WO2001007485A1 - Procede de depolymerisation selective de polysaccharides - Google Patents

Procede de depolymerisation selective de polysaccharides Download PDF

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Publication number
WO2001007485A1
WO2001007485A1 PCT/EP2000/007240 EP0007240W WO0107485A1 WO 2001007485 A1 WO2001007485 A1 WO 2001007485A1 EP 0007240 W EP0007240 W EP 0007240W WO 0107485 A1 WO0107485 A1 WO 0107485A1
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Prior art keywords
polysaccharide
cellulose
degree
urea
mixture
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PCT/EP2000/007240
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German (de)
English (en)
Inventor
Ties Karstens
Gerhard Kettenbach
Taina Seger
Armin Stein
Hans Steinmeier
Günter Mauer
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Rhodia Acetow Gmbh
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Priority to AU68304/00A priority Critical patent/AU6830400A/en
Publication of WO2001007485A1 publication Critical patent/WO2001007485A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08B—POLYSACCHARIDES; DERIVATIVES THEREOF
    • C08B31/00—Preparation of derivatives of starch
    • C08B31/18—Oxidised starch
    • C08B31/185—Derivatives of oxidised starch, e.g. crosslinked oxidised starch
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08B—POLYSACCHARIDES; DERIVATIVES THEREOF
    • C08B1/00—Preparatory treatment of cellulose for making derivatives thereof, e.g. pre-treatment, pre-soaking, activation
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08B—POLYSACCHARIDES; DERIVATIVES THEREOF
    • C08B15/00—Preparation of other cellulose derivatives or modified cellulose, e.g. complexes
    • C08B15/02—Oxycellulose; Hydrocellulose; Cellulosehydrate, e.g. microcrystalline cellulose
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08B—POLYSACCHARIDES; DERIVATIVES THEREOF
    • C08B15/00—Preparation of other cellulose derivatives or modified cellulose, e.g. complexes
    • C08B15/05—Derivatives containing elements other than carbon, hydrogen, oxygen, halogens or sulfur
    • C08B15/06—Derivatives containing elements other than carbon, hydrogen, oxygen, halogens or sulfur containing nitrogen, e.g. carbamates
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/04—Oxygen-containing compounds
    • C08K5/14—Peroxides

Definitions

  • the invention relates to a method for the targeted depolymerization of polysaccharides. It also relates to a mixture of at least one polysaccharide, at least one peroxo compound and optionally a derivatization reagent.
  • Polysaccharides are macromolecular carbohydrates, the molecules of which consist of monosaccharide molecules linked to one another by glycosides, with a degree of polymerization DP (average number of monomer units bound in the macromolecule), for example from about 500 to 10,000.
  • DP average number of monomer units bound in the macromolecule
  • cellulose is a linear polysaccharide composed of glucose monomer units, the smallest macroscopic structural elements being native cellulose elementary crystallites, which consist of cellulose molecules that are assembled in parallel. Disordered molecular segments link them into long strands, the so-called elementary fibrils. These elementary fibrils can meet along a variable length to form secondary aggregates, the length and degree of aggregation of which form characteristic structural features.
  • Chemical pulps typically have polymerization values DP> 700.
  • the DP degradation inevitably preceding the production of conventional cellulose derivatives serves on the one hand to achieve the degree of polymerization DP that is to be achieved for the cellulose derivative, but on the other hand also to increase accessibility and reactivity (activation).
  • the DP is adjusted by acid-catalyzed DP degradation.
  • the acid used often also serves as a catalyst for the esterification reaction.
  • the competition between chain dismantling and esterification is not always easy to manage.
  • the degree of polymerization DP is reduced during the alkali treatment. This takes place in the so-called ripening process, a process step in which the alkalized cellulose fibers are oxidatively exposed to air be dismantled. As a result of the heterogeneous conditions, superficial drying and thus an inhomogeneous DP reduction is practically unavoidable.
  • WO 83/02278 describes a process for the production of cellulose carbamate, the cellulose in web form first being irradiated with an irradiation dose of 0.5 to 10 Mrad, and this is then reacted with urea at an elevated temperature.
  • a widely known derivatization of cellulose is, for example, the production of cellulose carbamate, which is prepared from cellulose and urea with the following reaction:
  • the cellulose is mixed with excess urea in aqueous solution, the water content of the mixture is exchanged for the organic reaction carrier and in an inert liquid organic reaction carrier at a temperature of 130 to 160 ° C. to cellulose secarbamat implemented.
  • the cellulose used preferably has a degree of polymerization DP of 200 to 500, preferably 300 to 400.
  • EP 0 057 105 cellulose is treated with a liquid ammonia solution below the reaction temperature and the ammonia is then removed. Thereupon the cellulose with the urea dispersed therein is converted into an alkali-soluble cellulose carbamate product.
  • the focus is on the homogeneous activation of the cellulose by widening the crystal structure, as a result of which the properties and thus the quality of the derivatization product to be produced are influenced.
  • the degree of polymerization DP of the polysaccharide in a targeted manner.
  • the DP setting is a major disadvantage in the production of cellulose carbamate, since the chemical reaction of the cellulosic OH groups with HNCO (isocyanic acid) takes place without any significant DP degradation of the cellulose. Isocyanic acid arises from the thermal decomposition of urea.
  • NaOH activation is also extremely disadvantageous, because the urea must be neutralized before addition and thermal decomposition, which leads to the formation of salts.
  • the use of this mining method therefore requires a great deal of energy and chemicals.
  • DE 691 29 608 T2 describes a process which is used to produce an aqueous polysaccharide product with a high solids content and low viscosity, a depolymerizing peroxide being added to water and then the polysaccharide (s) having a solids content of 5 to 50 wt .-% are added, whereupon the reaction is carried out with the addition of further polysaccharide and oxidizing agent.
  • the exact order of addition must be observed here, since otherwise a gel layer is formed on the polymer aggregates formed (so-called “gel blocking”), which prevents further implementation.
  • the invention is therefore based on the object of developing the known methods in such a way that the disadvantages of the prior art are largely eliminated.
  • the aim is to provide a process for the gentle and targeted lowering of the degree of polymerization (depolymerization) of polysaccharides, as is customary for polysaccharide derivatives. It should be possible to do without complex recovery steps or intermediate stages. In particular, it should be possible, starting from commercially available polysaccharides, to prepare derivatives in one step and bring them to the desired DP.
  • this object is achieved by a process for the targeted depolymerization of polysaccharides or derivatives at elevated temperature, with the steps:
  • step (i) mixing at least one polysaccharide with a predetermined amount of at least one peroxo compound, (ii) optionally reacting the polysaccharide of the mixture with a derivatizing reagent to form a polysaccharide derivative, depending on the elevated temperature specifically set in step (i) and / or step (ii), a predetermined lowering of the degree of polymerization DP takes place and in the case of the production of polyethers those with more than 0.01 2-propenyl groups are excluded are substituted per anhydroglucose unit. It is also preferable to fall below the above range, so that about 0.005 2-propenyl groups per anhydroglycose unit or less are present in the polyether and in particular can also be completely excluded.
  • the invention also relates to a mixture comprising at least one polysaccharide and at least one peroxo compound, obtainable by mixing the polysaccharide with a predetermined amount of a peroxo compound.
  • This mixture can optionally additionally contain a derivatization reagent.
  • a method for targeted DP adjustment in the synthesis of polysaccharide derivatives using an oxidizing agent in the form of a peroxo compound is described.
  • the impregnation of polysaccharides with peroxo compounds allows a controlled breakdown of polysaccharides into a DP range, as is desired for the production of specific polysaccharide derivatives.
  • step (i) By mixing the polysaccharide in step (i) with a predetermined amount of a peroxo compound, a correspondingly stable mixture is already obtained, which, if necessary, is isolated in the form of a premix after gentle drying at a temperature in the range from about 20 ° C. to about 80 ° C. can be stored and transported.
  • This premix which does not yet contain a depolymerized polysaccharide, can also be processed immediately.
  • the mixing in step (i) can be carried out, for example, by grinding with thorough mixing. It goes without saying that no percarbamide or a corresponding compound may be present when mixing or grinding, since there is a risk of extrusion due to their unstable character.
  • the peroxo compound causes the polysaccharide to degrade rapidly, ie a Targeted lowering of the degree of polymerization DP achieved.
  • the degree of polymerization can also be controlled, for example, by the amount of peroxo compound used.
  • the polysaccharide can also be comminuted before step (i). This can be done with any size reduction or grinding device.
  • step (ii) the polysaccharide of the mixture, which depending on the temperature selected in step (i) is either already depolymerized or is present in the form of the premix described above, can be reacted with a derivatization reagent to give a polysaccharide derivative.
  • Appropriate temperature control also makes it possible in this step to lower the degree of polymerization DP to the desired extent. Accordingly, in step (i) and / or step (ii), depending on the set temperature, the degree of polymerization can be influenced in a targeted manner.
  • the process according to the invention thus allows the macromolecule to be degraded in a controllable manner before and / or during a desired derivatization reaction by the action of a peroxo compound on a polysaccharide.
  • the special feature of the process according to the invention is that the process can be interrupted in step (i) and a stable premix of polysaccharide (s) and peroxide (s) is obtained.
  • This premix can also be further processed immediately without interrupting the process and without isolating the premix, whereby a depolymerized polysaccharide or derivative is obtained when the temperature is set appropriately, for example while the premix is drying.
  • polysaccharides can be used in the process according to the invention.
  • they are polysaccharides that have a polyhexose backbone, i.e. a scaffold whose monomers are C ⁇ saccharides.
  • These include the biopolymers starch, cellulose, inulin, chitin and alginic acid, of which cellulose and starch are preferred.
  • the polysaccharides mentioned each contain only one type of building block - albeit possibly in alternating glycosidic linkages - and are therefore attributable to the homoglycans.
  • Polysaccharides which can likewise be used according to the invention are, in addition, heteroglycans composed of various monomer units.
  • the preferred heteroglycans include the galactomannans, of which guar gum is particularly preferred.
  • the polysaccharides used according to the invention should preferably be protein-free, so that no undesirable side reactions occur during the derivatization. Because most polysaccharides are hygroscopic and during storage Ambient conditions absorb water, appropriate drying steps before further processing are recommended depending on the further implementation.
  • the derivatization reagent can be obtained, for example, from urea, methyl chloride, ethyl chloride, chloroacetic acid, ethylene oxide, propylene oxide, 1,2-butylene oxide, acrylonitrile (cyanoethylation), acetic anhydride, propanoic anhydride, butanoic anhydride, isobutanoic anhydride, acetyl chlorides as higher fatty acids, ph Lactones such as caprolactone, N, N-bis (trimethylsilyl) acetamide, hexamethyldisilazane, N, N-bis (trimethylsilyl) carbamate, N, N-bis (trimethylsilyl) urea, carbon disulfide and mixtures thereof are selected from the group become.
  • the derivatization reagent is not limited to the aforementioned ones, to the exclusion of etherification of cellulose. Rather, the person skilled in the art is familiar with further
  • Peroxo components for the process according to the invention are percarbamide, which exhibits optimum solubility in ammonia and water, hydrogen peroxide, which forms percarbamide with urea, inorganic hydrogen peroxide adducts, such as percarbonates and / or perborates, or mixtures thereof.
  • 1 part by mass of polysaccharide preferably accounts for about 0.005 to 0.05 part by mass, in particular approximately 0.01 to 0.03 part by mass of peroxo compound.
  • the polysaccharide is pretreated with an aqueous or ammoniacal aqueous solution of the derivatizing reagent and / or the peroxo compound with swelling.
  • an aqueous or ammoniacal aqueous solution of the derivatizing reagent and / or the peroxo compound with swelling for example so-called never-dried pulp (which as such has never been dry), ie freshly disintegrated pulp before pressing and / or before drying, with (a) peroxo compound (s) and / or (a) Derivatization reagent (ien) are pretreated.
  • the pretreated polysaccharide obtained is then either gently dried and the water removed presses or removed by distillation or the polysaccharide obtained is immediately processed in step (i) without further workup.
  • the derivatization reagent can already be added in step (i), which can be advantageous depending on the desired procedure and the desired derivatization product.
  • the derivatization reagent and / or the peroxo compound can be used as solids.
  • the polysaccharide is then dry mixed with a predetermined amount of the peroxo compound and optionally the desired derivatizing reagent.
  • an intimate mixing of the composition can take place by any known mixing device, after which a corresponding derivatization reaction of the polysaccharide can immediately follow.
  • the mixing after step (i) can preferably be carried out in liquid ammonia.
  • the liquid ammonia can then be removed by introducing nitrogen gas or by a so-called ammonia explosion.
  • the liquid ammonia is preferably brought into contact in a pressure device, and the mixture is expanded by transferring it into an explosion space with a larger volume than the pressure device.
  • Derivatization reagent / liquid ammonia available volumes explosively increased by lowering the pressure by at least 5 bar.
  • the temperature is preferably set to about 25 to 85 ° C.
  • the contact time of the liquid ammonia with the other starting materials within the pressure vessel is usually about 20 minutes.
  • 1 part by mass of polysaccharide preferably accounts for at least about 0.5 part by mass, preferably at least about 1 part by mass, in particular approximately 2 to 10 parts by mass of liquid ammonia. The action of the ammonia causes the polysaccharide to swell at least partially.
  • a particularly preferred starting material for carrying out the process according to the invention are chemical pulps.
  • a cellulose starting material in the form of plates, rolls, bales or leaves has a density of about 0.6 to 0.8 g / cm 3 as a compact chemical cellulose.
  • the cellulose used according to the invention is preferably chemically pure. It preferably contains less than 18% by mass, in particular less than 9% by mass, of foreign substances.
  • the cellulose starting material preferably has a water content of less than about 12% by mass, in particular less than about 9% by mass. Since cellulose is to a certain extent hygroscopic and absorbs water during storage at ambient conditions, it may be necessary to subject the cellulose to suitable drying steps in order to maintain a low water or moisture content.
  • the derivatization reactions used in step (ii) in the context of the invention are in particular acylation, e.g. Acetylation, silylation, xanthation or production of carbamates and alkylation by etherification with alkyl halides, epoxy compounds, unsaturated organic compounds (Michael addition) and the like.
  • acylation e.g. Acetylation, silylation, xanthation or production of carbamates and alkylation by etherification with alkyl halides, epoxy compounds, unsaturated organic compounds (Michael addition) and the like.
  • This list of derivatization processes is not restrictive, but cellulose ethers are excluded from the teaching according to the invention.
  • the cellulose derivative produced preferably has a degree of substitution in the range from about 0.01 to 3.0.
  • cellulose carbamate is produced as the cellulose derivative. At least about 2 parts by weight of urea are preferably used per 10 parts by weight of cellulose. This is done at a reaction temperature heated between about 110 and 150 ° C, in particular a temperature greater than about 130 ° C. The necessary reaction time is usually one hour to several hours. The reaction is preferably carried out below atmospheric pressure. The heating can be done dry or alternatively in an inert liquid organic reaction carrier. Linear branched alkanes and / or alkyl aromatic hydrocarbons, each with a boiling point of 100 to 185 ° C.
  • cellulose carbamate is suspended in a water-miscible polar organic solvent with a boiling point of about 110 to 185 ° C., in particular more than about 130 ° C., and then reacted.
  • N-methylpyrrolidone and / or cellosolve are suitable as organic solvents.
  • the heating and the reaction between cellulose and urea are preferably carried out by boiling the inert organic reaction carrier or by passing an inert gaseous medium through, preferably at a pressure below atmospheric pressure, the NH3 formed, together with the NH3 remaining from the activation step, being rapidly removed is withdrawn from the reactor.
  • the derivatization reactions can be carried out by dry heating or in an inert liquid organic reaction carrier. After the reaction, the inert organic reaction carrier and any unreacted derivatization reagent removed from the polysaccharide derivative obtained.
  • the inert organic reaction carrier can initially be largely mechanically separated, the residue mixed with an aqueous medium and the remaining organic reaction carrier with a part of the aqueous medium removed by azeotropic distillation.
  • the inert organic reaction carrier can, if desired, be recovered according to known methods and recycled into the method. Unreacted derivatization reagent can also be removed, for example, by filtration.
  • the inert organic reaction carrier present and, if appropriate, unreacted urea are removed from the cellulose carbamate obtained.
  • the inert organic reaction carrier is preferably removed by first separating it largely mechanically, mixing the residue with an aqueous medium and removing the remaining organic reaction carrier with part of the aqueous medium by azeotropic distillation. The aqueous solution containing the unreacted urea is removed from the cellulose carbamate by filtering.
  • the inert organic reaction carrier is removed by first separating it largely mechanically and by washing the residue with a lower alcohol, for example a G-Gt alcohol.
  • the lower alcohol is preferably methanol, ethanol, n-propanol, isopropanol or a mixture thereof.
  • Both the inert organic reaction carrier and any unreacted urea dissolve very well in the lower alcohol.
  • the washing solution consisting of alcohol, inert organic reaction carrier and optionally urea is preferably worked up by distilling the lower alcohol from the inert organic reaction carrier out of the washing solution, condensing it and using it to remove the reaction carrier again and also returns the inert organic reaction carrier obtained.
  • the urea which may be present is insoluble in the inert organic reaction carrier and precipitates. It can be easily removed, for example by filtration. The filtered urea can also be returned to the process.
  • ammonia inert organic reaction carriers, lower alcohol and derivatizing reagent, such as urea, can advantageously be circulated.
  • the reaction product obtained can be suspended in an inert liquid, in particular xylene and / or toluene, in order to dissolve unreacted urea, and the suspension can then be filtered to remove the urea.
  • a sieve belt press is preferably used for the filtration, with part of the inert liquid preferably being removed by means of a dewatering drum before the filtration.
  • the inert liquid used is preferably removed hot and returned hot to the overall system.
  • the cellulose carbamate obtained can, for example, be dried and stored in a screw or rotary drum dryer or else be dissolved directly in alkali.
  • step (i) and step (ii) are shown here by means of a flow chart, the polysaccharide used being cellulose in this case.
  • the cellulose starting material is first crushed by grinding and then impregnated with a peroxo compound with mixing without using water as the solvent (step (i)).
  • the mixture obtained can be stored after careful drying and can be used at a later time. are processed.
  • the subsequent reaction with any derivatization reagent to a cellulose derivative is carried out while lowering the degree of polymerization at a correspondingly elevated temperature.
  • the premix obtained from cellulose and peroxo compound can be dried under a correspondingly elevated temperature in order to achieve a reduction in the degree of polymerization to the desired extent.
  • the mixture is then reacted with a derivatizing reagent either immediately afterwards or at a later point in time in order to obtain the cellulose derivative with the desired degree of polymerization depending on the temperature used (step (ii)).
  • the invention is distinguished by a number of advantages:
  • the targeted setting of the DP in the case of commercially available polysaccharides in the DP range sought for the respective polysaccharide derivative using a few% by mass of a peroxo compound is one of the methods introduced on an industrial scale considerable advantage since the polysaccharide derivative is obtained directly without special pretreatment.
  • the premix can generally be prepared without the use of solvents, in particular without water, it also being possible, if appropriate, to use the derivatizing reagent or the peroxo compound as solids.
  • the conversion of the solids is not limited, but can also use appropriate solvents.
  • the simple procedure of the invention means that complicated upstream activation steps or treatment processes are not necessary.
  • the depolymerization reaction proceeds quickly and selectively, so that the mixing (impregnation) and the conversion to the polysaccharide derivative can be carried out in parallel.
  • the polysaccharide impregnated with the peroxo compound can be gently dried. This allows the impregnated and dried polysaccharide to be stored and transported in the form of a reactive premix.
  • the process according to the invention also enables a wide range of variants, so that the polysaccharide of the impregnated mixture of polysaccharide and peroxo compound can be reacted with any derivatization reagent and a targeted adjustment of the degree of polymerization can be carried out either before and / or during the reaction, but cellulose ethers are excluded ,
  • polysaccharide derivatives are thus made available in a simple, very economical process in a quality which has hitherto been possible only by separate pretreatments of the starting materials, i.e. previous lowering of the degree of polymerization, or using certain solvents with a given order of addition of the reagents, could be achieved.
  • Embodiment 1 The invention will be explained in more detail below with the aid of various examples: Embodiment 1;
  • a solution of 120 g urea in 11 water is heated to 60 ° C.
  • the pulp is squeezed to a weight of 280 g in a porcelain suction filter, roughly crushed and then dried in a drying cabinet at 40 ° C. for about 48 hours. This gave 103 g of the impregnated pulp.
  • the mixture is reacted as described in Example 1.
  • the pulp suspension is heated under reflux at 136 ° C. for 3 hours.
  • the filter value (clogging number) is defined in: H. Sithola, Paperi ja Puu 44 (1962), No.5, p. 295-300.
  • the filter values were determined using a temperature-controlled filter device (according to ZELLCHEMING data sheet III / 4/66) with a reduced filter area (4 cm 2 ).
  • the filter fabric was Polynova (quality 2843 PP, VERSEID AG-TECHFAB GmbH).
  • the filter value was corrected for viscosity according to the following relationship:
  • FWcorr FW measured XA [Cm 2 ] / (KF [s] ° 4 ) where A is the filter area and KF is the falling ball viscosity.
  • the filter value is used to assess the quality of the sodium alkaline cellulose carbamate solution. The smaller the filter value, the better the filterability of the solution.
  • a solution of 120 g urea in 11 water is heated to 60 ° C.
  • DP 1050, moisture ⁇ 5%
  • the mixture is cooled below 40 ° C, is added a solution of 10 g percarbamide in 50 ml of water and stirred again x hour.
  • the pulp is pressed to a weight of 350 g in a porcelain suction filter, roughly crushed and then dried in a drying cabinet at 40 ° C. for about 48 hours. This gave 135 g of the impregnated pulp.
  • the impregnated pulp is converted as described in Example 1.
  • the impregnated pulp is converted as described in Example 1.
  • a prefabricated mixture of 1000 g (5.8 mol) of ground cellulose (Weyerney, DP 1050, moisture 6%, powder ⁇ 0.4 mm) and 349 g (5.8 mol) of pulverized urea is suspended in a 25 liter reactor with 201 xylene with stirring , 35 g (0.37 mol) of powdered percarbamide are added to this suspension with intensive stirring and stirring is continued for 1 hour at room temperature.
  • the reaction mixture is then heated to boiling temperature within 1 h. Approx. 60 ml of water are distilled off as an azeotrope and collected in a water separator.
  • the reaction mixture is then stirred for 4 h x hours at boiling temperature, being set in R forcinggemisch a temperature of about 139 ° C.
  • the resulting ammonia gas is transferred to an exhaust gas scrubber with a weak stream of nitrogen and absorbed in water.
  • the reaction product is filtered off with 6 l of methanol, then washed with 301 hot (60 ° C.) water and a further 301 cold water.
  • the filter cake is pressed to a weight of approx.2.5kg. After drying in a circulating air drying cabinet 24 hours at 80 ° C, 980 g of cellulose carbamate (residual moisture 3.5%) are obtained.
  • the cellulose carbamate thus produced is dissolved at -7 ° C. in aqueous sodium hydroxide solution (composition of the solution: 6% by mass of cellulose carbamate, 8% by mass of NaOH, 1.7% by mass of urea and 84.3% by mass of water).
  • aqueous sodium hydroxide solution composition of the solution: 6% by mass of cellulose carbamate, 8% by mass of NaOH, 1.7% by mass of urea and 84.3% by mass of water.
  • the solution is filtered at 5 ° C.

Abstract

La présente invention concerne un procédé de dépolymérisation sélective de polysaccharides ou de leurs dérivés, à température élevée, ledit procédé comprenant les étapes suivantes: (i) mélange d'au moins un polysaccharide avec une quantité prédéterminée d'au moins un composé peroxo; (ii) éventuellement transformation du polysaccharide du mélange avec un réactif de désactivation pour donner un dérivé de polysaccharide, ce qui permet une diminution prédéterminée du degré de polymérisation (DP) en fonction de la température élevée réglée de manière sélective durant les étapes (i) et/ou (ii), et, dans le cas de la préparation de polyéthers, l'exclusion de ceux qui sont substitués avec plus de 0,01 groupes 2-propényle par unité d'anhydroglucose. Cette invention concerne également un mélange comprenant au moins un polysaccharide et au moins un composé peroxo, obtenu par mélange du/des polysaccharide(s) avec une quantité prédéterminée du/des composé(s) peroxo. Le procédé de l'invention permet une dépolymérisation en une seule étape de polysaccharides courants dans le commerce, et la préparation simultanée ou ultérieure de dérivés ayant un degré de polymérisation (DP) souhaité.
PCT/EP2000/007240 1999-07-28 2000-07-27 Procede de depolymerisation selective de polysaccharides WO2001007485A1 (fr)

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AU68304/00A AU6830400A (en) 1999-07-28 2000-07-27 Method for carrying out the targeted depolymerization of polysaccharides

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Cited By (7)

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WO2004007559A1 (fr) * 2002-07-10 2004-01-22 Akzo Nobel N.V. Depolymerisation de polysaccharides solubles dans l'eau
US6866860B2 (en) 2002-12-19 2005-03-15 Ethicon, Inc. Cationic alkyd polyesters for medical applications
US6884884B2 (en) 2001-06-11 2005-04-26 Rhodia, Inc. Galactomannan compositions and methods for making and using same
DE102010052602A1 (de) * 2010-11-25 2012-05-31 Studiengesellschaft Kohle Mbh Verfahren zur säurekatalysierten Depolymerisation von Cellulose
WO2013050300A2 (fr) 2011-10-03 2013-04-11 Lamberti Spa Dépolymérisation de polysaccharides et de produits apparentés
WO2015198218A1 (fr) * 2014-06-27 2015-12-30 Stora Enso Oyj Procédé permettant la fabrication de carbamate de cellulose
EP3231899A1 (fr) 2016-04-14 2017-10-18 TreeToTextile AB Procédé et système pour la production d'une composition de solution à filer

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WO2015198218A1 (fr) * 2014-06-27 2015-12-30 Stora Enso Oyj Procédé permettant la fabrication de carbamate de cellulose
CN106661131A (zh) * 2014-06-27 2017-05-10 斯道拉恩索公司 制造纤维素氨基甲酸酯的方法
US20170145119A1 (en) * 2014-06-27 2017-05-25 Stora Enso Oyj Method for making cellulose carbamate
CN106661131B (zh) * 2014-06-27 2020-03-03 斯道拉恩索公司 制造纤维素氨基甲酸酯的方法
EP3231899A1 (fr) 2016-04-14 2017-10-18 TreeToTextile AB Procédé et système pour la production d'une composition de solution à filer
US11299556B2 (en) 2016-04-14 2022-04-12 Treetotextile Ab Method for the production of a spinning dope composition
US11753482B2 (en) 2016-04-14 2023-09-12 Treetotextile Ab System for the production of a spinning dope composition

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