• Journal of the Korean Wood Science and Technology
• /
• v.31 no.6
• /
• pp.31-39
• /
• 2003

The enzymatic isolation of residual lignins obtained from spruce and beech pulps (obtained by sulfite, kraft, ASAM and soda/AQ/MeOH pulping processes) and their characterization was described in previous publications. Here, the residual lignins have been submitted to potassium permanganate oxidation (KMnO₄ degradation), and 9 aromatic carboxylic acids (3 of them are dimeric) were identified after methylation with diazomethane by GC/MS. The analytical challenge during qantification by the internal standard methods was the partly high protein content of the samples, which resulted in elevated anisic acid yields in the degradation mixture of sulfite residual lignins. The results are compared with the KMnO₄ degradation of the corresponding MWLs and discussed in terms of S/G ratios and degrees of condensation. The latter was calculated as a quotient between the aromatic carboxylic acids derived from condensed and non-condensed lignin structures. Typical degradation patterns for the various processes have been observed. Among other parameter, the relative compositions between iso-hemipinic acid (which is for condensation in pos. 5 of the aromatic ring) and meta-hemipinic acid and 3,4,5-trimethoxyphthalic acid (both are for condensation in pos. 6 of the aromatic ring) was found to be process specific. Kraft and soda/AQ/MeOH residual lignins yielded higher amounts of iso-hemipinic acid. In contrast, the relative yields of meta-hemipinic acid and 3,4,5-trimethoxyphthalic acid (the latter in beech lignins) are higher in sulfite and particularly in ASAM residual lignin. In case of beech residual lignins the amount of acids originated from non-condensed syringyl type lignin units was surprisingly high. The condensation degree of residual lignins was shown to be generally higher than that of MWLs. This was especially true for the G units. ASAM residual lignin exhibited very high S/G ratios and degrees of polymerization. Causality between condensation degree and total yield of degradation products was demonstrated.

• Journal of Energy Engineering
• /
• v.20 no.1
• /
• pp.36-43
• /
• 2011

Plant biomass has been proposed as an alternative source of petroleum-based chemical compounds. Especially, aromatic chemical compounds can be obtained from lignin by depolymerization processes because the lignin consist of complex aromatic materials. In this study, kraft lignin, the largest emitted substance among several kinds of lignin in Korea, was used as a starting material and was characterized by solid-state $^{13}C$-Muclear Magnetic Resonance($^{13}C$-NMR), Fourier Transform Infrared Spectroscopy(FT-IR), Elemental Analysis(EA). The depolymerization of kraft lignin was studied at water-phenol mixture solvent in near critical region and the experiments were conducted using a batch type reactor. The effects of water-to-phenol ratio and reaction temperature($300-400^{\circ}C$) were investigated to determine the optimum operating conditions. Additionally, the effects of formic acid as a hydrogen-donor solvent instead of $H_2$ gas were examined. The chemical species and quantities in the liquid products were analyzed using gas chromatography-mass spectroscopy(GC-MS), and solid residues(char) were analyzed using FT-IR. GC-MS analysis confirmed that the aromatic chemicals such as anisole, o-cresol(2-methylphenol), p-cresol(4-methylphenol), 2-ethylphenol, 4-ethylphenol, dibenzofuran, 3-methyl cabazole and xanthene were produced when phenol was added in the water as a co-solvent.

• Journal of the Korean Wood Science and Technology
• /
• v.34 no.6
• /
• pp.36-43
• /
• 2006

Using fluidized bed type fast pyrolysis system (capacity 400 g/h) bio-oils were produced from beech (Fagus sylvatica) and softwood mixture (spruce and larch, 50:50). The pyrolysis was performed for 1~2 s at the temperature of $470{\pm}5^{\circ}C$. Pyrolysis products consisted of liquid form of bio-oil, char and gases. In beech wood bio-oil was formed to ca. 60% based on dry biomass weight and the yield of bio-oil was 49% in soft wood mixture. The moisture contents in both bio-oils were ranged between 17% and 22% and the bio-oil's density was measured to $1.2kg/{\ell}$. Bio-oils were composed of 45% carbon, 47% oxygen, 7% hydrogen and lower than 1% nitrogen,which was very similar to those of original biomass. In comparison with oils from fossil resources, oxygen content was very high in bio-oils, while no sulfur was found. More than 90 low molecular weight components, classified to aromatic and non aromatic compounds, were identified in bio-oils by gas chromatographic analysis, which amounted to 31~33% based on the dry weight of bio-oils.

• KSBB Journal
• /
• v.18 no.1
• /
• pp.30-34
• /
• 2003

A bacterial strain isolated from a compost-packed biofilter after 100 days of operation was identified as Rhodococcus pyridinovorans PYJ-1, with a similarity of 99%. This strain removed benzene, toluene and m-xylene (BTX) at 2~30 mg/L within 6~20 hrs in batch cultures. Optimum pH and temperature for BTX removal were pH 7 and $32^{\circ}C$. This strain also removed a mixture of BTX at component concentrations of 2~5 mg/L.

• Bulletin of the Korean Chemical Society
• /
• v.9 no.5
• /
• pp.322-324
• /
• 1988

Selective reduction of aldoximes and ketoximes with lithium borohydride in tetrahydrofuran was investigated. Thus, aldoximes and cyclic ketoximes such as hexanaldoxime, heptanaldoxime, cyclopentanone oxime and cyclohexanone oxime were reduced smoothly to the corresponding N-monosubstituted hydroxylamines at room temperature in 65-93% yield. The reduction of alicyclic ketoxime was very slow, requiring somewhat high reaction temperature ($65^{\circ}C$) for the complete reduction to give the hydroxnylamines. The reduction of aromatic oximes such as benzaldoxime and acetophenone oxime was very sluggish, giving a mixture of the corresponding hydroxylamines and amines at $65^{\circ}C$.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2004.04a
• /
• pp.297-300
• /
• 2004

The various microbial tests were performed to determine bioremediation agent capacity for eight strains isolated from the oil contaminated regions. Two tests for isolated strains were conducted such as cell hydrophobicity and emulsifying activity. The biodegradation of SHM (saturated hydrocarbon mixture) and AHM (aromatic hydrocarbon mixture) with the strains also was carried out. The strains having higher cell hydrophobicity and emulsifying activity degraded petroleum oil effectively. The degradation capacity for SHM was represented more than 90% in YS-7 and WLH-1 of isolated strains, and KH3-2 were capable of degrading AHM. Especially, WLH-1 as yeast was shown more than two or three times in the degradation capacity of automobile engine lubricants and the biomonitoring results of contaminated soil for residual oil degrading test showed that the hydrocarbon biodegradation was increased in the second treatment by this strain.

• Journal of Environmental Health Sciences
• /
• v.33 no.1 s.94
• /
• pp.63-67
• /
• 2007

Laccase catalyzes the oxidation and polymerization of aromatic compounds in the presence of molecular oxygen. The oxidative transformation of chlorophene with laccase was conducted in a closed, temperature controlled system. The optimal pH for transformation of chlorophene was proven to be about 5-6. As the temperature rose up to $55^{\circ}C$, the transformation of chlorophene increased. The chlorophene transformation was not enhanced in the presence of soluble polymers. The toxicity of the reaction mixture was increased two times than that of initial reaction mixture after the enzymatic treatment. ABTS has enhanced chlorophene transformation at 0.1 mM and showed negative linear relationship with residual chlorophene by the reaction.

• Textile Coloration and Finishing
• /
• v.7 no.4
• /
• pp.39-44
• /
• 1995

A study has been made about some correlations in the chemical cyclization of precursors, poly(ether-amide-amic acid)s by treating in solution a mixture of acetic anhydride and pyridine in the presence of 4,4-dimethyl formamide, with the poly(ether-amic acid)s being respectively reacted between trimellitic anhydride chloride and 3 kinds of diamines, i.e., 4,4'-bis(m-aminophenoxy) benzophenone, 2,2'-bis[4-(m-aminophenoxy) phenyl] propane and 4,4'-bis(m-aminophenoxy) diphenyl sulfone. The cyclization of imide ring in the poly(ether-amide-amic acid)s may be regarded as an intramolecular acylation of amide group by o-carboxyl group. As a result of this reseach, the effects on the conversion to poly(ether-amide-imide)s have been found by changing the ratio of cosolvents in the cyclization mixture.

• Korean Journal of Soil Science and Fertilizer
• /
• v.18 no.1
• /
• pp.38-49
• /
• 1985

The water soluble organic fractions (WSOF) from an agricultural soil (W), a soil treated with sludge for 6 years ($WS_6$), a sludge-soil mixture incubated for one week ($WS_1$), and sewage sludge (SS) were extracted, purified, and characterized by elemental analysis, functional group determinations, infrared, UV-visible, and proton nuclear magnetic resonance spectrosocpy. The SS was characterized by higher organic H, N, and P contents, a higher H/C ratio, and a lower C/N ratio than W. Total acidity carboxyl and phenolic hydroxyl group contents were generally highest in SS, intermediate in $WS_6$ and $WS_1$, and lowest in W. Overall aromatic character and aromatic carboxyl group contents were highest in W, and lowest in SS. Aliphatic proton, aliphatic carboxyl, and phenolic hydroxyl group contents were highest in SS, and lowest in W. Protein decomposition products were the pronounced components in SS, and decreased in concentration as the sludge component in the mixtures decreased. The $^1H$-NMR spectra suggested that the SS-protons were bound to a wider range of functional groups than W-protons. Structural complexities around the aromatic protons followed the following order: SS>$WS_1$>$WS_6$>W.

• Journal of Microbiology and Biotechnology
• /
• v.11 no.3
• /
• pp.435-442
• /
• 2001

Poly(3-hydroxy-5-phenylvalerate) [P(3HPV)] was efficiently accumulated from 5-phenylvalerate (5PV) in Pseudomonas putida BM01 in a mineral salts medium containing butyric acid (BA) as the cosubstrate. A nove aromatic copolyester, poly(5 mol% 3-hydroxy-4-phenylbutyrate-co- 95 mol% 3-hydroxy-6-phenylhexanoate) [P(3HPB-co-3HPC)] was also synthesized from 6-phenylhexanoate (6PC) plus Ba. The two aromatic polymers, P(3HPV) and P(3HPB-co-3HPC), were found to be amorphous and showed different glass-transition temperatures at $15^{\circ}C$ and $10^{\circ}C$, respectively. When the bacterium was grown ina medium containing 20 mM 5PV as the sole carbon source for 140 h, 0.4 g/l of dry cells was obtained in a flask cultivation and 20 wt% of P(3HPV) homopolymer was accumulated in the cells. However, when it was grown with a mixture of 2 mM 5PV and 50 mM BA for 40 h, the yield of dry biomass was increased up to 2.5 g/l and the content of P(3HPV) in the dry cells was optimally 56 wt%. This efficient production of P(3HPV) homopolymer from the mixed substrate was feasible because BA only supported cell growth and did not induce any aliphatic PHA accumulation. The metabolites released into the PHA synthesis medium were analyzed using GC or GC/MS. Two $\beta$-oxidation derivatives, 3-phenylpropionic acid and trans-cinnamic acid, were found in the 5V-grown cell medium and these comprised 55-88 mol% of the 5PV consumed. In the 6PC-grown medium containing Ba, seven ${\beta}$-oxidation and related intermediates were found, which included phenylacetic acid, 4-phenylbutyric acid, cis-4-phenyl-2-butenoic acid, trans-4-phenyl-3-butenoic acid, trans-4-phenyl-2-butenoic acid, 3-hydroxy-4-phenylbutyric acid, and 3-hydroxy-6-phenylhexanoic acid. Accordingly, based on the metabolite analysis, PHA synthesis pathways from the two aromatic carbon sources are suggested.