SU751808A1 - Method of preparing microcrystalline cellulose - Google Patents

Description

one

The invention relates to the chemistry of high-molecular compounds, more precisely to a method of hydrolysis of cellulose to the so-called "limit degree of polymerization with the production of microcrystalline cellulose (MCC).

MCC can be used in a wide variety of national economic entities.

As a filler and stabilizer in the preparation of pharmaceutical preparations and cosmetic and 10 creams, as food additives. In the ceramic industry to produce high quality porcelain, for the production of refractory materials. It can be widely used as a stabilizer for water-latex paints and as various purposes sorbents, etc.

A known method for producing microcrystalline cellulose 1 from various 20 cellulose raw materials of cotton, cotton linter of wood pulp, viscose silk, tire cord and others under optimal conditions: aqueous 2.5N. HC1 solution at 105 ° C for 15 minutes. Depending on the type of cellulosic raw material, the JV is within the limits of 150-250. The method requires the use of cellulose.

A known method of producing MCC 2 by processing wood pulp and cotton 30

go linter 1 n. After the hydrolysis, the residue (product yield 90% of taken cellulose) was washed with water until neutral, then with ethanol and dried in vacuo at 40 ° C.

JV, depending on the type of cellulosic raw material, was 165-275.

In the above process, expensive cellulose predisposed for chemical processing is also used as a raw material.

The aim of the invention was to reduce the cost of microcrystalline cellulose and expand the raw material base. This goal is achieved by using hydrolyzed lignin as a feedstock from the hydrolysis industry.

The technology for the production of microcrystalline cellulose from hydrolytic lignin consists in treating its aqueous suspension with nitric acid, the total concentration of which is 1-2 n.

The treatment is carried out at a temperature of 90-100 ° C, module 7-8 with stirring for 4-5 hours. During processing, the lignin is subjected to oxidative hydrolytic cleavage and goes into solution. The solid residue is separated from the solution and treated with alkali (concept. Aqueous

NaOH solution of 0.25-0.5%) at a modulus of 10-15 and a temperature of 80-100 ° C for 30-60 minutes.

For the more purified light sample obtained, the residue after treatment with nitric acid is suspended with stirring in acetone at room temperature and module 10-15 for 30-60 minutes, and then treated with 0.25-0.5% aqueous solution of NaOH at module 10-15 and a temperature of 80-100 ° C for 30-60 minutes.

The yield of MCC product is 15–25% of the amount of lignin taken. The degree of polymerization is 120-130.

The products of complete hydrolysis of the obtained MCC contains mainly (up to 97-99%) glucose.

According to X-ray diffraction and IR spectroscopy (Table 1), the MCC according to the claimed method corresponds to the MCC according to the method of the prototype.

The cellulosic residue is easily dispersed in an aqueous suspension (dry venous concentration 3%) by ultrasound and gives stable cream-like gels, which is characteristic of microcrystalline celluloses.

The combination of the above indicators suggests that the cellulosic residue obtained but not the proposed method is microcrystalline cellulose and can be used in the same areas as the MCC, obtained from pure cellulose according to the prototype method.

Example 1. 100 g of hydrolyzed lignin are suspended in 500 ml of water for 4 hours at room temperature, 200 ml of nitric acid are added (specific weight 1.35).

The mass temperature due to the exotherm of the oxidation reaction of lignin is set in the range of 90-100 ° C, and the final concentration of HNOs in full corresponds to -1 n solution. Then the mass is additionally boiled for 5 hours (module 7).

After cooling, the solid residue is separated by filtration (yield 50%).

The residue is then suspended in 500 ml of a 0.5% aqueous solution of NaOn (module 10), heated to 100 ° C and maintained at this temperature and displaced for 30 minutes. The residue, microcrystalline cellulose (MCC), is separated from the alkaline solution by filtration, washed with water and dried.

The output of the MCC 15% from the original lignin; SP 123. The content of hardly hydrolyzable polysaccharides (TPG) is 5.3%.

Example 2. 100 g of hydrolyzed lignin are suspended in 500 ml of water for 4 hours at room temperature, 300 ml of nitric acid (specific weight 1.35) are added.

The temperature of the mass is established in the range of 90-100 ° C, and the final concentration of HNOs fully corresponds to 2 n. solution. The mass is additionally boiled for 4 hours (module 8).

The residue is suspended in 750 ml (module 15) of a 0.25% aqueous solution of NaOH, heated to 80 ° C and maintained at this temperature and without stirring for 60 minutes. The residue is separated as in Example 1. The yield of MCC is 20%. SP 130. The TGP content is 5.8%.

Example 3. The oxidation of hydrolytic lignin is carried out as in Example 1.

The residue is separated by filtration, suspended in 500 ml (module 10) of acetone and kept at room temperature for 60 minutes. The residue is separated from the solvent and treated with 750 ml (module 15) of a 0.25% aqueous solution of NaOH, as in Example 2. The yield of MCC is 20%. SP 130. The TGP content is 4.8%.

Example 4. The oxidation of hydrolytic lignin is carried out as in Example 1.

The residue is suspended in 750 ml of acetone (module 15) and stirred at room temperature for 30 minutes. The residue is separated from the solvent and treated with 500 ml of a 0.5% aqueous solution of NaOH (module 10) as in Example 1. The yield of MCC is 15%, SP 120. The THP content is 4.2%.

The proposed method for the production of microcrystalline cellulose is simple to implement. No special equipment is required for its implementation. It makes it possible to use the waste of the hydrolytic industry (lignin), which is up to 3 per year, and to obtain valuable MCC cellulosic material, the amount of which can be

full use of waste up to 600 thousand tons / year. Thus, costly cellulosic raw materials are significantly saved; the cost of such a MCC will decrease.

Claims (2)

1. A method of producing microcrystalline cellulose by treating a cellulose-containing raw material with an acid when heated, characterized in that, in order to increase the production and expansion of the raw material base, an aqueous suspension of hydrolysis lignin is used as the cellulose-containing raw material, and 1-2 N as acid. an aqueous solution of nitric acid, the treatment is carried out for 4-5 hours at 90-100 ° C and a module 7-8, after which the undissolved residue is treated 0,25-0,5% aqueous solution of caustic soda 30-60 minutes at 80-100 ° C and module 10-15. 2. A method according to claim 1, characterized in that the insoluble residue is pre-extracted with acetone for 30 to 60 minutes at room temperature and module 10-15. Information sources, taken into account in the examination 1. O. Battista. "Ind. Eng. Chem. 1950, 42, 502. 2. N. E. Kotelnikova, E. A. Petropavlovsky, V. A. Shevelev, A. A. Volkova, G. G. Vasilyeva. The interaction of microcrystalline cellulose with water, 1976, 10, 391-399 (irotype).