Aug. 25, 1953 D. W. colleR 2,650,248 CONCENTRATION OF AQUEOUS. ACONITIC ACID SOLUTIONS Filed March 5, 1950 s N N is 8 uunOO uo. 901x3 C s S. s JunoC) 5d 5 UO43Dux3 2 8 S 2 1) G RO () o has O. e foL o uunOO UooDux INVENTOR. DONALD W, COLLER SUD. eÖDOS BY hby Gaula 9. UDueuebe ATTORNEY. Patented Aug. 25, 1953 2,650,248 UNITED STATES PATENT office 2,650,248 CONCENTRATION OF ACUEOUS ACONTIC ACD SOLUTIONS Donald W. Collier, Philadelphia, Pa., assignor to The Sharples Corporation, a corporation of Delaware Application March 15, 1950, serial No. 149,864 6 Claims. (CI. 260-537) 2 This invention relates to a process and appara this method the blackstrap molasses of about 85 tus for the recovery of substances from relative Brix is suitably diluted with Water to about 50 ly dilute Solutions thereof. More Specifically, the Brix and is heated to about 50° C. Blackstrap invention relates to the recovery of aconitic acid mola SSes is the by-product of raW Sugar manu from relatively dilute aqueous Solutions contain- 5 facture. It is a heavy Wiscous liquid Separated ing impurities and foreign substances by contact- from the final low grade maSSecuite from which ing the aqueous solution with an organic Solvent no further Sugar can be crystallized by the usual to form two phases in which the aconitic acid is methods: The density of blackstrap molasses concentrated in the non-aqueous: phase, there- ranges from 85 to 92 Brix, containing total after adding hydrocarbon type solvent to the non-0 solids by drying of 77 to 84%. The SucroSeco aqueous phase which is miscible therewith and tent varies by Weight between 25 and 40% and the then contacting the mixed non-aqueous phase reducing Sugars from 30 to 12% With total Sugars with a small volume of water to form tWO phases about 50%. It contains anywhere from 0.5 to 5% in which the aconitic acid is concentrated in the on Brix of aconitic acid, and Small amounts of aqueous phase. other organic acids such as succinic acid and ox According to my invention I provide a system alic acid, and also substantial amounts of mineral and method for continuously recovering a sub- salts such as the chlorides, Sulfates and phOS stance, such as aconitic acid, without substantial phates of potassium, calcium, magnesium and loss of the organic solvents used by providing for Sodium. The molasses liquor is treated in a three the cyclic recovery of the solvents in my system 20 stage counter-current manner, for example, with and contacting the stream of aqueous Solution an anion exchange resin containing adsorbed Sul with a counter-current stream of a Substantially furic acid. This resin may be Ionac A-300, sold water-immiscible organic solvent in a plurality by American Cyanamid Company, New York, of stages. The concentration of the Substance, N.Y., which is an aliphatic amine phenol-formal Such as a conitic acid, is increased in a double ex- 25 dehyde resin. As an illustration, if the molasses traction system by virtue of the change in its dis- contains about 2.4% aconitic acid on Brix, the tribution tendency between Water and an organic dry base regenerated weight of the resin used is phase brought about by the addition of the hy- conveniently about 7% of the weight of the drocarbon type solvent to the organic phase con- diluted molasses. Line is added to the stage in taining the aconitic acid so that the final aqueous 30 which the anion exchanger first contacts the Solution issuing fronny System is of a greater molasses to adjust the pH Within a pH range concentration as compared with the untreated of about 4 to about 6 and preferably to about 5.0, aqueous solution fed to the system. the point, at Which the Selectivity of the ex Aconitic acid is found in substantial amounts changer for aconitic acid Over mineral acids is at in blackstrap molasses and Sorgo juices in 35 a maximum. Reference is made to co-pending amounts as high as 5% by Weight of solids. The application Serial No. 150,548, filed March 18, aconitic acid can be separated from the molasses 1950, by Hugh G. Bryce wherein such procedure by an anion-exchange material which is then is described and claimed. Each stage comprises treated to produce an aqueous solution of aconitic a steel treating tank with agitator which can be acid containing other impurities such as mineral 40 heated with live steam to maintain the tempera acids, organic substances, and coloring matters ture of about 50 C. Separation of molasses and derived from the molasses. According to my in anion, exchange resin between stages is accorn vention such solution of aconitic acid is extracted plished by the use of vibrating screens. The With a suitable organic Solvent, Such as iso- molasses Solution leaving the third stage is passed phorone, and the extracted solution is further 45 through a centrifuge to remove the calcium Sull treated to isolate substantially pure aconitic acid. fate which is formed during the treat. This Further features and advantages of my inven- calcium sulfate is dropped into a settling tank tion will be evident from the following illustra- filled with Water, to dissolve the adhering tive embodiment of my invention in connection 50 mola SSes from the Solid. The SWeet Water may with the accompanying drawing. A solution con be then used in diluting the treated molasses fur taining aconitic acid to be treated in accordance ther to prepare it for fermentation, if desired, with my invention may, for example, be produced While the solids are discarded through a valve in accordance. With the method disclosed in my in the botton of the tank, which is operated copending application, Serial No. 149,863, filed periodically. March 15, 1950. According to an embodiment of The exchange resin, having passed through the 2,650,248 3 4. three stages, is washed on a vibrating screen to and benzene separated in settling tank A is fed remove the adhering molasses and is dropped into by line 9 and mixed in line 9 with a similar the regeneration tank. The sweet water result mixture of benzene and isophorone and finally ing from the Wash is used in diluting the raW mixed in pump 21 and line 22 with the isopho molasses. The pH in the regeneration tank is role stream from column . The amount of ben maintained at about 0.9 and not exceeding 2.0, Zene used is regulated to be about 1.5 times the by continuous addition of H2SO4. The mixture volume of isophorone fiowing through line 4t, of resin and regenerant solution which now con to a centrifuge 23. The addition of benzene re tains most of the aconitic acid that was on the Sults in the formation of a small amount of a resin is separated on a vibrating screen and the O Second phase of tarry liquid which is conveyed exchange resin is Washed counter-currently in in the stream of isophorone and benzene and fed three stages on a vibrating screen to remove the to centrifuge 23. This separation may be a C remainder of the aconitic acid and some of the complished in a settling tank instead of a centri Sulfuric from the resin. The resin is now ready fuge. The tarry phase is separated by the cen to be reused in the counter-current adsorption trifuge and is fed by line 24 to a settling tank B train. The wash-water is used as make-up water through which a water stream flows supplied by in the regeneration tank. r line 8. The regenerant solution separated from the The aqueous phase from tank B, containing exchanger on a vibrating screen, is then sub Some Water-soluble impurities and a Small jected to purification and recovery in accordance 20 amount of aconitic acid is fed to line 25 to join with the procedure of the present invention. the stream in line. 2 fed from the storage tank Referring to the drawing, the raw aqueous so f). As the tarry phase fed to settling tank B lution containing Say about 2.3% aconitic acid contacts the water therein it solidifies and is and impurities, as produced for example in ac- - discharged periodically from the bottom of the cordance with the method previously described, 25 Settling tank B and is discarded. ... ' is stored in a storage tank 0 from which it is The main stream of clarified isophorone and fed at a controlled rate by pump and line 2 benzene coming from the centrifuge 23 is fed to the top of an extraction column , preferably by line 26 and pump 27 to the bottom of extrac of the type which is internally agitated and pro tion column 2 which is preferably a five plate vided with say ten plates. A stream of iso 30 internally agitated column. Water is fed to the phorone is fed by line 56 to the bottom of the top of column 2 by line 8' in counter-current extraction column f in counter-current flow, flow at a volume rate 42 of that of the organic preferably at a rate 0.3 that of the aqueous feed stream. The presence of benzene in the isopho rate. This treatment strips aconitic acid and rone now causes the aconitic acid to go back in Some inpurities from the aqueous solution, 35 to Solution in the Water and as a result of the leaving behind the stripped residual aqueous SO faWOrable distribution COnStants in both extracts lution containing some sulfuric acid, a small tions, the concentration of the aconitic acid is amount of isophorone and other impurities.