September 1947
INDUSTRIAL AND ENGINEERING CHEMISTRY
,Sonit*use has been niatic of the sulfonainide i,vsins in a treatiiig Iluriiin for tcrtile fibers to impi,ove dyping qualitic-, abrasinii. : i i i t l w t e r rcsistancc of thc woven cloth.
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.ACKSOWLEDG\IEST
l i t ) authors ivish t o cspress their appreciation to the Research Ih*liai'tnicnt,Organic Chrmicals Division, and the Plastics Divi-ion of Ilon.;anto Clicmical Company for fiirnishing rc>r cinta.
LITER-ATURE CITEI)
1087
( ; 3 ) G a i d i i e i , . tl. .\.. Ihlri., 1 . 5 f j 4 , f i M (4) Garduet.. Ti. .\., aiid Iii!,kpatri
Co., I b i d . , 2,187,199 (.Tau. 16. , I:sI;. ( ' H L I I . , 19, !I72 ( 3 ) Gartliier. 11. A , . ani1 Sn-ai,d, G. G , IN?, (19271, (6) AIrlIa*ter. L.,J . A m . Chcni. .Sot., 56,204 ~19.34). 1 , ( 7 ) l l n n - e l . C. S..Elliott, ,J, R..Boettner. F. E., :IIIII ~ ~ u - 1 ~H., Ihid.. 6 8 , 1681 (19461. (Sj Peter-., F.T.(to du Pout C o . ) , U. S. Pat.ent 2.:3:17,h:i-i (1)ec. 2 8 , 1943,. (9) Itichter, I f . J. ( t o du P o n t C o . ) ,I b i d . . 2,342.370 (Fel,. 23, 10448. (10) Schmidt,. .Ilbrecht, Ihid., 758.335 (April 26, 1904). (11) Yaala. G . T. (to du Pont To.), I b i d . , 2,270,487 ( l l n r i t : 1 7 , 1912). ' 1 2 ) Walter. G., Trans. Fnradau Soc.. 32, 400 (193tii. :it
- T L D befure the Division of P a i n t , Varnish, and P l a h t i c s C lir!lii.rr? the I l O t h \IeP-ing o i t h e AVF;F.IC.AS CHEMICAL F o c , r i . n . Cliii~raeri.Ill
Z-Malic Acid as By-product in Apple Sirup Manufactured by Ion Exchange 33 E. BUCK1 \_UD H. H . VOTTERS? Eacrsterri Keginrirrl K r s e n r c h L a b o r n t o r , . I
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5'. D r p c i r t m m t oj 4 p r i c i i l t u r r . Philmtlelphicz 18,
*l'lie I-malic acid which i- atl~orbecl o n a n anion exvlianger in the preparation of a I~laiitlapple sirup can be rc('o\ered from the emuelit frorri the sodium carbonate regeneration of the exchanger. Only a slight modification i- tirce-barr in the regular regenerati-e prorrdure to re-
I'IiEI*IOUS paper ( 4 ) described a procedure for the removal of malic acid irom apple juice b>- adsorption on a n anion 1bvclranger used in the manufacture of apple sirup. Deacidift(.;irion results in a lower requirement of lime for thr prwipitation r ! f pcctin than in t h r original sirup proceeq (I?), leaves less calI,iiiiii malate in thc juice, and produces a blander sirup. The 1)rt-cnt paper describes a proccadure n-hereby the malic acid call L , obtaincd :I; a by-product from the deacidification step in the tiiaiiui'acturc of this type of applr sirup. llalic acid can be ti-rci as a food acidulant, and the actire acid might also h a r e .I)rcial application in chemistry, i71iei.e a n optically active comIitiund is desired. It is generally recognized that l-malic acid (levorotatory) is the) I)i,incipalorganic a d in apples, although the presence of citric acid l i x ; Iwen reported (2, 7 , 1 4 ) . T h e absence of other acid simplifies flie procedure, since it, is not necessary to separate acids. S o 6,vicIence of a n acid other than I-malic n-as found in t,he appli, .iuicc used in the experiments reported herein. Charley et al. i . 7 ' prepared malic acid as a by-product in the manufacture of xl)plc treacle. Tlicy iieutralized the excess acidity of the juice \\ i r h calcium carbonate and, on concentrating, obtained a pret4pirate of neutral calcium malate. Juice of high acidity (0.7%) \$:Iused in their 11-ork. T h e present authors m r e unable to tlriplicate their results with juices of a lower acidity (0.4C;) ci~iiimonlg found in America. Active I-malic acid has also t i t v n prepared from maple sugar sand (IS) and mountain ash lwrries (BO). Anion exchangers have been used in the recovery of tartaric acmid from grape wastes ( I O ) . I n the present work the anion cArclinnger is used as a n acid adsorber, inasmuch as the main r)iirpose is the reduction of the acidity of apple juice. Regen1
Present address, Quartermaster Food S Container Institute, Chicago.
111. 2
Present address, H. .J. Heinz Cuiiipniii., Pittshurgil, Ps.
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co7er what \rould otherMise be waste material. 'Ihe .ic.id is obtained in the regenerant effluent as the solu1)le sodium w l t . precipitated as the nornial calrium salt. and conierted to the free acid b> double decomposition with wlfuric arid.
cratioii is acconiplishrd Kith sodium carbonate solution, ai111 r!le acid is recovered in the regenerant effluent. a s the solublo soiliuin salt and is prccipitatrd from the effluent as the insoluhlf. c:ilt.iuiil salt. Free malic acid is very difficult to crystallize. Tlir >+1)1)1(\ sirup manufacturer would probably prefer i o sell the c:il(,iunl malate to cheinical manufacturers, v h o in turn n-ould p r ~ ~ p : i l ~ c ~ the free acid, either in crystalline form or as a concc,iiri,rttcd solution. It was also thought that the distillery waste from applc bi,rincLy manufacture might be utilized as another source of inalic~acid. IIo\~-cver,analysis has shown that such wastes cont:tin litr I(,, it' any, malic acid. Malic acid is partially or completcly ticat i ~ 1 i y 1 ~ 1 during the fermentation procew, probably being convt>rfi.clI I I lactic acid (8). DETERIIIIYATIOS OF MALIC ACID
Since malic \vas the only acid in thc apple juice u < c d iii I t i t , - ( .studies and since it existed almost entirely in the uiicoiiitjinc~~l condition ( 2 ) , determination of the titratable acidity of applt. juice gave its malic acid content. The juice was titratccl w i t h standard alkali t o a pH value of 8.1 ( 3 ) rather than to a plicnolphthalein end point. T h c lat.ter is difficult to read 11cc:tuse of the color of the juice and because of the apprccia1)le darlxniiig which occurs as the acid is neutralized. The method generally employed for determination of sodium malate in the regenerant effluent is based on the fact that nialic acid JTith a uranyl salt forms a coniplex n i t h greatly incrcastd rotatory power ( 6 , 0 , 2 2 ) . X a n y modifications have twrri described in the literature. The one described here is a siniplifiod A.O..l.C. procedure (I),since no other optical1:j active .;uhstaiic,iare present in appreeiahle quantities. dnal! thpre is no -ug:ii. i n tlic, i'clgc>neranteffluent.
1088
INDUSTRIAL AND ENGINEERING CHEMISTRY
'4 VOLUMES'
cJshaustcd. l ~ ~ s c ~ h a n gbeds i ~ r of 1- and 4-inch diameters were usod. The capacity of the anion exchanger used is atiuu1 1.5 volumes of juice, of approximately 0.4c; malic. acid contrnt, per volume of exchanger: thi. rtxprescxrits a n adsorption of ahout 750 niillicquivtilents, or approximately 50 grama, of malic. acid pc'r litrr of rsrhanger. Variations in capacait. t'riini 650 t o 850 milliequivalcnts pcxr littr 1ia1.c' I ~ I Y * I I notcd for tho .same rschangc,r \vi1 ti diffi>rent juiccj.. Thtt anion exchanger used \vas De-.iciditc (Thv .I'carmut it C'oniprtny), although other eschangci~swill \riirk equally ~rvll.
SMALL BOXES-0.5 VOLUME LARGE
BOXES- 1.0 VOLUME
F - l VOLUME
FRESH
5%
No2C03
CYCL
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Vol. 39, No. 9
REJIOV.4L FRO31 .\UIOU EXCIIANGER
After the c ~ s h a u ~ t i o01' i i rhrl t,schangcr, t h r s bccl is backwashed Kith water t o remove rwidual ,juice and thrn regenerated with sodium carboiiI I I 1 ate sulution in preparation for the nest ryvIc2. The acid is removed from the eschanger in thi, regenerant ttfFIuent as the soluble sodium salt. The oIiginal regrbnerant consists of 4 volumes of 4 5 sodium rarbor~atesolution and is passed I J dowifioiv t l i i ~ ~ ) u gthe h c.schanger hrd at a ratr of 2 gallon< Iii'r miiiuti, ptr q u a r e foot of crop* -4 tiunal n i ' c ~ + of tlic 111vl. The volumc of rijgencrarit uscd is rxpriwcd in tc,rnis of the voluriiv nE tlii. lied tlict rc'gtwcrani p a s s r ~through t h(. txvl, Inoat of tho malait' is eluted in the firqt portion (it' tlica t$fluent as shoirn in Figurr 1 , i n n-hirh thc pi'r(~i~ntagt's indicatc the mulatcy conwnti~atioiiin the ttFluent fractions. Tlic fiwt 0.5 -5 I I I 1 volunii~of cifflucynt (fraction &A) is d i s c a r d d , e i n w it it largely tlicz \rsti,r displaced from the b 1 ~ and 1 cwntain. littlt., if any, malatr,. Tho ~ ~ ~ g i ~ n ec~fflut~nt l ~ a n t is recycled i r i order t ( t tiuilcl u p t l i c malate concentration to about 5c;. at Trhich point satisfztct ory prwipitation of calcium malate can hr obtained. A flow diaFigure 1. BIethod of Hecjcling Regenerant for Recoiery of RIalic Acid gram for rocycling the regenerant, is illustratcd Upper percentage indicates malate content in Figuri, I . After discarding frartion .I, four I-volunw fi~artions of effluent are colThe procedure is briefly as follo\vv;j: Pipet a 25-ml. samplc Icetttd ti.oiii e:wh cy[-le. K a t c r i? then pa. into a 100-ml. volumetric flask; make it, just alkaline to a phenolbcd t o rinse, out the escess alkali, and the b pht,halein end point with 1 A; sulfuric acid or 1 S sodium hvfor th(. tleacidification of apple juice in the nest cycle. The droxide; add 2 ml. glacial acetic acid and make to volunle: transfer a 20-ml. aliquot t o a 25-m1. volumetric flask containing regenerant effluent fractions from cycle I, after fortification with approximately 3.0 grams of uranyl acetate (finely ground) : morc sodium carbonate, are then' pa d through the exchanger shake vigorously at intervals for 3 hours; make t o volume with bed in order as the regenerant for ryclc 2. This procedure is saturated uranyl acetate solution and filter; polarize in a 200repeatrti until thc malate concentration in fraction B has reached mm. t,ubewith sodiumlight. Calculation: degreesangular rotation t h r desired 1-alue, and B is tht7Ii ri-movcd for recovery. The X 0.519 = grams malic acid per 100 ml. of original solution. remainder of the fractions are used as the regenerant for the next cycle with the addition of one volumci of frpsh 5% sodium carThe accurary of t h r method variei, b u t the results a l e conbonate solution as shown in the diagram for cycle 4. From this sidered sufficiently reliable to estimate the malate content of tho point on, fraction B, irhich was fraction C in the preceding cycle, regenerant effluent. Foi determining the purity of the preis withdrawn for precipitation. cipitated calcium malate, the authors have relied on calcium AftcTr cycle 1, fraction C is not fortified with more sodium and ash determinations. Comparison of the two methods of carbonate, since it already contains an escess, and passagc analysis on samples of calcium malate shows t h a t the polarithrough the eschanger in the next cycle reduces this escess so metric method gives results which may vary as much as *5'; that thcre is less carbonate t o remove in the precipitation proof thoqe obtained by calcium and ash determinations. cedurcx. The slight reduction of malate content from fraction C, cyc.1~:1,t o fraction B, cycle 5 , is probably due t o dilution by ADSORITION ON 4YION EXCHANGER water i n tho exchanger which more than offsets the gain derived General methods for tlp use of ion exchangers (15, 15, 16, f9) from a nucceeding elution. The rinse n-ater used after fraction and their particular application to the deacidification of apple E has been collected may contain small amounts of malate. juice have been described in detail elsen here (4). The screened and the first portion of this rinse water may be used for preparing (200 mesh) juice is passed do\
