CA2173824A1 - Ethylenediaminetriacetic acid and salts thereof as chelating agents in pulp bleaching - Google Patents
Ethylenediaminetriacetic acid and salts thereof as chelating agents in pulp bleachingInfo
- Publication number
- CA2173824A1 CA2173824A1 CA002173824A CA2173824A CA2173824A1 CA 2173824 A1 CA2173824 A1 CA 2173824A1 CA 002173824 A CA002173824 A CA 002173824A CA 2173824 A CA2173824 A CA 2173824A CA 2173824 A1 CA2173824 A1 CA 2173824A1
- Authority
- CA
- Canada
- Prior art keywords
- mls
- pulp
- salt
- salts
- ethylenediaminetriacetic acid
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
- D21C9/10—Bleaching ; Apparatus therefor
- D21C9/16—Bleaching ; Apparatus therefor with per compounds
- D21C9/163—Bleaching ; Apparatus therefor with per compounds with peroxides
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
- D21C9/10—Bleaching ; Apparatus therefor
- D21C9/1026—Other features in bleaching processes
- D21C9/1042—Use of chelating agents
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Wood Science & Technology (AREA)
- Paper (AREA)
- Detergent Compositions (AREA)
Abstract
A process for metal ion chelation in pulps. Extraction and removal of detrimental metal ions, preferentially manganese, iron and copper, prior to delignification and bleaching is carried out on pulp, preferably kraft pulp, using ethylenediaminetriacetic acid or ethylenediaminetriacetic acid salts as the chelating agent. Suitable salts include alkaline earth metal, alkali metal, ammonium and amine.
Description
_, ET~IYIE~EDL~ CETIC .~C~ D SALTS T~:REOF ~S
C~:LAT~G ~GE~ 1~ PULP BLEAC~ING
Hydrogen peroxide solutions are cormnonly used for bl~hina cellulosic materials,including paper pulps, colton, linen, jute, etc. However, the peroxide should be stabilized - to prevent prc~LLulc depletion thereof, in view of the dele~.erious presence of metal ions such as iron, m~no~nl~se and copper. Conventionally, sodiurn silicate has been used as a peroxide bleach stabilizer, but tends to form insoluble silicates which can be deposited onto the fibers being ble~rhr~, as well as onto the ~dLua.
Similarly, prior to bl.o~r-hina of pulps, a p~ Luent wi~h a ~h~tino agent is a standard operation in order to control the metaL profile of ~he pulp. Chelant pre-trP~rment is a key factor in achieving feasible brighm~ss levels and viscosi~ies upon ble~rhinal~liY"i~ ;onwithperoxide. DecomposiionofperoxideunderaL~lineconditions is greatly inrlllPnreli by the pl~sence of c_r~ain iuolg~ic coLu~ounds which behave as peroxide de~o~ poaiLion catalysls. Transition metal ions, such as m~ng~n~se, iron and copper are e~amples of such catalysrs, and thus should be removed prior to ble~hing. Such delet.erious transition me~.al ions can be se~uei,~clcd by the chelati~g agent and are - snbsea,llently washed out of the sys~em in a ~ 3e~ r washing step.
~- The bl~rhing process with peroxide ~,lsually takes place between a pH of 10 and 11 and a te~.d~u c of 71-77C. Under these alkaLine conditions, the following reaction ocrurs:
H7Q + OH---~ OOH- + H~O
The p~ y~O~yl ion (OOH-) created is what p~,~r~ ls the ble~rhing However, if transition metals are present, the following reaction tal~es place:
-~I, H~O -~> ~f~ - HO- + HO-The radicals created enhance the decomposition process. ~r~n~nPse is the metal of most conce.~n when peroxide is the bl~o~rhin~ agent used.
W~en hydro-sulfite is the pleÇ~ d bko~rhinc agem, the metal of most concern is iron. Hydro-sulfite bleaches pulp by a reduction reaction with the Cl~u~ 'ul~ in the pulp.
If iron is present, however, the hydro-sulfite will reduce the iron before the chromofors, hence a larger amount of bleach is needed.
Basta er al., "RP~llrino Levels of AOX - Part 3, Lowering of '~appa No. Prior ~o C10~ Blo~rhing ', pgs. ~3-33, discloses thatpre-trea~nent with ethylPn~ofii~mi~lrirl, aacetic acid (EDTA) at a pH of be~een ~ and 7 snbsr~nt~ y i~ ov~s delig,~iIyi~sz and brightPninG
action of hy~llugen peroxide on oxygen pre~P~ignifiPd softwood kraf;t pulD. EDTA performed better in this regard than other ch~o!~ring agents tested, narne.y, DTPA, TRILON ES9910 and DEQUEST ~060S. Similarly, U.S. Palent No. 4,732,6~0 ~iccloses the silicate-free ble~rhing of wood pulp by the combination of a plc~caLllle~,~ of the pulp with a poly~mil~n~ ~d~u~ylic acid or salt such as ethylen~o~ mi,~(r~, dacetic acid, followed by a ble~rhing with a peroxide soluùon togerher with stabili~ing co~ o~
Ethylen~o~ mil,r~idco~ic acid (ED3A) and irs salts (such as ED3ANa^,) have applications in the field of che1~ring chPmi~rry, and may be used as a star~ing material in the plc~Lduon of strong chP~ting polyrners, oil soluble chelants, suRac~nts and others.
Convemirm~l routes for the syn~hesis of ethyi~ ",i,~ ,iacetic acid were achieved via i~s N-benzyl dL.ivdLivc, which was s~lbseqllPntiy hydrolyzed in ~Ik~line solutions to ED3A~a, thus avoiding cy~ rion to ils 2-o~o-1,4 pi~e.,.,",~;~ci;r acid (3KP) de.ivdLivc. One e~ample of the synthesi~s of e~hy3PnP~i~minP-N,N,N'-~riacotic acid is ~i~r~ospd in Chemical -~lbst~acts 1~. Vol. 71, pave 451, no. 18369c, 1969. nlere it is suted that e~nyle~o~i~min~o reacts with ClH~CCO~H in a 1:3 molar ratio in basic solution at 10C for ~ l hours to form a mi~ture from which ethylen~o~i~min~-N,N,N'-triacetic acid can be se:~d-ed by comple,~ing the same with Co(III). The resulting cobalt comple~ces can be isolated through ion eYrh~noe.
U.S. Patent No. 5,250,728, the disclosure of which is hereby incorporated by .cr~.en~e, discloses a simple process for the synthesis of ED3A or its sals in high yield.
Specifically, a salt of N,~'~thylenP~ min~i~r~ir, acid (ED2AH1~ is con~lenced with stoichiometric amouns, preferably sllght molar eYrossos of, formaldehyde, at ~ eld~Lll~
belween 0~ alld 110C, preferably 0 to 6~C and pH's oreater than /.0 to form a stable 5-l O membered rino intermediate. The addition of a cyanide source, such as gaseous or liquid hydrogen cyanide, aqueous solutions of hydrogen cyanide or ~Ikali melal cyanide, in stoichiome~ric amounts or in a sliavhl molar e~cess, across this cyclic materiai al temperatures between 0 and 110C, p~ dbly between 0 and 6~aC, ~orms elhylen~o~ min~ N,N'-diace~dc acid-N'-cyanomethyl or salts thereof (mononi~rile-diacid). The nitrile in aqueous solutions may be spon~aneously cyclized in the pl~se.lce of less than 3.0 moies base: mole ED2AH7, the base inl~in~ino alkali mer~l or alkaline ea~lh meral hydroxides, to form 2-oxo-1,~piper~7ino~ etir acid (3'i~P) or salts thereof, which is the desired cyclic inrlo~m~ n?~
In the pl~,se.lce of e~cess base, salts of ED3A are formed in excellent yield and purity. This pa~ent also ~i~r'!osos an ~Itr~ rl,~l ;v~ embodiment in which the star~ao material is ED2AH,Xo, where X is a base cation, e.g., an ~Ik~li or ~Ik~lin~ earth metal, a is 1 to ~, and b is 0 to 1 in aqueous solutions. The reaction mi~ure also can be ~ri~tifi~od to ensure complet.e form;ation of carbu~y~ yl-2-u~oyi~ e (the la~am) prior to tne reaction.
Fornaldehyde is added, ~ssenr;~lly resulting in the hydlu~y~e~yl de.iv~ivc. Upon the addition of a cyanide source, 1~yd~olllcl11yl~1JuAyll~ctllyl-3-ketopiye,~llle (mononi~rile monoacid) or a salt chereof is formed. In plac9 of CH,O and a cyanide source, HOCH,C~, which is the reac ion product of form"ldPhyde and cyanide, may also be employed in this method. Upon the addition of any suitable base or acid, this material may be hydrolyzed to 3KP. The addition of a base will open ~his ring ~llu~lu e to form the salt of ED3A.
In view of this relatively ilew technology, ethylPn~ minPtriacetic acid (ED3A) and its salts now can be readily ~roduced in bulk and high yield. Use of ED3A and ED3A salts as rh~,~tina, agents in pulp ble~rhina would result in a cost~rrc Livc process. Surprisingly, the il'VCll~UI~ of the present LUVc;~u~ll nave found that ED3A and ED3A salts actually enh~nre brightne~s and e~ual or ùu~e.lu.lL. EDT~ in such applicatio~s, no,wi~ding the presence of only three carboxylate groups in ED3A as coLu~ d to four in EDTA.
The problems of tne prior art have been uv~.co~e by the insran~ invemion, which provides a process ~or metal ion chelation in pulps. Ex~action and removal of de~rimenr~l metal ions, plc~czc~l~ially "~n~ r-se~ iron and copper, prior to ~elignifir~rion and ble~rhina is carried out on pulp, preferably k~aft pulp, using ethylenP~ minPtriacetic acid or ethylenP~i~minP~iacetic æid salts as the chPl~tinv- agenn Fi~re 1 is a graph of l~ ~css g~inc of various rhPI~ting agents;
Figure 2 is a oraph of variouc brighme s gains of various chPI~ting agents afterpero~ide ble~rhinv-; and - Figlre 3 is a graph of iron and m~nganP~e removal by various rhPI~ting agents prior to blP^.rhinv 2 i 73824 Sui~aole salts of e~yle~ min~o~i~nori~ acid thal are userul in ~e prse~t Inve~tio~
incluc- alk~ii me~l and aLQL~De ear~ me Is, preferaDiy sodium and po~ss.um. ~nd arnmo~ium a~d am~ne (such as ~iethanol amine and monneth~nol~nnine) salts, which can e~siiy be pre?ared from ED~A acid by c~uve~l~n~i mea~s. For purposes of iUus~ranon. ~he sodium salt will be used, althou,il it should be u~ uod that othe~ s~ts may be empioved WiltlOUI C~ l~a from ~he sp r.~ ~nd scope of the inve~on.
S ep I in t~e ove.-all re criou sc~eme for l~lodu~.iLL, ED,~ is the ~ik~lin,o con~i~nc~r-on of rormaLde_yde w~ N.N'~nyl~ inP n;.conillm ace~le to for;n a 5-membe~ na ~uue.~ ~is(~ uAy~erhYi)imia~zolidine, and is illus~ale~ as follows:
S~ep I
C~kaXo N COOFaXo > ~ ~ ~
N C !~}iaX~7 ~, a = O ~c 1, ~ = I sa ~ COOHaXo Wi.Ce 3--i~ = 2 ~
rne above reaction may ~e car~ie~i OUI iD ~he pl_se~e of ~ ion~l base. Sui~able bases inc.uae alk~i and ~ Sine ea~h me~raL hy~lluAiaes7 pre.;e~ably sodiurn a~d pOs~c~ l~m hydro~ide. Cu~uuuud (I) is the br-~a,ed reac~iol produc~ of EDDANa,~ nd fo.~aide yae, whic~ the is a s;able iuL~.~e~ the ED~A sy~;hes:~s. Cullwuu~d (I) is for;iled easiiy be~ee~ 0~ and 110"C. The Ste~ I re~c~o~ proce_~s auic!~ a lrorms readïiy a~ pH s gre~te- ~ abou~ / 0 Pxre~ the 'R:l~uC. ~ule e~ Lo~ed is abou~ O to 6~'C, most prer;e.~bly 1~ to 60^C, aL~ou~ -~e;llL~ LLLL-S hi~er than 6~'C are ope.-~bLe FormaLdehyde can be used in stoiciior,e~ic amounts, aLtnou~ is plc~è;~e~ tha~ a sli~ ~
molar ce-c~ss be use~, plcf~iably 0 ~ a7a-~.Oa~a. Pre~e.~bly the coLlce3udLion of the formaLdehyde is ~ ~a or less in ac,ueous solu~ion P~ kT~hyde also can be used The se~ond srp in the r~c ion scheme ~s illus~atc~ be.ow:
- Ste~
COOF.aXo CO~Y~XO
h n -- L.C~
N N , _ ~, C30YAaXo C~} oXo (II) !A~ ,r-dlacd G~ uuulld (II) is re~diiy .crme!i ar ~c.,l~es be~ree~t Oc and llOCC rne reac~on should be con m~ ~i at te~De,~rures a~ or beLow d~e boii~ poiDt or ~he soiu~on.
Pre,'e~abiy the rce~on is car,e~ out at L~LU~ LCS ~om abour oa to abou~ 6~'C, most pre~e~bLy aoout 1o tO 60C to e~hanc_ ~e reac~on rate Suir~bLe sourc_s of cy~nide inc.ude ~seous hyd~Ovs;l cya~ide, an aaueous snlrtinr~ or lly~u~c c~rarude, or ~ik~ii meraL
cyanide such a~s sodium cyanide or PVIA~ III c7amde, etr. l~he cyanide m y be used in swicniome~r,c amounrs, aLthou~ sli~nt molar r~r~"~s may be use~ IC,;..Loiy O.~o -2.0~i.
Ste~ ~ Ln the re3c~on se-~ e ~s the ~y~lLvLy~ or ~ a (II) tO dle mon 2~ 73824 _, di_c.d cor;.pound (l~I) (par~ ~ i hydroi~Jzed mo~om~-~e diac.d) a~d i~s s~on~e^us c.c'iza~ou ;o 3'~P. Compourld (IV) forms r~dily in the prese~ce Ol a base suc~ aS ai~Li me~l or aL~l~ne e~r~ me~;l hydro~ides. P efe.~bly the base is ~iaOE~. hfoie r~L~os or <
C~:LAT~G ~GE~ 1~ PULP BLEAC~ING
Hydrogen peroxide solutions are cormnonly used for bl~hina cellulosic materials,including paper pulps, colton, linen, jute, etc. However, the peroxide should be stabilized - to prevent prc~LLulc depletion thereof, in view of the dele~.erious presence of metal ions such as iron, m~no~nl~se and copper. Conventionally, sodiurn silicate has been used as a peroxide bleach stabilizer, but tends to form insoluble silicates which can be deposited onto the fibers being ble~rhr~, as well as onto the ~dLua.
Similarly, prior to bl.o~r-hina of pulps, a p~ Luent wi~h a ~h~tino agent is a standard operation in order to control the metaL profile of ~he pulp. Chelant pre-trP~rment is a key factor in achieving feasible brighm~ss levels and viscosi~ies upon ble~rhinal~liY"i~ ;onwithperoxide. DecomposiionofperoxideunderaL~lineconditions is greatly inrlllPnreli by the pl~sence of c_r~ain iuolg~ic coLu~ounds which behave as peroxide de~o~ poaiLion catalysls. Transition metal ions, such as m~ng~n~se, iron and copper are e~amples of such catalysrs, and thus should be removed prior to ble~hing. Such delet.erious transition me~.al ions can be se~uei,~clcd by the chelati~g agent and are - snbsea,llently washed out of the sys~em in a ~ 3e~ r washing step.
~- The bl~rhing process with peroxide ~,lsually takes place between a pH of 10 and 11 and a te~.d~u c of 71-77C. Under these alkaLine conditions, the following reaction ocrurs:
H7Q + OH---~ OOH- + H~O
The p~ y~O~yl ion (OOH-) created is what p~,~r~ ls the ble~rhing However, if transition metals are present, the following reaction tal~es place:
-~I, H~O -~> ~f~ - HO- + HO-The radicals created enhance the decomposition process. ~r~n~nPse is the metal of most conce.~n when peroxide is the bl~o~rhin~ agent used.
W~en hydro-sulfite is the pleÇ~ d bko~rhinc agem, the metal of most concern is iron. Hydro-sulfite bleaches pulp by a reduction reaction with the Cl~u~ 'ul~ in the pulp.
If iron is present, however, the hydro-sulfite will reduce the iron before the chromofors, hence a larger amount of bleach is needed.
Basta er al., "RP~llrino Levels of AOX - Part 3, Lowering of '~appa No. Prior ~o C10~ Blo~rhing ', pgs. ~3-33, discloses thatpre-trea~nent with ethylPn~ofii~mi~lrirl, aacetic acid (EDTA) at a pH of be~een ~ and 7 snbsr~nt~ y i~ ov~s delig,~iIyi~sz and brightPninG
action of hy~llugen peroxide on oxygen pre~P~ignifiPd softwood kraf;t pulD. EDTA performed better in this regard than other ch~o!~ring agents tested, narne.y, DTPA, TRILON ES9910 and DEQUEST ~060S. Similarly, U.S. Palent No. 4,732,6~0 ~iccloses the silicate-free ble~rhing of wood pulp by the combination of a plc~caLllle~,~ of the pulp with a poly~mil~n~ ~d~u~ylic acid or salt such as ethylen~o~ mi,~(r~, dacetic acid, followed by a ble~rhing with a peroxide soluùon togerher with stabili~ing co~ o~
Ethylen~o~ mil,r~idco~ic acid (ED3A) and irs salts (such as ED3ANa^,) have applications in the field of che1~ring chPmi~rry, and may be used as a star~ing material in the plc~Lduon of strong chP~ting polyrners, oil soluble chelants, suRac~nts and others.
Convemirm~l routes for the syn~hesis of ethyi~ ",i,~ ,iacetic acid were achieved via i~s N-benzyl dL.ivdLivc, which was s~lbseqllPntiy hydrolyzed in ~Ik~line solutions to ED3A~a, thus avoiding cy~ rion to ils 2-o~o-1,4 pi~e.,.,",~;~ci;r acid (3KP) de.ivdLivc. One e~ample of the synthesi~s of e~hy3PnP~i~minP-N,N,N'-~riacotic acid is ~i~r~ospd in Chemical -~lbst~acts 1~. Vol. 71, pave 451, no. 18369c, 1969. nlere it is suted that e~nyle~o~i~min~o reacts with ClH~CCO~H in a 1:3 molar ratio in basic solution at 10C for ~ l hours to form a mi~ture from which ethylen~o~i~min~-N,N,N'-triacetic acid can be se:~d-ed by comple,~ing the same with Co(III). The resulting cobalt comple~ces can be isolated through ion eYrh~noe.
U.S. Patent No. 5,250,728, the disclosure of which is hereby incorporated by .cr~.en~e, discloses a simple process for the synthesis of ED3A or its sals in high yield.
Specifically, a salt of N,~'~thylenP~ min~i~r~ir, acid (ED2AH1~ is con~lenced with stoichiometric amouns, preferably sllght molar eYrossos of, formaldehyde, at ~ eld~Lll~
belween 0~ alld 110C, preferably 0 to 6~C and pH's oreater than /.0 to form a stable 5-l O membered rino intermediate. The addition of a cyanide source, such as gaseous or liquid hydrogen cyanide, aqueous solutions of hydrogen cyanide or ~Ikali melal cyanide, in stoichiome~ric amounts or in a sliavhl molar e~cess, across this cyclic materiai al temperatures between 0 and 110C, p~ dbly between 0 and 6~aC, ~orms elhylen~o~ min~ N,N'-diace~dc acid-N'-cyanomethyl or salts thereof (mononi~rile-diacid). The nitrile in aqueous solutions may be spon~aneously cyclized in the pl~se.lce of less than 3.0 moies base: mole ED2AH7, the base inl~in~ino alkali mer~l or alkaline ea~lh meral hydroxides, to form 2-oxo-1,~piper~7ino~ etir acid (3'i~P) or salts thereof, which is the desired cyclic inrlo~m~ n?~
In the pl~,se.lce of e~cess base, salts of ED3A are formed in excellent yield and purity. This pa~ent also ~i~r'!osos an ~Itr~ rl,~l ;v~ embodiment in which the star~ao material is ED2AH,Xo, where X is a base cation, e.g., an ~Ik~li or ~Ik~lin~ earth metal, a is 1 to ~, and b is 0 to 1 in aqueous solutions. The reaction mi~ure also can be ~ri~tifi~od to ensure complet.e form;ation of carbu~y~ yl-2-u~oyi~ e (the la~am) prior to tne reaction.
Fornaldehyde is added, ~ssenr;~lly resulting in the hydlu~y~e~yl de.iv~ivc. Upon the addition of a cyanide source, 1~yd~olllcl11yl~1JuAyll~ctllyl-3-ketopiye,~llle (mononi~rile monoacid) or a salt chereof is formed. In plac9 of CH,O and a cyanide source, HOCH,C~, which is the reac ion product of form"ldPhyde and cyanide, may also be employed in this method. Upon the addition of any suitable base or acid, this material may be hydrolyzed to 3KP. The addition of a base will open ~his ring ~llu~lu e to form the salt of ED3A.
In view of this relatively ilew technology, ethylPn~ minPtriacetic acid (ED3A) and its salts now can be readily ~roduced in bulk and high yield. Use of ED3A and ED3A salts as rh~,~tina, agents in pulp ble~rhina would result in a cost~rrc Livc process. Surprisingly, the il'VCll~UI~ of the present LUVc;~u~ll nave found that ED3A and ED3A salts actually enh~nre brightne~s and e~ual or ùu~e.lu.lL. EDT~ in such applicatio~s, no,wi~ding the presence of only three carboxylate groups in ED3A as coLu~ d to four in EDTA.
The problems of tne prior art have been uv~.co~e by the insran~ invemion, which provides a process ~or metal ion chelation in pulps. Ex~action and removal of de~rimenr~l metal ions, plc~czc~l~ially "~n~ r-se~ iron and copper, prior to ~elignifir~rion and ble~rhina is carried out on pulp, preferably k~aft pulp, using ethylenP~ minPtriacetic acid or ethylenP~i~minP~iacetic æid salts as the chPl~tinv- agenn Fi~re 1 is a graph of l~ ~css g~inc of various rhPI~ting agents;
Figure 2 is a oraph of variouc brighme s gains of various chPI~ting agents afterpero~ide ble~rhinv-; and - Figlre 3 is a graph of iron and m~nganP~e removal by various rhPI~ting agents prior to blP^.rhinv 2 i 73824 Sui~aole salts of e~yle~ min~o~i~nori~ acid thal are userul in ~e prse~t Inve~tio~
incluc- alk~ii me~l and aLQL~De ear~ me Is, preferaDiy sodium and po~ss.um. ~nd arnmo~ium a~d am~ne (such as ~iethanol amine and monneth~nol~nnine) salts, which can e~siiy be pre?ared from ED~A acid by c~uve~l~n~i mea~s. For purposes of iUus~ranon. ~he sodium salt will be used, althou,il it should be u~ uod that othe~ s~ts may be empioved WiltlOUI C~ l~a from ~he sp r.~ ~nd scope of the inve~on.
S ep I in t~e ove.-all re criou sc~eme for l~lodu~.iLL, ED,~ is the ~ik~lin,o con~i~nc~r-on of rormaLde_yde w~ N.N'~nyl~ inP n;.conillm ace~le to for;n a 5-membe~ na ~uue.~ ~is(~ uAy~erhYi)imia~zolidine, and is illus~ale~ as follows:
S~ep I
C~kaXo N COOFaXo > ~ ~ ~
N C !~}iaX~7 ~, a = O ~c 1, ~ = I sa ~ COOHaXo Wi.Ce 3--i~ = 2 ~
rne above reaction may ~e car~ie~i OUI iD ~he pl_se~e of ~ ion~l base. Sui~able bases inc.uae alk~i and ~ Sine ea~h me~raL hy~lluAiaes7 pre.;e~ably sodiurn a~d pOs~c~ l~m hydro~ide. Cu~uuuud (I) is the br-~a,ed reac~iol produc~ of EDDANa,~ nd fo.~aide yae, whic~ the is a s;able iuL~.~e~ the ED~A sy~;hes:~s. Cullwuu~d (I) is for;iled easiiy be~ee~ 0~ and 110"C. The Ste~ I re~c~o~ proce_~s auic!~ a lrorms readïiy a~ pH s gre~te- ~ abou~ / 0 Pxre~ the 'R:l~uC. ~ule e~ Lo~ed is abou~ O to 6~'C, most prer;e.~bly 1~ to 60^C, aL~ou~ -~e;llL~ LLLL-S hi~er than 6~'C are ope.-~bLe FormaLdehyde can be used in stoiciior,e~ic amounts, aLtnou~ is plc~è;~e~ tha~ a sli~ ~
molar ce-c~ss be use~, plcf~iably 0 ~ a7a-~.Oa~a. Pre~e.~bly the coLlce3udLion of the formaLdehyde is ~ ~a or less in ac,ueous solu~ion P~ kT~hyde also can be used The se~ond srp in the r~c ion scheme ~s illus~atc~ be.ow:
- Ste~
COOF.aXo CO~Y~XO
h n -- L.C~
N N , _ ~, C30YAaXo C~} oXo (II) !A~ ,r-dlacd G~ uuulld (II) is re~diiy .crme!i ar ~c.,l~es be~ree~t Oc and llOCC rne reac~on should be con m~ ~i at te~De,~rures a~ or beLow d~e boii~ poiDt or ~he soiu~on.
Pre,'e~abiy the rce~on is car,e~ out at L~LU~ LCS ~om abour oa to abou~ 6~'C, most pre~e~bLy aoout 1o tO 60C to e~hanc_ ~e reac~on rate Suir~bLe sourc_s of cy~nide inc.ude ~seous hyd~Ovs;l cya~ide, an aaueous snlrtinr~ or lly~u~c c~rarude, or ~ik~ii meraL
cyanide such a~s sodium cyanide or PVIA~ III c7amde, etr. l~he cyanide m y be used in swicniome~r,c amounrs, aLthou~ sli~nt molar r~r~"~s may be use~ IC,;..Loiy O.~o -2.0~i.
Ste~ ~ Ln the re3c~on se-~ e ~s the ~y~lLvLy~ or ~ a (II) tO dle mon 2~ 73824 _, di_c.d cor;.pound (l~I) (par~ ~ i hydroi~Jzed mo~om~-~e diac.d) a~d i~s s~on~e^us c.c'iza~ou ;o 3'~P. Compourld (IV) forms r~dily in the prese~ce Ol a base suc~ aS ai~Li me~l or aL~l~ne e~r~ me~;l hydro~ides. P efe.~bly the base is ~iaOE~. hfoie r~L~os or <
3.0~t base: 1~1 ED~ bul prel~.ably < 2.0 ~1 base: 1~1 ED2.~ are em~Loved.
e. conce ~ Ld~lo"s of base (i.e. ~ 3.û ht base : hl ED~ c~use some di~.lv-,ol ~ ;on~non or ~he d cid mo~oDi~ile and some ED~A (er.hyl~n~ m;,.~.r .daceic ac d) is ^or_ed. es~e~;~Ly ~t -e;~ s > 6~'C. In~cniar, the co~ce_~ncn cr ED"!~ ~s found tO be in diree. ~louoldo~ tO the amount nvf e-~c~ss c usic e~nployed, whe l ~
~ LLJ~ L~Le re~c. ons are co~ v~ and i_h molar ra~ios of base ar-e employe~ 2.0~L
base: l~r E32.~ri~. whic~ may be dLU-l~ULt::l O the ~im~ n~ous hydrolysis or ~ and ais?rorpor~o~ation or ~he mononi~ile~iac;.d ~en rhe mole ra~;io or oase to E3'7.`. is <
2 0, hiC e: e~L,e.~.L-L~ 5 may be use~ so, in Ste~ ammonia is -~imin~r~d 'oe~een an amide ~CUD ~nd aIl imino ~ouc on the same mole~1e Eowe~Je-, ar ~owe~ IL)C:r~LIll-S ( <
6- C) h;~ne~ amounrs of base may be employed (> 2 0~) and hydroi~Jsis or eoll~Luu~d (II) c -n proce_d a~ly ~ E~^-~ wi~out cyr~i~ri~n COC~-a~Yq Ste~ lTT / CCO~a Co ~n > ( ~O
~' C~ ' C~, C~O} aXq ~ CCOli~Xq J
COOEsaxq 7 <
CCC~aXq S~e~ I~i LS -~e hyarol~rsis of ~KP~â~ b~r at ~els- the addiuon or 1 e~uiv~ie~l or c~.usuc, prcre~.abLY â 1 moiar ~-~coss ot c~us;ic. r~is amouu~s ro duu~ ,V ~ 7a Wei~nl ~ce_ss (rr~_) c~.usuc in soLu~ion on a ~0~ ED'~Nâ solu~on. rne soLulion is boiLed unde aunosphe~.c ~l~S~lLc to the des~red c~co;,uauon~ P~c.~u.~lv ~he rc~c:Ion is c~r.e~ ou~ by aLsD~ he ~ l~u~.~L~c from the ~;IlU~ULC m Sz~ ~ ~o the boiL ove~ â pe iod from about ;o mim~T~s to abou~ 6 hours.
S.ep IY
~ c~x < <
.~r () (~
C''CX
C;~l:~,X~, X = base c~ncm CO~X (~) rne r~snlrina soiuions t~rpiciLy g~ve aUyL~ "~ y ,~ ~a, wi~h aL~ul~J~ % _æNa~ L~ i"G as an u~uue~e" ,,ng~~nis c~r.~os;~onds to aDou~ a 9~1~a C_llv~ l W E33~a~, wirh the r~-n~inin~ 6~ or mass e.~ s~L~ as ,~a..
~iriifir~n~n of -~is mass to p~I's < 6.0 to prcduc_ E3-;A~ is no~ possioLe, as cyr'i7~tinn to ~PY.~ wilt e~en~Ly ccc~
rne fore20u~ symheic sc~eme .~suLts iu CO~ ..ai~ 5 tO ED~ ac in e~C. SS of SU%, wirh the residu~ UlO~ lUO~ be~ PNa. to g}ve a taraL mass b~anc~ or vir~alLy IOO~i.
rne reacions are wLe.~aDr to a wide p~ ran~o.
r, 1 ~1, v~y, Ei~ ~A can be pre~a~s USi~2 E3 , as ~he slar;ing m~eriaL. wnere is a base, e.g, an ~Ik~li or alk;Ll~e ear;h me aL, a is I tO 2, and b is 0 w I in aqueous _ solu~iccs rne reac~ion mi~;ure aLso c3n be ac.ciried with acids ha~ing pK~'s ~ess rhan or e~ual -o 3, pr.or o ~ur;mg or a*e- the addi~on of a cJ~ude sourco, to ensure comDie~e formaton of c rbo~,me~,vl~ opi,ue~ e (the lac~am), Formaldehyde LS aaded.
esse~tia!ly resuLt~ng m the h,v~o~yLuedl,vL de.iv~Live. Upon ~he ~ddi~on or a cy~nide sourco, 1~-ya~omerh~v~ buAyll~e!llyL-~-~e~iu~,~e or a salt the-~f is formed, and c~n be isolate~ in gocd yield m cns~illine form by cu~v~.lLionaL me~s afce- cooling the re~c~on mL~ure. ConYe sio~(s ~r_ CUal1LiL~LLiVe. ~ PiZC_ of Cr., O and a c,vanide sourco, ~ OCi ~.C~', whici is the reac~on proauc~ of formaldehyde and c,~ide, may aLso be employed iIl tis methca. Upon the addi~on of any s~u~hie ~ase or ac;.d, this mate.-iaL ma,v be h~,rarolyz~d to ~. rne adaition or a base ( > 2.0 ~ valen~ts bul prefe.~bly ~re~ret ~n or e~ual to ~.0 . .
e~uivr~e~ts wiil open tis rng ~U'1e~, 0O for;n the s^lt of E3-~A. ~'e_ting the re^c~on mi ~ure wiil enhqnre the r~Ee or re~doQ.
lhe ove.~ll re~c~ion scheme LS shown be.ow: -A <
_ c~ - ~ =a CF, ~,~
X ~ ~se ~ C::CY~
~ t~ a~
-ac~
C~CY ;4 <
)~C ~~--r N
F ;4 C:C~, ~3~se ~C~
EDDA can also be allowed to ~orm the lactam (carboxymer~hyl-2-o~co-piperazine) by aci~iifir~tion, and the lactam is reacled with chloro or bromo acetic acid to form ED3A or 3KP.
The chelate plclle~ lPnt ~tr~rtion in acc-jld~ce with the presem invention can be carried out in a pH ra~oe of from about 4 to about 11, preferably 4.5-5. Operable te~e,d~ s are from about room ~U~ C~d~ulc to no higher than 100~C at atrnospheric ple~auLc, preferably about 50C to about 90C. Te;~lp~.dLules as 'nigh as 90C actually il~lL~lUVC the comple~ation of metals witn the rhP~nng agent.
Levels of rhelAtino agent from about 2 to about ~0 pounds per ton of pulp are tvpical in the pulp and paper indus~ry for c~ i~a peroxide bleæhing systems. The actu i amount used will depend upon the level of meTals present; the amount of chPl~tina agent being that amount elræaive for rh~lAring ~llrri~iPIl~ metals in orde- to achieve desired briohmPss and avoid undesirable peroxide deco,~o~i~ion. The metal content of the pulp is typically determined by sampling the pulp and ~let~nining its metal content by alomic adsorption.
Chelares comple~ merAIs on a one-wne molar basis.
Preferably the pulp is plc~ Lcd with ED3A and then washed so that the comple~ed metals are washed out of the system. A le,i~ e Qme of at least thirty minutes is needed at this stage to allow the chelates to comple~ the metals present and subse~quentiy be washed.
However, the chelate can be added to the pulp prior to biPArhino (generally at pH's of 7-9) but withoul subse-quent washing, or can be added dire~tiy to the bl~hing process ~generally pH's of 10-11), ~Ithollah these IllrillO~ are generally less crr~ c.
The efflcie~cy of ethylen~fi;A~ iaceL~ acid was CrJI~ ICd along with EDTANa, and Dl'PANa~ and no chelate in e~trac~on of me~als ~om two types of pulp, namelyt sulfite, mAv~ base 2nd stage unbleached supplied by Wausau Paper, and a mP~hAnir~l pulp, ~spen Stone Ground Wood (SGW). The second part ot the e-Yperiment was carried OUI tO
ascertain whether there was any ~nh~nr~m~nt on brightness in peroxide ble~hing on the pulp in using chelate e~traction.
- Method IJsed for Chelate E~trac~ion Five ~s of oven dried (OD) pulp is weighed up into a 600 ml bea~er with a stirring bar and chelate is added at the rale of 1:1 or 2:1 mole ratio of chelate to total me~al content defined as iron, m~ngan~se and copper (Fe, Mn, Cu).
Distilled waler is added to the ~00 ml mar~, (1% COIlSi~ell~;y pulp). The pH of the e~lraction slurry was 4.5 to ~Ø The sample was stirred for 1/2 hour at room tcuu~cl~luuc and then was filtered throus,h a Buchner funnel lined wilh a ~r4 Whatman filter paper.
The we~ weight or the pulp pad was recorded to be used later in I~COhali-uuu~ to 10~o consistency. This procedure was repeated for all the chelates that where evaluated.
?llethod Used for EIY~ Pero~nde Bl~--hina Ble~rhinv was ca~ried out in zip lock bags in a water balh se~ at 70~ C. for two hours. A bleach li~uor was made up of 2.2 % NaOH as 100 % based on 5 gm OD pulp, 3 %
sodium silicate as 100% on 5 g OD pulp, 1% hydrogen pero~cide as 100% on 5 gm OD pulp, and water was added to make the pulp 10% co~s~lcu~;y. The pH before ble~-hing was 10.5.
The air was squeezed OUI of the bag and in!ser~ed in a water bath for 2 hours. After the two hours in the water bath, the bleached pulp was Il~Ç~ .,d to a 600 ml beaker and the pulp was diluted to 1% c~ y, the sample was mi~ed and the pH was recorded. The pH
was then ad]usred with sulfuric acid mi~ed and filtered, using a Buchner funnel with a ~'4 Whatmarl paper. The filtrare was saved for residual p~.wude titration wilh sodium thiosulfate and starch indicator. The puip pad was pressed be~ween four absorbent pads a~
1000 psi for one minute, then oven dried at 100~C for 1/2 hour. The pad was cooled to room temperalure and five brighmPss readings were taken from both sides and then averaged.
ial ~ulp anahrsis 2nd sta2e unb~ Aspen stone ~ound wood Consistency 36.8% 3.6%
Iron, ppm 12.5 26.1 M~n~n~se, ppm 4.3 62.4 Copper, ppm 0.4 1.3 Stoc}~ solutions used:
EDTA Na4~ 92g @~ 39.5% ac~i~y, diluted to 100 mls (p~ ry solution) then 5 mls of ~rilL~y solution diluted to 100 mls, to be used as the worlcing solution for tne e.~peri~ments. (0.565 mg EDTANa" per ml) DTPA Nas: 1.1865g e~ 41.4% activicy, diluted to 100 ml-s (pli~ry solution) then 5 mls of pl~y solunon diluted to 100 mls, to be used as the wor~ing sollln~m for the eA~i LL~,IlL~. (0.593 mg DTPANa5 per ml) ED3A: 1.0874g ~ 35 % ac~vicy, diluted to 100 mLs (~li~Ly solution) then 5 mls of pLilL~Ly solution diluted tO 100 mls, tO be used as the wor~ing solution for the ~ C~ ill l~ LLI~. (0.544 mg ED3A
per mi) NaOH 2%: 8 gm of S0% diluted to 200 mis. (20.0 mg of NaOH (as 100%) per ml.) HYdL~ 1 Peroxide 3%: 10 mls of 50% pe.vAide diluted to 200 mls. (30.9 mg peroxide as 100% per ml.) Sodium Silicq~e 4.51%: 9.02 gm of sodium silic~te ( l l baume) diluted to 200 mls. (45.1 mg sodium silicate per ml.) E~
EDTAl~a (1:1) mole ratio to total Fe. Mn. Cu Ex~rac~ion:
pulp: 2nd stage (13.6 g as is) 5.0g OD
chelate: 2.65 mls of working solution warer: to 500 mls l 0 Bleaching:
~aOH: 5.5 mls of worl~ng solution Silica~e: 3.33 mls of wor~ing solution Pero~ide: 1.62 mls of wor~ing solution Results:
brighrnPss: 13.5 residual: 0.5% as 100%
gain: 8.0 points over no chelate e,~traction, with bl~rhing -E~Al~IPl.E 2 EDTANa, (2:1) mole ratio to total Fe. Mn. Cu E,l~ua~
pulp: 2nd stage (13.6 g as is) 5.0g OD
chelate: 5.30 mls of W~Jlhillg solution water: to 500 mls Ble~- hinu NaOH: 5.5 mls of worlcing solutio~
Silicate: 3.33 mls of working solution Peroxide: 1.62 mls of working solution ResuLts:
F ~ ~ . 73 . 0 r~sidual: 0.6% as 100%
gaiu: 7.6 points over no chelate ~ ;~n, with bl~rhing E~LE 3 DTPANas (1:1) mole ratio to total Fe. Ivtn. Cu 1 0 E.~lrac~on:
pulp: 2nd s~age (13.6 g as is) 5.0g OD
chelate: 3.2 mls of working solution water: to 500 mls Bl~rhing:
NaOH: 5.5 mls of working solution SiLicate: 3.33 mls of working soLution Peroxide: 1.62 mls of WUlk.i~lg solution Results:
bri~ f ,~: 74.4 residuaL: 0.6% as 100~o gain: 8.9 points over ~o chelate ~ oll, wi~h ble~rhinçr E~AMPLE 4 DTPANa, (2:1) mole ratio to total Fe. ~tn. Cu E.c~cuon:
pulp: 2nd stage (13.6 g as is) 5.0g OD
chelate: 6.4 mls of wor~ing solution water: to 500 mls Ble~hinv NaOH: 5.5 mis of wolkillg solution Silicate: 3.33 mls of wor~V solution Pero~ide: 1.62 n~s of wu~hi~g solution Results:
~,ol,",~cs 73.7 residual: 0. 670 as 100 %
gain: 8.3 pointC over no chelate e~lracuion, with bleaching ED,A (1:1) mole ra~io to tolal Fe. ~[n. Cu E~action:
pulp: ~nd s~age (13.6 g as is) 5.0g OD
chelate: 2.39 mls of wu,l~, s~ ti~-n water. to 500 mls Ble~hing NaOH: 5.5 m~s of w~ i~ solution S~icate: 3.33 n~s of W~ g sollltiQn Pero~ide: 1.62 mls of W~ lg solution Results:
.
brightnPss: 75.1 residual: 0.6~o as 100%
gain: 9.9 points over ~o chelate e~traction, with bleaching EgAMPl.E 6 ED;A (2:1) mole ratio to total Fe. ~ln. Cu Extraction:
pulp: 2nd s~age (13.6 g as is) 5.0g OD
chelate: 4.78 mls of wor~cing solutior water: to 500 mls 1 0 Bleaching:
NaOH: ~.5 mls of working solution Silicale: 3.33 mls of working solution Peroxide: 1.62 mls of wor.cing solution Results:
brighm~ss: 74.3 residual: 0.6% as 100%
gain: 8.9 points over uo chelate eYlT~rrir,n with blea~hino E~AMPI~: 7 Blank. no chelate E~traction:
pulp: 2nd stage (13.6 g as is) 5.0g OD
chelate: none water: to 500 mls 2 1 738~4 BIP~h;ng NaOH: 5.5 mls of working solution Silica~e: 3.33 mls of worlcing solution Pero~ide: 1.62 mls of wor~ing solution Results:
brightn~.c: 65.4 residual: 0.6% as 100a~o-gain: 0 The brighm~ readings are graphed on Figure 1. The use of 2:1 mole ratio of chelate to total me~al (Fe, lvLn, Cu) had no 5ignifi~nt ga ns in brightn~s.~, co~ cd to ~he use of a 1:1 mole ratio. ED;A l~ esa gain was 9.9 points over a no chelate treatment e~traction of pulp, and also showed an increase of l.9 points over EDTANal and 1.0 point increase in brighmpcc over DTPANa5.
The ne.~ se~ of c,~l~c~ lenL~ utilized a hi~her m~ng~nP~e pulp, aspen stone ground wood. The same con-liti-)n~ used in the ~lGviOua e~amples were used, e~ce?t that the %
NaOH was i~. leased to 2.6ra instead of 2.2%, in order to achie~e a higher irutiaL pH for ble~ h ing EDTA ~a (1:1) mole ~atio to total Fe. Mn. Cu E~raction:
pulp: Aspen SGW (137.4 g as is) 5.0g OD
chelate: 14.3 mls of w~"~g solution water: to 500 mis BIP~ hina 2 ~ 73824 ~aOH: 6.5 mls of working solution Silicate: 3.33 mls of working solution Peroxide: 1.62 mls of wor~ing solution Results:
brioh m~ss: 67.8 residual: 0.2 % as 100%
gain: i5 points over no chelate e~raction, without ble~ching - E~AMPLE 9 DTPA ~a (1 1) mole ratio to total Fe. hln. Cu 1 0 E~c~ac~ion:
pulp: Aspen SGW (137.4 g as is) 5.0g OD
chelate: 17.2 mls of working solution water- to 500 mls Ble~t~hina NaOH: 6.5 mls of working solution Silicate: 3.33 mls of wor~ing solution - Peroxide: 1.62 mls of wu~ lg solution Results:
brigh m~cc: 69.2 residual: 0.1% as 100%
gain: 16.8 poims over no chelate e,~ud~ , without ble~rhing E~ IPLE 10 ED,A (1:1) mole ratio to rDtal Fe. ~ln. Cu E,Ytrac~ion:
pulp: Aspen SGW (137.4 g as is) 5.0g OD
chelate: 12.9 mls of wor~ing solution water: to 500 mls BlP~rhina NaOH: 6.5 mls of wu.h~g solution Silicate: 3.33 mls of WO~ g solution Pero~ide: 1.62 mls of W013~illg solution Results:
brighmess: 68.9 residual: 0.1% as lOO~Yo gain: 16 points over no chela~e t:,~u~wn, withou~ blP~hina E~fPI.E 11 ED;A (1.25:1) mole raliO tO total Fe. Mn. Cu E,Y~action:
pulp: As;pen SGW (137.4 g as is) S.Og OD
chelate: 16.1 mls of WUlh~lg solution water: to Sû0 mls BlP~rhina NaOH: 6.5 mls of WUl~, solution Silica~e: 3.33 mls of wull~ g solution Pe,w~ide: 1.62 mLs of w~ g solution Results:
69.0 2~ 73824 -residual: O. l a~a as 100%
gain: 16.5 points over no chelate e~traction, without bleaching E~ E 12 Biank. no chelate e~ractian Exfraction:
pUlp: Aspen SGW (137.4 g as is) 5.0g OD
chelate: 0 water: to ~00 mls Bleaching:
NaOE~: 6.5 mls of worlcing solution Silicate: 3.33 mls of worl~ing solution Peroxide: 1.62 mls of worl~ing solution Results:
brighr~cc: 66.5 residu 1: 0.1% as lOOa~o gain: 13.4 points over no chelate e,~traction, without ble~hing -~ The brighmP~-~ gains are plotted in Figure 2, and the % iron and m~ng~nPse removal ~. .
- is plotted in Figure 3. ED,A u~sed at 1:1 mole ratio to me~als nad a greater briohfn~c~ gain than EDTANa~ (15 poin~s ve-sus 16), and when used at 25% excess, wa~s cu~ aLdble to DTPANa5. ~r;",~ f5e e~ctraction witn ED-,A was greater than 91%, which was fairly cu~ ble to EDTANa1 and DTPANa5 at 9~+ % .
e. conce ~ Ld~lo"s of base (i.e. ~ 3.û ht base : hl ED~ c~use some di~.lv-,ol ~ ;on~non or ~he d cid mo~oDi~ile and some ED~A (er.hyl~n~ m;,.~.r .daceic ac d) is ^or_ed. es~e~;~Ly ~t -e;~ s > 6~'C. In~cniar, the co~ce_~ncn cr ED"!~ ~s found tO be in diree. ~louoldo~ tO the amount nvf e-~c~ss c usic e~nployed, whe l ~
~ LLJ~ L~Le re~c. ons are co~ v~ and i_h molar ra~ios of base ar-e employe~ 2.0~L
base: l~r E32.~ri~. whic~ may be dLU-l~ULt::l O the ~im~ n~ous hydrolysis or ~ and ais?rorpor~o~ation or ~he mononi~ile~iac;.d ~en rhe mole ra~;io or oase to E3'7.`. is <
2 0, hiC e: e~L,e.~.L-L~ 5 may be use~ so, in Ste~ ammonia is -~imin~r~d 'oe~een an amide ~CUD ~nd aIl imino ~ouc on the same mole~1e Eowe~Je-, ar ~owe~ IL)C:r~LIll-S ( <
6- C) h;~ne~ amounrs of base may be employed (> 2 0~) and hydroi~Jsis or eoll~Luu~d (II) c -n proce_d a~ly ~ E~^-~ wi~out cyr~i~ri~n COC~-a~Yq Ste~ lTT / CCO~a Co ~n > ( ~O
~' C~ ' C~, C~O} aXq ~ CCOli~Xq J
COOEsaxq 7 <
CCC~aXq S~e~ I~i LS -~e hyarol~rsis of ~KP~â~ b~r at ~els- the addiuon or 1 e~uiv~ie~l or c~.usuc, prcre~.abLY â 1 moiar ~-~coss ot c~us;ic. r~is amouu~s ro duu~ ,V ~ 7a Wei~nl ~ce_ss (rr~_) c~.usuc in soLu~ion on a ~0~ ED'~Nâ solu~on. rne soLulion is boiLed unde aunosphe~.c ~l~S~lLc to the des~red c~co;,uauon~ P~c.~u.~lv ~he rc~c:Ion is c~r.e~ ou~ by aLsD~ he ~ l~u~.~L~c from the ~;IlU~ULC m Sz~ ~ ~o the boiL ove~ â pe iod from about ;o mim~T~s to abou~ 6 hours.
S.ep IY
~ c~x < <
.~r () (~
C''CX
C;~l:~,X~, X = base c~ncm CO~X (~) rne r~snlrina soiuions t~rpiciLy g~ve aUyL~ "~ y ,~ ~a, wi~h aL~ul~J~ % _æNa~ L~ i"G as an u~uue~e" ,,ng~~nis c~r.~os;~onds to aDou~ a 9~1~a C_llv~ l W E33~a~, wirh the r~-n~inin~ 6~ or mass e.~ s~L~ as ,~a..
~iriifir~n~n of -~is mass to p~I's < 6.0 to prcduc_ E3-;A~ is no~ possioLe, as cyr'i7~tinn to ~PY.~ wilt e~en~Ly ccc~
rne fore20u~ symheic sc~eme .~suLts iu CO~ ..ai~ 5 tO ED~ ac in e~C. SS of SU%, wirh the residu~ UlO~ lUO~ be~ PNa. to g}ve a taraL mass b~anc~ or vir~alLy IOO~i.
rne reacions are wLe.~aDr to a wide p~ ran~o.
r, 1 ~1, v~y, Ei~ ~A can be pre~a~s USi~2 E3 , as ~he slar;ing m~eriaL. wnere is a base, e.g, an ~Ik~li or alk;Ll~e ear;h me aL, a is I tO 2, and b is 0 w I in aqueous _ solu~iccs rne reac~ion mi~;ure aLso c3n be ac.ciried with acids ha~ing pK~'s ~ess rhan or e~ual -o 3, pr.or o ~ur;mg or a*e- the addi~on of a cJ~ude sourco, to ensure comDie~e formaton of c rbo~,me~,vl~ opi,ue~ e (the lac~am), Formaldehyde LS aaded.
esse~tia!ly resuLt~ng m the h,v~o~yLuedl,vL de.iv~Live. Upon ~he ~ddi~on or a cy~nide sourco, 1~-ya~omerh~v~ buAyll~e!llyL-~-~e~iu~,~e or a salt the-~f is formed, and c~n be isolate~ in gocd yield m cns~illine form by cu~v~.lLionaL me~s afce- cooling the re~c~on mL~ure. ConYe sio~(s ~r_ CUal1LiL~LLiVe. ~ PiZC_ of Cr., O and a c,vanide sourco, ~ OCi ~.C~', whici is the reac~on proauc~ of formaldehyde and c,~ide, may aLso be employed iIl tis methca. Upon the addi~on of any s~u~hie ~ase or ac;.d, this mate.-iaL ma,v be h~,rarolyz~d to ~. rne adaition or a base ( > 2.0 ~ valen~ts bul prefe.~bly ~re~ret ~n or e~ual to ~.0 . .
e~uivr~e~ts wiil open tis rng ~U'1e~, 0O for;n the s^lt of E3-~A. ~'e_ting the re^c~on mi ~ure wiil enhqnre the r~Ee or re~doQ.
lhe ove.~ll re~c~ion scheme LS shown be.ow: -A <
_ c~ - ~ =a CF, ~,~
X ~ ~se ~ C::CY~
~ t~ a~
-ac~
C~CY ;4 <
)~C ~~--r N
F ;4 C:C~, ~3~se ~C~
EDDA can also be allowed to ~orm the lactam (carboxymer~hyl-2-o~co-piperazine) by aci~iifir~tion, and the lactam is reacled with chloro or bromo acetic acid to form ED3A or 3KP.
The chelate plclle~ lPnt ~tr~rtion in acc-jld~ce with the presem invention can be carried out in a pH ra~oe of from about 4 to about 11, preferably 4.5-5. Operable te~e,d~ s are from about room ~U~ C~d~ulc to no higher than 100~C at atrnospheric ple~auLc, preferably about 50C to about 90C. Te;~lp~.dLules as 'nigh as 90C actually il~lL~lUVC the comple~ation of metals witn the rhP~nng agent.
Levels of rhelAtino agent from about 2 to about ~0 pounds per ton of pulp are tvpical in the pulp and paper indus~ry for c~ i~a peroxide bleæhing systems. The actu i amount used will depend upon the level of meTals present; the amount of chPl~tina agent being that amount elræaive for rh~lAring ~llrri~iPIl~ metals in orde- to achieve desired briohmPss and avoid undesirable peroxide deco,~o~i~ion. The metal content of the pulp is typically determined by sampling the pulp and ~let~nining its metal content by alomic adsorption.
Chelares comple~ merAIs on a one-wne molar basis.
Preferably the pulp is plc~ Lcd with ED3A and then washed so that the comple~ed metals are washed out of the system. A le,i~ e Qme of at least thirty minutes is needed at this stage to allow the chelates to comple~ the metals present and subse~quentiy be washed.
However, the chelate can be added to the pulp prior to biPArhino (generally at pH's of 7-9) but withoul subse-quent washing, or can be added dire~tiy to the bl~hing process ~generally pH's of 10-11), ~Ithollah these IllrillO~ are generally less crr~ c.
The efflcie~cy of ethylen~fi;A~ iaceL~ acid was CrJI~ ICd along with EDTANa, and Dl'PANa~ and no chelate in e~trac~on of me~als ~om two types of pulp, namelyt sulfite, mAv~ base 2nd stage unbleached supplied by Wausau Paper, and a mP~hAnir~l pulp, ~spen Stone Ground Wood (SGW). The second part ot the e-Yperiment was carried OUI tO
ascertain whether there was any ~nh~nr~m~nt on brightness in peroxide ble~hing on the pulp in using chelate e~traction.
- Method IJsed for Chelate E~trac~ion Five ~s of oven dried (OD) pulp is weighed up into a 600 ml bea~er with a stirring bar and chelate is added at the rale of 1:1 or 2:1 mole ratio of chelate to total me~al content defined as iron, m~ngan~se and copper (Fe, Mn, Cu).
Distilled waler is added to the ~00 ml mar~, (1% COIlSi~ell~;y pulp). The pH of the e~lraction slurry was 4.5 to ~Ø The sample was stirred for 1/2 hour at room tcuu~cl~luuc and then was filtered throus,h a Buchner funnel lined wilh a ~r4 Whatman filter paper.
The we~ weight or the pulp pad was recorded to be used later in I~COhali-uuu~ to 10~o consistency. This procedure was repeated for all the chelates that where evaluated.
?llethod Used for EIY~ Pero~nde Bl~--hina Ble~rhinv was ca~ried out in zip lock bags in a water balh se~ at 70~ C. for two hours. A bleach li~uor was made up of 2.2 % NaOH as 100 % based on 5 gm OD pulp, 3 %
sodium silicate as 100% on 5 g OD pulp, 1% hydrogen pero~cide as 100% on 5 gm OD pulp, and water was added to make the pulp 10% co~s~lcu~;y. The pH before ble~-hing was 10.5.
The air was squeezed OUI of the bag and in!ser~ed in a water bath for 2 hours. After the two hours in the water bath, the bleached pulp was Il~Ç~ .,d to a 600 ml beaker and the pulp was diluted to 1% c~ y, the sample was mi~ed and the pH was recorded. The pH
was then ad]usred with sulfuric acid mi~ed and filtered, using a Buchner funnel with a ~'4 Whatmarl paper. The filtrare was saved for residual p~.wude titration wilh sodium thiosulfate and starch indicator. The puip pad was pressed be~ween four absorbent pads a~
1000 psi for one minute, then oven dried at 100~C for 1/2 hour. The pad was cooled to room temperalure and five brighmPss readings were taken from both sides and then averaged.
ial ~ulp anahrsis 2nd sta2e unb~ Aspen stone ~ound wood Consistency 36.8% 3.6%
Iron, ppm 12.5 26.1 M~n~n~se, ppm 4.3 62.4 Copper, ppm 0.4 1.3 Stoc}~ solutions used:
EDTA Na4~ 92g @~ 39.5% ac~i~y, diluted to 100 mls (p~ ry solution) then 5 mls of ~rilL~y solution diluted to 100 mls, to be used as the worlcing solution for tne e.~peri~ments. (0.565 mg EDTANa" per ml) DTPA Nas: 1.1865g e~ 41.4% activicy, diluted to 100 ml-s (pli~ry solution) then 5 mls of pl~y solunon diluted to 100 mls, to be used as the wor~ing sollln~m for the eA~i LL~,IlL~. (0.593 mg DTPANa5 per ml) ED3A: 1.0874g ~ 35 % ac~vicy, diluted to 100 mLs (~li~Ly solution) then 5 mls of pLilL~Ly solution diluted tO 100 mls, tO be used as the wor~ing solution for the ~ C~ ill l~ LLI~. (0.544 mg ED3A
per mi) NaOH 2%: 8 gm of S0% diluted to 200 mis. (20.0 mg of NaOH (as 100%) per ml.) HYdL~ 1 Peroxide 3%: 10 mls of 50% pe.vAide diluted to 200 mls. (30.9 mg peroxide as 100% per ml.) Sodium Silicq~e 4.51%: 9.02 gm of sodium silic~te ( l l baume) diluted to 200 mls. (45.1 mg sodium silicate per ml.) E~
EDTAl~a (1:1) mole ratio to total Fe. Mn. Cu Ex~rac~ion:
pulp: 2nd stage (13.6 g as is) 5.0g OD
chelate: 2.65 mls of working solution warer: to 500 mls l 0 Bleaching:
~aOH: 5.5 mls of worl~ng solution Silica~e: 3.33 mls of wor~ing solution Pero~ide: 1.62 mls of wor~ing solution Results:
brighrnPss: 13.5 residual: 0.5% as 100%
gain: 8.0 points over no chelate e,~traction, with bl~rhing -E~Al~IPl.E 2 EDTANa, (2:1) mole ratio to total Fe. Mn. Cu E,l~ua~
pulp: 2nd stage (13.6 g as is) 5.0g OD
chelate: 5.30 mls of W~Jlhillg solution water: to 500 mls Ble~- hinu NaOH: 5.5 mls of worlcing solutio~
Silicate: 3.33 mls of working solution Peroxide: 1.62 mls of working solution ResuLts:
F ~ ~ . 73 . 0 r~sidual: 0.6% as 100%
gaiu: 7.6 points over no chelate ~ ;~n, with bl~rhing E~LE 3 DTPANas (1:1) mole ratio to total Fe. Ivtn. Cu 1 0 E.~lrac~on:
pulp: 2nd s~age (13.6 g as is) 5.0g OD
chelate: 3.2 mls of working solution water: to 500 mls Bl~rhing:
NaOH: 5.5 mls of working solution SiLicate: 3.33 mls of working soLution Peroxide: 1.62 mls of WUlk.i~lg solution Results:
bri~ f ,~: 74.4 residuaL: 0.6% as 100~o gain: 8.9 points over ~o chelate ~ oll, wi~h ble~rhinçr E~AMPLE 4 DTPANa, (2:1) mole ratio to total Fe. ~tn. Cu E.c~cuon:
pulp: 2nd stage (13.6 g as is) 5.0g OD
chelate: 6.4 mls of wor~ing solution water: to 500 mls Ble~hinv NaOH: 5.5 mis of wolkillg solution Silicate: 3.33 mls of wor~V solution Pero~ide: 1.62 n~s of wu~hi~g solution Results:
~,ol,",~cs 73.7 residual: 0. 670 as 100 %
gain: 8.3 pointC over no chelate e~lracuion, with bleaching ED,A (1:1) mole ra~io to tolal Fe. ~[n. Cu E~action:
pulp: ~nd s~age (13.6 g as is) 5.0g OD
chelate: 2.39 mls of wu,l~, s~ ti~-n water. to 500 mls Ble~hing NaOH: 5.5 m~s of w~ i~ solution S~icate: 3.33 n~s of W~ g sollltiQn Pero~ide: 1.62 mls of W~ lg solution Results:
.
brightnPss: 75.1 residual: 0.6~o as 100%
gain: 9.9 points over ~o chelate e~traction, with bleaching EgAMPl.E 6 ED;A (2:1) mole ratio to total Fe. ~ln. Cu Extraction:
pulp: 2nd s~age (13.6 g as is) 5.0g OD
chelate: 4.78 mls of wor~cing solutior water: to 500 mls 1 0 Bleaching:
NaOH: ~.5 mls of working solution Silicale: 3.33 mls of working solution Peroxide: 1.62 mls of wor.cing solution Results:
brighm~ss: 74.3 residual: 0.6% as 100%
gain: 8.9 points over uo chelate eYlT~rrir,n with blea~hino E~AMPI~: 7 Blank. no chelate E~traction:
pulp: 2nd stage (13.6 g as is) 5.0g OD
chelate: none water: to 500 mls 2 1 738~4 BIP~h;ng NaOH: 5.5 mls of working solution Silica~e: 3.33 mls of worlcing solution Pero~ide: 1.62 mls of wor~ing solution Results:
brightn~.c: 65.4 residual: 0.6% as 100a~o-gain: 0 The brighm~ readings are graphed on Figure 1. The use of 2:1 mole ratio of chelate to total me~al (Fe, lvLn, Cu) had no 5ignifi~nt ga ns in brightn~s.~, co~ cd to ~he use of a 1:1 mole ratio. ED;A l~ esa gain was 9.9 points over a no chelate treatment e~traction of pulp, and also showed an increase of l.9 points over EDTANal and 1.0 point increase in brighmpcc over DTPANa5.
The ne.~ se~ of c,~l~c~ lenL~ utilized a hi~her m~ng~nP~e pulp, aspen stone ground wood. The same con-liti-)n~ used in the ~lGviOua e~amples were used, e~ce?t that the %
NaOH was i~. leased to 2.6ra instead of 2.2%, in order to achie~e a higher irutiaL pH for ble~ h ing EDTA ~a (1:1) mole ~atio to total Fe. Mn. Cu E~raction:
pulp: Aspen SGW (137.4 g as is) 5.0g OD
chelate: 14.3 mls of w~"~g solution water: to 500 mis BIP~ hina 2 ~ 73824 ~aOH: 6.5 mls of working solution Silicate: 3.33 mls of working solution Peroxide: 1.62 mls of wor~ing solution Results:
brioh m~ss: 67.8 residual: 0.2 % as 100%
gain: i5 points over no chelate e~raction, without ble~ching - E~AMPLE 9 DTPA ~a (1 1) mole ratio to total Fe. hln. Cu 1 0 E~c~ac~ion:
pulp: Aspen SGW (137.4 g as is) 5.0g OD
chelate: 17.2 mls of working solution water- to 500 mls Ble~t~hina NaOH: 6.5 mls of working solution Silicate: 3.33 mls of wor~ing solution - Peroxide: 1.62 mls of wu~ lg solution Results:
brigh m~cc: 69.2 residual: 0.1% as 100%
gain: 16.8 poims over no chelate e,~ud~ , without ble~rhing E~ IPLE 10 ED,A (1:1) mole ratio to rDtal Fe. ~ln. Cu E,Ytrac~ion:
pulp: Aspen SGW (137.4 g as is) 5.0g OD
chelate: 12.9 mls of wor~ing solution water: to 500 mls BlP~rhina NaOH: 6.5 mls of wu.h~g solution Silicate: 3.33 mls of WO~ g solution Pero~ide: 1.62 mls of W013~illg solution Results:
brighmess: 68.9 residual: 0.1% as lOO~Yo gain: 16 points over no chela~e t:,~u~wn, withou~ blP~hina E~fPI.E 11 ED;A (1.25:1) mole raliO tO total Fe. Mn. Cu E,Y~action:
pulp: As;pen SGW (137.4 g as is) S.Og OD
chelate: 16.1 mls of WUlh~lg solution water: to Sû0 mls BlP~rhina NaOH: 6.5 mls of WUl~, solution Silica~e: 3.33 mls of wull~ g solution Pe,w~ide: 1.62 mLs of w~ g solution Results:
69.0 2~ 73824 -residual: O. l a~a as 100%
gain: 16.5 points over no chelate e~traction, without bleaching E~ E 12 Biank. no chelate e~ractian Exfraction:
pUlp: Aspen SGW (137.4 g as is) 5.0g OD
chelate: 0 water: to ~00 mls Bleaching:
NaOE~: 6.5 mls of worlcing solution Silicate: 3.33 mls of worl~ing solution Peroxide: 1.62 mls of worl~ing solution Results:
brighr~cc: 66.5 residu 1: 0.1% as lOOa~o gain: 13.4 points over no chelate e,~traction, without ble~hing -~ The brighmP~-~ gains are plotted in Figure 2, and the % iron and m~ng~nPse removal ~. .
- is plotted in Figure 3. ED,A u~sed at 1:1 mole ratio to me~als nad a greater briohfn~c~ gain than EDTANa~ (15 poin~s ve-sus 16), and when used at 25% excess, wa~s cu~ aLdble to DTPANa5. ~r;",~ f5e e~ctraction witn ED-,A was greater than 91%, which was fairly cu~ ble to EDTANa1 and DTPANa5 at 9~+ % .
Claims (8)
1. A method of inhibiting decomposition of hydrogen peroxide in aqueous solution containing transition metal ions, comprising contacting said solution with an effective amount of ethylenediaminetriacetic acid or a salt thereof for chelating said transition metal ions.
2. The method of claim 1, wherein said transition metal ions comprise iron, manganese and copper.
3. The method of claim 1, wherein said salt of ethylenediaminetriacetic acid is selected from the group consisting of alkali metal salts, alkaline earth metals salts, ammonium salt, and amine salts.
4. The method of claim 1, wherein said salt of ethylenediaminetriacetic acid is the sodium salt.
5. A method for pre-treating wood pulp prior to bleaching, comprising preparing an aqueous solution comprising said wood pulp and at least one transition metal ion, and adding to said aqueous solution an effective amount of ethylenediaminetriacetic acid or a salt thereof to chelate said at least one transition metal ion.
6. The method of claim 5, wherein said at least one transition metal ion is selected from the group consisting of iron, manganese, copper and a mixture thereof.
7. The method of claim 5, wherein said salt of ethylenediaminetriacetic acid is selected from the group consisting of alkali metal salts, alkaline earth metals salts, ammonium salt, and amine salts.
8. The method of claim 8, wherein said salt of ethylenediaminetriacetic acid is the sodium salt.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US43107895A | 1995-04-27 | 1995-04-27 | |
| US08/431,078 | 1995-04-27 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2173824A1 true CA2173824A1 (en) | 1996-10-28 |
Family
ID=23710353
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002173824A Abandoned CA2173824A1 (en) | 1995-04-27 | 1996-04-10 | Ethylenediaminetriacetic acid and salts thereof as chelating agents in pulp bleaching |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP0740015B1 (en) |
| AU (1) | AU693011B2 (en) |
| BR (1) | BR9602035A (en) |
| CA (1) | CA2173824A1 (en) |
| DE (1) | DE69606346T2 (en) |
| ES (1) | ES2144168T3 (en) |
| ZA (1) | ZA963060B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FI104572B (en) | 1996-05-30 | 2000-02-29 | Kemira Chemicals Oy | Chemical pulp bleaching process |
| FI105932B (en) * | 1996-05-30 | 2000-10-31 | Kemira Chemicals Oy | A process for bleaching high yield or recycled pulp |
| FI105214B (en) * | 1997-11-13 | 2000-06-30 | Kemira Chemicals Oy | Enhanced chemical pulp bleaching process |
| CA2728278C (en) | 2008-06-20 | 2016-06-28 | Zheng Tan | Composition and recording sheet with improved optical properties |
| US8258334B2 (en) | 2008-11-12 | 2012-09-04 | Irix Pharmaceuticals, Inc. | N-alkanoyl-N,N′,N′-alkylenediamine trialkanoic acid esters |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB8620222D0 (en) * | 1986-08-20 | 1986-10-01 | Abitibi Price Inc | Peroxide bleaching |
| US4732650A (en) * | 1986-09-15 | 1988-03-22 | The Dow Chemical Company | Bleaching of cellulosic pulps using hydrogen peroxide |
| US5250728A (en) * | 1991-12-12 | 1993-10-05 | Hampshire Chemical Corp. | Preparation of ethylenediaminetriacetic acid |
-
1996
- 1996-04-10 CA CA002173824A patent/CA2173824A1/en not_active Abandoned
- 1996-04-16 AU AU50668/96A patent/AU693011B2/en not_active Ceased
- 1996-04-17 ZA ZA963060A patent/ZA963060B/en unknown
- 1996-04-23 DE DE69606346T patent/DE69606346T2/en not_active Expired - Fee Related
- 1996-04-23 ES ES96106367T patent/ES2144168T3/en not_active Expired - Lifetime
- 1996-04-23 EP EP96106367A patent/EP0740015B1/en not_active Expired - Lifetime
- 1996-04-24 BR BR9602035A patent/BR9602035A/en active Search and Examination
Also Published As
| Publication number | Publication date |
|---|---|
| ZA963060B (en) | 1996-07-30 |
| EP0740015A1 (en) | 1996-10-30 |
| AU5066896A (en) | 1996-11-07 |
| EP0740015B1 (en) | 2000-01-26 |
| DE69606346D1 (en) | 2000-03-02 |
| ES2144168T3 (en) | 2000-06-01 |
| DE69606346T2 (en) | 2000-10-19 |
| AU693011B2 (en) | 1998-06-18 |
| BR9602035A (en) | 1998-10-06 |
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