ISSN 1070-4272, Russian Journal of Applied Chemistry, 2006, Vol. 79, No. 10, pp. 1686!1689. + Pleiades Publishing, Inc., 2006.
Original Russian Text + N.I. Afanas’ev, T.F. Lichutina, M.A. Gusakova, G.F. Prokshin, A.P. Vishnyakova, D.A. Sukhov, O.Yu. Derkacheva, 2006,
published in Zhurnal Prikladnoi Khimii, 2006, Vol. 79, No. 10, pp. 1706!1709.
AND POLYMERIC MATERIALS
Estimation of the Content and Assessment of Structural
Transformations of Residual Lignin and Resin
in Deciduous Kraft Pulp by Fourier IR Spectroscopy
N. I. Afanas’ev, T. F. Lichutina, M. A. Gusakova, G. F. Prokshin,
A. P. Vishnyakova, D. A. Sukhov, and O. Yu. Derkacheva
Institute of Environmental Problems of the North, Ural Division,
Russian Academy of Sciences, Arkhangelsk, Russia
St. Petersburg State Technological University of Plant Polymers, St. Petersburg, Russia
Received June 14, 2006
Abstract-Variation of the amount, composition, and structure of the residual lignin and resin in pulp samples
from kraft cooking of birch and aspen woods and their blend with addition of distilled tall oil was studied
by Fourier IR spectroscopy.
The use of deciduous wood, including birch and
aspen wood, in production of kraft pulp involves so-
called [resin problems,] since the content of neutral
substances (styrenes, waxes) in the extractive sub-
stances is 25330%, and that of fats (mainly glycerides
of unsaturated linoleic and oleic acids), 503 60%;
these substances tend to readily transform in storage
and production .
It is well known that, in cooking, the resin content
in deciduous pulp can be decreased by adding various
surfactants, among them products of wood chem-
We studied the possibility of using distilled tall oil
(DTO) and its acidic components for this purpose. It
has been shown previously [3, 4] that, in separate and
combined kraft cooking of birch and aspen wood with
addition of DTO, the content of resinous substances
and residual lignin can be decreased by 303 40%.
To obtain fundamentally new data, we used in this
study a noninvasive method, Fourier IR spectroscopy.
This method is the most informative and allows de-
termination of not only the content, but also structural
transformations of the residual lignin in situ, with-
out its recovery from fibers . Here, we describe
the results of using this method for studying changes
in the composition and structure of residual lignin in
pulp samples from kraft cooking of birch and aspen
wood and their blends with DTO as an additive.
The study was performed with samples of sound
birch (Betula pubesceus) and aspen (Populus tremula)
woods: age 25335 years, stem diameter without
bark 20 cm. For cooking we used hand-made chips of
the following dimensions (mm): length 25330, width
20325, and thickness 233.
The content of extractive substances in birch and
aspen sawdust was the same, 2.5%. The lignin content
determined by the sulfuric acid method was 20.0% in
birch wood and 20.4% in aspen wood; the pulp con-
tent determined by the nitric acid3alcohol method was
45.6 and 50.6%, respectively.
The kraft cookings were performed using white
liquor (sulfide content 30%) in the same tempera-
ture3time mode (heating to 170oC over a period of
120 min, cooking at 170oC for 60 min) in a set of six
pressure vessels. The prescribed expenditure of active
alkali in the Na
O units relative to absolutely dry
wood charged into pressure vessels was 17 wt %. After
the cooking was complete, the pulp was squeezed,
washed on a filter with hot water, and dried in air;
then the pulp yield and resin content were determined
(the latter, by extraction with methylene chloride);
the content of the residual lignin was determined by
the sulfuric acid method, following the standard pro-