Wasrin Syafii

Erythro/threo ratio of β-O-4-5 structures as an important structural characteristic of lignin. Part 4: Variation in the erythro/threo ratio in softwood and hardwood lignins and its relation to syringyl/guaiacyl ratio

Abstract The proportion of erythro- and threo-forms of β-O-4-structures in lignin was elucidated by ozonation analysis of 21 wood species, and the relationship to the syringyl and guaiacyl composition was investigated. For all hardwood species, the erythro-form of β-O-4-structures predominated, although the extent varied widely, depending on wood species. In contrast, the proportion and amount of erythro- and threo-forms were very similar in all softwood species. The proportion of the erythro-form was greater in species with a higher methoxyl content in the lignin (correlation coefficient, R2=0.83). The S/V ratio (molar ratio of syringaldehyde and syringic acid to that of vanillin and vanillic acid) obtained by nitrobenzene oxidation was also strongly correlated with the proportion of the erythro-form (R2=0.99). Accordingly, the syringyl/guaiacyl ratio is closely related to the erythro/threo ratio. This stereochemical characteristic of β-O-4-structures is discussed in relation to the process of lignin formation.

Characteristics of guaiacyl-syringyl lignin in reaction wood in the gymnosperm Gnetum gnemon L.

Abstract Gnetum gnemon L. is a unique gymnosperm species showing angiosperm-like features in terms of its morphology and chemical composition of the cell wall. Xylan is the main hemicellulose component, and its lignin is primarily composed of syringyl (S) and guaiacyl (G) units and small amounts of p-hydroxyphenyl (H) units. In the present study, in addition to branch, root, bark, and leaf samples, the reaction wood (RW) taken from the leaning stem of G. gnemon, was investigated mainly by alkaline nitrobenzene oxidation, ozonation and NMR spectroscopy. The leaning stem was wider on the lower side of the wood stem (lsW) than on the upper side (usW), similar to the case for compression wood (CW) in gymnosperms. The usW contained lignin with a higher S/G ratio, and β-O-4 structure had a higher erythro/threo ratio, while both ratios decreased around the periphery of the stem towards the lsW. The lignin content was higher towards the lsW. Overall, the lignin composition in the RW of this tree was similar to that in the tension wood of angiosperms. The H-units were minor components in the lignin, but the content was higher towards the lsW, which resembles the distribution of the H-units in a gymnosperm CW.

Characteristics and Reactivity of Lignin in Acacia and Eucalyptus Woods

The chemical characteristics of lignin, including the Klason lignin content, acid-soluble lignin content, proportion of the aromatic ring types [syringyl ratio = syringyl/(syringyl + guaiacyl)], and proportion of the diastereomeric forms for the β-O-4 structure [erythro ratio = erythro/(erythro + threo)], and pulpability were investigated for 28 wood samples belonging to the genera Acacia and Eucalyptus. Although the lignin characteristics of these 28 woods varied widely, the chemical characteristics of the two genera could be categorized in two clearly distinguished groups on the basis of the syringyl ratio. Clear negative correlations were observed between both the syringyl and erythro ratios and the total lignin content (sum of the Klason and acid-soluble lignin contents) within each genus. In addition, the syringyl ratio correlated positively with the erythro ratio and acid-soluble lignin content, regardless of the genus. The existence of a clear, high correlation between the syringyl and erythro ratios supports the hypothesis that the aromatic ring type (syringyl ratio) is a decisive factor for controlling the diastereomeric forms of the β-O-4 structure (erythro ratio). Each of the wood samples was also subjected to Kraft pulping, and it was demonstrated that the woods with higher syringyl ratios were easier to delignify. This tendency is reasonably attributed to the high reactivity of the erythro-rich and syringyl-rich β-O-4 structures, and the low lignin content of these syringyl-rich woods.

Characteristic of β-O-4 structures in different reaction wood lignins of Eusideroxylon zwageri T. et B. and four other woody species

Abstract Lignin analyses were performed on the reaction woods of five tropical wood species. The reaction woods of these five species and that of Gnetum gnemon L. (previously reported) were categorized into three types based on eccentric thickening growth and p-hydroxyphenyl/guaiacyl/syringyl (H/G/S) ratios: compression wood (CW) containing GH-lignin observed in gymnosperms (GH-lignin-CW), tension wood (TW) containing GS-lignin observed in angiosperms (GS-lignin-TW), and reaction wood that resembles CW and contains GS-lignin (GS-lignin-CW). GS-lignin-CW is an unusual type that was found in the angiosperm Eusideroxylon zwageri and in the gymnosperm G. gnemon. The erythro/threo ratio of the β-O-4 structures and the S/G ratio were higher on the upper side (usW) of the leaning wood stem or branch, and both ratios decreased along the periphery of the stem toward the lower side (lsW). Except for a difference in thickening growth, these distribution patterns were similar to the GS-lignin-TW patterns for Melia azedarach L. and Avicennia sp. Reaction wood of Paraserianthes falcataria (L.) Nielsen was also classified as a GS-lignin-TW, but this was lacking a clear distribution pattern. In contrast, the GH-lignin-CW of the usW of Pinus merkusii Jungh. et de Vriese had a low erythro/threo ratio, which increased toward the lsW along with increasing lignin contents and H/G ratios.

KAJIAN STRUKTUR ARANG-PIROLISIS, ARANG-HIDRO DAN KARBON AKTIF DARI KAYU Acacia mangium Willd. MENGGUNAKAN DIFRAKSI SINAR-X

Kegunaan karbon aktif sangat luas dan penting untuk beragam aplikasi. Arang-hidro dari biomassa yang dibuat melalui proses karbonisasi hidrotermal merupakan prekursor alternatif terhadap prekursor konvensional untuk pembuatan karbon aktif yang selama ini banyak menggunakan arang dari proses pirolisis (prekursor konvensional). Tulisan ini menganalisa struktur kristalin arang-pirolisis dan arang-hidro suhu 200 ?C dan 300 ?C serta produk karbon aktif menggunakan difraksi sinar-X (XRD). Hasil penelitian menunjukkan bahwa indeks kematangan dan tingkat aromatisasi karbon dari prekursor (baik konvensional atau alternatif) meningkat setelah diaktivasi; jarak antar lapisan graphene (d002) semakin kecil, sementara itu derajat kristalinitas, jumlah, tinggi dan lebar lapisan aromatik semakin besar. Arang-hidro memiliki derajat kristalinitas, indeks kematangan dan tingkat aromatisasi lebih rendah dari arang pirolisis suhu 300?C dengan kandungan bahan mudah menguap lebih tinggi. Keduanya telah membentuk struktur karbon bersifat amorf. Karbon aktif dari arang-hidro suhu 300?C menghasilkan daya jerap iodin tertinggi. Analisis XRD terhadap arang-pirolisis dan arang-hidro suhu rendah dapat memprediksi porositas karbon aktif yang dihasilkan.

STRUKTUR DAN KOMPONEN ARANG SERTA ARANG AKTIF TEMPURUNG KEMIRI

Activatied method of charcoal determines the specific usage of activated charcoal. Generally there recognize two activation methods to produce activated charcoal : physical and chemical methods. This research was carried out to identify structure and components of charcoal and activated charcoal from candlenut shell. Candlenut shell (Aleurites moluccana Willd) was carbonised in drum-kyln to produce charcoal, and then the product was activated in electrical retort by applying thermal activator with heating duration of 120 minutes at temperature of 550 C, 650 C and 750 C respectively. For further investigation, the heats at 750 C was chosed, combined with steam activator by heating duration of 90 minutes and 120 minutes. Fungsional group, crystallinity and porosity of candlenut shell, charcoal and activated charcoals sample test were characterized by Fourier Transform Infra Red FTIR X-Ray Difractometer XRD Scanning Electron Microscope SEM chemical compounds on sample test of candlenut shell, charcoal and activated charcoals Gas Chromatograph Mass Spectrometer Py-GCMS In turned out that activation process brought about changing in fungtional group pattern, increasing in crystallinity, pore opening and chemical compound reduction. The higher activation temperature caused the increase in crystallinity, pore diameter and chemical compound reduction. The activation by steam resulted activated charcoal with relatively cleaner pore. Structure, components, charcoal, activated charcoal, candlenut shell (Aleurites moluccana).

DAUR PATOLOGIS TEGAKAN HUTAN TANAMAN Acacia mangium Willd.

Heart rot on Acacia mangium Willd. forest stand is critical especially for mechanical or construction wood based purposes. Failure on understanding the nature and the way it get established into the tree stem may cause high economic consequences.Anticipating such a worse condition, studies on cull factor in relation to age was initiated. Eventually the study is aimed at healthy cutting cycles of the clear and purposely stand establishment. The study had been carried out at BKPH Parung Panjang, KPH Bogor. Following the cull factor measurement technique combined with the pathological rotation estimation procedures, it was found that the healthy volume was 0.0623 m and the cull factor was 31.25 %.The figures were at the age of nine years. Therefore, the pathological rotation cycle for the A. mangium stand in the area could be fitted at eight years, as being adopted so far.This is true, when the plantation is established for the production of wood, provided that the tending operation is optimal. Applying the United States Department of Agriculture (USDA) Forest Health Monitoring (FHM) indices, the general performance of the A. mangium forest stand in Parung Panjang is found to be in healthy criteria. The damage indices for all stand ages investigated varied from 2.77 (lowest) to 5.16 (highest) as compared to the 21.18 value, the possible highest FHM tree index.