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
• • 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
• • 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

Definitions

• This invention relates to transition metal complexes with polydentate ligands to enhance bleaching and Delignification effect of peroxygen compounds, their application and a method for delignifying Fibers.
• the fibers can also be several go through chemical and / or mechanical process stages have, for example, pulp and a first delignifying treatment after digestion.
• Lignin fibers from wood or annual plants for most uses should be from Lignin to be exempt.
• the fibers should also be high Have whiteness levels, preferably 90% ISO. These high Whiteness levels are only achieved when lignin is largely is removed from the fiber or from the fiber surface. With elemental chlorine and other chlorine-containing Bleaching chemicals could contain lignin fibers in the Past delignified efficiently and highly selectively become.
• the chlorine - free bleaching agents used for this purpose in the pulp industry should also be used Hydrogen peroxide.
• Hydrogen peroxide is mostly made up of Environmental reasons used. It is more expensive than bleach containing chlorine and significantly less selective. For these reasons, hydrogen peroxide is as low as possible mild conditions have so far been used where fibrous materials lightened but not delignified. at tightened reaction conditions, e.g. increased Temperature, increased use of chemicals and / or prolonged reaction time there is a certain amount Removal of remaining lignins, but this is accompanied from increased damage to the fiber and Yield losses. It is particularly undesirable that the unselective reaction of hydrogen peroxide to cellulose attacks so that the strength of the fiber becomes clear is reduced.
• the object of the invention based on a process for improved and selective Delignification and / or bleaching of lignin-containing Fibers using peroxygen and thereby developing environmentally friendly chemicals.
• Transition metal complex compounds of polydentate ligands with improved delignification and bleaching performance described.
• These polydentate ligands are organic Ligands which are in aqueous solution and in the presence of Atmospheric oxygen and / or hydrogen peroxide a complex form with a transition metal, especially cobalt, characterized in that the complexes one or are multinuclear and using these Peroxygen compounds better delignification and Have bleaching performance than conventional ones Transition metal complex compounds.
• transition metal complex compounds described here with polydentate ligands are also known as Bleaching catalysts called.
• polydentate ligands what is meant here are ligands which have at least 4 or more Heteroatoms (so-called donor atoms), preferably nitrogen, have, which coordinate to the transition metal ion can.
• Pentadentate ligands are preferred. Especially pentadentates are preferred in the present invention N-donor ligands used.
• a delignification and Bleaching process described in this Transition metal complex compounds with polydentates Ligands with improved delignification and Bleaching performance can be used as catalysts. It has been shown to be mononuclear Transition metal complex compounds of the general formula (1), especially those for low temperature bleaching of Textile fabrics in EP 0 909 809 and WO 00/12667 described mononuclear complexes of the formula (1a) with the pentadentate ligands N4Py and derivatives thereof, as Bleaching catalyst in which pulp bleaching is useful and can be applied there.
• solvents such as methanol, Water or mixtures thereof
• the use according to the invention of the transition metal complex compounds essentially consists of conditions create, among which the peroxygen compound and the Bleaching catalyst can react with each other
• the goal is to produce more oxidizing secondary products receive.
• Such conditions exist in particular if both reactants in aqueous solution meet.
• the aqueous fiber mass already contains the bleaching catalyst according to the invention.
• the Peroxygen compound can preferably be separately, as well as in Substance or as a preferably aqueous solution to the aqueous Fiber mass can be added.
• the Bleach catalyst if necessary, with others Bleaching additives, e.g. Sodium hydroxide solution in the aqueous Fiber mass can be kneaded.
• the bleaching catalyst can also be used "in situ" be prepared by adding the metal salt separately and the ligand or its salt to the aqueous solution of the Bleach additives, which are then added to the fiber mass is mixed in. In such an "in-situ” procedure the bleach catalyst cannot be isolated.
• the well-known, only lightening peroxide level clearly be increased, the cellulose only slightly is broken down. It is particularly surprising that this Rates of increase with rather low residual lignin contents can be achieved where experience has shown that it is particularly difficult degradable, highly condensed and therefore less reactive Lignin structures are present.
• the method according to the invention is very different Applicable fiber types, such as mechanical and / or chemical pretreated fibers including waste paper fibers, however also on untreated natural fibers.
• Hydrogen peroxide or Hydrogen peroxide-releasing compounds however, too organic or inorganic peracids or their salts, for example peracetic acid, peroxymonosulfuric acid or Percarboxylic acid and its salts are used.
• organic or inorganic peracids or their salts for example peracetic acid, peroxymonosulfuric acid or Percarboxylic acid and its salts are used.
• a delignification level can be mixed various peroxygen compounds are used. This is a vote on special Process requirements possible.
• the process according to the invention is broad Fabric density range applicable (fabric density is equal to proportion absolutely dry (atro) fiber mass on total weight).
• the consistency can be between 3% and 40%, but it is preferably between 10% and 15% consistency.
• the method according to the invention shows excellent Delignification or bleaching results if between 10 ppm to 5000 ppm, preferably 50 ppm to 3000 ppm, preferably 200 ppm to 2000 ppm, and particularly preferably between 200 ppm and 1500 ppm of the transition metal complex according to the invention, based on absolutely dry (atro) fiber mass can be used.
• the Degradation of the residual lignin occurs very efficiently when the pH at the beginning of the reaction above 10, preferably above 11 lies.
• the reaction temperature may vary depending on the selected fiber raw material in a wide range become. Between 20 ° C and 130 ° C, but preferably Most fibers can be between 40 ° C and 110 ° C delignify. The is particularly preferred Temperature range between 50 ° C and 98 ° C, because here under mild conditions is delignified very selectively, and this with relatively short reaction times.
• the reaction time can, in coordination with the Reaction temperature also in a wide range, between 5 and 240 minutes (min). Prefers however, a reaction time of 30 to 150 min. Delignification is particularly extensive if that Process applied over a period of 45 to 120 min becomes. These response times are shorter than with conventional ones Peroxide levels.
• the invention for delignification and / or bleaching transition metal complexes not only improve the effect of a simple peroxide stage, they increase also the delignification or bleaching of one Oxygen level carried out with the addition of peroxide becomes. Is bleached with the addition of oxygen achieved particularly good results when overpressure between 0.15 MPa and 1.5 MPa is used. Especially a reaction pressure of 0.2 MPa to 0.9 MPa is preferred applied.
• transition metal ions has an effect advantageous.
• DTPA Diethylenetriaminepentaacetic acid
• DTPMPA Diethylenetriaminepentamethylenephosphonic acid
• Poly- ⁇ -hydroxyacrylic acid even at higher pH values are stable.
• the Kappa number was based on the Zellcheming specification leaflet IV / 37/80 determined.
• the viscosity of the pulps was reduced determined according to TAPPI regulation T230 om-82.
• the whiteness was measured with an Elrepho 2000 (from Datacolor).
• Table 1 clearly shows that by using the catalysts (Co-N4Py) 2 ( ⁇ -O 2 ) and (Co-MeN4Py) 2 ( ⁇ -O 2 ), rates of increase in the delignification of up to 65% can be achieved, which clearly exceeds the delignification and bleaching performance of the comparison catalyst Mn-TMTACN ( ⁇ -O) 3 (VK 2).
• the ligand or its salt and the corresponding transition metal salt were dissolved in water and added to an aqueous solution of MgSO 4 , DTPA and NaOH. This solution was kneaded into 30 g of dry cellulose. The appropriate amount of hydrogen peroxide was then mixed in and the pH was measured. The cellulose thus prepared was then tempered in a PE bag in a water bath. The results without addition of ligand (Comparative Example A) and with the ligand N4Py or its salt are shown in Table 2.

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

Applications Claiming Priority (2)

Publications (1)

Family

ID=7660017

Family Applications (1)

Country Status (8)

Cited By (1)

Families Citing this family (22)

• 2000
  • 2000-10-17 DE DE10051317A patent/DE10051317A1/de not_active Withdrawn
• 2001
  • 2001-08-28 EP EP01120456A patent/EP1199402A2/fr not_active Withdrawn
  • 2001-10-16 NO NO20015027A patent/NO20015027L/no not_active Application Discontinuation
  • 2001-10-16 CA CA002359162A patent/CA2359162A1/fr not_active Abandoned
  • 2001-10-16 ZA ZA200108492A patent/ZA200108492B/xx unknown
  • 2001-10-17 KR KR1020010064056A patent/KR20020030731A/ko not_active Application Discontinuation
  • 2001-10-17 BR BR0104611-0A patent/BR0104611A/pt not_active Application Discontinuation
  • 2001-10-17 US US09/978,101 patent/US20020066542A1/en not_active Abandoned

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