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    • 专利摘要:
    methods for catalytic oxidation of cellulose and for producing a cellulose product, and, cellulose product. cellulose is catalytically oxidized using a heterocyclic nitroxyl radical as a catalyst, a main oxidant acting as an oxygen source, and a heterocyclic nitroxyl radical activator. the oxidation is carried out in a reaction medium which is of average consistency of cellulosic pulp, which is above 6%, more preferably equal to or greater than 8%, and most preferably in the range of 8 to 12%. the reaction medium is mixed in a reactor by circulating the feed medium back to the reactor.
    公开号:BR112015013465B1
    申请号:R112015013465-3
    申请日:2013-12-13
    公开日:2021-07-27
    发明作者:Markus Nuopponen；Taisto Tienvieri；Isko Kajanto；Tero Ojala；Sami SAARELA；Timo Pããkkõnen；Tapani Vuorinen
    申请人:Upm-Kymmene Corporation；
    IPC主号:
    专利说明:

    Field of Invention
    [0001] The invention relates to a method for catalytic oxidation of cellulose using a heterocyclic nitroxyl radical as catalyst. Fundamentals of the Invention
    [0002] Cellulose is a natural renewable polymer that can be converted into many chemical derivatives. Derivatization occurs mainly by chemical reactions of the hydroxyl groups on the β-D-glucopyranose units of the polymer. By chemical derivatization, the properties of cellulose can be changed compared to the original chemical form while retaining the polymeric structure. The selectivity of the reaction is important so that a desired chemical structure derivative can be obtained.
    [0003] Heterocyclic nitroxyl compounds are known as catalysts that participate in the selective oxidation of C-6 hydroxyl groups of cellulose molecules into aldehydes and carboxylic acids, the corresponding oxoammonium salt being known as the active direct oxidant in the series of reactions. One of these old well known chemical oxidation catalysts is "TEMPO", i.e. 2,2,6,6-tetramethylpiperidini-1-oxy free radical. Thus, the oxidized forms of the nitroxyl radicals, N-oxoammonium ions, act as direct oxidants in the oxidation of the target cellulose molecule, while a main oxidant is used to bring oxygen to the series of reactions and convert the nitroxyl compound back to the oxidized form. .
    [0004] It is known to oxidize primary alcohols to aldehydes and carboxylic acids through "TEMPO" using sodium hypochlorite as the main oxidant (eg Anelli, PL; Biffi, C; Montanari, F.; Quici, S.; J. Org. Chem. 1987, 52, 2559). To improve the yield in the oxidation of alcohols to carboxylic acids, a mixture of sodium hypochlorite and sodium chlorate was also used (Zhao, MM; Li, J.; Mano, E.; Song, ZJ; Tschaen, DM; Org. Synth. 2005, 81, 195).
    [0005] A procedure for catalytically oxidizing cellulose to native cellulose fibers through "TEMPO" using sodium hypochlorite as the main oxidant (oxygen source) and sodium bromide as the activator is also known (Saito, T. et al.; Cellulose; Cellulose Nanofibers Prepared by TEMPO-Mediated Oxidation of Native Cellulose, Biomacromolecules 2007, 8, 2485-2491). The primary hydroxyl groups (C6-hydroxyl groups) of cellulosic β-D-glucopyranose units are selectively oxidized to carboxylic groups. Some aldehyde groups are also formed from primary hydroxyl groups. When the thus obtained oxidized cellulose fibers are disintegrated in water, they provide a stable transparent dispersion of individualized cellulose fibrils 3 to 5 nm in width, i.e. nanofibrillated cellulose (NFC) or "nanocellulose".
    [0006] The selectivity of oxidation is important so that the chemicals used are not consumed in undesirable side reactions. Selectivity can be defined as the ratio of carboxylic groups formed to the main consumed oxidant.
    [0007] Usually the catalytic oxidation is done in LC (low consistency of 1 to 4%) to get a good mixture. Especially at the beginning of the reaction, efficient mixing is important, because the reaction initially proceeds quickly after starting the addition of NaClO. However, in this consistency range, production costs are actually higher because more chemicals are needed because of side reactions, and water consumption is high. The required size of the appliance will also be larger due to the large volumes of treated water. Raising consistency has not been considered a viable alternative because the energy demand would be too high to ensure efficient mixing by stirring. Intensive mixing also tends to raise the temperature of the reaction medium above the ideal range.
    [0008] The use of sodium bromide as activator is preferred because it accelerates the reaction. For example, WO01/29309 recommends using 3 parts by weight of NaBr to 4 parts of NaOCI. In the series of reactions, the bromide ion acts as an oxygen mediator between the main oxidant and the nitroxyl radical by oxidation to hypobromite and reduction back to the bromide.
    [0009] The use of bromine compounds in the oxidation reaction is problematic due to environmental concerns. Sodium bromide is generally used in the reaction mixture in relatively large amounts and it is difficult to remove bromide residues from the final cellulose product. Bromine compounds also accumulate in process water. Furthermore, the use of bromine on an industrial scale is undesirable. Using large amounts of sodium bromide causes equipment corrosion problems. Bromine compounds are generally recognized as hazardous to health, eg bromate that is formed as a result of side reactions is suspected to be carcinogenic. Invention Summary
    [00010] It is an aim of the invention to provide a method to effectively and selectively oxidize the C-6 hydroxyl groups of cellulose.
    [00011] It is another object to provide a method to produce nanofibrillar cellulose.
    [00012] The selectivity can be increased by carrying out the oxidation in medium consistency, that is, to an initial consistency of the cellulosic raw material that is superior to that normally used. The pulp consistency is above 6%, more preferably equal to or above 8%, and most preferably in the range of 8 to 12% by weight. Within the last mentioned range, the ideal consistency appears to be in the 9 to 11% range. Under the reaction conditions, medium consistency pulp behaves, contrary to what might be expected, like a low consistency pulp, and mixing can be achieved in a simpler way without compromising the reaction efficiency.
    [00013] The mixture in medium consistency is carried out by circulating the reaction medium (mixing the catalyst, cellulosic raw material, oxidant and other substances in a liquid vehicle). Circulation of the reaction medium, for example, by a pump makes it possible to mix the reaction medium with lower energy input, and overheating is avoided due to intensive agitation. The reaction temperature can thus be more easily maintained within a range not exceeding 40°C. The temperature is preferably kept at the ideal level of 25 to 35°C.
    [00014] Cooling can be improved as a result of the circulation loop, where the reaction medium flows out of its main volume. Cooling can occur through the effect of surrounding ambient temperature or additional cooling during the flow of reaction medium in the circulation loop.
    [00015] The circulation of the reaction medium can also be used in dosing the various reactants in the reaction medium, because they can be at least partially dosed in the circulation flow of the reaction medium.
    [00016] Furthermore, by a proper choice of activator, the nitroxyl radical can be activated to the oxidized state without the use of bromide. In the medium consistency oxidation process, the heterocyclic nitroxyl radical is preferably activated by chlorine dioxide. According to another alternative, the heterocyclic nitroxyl radical can be activated by a tertiary amine.
    [00017] The main oxidant in the reaction is hypochlorite. Chlorine dioxide is used as the activator and hypochlorite, eg sodium hypochlorite (NaClO), as the main oxidant at neutral or basic pH. The oxidation reaction is preferably carried out to the desired degree of conversion in this single step by circulating the reaction medium simultaneously through the circulation loop.
    [00018] It is also possible to carry out the conversion in a two-step process where, in a second step, the pH is made acidic and the remaining cellulose aldehyde groups are oxidized to carboxylic groups by chlorite, for example, sodium chlorite (NaClO2 ). By using the two-step method in the activation of ClO2, the selectivity can be further improved and the total oxidation time from hydroxyl to carboxylate can be made shorter. However, when the reaction is carried out at a higher consistency than usually, harmful side reactions to the fibrous material are lessened, cellulose breakage is avoided, and the DP value is better retained. Thus, the one-step reaction is sufficient to retain the advantageous properties of the final fibrous product, and changing reaction conditions and reagents can be avoided when using the method.
    [00019] After the cellulose is subjected to oxidation at medium consistency, it can be processed into a final cellulose product. When the starting material is plant-derived pulp, especially wood, the cellulose exists in the form of fibers. Fibers containing cellulose in oxidized form are easy to disintegrate by mechanical methods into smaller scale fragments, nanofibrillary cellulose (NFC). The method for forming the cellulose product comprises the first process of catalytic oxidation of the fibrous starting material and the second process of disintegrating the oxidized starting material into nanofibrillary cellulose. Brief Description of Drawings
    [00020] In the following, the invention will be described with reference to the attached drawings, in which Figure 1 shows the general principle of the method in the form of a reaction apparatus, Figure 2 shows a reaction apparatus according to another embodiment, and Figures 3 to 5 show results from some oxidation experiments. Detailed Description of Preferred Modalities
    [00021] In the following description, all percentage values are expressed by weight, unless otherwise indicated. In addition, all given numerical ranges include the upper and lower values of the ranges, if not indicated otherwise.
    [00022] The primary hydroxyl groups of cellulose are catalytically oxidized by a heterocyclic nitroxyl compound, eg 2,2,6,6-tetramethylpiperidini-1-oxy free radical, "TEMPO". Other heterocyclic nitroxyl compounds known to have selectivity in oxidizing the C-6 carbon hydroxyl groups of the cellulose glucose units can also be used, and these compounds are widely cited in the literature. Here below, cellulose oxidation refers to the oxidation of these hydroxyl groups to aldehydes and/or carboxyl groups. It is preferred that the hydroxyl groups are oxidized to carboxyl groups, i.e. the oxidation is complete.
    [00023] Whenever the catalyst "TEMPO" is mentioned in this description, it is evident that all measures and operations in which "TEMPO" is involved apply equally and analogously to any derivative of TEMPO or any heterocyclic nitroxyl radical capable of catalyzing selectively the oxidation of C-6 carbon hydroxyl groups on cellulose.
    [00024] In the following description, catalytic oxidation refers to the oxidation mediated by nitroxyl (as mediated by "TEMPO'') of hydroxyl groups. The catalytic oxidation of fibers or fibrous material, in turn, refers to the material that contains cellulose that is oxidized by nitroxyl-mediated (as "TEMPO''-mediated) oxidation of cellulose's hydroxyl groups.
    [00025] When medium consistency of pulp is used, the selectivity of cellulose oxidation can be improved, because the desired reactions take place in the fiber, while the undesirable side reactions take place in the solution phase. At starting pulp consistencies greater than 6%, cellulose can be oxidized at oxidation levels of 0.5 to 1.4 mmol COOH/g pulp, preferably 0.6 to 1.1 and most preferably 0. 7 to 0.9 with high selectivity. Furthermore, any other oxidation levels mentioned in this description can be obtained at these higher starting pulp consistencies.
    [00026] For the purpose of producing nanofibrillar cellulose (NFC), it was found that the level of oxidation (degree of conversion) of 0.5 to 1.0 mmol of COOH/g of pulp, preferably 0.6 to 0, 95 and most preferably 0.7 to 0.9 was already sufficient for the cellulose fibers to be easily disintegrated into fibrils by mechanical energy. Conventionally, it has been the goal to achieve conversion degrees above 1.0 mmol/g of pulp to produce NFC.
    [00027] Figure 1 shows a reaction apparatus according to a first modality. The apparatus comprises a substantially closed tank reactor 1 and a circulation circuit 2, through which the reaction medium is taken from the tank reactor 1 and returned back to the tank reactor. The flow of medium through circuit 2, which may be a tube of suitable diameter, is carried by a circulation pump 3. Movement of the reaction medium through the circuit will cause sufficient mixing inside the tank reactor. Internal motion stirrers are not needed in the tank reactor or their mixing power may be diminished due to the sufficient mixing effect already obtained by the circulation.
    [00028] Feed channel 4, through which the tank reactor 1 is initially filled with the reaction medium, can also be used to dose the chemicals initially needed to start the cellulose oxidation reaction. The feed pump is the feed channel denoted 5. After the reaction is complete, product is withdrawn through a product line 6 connected to circulation circuit 2. Valves needed to control the direction of flows are not shown.
    [00029] The chemicals that can be initially dosed in the reaction medium in feed channel 4 are the activated heterocyclic nitroxyl compounds (arrow A) and the initial dose of the main oxidant, preferably hypochlorite, which is the source of oxygen (arrow B ). As the reaction proceeds, more main oxidant can be added in circulation circuit 2 (arrow C) and pH control by adding alkaline agent can also be achieved through circulation circuit 2 (arrow D) to maintain the pH of the reaction medium in the desired range.
    [00030] The circulation circuit will also cool the reaction medium as it flows along the tube in close proximity to the ambient temperature (ambient temperature) outside the tube. Additional cooling can be provided to circulation circuit 2 by a heat exchanger 7. Tank 1 reactor itself does not need to be a tank equipped with a cooling jacket, but may be of simpler wall construction.
    [00031] All constituents are fed into the tank reactor so that the reaction medium is at an average consistency of above 6%, more preferably equal to or greater than 8%, and most preferably in the range of 8 to 12% when starts the oxidation process.
    [00032] It is advantageous to add the main oxidant, such as hypochlorite, continuously as the oxidation of cellulose proceeds to avoid excessive concentrations that can cause undesirable side reactions.
    [00033] After reaching the desired degree of conversion, the reaction medium is withdrawn from the reactor through product line 6. The fibers containing the oxidized cellulose are separated from the reaction medium, and the reaction medium is possibly reused . Regeneration measures making it possible to reuse at least some of the constituents of the reaction medium are not described here in greater detail. The fibers are washed to remove remaining chemicals and further processed, especially for NFC.
    [00034] Figure 2 shows another modality of the reaction apparatus. As the reaction medium was taken to circulation circuit 2 at the bottom of tank reactor 1 and returned to the top of the reactor in the mode of Figure 1, the medium flow is now reversed (output to circuit 2 through the top and return from circuit 2 through the bottom). Reference numbers indicate parts with similar function as in Figure 1. Reactor 1 is a plug-flow type reactor, which can be provided with static mixers inside the reactor. There is no separate feed channel, but circulation loop 2 can be used to feed the initial constituents of the reaction medium and the required chemicals (main oxidant and alkaline agent) as the oxidation proceeds. After the reaction is complete, the final steps are the same as in Figure 1.
    [00035] The mixing concepts of the reaction apparatus in Figure 1 and 2 are based on the unexpected observation that the mixing of chemicals in the reaction medium and the properties of the modified pulp make mixing at medium consistency easier than with the normal pulp. So reactors that don't apply as much energy (and increase the slurry temperature) are not needed. Chemical reactions change the viscosity of the pulp to such an extent that mixing in the LC reactor (low consistency) can be used. Probably, too, the high salt concentration in the medium consistency range facilitates mixing.
    [00036] When the fibers are of higher consistencies, their separation of the liquid phase from the reaction medium is easier, and washing is also simpler and easier. If the modified (oxidized) cellulose fibers are disintegrated into fibrils to produce nanofibrillar cellulose, this can be done in greater consistency. As the ratio of fibers to liquid is higher, reuse of the liquid reaction medium is easier because of smaller volumes of liquid to be handled. Catalyst recovery forms the liquid medium for reuse purposes is also easier due to the smaller volumes.
    [00037] Although auxiliary mixture in the form of agitation inside the reaction tank can be used, it can be said that the main proportion of the input of mixing energy to the reaction medium is due to circulation. In practice, the output of the circulation pump is greater than the output of the agitator motor if auxiliary agitation is used.
    [00038] In the following, some reaction procedures are given as examples. However, the method is not limited to the given reaction schemes, but can be used in all reactions where the cellulose in the fibers is catalytically oxidized using the nitroxyl-mediated oxidation of cellulose hydroxyl groups and which can be used in cellulose apparatus. reaction of Figures 1 and 2 on medium consistencies of the pulp.
    [00039] According to a preferred embodiment, chlorine dioxide is used as the activator of the heterocyclic N-nitroxyl compound. The main oxidant is hypochlorite. After the desired degree of conversion has been achieved using these reagents, the reaction medium can be removed from the reactor, the fibers can be separated and further treated. The oxidation process can also be a two-step process where, in the first step, the nitroxyl catalyst is activated with chlorine dioxide and hypochlorite is used as the main oxidizer. The reaction proceeds rapidly and partially produces aldehyde groups. The pH in the first stage is preferably between 7.5 and 8.5, these values included, but a wider range, from 6 to 10, can also be used. Compared to other activation methods, activation with ClO2 improves oxidation selectively in a surprising way.
    [00040] When the first stage has proceeded so that a desired degree of conversion is reached, the first stage is stopped. The partially oxidized cellulose can be washed and the second step is carried out in a reaction medium where the pH is clearly on the acid side, about 1.5 to 4, preferably 2 to 3. Preferably the second step is carried out at a pH below of 3. The end point of the first step can be chosen according to the consumption of the main oxidant or any other mode. Alternatively, the pH of the first-stage reaction medium can be lowered directly to the second-stage pH range at the stop point.
    [00041] When the pH is lowered, chlorite, eg NaClO2, is added to the reaction medium. In this second step, the remaining aldehyde groups are rapidly oxidized to carboxyl groups with chlorite as the main oxidizer. Dimethyl sulfoxide (DMSO) can be used in the reaction medium in the second step to eliminate the formation of hypochlorite from chlorite.
    [00042] Usually the first step is stopped when the carboxylate content of 0.6 to 1.0 mmol/g of pulp is reached. The second step increases the carboxylate content upon completion of the oxidation.
    [00043] If the partially oxidized cellulose is washed between steps, the reaction medium is withdrawn from tank 1 reactor, as described above, and the new reaction medium containing the partially oxidized cellulose in the first step is fed to the reactor of tank. The second oxidation step can take place in a similar manner as the first step.
    [00044] By the combination of the first and second steps, the overall reaction of hydroxyl groups to carboxyl groups is fast with good selectivity. Activation of the nitroxyl radical (eg "TEMPO" radical) to the oxidized form by ClO2 and other oxidation of C6 hydroxyl groups of pulp by hypochlorite as the main oxidant is a selective and rapid reaction if all available hydroxyl groups are not oxidized . Residual aldehydes can be converted to carboxylates by the other acid stage (the second step). The acid stage at the end is preferable also in the sense that the oxidized pulp is easier to wash under acidic conditions.
    [00045] The reaction scheme of the first step is given below in scheme 1. Chlorine dioxide is needed only for the conversion of the catalyst from radical form to the active oxidized form.
    Scheme 1. TEMPO-catalyzed bleaching-oxidation of alcohols using chlorine dioxide as activator
    [00046] The conversion of residual aldehydes into carboxyl groups by oxidation in the second step stabilizes the oxidized cellulose. The reaction scheme is shown below.
    Scheme 2. Chemical oxidation of aldehyde to carboxylic acid by chlorite. Chlorite is in the form of chlorous acid (HClO2, pKa 1.96) under acidic conditions. Chlorous acid oxidizes the aldehyde groups of cellulose to carboxylic acid groups. A typical pH range for this reaction is 2 to 4.
    [00047] The temperature in the first step can be between 20 and 50°C and in the second step between 20 and 80°C, preferably 40 and 80°C. The ideal temperature for the second stage is about 50°C. However, due to the tendency of hypochlorite to decompose, the ideal first step temperature is not more than 40°C, preferably between 25 to 35°C, which is a good compromise of high reaction rate and low consumption of hypochlorite and can be facially obtained by reaction arrangements of Figures 1 and 2 at medium consistencies of the starting pulp.
    [00048] According to another modality, cellulose is oxidized in medium consistency catalytically by using hypochlorite as the main oxidizer and tertiary amine as cocatalyst. The likely route is shown in the following scheme 3 (the heterocyclic nitroxyl catalyst is represented by R'2NOH in its reduced form and R'2N+O in its oxidized form). Bromide is also not needed in this process.Alcohol Oxidation• RCH2OH + R'2N'O Φ RCH2ON'(OH)R'2• RCH2ON'(OH)R'2 Φ RCHO + R'2NOHChloramonium Formation• RR'R" N + HOCl Φ RR'R”N'Cl + H2ORTEMPO reoxidation • R'2NOH + RR'R”N'Cl Φ R'2NOCl + RR'R”N + H+• R'2NOCl Φ R'2N+O + Aldehyde Cloxidation• RCHO + HOCl Φ RCH(OH)OCl• RCH(OH)OCl Φ RCO2H + ClScheme 3. TEMPO-catalyzed bleaching-oxidation of alcohols using amine as cocatalyst.
    [00049] The method is a one-step process where all reactants to achieve oxidation are in the same reaction medium. However, oxidation selectivity is greater when the main oxidant, NaClO, is added in portions. The amine cocatalyst can also be added in portions during the reaction time, which increases the selectivity of the oxidation reaction. The pH used is slightly basic, 8 to 9.5. However, any pH value between 7 and 10, these values included, can also be used.
    [00050] The reaction using the amine as cocatalyst can be carried out at room temperature or slightly elevated temperature, in the range of 20 to 50°C, preferably 25 to 35°C, in the absence of added bromide.
    [00051] Suitable tertiary amines are hexamethylenetetramine, 1,4-diazabicyclo[2,2,2]-octane (DABCO) and quinuclidine. However, the invention is not limited to the use of these amines as cocatalysts. Other suitable amines, especially suitable cyclic amines can be used.
    [00052] The method of catalytically oxidizing cellulose at medium consistency using the reaction arrangements exemplified by Figures 1 and 2 is not, however, limited to oxidizing chemicals and activators expressly mentioned above.
    [00053] The reaction medium in all the methods described above is preferably water where the reactants and raw materials can be dissolved or dispersed.
    [00054] In the present application all results shown and calculations made, whenever they are related to the amount of pulp, are expressed on a dry pulp basis.
    [00055] In general, cellulose oxidized to the medium consistency of the pulp can be selectively oxidized to a desired degree of conversion other than complete conversion, but a conversion where it can be mechanically processed, as described later, without loss of material. The conversion achieved at the end of the process (in one step or two steps) is 0.5 to 1.4 mmol COOH/g pulp, preferably 0.6 to 1.1 mmol COOH/g pulp, the most preferably 0.7 to 0.9 mmol COOH/g pulp.
    [00056] The dosage of hypochlorite in cellulose, to achieve the above mentioned conversions, can be from 1.7 to 5 mmol/g of pulp, preferably 2.2 to 2.7 mmol / g of pulp.
    [00057] In all the modalities described above, catalytic oxidation can be carried out without the use of bromide. Sodium bromide, which is conventionally used as an activator and cocatalyst because of the faster reaction rate and high oxidation degree, can be avoided in the catalytic oxidation process according to yet another modality. Conventionally, the ideal pH when using sodium bromide is 10. However, side reactions occur at this pH which cannot be avoided even at the relatively fast reaction rate. The level of DP (degree of polymerization) will decrease considerably, which decreases the strength and gel-forming characteristics of NFC.
    [00058] Thus, according to yet one modality, the non-bromine catalytic oxidation with the heterocyclic nitroxyl radical as a catalyst in the medium consistency of the pulp can be performed by using carefully defined conditions with respect to pH and temperature. The reaction is carried out at neutral or slightly alkaline pH, in the range of 7 to 9, and at room temperature or slightly elevated temperature, in the range of 20 to 50°C, preferably 25 to 35°C, in the absence of alkali metal halide added. Selectivity (fewer C2 to C3 reactions) is improved, and bromine compounds are avoided. The slower rate of oxidation reaction due to the lower pH is compensated for by temperature, which does not increase side reactions as with the higher pH. Chlorine oxide or any other activator can be used in place of alkali metal halide in the first catalytic oxidation step with hypochlorite as the main oxidant using the above conditions of pH and temperature. The second step of completing the oxidation is not necessarily necessary, but if the residual aldehyde groups are to be oxidized to carboxyl groups, it is preferably carried out by using chlorite as an oxidizer and protective substances to avoid unwanted side reactions in the second step, as explained above.
    [00059] Thus, in order to produce NFC, it was found that the level of oxidation (degree of conversion) of 0.5 to 1.0 mmol of COOH/g of pulp, preferably 0.6 to 0.95 and most preferably 0.7 to 0.9 is already sufficient for the cellulose fibers to be easily disintegrated into fibrils by mechanical energy. To reach this level, the one-step oxidation process (only the first catalytic oxidation step, not taking into account the catalyst activator) is usually sufficient. However, it is also possible to complete the oxidation in the second step by oxidizing the residual aldehydes to carboxyl groups to obtain cellulose with the above mentioned oxidation levels indicated as COOH/g of pulp.
    [00060] When the consistency is greater than that conventionally used (above 6%, more preferably equal to or greater than 8%, and most preferably in the range of 8 to 12%), the selectivity of cellulose oxidation can be further improved , because the desired reactions occur in the fiber, while the undesirable side reactions occur in the solution phase. At these starting pulp consistencies, the cellulose may be oxidized at the aforementioned oxidation levels of 0.5 to 1.0 mmol COOH/g pulp, preferably 0.6 to 0.95 and most preferably 0. 7 to 0.9, either in a one-step oxidation process or using the second step to complete the oxidation. In addition, any other oxidation levels mentioned in this description can be obtained at these starting pulp consistencies greater than is common (average consistencies), either in a one-step oxidation process or using the second step after the first step in the dispositions of reaction of Figures 1 and 2.
    [00061] At relatively low oxidation levels above 0.5 to 1.0 mmol COOH/g pulp, preferably 0.6 to 0.95 and most preferably 0.7 to 0.9, it is possible to obtain a Stronger gel, when fibers are disintegrated into fibrils, because less e-elimination occurs. Thus, a lower degree of oxidation reduces chemical expenditures and helps to produce a product with improved strength.
    [00062] The fibrous starting material, which can be pulp of vegetable origin, especially wood (softwood pulp or hardwood, for example, bleached birch pulp) and where the cellulose molecules are oxidized in one of the methods described above , it is easy to disintegrate into a nanofibrillar size, nanofibrillar cellulose or NFC.
    [00063] The term "nanofibrillar cellulose" refers to a collection of isolated cellulose microfibrils or bundles of microfibrils derived from cellulose raw material. Microfibrils typically have a high aspect ratio: the length can exceed one micrometer while the numerical mean diameter is typically below 200 nm. The diameter of microfibril bundles can also be larger, but usually smaller than 1 µm. Smaller microfibrils are similar to so-called elementary fibrils, which are typically 2 to 12 nm in diameter. The dimensions of the fibrils or fibril bundles are dependent on the raw material and the disintegration method. Nanofibrillar cellulose may also contain some hemicelluloses; the amount is dependent on the plant source. Mechanical disintegration of oxidized cellulose raw material is carried out with appropriate equipment such as a refiner, crusher, homogenizer, mechanical device to remove colloidal material, friction crusher, ultrasonic sonicator, fluidizer such as microfluidizer, macrofluidizer or fluidizer type homogenizer.
    [00064] NFC prepared from raw material with oxidized cellulose with the above methods has excellent gelling ability, which means that it forms a gel at a low consistency in an aqueous medium. When the oxidized pulp is ground to a consistency of about 1 to 4% in an aqueous medium, a clear gel consisting of microfibrils in water (NFC gel) is obtained.
    [00065] In any of the above oxidation processes, the carboxylate content of 0.9 to 1.2 mmol of COOH/g of starting pulp (in dry material), preferably 1.0 to 1.1 mmol of COOH /g of pulp is desirable so that gel formation as a result of mechanical disintegration is easy. However, as described above, carboxylate contents below 1.0 mmol are already sufficient to produce NFC and they are preferred if gel strength is preferred.
    [00066] Before the oxidized pulp is disintegrated to produce the NFC, the pH of the medium is adjusted to 7 to 10, preferably 7 to 9, and most preferably to 7 to 8.5, which decreases the energy required.
    [00067] The obtained NFC gel is characterized by shear thinning behavior. The average diameter of the microfibrils is 2 to 20 nm, preferably 2 to 6 nm, and the average length is in the range 0.3 to 5.0 µm, preferably 0.5 to 2 µm. Turbidity is below 70, preferably 20 to 60 NTU (0.1% concentration, nephelometric measurement). Measured at a concentration of 0.5% in water, the gel has zero shear viscosity of 10,000 to 50,000 Pa.s, preferably 20,000 to 50,000 Pa.s if the gel strength properties of NFC, and elastic limit of NFC are preferred. 8 to 40 Pa, preferably 10 to 30 Pa.
    [00068] Below, some experiments are described that should not be considered limiting. Oxidations in medium consistency
    [00069] Some oxidations were performed with an MC mixer at a consistency of 10% and some with an MC pulper at a consistency of 11%. Oxidation to a high consistency is, in theory, more selective, because the desired reactions take place in the fiber and the undesirable side reactions take place in the solution phase. In practice, it has been possible to reduce the amount of TEMPO catalyst and chlorine dioxide in relation to the amount of fiber dosed by increasing consistency. In the applicants' tests, no problems were found in performing oxidations with TEMPO at increased consistencies to medium consistencies. Typical reactions given in the prior art are carried out at a consistency of 1%, and no greater than 4%. Figure 3 shows that oxidation selectivity (carboxylic acids formed by consumed hypochlorite) is improved when consistency is increased over a low consistency range, 1 to 4%.
    [00070] Table 2 shows oxidation results at a consistency of 10% (MC mixer). During oxidation, an MC mixer does not provide a matched mixture for mixing with a Buchi reactor (consistency 1 to 4%). Also, NaClO dosage and pH regulation are less precise. Oxidation is also good at a consistency of 10%, and even better results can be obtained by using a device with more precise chemical dosing and pH regulation. Thus, the results in medium consistency are promising. Table 3 shows oxidations performed with a Buchi reactor at a consistency of 4%. Two TEMPO derivatives are also included: 4-methoxy-TEMPO and 4-acetamido-TEMPO. On the basis of the tests, it can be said that chlorine dioxide can be used to activate not only TEMPO but also TEMPO derivatives. The dosage of TEMPO can also be decreased (pulp 149 to 150) so that the selectivity of the oxidation is maintained. What is essential in optimizing catalyst dosing at a lower level is optimizing the NaClO/NaOH feed simultaneously during oxidation. It is evident that the derivatives of TEMPO and other conditions in table 3 can also be used at medium consistencies.Table 2. Oxidations of TEMPO activated with chlorine dioxide with an MC mixer at a consistency of 10%.


    [00071] In yet a series of tests, TEMPO oxidations of activated chlorine dioxide were performed in slurry MC at pulp consistencies of 6 to 11%. Temperature (25-35°C), pH (7-8) and NaClO addition were manually adjusted during oxidation. Most of the experiments were carried out by adding 2.3 mmol NaClO/g pulp. The results are shown in the following table 4.Table 4. Oxidations of MC pulper at high consistencies. Selectivity means the COOH / hypochlorite molar ratio. Some of the hypochlorite oxidizes the OH groups to aldehydes, but only the COOH-groups/NaClOconsumed ratio is shown.

    [00072] The oxidation selectivity of TEMPO activated with chlorine dioxide, as a function of TEMPO dosage and pulp consistency (6-10%) from the above experiments, is also shown in Figure 4, with rounded consistency values. The maximum selectivity value (formation of added COOH/NaClO groups) is 0.5 due to reaction stoichiometry. 2 mol of NaClO are consumed in the formation of 1 mol of COOH in cellulose because the formation of the COOH group from the hydroxyl group occurs via the aldehyde intermediate.
    [00073] According to these results, it is evident that a greater pulp consistency increases the oxidation selectivity of TEMPO activated with chlorine dioxide. The imperfection of these experiments (manual pH and temperature control) does not interfere with these phenomena. The ideal oxidation conditions according to this result are 10 to 11% pulp consistency and 0.03 to 0.04 mmol TEMPO / g pulp.
    [00074] The reaction conditions can be further improved by using the arrangements shown in Figures 1 and 2, by using the circulation of the reaction medium through the circuit as the main source of energy of the mixture.
    [00075] Some factors affect the oxidation efficiency, especially selectivity, and applicable also for the oxidation of cellulose at medium pulp consistencies using the reaction arrangements described here, are briefly discussed below.
    [00076] Oxidation selectivity can be improved by pumping NaClO at a low rate into the reactor during oxidation. It was found that the reaction rate does not depend on the concentration of HOCl in the reaction mixture, but is constant when a sufficient amount of hypochlorite is present in the reaction. The phenomenon behind the improved selectivity is the tendency of NaClO to decompose when the pH decreases. Decomposition of NaClO is stronger if the HOCl content in the solution is high during oxidation. In a standard reaction, all the hypochlorite is added at once. HOCl is decomposed to dichlorine monoxide (Cl2O) which is a volatile compound. Dichlorine monoxide is further decomposed to chlorate (-ClO3) in a reaction with hypochlorite.
    [00077] The oxidation of C6 hydroxyl groups of cellulose is faster at the beginning of the process when you have several free reactive groups left. As the number of reactive groups decreases, the oxidation rate becomes smaller and a significant change occurs when the number of free reactive groups (amorphous cellulose and part of crystalline cellulose) is very small and the oxidation is directed towards the crystalline cellulose. . Thus, oxidation proceeds primarily via degradation of crystalline cellulose. Figure 5 shows the acid value (mmol COOH per g pulp) of TEMPO oxidations activated with chlorine dioxide as a function of hypochlorite dosage in a one-step process. The figure shows that up to the oxidation level of 0.9 mmol/g of pulp, the 1-step method is efficient as for the consumption of the main oxidant, hypochlorite.
    [00078] Among the amorphous C6 OH groups, 83 to 98% are easily accessed; the corresponding figure in the crystal ranges is 10 to 15%. The graph in Figure 5 shows that cellulose can be easily oxidized in the acid value range of 0.8 to 0.9 mmol COOH per g of pulp. Thereafter, the reaction rate becomes lower and NaClO consumption increases and viscosity decreases as a result of polymer degradation. The acid value range 0.8 to 0.9 can be maintained as an ideal target for selective oxidation. When a lower reaction rate and higher temperature are applied, the aldehyde content remaining in the product after step 1 is typically <0.2 mmol per g of pulp, which is clearly lower than in a typical reaction where the level is between 0.2 and 0.35 mmol per g of pulp. This is likely due to the lower reaction rate, where there is also more time for the oxidation reactions of aldehydes to carboxylates to take place. NFC Production Example
    [00079] The oxidized pulp sample (0.82 mmol COOH pulp / g) was fibrillated using "Atrex" disperser, which is a device that subjects the pulp to impacts from opposite directions at a high frequency, consisting of concentric cylindrical rotors with passageways of channel flow formed by spaced impact blades.
    [00080] Four passes through the device were used. Gel properties of nanofibrillary celluloses were measured using rheometer and turbidity with turbidometer.
    [00081] The properties obtained were: zero shear viscosity 18,000 Pa.s, elastic limit 22 Pa and turbidity 24 NTU. turbidity measurement
    [00082] Turbidity can be measured quantitatively using optical turbidity measuring instruments. There are several commercial turbidometers available to quantitatively measure turbidity. In the present case, the method based on nephelometry is used. The turbidity units of a calibrated nephelometer are called Nephelometric Turbidity Units (NTU). The measuring device (turbidometer) is calibrated and checked with standard calibration samples, followed by measurement of the turbidity of the diluted NFC sample.
    [00083] In the method, a sample of nanofibrillar cellulose is diluted in a liquid, preferably in water, at a concentration below the gel point of said nanofibrillar cellulose, and the turbidity of the diluted sample is measured. Said concentration where the turbidity of nanofibrillary cellulose samples is measured is 0.1%. The mean value and standard deviation are calculated from the results obtained, and the final result is given as units of NTU. HACH P2100 turbidometer, with a 50 ml measuring vessel, was used for turbidity measurements. rheometric measurement
    [00084] The NFC was diluted with deionized water to a concentration of 0.5 and 200 g of the mixture was homogenized with a Buchi mixer (B-400, max 2100 W, Buchi Labortechnik AG, Switzerland) for 3 x 10s.
    [00085] The viscosity of NFC dispersions was measured at 22°C with a traction-controlled rotary rheometer (AR-G2, TA Instruments, UK) equipped with a narrow-space blade geometry (diameter 28 mm, length 42 mm) in a cylindrical sample cup having a diameter of 30 mm. After loading the samples into the rheometer, they were left to stand for 5 min before the measurement was started. Uniform-state viscosity was measured with a gradually increasing shear stress (proportional to applied torque) and shear rate (proportional to angular velocity) was measured. The reported viscosity (=shear stress/shear rate) at a given shear stress was recorded after reaching a constant shear rate or after a maximum time of 2 min. The measurement was stopped when the 1000 s-1 shear rate was exceeded.
    权利要求:
    Claims (30)
    [0001]
    1. Method for catalytic oxidation of cellulosic pulp, characterized in that it comprises: - activating a heterocyclic nitroxyl catalyst by means of an activator, - carrying out the catalytic oxidation of cellulosic pulp in the presence of a heterocyclic nitroxyl catalyst and a main oxidant acting as a source of oxygen in a reactor in a reaction medium that is of average consistency of cellulosic pulp, which is above 6%, - during the oxidation of the cellulosic pulp, mix the reaction medium comprising the cellulosic pulp in consistency above 6% in the reactor, where mixing the reaction medium comprises: removing the reaction medium from the reactor through a circulation circuit; and return the reaction medium back to the reactor.
    [0002]
    2. Method according to claim 1, characterized in that the reaction medium is in the average consistency of cellulosic pulp in the range of 8 to 12%.
    [0003]
    3. Method according to claim 1, characterized in that at least part of the main oxidant is added to the circulation of the reaction medium.
    [0004]
    4. Method according to claim 1, characterized in that chlorine dioxide or tertiary amine is used as the activator of the heterocyclic nitroxyl catalyst.
    [0005]
    5. Method according to claim 1, characterized in that hypochlorite is used as the main oxidant.
    [0006]
    6. Method according to claim 1, characterized in that it further comprises oxidizing the cellulosic pulp to a desired level in two steps by - using chlorine dioxide as the activator and hypochlorite as the main oxidant in a first catalytic step, e- use of chlorite as an oxidizer completing the oxidation in a second step, where the pH is lower compared to the first step.
    [0007]
    7. Method according to claim 6, characterized in that, during the first step, the pH is from 6 to 10 and, during the second step, the pH is from 1.5 to 4.
    [0008]
    8. Method according to claim 5, characterized in that the catalytic oxidation is carried out at pH 7 to 9 and at a temperature of 20 to 50°C.
    [0009]
    9. Method according to claim 1, characterized in that the oxidation is carried out at a level of 0.5 to 1.4 mmol of COOH/g of pulp.
    [0010]
    10. Method according to claim 1, characterized in that, after oxidation, the oxidized cellulosic pulp is further treated.
    [0011]
    11. Method according to claim 1, characterized in that the cellulosic pulp subjected to oxidation is cellulose as a fibrous raw material.
    [0012]
    12. Method according to claim 1, characterized in that it further comprises adding a pH control agent to the circulation of the reaction medium.
    [0013]
    13. Method according to claim 6, characterized in that, during the first step, the pH is from 7.5 to 8.5 and, during the second step, the pH is from 2 to 3.
    [0014]
    14. Method according to claim 5, characterized in that the catalytic oxidation is carried out at pH 7 to 9 and temperature from 25 to 35°C.
    [0015]
    15. Method according to claim 1, characterized in that the oxidation is carried out at a level of 0.6 to 1.1 mmol of COOH/g of pulp.
    [0016]
    16. Method according to claim 1, characterized in that the oxidation is carried out at a level of 0.7 to 0.9 mmol of COOH/g of pulp.
    [0017]
    17. Method according to claim 10, characterized in that it comprises-performing the catalytic oxidation of cellulose in fibrous raw material, in order to obtain fibrous material containing oxidized cellulose, and- disintegrating the fibrous raw material containing the oxidized cellulose nanofibrillar cellulose.
    [0018]
    18. Method according to claim 1, characterized in that the method takes place in the absence of a bromine compound.
    [0019]
    19. Method according to claim 1, characterized in that during the oxidation of cellulosic pulp, the reaction medium is at a temperature not exceeding 40°C.
    [0020]
    20. Method according to claim 1, characterized in that the main oxidant is continuously added to the reaction medium during the oxidation of the cellulosic pulp.
    [0021]
    21. Method for producing a cellulose product, characterized in that it comprises- subjecting the fibrous starting material to oxidation by the method as defined in claim 1, in order to obtain oxidized fibrous material, and- disintegrating the oxidized fibrous raw material.
    [0022]
    22. Method according to claim 21, characterized in that the oxidized fibrous raw material is disintegrated into nanofibrillar cellulose.
    [0023]
    23. Method according to claim 22, characterized in that the nanofibrillar cellulose fibrils have an average diameter of 2 to 20 nm and an average length of 0.3 to 5 μm.
    [0024]
    24. Method according to claim 22, characterized in that the nanofibrillar cellulose has turbidity below 70 NTU (nephelometric turbidity units), as measured at 0.1% concentration in water.
    [0025]
    25. Method according to claim 22, characterized in that the nanofibrillar cellulose has zero shear viscosity of 10,000 to 50,000 Pa.s and elastic limit of 8 to 40 Pa as measured at 0.5% concentration in water.
    [0026]
    26. Method according to claim 22, characterized in that the carboxylate content of the oxidized cellulose is at least 0.6 mmol of COOH/g of pulp.
    [0027]
    27. Method according to claim 21, characterized in that the fibrous starting material is fiber obtained from plant material.
    [0028]
    28. Method according to claim 22, characterized in that the nanofibrillar cellulose has a turbidity between 20 to 60 NTU (nephelometric turbidity units), as measured at 0.1% concentration in water.
    [0029]
    29. Method according to claim 22, characterized in that the nanofibrillar cellulose has a zero shear viscosity of 20,000 to 50,000 Pa.s and an elastic limit of 10 to 30 Pa, as measured at 0.5% concentration in water .
    [0030]
    30. Method according to claim 22, characterized in that the carboxylate content of the oxidized cellulose is 0.7 to 1.4 mmol of COOH/g of pulp.
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    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    JPS463901Y1|1967-12-21|1971-02-10|
    CA1261896A|1985-12-09|1989-09-26|Grace M. Donnelly|Computer assisted laboratory notebook kit|
    JP4074680B2|1997-03-12|2008-04-09|ダイセル化学工業株式会社|Cellulose derivative and method for producing the same|
    JP2002536563A|1999-02-15|2002-10-29|キラムアクチボラゲット|Method for oxygen pulping lignocellulosic material and recovering pulping chemicals|
    US6716976B1|1999-02-24|2004-04-06|Sca Hygiene Products Zeist B.V.|Process for selective oxidation of cellulose|
    WO2000050462A1|1999-02-24|2000-08-31|Sca Hygiene Products Gmbh|Oxidized cellulose-containing fibrous materials and products made therefrom|
    US6379494B1|1999-03-19|2002-04-30|Weyerhaeuser Company|Method of making carboxylated cellulose fibers and products of the method|
    DE19945757A1|1999-09-24|2001-03-29|Philips Corp Intellectual Pty|X-ray detector|
    DE19953591A1|1999-11-08|2001-05-17|Sca Hygiene Prod Gmbh|Metal-crosslinkable oxidized cellulose-containing fibrous materials and products made from them|
    ES2201998T3|2000-04-25|2004-04-01|Sca Hygiene Products Zeist B.V.|OXIDATION OF POLISACARIDS WITH NITROXILS.|
    US6540876B1|2000-05-19|2003-04-01|National Starch And Chemical Ivnestment Holding Corporation|Use of amide or imide co-catalysts for nitroxide mediated oxidation|
    US6821383B2|2001-03-28|2004-11-23|National Starch And Chemical Investment Holding Corporation|Preparation of modified fluff pulp, fluff pulp products and use thereof|
    US20030051834A1|2001-06-06|2003-03-20|Weerawarna S. Ananda|Method for preparation of stabilized carboxylated cellulose|
    US6919447B2|2001-06-06|2005-07-19|Weyerhaeuser Company|Hypochlorite free method for preparation of stable carboxylated carbohydrate products|
    US20050028953A1|2003-08-05|2005-02-10|Severeid David E.|Methods for making carboxylated pulp fibers|
    US7001483B2|2003-08-05|2006-02-21|Weyerhaeuser Company|Apparatus for making carboxylated pulp fibers|
    US20050121160A1|2003-12-08|2005-06-09|Sca Hygiene Products Ab|Process for the separation of organic nitrosonium and/or hydroxylamine compounds by means of cation exchange resins and recovery and oxidation processes based thereon|
    EP1541590A1|2003-12-08|2005-06-15|SCA Hygiene Products AB|Process for the oxidation of hydroxy compounds by means of nitroxy compounds|
    US20050121159A1|2003-12-08|2005-06-09|Sca Hygiene Products Ab|Process for the oxidation of hydroxy compounds by means of nitroxy compounds|
    SE0403222L|2004-12-30|2005-11-08|Kvaerner Pulping Tech|Method for oxygen delignification of cellulose pulp at high pressure in several steps|
    AT501929B1|2005-05-17|2007-04-15|Dsm Fine Chem Austria Gmbh|Selective oxidation of primary alcohols comprises reacting copper with a ligand e.g. pyridine; adding 2,2,6,6-tetramethylpiperidin-1-oxyl and sodium hydroxide; introducing oxygen or air and adding the primary alcohol|
    EP2022802B1|2007-08-10|2017-03-22|Dow Global Technologies LLC|Nanoparticles from slightly oxidised cellulose|
    US8992728B2|2007-11-26|2015-03-31|The University Of Tokyo|Cellulose nanofiber, production method of same and cellulose nanofiber dispersion|
    JP5351417B2|2007-12-28|2013-11-27|日本製紙株式会社|Cellulose oxidation method, cellulose oxidation catalyst, and cellulose nanofiber production method|
    EP2226414B1|2007-12-28|2014-12-03|Nippon Paper Industries Co., Ltd.|Processes for producing cellulose nanofibers, cellulose oxidation catalysts and methods for oxidizing cellulose|
    WO2009084556A1|2007-12-28|2009-07-09|Suncorporation|Image display device|
    JP2009209218A|2008-02-29|2009-09-17|Univ Of Tokyo|Method for producing functional cellulose bead, and the functional cellulose bead|
    CN101952237B|2008-03-12|2014-01-08|重庆华邦制药有限公司|Bromide-free TEMPO-mediated oxidation of the primary alcohol in carbohydrate under two-phase conditions|
    JP2009068014A|2008-09-19|2009-04-02|Toppan Printing Co Ltd|Water-soluble oxidized chitin and its producing method|
    JP5649578B2|2009-08-25|2015-01-07|国立大学法人 東京大学|Method for hydrophilic treatment of cellulose fiber and method for producing hydrophilic cellulose fiber|
    EP2511346B1|2009-12-11|2016-09-07|Kao Corporation|Composite material|
    JP2011184475A|2010-03-04|2011-09-22|Toppan Printing Co Ltd|Manufacturing method for oxidized cellulose, manufacturing method for oxidized cellulose dispersion liquid, and oxidized cellulose dispersion liquid|
    JP5617289B2|2010-03-18|2014-11-05|凸版印刷株式会社|Cellulose membrane and laminate material using the same|
    JP2011219551A|2010-04-06|2011-11-04|Asahi Kasei Fibers Corp|Method for oxidizing cellulose-structured material|
    WO2012115590A1|2011-02-24|2012-08-30|Innventia Ab|Single-step method for production of nano pulp by acceleration and disintegration of raw material|
    JP2012188472A|2011-03-08|2012-10-04|Kao Corp|Method for producing polyuronic acid salt|
    JP5179616B2|2011-03-30|2013-04-10|日本製紙株式会社|Method for producing cellulose nanofiber|
    EP2706072B1|2011-05-02|2015-09-09|Kao Corporation|Method for producing alkali cellulose|
    WO2012161708A1|2011-05-25|2012-11-29|Empire Technology Development Llc|Treating lignocellulosic materials|
    FI125707B|2011-06-09|2016-01-15|Upm Kymmene Corp|A process for the catalytic oxidation of cellulose and a process for preparing a cellulose product|
    CN103797182B|2011-09-12|2016-05-04|郡是株式会社|The manufacture method of hydrophiling cellulose fibre|
    CN103827146B|2011-09-30|2016-09-07|日本制纸株式会社|Cellulose nano-fibrous manufacture method|
    US8641863B2|2011-09-30|2014-02-04|Weyerhaeuser Nr Company|Catalytic carboxylation of cellulose fibers in a continuous process with multiple additions of catalyst, secondary oxidant and base to a moving slurry of cellulose fibers|
    JP5846860B2|2011-11-04|2016-01-20|グンゼ株式会社|Method for producing hydrophilic cellulose fiber|
    EP2826792B1|2012-03-14|2022-01-05|Nippon Paper Industries Co., Ltd.|Method for producing anion-modified cellulose nanofiber dispersion|
    CN102675475B|2012-05-24|2014-08-13|东华大学|Method for preparing fibrilia carboxylation cellulose nanowhiskers|
    CN102776594A|2012-07-10|2012-11-14|东华大学|Cellulose fiber-supported nano silver antibacterial material and preparation method thereof|
    CN102787444A|2012-08-18|2012-11-21|东华大学|Preparation method of porous network structure fiber membrane of nano cellulose/silicon dioxide|
    JP6015232B2|2012-08-23|2016-10-26|日本製紙株式会社|Method for producing oxidized cellulose and cellulose nanofiber|
    US9328459B2|2013-03-29|2016-05-03|Weyerhaeuser Nr Company|Multi-stage catalytic carboxylation of mercerized cellulose fibers|
    FI127002B|2013-07-29|2017-09-15|Upm-Kymmene Corp|A process for the catalytic oxidation of cellulose and a process for preparing a cellulose product|
    FI127246B|2013-09-02|2018-02-15|Upm Kymmene Corp|A process for the catalytic oxidation of cellulose and a process for preparing a cellulose product|FI127526B|2012-11-03|2018-08-15|Upm Kymmene Corp|Method for producing nanofibrillar cellulose|
    WO2015007953A1|2013-07-16|2015-01-22|Stora Enso Oyj|A method of producing oxidized or microfibrillated cellulose|
    FI127002B|2013-07-29|2017-09-15|Upm-Kymmene Corp|A process for the catalytic oxidation of cellulose and a process for preparing a cellulose product|
    FI125715B|2013-12-11|2016-01-29|Upm Kymmene Corp|Method for recovering the catalyst|
    EP3161087A1|2014-06-26|2017-05-03|UPM Specialty Papers Oy|A release liner comprising nanofibrillar cellulose|
    FI126398B|2014-12-18|2016-11-15|Upm-Kymmene Corp|Method for chemical testing|
    FI20146116A|2014-12-18|2016-06-19|Upm-Kymmene Corp|Method and apparatus for controlling cellulosic catalytic oxidation|
    FI125884B2|2014-12-22|2019-03-29|Upm Kymmene Corp|Treating nanofibrillar cellulose hydrogel at eleveted temperature|
    FI125883B|2014-12-22|2016-03-31|Upm Kymmene Corp|Treatment of a catalytically oxidized hydrogel of nanofibrillar cellulose|
    JP6619576B2|2015-07-24|2019-12-11|大王製紙株式会社|Method for producing cellulose nanofiber|
    AT518624B1|2016-04-25|2018-10-15|Applied Chemicals Handels Gmbh|Process for the preparation of a dry strength agent, in particular of glyoxylated polyacrylamide|
    CN106589141B|2016-12-27|2019-06-21|杭州协合医疗用品有限公司|A kind of preparation method of new oxycellulose|
    JP2020037650A|2018-09-04|2020-03-12|日本製紙株式会社|Oxidized cellulose nanofiber and oxidized cellulose nanofiber dispersion liquid|
    FR3105224A1|2019-12-23|2021-06-25|Institut Polytechnique De Grenoble|Catalytic oxidation process for cellulose pulp|
    法律状态:
    2018-03-06| B06F| Objections, documents and/or translations needed after an examination request according [chapter 6.6 patent gazette]|
    2018-03-13| B06F| Objections, documents and/or translations needed after an examination request according [chapter 6.6 patent gazette]|
    2018-03-20| B06I| Publication of requirement cancelled [chapter 6.9 patent gazette]|Free format text: ANULADA A PUBLICACAO CODIGO 6.6.1 NA RPI NO 2462 DE 13/03/2018 POR TER SIDO INDEVIDA. |
    2020-02-27| B06U| Preliminary requirement: requests with searches performed by other patent offices: procedure suspended [chapter 6.21 patent gazette]|
    2021-06-08| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|
    2021-07-27| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 13/12/2013, OBSERVADAS AS CONDICOES LEGAIS. |
    优先权:
    申请号 | 申请日 | 专利标题
    FI20126306|2012-12-13|
    FI20126306A|FI126847B|2012-12-13|2012-12-13|A process for the catalytic oxidation of cellulose and a process for preparing a cellulose product|
    PCT/FI2013/051166|WO2014091086A1|2012-12-13|2013-12-13|Method for catalytic oxidation of cellulose and method for making a cellulose product|
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