EP0740015B1 - L'acide éthylène diamine tri-acétique et les sels obtenus à partir de celui-ci comme agents de chélation dans le blanchiment de pâte - Google Patents

L'acide éthylène diamine tri-acétique et les sels obtenus à partir de celui-ci comme agents de chélation dans le blanchiment de pâte Download PDF

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Publication number
EP0740015B1
EP0740015B1 EP96106367A EP96106367A EP0740015B1 EP 0740015 B1 EP0740015 B1 EP 0740015B1 EP 96106367 A EP96106367 A EP 96106367A EP 96106367 A EP96106367 A EP 96106367A EP 0740015 B1 EP0740015 B1 EP 0740015B1
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Prior art keywords
mls
bleaching
salt
pulp
salts
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EP96106367A
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German (de)
English (en)
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EP0740015A1 (fr
Inventor
Brian A. Parker
Roland J. Lemery
David T. Johns
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Hampshire Chemical Corp
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Hampshire Chemical Corp
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    • 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

Definitions

  • the invention pertains to a method of inhibiting decomposition of hydrogen peroxide as well as to a method for pre-treating wood pulp prior to bleaching.
  • Hydrogen peroxide solutions are commonly used for bleaching cellulosic materials, including paper pulps, cotton, linen, jute, etc.
  • the peroxide should be stabilized to prevent premature depletion thereof, in view of the deleterious presence of metal ions such as iron, manganese and copper.
  • sodium silicate has been used as a peroxide bleach stabilizer, but tends to form insoluble silicates which can be deposited onto the fibers being bleached, as well as onto the apparatus.
  • a pretreatment with a chelating agent is a standard operation in order to control the metal profile of the pulp.
  • Chelant pre-treatment is a key factor in achieving feasible brightness levels and viscosities upon bleaching/delignification with peroxide.
  • Decomposition of peroxide under alkaline conditions is greatly influenced by the presence of certain inorganic compounds which behave as peroxide decomposition catalysts. Transition metal ions, such as manganese, iron and copper are examples of such catalysts, and thus should be removed prior to bleaching. Such deleterious transition metal ions can be sequestered by the chelating agent and are subsequently washed out of the system in a subsequent washing step.
  • the bleaching process with peroxide usually takes place between a pH of 10 and 11 and a temperature of 71-77°C. Under these alkaline conditions, the following reaction occurs: H 2 O 2 + OH - ⁇ OOH - + H 2 O
  • the perhydroxyl ion (OOH - ) created is what performs the bleaching. However, if transition metals are present, the following reaction takes place: M + H 2 O 2 ⁇ M + + HO - + HO .
  • the radicals created enhance the decomposition process. Manganese is the metal of most concern when peroxide is the bleaching agent used.
  • hydro-sulfite When hydro-sulfite is the preferred bleaching agent, the metal of most concern is iron. Hydro-sulfite bleaches pulp by a reduction reaction with the chromofors 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.
  • 4,732,650 discloses the silicate-free bleaching of wood pulp by the combination of a pretreatment of the pulp with a polyaminocarboxylic acid or salt such as ethylenediaminetetraacetic acid, followed by a bleaching with a peroxide solution together with stabilizing components.
  • a polyaminocarboxylic acid or salt such as ethylenediaminetetraacetic acid
  • Ethylenediaminetriacetic acid (ED3A) and its salts (such as ED3ANa 3 ) have applications in the field of chelating chemistry, and may be used as a starting material in the preparation of strong chelating polymers, oil soluble chelants, surfactants and others.
  • Conventional routes for the synthesis of ethylenediaminetriacetic acid were achieved via its N-benzyl derivative, which was subsequently hydrolyzed in alkaline solutions to ED3ANa 3 , thus avoiding cyclization to its 2-oxo-1,4-piperazinediacetic acid (3KP) derivative.
  • 3KP 2-oxo-1,4-piperazinediacetic acid
  • One example of the synthesis of ethylenediamine-N,N,N'-triacetic acid is disclosed in Chemical Abstracts 78, Vol.
  • US-A-5,250,728 discloses a simple process for the synthesis of ED3A or its salts in high yield. Specifically, a salt of N,N'-ethylenediaminediacetic acid (ED2AH 2 ) is condensed with stoichiometric amounts, preferably slight molar excesses of, formaldehyde, at temperature between 0° and 110°C, preferably 0° to 65°C and pH's greater than 7.0 to form a stable 5-membered ring intermediate.
  • ED2AH 2 N,N'-ethylenediaminediacetic acid
  • a cyanide source such as gaseous or liquid hydrogen cyanide, aqueous solutions of hydrogen cyanide or alkali metal cyanide, in stoichiometric amounts or in a slight molar excess, across this cyclic material at temperatures between 0° and 110°C, preferably between 0° and 65°C, forms ethylenediamine N,N'-diacetic acid-N'-cyanomethyl or salts thereof (mononitrile-diacid).
  • a cyanide source such as gaseous or liquid hydrogen cyanide, aqueous solutions of hydrogen cyanide or alkali metal cyanide
  • the nitrile in aqueous solutions may be spontaneously cyclized in the presence of less than 3.0 moles base: mole ED2AH 2 , the base including alkali metal or alkaline earth metal hydroxides, to form 2-oxo-1,4-piperazinediacetic acid (3KP) or salts thereof, which is the desired cyclic intermediate.
  • base including alkali metal or alkaline earth metal hydroxides
  • 3KP 2-oxo-1,4-piperazinediacetic acid
  • salts of ED3A are formed in excellent yield and purity.
  • This patent also discloses an alternative embodiment in which the starting material is ED2AH a X b , where X is a base cation, e.g., an alkali or alkaline earth metal, a is 1 to 2, and b is 0 to 1 in aqueous solutions.
  • the reaction mixture also can be acidified to ensure complete formation of carboxymethyl-2-oxopiperazine (the lactam) prior to the reaction.
  • Formaldehyde is added, essentially resulting in the hydroxymethyl derivative.
  • a cyanide source 1-cyanomethyl-4-carboxymethyl-3-ketopiperazine (mononitrile monoacid) or a salt thereof is formed.
  • HOCH 2 CN which is the reaction product of formaldehyde and cyanide, may also be employed in this method.
  • this material may be hydrolyzed to 3KP. The addition of a base will open this ring structure to form the salt of ED3A.
  • ethylenediaminetriacetic acid (ED3A) and its salts now can be readily produced in bulk and high yield.
  • Use of ED3A and ED3A salts as chelating agents in pulp bleaching would result in a cost-effective process.
  • the inventors of the present invention have found that ED3A and ED3A salts actually enhance brightness and equal or outperform EDTA in such applications, notwithstanding the presence of only three carboxylate groups in ED3A as compared to four in EDTA.
  • Suitable salts of ethylenediaminediacetic acid that are useful in the present invention include alkali metal and alkaline earth metals, preferably sodium and potassium, and ammonium and amine (such as triethanol amine and monoethanolamine) salts, which can easily be prepared from ED3A acid by conventional means.
  • alkali metal and alkaline earth metals preferably sodium and potassium
  • ammonium and amine (such as triethanol amine and monoethanolamine) salts which can easily be prepared from ED3A acid by conventional means.
  • the sodium salt will be used, although it should be understood that other salts may be employed.
  • Step 1 in the overall reaction scheme for producing ED3A is the alkaline condensation of formaldehyde with N,N'-ethylenediamine disodium acetate to form a 5-membered ring structure, 1,3-bis(carboxymethyl)imidazolidine, and is illustrated as follows:
  • the above reaction may be carried out in the presence of additional base.
  • Suitable bases include alkali and alkaline earth metal hydroxides, preferably sodium and potassium hydroxide.
  • Compound (1) is the bridged reaction product of EDDANa (1.0 ⁇ 2.0) and formaldehyde, which the is a stable intermediate in the ED3A synthesis.
  • Compound (I) is formed easily between 0° and 110°C.
  • the Step I reaction proceeds quickly and forms readily at pH's greater than about 7.0.
  • the temperature employed is about 0 to 65°C, most preferably 15 to 65°C, although temperatures higher than 65°C are operable.
  • Formaldehyde can be used in stoichiometric amounts, although it is preferred that a slight molar excess be used, preferably 0.5%-2.0%. Preferably the concentration of the formaldehyde is 55% or less in aqueous solution. Paraformaldehyde also can be used.
  • Compound (II) is readily formed at temperatures between 0° and 110°C.
  • the reaction should be conducted at temperatures at or below the boiling point of the solution. Preferably the reaction is carried out at temperatures from about 0° to about 65°C, most preferably about 15° to 65°C to enhance the reaction rate.
  • Suitable sources of cyanide include gaseous hydrogen cyanide, an aqueous solution of hydrogen cyanide, or alkali metal cyanide such as sodium cyanide or potassium cyanide, etc.
  • the cyanide may be used in stoichiometric amounts, although slight molar excesses may be used, preferably 0.5% - 2.0%.
  • Step III in the reaction sequence is the hydrolysis of compound (II) to the monoamide-diacid compound (III) (partially hydrolyzed mononitrile diacid) and its spontaneous cyclization to 3KP.
  • Compound (IV) forms readily in the presence of a base such as alkali metal or alkaline earth metal hydroxides.
  • a base such as alkali metal or alkaline earth metal hydroxides.
  • the base is NaOH.
  • Mole ratios of ⁇ 3.0M base : 1M ED2AH 2 but preferably ⁇ 2.0 M base : 1M ED2AH 2 are employed. Higher concentrations of base (i.e.
  • M base : M ED2AH 2 cause some disproportionation of the diacid mononitrile and some ED4A (ethylenediaminetetraacetic acid) is formed, especially at temperatures > 65°C.
  • concentration of ED4A is found to be in direct proportion to the amount of excess caustic employed, when high temperature reactions are conducted and high molar ratios of base are employed (> 2.0M base : 1M ED2AH 2 ), which may be attributed to the simultaneous hydrolysis of 3KP and disproportionation of the mononitrile-diacid.
  • the mole ratio of base to ED2A is ⁇ 2.0, higher temperatures may be used.
  • Step III ammonia is eliminated between an amide group and an imino group on the same molecule.
  • higher amounts of base may be employed (> 2.0M) and hydrolysis of compound (II) can proceed directly to ED3A without cyclization.
  • Step IV is the hydrolysis of 3KPNa 2 by at least the addition of 1 equivalent of caustic, preferably a 1 molar excess of caustic. This amounts to approximately 5% weight excess (free) caustic in solution on a 40% ED3ANa 3 solution.
  • the solution is boiled under atmospheric pressure to the desired concentration.
  • the reaction is carried out by raising the temperature from the temperature in Step III to the boil over a period from about 30 minutes to about 6 hours.
  • the resulting solutions typically give approximately 35-40% ED3ANa 3 , with approximately 2% 3KPNa 2 remaining as an unopened ringed structure. This corresponds to about a 94% conversion to ED3ANa 3 , with the remaining 6% of mass existing as 3KPNa 2 . Acidification of this mass to pH's ⁇ 6.0 to produce ED3AH 3 is not possible, as cyclization to 3KPH 2 will eventually occur.
  • ED3A can be prepared using ED2AH a X b as the starting material, where x is a base, e.g., an alkali or alkaline earth metal, a is 1 to 2, and b is 0 to 1 in aqueous solutions.
  • the reaction mixture also can be acidified with acids having pK a 's less than or equal to 3, prior to during or after the addition of a cyanide source, to ensure complete formation of carboxymethyl-2-oxopiperazine (the lactam).
  • Formaldehyde is added, essentially resulting in the hydroxymethyl derivative.
  • EDDA can also be allowed to form the lactam (carboxymethyl-2-oxo-piperazine) by acidification, and the lactam is reacted with chloro or bromo acetic acid to form ED3A or 3KP.
  • lactam carboxymethyl-2-oxo-piperazine
  • the chelate pretreatment extraction in accordance with the present invention can be carried out in a pH range of from about 4 to about 11, preferably 4.5-5. Operable temperatures are from about room temperature to no higher than 100°C at atmospheric pressure, preferably about 50°C to about 90°C. Temperatures as high as 90°C actually improve the complexation of metals with the chelating agent.
  • Levels of chelating agent from about 1 to 10 kg per tonne (2 to about 20 pounds per ton) of pulp are typical in the pulp and paper industry for enhancing peroxide bleaching systems.
  • the actual amount used will depend upon the level of metals present; the amount of chelating agent being that amount effective for chelating sufficient metals in order to achieve desired brightness and avoid undesirable peroxide decomposition.
  • the metal content of the pulp is typically determined by sampling the pulp and determining its metal content by atomic adsorption. Chelates complex metals on a one-to-one molar basis.
  • the pulp is pretreated with ED3A and then washed so that the complexed metals are washed out of the system.
  • a residence time of at least thirty minutes is needed at this stage to allow the chelates to complex the metals present and subsequently be washed.
  • the chelate can be added to the pulp prior to bleaching (generally at pH's of 7-9) but without subsequent washing, or can be added directly to the bleaching process (generally pH's of 10-11), although these methods are generally less effective.
  • the efficiency of ethylenediaminetriacetic acid was compared along with EDTANa 4 and DTPANa 5 and no chelate in extraction of metals from two types of pulp, namely, sulfite, magnesium base 2nd stage unbleached supplied by Wausau Paper, and a mechanical pulp, Aspen Stone Ground Wood (SGW).
  • SGW Aspen Stone Ground Wood
  • Distilled water is added to the 500 ml mark, (1% consistency pulp).
  • the pH of the extraction slurry was 4.5 to 5.0.
  • the sample was stirred for 1/2 hour at room temperature and then was filtered through a Buchner funnel lined with a #4 Whatman filter paper.
  • the wet weight of the pulp pad was recorded to be used later in reconstituting to 10% consistency. This procedure was repeated for all the chelates that where evaluated.
  • Bleaching was carried out in zip lock bags in a water bath set at 70° C. for two hours.
  • a bleach liquor 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 peroxide as 100% on 5 gm OD pulp, and water was added to make the pulp 10% consistency.
  • the pH before bleaching was 10.5.
  • the air was squeezed out of the bag and inserted in a water bath for 2 hours. After the two hours in the water bath, the bleached pulp was transferred to a 600 ml beaker and the pulp was diluted to 1% consistency, the sample was mixed and the pH was recorded.
  • the brightness readings are graphed on Figure 1.
  • the use of 2:1 mole ratio of chelate to total metal had no significant gains in brightness, compared to the use of a 1:1 mole ratio.
  • ED 3 A brightness gain was 9.9 points over a no chelate treatment extraction of pulp, and also showed an increase of 1.9 points over EDTANa 4 and 1.0 point increase in brightness over DTPANa 5 .
  • the next set of experiments utilized a higher manganese pulp, aspen stone ground wood.
  • the same conditions used in the previous examples were used, except that the % NaOH was increased to 2.6% instead of 2.2%, in order to achieve a higher initial pH for bleaching.
  • ED 3 A used at 1:1 mole ratio to metals had a greater brightness gain than EDTANa 4 (15 points versus 16), and when used at 25% excess, was comparable to DTPANa 5 .
  • Manganese extraction with ED 3 A was greater than 91%, which was fairly comparable to EDTANa 4 and DTPANa 5 at 97+%.

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  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Paper (AREA)
  • Detergent Compositions (AREA)

Claims (8)

  1. Méthode d'inhibition de la décomposition du peroxyde d'hydrogène dans une solution aqueuse contenant des ions de métaux de transition, comprenant la mise en contact de ladite solution avec une quantité efficace d'acide éthylènediaminetriacétique ou son sel pour chelater lesdits ions de métaux de transition.
  2. Méthode de la revendication 1, où lesdits ions de métaux de transition comprennent du fer, du manganèse et du cuivre.
  3. Méthode de la revendication 1, où ledit sel de l'acide éthylènediaminetriacétique est sélectionné dans le groupe consistant en sels de métaux alcalins, sels de métaux alcalinoterreux, sel d'ammonium et sels d'amine.
  4. Méthode de la revendication 1, où ledit sel de l'acide éthylènediaminetriacétique et le sel de sodium.
  5. Méthode pour le prétraitement de pâte de bois avant blanchiment avec un agent de blanchiment susceptible d'une décomposition par des ions de métaux de transition en solution aqueuse, consistant à préparer une solution aqueuse comprenant ladite pâte de bois qui est dispersée et au moins un ion d'un métal de transition est ajouté à ladite dispersion aqueuse, une quantité efficace d'acide éthylènediaminetriacétique ou son sel pour chélater ledit au moins un ion d'un métal de transition.
  6. Méthode de la revendication 5, où ledit au moins un ion d'un métal de transition est sélectionné dans le groupe consistant en fer, manganèse, cuivre et un mélange de ceux-ci.
  7. Méthode de la revendication 5, où ledit sel de l'acide éthylènediaminetriacétique est sélectionné dans le groupe consistant en sels de métaux alcalins, sels de métaux alcalinoterreux, sels d'ammonium et sels d'amine.
  8. Méthode de la revendication 8, où ledit sel de l'acide éthylènediaminetriacétique est le sel de sodium.
EP96106367A 1995-04-27 1996-04-23 L'acide éthylène diamine tri-acétique et les sels obtenus à partir de celui-ci comme agents de chélation dans le blanchiment de pâte Expired - Lifetime EP0740015B1 (fr)

Applications Claiming Priority (2)

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US43107895A 1995-04-27 1995-04-27
US431078 1995-04-27

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EP0740015B1 true EP0740015B1 (fr) 2000-01-26

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EP (1) EP0740015B1 (fr)
AU (1) AU693011B2 (fr)
BR (1) BR9602035A (fr)
CA (1) CA2173824A1 (fr)
DE (1) DE69606346T2 (fr)
ES (1) ES2144168T3 (fr)
ZA (1) ZA963060B (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8361571B2 (en) 2008-06-20 2013-01-29 International Paper Company Composition and recording sheet with improved optical properties

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FI105932B (fi) * 1996-05-30 2000-10-31 Kemira Chemicals Oy Menetelmä korkeasaanto- tai kierrätysmassan valkaisemiseksi
FI104572B (fi) 1996-05-30 2000-02-29 Kemira Chemicals Oy Menetelmä kemiallisen massan valkaisemiseksi
FI105214B (fi) * 1997-11-13 2000-06-30 Kemira Chemicals Oy Tehostettu kemiallisen massan valkaisumenetelmä
US8258334B2 (en) 2008-11-12 2012-09-04 Irix Pharmaceuticals, Inc. N-alkanoyl-N,N′,N′-alkylenediamine trialkanoic acid esters

Family Cites Families (3)

* Cited by examiner, † Cited by third party
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

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8361571B2 (en) 2008-06-20 2013-01-29 International Paper Company Composition and recording sheet with improved optical properties
US8906476B2 (en) 2008-06-20 2014-12-09 International Paper Company Composition and recording sheet with improved optical properties

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DE69606346D1 (de) 2000-03-02
ZA963060B (en) 1996-07-30
AU5066896A (en) 1996-11-07
ES2144168T3 (es) 2000-06-01
CA2173824A1 (fr) 1996-10-28
BR9602035A (pt) 1998-10-06
EP0740015A1 (fr) 1996-10-30
AU693011B2 (en) 1998-06-18
DE69606346T2 (de) 2000-10-19

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