Distribution of Hydroxy Succinic Acid Between Water and Organic Solutions of Aliphatic Tertiary Amines

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1 Journal of Scientific & Indu strial Research Vo l 6 1 April 22, pp istribution of Hydroxy Succinic Acid Between Water and Organic Solutions of Aliphatic Tertiary Amines Ismail Inci Universi ty of istanbul Engineering Faculty, Chemi cal Engi neering epartment, 3485, istanbul, Turkcy Recei ved : 12 Novamber 2 I; accepted :8 January 22 The extracti on of hydroxy succinic acid from an aqueous solutions into solu tions of tri-ii -octylamine and Alamine 336 in single so lvents are hexane, cyclohexane, isooctane toluene and methyli sobutyl ketone (MIBK ) is investigated Formation of acid amine compl exes is a dominating factor in the system under consideration iluents are chosen fro m different chemical classes - po lar and nonpolar- so as to examine the effect of diluents compl ex interacti ons The distribution coefficients and loadi ng factors are calcu lated and interpreted from ex perimental results - Introduction Aliphatic terti ary ammes di ssolved m an organic solvent are powerful extractants for carboxylic aci ds 1-7 The amine binds the ac id in the organic ph ase thourgh reversible complexation Often, water takes part in complex formation, thus having a strong influence on the liquid-liquid equilibrium Several workers have in vesti gated the exraction of carboxylic ac id by amines dissolved in organtc so I vents It has been found that diluents, especially those with functional groups, can affect the extracti on behaviour of amine significantl y The stoichiometry of solute:amine complex, loadi ng of amine as well as the third phase formati on are influenced by the diluent The effect of diluent can be understood in terms of ability to so lvate to organic phase species Therefore, it is necessary to di stinguish between general solvati on from electrostatic, di spersion or other forces and specific so lvation due to hydrogen bonding I' The extraction process can be described by the reactions: H2A+ R,N = H2AR, N, H2A + 2 R1N = H2AR, N2 The resulting ac id :amine supposed to be stabili ied due b on d mg Wit I 1 th e d'l l uent 14 " IS compl exes are to the hydrogen The structure of acid:amine complexes in diluents were determined by Barrow and Yerger 16 They proposed that the first ac id interacts directly with the amine to form an ion pair and the OH of the carboxyl of the second acid forms a hydrogen bonding with the conjugated CO of the carboxylate of the first acid to form a complex 161\Figure I ) O,\ / C-CH3 /O-----H-O CH -C" 3 '\', '\ - + O H NR3 Figure I - The structure of acid-amine complex In thi s work, experimental res ults for liquidliquid equilibrium in vo lved in the reacti ve extraction of hydroxy succinic ac id with tri-il-octylamine and Alamine 336 di ssolved in single so lvents hexane, cyclohexane, isooctane, toluene, and methyl isobutyl ketone (MIBK) at 25 C are presented Theoretical An equilibrium description of acid-amine system can be written by a set of reacti ons of p ac id A, molecules and q amine B, molecules to form vari ous (p,q) complexes with corresponding equilibrium constants, K pqlfue

29 J SCIIN RES VOL 61 APRIL 22 pa +qb = A pb'l' ( 1) " (2) where the spec ie;; activities are denoted by brackets and the organic phase species are denoted by bar From application point of view the

2 29 J SCIIN RES VOL 61 APRIL 22 pa +qb = A pb'l' ( 1) " (2) where the spec ie;; activities are denoted by brackets and the organic phase species are denoted by bar From application point of view the activities of the organic phase species are assumed to be proportional to the concentrations of the species, with the constants of the proportionality considered in the equilibrium constant The apparent equilibrium constant for the overall reaction can be written as: " (3) where species concentrations are denoted by square brackets and are expressed in molar terms The loading of the extractant, Z is defined as the total conce ntration of acid in th e organic phase, divided by the total concentration of amine in organic phase l 8 With appropriate materi a l balance, Z is determined for a g iven set of stoichi ometries as : PI-I ll Z = CAII}g = LPKptf!A! B CIJrIl{ C BTo/ " (4) istribution coeffi c ients fo r hydroxy SUCCIl1IC acid, extracted from water into organi c phase were determined as, [Acid concentration in orgallic phase ] = -i :::'-----'-~ [Acid concentration in aqueous phase ] Experimental Procedure " (5) Tri-Il-octylamine, hydroxy SUCCIl1 IC acid, and solvents were purchased from Merck Company Alamine 336, a commercial product (Henkel Co) W,L used as mixture of straight-chain tertiary amines with seven to nine carbon atoms per chain containing 275 mollkg of active amines (M = 363, 3 g/mol ) Ali chemicals were used as such Hydroxy succinic acid was dissolved in water to prepare the solutions with initial cone of acid 1 per cent w/w The initial organic phases were prepared by the dissolution tri-ii-octylamine and alamine 336 in the diluents to produce solutions with approximately constant conc (1,8 molll, 1,4 molll, 1, 1 molll,,7 mol/l, 4 molll reslpecti vel y) For distribution experiments equal volumes of an aqueous hydroxy succinic acid solution and an organic solution of amine were stirred in glass flasks in a shaker bath at 25 C for 2 h Pre liminary tests demonstrated that there was sufficient time for equ ilibration Thereafter the mixture was kept in a bath for another 6-8 h to complete separation The concentration of the acid in the aqueous phase was determined by titration with aqueous sodium hydroxide (relative uncertainity: I per cent)1 9 Acid analysis was checked against a material balance In most cases the deviation between the amount of acid analyed and the amount of ac id known by preparing the solutions by weighing did not exceed 3 per cent The solubilities of amine salts and diluents in the aqueous phase were negli gible in the range of variables investi gated Results and iscussion Table I and 2 present results of the experimental investi gati on The concentrati ons of amines in solvents were between 4 molll and 18 molll The hydroxy succinic acid concentration in the initial aqlleous phase was 1 mass per cent The equilibrium data on th e d istribution of hydroxy succini c acid between water and aliphatic amines (tri-il-octylamine and alamine 336) di ssolved in hexane, cyclohexane, isooctane, toluene, methyl isobtyl ketone are presented in Table I and Table 2 Figure 2 demonstrates the influence of the organic solvent on hydroxy succini c ac id di stirbution bet we e ~ water and tri-il-octylamine It can be seen that th e extraction powe r of tri-n-octylamine - diluent mi xture changes with increasin g initial concentrati on of tri-n-octylamine in th e organic phase According to Tabl e I and F igure 2, for tri-noctylamine extraction the order was as fo llows: MIB K> Tol uene> Hex ane>cyclohexane> Isooctane This fact can be explained by the formation of two or more acid: amine complexes, which are effected by the diluents in different ways i

3 INC I: ISTRIBUTIO OF HYROXY SUCCINIC AC I Table 1- Experimental result s of the extraction of hydroxy succi ni c aci d wi th tri-il-octylamine in dilut ing solvcnts iluent Hexane Isooctane Cyclohexanc Toluene MIBK C TOA (mo l l L ) A U~O lao 11 7 OA8 61 OA '57 58 OA OA AO IA I Solvation of the complex by the diluent t S a critical factor In the ex tract ion of acid The interaction s between the complex and di luent can be divided into general solvati on and specifi c interactions of the diluent with the complex Inert diluents - hexane, c),clohexane isooctane - give a very low distribution of the acid into the sol vent phase Alkanes being nonpolar provide very low solvation of the polar complexes Aromatic dilu en t (toluene) give higher distribution which has been rat ionalied as solvation due to interacti on of the aromatic fl - electron with complex MJBK is palm and can promote extraction by plovid ilig a good so lvating media foi the ion pail Table 2 - Experimental result s of thc extraction of hydroxy succinic acid with alaminc 336 in diluti ng solvents iluen t Hexane Isooctane CyclohexJne To lucne MIBK C A31!, (moll L ) OA5 OA ::< <) OAI In Figure 3 the effect of tri-f/-octylamine concentrati on on load ing is shown The loading curve is a plot of Z vs <Im ine concentration Overloading (load ing> I) indicates that complexes with morc than one acid per amine have bee n fo rmed With MJBK, overl oading can be observed at low tri-f/ octylamine concentration, (Figure ~) System) that incl ude the di luent specifically in the comple ' stoichiometr show decrease loading with increa:e in amine concentration With all of the solvents al tri-ll-octylailline, extlaction load ing decreases thereby ind icating that complexes include the diluent spec ifically (Fiellre 3) ystem_ that exhibit aggregation fort1idtion of complexes with

4 292 J SCI INO RES VOL 61 APRIL 22 large numbers of acid and amine molecules, exhibit an abrupt increase in loading, Toluene, isooctane, hexane at tri-n-octylamine extraction (Figure 3) exhibit abrupt increase at 4-14 molll amine concentration, thereby indicating that complexes include large number of acid and amine molecul es, For systems with only one amine per complex, there is no effect of total amine concentration on the loading, If there is more than one amine per complex loading increase with increase in amine concentration, 2,5r X-H ella n e --C yc t oh e l(an e According to Table 2 and Figure 4, for Alamine 336 extraction the following orders were found: MIBK > Toluene> Hexane> Cyclohexane > Isooctane, ue to high polarity of MIBK and its capability to act as a hydrogen bond acceptor, hydroxy succinic acid shows a considerable sol ubi lity in that solvent in the presence of alamine 336 (same as with tri-noctylamine), In Figure S, the effect of Alamine 336 concentration on loading is shown, With MIBK overloading can be observed at low Alamine 336 concentrations (same as with tri-il-octylamine), 12 ~ Isooclan e ~ Toluene ~ M1BK o,a,5,2,4,6,8 1,2 14 1,6 18 Concentrat io n of tr i- n -oc tylam i ne (mo I/L) Figure 2 - Vari ation of distributi on coefficients with concentration of tri-n-oclylallline in different diluting solvents Q4 Q2 - x-hexane -+-Cyclohexane ~ Isooctan e -+-Toluene -<>--M 8K 7 Q2 Q ,4 1,6 III Concentration 1 tri-o-octylarrone (rnol/l) GyJctleltane -tr-isoodane 5 C -+-TdU l1e Q) : ---4-MEI< ~ 4 " c: '5 3 J:J '': u; i5 2 1 Figure 4 - Vari ation of distribution coeffi cients with concentrat ion of alallline 336 in different diluting solvents 7 -o-hexane CVclohe l ane -c-lsooctar'9 c -+- Toluene : so -o-mibk ~ c ', " ;; 3 2,5 1,5 2 Corcer1ration 1 trioo- oc!ytarrone (mol /l) 1 O,S 15 Concentration o f tri- n-octylamine (moll L) Figure 3 - Vari ati on of loading factors with concentrati on of tri-ll-octylallline in diftcrent diluting solvents Fi gu re 5 - Vari ati on of loading fa clors with co ncentrati on of alallline 336 in different diluting solvents

INCI: ISTRIB UTION OF HYROXY SUCCINIC AC I 293 Hexane and cyclohexane exhibit abrupt increase at 6-15 moul amine concentration, thereby indicating that complexes include large number of acid and

5 INCI: ISTRIB UTION OF HYROXY SUCCINIC AC I 293 Hexane and cyclohexane exhibit abrupt increase at 6-15 moul amine concentration, thereby indicating that complexes include large number of acid and amine molcules With cyclohexane loading increases, thereby indicating that complexes include more than one amine per complex and with other solvents loading decreases, thereby indicating that complexes include the diluent specifically References Yang S T, White S A & Hsu S T, Extraction of carboxylic acids with tertiary and quarternary amines, Ind Eng Chem Res, 3 (1991) Althouse J W & Tavlarides L L Analysis of organic extractant systems for aceti c acid removal for calcium magnesium acetate production, Ind Eng Chem Res, 31 ( 1992) Tamada J A & King C J, Extraction of carboxyli c acids with amine extractants 2: chemi cal interactions and interpretation of data In d Eng Chem Res 29 ( 199) Tamada J A Kertes A S & King C J Extract ion of carboxyli c acids with amine extractants I: equilibria and law of mass action modelling Ind Eng Chelll Res, 29 (199) Hano T, Matsumoto M Uenoyama S, Ohtake T, Kawona Y & Miura, S Separati on of lacti c acid from fermented broth by solvent ex tracti on Bioseparation 3 (1993) Hartl J & Marr R, Extrac tion processes for bioproduct separation, Sep Sci Tecl1ll1 28 (1993) Malmary G H Mourgues J F Bakti J Conte T S, Achour, Smagghe F J,& Molinier J E Part ition coefficients of tartaric and hydroxy succini c ac ids between dilute aqueous soluti ons and amine extractants disso lved in various diluent s J Chelll Ell!? ata, 38 (1993) Smelov V S,& Sttrahov A V Exraction of oxali c acid by trioctyl amin, Radiokhilll, 4 (1963) Bullock J I Choi S S Goodrick A Tuck G & Woodhouse E J, Organic ph ase species in the exraction of mineral acids by meth yldi octylami ne in chloroform J Phys Cllem, 68 (1964) Vieux A S Rutagengwa N, Rulinda J B & Balikungeri A Extraction of some dicarboxylic acids by trii sooctylamine Anal Chilli Acta 68 (1974) I I Manenok G S Korobanova V I Yudina T N & Soldato v V S innuence of the nature of the solvent on extraction of certain mono- and dicarboxylic acids by amines Russ J Appl Chelll 52 (1979) Reisi nger H & Marr R, Multicomponent-liquid membrane permeation of organic acids Chelll Ellg Tecllllol 15 (1992) Bi ek V, Horacek J, Kousova A, Herberger A & Prochaka J Mathemati cal model of extraction of malic acid wi th amine Chelll Eng Sci 47 (1992) Wennersten R, The extrac tion of mali c acid from fermentation broth using a solution of terti ary amine, J Cheln Teclll1l Biotechllol 33 (1983) Yang S T, White S A & Hsu S T, Extracti on of carboxylic acids with tertiary and quarternary ami nes, Ind Eng Chem Res 3 (199 1) Yerger E A& Barrow G M, Acid-base reactions in nondi ssociating solvents: II -butyl amine and acetic acid in carbon tetrac hloride, I Alii Chelll Soc,77 ( 1955) Yerger E A & Barrow G M, Acid-base reactions in nondissociating so lvents: aceti c acid and diethylamine in carbon tetrachloride and chloroform, I Am Chem Soc, 77 (1955) Kertes A S & King C J, Extraction chemistry of fe rmentation product carboxylic acids, Biotechnol Bioellg, 28 (1986) Kirsch T, Maurer G, i stribution of oxalic acid between water and tri-n-octyl amine, Ind Eng Chem Res 3S (1996) Abbrevations and Notations A B B"'I C B1 1 MTBK p q Acid Amine = Apparent equilibrium constant Concentration of alami ne 336, (mol / L) Concentration of tri -n-octylamine (mol / L) Concentration of ac id in organi c phase at the end of ex trac ti on = Concentration of total amine in organic phase = istribution coeffi cient Hydroxy succinic acid = Equi librium constant = Mehyl isobutyl ketone Tertiary amine Number of ac id molecul es Number of amine molecules Loading fac tor

Distribution of Glycolic Acid Between Water and Different Organic Solutions

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