scholarly journals Single-Flow System for Acid Hydrolysis and Base Condensation

Synfacts ◽  
2021 ◽  
Vol 17 (08) ◽  
pp. 0953
2019 ◽  
Vol 6 (10) ◽  
pp. 105501
Author(s):  
Wreerat Laithong ◽  
Phattarathicha Tepsri ◽  
Sirichai Thepa ◽  
Roongrojana Songprakorp ◽  
Sorachon Yoriya

TAPPI Journal ◽  
2013 ◽  
Vol 12 (11) ◽  
pp. 49-53 ◽  
Author(s):  
CHRISTINE CHIRAT ◽  
LUCIE BOIRON ◽  
DOMINIQUE LACHENAL

Autohydrolysis and acid hydrolysis treatments were applied on mixed softwood chips. The cooking ability was studied by varying the alkali and duration of the cook. Pulps with kappa numbers varying from 30 to 70 were obtained. The bleaching ability of these pulps was studied and compared to control kraft pulps. The prehydrolyzed pulps were shown to be more efficiently delignified by oxygen than the control kraft pulps starting from the same kappa number. Furthermore, the final bleaching was also easier for these pulps. It was also shown that extensive oxygen delignification applied on high-kappa pre-hydrolyzed pulps could be a way to improve the overall yield, which is a prerequisite for the development of such biorefinery concepts. Lignin was isolated from the control kraft and the two pre-hydrolyzed kraft pulps and analyzed by 13C NMR. Lignins from pre-hydrolyzed kraft pulps had similar free phenolic groups content to the control kraft lignin, but their aliphatic hydroxyl groups and β-O-4 content were lower than for the control lignin. The quaternary carbon content was the same for all the samples.


1962 ◽  
Vol 41 (2) ◽  
pp. 234-246 ◽  
Author(s):  
H. J. van der Molen

ABSTRACT A procedure for the quantitative determination of 5β-pregnan-3α-ol-20-one in urine is described. After acid hydrolysis of the pregnanolone-conjugates in urine, the free steroids are extracted with toluene. Pregnanolone is isolated in a pure form as its acetate; after chromatographic separation of the free steroids on alumina, the fraction containing pregnanolone is acetylated and rechromatographed on alumina. Quantitative determination of the isolated pregnanolone-acetate is carried out with the aid of the infrared spectrum recorded by a micro KBr-wafermethod. The reliability of the method under various conditions is discussed under the headings, specificity, accuracy, precision and sensitivity. It is possible to determine 30–40 μg pregnanolone in a 24-hours urine portion with a precision of 25%.


Author(s):  
M. Alekseenko ◽  
V. Litvyak ◽  
A. Sysa ◽  
E. Hrabovska ◽  
O. Galenko

2018 ◽  
Vol 6 (8) ◽  
pp. 520-529
Author(s):  
Aanandsundar Arumugam ◽  
Gedion Habtay ◽  
Haben Kibrom ◽  
Medhanie Gebreamlak
Keyword(s):  

2012 ◽  
Vol 11 (12) ◽  
pp. 2313-2318
Author(s):  
Theodor Malutan ◽  
Adina Elena Panzariu

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