CS222679B2 - Method of boiling the ligno-cellulose materials - Google Patents

Abstract

Method of batch lignocellulose materials wherein the ligno-cellulosic material is cooked in a mixture of water and 1 to 4 volumes of aliphatic alcohol with no more than 3 carbon atoms per 1 volume of water containing a metal salt and optionally a small amount of acid reactant at a temperature of 130 to 210 ° C for at most two hours, using 4% by weight parts of boiling liquor per weight part of lignocellulosic material, loosened the cellulose fibers are then removed from the binding liquor the alcohol is evaporated from the boiling liquor and separating the remaining boiling liquor lignin and sugars, which is characterized by the fact that the aqueous alcoholic solution contains from 0.001 to 1.0 moles of magnesium chloride or nitrate, calcium or barium or sulfate magnesium or mixtures thereof and a strong mineral acid in 0.000 5 to 0.008 normal concentration.

Description

The invention relates to a process for batching lignocellulosic materials.

SUMMARY OF THE INVENTION The present invention provides a process for batching lignocellulosic materials, wherein the lignocellulosic material is boiled in a mixture of water and 1-4 volumes of aliphatic alcohol having no more than 3 carbon atoms per volume of water containing a metal salt and optionally a small amount of acidic material at 130 to 210 ° C. for a maximum of two hours using 4 parts by weight of cooking liquor per part by weight of lignocellulosic material, the loose cellulose pulp is then separated from the cooking liquor, the alcohol is evaporated from the cooking liquor and lignin and sugars are separated from the remaining cooking liquor characterized in that the aqueous alcohol solution used as the cooking liquor contains 0.001 to 1.0 moles of magnesium, calcium or barium chloride or nitrate or magnesium sulphate or mixtures thereof and a strong mineral acid at 0.000 5 to 0.008 normal concentration.

The method is particularly suitable for producing pulp having a low Kappa or Roe number, high fiber strength and cellulose in an almost native, ungraded state. Importantly, the process of the invention is equally suitable for gymnosperm and angiosperm wood, as well as for lignocellulosic agricultural wastes under careful brewing under the above conditions.

With the current lack of energy and chemicals, emphasis is placed on batch efficiency and perfect chemical recovery. The new batch methods are intended to be effective in removing lignin in order to shorten the batch, the batch being at the same time moderate enough to achieve near-theoretical fiber yield and to quantitatively obtain dissolved by-products. Delignification must, as far as possible, be perfect to prevent low fiber bonding strengths and to reduce the amount of bleaching chemicals needed when mine is producing fully white paper. Furthermore, a good batch requires perfect fiber loosening. The delignification must therefore cover both the cementation layers of the fibers - the central lamella - consisting of the lignin carbohydrate matrix and the cell walls of the matrix containing lignin and hemicelluloses in different proportions.

Such efficient delignification results in a low proportion remaining on the sieve and the cooking chips require little, if any, mechanical mixing to fully open, thus saving operating energy and fiber length.

- · nd, in wood hydrolysis processes in aqueous mixtures or in aqueous organic solvent mixtures containing unbuffered or unmodified acid catalysts at top, at 165 to 210 ° C, the cellulose is attacked so rapidly that even before the lignin and hemicellulose components are dissolved from the cell walls to significantly break down cellulose. Although relatively weak acids, such as docarboxylic organic acids, are used as the catalyst, the disintegrated fibers have a degree of cellulosic polymerization lower than in the native state, so paper sheets made from these pulps have insufficient tear strength, punch strength and insufficient tear. length for industrial purposes.

Advantages of well known processes include very short batch times and considerable yields of soluble lignin and dissolved sugars, but it remains a requirement in the known cellulosic fiber disintegration processes while maintaining almost all polyglucan fractions while maintaining native cellulosic fiber strength at an acceptable low lignin content.

The invention also relates to a process for producing high-yield pulp having a low residual lignin content to improve fiber bonding and filament formation in a paper sheet and to reduce the consumption of bleaching chemicals in the manufacture of fully bleached papers.

Furthermore, it is desirable to prevent damage to cellulose by the action of the water-miscible organic solvents used in the process of the invention, which are effective in delignification and do not attack carbohydrates.

A further significant improvement of the process of the invention results from the choice of an inexpensive mild catalyst which is a salt having the unique property of producing slightly acidic solutions in aqueous alcohols, contributes to the release of acidic protons into the system by cation exchange with lignin and carbohydrate functional groups, and protects cellulose from attack acidic protons at high temperature. Substantially reduced acidity further eliminates the need to use highly acid resistant digesters.

The invention also relates to a process for the production of pulp in which water and air are not substantially polluted.

One known method, which also does not pollute the environment, is the Kleinert batch process. It is described, for example, in U.S. Patent Nos. 1,856,567 and 3,585,044 and in German Laid-Open Patent Application DAS No. 2,644,55. The only chemical used in this process is alcohol, which can be recovered and recycled, and a small amount of acidic or basic substances. However, it has the disadvantage that the pH of the cooking liquor must be adjusted to at least 8 so that the pH of the waste liquor is 4 to 7 in order to prevent the cellulose obtained from being disturbed by the organic acids released from the lignocellulosic material during the batch. However, delignification proceeds relatively slowly at these pH values. In addition, the rapid evaporation of alcohol from the waste boiling liquor leads to the dissolution of the dissolved lignin in the form of a non-aqueous, dark brown, as if molten, highly plastic mass which is difficult to remove from the digester and which has no industrial use.

In contrast, the process of delignifying or batching the cellulosic material of the invention with the addition of at least one soluble alkaline earth metal salt is substantially shortened and the rapid evaporation of the alcohol from the waste boiling liquor leads to precipitation of the dissolved lignin in powder form; The lignin is then readily separated by filtration or centrifugation and may be used, optionally after recrystallization, as a fuel or as a starting material, for example, for the production of vanillin and other products.

Rapid evaporation yields a major proportion of the alcohol used from the boiling waste liquor and can then be recycled. As the waste liquor is withdrawn from the high-temperature digester, little energy is required for this evaporation.

Thus, the process of the present invention removes the drawbacks of the Kleinert process and other similar processes described, for example, in U.S. Pat. Nos. 3,585,184 and 4,100,016, by batching lignocellulosic materials with a substantially solvent mixture in at least four times the weight of the material to be disbursed. is methanol, ethanol or n-propanol or a mixture thereof in an amount of 20 to 80% to 80 to 20% water, the mixture of alcohol and water containing 0.005 to 1.0 moles of a water and alcohol soluble metal salt selected from the group consisting of the chlorides, sulphates or nitrates of magnesium, calcium or barium or mixtures thereof and the batch is carried out at a temperature of 30 to 210 ° C, preferably 70 to 200 ° C and in particular at a temperature of 95 to 800 ° C for generally 15 up to 90 minutes.

In the case of lignocellulosic materials which are difficult to delignify, and when salts having a low catalytic effect, such as magnesium sulfate, are used, the addition of a small amount of strong acid, preferably with an anion corresponding to the salts used, greatly improves the degree of delignification. until a 0.005 to 0.008 N solution containing a strong acid in addition to the salt catalyst is obtained. Such a method is then highly specific with regard to delignification and CE ¹ are obtained lulózové fibers having a high polymerization degree and a high glucan content.

The process according to the invention is particularly effective when magnesium or calcium chloride or nitrate in a molar concentration of 0.02 to 0.05 and a volume ratio of water to methanol in the solvent mixture of 30 to 70 are used as the salt, the batch being carried out at a temperature of 190 to 200 Deň: 32 ° C.

A batch of coniferous wood, such as spruce, according to the process of the present invention yields a hunin which retains a significant amount of hemioelluloses but has a low residual lignin content and a higher polymerization degree than most pulps obtainable by the kraft batch process; the batch time must be only 30 to 45 minutes to obtain pulp with a Kappa number of 33, a TAPPI viscosity of 0.5 g 20 m Pa.s or a polymerization degree of 1320. The cooked chips are separated into individual fibers by simply suspending in water and obtained the pulp is more easily bleachable from its 50% GE brightness to a desired brightness of 80% and optionally to a higher brightness than the spruce pulp obtained by a kraft batch having a comparable residual lignin content but my much lower starting whiteness, typically 35% GE.

A further disadvantage of the current pulp production processes is that the by-products of the batch significantly interfere with the regeneration of the cooking chemicals, so that this regeneration is not economically attractive. In addition, in the kraft batch process, for example, dissolved sugars are largely converted to saccharinic acid salts, which are of limited importance as industrial chemicals. Similarly, lignin is converted to sulfur derivatives to obtain the necessary degree of solubility for producing low lignin fibers, which means that otherwise partially solvent-soluble lignin is converted to a form that can only be dispersed by alkali. In contrast to the inconvenience of obtaining by-products from a batch of lignocellulose, the process of the invention yields dissolved lignin and sugars, which are separated by rapid evaporation during the batch in the solvent to give relatively concentrated aqueous solutions of sugars otherwise soluble in the solvent lignin in the form of a powder precipitate. The lignin is then separated from the sugars by centrifugation or simple filtration.

The sugar solution obtained is rich in xylan and other hemicelluloses and contains relatively little glucan. Most sugars are in the form of dimers and low molecular weight oligomers which can be readily degraded to simple sugars by secondary hydrolysis in almost quantitative yields. The fact that the sugars are in the form of polymers of low molecular weight sugars protects them from dehydration during the high-temperature batch and makes it possible to obtain higher-soluble sugars.

The lignin precipitated after solvent removal retains its solubility in solvents, which is a highly desirable property for the further chemical treatment contemplated. The molecular weight of such solvent-soluble lignin is determined by gel permeation chromatography and high pressure liquid chromatography, and is from 300 to 12,000, the mean calculated molecular weight being about 3,000.

The lignin thus obtained is readily purified by redissolving in acetone, filtering the acetone solution to remove insolubles, and reprecipitating into water or a non-polar solvent such as diethyl ether, benzene and n-hexane. Other solvents, such as dichloromethane, can also be used as a precipitation solvent, while tetrahydrofuran, dimethylsulfoxide, furfural, methylcellosolve, dioxane, ethanol and acrylonitrile are excellent lignin solvents.

In terms of energy savings, spray drying of its acetone solution at 65 ° C seems to be the most advantageous way to obtain the precipitated lignin. The lignin thus obtained generally has a light color and is in the form of a free-flowing powder.

Fully cooked chips are easily separated into loose fibers by suspending them in a good lignin solvent to remove large amounts of lignin from the fibers. As a rule, a simple washing with a mixture of methanol and water or acetone is sufficient to remove the largest part of the dissolved lignin which is deposited between the fibers. Subsequent washing with water has no adverse effect on the bleachability of the fibers.

A further characteristic of the fibers produced in this way is the possibility of achieving the dewatering normally desired in the pulp, with substantially less energy being spent during the milling. The drainage rate of the obtained spruce pulp 750 requires only 4000 revolutions per PPI mill to obtain a drainage rate of 300 compared to pulp produced by a kraft process with the same initial drainage rate that requires 7,000 to 9,000 revolutions to achieve the same drainage rate, preferably drainage rate 300

The invention is illustrated by the following examples. Percentages are by weight unless otherwise indicated.

Example 1

The cellulose delignification and polydispersity were studied using a 0.16 molar concentration of calcium chloride in a 30:70 mixture of water with methanol, ethanol or n-propanol. The batch is carried out in a stainless steel laboratory pressure vessel of a height of 20 cm and a diameter of 8 cm.

Air-dried wood chips with a moisture content of 8% spruce wood are placed in an amount of 10 g in a digester next to 100 g of the pre-prepared cooking solution. The sealed vessel is heated to 200 ° C in an oil bath and maintained at the boiling temperature for a predetermined period of time. The batch time is selected so as to obtain loose pulp after suspending the cooked chips in 500 ml acetone and stirring the solution at a speed of 800 rpm. At the end of the batch, the vessel is cooled rapidly and the solution is poured off.

The pulp was washed with acetone and then with water and air dried to constant weight. Samples were taken to determine the Kappa number and viscosity, and the final moisture content of the remaining pulp was determined for determination by calculating the pulp yield. Standardized TAPPI methods are used for all tests.

All test results from this batch of batches are shown in Table I. The values clearly show a higher selectivity of methanol as a delignifying agent, which results from the high viscosity of the isolated cellulose pulp.

Table 1

Boiling solution CaClg as catalyst moly Conditions batches Yield pulp % Number Kappa Viscosity TAPPI 0.5 g m Pa.s . Ingredients Volumetric ratio time min i teglota 80:20 0,16 - 30 200 58 63 18 MeOHzHjO 70:30 0.16 30 200 53 55 20.5 60:40 0.16 30 200 51 44 14 80:20 0.16 30 200 54 66 12.5 EtOH: HgO 70:30 0.16 30 200 50 59 8 60:40 0.16 30 200 46 27 Mar: 5 70:30 0.10 25 200 52 75 8 n-propane nolxHgO 70:30 0.10 35 200 48 48 6 70:30 0.10 45 200 46 32 5

Example 2

In the process, wide variations in the molar concentration of the metal salt used are possible under otherwise constant batch conditions. Hardwood can generally be cooked at lower salt concentrations of any catalyst than softwood; for example, a batch of aspen wood with calcium or magnesium or nitrate chloride or nitrate for less than 30 minutes requires 0.005 to 0.10 molar salt concentration, while at the same concentration, magnesium sulfate is required for 45 minutes. Softwood, such as spruce wood, typically requires a higher salt concentration such as 0.05 to 0.20 molar, and in certain cases an improved fiber distribution at 0.5 molar or higher is achieved. Preferred salts are magnesium and calcium chlorides, which are advantageous both at low cost and in that they do not interfere with fermentation processes in which aqueous sugar residues are converted into ethyl alcohol, yeast or other fermentable products. Magnesium sulphate has limited solubility in alcohols, and therefore the concentration of salt that can enter a solution is often limited. In order to compensate for the low salt concentration, magnesium sulfate, a longer batch time than is considered acceptable is required.

Table 2 shows the characteristic pulp yield values and properties of hard aspen wood and soft spruce wood pulp in a batch of aqueous methanol at 200 ° C at a constant wood to boiling ratio of 1:10 (at a water to methanol ratio of 30170).

Table 2

Wood Catalyst Batch time min Yield pulp % Number Kappa TAPPI viscosity 0.5 g m Pa.s Polymerization degree Ingredients moly aspens MgClg 0.01 30 62 27 Mar: 20 May 1 320 MgS0 ₄ 0.05 60 64 35 23 1 410 CaCl ₂ 0.01 30 63 30 21 1 360 CsCl ^ 0.10 25 61 16 »8,7 1 280 MgCl ₂ 0.10 25 59 15 Dec 19 Dec 1 300 BaClg 0.01 30 69 46 poor fiber separation spruce MgClg 0.05 30 59 51 17 1 200 MgCl ₂ 0.10 30 54 29 18 1 270 MgSO ₄ 0.05 60 78 95 poor fiber separation CeClg 0.05 30 66 60 20 May 1 320 CeClg 0.10 30 54 35 19 Dec 1 300 Mg _{(NO3) 2} 0.10 45 57 55 23 1 410 Ca _{(NO3) 2} 0.10 45 58 62 29 1 570

In Table 2, the polymerization stage values are derived from TAPPI viscosity measurements using a nomogram published by Eydholm on page 1120.

Example 3

The other batches were carried out with the same wood species and with the same batches of cooking liquor as in Example 2. The cooking liquor consists of a 70:30 mixture of water and methanol and contains 0.10 moles of calcium chloride as a catalyst. The cooking time and the temperature of the cooking liquor are given in Table 3 below.

Table 3

Wood species Batch Yield pulp % Number Kappa Viscosity TAPPI 0.5 g m Pa.s Polymerization degree time min teglota Spruce 15 Dec 200 72 103 there is no separation fibers 25 200 62 63 28 1 550 35 200 56 46 , 8 1 275 45 200 52 42 15 - 1 160 50 190 63 61 28 1 500 80 190 56 40 23 1 410 Aspens 10 200 90 99 no fiber separation 15 Dec 200 73 61 25 1 450 20 May 200 63 22nd 21 1 360 25 200 6, 16 19 Dec 1 300 40 , 80 63 48 4, 1 750 40 , 90 57 9 2, 1 360

Since each lignocellulosic material has a different composition and character of its lignin-carbohydrate matrix due to the natural growth of the plant material, it is necessary in the method according to the invention to carry out several tests with the material in order to obtain pulp with optimum properties. A certain clue can be given in Table 4, in which the analytical values are seven different types of raw materials, all of which produce high-quality pulps. The pulps are produced under the conditions described above. These conditions must be considered as practical rather than optimal. The table includes the properties of a test sheet of handmade paper after grinding the pulp to a drainage rate 300 according to the Canadian standard, the tests of the handmade paper sheet being carried out as described in the TAPPI standard. The pulps are tested only after washing with acetone to remove dissolved lignin and suspended in water before sieving and processing into paper sheet.

The results of the analysis of sugars, lignin and wood pulp for aspen and spruce wood are shown in Table 4 and Table 5.

Properties of wood pulp in 3: 7 blend of defect and methanol, Properties of handmade paper from washed unbleached pulp, wood-to-lye blend ratio of 1: 10, at variable temperature and at a drainage rate of 300 according to Canadian standard centration calcium chloride i

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Table 5

Species of wood Substrate Yield pulp Residual Viscosity Lignin TAPPX gluc. Carbohydrate composition xyl.gal. Arab. mann. gla. sugars » % E, 5 B d Pa. and % % % %% % % aspens wood 77.4 ’ 19,7 ² 22 ³ 57.9 13 0.5 0,2 3,4 1.0 76.0 pulp 6,, 0 2.1 19 Dec 53.1 3 0.1 feet 2,2 0.06 58.26 lye - 16.3 - 0.4 7 0.5 trace 0.8 0.2 9.1 spruce wood 72.3 26.5 21 49.9 6 ?, 8 1,1 11,9 0.8 7 ', 5 pulp 52 2.9 19 Dec 43.1 2 - 2.5 tracks 47.6 lye - 23.0 - 1.7 1, 4 1 0,6 4,7 0.1 8.9

¹ Holocellulose (lignin free), ² Klason lignin, ³ JayT FeTNa viscosity

The high glucose content of the pulp shows that there has been little, if any, damage to the wood pulp.

Example 4

Since salts tend to react with cation exchange with wood, it was believed that the pulp would contain some salt. Therefore, the pulps of Example 3 were prepared and subjected to a batch in a strong oxidizing agent, after which the samples were diluted with demineralized water. In the resulting solutions calcium and magnesium ions were determined by atomic absorption spectrophotometry. The results are shown in Table 6.

Table 6

Type of cation % in wood % in pulp Wood magnesium 0.021 5 0,010 7 aspens Calcium 0,108 6 0.000 9 magnesium 0,005 2 0,007 7 Calcium 0,065 1 0,001 2 spruce magnesium 0.015 1 0,001 5 Calcium 0,071 2 0,045 3 birch

All batches were performed with 70:30 methanol / water mixtures containing 0.05 M magnesium chloride or calcium chloride hot for 30 minutes. The pulps were washed once with acetone and two portions each with 500 ml of distilled water before drying for analysis.

It is clear from Table 6 that pulps contain even fewer cations than were present in the original wood.

222679 ^{1 0}

Example 1 a d 5

It is known that for rapid complete delignification of an acid-catalyzed aqueous organic solvent mixture, a relatively large number of proton concentrations is required to achieve rapid delignification. The metal salt catalysts of the invention do not appear to be able to generate such a high proton concentration in situ. A moderate drop in pH from 5.8 for a mixture of 70:30 methanol and water containing 0.05 moles of calcium chloride to 4.2 was observed only when the boiling solution was added to the wood chips. The development of such a weak acidic character in salt solutions added to wood chips is well known in the literature.

In some cases, especially with a batch of gymnosperm, the delignificae may be too slow and insufficiently selective, making it difficult to produce pulps with a low residual lignin content. In such cases, it has been found that the initial concentration of protons can be favorably influenced by a small concentration of mineral acid, which generally has the same ion as the salt. Such an acid additive generally affects the overall delignification and hydrolysis of hemicelluloses while cellulose is still well protected from protons by the incrusted lignin, since in its native structure the cellulose is less accessible to acids if solvent swelling is limited by the lignin-hemicellulose matrix.

The activity of the metal salt as a catalyst does not change from that expected in the absence of a mineral acid, i.e. the metal salt acts both as a proton donor and as an important protective agent for cellulose, especially in the later stages of the batch and protecting it against hydrolytic solvolysis. Such a synergistic effect is clearly seen in Table 7. Higher acid concentrations are much more effective in reducing the residual lignin content of the pulp. This is at the expense of a slight decrease in pulp yield without a significant decrease in cellulose viscosity.

Thus, air-dried chips of spruce wood are boiled at a ratio of wood to boiling solution 1:10 of a mixture of 70:30 methanol (water containing the indicated amount of acid and salt as a catalyst. The batch temperature is 200 ° C and the heating time is 7 minutes for each batch and is included at the indicated batch time.

Table 7

Catalyst Acid salt N AT Batch time min Yield pulp % number Kappa Viscosity TA.PPI 0.5 g m Pa.s Polymerization degree h ₂ Sat ₄ 0,003 75 40 45.8 39 3.7 460 MgSO ₄ 0.05 60 78 105 no fiber breakdown H ₂ SO ₄ / MgSO ₄ 40 51 36 9.5 9.0 HCl 0,002 40 ⁷⁰ there is no fiber distribution CeClg 0.05 40 54 44 20 May 1 320 HCl / CaCl ₂ 40 56 58 30 1 600 HCl 0.002 / CaCl ₂ 35 58 57 24 1 440 HCl 0.004 / CaCl ₂ 40 53 37 23 1 420 HCl 0.00 / MgSO ₄ 40 56 51 19.2 1 3,0 HNOj 0.004 45 48 50 4.0 470 Ca / NO3 / g 0.10 45 58 62 29 1 570 HNO 3 0.004 / Ca / NO 3 / g 45 55 37 23 1 420

continuation of Table 7

Catalyst N

Acid M salt

Batch time min

Yield number Kappa TAPPI pulp viscosity 0.5 g% o Pa.s.

Polymerization stage

HNO ₃ 0.002 / Mg / N0 _3/2 45

HCl 0,002 / CaCl, 0,05 aspen wood 25

39 25

450

20 25

450

The description and examples fully illustrate the method of the invention and make it easier for those skilled in the art to use it. Of course, variations and modifications of the above-described methods according to the appended claims are also within the scope of the invention. The advantages of the method according to the invention over the methods known in the art are also illustrated by the following comparative example.

Comparative example

The comparative example illustrates an increase in the delignification rate using alkaline earth metal salts compared to the Kleinert batch process. All batches are performed stationary. The batch at 90 ° C is carried out for 7 minutes, the batch at 200 ° C is carried out for 13 minutes.

According to Kleinert, a preferred lye lye is used in the Kleinert method, which is a mixture of ethanol and water in a 50:50 by volume ratio at an initial pH of 6.0 to 6.5 (see U.S. Pat. 4 and others).

In the batch according to the invention, a mixture of methanol, the batch of the most preferred alcohol, and water in a ratio of 80:20 by volume and calcium chloride at a concentration of 0.05 m is used as the cooking liquor.

All pulps with Kappa numbers above 65 are treated for 5 minutes at 50 ° C with chlorite and then their viscosity is determined.

The results are shown in the following table.

Table 8

Way Wood species Batch temperature Noc: 2 ° C Time min Pulp yield Výpliv TAPPI Kappa number 0.5% ¹ Alpha-Cellulose % after alkaline extraction řýěžek viscosity Pa.s ^-3 Kleinertův aspen 190 60 70.4 - uncooked 90 64.4 58.4 10.1 66 21 - - 120 63.0 53.0 2.3 36 17 - - , 50 58.7 48.7 1.5 33 , 8 40.1 24 According to invention aspen 190 25 68.8 - 3.2 37 42 - - 35 63.6 - 0.4 21 38 47.2 38 40 6,, 0 - - 14 32 - - 50 60.4 - - 10 27 Mar: - - 65 58.5 - - 8.6 24 46.5 28

continuation of Table 8

The wood batch Time Yield buničlny cleaner rejects number TAPPI Alpha ffelulóza ^ZpŮ8 ° ^te P type ^{b lota min} e; ^ i ^kappa 0.5 gvýtěžěk viscosity ^{C. Z} 5S Pa.s ^-3

Klelnert spruce 200 30 82.8 - uncooked 60 70.3 - does not occur : k i department fiber 90 64.1 53.4 33.7 150 - - - 120 59.9 53.0 24.2 110 15 Dec - - 180 56.5 49.1, 13.1 86 13 - - 210 52.3 46.3 6.9 71 11 39 18 260 51.2 44.8 4,5 65 9.7 - - According to Spruce 200 20 May 75.2 4.6 102 38 25 66.8 - 2.9 94 43 - - 35 63.5 - 3.0 87 48 - - 50 61.0 - 1.3 60 42 - - 60 58.6 - 1.0 51 36 44 37 65 57.2 - 0.8 43 35 - - 70 55.1 - - 32 32 - - 80 54.4. - - 25 28.7 - -

The values in the table show that when using the cooking liquor according to the invention, the lignin dissolves substantially faster than using the cooking liquor which Kleinert considers to be advantageous. In addition, it can be inferred from the yield values of alpha-cellulose and the viscosity values obtained with the batch according to the invention that the cellulose is not damaged by the organic acids released during the batch.

Claims (3)

SUBJECT OF THE INVENTION ,. Process for batching lignocellulosic materials, wherein the lignocellulosic material is boiled from a mixture of water and 1-4 volumes of aliphatic alcohol of at most 3 carbon atoms per volume of water containing a metal salt and optionally a small amount of acidic reagent at a temperature of 130 to 210 ° C. two hours using 4 parts by weight of cooking liquor per part by weight of Ugnocellulose material, the loose cellulose pulp is then separated from the cooking liquor, the alcohol is evaporated from the cooking liquor and lignin and sugars are separated from the remaining cooking liquor, characterized in that The alcoholic solution used as boiling liquor contains 0.001 to 1.0 moles of magnesium, calcium or barium chloride or nitrate or magnesium sulphate or mixtures thereof and a strong mineral acid at 0.0005 and 0.008 normal concentration. 2. A process according to claim 1, wherein the alcohol used in the cooking liquor is methanol or methanol. ethanol. 3. A process according to claim 1, wherein the strong mineral acid in the cooking liquor is hydrochloric, sulfuric, phosphoric or nitric acid. Severography, n. P., MOST