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THERMAL ANALYSIS OF MODIFIED POLYSILICIC ACID WITH AMINO ALCOHOLS
Conclusion. The degree of modification of etha- The ability of sorbents to absorb carbon dioxide also nolamine with solutions ofdifferent concentrations was explains the importance of organic functional groups
determined thermally. The degree ofmodification was in sorption, since the increase is directly proportional
determined as the degree of fragmentation increased. to the increase in the organic content included.
References:
1. Эшмуродов Х. Э., Гелдиев Ю. А., Тураев Х. Х., Умбаров И. А., Джалилов А. Т. Б.Б.Э. Получение и исследование модифицированных глифталевых смол с кремнийорганическим соединением // Universum: технические науки.- Vol. 81.- № 12. 2020.
2. Эшмуродов Х. Э., Гелдиев Ю. А., Тураев Х. Х. Д. А. Т. Синтез и исследование олигомеров на основе эфиров кремниевой кислоты // Universum химия и биология.- Vol. 7.- № 70. 2020.
3. Zhang Y. et al. Adsorption Separation of CO2/CH4 from Landfill Gas by Ethanolamine-Modified Silica Gel // Water. Air. Soil Pollut. Springer Science and Business Media Deutschland GmbH,- Vol. 232.-№ 2. 2021.- P. 1-11.
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https://doi.org/10.29013/AJT-22-3.4-76-81
Khamdamova Dilnoza, Doctoral student of the department "Pulp and Woodworking Technologies" of the Tashkent Institute of Chemical Technology
Umarova Vasila, Doctoral student of the department "Pulp and Woodworking Technologies" of the Tashkent Institute of Chemical Technology
Primkulov Mahmud, Doctor of Technical Sciences Professor of the Department of "Pulp and Woodworking Technologies" of the Tashkent Chemical-Technological Institute
OBTAINING CELLULOSE FROM THE MEDICINAL PLANT MILK THISTLE
Abstract. Cellulose was extracted from the stem of the medicinal plant- milk thistle. The fiber length, sorption properties, physical characteristics of width were studied by the method of IR-spectrum.
Keywords: cellulose, milk thistle, the degree of polymerization, IR-spectrum, the size of cellulose fibers, hydrolysis.
Introduction. It is known that the Institute of tical density of the liquid. As soluble substances are
the Chemistry of Plant Substances named after V.I. released into the solution, the optical density of the
acad. S. Yu. Yunusov AS RUz is concerned with the solution increases, the degree of light transmission
extraction of pharmaceutical substances. The institute decreases (Fig. 1). The kinetics of changes in optical
has developed a number of methods for extracting a density was determined using a KFK-2 photoelec-
variety of medicinal preparations from the flora in Uz- tric colorimeter. After 40-45 minutes, the optical
bekistan. In particular, from the medicinal plant Saint- density of the liquid does not change, which means
Mary-thistle - then milk thistle (Latin Silybum mari- that there is no soluble part in the stems.
anum, in Uzbek Ola o't) [1]. Milk thistle is an annual Objects and research methods. The objects of
or biennial herb. Stem is upright, massive, branched, research are milk thistle stems, cellulose and fiber.
glabrous, slightly branchy, 100-150 cm tall. Its ripe To study the sorption properties of the samples, the
fruits and seeds are raw materials for the production methods of swelling in water and the test method for
of medicines. After the extraction of a number of com- characterizing cellulose fibers were used. And also
pounds, meal remains that is not used [2-4]. the method of IR-spectroscopy was used.
At the beginning, the stems were crushed to 5- The aim of this work - extracting cellulose from
-8 mm, then they were boiled in water to remove milk thistle stems, studying the features of its struc-
easily soluble substances. In this case, soluble sub- ture, determining the size and fractional composi-
stances are released from the stems, changing the op- tion of cellulose fibers.
Figure 1. a) Kinetics of milk thistle stems extraction in water: T-light transmission; D-optical density of the liquid
After separating the soluble part into water, the remaining pulp containing cellulose was cooked. Isolation of cellulose from the mass was carried out by cooking in a 7% alkali solution for 4-5 hours.
Bleaching was carried out in 10% hydrogen peroxide solution for 2 hours. Structural-dimensional characteristics of cellulose from milk thistle, the determination of the size of fibers and the fractional composition in length and width were carried out by an automatic analyzer L&W Fiber Tester, developed by the company "Yuman" [5]. It is known that the length of the fibers has a great influence on the physical properties: strength and elastoplasticity. The instrument allows for advanced analysis of the properties of cellulose fibers.
The analyzer determines the following characteristics of fibers:
- average length of fibers in the sample, mm;
- average width of fibers in the sample, microns;
- average fiber shape factor in the sample;
- average bend angle;
- average number of all kinks per fiber;
- average length of one segment, mm;
- fraction of fines [6; 7].
The device was used to determine the average values of the length and width of the fibers, their frac-
Figure 1. b) Kinetics of milk thistle stems extraction in alkali and peroxide: 1-7% NaOH; 2-10% H2O2 tional composition (distribution curves), as well as the shape factor (Fig. 2).
B
Figure 2. A - Automatic analyzer Fiber Tester; B - micrograph of milk thistle cellulose fibers
3 4 5 Length, ouh|
C) Fiber width, pm D) Shape of the fiber
Figure 3. Fractional composition of milk thistle cellulose samples: a,b - fiber length; c - the width of the fibers; d - the shape of the fibers
Before determining the fiber length distribution are shown in the photo (Figure 2 b). The results
curves in the pulp, using a microscope the type of of distribution curves averaged over the length of
fibers in samples was established. To do this, a fi- the fibers (integral curve 1) and percentage of the
ber sample was diluted with water and applied on fraction (along the length of the differential curve;
the glass surface, after water evaporation, the sizes 2) are shown in (Figure 3). The results of determin-
and shapes of the fibers were photographed. They ing the nature of the fibers are shown in (Table 1).
Table 1.- Structural-dimensional characteristics of cellulose
Variables Weighted average value on the length Weighted average value on the width
Average length 2.5 mm 1.038 mm
Average width 31.2 ^m 22.2 ^m
Shapes average factor 90.8% 80.6%
Cellulose fibers from milk thistle are characterized by a heterogeneous shape of various lengths (Fig. 3); the fraction of long fibers with a length of 3.5 to 7.5 mm reaches more than 0.2, when the
fraction of the rest does not exceed 0.08. The width of the fibers is in the range of 12-35 ^m, then it is probably due to the fact that the stem consists of two different morphological parts - a flat flexible upper
layer (Fig. 4 a) and the middle of a loose white part (Fig. 4 b) in a ratio of approximately 90 : 10.
^_a
^^L —--6
Figure 4. A cross section of the stem of a milk thistle
It is likely that small thin fibers are isolated from the middle part of the stem.
Table 2 - Quality indicators of
Sorption properties and IR-spectroscopy of milk thistle cellulose. After washing and drying, sorption properties of the resulting cellulose were determined, they are shown in (table 2).
From (table 2), it can be seen that the yield of cellulose is 26.0%, swelling in water is 187%, moisture sorption is about 11%, degree of polymerization is 870, ash content is 1.5% and whiteness is about 71%.
Study of IR-spectra of milk thistle cellulose. They are shown in (Figure 5). The spectra were obtained by pressing with KBr on an "IRARAffinity-1" spectrophotometer [8-10].
cellulose from milk thistle stems
yield of cellulose,% Degree of swelling in water,% * Moisture sorption,% Degree of polymerization Ash content,% Whiteness,%
26.0 187 11.0 870 1.5 71.0
1 Relative humidity - 65%
Figure 5. IR-spectra of milk thistle cellulose
Thus, the composition of milk thistle stems contains 26% cellulose with a degree of polymerization of 870, the average length and width of cellulose fibers is 2.5 mm and 22.2 ^m, respectively. [11]
Analysis of the IR-spectra of cellulose shows that in the spectra in the range of3250-3500 cm-1, there is a broad blurry band with intense stretching vibrations caused by OH groups with a hydrogen bond.
Table 3.- Characteristic oscillations in the frequency of functional groups of milk thistle celluloses
Wave number, sm 1 Group Oscillation types Intensity
3750 O-H (H bond is not formed) Valence Very high
3400 O-H (H bond is formed) Valence Broad and intensive
2900 - CH Valence High
2260-2190 - C = N Valence Average
1980 -C = C = C - Asymm. valent High
1465-1400 - CH2 ACHMM. ge^opM.
1400-1350 - CH3 CHMM. ge^opM.
1280-1100 - C-O-C- Asymm. valent Intensive
1075-1020 - C-O-C- Asymm. valent Intensive
Conclusion composition have been determined. Its sorption
A method has been developed for obtaining cel- properties, degree of polymerization, ash content
lulose from the stems of medicinal plant - milk this- and other indicators have been studied. The chemi-
tle. The optimal conditions, the average values of the cal composition of the structures of the formed cel-
length and width of the fibers, and their fractional lulose has been established by IR-spectroscopy.
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