Powerful ChemicalProcessing Tools

DOWEXIon Exchange Resins

Dow Liquid Separations

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Table of Contents

Introduction to Ion Exchange Resins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2

Applications - Ion Exchange Resins in Chemical Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

General Considerations for Use of Ion Exchange Resins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

Resins as Solid Acid/Base Catalysts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

Metal Recovery and/or Concentration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

Solution Purification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

Chemical Conversions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Fractionations/Separations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Resins as Desiccants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Laboratory - Evaluation Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Applications and Recommended DOWEX resins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

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DOWEX Ion Exchange Resins -Powerful Chemical ProcessingToolsIon exchange resins have madeimportant inroads in the field ofchemical processing since theadvent of the synthetic organic ionexchange resins in the 1940s.DOWEX* ion exchange resins havehistorically and consistently had thehigh physical and chemical stabilitynecessary in this area of processing.The Dow Chemical Company hasdeveloped and introduced into theindustry not only these more stableproducts, but products with function-alities that allowed the companiondevelopment of new processes utiliz-ing these ion exchange related prod-ucts. Processes such as IonRetardation, Ion Exclusion, AcidRetardation, Desiccation, RadiumRemoval, Chelation, and Catalysishave been pioneered by The DowChemical Company, and Dowremains committed to the continuingsupport of this diverse industry.

Important Chemical and PhysicalNature of Ion Exchange ResinsThe Matrix. The majority of the ionexchange resins manufactured in theworld today are based on the poly-mer chemistry of styrene, crosslinkedwith divinylbenzene. The variety ofcopolymers and their functionalizedproducts, available both conceptuallyand commercially, are many. Thispolymer system has also stood thetest of time as the most stable sys-tem, physically and chemically, ofany commercially available to date.

Final resin properties may be sig-nificantly varied by changing theamount of divinylbenzene crosslink-ing agent, which alters the swollengel porosity of the finished ionexchange resin. Reaction rates arethus variable and controllable, as arethe size range of molecules that maydiffuse into and out of the resinstructure. True porosity can also bebuilt into the matrix during the orig-

inal copolymerization, forming amacroporous structure, and increas-ing the flexibility of porosity control.Suspension polymerization results inspherical particles having a broadergaussian distribution. Dow’s newertechnology adds the ability to controlthe particle size distribution to withinvery narrow limits and is availablecommercially as the DOWEXMONOSPHERE* line of ionexchange resins. Improved kinetics,reduced pressure drop, and betterresin transfer can often be achievedwith these products.

The Functional Group. Followingthe formation of the styrene/divinyl-benzene copolymer, functionalizationof the polymer structure is done toconvert the polymer into an ionexchange resin. Functionalitiesadded to the copolymer include sulfonate, quaternary amine, and tertiary amine groups. The resultingresins will be discussed below. Inaddition, special functional groupsare added for particular chemicalprocessing applications, such as thepicolylamine functionality whichforms a chelating resin useful in copper recovery.

*Trademark of The Dow Chemical Company

Introduction

Standard DOWEX Ion Exchange Beads

DOWEX MONOSPHERE Ion Exchange Beads

DOWEX Resins Significant toChemical ProcessingApplicationsStrong Acid Resins. As produced,these resins contain exchangeableH+ cations which give the resins theability to behave as insoluble, butvery reactive acids. Not only canthese resins be used to exchangethe H+ ion for the cations of a salt insolution, effectively “salt splitting” andforming the acid of the salt involvedin solution, but they can be used inplace of soluble acid in many catalyt-ic reactions. DOWEX cation resinsinclude standard gel products suchas DOWEX HCR-S, DOWEX HCR-W2, DOWEX HGR and DOWEXHGR-W2, macroporous productssuch as DOWEX M-31, uniform particle size products suchas DOWEX G-26, and driedcatalysts such as DOWEX DR 2030.

Strong Base Resins. These resins contain quaternary aminefunctionalities which have the abilityto exchange anions. When in theOH- ionic form, this class of resins iscapable of acting like very stronginsoluble bases in solution. Type Iresins incorporate quaternary methyl-amines as the functionality and arethe strongest bases of the anionresins, whereas a lower basicity(Type II) resin is formed when theamine used in the reaction isdimethylethanolamine, which resultsin improved regeneration efficiency.DOWEX anion resins include stan-dard gel products such as DOWEXSBR, DOWEX SAR, and DOWEXSBR-P, macroporous products suchas DOWEX MSA-1 and DOWEXMSA-2 and uniform particle sizeproducts such as DOWEX G-55.

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Weak Base Resins. These resinscontain tertiary amine functionalitieswhich act as acid adsorbers.DOWEX weak base resins includemacroporous products such asDOWEX M-43.

43084 is based on hydroxypropylpicolylamine, which has somewhatdifferent selectivity characteristicsresulting in enhanced iron rejectionproperties.

Polymeric Adsorbents. Polymericadsorbents are alternatives to activa-ted carbons that have high surfaceareas, low levels of extractable mate-rials and excellent physical stability.These materials are useful for decol-orizing products, product recoveryfrom waste streams and organicspurification. They have beendesigned for ease of regeneration onsite. The product family name isDOWEX OPTIPORE*.

Ion Retardation Resins. Made byreacting polyacrylic acid into the polymer structure of a Type I strongbase resin, the Ion Retardation resin,DOWEX Retardion 11A8, has theunique ability to absorb ion pairs (ofsalts) from solution, retarding theirprogress through a column, while notaffecting organic molecules, thus setting up a partition which facilitateschromatographic separation. Anotherapplication of this unique resin is toremove salt contamination from caustic solution.

Styrene-DVB Copolymers. DowStyrene-DVB copolymers are freeflowing, spherical beads made fromstyrenic polymers that have beencross linked with divinylbenzene.They are clear to colorless opaquespheres. They are hard, sphericalbeads that are often used as plasticball bearings. Applications include;lubrication, void space maintainers,grinding media, absorption and decolorization and precision fillers.

O

CH3 – N+ – CH3

CH3

O

CH3 – N+ – CH2– CH2OH

O

CH3 – N – CH3

Type I Strong Base Resins

Weak Base Resins

Type II Strong Base Resins

Weak Acid Resins. These resinscontain carboxylic acid groups whichact as base adsorbers. The familyname for the macroporous, weakacid cation exchangers is DOWEX MAC-3.

Chelating Resins. Special function-alities can be incorporated in thecopolymer to make chelating resins.Two resins that are highly selectivefor copper are DOWEX M4195 anddevelopmental chelating resin XFS43084. DOWEX M4195 is based onbispicolylamine chemistry, while XFS

O

Strong Acid Resins

SO3

CH3

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General Considerations for Useof Ion Exchange ResinsAqueous Solutions. Ion Exchangeresins are considered economicallyuseful in treatment of aqueous solu-tions when the ion to be modified isat concentrations low enough toallow a reasonable throughput beforecapacity exhaustion. Since the totalcapacity of ion exchange resinsranges to up to 2 chemical equiva-lents per liter of resin, if the accept-able throughput is 1,000 liters perliter of resin, the desired maximumtotal concentration in the feed solu-tion is 0.002 equivalents per liter.When higher concentrations areencountered, a membrane separa-tion is often used as a primary treat-ment step.

There is the additional limitationthat high concentrations of salts orions in the solution, other than theone which requires modification, willcompete with the desired reaction.This competition is part of the reasonfor the development of special resinshaving enhanced selectivity charac-teristics.

Organic Solutions. In general, ion exchange reactions can be car-ried out in any solvent system thatsupports ionization of the species tobe modified. From a practical stand-point, the more polar the solvent, thebetter the ionization, and thus, thebetter the chance for ion exchangereactions to occur. Ethanol andmethanol support ionization reason-ably well.

Solvents, which tend to be strongoxidizing agents, should be avoided.These materials can attack the resinand perhaps even cause a haz-ardous condition.

Stability Considerations.DOWEX ion exchange resins may beused as acid catalysts at tempera-tures as high as 120°C, beyondwhich resin degradation occurs. Thestrong base resin in hydroxide formmay be used as base catalysts attemperatures as high as 50°C.

The stability of the resin improves if used in a salt form rather than thehydroxide form. Resin life is alsoadversely affected by strong oxidizing agents.

Resins as Solid Acid/BaseCatalystsStrong Acid Resins are used in anumber of instances as strong acidcatalysts in place of soluble acids.Resins show similar catalytic activityto sulfuric acid in esterifications,epoxidations, hydrolyses, phenolalkylations and other acid catalyzedreactions. For example, the gasolineadditive MTBE (methyl tertiary-butylether) is formed by the catalyticreaction of methanol with isobutylenewhen passed through a bed ofDOWEX M-31 catalyst. (See Figure 1)

Occasionally, dried catalysts arenecessary for enhanced reactivityand conversion rates or where addition of water is a problem.DOWEX DR-2030 catalyst is beingeffectively used in phenol alkylation.

Strong Base Resins can replacestrong caustic in some base cat-alyzed reactions. Reactions such asester hydrolysis and condensationshave been reported.

Advantages. DOWEX ion exchangeresins have the following advantageswhen used as acid/base catalysts:

1. Separation of the catalyst fromthe reaction mass is greatly sim-plified. Filtration removes thespherical resin while extraction orneutralization with filtration arenecessary to remove a solublesulfuric acid catalyst. Indeed,resin catalysts can be used in col-umn operation, facilitating the useof a more continuous process.

2. The resin catalyst may be reusedrepeatedly. The recovered resincan be used as the catalyst inadditional batch reactions, thusthe cost of resin use per batch issignificantly reduced. Catalystcost can be equal to or below thecost of sulfuric acid per unit ofproductivity.

3. Greater selectivity of reactiondirection is often possible usingion exchange resins as catalysts.Side reactions are sometimesreduced or eliminated. In somecases, it is possible to isolatereaction intermediates not obtain-able with soluble catalysts.

4. Ion exchange resins are easier tohandle than their soluble counter-part. They do not present thehazard to personnel nor do theycause severe equipment corro-sion. Resin is easily transferredfrom one tank to another in slurryform, using air pressure or pumpsdesigned to handle slurries.

Applications - Ion Exchange Resins In Chemical Processing

y

CH2

CH3CH3

+ CH3OH

DOWEX M-31Catalyst

40˚ – 100˚C

Isobutylene + Methanol MTBE

OCH3

CH3CH3

CH3

Figure 1. Catalytic Reaction - MTBE Production

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Metal Recovery and/orConcentrationIon exchange resins may be used toselectively isolate and concentratethe desired metal where it is a minorcomponent in a large stream or com-plicated mixture. Listed below areseveral examples of this chemicalprocessing capability.

Uranium Recovery. Of the manyprocesses using this concept, per-haps the best known is the recoveryof uranium from sulfuric acid leachsolution. DOWEX strong base resinsare used in this complex ion separa-tion process. The DOWEX 21K familyof resins (16-20 mesh, 16-30 mesh,20-40 mesh) are used extensively inthis application. While the uranylcation predominates in acid solution,in sulfuric acid there is a minoramount of quadrivalent uranyl sulfateanion in equilibrium with the uranylcation. Successful use of a strongbase resin for uranium recovery isbased on the fact that the affinity ofthe resin for the quadrivalent uranylsulfate anion in acid solution is veryhigh. When removed by the resin, thecomplex ion is replenished byreestablishment of the equilibriumwith the uranyl ion. Uranium may beremoved from these leach solutionsto nearly undetectable levels. Resinregeneration is readily accomplishedby elution of the complex ion from theresin using a salt (other than a sul-fate) solution. Not only is the uraniumrecovered from the leach solution, itis also purified and concentrated.

Dow has applied its resin technology for making uniform parti-cle size to this application in the formof DOWEX 21K XLT resins. Here, all the beads are the same sizeresulting in faster kinetics, higheroperating capacities and lower chemical usage and cost.

Precious Metal Recovery. In therecovery of precious metals, many ofthe processes involve the formation ofcomplexes with cyanides or chlorides.These complexes are very oftenrecoverable by uptake on, and elution

elution with different strength acidsolutions.

Cobalt/Nickel Recovery andSeparation. For more than adecade, Dow has provided the cobaltrefining industry with the uniquechelating resin, DOWEX M4195.Among other valuable capabilities,this truly unconventional resin prod-uct selectively removes nickel fromvery strong cobalt electrolytes, evenat very low pH (<1). In addition, itcan be economically regenerated foryears of tough service. With a longhistory of excellent performance andreliability, several of the industriesnew cobalt processing facilities areturning to DOWEX M4194 as a lowcost hydrometallurgical processingoption.

from, a strong base anion exchangeresin. Platinum is often present ascomplex chloroplatinate anions inHCl solution. This complex anionhas an extremely high affinity for thestrong base resin, and is easilyremoved from the solution. Theaffinity is so high, that recovery ofthe platinum from the resin is doneby burning of the resin, a practicethat is economical due to the highloading of platinum on the resin andthe high value of platinum. Goldrecovery from cyanide plating rinsewaters and mining operations isaccomplished using this same gener-al approach.

Chromate Recovery. Chromic acidremoved by rinse waters from platingoperations may be recovered forreuse by ion exchange demineraliza-tion using a strong acid resin fol-lowed by a weak base resin such asDOWEX M-43. The chromic acid istaken up on the weak base resin andrecovered at a higher concentrationin the salt form by regeneration ofthe weak base resin with a base.This more concentrated chromatesalt is then converted to recyclablechromic acid by column contact withthe hydrogen form of a strong acidresin such as DOWEX MSC-1 H+

resin. The demineralized rinse wateris suitable for recycle in the process.

Copper Recovery Using ChelatingResins. Chelating resins are available which have functionalitybased on picolylamine derivatives(DOWEX M4195 and developmentalchelating resin XFS 43084). Thesefunctionalities form very strong com-plexes with various transition metals,and particularly so with copper, evenat low pH. This property allowsrecovery of copper from acid leachsolutions. The removal of copperfrom this strong complex with theresin can be done using strong acidsolutions or ammonium hydroxidesolutions. Since the resin can alsopick up other transition metals,recovery and subsequent separationcan be accomplished using selective

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26% HCI FeCI3 Solution

H2OFEED

26% HCIwith Iron

LOADING ELUTION

DOWEXMSA-1

Resin inChloride

Form

DOWEXMSA-1

Resin inFeCl4

FeCl4Destroyed in

Dilute Solution-Washes from

Resins

Fe Addsto ResinAs FeCl4Complex

Figure 2. Iron Removal from Concentrated HCISolution PurificationComplex mixtures of acids, alkalis orsalts can be purified using ionexchange resins as the followingexamples illustrate.

Iron Removal from Hydrochloric(Muriatic) Acid. Hydrochloric acidused in steel pickling baths becomescontaminated with iron. To maintainthe effectiveness of the bath, ironcontamination must be maintained ata low level. The strong base resin,DOWEX MSA-1, has a high affinityfor iron in high concentrations of HCland has been used to remove thecontaminating iron. The affinitywhich the resin has for the anioniciron complex decreases, as the HClconcentration decreases, facilitatingthe stripping of iron from the resinwith a water wash. The wash wateris pH adjusted to keep trivalent ironin solution in the effluent strip solu-tion. Figure 2 shows this operationschematically.

Nitrate Removal from Water.Nitrate levels in water must be keptlow to meet public health standards.DOWEX SBR or SAR anion resinsare used in their chloride salt form toreduce the nitrate to acceptable lev-els. Regeneration is readily carriedout using sodium chloride solutions.Sulfate ions in the water are alsoexchanged for the chloride ion.

Formic Acid Removal fromFormaldehyde Solution. Formicacid develops as a contaminant offormaldehyde solutions during manu-facturing. Weak base resins, such asDOWEX M-43 are used to removethe formic acid from formaldehydesolutions. Formaldehyde solutionsas concentrated as 55%, and at tem-peratures of 65°C, can be treated.Regeneration to the free base formis done with a suitable base.

Radium Removal from Water.Radium is often present in minewater and in ground water sup-plies around uranium mining operations. This radium can beremoved using DOWEX HCR-W2 or DOWEX MAC-3 resin in a watersoftening operation. Since the resinsload the hardness ions normally

found in ground water supplies aswell, the resin loading for radium isrelatively small. Dow has developeda radium selective complexer, desig-nated DOWEX RSC, which removesradium and barium from water.Since the resin accumulates radiumselectively, long runs are obtained.However, proper disposal of the usedcomplexer is mandatory. Appropriatelicenses are required for use anddisposal of the spent DOWEX RSC.

Aluminum Removal fromPhosphoric Acid Bright Dip Bath.With use, aluminum bright dip bathscontaining 75-80% phosphoric acidbecome contaminated with alu-minum. Disposal of the spent bathpresents a considerable problem.DOWEX HGR-W2 resin is used toremove the aluminum from the bathsolution, substituting the H+ ion in itsplace. The bright dip phosphoricacid bath is thereby reconstituted.The much cheaper sulfuric acidregenerant yields an aluminum sulfate solution, a more easily disposable waste.Iron Removal from PhosphoricAcid Pickling Solution. Steel pick-

ling baths containing 15-20% phos-phoric acid must have low iron levelsto function effectively. Since the pick-ling operation increases the iron con-tent in the bath, DOWEX HGR-W2resin is used to remove the iron,reconstituting the pickling bath.Sulfuric acid solution is the regener-ant chemical.Phenol Removal from AqueousSolution. Phenol contamination of aqueous solutions can beremoved using the strong base resin,DOWEX MSA-1. The affinity whichthe resin exhibits for the phenol moiety is so great thatregeneration with aqueous causticis not adequate. Regeneration iseffective however, when methanoland caustic are used in the regener-ation mode. Another option for phe-nol in water is DOWEX OPTIPOREpolymeric adsorbents. Here the phe-nol is adsorbed with other organicmaterials and can be regeneratedwith steam or alcohol.Chemical ConversionsApplications of ion exchange can

7

.9

.8

.7

.6

.5

.4

.3

.2

.1

.00 .25 .50 .75 1.0 1.25 1.50

FEED:7.84% Na OH11.6% NaCI

Flow Rate:1.7 1/hr./1

NaOH NaCI

Bed Volumes

Ce/

Cf

(Con

cent

ratio

n of

Effl

uent

/Con

cent

ratio

n of

Fee

d)

Figure 3. Ion Retardation Separation of NaOH & NaCI

involve a chemical conversion of amaterial from one salt form to an-other. For example:

Silica Sol Production from SodiumSilicate. In the production of silicasol, a near colloidal form of silicaacid, DOWEX HGR-W2 H+ resin isused to replace the sodium ion ofthe sodium silicate with the hydrogenion. The reaction conditions are criti-cal, since the silicic acid formedbecomes insoluble and precipitatesout of the solution. Care must betaken to cause this solidification totake place outside of the reactioncolumn.

Fractionations/SeparationsA number of ion exchange process-es are chromatographic in nature.Several examples follow:

Acid Retardation Separation ofSulfuric Acid from Salts. Mixturesof sulfuric acid and its salts are sep-arated by passage through a bed ofDOWEX MSA-1 resin, which selec-tively imbibes the acid moiety rela-tive to the salt. The partition set upis enhanced by chromatographicoperating techniques when the elu-tion with water is applied. Since theacid is the imbibed species, separa-tion from large organic salts is alsofeasible.

Ion Exclusion Separation ofGlycerin from Salts. Using similarchromatographic operating tech-niques, glycerin has been separatedfrom salts by passing the solutionthrough DOWEX HCR-W2 resin inthe compatible form. A partitionbetween the two is set up when gly-cerin is imbibed by the resin while thesalt is excluded by Donnan mem-brane exclusion effects.

Ion Retardation Separation ofSalts from Caustic. Caustic solu-tions (NaOH, KOH, etc.) are contam-inated with various levels of chloridesalts in some production processesand in some uses. These materialscan be substantially freed of the saltcontamination by treating a causticsolution through a specific DOWEX

ion retardation resin. The salts aretaken up on the resin as an ion pairleaving the processed caustic rela-tively salt free. The salt is strippedfrom the resin with a water rinse.See Figure 3.

Resins as DesiccantsDOWEX HCR-W2 cation resin in thesodium or potassium form can bedried and used as a desiccant.Column operation is generally used.

Ideal for Non-polar Solvents.Solvents such as the chlorinatedhydrocarbons are dried at shippingterminals around the country bypassing through beds of DOWEX

resin desiccants. The resin has amuch stronger affinity for water thanfor the non-polar solvent and there-fore very dry solvents result.

Reactivation Considerations.DOWEX resin desiccants are reacti-vated by drying at relatively low tem-peratures (150°C; 300°F). As such,they exhibit a significant advantageover other desiccant materials, suchas silica gel and molecular sieves.

For more information see“DOWEX Resins as Organic SolventDesiccants”.

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Batch Operation. Occasionally, thereactions being performed by theresin are so complete in a singlestage that agitated batch reactorsmay effectively be used. An exam-ple is a simple neutralization reac-tion. In this case, the reactors needonly to be fitted with some filtrationability to facilitate the separation ofthe resin from the reaction mass.

Batch testing is a useful way todetermine the chemical feasibility ofa desired separation. In thisapproach, equilibrium adsorptionisotherms are generated usingshake flask tests that allow the cal-culation of the capacity of a separa-tion media and an initial cost of agiven separation. A method fordetermining equilibrium adsorptionisotherms is described in thebrochure “Equilibrium IsothermTesting for Liquid PhaseApplications” (Form No.177-01721/CH 171-424-E).

Column Operation. Ion exchangeprocesses are, for the most part,carried out in flow-through columnoperations. Typical laboratory testbeds consist of glass or plastic tub-ing approximately 1 inch in diameterby 5 feet deep. Resin bed depth isgenerally fixed at about 3 feet. Theadditional column depth is to allowthe resin to be backwashed periodi-cally to reestablish a uniformlypacked bed and to clean any partic-ulate material from the bed whichmay have been filtered from thesolutions being processed. Also, insome applications resins may swellsignificantly and care must be takento avoid column breakage. (NOTE:Resin expansion requires that col-umn configuration be such that thevolume change can occur vertically.Tall, narrow columns might restrainthis expansion and cause strong lateral pressures to develop in the column, resulting in resin beingcrushed, or in a column being ruptured).

Flow is controlled by pumping orconstant head pressure devices.Analysis of the effluent can be bysample collection and testing, or byon-line instrumentation. Care mustbe taken to maintain the resin inliquid at all times. If air enters thecolumn causing channeling of flow,the bed needs to be backwashed torelease trapped air from betweenthe beads. For more information see “Equilibrium Isotherm Testing”.

Consider DOWEX Ion ExchangeResins for your ApplicationAs is obvious from the above discus-sion, DOWEX ion exchange resinsare used in many ways and in manyareas of application in the chemicalprocessing field. The above listingsare far from exhaustive. In addition,Dow’s experienced chemical pro-cessing specialists are willing towork with potential users to definethe resins to be used in their areasof need, including development ofspecial resins if the potential war-rants.

For general information contact:http://www.dow.com/liquidseps

For chemical process applicationscontact: hrgoltz@dow.com

For mining and metal separationapplications contact:cmarston@dow.com

Visit our website athttp://www.dow.com/liquidsepsfor additional information.

Laboratory - Evaluation Considerations

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Applications and Recommended DOWEX Resins

CatalysisMethyl tertiary-Butyl Ether DOWEX M-31Phenol Alkylation DOWEX DR-2030Ester Hydrolysis DOWEX HCR-W2 Esterification DR-2030

DesiccationDesiccation of Organic Liquids DOWEX HCR-W2, Na+ form

Solution PurificationAcid Removal from Process Stream DOWEX M-43Formic Acid Removal fromFormaldehyde DOWEX M-43Amine Removal from Process Stream DOWEX MSC-1; DOWEX HCR-W2Iron Removal from Hydrochloric Acid DOWEX MSA-1Iron Removal from Phosphoric Acid DOWEX HGR-W2Aluminum Removal fromPhosphoric Acid DOWEX HGR-W2Chromate Removal DOWEX M-43Trivalent Chromium Removal from Chromate Solutions DOWEX MSC-1Trichrome plating bath purification DOWEX M4195Copper and Vanadium Recovery from Adipic Acid Manufacture DOWEX HGR-W2

Metal Recovery And/Or ConcentrationUranium Recovery DOWEX 21K; DOWEX 21K XLTCopper Recovery DOWEX M4195; XFS 43084Radium Removal DOWEX RSCCobalt/Nickel Separations DOWEX M4195Gold Cyanide Recovery DOWEX SBR; DOWEX G-55Platinum Metal Recovery DOWEX SBRCyanide Recovery DOWEX SBR; DOWEX G-55Phenol Recovery DOWEX SBP-P; DOWEX M 41;

DOWEX OPTIPORE L285 OR L493

Fractionation/SeparationSalt removal from base DOWEX Retardion 11A8

Styrene-DVB CopolymersFor lubrication, void space maintainers, grinding media, STYRENE-DVB Copolymer 18-50Pabsorption and decolorization and precision fillers. STYRENE-DVB Copolymer 14-40Other grades and sizes can be manufactured upon request

Polymeric Adsorbents

For Liquid ApplicationsHFCS Decolorization DOWEX OPTIPORE 44Sucrose Decolorization DOWEX OPTIPORE SD2Apple, Pear, Citrus Juice DOWEX OPTIPORE L285Pharmaceutical, Environmental DOWEX OPTIPORE L323Chem Process, Environmental DOWEX OPTIPORE L493

For Vapor ApplicationsHigher BP VOCs DOWEX OPTIPORE V323Medium BP VOCs DOWEX OPTIPORE V493Larger Particle Size DOWEX OPTIPORE V502Hydrophobic Adsorbent XUS 43565.01

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Notes

Form No.177-01395-602QRP

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Internethttp://www.dowex.com

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Warning: Oxidizing agents such as nitric acid attack organic ion exchange resins under certain conditions. This could lead to anything fromslight resin degradation to a violent exothermic reaction (explosion). Before using strong oxidizing agents, consult sources knowledgeable inhandling such materials.

Notice: No freedom from any patent owned by Seller or others is to be inferred. Because use conditions and applicable laws may differ from one location to another and may change with time, Customer is responsible for determining whether products and the information in thisdocument are appropriate for Customer’s use and for ensuring that Customer’s workplace and disposal practices are in compliance with applicable laws and other governmental enactments. Seller assumes no obligation or liability for the information in this document. NOWARRANTIES ARE GIVEN; ALL IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE AREEXPRESSLY EXCLUDED.

Published June 2002.

Dow Liquid Separations Offices.For more information call Dow Liquid Separations:

*Trademark of The Dow Chemical Company