SE506228C2 - Delignification process with the addition of additives in the form of an aqueous solution comprising phenols and pyrazolidones - Google Patents

Abstract

The present invention relates to a process for the delignification of lignocellulose material, preferably wooden material, for the production of paper pulp. An additive in the state of an aqueous solution of phenols and pyrazolidones is added to the cooking liquor. The aqueous solution is alkaline or acidic and is a residual product from the developing of photographic film or photographic paper.

Description

15 20 25 30 35 506 22s_ 2 vara. Despite the fact that only small amounts of anthraquinone, calculated on the amount of wood, are invested in the cooking, the costs are very high. Why other options are desirable.

Prior art.

U.S. Patent No. 4,213,821 discloses a process utilizing this redox equilibrium.

Anthraquinone compounds are added to the cooking liquid together with reducing agents, such as sodium or zinc additionite, sodium borohydride or zinc powder and sodium hydroxide. In another U.S. patent, A, 4,786,365 pulp is prepared by adding anthraquinone and small amounts of sodium sulfide to the cooking liquid.

Quinones and anthraquinones are effective additives and are stable during the pulping process. The present invention uses the corresponding redox equilibrium, as mentioned above. The compounds of particular interest are various phenols, such as quinone, anthraquinone, aminophenols and others, which are in redox equilibrium with the corresponding keto forms. Preferred phenols are those which have oxidizable groups in the para position. Such phenols may have structural formula I or II: on o H 111 H1 OH NHRQ I II where H, OH,, NH, NHR, SO§, Cl, or Br, H, methyl, ethyl, phenyl, benzyl, or benzone .

The present invention comprises an aqueous solution i.a. containing phenols and pyrazolidones, which are added to the cooking liquid and allowed to participate in the cooking. the aqueous solution is preferably alkaline and is a residual product R1 may be R2 may be from the photo industry and is used for the development of films and photographs. By using these residual products, the costs of the additive can be effectively reduced at the same time as the residual product enters a new industrial cycle and thus does not further burden the environment. .

Pyrazolidones are substances that interact with phenols and enhance their action through improved redox equilibrium.

By improving the redox equilibrium and finding raw materials with a low price, the conditions for the pulp industry improve significantly, as enormous quantities of chemicals are required to cover the production needs.

According to a preferred embodiment of the invention, an aqueous solution of phenols is added in a content between 1 to 50 grams per liter, preferably between 10 to 30 grams per liter, most preferably between 15 to 25 grams per liter, and that the amount of phenols is added in a amount between 0.001% to 10%, preferably between 0.01% to 3%, based on the wood weight. The content of pyrazolidone in the aqueous solution is between 0.1 to 30 grams per liter, preferably between 0.1 to 20 grams per liter, most preferably between 0.1 to 10 grams per liter.

In another preferred embodiment of the invention, the phenols include 1,4-benzenediol, hydroquinone monosulfonate, hydroquinone disulfate, 2-chloro-hydroquinone, 2-bromo-hydroquinone, 4-aminophenol, N- (4-hydroxyphenyl) -glycine monomethyl- p-amino-phenol sulfate or oxidized forms thereof and that the pyrazolidones include 1-phenyl-3-pyrazolidone, 4-methyl-1-phenyl-pyrazolidone, 4-methyl-4-hydroxymethyl-1-phenyl-3-pyrazolidone, 4 , 4-dimethyl-1-phenyl-3-pyrazolidone or redox products thereof.

In a further preferred embodiment of the invention, the aqueous solution is alkaline or acidic.

In a further preferred embodiment of the invention, the aqueous solution also comprises glutaraldehyde, di- or tri-ethylene glycol and / or acetic acid.

In the most preferred embodiment of the invention, the aqueous solution is a residual product from the development of photographic film or photographic paper. The residual product may also contain inorganic substances such as sodium sulphite, sodium hydroxide and sodium carbonate, which are already present in the cooking liquid and are therefore useful for the cooking process.

To investigate the effect of the additive, a comparative study was done, where different amounts of added additive were compared with a conventional sulfate cooker. Two comparative cooking series were made and the results are shown in Tables 1 and 2. The experimental series are not limiting of the invention but illustrate it.

Series 1,300 g Dried industrial softwood chips, with a dry content of 92.5%, were impregnated at 5 bar pressure, followed by boiling for 115 minutes. The boiling was carried out in a rotary wood ratio of 4: 1, an effective alkalinity of 20% calculated on wood and sulphidity of 35%. A boiling autoclave was added to the cooking liquid and various amounts of the "additive" were carried out with a liquid. A boiling temperature of 170 ° C was reached after a temperature increase of 1 ° C / min. At the end of boiling, the masses were washed and dewatered, after which they were analyzed. Analysis data were summarized in Table 1.

Table 1 Boil addi- Kappa- Sila- Spet% Total Visco- no. tiv ml number spout yield site byte%% ml / g 1 O 24.6 44.2 0.8 45.0 - 2 1.5 24.1 43.7 1.0 44.7 - 3 15 24.2 44.8 0.6 45.4 - 4 30 23.9 44.2 0.7 45.0 - 5 75 24.2 44.5 0.6 45.1 - 6 150 24.3 44.5 0, 9 45.3 - 10 15 20 Series 2 Experimental series 2 was carried out under the same conditions and with the same procedure as experimental series 1. The results of the analyzes are shown in Table 2.

Table 2 Boil addi- Kappa- Sila- Spet% Total Visco- no. tiv ml number spout yield site byte%% ml / g 1 O 21.9 43.1 0.5 43.6 1030 2 1.5 23.7 43.5 0.9 44.4 - 3 15 22.3 43.5 o, 9 44.4 1050 "ll 4 30 22.8 43.6 0.9 44.4 - 5 75 25.2 43.6 1.1 44.7 - 6 150 27.0 42.6 1.6 44.2 - The two series of experiments show that the "additive" containing phenols and pyrazolidone increases the yield by 0.4%.

Additives containing phenols and pyrazolidones are therefore of interest in pulp production and are useful alternatives to the expensive conventional additives, such as anthraquinone.

Claims (8)

10 15 20 25 30 35 506 228_ Patent claim Process for delignification of fibrous raw material, preferably wood raw material, in the production of pulp, characterized in that an aqueous solution comprising phenols and pyrazolidones is added to the cooking liquid. Process according to Claim 1, characterized in that the aqueous solution is alkaline or acidic. Process according to Claim 1 or 2, characterized in that the content of phenols in the aqueous solution is between 1 and 50 grams per liter, preferably between 10 and 30 grams per liter, most preferably between 15 to 25 grams per liter, and that the amount of phenols is added in an amount between 0.001% to 10%, preferably between 0.01% to 3%, based on the wood weight. Process according to any one of claims 1-3, characterized in that the content of pyrazolidones in the aqueous solution is between 0.1 to 30 grams per liter, preferably between 0.1 to 20 grams per liter, most preferably between 0.1 to 10 grams per liter. liter. Process according to one of Claims 1 to 4, characterized in that the phenols comprise 1,4-benzenediol, hydroquinone monosulfonate, hydroquinone disulphate, 2-chloro-hydroquinone, 2-bromo-hydroquinone, 4-aminophenol, N- (4- hydroxyphenyl) -glycyl monomethyl p-amino-phenol sulfate or oxidized forms thereof and that the pyrazolidones include 1-phenyl-3-pyrazolidone, 4-methyl-1-phenyl-pyrazolidone, 4-methyl-4-hydroxymethyl-1- phenyl-3-pyrazolidone, 4,4-dimethyl-1-phenyl-3-pyrazolidone or redox forms thereof. Process according to any one of claims 1-5, characterized in that the aqueous solution also comprises glutaraldehyde, di- or tri-ethylene glycol and / or acetic acid. 10 506 228 7 Method according to one of Claims 1 to 6, characterized in that the aqueous solution is a residual product from the development of photographic film or photographic paper. Process for delignifying fibrous raw material, preferably wood raw material, in the production of pulp, characterized in that a residual product from the development of photographic film or photographic paper is added to the cooking liquid and that said residual product comprises phenols and pyrazolidones.