RU2332438C1 - Method of spruce bark processing - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to chemical processing of wood and can be used at wood-processing enterprises and in wood-pulp and paper industry for spruce bark processing with obtaining coniferous wax, antocyanidin pigment, pectine and active coal. The method of spruce bark processing is described. It includes bark extraction with nonpolar solvent with extraction of coniferous wax, further isolating from bark of antocyanidin pigment and processing of remaining part of bark into active coal; after obtaining antocyanidin pigment the remaining part of bark is subjected to extraction with 0.5% water solution of ammonium oxalate at temperature 95-100°C with isolating pectine.

EFFECT: achieving practically full utilisation of bark with production of coniferous wax, antocyanidin pigment, pectine and active coal.

1 dwg, 2 tbl, 4 ex

Description

The invention relates to chemical processing of wood and can be used at woodworking enterprises and in the pulp and paper industry for processing bark of spruce to produce pine wax, anthocyanidin dye, pectin and activated carbon.

From literature it is known to use the bark of spruce to obtain a tannin extract (RU 2220206, publ. 12/27/2003), as well as essential oil (RU 2223776, publ. 02.20.2004).

A disadvantage of the known methods is the low assortment of products obtained from spruce bark.

A known method of processing larch bark, in which a non-polar solvent (hexane) is extracted with pine wax, and pectins are isolated. An equimolar mixture of oxalic acid and ammonium oxalate is used as an extractant, and acetone or ethyl alcohol are used as a precipitant. As a result, pectin is obtained from larch bark in an amount of 2-6% by weight of dry bark (V.A. Babkin, N. V. Ivanova, L. A. Ostroukhova and others. Extraction processing of larch bark into practical useful products // Coniferous boreal zone. 2003. Issue 1, S.113-116).

The disadvantage of this method is the low yield of pectin substances.

A known method of producing pectin from the bark of coniferous trees using extraction with a 1% solution of ammonium oxalate (SU 563154, 06/30/1977).

The disadvantage of this method is the low quality of the selected pectin. In this method, the core is washed three times with water to remove the accompanying impurities. However, a significant part of phenolic substances is not extracted from the bark with water and, upon subsequent acid hydrolysis, enters the target product (pectin). Products isolated from bark by water are not salable and, judging by the description, are waste products. Consequently, the low assortment of products obtained from the bark of coniferous trees should also be regarded as disadvantages.

The closest in technical essence and the achieved result is a method of processing larch bark into coniferous wax, anthocyanidin dye and activated carbon. The method consists in extraction of the bark with a non-polar solvent (for example, hexane) with the extraction of coniferous wax, followed by isolation of the anthocyanidin dye from the bark by treatment with ethyl alcohol containing 2-5% hydrochloric acid. The solid residue of the crust under conditions of oxidative carbonization is converted into activated carbons (RU 2175668, publ. 10.11.2001).

The disadvantage of this method is that the remainder of the larch bark after receiving the anthocyanidin dye is processed into activated carbons, that is, such a valuable class of extractive substances as pectins is not extracted.

The objective of the invention is to expand the range of products obtained from the bark of spruce and to achieve its almost complete utilization with the production of pine wax, anthocyanidin dye, pectin and activated carbon,

The problem is achieved in that in a method for processing bark of spruce, including extraction of the bark with a non-polar solvent with extraction of coniferous wax, subsequent isolation of the anthocyanidin dye from the bark and processing the remainder of the bark into activated carbon, according to the invention, after receiving the anthocyanidin dye, the bark residue is subjected to extraction with 0.5% aqueous solution of ammonium oxalate at a temperature of 95-100 ° C with the release of pectin.

A comparative analysis of the proposed method and prototype shows that the common features are:

- extraction of coniferous bark with a non-polar solvent;

- Isolation from the tarred bark of anthocyanidin dye;

- processing of bark into activated carbon.

Distinctive features of the proposed method from the prototype is:

- the selection of pectin from the remainder of the bark of spruce after receiving anthocyanidin dye by extraction with 0.5% aqueous solution of ammonium oxalate.

The invention is illustrated in the drawing, which shows a diagram of a process for waste-free processing of bark of spruce.

The method is as follows.

Spruce bark is crushed to particles 1-3 mm in size and subjected to extraction at the boiling point with a non-polar solvent (pentane, hexane, petroleum ether or BR-1 gasoline) in a Soxhlet apparatus for separating coniferous wax. The yield and degree of extraction of coniferous wax during the extraction of spruce bark with various non-polar solvents is shown in table 1.

Table 1
The yield and degree of extraction of coniferous wax during extraction of bark of spruce with non-polar solvents No. p / p Solvents The duration of the extraction, h Wax yield% of a.s. bark * Wax Recovery Rate one. Pentane 6 6.91 94.7 2. Hexane 6 7.00 95.9 3. Petroleum ether (40-70 ° C) 6 6.95 95.3 four. BR-1 gasoline 6 7.10 97.3 * - the yield of coniferous wax is given in% of the weight of absolutely dry bark of spruce

As can be seen from table 1, the maximum yield (7.1%) and the degree of extraction (97.3%) of coniferous wax are achieved by extraction of spruce bark with hexane and BR-1 gasoline.

The components of coniferous wax have a wide range of biological activity, on their basis a lot of medicines and cosmetics have been patented. Coniferous wax also has biocidal and hydrophobic properties and is used to create protective coatings that are resistant to moisture, bacteria and fungi.

The remainder of the bark is treated with 3-7% hydrochloric acid at a temperature of 70-82 ° C for 3-4 hours in ethanol and anthocyanidin dye is obtained. When the concentration of hydrochloric acid is less than 3%, the duration of the process of obtaining anthocyanidin dye sharply increases, and an increase in the concentration of hydrochloric acid of more than 7% is impractical, since side processes, for example, hydrolysis of fiber and dye destruction, are intensified. At a temperature below 70 ° C, it is impractical to obtain a dye, since the duration of the process increases (78 ° C - the boiling point of ethyl alcohol, 82 ° C - the boiling point of isopropyl alcohol). The use of alcohols with a boiling point above 82 ° C is impractical because the resulting dye is destroyed and its yield drops.

The uniqueness of anthocyanidin dyes lies in the fact that, depending on the number of substituents (OH groups) in the phenolic ring and the pH of the medium, they give plants, flowers, fruits, etc. various bright colors from yellow to purple and blue. Anthocyanidin compounds have a wide spectrum of biological activity, as well as food coloring and are widely used in the food industry. Currently, they are obtained from fruits, berries and vegetables (S. S. Tanchev. Anthocyanins in fruits and vegetables. M.: Food industry. 1980. 297 p.).

After receiving the anthocyanidin dye, the remainder of the spruce bark is subjected to extraction with a 0.5% aqueous solution of ammonium oxalate with the release of pectin.

Pectins have anti-inflammatory, enveloping properties, exhibit a detoxifying effect, adsorbing toxins of microorganisms, heavy metal ions, including radionuclides, glycosides, alkaloids, phenol and other harmful substances. Pectins can be used in veterinary medicine for the prevention and treatment of gastrointestinal diseases of farm animals.

The remainder of the crust remaining after the isolation of pectin is subjected to oxidative carbonization in a fixed or fluidized bed reactor at a temperature of 600-800 ° C. The output of activated carbon is 12-14%.

Characteristics of activated carbon obtained by oxidative carbonization from the bark of spruce after obtaining coniferous wax, anthocyanidin dye and pectin are presented in table 2.

table 2
Characteristics of activated carbon obtained by oxidative pyrolysis from spruce bark after receiving pectin AC characteristics Ash content,% 12-3 Bulk density 0.11-0.12 Iodine activity,% 79-83 The pore volume in water, cm ³ / g 2.15-2.27 MG activity, mg / l 139.8-144.6

The method of processing bark of spruce is confirmed by a specific example.

Example. Soxhlet's apparatus is charged with 100 g of spruce bark, crushed to a fraction of 1-3 mm, with a moisture content of up to 5%, which contains 7.1% resinous substances (coniferous wax), and is extracted with hexane at a boiling point (68.7 ° C) for 6 hours. After distillation of hexane, 6.4 g of coniferous wax are obtained, the recovery ratio is 95.9%.

To obtain an anthocyanidin dye, 0.5 g of a solid residue of spruce bark is charged into a 0.5 L round-bottom flask, after extraction with hexane, 250 ml of ethyl alcohol containing 4% hydrochloric acid are poured into the bark, closed with reflux condenser and boiled at 78 ° C for 3 ,5 o'clock. The solution in the flask acquires a dark cherry color. The reaction mass, without cooling, is filtered off from the bark, which is washed twice with 50-60 ml of hot ethyl alcohol on the filter. Then, the resulting dye solution was concentrated in vacuo, distilling off all ethyl alcohol, and diluted with 80-100 ml of water. The resulting anthocyanidin dye was filtered off and dried at room temperature. Yield 14%.

Pectin substances are extracted by extraction with a 0.5% aqueous solution of ammonium oxalate from the solid residue of the bark of spruce remaining after extraction of the anthocyanidin dye. The extraction is carried out at a temperature of 100 ° C and a hydraulic module of 1:30. The solution is separated from the remainder of the cortex by filtration on a suction filter. Then, the extract is clarified with activated carbon, a concentrated clarified solution under vacuum at a temperature of 55-60 ° C, and pectins are precipitated with ethyl alcohol. The precipitated pectins are separated on a suction filter, washed with alcohol and the finished product is dried. The yield of pectin is 12%.

The remainder of the crust after separation of pectin, oxidative carbonization is converted into activated carbon in a reactor with a fixed or fluidized bed at a temperature of 600-800 ° C. The output of activated carbon is 11-13%.

Thus, the proposed method allows to expand the range obtained from the bark of spruce products, as well as to achieve almost complete utilization of the bark of spruce. When processing 1 ton of bark of spruce according to the proposed method receive:

1. Coniferous wax up to 60-70 kg;

2. Anthocyanidin dye 130-140 kg;

3. Pectin 100-120 kg;

3. Active carbon 110-130 kg.

Claims (1)

A method of processing bark of spruce, including extraction of the bark with a non-polar solvent to extract softwood wax, subsequent isolation of the anthocyanidin dye from the bark and processing of the remainder of the bark into activated carbon, characterized in that after receiving the anthocyanidin dye, the bark residue is subjected to extraction with a 0.5% aqueous oxalic solution -ammonium acid at a temperature of 95-100 ° C with the release of pectin.