CA1097846A - Free radical polymerization process employing novel substituted alpha amino acetic acid derivatives - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Ethylenically unsaturated monomers susceptible to free radical polymerization may be polymerized by contacting the monomers with an initiating compound having the formula:

Description

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I FIELD OF THE INVENTION
This ` invention concerns the polymerizatlon of ethylenic-a}ly unsaturated polymerizable monomers~susceptlble to frce r~adical polymerization. Specifically the~invention~concerns novel methods ~

for initiating polymerization of such monomers~and monomer systems ~ -containing inacti~ve initiators which~lnitiators~may be activated to polymerize the sy stem.
D~SCRIPTION OF TIIE PRIOR ~IIT
¦ Polymerization of ethy1en1cally uDsaturntecl monomers may be initiatcd by scveral mcthods wcll k~lown~o tlle ar~. ~ollle of these include the use of high énergy elcc~tromagnetic radiation such as gamma r;adiation and x-rays, ultraviole~ llight r2diation, chemical initiators, and thermal means. Many~polymerizatioll reactio ~s pend upon the formation of free radicals to~causc the initiatio~
f the polymerization. ;The use of free radical producing agents ~ontaining an acetic acid group has been disclosed in Chambers' .S~.~3,479,185. The Chambers patent disc10ses or exampl~ the use of~ a system of N-phenyl glycine or N,N,N~,N',-ethylenediamino 1; ~.
etra~acetio~acid in combination with a 2,4,5-triphenylimidazolyl dimer aa a photo po1ymerization catalyst. ~
It has now been discovered however that certain : ~ ituted~aromatic imino diaaetic compounds produce free ràdiaals and~ provide for excellent and versatile initiators thout the additional~presence of a dimer.
An add~itional advantage of the initiators of the en~t lnvèntion is~the1r versatility in that they can cause polymerlzation in presence or absence of air, oxygen, heat, visible or ultr~violet;light. ~

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While such sources of radiation energies are therefore not required, the presence of them as promoters will tend to increase the activity of the initiator and consequently the rate of polymerization.
SUMM~RY OF THE INVENTION
According to the invention there is therefore provided a method of polymerizing a monomer system containing one or more ethylenically unsaturated compounds su~ceptible to free radical polymerization which comprises initiating polymerization by contacting the system with an effective amount of a dissolved initiator o the formula:
Rl -N~(CH2COOH)2 where Rl is a substituted or unsubstituted aryl radical provided that the ethylenically unsaturated compounds do not contain "any group with which all the acid groups of the initiator will preferentially react chemically" ~as hsreinafter defined). According to the invention there is also provided a monomer system susceptible to free radical polymerization which comprises one or more ethylenically unsaturated monomers and an initiator comprising a dissolved compound of the formula Rl -N- (CH2C00~)2 wherein Rl is a substituted or unsubstituted aryl radical or a salt of said compound which salt upon acidification will yield said compound, provided that the ethylenically unsaturated monomers do not contain any group with which the acid group of the compound will preferentially react chemically. By aryl is meant a monovalent radical containing an aromatic ring where-in the free valence is on a carbon atom of the aromatic ring.
~ESCRIPTION OF THE INVENTION
An important limitation of the process of the -- 3 ~
--" - iO~7846 invention requires that the initiator must be soluble in at least one phase of a polymerizable system. This polymerizable system may be an emulsion, suspension or solution polymerizable system. Often the j - 3a -10~7846 ¦initiator is soluble in the polymerizable monorner or monomcrs and no a~itlonal solvent is rcquil-ed. ~lt~rnativcly in a polymerizable systcm, whcrc t~e initiator i.s no~ dircctly solublc in the monomer, thc system n-ust comprise a solvellt such as for cxamplc, watcr or mcthanol Eor thc initiator. Tllc tcrm . "dissolved ini-tiator" is therefore meant to include initiators : dissolved in the polymcrizable monomer and initiators dissolved in a solvcnt.
The initiating compounds which are useful in thc proccss of the invention include: ¦

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l-~OOC-CI-I Cll -COOIJ
-. il N- ~ 2 ~- ~ 2 HOOC-CH / Cil -COO~I
, p-methylenedianiline tetraacetic acid ¦ ilOOC-CH
\~ - / ~ CH -COOH
~ ~ ~ 2 m-phenylenediamir.e tetraacetic acid HOOC-Ci~2 CH2-COOH

l ~ _ l ~Cll -COOil ~C anilinediacetic acid ¦CH ~ ~ -N 2 p-toluidinediacctic acid 3 ~ ~cil2-COoH

Cl~ -COO}I
n-Bu- < ~ -N 2 p-tn-butyl)anilinediacetic acid Il I

~¦ CH
CH -~ ~ -N 2,4-dimethylanilinediacetic acid ¦ 3 ~ ~CH2-COO
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~CH -COOH
5 ~ -N 2,4-diethy1anilinediacetic acid .: .__._ . I

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~ '' OC1l3 C1130- ~ / 2 [(2,4-dimethoxypllenyl)iminoJdiaee~ie acid C~12COOII I .
i . '11 Ho - ~ N~CH2 1~4-hYdro~Yphenyl)iminoJdiacetic ~cid l ~C~12Coo~

Cl- ~ - N 2 ~4-ehlorophenyl)imino~dlacetie aeid ~C~I COOH
N~ 2 [(1,1'-biphenyl)-4-ylimino]diaeetie ~ ~ C112C0011 aeid j~ C~ICOOII
~ ~ ~N.~ 2 (2-naphthylimino)diacetie aeid 1 ~ ~ ~ CH2COOH
l l l ' cil2cooH
. N ~ (l-naphthylimino)diaeetie aeid ~ ~ 12COOI~

2 (~;3Cll;~COOII
[ (4-phcnylmetllylp}lcllyl)ir(lino]diacetic acicl 130~ _ 6_ l l - ll 10~7846 .~.' C1130 ~ _ N~ 2 [(9-methoxyphenyl)imino]diacetic acid ~ `C' 2C~l l Preferred initiatin~ compounds are those whercin 1~l has the ~fo110~ing f,rmula: R

¦where R is hyùrogen, a1ky1, a1ko~y, phenyl, ara1ky1, or alkaryl.
Preferred initiators showing high activity are those containing alkyl or alkoxy substituted aromatic ring c~roup.
Other preferred initiators also having hicJh activity are those containincJ two aromatic rings.
The initiators useful in the process of the invention may be prepared by reacting in an aqueous solutian the corresponding amine component with a slight excess of sodium chloroacetate at elevated temperatures. During the reaction, which is usually complete in 2 hours at reflux, the p~1 of the reaction mixture is carefully controllcd at abou-t 7 by the addition oE sodium hydroxide. After the reaction is completed ; the product may usually be obtained as the inactive sodium salt by stripping or alternatively aS anactive precipitate by acidiflcation such as with hydrochloric acid. In instances ¦1where precipitati~n will not occur after acidification, extraction procedures may be employed to obtain the product.

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~- 10~7846 Mc)llon~(r The unsaturated materials which may be polymeri~ed by llthe practice of this invcntion are ethylellically unsatura~ed ¦Icompounds susceptiblc to ~rec radical polymcrization. Tllcse ¦compounds include esters, nitrilcs and or~-lnic halo(Jcn compounds jwhich are cthylenically unsaturatcd compounds of both aromatic and aliphatic types. ~y way of illustxation, vinyl esters such as ~vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, ¦and other vinyl esters containing as many as 18 or more carbon atoms in the acid moicty, may be polymerized in accordance hcrewitll.
Other vinyl derivatives such as vinyl chloride, vinyl l fluoride, chlorotrifluoroethylene, tetrafluoroethylene, butadicne, ¦ nitroethylene, methyl vinyl ketone, methyl isopropenyl ~etone, buty 11 ¦Ivinyl sulfone, vinyl triethoxy silane, ethyl vinyl sulfoxide, styrene, nuclear substitut~d styrenes including o-methyl, m-methyl, p-methyl styrene, divinylbenzene, and other related compounds may alSo be polymerized in accordance hcrewith. Vinylidine derivatives, viz.~ vinylidene chloride, al~d vinylidene carbonate respond to this polymerization also.
The acrylates respond particularly well to the tech-niques disclosed herein and the invention extends to include acrylates and methacrylates containing up to 18 or more carbon atoms such as ethyl acrylate, propyl acrylate, butyl acrylate, isobutyl acrylate, cyclohexo acrylate, cyclohcxo methacrylatc, decyl I ¦ acrylate, dodecyl methacrylate, methyl methacrylatc, benzyl-acrylate, tetrahydrofurfuryl acrylate, 2-methoxyethyl acrylate, methyl Ichloroacrylate, pentaerythritol triacrylate, neo-pentylglycol ¦diacrylate, ethyleneglycol acrylate phthalate, 2-hydroxypropyl I ;methacrylate~ 2-hydroxyethyl acrylate and other related compounds such as acrylamjde, acrylic acid, methacrylic acid rcspolld to ¦treatme;lt set forth hercin.

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~0~7846 ¦l Other materials susccptible to the practice hereof include: acrylonitrile, methacrylonitrilc, 2-chloroacrylonitrile, lland allyl esters, such as the bisallyl biscar~onate ester of ¦l~diethylene glycol.
¦I Copolymers of the aforementioned unsaturated materials ¦
may be obtained. ~mong the copolymers which may be prepared in accordance herewith are: copolymers of butadiene, acryloni~rile, ¦¦vinyl acetate, vinylidene chloride, methyl acrylate, and ¦!divinylbenzene with styrene, and one another. Copolymcrs of butadiene with styrene, butadiene with acrylonitrile, ac~ylic acid with acrylamide, vinyl acetate ~ith vinylidene.chloride, styrene with methyl acrylate, and styrene with divinylbenzent:, are examples of specific copolymers which may be prcpared pursuant to this invention. Terpolymers prepared in accordance herewith are ~often of special utility, such as those derived from butadiene, !acrylonitrile, styrene mixtures and other mixtures wherein vinyl ¦lacetate, or methyl methacrylate may be components of the terpolymerl.
Il Preferred monomer systems of the present invention are ¦jthose contailling water soluhle monomers such as acrylamide, diaccto lc lacrylamide, acrylic acid, methacrylic acid; monomers such as ¦ diethylaminoethyl methacrylate, dimethylaminoethyl mcthacrylate or!
jdimethylaminoethyl acrylate and their derivations such as for example amine and quaternary ammonium compounds; vinyl monomcr systems containing unsaturated maleate and fumarate polyesters; monomers jcontaining acrylate or methacrylate unsaturation either separately ¦or in combination with comonomers such as styrene, methyl methacryl~te ¦lacrylonitrile, vinyl acetate or vinylidene chloride; and latex forming systems containing butadiene either alone or in combination rith copolymerizable vinyl monomcrs such as styrene, acrylonitrile, vinyl acetate or vinylidene chloride.

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- - . ,. : -.-~ ~1)978~6 The initiators of the invention have differenteffectiveness in different polymerization media, which may be aqueous or organic in nature. Most of the initiators are soluble in organic media. However, in aqueous media the selection of the best initiator is best determined experi-mentally. In general the least substituted aromatic diacetic acid initiator is water soluble. As groups are substituted on the molecules, initiators may lose water solubility. For example, p-toluidene diacet1c acid was found soluble in aqueous solutions whereas p- (n-octyl) anilinediacetic acid was not found soluble in aqueous media.
The ethylenically unsaturated monomers which are polymerizable according to the method of the invention should not contain any group with which all the acid groups of the initiator will preferentially react chemically. For example, monomer substituents such as for example, amines, isocyanate or vinyl epoxy groups are highly reactive with the acid groups of the initiator. Such substituents, i present, will derivatise the acid groups to amides or esters. While amine substituents may cause derivation reaction~ which may be reversible by acidification, substituents ~uch as isocyanate or vinyl epoxy groups, will cause irreversible reactions which will permanently diminish or terminate the ability of the initiators to generate free radicals. By the phrase "any group with which all the acid groups of the initiator will preferentially react chemically" is therefore meant any highly reactive groups which will non-reversibly deriva-tise all the acid groups of the initiator.
As is well known to those skilled in the art, free radical polymerization refers to those polymerization reactions which take place through intermediates having an odd number ; of electrons.

Il ~0~7846 ,ancl, consequently, an unpaired electron. It is these intermediates ¦whieh are generally referred to as free radicals. The free radicalls ¦jare normally cJencrated in one or more of a variety of ways such as by the decomposition of a chemieal initiator added to the ¦Ipolymerizable mixture or by the application of heat or ionizing radiation to the composition. If the free radical is generated in ¦the pxesenee of an ethylenieally unsaturated monomer described abov,e, 'the radical will add to the double bond with the regeneration of another radical. This radical will, in turn, react with another monomer and in the course of the reaction generate another free ¦radical resultinq in growth of the polymer ehaln through the laddition of one ehain to another. Free radical polymerization is ¦cleseribed in detail in, for example, the _ncyclo~edia o~ Pol~mer ¦Iseience and Tec}lnology, Vol. 7, pages 361-431, Interseienee Publishers, 1967, and in the Texthook of l'olymer Scienee, Billmcyer!, ,~Interseienee Publishers, 1962, pages 262-290.
~¦ In addition to growth of the polymer ehaill, several side ¦Ireaetions ean also take plaee during the course of the olymerization reaetion. One of these, identified as ehain transfer refers to the transfer of an atom from a moleeule ~o a ¦Ifree radieal in the reaetion mixture. Depending upon the nature of jthe other material, this ean result in the formation of additional polymer molecules, the formation of braneh chain polymers, or in ermination of the polymerization reaetion on a growing raclieal chain.
¦ Chain transfer agents do not terminate the polymerization eaetion entirely but merely terminate a growin~J chain ancl allow the polymerization to start elsewhere. If premature termination f the growing polymer ehain oeeurs, a reduced molecular weight results and other polymer properties are achieved. It is, for ! -- , 13~4 '~'`t , ~Log7846 this reason, often desirable to include in a free radical polymerization system a chain transfer agent which would funct;on in this manner allowing molecular weight control.
The concentration of the various components utilized in the production of polymer in accordance with the invention may be varied over extremely wide ranges and appears to be not narrowly critical. The concentration of the initiator is dependent on the activity of the initiator used; the type and concentration of other components such as solvent and monomer; and promoters such as heat and light. Although a concentration range of .01% to 2% is economically preferred for optimum monomer conversion, under favorable conditions shown hereafter in the examples, any amounts which are effective may be used, e.g. initiator concentration of as low as 0.006% by weight of monomer system and as high as 9% or more by weight of monomer system may be used successfully.
For example in nonaqueous systems the activity of p-toluidine diacetic acid is far greater than an initiator having an unsubstituted aromatic ring such as aniline diacetic acid, Hence the concentration of a greatly active initiator may be less than those of less active initiators. In general in the presence of air, oxygen or other polymerization inhibitor larger amounts of initiator may be required.
The temperatures used in the practice hereof may vary widely and are only limited by the freezing and boili~g point of the polymerizable system. In aqueous systems the polymerization may be conducted between about 0 and 100C.
Nonaqueous media such as styrene, or isopropyl methacrylate may allow for polymerization temPeratures as high as about 125C. Other nonaqueous media may allow for polymerization ~ .

~ q7~46 temperature of 200C or higher.
The invention does nok exclude the utilization of ~ ~..e~iza'lor. ~-.hl~i~ors, accelerators and molecular weight modifiers. Any of these may be employed if so - 12a -:
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lOq7846 dcsired. Illhibitors may incllJde any ~ree ra~lical scave~ er.
The polymerization process accorcling to ~he invention mayl ¦occur over a ~ide range of pil. The optimum pll of the polymerizablo ¦systcm will bc affec~cd by ~he stability of the mollolncr ancl the ¦solubility and stability of the initiator.
Ii It has also been discovered that the initiators are ¦¦considerably less active when not substantially in the acid form. I
¦! The activity of the initiator and thus the rate ~f polymerization¦
¦llmay therefore be regulated by adjustment of pll. ~s a further advantage, the invention therefore provides for a latent polymerizabl~
Isystem by having the initiators present not in the acid form but as ¦the inactive salt, for example, the inactive sodium salt, or amine¦
salt. Such a latent system may thcn be activated by the simplc adjustment of pll to a point below the neutralization point of the system. The neutralization point is hereby deined as the pll pOill~
of the polymerizable system at which the initiator becomes active due to the presence of acid group. In general the lower the pl; of l~the polymerizable system, the more active the initiator and ; jconversely the higher the pH, the slower the rate of polymerization ¦will be. It should be noted that the neutralization point of the polymerizable system will vary depending on the specific initiator ¦cmployed.
Il A particular advantage of a latent polymerizable system ¦iis the ability to polymerize a liquid polymerizahle system at any ¦Itime in situ merely by the addition of acid to lower the pl~ of the ¦¦system. For example, in oil recovery operations a water solublc monomer mixture of sodium acrylate and acrylamide and an inactive I
salt of an initiator may be introduced into an oil bearinc~ formation las a low viscosity liquid and subsequently polymerized by the iaddition of acid to activate the initiator to produce a highly jviscous polymer solution in situ.
.' l 1~04 I - 13 -, '' 1097846 -- j Tlle invention also ~rovides for a polymerizable syst~m 1icontaining additionally a second frce radical polymcrization j1initiator or catalyst such as a peroxidc systcm to cause postcuring .
The invention is further illustrated by the followin~3 examples in whic1- all parts and percen~acJcs arc by weiyllt unless ¦otherwlse spccified. In the case of the water soluble polymers, ¦the symbol "Ni" represents intrinsic viscosity (i.v.) as measured in dl/g in a 2N sodium chloride solution at ~5.5C.
\rll~ L~ 1 I A solution of 25 grams of ylacial acrylic acid, 75 grams ¦1of acrylamide and ]00 grams ~istilled water was prepared. To ¦ this monomer solution was added a solution of catalyst consisting of 0.2 gram p-toluidene diacetic acid and 2.5 grams NaO11, and 87.5 grams distilled water. This mixture resulted in a very light¦
¦tan colored clear solution. The pll was 4.~, the monomer concen-tration was 20.0~ and the catalyst concentration was 0.20~.
The monomer solution was then poured into a polyethylene bag, flushed with nitrogen for l minute then sealed with tapc. Tl-~sample was placed ir. a dark cabinet for 17 hours at room ¦temperature. A rubber gel had resulted. Isolation of copolymer ¦with a methanol-sodium hydroxide solution showed the conversion of monomers to copolymer to be essentially l00~ complete. The intrinsic viscosity of the copolymcr was 16.6 dl/cJm when measured in 2 N NaCl at 2qC.

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1304 ~ - 14 -r 1097846 ` I
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To illus~rate the wiclc rangc of concclltra~iolls in wllicll tlle initiators are useful in free radical polymerizations, p-toluidine diacetic acid was used to initiate a 20% aqueous acrylamide solution in the presence o air and sunlight at room temperature. The following Table I shows thc results.

T~Ll. 1 Initiator Ni ~, ~!onomer I~xaml?le Conccnl:ration % i.v. ConvcLsioll I
2 4 1.6 dl/g ,99

3 2 2.8 dl/cJ 100

4 1 3.8 dl/g 100 0.5 5.~ cll/(J 100 6 0.16 9.0 dl/y 100 7 0.04 ~ little rcac~ion ~ The results of Examples 2 to 7 also indicate that the ; intrinsic viscosity of the polymer is inverscly proportional to the concentration of the catalyst.
Different initiators were evaluated for their activity ¦ by polymerizing 2 g of acrylamide dissolved in 8 ml of distillcd water. The following Table II indicates thc results. Irnerc the indicated light source is sunlight, tlle samplcs wcre exposed to dlrect sunlight in an open jar at 28C, Whcre the indicated sourcl is laboratory daylight the samples were stored in a closed jar near la window und(- an~ient conditions.

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~-- l l 10"7846 TAB].I II
Concen- Li~ht ~ osure Example Initiator tration Source Light 8 aniline- z~ sunlic~ht 9 minutes diacetic acid 9 toluidine- zoO sunlight 45 seconds diacetic acid p-l~hcnylcnc 0 5~ sunlight ZO minutes diaminetetra-; acetic aci.d 11 2,4-dimethyl- 1.0~ lab. 14 hours ¦ anilinediacetic dayligh~
acid 12 2~4-dimethoxy- 1.0~ lab. 1 hour anilinediacetic daylight acid ¦ All of the examples 8-12 produced polymer in th~
I indicated time period.

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1! ~097846` 1l ~A~ 1 13 To a solution of 2g acrylamidc and 40 mg ~-toluidine diacetic acid in 8g water wcre addccl 2 drops of a 33% sodium hydroxide solu~ion. The resulting pll was 9. Thc solution was cxposcd to sunlight for 80 minutes bu~ failed to ~cl. Thcrcupo pH was adjusted to 4.5 by addition of concentratcd hydrochloric ¦acid and exposure continued. Gelation was complete within 6 Iminutes. Conversion: 97.5%. The intrinsic visc~sity of thc Ipolyacrylamide was l~i = 4.6 dl/g in 2N NaC1 at 25.5C.
l ll ! ~xArlpL~ 14 ¦ To a solution of 2q acrylamide and 8~ water were added ¦20 mg of the sodium salt of p-toluidine diacctic acid. Upon llillumination with a 300 watt visible light source at 12" for ¦¦1 3/4 hours, no gelation occurred. Thereupon, 20 m~ of p-toluenc j sulfonic acid were added. The resulting pll was 3. A clear, I
colorless gel formed after 9 minutes of additional exposure ¦ i indicating the acrylamide had polymerized.
, EX~LE 15 To a solution of 2q acrylamide and 8g water were added 20 mg of the sodium salt of p-toluidine diacetic acid. Upon heating at 60C in the dark for over 4 hours, no polymerization ,occurred. Thereupon, 20 mq of p-toluene sulfonic acid were added.¦

The resulting pl~ was 3. Ileating at 60C in the dar~ was continued. A clear, colorless gel formed in 15 minutes.

E ~ ~LE 16 To a solution of 2g acryl~mide in 4g wa~cr and 49 ; ~ methanol were added 40 mg of the sodium salt of p-n-butylaniline ¦diacetic acid. The sample was illuminatcd for 1 1/2 hours with a ¦

¦ 300 watt visiblc light sourcc a~ a dis~allcc oE 12". i~o IlJL:dmc 1104 ~ 11 17 .. Il ' .............................. i , .

10~7846 ~!1 olYnleri~atiotl occurred. 'l'hel:eupon, ~0 sny p-~oluene sul~onie acid were added. Th~ resulting pll was 3. Fur~her illumination for ~ minutes resultcd in a eloudy, whi~e gel containin~ ¦
polyacrylamide.
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¦ ~XAMPLF 17 To 2g of a polyoxypropylcnc bisphcnol A fumarate resin ~commereially available from ICI-US Inc. as ATLAC-382-05 ¦unsaturated polyester resin) was added 0.3 ml of a solution of dimethyl~minocthylmethacrylate containinc3 10 mq of p-n-butylaniline diaeetie aeid. The acid is presumably present as the amine salt. Tho sample was illuminated ~or 1 1/4 hours with a 30Q watt visible light source at a distanee of 12". A very-sliqht amount of polymerization oecurred. After addition of 300 mg I Ip-toluene sulfonie aeid and further illumination, a hard cure oeeurred within 4 minutes.

To 2g of polyoxypropylene bisph~nol ~ fumarat~ resin ~as added 0.3 ml of a solution of dimethylaminoethylaerylate ¦¦eontaining 10 mq of p-n-butylaniline diaeetie aeid. The sample ,was heated at 60 overnight in the dark. No eure oeeurred. After ¦addition of 200 mg p-toluene sulfonic acid, the sample cured ~overnight to a hard solid.

¦ EX~LE 19 ¦
To lg polyoxypropylene bisphenol A furmarate resin was jadded 50 mg of dimethyl-p-toluidine diacetate. The sample was illuminated for one llour usillg a 300 watt visi~le light source at a distance of 12". No cure occurred. Thereupon, 50 mg p-tolucne sulfonic acid were added, illumination continued, and completo cure occurred witllin 6 minutcs.

* Reg. ~M _ ;8 _ ¦

~- ; ''` 1097846 ¦ EYl~MPL~ 20 Prcparation of m-phcnylenediaminc tet.l^dacet:ic acid Into a three-neck, round bottom (r.b) flask, equipped with glass stirrer, reflux condenser, thcrmomcter, and addition Ifunnel were placed 32.4g (0.3M) m-phenylenediamine dissolved in ¦300 ml water and 203.1g sodium chloroacetate in 300 ml water, and ¦10 drops of a mixed acid/base indicator. The solution was heatcd ¦to reflux and a solution of 48g sodiurn hydroxide in 150 ml water added dro~)wise so as to maintain the pll betwcen 5 and 8. Re~c~ioll;
was completed within 65 minutes. The reaction mixturc was cooled and acidified to pH 1 with 120 ml conc. hydrochloric acid. The formed precipitatc was filtered, washcd with watcr al: pH ~ nd vacuum dried below 40C. Recovered 49.4g gray solids (mp = 188C,¦
;~N = 7.6).

Prepar~tion o~ p-(n-butyl)aniline diacetic acid Into a three-neck r.b. flask, equipped with glass stirrer, reflux condenser, thermometer, and addition funnel were placed 29.9g (0.2M) p-n-butylaniline; 46.6g (0.4M) sodium chloroacetate ¦ dissolved in a solution of 200 ml water and 45 ml dioxane and 10 ¦ drops of a mixed acid/base indicator. The solution was heated to reflux and a solutlon of 16g sodium hydro;cide in 64 ml water was added dropwise so as to maintain the pll between 5 and 3 as shown ~¦by the indicator. Reaction was completed within 4 hours. The ! reaction mixture upon dilution with 500 ml water and cooling was acidified with 43 ml conc. hydrochloric acid. The f~rmed precipitate was filtered and washed twice with 200 ml of water at p~l 1.3 and dried under vacuum at 40C. Yield: 41.2g beige solids (%N = 4.9.) HJL dmc l 1304 I _ 19 _ Il . ' .

1097846 1, I~XAMPLE 2 2 IPreparation of dimcthyl-~-toluidinediaccta~c I
¦ Into a three-neck r.b. flask, fitted with stirring assembly, therrnometer, reflux condenser, and a dropping funncl wcre placed 10.7g (0.1~) p-toluidine, 21.7g (0.2~
methylchloroacetate, 50 ml watcr, and 80 ml dioxane. The solution was heated to rcflux and 32g of an aqueous solution containing 8g (0.2~1) sodium hydroxide was added dropwise so as to I
maintain the charge at a ncutral pll. ~ddition was comylctcd ¦Iwithin 1 1/2 hours. The flask was cooled to 5C, and tll~ product ¦
was poured into a 4 1. beaker. Upon addition of 3 1. of water, a ppt. formed which was discarded. I.xtraction o~ the a-lueous phase with chloroform and stripping the extract ~ave 24.6g of ¦light-yellow solid.

~ ~XAMPLE 23 ¦Preparation of p-mcthylenediallilinctctraacc~ic acicl ¦ Into a three-neck r.b. flask, equipped with glass ¦stirrer, reflux condenser, thermometer, and addition funnel were placed 29.7~ p-methylenedianiline tO.15M~, and 87.3g sodium chloroacetate (0.75~1) dissolved in 300 ml distille~ wa~er and 10 ¦¦drops of a mixed acid/base indicator. The solution was heated ¦~to reflux and 150 ml of an aqueous solution containing ~a~ (1.2M) sodium hydroxide added flropwise at a rate so as to maintain the ~pH at 6. Reaction was complete within 2 1/2 hours. The reaction mixture was poured into a 4 1. beakcr filled with ice water. To Ithis solution were added slowly and with constant very rapid ; Istirring 60 ml concentrated hydrochloric acid solutioll. Fillally, JL:dmc I
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'`` 1097846`

~IIC ~ was broucJIlt to 1.5 wi~!l lN hydrocllloric acid solutio~
precipitate formed. The precipitate ~las filtered and washed twice ¦
¦with 3 l/2 1. and l l/2 1. of cold water whose pll was adjusted to 2. The precipitate was filtered and dried under vacuum, taking care not to heat the precipitate above 35C. ~ white powder ¦weighing 62g was obtained. Thc product had to be refrlgerated in ¦order to reduce its rate of decomposition. (~ = G.04, ~ Cl = o.l5!, water = 9 4~ ~ sulfated ash = 0.20~. If the product was kept refrigerated in the dark and remained stable for more than one month.

Preparation of p-toluidinc diacotic acid l . , Into a three-neck, r.b. flask, equippcd with glass stirrcr, rcflux conden:cr, thcrmome~cr, and addi~ion funllel wcre placed 53.5g p-toluidine (0.5 M), and 116.5(J sodium chloroacctatc dissolved in a solution of 200 ml water and 10 drops of a mixed acid/base indicator. The solution was heated to re~lux and a solution of 40g sodium hydroxide in 120 ml water added dropwise so as to maintain the pll bc~w~cn 5 and 8. l~eaction was complete within 80 minutes. The reaction mixture upon coolin~ was ¦acidified with 15 ml of conc. hydrochloric acid solution. Thc ¦¦formed precipitate was filtered, washed with water at pll 2, and ¦Ivacuum dried below 40C. Yield: 86g beige solids. (%N = 6Ø) ¦¦ EX~MPL~ 25 ¦Preparation of the sodium salt of p- (n-but~l)aniline diacetic acid ¦
¦1 Into a three-neck r.b. flask, equipped with glass ¦Istirrer, reflux condenser, thernlometcr and addition funnel were placed 29.9g (0.2 M) p-n-butylaniline; 46.6~ (0.4 M) sodium chloroacetate dissolved in a solution of 200 ml water and 45 ml IIJL dmc _ l _ :

--` 1097846- 1 dioxane and 10 drops of a mixc~ acid/base indicator. The solution ¦was heated to reflux and a solution of 16~ sodium hyclroxide in 16~ ml water was a~ded dropwise so as to maintain the p~l between S and 8 as shown by the indicator. Reaction was completed within ,4 hours. The reaction mixture was stripped to dryness to give 50g¦
of the sodium salt of p-(n-butyl)aniline cliacetie acid. Some sodium chloride impurity may be present in tl-c product.

To a solution eontaining 2 gram~ of acrylamide~ 2.0 gralr,s of sodium ehloride, 40 mg p-toluidine diaeetic acid were added 2 drops of a 33~ sodium hydroxide solution. ~Ihe resulting pll was 9 Tlle solution was exposed to sunligllt for ~0 ;ninutes but failecl to gel, Thereu~)on, yll was a~justed to 9.5 by addition of eoncentrated ¦hydroehloric aei~ and exposure eontinued. Gelation was complete ¦within 6 minutes. Conversion was 97.56. The molecular weight Iwas higller than that of a eontrol sample, with no salt added, Ij as eviclenced by its solution viscosity.
I ~XAMPL~ 27 To a solution o 2 g aerylamide in 7.95 g of water were added 0.05 ec of a solution eontaininc~ 250 mg of p-toluidine diacetic aei~ in 100 ml of water. l'he catalyst concentration base~ on monomer weight was 0. 006o~ The sample was degassed in a ¦viai and kept und~r vaeuum. ~fter illuminatioll with a 300 watt ¦visible light souree at 12" for 25 minutes gelation was observed.
¦A eontrol sample similarily exposed did nGt gel. Conversion 60~.
The intrinsie viseosity of the polyaerylamide was Ni = 19.4 dl/c~
I in 2N NaCl at 25.5C.

1304 1~ - 22 -.

~ ,

Claims (10)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1, A method of polymerizing a polymeric system containing one or more ethylenically unsaturated compounds susceptible to free radical polymerization which comprises initiating polymerization by contacting the system with an effective amount of dissolved initiating compound selected from the group consisting of p-methylenedianiline tetraacetic acid m-phenylenediamine tetraacetic acid anilinediacetic acid p-toluidinediacetic acid p- (n-butyl)anilinediacetic acid 2,4-dimethylanilinediacetic acid 2,4-diethylanilinediacetic acid [(2,4-dimethoxyphenyl)imino]diacetic acid [(4-hydroxyphenyl)imino]diacetic acid [(4-chlorophenyl)imino]diacetic acid [(1,1'-biphenyl)-4-ylimin] diacetic acid (2-naphthylimino)diacetic acid (1-naphthylimino)diacetic acid [(4-phenylmethylphenyl)imino]diacetic acid [(4-methoxyphenyl)imino]diacetic acid.

2. A method as claimed in Claim 1 wherein the system is contacted by a salt of the initiating compound which salt upon acidification will yield said compound and where the system is subsequently acidified.

3. A method as claimed in Claim 2 wherein said acidification is effected by pH adjustment of the system to within a range of 1-9.

4. A method as claimed in Claim 2 wherein the salt is an alkaline metal salt.

5. A method as claimed in Claim 2 wherein the salt is an amine salt.

6. A method as claimed in Claim 2 wherein the ethylenically unsaturated monomers are acrylamine and acrylic acid and wherein the pH is adjusted to a range of 3 to 5.

7. A method as claimed in Claim 1 wherein the ethylenically unsaturated compounds are selected from class consisting of acrylic acid, acrylamide, methacrylic acid, di-ethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, dimethylaminoethyl acrylate, maleate or fumarate polyester, butadiene, styrene, methyl methacrylate, acrylonitrile, vinyl acetate and vinylidene chloride.

8, A polymerizable system susceptible to free radical polymerization which comprises one or more ethylenically unsaturated compounds and an initiator comprising a dissolved compound selected from the group consisting of p-methylenedianiline tetraacetic acid m-phenylenediamine tetraacetic acid anilinediacetic acid p-toluidinediacetic acid p- (n-butyl)anilinediacetic acid 2,4-dimethylanilinediacetic acid 2,4-diethylanilinediacetic acid [(2,4-dimethoxyphenyl)imino]diacetic acid [(4-hydroxyphenyl)imino]diacetic acid [(4-chlorophenyl)imino]diacetic acid [(1,1'-biphenyl)-4-ylimino]diacetic acid (2-naphthylimino)diacetic acid (1-naphthylimino)diacetic acid [(4-phenylmethylphenyl)imino]diacetic acid [(4-methoxyphenyl)imino]diacetic acid,

9. A polymerizable monomer system as claimed in Claim 8 wherein the initiating material comprises a salt which upon acidification will yield the said initiating com-pound.

10. A polymerizable system as claimed in Claim 8 wherein the ethylenically unsaturated compounds are selected from class consisting of acrylic acid, methacrylic acid, diethylaminoethyl methacrylate, dimethylaminoethyl meth-acrylate, dimethylaminoethyl acrylate, butadiene, styrene, methyl methacrylate, acrylonitrile, vinyl acetate and vinyl-idene chloride.