Análise da madeira de Pinus oocarpa parte I: estudo dos constituintes macromoleculares e extrativos voláteis

Morais, Sérgio Antônio Lemos de; Nascimento, Evandro A.; Melo, Dárley Carrijo de

doi:10.1590/s0100-67622005000300014

Cited by 72 publications

(47 citation statements)

References 11 publications

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“…The water-soluble wood constituents are mainly salts or inorganic minerals, sugars, and polysaccharides of low molar mass (MORAIS; NASCIMENTO; MELO, 2005). The wood pore clearance is important because it can increase permeability, and also positively influence the drying process, therefore decreasing defects and raising the drying tax, making it more economic.…”

Section: Resultsmentioning

confidence: 99%

Effect of Hydrothermal and Freezing Treatment on the Physical and Mechanical Properties of Eucalyptus Wood

et al. 2017

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-Wood, in general, is a material with excellent properties; however, some features may limit its use. In this sense, various thermal treatments are emerging as alternatives to improve the technological properties of wood. In this context, this study aims at analyzing the effects of time and temperature (hydrothermal treatment and freezing) on the physical and mechanical properties of Eucalyptus grandis W. Hill ex Maiden. Three trees were selected, and only the heartwood was used to obtain the test body dimensions of 30 × 8 × 3 cm (length × width × thickness). The treatments were carried out at three temperatures of -20, 60, and 100°C, each at three exposure times (5, 10, and 15 h). Temperature treatment at -20°C was conducted in a domestic freezer, while the treatments at 60 and 100°C were administered in a Parr reactor, where the timber was submerged in water. Regardless of the exposure time, the timbers heat-treated at 100°C showed more efficiency, since this treatment unclogged the pores, reduced hygroscopicity, and promoted further darkening and uniformity of color, without changing the density and mechanical strength of the wood. Keywords:Heartwood. Parr reactor. Heat treatment. EFEITO DO TRATAMENTO HIDROTÉRMICO E CONGELAMENTO NAS PROPRIEDADES FÍSICAS E MECÂNICAS DA MADEIRA DE EUCALIPTORESUMO -A madeira, de modo geral, é um material com excelentes propriedades, mas ressalta-se que algumas características podem limitar o seu uso. Neste sentido, alguns métodos de tratamentos térmicos vêm surgindo como alternativa para melhorar algumas propriedades tecnológicas da madeira. Neste contexto, o objetivo do trabalho foi avaliar o efeito do tempo e da temperatura do tratamento hidrotérmico e do congelamento nas propriedades físicas e mecânicas da madeira de Eucalyptus grandis W.Hill ex Maiden. Foram utilizadas três árvores, selecionando-se apenas a madeira do cerne para obtenção dos corpos de prova de dimensões 30 x 8 x 3 cm (comprimento x largura x espessura). Os tratamentos foram realizados nas temperaturas de -20, 60 e 100 °C combinados a três tempos de exposição (5, 10 e 15 horas). O tratamento na temperatura de -20 °C foi realizado em um freezer doméstico, e os tratamentos a 60 e 100 °C em um Reator Parr, onde as madeiras ficaram submersas em água. Independente do tempo de exposição, os tratamentos realizados a 100 °C mostraram-se mais eficientes, pois desobstruíram os poros, reduziram a higroscopicidade e promoveram maior escurecimento e homogeneização da cor das madeiras, sem alterar a densidade e a resistência mecânica das mesmas.Palavras-chave: Madeira de cerne. Reator parr. Tratamento térmico.

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Section: Resultsmentioning

confidence: 99%

Effect of Hydrothermal and Freezing Treatment on the Physical and Mechanical Properties of Eucalyptus Wood

et al. 2017

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“…Algumas dessas substâncias como os polifenóis e os taninos, possuem propriedade germicida e são responsáveis pela durabilidade natural de muitas madeiras, em especial de clima tropical, como a aroeira (Farmer, 1967;Morais et al, 1999;Morais et al, 2002;Morais et al, 2005). Os taninos ocorrem amplamente nos vegetais, porém, sua extração comercial é feita por meio da casca e/ou do cerne da madeira.…”

Section: ____________________________________________________unclassified

“…O óleo essencial obtido foi submetido à análise por cromatografia gasosa acoplada à espectrometria de massas (CG/EM) (Nascimento et al, 1996;Morais et al, 2005). O cromatograma apresentado é, portanto, de íons totais.…”

Section: Obtenção Do óLeo Essencialunclassified

Estudo dos constituintes macromoleculares, extrativos voláteis e compostos fenólicos da madeira de candeia – <i>Moquinia polymorpha</i> (Less.) DC.

Lima

Oliveira²,

Morais³

et al. 2007

Ciênc. Florest.

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RESUMONeste estudo, foram analisados os principais componentes químicos da madeira da Moquinia polymorpha (LESS.) DC., conhecida como candeia ou cambará, nativa da região Sul de Minas Gerais. A composição química dessa madeira foi: 47,5% de α-celulose, 25,4% de hemiceluloses A e B, 24,0% de lignina, 73,2% de holocelulose, 3,82% de extrativos em etanol:cicloexano (1:1, v v -1 ), 3,21% em etanol e 4,04% em água quente. Nos compostos voláteis identificados, destacaram-se: ABSTRACTIn this study, the main chemical components of Moquinia polymorpha (LESS.) DC. (candeia or cambará) wood were investigated. This wood is native in the Southern region of Minas Gerais -Brazil. The chemical composition was: 47.5% of α-cellulose, 25.4% of A and B hemicelluloses, 24.0% of lignin, 73.2% of holocellulose, 3.82% of ethanol:cyclohexane (1:1, v v -1 ) extractives, 3.21% of ethanol extractives and 4.04% of hot water extractives. The volatile composition was mainly: α-curcumene, α-dihydroturmerone, β-dihydroturmerone, cedranol, 1-cyclopentyl-3-[2,4-dimethylphenyl]propane. The total phenols analysis was carried out on methanol:water (MW) and acetone:water (AW) extracts. The last one presented better yield. The total phenols were determined by Folin-Ciocalteau and the modified Prussian blue assays. FolinCiocalteau yielded 0.93 mg g -1 of wood for MW extract and 1.56 for AW extract; modified Prussian blue yielded 2.74 mg g -1 of wood for MW extract and 4.42 for AW extract. Proanthocyanidins were determined by n-buthanol-acid and vanillin assays. The n-buthanol acid yielded 0.012 mg g -1 of wood for MW extract and 0.017 for AW extract; vanillin: 0.29 mg g -1 of wood for MW extract and 0.58 for AW extract. 3-deoxyproanthocyanidins were not detected.

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“…Galactoglucomannans (GGM) is the main hemicellulose in softwoods, with approximately 15-30% of the wood composition (WILFÖR et al, 2005, MORAIS et al, 2005. Galactoglucomannans could be a potential source of fermentable sugars for ethanol production inasmuch as, according to Gottschalk (1947), the six carbon monosaccharides, D-galactose, D-glucose and D-mannose, can be directly fermented by yeasts to ethanol.…”

Section: Introductionmentioning

confidence: 99%

Extração e caracterização de hemiceluloses de Pinus radiata e sua viabilidade para a produção de bioetanol

Reyes¹,

Mendonça²,

Aguayo³

et al. 2013

Rev. Árvore

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-Galactoglucomannans are the major hemicellulosic fraction present in softwoods, and is mainly composed by the hexoses: galactose, glucose and mannose. The efficient and selective isolation of these hemicelluloses is regarded as one of the most critical obstacles to overcome for their utilization. The objective of the current work was to extract and characterize acidic and neutral aqueous solutions of hemicelluloses from Pinus radiata wood chips and investigate their feasibility for bioethanol production. Hemicelluloses in P. radiata represented 26 g/100 g wood (o.d.w.) and hexoses are responsible for approximately 64% of this amount. According to the different extraction conditions, approximately 50% of the hemicellulosic fraction was solubilized and recovered after precipitation with ethanol. The recovered hemicellulosic fractions were in the form of oligomers with weight-average molecular weigth (M w ) varying from 4x10 3 to 4x10 5 g/mol. Hemicellulosic oligomers were hydrolyzed with dilute sulfuric acid and the hydrolysates concentrated until approximately 70 g/L of hexoses and fermented by Saccharomyces cerevisiae yeast. Fermentation results showed that sugar obtained from acid and neutral extractions were fermented to ethanol with maximum yields of 63% and 54% (22 g/ L and 19 g/L), respectively. The conversion of wood hemicellulosic substrates to ethanol is feasible but the low ethanol yields obtained make the process not economically attractive and optimization of the process or alternatives uses for hemicelluloses should be evaluated.Keywords: Pinus radiata, Hemicelluloses, Bioethanol. EXTRAÇÃO E CARACTERIZAÇÃO DE HEMICELULOSES DE Pinus radiata E SUA VIABILIDADE PARA A PRODUÇÃO DE BIOETANOL

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Análise da madeira de Pinus oocarpa parte I: estudo dos constituintes macromoleculares e extrativos voláteis

Cited by 72 publications

References 11 publications

Effect of Hydrothermal and Freezing Treatment on the Physical and Mechanical Properties of Eucalyptus Wood

Effect of Hydrothermal and Freezing Treatment on the Physical and Mechanical Properties of Eucalyptus Wood

Estudo dos constituintes macromoleculares, extrativos voláteis e compostos fenólicos da madeira de candeia – <i>Moquinia polymorpha</i> (Less.) DC.

Extração e caracterização de hemiceluloses de Pinus radiata e sua viabilidade para a produção de bioetanol

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