Jauna ekstrakcijas metode augsta betulīna satura ekstraktvielu iegūšanai

Uzlabojot iepriekš zināmas bērza tāss pārstrādes tehnoloģijas, izstrādāta jauna metode un patentēta pilotiekārta ķīmiska savienojuma - betulīna izdalīšanai ar augstu iznākumu un tīrību vienkāršā, efektīvā ekstrakcijas procesā, kuru varētu mērogot uz liela apjoma rūpniecisko ražošanu Latvijā. Tādā veidā ir radīta iespēja būtiski uzlabot bērza koka izmantošanas efektivitāti un Latvijā svarīgās finierrūpniecības nozares produkcijas kopējo pievienoto vērtību. Intensīvās masas apmaiņas ekstrakcijas pilotiekārta ir speciāli pielāgota, lai izdalītu augstas tīrības (90,1%) betulīnu no nepolāro ogļūdeņražu šķīduma, kas procesa gaitā izgulsnējas iekārtai pievienotajā starpkristalizātorā. Izmantojot vairākus efektīvus ekstrakcijas intensifikācijas un bērza tāss apstrādes paņēmienus, izstrādāts optimāls režīms, lai no rūpnieciskās tāss granulu frakcijas ar izmēru 0,4-2,0 mm varētu izolēt gandrīz maksimālo betulīna daudzumu (22,9% no a.s. tāss masas). Un tālāk, pielietojot vienkāršas betulīna atdalīšanas un pārkristalizācijas operācijas, iegūts analītiski tīrs (>96,6%) betulīns un lupeola koncentrāts, kuru var izmantot individuāla savienojuma izdalīšanai. Pētījumu procesā radīta jauna bērza tāss kvalitātes kontroles metode, ar kuru operatīvi var noteikt lūksnes piemaisījuma saturu pēc parauga sadegšanas siltuma. Apspriesti racionāli betulīna un bērza mizas pārstrādes atlikumu izmantošanas varianti, kā arī piedāvāts betulīna un lupeola rūpnieciskās ražošanas tehnoloģiskais priekšlikums

Petroleum Ether - Most Appropriate Solvent for Isolation of Betulin from Birch Outer Bark

In the industrial processing of birch wood as a by-product accumulates birch outer bark (BOB) which often is burned as a fuel. However, birch bark can also be a promising raw material for compounds with a very broad range of applications - in the field of pharmaceutical, cosmetic, food and material science. In recent decades, attention of scientists has deserved lupane type pentacyclic triterpenes. Betulin is main representative of triterpenes in BOB. Birch bark comprises about 12.50 wt.% of the tree mass from which up to 3.40% is outer bark which contains 25% of betulin. Such a high content of individual compound in natural resources is very uncommon; therefore it makes the isolation of betulin from birch outer bark economically favourable on an industrial scale. Non-polar hydrocarbons is referred as most selective solvents for isolation of betulin in the extraction process [1]. Therefore, it is necessary to choose the best solvent taking into account important factors such as price, toxicity, etc. Experimental studies showed that the most suitable solvent for the extraction of BOB is petroleum ether with a boiling range of 100-140°C (PE140). It consists of a mixture of hydrocarbons, mainly of heptane, octane, nonane, decane, with an average density of 0.74 kg/m3

Analytical Control of the Process of Preparing Lignocellulose for Obtaining Levoglucosan

The yield of the main product of the thermal destruction of cellulose - 1,6-anhydro-β,D-glucopyranose or levoglucosan (LG) in the fast thermolysis of hardwood increases several times, if pre-hydrolysis of wood in the presence of a sulphuric acid catalyst at the temperature 150 -155°C is carried out, thereby achieving the hydrolysis of the main part of hemicelluloses. The lignocellulose (LC) obtained after washing are also the LG raw material. In the study, the chemical composition of the intermediate products formed in the technological process of preparing LC as well as the degree of polymerisation (DP) of cellulose in wood and the obtained LC are investigated. A possible correlation between the DP and the LG yield is discussed. The component composition is determined, and the applicability and purification potentialities of the obtained intermediate products – prehydrolysis condensates and LC washing waters are evaluated. The pre-hydrolysis process condensate contains a considerable amount of acetic acid and furfural, namely, 5% and 12% from the oven dry wood mass, respectively. The obtained LC chips are washed with water till the pH 2.0-2.2 or the H2SO4 concentration from oven dry LC about 0.1% from its mass. 19-21% of oven dry wood organic substances, from which 78-88% are monosaccharides, are diluted in the washing waters. After the washing, the LC yield is 52-55% in terms of oven dry wood. During the pre-hydrolysis, as a result of the action of sulphuric acid and elevated temperature, the DP of cellulose decreased from 1800-1900 in alder wood to 1200-1400 in LC. Comparing the LG yields from Kuerschner cellulose preparations prepared from the initial wood and LC, a considerably higher LG yield is obtained from the latter. The thermolysis with the corresponding wood and LC samples, carried out in parallel, has shown that the acid-treated material (LC) demonstrated considerably higher LG yields, which, taking into account the cellulose content in LC (45-55%), actually correspond to the LG yield from the corresponding Kuerschner cellulose preparation. The use of the condensate for obtaining furfural and acetic acid is technically feasible. The applicability of the LC washing waters is still under study, although they do not present any problems in the wastewater biological treatment facilities

Levoglikozāna iegūšanas procesa analītiska kontrole

Celulozes termiskās noārdīšanas galvenā produkta 1,6-anhidro-β,D-glikopiranozes jeb levoglikozāna – (LG) iznākums lapukoku koksnes ātrajā termolīzē daudzkārt palielinās, ja veic koksnes priekšhidrolīzi sērskābes katalizatora klātbūtnē 150-155°C temperatūrā, ar ko panāk hemiceluložu hidrolīzi. Pēc skalošanas iegūtā lignoceluloze (LC) tad arī ir LG izejviela. Darbā pētīts LC pagatavošanas tehnoloģiskajā procesā radušos starpproduktu ķīmiskais sastāvs un celulozes polimerizācijas pakāpe (PP) koksnē un iegūtajā LC. Apspriesta celulozes PP un LG iznākuma iespējamā korelācija. Noteikts komponentu sastāvs un novērtētas iegūto starpproduktu – priekšhidrolīzes kondensātu un LC skalošanas ūdeņu izmantošanas un attīrīšanas iespējas. Priekšhidrolīzes procesa kondensāts satur ievērojamu daudzumu vērtīgās etiķskābes un furfurola – attiecīgi 5% un 12% no absolūti sausas koksnes masas. Pāri palikušo LC skalo ar ūdeni līdz pH 2,0-2,2 jeb H2SO4 koncentrācijas absolūti sausā CL ap 0,1% no tā masas. Skalošanas ūdeņos izšķīst 19-21% no absolūti sausas koksnes organisko vielu no kurām 78-88% sastāda monosaharīdi. Pēc skalošanas LC iznākums ir 52-55%, rēķinot no absolūti sausas koksnes. Priekšhidrolīzes laikā sērskābes un paaugstinātas temperatūras iedarbības rezultātā celulozes PP no 1800-1900 alkšņa koksnē pazeminājās līdz 1200-1400 LC. Salīdzinot LG iznākumus no Kiršnera celulozes preparātiem, kas pagatavoti no izejas koksnes un LC, ievērojami augstāks LG iznākums iegūts no pēdējā. Paralēli veiktās termolīzes ar atbilstošās koksnes un CL paraugiem parādīja, ka ar skābi apstrādātais materiāls uzrādīja daudz augstākus LG iznākumus, kuri, ņemot vērā celulozes saturu LC (45-55%), faktiski atbilda LG iznākumam no atbilstošā Kiršnera celulozes preparāta. Kondensāta izmantošana furfurola un etiķskābes iegūšanai ir tehniski iespējama. LC skalošanas ūdeņu izmantošanas iespējas vēl tiek pētītas kaut arī notekūdeņu bioloģiskās attīrīšanas iekārtās tie sarežģījumus neradītu

Isolation of Triterpene-Rich Extracts from Outer Birch Bark by Hot Water and Alkaline Pre-Treatment or the Appropriate Choice of Solvents

Birch bark, left over as residue fuel in the pulp and plywood industry, is rich in pentacyclic lupane-type triterpenes – primarily betulin and lupeol – promising starting materials for the synthesis of biologically active compounds with a broad spectrum of medical applications. A comparative study on the main triterpenes of the outer bark of two birch species – silver birch (Betula pendula Roth.) and downy birch (Betula pubescens Ehrh.) – is reported. The total yield of extractives decreased with crop age. For the first time, pre-treatment with hot water and Na2CO3 water solution of birch outer bark was carried out before extraction. Pre-treatment with Na2CO3 water solution substantially improved the ethanol extracts’ triterpene content (from 67.7 to 99.0%). The effect of different solvents on the yield and composition of extracts was studied. Nonpolar solvents behave more selectively toward triterpenes and admixtures. It is possible to improve the extracts’ triterpene content by modifying the extraction technology employed and choosing the appropriate solvents

Isolation of Suberinic Acids from Extracted Outer Birch Bark Depending on the Application Purposes

The research applies to the woodworking industry and the utilisation of bark for obtaining of saturated higher fatty acids, containing reactive hydroxyl and epoxy groups, which are promising raw materials for the synthesis of high added value derivatives for cosmetics, emulsion production, the polymer industry, etc. Therefore, the application of the results of our investigation has synergy with material science. The aim of the investigation was to increase the utilization efficiency of birch bark and to inform the specialists of the forestry and wood industry about the wide scope of high added value products, which could be produced from this valuable raw material. The fractionation of suberinic acids by sedimentation in certain ranges of the alkaline-alcohol solution pH 4.7-6.0 made it possible to obtain suberinic acids with the content of 9,10-epoxy-18-hydroxy octadecanoic acids up to 58% oven dry suberinic acids fraction. The mixture of suberinic acids obtained by alkaline-water depolymerisation acts as an excellent binding agent to produce medium and high density formaldehyde free particle boards with low thickness swelling and high bending strength. The biobased rigid polyurethane foams obtained from suberinic acids polyols also demonstrate good mechanical properties

Isolation of Suberinic Acids from Extracted Outer Birch Bark Depending on the Application Purposes

The reasearch applies to silviculture and the utilization of wood matrial (bark) for obtaining of triterpenes and saturated higher fatty acids, conataining reactive hydroxyl and epoxy groups, which are used to sythesize high added value derivatives for pharmacy, cosmetics, agriculture, the spirits industry, emulsion production, the polymer industry etc

Polyurethane Foam from Industrial Waste of Plywood Production

This study shows the possibility of using birch bark, a by-product of plywood production, for preparing polyurethane foam. A birch bark lignocellulose component – inner bark – was liquefied to obtain a polyurethane raw material – polyol mixture. Outer bark, containing valuable biologically active pentacyclic triterpenes (betulin, lupeol, betulinic acid, etc.), after extracting those compounds, was subjected to hydrothermal treatment in alkaline medium, and the other main inner bark component – suberin – was depolymerised. The obtained suberinic acid triethanolamine ester, as a polyol component, was used for polyurethane foam synthesis. Both types of polyols gave polyurethane foams with good physical properties. Such a complex approach has shown that it is possible to prepare new products with a high added value from waste natural raw materials