EA024458B1 - Process for cellulose activation - Google Patents

Abstract

The use: a process for producing activated cellulose can be used in chemical, pharmaceutical, food and other branches of industry. The essence of the invention: cellulose is treated with an aqueous solution of sodium tetraborate, then it is filtered, dried at a temperature of 100-105°C within 60 min with further milling to particle size of 10-320 μm, which results in obtaining flowing cellulose powder with high reactivity, the yield is 98.02 wt.%. The proposed process for cellulose activation 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 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 obtained cellulose powder is 80-120, which is half the value of the specific 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 (1).

The disadvantage of this method is the activation of cellulose with chemicals in the presence of solvents to produce wastewater.

A known method of activation and copolymerization of cellulose as follows: crushed pulp is treated with an aqueous solution of potassium persulfate with a concentration of 2.0-4.1 wt.%, Then carry out drying at a temperature of 100-105 ° C for 60-90 minutes In this case, the brittleness of the macromolecular structure of cellulose is maximally increased, and when grinding within 8-44 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.% (2).

The disadvantages of the method of activation of cellulose are the long processing time and grinding and low yield of cellulose powder.

The invention relates to increasing the reactivity of pulp. The pulp contains up to 10% hemicellulose and, with 11 ± 3% alkaline treatment, hemicellulose is extracted between the fibers and voids are formed. During alkaline treatment, hydrophilic polymers, the so-called extenders (polyethylene glycols, polyvinyl alcohols, polyacrylates, especially in the form of sodium salt) are added to the pulp. After hemicellulose extraction, the resulting void between the fibers is filled with expanders. The content of expanders during alkaline treatment of pulp varies in the aisles from 0.5 to 2.0% (m / m) in the calculation of cellulose.

The resulting treated pulp has a high reactivity (3). Prototype.

The disadvantages of the method are the multi-stage activation process of cellulose, the use, in addition to alkali, of additional hydrophilic polymers and the production of wastewater.

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 treating MS-1A-cellulose brand waste paper with an aqueous solution of sodium tetraborate for 20-40 minutes at a molar ratio of water: sodium tetraborate: cellulose 22.22: 0.03976-0.0596: 0.0185-0, 02469, respectively, by filtration and drying at a temperature of 100-105 ° C for 60 minutes, followed by grinding for 3-6 minutes, the obtained loose cellulose powder with a particle content of 10, 100, 200 and 320 microns has a high reactivity.

The proposed method for the activation of cellulose in comparison with the prototype consists in using MS-1A waste paper as a raw material, to impart maximum fragility to the macromolecular structure of the cellulose, it is treated with an aqueous solution of sodium tetraborate and then dried, and the macromolecular and fibrous structure is destroyed when grinding to obtain a granular cellulose powder with high reactivity. The content of the main fraction with particle sizes from 10-320 μm is 98.02 wt.%. The proposed cellulose activation process is environmentally friendly. [According to the prototype, cellulose activation is carried out by alkaline treatment of the pulp in the presence of hydrophilic polymers, while hemicellulose is extracted from the fiber and the resulting voids are filled with hydrophilic polymers with the release of a large amount of wastewater].

The method is as follows. A 2.0-4.0% aqueous solution of sodium tetraborate is prepared, then the crushed cellulose is treated for 15-40 minutes, then filtered after drying at a temperature of 100-105 ° C for 60 minutes, and the macromolecular and fibrous structure of cellulose is destroyed by grinding. The resulting free-flowing cellulose powder is highly reactive.

For a better understanding of the invention, examples are given below.

Example 1

400 g (22.22 mol) of distilled water, 8 g (0.03976 mol) of sodium tetraborate are loaded into a liter beaker equipped with a stirrer, 3 g (0.0185 mol) of cellulose are added to the resulting aqueous solution and treated for 20 minutes, after they are dried at 105 ° C for 60 minutes with grinding for 6 minutes, and the obtained free-flowing powder is subjected to sieve analysis.

- 1,024,458

The results of the experiments are presented in table. one.

Sodium tetraborate is determined according to GOST 8429-77, waste paper - GOST 10700-97, cellulose - GOST 5982-82, fractional composition of activated cellulose powder according to GOST 3584-73, acrylamide - TU-6-09-4547-77, sodium lauryl sulfate according to TU -6-09-270-84, potassium persulfate according to GOST 4146-74, the viscosity of the copolymer aqueous solution according to GOST 1028-81, the degree of drying of the copolymer film according to GOST 19007-73, coating adhesion according to GOST 15140-78, the dry residue of the copolymers is determined by physicochemical method.

Example 2

The process is carried out as in example 1, except that 10 g (0.04970 mol) of sodium tetraborate are used.

The molar ratio of water: sodium tetraborate: cellulose is 22.22: 0.04970: 0.0185.

Example 3

The process is carried out as in example 1, except that 12 g (0.0596 mol) of sodium tetraborate are used.

The molar ratio of water: sodium tetraborate: cellulose is 22.22: 0.0596: 0.0185.

Example 4

The process is carried out as in example 1, except that use the processing time of cellulose 30 minutes

The molar ratio of water: sodium tetraborate: cellulose is 22.22: 0.03976: 0.0185.

Example 5

The process is carried out as in example 1, except that 4 g (0.0246 mol) of cellulose are used.

The molar ratio of water: sodium tetraborate: cellulose is 22.22: 0.03976: 0.0246.

Example 6

The process is carried out as in example 2, except that the pulp processing time is 20 minutes and the grinding time is 4 minutes.

The molar ratio of water: sodium tetraborate: cellulose is 22.22: 0.04970: 0.0185.

Example 7

The process is carried out as in example 1, except that the pulp processing time is 40 minutes and the grinding time is 3 minutes.

The molar ratio of water: sodium tetraborate: cellulose is 22.22: 0.03976: 0.0185.

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

Example 8

3.88 mol of distilled water, 1.5 g (0.00926 mol) of cellulose powder with a particle size of 100 μm, emulsifier 5.2 wt.% (From monomers) lauryl sulfate are charged into a 3-neck reactor equipped with a stirrer, contact thermometer and reflux condenser sodium and 10.0 g (0.1408 mol) acrylamide and include a stirrer. After reaching a temperature of 85 ° C, 2.6 wt.% Of potassium persulfate radical polymerization initiator is fed into the reactor. The copolymerization is carried out at a temperature of 75 ° C and a reaction time of 70 minutes

The molar ratio of water: cellulose: acrylamide is 3.8: 0.00926: 0.1408.

Example 9

Carried out according to example 8, except using 10 g (0.1408 mol) of acrylamide, 1.5 g (0.00926 mol) of cellulose powder with a particle size of 200 μm.

The molar ratio of water: cellulose: acrylamide is 3.05: 0.00926: 0.1408.

Example 10

Carried out in example 8, except using 0.00926 mol of cellulose powder with a particle size of 320 microns.

The molar ratio of water: cellulose: acrylamide is 3.33: 0.00926: 0.1408.

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

The experiments show that during copolymerization of activated cellulose with a particle size of 10-320 microns 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 13-7.0 wt.%, Viscosity 1% aqueous solution of a copolymer of 2.4-3.2 mm ² / s, the conversion of monomers is 98.02 wt.%.

The resulting copolymer has high adhesion and can be used as glue and raw material for the production of emulsion paints.

- 2 024458

Literature.

1. Abstract. dis. for a job. student step. Cand. Chem. Sciences Frolova S.V. (Institute of Chemistry of the Komi Scientific Center, Ur. ORAN, 167610 Komi Republic, Syktyvkar, 48 Pervomaiskaya St.) Arkhang. Gos. tech. CNT, Arkhangelsk, 2008, 20 pp., ill. Bible 18 Rus.

2. Eurasian patent 015856, IPC С08В 1/00, 2011.12.30.

3. Pat. No. 2434020 Russia, IPC С08В 1/08, 9/00, D21 С9 / 00, publ. November 20, 2011

Table 1

26 Name of reagents Numbers of experiments and their results one 2 3 4 5 6 7 one Taken Distilled water, g. 400 400 400 400 400 400 400 2 ΝΗιΒ, ^ Ογ, g. 8.0 10.0 12.0 8.0 8.0 10.0 8.0 3 Waste paper MS-1A g. 3.0 3.0 3.0 3.0 4.0 3.0 3.0 4 Time of processing, min twenty twenty 40 thirty thirty twenty 40 5 Drying at 100-105''С, min 90 90 90 90 90 90 90 6 Grinding time min 6 6 6 6 6 4 3 7 RECEIVED Powder obtained g. Fractional composition of cellulose powder, % 630 μm 7.9 2.98 1.98 2.22 2.97 3.25 9.30 8 320 μm 15.79 13.69 19.86 15,55 20.83 15.21 16.28 200 microns 23.68 35.71 33.12 31.11 32,74 36.50 23.25 100 μm 31.60 35.71 33.12 37.77 31.54 34.62 28.02 10 microns 21.03 11.91 11.92 13.35 11.92 10.42 23.25 nine pH aqueous dispersion powder one 7.2 7.4 7.5 7.0 7.2 7.5 7.0 10 Cellulose powder yield, 92.1 97.02 98.02 97.78 97.03 96.75 90.80

table 2

Name of reagents Numbers of experiments and their results 8 nine 10 one Taken Distilled water, g. 70 55 60 2 Sodium lauryl sulfate, g. 0.6 0.6 0.6 3 Cellulose powder, including g. 100 μm 1,5 - 200 microns 1,5 - 320 μm 1,5 4 Acrylamide g. 10.0 10.0 10.0 5 Initiator g. 0.3 0.3 0.3 6 Temperature, from 75 75 75 7 Reaction time, min 70 75 75 8 RECEIVED Copolymer aqueous solution, g. 82,4 67.4 72,4 nine Dry copolymer residues, % 13.0 17.0 16,0 10 The viscosity of a 1% copolymer aqueous solution, mm ‘/ s 2.7 3.2 2,4 10 pH one 7.2 7.3 7.2 eleven Film drying time, hour 3 3 3 12 Adhesion coating, ball one thirteen Monomer Conversion, % 97.82 98.21 98.92

CLAIM

Claims (1)

A method of activating cellulose to obtain a loose cellulose powder with a particle size of 10320 μm by treating the cellulose with an alkaline solution, characterized in that the cellulose-containing waste paper of the grade MS-1A is used as raw material, to give maximum fragility to the macromolecular structure of cellulose, it is treated with an aqueous solution of sodium tetraborate in for 20-40 min at a molar ratio of water: sodium tetraborate: cellulose equal to 22.22: 0.03976-0.0596: 0.0185-0.0216, then filtered, dried at a temperature of 100-105 ° C in echenie 60 min and produce milled for 3-6 minutes.