RU2335532C1 - Method of cedar bark integrated processing - Google Patents

Abstract

FIELD: technological processes; chemistry.

SUBSTANCE: method of cedar bark integrated processing is described, which includes extraction of bark with nonpolar dissolvent with extraction of coniferous wax, further extraction of anthocyanidin colouring agent from bark and processing of bark remains into active coal, at that after preparation of anthocyanidin colouring agent bark remains are subjected to extraction with 0.4-1.0% aqueous solution of ammonium oxalate at the temperature of 95-100°C with extraction of pectin.

EFFECT: suggested method provides achievement of practically complete utilisation of cedar bark with preparation of coniferous wax; anthocyanidin colouring agent; pectin and active coal and makes it possible to increase pectin output and its quality.

1 dwg, 3 tbl, 6 ex

Description

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

It is known to use cedar bark to obtain a biologically active compound of resveratrol (RU 2294919, publ. 10.03.2007) and essential oil (RU 2223776, publ. 02.20.2004).

A disadvantage of the known methods is the low range of products obtained from cedar 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% of the dry bark weight (V.A. Babkin, N. V. Ivanova, L. A. Ostroukhova and others. Extraction processing of larch bark into practically useful products. // Coniferous boreal zones. 2003. Issue 1, p.113-116).

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

The closest in technical essence and the achieved result is a method of processing the bark of Siberian larch into coniferous wax, anthocyanidin dye and activated carbon, which consists in extracting the bark with a non-polar solvent (e.g. hexane) at a boiling point of the solvent, distilling off the solvent, treating the solid residue of the bark with hydrochloric acid concentration 3-7% at 78-82 ° C in ethyl or isopropyl alcohol. After receiving the dye, the remainder of the crust under conditions of oxidative carbonization is converted into activated carbon (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 cedar bark and achieve almost complete utilization of cedar bark with the production of pine wax, anthocyanidin dye, pectin and activated carbon.

The problem is achieved in that in a method for complex processing of cedar bark, including extraction of coniferous bark with a non-polar solvent to produce coniferous wax, processing the remainder of the bark into anthocyanidin dye and activated carbon, according to the invention, the residue of cedar bark after extraction of anthocyanidin dye is extracted with 0.4- 1.0% 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:

- raw materials - bark of coniferous trees

- extraction of the bark with a non-polar solvent with the extraction of coniferous wax

- subsequent isolation from the cortex of anthocyanidin dye

- processing of bark into activated carbon.

A distinctive feature of the proposed method from the prototype is that the cedar bark is processed (larch bark is used in the prototype). In addition, unlike the prototype, the remainder of the cedar bark after receiving anthocyanidin dye is extracted with 0.4-1.0% solution of ammonium oxalate with the release of pectin.

It was unexpectedly discovered that after the preparation of the anthocyanidin dye from the cedar bark, it is possible to isolate more pure pectin than from the bark sequentially extracted with hexane, ethanol and water. This is due to the removal of phenolic substances from the cortex upon receipt of the dye.

The invention is illustrated by the drawing, which shows a diagram of the process of waste-free processing of cedar bark.

The method is as follows.

Cedar bark is crushed to particles with a size of 1-3 mm and subjected to extraction at the boiling point with a non-polar solvent (pentane, hexane, petroleum ether or BR-1 gasoline) in a Soxhlet type apparatus for separating coniferous wax. The yield and degree of extraction of coniferous wax during the extraction of cedar 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 cedar bark 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 4.47 95.1 2. Hexane 6 4,58 97.5 3. Petroleum ether (40-70 ° C) 6 4.43 94.3 four. BR-1 gasoline 6 4.60 97.8 * - the yield of coniferous wax is given in% of the weight of absolutely dry bark

As can be seen from table 1, the maximum yield (4.6%) and the degree of extraction (97.8%) of coniferous wax are achieved by extraction of cedar 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.

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 an anthocyanidin dye, the remainder of the cortex is subjected to extraction with 0.4-1.0% aqueous solution of ammonium oxalate to obtain pectin. When the concentration of an aqueous solution of oxalic ammonium is less than 0.4% and more than 1.0%, the yield of pectin is reduced.

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 pyrolysis from cedar bark after receiving anthocyanidin dye and pectin are presented in table 2.

table 2 Characteristics of activated carbon obtained by oxidative pyrolysis from cedar bark after receiving pectin AC characteristics Ash content,% 14-15 Bulk density 0.11-0.12 Iodine activity,% 77-81 The pore volume in water, cm ³ / g 2.2-2.3 MG activity, mg / l 142.7-148.5

A method of processing cedar bark is confirmed by a specific example.

Example 1. In a Soxhlet apparatus, 100 g of cedar bark, crushed to a fraction of 1-3 mm, are loaded, with a moisture content of up to 5%, which contains 4.7% resinous substances (coniferous wax), and extracted with hexane at a boiling point (68.7 ° C) within 6 hours. After distillation of hexane, 4.6 g of coniferous wax are obtained, the recovery ratio is 97.5%.

To obtain an anthocyanidin dye, 0.5 g of cedar 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 a temperature of 78 ° C for 3.5 hours. 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 bark remaining after the extraction of the anthocyanidin dye. The extraction is carried out at a hydraulic unit of 1:30 in a water bath (temperature 95-100 ° C). The solution is separated from the remainder of the cortex by filtration on a suction filter. Precipitation of pectins is carried out with ethyl alcohol or isopropyl alcohol. The precipitated pectins are separated on a suction filter, washed with alcohol and the finished product is dried. The yield of pectin is 9.8%.

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 700 ° C. The yield of activated carbon is 13%.

Example 2-6 The experiment is carried out analogously to example 1, but the extraction of pectin substances is carried out at the following concentrations of a solution of ammonium oxalate 0.5-1.0%. The results are presented in table 3.

Table 3 The dependence of the yield of pectin substances on the concentration of a solution of oxalic ammonium No. The concentration of a solution of oxalic ammonium,% The output of pectin,% one 0.4 8.1 2 0.5 9.8 3 0.6 9.9 four 0.7 10.1 5 0.8 10.6 6 0.9 10.7 7 1,0 10.6

Thus, the proposed method allows to expand the range of products obtained from cedar bark, as well as to achieve almost complete utilization of the bark.

When processing 1 ton of cedar bark according to the proposed method receive:

1. Coniferous wax up to 40-45 kg;

2. Anthocyanidin dye 130-140 kg;

3. Pectin 80-90 kg;

3. Active carbon 120-140 kg.

Claims (1)

A method for complex processing of cedar bark, including extraction of coniferous bark with a non-polar solvent to produce coniferous wax, processing of the remainder of the bark into an anthocyanidin dye and activated carbon, characterized in that the remainder of the bark after receiving the anthocyanidin dye is extracted with 0.4-1.0% aqueous a solution of oxalic ammonium at a temperature of 95-100 ° C with the release of pectin.