EA019859B1 - Method for cellulose activation - Google Patents

Abstract

The invention relates to cellulose chemistry and associated branches, in particular, to a method of cellulose activation and can be used in chemical, pharmaceutical, food and other industries as a raw material. Cellulose is activated in the following way: ground waste paper of MC-1A grade is processed using aqueous solution of sodium pyrophosphate of 1.0-8.0% concentration, after slurry separation the cellulose mass is dried at 100-105°C during 60 minutes and cellulose content in the processed waste paper is determined. Wherein the cellulose fragility is increased to the maximum and in a milling step macromolecular and fibrous structure is destroyed during 4-8 minutes. The obtained cellulose bulk powder exhibits high reactivity, cellulose fracture content with particles 10-320 mkm constitutes 98.87 wt%. The activated cellulose powder can be used in the process of copolymerization with unsaturated monomers, the obtained copolymer can be used as a thickener and a raw material in a paint and varnish industry as well as in a textile industry.

Description

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

A known method of activation of cellulose. As raw materials, cellulose and sulfuric acid are used. Cellulose at a temperature of 90 ° C for 2 hours is treated with a 5% solution of sulfuric acid, the ratio of cellulose to sulfuric acid is 1:10. The resulting cellulose solution is filtered, neutralized at a temperature of 120-60 ° C, and in the second stage, the temperature is 100-120 ° (1).

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

A known method of activating leafy sulfate cellulose by treating with Lewis acids A1C1 ₃ and T1C1 ₄ in the presence of solvents CC1 ₄ , C ₆ H1 ₄ , C ₂ H ₅ OH, the concentration of Lewis acid in solution is 0.01-1.5%. The degree of polymerization of the obtained cellulose powder is 80-120, which is half the value of the ultimate 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 disadvantages of the method is the activation of cellulose by chemical reagents in the presence of solvents to produce wastewater.

A known method of activating 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 the cellulose is dried 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 minutes, the macromolecular and fibrous structures are destroyed, which leads to the production of free-flowing activated cellulose powder, with a content of powder particles of 200 μm and below, is 94.2 wt.% (3 )

The disadvantages of the method of activation of cellulose are the use for the impregnation of cellulose expensive oxidizing agent, long drying and grinding pulp.

The objective of the invention is to give cellulose fibers maximum fragility to ensure the destruction of the macromolecular and fibrous structures during milling in order to obtain cellulose powder with high reactivity.

The problem is solved by processing crushed (waste paper grade MS-1A according to GOST 10700-97 will hereinafter be called cellulose) pulp 1.0-8.0% aqueous solution of sodium pyrophosphate, for 20-60 minutes at a molar ratio of water: sodium pyrophosphate: cellulose 15.3-16.5: 0.0112-0.0902: 0.0185, followed by filtration and drying at a temperature of 100-105 ° C for 60 minutes, followed by grinding for 4-8 minutes, the obtained loose cellulose powder with a particle content of 10 microns, 100 microns, 200 microns and 320 microns has a high reactivity.

When processing MS-1A brand waste paper with an aqueous solution of sodium pyrophosphate, the waste paper swells and the reagents used in the manufacture of paper (rosin, titanium oxide, etc.) as sludge are dissolved in an aqueous solution of sodium pyrophosphate and separated together with the solution in the form of a precipitate. After separation of the sludge, the cellulose-containing mass is filtered and dried, while the cellulose content is 91.7 weight. %

The use of below 1.0% aqueous solution of sodium pyrophosphate leads to a decrease in the yield of cellulose powder, the maximum yield of activated cellulose is 98.87 wt.%.

The proposed method for the activation of cellulose in comparison with the prototype is that to give maximum fragility to the macromolecular structure of cellulose before grinding, it is treated with an aqueous solution of sodium pyrophosphate followed by drying, and when grinding, the macromolecular and fibrous structure is destroyed to obtain a loose cellulose powder with high reactivity . The content of the main fraction with particle sizes of 10-320 μm is 98.87 wt.%. The proposed cellulose activation process is environmentally friendly. (According to the prototype, the activation of cellulose is carried out with an oxidizing agent potassium persulfate, the drying time is 90 minutes and the grinding time is 8-14 minutes).

The method is as follows. A 1.0-8.0% aqueous solution of sodium pyrophosphate is prepared, then ground pulp with a size of 1.3 x 1.3 cm is treated with an aqueous solution of sodium pyrophosphate for 20-60 minutes at a molar ratio of water: sodium pyrophosphate: cellulose 15.3-16 5: 0.0112-0.0902: 0.0185. The treated cellulose in the drying process at a temperature of 100-105 ° C for 60 min becomes brittle, and when grinding the macromolecular and fibrous structure of cellulose is destroyed. The resulting free flowing cellulose powder is highly reactive.

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

Example 1

In a liter glass equipped with a stirrer, 297 g (16.5 mol) of distilled water and 3 g (0.0112 mol) of sodium pyrophosphate are loaded, the stirrer is turned on at a speed of 60 rpm, 3 g of sodium pyrophosphate are fed into the solution (0, 0185 mol) of pulped pulp for 60 min.

- 1 019859 interfere. Cellulose treated with sodium pyrophosphate is separated and dried at a temperature of 100-105 ° C for 60 minutes. Dried pulp within 8 min of grinding turns into a loose powder, which is divided into 4 fractions of 10, 100, 200 and 320 microns.

The molar ratio of water: sodium pyrophosphate: cellulose is 16.5: 0.0112: 0.0185.

The results of the experiments are given in table. one

The composition of waste paper is determined according to GOST 10700-97, the cellulose composition of GOST 5982-82, GOST 6840-78, the fractional composition of activated cellulose powder GOST 3584-73, the viscosity of an aqueous solution of a copolymer GOST 1028-81, the degree of drying of the film of copolymers GOST 19007-73, adhesion coatings GOST 15140-78, the dry residue of the copolymers is determined by the physicochemical method, the bulk density of the cellulose powder is determined according to GOST 2211-65.

Example 2

Carried out as in example 1, except that using 291 g (16.1 mol) of distilled water, 9 g (0.0338 mol) of sodium pyrophosphate.

The molar ratio of water: sodium phosphate: cellulose is 16.1: 0.0338: 0.0185.

Example 3

Carried out as in example 1, except that using 285 g (15.8 mol) of distilled water and 15 g (0.0564 mol) of sodium pyrophosphate.

The molar ratio of water: sodium pyrophosphate: cellulose is 15.8: 0.0564: 0.0185.

Example 4

Carried out according to example 1, except that using 276 g (15.3 mol) of distilled water and 24 g (0.0902 mol) of sodium pyrophosphate.

The molar ratio of water: sodium pyrophosphate: cellulose is 15.3: 0.0902: 0.0185.

Example 5

It is carried out according to example 2, except that the processing time of cellulose in a solution of sodium pyrophosphate is 30 minutes

The molar ratio of water: sodium pyrophosphate: cellulose is

16.1: 0.0338: 0.0185.

Example 6

Carried out as in example 4, except that the processing time of cellulose in a solution of sodium pyrophosphate is 20 minutes

The molar ratio of water: sodium pyrophosphate: cellulose is

15.3: 0.0902: 0.0185.

Example 7

Carried out according to example 2, except that the grinding time of the dried pulp is 4 minutes

The molar ratio of water: sodium pyrophosphate: cellulose is 16.1: 0.0338: 0.0185.

The experiments show that the treatment of cellulose with an aqueous solution of sodium pyrophosphate, followed by filtration and drying at a temperature of 100-105 ° C, ensures that the cellulose acquires maximum brittleness and, when milled, the macromolecular and fibrous structure breaks down to obtain free-flowing cellulose powder with high reactivity. The yield of activated cellulose is 98.87 wt.%.

The following are examples of the copolymerization of activated cellulose powder with acrylamide.

Example 8

A three-necked flask equipped with a stirrer, contact thermometer and reflux condenser is charged with 75 g (4.16 mol) of distilled water, 0.850 g (0.00524 mol) of cellulose powder with particle sizes of 10-100 μm and 1.0 g (0.800 wt. % of the monomers) emulsifier sodium alkylbenzenesulfonate and 12 g (0.169 mol) of acrylamide and include a stirrer. After the temperature of the mixture reaches 65 ° C, 0.5 g (0.4 wt% of the monomers) of the ammonium persulfate initiator of the radical polymerization is fed to the reactor. The copolymerization is carried out at a temperature of 70 ° C, and the reaction time is 80 minutes

The molar ratio of water: cellulose: acrylamide is 4.16: 0.00524: 0.168.

Example 9

Example 8 is carried out, except that 91 g (5.06 mol) of distilled water, 12.5 g (0.170 mol) of acrylamide, 0.800 g (0.00493 mol) of cellulose with a particle size of 200 μm are used.

The molar ratio of water: cellulose: acrylamide is 5.06: 0.00493: 0.170.

- 2 019859

Example 10

Carried out as in example 8, except that using 95 g (5.27 mol) of distilled water, 0.860 g (0.00524 mol) of cellulose powder with a particle size of 320 μm.

The molar ratio of water: cellulose: acrylamide is 5.27: 0.00524: 0.169.

The resulting copolymer based on cellulose powder and acrylamide in an aqueous medium has a pH of 7.37.5, the content of the copolymer is 12.5-14.6%, the viscosity of a 1% solution of the copolymer is 4.54-2.55 mm ² / s, the drying time of the film 4.5 hours, coating adhesion 1 point.

The resulting copolymer can be used as glue, thickener and raw materials for the paint industry.

Literature

1. Patent 20684419, Russia, IPC С08В 15/02, dated October 27, 1999.

2. Abstract. dis. for a job. Uch. Step. Cand. Chem. sciences. Frolova SV. (Institute of Chemistry of Komi, Scientific Center, Ur ORAN, 167610, Komi Republic. Syktyvkar, 48 Pervomaiskaya St.) Archang. Gos. tech. University, Arkhangelsk, 2008, 20 pp., ill. Bible 18. Rus.

3. Patent 015856 EVPO, С08В 1/00, dated December 30, 2011.

Table 1

No. Name of reagents Numbers of experiments and their results one 2 3 4 5 6 7 Taken one Distilled water, gr 297 291 285 276 291 276 291 2 Sodium pyrophosphate, gr 3 nine fifteen 24 nine 24 nine 3 Pulp amount, column 3 3 3 3 3 3 3 4 Pulp processing time, MIN 60 60 60 60 thirty twenty 60 5 Drying at a temperature of 100-105 ^and C, MIN 60 60 60 60 60 60 60 6 Grinding time min 8 8 8 8 8 8 4 RECEIVED 7 Cellulose powder gr 2.75 2.77 2.85 2.78 2.66 2.72 2.70 8 The fractional composition of the powder, weight. % 630 μm 8.52 2.02 1.13 2.10 6.99 10.96 15.60 320 μm 39.23 24.82 24.53 35.76 38,20 30.14 31.65 200 microns 34.62 27.95 29.05 29.20 32.65 24.65 25.85 100 μm 15.40 40.15 39.63 28.96 18.48 28.75 21.92 10 microns 2.23 5.06 5.66 !, 98 3.68 5.50 4.98 nine pH-aqueous dispersion of the powder, NUMBER 9.2 9,4 9.5 9.2 9.7 9.9 9.5 10 Activated cellulose yield % 91.48 97.98 98.87 97.90 93.02 89.04 84.40

table 2

No. Name of reagents Numbers of experiments and their results 8 nine 10 Taken one Distilled water, column 75 91 95 2 Cellulose Powder: 10-100 microns gr 0.850 - 200 microns gr - 0,800 - 320 μm gr - - 0.860 3 Sodium alkylbenzenesulfonate, N> ι, ο 1,0 1,0 4 Acrylamide gr 12.0 12.5 12.0 5 (ΝΗ ^ δζΟβ gr 0.5 0.5 0.5 6 Temperature, FROM 70 70 70 7 Reaction time, min 60 65 65 RECEIVED 8 An aqueous solution of a copolymer, gr 88.9 105.70 102.40 nine The dry residue of the copolymer, % 14.60 13.0 12.5 10 The viscosity of a 1% copolymer solution, mm7sec 6.52 4,54 12.55 eleven copolymer pH one 7.4 7.3 7.5 12 Film drying time, hour 4.2 4,5 4,5 thirteen Adhesion coating ball one one 14 Monomer Conversion, % 98.7 99.0 98.95

CLAIM

Claims (1)

CLAIM A method of activating cellulose, comprising treating cellulose with an aqueous solution of an activating agent, characterized in that it is treated with 1.0-8.0% aqueous sodium pyrophosphate solution for 20-60 minutes at a molar ratio of water: sodium pyrophosphate to give maximum fragility to the macromolecular structure of cellulose : cellulose 15.3-16.5: 0.01120.0902: 0.0185, dried at a temperature of 100-105 ° C for 60 minutes, followed by grinding to a particle size of 10-320 microns for 4-8 minutes to obtain maximum yield of activated cellulose 98.87 weight. % Eurasian Patent Organization, EAPO Russia, 109012, Moscow, Maly Cherkassky per., 2