EA024328B1 - Process for producing cellulose powder - Google Patents

Abstract

The invention discloses a process for producing cellulose powder in chemical, pharmaceutical, food and other branches of industry. The essence of the invention: the process for producing cellulose powder by soaking crushed cellulose with an aqueous sodium sulphate solution for 20-50 min with molar ratio water:sodium sulphate:cellulose equal to 10.77-15.83:0.0422-0.1479:0.0154-0.02160 respectively, drying at a temperature of 100-105°C within 60 min with further milling to particle size of 10-320 μm, time of milling is 2-6 min, which results in obtaining flowing cellulose powder with content of particles with size of lower than 320 μm 99.53 wt.%.

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 condensation reaction is known in a cellulose solvent system. In order to accelerate and better dissolve the cellulose in the dimethylacetamide (DMAA) / YC1 system, cellulose activation is carried out, which consists in heating or boiling the cellulose solvent system, during which cellulose destruction occurs. Cellulose degradation in DMAA or DMAA / L1C1 proceeds according to 2 independent chemical processes, one of which is associated with slow cleavage of the end groups and the formation of furan structures, and the second 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. (one)

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

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 alcohol, polyacrylates, especially in the form of sodium salt) are added to the pulp. After extraction of hemicellulose, the resulting voids between the fibers are filled with expanders. The content of expanders in the processing of pulp ranges from 0.5 to 2.0% (m / m) calculated on cellulose.

The resulting treated pulp has a high reactivity. (2)

The disadvantages of the method are: the multi-stage process of activation of cellulose, the use of additional hydrophilic polymers and the production 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 , SDM, 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 is 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. (3)

Prototype.

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

The objective of the invention are: expanding the range of chemicals used in the crystallization-activation of cellulose, simplifying the technology of activation of cellulose and reducing wastewater.

The problem is solved by processing (cellulose grade MS-1A waste paper) cellulose with an aqueous solution of sodium sulfate for 20-50 minutes at a molar ratio of water: sodium sulfate: cellulose equal to 10.77-15.83: 0.0422-0 , 1479: 0.0154-0.0216, respectively, by filtration and drying at a temperature of 100-105 ° C for a period of 60 minutes, followed by grinding to particle sizes of 10-320 μm, grinding time 2-6 minutes, the yield of loose cellulose powder is 99.53 wt.%.

The pulp is impregnated with 3.0-7.0 wt.% Aqueous sodium sulfate with a pH of 9.4-9.7 units. And the impregnation time varies from 20 to 50 minutes, an increase in the concentration of sodium sulfate in the solution above 5% negatively affects the process of cellulose activation. The optimal conditions for the process of activation of cellulose are: a treatment time of 30-40 minutes, a grinding time of 6 minutes and a concentration of an aqueous solution of sodium sulfate of 5.0 wt.%, The yield of activated cellulose is 99.53 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 the cellulose, it is treated with an aqueous solution of sodium sulfate before grinding, followed by drying, and during grinding, the macromolecular and fibrous structure is destroyed to obtain a loose cellulose powder with high reactivity. [According to the prototype, cellulose activation is carried out with Lewis acids A1C1 ₃ and T1C1 ₄ in the presence of solvents CC1 ₄ , C ₆ H ₁₄ , C ₂ H ₅ OH to produce wastewater]. The advantage of the proposed method for the activation of cellulose compared with the prototype is the use of sodium sulfate as a crystallizing agent, expanding the range of chemicals for crystallization of cellulose, the availability of sodium sulfate, and the proposed process is environmentally friendly.

The method is as follows: prepare 3.0g7.0 wt.% An aqueous solution of sodium sulfate, then crushed cellulose is treated with an aqueous solution of sodium sulfate. The impregnated cellulose is separated from the sodium sulfate solution and dried, the dried cellulose is dried.

- 1,024328 becomes brittle and, when milled, the macromolecular and fibrous structures are destroyed to give loose cellulose powder with high reactivity. Based on activated cellulose and acrylamide, the copolymerization process proceeds under mild conditions at low temperatures.

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

Example 1. In a liter beaker equipped with a stirrer, load 194 g (10.77 mol) of distilled water, 16 g (0.0422 mol) of sodium sulfate, turn on the stirrer at a speed of 60 rpm and add 2 to the resulting aqueous solution of sodium sulfate 5 g (0.0154 mol) of pulp milled. Cellulose treatment is continued for 50 minutes, and then, at a temperature of 100-105 ° C., filtration and drying are carried out for 60 minutes and grinding is carried out for 6 minutes. The resulting loose cellulose powder is fractionated using sieves.

The molar ratio of water: sodium sulfate: cellulose is 10.77: 0.0422: 0.0154, respectively.

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

The quality of sodium sulfate is determined by GOST 6318-77, cellulose composition GOST 5982-82, waste paper GOST 10700-97, fractional composition of activated cellulose powder GOST 3584-73, viscosity of an aqueous solution of a copolymer GOST 1028-81, the degree of drying of the film of copolymers GOST 19007- 73, coating adhesion GOST 15140-78, the dry residue of the copolymers is determined by the physicochemical method, the hydrogen number of the solutions is determined by a pH meter, sodium lauryl sulfate TU 6-09-270-84, acrylamide GOST 3758-65, potassium persulfate GOST 4146-74.

Example 2. Carried out as in example 1, except that use 285 g (15,83 mol) of distilled water, 15 g (0,1056 mol) of sodium sulfate and the processing time of the pulp is 40 minutes

The molar ratio of water: sodium sulfate: cellulose is 15.83: 0.1056: 0.0154, respectively.

Example 3. Carried out as in example 2, except that the processing time of the pulp is 35 minutes

The molar ratio of water: sodium sulfate: cellulose is 15.83: 0.1056: 0.0154, respectively.

Example 4. Carried out as in example 2, except that using 279 g (15.5 mol) of distilled water, 21 g (0.1479 mol) of sodium sulfate and the processing time of cellulose is 30 minutes

The molar ratio of water: sodium sulfate: cellulose is 15.83: 0.1479: 0.0154, respectively.

Example 5. Carried out as in example 2, except that they use 3.5 g (0,02160 mol) of cellulose and the grinding time is 4 minutes

The molar ratio of water: sodium sulfate: cellulose is 15.83: 0.1056: 0.02160, respectively.

Example 6. Carried out as in example 2, except that the processing time of the pulp is 20 minutes and the grinding time is 4 minutes.

The molar ratio of water: sodium sulfate: cellulose is 15.83: 0.1056: 0.0154, respectively.

Example 7. Carried out as in example 3, except that the processing time of the pulp is 30 minutes and the grinding time is 2 minutes.

The molar ratio of water: sodium sulfate: cellulose is 15.83: 0.105: 0.0154, respectively.

The experiments show that when the cellulose is treated with an aqueous solution of sodium sulfate, followed by filtration and drying at a temperature of 100-105 ° C, it 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 acrylamide in the presence of a radical polymerization initiator.

Example 8. In a three-necked flask equipped with a stirrer, contact thermometer and reflux condenser, charge 70 g (3.88 mol) of distilled water, 1 g (0.00617 mol) of cellulose powder with a particle size of 10-320 μm emulsifier, 0.70 g (6.36 wt.% of the monomer) of sodium lauryl sulfate and 10 g (0.1408 mol) of acrylamide and include a stirrer. After reaching a temperature of 80 ° C., 0.4 g (3.63 wt.%) Of potassium persulfate radical polymerization initiator is fed to the reactor. The copolymerization is carried out at a temperature of 85 ° C and a reaction time of 90 minutes

The molar ratio of water: cellulose: acrylamide and wt.% Emulsifier sodium lauryl sulfate: initiator of potassium persulfate is 3.88: 0.00617: 0.1408: 6.36: 3.63, respectively.

Example 9. Carried out as in example 8, except that using 1.1 g (0.00740 mol) of cellulose powder with a particle size of 10-100 μm and 12 g (0.1690 mol) of acrylamide.

- 2 024328

The molar ratio of water: cellulose: acrylamide and wt.% Emulsifier of sodium lauryl sulfate: initiator of potassium persulfate is 4.16: 0.00740: 0.1690: 5.3: 3.03, respectively.

Example 10. Carried out in example 8, except that they use 1.4 g (0.00864 mol) of cellulose powder with a particle size of 10-1200 μm and 14 g (0.1971 mol) of acrylamide.

The molar ratio of water: cellulose: acrylamide and wt.% Emulsifier of sodium lauryl sulfate: initiator of potassium persulfate is 4.16: 0.00864: 0.1971: 4.5: 2.59, respectively.

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

The experiments show that when copolymerizing activated cellulose with a particle size of 10-320 μm with acrylamide, the process proceeds under mild conditions at a temperature of 85 ° C and a reaction time of 90 minutes, the dry matter content of the resulting copolymer is 16.0-16.8 weight .%, the viscosity of a 1% aqueous solution of the copolymer of 6.3-6.85 mm ² / s, the conversion of monomers is 98.20 wt.%. The resulting copolymer has high adhesion and can be used as glue and raw material for the production of emulsion paints.

Literature.

1. Nubgo1uys pgosezzes apb eopbeziop geasyopz ίη Pt e11i1ose zokep! 5y51esh K, K'-01she1yu1ase1ash10e 1shsh sYopbe. P1.2 OedgabaNop OG se11i1ose. Ро1утег., 2003, 44, No. 1, p. 7-47 English

2. Pat. No. 2434020 Russia, IPC С 08 В 1/08, 9/00, Д 21 С 9/00, publ. November 20, 2012

3. Abstract. dis. for a job. student step. Cand. chemical science. Frolova S.V. (Institute of Chemistry of Komi, scientific center of Ur ORAN, 167610 Komi Republic. Syktyvkar, 48 Pervomaiskaya St.) Archang. Gos. tech. University, Arkhangelsk, 2008.20 s, ill. Bible 18. Rus.

Table 1

No. Name of reagents Numbers of experiments and their results one 2 3 4 5 6 7 Taken one Distilled water g 194 285 285 279 285 285 285 2 Sodium Sulfate g 6.0 fifteen fifteen 21 fifteen fifteen fifteen 3 Cellulose ^g 2.5 2.5 2.5 2.5 3.5 2.5 2.5 4 Min processing time fifty 40 35 thirty thirty twenty thirty 5 Drying of treated waste paper, with 100-405 ° C min 60 60 60 60 60 60 60 6 Grinding time min 6 6 6 6 4 4 2 RECEIVED 7 G cellulose powder 1.98 2.22 2.14 2.07 2.24 2.45 2.40 8 Fractional composition of the powder% 0.630 μm 1.51 0.47 0.90 0.48 1.34 9.20 6.25 0.320 μm 42.93 35.03 38.29 47.34 47.32 40.25 43.77 0.200 μm 26.77 30.40 03/27 26.57 24.55 24.31 22.95 0.100 μm 23.74 24.76 22.52 19.32 09/20 22.72 16.67 0.10 μm 5.05 9.34 1.26 6.29 6.7 3.52 10.36 nine pH aqueous dispersions of powder units 9.0 9.2 9.6 9.0 9.2 9.5 9.2 10 The yield of cellulose powder% 98.49 99.53 99.10 98.52 98.66 69.39 93.75

table 2

Λί Name of reagents Numbers of experiments and their results 3 nine 10 Taken one Distilled water G 70 75 75 2 Cellulose powder, 10-320 microns g one 1.1 1.4 3 Sodium lauryl sulfate g 0.70 0.70 0.7 4 Acrylamide g 10 12 14 5 KZZtO, G 0.4 0.4 0.4 6 Temperature from 85 85 85 7 Reaction time min 90 90 90 RECEIVED 8 Copolymer aqueous solution g 802 87.32 89.85 nine Dry matter content % sixteen 16.2 16.8 10 solution pH units AND Viscosity of 1% copolymer aqueous solution mm + s 6.85 6.65 6.30 12 Film drying time hour 5 4.5 5 thirteen Film adhesion ball one one one 14 Monomer Conversion % 96.82 97.8 98.2

CLAIM

Claims (1)

CLAIM A method of obtaining cellulose powder, comprising treating pulverized cellulose for 20-50 minutes with a 3.0-7.0% aqueous solution of sodium sulfate with a hydrogen number of 9.4-9.7 units. at a molar ratio of reagents water: sodium sulfate: cellulose, equal to 10.7-15.83: 0.04220.01479: 0.0154-0.0216, respectively, filtering and drying at a temperature of 100-105 ° C for 60 minutes, followed by grinding for 2-6 minutes