FI123346B - Method of treatment of birch bark and use of the product - Google Patents

Description

Method for treating birch bark and using the product

FIELD OF THE INVENTION

The present invention relates to a process for recovering birch bark extract, the method comprising the steps of subjecting birch bark to hydrolysis using a solvent-containing hydrolysis liquid, separating the insoluble portions of the bark from the remaining solvent liquid; providing a liquid phase comprising said solvent liquid, acidifying the liquid phase; precipitating the extracts from the liquid phase by increasing the relative amount of water in the liquid phase; recovering the extract. The invention further relates to the use of animal feed obtainable by this process, as well as the use of birch bark extract in food, animal feed, pulp, paper and board, dyes and paper coatings closures.

BACKGROUND OF THE INVENTION

Birch bark is a potential source of various organic chemicals, and birch bark chemicals have been shown to be effective in a variety of pharmaceutical and industrial applications. Birch exterior contains, for example, betulinol, suberin and phenolic groups; in general, birch bark consists of 30-60% suberin consisting of long chain fatty acids. Some of the fatty acids contain epoxy groups and other functionalities such as hydroxyl groups. The fatty acids may also be bound to phenolic groups. Various Betula species have been reported to be significant sources of suberin.

Various methods for isolating birch bark extracts are described in WO 2007/045728 A1 and US 4,732,708, wherein the oxidation step is carried out at 200-400 ° C with co 25 potassium permanganate or chromic acid, and WO 2007/121482 A1 where c3 pure betulinol and suberin fatty acids are isolated that the process involves purifying the io extract with water-insoluble solvents and crystallizing betulinol from this solvent fraction. US 7,264,184 discloses a sequential isolation process of pure suberic acids g, US 7,198,808 describes a process for the extraction of co 30 betulin and lupeol and WO 2008/027426 A1 relates to birch bark pelletization before extraction to produce pure betulinol.

WO 2010/093320 describes a method for separating a suberin monomer from a plant material containing suberin and / or cutin. Each of the methods described above describes the secretion and purification of certain birch bark constituents.

It should be noted that all documents mentioned herein ("the documents referred to") and any document or reference mentioned herein, as well as all literature, specifications, instructions, product information sheets, material information sheets 5 and the like, as well as methods are hereby incorporated herein by reference.

SUMMARY OF THE INVENTION

The present invention relates to a method for treating birch bark for the recovery of birch bark extract. The method comprises subjecting the birch bark to hydrolysis; separating the insoluble shell portions from the liquid phase; acidifying the liquid phase; precipitating extracts from the liquid phase by increasing the relative amount of water in the liquid phase; extracting and / or recovering the extract. The invention further relates to the use of animal feed obtainable by this process, as well as the use of birch bark extract in food, animal feed, pulp, paper and board, dyes, paper coatings, and the like.

An advantage of the present invention is that varying the water content after hydrolysis and acidification increases the yield and quality of the extract product and improves process stability. The increased amount of water is achieved by adding additional water after acidification and / or, for example, evaporating the solvent from the acidified hydrolysis fluid.

A further advantage of the invention is that the amount of water during the precipitation also contributes to the removal of salts formed during the acidification of the alkaline hydrolysis fluid. This solves the prior art problem of leaving a salt formed in the final product. The quality of the product is improved because washing removes o impurities from the extract.

A further advantage of the invention is that the birch bark extraction process is more stable if the hydrolysis is carried out at a controlled water content of the solvent.

In a preferred embodiment of the invention solves the problem of prolonged hydrolysis since it is not necessary for the hydrolysis solution to contain excess water. The birch bark extraction methods known in the art have been unstable due to problems with hydrolysis regulation. Particularly, if more water is present in the hydrolysis solution, 2 this will result in an excessively invasive hydrolysis in which the lignin structure of the suberin is also degraded.

This causes additional aromatic impurities in the final product, which makes it difficult to remove the hydrolysis fluid and the precipitate as the birch bark softens.

Another advantage of the bark extracts of the invention is that they are natural products that are suitable for sustainable use and environmentally friendly. They are generally of low toxicity and are well tolerated at levels that are effective in influencing, for example, the digestive tract microbiota of animals.

10 BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic illustration of a method of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides an improved process for providing a crude extract by hydrolysis and acidification in the presence of water.

In the present specification and claims, the following terms have the meanings given below.

As used in the specification and claims, the term "extract" refers to the product obtained by the process of the invention. Preferably, the extract comprises and / or contains suberin fatty acids, betulinol, phenolic complexes and / or a combination thereof. Optionally, the extract is concentrated to provide an extract rich in drying. Higher amount of water during precipitation typically results in higher amount of betulinol in extract o as well as lower amount of water and correspondingly higher level of fatty acids.

The term "hydrolysis fluid" refers to the fluid used in hydrolysis. Preferably, the liquid used for alkaline hydrolysis of, for example, processed birch bark comprises or consists of 1 to 5% by weight, preferably 10% to 30% by weight, more preferably 15 to 25% by weight of water of alkaline hydroxide, solvent and water. , most preferably about 20% by weight of the total amount of liquids.

3

The term "bark" refers to birch bark of various 2tetw / a species, including mainly the birch bark.

The term '' solvent 'refers to various solvents typically used in the present invention for hydrolysis and / or washing. These solvents include alcohols such as ethanol or isopropanol, acetone, cyclohexane, ethyl acetate, water or mixtures thereof.

As used in the specification and claims, the term "feed" or "animal feed" refers to all or part of the composition of an animal feed. Thus, unless otherwise stated, the term "feed" or "animal feed" should be understood to include complementary feed, premixes, water or other drinkable liquids, etc. The feed may comprise various active ingredients.

As used in the specification and claims, the term "animal" refers to all kinds of animals such as solipeds, ruminants and aquatic animals, including fish and crustaceans. These animals can be farm animals or pets. Examples of various animals, including their offspring, include cows, beef cattle, pigs, poultry, sheep, goats, horses, cats, dogs, shrimps, and sea crabs.

The present invention relates to a process for recovering a product extract from a birch bark, the process comprising the following steps or any desired combination thereof: a) Mechanical treatment of the birch bark, preferably by log stripping, cutting, crushing, grinding, tearing, milling or any combination thereof.

The inner and outer shells are usually separated, for example, by screening or water separation.

“25 In water separation, the outer shell usually floats and the inner shell gets wet and sinking, o

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b) Exposing the birch bark to hydrolysis using a hydrolysis fluid comprising a cp 4 solvent, preferably a basic hydrolysis using a hydrolysis fluid comprising C 1 alkali hydroxide, solvent and water so that the amount of water in the hydrolysis fluid

CC

is typically 5 to 50% by weight of the total amount of liquids, preferably 10 to 30% by weight, more preferably 15 to 25% by weight, most preferably about 20% by weight. Preferably, the solvent added in step b) is added at nearly boiling point.

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(c) Separation of the insoluble fractions of the shell from the residual solvent after hydrolysis. Typically, the insoluble shell portion is washed again with solvent 4 and / or evaporated to remove solvent. In a preferred embodiment of the invention, the solvent and / or vapor mixture is typically combined with the solvent liquid to form a liquid phase.

d) Acidification of the liquid phase, wherein the pH is adjusted from pH 4 to pH 2, more preferably pH 3 to pH 2, including pH 3.9, 3.8, 3 , 7, 3.6, 3.5, 3.4, 3.3, 3.2, 3.1, 2.9, 2.8, 2.7, 2.6, 2.5, 2.4 , 2.3, 2.2 or 2.1 to pH 2. In a preferred embodiment, hydrochloric acid is added for acidification.

e) Precipitation of the extracts from the liquid phase by increasing the relative amount of water in the liquid phase. The preferred amount of water in the precipitation step is between 30-70% by volume, more preferably 55-65% by volume, most preferably about 60% by volume of the total amount of liquids, including the preferred amount of water of 68, 63, 60, 58, 53, 50 , 48, 45, 43, 40, 38, 35, 33% by volume to 30% by volume. In preferred embodiments of the invention, the relative amount of water is increased by adding 15 additional water to the liquid phase and / or evaporating the solvent from the acidified liquid phase, typically by adding 30-70 vol%, more preferably 45-55 vol%, most preferably approximately the same volume of water.

(f) Extraction and / or recovery of the extract. Typically, the precipitated and washed extract from step e) is filtered and optionally concentrated by evaporation, preferably at a temperature of 70 to 90 ° C, more preferably 70 to 80 ° C, before drying. In preferred embodiments of the invention, the drying is carried out in a batch vacuum dryer, for example a horizontal Lödige Druvatherm device, a spray dryer or a thin film evaporator. Typically, the carrier is added to the extract before drying. In a preferred embodiment of the invention, the carrier is diatomaceous earth which is preferably added in an amount of 1 to 60% by weight, more preferably 30 to 50% by weight, most preferably about 40% by weight of the total dry matter. The advantage of adding diatomaceous earth to the extract as a carrier before drying is that it reduces the stickiness of the extract and further neutralizes the extract. It is also possible to dry the product Q_m li without adjusting the carrier.

In preferred embodiments of the invention, birch bark extract comprises a combination of compounds or ingredients of birch bark (Betula). Typically, the raw material used for the birch bark extract is the bark of Betula pubenscens, Betula verrucosa (Betula pendula) and / or Betula papyrifera.

The solvent used for hydrolysis and / or washing is usually alcohol, acetone, cyclohexane, ethyl acetate, water or a mixture thereof. Preferably, the solvent used in the hydrolysis is an alcohol, most preferably ethanol or isopropanol. In a preferred embodiment of the invention, water is used to wash the precipitated extract of the invention. This water used for filtration and / or washing removes excess salts and other impurities from the extract.

10

The invention further relates to animal feed produced by the method of the invention described above. In preferred embodiments of the invention, the animal feed is part of a feed, preferably a complementary feed, a premix or a drinkable liquid.

The animal feed of the invention is typically administered to animals such as solipeds, ruminants and aquatic animals, preferably cows, beef cattle, pigs, poultry, sheep, goats, horses, cats, dogs, fish and crustaceans.

Another aspect of the invention is the use of birch bark extract 20 obtained or prepared by the process of the invention described above in food, animal feed, pulp, paper and board, dyes and paper coatings sealants.

A preferred embodiment for preparing the birch bark extract of the invention starts with a raw material pretreatment comprising one or more of peeling, mechanical cutting / crushing of logs, water separation, drying or residual moisture below 23%, preferably below 20%, most preferably below 15%. , and finally io temporary storage.

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In a preferred method of the invention, the solvent is added at approximately boiling point cc after the reaction vessel is filled with birch bark. Although solid-liquid extraction co 30 is preferably carried out at atmospheric pressure, it is also possible to apply pressure. extraction

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During this time, the mixture is usually maintained at reflux. The extracts are transferred from the raw material to the solvent, and the extract content is typically 2 to 5% by weight. The solvent containing the extracts, i.e. the hydrolysis fluid, is then removed from the crust residue and the 6 solvent fluid is filtered and stored in a process tank. The peel residue is washed, preferably with a pure solvent, most preferably using 80% by weight of IPA. After washing, the wash solution is also usually stored in a process tank. Preferably, the shell is steamed in a reactor or washed, for example, with water to remove the remaining solvent from the shell, followed by optional distillation of the evaporated solvent and / or vapor mixture. The solvent for washing the insoluble shell residue is optionally combined with the solvent liquid to provide a liquid phase which is subjected to further treatment. Also, the vapor mixture is optionally combined with a solvent liquid and / or a washing solvent to provide a liquid phase.

The bark residues used in the process of the invention are utilized, for example, in energy production. The bark residues are either dried or used as such.

In this preferred embodiment of the invention, the liquid phase comprising the extracts is then adjusted from basic to acidic, preferably to pH 4 to pH 2, more preferably pH 3 to pH 2, using an acid such as hydrochloric acid (HCl) or sulfuric acid (H2SO4). Although any other acid may be used, hydrochloric acid is preferred as the use of other acids may affect the taste of the feed. Another impressive factor is that sodium chloride is relatively easy to wash compared to the other salts. However, depending on the use of birch bark extract, other acids may be used. Preferably, the extracts precipitate after acidification of the liquid phase and addition of water, after which the mixture is pumped into a filter to separate the precipitated solid. Typically, some water is pumped into the filter against washing the extract and removing excess salts and other impurities.

After precipitation, the extract content is typically about 20% by weight, and therefore this slurry is preferably fed to an intermediate evaporation tank and concentrated to about 60% by weight.

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“As an extract. Evaporation can be carried out at atmospheric pressure or in vacuo and the temperature is preferably 70-90 ° C, more preferably 70-80 ° C. The concentrated liquid is then ready for dispatch to a final dryer, and the evaporated gas is preferably distilled.

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7

The final drying is carried out by conventional drying methods; preferably the dryer is a batch type vacuum dryer, most preferably a horizontal Lödige Druvatherm or spray dryer. A thin film evaporator or a rising film evaporator can also be used for drying. Typically, the carrier, preferably diatomaceous earth, is added continuously with stirring before drying, and the drying conditions are about 40 kPa (a) and 70-80 ° C.

According to a preferred embodiment of the invention, the solvents and water are reused and / or the solvent is recycled, for example, through a column of orders.

In preferred embodiments of the invention, several reaction vessels are used in succession so that the reaction vessels are in different batch stages.

Figure 1 shows a flow chart of a preferred method of the invention wherein feed 1 is fed to the reaction vessel for hydrolysis 2, followed by separation of the extracted liquid from 15 solids by washing 3 and formation of a precipitate by adjusting pH and water 4. Evaporation of the precipitated material and / or drying 6. The product is stored 7 and the solvent or aqueous mixture is distilled 8 and stored in 9 solvent storage tanks.

In the present specification and claims, the percentages or amounts of extract and / or feed are calculated based on the dry weight of solids, unless otherwise stated.

The following examples are intended to further illustrate the invention and are not intended to limit its scope. From the above description, one skilled in the art will be able to modify the invention in many ways to provide birch bark extracts of the invention.

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ϊ Reference Example 1 In accordance with Example 1 of US 2009/0182158 A1, co 30 Birch shell (15 g) was added to a 0.5 N solution of NaOH (3.5 g in 2 mL of water) and in isopropyl alcohol (IPA, 150 mL), At 50 ° C. The reaction mixture was refluxed for 3 hours and then filtered. The solid portion of the filter was refluxed with IPA (100 mL) for 0.5 h and filtered again.

8

The procedure was repeated a third time using 100 ml IPA. The isopropanol extracts were combined and the solvent evaporated to give a solid residue.

The solid residue was dried and 100 mL of heptane was added. Heptane was used instead of xylene 5 because xylene is an aromatic, carcinogenic and toxic substance and is difficult to use on a full scale. Suspending the dry solid residue in heptane was difficult due to its stackable nature and high viscosity. After boiling for 1 hour, the mixture was filtered at about 100 ° C. The solid residue recovered from the filter was boiled again. The heptane phases 10 were combined and evaporated. The yield of betulinol was 6.5%. The solid residue from the filter was subjected to further treatment.

The solid residue was acidified using a 2% solution of HCl in water (200 mL), then the solution was filtered. The solid residue recovered from the filter was washed with water (40 mL). The yield was 29.8% and consisted of 40% suberin, 35% betulinol, 25% phenol and fatty acids.

Comparative Example 2, a variation of Example 1 of US 2009/0182158 A1

Birch exterior (20 g) was added to a solution of NaOH (0.5 N) and IPA (200 ml). The reaction mixture was refluxed for 1 hour then filtered. 200 ml of water were added and the IPA was evaporated at pH 12 to give a solid residue.

The solid residue was extracted using 2 x 100 mL heptane. The heptane phases were combined and evaporated. The yield of betulinol was 2.4%. The pH of the aqueous phase was adjusted to pH 3, after which the solution was filtered. The yield of suberin and betulinol was 4.3%. The addition of water yielded very low yields of cv. Example 1 g of Betula verrucosa bark (containing about 80% by weight of dry matter, containing about 30% by weight of product extracts and additionally about 20% by weight of water) was used. and material was mechanically pre-treated by peeling the log and mechanically cutting and crushing it, after which the inner casing was separated from the outer casing by water separation, water separated, material dried by hot air to less than 23% residual moisture and transferred to an intermediate storage. The density of the raw material was 120-150 kg / m3.

9

Figure 1 shows a flow chart of a method. For hydrolysis 2, the reaction vessel was first filled with 15g of pretreated birch shell 1 and 0.5N NaOH solution (3.5g in 2ml water), followed by 150ml IPA (80% w / w, 5: 1). almost 5 at boiling point. Solid-liquid extraction was continued for 30 minutes at atmospheric pressure (reflux temperature of about 80 ° C). The solvent liquid containing the extracts was then removed from the reaction vessel and the crude residue was resuspended in 2 x 100 mL IPA (80 wt%) for 10 minutes at reflux. The reaction vessel was drained of the wash solvent and the shell was evaporated to remove the solvent. Remaining solids were removed from the reaction vessel.

The pH of the solvent phase from the hydrolysis, the washing solvent and the vapor mixture was adjusted from basic to acidic (pH 3) with hydrochloric acid (1N HCl). The same volume of water (50% by volume) (relative to the total amount of liquid from the hydrolysis, washing and steam mixture) was slowly added to the liquid phase (about 10 ml / min) 4. The extracts were precipitated from the liquid phase, followed by pumping (40 ml) was pumped into the filter at the same time as the mixture to remove excess salts and other impurities from the extract. After precipitation and washing, the extract content was 20 to about 20% by weight. This slurry was fed to an intermediate evaporation tank for evaporation (at atmospheric pressure and at a temperature of about 85-90 ° C) and concentrated to about 60% by weight of extract 6. The extract was almost completely free of IPA and contained water. The evaporated gas was filtered 8 and the concentrated extract was pumped into a horizontal Lödige Druvatherm dryer 6 (at a pressure of about 40 kPa (a) and a temperature of about 70-80 ° C). 40% by weight of the total amount of materials dried while stirring continuously. The extract had a solids content of more than 80% by weight. The yield of the brownish extract obtained by the process of the invention 7 was 42.4% 3 and comprised about 26% by weight of suberin fatty acids, 58% betulinol and 16% | phenolic complexes. The solvent (IPA, 80 wt.%) Was recycled through the distillation column 8 and the co 30 further to the solvent storage 9. In addition, as much water as possible was reused.

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The present invention has been described herein with reference to specific embodiments. However, it will be apparent to one skilled in the art that the process or methods may be modified within the scope of the claims.

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Claims (10)

A process for the recovery of birch bark extracts, the process comprising the steps of: a) exposing birch bark to hydrolysis using solvent-containing hydrolysis liquid; b) separating undissolved bark portions from the solvent liquid remaining after step a), c) providing (d) precipitation of extracts from said liquid phase by increasing the relative amount of water to between 30-70 wt.%, more advantageously 55-65 wt.%, mesi advantageously. about 60% by weight of water of the total amount of liquids; and f) extracting the extract. Process according to Claim 1, characterized in that, in step b), the undissolved bark part is washed with solvent, the solvent is separated and the separated solvent is combined with the solvent liquid in step c) to provide said liquid phase. 3. A process according to claim 1 or 2, characterized in that said undissolved bark portion in step b) is indicated to remove solvent, a meadow mixture is separated from the bark residues and said meadow mixture is combined with the solution liquid in step c) to provide said liquid phase. o c \ j 2- 25 4. A process according to any one of the preceding claims, characterized in that said liquid phase is acidified to a pH from 4 to pH 2, more advantageously from x pH 3 to pH 2. CL A process according to claim 1, characterized in that said increasing of the relative amount of water during step d) is achieved by adding water and / or by evaporation of the solvent from the acidified liquid phase. 6. A process according to claim 5, characterized in that, 30-70 wt.%, More advantageously 45-55 wt.%, Most advantageously about the same volume of water as the volume of the liquid phase is added in said liquid phase. 7. A process according to any one of the preceding claims, characterized in that said solvent used for hydrolysis and / or washing is one or more of alcohol, acetone, cyclohexane, ethyl acetate, aqueous or mixtures thereof, advantageous alcohol, most advantageously ethanol. or isopropanol. 8. A method according to which, according to the preceding claims, characterized in that said birch bark is mechanically processed before said hydrolysis, advantageously by barking logs, making chips, crushing, grinding, grinding, grinding or any other heist combination thereof. 9. A process according to claim 1, characterized in that said extraction of said extract comprises drying and adding carrier to the extract prior to drying. 15 10. A method according to any one of the preceding claims, characterized in that said carrier is diatomaceous earth, advantageously added in an amount of 1-60 m%, more advantageously 30-50 m%, most advantageously about 40 m% of total amount of dry matter. co δ CvJ o CvJ X X Q. CO δ m δ CvJ