WO1996008464A1 - Process to produce aminocarboxylic acids containing low residual salt - Google Patents
Process to produce aminocarboxylic acids containing low residual salt Download PDFInfo
- Publication number
- WO1996008464A1 WO1996008464A1 PCT/US1995/011093 US9511093W WO9608464A1 WO 1996008464 A1 WO1996008464 A1 WO 1996008464A1 US 9511093 W US9511093 W US 9511093W WO 9608464 A1 WO9608464 A1 WO 9608464A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- aqueous
- acid
- solution
- aminocarboxylic acid
- alkali metal
- Prior art date
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C227/00—Preparation of compounds containing amino and carboxyl groups bound to the same carbon skeleton
- C07C227/38—Separation; Purification; Stabilisation; Use of additives
- C07C227/40—Separation; Purification
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C227/00—Preparation of compounds containing amino and carboxyl groups bound to the same carbon skeleton
- C07C227/14—Preparation of compounds containing amino and carboxyl groups bound to the same carbon skeleton from compounds containing already amino and carboxyl groups or derivatives thereof
- C07C227/18—Preparation of compounds containing amino and carboxyl groups bound to the same carbon skeleton from compounds containing already amino and carboxyl groups or derivatives thereof by reactions involving amino or carboxyl groups, e.g. hydrolysis of esters or amides, by formation of halides, salts or esters
Definitions
- PROCESS O PRODUCE AMINOCARBOXYLIC ACIDS CONTAINING LOW RESIDUAL SALT
- This invention pertains to a method to produce aminocarboxylic acids containing low residual salt, and more particularly to methods of producing aminocarboxylic acids from an aqueous solution of an alkali metal salt of the aminocarboxylic acid.
- Aminocarboxylic acid salts can be synthesized by a number of known methods. Previously, the salts of certain aminocarboxylic acids had been converted to aminocarboxylic acids by using conventional acid crystallization methods or by electrochemical processes. These methods were expensive and/or not well suited because of the relatively high water solubility of the acid in the presence of sodium ions. Thus, using conventional methods, the production of aminocarboxylic acids cost about three times what their corresponding salts cost.
- N- (hydroxyethyl)ethylenediaminetriacetic acid has general broad applications as an industrial cleaner, for boiler cleaning and treatment, and as a micronutrient. Further, technology is needed to recover HEDTA acid from spent boiler cleaning applications.
- aminocarboxylic acid which has had one or more of its ionizable hydrogen atoms (on a COOH group) replaced by an alkali metal such as sodium or potassium to form a salt.
- aminocarboxylic acids salts are converted into their respective aminocarboxylic acids, including N- (hydroxyethyl)-ethylenediaminetriacetic acid (hereinafter referred to as HEDTA acid) , diethylenetriaminepentaacetic acid, hydroxyethyliminodiacetic acid, nitrilotriacetic acid, and glycine.
- HEDTA acid N- (hydroxyethyl)-ethylenediaminetriacetic acid
- diethylenetriaminepentaacetic acid diethylenetriaminepentaacetic acid
- hydroxyethyliminodiacetic acid hydroxyethyliminodiacetic acid
- nitrilotriacetic acid and glycine.
- Diafiltration is a constant volume washing process in which a membrane is used to selectively remove smaller molecules and ions, and/or exchange solvent while retaining the larger molecules and ions in the feed solution.
- the following patents are representative of the pertinent art.
- U.S. Patent No. 4,889,663 issued December 26, 1989 to Pfenninger. It discloses the use of diafiltration to separate waste water into a disposable organic free aqueous permeate effluent portion and an aqueous retentate portion that is concentrated with organic compounds.
- U.S. Patent No. 4,818,409 issued April 4, 1989 to Puetter et al.
- U.S. Patent No. 4,765,905 issued August 23, 1988 to Kitamura et al. discloses a method for recovering acids from an aqueous solution of a mixture of the acids and metal salts by dialysis using a fluorinated anion exchange membrane io ⁇ e ⁇ f et uu ⁇ uiyiiiei having repeating units of a given formula.
- Japanese Patent No. J5 8058-112 issued April 6, 1983 to Tokuyama Soda discloses the use of a multistage dialysis to reclaim or purify various inorganic and organic acids from their metallic salts.
- J6 0132-604-A issued July 15, 1985 to Toray Engineering discloses a method for concentrating and recovering valuable organic compounds also containing inorganic salt by desalting using membrane-separation treatment under an operating pressure above the osmotic pressure of the aqueous solution. Dilution water is added during the treatment to keep the settled level of the starting tank.
- This patent thus discloses a salt removal process. Such processes represent older, more costly, less efficient ways of converting aminocarboxylic acids salts to aminocarboxylic acids.
- the present invention is directed to an improved method of converting aminocarboxylic acid salts.
- a method for producing an aqueous solution of an aminocarboxylic acid from an aqueous solution of an alkali metal salt of the aminocarboxylic acid is disclosed.
- the first step of the method is to adjust the pH of the aqueous solution of the alkali metal salt of the aminocarboxylic acid to between 1.0 and 3.0. This is done by adding a monovalent inorganic acid to the aqueous solution of the alkali metal salt of the aminocarboxylic acid to form an aqueous feed solution containing protonated aminocarboxylic acid and an inorganic alkali salt having an inorganic anion and an alkali metal cation.
- the second step of the method is to pass the aqueous feed solution through at least one membrane using a diafiltration process to separate the aqueous feed solution into an aqueous permeate solution containing the alkali metal cation and an aqueous retentate solution containing the aminocarboxylic acid.
- the present invention discloses an improved method for producing an aqueous solution of an aminocarboxylic acid from an aqueous solution of an alkali metal salt of the aminocarboxylic acid.
- the first step of the method is to adjust the pH of the aqueous solution of the alkali metal salt of the aminocarboxylic acid to a pH less than or equal to the isoelectric point of the aminocarboxylic acid.
- this pH is preferably between 1.0 and 3.0, and more preferably for HEDTA between 1.9 and 2.3. If higher pH levels are used, the aminocarboxylic acid salt will not generally be maintained in a completely protonated acid form so that all of the sodium ions are dissociated and available for removal. Lower pH solutions can be diafiltrated but with disadvantageously more difficulty and expense to use and to maintain. Additionally, safety and environmental concerns motivate against using lower pH levels with the associated excess acid.
- the alkali metal salt used is suitably one that has replaced all available hydrogen dissociation sites with alkali metal atoms, or is optionally one that has only some such available sites replaced with alkali metal atoms . The level of replacement will not effect the process.
- the pH of the aqueous solution of the alkali metal salt of the aminocarboxylic acid is adjusted by adding a monovalent inorganic acid to the aqueous solution.
- the monovalent inorganic acid is selected from the group consisting of the hydrogen halides, and nitric acid.
- the monovalent inorganic acid is hydrogen chloride. Divalent acids such as sulfuric acid do not work well for the purposes of this invention, because the negative ions involved are too large and too highly charged to easily pass through the diafiltration membrane.
- the adjustment of the pH of the aqueous solution of the alkali metal salt of the aminocarboxylic acid results in an aqueous feed solution containing protonated aminocarboxylic acid along with an inorganic alkali salt having an inorganic anion and an alkali metal cation. It is also preferred that the aqueous feed solution have an aminocarboxylic acid alkali metal salt concentration sufficient to supply a high concentration driving force for the displaced alkali metal salts so that they are driven through the diafiltration membrane, yet insufficient to exceed the aminocarboxylic solubility limit at the membrane/solution interface.
- process efficiency is determined by the difference between the concentration of alkali metal salts in the permeate and the concentration of the aminocarboxylic acid in the permeate at any time. This difference is larger during the initial stages of the process, when the concentrations of alkali metal salts in the feed solution are larger. Since little aminocarboxylic acid is lost, its concentration is essentially constant.
- the feed concentration of aminocarboxylic acid is between 1 and 25 weight percent for aminocarboxylic acids in general, more preferably from between 6 to 20 weight percent, most preferably from between 9 to 15 weight percent.
- the preferred feed concentration is from 6 to 15 weight percent.
- feed concentration is not significant for laboratory experiments, it is more important in full scale production systems. Optimal feed concentrations balance osmotic forces against increased membrane surface area, make-up water use and other factors. Such balance is within the skill in the art. The examples hereafter reveal the above range to be desirable.
- Aqueous feed solution temperature is also an important variable.
- aqueous feed solution temperature is maintained sufficiently high to maintain the aminocarboxylic acids in solution, preferably between 10°C to 50°C, more preferably between 35 and 50°C, most preferably between 40 and 45°C.
- aminocarboxylic acid salts have good solubility in water and typically increase in solubility with increasing temperature.
- aminocarboxylic acids themselves typically have lesser solubility in water. The preferred temperatures help keep the acids in solution and, thus, help avoid membrane fouling problems.
- HEDTA acid has a 6 percent solubility at 20°C, although it exhibits 70 percent solubility at 90°C. Keeping the aqueous feed solution warm helps to keep the HEDTA acid in solution.
- the normal solubility curves of the aminocarboxylic acids used helps in collecting a very pure product by concentrating the end feed at a high temperature and then cooling it and collecting the crystallized final product. The preferred temperature ranges are based upon a variety of these factors.
- the present invention is applicable to any aminocarboxylic acid.
- the aminocarboxylic acid is selected from the group consisting of N- (hydroxyethyl)-ethylenediaminetriacetic acid, diethylenetriaminepentaacetic acid, and hydroxyethyliminodiacetic acid, dihydroxyethyl glycine, iminodiacetic acid, glycine and mixtures thereof.
- the next step of the method of the present invention is passing the aqueous feed solution through at least one membrane using a diafiltration process to separate the aqueous feed solution into an aqueous permeate solution containing the alkali metal cation and an aqueous retentate solution containing the aminocarboxylic acid.
- a diafiltration process Any appropriate diafiltration process is suitably used, as described in further detail hereinafter.
- any diafiltration membrane or membrane system is suitably used, for instance, membranes made of polyamide, polysulfone, nylon, cellulose acetate, acrylnitrile, polypropylene or polyvinylidene fluoride (PVDF) .
- the membrane is selected to achieve a rejection rate of the inorganic salt anion of at most 40 percent and a rejection rate of the aminocarboxylic acid of at least 94 percent. Most preferably, the membrane is chosen to achieve a rejection rate of the inorganic anion of at most 20 percent and a rejection rate of the aminocarboxylic acid of at least 98 percent.
- the preferred membranes are those formed of polyamide. Thus, as the following examples show, the inventors have had particular success with polyamide nanofiltration thin film composite membranes commercially available from FiinitecTM Corporation of Minnesota, a subsidiary of The Dow Chemical Company, under the trade designation FilmtecTM NF-40 and NF-20. Lower product losses are observed when using the FilmtecTM NF-40 polyamide membrane. These membranes are selected for their high rejection rate of monovalent ions.
- the membrane used is advantageously acid resistant, at least to the acidity of the aminocarboxylic acid and monovalent inorganic acid used.
- aqueous retentate solution it is desirable to recycle at least a portion of the aqueous retentate solution to the aqueous feed solution to be refiltered to achieve a higher overall rejection rate of the aminocarboxylic acid.
- Any appropriate recycling system may be used.
- aqueous retentate solution it is more preferred to cool a portion of the aqueous retentate solution, advantageously to less than 30°C to cause crystals of aminocarboxylic acid to precipitate out of the cooled portion of the aqueous retentate solution.
- These precipitated crystals are optionally filtered out of the cooled portion of the aqueous retentate solution, and the remaining aqueous retentate solution is returned to the aqueous feed solution.
- a feed tank which contains an aqueous solution of an aminocarboxylic acid alkali metal salt.
- a second feed tank holds make-up water.
- the aqueous solution of the aminocarboxylic acid alkali metal salt is drawn off and mixed with the make-up water to adjust the pH of the aqueous solution of the aminocarboxylic acid alkali metal salt to a predetermined operating pH.
- the adjusted mixture is then pumped, under pressure, through the designated membrane, resulting in an aqueous permeate solution containing the alkali metal cation and an aqueous retentate solution containing the aminocarboxylic acid.
- the aqueous retentate solution is recycled until the indicated level of desalting has occurred.
- aqueous retentate solution is cooled to precipitate crystalline aminocarboxylic acid product out of the solution.
- the crystals are then removed, and remaining aqueous retentate solution is returned to the feed tank for further processing.
- a heater is used in most examples.
- the aminocarboxylic acid salt was dissolved in the deionized water before the HC1 addition. Then enough deionized water was added to bring the total weight to 1200 grams.
- a variable speed feed pump was started and feed was recirculated at minimum back pressure that was for five minutes.
- An initial feed sample of 200 g was removed from the feed tank for analysis.
- the operating pressure as listed in each table was then set, and permeate was recycled back to the feed tank. After 5 - 10 minutes of permeate recycling to establish steady state conditions, the run was initiated by routing the permeate stream to a graduated cylinder. Initial time, temperature, pressure and flow rate were recorded. Permeate volume was recorded and composited for samples every 200 ml along with the time to collect the permeate, pressure and temperature.
- the feed was maintained at a constant volume by replacing every 100 milliliters of collected permeate with the same volume of deionized water.
- the procedure was repeated until the desired level of washing was reached. While the process can be stopped after as little as 1% removal of Na + or continued until the Na + was almost totally removed (99.9 mole percent), these examples were continued to the degree of removal indicated by the ratio of final concentration of Na + to original concentration of Na + given in the tables.
- the pump was then shut off and then feed was drained out of the system. Care was taken to drain all low spots in both feed and permeate lines.
- the membrane used in the work was a membrane which consists of a thin coating of a polyamide polymer as the active layer on top of a porous backing material, commercially available from Film Tec Corp. under the trade designation FilmtecTM NF-40.
- a sodium chloride rejection test was performed. Rejection of the salt from a dilute ( ⁇ 1 weight percent) solution was 39.3 percent at an applied pressure of 300 PSIG (pounds per square inch gauge) (2068pKa) . This was close to the nominal factory specification for this material, indicating the membrane and installation were satisfactory.
- ppm was parts by million by weight
- ppm was parts per million by weight TC was total organic carbon
- ppm was parts per million by weight
- TC was total organic Table 4 .
- the end feed from Example 3 had crystal formation after cooling to room temperature and equilibrating overnight.
- a 24.2 g sample crystals were collected from 995 g of end feed.
- the crystals analyze as 180 ppm Na + and 380 ppm Cl ⁇ by weight of dry crystal or a 99.7 percent Na + reduction with respect to the initial feed. This corresponds to 18 ppm Na + and 380 ppm Cl ⁇ in a 10 percent HEDTA acid solution.
- the end feed solution for Example 3 would result in 200 times the Na + and Cl ⁇ concentrations, according to Table 3, if it were diluted to a 10 percent HEDTA acid solution.
- the Na + to Cl ⁇ ratio indicates that all of the sodium was tied up as NaCl with the remaining residual Cl ⁇ as HCl. Therefore, there was a high probability that as diafiltration was continued there should be proportionately lower concentrations of Na + and Cl ⁇ found in the crystals.
Abstract
Description
Claims
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
BR9508915A BR9508915A (en) | 1994-09-13 | 1995-09-05 | Process for production of aminocarboxylic acids containing low residual salt content |
AU34630/95A AU3463095A (en) | 1994-09-13 | 1995-09-05 | Process to produce aminocarboxylic acids containing low residual salt |
MX9701880A MX9701880A (en) | 1994-09-13 | 1995-09-05 | Process to produce aminocarboxylic acids containing low residual salt. |
EP95931045A EP0781269A1 (en) | 1994-09-13 | 1995-09-05 | Process to produce aminocarboxylic acids containing low residual salt |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US08/305,111 US5491259A (en) | 1994-09-13 | 1994-09-13 | Process to produce aminocarboxylic acids containing low residual salt |
US08/305,111 | 1994-09-13 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1996008464A1 true WO1996008464A1 (en) | 1996-03-21 |
Family
ID=23179378
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1995/011093 WO1996008464A1 (en) | 1994-09-13 | 1995-09-05 | Process to produce aminocarboxylic acids containing low residual salt |
Country Status (7)
Country | Link |
---|---|
US (1) | US5491259A (en) |
EP (1) | EP0781269A1 (en) |
AU (1) | AU3463095A (en) |
BR (1) | BR9508915A (en) |
CA (1) | CA2198007A1 (en) |
MX (1) | MX9701880A (en) |
WO (1) | WO1996008464A1 (en) |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE19839209A1 (en) * | 1998-08-28 | 2000-03-02 | Fraunhofer Ges Forschung | Process for obtaining solid substances from solutions |
IT1311984B1 (en) * | 1999-03-26 | 2002-03-22 | Bioindustria Lab Italiano Medi | PROCEDURE FOR THE PREPARATION OF GABAPENTIN. |
NL1012975C2 (en) * | 1999-09-03 | 2001-03-06 | Stork Friesland Bv | Method for removing organics (TOC), pesticides, or other substances from a salt solution. |
DE60117620T2 (en) | 2000-11-22 | 2006-10-12 | Sandoz Ag | PREPARATION OF CEPHALOSPORIN |
JP4733031B2 (en) * | 2003-07-21 | 2011-07-27 | アクゾ ノーベル ナムローゼ フェンノートシャップ | Aqueous solution of sodium salt of HEDTA |
KR101832027B1 (en) * | 2011-11-25 | 2018-04-04 | 바이오포어 인디아 파머슈티컬스 피브이티. 엘티디. | Process for the purification of polyaminocarboxylates |
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GB2098206A (en) * | 1981-05-07 | 1982-11-17 | Toyo Soda Mfg Co Ltd | Method for separating and purifying amino acid using an amphoteric ion exchange membrane |
JPS5858112A (en) * | 1981-10-03 | 1983-04-06 | Tokuyama Soda Co Ltd | Recovery of acid |
JPS60132604A (en) * | 1983-12-19 | 1985-07-15 | Toray Eng Co Ltd | Method for concentrating and recovering organic valuables |
EP0184381A1 (en) * | 1984-12-07 | 1986-06-11 | The Dow Chemical Company | Electrochemical process and cell |
EP0274387A2 (en) * | 1987-01-08 | 1988-07-13 | Filmtec Corporation | Alkali resistant hyperfiltration membrane |
EP0300451A1 (en) * | 1987-07-20 | 1989-01-25 | Ajinomoto Co., Inc. | Method for separation of electrolytes, and method for ion exchange of electrolytes with counter-ions |
FR2619380A1 (en) * | 1987-08-10 | 1989-02-17 | Ajinomoto Kk | PROCESS FOR THE RECOVERY OF L-AMINO ACIDS FROM FERMENTATION LIQUORS CONTAINING THEM |
US4818409A (en) * | 1985-04-20 | 1989-04-04 | Basf Aktiengesellschaft | Obtaining aqueous solutions of organic acids or bases from aqueous solutions of their salts |
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FR2283167A1 (en) * | 1974-06-04 | 1976-03-26 | Rhone Poulenc Ind | USE IN SELECTIVE DIALYSIS OF MEMBRANES BASED ON ION EXCHANGER POLYMERS AND A BINDER |
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US4677065A (en) * | 1986-03-24 | 1987-06-30 | Aktieselskabet De Danske Sukkerfabrikker | Production of improved protein isolate derived from seeds of a grain legume |
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ES2020344B3 (en) * | 1987-04-16 | 1991-08-01 | Ciba-Geigy Ag | PROCEDURE FOR OBTAINING CONCENTRATED AQUEOUS COLORING PREPARATIONS. |
GB2207618B (en) * | 1987-08-05 | 1991-05-15 | Ciba Geigy Ag | Process for treating aqueous fluids containing organic compounds and salts of polyvalent inorganic acids |
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1994
- 1994-09-13 US US08/305,111 patent/US5491259A/en not_active Expired - Lifetime
-
1995
- 1995-09-05 CA CA002198007A patent/CA2198007A1/en not_active Abandoned
- 1995-09-05 MX MX9701880A patent/MX9701880A/en not_active IP Right Cessation
- 1995-09-05 WO PCT/US1995/011093 patent/WO1996008464A1/en not_active Application Discontinuation
- 1995-09-05 AU AU34630/95A patent/AU3463095A/en not_active Abandoned
- 1995-09-05 EP EP95931045A patent/EP0781269A1/en not_active Ceased
- 1995-09-05 BR BR9508915A patent/BR9508915A/en not_active Application Discontinuation
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Also Published As
Publication number | Publication date |
---|---|
CA2198007A1 (en) | 1996-03-21 |
EP0781269A1 (en) | 1997-07-02 |
BR9508915A (en) | 1998-07-14 |
MX9701880A (en) | 1997-06-28 |
US5491259A (en) | 1996-02-13 |
AU3463095A (en) | 1996-03-29 |
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