Mualla Balaban Uçar

Composition of Volatile Foliage Isolates from Cupressus sempervirens Varieties (Var. horizontal Mill. and pyramidalis Nyman) Growing in Turkey

Abstract In order to differentiate two varieties of Cupressus sempervirens, volatile foliage isolates obtained from 12 trees of variety horizontalis and 12 trees of var. pyramidalis were analyzed by GC and GC/MS. About 86–87% of total peak areas of chromatograms consist of monoterpenes and evaluating their composition in qualitative and quantitative manner they do not show significant differences with regard to varieties. Some increments of terpinen-4-ol, α—terpineol and α—terpinyl acetate was recognizable in the variety horizontalis, while the variety pyramidalis contained germacrene D and abietadiene to somewhat higher level. On the other side, a higher percentage of α—fenchene than that of camphene and the presence of a monoterpene hydrocarbon sylvestrene were found to bear some chemotaxonomic value for the taxon C. sempervirens.

A comparative study on the chemical composition of the oriental spruce woods Picea orientalis from planted and natural forests

The main constituents and cyclohexane extractives of wood obtained from planted and native oriental spruce, P. orientalis, were comparatively investigated. The plantation stand in Belgrad Forest near the city Istanbul is about 1000 km west to the original provenance in northeast Turkey with somewhat different environmental factors. The distribution of the main components and the total extractive contents in the woods were affected insignificantly. Only few differences were notable in the amount of sugar monomers of the main polyoses, mannan and xylan, when the native and planted woods were subject to total hydrolyses. The yield of lipophilic extractives in native and planted woods was almost the same. The composition of lipophilic extractives of the woods, determined after proper derivatization by GC-MS, were also not different qualitatively, but some constituents exhibited quantitative changes. Although the planted wood contained significantly more resin acids, sterols, and alcohols, the natural samples had more unsaturated fatty acids.

Characterization of methanol extracts from Quercus hartwissiana wood and bark

The MeOH extracts of wood and bark from Quercus hartwissiana have been investigated by GC-MS after derivatization, as well as by classical spectroscopic methods. The results for the free compounds revealed that ellagic acid, catechin, gallic acid, quercitol, and also long chain fatty acids, sugars, and sitosterol were the essential compounds in wood and bark, most of them being present in differing amounts. Quercitol, a characteristic compound for the oak wood tannin, was also recognized and determined in oak bark extracts in this study. Amounting to 1/4th to 1/3rd of the free compounds, the bark had the highest catechin content. While the content of sugars, such as fructose and glucose, increased in sapwood and bark extracts remarkably, the amounts of these compounds decreased in extracts of heartwood. The profile of the bound compounds contained sugars (i.e., arabinose, xylose, and, above all, glucose), ellagic and gallic acids, quercitols, and inositols. Compared with the composition of free compounds, the hydrolyzed extracts showed relatively higher amounts of sugars, especially glucose, gallic acid and quercitol.

NaBH4 Pretreatment in Bioethanol Production of Corn Stalks

Abstract Corn stalks, which are an abundant agricultural waste product in Turkey, have a high carbohydrate structural content and could be a valuable raw material for bioethanol production. In this study, stalks with crystalline cellulose and complex lignin and hemicellulose distribution in their structure were first steam-exploded and then chemically treated to achieve efficient hydrolysis. The conventional chemicals sodium hydroxide (NaOH), sulfuric acid (H2SO4), hydrogen peroxide (H2O2), and an alternative chemical, sodium borohydrate (NaBH4), were utilized in the chemical treatment procedure. Results showed that the samples treated with NaOH (83.9%) and NaBH4 (82.9%) gave higher glucan conversion in enzymatic hydrolysis compared to those treated with H2O2 (74.5%) and H2SO4 (56.6%). The highest ethanol yield from untreated stalks (97.4 g/kg) was obtained when the stalks were pretreated with 4% NaBH4 for 90 min; the theoretical ethanol yield was found to be 72.5%.

The Estimation of Acidic Behavior of Wood by Treatment with Aqueous Na(2)HPO(4) Solution.

As a new approach, the acidity that wood exhibits under moderate conditions is assayed by stimulated dissociation of weak wood acids in lightly basic secondary phosphate solutions. To assure a sufficient dissociation of hardly soluble weak acids in the solution, the amount of wood suspended in Na2HPO4 solutions should be small but vary depending on the degree of acidity of wood species. However, the difficulties are associated with the titration of very dilute acids limiting the precision of the measurement. If the disintegrated wood is suspended in a secondary phosphate solution, the weak woods acids form the conjugate acid Na2HPO4 from secondary phosphate Na2HPO4 resulting in a pH fall of the solution. The decrease in the pH value in phosphate solution, which depends on the wood acidity, can be evaluated to estimate the acidity arising from wood under moderate conditions.

Doğu ladini ve meşe kabuklarından tanen ekstraksiyon aşamasının optimize edilmesi

Ulkemizde ormancilik faaliyetleri sonucunda ve ahsap levha ureten sanayi kuruluslarinda uretim prosesi sonucunda onemli miktarda atik durumunda kabuk ortaya cikmaktadir. Yakilmak disinda degerlendirilmeyen bu atik kabuklarin tanen bakimindan zengin oldugu bilinmektedir. Kabuklardan tanen eldesinde kullanilan cozucu turu, ekstraksiyon yontem ve parametrelerinin optimize edilmesi kritik onemdedir. Dogru ekstraksiyon parametreleri ile gerceklestirilen ekstraksiyonlar ile tanende ekstraksiyon asamasinda ortaya cikabilecek otokondenzasyon reaksiyonlari, yuksek sicaklik kaynakli termal bozunma etkileri, ekstrakt safliginin ve reaktivitesinin azalmasi gibi olumsuzluklar onlenebilir. Bunlarin yaninda ekstraksiyon optimizasyonu islemi ile daha kisa surede daha az cozucu ve enerji kullanimi ile verimlilik artirilabilir. Bu calismada, orman isletmelerinde kesim sonrasi ortaya cikan dogu ladini (Picea orientalis) kabuklari ve ahsap levha endustrisinde levha uretimi sonrasi ortaya cikan endustriyel atik mese (Qercus spp.) kabuklari su, farkli oranlarda sodyum sulfit (Na2SO3), sodyum karbonat (Na2CO3), ure (CH4N2O) ve bunlarin karisimini iceren sulu cozeltiler ile 70°C ve 100°C ekstraksiyon sicakligi, 1/6, 1/8 ve 1/10 kabuk:cozucu oraninda, 1, 3, ve 5 saat ekstraksiyon suresi gibi parametreler kullanilarak ekstraksiyonlar gerceklestirilmistir. Ekstraksiyon cozeltilerinde verim, stiasny sayisi ve pH degerleri belirlenmistir. Elde edilen sonuclara gore, ladin ve mese kabuklari icin % 2 sodyum sulfit+% 0.50 sodyum karbonat cozeltisi ile 1/8 kabuk cozucu oraninda ve 1 saat ekstraksiyon suresinde optimum sonuclar elde edilmistir. Kabuk ekstraksiyon cozeltileri pH degerleri, sicak su ekstraksiyon cozeltilerinde pH 4.5 civarinda iken sodyum sulfit ve sodyum karbonatli cozeltilerin pH’i 7 civarindadir.

Composition of Essential Oils from Fir (Abies) Wood Species Grown in Turkey

Abies species naturally grown in Turkey are represented by four species and two subspecies. Abies equi-trojani (Aschers & Sint.) and Abies bornmulleriana (Mattf.) occur in western and northwestern regions. Abies cilicica subsp. isaurica (Coode & Cullen) and Abies cilicica subsp. cilicica (Antoine & Kotschy) Carr. are widespread in the southern part of the country (on Taurus mountains), and Abies nordmanniana (Steven) Spach is native in the eastern Black Sea region of Anatolia [1]. The main cell wall constituents (lignin, polysaccharides) of the woods from these species were studied by Ozdemir [2]. However, there have been no reports on the constituents of wood essential oils of Anatolian Abies species. On the other hand, Abies woods characteristically contain juvabiones, which are insect juvenile hormone related compounds. As a group of sesquiterpenoids, juvabiones and dehydrojuvabiones have been investigated in some fir woods [3–9]. In the present study, the components of the essential oils isolated from the woods of Anatolian fir species by hydrodistillation were analyzed and compared with one another. Two representative trees from each of a total of ten regions were felled to collect wood samples; A. bornmulleriana: Bolu and Uludag; A. equi-trojani: Kalkim and Gurgen; A. cilicica subsp. cilicica: Andirin and Goksun; A. cilicica subsp. isaurica: Bucak and Akseki; A. nordmanniana: Artvin and Torul. The essential oil yields of Anatolian fir woods were remarkably low, in the range 0.01–0.02%. GC-MS results of the essential oils from fir woods are shown in Table 1. Generally, fir essential oils exhibited large differences in both the composition and percentages of compounds between species and from tree to tree. Even within the same region and species, the essential oil composition could vary greatly. Therefore, in this study the composition of fir wood essential oils is given in the compound classes with special emphasize on juvabiones. As can be seen from Table 1, sesquiterpenes are present in the highest percentages in many fir woods. In particular, juvabiones and nerolidol were the main compounds among the sesquiterpenes, and these compounds together with fatty acids constitute a high percentage in some fir species. The monoterpenes often occur in small quantities, and some diterpene related compounds in trace amounts were recorded in fir woods. The monoterpenes varied widely both in their content and chemical structures. It is well known that juvabiones are characteristic compounds for Abies species. As expected, juvabione, dehydrojuvabione, and dihydrojuvabione were detected also in the essential oils of Anatolian fir woods. Both juvabione and dehydrojuvabione concentrations had large variations among the tested trees. This finding is in good agreement with the literature showing that the juvabiones in fir woods can vary considerably in a qualitative and quantitative manner among trees within the same species [3–6, 10]. In our case, juvabione was present in larger amounts than dehydrojuvabione in all 20 trees. This finding is contradictory to the data of [11] who reported that the extract of A. fraseri had a higher amount of dehydrojuvabione than juvabione. It is of interest to note that the Table 1 shows larger variations in juvabione, dihydrojuvabione, and dehydrojuvabione concentrations in fir woods. Similar results were reported for A. balsamea [3], A. alba [4], A. lasiocarpa [5], A. sachalinensis [6], and A. bifolia [10]. These authors studied the juvabiones isolated from hexane or petroleum ether extracts of fir woods and elucidated the structure of these compounds by different techniques. However, in our study the juvabiones were isolated from the oily layer of the water distillates obtained by hydrodistillation. The juvabione content of Abies fraseri woods under intact and infested condition attacked by balsam woody adelgid was studied. The results showed that infested firs had higher mean juvabione levels than uninfested trees [11].

Influence of plum gum and sodium perborate addition on spruce kraft pulp properties during oxygen delignification

The aim of this study was to investigate the effects of plum gum liquor and sodium perborate addition to oxygen delignification process on spruce kraft pulp properties. Yields and viscosity of pulp were protected against oxidative attack, when kappa number of pulp was not changed by adding plum gum to oxygen delignification process. Delignification ratio improved by 7.4% without any viscosity loss by adding only 0.25% sodium perborate as active oxygen with plum gum liquor to the oxygen delignification process. It was found that crystallinity of pulp was improved by adding plum gum and sodium perborate to oxygen delignification. It was also determined that sodium perborate had an affirmative effect on delignification ratio, when plum gum affected pulp viscosity positively.

Effect of ethyl acetate on carbohydrate components and crystalline structure of pulp produced in aqueous acetic acid pulping

The aim of this study was to investigate the changes in carbohydrate components and the crystalline structure in hemp bast fibers by adding ethyl acetate to acetic acid/water pulping processes. It was found that ethyl acetate added to acetic acid/water process had a positive effect on yield, viscosity and carbohydrate components in pulp. It was assumed that the delignification ratio increased by adding ethyl acetate to aqueous acetic acid pulping. Xylose content in hemp bast fibers was affected more negatively in the ethyl acetate/acetic acid/water process than in the acetic acid/water one. Crystallinity and crystallite size were higher in pulp sample obtained by the acetic acid/water process without ethyl acetate.