Note: Descriptions are shown in the official language in which they were submitted.
ION EXCHANGE PROCESS IN~OLVING EMULSION
1~ }~XC~ANti;~ ~S I~S
Background of the Invention
The present invention concerns fine-particle-size
ion exchange resins and methods ~or their preparation.
In particular it concerns spherical, crosslinked emulsion
copolymer particles in a size range of from about 0.01 to
about 1.5 micrometers in diameter, which bear ion
exchange functional groups, and emulsions ~f these
particles. It further concerns the preparation of these
particles and emulsions, and the use of these particles
and emulsions in removing dissolved and undissolved
material from liquids.
Pinely divided ion exchange materials have been used
extensively as filter media for the simultaneous
filtration and deionization of condensate water from
steam turbine generators, and to a lesser extent in
pharmaceutical applications such as drug carriers and
~ablet disintegrators, and in other commercial
~0 applications.
In the past such finely divided ion exchange
materials have been produced by grinding or otherwise
physically reducing the size of ion exchange particles
produced by conventional processes involving the separate
i 25 steps of poly~erîzation -- most commonly suspension
; polymerization -- and func~ionalization.
. : .
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-- 2
Schultz and Crook (I & EC Product Research and
Development, Vol. 7, pp. 120 125, June, 1968) have
produced partlcles of ground lon exchange resin with
average diameters of one mlcron or smaller, but the
partlcles are not spherical, and the range of dlameters
wlthln a given sample of such materlals ls large~ i.e.,
the partlcles are not uniformly slzed. Even though
large partlcles may constitute only a small fractlon of
the total number of ground particles, they represent a
much larger fractlon of the sample weight. As a
result, such ground reslns exhiblt settllng of a
signirlcant fractlon of the lon exchange materlal
welght from aqueous suspenslon.
- Suspenslon polymerization lnvolves suspending
droplets o~ organlc llquid contalnlng monomers 9
polymerizatlon inltlators and suspenslon stabllizers in
an aqueous-phase medlum. The droplet slze, largely a
functlon of agitatlon rate, controls the ~lnal polymer
partlcle size, which normally ranges down to about 40
mlcrometers, although slzes down to 5 mlcromekers (US
Patent 3,357,158) or 10 micrometers (US Patent
3,991,017) have been disclosed. Ion exchange materlals
have also been produced by bulk polymerizatlon.
Physlcally reduclng the particle slze of such polymers
in bulk or bead ~orm to sub-mlcron slzes ls dlfflcult
and expenslve, and produces materlal wlth undeslrable
physlcal characterlstics such as lrregular particle
shape and broad partlcle-slze dlstrlbutlon. It may
also produce undeslrable heat degradatlon of the resln.
Sub-mlcron slzed, spherlcal polymer particles have
been prepared in the past, lncluding some with limited
ion exchange functionallty. These particles were
~, .... .
prepared rrOm monomers which contained ion exchange
functlonal groups, such as acrylic and methacryllc
acid, or dialkylaminoalkyl acrylates and
methacrylates. In most cases the polymerlzatlon
reactlon used was emulæion polymerizatlon. Thus Haag
et al (U.S. Patent 3,847,857) used "...from 5 to 70% by
weight...of one or more monomers containing an amine or
quaternary ammonlum group..." (column 2, llnes 56-59)
ln forming a functional, cros~linked emulsion ion
exchange resin for use ln palnts and other coatings.
Rembaum et al (U.S. Patent 3,985,632) similarly
prepared chromatographic adsorbents by emulslon
polymerizlng monomer mlxtures contalning minor amounts
of monomers wlth amlne functlonallty (column 5,
llnes 25-46). Fitch (U.S. Patent 3,104,231) used up to
15% by weight of monomers containlng carboxyllc acid
groups when preparlng crossllnked emulslon
copolymers. He cautlons that higher content of such
monomers leads "to elther solublllty of the copolymer
ln water or dllute alkali or slgnificant swelling of
the copolymer ln ~uch aqueous medla." (column 6,
llne 70 - column 7, line 4).
Hatch (U.S. Patent 3,957,698) describes a
precipitation polymerization for maklng crossllnked,
spherlcal ion exchange resin particles in a size range
similar to that of emulsion polymer partlcles. The
precipltatlon process inherently produces larger
particles, in the range of 0.1-10 micrometers (compare
0.01-1.5 mm for emulsion polymerizatlon)) and involves
the precipitation of polymer particles from a monomer-
solvent solution ln which polymer is insoluble. In
emulsion polymerization the monomer is only slightly
~oluble ln the solvent, and the polymer particles are
formed when monomer-swollen soap mlcelles contact
solvent-phase-initlated polymer chains. Hatch mentions
that "sultable micro bead resins can be prepared by
suspenslon or emulsion polymerization..." He then
describes suspenslon polymerization but fails to
indicate any detail of an emulsion polymerization
process (column 3, lines 30-40). The ion exchange
microbeads of Hatch are weak acid reslns made from
carboxylic acid monomers such as acrylic or methacrylic
acld, although the uRe of esters of these acids is
mentloned, wlth hydrolysls subsequent to
polymerlæatlon. Hatch exempllfles the preparation of a
microbead from vlnylbenzyl chlorlde (Example 43, but
the partlcle slze (3-7 microns~ ls clearly outside the
range of the present inventlon, and no attempt ls made
to lmpart lon exchange functionallty to the mlcrobead
itself untll it has been incorporated ln an ion
exchange resin matrlx. Hayward (U.S. Patent 3,g76,629)
also prepared weakly acldic cation exchange resins of a
size '~less than 2~ microns" using a modified suspension
polymerization and carboxylic acid monomers.
Tamura (Nippon Kagaku Kaishi 76 (4), pages 654-8,
1976) discloses the preparation of strongly acidic
catlon exchange resln material from emulæion
copolymers. Tamura coagulated styrene-divinylbenzene
copolymer emulsions and functionallzed them with fumlng
sulfuric or chlorosulfuric acids. He subsequently
mlxed the coagulum into a polypropylene membrane, but
dld not teach that the coagulum might be re emulsified.
The Inventlon
According to this lnventlon a novel class of
.,
.55i~
small-particle-size, spherlcal lon exchange reslns,
having partlcle diameters smaller than those hereto~ore
known ln the art, has been discovered. These resins
are prepared from crossllnked emulsion copolymer
partlcles, and may possess a degree of
functlonallzation greater than about 0.7, and as high
as about 1.5, functional groups per monomer unlt. The
process by whlch these resins are prepared involves
functionalization of the emulsion copolymer particles
wlth weakly acidic, strongly acldic, weakly baslc or
strongly basic lon exchange ~unctional groups. The
emulsion copolymer particles may be ~unctionalized
dlrectly, as by hydrolysls, sul~onatlon, and simllar
reactlons, or indlrectly by such reactions as
chloromethylation followed by a functionalization
reaction such as amlnation. To facilitate handling of
the particles, the emulsion may be coagulated, and the
large coagulum particles handled like large polymer
beads for lsolation and reaction. Alternatively, the
emulslon copolymer partlcles may be dried prior to
functionallzing them. After functionalization the
partlcles ~ay be resuspended as an emulslon of discrete
particles by high-shear mixing, ultrasonic vibration5
mild grindlng or other comminuting method which
disrupts the agglomerated pieces without damaging the
spherical partlcles of the emulslon lon exchange resln.
The ion exchange resins of this invention may be
prepared in narrow particle-size ranges with mean
values ln the submicroscopic range (which term, as used
hereln, means having particle diameters below about 1.5
mlcrometers), variable from about 0.01 micrometers to
about 0.5 micrometers ln diameter, and by the use of
~. J
special technlques, to as large as about 1.5
micrometers ln dlameter~ They may be prepared as
catlon or anion exchange re~lns, that is, with strongly
acldic, strongly baslc, weakly acldic or weakly basic
functionallty.
The lnventlon, in a further aspect, resides ln a
process for changlng the ionic form of a plurallty of
ion exchange resins of the same lon exchange type, at
least one of the reslns being in the physical form of
approximately spherical~ submlcroscoplc beads and
lnltlally belng substantlally ln a flrst lonlc form,
and the balance of the resins being ln the physical
form of macrobeads and inltially being substantially in
a second lonlc form, which process comprises contacting
the macrobeads in the second lonic form wlth an
emulslon of the submicroscopic beads ln the first ionic
form until ion exchange occurs between the ions of the
submicroscopic beads and the lons of the macrobeads.
This aspect Or the inventlon is disclosed and claimed
in Canadlan Application No. 335,831 of Berni P. Chong,
filed September 18, 1979, of whlch the present
application ls a dlvislonal.
In the Drawings:
Figures 1-3 and 4a-4d are electron
photomicrographs of typical lon exchange materlals of
~he present lnvention. Figures 1-3 are
photomlcrographs of three dif~erent slzes of anion
exchange emulsion reslns in the hydroxyl form, at a
magniflcatlon of X50,000. Flgures 4a-4d are
photomlcrographs of a slngle floc at four dif~erent
magnifications; khe floc was prepared by mlxlng a
cation exchange emulslon resin with an anion exchange
i `"'7
emulslon resin. Each of the materlals shown ln these
photomicrographs was prepared by methods taught hereln.
Figure 1 shows a strongly baslc anlon exchange
emulslon resin ln the hydroxyl ion form, derlved from a
copolymer contalnlng 3% (weigh~) divinylbenzene and
prepared according to Example 14 below, coagulated
according to ~xample 2 belowJ chloromethylated and
aminated accordlng to Example 17 below, and converted
to the hydroxyl form accordlng to Example 21 below.
~lgure 2 shows a strongly baslc anion exchange
emulslon resln ln the hydroxyl ion form, derived from a
copolymer contalning 3% (welght) dlvlnylbenzene and
prepared according to Example 1 below, coagulated
according to Example 2 below, chloromethylated and
amlnated according to Example 17 below, and converted
to the hydroxyl form according to Example 21 below.
Figure 3 shows the strongly basic anion exchange
emulslon resln in the hydroxyl lon form of Example 21
below.
Figure 4b shows the floc of Example 22 below at a
magnlflcatlon of X300; Flgure 4a shows the same ~loc at
a magniflcatlon of X1000; Flgure 4d shows the same floc
at a magnlficatlon of X3000; and Figure 4c shows the
same floc at a magnification of X10,000.
By referring to the partlcles shown ln the
~igures, lt may be seen that thece partlcles are
approxlmately spherlcal, that as prepared they have a
relatively narrow partlcle-slze dlstribution, and that
they may be prepared ln dlfferent partlcle slzes. The
3o partlcles of these flgures range ln size from about
0.017 micrometers to about 0.45 mlcrometers.
Although the figures lllustrate strongly baslc
'~
.. ! .
anion exchange emulsion resins, the partlcles of other
anion exchange emulsion reslns, and of cation exchange
emulsion reslns, have slmilar appearances and size
dis~rlbutlon.
The a~gregations of partlcles ln these ~igures
were concluded by the laboratory preparlng the
photomlcrographs to be artlfacts assoclated wlth
preparation o~ the samples for mlcrography.
In the case of strongly acidic and baslc, and
weakly baslc reslns, the formation of physically stable
coagula from the crossllnked emulslon copolymers makes
posslble the lsolation o~ the copolymers for
functionallzatlon. Because of their small partlcle
slze the emulslon copolymer particles cannot
practlcally be flltered or otherwlse separated from the
llqulds in whlch they are prepared, nor could
functlonalized copolymer partlcles be separated from
the functlonalization mixtures. After coagulatlon, the
large coagulum particles can be filtered and washed ln
much the same way as ion exchange resin beads of
conventlonal size. Functlonallzatlon of the coagulated
emulsion copolymer involves conventional reactions well
known in thi~ art.
Weakly acidlc emulslon copolymer resins haYe
physlcal properkies ~lmilar to those of the resins
described above, but they need not be coagulated prlor
to isolatlon and functlonallzatlon. A preferred method
of preparing the weakly acldlc resins of this lnvention
involves adding a crosslinked acrylic ester emulslon
3 copolymer to an alkali hydroxide solution. Upon
addition the emulsion may coagulate, but as the
copolymer ester linkages are hydrolyzed to form
.
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5~7
carbox~lic acid groups in the salt ~orm, any coagulum
formed re-suspends to form an emulsion of the salt o~
the functionalized resin. The functlonal groups o~ the
resin may then be converted to the free acid form by
treating the emulsion wlth a c~nventional, strongly
acldic catlonlc exchange resln in the ~ree acld ~orm.
The emulslon copolymer lon exchange reslns of this
lnventlon posses~ the followlng advantageous
propertles:
(a) regular, generally ~pherlcal shape,
(b) a high degree of structural rlgidity whlch ls
controllable by the degree of crossllnking in the
emulslon copolymer,
(c) a controllable, small particle size, the medlan
value of which may be varied from about 0.01 to
about 1.5 micrometers,
(d) a narrow particle slze range; photomlcrographlc
analysis shows ranges typlcally i 9 nanometers o~
the partlcle medlan dlameter for about 80% of the
particles,
(e) a large surrace area per unit weight, varlable
wlth partlcle dlameter ~rom about 4 square meters
per gram to as great as about 120 square meters
per gram, compared wlth about 0.1 square meter per
gram ror typlcal, small-dlameter conventlonal lon
exchange reslns,
(f) a high degree of ion exchange functlonality,
varlable to greater than one functlonal group per
monomer unit,0 (g) the abllity to form essentially non-settling
emulslons, except ln the largest partlcle sizes,
(h) a particle size lncrease on hydratlon, controlled
.
~6~
by the degree of crosslinklng ln the emulslon
copolymer, whlch is variable from about 10% to about
500% or more of the dry particle diameter,
(1) water insolublllty and negllglble water
extractabllity,
and deslrable sensible properties of
(~) subdued taste,
(k) ablllty to mask the taste of materials bound to
the resln,
(l) a smooth, non-grltty texture to the mouth, and
(m) a smooth, non-lrrltatlng texture to the skin.
The emulsion copolymers from whlch the ion
exchange resln of thls invention are derived may be
prepared by conventlonal emulsion polymerlzation
technlques. These techniques typically involve, but
are not llmlted to, polymerlz~ation of an emulsion
comprising the monomers and a surface-actlve agent.
The polymerlzatlon ls usually lnltlated by a water-
soluble lnitlator. It 18 well known that the action of
most such initlators is lnhlb$ted by the presence of
oxygen, so oxygen-exclud1ng technlques, such as uslng
lnert gas atmosphere and deoxygenated solutions and
emulslons, are preferably employed ln the
polymerization. The cholce of surface-actlve agents
and lnitlators wlll be apparent to one skilled in this
artO The monomers from which the emulsion copolymers
are derived comprise a ma~or amount of a
monoethylenlcally unsaturated monomer or mixture of
such monomers and a minor amount of a polyethylenlcally
unsaturated monomer or mlxture of such monomers which
act to crosslink the polymer. The followlng are
examples of monoethylenically unsaturated monomers
.
-- 10 --
useful ln preparing the emulsion copolymers: aromatic
monomers, including polycyclic aromatic monomers such
as vinylnaphthalenes and monocycllc aromatic monomers
such as styrene and substituted styrenes J whlch lnclude
ethylvinylbenzene3 vinyltoluen~ and vinylbenzyl
chlorlde; and acrylic monomers, the esters of
methacrylic and acrylic acid, such as methyl acrylate,
ethyl acrylate, propyl acrylate, lsopropyl acrylate,
butyl acrylate, tert-butyl acrylate, ethylhexyl
acrylate, cyclohexyl acrylate, lsobornyl acrylate,
benzyl acrylate, phenyl acrylate, alkylphenyl acrylate,
ethoxymethyl acrylate, ethoxyethyl acrylate,
ethoxypropyl acrylate, propoxymethyl acrylate,
propoxyethyl acrylate, propoxypropyl acrylate,
ethoxyphenyl acrylate, ethoxybenzyl acrylate, and the
corresponding methacryllc acid esters.
In the case of the acrylic esters, the preferred
embodiment employs lower aliphatic esters of acryllc
acid in whlch the aliphatlc group contalns from 1 to 5
carbon ato~s. Thls ls a partlcularly preferred
embodlment when the copolymers therefrom are to be
employed as lntermediates in the preparation of either
carboxylic cation-exchange emulsion copolymer reslns or
anlon-exchange emulsion copolymer resln~. In the
pr~paratlon of both the carboxyllc exchanger and the
anlon exchanger, the ester group is replaced. Thus,
the practlcal choice ls methyl or ethyl acrylate.
Suitable polyunsaturated cross-llnklng monomers
lnclude the following: divinylbenzene,
divinylpyridine, di~inyltoluenes, dlvinylnaphthalenes,
ethylene glycol dimethacrylate, divinylxylene,
dlvinylethylbenzene, dlvlnylsulfone, dlvinylketone,
., I
~ I
.5~
dlvinylsulfide, trivinylbenzene, trivinylnaphthalene,
trlmethylolpropane, trimethacrylate,
polyvlnylanthracenes and the polyvinylethers of glycol 3
glycerol, pentaerythritol, and resorcinol.
Partlcularly preferred cross-linklng monomers include
the following: polyvlnylaromatlc hydrocarbons such as
dlvinylbenzene and trlvinylbenzene, glycol
dlmethacrylates ~uch as ethylene glycol dimethacrylate,
and polyvlnyl ethers of polyhydrlc alcohols, such as
dlvlnoxyethane and trlvlnoxypropane. Aqueous emulslon
polymerlzatlon Or mixtures of ethylenically unsaturated
monomers are descrlbed ln United States Patent Nos.
2,753,318 and 2,918,391, among others.
As noted above, emulslon copolymer ion exchange
resins of thls lnventlon may be prepared with medlan
partlcle diameters from about 0.01 to about 1.5
mlcrometers; they may also be prepared in a range of
preferred medlan partlcle dlameters from about 0.01 to
about 0.5 micrometers. The median partlcle dlameter of
the resln may be accurately controlled withln these
ranges, and the dlstrlbutlon of partlcle dlameters
about the median value ls narrow, ~ar narrower than
distributions obtained wlth commlnuted reslns of small
partlcle dlameter. Control of the resln particle
diameter depends on the emulslon copolymer, even though
the partlcle slze ls increased by functionali~ation.
Such control of the emulslon copolymer particle
diameter ls well known. For example, within the
copolymer particle diameter range of about 0.05 to
about 0.3 mlcrometers the slze may be controlled by
varying the level of surface active agents present ln
the polymerlzation mixture, an increase in these agents
3~
- 12 -
tending to produce a smaller emulsion copolymer
particle. Crosslinker levels ln the polymer tend also
to exert an effect on copolymer particle diameter; more
highly crossllnked copolymer particles tend not to
swell as much when they hydratê as llghtly crosslinked
particles. Below diameters of about 0.1 mlcrometers
special surface active agents may be used to control
partlcle size down to about 0.01 micrometers as
lllustrated below in Example 14. Copolymer particles
larger than about 0.3 micrometers may be formed by
further reductlon of the level of surface active
agents, or by growing larger partlcles from "seed"
particles of pre-formed emuislon copolymers. Polymer
partlcles may be formed ln this way to as large as
about 1 micrometer in diameter; subsequent
functionallzation produced ion exchange resln particles
wlth diameters as large as about 1.5 mlcrometers J The
process of making large copolymer particles ls
lllustrated below ln Example 13.
Crosslinker levels may be selected between about
0.1% and about 25%, a more preferred range being from
about 1% to about 20%. Selection of crossllnker levels
depends upon the particular type of resin, physlcal
properties, and the level of functionallty deslred ln
the emulsion lon exchange resin product. For example,
sul~onic acld functionalized resins are prepared from
emulsion copolymers with higher levels of crosslinker
than copolymers for preparing amlne functionallzed
resins. SimilarlyJ if very low swelling is desired, a
processing advantage that permits the use of smaller
reactlon containers, higher crosslinker levels are
used. Ranges of about 3% to about 12% crosslinker are
~ill S~7
-- 13 --
typlcal for sulfonic acid ~unctlonallzed reslns with
low swelllng properties, and hlgher levels may be used
when exceptionally low swelling ls desired. Levels
above about 25% may be employed for speclal purposes,
~ so long as the crosslinker, as well as the
monoethylenlcally unsaturated monomer, may be
functlonallzed to produce a reasonable number Or
functlonal groups per monomer unit. Where more rapld
kinetlcs are desired, lower crosslinker levels are
selected. While anlon exchange emulslon reslns
pre~erably contain crossllnker levels between about
0.1% and about 7% or higher, they more preferably
contain from about 0.5% to about 3% crosslinker. The
selectlon of specific crossllnker levels to produce the
deslred balance of physlcal properties is well known to
those skilled with conventional lon exchange resins,
and the same guldlng princlp~es are used wlth emulslon
resins.
To permit further handllng, the emulsion copolymer
ls coagulated using one of several well-known
procedures. A preferred coagulation procedure is to
add the emulslon to a hot saline solution; aqueous
solutlons at concentratlons from saturated to about 2%
(wt) sodlum chloride or other lnorganlc salts such as
calcium chloride, aluminum sulfate and others may be
used. Aqueous sulfuric acld solutlons, concentrated to
about 4% (wt), are also suitable, and aqueous alkali
hydroxlde solutions such as those of potasslum or
sodium hydroxlde are especially ~uitable for
3o coagulation and slmultaneous hydrolysis and
functlonalization of acrylic ester copolymers.
Addltion of the emulsion to the stlrred coagulant
~,. I
- 14 -
solutlon allows the coagulum to dlsperse as particles
with slze dependent upon the stirrlng rate; the useful
slze spans a wlde range but for easiest handllng should
not fall below small granules i~to the powder range~
Addltion of the coagulant solution to the emulslon
18 posslble, but tends to produce an unwieldy
coagulated mass rather tha~ coagulum particles. The
emulsion may also be coagulated by drying lt; spray
drylng ls a preferred procedure for the preparation of
~trongly baslc resln product from an aromatlc
copolymer; the partlcles produced by thls procedure
tend to be too small for e~ficlent handllng when used
for functionalization reactlons that requlre subsequent
flltration and washing. Other useful procedures for
coagulatlng the copolymer emulslon include vlgorous
stlrrlng, alternating freezlng and thawing, and
addltlon of an organlc solvent to the emulsion.
Once produced, the coagulum particles are coherent
enough to withstand typlcal handllng techniques used ln
the washing, filtration, and functionalization of
conventional, suspension-polymerized ion exchange
beads. The coagulum is preferably freed from ~ater by
evaporation at ambient or higher temperatures, or by
rinsing with a water-miscible, dry, organic solvent~ to
prepare it for convention functionalization reactions.
In general the reactions employed to functionallze
emulsion copolymer ion exchange resins are the same as
those used to produce ion exchange resins from
conventional, suspension-polymerized copolymers. As a
3~ high degree Or functlonalization ls deslrable because
it produces a large number of functional ion exchange
sltes per unit welght of resin, the emulsion ion
i
~3~6
- 15 ~
exchange resins of the present inventlon are
functionallzed to between about 0.7 and about 1~5
functlonal groups per monomer unit. The more preferred
range is from about o.8 to about 1.2 functional groups
per monomer unit. The term, "functlonal groups per
monomer unit", as used herein, refers to the number of
lon exchange~functlonal groups per total monomer unlts,
both "backbone", monoethylenically unsaturated monomer
and crossllnklng, polyethylenically unsaturated
monomer. For example, ln the case of an aromatlc
backbone monomer and aromatlc crosslinker monomer used
to prepare a copolymer, this term would refer to the
number of functional groups per aromatic ring in the
polymer. Simllarly, in the case of a copolymer with a
functlonalized acryllc backbone and an unfunctionalized
aromatlc crossllnker, the degree of functlonalization
wlll be the functlonal ion exchange groups per total
monomer unlts, both acrylic and aromatic. The degree
of functionalizatlon may be thought of as the number of
functlonal groups per mole of all the monomers which
constitute the copolymer. Some of the typlcal
processes for functionalizlng the copolymer are
lllustrated below.
Strongly acldlc emulsion copolymer lon exchange
resins of this invention may be prepared, for example,
by ~eating coagulum particles of crossllnked styrene or
substituted styrene emulslon copolymer with
concentrated sul~urlc acid to produce a sulfonlc acld-
functionalized resin, rinsing the product free of
3o excess acid ~ith water, and re-suspending the
coagulated emulsion partlcles by the processes
descrlbed above.
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- 16 -
Weakly acidlc emulsion copolymer ion exchange
resins Or thls invention may be prepared, for example,
by hydrolyzing crosslinked acryllc ester emulslon
copolymers with alkall metal hydroxide solutlons, to
form carboxyllc acid-functionallzed reslns. It should
be noted that thls partlcular procedure does not
requlre that~the emulsion be coagulated prior to
functionalizatlon; upon addition o~ the emulslon to the
hydroxlde solutlon coagulation may occur, but as the
ester llnkages are hydrolyzed any coagulum of the
copolymer resin re-suspends. The carboxyllc acid-
functionallzed resln produced by thls procedure ls ln
the alkall metal ~orm, and may be converted to the free
acld (hydrogen) form by contactlng lt wlth a
conventional, strongly acldlc catlon resin ln the
hydrogen form. Slmllarly, acryllc ester copolymer
reslns may be hydrolyzed wlth strong ac~ds to produce
carboxylic acld-~unctionallzed reslns in the hydrogen
form, but ln this case the product is a coagulum rather
than an emulslon.
Strongiy basic emulsion copolymer ion exchange
reslns of this lnvention may be prepared~ for example,
by chloromethylatlng coagulated particles of
crosslinked styrene emulsion copolymer with
chloromethyl methyl ether ln the presence of a Lewis
acld such as aluminum chloride, and treating the
resultlng lntermediate emulslon copolymer material with
a tertiary amine such as trimethylamlne t~ ~orm a
quaternary amlne chloride ~unctional group.
Alternatively~ a strongly basic quaternary amihe resin
may be prepared by treating a croRslinked acryllc ester
emulsion copolymer with a diamine containing both a
I
-- 17 --
tertiary amlne group and a primary or secondary amlne
group, such as dimethylaminopropylamine or
di(3-dimethylaminopropyl)amine, and quaternizing the
resulting weakly basic resin with an alkyl halide such
as methyl chloride.
Weakly basic emulsion copolymer lon exchange
resins Or thi~ invention are prepared, for example, in
the same manner described for strongly basic resins,
except that for a styrene copolymer primary or
secondary amlnes are emplo~ed instead of tertlary
amlnes, and for an acryllc ester copolymer the resln is
not quaternized with an alkyl hallde.
While the functlonalized coagulum particles
possess ion exchange propertles, and are sufficiently
cohesive that they may be used in conventlonal ion
exchange processes in much th~e same manner as
conventional resin beads, a preferred form for
utillzing the materlals of this invention ls the re-
suspended form. Re~suspension of the functionallzed
coagulated particles may be achieved by the processes
described above, i.e., by high-shear mixing, ultrasonic
vibration, mild grinding, or other comminuting method
whlch disrupts the coagulum without damaging the
spherical resin particles. Spontaneous resuspension of
the emulslon partlcles occurs during preparation of the
strongly basic product from aromatic copolymers under
some condltions, eliminating the nee~ for a commlnuting
step~
It should be noted that the hydrophoblc nature of
the unfunctlonalized emulslon copolymer partlcies
encourages coagulatlon. Once ~unctionallzed the ion
exchange resln partlcles are relatively hydrophlllc;
` !
.
- 18 -
they tend not to coagulate from emulslon form under the
conditions suggested for the unfunctionallzed copolymer
emulsionsO Photomicrographic and other physlcal
evldence lndicates that the emulsions of the
functionallzed ion exchange re~sin particles tend to
contaln largely lndividual particles. On drying a
sample of su~h an emulslon the partlcles may remaln as
lndlvldual partlcles, or they may form small, loosely
bound clusters of partlcles. These clusters may be
disrupted by very mild force - rubblng between the
flngers ls often sufficlent - ln contrast to the
tightly bound nature of the coagula. m e loose
clusters also tend to dlsperse spontaneously upon
addltlon to water, to form emulslons of the lndivldual
resln partlcles.
In general 3 the emulslo~ copolymer lon exchange
resins of thls inventlon may be used ln any applicatlon
where ground lon exchange reslns, produced by bulk or
suspenslon polymerlzatlon, are used, but because of the
special propertles of the reslns of this invention,
they often prove superlor to ground reslns. In
addltlon, these special properties permlt reslns of
this inventlon to be used for a wlde varlety of
appllcatlons where ground resins are unsultable.
Among the uses for the reslns of thls inventlon
are those as orally admlnlstered medicines or medical
treatments. These include the use of the weakly acidic
resins in the calcium or magnesium form as gastric
antacids, of the strongly acidic reslns ln the sodlum
form ln treating hyperkalemia, of the strongly acidic
resins in the calcium form or the strongly baslc reslns
ln the chloride form ln treatlng hypercholesterolemla,
-- 19 --
and of the weakly acldic resins in the calcium form in
treatlng gallstones. Further such uses are as drug
- carriers and sustalned release agents for drugs and
other materials; in this applicatlon and others an
added advantage is the masking of ob~ectionable flavors
or odors of the adsorbed materials. The reslns may
further be us-ed ln the treatment of acute poisoning,
such as by heavy metals, drugs, and the endotoxlns,
exotoxlns, enterotoxlns and the like of mlcro-
organisms. Other u~es ln the area of lnteinal medlclnelnclude removal of pyrogens ~rom materlals whlch would
come into contact wlth the blood, removal of mlcro-
organlsms from the stomach and lntestlnes~ and use as
an lnJectable contrast medium for radiography.
Further uses of the resins of thls lnvention are
ln the area of external medlslnes and medical
treatments. These lnclude use as pH control agents,
for the treatment of contact dermatltls caused by
poison lvy or other agents, as antl-perspirants,
deodorants, and skln mlcroblocldes, as antl-irritants
either for thls property alone or whlle also servlng as
a drug carrler, and ln the treatment of bltes or stlngs
from lnsects, arachnlds, snakes and the llke.
Domestlc and industrlal uses of the resins of thls
inventlon are ln the areas of flocculation, riltratlon
and delonlzation. Comblnlng the strongly acldic resins
ln the hydrogen form with the strongly basic reslns ln
the hydroxyl form produces a floc which may be used as
a flltratlon and deionizatlon medium for condensate
water9 or as a flocculant and filtratlon ald for
fermentation broths. The strongly basic or weakly
basic resins may be used to remove free acids from
.
~P~ 9~
- 20 -
edible oils and for decolorizing crude sugars and
molasses. The strongly basic and weakly basic resins
may be used to remove fulvic and humlc acids ~rom
potable water, and to blnd and remove micro-organlsms
from such water~ The floc formed by comblning weakly
acidic and weakly baslc reslns may be used for
deionization-of water, crude sugars and the like. The
floc formed by combining strongly basic and strongly
acidic resins may be used for demineralizatlon of
process fluids, crude sugars, whey, and the llke.
Further uses for the resins of thls invention are
as additives to paper and nonwoven textile materials.
They may be incorporated into disposable dlapers and
sanitary napkins as deodorants and anti-bacterial
agents. They also serve as dye acceptors for
incorporation into paper, te~tiles and paints; in this
appllcation they may alæo be blended into polymers
prior to flber extrusion.
Further uses for the resins of this inventlon are
as formulatlng aids for agricultural products. They
may serve as controlled-release substrates for
blologlcally active materlals, lncluding pesticides,
fertilizers, growth hormones, minerals and the like, as
suspenslon alds ~or pesticide formulations and simllar
applications where thelr emulsifiabillty and ion
exchange activity are desirable, and as pH control
agents.
Still ~urther uses for the resins o~ this
lnvention are in the area of catalysis and
scavenging. They may serve as high-surface-area,
heterogeneous acid or base catalysts, ~or example, in
the conversion of cumene hydroperoxide to phenol and
~, !
~ . ., .~. .
!
r9~7
- 21
acetone, as an acld acceptor, for example, in the
synthesis of ampicillin, and as a scavenger for
products, by-products or metabolites to shlft reaction
equlllbria toward completion. They may serve as enzyme
actlvators, for example~ ln fructose conversion, and as
substrates ~or immobilizlng enzymes. The dr~ resins
may be used as deslccants for organic solvents.
Miæcellaneous uses for the reslns of this
invention include use of the weakly acidic resins ln
synthetic detergents as sequestering agents and
replacements for phosphate builders; use, especially of
the weakly acidlc reslns in the potassium for~, as
tablet disintegrating agents; and use as extractants in
hydrometallurgy, for the recovery of germanium,
uranium, zinc and the llke. The small si~e of the
reslns allows their use in ultrafiltratlon appllcatlons
within the lumens of flne hollow fibers. They may be
used RS ion exchangers or adsorbents rOr removing
metals or metal porphyrins from petroleum reslduesO
They may be used as high-surface-area extractants for
the puriflcation of organlc acids such as lactlc,
citrlc~ tartaric and slmilar ~clds produced by
fermentatlon. They may be used to remove proteins and
amino acids ~rom the waste water of sugar refinerles,
slaughter houses and the like~ and the resulting loaded
reslns, because of their pleasant mouth feel and lack
of taste, may be fed dlrectly to domestic animals such
as cattle.
Sugar decolorization and clarlfication uslng
emul~ion ion exchange resins of the present lnvention
offers slgnlflcant advantages over conventlonal
processes. Conventlonally raw sugar solutions are
- 22 -
treated wlth regenerable adsorbents such as bone char,
actlvated carbon, or conventional lon exchange
resins. These adsorbents require chemical regenerants
or heat for regeneration, and produce undesirably
dllute sugar solutions. In most refineries several
decolorization operations follow the clarification
operations, often including a sulfur dioxlde bleach,
addition of non-recoverable powdered carbon, or use of
a rlocculatlng agent. The emulsion resins of the
present lnventlon permlt a slngle-step decolorization
and clarifi¢ation. When added to lmpure sugar
solutlons they form coherent, fllterable flocs with the
charged partlculate impurities usually present in such
solutlons. Although the resin particles are
incorporated into the floc, they retain their ion
exchange functionallty, and therefore remove dissolved
ionic impuritles and color-imparting impurities from
the solutions. They further remove particulate and
color-lmpar~ing impurities elther by co-preclpitation
during the formatlon of the floc, or by retalning such
impurlties durlng flltratlon of the floc-contalnlng
solution. Yet another mechanlsm by whlch the flocs
remove lmpurltles from the solutions ls adsorptlon onto
the partlcles which comprlse the flocs; being extremely
small, these particles contribute high surface area to
the flocs~ By one or more of these mechanisms the
emulslon lon exchange reslns of thls lnvention remove
from the sugar solutions the lmpurlties which impart
color and lack of clarity, and addltlonally salts and
the precursors to the color lmpuritles. The flocs
containing adsorbed and entralned impurities may be
removed from the sugar solution by filtration,
~; '
37
flotatlon or other known processes. The sugars whlch
may be treated include cane, corn, beet and other
sugars. The excellent kinetlcs o~ these emulsion
reslns, resulting from their fine partlcle size, allow
them to act far more rapidly as lon exchangers than the
conventlonal lon exchange resins heretofore employed,
and the flocs -themselves have the added advantage o~
actlng as a fllter aid. The use of the emulslon reslns
of thls invention for decolorizing and cl~rifylng sugar
solutions is illustrated ln Example 27 below.
In those cases where lnsufflclent charged
particulate lmpurities are present ln the impure sugar
solutlon to incorporate all of the added emulsion resin
lnto the floc, a separate flocculating agent may be
added to the solution. Such flocculating agents
lnclude both lonlc sur~ace-actlve agents havlng a
charge opposite that of the emulsion resln, nonlonlc
surface-actlve agents and ~lnely divided lon exchange
materials having a charge opposite that of the emulsion
resin. These ion exchange materlals may be ground
conventional resins or emulsion reslns.
While the preferred emulsion resins for sugar
decolorization and clarlflcation are anion exchange
emulsion resins and the strongly basic anion exchange
emulslon resins are most prererred, acidic, cation
exchange emulsion resins may also be used to treat
sugars, and especially to treat sucrose for the purpose
of inverting it. Inversion, the process of
hydrolyzing the 12-carbon sucrose to a mixture of the
6-carbon sugars, glucose and fructose, occurs in the
presence of certain enzymes or of hydrogen ions.
Strongly acidic emulsion cation exchange resins may be
. I
~.
~l~6~ 7
- 24 -
used to supply these hydrogen ions without lntroducing
undeslrable soluble anions into the sugar. Following
lnverslon the catlon exchan~e emulslon resln may be
removed from the lnvert sugar æolution with a
conventlonal flocculatlng agent or by addltlon of an
anion exchange emulsion resln such as a stron~ly baslc
emul~lon resln. When such an emulslon resin is used,
lt tends to further clarlfy and decolorlze the sugar
solutlon, and the floc whlch forms acts as a flltration
ald. The advantage of ~uch a process over conventional
treatment of sucrose solutlo~s in a bed of cation
exchange resln beads ls that a more concentrated, hence
more vlscous, solutlon may be treated wlth the emulslon
resln than wlth the bead resins.
As noted above, combining a cationic emulsion
copolymer resin wlth an anl~lc emulslon copolymer
resln allows the oppositely charged partlcles of the
two types of resins to lnteract and form a loose,
electrostatically bound floc. The floc has excellent
klnetic propertles for ion exchange because llqulds
readily penetrate lt, and because the lndlvldual
particles themselves are so small that they are readily
penetrated. The floc ls readlly dlærupted by shear
forces, but because the electrostatlc attractlon of the
opposltely charged partlcles remains, the floc re-forms
when the shear force ls removed. Becau3e of thls the
floc may be pumped by conventional, llquid-handling
pumps as though lt were a llquld. It may also be
supported on relatlvely coarse, low-pressure-drop
filter screens where the electroætatic attraction
mlnimizes particle sloughage during use. In addltion
to the delonlzation propertles, these flocs have
~ .
~...,,~.
~6~
- 25 -
excellent filtratlon properties, as shown by Example 25
below. The delonlzatlon and filtration properties of
these flocs may be utlllzed simultaneously, as when
removlng ions and particulate matter from steam
generator condensate water. In such an appllcatlon the
floc ls usually pre-coated onto the fllter cloth,
filter screen; fllter leaf or other mechanlcal fllter
means. The floc may be pre-formed by mixlng the
catlonlc and anlonlc copolymer resln emulslons prlor to
transferring lt to the filter ltself, or the floc may
be prepared ln the liquid to be treated and ~lltered by
addlng emulslons of the catlonlc and anlonlc emulslon
copolymer reslns to the llquld. In thls latter case,
entralnment of partlculate matter wlthin the floc as it
forms may be an addltional advantage. The flocs
descrlbed hereln may be prepa~ed by mixlng strongly
acldlc emulsion copolymer reslns wlth strongly baslc or
weakly baslc emulslon copolymer reslns and weakly
acldic emulsion copolymer reslns with strongly basic or
weakly baslc emulslon copolymer resins. They may be
formed by mixing particles of one or more catlonlc
emulslon resins wlth particles of one or more anlonic
resins; weakly acldlc and strongly acidic emulsion
reslns may be mixed~ as may weakly baslc and strongly
baslc emulslon reslns, and these mlxtures may be used
to form flocs. Emulslon resins havlng dlfferent
particle sizes may be mlxed to form flocs, including a
multipllclty of catlonlc emulslon reslns having
different sizes, or a multipllclty of anionic emulslon
resins havlng different sizes; such mlxtures are used
to control the texture, and hence the filtering and
other handling characteristics, of the flocs. The
., I
- 25a -
formation of flocs i~ lllustrated in Examples 22 and 23
below.
Flocs prepared from weakly acidic and weakly basic
emulsion reslnQ have the addltional useful property of
being thermally regenerable. ~hat ls, the floc may be
used to remove anions and cations from a relatively
cold llquld,~~and these anlons and cations may be
replaced with hydrogen and hydroxyl lons from a
relatlvely hot aqueous llquid durlng regeneratlon.
Such flocs dlffer from conventional thermally
regenerable reslns which are usually large, hard beads
contalnlng areas of both acldlc and baslc
functlonallty. Because the thermally regenerable floc
can form a large, coherent mass, it may be used with
moving-bed delonlzatlon equlpment. In such equlpment
the floc ls coated on a movl~g fllter support whlch
continuously transports the floc through a deloni~ation
section, where it contacts the cold llquld being
treated, and through a regeneratlon section, where lt
contac~ a hot, aqueous regeneration llquld. It may
similarly be used in contlnuous-delonlzatlon processes
ln whlch the floc is clrculated by pump1ng through a
delonlzation vessel and a regeneration vessel, the floc
moving through the deionlzation vessel in a dlrectlon
opposite to the flow of treated liquid. The thermal
regenerability of the weak acld-weak base flow at two
dlfferent pH values, and a comparison of lts thermal
capaclty with that of a co~nventional thermally
regenerable bead resin is illustrated ln Example 24
below.
In the formatlon o~ flocs upon mixlng cationic and
anlonic emulsion resin materlals, a single partlcle
?~ I
- 26 -
establlshes an electrostatlc attraction for more than
one partlcle of opposlte charge. Especlally where
larger particles of one charge, as for lnstance
partlcles between about 0.7 and about 1.5 micrometers
ln diameter, are mlxed wlth rlne partlcles, as for
instance those wlth diameters smaller than 0.1
mlcrometer, of the opposlte charge, many fine particles
may cluster about the large partlcles. As a result the
ratlo of catlonic emulsion resln to anionlc emul~lon
re~ln in flOcs may be varied over a wlde range by
ad~usting partlcle slzes. Flocs may be prepared with
the cationic resin to anlonlc resln ratio ranglng from
about 9:1 to about 1:9. Even ln the case of partlcles
of opposlte charges havlng approxlmately the same
dlameter the catlonlc resln to anlonic resln ratio may
be varied over at least the range from about 3:~2 to
about 2:3; thls is a preferred range, regardless of
diameter. A more preferred ratio of cationic resln to
anionic resin is about 1:1.
The emulslon copolymer ion exchange reslns of thls
inventlon may be changed from one lonic form to another
by contactlng them wlth conventlonal lon exchange
resins, that ~s, wlth lon exchange resins having
particle sizes of about 40 mlcrometers or larger, and
preferably those reslns suited for use in conventlonal
ion exchange beds. Particles o~ ion exchange resln
having diameters of about 40 micrometer~ or greater are
referred to herein as "macrobeads", regardless of
whether they are spherical beads or of other geometric
shapes. For example, an emulsion anion exchange resin
prepared in the chloride form may be changed to the
hydroxyl form by passing an emulsion of the resln
!
.~ '
.
- 26a -
through a conventlonal bed o~ strongly basic anlon
exchange resin in the hydroxyl form. Chloride ions of
the emulsion resin are exchanged for hydroxyl lons of
the conventional large-bead resln as the emulslon resin
passes through the column. Because the lons are
exchanged by each resin, the lonlc form of the
conventlonal re~ln ls also changed. This process may
therefore be used to change the ionlc form of the
emulsion resln to a desired form, or to change the
resins of fixed beds to a deslred ionlc form, as in ion
exchange bed regeneratlon. Indlvldual or mlxed
emulsion reslns, and lndividual or mixed conventional
resins, may be employed in this process. The emulsion
resins are preferably of the same ion exchange type as
the conventlonal reslns; "ion exchange type" as used
herein meaning the ionic type of the lon exchange
functional groups: either substantially cationic
(acidic) or substantially anlonic (basic).
Ion exchange will occur between such resins both
ln a batch process, where the exchange i8 allowed to
reach equilibrlum, and in a column or bed process,
where continuous equillbratlon produces a hlgh
converslon to the deslred ionic form, ~ust as lt does
in conventlonal treatment of ionized solutions with ion
exchange beds. Thls process ls lllustrated ln
Examples 8, 19 and 21, below.
The ~ollowing examples are intended to illustrate,
and not to llmlt, the lnvention. All percentages used
herein are by welght unless otherwlse speclfied, and
all reagents are o~ good commercial quallty.
Thls example illustrates the preparation of a
~'
~ ~o
- 27 -
styrene-divinylbenzene emulslon copolymer. A monomer
emulslon i9 prepared by stlrrlng vlgorously under a
nitrogen atmosphere 370 g of deoxygenated water, 48.2 g
o~ Triton X-200 (trademark of Rohm and Haas Company,
PhiladelphlaJ Pennsylvania, for the sodium salt of an
alkyl aryl polyether sulfonate sur~ace-actlve agent
contalning ?8% solids), 348.8 g of styrene and 5I.2 g
of commercial-grade divinylbenzene (54.7%
divinylbenzene, balance essentially
ethylvinylbenzene). An aqueous lnitiator solutlon is
prepared by dissolving 2.0 g of potassium persulfate in
100 g o~ deoxygenated water, and 50 g Or the monomer
801ution iS added to the lnitiator solution. The
mlxture ls stlrred to develop a l-inch vortex and is
heated to 70C under the nitrogen atmosphere. When
polymerlzation begins, as evidenced by a Rudden
decrease in opaclty, the remalning monomer emulsion is
added over a period of 1.5 hours. The temperature is
held at 70C ~or one hour a~ter the addition is
completed. The polymer emulsion ls cooled to room
temperature and filtered through cheesecloth. The
measured sollds content of the emulsion is 43.0%,
- versus a calculated value of 45%.
Example 2
This example illustrates the brine coagulation of
the polymer emulsion prepared ln Example 1. A 1400-ml
quantity of 25% aqueous sodium chloride solutlon ls
heated to 100C. While stirring the solution, 700 ml
o~ the emulsion prepared in Example 1 are added at as
rapid a rate as is posslble wi$hout the solution
temperature ~alling below 95C. The solution
temperature i~ held at 100-103C for 30 minutes, and
- I
- 27a -
the solld coagulum ls flltered out on a USA Standard
Serles 150~m talternatlve deslgnation No. 100)
sieve. The coagulum ls rinsed with water and drled
overnlght at 100C; the yleld after drylng ls 292.1 g.
Example 3
This example illustrates the sulfurlc acld
coagulation ~f the polymer emulsion prepared in
Example 1. To 250 ml of stlrred, concentrated sulfuric
acid, 41 ml of the polymer emulsion of Example 1 are
added through a Pasteur plpette with lts tip beneath
the sur~ace of the acld. The resultlng vermiform
coagulum i8 about 1.5 mm ln diameter and 5-7 mm long.
Example 4
Thls example illustrates the sulfonatlon of the
coagulum of Example 2 to form a strongly acldic cation
exchange materlal. A 20-g ~uantity of the dry coagulum
from Example 2 is mixed wlth 120 ml of concentrated
sulfuric acid and heated under nitrogen atmosphere with
stirrlng to 120C; lt is held at thls temperature for
5 hours. The reaction mixture ls allowed to cool, and
water is added as rapidly as posslble without allowing
the temperature to rise above 95C. The solid material
is allowed to settle, and the supernatant liquid is
removed. About 120 ml of water are added to the solid
materlal and then removed. The solid material is
transferred to a fllter tube, rlnsed with water and
dralned; the yield is 103.8 g of material with 31.7%
solids, The cation exchange capacity of this materlal
ls 5.22 milliequivalents per gram of the material in
dry, H+ form, compared with 5.26 meq/g theoretical.
It should be noted that theoretlcal lon exchange
capaclty and theoretical degree of functlonalization,
~ ' `
- 28 -
as used hereln, is ba~ed upon the assumption of one
functional group per aromatic ring (styrene resins) or
per monomer unit (acrylic reslns). Since this value
may be exceeded under certaln cpnditions, measured
values greater than "theoretical" may occur.
Example 5
Thls ex~mple lllustrateæ the chloromethylation and
amlnolysis of the coagulum from Example 2. A 20-g
sample of the dry coagulum from Example 2 ls ~welled in
a mlxture of 17 ml Or chloromethyl methyl ether and
69 ml of propylene dichloride. Whlle stlrring this
slurry a solution of 19 g of alumlnum chloride ln 25 ml
of chloromethyl methyl ether ls added slowly wlth
coollng, keeping the temperature at 32C or less
throughout the addltion. The reaction mixture is held
at 32C for 2 hours and then~ is cooled to 15C. Water
is added dropwise with coollng, keeping the temperature
to 30C or less. The aqueous layer ls decanted from
the swollen organic layer and the product is washed
twice with water, once with 4% aqueous sodium hydroxide
solutlon, and once again wlth water. The solid product
is filtered; its weight while still wet with propylene
chloride is 105 g. A 15-g sample of this
chloromethylated lntermediate is slurrled with water
containlng 40 mg of 1200-molecular-weight
poly(ethylenelmine). The mixture is heated and the
propylene chlorlde strlpped out The mlxture i8 cooled
and 9 ml of 25% trlmethylamine are added. The
temperature of the mlxture ls raised to 70C, held
constant for 5 hours, and raised to 95C to strip out
the excess trlmethylamlne. The resultlng solid ls
transferred to a filter tube~ rlnsed with water and
~. ,
,"'`'; '
~, . .
1 n~i~7
- 28a -
dralned; the yield is 14.6 g of material with a sollds
1~ ..
: 2 5
- 29 -
content of 35.9~. The anion exchange capacity of this
material is 3.64 meq/g of dry material in the chloride
form. Microanalysis shows it to have the following
composition:
C 67.1~
~ 8.49%
O 6.82%
N 4.82%
Cl 12.37%
13 (corre~te~ ~or O = ~zO)
N = 3.7 meq/g.
Cl = 3.8 meq/g.
Example 6
This example illustrates the aminolysis of a
vinylbenzyl chloride-divinylbenzene emulsion copolymer
coagulum. An emulsion copolymer of vinylbenzyl chloride
and divinylbenzene (commercial grade, containing 54.7%
divinylbenzene and the balance essentially
ethylvinylbenzene) is prepared according to the procedure
of Example 15 below; the copolymer contains 8%
divinylbenzene and has a measured solids conten~ of
29.6%. The emulsion copolymer is allowed to stand until
it coagulates, and 50 9 of the coagulum are slurried with
a solution of 0.15 9 of 1200-molecular weight
poly(ethyleneimine3 in 100 ml of water. ~he slurry is
heated to 60C, held at that temperature for one hour,
and transferred to a pressure reactor. To the reactor 40
g of 40~ dimethylamine and 5.4 g of 50% aqueous sodium
hydroxide solution are added. The mixture is stirred and
heated to 60~C, held at that temperature for one hour,
then heated to 87C and held at that temperature for
hours. The reactor is cooled and purged with nitrogen
and the reaction mix~ure is filtered. The solids are
rinsed with water and drained; microanalysis of a small,
dried sample of the solids shows the following
~.
5~?7
-- 30 --
values:
C81.59%
H9.00%
O2.52%
N6.57%
(results are corrected for O = H2O).
N = 4.8 meq/g, as compared to a theoretical value
of 5.3 meq/g.
Example 7
Thls example lllustrates the preparation of a
methyl acrylate-divinylbenzene emulsion copolymer. A
dlsperslon of 24 g of Triton X-200 ln 360 g of
deoxygenated water ls prepared under a nitrogen
atmo phere ln a l-llter, round-bottomed flask, and is
stirred to create a l-inch vortex. A mlxture of 29 g
of divlnylbenzene (commerclal grade contalnlng 55.2%
dlvinylbenzene and the balance essentlally
ethylvlnylbenzene) and 171 g of methylacrylate is added
to the aqueous dispersion, followed by 4 ml of freshly
prepared, 820 ppm ferrous ~ulfate solutlon and 50 ml of
deoxygenated water containing 1.0 g of ammonlum
persulfate solution. This mixture is stirred for about
15 mlnutes and cooled to 20C. A solution of 1.0 g of
sodlum metablsulfite ln 20 ml of water and 5 drops of
70% t-butyl hydroperoxlde are added to the mlxture.
After a 5-minute lnduction perlod the temperature is
observed to rlse to 80C durlng a perlod of 6 minutes,
and thereafter to fall slowly. After 30 minutes, the
mixture is cooled to room temperature and filtered
3 through cheesecloth. The solids content of the
filtered emulsion i8 determined to be 31.0%, as
compared to a theoretlcal value of 31.4~.
- 31 -
Example 8
Thls example lllustrates the hydrolysls and
resuGpension o~ the methylacrylate-dlvinylbenzene
copolymer Or Example 7 to produce a weak-acld-
functionalized ion exchange resln emulslon. A 200-g
sample of the emulslon produced in Example 7 is added
to a stirred solutlon of 57.4 g of 50% aqueous sodlum
hydroxide solutlon in 250 ml of water -- thls
represents a 20% excess Or base -- and the emulslon ls
observed to coagulate. Thls mlxture ls heated to 93C,
held at that temperature ~or 2 hours, and cooled to
room temperature. The coagulum ls observed to re-
suspend ln the sodlum hydroxlde solutlon durlng the
stlrrlng and heatlng perlod. The emulslon product is
dlluted to 800-850 ml with water and ls passed through
a column of "Amberlite IR-120" catlon exchange resln
(trademark of Rohm and Haas Company, Phlladelphia,
Pennsylvania, for a sulfonlc acid functionalized,
styrene/divinylbenzene gel catlon exchange bead resin)
in the H~ ~orm to remove the excess sodium hydroxlde
and convert the product to the ~ree acld form. The
sol~ds content of the resultlng emulslon ls 4.74%J and
the weak acid cation exchange capaclty is 9.4 meq/g of
dry polymer.
Example 9
~ his example lllustrates resuspenslon o~ the
functlonallzed emulslon copolymer coagula prepared in
preceding examples. The runctionallzed coagulum ls
trans~erred to a hlgh-speed blender container
3o (minibottle assembly of a "Waring Blendor"*,
*Trademark
..;~.,.
j
-- 32 --
model 7011-31 BL 41) and ~ust covered with water. The
blender ls operated at high or low speed for one-hal~
minute to twenty minutes, as required to re-suspend the
emulslon.
Example 10
This example lllustrates the aminolysls and
resuspension.of the emulsion copolymer coagulum
prepared as descrlbed in Example 6. A 17-g sample of
the coagulum 18 slurrled in 125 ml of water and 9.0 g
of anhydrous trlmethylamlne are added. The temperature
18 observed to ri~e to 33C; the slurry is further
heated to 65C, and the excess trimethylamlne is swept
off with a nitrogen gas stream. The resultlng product,
although very thick, is fully suspended. The solids
content of the emulslon is 16.3%.
Example 11
The partlcle-slze distrlbution of a sample of the
OH form of a strongly basic, emulslon copolymer ion
exchange resln, prepared a~ descrlbed ln Examples 1, 2
and 5 by amlnatlng a chloromethylated styrene-7%
dlvlnylbenzene emulslon copolymer wlth trimethylamlne,
ls measured by electron photomlcrography. The mean
partlcle dlameter ls 147 nanometers (1 mlcrometer =
1000 nanometers~, approxlmately 76% of the partlcle
diameters fall wlthln a 18-nanometer range, and
approxlmately 95% of the partlcle dlameters fall withln
a 33-nanometer range.
Example 12
The partlcle size dlstribution of a sample of
weakly acldic, carboxylic acid functlonalized, acrylate
emulsion copolymer lon exchange resin containlng 8%
divinylbenzene, ln the H form, prepared as described
- 33 -
in Examples 7 and 8, is measured by electron
photomlcrography. The mean particle diameter is
48 nanometers, approxlmately 84% of the particle
dlameters fall withln a l9-nanometer range, and
approximately 95% of the partIcle dlameters ~all wlthln
a 29-nanometer range.
Example 13
Thls example lllustrates the preparatlon o~ a
styrene-divinylbenzene emulsion copolymer havlng a
partlcle slze larger than 0.5~ m by a process whlch
lnvolves adding the monomer solutlon to a pre-formed
copolymer emulslon for polymerlzation. A monomer
emulslon is prepared by stlrrlng vigorously under a
nitrogen atmosphere 180 g Or deoxygenated water, 14.3 g
f Trlton X-200 377.8 g of styrene, 22.2 g of
dlvlnylbenzene (54% dlvlnylbe~nzene, balance largely
ethylvlnylbenzene) and o.8 g of ammonlum persulfate.
Vnder a nltrogen atmosphere ln a separate contalner
348 g of deoxygenated water ls stirred to develop a
l-inch vortex and is heated to 95C. To this 13 g o~ a
prevlously prepared emulsion copolymer is added,
followed by 1.2 g of ammonlum persulfate. (The
previously prepared emulsion.copolymer is a 3g
divlnylbenzene-styrene emulslon copolymer containlng
43.3% sollds, previously prepared accordlng to the
method of Example 1 and having a partlcle slze of
approximately 0.1~m.) The mixture ls stirred for 30
seconds and the monomer emulsion prepared above ~s
added dropwise during a 3.5-hour perlod; the
temperature ls malntalned at about 90C. When the
addition ls complete the temperature ls malntained at
90C for 30 mlnutes, after which 33.7 g of TRITON X-200
qs~
- 34 -
i~ added. The emulslon i3 cooled to room temperature
and flltered through cheesecloth. The measured solids
content is 36.5% ve~sus a calculated value of 42.4%.
Example 14
This example lllustrates the preparation of a
styrene-dlvlnylbenzene emulslon copolymer of ~ine
particle size; A monomer emulsion is prepared by
stlrrlng vigorously under a nitrogen atmosphere 90 g of
deoxygenated water, 2.73 g of Siponate DS-4 (trademark
Or Alcolac, Inc. for the sodium 3alt o~ dodecylbenzene
sulfonic acld), 123.5 g o~ styrene, 72.5 g of
dlvlnylbenzene (55.2% dlvlnylbenzene, balance largely
ethylvlnylbenzene) and 4.0 g Or glacial methacrylic
acid. Under a nitrogen atmosphere in a separate
contalner 350 g of water, 33.09 g of Slponate DS-4, and
1.0 g of potassium persulfate~are stirred and heated to
85C. The above monomer emulslon is added dropwise
during a 3.5-hour period while the temperature is
maintained at 85C. A solution o~ 0.4 g of ~otassium
persulfate ln 75 ml of water is added and the mixture
ls stirred at 85C for 2 hours. The product is cooled
to room temperature and flltered through cheesecloth.
The measured sollds content is 26.0% versus a
calculated value Or 27.0%.
Example 15
This example lllustrates the preparatlon of
vlnylbenzyl chloride-divinylbenzene emulslon
copolymer. A mixture o~ 1.0 g of potassium persulfate,
35.74 g Or Slponate DS-4 and 350 g Or deoxygenated
water are stirred under a nltrogen atmosphere. A
mixture of 171 g Or vlnylbenzyl chlorlde and 29 g of
dlvinylbenzene (55.2% divinylbenzene, balance largely
5~
- 35 -
ethylvinylbenzene) are added. This mixture ls cooled
to 0-10C and swept with nltrogen for 2 hours. A
solutlon of 1.0 g of potassium persulfate ln 50 g of
water ls added and the temperature is raised to 30~C
for 18 hours. A ~olutlon of 0.48 g of sodlum
bicarbonate in 20 g of water is added and the
temperature ls ralsed to 40C for 6-24 hours. The
product i8 cooled to room temperature and ls flltered
through cheesecloth. The measured solids content ls
29.6% versus a calculated value of 31.8%.
Example 16
This example illustrates the brine coagulation of
the polymer emulsion prepared ln Example 7. A 40 g
sample of polymer emulslon prepared in Example 7 ls
added to lOO ml of a stirred solution of 25% sodium
chloride ln water at 100C. ~he temperature is
maintained for 2 mlnutes and cooled to 50C. The solid
product is flltered and rinsed with water followed by
methanol. The sollds content of the water-rinsed
coagulum is 50%.
Example 17
Thls example illustrates the chloromethylation and
aminolysls of the copolymer emulslon prepared ln
Example 13. A sample of the copolymer emulslon
prepared in Example 13 was coagulated and drled
accordlng to the method of Example 2. A 44.4 g sample
of dry coagulum is swelled ln 403 ml of propylene
dichloride at room temperature for 1,5 hours. The
slurry ls stirred and 80.5 ml of chloromethyl methyl
ether ls added. The mixture ls cooled to 10C and a
solution o~ 34.5 g of aluminum chlorlde in 42 ml of
chloromethyl methyl ether is added dropwise over 20
- 35a -
minutes whlle the temperature is malntained at 10C.
The stlrred mixture is held at 10C for 4 hours; it is
subsequently added to 350 ml Or water with sufflcient
cooling that the temperature never rises above 3CC.
The reaction mixture ls dilutea with 250 ml of water,
stlrred for 30 minutes and the phases are permltted to
separate. The aqueous phase is decanted and the
organlc layer 1~ batch washed three tlmes with water,
once wlth 4% sodlum hydroxlde solutlon, and twlce more
wlth water. Approxlmately 25% of thls product, B0 ml
of 25% aqueous trlmethylamine, 3 g of 50% sodlum
hydroxlde solution and 120 ml of water are comblned and
heated to 65C during a 3-hour perlod. The temperature
ls then ralsed to about 75C and the propylene
dlchlorlde-water azeotrope ls stripped out. The
material ls cooled to 50~C and nitrogen is swept across
the surface of the stirred product to remove excess
trlmethylamine. The polymer emulslon product ls
allowed to stand overnlght and ls decanted from any
- small resldue of settled solid. The sollds content of
the product i8 17%.
Example 18
Thls example illustrates the aminolysls of a
chloromethylated styrene dlvlnylbenzene copolymer
coagulum prepared as described in Example 5. A 20 g
sample of a 7% dlvinylbenzene-styrene copolymer
coagulum
~ I
. - 36 -
prepared according to Example 2 is chloromethylated
according to the procedure of Example 5. Approximately
20% of the propylene dichloride-swollen product, 100 ml
of water, and 25 ml of 25~ aqueous trimethylamine are
stirred at room temperature for the two hours and heated
to 65C for five hours. The temperature is raised to
85C and the propylene dichloride and excess
trimethylamine are stripped out. The aminolyzed product
is a solid which is filtered and rinsed with water.
~
This example illustrates the conversion of a
hydrolyzed and resuspended methyl acrylate-divinylbenzene
emulsion copolymer from the salt form to the free acid
form by batch treatment with a strong-acid ion exchange
resin. A sample of 237.7 g (0.71 eq) of a methyl
acrylate-divinylbenzene copolymer emulsion prepared
according to Example 7 is hydrolyzed with 250 g of 12.5%
sodium hydroxide solution according to the prooedure of
Example 8. The resulting thick, homogeneous product is
slurried with 500 ml (0.9 eq) of Amberlite IR-120 ion
exchange resin (product of the Rohm and ~aas Company,
Philadelphia, Pennsylvania) in the ~+ form and rapidly
becomes more fluid. . The beads of Amberlite IR-120 ion
exchange resin are filtered and rinsed with water; the
combined filtrate and rinses weigh 672 9 (9.17% solids,
97% of theory). Microanalysis shows the following
results:
C=55.92%
~z6.18%
O=34OS4%
Na=144 ppm.
~?B~L
; This example illustra~es the amination of the
emulsion polymer coagulum prepar~d in Example 16, A
sample of the coagulum prepared in Example 16 is dried at
...... .. . ... . . . . . .
. , ~ . ,. . . ,~ . ~
- ~7 -
110C and 4 g of the dry solid is heated with 15 g of
bis(3-dimethylaminopropyl3amine to 230C for two
hours. The methanol produced is swept away with a
stream of nitrogen. The reactlon mixture ls dlluted
wlth methanol and the coagulum is flltered, rlnsed wlth
methanol and with water, and drained. The solids
content of the aminated product is 40% versus 50% for
the water-rinsed starting material.
Example 21
This example illustrates the lon exchange and
converslon of a strong-base-functionallzed copolymer
emulæion prepared accordlng to Example 17 from the
chloride form to the hydroxide form by means of column
treatment with Amberlite IR-120 and Amberlite IRA-400
lon exchange reslns (products of Rohm and Haas Company,
Philadelphia, Pa.), in the hydrogen and hydroxyl forms
respectively. A 5 ml sample ~f a strong-base-
functionallzed copolymer emulsion prepared according to
Example 17 is passed through a column of 8.55 ml of
Amberllte IR-120 ion exchange resin in the H~ at a rate
of 0.5 bed volumes per hour; it is washed through the
column with deionized water. The effluent is then
passed through a column of 7 6 ml of Amberlite IRA-400
ion exchange resin in the OH at 0.5 bed volumes per
hour and is similarly washed through the column with
deionized water. A total of 13.1 ml of effluent iæ
collected. A 4 ml sample of this effluent is titrated
to a pH = 7 endpoint with 4.35 ml of 0.1 N hydrochloric
acid. A 0.5 g sample of effluent and .56 ml of 0.1 N
hydrochloric acid are evaporated to dryness, yielding
0.16~ g of a æolid material; 2.99% solidæ in the
hydroxyl form is calculated. A titrable strong base
"~ ~
- 38 -
capacity of 3.64 meq/g is calculated.
Example 22
Thls example illustrates the preparation of a floc
from a strong-acid-functionalized copolymer emulsion
and a stro~g-base-functionalized copolymer emulsion. A
sample of 11 ml of a 0.5%-solids suspension of a
strong-base-r~nctionalized copolymer emulsion ln the
hydroxide form, prepared according to Example 5, column
treated wlth sodium hydroxide and resuspended as in
Example 9, and a sample of 9 ml of a 0.5%-sollds
strong-acid-functionalized copolymer emulsion prepared
according to Example 4 and resuspended as in Example 9
are comblned and shakenO The result is a solid floc
which settles, leaving a clear, supernatant liquid.
Example 23
This example illu~trates~the preparation of a floc
from a weak-acid-functionalized copolymer emulslon and
a weak-base-functlonallzed copolymer emulsion. A
sample of 5 ml of a 2.07% solids, weak-acld-
functionallzed copolymer emulsion prepared accordlng toExample 8 and a sample of 2.5 ml of a 3.97% solids,
weak-base-functionalized copolymer emulslon prepared
accordlng to Example 6 are combined and shaken.
Deionized water is added and the product ls a solid
~loc which settles, leaving a hazy supernatant liquid.
Example 24
This example illustrates the thermal
regenerabillty of the floc produced by combining weak
acid and weak base emulsion resins. A floc is prepared
according to Example 23, the quantity of weak base and
weak acid resin emulsions belng selected to yleld 0.2 g
of floc. This floc ls transferred to 16 ml of water,
;,,,~
- 39 -
and the pH is ad~usted to 5.6 by addition of dilute
acid or base, as required, with rapid mixing. Sodlum
chloride is added to the mixture until its
concentration in the liquid phase is approximately
100 ppm, and the mlxture is allowed to equillbrate at
room temperature. The speciflc resistance is
determlned to be 7200 ohm-cm, equlvalent to 70 ppm
~odium chloride. The mixture ls heated to 92C while
stlrrlng, and ls allowed to equlllbrate at that
temperature. Stlrrlng ls stopped, the floc is allowed
to settle whlle the temperature ls malntained, and a
portlon of the supernatant llquid ls transferred to a
conductlvlty cell. Thls sample ls allowed to cool to
room temperature, and its specific reslstance ls
determlned to be 4900 ohm-cm, equivalent to 102 ppm
sodium chlorlde. The sample.of supern~tant llquid is
returned to the total mlxture, whlch is then cooled to
room temperature. The pH and speciflc reslstance are
measured again, and are found to be equal to the
initial, room temperature values.
Thls procedure is repeated using a second sample
of the same floc, and agaln uslng a typical, thermally
regenerable, hybrld lon exchange resin, the preparatlon
of which ls descrlbed ln U.S. Patent 3,991,017. The
25 measurement results for these materlals are shown in
the followlng table:
;
;~i ' I
,
-
. ~16~ 7
-- 40 --
~I JJ
~a ~ ~ qJ
.e .
u~ I`
~ Q~ o o
s ~ . . tn
m
U
E V ~ t`~
,
P~ Z--~
~P
C E3--
~ J~ I
.~ ~ E~
; ~ o o S:
a~ ~Q o a~ o o ~ .C
a~ _ a~
U~ ~ r~ ~ ~ X
liil Q1
~ V ~0
_I O ~n
U ~o U~ 0
D A ~~
a~
~n .n
~ '
a~ ~ ~
.ri ~ V ~ ~ ~0
W ~ I ~ s.
E
S W o o C
0~ o o o
~,0 -- ~ ~ O
u~ ~; u~
U~ ~
.C _I
.. ~ ~
9)
n 04 _i
~ ~ V
~ U~ -~
U~
- 41 -
This example illustrates the use of a strong
acid-strong base floc for filtration of a finely divided,
suspended material from water. A floc is prepared
according to Example 22, the quantity of strong base and
strong acid resin emulsions being selected to yield 79.5
mg of floc containing 47~ cation resin and 53% anion
resin. This floc is transferred to a 1/2-inch (1.3 cm)
diameter glass tube containing a 100-mesh nylon screen.
A room-temperature ~spen~ion of 300 ppb hema~i~e (yellow
iron oxides) in water is allowed to pass through the tube
at a flow rate of 3.7 gpm/ft2 (18 ml/minute absolute
flow rate), at an inlet pressure of 25 psi ~1.70
atmospheres~. The pressure drop across the bed of floc
15 and the Silting Index of the effluent are monitored with
time. The determination is stopped after 630 minutes,
when the pressure drop approaches the 25-psi inlet
pressure, although the floc is still filtering
acceptably, as indirated by the Silting Index. The0 results of this determination are shown in Table II below.
The Silting Index is a number determined using the
Millipore Silting Index Apparatus (Millipore Catalogue
No. XX6801300), and is based on the times required ~o
deliver pre-determined volumes of liquid through a
0.45-micron Millipore filter. Silting Index is described
in Federal Tes~ Me~hod 5350.
. .. . . . . . . .. ..
. . . .
J~
- 42 -
TAB
Time, Minutes~ ~L~ ea~ Silting Index
2 ~.7
0.7
0.9 1.53
1.0
1.~ _
1.2
106 1.3 1.6~
160 1.4 0.81
208 1.~ 1.00
255 1~7 1.17
310 l.B 1.76
350 2.0 2.09
400 4.4 3.19
440 7.8 2.15
490 13.4 2.45
540 19.2 2.47
580 - 24.1 2.2~
630 ~4.7 2.20
.
_x2mple 26
This example illustrate~ the use of the strong
acid-strong base floc for deionization. A floc was
prepared according to Example 22, the ~uantities of
strong base and strong acid resin emulsion being selected
to yield 20Q mg of floc containing 40% cation and 60%
anion emulsion sesin. This floc was transferred to a
1/2-inch (1.3 cm) diameter glass tube containing a
100-mesh nylon screen. A solution containing 9.76 ppm
NaCl calculated as CaCO3 was allowed to pass downward
through the tube at a flow rate of 3.7 gpm/ft2 (18
ml/minute absolute flow rate) at room temperature, at an
inlet pressure of 25 psi (1.70 atmosphere). The pressure
- - 43 -
drop across the bed and the specific resistance of the
effluent are monitored. Breakthrough is defined as the
poin~ at which the ef~luent resi ~civity declines to 4 . O
megohm-cm (approximately 1096 leakage). This break'chrough
5 occurs at about 23. 5 minutes, and is equivalent to a
calculated capacity of 0.048 g Cl /9 dry anion resin.
The results of this determination are tabulated in Table
III below:
T~.BLE III
Specific Resistance
Time, MinutesPressure Drop, psime~ohm-cm
1 0 6.20
3 o 7.60
6 0 8.40
0 8.40
0 8.20
0 6.00
0 3.10
0 1.60
0 0.60
0 0.275
0 0.140
0 0.094
Exam~le 27
This example illustrates the decoloriza~ion of a
washed, raw sugar solution using emulsion ion exchange
resins. A 125-ml sample of washed, raw sugar solution,
t~pical of that received at refineries, and having an
ICUMSA color of 900 and a concentration of 65 Brix ~s
hea~ed t~ 80C. To this is added 0.20 g, dry basis
~equivalent to 2000 parts resin per million parts sugar
solids), of strongly bas;c anion exchan~e resin emulsion
in the chloride form, made from the emulsion copolymer of
~ 5~
Example 1, coagulated accordin~ to ~xample 2, chlor inated
and aminolyzed according to Example 17. The mixture is
stirred for five minutes, and is then transferred to a
pressure filter where it is filtered through diakomaceous
earth supported on coarse filter paper. The sugar
solution filters rapidly, and the filtrate is a
clarified, decolorized solution with an ICUM5A color of
180.
Tne ICUMSA color determination by Revised ICUMSA
Method 4 is described in the Cane 5ugar Handbook, 10th
Edition, published by John Wiley and Sons. This color
determination is made at a wave length of 420 nanometers
and a measured p~ of 7.0, and the result is extrapolated
to a sugar concentration of 100%.
Example 28_
This example illustrates the suspension in an
organic solvent of a floc prepared from cation and anion
emulsion resins. A 9-ml sample of strongly acidic
emulsion cation exchange resin, prepared according to
Exæmple 4 and resuspended as a 0.5~ solids emulsion
accor~ing to Example 9 is mixed with an ll-ml sample of
strongly basic emulsion anion exchange resin, prepared
according to Example 18, rinsed as a coagulum with 4%
aqueous sodium hydroxide solution to correct it to the
2~ hydroxyl form and resuspended as a 0.~% solid~ e~ulsion
according to Example 9, to form a floc. The floc is
transferred to a sintered glass filter funnel, allowed to
drain, and rinsed with acetone to replace the water from
the floc. The floc is observed to retain its flocculant
30 character in the non-aqueous, acetone medium. The floc
is subse~uently dried, first in a stream of nitrogen and
finally in an oven at 95~C. The dried floc is
photographed using a scanning electron microscope, and is
observed to have a microporous structure, that is,
relatively large void spaces exist within the structure
of cohered, emulsion resin beads.
, . . , , .. ~ , . .. ,.. . . ; . ,. . . ~. . . . .... .. ...... ...... .. . .
