EA027996B1 - Process for producing cellulose powder - Google Patents

Abstract

The use: cellulose powder can find application in chemical, pharmaceutical, food and other branches of industry. The essence of the invention is as follows: crushed cellulose is treated by soaking with an aqueous sodium pyrosulphate solution, filtered, dried, and after milling flowing cellulose powder with high reactivity is obtained, the powder yield is 99.40 wt.%. The proposed process is environmentally sound.

Description

The invention relates to the chemistry of cellulose, and in particular to a method for producing powdered cellulose, which may find application in chemical, pharmaceutical, food and other industries.

A condensation reaction is known in a cellulose solvent system. In order to accelerate and better dissolve the cellulose in the dimethylacetamide (DMAA) / LiC1 system, cellulose activation is carried out, which consists in heating or boiling the solvent and cellulose system, during which the cellulose is degraded. Cellulose degradation in DMAA or DMAA / L1C1 proceeds according to two independent chemical processes, one of which is associated with slow cleavage of the end groups and the formation of furan structures, and the other process is caused by rupture of cellulose of macromolecules under the influence of Ν, Ν-dimethylketenimine ions, which have an extremely high reactivity electrophilicity and the ability to break the glycosidic bond at a temperature of 80 ° C (1).

The disadvantages of the method is the activation of cellulose by chemical reagents at high temperature and the condensation reaction with the formation of wastewater.

A known method of activation of cellulose by treatment with Lewis acids A1C1 ₃ and T1C1 ₄ in the presence of solvents CC1 ₄ , C ₆ H ₁₄ , C ₂ H ₅ OH, the concentration of Lewis acid in solution is 0.011.5%. After activation, the degree of polymerization of the resulting cellulose powder is 80-120, which is half the value of the limit degree of polymerization for microcrystalline cellulose obtained by classical hydrolysis. It was shown that based on powder cellulose obtained using T1C1 ₄ and having low values of the degree of polymerization, the synthesis of soluble sulfate derivatives with a high degree of substitution is possible (2).

The disadvantage of this method is the activation of cellulose by chemical reagents in the presence of solvents to produce wastewater.

A known method of activation and copolymerization of cellulose is as follows: the pulped cellulose is impregnated with an aqueous solution of potassium persulfate with a concentration of 2.0-4.1 wt.%, Then drying is carried out at a temperature of 100-105 ° C for 60-90 minutes In this case, the fragility of the macromolecular structure of cellulose is maximally increased, and when grinding within 8 ^ 14 min, the macromolecular and fibrous structures are destroyed, which leads to the production of loose activated cellulose powder with a yield of 94.2 wt.%.

The process of copolymerization of activated cellulose powder with acrylic acid is carried out at a temperature of 75 ° C, a reaction time of 60 minutes, with a molar ratio of cellulose: acrylic acid: sodium lauryl sulfate: potassium persulfate, constituting 0.0154: 0.486: 0.011: 0.0037, respectively, the conversion of monomers 97.8 wt.% (3 - prototype).

The disadvantages of the method of activation of cellulose are the use of an expensive oxidizing agent for impregnation of cellulose, a long drying and grinding time of the pulp, and a low yield of activation products.

The objective of the invention is to expand the range of cellulose-containing raw materials and reagents during activation of cellulose, simplifying the technology of activation of cellulose and eliminating wastewater.

The problem is solved by processing waste paper brand MS-1A (hereinafter referred to as cellulose) by treating with an aqueous solution of sodium pyrosulphate for 15-45 minutes, with a molar ratio of water: sodium pyrosulphate: cellulose equal to 22.22: 0.09009-0.1981: 0.0185-0.0216, respectively, by drying at a temperature of 100-105 ° C in the aisles of 60 minutes, followed by grinding to particle sizes of 10-320 μm, the grinding time is 6-10 minutes, the result is a loose cellulose powder with a particle content of a particle size below 10-320 μm is 99.40 wt.%.

When processing crushed cellulose by sorption of an aqueous solution of sodium pyrosulphate with macromolecular and fibrous structures of cellulose and during drying due to crystallization of sodium pyrosulphate, brittleness is maximized and upon grinding, the pulp turns into a loose reactive powder,

The proposed method for the activation of cellulose in comparison with the prototype consists in using cellulose-containing waste paper of the grade MS-1A as the feedstock and to give maximum fragility to the macromolecular structure of the cellulose before grinding it is treated with aqueous solutions of sodium pyrosulphate followed by drying, and the macromolecular and fibrous are destroyed during milling structure with obtaining granular cellulose powder with high reactivity. (According to the prototype, cellulose activation is carried out by impregnation with an aqueous solution of potassium persulfate, and then the cellulose is dried at a temperature of 100-105 ° C for 60-90 minutes. At the same time, the fragility of the macromolecular structure of cellulose is maximized and macromolecular are destroyed during grinding for 8-14 minutes and fibrous structures, this leads to the production of activated loose cellulose powder with a yield of 94.2 wt.%.) The advantage of the proposed method for the activation of cellulose in comparison with the prototype is the use of ma ulatury mark MC-1A and sodium pirosernokislogo activator with good water solubility decrease drying time and pulp mill, pulp yield increase in activated and expanding the range of chemicals to pulp activation.

For a better understanding of the invention, the following are examples.

Example 1. In a liter beaker equipped with a stirrer, 22.22 mol of distilled water, 1.027996 mol, 0.09009 mol of sodium pyrosulphate are charged and the stirrer is turned on at a speed of 60 rpm, and 0.0185 mol of crushed water is added to the resulting aqueous solution of sodium pyrosulphate cellulose. Cellulose treatment is continued for 20 minutes, and then, at a temperature of 100-105 ° C., drying is carried out for 60 minutes, followed by grinding of treated pulp for 10 minutes. The resulting loose cellulose powder is fractionated with sieves.

The molar ratio of water: potassium pyrosulphate: cellulose is 22.22: 0.909009: 0.0185, respectively.

The results of the experiments are presented in table 1.

The quality of sodium pyrosulphate is determined by GOST 4377-77, the composition of waste paper is cellulose GOST 10700-97, GOST 5982-82, the fractional composition of activated cellulose powder is GOST 358473, the viscosity of the aqueous copolymer solution is GOST 1028-81, the degree of drying of the copolymer film is GOST 19007-73 , coating adhesion - GOST 15140-78, sodium lauryl sulfate - TU-06-09-09-09-270-84, acrylamide - GOST 3758-65, potassium sulfate - GOST 4146 -74, the dry residue of the copolymers is determined by the physicochemical method, the hydrogen number solutions is determined by a pH meter.

Example 2. Carries out as in example 1, except that use 26 g (0.11706 mol) of sodium pyrosulphate. The molar ratio of water: sodium pyrosulphate: cellulose is 22.22: 0.11706: 0.0185, respectively.

Example 3. Carried out as in example 1, except that they use 38 g (0.1709 mol) of sodium pyrogenate. The molar ratio of water: sodium pyrosulphate: cellulose is 22.22: 0.1706: 0.0185, respectively.

Example 4. Carried out in example 1, except that they use 44 g (0.1981 mol) of sodium pyrosulphate. The molar ratio of water: sodium pyrosulphate: cellulose is 22.22: 0.1981: 0.0185, respectively.

Example 5. Carried out as in example 1, except that use 3.5 g (0.0216 mol) of sodium pyrosulphate. The molar ratio of water: sodium pyrosulphate: cellulose is 22.22: 0.17109: 0.0216, respectively.

Example 6. Carried out as in example 1, except that the processing time of the pulp is 15 minutes The molar ratio of water: sodium pyrosulphate: cellulose is 22.22: 0.17109: 0.0185, respectively.

Example 7. Carried out as in example 2, except that the grinding time is 6 minutes The molar ratio of water: sodium pyrosulphate: cellulose is 22.22: 0.909009: 0.0185, respectively.

The proposed experiments show that, when the cellulose is treated with an aqueous solution of sodium pyrosulphate, followed by filtration and drying at a temperature of 100-105 ° C, the cellulose acquires maximum brittleness and, when milled, the macromolecular and fibrous structure is destroyed with the formation of a loose cellulose powder with high reactivity.

Below are the results of experiments on the copolymerization of activated cellulose powder with methacrylic acid in the presence of a radical polymerization initiator.

Example 8. In a three-necked reactor equipped with a stirrer, contact thermometer and reflux condenser, load 3.3 mol of distilled water, 0.00925 mol of cellulose powder, 4.44 wt.% Emulsifier (from monomers) sodium lauryl sulfate and 0.1690 mol of acrylamide and include a stirrer. After reaching a temperature of 70 ° C. 2.22 wt.% Initiator of the radical polymerization of potassium persulfate is fed into the reactor. The copolymerization is carried out at a temperature of 75 ° C, the reaction time of 70 minutes

The molar ratio of water: cellulose: acrylamide is 3.33: 0.00925: 0.1690, respectively.

Example 9. Carried out in example 8, except that they use 0.00925 mol of cellulose powder and 0.18319 mol of acrylamide. The molar ratio of water: cellulose: acrylamide is 5.55: 0.00925: 0.18319, respectively.

Example 10. Carried out in example 8, except that they use 0.00925 mol of cellulose powder and 0.18319 mol of acrylamide. The molar ratio of water: cellulose: acrylamide is 5.55: 0.00925: 0.18319, respectively.

The results of the experiments are given in table.2.

The experiments show that, during copolymerization of activated cellulose with a particle size of 10-200 μm with acrylamide, the process proceeds under mild conditions at a temperature of 75 ° C and a reaction time of 70 minutes, the composition of the obtained copolymer has a dry matter content of 1218 wt.%, A viscosity of 1% an aqueous solution of the copolymer is 4.4-5.5 mm ² / s, the conversion of monomers is 97.31 wt.%.

- 2 027996

Table 1

No. Name of reagents Numbers of experiments and their results one 2 3 4 5 6 7 one Taken Distilled water, gr 400 400 400 400 400 400 400 2 Sodium pyrosulphate, gr twenty 26 38 44 38 38 twenty 3 Waste paper MS-1 A, ground gr 3 3 3 3 3,5 3 3 4 Time of processing, min twenty thirty 40 45 40 fifteen twenty 5 Drying at a temperature of 100 = 105 ° C min 90 90 90 90 90 90 90 6 Grinding time min 10 10 10 8 8 10 6 RECEIVED 7 Cellulose powder gr Fractional composition: % 630 μm 9.09 4,57 0.60 1.24 1,58 5.67 13.50 8 320 μm 36.36 40.00 17.58 18.52 19.29 34.24 38.12 200 microns 25.00 20.00 33.33 30.86 32.35 29.00 24.19 100 μm 20.46 20.03 30.31 27.77 24.65 18.21 15.98 50 microns 9.09 15.40 18.18 21.61 22.13 12.88 8.21 nine Cellulose powder yield, % 90.91 95.43 99.40 98.76 98.72 94.33 86.50

table 2

No. Name of reagents Numbers of experiments and their results 8 nine 10 one Taken Distilled water, gr 60 one hundred one hundred 2 Sodium lauryl sulfate, 0.6 0.6 0.6 3 Cellulose powder, including 100 μm 200 microns 320 μm gr 1,5 1,5 1,5 4 Acrylamide gr 12 thirteen thirteen 5 Initiator K2Z2O8, gr 0.3 0.3 0.3 6 Temperature, gr 75 75 75 7 Reaction time, ° C 70 70 70 8 RECEIVED Copolymer aqueous solution, gr 74,4 115.4 115.4 nine Dry matter content % 18.0 12.0 12.0 10 The viscosity of a 1% copolymer aqueous solution, mm ² / s 4.4 5.2 5,0 AND PH number 6.9 7.0 7.9 12 The drying time of the film, hour 5,0 5,0 4,5 thirteen Film adhesion, ball one one one 14 Monomer Conversion, % 96.25 97.31 96.22

LITERATURE

1. Nubgo1uys rgose§§eg§ apb sopbezayop geasyopz ιη Fe ce11i1og § §1uep! §§§1esh MN-sPscheFu ^ seLashMe 1шш с Сопе. Ρΐ.2 YedgabaLop about £ se11i1o§e. Ро1утег., 2003.44, No. 1, p. 7-47 English

2. Abstract of dissertation for the degree of candidate of chemical. Sciences Frolova S.V. (Institute of Chemistry of the Komi Science Center, Ur ORAN, 167610, Komi Republic, Syktyvkar, Pervomaiskaya St., 48) Arkhangelsk State tech. University, Arkhangelsk, 2008, 20 s, ill. Bible 18, Russian

3. Patent No. 015856 EA, IPC С08В 1/00, December 30, 2011

Claims (1)

CLAIM A method of producing cellulose powder, including treating cellulose with an aqueous solution of potassium persulfate, followed by drying and grinding to activate cellulose, characterized in that the raw materials use cellulose-containing waste paper brand MS-1A and before grinding the raw materials are further treated with an aqueous solution of sodium pyrosulphate in a molar ratio of water: sodium pyrosulphate: cellulose equal to 22.22: 0.090-0.1981: 0.0185-0.0216, respectively, followed by filtration, drying at a temperature of 100-105 ° C for 60 minutes and grinding for 610 minutes while macromolecular and destroyed fiber structure to obtain a particulate cellulose powder with particle size of 10-320 microns.