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Umarova Vasila Kabilovna, Doctorant, Tashkent chemical-technological institute Primkulov Makhmut Temurovich, professor of Tashkent chemical-technological institute Baltabayev Ulugbek Narbaevich, associate professor of Tashkent chemical-technological institute, Dean of faculty of chemical technology of organic compounds and fuel
E-mail: Ulug85bek77@mail.ru
OBTAINING CELLULOSE FROM RICE STRAW FOR LIQUID WALL-PAPER
Abstract. A number of works are devoted to obtaining and research of cellulose from annual cereal plants. In order to remove non-cellulose parts of rice straw they were boiled in water, then in acid and alkali solutions. In the infrared region of400-700 cm-1, which is shown in (fig. 3), there are diffuse structurally sensitive bands with several indistinct maxima, which completely disappear only if the crystal structure of cellulose is destroyed. Thus, a method of removing parts easy and difficult to soluble from rice straw by boiling it in water and in solutions of acid and alkali has been developed.
Keywords: cellulose, non-cellulose parts, infrared region, destroyed, rice straw, decoration, spectrum.
Introduction. A number of works are devoted to obtaining and research of cellulose from annual cereal plants [1-4]. The main types of annual plants for the production of cellulose, the preparation of their cooking and cooking conditions are given in the work [1]. Using organic solvent delignification, technical pulp was obtained without the use of chlorine-containing reagents [4]. In the work [2; 3] the study of the structure of cellulose and lignin of annual cereal plants is presented. However, obtaining cellulose to use as a liquid wallpaper is not exposed in the literature.
The purpose of this article is to obtain pulp to use as part of liquid wallpaper, to study the properties and apply for wall decoration.
Methods of study. This article presents a method for delignification, extraction of cellulose from rice straw, the study of some of its physicochemical and structural features using IR-spectroscopy. KFK-2 a
type of IR-spectrophotometer "IRAffinity-1", 2g KBr tablets and a 9 mg sample were used for the study. Well-known sorption methods as well.
Results and discussion. In order to remove non-cellulose parts of rice straw they were boiled in water, then in acid and alkali solutions. Figures 1, 2 show the kinetics of release easily and difficult to dissolve portions of rice straw. During cooking, the substance is released from the composition of rice straw and the optical density of the cooking solution changes. The completion of the isolation process, the optical density of the cooking solution remains constant. This indicates the completion of the release of substances from the composition of rice straw (Fig. 1).
Fig. 1 shows that the ending of the separating process of easily soluble part when boiling in water is completed in about 3.5 hours. In fig. 2 the kinetics of cooking rice straw in a solution of acid and alkali is presented.
Section 4. Chemistry
Figure1. Kinetics of change in optical density when cooking rice straw in water
When boiling rice straw for 50 minutes, the isolation of a substance difficult to soluble from the straw is completed. Moreover, an intense release is observed when boiling in an acid solution (curve 1, fig.2). After removal of the parts easy and difficult to dissolve, the chemical composition of rice straw is calculated:
1. Cellulose content - 47-52%.
2. Lignin - 11-12%.
3. Pentazans - 23-25%
4. Ash content - 16-18%.
5. The content of tar and oil - 1.65-1.75%.
6. The content of substances soluble in water -12.5-13.5%.
Some physical-chemical indicators of rice straw
Table 1
pulp are given in table 1. Physical- chemical indicators of rice straw pulp
Name of indicator Indicators
Swelling in water,% 93,8
Swelling in 17,5% of solution NaOH,% 550
Water retention,% 220
Whiteness,% 56-60
Air permeability, at thickness 250 g/m2, ml/min. 2000-2050
Cellulose swelling in water is about 94%, and about 60%, as the pulp has not been bleached. The in a 17.5% solution of alkali - 550%, water retains IR-spectrum of the cellulose sample was determined more than 2 times its mass. The whiteness is low, (Fig. 3. Table 2).
Figure 3. IR-spectrogram of rice straw cellulose
The IR spectrum was quantitatively processed CH - stretching vibrations). In the region of stretch-
according to the well-known method [5] using the ing vibrations of OH groups, there is a band of about
baseline method and normalized according to the 3250-3500 cm- 1. In the region of1653 cm- 1, absorp-
internal standard - 2950 cm- 1 band (OH -, CH2 and tion of adsorbed water molecules is observed.
Table 2.- IR-spectroscopic characteristics of cellulose samples obtained from rice straw
Assignment Absorption band, cm 1
Valence vibration of OH - groups (with hydrogen bond) 3250-3500
Asymm. valence vibration of -CH3 - groups 2921,57
Asymm. deformation vibration -CH2 - groups 1437,76
Asymm. valence vibration of -C-O-C- groups 1275,52
Valence vibration of - C - OH - groups 1197,20
In the region of900-1500 cm 1, absorption bands located. Here the C-O, C-C stretching vibrations of a complex configuration with several maxima are (~ 1060, 1163 cm-1), the associated vibrations of
Section 4. №emistry
the CH, CH2, and OH-groups (1150-1500 cm-1), as well as the vibrations of the ring (~ 900 cm-1) and C-O stretching vibrations in amorphous regions of cellulose. In the same area, the frequencies of the deformed O-H, CH- and C-OH vibrations appear. In table 2 shows the related absorption bands.
In the infrared region of 400-700 cm-1, which is shown in fig.3, there are diffuse structurally sensitive bands with several indistinct maxima, which completely disappear only if the crystal structure of cellulose is destroyed.
Thus, a method of removing parts easy and difficult to soluble from rice straw by boiling it in water and in solutions of acid and alkali has been developed. Certain physical-chemical parameters of rice straw cellulose were determined. There has been determined through the IR-spectrum that in natural fibers of cellulose almost all hydroxyls are included in the hydrogen bond. Moreover, the low-frequency region of the 3400 cm-1 band characterizes hydroxyls included in the stronger hydrogen bond, and the high-frequency region - in the weaker hydrogen bond.
References:
1. Pulp and paper production technology. T.1. (part 2). Production of semi-finished products, -St. Petersburg: Polytechnic. 2003.
2. Kocheva L. S. Structural organization of the properties of lignin and cellulose of grassy plants of the cereal family. Abstract for the degree of Doctor of Chemical Sciences. Arkhangelsk-2008.
3. Kocheva L. S., Brovarova O. V., Sekushin N. A., Karminov A. P., Kuzmin D. V. Structural and chemical characteristics of non-wood pulp. Lesnoy Journal. 2005.- No. 5.- P. 87-93.
4. Minakova A. R. Production of cellulose by the oxidation-organosolvat method when processing nonwood plant materials. Abstract dis. for candidate of technical sciences - Arkhangelsk. 2008.
5. Jbankov R. G. Infrared spectra and carbohydrate structure.- Minsk. 1972.- 456 p.
