SU1289869A1 - Method of producing water-soluble azo-derivative hydrolytic lignin - Google Patents

Abstract

The invention relates to the processing of plant materials, in particular the production of a water-soluble as-produced hydrolysis lignin (VL) used for tanning and dyeing leather. To make the water solubility of BA, other source reagents and process conditions are used. VL are obtained by diazotization of oxidized hydrogen oxide and permeated with HNO, hydrolyzed lignin using diazotized salt of 2-aminophenol-4-sulfonic acid with a mass ratio equal to

Description

The invention relates to the processing of plant materials, in particular, to a method for producing a water-soluble azo-derivative hydrolysis. lignin used for tanning and dyeing leather.

The aim of the invention is to increase the solubility of the azo-derivative hydrolytic lignin, which binds skin and has skin and fur properties.

Pr and measures. 10 g of hydrolyzed lignin, purified from oils and resins, dried in air, placed in a round bottom flask equipped with a stirrer, a thermometer and a reflux condenser. 20 ml of nitric acid (p 1.31 g / cm) are poured into the reactor gradually (within 15 minutes) with stirring. After adding the acid, the reaction mass is stirred for 40-50 minutes. The oxidation and nitration reaction of lignin with nitric acid is exothermic, so the reaction mixture is cooled with cold water to remove heat so that the temperature of the mixture does not rise above 80–85 s. At the end of the reaction, the mass is cooled to room temperature, the tan powder of oxidized nitrated lignin is separated from the mother liquor by filtration and washed with water until neutral (Congo). The washed lignin is pressed between sheets of filter paper and air dried to 40-50% moisture.

The diazotization of 2-aminophenol-4-sulphonic acid is carried out according to a known method. In a porcelain cup, 6 g of 2-aminophenol-4-sulfo acid are mixed with 38 g of water until a homogeneous suspension, then 2.3 ml of concentrated hydrochloric acid (p 1.17 g / cm) is added. The beaker with the reaction mixture is placed in an ice bath and a solution of 1.75 g of sodium nitrite in 5 ml of water is added dropwise in 2 hours. The temperature of the reaction mixture should not exceed 4-5 C.

The averaging is carried out in a porcelain cup. An oxidized lignin was used as the azo component, and a 2-aminophenol-4-sulfonic acid diazotized salt was used as the diazo component. Wet oxidized lignin is mixed with 40 ml of 5% sodium hydroxide solution. To 25 ml of an alkaline suspension of lignin, 25 ml of diazo salt are added over 10 minutes;

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20 89869-2

do (5 g), controlling the pH of the medium with a potentiometer in the range of 8.4-9.4. The reaction vessel is placed in a water bath and the temperature of the reaction mass does not rise to Bbmie for 15 s. To prevent foaming, a few drops of isoamyl alcohol are added to the reaction mixture. At the end of the reaction (2 hours), the dark brown solution of ligninose phenol sulfonic acid is evaporated to dryness at 60-70 ° C. The target product (azoxyl) is a black powder, soluble in water at 92.4%.

In tab. Figure 1 shows the effect of the azo coupling reaction temperature on the azoxy solubility (reaction time 2 hours, pH 9.0-9.4, diazo salt / lignin ratio 1: 1).

Table 1

In tab. Figure 2 shows the effect of the azo coupling reaction duration on the azoxy solubility (10 ° C, pH 9.0-9.4, the ratio of diazoxy and lignin 1: 1).

Table 2

Sample,. I Reactivity time - Solubility of № | tion, h IB water,%

50

45

55

61,076,7-81,9

71,579,8-83,6

82,086,8-92,2

92,586,0-89,4 103,084,4-86,8

In tab. Figure 3 shows the effect of the pH of the medium during the azo coupling reaction on the solubility of azoxy (the duration of 2 hours, the ratio of diazo salt and lignin 1: 1).

Table3

In tab. The effect of the diazo salt and lignin ratio on the azoxy solubility (10 ° C, duration 2 hours, pH 9.0-9.4) is shown.

Table 4

Purified Hydrolytic Lignin

From the data table. 5 it follows that, regardless of the nature of the plant material and the purity of the hydrolytic lig5

From the data presented in table. 1-4, it follows that the optimum process temperature is in the range of .5-15 ° C (at a higher

foaming of the reaction mass is observed at a temperature even in the presence of isoamyl alcohol; a decrease in temperature below 5 s leads to a decrease in the solubility of the obtained product); optimal process time .1.5-2 hours (a decrease in the reaction time leads to a decrease in the solution of the product, and increasing the reaction time over 2 hours has little effect on the solubility of the target product); at low pfl, products with poor solubility in water are obtained (16.8-42.8%), with addition of alkali to pH 9.0-9.4, the solubility of azoxyl increases, and with further increase in the alkalinity of the medium decreases; The optimal ratio of the amounts of the diazo component and lignin, which makes it possible to obtain the most soluble azo-derivatives of lignin, (0.6-1): 1.

In tab. 5 shows the data on the study of the solubility of the target product obtained from hydrolytic lignin of various types of plant raw materials: cotton husk, sunflower husk, rice husk, as well as from technical crude hydrolyzed lignin of wood - at t 5 5-15 ° С, -6 2 h ; pH 9.0-9.4; the ratio of diazosols and lignin 1: 1. G Table5

0

five

0

The lignin derivatives of the lignin obtained by the proposed method dissolve well in water.

Water-soluble azo derivatives from hydrolyzed lignins can also be obtained by oxidation with 8% nitric acid with a T module: F 1:10, 43–48 ° C for 6 h.

The maximum solubility of the resulting azo-derivative lignin is 95.6%. However, the oxidation of hydrolyzed lignin with concentrated 50% nitric acid is more technological than the oxidation with dilute (8%) nitric acid. ,

Thus, the proposed method of processing hydrolytic lignin by oxidation with nitric acid and azo-t 5 by titration of the obtained oxidized lignin with diazotized amino derivatives of sulphonic acids allows one to obtain water-soluble azo-derivatives of lignin

ten

wood lignin derivative, obtained under optimal conditions. Concentration of the studied tanning agent in a solution of 5.0-5.5 g / l. The tanning extract is characterized by the following parameters: all soluble 83.8, insoluble 16.2, tannid 48.4, non-tannid 35.4, ash 5.4, good quality 57.75 (in% based on absolute dry matter) . The data are obtained as a result of laboratory analyzes conducted according to the methods of the All-Union single method (BEM).

To characterize the quality of tanning agents, an important point is the determination of sorption indices and irreversibly bound tannids. These values characterize the ratio between the colivation of a wide range of varying quantities of tannins, which preserve

Loviy.

The yield of the target product is 104-112% relative to the starting, hydrolyzed lignin. -H.

The dubbing properties of azo derivatives of hydrolytic lignin are studied for azo dubs for comparison due to the following: oak.ex; rakt is the best domestic natural tanning agent; syntan 12 is the best domestic synthetic tanning agent} syntan ATP is the best synthetic tanning agent based on lignin (sulfite alkali), sulfite-cellulose concentrate is tanning agent based on unmodified sulfite liquors.

From tab. 6 that azoxy, by the amount of sorbed and strongly bound substances, is significantly superior.

wood lignin derivative, obtained under optimal conditions. Concentration of the studied tanning agent in a solution of 5.0-5.5 g / l. The tanning extract is characterized by the following parameters: all soluble 83.8, insoluble 16.2, tannid 48.4, non-tannid 35.4, ash 5.4, good quality 57.75 (in% based on absolute dry matter) . The data are obtained as a result of laboratory analyzes conducted according to the methods of the All-Union single method (BEM).

To characterize the quality of tanning agents, an important point is the determination of sorption indices and irreversibly bound tannids. These values characterize the ratio between colic and collagen after washing with water and the total amount of sorbed substances. These indicators are determined by BEM.

The properties of the proposed tanning agent in comparison with the properties of known tanning substances are presented in Table. 6

Table

Sulphite-cellulose extract rises and is somewhat inferior to oak extract and syntanam 12, ATP.

50

To characterize tannins, the determination of the skin welding temperature is of particular importance. This indicator makes it possible to judge about the effect of Dublin, which is a quantitative characteristic of intermolecular bonds formed between the functional groups of tanning agents and collagen. The more functional groups that can interact with

leather sheepskin coat. Dyeing is carried out by immersing the samples in

protein, contains a tanning agent and the stronger the bonds resulting from this interaction, the better its oak effect.

To determine the temperature, weld the 5 P stirring. After dyeing, samples of sheepskin are used; the sprays are washed in solution with the dye surface solution with a bath module 20, temperature 35–38 ° C for 2 h

ester drying. Some samples are chrome-plated (use 0.5% chromium oxide by weight mole). Tanning is carried out on rocking chairs for 3 days (the dosage of tannins in all cases is 25% of the weight of a mole).

The results of the determination of the welding temperature are presented in table. 7

TA BLS C 7

From the data table. 7, it can be seen that the highest temperature of skin welding for non-chromic mol has syntan 12, and chrome plated has azoxy. This tanning agent increases the temperature of welding of the chrome-plated sole, and Sintan 12 and oak extract, respectively, by 3 and 2 C. The sulphite-cellulose concentrate and Sintan ATP lower the heat resistance of the chrome-plated derma by 3 and 1 ° C. The increased heat resistance acquired by the skin treated with azoxy is apparently due to the formation of additional chrome-tannid bridges between adjacent protein molecular chains.

The study of the dyeing ability of azo derivatives of lignin is carried out on

leather sheepskin coat. Dyeing is carried out by immersing the samples in

dye solution at bath module 20, temperature 35-38 C for 2 h

nosy active substance (1 g / l) at 35-38 ° C, in warm and cold water, then squeezed and dried in air. The amount of dye sorbed on the samples is determined using a leak meter by comparing the brightness of the initial samples and samples after the crashes;

In tab. 8 shows the data characterizing the dependence of the color of the leather with diazotized 2-aminophenol sulphonic acid, in experiments 4-6 - a combination of samples 22-24 with 1,2,4-aminonaphthol sulphonic acid.

Studies show that azo derivatives of lignin can be used to dye the leather of a sheepskin coat brown.

Claims (1)

Invention Formula A method for producing a water-soluble azooperated hydrolytic lignin by reacting a lignin derivative with a diazo-saturated aromatic amine derivative in an alkaline medium, characterized in that, in order to impart a water-soluble 9128986910. For the target product, the salt of 2-aminophenol-4-sulfonic acid derived from lignin is used as an oxide taken in a weight ratio compared to that determined by nitration with nitric acid to the derivative derived lignin (0.6-1): hydrolysing lignin, diazo-: 1, respectively, with S-IS c and tirovanny aromatic aminopro-; 5 pH environment 8.4 - 9.4 for izvodnogo use diazotized 2.0 to 2.5 h t