0000000000027908
AUTHOR
J. Hyötyläinen
Characterization of Chlorolignins in Bleached Kraft Pulp Mill Effluents Using Elemental Analysis and Fingerprinting by CuO Oxidation And Hplc
Abstract Elemental analyses and chemical degradation techniques were applied to characterize lignin compounds in different stages of the chlorine bleaching process and in total mill effluent. Ultrafiltration was used for separation of chlorolignins into three nominal molecular weight fractions. Alkaline CuO oxidation products were analyzed by HPLC with diode array detection. Major compounds were identified by reference to authentic compounds. For comparison, native lignins (MWL), kraft lignins, and humic substances were studied as well. The oxygen, carbon and organic chlorine contents were closely similar in the various mill samples and their fractions. In all mill samples, vanillin and 6-c…
Pyrolysis of humic acids from digested and composted sewage sludge
Humic acids (HAs) were extracted from four digested sewage sludge samples composted for four months, one, two and four years. HAs were pyrolyzed at three different temperatures applying both conventional and in situ methylation (ISM) pyrolysis. The pyrolysates were analyzed using gas chromatography-mass spectrometry (GC/MS). Derivatization (ISM) and pyrolysis temperature had dramatic effects on the composition and relative amounts of the pyrolysates. Among the derivatized HA fragments aliphatic compounds prevailed under all the pyrolysis conditions tested. Aromatic substances consisting mainly of guaiacyl-type compounds were detected in higher abundances only at elevated temperatures. Witho…
1H, 13C and 17O NMR spectral study of chlorinated 3,4-dihydroxybenzaldehydes (protocatechualdehydes)
Abstract Chlorinated 3,4-dihydroxybenzaldehydes have been studied by means of 1 H, 13 C and 17 O NMR spectroscopy. The 1 H and 13 C NMR spectral assignments are based on 2-dimensional 13 C- 1 H chemical shift correlation spectroscopy (COSY). The 17 O NMR measurements at natural isotope content in organic solvents are problematic owing to the poor solubility of the compounds and/or broadness of the resonance lines. In aqueous alkaline solutions, however, all protocatechualdehydes exhibit “easy-to-detect” 17 O NMR spectral characteristics. The 17 O NMR chemical shifts in the range of 140–480 p.p.m. are interpreted as arising from the different canonical structures of formyl substituted phenol…
Chemical degradation products of lignin and humic substances part I Synthesis, structure verification and gas chromatographic separation of chlorinated vanillins and syringaldehydes
Abstract Chlorinated vanillins (4-hydroxy-3-methoxybenzaldehydes) and syringaldehydes (3,5-dimethoxy-4-hydroxy-benzaldehydes) were synthesized and their purities and structures were examined by quartz capillary gas chromatography and mass spectrometry. The detailed procedures for the synthesis, gas chromatographic separation and mass spectroscopic features are presented.
Transport of high molecular mass lignin material in the receiving water system of a mechanical pulp mill
High molecular mass material (HMM) of water samples collected from the receiving water system of a mechanical pulp mill was characterized applying cupric oxide oxidation combined with GC and HPLC analysis of the oxidation products. This qualitative method was used to follow the transport of organic HMM discharged by the mill. The interpretation of results was complicated by degradation reactions of HMM in the water system and the assimilation of HMM produced by the mill to natural humic compounds. The analytical data was subjected to the principal component analysis (PCA) to verify the results obtained.
Pyrolysis-GC-MS and CuO-oxidation-HPLC in the characterization of HMMs from sediments and surface waters downstream of a pulp mill
Abstract High molecular mass fractions of lignin and humic compounds in sediments and waters downstream of a pulp mill were characterized applying pyrolysis-gas chromatography-mass spectrometry. The results were compared to those obtained using reversed phase HPLC on the cupric oxide oxidation products. The chromatographic data of both pyrolysis and cupric oxide oxidation were also subjected to the principal component analysis (PCA). The sediment samples and fractions obtained by ultrafiltration of river water samples were freeze dried prior to characterization. The sediment samples were also extracted using 2 M sodium hydroxide solution. The extracts were ultrafiltrated, freeze dried and c…
1H,13C and17O NMR study of chlorovanillins and some related compounds
1H, 13C and 17O NMR chemical shifts and nJ(H,H), 1J(C,H) and 3J(C-6, H-formyl) spin—spin coupling constants of chlorinated vanillins (3-methoxy-4-hydroxybenzaldehydes) were determined. The variation in the long-range 4J(H,H) value between the formyl proton and an ortho-proton suggests that the ortho-substituent strongly forces the formyl group out of the aromatic plane. This can also be observed by considering the 3J(C-6,H-formyl) values and the 13C and 17O NMR chemical shifts. The 17O NMR chemical shifts show a linear correlation with the torsion angle of the formyl group calculated by molecular mechanics. The 13C and 17O NMR chemical shifts of the methoxyl group also possess strong predic…