کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9748182 | 1492990 | 2005 | 7 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Chemical characterization of residual lignins from eucalypt paper pulps
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آنالیزی یا شیمی تجزیه
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Chemical characterization of residual lignins from eucalypt paper pulps Chemical characterization of residual lignins from eucalypt paper pulps](/preview/png/9748182.png)
چکیده انگلیسی
Residual lignins were isolated from eucalypt kraft pulps by enzymatic hydrolysis of cellulose followed by purification using a combination of proteinase hydrolysis and solvent extraction. The residual lignins isolated from brown (unbleached) and totally chlorine free (TCF) bleached pulps were analyzed by Fourier-transform infrared (FT-IR) spectroscopy and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), and compared with eucalypt milled-wood lignin and kraft lignin. The lignin in eucalypt wood and pulps showed a strong predominance of syringyl (S) over guaiacyl (G) units. The strongest lignin modification was observed in the kraft lignin recovered from the alkaline pulping liquor. The chemical composition of the residual lignin from pulp was closer to milled-wood lignin than to the kraft lignin, indicating that most of the lignin modified during pulping was released to the cooking liquor. During TCF bleaching of pulp, which included oxygen delignification and peroxide stages, modifications of lignin were produced resulting in increased amount of non-conjugated carbonyl groups. We concluded that residual lignin in eucalypt kraft pulp reflects native lignin moieties entrapped into the cellulosic network thus partially avoiding their attack by chemical reagents, although different modifications are produced during the bleaching stages.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Analytical and Applied Pyrolysis - Volume 74, Issues 1â2, August 2005, Pages 116-122
Journal: Journal of Analytical and Applied Pyrolysis - Volume 74, Issues 1â2, August 2005, Pages 116-122
نویسندگان
David Ibarra, José C. del RÃo, Ana Gutiérrez, Isabel M. RodrÃguez, Javier Romero, MarÃa J. MartÃnez, Ángel T. MartÃnez,