Abstract: A method for catalytic oxidation of cellulose using a heterocyclic nitroxyl radical as catalyst, main oxidant acting as oxygen source, and an activator of the heterocyclic nitroxyl radical, comprises—a preliminary activation step of the heterocyclic nitroxyl radical with hypochlorite to activated catalyst, and after the preliminary activation step, a cellulose oxidation step using the activated catalyst and hypochlorite as the main oxidant to oxidize cellulose. In the cellulose oxidation step, fibrous starting material is subjected to the oxidation to oxidize the cellulose, whereafter the oxidized fibrous raw material is disintegrated to nanofibrillar cellulose (NFC).

Abstract: The cellulose nanofiber production method of the present invention comprises an oxidation treatment step for oxidizing native cellulose in a neutral or acidic reaction solution containing an N-oxyl compound and an oxidizing agent that oxidizes aldehyde groups, and a dispersion step for dispersing the native cellulose in a medium following the oxidation treatment step. According to the production method of the present invention, a cellulose nanofiber is provided that has long fibers and demonstrates high strength.

Abstract: A process for making pulp includes providing plant fiber raw material. The plant fiber raw material can be wood fiber or gramineae plant fiber. The plat fiber raw material is cooked to make a pulp. A TEMPO catalytic oxidation system is added to the pulp to oxidize the pulp fiber. The oxidized pulp fiber is then bleached.

Abstract: Cellulose nanofibers are produced using a 4-hydroxy TEMPO derivative by treating a cellulosic material with an oxidizing agent in water in the presence of a cellulose oxidation catalyst containing an N-oxyl compound to prepare oxidized cellulos, and microfibrillating the oxidized cellulose.

Abstract: A pulp production process can produce pulp at high yield without using sodium sulfide and high-temperature/high-pressure conditions if compared with the Kraft process and also collect lignin. Pulp is produced by processing wood chips for hydrophlicization at room temperature, using a dilute caustic soda aqueous solution, selectively partially modifying lignin in dilute nitric acid and digesting the wood chips by means of a dilute caustic soda aqueous solution under the atmospheric pressure. Lignin is agglomerated and sorted out from the isolated black liquor.

Abstract: The present invention relates to a liquid composition which comprises at least one polymer and at least one ionic liquid, the cations of which are derived from polycyclic amidine bases, and a process for isolating cellulose from cellulose-containing sources using at least one such ionic liquid.

Abstract: A process for producing dissolving pulp includes a degumming step using a degumming liquor which includes hydrogen peroxide and ammonia.

Abstract: A continuous and batch system to produce cellulose, native lignin and unicellular protein from any form of vegetation in a closed process. The biomass is mixed in the impregnate solution of nitric acid and/or ammonium hydroxide and water. After a period of time at room temperature and atmospheric pressure the chemical solution is recycled. The biomass is moved to the reactor and heated. Evaporated impregnate is recovered via absorption tower and recycled back to chemical solution. The biomass is moved to an alkaline solution, then cooled to separate pulp from black liquor. The black liquor is pumped to a separation tank and is treated to precipitate lignin. The solution is filtered to separate sweet liquor and lignin. The lignin is dried and the sweet liquor is fermented to produce unicellular protein.

Abstract: The invention relates to a process for treating bleaching liquors from pulping processes based on organic acids. The process is characterized in that inorganic acid, such as nitric acid, phosphoric acid and/or sulphuric acid, is added into a bleaching liquor obtained from the bleaching or a stage closely associated with bleaching, whereby organic acids contained in the bleaching liquor are released into the bleaching liquor. The organic acids are then separated from the bleaching liquor and recycled to the cooking stage to be used as cooking chemicals. The nitrogen-, phosphor- and/or sulphur-containing product thereby produced, from which organic acids have been separated, is recovered to be used as a fertilizer or as raw material for a fertilizer.

Abstract: The invention provides for methods for producing pulp (comprising cellulose) and lignin from lignocellulosic material, such as wood chips. The methods involve acid catalyzed hydrolysis. Lignocellulosic material having a relatively high moisture concentration can be used as the starting material. The lignocellulosic material is impregnated with an acid (preferably nitric acid) and heated. During the heating lignin is depolymerized at relatively low temperatures, and the acid catalyst is distilled off. The acid catalyst can be collected and recycled after impregnation and heating. The lignocellulosic material is then digested in an alkaline solution under heat, dissolving the lignin and allowing the pulp to be removed. Acid is added to the black liquor to precipitate the lignin which is then removed. The resultant amber liquor can be further processed into other ancillary products such as alcohols and/or unicellular proteins.

Abstract: Polysaccharide aldehydes are prepared using selective oxidation involving the use of nitroxyl radical mediated aqueous oxidation with a limited amount of oxidant and defined reaction conditions. These polysaccharide aldehyde derivatives having maximum effective aldehyde and minimal carboxylic acid levels making them especially useful as wet, temporary wet and dry strength additives for paper.

Abstract: A method for fractionating fibrous biomass comprising cellulose, hemicellulose and lignin components to separate said lignin, cellulose and hemicellulose from one another comprises:

Abstract: Pulps or papers, especially chemimechanical or thermomechanical pulps or papers, which still contain lignin, have enhanced resistance to yellowing when they contain an effective stabilizing amount of a hindered amine compound which preferably is a nitroxide, a hydroxylamine or an ammonium salt thereof. This performance is often further enhanced by the presence of one or more coadditives selected from the group consisting of the UV absorbers, the polymeric inhibitors, the nitrones, the fluorescent whitening agents, metal chelating agents, sulfur containing stabilizers, metal salts and diene compounds. Combinations of nitroxides, hydroxylamines or their salts, benzotriazole or benzophenone UV absorbers and a metal chelating agent are particularly effective. Selected derivatives of 1-oxyl-2,2,6,6-tetramethyl-piperidin-4-ol and selected hydroxylamine salts are novel compounds and are surprisingly effective for this purpose.

Abstract: Pulps or papers, especially chemimechanical or thermomechanical pulps or papers, which still contain lignin, have enhanced resistance to yellowing when they contain an effective stabilizing amount of a hindered amine compound which preferably is a nitroxide, a hydroxylamine or an ammonium salt thereof. This performance is often further enhanced by the presence of one or more coadditives selected from the group consisting of the UV absorbers, the polymeric inhibitors, the nitrones, the fluorescent whitening agents, metal chelating agents, sulfur containing stabilizers, metal salts and diene compounds. Combinations of nitroxides, hydroxylamines or their salts, benzotriazole or benzophenone UV absorbers and a metal chelating agent are particularly effective. Selected derivatives of 1-oxyl-2,2,6,6-tetramethylpiperidin-4-ol and selected hydroxylamine salts are novel compounds and are surprisingly effective for this purpose.

Abstract: The present invention relates to a device and method for measuring the bleach requirement and bleachability of pulp in a pulp mill. The invention enables pulp mill operators to better control bleach plants. In one aspect, the invention comprises a system and method for rapid bleaching of the pulp, and measuring the rapid bleached brightness and lignin content of the pulp. In another aspect, the invention comprises an optical system for use in practicing embodiments of this invention.

Abstract: Pulps or papers, especially chemimechanical or thermomechanical pulps or papers, which still contain lignin, have enhanced resistance to yellowing when they contain an effective stabilizing amount of a hindered amine compound which preferably is a nitroxide, a hydroxylamine or an ammonium salt thereof. This performance is often further enhanced by the presence of one or more coadditives selected from the group consisting of the UV absorbers, the polymeric inhibitors, the nitrones, the fluorescent whitening agents, metal chelating agents, sulfur containing stabilizers, metal salts and diene compounds. Combinations of nitroxides, hydroxylamines or their salts, benzotriazole or benzophenone UV absorbers and a metal chelating agent are particularly effective. Selected derivatives of 1-oxyl-2,2,6,6-tetramethyl-piperidin-4-ol and selected hydroxylamine salts are novel compounds and are surprisingly effective for this purpose.

Abstract: A manufacturing process of cellulose solution with low viscosity includes the step of dissolving a cellulose in a mixture solvent which is produced by mixing an additional solvent mixture, N-methylol caprolactom, with a main solvent, N-methyl morpholine oxide. The present invention not only can increase the swelling of the pulp during the dissolving process, but also can lower the viscosity of the cellulose solution that enables the manufacturing process to process at lower temperature and the cellulose solution produced to spin in higher spinning speed. Therefore, the physical property and the quality of the final fiber product are improved by eliminating the problem of cellulose polymerization decay.

Abstract: A method of creating a number of separate product streams from an agricultural waste material, comprising: providing a starting material consisting of an agricultural waste material; hydrolyzing the starting material with an acid solution at atmospheric pressure, and temperatures not exceeding about 100.degree. C., to create an absorbent, hydrolyzed solid residue and a xylose-containing liquor; reserving the xylose-containing liquor; and delignifying the hydrolyzed solid residue with a basic solution, to create a fiber solid residue suitable for use as an absorbent material, and a dissolved lignin-containing solution.

Abstract: Cellulose is effectively oxidized with nitrogen dioxide in a hydrofluoroether solvent.

Abstract: Method of separating the surface layer from the core of a piece of wood is escribed. In it, the surface of the piece of wood is initially pre-damaged or roughened and the piece of wood thus treated is thereafter soaked in water or an aqueous solution until the moisture of the wood in the surface layer is at least 30%. Thereafter, the piece of wood thus pre-treated is subjected to a steam process with steam at a temperature of 120 .degree. to 160 .degree. C. by which the surface layer to be removed is solubilized to an extent sufficient for removal from the piece of wood in a following step.

Abstract: The invention is concerned with a process for the production of a suspension of cellulose in a liquid, aqueous tertiary amine-oxide, wherein shredded cellulose is mixed with the liquid, aqueous tertiary amine-oxide, said process comprising:(A) contacting the shredded cellulose with the liquid, aqueous tertiary amine-oxide, a first mixture being prepared, and(B) spreading this first mixture mechanically as a layer on a surface and transporting it along this surface while intensively being mixed, until a homogeneous suspension is produced which is removed from the surface, wherein(C) measures (A) and (B) are carried out continuously.

Abstract: A method of producing sugars and converting the sugars to ethanol in which particulate biomass resulting from hydrolysis of the hemicellulosic content of the biomass is subjected to enzymatic hydrolysis of the cellulosic content to glucose and fermentation of the glucose to ethanol. The particulate biomass resulting from hydrolysis of the hemicellulosic content of the feed stock is reduced to very fine particle size before enzymatic hydrolysis. The hydrolysis of cellulose and the fermentation of the resulting glucose may be carried out separately or they may be carried out simultaneously. The pentoses and hexoses resulting from hydrolysis of the hemicellulose may be subjected to fermentation separately to produce ethanol or they may be fermented simultaneously with the fermentation of the glucose derived from the cellulose.

Abstract: A plant for the production of cellulose films and fibers includes at least one pulping device for producing a first suspension of pulp in an aqueous amine-oxide solution and a first thin-film treatment apparatus for receiving the first pulp suspension and producing a concentrated pulp suspension. The plant also includes a second thin-film treatment apparatus wherein the concentrated pulp suspension is transformed into a mouldable solution of cellulose and a spinning device connected to the second thin-film treatment apparatus, wherein the mouldable cellulose solution is processed into cellulose films and fibers. A process for the production of cellulose films and fibers according to an amine-oxide process includes the steps of suspending pulp in an aqueous amine-oxide solution to produce a first suspension, concentrating the first suspension, producing a mouldable cellulose solution by heating, and processing the solution to form cellulose films and fibers.

Abstract: A process for the production of a cellulose moulded body, particularly cellulose fibres, characterized by the combination of the measures offeeding a cellulose-containing material into an aqueous solution of a tertiary amine-oxide in order to suspend said cellulose-containing material,removing water from the suspension while intensively mixing it and providing elevated temperature and reduced pressure, until a solution of cellulose is produced andmoulding said solution by means of a moulding device, particularly a spinneret, and introducing it into a precipitation bath in order to precipitate the dissolved cellulose,provided that as said cellulose-containing material, basically shredded waste paper, shredded cellulose-containing fibre assemblies and/or shredded, mechanically and/or chemically broken up annual plants are used.

Abstract: Two stage hydrolysis of lignocellulosic material, conditions during the first stage being such as to hydrolyze or depolymerize the hemicellulosic component without substantial degradation of resulting monosaccharides, conditions during the second stage being such as to hydrolyze the cellulose to glucose without substantial degradation of the glucose. The solids left after first stage hydrolysis are disintegrated mechanically thereby greatly facilitating second stage hydrolysis. Hydrolysis in both stages is preferably accomplished by the use of nitric acid. The pH retention time and temperature in both stages are selected to maximize production of the desired monosaccharide or monosaccharides.

Abstract: A process is disclosed for maximizing the brightness of wood pulps which have been treated with anionic bleaching agents wherein the brightness is enhanced by the use of selected quaternary ammonium compounds.

Abstract: The method solves the problem of delignifying technical cellulose pulp in a selective manner which will result in very low residual contents of lignin in the pulp and a correspondingly high quantity of lignin dissolved in spent liquors, which are recovered in the chemical recovery system of the pulp mill. The method comprises activating liquid-containing lignocellulosic material in the presence of nitrate with a gas that contains nitrogen dioxide, followed by the alkaline delignification of the lignocellulosic material, and measuring the acidity of the liquid accompanying the material on at least one occasion during the activation. The method is characterized in that the acidity of the liquid is measured subsequent to bringing the time derivative of the nitrate concentration of the liquid, expressed as millimols per liter of liquid per minute, to a level beneath +0.

Abstract: A method is disclosed of forming a premix which is suitable for conversion into a cellulosic dope which can be used to produce cellulosic products. The method involves introducing into a mixing chamber predetermined quantities of shredded cellulosic material and a solution of amine oxide at an elevated temperature and stirring the mixture for a period of time by rotating mixer blades within the mixing chamber at a speed of between 40 and 80 r.p.m..

Abstract: In a three-stage process for the delignification of cellulose-containing raw materials, pulping is initially performed with a solution of concentrated aqueous acetic acid at an elevated temperature and under an elevated pressure. The resultant acetic acid-moist pulp is treated in a second stage with the aforementioned pulping solution with the addition of nitric acid and is then washed or extracted with water or with the pulping solution. In a third treatment stage, the thus-obtained acetic acid-moist pulp is treated with an ozone-containing gas.

Abstract: Two stage hydrolysis of lignocellulosic material, conditions during the first stage being such as to hydrolyze or depolymerize the hemicellulosic component without substantial degradation of resulting monosaccharides, conditions during the second stage being such as to hydrolyze the cellulose to glucose without substantial degradation of the glucose. The solids left after first stage hydrolysis are disintegrated mechanically thereby greatly facilitating second stage hydrolysis. Hydrolysis in both stages is preferably accomplished by the use of nitric acid. The pH retention time and temperature in both stages are selected to maximize production of the desired monosaccharide or monosaccharides.

Abstract: A method of bleaching a chemical pulp by adjusting the pH of the pulp to 1.5-3.5, chelating the pulp and then treating the pulp in an N stage with nitric oxide (NO) in the amount of at least 1.5% by weight of the oven dried pulp at a consistency of between 30 and 55% and further treating the pulp in a Z stage with ozone to produce a bleach pulp having a higher viscosity for a given permanganate number compared with a similar pulp bleached without using the N stage.

Abstract: A process for the comminution, in particular defibrillation, and reaction of fibrous materials having a high dry solids content with the addition of a circulating medium, preferably a carrier gas and/or reaction agent, as well as optionally of chemicals. The invention is mainly characterized in that the circulating medium is recycled after leaving the comminuting device, by changing its temperature, and is then recycled to the comminuting device. Another embodiment of the invention is characterized in that the fibrous materials and liquid reaction agent are separated from the carrier gas and reaction agent vapors, which are then recycled back to comminuting device. A plant for carrying out this process is mainly characterized in that the comminuting device and route for recycling and treatment of the circulating medium form a closed system.

Abstract: Two stage hydrolysis of lignocellulosic material, conditions during the first stage being such as to hydrolyze or depolymerize the hemicellulosic component without substantial degradation of resulting monosaccharides, conditions during the second stage being such as to hydrolyze the cellulose to glucose without substantial degradation of the glucose. The solids left after first stage hydrolysis are disintegrated mechanically thereby greatly facilitating second stage hydrolysis. Hydrolysis in both stages is preferably accomplished by the use of nitric acid. The pH, retention time and temperature in both stages are selected to maximize production of the desired monosaccharide or monosaccharides.

Abstract: An improved wood pulping process for the delignification of wood in a solvent wherein the solvent is a supercritical fluid under supercritical conditons and contains a delignification agent such as sodium hydroxide, sodium sulfide and/or sodium bisulfate.

Abstract: An imitation leather product and a process for the preparation of the imitation leather product from natural hemp which comprises the steps of (a) firstly digesting natural hemp fiber with weak alkali solution, (b) secondly digesting with ammonia gas, (c) presoak treating either with methylol urea and ammonium phosphate, or sodium chromate and sulfuric acid, and immediately adding ammonia thereto, respectively, (d) beating with SBR resin and cyclohexylcarboxyl diphenylamino thiazolyl sulfonamide, (e) jetting through a multiple stage fiber jetting device, and soaking in a soaking bath container containing methylphenol and SBR resin.

Abstract: A process is provided for activating cellulose pulp using NO and/or NO.sub.2 plus oxygen gas in the presence of nitric acid, added in an amount within the range from about 0.1 to about 1.0 gmole per kg of water accompanying the cellulose pulp at a temperature within the range from about 40.degree. to about 120.degree. C. for a time at an activating temperature of 40.degree. to 50.degree. C. of from 15 to 180 minutes, at from 50.degree. to 90.degree. C. of from 5 to 120 minutes, and at higher temperatures of from 1 to 10 minutes, followed by washing, and delignifying bleaching in an alkaline medium with or without oxygen gas and/or peroxide.

Abstract: A process is provided for the activation and delignification of cellulose pulp, which comprises:(1) subjecting chemical cellulose pulp to activation by reaction with nitrogen dioxide in the presence of water at a temperature within the range from about 20.degree. to 120.degree. C., while(a) separating gas containing at least 1.2 mml nitrogen oxides, including NO, per liter of gas determined at 25.degree. C. and calculated as nitrogen, reacting nitrogen oxides in said withdrawn gas with oxygen gas in an amount within the range from about 10 to about 200 mole percent, calculated on the amount of NO present, and recycling the reacted gas to the activation; and(b) separating gas containing less than 0.4 mml nitrogen oxides, including NO, per liter of gas determined at 25.degree. C. and calculated as nitrogen from the cellulose pulp and removing said gas from the process; and(2) delignifying the activated cellulose pulp.

Abstract: A process is provided for reducing carbohydrate losses in the sulphate pulping of wood using sodium hydroxide and sodium sulfide, by pretreating the wood in the presence of water with oxygen gas and nitrogen oxide such as NO.sub.2 and/or NO and/or polymeric oxides and double molecules thereof, for example, N.sub.2 O.sub.4 or N.sub.2 O.sub.3, for from about 3 to about 110 minutes at a temperature within the range from about 25.degree. to about 100.degree. C., the amount of nitrogen oxide charged, calculated as monomers, being within the range from about 0.05 to about 1 kilomole per 1000 kg bone-dry wood, resulting in one or several of the following advantages: an improved yield of pulp, an improved viscosity, and a reduced requirement for bleaching chemicals in any subsequent bleaching stages.

Abstract: A process is provided for producing nitrogen oxides from aqueous waste cellulose pulp liquors containing nitrogen compounds including oxygen linked to nitrogen in the molecule, which includes initiating an autocatalytic reaction generating nitrogen oxide in a liquid phase comprising aqueous waste cellulose pulp liquor containing nitrogen compounds including oxygen linked to nitrogen in the molecule at a temperature within the range from about 40.degree. to about 180.degree. C. and at an acid pH within the range from about 0 to about 5 in the presence of nitrate ion NO.sub.3.sup.- in a concentration calculated as nitrogen within the range from about 0.2 to about 5 grams moles per kilogram of water and of lignin in a weight ratio lignin:water within the range from about 0.001:1 to about 1:1; and then continuing the autocatalytic reaction while maintaining a gas phase in contact with the liquid phase having a partial pressure of nitrogen oxide within the range from about 0.

Abstract: A process of treating fibrous ligno-cellulose material to form defibered chemical cellulose pulp suitable, for example, for the manufacture of paper and paperboard and dissolving pulp and to treat defibered ligno-cellulose material to produce basic animal feed or packaging and building boards.The process is based on the nitration and dissolving of the lignin component of the cellulose material either in an alkaline solution or with a two step operation in which the nitration can be in an acid stage comprising the step of submerging the fiberous ligno-cellulosic material in aqueous nitric acid having an HNO.sub.3 concentration in the range of about 0.125 to 9 weight percent, followed by an alkaline stage to dissolve out the nitrated lignin from the fibrous structure. In the production of chemical pulp or animal feed the lignin containing solution (black liquor) is separated from the cellulose material.

Abstract: A process is provided for delignifying bleaching lignin-containing cellulose pulp which comprises:(1) activating cellulose pulp by reacting the pulp at a pulp consistency within the range from about 20% to about 60% and at a temperature within the range from about 20.degree. to about 130.degree. C. with a gas comprising NO.sub.2 and oxygen in the presence of water, sodium nitrate in an amount of at least 0.15 g mole per kg of water, and optionally nitric acid;(2) washing the activated pulp with water or an aqueous solution; and(3) treating the activated washed pulp with an aqueous alkaline solution at a temperature within the range from about 70.degree. to about 170.degree. C., optionally in the presence of oxygen gas until the lignin content of the pulp is so reduced that the Kappa number of the pulp is within the range from about 10 to about 60% of the Kappa number of the pulp entering the activating stage (1).

Abstract: Defiberized lignocellulosic material, such as wood, is treated with a liquid carrier containing an oxidizing agent (a per compound, a chlorate or a nitrate), and the wet mat thereof is subjected to pressure, and to heat for a sufficient period of time to cause an oxidative reaction among the fibers resulting in a strong interfiber bond. Where the oxidizing agent is a per compound, the pH of the mixture or lignocellulosic material and per compound is less than 7. Catalysts or other reaction modifying agents are employed if needed. By virtue of the enhanced interfiber bonding effect, paper sheets, such as liner board, which are usually formed of delignified cellulosic material, the fibers of which are highly refined, can be formed totally or partially of less expensive sources of material such as ground wood, semi-chemical or semi-mechanical lignocellulosic pulps without sacrifice of strength.

Abstract: A process for delignifying bleaching cellulose pulp in three stages, an activating stage, and first and second alkaline stages, NO and/or NO.sub.2 and O.sub.2, and optionally HNO.sub.3, being supplied to the water-containing pulp in the activating stage; in the first alkaline stage, alkali being supplied as carbonate, primarily HCO.sub.3.sup.-, with oxygen gas having a partial pressure, on average, of from 0 to 0.2 MPa, the lignin content of the pulp being lowered in this stage so that the Kappa number of the pulp after the stage is from 10 to 60% of the Kappa number of the pulp entering the activating stage; in the second alkaline stage, alkali being supplied as carbonate, primarily CO.sub.3.sup.=, with oxygen gas at a partial pressure, on average, of from 0.1 to 3 MPa.

Abstract: A two-stage oxygen bleaching of chemical cellulose pulp is provided, in which an alkaline oxygen bleaching stage is preceded by a nitrogen dioxide activating stage in which oxygen is added to the activating stage in an amount such that nitrogen monoxide formed as an intermediate during the activation process is consumed, so regulating the amount of oxygen added that when the activation reaction is practically complete, substantially all of the nitrogen dioxide and nitrogen monoxide has been consumed.

Abstract: A process is provided for the bleaching delignification of cellulose pulp with oxygen gas in the presence of alkali, wherein the pulp is first activated with nitrogen dioxide and then washed, preferably with water. The invention is characterized in that the acid solution obtained is used to pretreat the digested pulp subsequent to washing the pulp with waste liquor obtained from the oxygen gas bleaching delignification stage.

Abstract: The process for producing pulp according to the present invention consists in the subsequent steps of an aqueous treatment of a vegetable stock at a temperature within the range of from 110.degree. to 170.degree. C. under a pressure of from 2 to 7 atm.g. for a period of from 0.3 to 4 hours at a weight ratio of the vegetable stock to water of 1:2-4 respectively; a simultaneous impregnation and cooking of said vegetable stock in a solution of nitric acid at a temperature of from 70.degree. to 90.degree. C. for 0.5-3 hours; cooking at a temperature of from 100.degree. to 130.degree. C. under a pressure of from 1 to 4 atm.g. for 0.3-0.5 hour; an alkali extraction of the vegetable stock; decontamination of the gaseous cooking products by mixing thereof with the air in a volumetric ratio of 1:0.5-1 respectively, and treatment with the spent liquor resulting from the stage of alkali extraction.

Abstract: Uronic oxidation of cellulose is achieved by reacting cellulose with aqueous nitric acid containing nitrogen dioxide.

Abstract: A process is provided for the delignification of lignocellulosic material wherein the lignocellulosic material, prior to the delignification, is treated with water or an aqueous solution to remove compounds which catalyze the degradation of carbohydrates and then the delignification is carried out with oxygen and alkali in the presence of a manganese compound to improve the selectivity of the delignification and increase the rate of delignification.

Abstract: Particulate lignocellulosic material, having a moisture content of about 10-80 weight percent, is treated at temperatures below about 50.degree. C. with 2 to 8 weight percent nitric oxide based on the weight of dry lignocellulosic material. Thereafter, said nitric oxide treated material is reacted with molecular oxygen to form nitric acid in situ. This reaction is followed by washing of said material with alkali and extraction of said material with alkali at a temperature above about 140.degree. C. to delignify the lignocellulose and form pulp.

Abstract: A process for the comminution, in particular defibrillation, and reaction of fibrous materials having a high dry solids content with the addition of a circulating medium, preferably a carrier gas and/or reaction agent, as well as optionally of chemicals. The invention is mainly characterized in that the circulating medium is recycled after leaving the comminuting device, by changing its temperature, and is then recycled to the comminuting device. Another embodiment of the invention is characterized in that the fibrous materials and liquid reaction agent are separated from the carrier gas and reaction agent vapors, which are then recycled back to comminuting device. A plant for carrying out this process is mainly characterized in that the comminuting device and route for recycling and treatment of the circulating medium form a closed system.