / 1% glucose product feed is treated on REILLEX® HP resins (30-60 mesh) using water as eluent in a jacketed column. A total of 205.5 g of feed is fed to the column, and the loading of the dendritic phase is 0.72 milliequivalents of ascorbic acid per g of resin. For Example 5A, the flow rate is 20.6 ml / min and the feed and eluent temperatures are 25 ° C. For Example 5B, the flow rate is 22.0 ml / min and the temperature of the feed and the eluent is 85 ° C. and 86 ° C., respectively. The results are shown in Figures 5A and 5B, respectively, which similarly illustrate the applicability of the present invention to the separation and recovery of ascorbic acid.

Examples 6A and 6B

The 18% lactic acid / 1% glucose product feed is treated on REILLEX® HP resins (30-60 mesh) using water as eluent in a jacketed column. The loading of the dendritic phase is 3 milliliter equivalents of lactic acid per gram of resin. For Example 6A, the flow rate is 20.0 ml / min and the temperature of the feed and the eluent is 25 ° C. For Example 6B, the flow rate is 21.6 ml / min and the temperature of the feed and the eluent is 85 ° C. and 86 ° C., respectively. The results as shown in Figures 6A and 6B show an elution profile illustrating the applicability of the present invention to lactic acid separation.

Examples 7A and 7B

The citric acid / glucose product aqueous solution feed is treated on a REILLEX® HP resin (30-60 mesh) at a flow rate of 20 ml / min in a jacketed column. For Example 7A, the temperature of the feed and the eluent is 25 ° C. For Example 7B, the temperature of the feed and the eluent is 85 ° C. The results are shown in Figures 7A and 7B, respectively. As shown in FIG. 7A, at relatively low temperatures glucose and water on the one hand and citric acid on the other hand were well separated. As shown in Figure 7B, relatively high temperatures can be used to increase the peak concentration of citric acid. Thus, the present invention, which uses a relatively low temperature during the recovery step using a relatively low temperature, can advantageously be applied to the separation process and also dehydrates the product feed and recovers substantially in alcohol. To provide the product. Such products can be reacted, for example, to esterify citric acid.

Example 8

The exception is the use of ethanol as eluent to repeat Example 7A, the results are shown in FIG. These results indicate that citric acid is well separated from water and glucose. Repeating Example 7B, which differs in using ethanol as eluent, shows that the citric acid recovery profile is improved but separation is reduced. Thus, the applicability of heat-coated chromatography using ethanol to provide a dehydrated and purified acid product is demonstrated.

Example 9

A 6.5% phenol / 1% glucose product aqueous solution feed was used in a jacketed column, using water as eluent, under the cold feed and thermal eluent conditions as generally described in Example 2 above. 30 to 60 mesh). The results are shown in Figure 9, demonstrating that heat-controlled chromatography can be applied to the separation and recovery of phenols.

Example 10

The pH of the 16.1% lactic acid aqueous solution was adjusted to pH6.45 using ammonia water to use REILLEX® under cold feed and thermal eluent conditions as generally described in Example 2 above using water as eluent in a jacketed column. Treatment is performed on HP resins (30 to 60 mesh). The results demonstrate that heat-coated chromatography can be applied to decompose acid salts (ammonium lactate) into free acids (lactic acid) and free bases (ammonia). Ammonium lactate is also degraded under cold eluent conditions.

Example 11

Cold feed and thermal eluate as described generally in Example 2 above using water as an eluent on REILLEX® HP resins (30 to 60 mesh) using a 1% nicotinic acid / 30% nicotinamide product aqueous solution feed Process under conditions. The results demonstrate that heat-assisted chromatography can be applied to separate pyridinecarboxylic acids such as nicotinic acid from the corresponding amide (eg nicotinamide).

Example 12

This process is provided for comparison purposes. 11 illustrates an arrangement using CCA as described above. The process using the arrangement of FIG. 11 is performed in an ISEP L100 pilot-scale CCA available from AST, Inc. The operation of the device is essentially as described above for the CCA, which has a static branch having 20 ports and a carousel of 30 resin columns working with the port. The generated valve operation separates the column from the different fluid streams while maintaining continuous flow through the port. The L100 pilot unit has a glass column with a polypropylene cap (1 inch inner diameter, 350 ml volume) and 70 mesh screening to contain the resin. The upper and lower valve assemblies connected to the column are made of polypropylene and 316 stainless steel. Connections through the device consist of standard polypropylene, polyethylene or Teflon tubes all 1/4 inch in diameter. The heat exchanger described in FIG. 11 is either a tube-and-shell or plate-and-frame heat exchanger. Low pressure steam is used for heating and cooling water (about 15 ° C) or tap water (room temperature) is used for cooling. All solutions are transferred using peristaltic pumps with norphrene tubes of various sizes (14-18). The tubes are insulated to limit heat transfer with the environment.

The temperature is measured on a Yokogawa HR 1300 chart recorder using a 1/4 inch stainless steel J-type thermocouple into the line of the connection panel. Pressure is measured in-line at the connection panel using a stainless steel gauge. The flow rate is measured manually by weight over time (typically 30 minutes) at various inlet or outlet ports.

Citric acid feed solution is prepared using anhydrous USP / FCC grade citric acid, maltose monohydrate and anhydrous D-(+)-glucose, mixed anomers, and deionized water. These solutions are prepared immediately before use to avoid potential bacterial growth.

REILLEX HP: The trademarked polymer is obtained from Reilly Industries, Inc. in water moistened form. The resin is passed through a sieve to obtain beads having a size range of 30 to 60 mesh. The resin is then immersed in 15% citric acid solution overnight to transfer to an L100 glass column. Each column is pre-washed with several times the bed volume of water to remove fines and then connected to L100. A total of 10.5 liters of citric acid swelled resin are charged to 30 columns, which equates to about 7.55 liters of water swelling resin or 2.10 kg of anhydrous resin.

11 shows a schematic diagram of the preferred port arrangement in L100 used in citric acid performance. The column rotation of L100 flows countercurrently to the solution, ie from right to left in FIG. Measurement temperature, flow rate and centrifugation, flow pattern through the column are also shown in FIG. Briefly describing the arrangement, the flow pattern through the column is generally bottom flow, and for cold citric acid the adsorption is carried out in ports P5-P13, washed in P1-P4, and hydrothermal desorption in ports P14-P17. Ports P10-P13 are used for cooling down the resin after the desorption step, while ports P18-P19 are used to preheat the loaded resin before the desorption step. Port 20 is used to push the remaining tax solution from the resin column.

More specifically, the citric acid feed solution is fed from the tank 30 to the port P5 via a heat exchanger 32 (provided for cooling) using a pump 31. The stream leaving port P5 is fed to feed intermediate tank 33. The solution from the feed intermediate tank 33 is supplied to ports P6 and P7 in a parallel flow arrangement via a heat exchanger 35 (provided for cooling) using a pump 34. Streams outside P6 and P7 are fed to ports P8 and P9 in a parallel flow arrangement through heat exchanger 36 (provided for cooling). Streams leaving ports P8 and P9 are fed to a precooling / disposal intermediate stage tank 37. The solution from tank 37 is fed to ports P10 and P11 via heat exchanger 39 (provided for cooling) using pump 38, and the stream exiting ports P10 and P11 is directed back to tank 37. The “pump-around” provides preliminary cooling of the resin beads prior to introducing the resin beads into the citric acid adsorption step. Waste tank overflow also occurs in tank 37.

In the case of the desorption step, desorption medium, for example water, is fed from feed tank 40 to pumps P12 and P13 in a parallel flow arrangement. The stream exiting ports P12 and P13 flows into the strip intermediate tank 42. Pump 43 supplies solution from tank 42 through heat exchanger 44 (provided for heating) and back to tank 42. The pump-around through a heat exchanger heats the solution in the desorption process tank 42. It should be noted that the strip intermediate stage tank 42 and the other tanks used in this arrangement are preferably open to the atmosphere. This allows the gas released from the solution, in particular the gas released upon heating, to leak out before being introduced into the resin column. This is advantageous because gas flow through the resin beads can create channels that can interfere with the efficient operation of the device.

The heated solution from the strip intermediate stage tank 42 is fed to ports P14 and P15 of parallel flow using a pump 45. Streams discharged from P14 and P15 are collected in the midstrip intermediate stage tank 46. The material in tank 46 is also pumped around using pump 47 and heat exchanger 48 (provided for heating). The material from tank 46 is also fed to ports P16 and P17 in a parallel flow arrangement to collect the corresponding discharge stream in the preheat / product intermediate stage tank 49. The material in tank 49 is also pumped around using pump 50 and heat exchanger 51 (provided for heating). Some of the material in tank 49 is recovered as overflow product. The other fraction is fed to ports P18 and P19 using pump 52 and the corresponding discharge stream is fed back to tank 49. Pump-around through P18 and P19 preheats the resin beads before they are introduced into the desorption stage of the process. Another fraction of the material in tank 49 is fed to port P20 using pump 53, which also preheats the resin beads to some extent at P20.

In an important aspect of the invention, the stream discharged from port P20 is fed to the washing stage of the process via heat exchanger 54 (provided for cooling). Specifically, the port P20 discharge stream is fed to ports P1 and P2 of the plain flow arrangement. In the described and preferred arrangement, the product stream from port P20 is provided only as a detergent during the washing process. However, it should be appreciated that the product stream can be used with other detergents, such as water, which are fed to the washing step. The discharge stream collected from ports P1 and P2 is fed to ports P3 and P4 in a parallel flow arrangement. Thus, at ports P1 to P4, the resin beads loaded with the product, for example citric acid, are washed to remove non- or less-adsorbed material such as sugars. The discharge streams from ports P3 and P4 are collected in feed intermediate tank 33, where they are mixed with the citric acid feed released from port P5 and processed together as discussed above.

In the process using the arrangement of FIG. 11, the L100 unit is operated continuously for 3 hours prior to collecting the sample to encourage the system to reach equilibrium or near equilibrium conditions prior to sampling. The resulting sample is collected over 30 minutes to have proper representation and, if one or more samples are to be taken, shake for rotational speed so that the stream does not originate repeatedly from the same column. In this run, extending over 28 hours, a 14.7% citric acid feed containing 0.43% glucose and 2.03% maltose is fed to the system. In some important points in the system for this implementation the flow rate and temperature of the flowing solution is described in FIG. The product stream contains an average of 9.73% citric acid (96% recovery) and removes 94% glucose and 97% maltose. In another similar process where there is no heat exchanger 32 and thus cooling of the feed to column 5 is omitted, the product stream contains 9.76% citric acid (98% recovery) and the removal rates of glucose and maltose are 96% and 98%, respectively. to be.

Example 13

Figure 12 provides a schematic diagram of the L100 arrangement that can be used in the method of the present invention. The arrangement is similar to that shown in FIG. 11, and therefore conventional components need not be described again. However, the arrangement of FIG. 12 is arranged for the advantageous performance of a process using heat-treatment chromatographic separation and elution methods using product loadings substantially exceeding the effective capacity of the adsorbent. Comparing Figure 12 with Figure 11, one finds an increase in the number of ports provided for passing a portion of the product stream on the product-loaded columns (ports P19-20 and P1-6) columns. This increase provides additional separation power, even at higher product loadings, as impurities in the feed stream are removed from the column prior to the heated desorption steps (ports P13-P18). As in FIG. 11, the measured temperature and flow rate are shown in FIG. 12. The concentrations of product (citric acid) and impurities in the various feeds / eluents during the process are also shown in FIG. 12. As can be seen, certainly, using a feed of 50% citric acid with an easily carbonizable substance (RCS) level of 0.486, recover the product stream with a citric acid concentration of 20.9% and an RCS level of only 0.073. . Thus, a product stream with very citric acid and low RCS content is obtained. In addition, the process described in conjunction with FIG. 12 had a much higher working capacity than that described with respect to FIG. 11, wherein the process described in connection with FIG. 11 had 1.3 milliliter equivalents of citric acid per gram of anhydrous resin ) And about 3 meq / g anhydrous resin described in connection with FIG. This increase in work capacity can be used to significantly reduce resin inventory and equipment size, significantly improving yield and processing economy.

Example 14

13 is a schematic diagram illustrating port arrangements that may be used in a CSEP device (which is also available from Advanced Separations Technologies, Inc.). The CSEP device is more optimal for chromatographic separations than the ISEP device described above and contains 20 columns and 20 ports, with columns indexed continuously through the ports. As can be seen in Figure 13, the CSEP setup described generally includes a counterflow, bottomflow arrangement, where the feed parallel to the port (as in the ISEP arrangement above) is avoided to most effectively utilize the separation force of the resin inventory. Do it. Feed to port P1 is part of the acid-containing product stream from port P20 (discussed later). After releasing the column associated with port P1, the feed is passed through a heat exchanger 60 provided for cooling and then through ports P2-P5 in countercurrent. The stream is then combined from feed solution storage tank 61 with feed solution pumped by pump 62 (e.g. containing 50% citric acid and sugar impurities) to port P6 via heat exchanger 63 provided for cooling. Pass it through. The solution is passed in a countercurrent fashion through ports P7-P9 and then through port heat exchanger 64 provided for cooling to port P10. The stream releasing port P10 is relatively diluted in acid, but the product is concentrated in impurities (eg sugars) and sent to the waste.

Water or other liquid is pumped from storage tank 65 into port P11 via heat exchanger 67 provided for cooling via pump 68. The stream leaving port P11 is passed through a pre-cooled intermediate tank 68. A portion of the solution in tank 68 is pumped to port P12 and back to tank 68 via heat exchanger 70 provided for cooling via pump 69. This pump around at port P12 cools the resin. The solution is also fed from tank 68 countercurrently through ports P13-P14 and then through the heat exchanger 71 provided for heating to the counters P15-P17 in countercurrent flow. The stream exiting port P18 is the feed to the preheating intermediate tank 73. A portion of the solution in tank 73 is passed through port P19 upstream through heat exchanger 74 provided for heating and then fed back to tank 73. This pump around at port P19 heats the resin. Some of the material in tank 73 is passed downstream through port P20. The stream exiting P20 is a concentrated solution of the desired acid (eg citric acid), essentially free of impurities (eg sugar) present in the original feed. A portion of the discharged stream is collected as product and the other is fed to port P1 as discussed above.

The CSEP arrangement of FIG. 13 shows other compounds of the product acid (e.g. citric acid), even when supplied at levels substantially exceeding the adsorption capacity of the solid adsorbent (e.g. REILLEX HP resin as described above) in the column to acid. The containing solution can be effectively processed and concentrated. Thus, the process of the present invention is based on both chromatography and traditional adsorption / thermal desorption phenomena, which significantly reduces adsorbent requirements in commercial processes and results in highly concentrated product fractions.

The ports and other process arrangements shown in FIG. 13 are illustrative and other arrangements may be used to practice the invention herein. For example, the number of columns described as separation or purification zones and elution zones may vary depending on processing and / or product requirements. For example, in FIG. 13, a buffer band may be included using one or more ports between ports P10 and P11. It is also to be understood that the invention may be practiced by varying the position of the heat exchanger (provided for heating or cooling) during operation.

Example 15

Fill a glass column (5.8 cm x 75 cm) with 1500 ml of REILLEX HP resin, refine with water to remove air, then replace water with methanol. A 13 wt% aqueous lactic acid solution containing 1.29% glucose is pumped onto the column and immediately eluted with methanol at a flow rate of 100 ml / min. The process is carried out at 25 ° C. A sample of the eluent is collected and analyzed to produce a plot of the supplied eluent of the concentration of each component versus the bed volume. The results are shown in FIG. 14, demonstrating that lactic acid is separated from almost all amounts of water, providing a major cleavage of relatively highly concentrated lactic acid in glucose and methanol. This demonstrates that a chromatographic dehydration process with an alcohol eluent provides a highly desirable lactic acid elution profile even when performed under isothermal conditions. Thus, aqueous solutions of other similarly weak acids, such as lactic acid or acetic acid, can be advantageously treated under isothermal conditions in a CCA flow arrangement as shown in FIGS. 12 and 13 to dehydrate and recover acids in high concentrations in alcohol solvents.

While the present invention has been described and described in detail with the drawings and the foregoing description, it is to be understood that the invention is not to be limited in any way for illustrative purposes only, and has been shown and described with respect to the preferred embodiments thereof, that all changes and modifications within the spirit of the invention should be protected. shall.

All publications cited herein are indicative of skill level in the art and are incorporated herein by reference as if each were individually incorporated by reference and fully described.

Claims (41)

The acid is chromatographically separated from the other compound on the adsorbent resin at a first temperature and then eluted with the acid product from the adsorbent resin at a second temperature at least 10 ° C. higher than the first temperature. Heat-treatment method for recovering acid from the mixture. The acid of claim 1 wherein the acid is phenol, salicylic acid, ortho-phthalic acid, meta-phthalic acid, benzoic acid, 3-chlorobenzoic acid, citric acid, lactic acid, dilactic acid, malic acid, mandelic acid, benzyl acid, glyoxylic acid, glycolic acid, succinic acid, From the group consisting of tartaric acid, formic acid, glutaric acid, fumaric acid, acetylacetic acid, acetic acid, itaconic acid, sulfonic acid, tungstic acid, molybdate, pyridinecarboxylic acid, piperidinecarboxylic acid, gallium (III) ions, and mercury (II) ions The method chosen. The method of claim 2 wherein the acid is a carboxylic acid. The method of claim 3, wherein the acid is citric acid or lactic acid. The method of claim 4, wherein the product is citric acid. The process of claim 1 wherein the adsorbent is a crosslinked polymer resin containing tertiary amine groups. The method of claim 4 wherein the adsorbent is a crosslinked polymer resin containing tertiary amine groups. 8. The method of claim 7, wherein the adsorbent is a pyridine-containing polymer resin. 8. The method of claim 7, wherein the polymer resin is crosslinked with divinylbenzene. The method of claim 8, wherein the polymer resin is crosslinked with divinylbenzene. The method of claim 10 wherein the polymer resin is divinylbenzene crosslinked poly-2-vinylpyridine or poly-4-vinylpyridine. The method of claim 11, wherein the resin is in the form of macroreticular beads. The method of claim 12, wherein the resin is crosslinked from about 2% to 50% by weight with divinylbenzene. The method of claim 13, wherein the product is citric acid. The method of claim 1 wherein the eluent is used during chromatography separation containing an amount of acid. The method of claim 1 wherein the acid is provided in an aqueous solution by a chromatography separation step and the acid is dehydrated using an alcohol eluent during the chromatography separation. The method of claim 1, wherein the other compound is a sugar, an amino acid, or an amide. 18. The method of claim 17, wherein the acid is pyridinecarboxylic acid and the other compound is the corresponding amide of pyridinecarboxylic acid. 18. The method of claim 17, wherein the acid is nicotinic acid and the other compound is nicotinamide. The method of claim 17, wherein the acid is an acid produced by fermentation and the other compound is an amino acid or a sugar. The method of claim 20, wherein the acid is citric acid. The method of claim 20, wherein the acid is lactic acid. Providing a contact zone containing an adsorbent which has a higher affinity for acids than for one or more other compounds, which increases with decreasing temperature; Introducing a first solution containing an acid and at least one other compound into the contact zone; Passing the second solution through the contacting zone at a first temperature and under conditions effective to establish an advancement point of the acid that is separated at the contacting zone from the forwarding point of the at least one other compound; A process for separating acid from one or more other compounds in a solution, characterized by eluting the advance point of the acid from the contacting zone at a second temperature at least 10 ° C. above the first temperature. (a) providing a plurality of contacting zones containing adsorbents having a higher affinity for acid products than other compounds, the affinity of which increases with affinity with acids as the temperature decreases; (b) the contact zone is continuously passed through a chromatography separator, which carries out a chromatography process of passing the eluent and the product solution containing the acid and other compounds together through a contact zone to separate the acid from the other compound at a first temperature. Processing; (c) after step (b), the contact zone is continuously processed through an elution zone to elute the acid product from at least one contact zone at a second temperature at least 10 ° C. higher than the first temperature, Heat-Assisted Chromatography Method of Separating Acid Products from Other Compounds. The method of claim 24, wherein the eluent contains an amount of acid. A method of dehydrating and recovering an organic acid product from an aqueous solution, characterized in that the aqueous solution of the acid product is chromatographed on the adsorbent resin using alcohol as the mobile phase under conditions in which the acid product elutes in a substantially water free alcohol solution. Providing a contact zone containing an adsorbent having a higher affinity for acid than water; Introducing an aqueous solution of acid into the contact zone; Passing liquid alcohol through the contact zone under conditions effective to establish the advance point of the organic acid that separates at the contact zone from the advance point of water; A process for dehydration of an organic acid, characterized in that the elution point of the organic acid is eluted from the contacting zone to provide an eluent substantially free of water containing the organic acid to the solution in alcohol. (a) providing a plurality of contact zones containing adsorbents having a higher affinity for acid products than water; (b) continuously processing said contact zone through a chromatography separator, carrying out a chromatography process of separating an acid from water by passing an aqueous solution containing an alcohol eluent and an acid together through said contact zone; (c) after step (b), the contacting zone is continuously processed via an elution zone to elute the acid product from at least one contacting zone in an alcohol solution substantially free of water, thereby dehydrating the organic acid product. Chromatography Method. 29. The method of any of claims 26, 27 or 28, wherein the acid is a carboxylic acid. The method of claim 29, wherein the carboxylic acid is lactic acid. 30. The method of claim 29, wherein the alcohol is selected from the group consisting of methanol, ethanol, propanol, isopropanol, butanol and methylisobutyl carbinol. 30. The method of claim 29, wherein the alcohol solution contains less than 5 weight percent water. Providing a contact zone containing a polymer having a tertiary amine functional group; Introducing a solution of salt into said contacting zone; Passing the eluent through the contacting zone under conditions effective to establish the advancement point of the weak acid separated from the contacting point from the advancement point of the base; Chromatographic method for recovering weak acid and base separately from salts of weak acid and base, characterized in that eluting the forward point of the weak acid and the forward point of the base separately from the contact zone. The method of claim 33, wherein the polymer contains a pyridine group. 34. The method of claim 33, wherein the weak acid has a pKa of about 3-5. 36. The method of claim 35, wherein the weak acid is an acid produced by fermentation. The method of claim 36, wherein the weak acid is lactic acid. 38. The method of claim 37, wherein the salt is sodium lactate, calcium lactate or ammonium lactate. The method of claim 38, wherein the salt is ammonium lactate. 40. The process of any one of claims 33 to 39, wherein the acid is eluted at a temperature higher than the temperature used in the step of passing the eluent. 40. The process of any one of claims 33 to 39, wherein the acid is eluted at a temperature substantially equal to the temperature used in the step of passing the eluent.